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Antibiotics versus placebo for prevention of postoperative infection after appendicectomy.

  1. Betina Ristorp Andersen2,
  2. Finn Lasse Kallehave3,
  3. Henning Keinke Andersen1,*

Editorial Group: Cochrane Colorectal Cancer Group

Published Online: 20 JUL 2005

Assessed as up-to-date: 19 APR 2005

DOI: 10.1002/14651858.CD001439.pub2


How to Cite

Andersen BR, Kallehave FL, Andersen HK. Antibiotics versus placebo for prevention of postoperative infection after appendicectomy.. Cochrane Database of Systematic Reviews 2005, Issue 3. Art. No.: CD001439. DOI: 10.1002/14651858.CD001439.pub2.

Author Information

  1. 1

    Colorectal Cancer Group, Building 11 B,, Copenhagen, Denmark

  2. 2

    Hillerød University Hospital, Department of Obstetrics and Gynecology, Hillerød, Denmark

  3. 3

    Ålborg Hospital, Departement A, Surgical gastroenterology, Ålborg, Denmark

*Henning Keinke Andersen, Building 11 B,, Colorectal Cancer Group, 23 Bispebjerg Bakke, Copenhagen, DK 2400 CPH NV, Denmark. HKA02@bbh.regionh.dk.

Publication History

  1. Publication Status: Edited (no change to conclusions)
  2. Published Online: 20 JUL 2005

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Characteristics of included studies [ordered by study ID]
Ahmed 1987

MethodsRandomised controlled trial. Randomisation method not stated.
Double-blinded. Unclear blinding of outcome assessor.


Participants190 patients enrolled in the study.
Age-range: Treatment group: 10-45, Placebo group: 10-40
Mean: Treatment group: 19,2 +/- 6,7 (s.d.), Placebo group: 21,3 +/- 8,7 (s.d.)
Patients with normal, gangrenous or perforated appendix and antibiotics prior to surgery were excluded before randomisation.


InterventionsTreatment group: Metronidazole 500 mg=100 ml i.v inter-operatively.
Placebo group: Saline 100 ml i.v peroperatively


OutcomesWound infection (Purulent discharge from the incision).


NotesNo drain treatment.


Risk of bias

ItemAuthors' judgementDescription

Allocation concealment?UnclearB - Unclear

Azabache 1987 A

MethodsRandomised controlled trial. Randomisation method stated as simple. Patient and surgeon blinded. Unclear blinding of outcome assesor.


Participants258 eligible patients. 92 excluded before randomisation. 166, 88 males and 78 females enrolled in the study.
Age-range: 6-71
Mean: 23
12 patients excluded after randomisation.
The study has 2 subgroups (see Azabache 1987 B).
In Azabache 1987 A 110 patients enrolled in study.


InterventionsTreatment group: Gentamycin 4 mg/kg and Clindamycin 15 mg/kg one hour inter-operatively hereafter Gentamycin eighthourly and Clindamycin sixhourly for 24 hours if appendix was suppurativ and 72 hours if appendix was gangrenous/perforated.
Placebo group: Not stated. Regime as above.


OutcomesWound infection (Pus in the cellular space under or above the rectusmuscle 3 weeks postoperatively)


NotesNo drain treatment.


Risk of bias

ItemAuthors' judgementDescription

Allocation concealment?UnclearB - Unclear

Azabache 1987 B

MethodsRandomised controlled trial. Randomisation method stated


Participants258 eligible patients. 92 excluded before randomisation. 166, 88 males and 78 females enrolled in the study.
Age-range: 6-71
Mean: 23
12 patients excluded after randomisation.
The study has 2 subgroups (see Azabache 1987 A).
In Azabache 1987 B 110 patients enrolled in study.


InterventionsTreatment group:
Penicilin G 400.000 UI/kg and Chloramphnicol 50 mg/kg one hour intra operatively. Hereafter penicillin G each four hour and chloramphenicol each six hour for 24 hours, if appendix was suppurative and 22 hours if appendix was gangrenous/perforated.
Placebo: Not stated. Regimen as above.


OutcomesWound infection (Pus in the cellular space under or above the rectusmuscle 3 weeks postoperatively)


NotesNo drain treatment.


Risk of bias

ItemAuthors' judgementDescription

Allocation concealment?UnclearB - Unclear

Bates 1980

MethodsControlled clinical trial. Random allocation by the admittiong house surgeon. No blinding of the patient. Adequate blinding of surgeon and unclear blinding of outcome assesor.


Participants200 eligible patients. 30 excluded after randomisation. 170, 90 males and 80 females enrolled in study.
Age-range: 0-90


InterventionsTreatment group: 1 g metronidazole supp 1 hour preoperatively and 1 g supp or orally 8 hourly postoperatively for 7 days. children below 12 received half dose.
Placebo group: No treatment


OutcomesWoundinfection (A frank discharge of pus)
Lenght of stay in hospital


NotesNo drain treatment


Risk of bias

ItemAuthors' judgementDescription

Allocation concealment?NoC - Inadequate

Bauer 1989

MethodsRandomised controlled trial. Randomisation method not stated.
Patient blinded. Unclear blinding of surgeon and out-come assessor.


Participants2387 eligible patients. 652 excluded after randomisation. 1735 enrolled in study.
Age-range: 3 months - 90 years. Mean 23
Patients with allergy to Cefoxitin or Cefalosoprins, moribund, in coma, impaired renal function, shock, antibiotics within 3 days, lactating and pregnant women, younger than 3 months of age were excluded before randomisation.


InterventionsTreatment group: Cefoxitin 2 g (children <12: 40 mg/kg) i.v inter-operatively.
Placebo group: No treatment.


OutcomesWound infection (Discharge of pus from the wounds occurring spontaneously or after incision).
Postoperative intraabdominal absces (Persistent pyrexia without any other focus, after operation, palpable mass in the abdomen or discharge of pus per rectum).
Length of stay in hospital
No postoperative deaths. One died from aorta aneurism, 1 from livercancer and 2 from thrombosis a. mesenterica.


NotesNo drain treatment.
Antibiotics administered 3-5 min before surgery.


Risk of bias

ItemAuthors' judgementDescription

Allocation concealment?UnclearB - Unclear

Bergmark 1985

MethodsRandomised controlled trial. Randomisation method not stated.
Double-blinded. Unclear blinding of out-come assessor.


Participants183 eligible patients. 50 patients excluded after randomisation. 133 patients, 59 males and 74 females enrolled in the study.
Age-range: Treatment group: 16-72, Placebo group: 17-69
Mean: Treatment group 39, Placebo group 36


InterventionsTreatment group: Trimethoprim 240 mg and Sulfametizole 1200 mg and Metronidazole 1,5 g (15 ml) i.v preoperatively.
Placebo group: Saline 0,9% 15 ml i.v preoperatively.


OutcomesWound infection (Pus precent in the wounds or if microbiological culture was positive from a wound opening spontaneously or opened by a surgeon when an infefection was inspected).


NotesNo drain treatment.


Risk of bias

ItemAuthors' judgementDescription

Allocation concealment?UnclearB - Unclear

Browder 1989 A

MethodsRCT, Computer-generated double-blind trial


Participants175 eligible
122 enrolled


InterventionsCeftizoxime, Cefamandole versus placebo given IV pre-op and 6-12 hours after surgery
Three arm study


OutcomesWound infection (not defined)


NotesOnly Pt's with non-perforative appendicitis were enrolled


Risk of bias

ItemAuthors' judgementDescription

Allocation concealment?YesA - Adequate

Browder 1989 B

MethodsAs above


ParticipantsAs above


InterventionsAs above


OutcomesAs above


NotesAs above


Risk of bias

ItemAuthors' judgementDescription

Allocation concealment?UnclearD - Not used

Busuttil 1981 A

MethodsRandomised controlled trial. Randomisation from a masterlist outside the experimential protocol section.
Triple-blinded.


Participants189 eligible patients. 52 patients excluded after randomisation. 136 patients enrolled in study.
Age-range: 4-75, mean 23.
The study has 3 subgroups (see Busuttil 1981 B).
In Busuttil 1981 A 90 patients enrolled in the study.
Patients with perforated appendix, allergy to cephalosporins or penicillins, antibiotic therapy within 72 hours before surgery, pregnacy, inability to 30- days follow-up, serious underlying illnes expected to require antibiotic therapy, were excluded before randomisation.


InterventionsTreatment group: Cefamandole 2 g (children 100-150 mg/kg/day) and Carbenicillin 3 g (children 400-500 mg/kg/day) i.v preoperatively, 4 hours postoperatively and every 6 hour thereafter for 24 hours.
Placebo treatment: Equivalent volumes of dilution i.v preoperatively, 4 hours postoperatively and every 6 hour thereafter for 24 hours.


OutcomesWound infection (Collection of pus drained spontaneously or by incision).
Length of stay in hospital


NotesNo drain treatment.


Risk of bias

ItemAuthors' judgementDescription

Allocation concealment?YesA - Adequate

Busuttil 1981 B

MethodsRandomised controlled trial. Randomisation from a masterlist outsite the experimental protocol section.
Triple-blinded.


Participants189 eligible patients. 52 patients excluded after randomisation. 136 patients enrolled in the study.
Age-range: 4-75, mean 23
The study has 3 subgroups (see Busuttil 1981 A).
In Busuttil 1981 B 91 patients enrolled in the study.
Patients with perforated appendix, allergy to cephalosporins or penicillins, antibiotic therapy within 72 hours before surgery, pregnacy, inability to 30- days follow-up, serious underlying illnes expected to require antibiotic therapy, were excluded before randomisation.


InterventionsTreatment group: Cefamandole 2 g i.v preoperatively, 4 hours postoperatively and every 6 hours thereafter for 24 hours. Children 100-150 mg/kg/day.
Placebo treatment: Equivalent volume of dilution i.v preoperatively, 4 hours postoperatively and every 6 hours thereafter for 24 hours.


OutcomesWound infection (Collection of pus drained spontaneously or by incision).
Length of stay in hospital


NotesNo drain treatment.


Risk of bias

ItemAuthors' judgementDescription

Allocation concealment?YesA - Adequate

Chiam 1983 A

MethodsRandomised controlled trial. Randomisation by random numbers. Double-blinded. Unclear blinding of outcome assessor.


Participants400 eligible patients. 117 excluded after randomisation. 283 enrolled in the study.
All patients above 12 years of age.
Patients already receiving antibiotics or steroids, diabetic and preoperative diagnosis of perforated appendix were excluded before randomisation.
The study has 4 subgroups (see Chiam 1983 B & C).
In Chiam 1983 A 147 patients enrolled in study.


InterventionsTreatment group: Metronidazole 1 g supp preoperatively and eight-hourly for 3 days and Cotrimoxazole 2 ml i.m preoperatively and twice daily for 3 days.
Placebo group: Not specified, but administred as supp and i.m as regime above.


OutcomesWound infection (Pus in the main wound).


NotesPatients with the operative diagnosis of perforated appendix were included in the study.
No comments on drain treatment.


Risk of bias

ItemAuthors' judgementDescription

Allocation concealment?YesA - Adequate

Chiam 1983 B

MethodsRandomised controlled trial. Randomisation by random numbers. Double-blinded. Unclear blinding of outcome assessor.


Participants400 eligible patients. 117 excluded after randomisation. 283 enrolled in study.
All patients above 12 years of age.
Patients already receiving antibiotics or steroids, diabetic and preoperative diagnosis of perforated appendix, were excluded before randomisation.
The study has 4 subgroups (see Chiam 1983 A & C).
In Chiam 1983 B 150 patients enrolled in the study.


InterventionsTreatment group: Metronidazole 1 g supp preoperatively and eight-hourly for 3 days.
Placebo group: Not specified, regime above.


OutcomesWound infection (Pus in the main wound).


NotesPatients with the operative diagnosis of perforated appendix were included in the study.
No comments on drain treatment.


Risk of bias

ItemAuthors' judgementDescription

Allocation concealment?YesA - Adequate

Chiam 1983 C

MethodsRandomised controlled trial. Randomisation by random numbers. Double-blinded. Unclear blinding of outcome assessor.


Participants400 eligible patients. 117 excluded after randomisation. 283 enrolled in the study.
All patients above 12 years of age.
Patients already receiving antibiotics or steroids, diabetic and preoperative diagnosis of perforated appendix, were excluded before randomisation.
The study has 4 subgroups (see Chiam 1983 A & B).
In Chiam 1983 C 134 patients enrolled in the study.


InterventionsTreatment group: Cotrimoxazole 2 ml i.m preoperatively and twice daily for 3 days
Placebo group: Not specified, regime as above.


OutcomesWound infection (Pus in the main wound).


NotesPatients with the operative diagnosis of perforated appendix were included in study.
No comments on drain treatment.


Risk of bias

ItemAuthors' judgementDescription

Allocation concealment?YesA - Adequate

Corbett 1979

MethodsRandomised controlled trial. Randomisation method not stated.
Patient blinded. Unclear blinding of surgeon and outcome assessor.


Participants105 patients enrolled in the study.
Age-range 5-70.


InterventionsTreatment group: Metronidazole 1 g supp preoperatively and eight-hourly for 3 days. (children <14: ½ dosis)
Placebo group: supp regime as above.


OutcomesWound infection (Definite cellulitis and pyrexia, copious seropurulent discharge)


NotesSome patients received drain.


Risk of bias

ItemAuthors' judgementDescription

Allocation concealment?UnclearB - Unclear

Creve 1980 A

MethodsRandomised cotrolled trial. Randomisation by sealed envelopes. Blinding of patients and surgeon. Unclear blinding of outcome assesor.


Participants13 patients enrolled in the study.
Age-range: 18-76


InterventionsTreatment group: Gentamycin 80 mg i.v. inter-operatively.
Placebo group: No treatment


OutcomesWound infection (presense of pus which either spontaneously discharged or required evacuation)


NotesNo comments on drain treatment.
The results are a part of a study including other kind of gastrointestinal sugery.


Risk of bias

ItemAuthors' judgementDescription

Allocation concealment?YesA - Adequate

Creve 1980 B

MethodsRandomised cotrolled trial. Randomisation by sealed envelopes. Blinding of patients and surgeon. Unclear blinding of outcome assesor.


Participants4 patients enrolled in the study.
Age-range: 18-76


InterventionsTreatment group: Gentamycin 80 mg and Clindamycin 600 mg i.v inter-operatively.
Placebo group: No treatment


OutcomesWound infection (presense of pus which either spontaneously discharged or required evacuation)


NotesNo comments on drain treatment.
The results are a part of a study including other kind of gastrointestinal sugery.


Risk of bias

ItemAuthors' judgementDescription

Allocation concealment?YesA - Adequate

Donovan 1979 A

MethodsRandomised controlled trial. Randomisation based on a table of random numbers.
Patient blinded. Unclear blinding of surgeon and outcome-assesor.


Participants250 eligible patients.12 patients were excluded after randomisation. 238 patients were enrolled in the study. All patients above 12 years of age.
The study has 3 subgroups (see Donovan B).
In Donovan 1979 A 153 patients enrolled in the study.
Patients who received antibiotics within the previous 7 days before operation or had allergy to penicillin, were excluded before randomisation.


InterventionsTreatment group: Clindamycin 600 mg i.m preoperatively to the anaesthetized patient.
Placebo treatment: Saline 3 ml i.m preoperatively to the anaesthetized patient.


OutcomesWound infection (Discharge of pus from the wound either spontaneously or after incision).
One patient died 3 months postoperative from pulmonary embolism.


NotesDraining of the wound depending on surgeon. 14 patients in the treatment group were drained, 8 contracted wound infection. 12 patients in the placebo group were drained, 6 contracted wound infection.
Some patients received additional antibiotics starting more than 48 hours postoperatively.
Some patients received additional antibiotics starting within 48 hours postoperatively. They were excluded unless they developed a wound infection.


Risk of bias

ItemAuthors' judgementDescription

Allocation concealment?YesA - Adequate

Donovan 1979 B

MethodsRandomised controlled trial. Randomisation based on a table of random numbers.
Patient blinded. Unclear blinding of surgeon and outcome assessor.


Participants250 eligible patients.12 patients were excluded after randomisation. 238 patients were enrolled in the study. All patients above 12 years of age.
The study has 3 subgroups (see Donovan A).
In Donovan 1979 B 157 patients enrolled in the study.
Patients who received antibiotics within the previous 7 days before operation or had allergy to penicillin, were excluded before randomisation.


InterventionsTreatment group: Cefazoline 1 g i.m preoperatively to the anaesthetized patient.
Placebo treatment: Saline 3 ml i.m preoperatively to the anaesthetized patient.


OutcomesWound infection (Discharge of pus from the wound either spontaneously or after incision).
One patient died 3 months postoperative from pulmonary embolism.


NotesDraining of the wound depending on surgeon. 15 patients in the treatment group were drained, 13 contracted wound infection. 12 patients in the placebo group were drained, 6 contracted wound infection.
Some patients received additional antibiotics starting more than 48 hours postoperatively.
Some patients received additional antibiotics starting within 48 hours postoperatively. They were excluded unless they developed a wound infection.


Risk of bias

ItemAuthors' judgementDescription

Allocation concealment?YesA - Adequate

Eklund 1987

MethodsRandomised controlled trial. Randomisation by a list of random numbers.
Double-blinded. Unclear blinding of outcome assessor.


Participants510 eligible patients, 214 males and 296 females enrolled in the study.
All patients more than 12 years of age.
Patients with perforated appendix, treated with antibiotics for other disease and patients undergoing additional procedure were excluded before randomisation.


InterventionsTreatment group: Tinidazole 2 mg/ ml 200 ml topical peroperatively.
Placebo group: Saline 200 ml topical peroperatively.


OutcomesWoundinfection (Wound discharge visible pus either spontaneously or after debridement).


NotesNo comments on drain treatment.
180 patients had normal appendix.


Risk of bias

ItemAuthors' judgementDescription

Allocation concealment?YesA - Adequate

El-Sefi 1986 A

MethodsRandomised controlled trial. Randomisation based on a table of random numbers.
Patient blinded. Unclear blinding of surgeon and outcome assessor.


Participants480 eligible patients. 80 patients excluded after randomisation. 400 enrolled in the study.
Patients with perforated appendix were excluded after randomisation.
The study has 4 subgroups (see El-Sefi 1986 B & C).
In El-Sefi 1986 A 200 patients enrolled in the study.


InterventionsTreatment group: Metronidazole 500 mg IV preoperatively and eight-hourly for the next 3 days. (When the patient tolerated oral medication converted to 250 orally) and Cefazolin 500 mg i.v preoperatively and eight-hourly for the next 3 days. (When the patient tolerated oral medication converted to 250 orally).
Placebo group: Not specified, same regime as above


OutcomesWound infection (Presence of pus or a purulent exudate of the wound).


NotesNo comments on drain treatment.
Wrote to author to specify subgrouping on drop-outs.


Risk of bias

ItemAuthors' judgementDescription

Allocation concealment?YesA - Adequate

El-Sefi 1986 B

MethodsRandomised controlled trial. Randomisation based on a table of random numbers.
Patient blinded. Unclear blinding of surgeon and outcome assessor.


Participants480 eligible patients. 80 patients excluded after randomisation. 400 enrolled in study.
Patients with perforated appendix were excluded after randomisation.
The study has 4 subgroups (see El-Sefi 1986 A & C).
In El-Sefi 1986 B 200 patients enrolled in the study.


InterventionsTreatment group: Metronidazole 500 mg i.v preoperatively and eight-hourly for the next 3 days. (When the patient tolerated oral medication converted to 250 orally) and Tobramycin 80 mg i.v preoperatively and eight-hourly for the next 3 days. (When the patient tolerated oral medication converted to 80 mg i.m).
Placebo group: Not specified same regime as above.


OutcomesWound infection (Presence of pus or a purulent exudate of the wound).


NotesNo comments on drain treatment
Wrote to author to specify subgrouping on drop-outs.


Risk of bias

ItemAuthors' judgementDescription

Allocation concealment?YesA - Adequate

El-Sefi 1986 C

MethodsRandomised controlled trial. Randomisation based on a table of random numbers.
Patient blinded. Unclear blinding of surgeon and outcome assessor.


Participants480 eligible patients. 80 patients excluded after randomisation. 400 enrolled in the study.
Patients with perforated appendix were excluded after randomisation.
The study has 4 subgroups (see El-Sefi 1986 A & B).
In El-Sefi 1986 C 200 patients enrolled in the study.


InterventionsTreatment group: Metronidazole 500 mg i.v preoperatively and eight-hourly for the next 3 days. (When the patient tolerated oral medication converted to 250 orally)
Placebo group: Not specified same regime as above.


OutcomesWound infection (Presence of pus or a purulent exudate of the wound).


NotesNo comments on drain treatment
Wrote to author to specify subgrouping on drop-outs.


Risk of bias

ItemAuthors' judgementDescription

Allocation concealment?YesA - Adequate

Foster 1978

MethodsRandomised controlled trial. Randomisation based on a computer list kept by the hospital pharmacist. Triple-blinded


Participants165 eligible patients. 26 excluded after randomisation. 139, 74 males and 65 females enrolled in the study. Patients with perforated appendix and different infections such as pelvic inflammatory disease, were excluded after randomisation.
Patients with allergy to penicillin og cephalosporins, antibiotic administration 48 hours before surgery, expectation of need for antibiotic treatment in the immediate postoperative periode and impaired renal or hepatic function were excluded before randomisation.


InterventionsTreatment group: Cephaloridine 50 mg/kg i.m. The first dose given with preanaesthetic medication and postoperatively x4 daily for 2 days.
Placebo group: Not stated: Regime like the treatment group.


OutcomesWound infection (Not defined).


NotesNo comments on drain treatment


Risk of bias

ItemAuthors' judgementDescription

Allocation concealment?YesA - Adequate

Foster 1981 A

MethodsRandomised controlled trial. Randomisation methode not stated.
Doubleblinding. Unclear blinding of outcome assesor.


Participants496 patients enrolled in the study.
The study has 3 subgroups (see Foster 1981 B).
In Foster 1981 A 377 patients enrolled in the study.


InterventionsTreatment group: Metronidasole 1 g supp 40 min preoperatively.
Placebo group: Identical supp 40 min preoperatively.


OutcomesWound infection (not defined)


NotesSome patients got drain treatment.


Risk of bias

ItemAuthors' judgementDescription

Allocation concealment?UnclearB - Unclear

Foster 1981 B

MethodsRandomised controlled trial. Randomisation methode not stated.
Blinding of patient. No blinding of surgeon and unclear blinding of outcome assesor.


Participants496 patients enrolled in the study.
The study has 3 subgroups (see Foster 1981 A).
In Foster 1981 B 236 patients enrolled in the study.


InterventionsTreatment group: Povidone iodine dry powder per-operatively.
Placebo group: Nothing


OutcomesWound infection (not defined)


NotesSome patients got drain treatment.


Risk of bias

ItemAuthors' judgementDescription

Allocation concealment?UnclearB - Unclear

Giacomantonio 1982

MethodsRandomised controlled trial. Randomisation by random numbers in the pharmacy.
Triple-blinded.


Participants42 enrolled in the study.
Age-range: Pediatric.
Only patients with acute appendicitis without perforation.
Patients allergic to penicillin og cephalosporin were excluded before randomisation.


InterventionsTreatment group: Cefamandole 25 mg/kg i.v / i.m preoperatively and immediately postoperatively and 6 hours later.
Placebo group: Not specified, same regime as above.


OutcomesWound infection (Presence of pus in the wound or wound pain, tendernes or erythema or sufficient magnitude to interfere with the patient´s well-being or to prolong hospital stay).


NotesNo comments on drain treatment.


Risk of bias

ItemAuthors' judgementDescription

Allocation concealment?YesA - Adequate

Gledhill 1983

MethodsClinical controlled trial. Allocation according to the month of their day of birth.
Blinding unclear.


Participants102 enrolled in the study.
mean: Treatment group: 24,9, placebo group: 26,2
Patients with weight less than 25 kg, pregnant women or steroid treatment were excluded before randomsation.


InterventionsTreatment group: Cefamandole 2 g i.v inter-operatively.
Placebo group: Nothing.


OutcomesWound infection (Not defined).


NotesAlle patients received drain treatment.


Risk of bias

ItemAuthors' judgementDescription

Allocation concealment?NoC - Inadequate

Go 1986

MethodsRandomised controlled trial. Randomisation method not stated.
Doubleblinded. unclear blinding of outcome assesor.


Participants159 patients enrolled in the study.
Age-range: 12-79, Mean: 29,6


InterventionsTreatment group: Metronidazole 1 g in 100 ml saline IV inter-operatively.
Placebo group: Saline 100 ml inter-operatively.


OutcomesWound infection (not defined)


NotesNo comments on drain treatment.


Risk of bias

ItemAuthors' judgementDescription

Allocation concealment?UnclearB - Unclear

Gottrup 1979

MethodsRandomised controlled trial. Randomisation by random numbers.
Double-blinded


Participants426 eligible patients. 20 patients were excluded after randomisation. 406 patients enrolled in the study. Age-range 5->50.
Patients with allergy to metronidazol, pregnant women, patients with blood dyscrasia, active disease of the central nervous system or alcoholism were excluded before randomisation.


InterventionsTreatment group: Metronidazole 500 mg = 100 ml i.v preoperatively.
Placebo group: 100 ml saline i.v preoperatively.


OutcomesWound infection (Superficial accumulation of pus requiring surgical drainage).
Postoperative intraabdominal abscess (Pyrexia, postoperatively for more than 72 hours, and for wich all other causes could be excluded; Abdominal tenderness or distension; Discharge of pus per rectum).


NotesNo drain treatment.


Risk of bias

ItemAuthors' judgementDescription

Allocation concealment?YesA - Adequate

Greenall 1979

MethodsRandomised controlled trial. Randomisation method not stated.
Double-blinded. Unclear blinding of outcome-assessor.


Participants116 eligible patients. 16 excluded before the code was broken. 111 patients, 51 males and 49 females enrolled in the study.
Age-range 5-73.
Mean 22 +/- 15 (s.d.) in treatment group, +/- 14 (s.d.) in placebo group.


InterventionsTreatment group: Metronidazole 500 mg in 100 ml saline i.v preoperatively.
Placebo group: Saline 100 ml i.v preoperatively.


OutcomesWound infection (Discharge of pus form the wound).


NotesDraining of the wound depending on surgeon. 5 patients in the treatment group were drained, none contracted wound infection. 9 patients in the placebo group were drained, 3 contracted wound infection.


Risk of bias

ItemAuthors' judgementDescription

Allocation concealment?UnclearB - Unclear

Griffiths 1976

MethodsRandomised controlled trial. Randomisation method not stated.
Triple-blinded.


Participants28 enrolled in the study.
Patients with antibiotic treatment prior to surgery, pregnant women, or impaired renal function were excluded before randomisation.
Patients with perforated appendix were excluded after randomisation.


InterventionsTreatment group: Tobramycin 1,5 mg and Lincomycin 600 mg in 500 ml saline i.v peroperatively.
Placebo group: No treatment


OutcomesWound infection (Severe: Purulent discharge, cultures positive for potential pathogens; Mild: Erythema, scanty pus, cultures positive; Colonised: Not clinical infected, cultures positive).


NotesTreatment beginning at the time of skin incision .


Risk of bias

ItemAuthors' judgementDescription

Allocation concealment?UnclearB - Unclear

Gurry 1976

MethodsClinical controlled trial. Randomisation method not stated. Tripleblinded


Participants29 patients enrolled in study. All patients had perforated appendix


InterventionsActive group: Noxytioline 2,5 g in 100 ml saline instilled in the peritoneal cavity and the wound immediately before closure.
Placebo group: 100 ml saline instilled into the peritoneal cavity and the wound immediately before closure.


OutcomesWoundinfection (Not defined).
Length of stay in hospital


NotesNo drainage in either group.
Postoperative antibiotics were used in two control patients and in one patient in the treatment group. (Persisting peritonitis, chest infection, septicaemia)


Risk of bias

ItemAuthors' judgementDescription

Allocation concealment?UnclearB - Unclear

Harnoss 1986

MethodsRCT double blind


Participants175 eligible Pts
145 enrolled
No children under the age of 14 years of age


InterventionsOne shot 500 mg Metronidazole peri-operative, IV
versus placebo (not stated)


OutcomesWound infection in simple appendicitis


NotesNo perforated appendicitis are included.
An overview of other studies are described in table 4


Risk of bias

ItemAuthors' judgementDescription

Allocation concealment?UnclearD - Not used

Hutchinson 1983

MethodsRandomised controlled trial. Randomisation by numbered envelopes.
Double-blinding. Unclear blinding af outcome assessor.


Participants145 eligible patients. 12 excluded after randomisation. 133 patients, 91 males and 42 females enrolled in the study.
Age-range: 16 months - 15 years of age. Mean 6,7


InterventionsTreatment group: Metronidazole (0-3 years 125 mg, 3-6 years 250 mg, 7-15 years 500 mg) supp. preoperatively and eight-hourly for the next 72 hours.
Placebo group: Supp. preoperatively and eight-hourly for the next 72 hours.


OutcomesWound infection (Discharge of pus from the wounds).
Postoperative intraabdominal abscess (Not defined).


NotesNo comments on drain treatment.


Risk of bias

ItemAuthors' judgementDescription

Allocation concealment?YesA - Adequate

Keiser 1983

MethodsRandomised controlled trail. Randomisation by random numbers.
Double-blinded. Unclear blinding of outecome assessor.


Participants98 eligibel patients, 26 excluded after randomisation. 98 enrolled in the study.
Age-range: 15-60. Mean: 27,5
Patients with active neurologic diseasis, blodd dyscrasia, hypothyroidism, hypoadrenalism, were pregnant, and patients who refused to enter the stydy were excluded.


InterventionsTreatment group: Metronidazole 1 g IV preoperatively and 500 mg eight-hourly 5 times.
Placebo treatment: Not specified. Regime as above.


OutcomesWound infection (Wound erythema, definitely infected or purulent discharge).
Length of stay in hospital


NotesNo comments on drain treatment.


Risk of bias

ItemAuthors' judgementDescription

Allocation concealment?YesA - Adequate

Kekomäki 1983

MethodsRandomised clinical controlled trial on children


Participants115 eligible
91 enrolled
24 excluded due to various reasons


Interventionsmetronidazole versus placebo rectal suppositorium prior to surgery and 4 days follow up


OutcomesWound infection (not defined)


Notes


Risk of bias

ItemAuthors' judgementDescription

Allocation concealment?UnclearB - Unclear

Kizilcan 1992 A

MethodsRandomised controlled trial. Randomisation method not stated.
Patient blinded. Unclear blinding of surgeon and outcome assessor.


Participants100, 66 males and 34 females enrolled in the study.
Age-range: 0-15.
Patients presenting parameters suggesting complicated appendicitis were not included.
The study has 4 subgroups (see Kizilcan 1992 B & C).
In Kizilcan 1992 A 50 patients enrolled in study study. 5 patients excluded after randomisation.


InterventionsTreatment group: Ornidazole 20 mg/kg/day divided in 2 doses initiated preoperatively.
Placebo group: Not specified in same regime as above


OutcomesWound infection (Not defined).
Postoperative intraabdominal abscess (Not defined).


NotesNo drain treatment.
Wrote to author to specify subgrouping on drop-outs.


Risk of bias

ItemAuthors' judgementDescription

Allocation concealment?UnclearB - Unclear

Kizilcan 1992 B

MethodsRandomised controlled trial. Randomisation method not stated.
Patient blinded. Unclear blinding of surgeon and outcome assessor.


Participants100, 66 males and 34 females enrolled in the study.
Age-range: 0-15.
Patients presenting parameters suggesting complicated appendicitis were not included.
The study has 4 subgroups (see Kizilcan 1992 A & C).
In Kizilcan 1992 B 50 patients enrolled in the study. 5 patients excluded after randomisation.


InterventionsTreatment group: Penicillin 200.000 U/kg/day divided in 8 doses and Tobramycine 4 mg/kg/day divided i 3 doses initiated preoperatively.
Placebo group: Not specified in same regime as above


OutcomesWound infection (Not defined).
Postoperative intraabdominal abscess (Not defined).


NotesNo drain treatment.
Wrote to author to specify subgrouping on drop-outs.


Risk of bias

ItemAuthors' judgementDescription

Allocation concealment?UnclearB - Unclear

Kizilcan 1992 C

MethodsRandomised controlled trial. Randomisation method not stated.
Patient blinded. Unclear blinding of surgeon and outcome assessor.


Participants100, 66 males and 34 females enrolled in the study.
Age-range: 0-15.
Patients presenting parameters suggesting complicated appendicitis were not included.
The study has 4 subgroups (see Kizilcan 1992 A & B).
In Kizilcan 1992 A 50 patients enrolled in the study. 6 patients excluded after randomisation.


InterventionsTreatment group: Piperacillin Na 200 mg/kg/day divided in 3 doses initiated preoperatively.
Placebo group: Not specified in same regime as above


OutcomesWound infection (Not defined).
Postoperative intraabdominal abscess (Not defined).


NotesNo drain treatment.
Wrote to author to specify subgrouping on drop-outs.


Risk of bias

ItemAuthors' judgementDescription

Allocation concealment?UnclearB - Unclear

Kortelainen 1982

MethodsClinical controlled trial. Allocation based on the last digit of the patients birth year.


Participants315 eligible patients, 278 enrolled. Age range 15-83 years, 159 males and 119 females


InterventionsTreatment group: Metronidazole suppository (1 g) 30-60 min preoperatively.
Control group: No antimicrobial therapy


OutcomesWound infection, defined as the presence of pus or a purulent exudate at the wound


NotesAppendicitis defined as either normal, inflamed or gangrenous


Risk of bias

ItemAuthors' judgementDescription

Allocation concealment?NoC - Inadequate

Leigh 1976

MethodsClinical controlled trial. Randomisation method not stated. Double-blinded.


Participants200 patients, 103 males and 97 females enrolled in study. Age-range 0->40. Patients with macroscopic perforation of the appendix, pre-existing peritonitis or abscess formation were excluded.


InterventionsTreatment group: Lincomycin 600 mg = 2 ml i.m following closure of the wound.
Control group: Saline 2 ml i.m following closure of the wound.


OutcomesWound infection (Discharge of purulent fluid from the operation wound with associated inflammation of the skin edges).
Postoperative intraabdominal abscess (Not defined).


Notes6 patients in the treatment group and 2 patients in the placebo group had microscopic perforation of the appendix.
Draining of the wound depending on the surgeon. 8 patients in the treatment group were drained, none contracted wound infection. 6 patients in the placebo group were drained, 5 contracted wound infection.
11 patients in each group recieved additional antibiotics (Wound infection, urinary tract infection, postoperative chest infection).


Risk of bias

ItemAuthors' judgementDescription

Allocation concealment?UnclearB - Unclear

Morris 1980 A

MethodsRandomised controlled trial. Randomisation by a list of random numbers.
Double-blinded. Unclear blinding of outcome-assessor.


Participants340 eligble patients. 69 excluded after randomisation. 271 patients enrolled in the study.
The study has 4 subgroups (see Morris 1980 B & C).
In Morris 1980 A 133 patients enrolled in study.
All patients above 14 years.
Patients with diabetes or who received antibacterial or steroid treatment or had severe peritonitis requiring antibacterial therapy or had allergy to cephalosporin, were excluded before randomisation.


InterventionsTreatment group: Metronidazole 1 g suppositorium preoperatively and eight-hourly to a total of four doses.
Placebo group: Supp. preoperatively and eight-hourly to a total of four doses.


OutcomesWound infection (Presence of pus in the wounds).


NotesNo comments on drain treatment.
Wrote to author to specify subgrouping on drop-outs.


Risk of bias

ItemAuthors' judgementDescription

Allocation concealment?YesA - Adequate

Morris 1980 B

MethodsRandomised controlled trial. Randomisation by a list of random numbers.
Double-blinded. Unclear blinding of outcome-assessor.


Participants340 eligible patients. 69 excluded after randomisation. 271 patients enrolled in the study.
The study has 4 subgroups (see Morris 1980 A & C).
In Morris 1980 B 137 patients enrolled in the study.
All patients above 14 years.
Patients with diabetes or who received antibacterial or steroid treatment or had severe peritonitis requiring antibacterial therapy or had allergy to cephalosporin, were excluded before randomisation.


InterventionsTreatment group: Cefazolin 500 mg IV / IM preoperatively and eight-hourly to a total of four doses.
Placebo group: An injection i.v /i.m preoperatively and eight-hourly to a total of four doses.


OutcomesWound infection (Presence of pus in the wounds).


NotesNo comments on drain treatment.
Wrote to author to specify subgrouping on drop-outs.


Risk of bias

ItemAuthors' judgementDescription

Allocation concealment?YesA - Adequate

Morris 1980 C

MethodsRandomised controlled trial. Randomisation by a list of random numbers.
Double-blinded. Unclear blinding of outcome-assessor.


Participants340 eligble patients. 69 excluded after randomisation. 271 patients enrolled in the study.
The study has 4 subgroups (see Morris 1980 A & B).
In Morris 1980 C 133 patients enrolled in the study.
All patients above 14 years.
Patients with diabetes or who recieved antibacterial or steroid treatment or had severe peritonitis requiring antibacterial therapy or had allergy to cephalosporin, were excluded before randomisation.


InterventionsTreatment group: Metronidazole 1 g suppositorium and Cefazolin 500 mg i.v / i.m preoperatively and eight-hourly to a total of four doses.
Placebo group: Supp. and injection i.v / i.m preoperatively and eight-hourly to a total of four doses.


OutcomesWound infection (Presence of pus in the wounds).


NotesNo comments on drain treatment.
Wrote to author to specify subgrouping on drop-outs.


Risk of bias

ItemAuthors' judgementDescription

Allocation concealment?YesA - Adequate

Paakkonen 1982

MethodsRandomised controlled trial. Randomisation by the anaesthetist.
Double-blinded. Unclear blinding of outcome-assessor.


Participants158 eligible patients. 27 patients excluded after randomisation. 131, 68 males and 63 females enrolled in the study.
Age-range: Treatment group 15-85, placebo group 15-80.
Mean: Treatment group 39,7, placebo group 35,5


InterventionsTreatment group: Metronidazole 500 mg IV preoperatively.
Placebo group: Saline 100 ml i.v preoperatively.


OutcomesWound infection (Accumulation of pus with spontanously or surgical drainage).
Postoperative intraabdominal abscess (Not defined).
Length of stay in hospital


NotesNo drain treatment.
Patients with perforated appendix all received antibiotics. That subgroup is excluded from this review.


Risk of bias

ItemAuthors' judgementDescription

Allocation concealment?YesA - Adequate

Raahave 1970

MethodsRandomised controlled trial. Randomisation method not stated.
Double-blinded. Unclear blinding of outcome assessor.


Participants30 eligible patients. 2 patients excluded after randomisation. 28 enrolled in the study
Age-range: 3-70.
All patients had perforated appendix.


InterventionsTreatment group: Kanamycin 250-1000 mg depending on S-crea. first dosis topical, hereafter im.
Placebo group: Saline, regime as above.


OutcomesWound infection (Not defined).
Postoperative intra abdominal absces (Not defined).
Length of stay in hospital
No mortalities.


NotesNo comments on drain treatment.


Risk of bias

ItemAuthors' judgementDescription

Allocation concealment?UnclearB - Unclear

Richards 1981

MethodsRandomised controlled trial. Both surgeon and outcome assessor are blinded


Participants143 eligible
129 enrolled
of which 55 had appendectomy


InterventionsGentamycin and glindamycin versu placebo


Outcomespost-operative infection


Notes


Risk of bias

ItemAuthors' judgementDescription

Allocation concealment?UnclearB - Unclear

Rodgers 1979

MethodsRandomised controlled trial. Randomisation method not stated.
Patient blinded. Unclear blinding of surgeon and outcome assessor.


Participants102 eligible patients. 12 patients were excluded after randomisation. 90 patients enrolled in the study.


InterventionsTreatment group: Metronidazole 1 g suppositorium preoperatively and herafter 8 hourly the next 2 days.
Placebo group: Witepsol supp preoperatively and hereafter 8 hourly the next 2 days.


OutcomesWound infection (Pus or purulent exudate at the wound).
Postoperative intra abdominal abscess (Not defined).


NotesDraining of the wound depending on purulent peritoneal exudate, gangrenous/perforated appendix. 8 patients in the treatment group were drained, none contracted wound infection. 4 patients in the placebo group were drained, 3 contracted wound infection.


Risk of bias

ItemAuthors' judgementDescription

Allocation concealment?UnclearB - Unclear

Rowlands 1982

MethodsRandomised controlled trial. Randomisation method not stated.
Triple-blinded.


Participants71 patients enrolled in the study.
Patients who were pregnant, clinical jaundiced, had chronic liver or renal disease, astma, eczema, impaired eight nerve function, had already recieved antibiotics or hypersensitivity were excluded before randomisation.


InterventionsTreatment group: Clindamycin 600 mg IV and Gentamycin 120 mg peroperatively. (=150 ml)
Placebo group: Glucose 150 ml i.v peroperatively


OutcomesWound infection (Discharge of purulent material from the wound or stitch sites or a nonpurulent discharge from wich a positive bacteriological culture was obtained).


NotesDrain treatment depending on surgeon.


Risk of bias

ItemAuthors' judgementDescription

Allocation concealment?UnclearB - Unclear

Saario 1981

MethodsClinical controlled trial. Allocation based on the last digit of the patients birth year.


Participants203 eligible patients. 23 patients excluded after randomisation. 180 patients, 111 males and 69 females enrolled in the study.
All patients above 6 years of age.
Mean: Treatment group: 28,7 +/- 16,3 (s.d), Placebo group: 28,3 +/- 14,7 (s.d).
Patients with perforated appendix, receiving antibiotics 7 days before surgery, pregnant women, or active neurologic disease, were excluded before allocation.


InterventionsTreatment group: Metronidazole 500 mg IV (children half dose) inter-operatively after the surgeon had seen the state of the appendix.
Placebo group: Nothing


OutcomesWound infection (Discharge of pus from the wound either spontaneously or after incision).
Postoperative intra abdominal abscess (Not defined).
Length of stay in hospital


NotesNo comments on drain treatment.


Risk of bias

ItemAuthors' judgementDescription

Allocation concealment?NoC - Inadequate

Salo 1981

MethodsRandomised controlled trial. Randomisation method not stated.
Double-blinded. Unclear blinding of outcome assessor.


Participants223 eligible patients. 2 patients excluded after randomisation. 221 enrolled in the study.
Mean: Treatment group: 32,6, Placebo group: 32,7


InterventionsTreatment group: Tinidazole 500 mg in 100 ml saline i.v preoperatively.
Placebo group: Saline 100 ml properatively.


OutcomesWound infection (Presence of pus in the operation wound requiring surgical incision)


NotesNo comment on drain treatment.


Risk of bias

ItemAuthors' judgementDescription

Allocation concealment?UnclearB - Unclear

Sole 1982

MethodsRandomised controlled trial by use of sealed envelope.


Participants231 eligible pts 113 enrolled
withdrawals not stated


Interventions500 mg Metronidazole one shot peri-operatively. IV versus control


OutcomesWound infection (Presence of pus in the operation wound requiring


NotesNo children under the age of 12 years


Risk of bias

ItemAuthors' judgementDescription

Allocation concealment?YesA - Adequate

Stoller 1965

MethodsRandomised controlled trial. Randomisation by random cards. Triple-blinded.


Participants84 enrolled in the study.
Patients who were given systemic antibiotic immediate postoperatively were excluded after randomisation.


InterventionsTreatment group: Polybactrim spray, topical after closure of peritoneum.
Placebo group: Not specified, regime as above.


OutcomesWoundinfection (An inflammatory erythema in clear excess of normal healing process or if serum or pus discharged from the wound).


NotesNo drain treatment.


Risk of bias

ItemAuthors' judgementDescription

Allocation concealment?YesA - Adequate

Söderquist 1995 A

MethodsRandomised controlled trial
Randomisation method not stated


Participants857 eligible patients. 313 patients excluded after randomisation.
544 patients enrolled in study. Alle children.
Patients with perforated appendicitis were excluded. Patients allergic to antibiotics or recieving antibiotic within 72 hours before surgery were excluded. 193 patients received treatment compared to 176 in the control group


InterventionsTreatment group: metronidazole 20 mg/ kg IV 1 hour preoperatively.
Placebo group: No treatment


OutcomesWound infection (subcutaneus abscess with suppuration confirmed by spontaneus wound rupture debriemnt or incision)
Intrabadominal absces (absces within the intraabdominal cagvity diagnosed at operation or by rectal examination, x-ray or ultrasound)


NotesNo comment on drain treatment


Risk of bias

ItemAuthors' judgementDescription

Allocation concealment?UnclearB - Unclear

Söderquist 1995 B

MethodsRandomised controlled trial
Randomisation method not


Participants857 eligible patients. 313 patients excluded after randomisation.
544 patients enrolled in study. Alle children.
Patients with perforated appendicitis were excluded. Patients allergic to antibiotics or recieving antibiotic within 72 hours before surgery were excluded. 175 patients received treatment compared to 176 in the control group.


InterventionsTreatment group: Metronidazole 20 mg/kg + cefuroxime 50 mg/kg iv 1 hour preoperatively.
Placebogroup: no treatment


OutcomesWound infection (subcutaneus abscess with suppuration confirmed by spontaneus wound rupture debriemnt or incision)
Intrabadominal absces (absces within the intraabdominal cagvity diagnosed at operation or by rectal examination, x-ray or ultrasound)


NotesNo comment on drain treatment


Risk of bias

ItemAuthors' judgementDescription

Allocation concealment?UnclearB - Unclear

Tanner 1980

MethodsRandomised controlled trial. Randomisation method not stated.
Patient blinded. Unclear blinding of surgeon and outcome-assessor.


Participants111 eligible patients. 7 patients excluded. 104, 51 males and 53 females enrolled in the study.
Age-range 8-71
Mean: Treatment group: 26 +/- 14 (s.d.), placebo group: 25 +/- 15 (s.d)


InterventionsTreatment group: Metronidazole 1 g suppositorium preoperatively.
Placebo group: Glycerine supp preoperatively.


OutcomesWound infection (Presence of pus or a purulent exudate at the wound).


NotesDrain treatment to all patients with perforated appendix.


Risk of bias

ItemAuthors' judgementDescription

Allocation concealment?UnclearB - Unclear

Viitanen 1984 A

MethodsClinical controlled trial. Allocation by birthday.
Patient blinded. Unclear blinding of surgeon and outcome assessor.


Participants588 eligible patients. 123 excluded after randomisation. 465 enrolled in the study.
Age-range: 15-94 Mean: 33,4
315 enrolled in this part of the study.
The study has 3 subgroups (see Viitanen 1984 B).
In Viitanen 1984 A 315 patients enrolled in study.


InterventionsTreatment group: Tinidazole 500 mg in 100 saline i.v preoperatively.
Placebo group: No treatment.


OutcomesWound infection (Pus from the wounds).
Two patients died, 1 of peritonitis induced by perforation of the appendix, 1 died of cardiac infarction.


NotesTreatment initiated on anaesthetized patient.
No drain treatment.


Risk of bias

ItemAuthors' judgementDescription

Allocation concealment?NoC - Inadequate

Viitanen 1984 B

MethodsClinical controlled trial. Allocation by birthday.
Patient blinded. Unclear blinding of surgeon and outcome assessor.


Participants588 eligible patients. 123 excluded after randomisation. 465 enrolled in the study.
Age-range: 15-94 Mean: 33,4
315 enrolled in this part of the study.
The study has 3 subgroups (see Viitanen 1984 A).
In Viitanen 1984 B 327 patients enrolled in study.


InterventionsTreatment group: Tinidazole 500 mg in 100 saline IV preoperativly and 500 mg three time daily for three days.
Placebo group: No treatment.


OutcomesWound infection (Pus from the wounds).
Two patients died, 1 of peritonitis induced by perforation of the appendix, 1 died of cardiac infarction.


NotesTreatment initiated on anaesthetized patient.
No drain treatment.


Risk of bias

ItemAuthors' judgementDescription

Allocation concealment?UnclearD - Not used

Wayand 1982

MethodsRandomised controlled trial. Randomisation by a list of random numbers.
Blinding unclear.


Participants220 eligible patients. 25 excluded after randomisation. 195, 85 males and 110 females enrolled in the study.
Mean-age: 23
Patients who received antibiotics within the previous 3 days before operation, had allergy to antibiotics, were pregnant, and breast-feeding women, patients with kreatinin >3 mg%, and patients who denied consent, were excluded before randomisation.


InterventionsTreatment group: Cefamandol 2 g IV preoperatively and eight-hourly altogether 5 doses.
Placebo group: Not specified 2 g iv preoperatively and eight-hourly altogether 5 doses.


OutcomesWound infection (Not defined).


NotesNo comments on drain treatment


Risk of bias

ItemAuthors' judgementDescription

Allocation concealment?YesA - Adequate

Willis 1976

MethodsRandomised controlled trial, method not stated


Participants105 eligible pt
95 enrolled
10 pts excluded due to prior antibiotic record or failure in randomisation procedure


InterventionsMetronidazole versus placebo as suppository for seven days


Outcomeswound infection
(discharge from the wound)


NotesAll suppositories contain Witepsol 35 and 75


Risk of bias

ItemAuthors' judgementDescription

Allocation concealment?UnclearB - Unclear

Winslow 1983

MethodsRandomised controlled trial. Randomisation by the last number in the patients birthday.
Triple-blinded.


Participants147 eligible patients. 44 excluded after randomisation. 103 enrolled in the study.
Age-range 4-67. Mean 22.
Patients receiving antibiotics 72 hours prior of surgery, had allergy to cephalosporins or penicillin, had impaired renal function and serious underlying disease, were excluded before randomisation


InterventionsTreatment group: Cefoxitin 1 g (children 20-40 mg/kg/dose) IV peroperatively and 6 and 12 hours postoperatively.
Placebo group: Saline regime as above.


OutcomesWound infection (Not defined).
Postoperative intra abdominal abscess (Not defined)
Length of stay in hospital


NotesNo drain treatment.


Risk of bias

ItemAuthors' judgementDescription

Allocation concealment?NoC - Inadequate

 
Characteristics of excluded studies [ordered by study ID]

StudyReason for exclusion

Amgwerd 1981Adequate randomisation, but control group received no treatment, and treatment group received pre-operative and post-operative IM treatment which means inadequate blinding and the results of infection may be biased.

Andersen 1972All patients received post-operative antibiotic.

Badia 1994The treatment group (antibiotics) is compared to a 'control group' receiving a solution with physiological serum.

Bates 1974Randomisation by sealed envelopes. Control group received no treatment, and treatment group received peri-operative topical treatment which means inadequate blinding and the results of infection may be biased.

Birkigt 1989Randomised clinical trial. There are discord in the table of results. The number of patients differ within the same groups.

Birkigt 1991Unknown allocation consealment and odd distribution numbers in the treatment group versus control group.

Bröte 1976Randomisation not stated. Control group received no treatment, and treatment group received postoperative IV treatment which means inadequate blinding and the results of infection may be biased.

Calman 1971Abstract. It has been impossible for the reviewers to get a full study.

Crosfill 1969Randomised controlled trial. Systemic antibiotics were given as supplement to topical treatment to the most seriously ill. The author does not describe which patients that get systemic antibiotics.

Dixon 1984The trial group is patients in elective and emergency operations. No reports on appendicitis exclusively.

Evans 1973Randomisation by toss of a coin. Control group received no treatment, and treatment group received postoperative IM treatment which means inadequate blinding and the results of infection may be biased.

Everson 1977Insufficient subject blinding. Patients receiving post-operative injection three times compared to control group (no treatment)

Feltis 1967Randomisation method not stated. Control group received no treatment, and treatment group received pre-operative, peri-operative and post-operative IV treatment, which means unclear blinding, and the results of infection may be biased.

Gilmore 1973Inadequate allocation consealment

Gilmore 1975Randomisation by af table of random numbers. Unclear which patients received systemic antibiotic treatment within the topical treatment and placebogroup.

Gómez-Alonso 1984Adequate randomisation, but control group received no treatment, and treatment group received pre-operatively and post-operative IM treatment which means inadequate blinding and the results of infection may be biased.

Harahsheh 2002Randomised single blin trial, in which all pts received daily antiseptic dressings with povidone-iodine (10% in alcohol).

Herrera-Garcia 1985Adequate randomisation, but no differentiation between wound infection and intra-abdominal abscess in the result section.

Kling 1985Adequate randomisation, but control group received no treatment, and treatment group received preoperative IV treatment 1-3 hours prior to operation, which means unclear blinding and the results of infection may be biased.

Leigh 1978A study based on prior publised trials, of which we have included one, excluded one (not randomised), and yet another not possible to identify.

Marti 1978Initially three arm study comparing two different antibiotics, which later becomes a two-arm study. No indication of wound infection - only abscesses are described.

McGreal 2002All pts received antibiotic prophylaxis. Clinical question focuses on two different ways of wound closure.

McLean 1983Adequate randomisation. Control group received no treatment, and treatment group received post-operative IV and orally administrated treatment, which means inadequate blinding and the results of infection may be biased.

Okubadejo 1976Randomisation by Fisher´s tabels. Control group received no treatment, and treatment group received post-operative treatment which means inadequate blinding and the results of infection may be biased.

Pietila 1982No statement of placebo/control and any indication of withdrawal of patients.

Pollock 1972The treatment group is composed of abdominal surgery, potentially contaminated operations. No reports on appendicitis exklusively.

Rambo 1972Randomisation adequate. The trial include miscellaneous emergency surgery, of which only one appendectomy was reported.

Tanphiphat 1978Unclear what treatment is given to who post-operatively. In addition, wound lavage is offered all enrolled pt, so it is difficult to establish a clear effect of antibiotic treatment.

Taylor 2000Both comparisons groups received antibiotic treatment

Taylor 2004Both comparisons groups received antibiotic treatment. The protocol seem identical to the Taylor 2000 reference

Walsh 1981Unclear what treatment is given to who post-operative. From table 1, there is a clear distinction between antibiotics and control group. From table 3 it is difficult to establish a clear effect of antibiotic treatment. Therefore we decided to exclude the study.

Willis 1979A summary of metronidazole in the prevention and treatment of anaerobic sepsis, in which appendicitis is a part. Seems identical to prior publication in 1976 (which is included)

 
Comparison 1. Systemic Antibiotics vs Placebo (Clinical)

Outcome or subgroup titleNo. of studiesNo. of participantsStatistical methodEffect size

 1 Wound infection478812Peto Odds Ratio (Peto, Fixed, 95% CI)0.33 [0.29, 0.38]

    1.1 Appendicitis
212343Peto Odds Ratio (Peto, Fixed, 95% CI)0.31 [0.24, 0.42]

    1.2 Simple appendicitis
265317Peto Odds Ratio (Peto, Fixed, 95% CI)0.37 [0.30, 0.46]

    1.3 Complicated appendicitis
241152Peto Odds Ratio (Peto, Fixed, 95% CI)0.28 [0.21, 0.38]

 2 Postoperative intra abdominal abscess164468Peto Odds Ratio (Peto, Fixed, 95% CI)0.43 [0.25, 0.73]

    2.1 Appendicitis
81033Peto Odds Ratio (Peto, Fixed, 95% CI)0.35 [0.13, 0.91]

    2.2 Simple appendicitis
82968Peto Odds Ratio (Peto, Fixed, 95% CI)0.46 [0.23, 0.94]

    2.3 Complicated appendicitis
4467Peto Odds Ratio (Peto, Fixed, 95% CI)0.54 [0.12, 2.43]

 3 Length of stay in hospital81200Mean Difference (IV, Fixed, 95% CI)-1.69 [-1.78, -1.61]

 
Comparison 2. Systemic antibiotics vs placebo (Pathoanatomic)

Outcome or subgroup titleNo. of studiesNo. of participantsStatistical methodEffect size

 1 Wound infection211704Peto Odds Ratio (Peto, Fixed, 95% CI)0.32 [0.22, 0.47]

    1.1 Normal appendix
211555Peto Odds Ratio (Peto, Fixed, 95% CI)0.28 [0.18, 0.44]

    1.2 Perforated appendicitis
6149Peto Odds Ratio (Peto, Fixed, 95% CI)0.47 [0.22, 1.00]

 2 Postoperative intra abdominal abscess3741Peto Odds Ratio (Peto, Fixed, 95% CI)0.28 [0.08, 0.91]

    2.1 Normal appendix
3673Peto Odds Ratio (Peto, Fixed, 95% CI)0.45 [0.10, 1.98]

    2.2 Perforated appendicitis
168Peto Odds Ratio (Peto, Fixed, 95% CI)0.12 [0.02, 0.86]

 
Comparison 3. Topical Antibiotics vs Placebo

Outcome or subgroup titleNo. of studiesNo. of participantsStatistical methodEffect size

 1 Wound infection4679Peto Odds Ratio (Peto, Fixed, 95% CI)0.77 [0.49, 1.23]

    1.1 Appendicitis
2113Peto Odds Ratio (Peto, Fixed, 95% CI)0.65 [0.27, 1.54]

    1.2 Simple appendicitis
2399Peto Odds Ratio (Peto, Fixed, 95% CI)1.30 [0.64, 2.64]

    1.3 Complicated appendicitis
2167Peto Odds Ratio (Peto, Fixed, 95% CI)0.43 [0.18, 1.01]

2 Postoperative intra abdominal abscess00Peto Odds Ratio (Peto, Fixed, 95% CI)Not estimable

   2.1 Appendicitis
00Peto Odds Ratio (Peto, Fixed, 95% CI)Not estimable

   2.2 Simple appendicitis
00Peto Odds Ratio (Peto, Fixed, 95% CI)Not estimable

   2.3 Complicated appendicitis
00Peto Odds Ratio (Peto, Fixed, 95% CI)Not estimable

 3 Lenght of stay in hospital129Mean Difference (IV, Fixed, 95% CI)Not estimable

 
Comparison 4. Pre-operatively administered single agent, single dose Antibiotics vs Placebo

Outcome or subgroup titleNo. of studiesNo. of participantsStatistical methodEffect size

 1 Wound infection112191Peto Odds Ratio (Peto, Fixed, 95% CI)0.34 [0.25, 0.45]

    1.1 Appendicitis
2234Peto Odds Ratio (Peto, Fixed, 95% CI)0.34 [0.14, 0.80]

    1.2 Simple appendicitis
91514Peto Odds Ratio (Peto, Fixed, 95% CI)0.37 [0.25, 0.54]

    1.3 Complicated appendicitis
8443Peto Odds Ratio (Peto, Fixed, 95% CI)0.29 [0.18, 0.47]

 2 Postoperative intra abdominal abscess2446Peto Odds Ratio (Peto, Fixed, 95% CI)0.34 [0.05, 2.45]

   2.1 Appendicitis
00Peto Odds Ratio (Peto, Fixed, 95% CI)Not estimable

    2.2 Simple appendicitis
2382Peto Odds Ratio (Peto, Fixed, 95% CI)0.34 [0.05, 2.45]

    2.3 Complicated appendicitis
164Peto Odds Ratio (Peto, Fixed, 95% CI)Not estimable

 3 Length of stay in hospital1121Mean Difference (IV, Fixed, 95% CI)0.40 [-0.01, 0.81]

 
Comparison 5. Pre-operatively administered multiple agent, single dose Antibiotics vs Placebo

Outcome or subgroup titleNo. of studiesNo. of participantsStatistical methodEffect size

 1 Wound infection2215Peto Odds Ratio (Peto, Fixed, 95% CI)0.14 [0.05, 0.39]

    1.1 Appendicitis
1133Peto Odds Ratio (Peto, Fixed, 95% CI)0.12 [0.02, 0.61]

    1.2 Simple appendicitis
182Peto Odds Ratio (Peto, Fixed, 95% CI)0.16 [0.04, 0.59]

   1.3 Complicated appendicitis
00Peto Odds Ratio (Peto, Fixed, 95% CI)Not estimable

2 Postoperative intra abdominal abscess00Peto Odds Ratio (Peto, Fixed, 95% CI)Not estimable

   2.1 Appendicitis
00Peto Odds Ratio (Peto, Fixed, 95% CI)Not estimable

   2.2 Simple appendicitis
00Peto Odds Ratio (Peto, Fixed, 95% CI)Not estimable

   2.3 Complicated appendicitis
00Peto Odds Ratio (Peto, Fixed, 95% CI)Not estimable

3 Length of stay in hospital00Mean Difference (IV, Fixed, 95% CI)Not estimable

 
Comparison 6. Per-operatively administered single agent, single dose Antibiotics vs Placebo

Outcome or subgroup titleNo. of studiesNo. of participantsStatistical methodEffect size

 1 Wound infection123358Peto Odds Ratio (Peto, Fixed, 95% CI)0.43 [0.34, 0.55]

    1.1 Appendicitis
6585Peto Odds Ratio (Peto, Fixed, 95% CI)0.37 [0.22, 0.60]

    1.2 Simple appendicitis
62347Peto Odds Ratio (Peto, Fixed, 95% CI)0.52 [0.37, 0.73]

    1.3 Complicated appendicitis
5426Peto Odds Ratio (Peto, Fixed, 95% CI)0.35 [0.21, 0.58]

 2 Postoperative intra abdominal abscess32115Peto Odds Ratio (Peto, Fixed, 95% CI)0.67 [0.32, 1.42]

    2.1 Appendicitis
2380Peto Odds Ratio (Peto, Fixed, 95% CI)0.69 [0.12, 3.99]

    2.2 Simple appendicitis
11554Peto Odds Ratio (Peto, Fixed, 95% CI)0.74 [0.31, 1.79]

    2.3 Complicated appendicitis
1181Peto Odds Ratio (Peto, Fixed, 95% CI)0.32 [0.03, 3.29]

 3 Length of stay in hospital2209Mean Difference (IV, Fixed, 95% CI)-0.80 [-1.34, -0.26]

 
Comparison 7. Per-operatively administered multiple agent, single dose Antibiotics vs Placebo

Outcome or subgroup titleNo. of studiesNo. of participantsStatistical methodEffect size

 1 Wound infection4216Peto Odds Ratio (Peto, Fixed, 95% CI)0.23 [0.12, 0.45]

    1.1 Appendicitis
3161Peto Odds Ratio (Peto, Fixed, 95% CI)0.24 [0.11, 0.52]

    1.2 Simple appendicitis
143Peto Odds Ratio (Peto, Fixed, 95% CI)0.19 [0.04, 0.89]

    1.3 Complicated appendicitis
112Peto Odds Ratio (Peto, Fixed, 95% CI)0.25 [0.03, 2.52]

2 Postoperative intra abdominal abscess00Peto Odds Ratio (Peto, Fixed, 95% CI)Not estimable

   2.1 Appendicitis
00Peto Odds Ratio (Peto, Fixed, 95% CI)Not estimable

   2.2 Simple appendicitis
00Peto Odds Ratio (Peto, Fixed, 95% CI)Not estimable

   2.3 Complicated appendicitis
00Peto Odds Ratio (Peto, Fixed, 95% CI)Not estimable

3 Length of stay in hospital00Mean Difference (IV, Fixed, 95% CI)Not estimable

 
Comparison 8. Operatively single agent and post-operatively single agent, single dose Antibiotics vs placebo

Outcome or subgroup titleNo. of studiesNo. of participantsStatistical methodEffect size

 1 Wound infection3256Peto Odds Ratio (Peto, Fixed, 95% CI)0.16 [0.07, 0.36]

    1.1 Appendicitis
3256Peto Odds Ratio (Peto, Fixed, 95% CI)0.16 [0.07, 0.36]

   1.2 Simple appendicitis
00Peto Odds Ratio (Peto, Fixed, 95% CI)Not estimable

   1.3 Complicated appendicitis
00Peto Odds Ratio (Peto, Fixed, 95% CI)Not estimable

 2 Postoperative intra abdominal abscess2161Peto Odds Ratio (Peto, Fixed, 95% CI)0.12 [0.02, 0.89]

    2.1 Appendicitis
2161Peto Odds Ratio (Peto, Fixed, 95% CI)0.12 [0.02, 0.89]

   2.2 Simple appendicitis
00Peto Odds Ratio (Peto, Fixed, 95% CI)Not estimable

   2.3 Complicated appendicitis
00Peto Odds Ratio (Peto, Fixed, 95% CI)Not estimable

3 Length of stay in hospital00Mean Difference (IV, Fixed, 95% CI)Not estimable

 
Comparison 9. Operatively single agent and post-operatively single agent, multiple dose Antibiotic vs Placebo

Outcome or subgroup titleNo. of studiesNo. of participantsStatistical methodEffect size

 1 Wound infection142097Peto Odds Ratio (Peto, Fixed, 95% CI)0.46 [0.35, 0.60]

    1.1 Appendicitis
81039Peto Odds Ratio (Peto, Fixed, 95% CI)0.45 [0.30, 0.68]

    1.2 Simple appendicitis
6875Peto Odds Ratio (Peto, Fixed, 95% CI)0.46 [0.30, 0.70]

    1.3 Complicated appendicitis
6183Peto Odds Ratio (Peto, Fixed, 95% CI)0.47 [0.24, 0.90]

 2 Postoperative intra abdominal abscess3448Peto Odds Ratio (Peto, Fixed, 95% CI)0.14 [0.01, 1.30]

    2.1 Appendicitis
2269Peto Odds Ratio (Peto, Fixed, 95% CI)0.13 [0.01, 2.08]

    2.2 Simple appendicitis
1179Peto Odds Ratio (Peto, Fixed, 95% CI)0.15 [0.00, 7.38]

   2.3 Complicated appendicitis
00Peto Odds Ratio (Peto, Fixed, 95% CI)Not estimable

 3 Length of stay in hospital4434Mean Difference (IV, Fixed, 95% CI)-1.0 [-1.81, -0.19]

 
Comparison 10. Operatively multiple agent and post operatively multiple agent, single dose Antibiotic vs Placebo

Outcome or subgroup titleNo. of studiesNo. of participantsStatistical methodEffect size

1 Wound infection00Peto Odds Ratio (Peto, Fixed, 95% CI)Not estimable

   1.1 Appendicitis
00Peto Odds Ratio (Peto, Fixed, 95% CI)Not estimable

   1.2 Simple appendicitis
00Peto Odds Ratio (Peto, Fixed, 95% CI)Not estimable

   1.3 Complicated appendicitis
00Peto Odds Ratio (Peto, Fixed, 95% CI)Not estimable

2 Postoperative intra abdominal absces00Peto Odds Ratio (Peto, Fixed, 95% CI)Not estimable

   2.1 Appendicitis
00Peto Odds Ratio (Peto, Fixed, 95% CI)Not estimable

   2.2 Simple appendicitis
00Peto Odds Ratio (Peto, Fixed, 95% CI)Not estimable

   2.3 Complicated appendicitis
00Peto Odds Ratio (Peto, Fixed, 95% CI)Not estimable

3 Length of stay in hospital00Mean Difference (IV, Fixed, 95% CI)Not estimable

 
Comparison 11. Operatively multiple agent and post-operatively multiple agent, multiple dose Antibiotics vs placebo

Outcome or subgroup titleNo. of studiesNo. of participantsStatistical methodEffect size

 1 Wound infection6851Peto Odds Ratio (Peto, Fixed, 95% CI)0.18 [0.11, 0.27]

    1.1 Appendicitis
1200Peto Odds Ratio (Peto, Fixed, 95% CI)0.25 [0.10, 0.62]

    1.2 Simple appendicitis
4562Peto Odds Ratio (Peto, Fixed, 95% CI)0.20 [0.11, 0.35]

    1.3 Complicated appendicitis
589Peto Odds Ratio (Peto, Fixed, 95% CI)0.08 [0.03, 0.22]

 2 Postoperative intra abdominal abscess3488Peto Odds Ratio (Peto, Fixed, 95% CI)0.38 [0.05, 2.72]

    2.1 Appendicitis
1133Peto Odds Ratio (Peto, Fixed, 95% CI)0.98 [0.06, 15.92]

    2.2 Simple appendicitis
2355Peto Odds Ratio (Peto, Fixed, 95% CI)0.15 [0.01, 2.38]

   2.3 Complicated appendicitis
00Peto Odds Ratio (Peto, Fixed, 95% CI)Not estimable

 3 Length of stay in hospital190Mean Difference (IV, Fixed, 95% CI)Not estimable

 
Comparison 12. Systemic antibiotics vs Placebo in children

Outcome or subgroup titleNo. of studiesNo. of participantsStatistical methodEffect size

 1 Wound infection71090Peto Odds Ratio (Peto, Fixed, 95% CI)0.64 [0.37, 1.10]

    1.1 Appendicitis
1133Peto Odds Ratio (Peto, Fixed, 95% CI)0.98 [0.39, 2.44]

    1.2 Simple appendicitis
6704Peto Odds Ratio (Peto, Fixed, 95% CI)0.92 [0.33, 2.57]

    1.3 Complicated appendicitis
3253Peto Odds Ratio (Peto, Fixed, 95% CI)0.31 [0.12, 0.77]

 2 Postoperative intra abdominal abscess61003Peto Odds Ratio (Peto, Fixed, 95% CI)0.29 [0.10, 0.83]

    2.1 Appendicitis
1133Peto Odds Ratio (Peto, Fixed, 95% CI)0.25 [0.05, 1.26]

    2.2 Simple appendicitis
5648Peto Odds Ratio (Peto, Fixed, 95% CI)0.14 [0.02, 0.98]

    2.3 Complicated appendicitis
2222Peto Odds Ratio (Peto, Fixed, 95% CI)0.78 [0.11, 5.70]

3 Length of stay in hospital00Mean Difference (IV, Fixed, 95% CI)Not estimable

 
Comparison 13. Operatively single agent and post-operatively single agent, multiple dose Antibiotic vs Placebo in children

Outcome or subgroup titleNo. of studiesNo. of participantsStatistical methodEffect size

 1 Wound infection5953Peto Odds Ratio (Peto, Fixed, 95% CI)0.52 [0.29, 0.93]

    1.1 Appendicitis
1133Peto Odds Ratio (Peto, Fixed, 95% CI)0.98 [0.39, 2.44]

    1.2 Simple appendicitis
4598Peto Odds Ratio (Peto, Fixed, 95% CI)0.85 [0.26, 2.80]

    1.3 Complicated appendicitis
2222Peto Odds Ratio (Peto, Fixed, 95% CI)0.16 [0.06, 0.44]

 2 Postoperative intra abdominal abscess6955Peto Odds Ratio (Peto, Fixed, 95% CI)0.29 [0.10, 0.83]

    2.1 Appendicitis
1133Peto Odds Ratio (Peto, Fixed, 95% CI)0.25 [0.05, 1.26]

    2.2 Simple appendicitis
5600Peto Odds Ratio (Peto, Fixed, 95% CI)0.14 [0.02, 0.98]

    2.3 Complicated appendicitis
2222Peto Odds Ratio (Peto, Fixed, 95% CI)0.78 [0.11, 5.70]

3 Length of stay in hospital00Mean Difference (IV, Fixed, 95% CI)Not estimable

 
Comparison 14. Operatively multiple agent and post-operatively multiple agent, multiple dose Antibiotics vs placebo, children

Outcome or subgroup titleNo. of studiesNo. of participantsStatistical methodEffect size

 1 Wound infection150Peto Odds Ratio (Peto, Fixed, 95% CI)Not estimable

   1.1 Appendicitis
00Peto Odds Ratio (Peto, Fixed, 95% CI)Not estimable

    1.2 Simple appendicitis
150Peto Odds Ratio (Peto, Fixed, 95% CI)Not estimable

   1.3 Complicated appendicitis
00Peto Odds Ratio (Peto, Fixed, 95% CI)Not estimable

 2 Postoperative intra abdominal abscess150Peto Odds Ratio (Peto, Fixed, 95% CI)Not estimable

   2.1 Appendicitis
00Peto Odds Ratio (Peto, Fixed, 95% CI)Not estimable

    2.2 Simple appendicitis
150Peto Odds Ratio (Peto, Fixed, 95% CI)Not estimable

   2.3 Complicated appendicitis
00Peto Odds Ratio (Peto, Fixed, 95% CI)Not estimable

3 Length of stay in hospital00Mean Difference (IV, Fixed, 95% CI)Not estimable