• endoscopic modified Lothrop procedure;
  • frontal sinusotomy;
  • endoscopic sinus surgery;
  • patency;
  • outcomes;
  • risk factors


The purpose of this level 4, retrospective cohort study was to detail the outcomes of primary, revision, and endoscopic modified Lothrop procedure (EMLP) (Draf III) frontal sinus surgery and evaluate whether risk factors would help determine which patients would benefit from which procedures.


The study used a retrospective chart review. Endoscopic assessment of frontal ostium patency and patient reported symptoms were prospectively collected on patients who underwent frontal sinusotomy between January 2003 and December 2009. High-risk cohorts were studied to assess their response to standard endoscopic sinus surgery (ESS) compared with EMLP.


A total of 339 patients who met the inclusion and exclusion criteria underwent either primary or revision endoscopic frontal sinus surgery. The average ± standard deviation (SD) length of follow-up was 20.8 ± 18.7 (95% confidence interval [CI], 18.0–22.9) months. Postsurgical recurrence of disease with persistence of symptoms requiring an EMLP occurred in 9 patients in the primary group and 38 in the revision group. The highest risk groups for failure of standard frontal sinusotomy were patients with nasal polyps, asthma, Lund-Mackay score >16, and frontal ostium size <4 mm (relative risk = 9.9, p < 0.0001).


Patients with underlying asthma and polyposis as well as narrow frontal ostia and extensive radiological disease have a high failure rate from standard endoscopic frontal sinusotomy. In this patient group consideration should be given to offering the patient a primary EMLP procedure, which has excellent success rates with low risks and low morbidity.