Technical, ergonomic and cognitive learning methodology in transumbilical single‐port laparoscopic hysterectomy

We introduced learning curves on a detailed step protocol and ergonomic aspect to determine key surgical points in transumbilical single‐port laparoscopic hysterectomy (TSPLH) and to popularize both technical and cognitive methodology on laparoendoscopic single‐site surgery (LESS).


| INTRODUC TI ON
Hysterectomy is a commonly performed gynecologic surgical procedure and is expected to be mastered by obstetricians/gynecologists (OB/GYN).Out of the four methods of abdominal, vaginal, laparoscopic, or robotic approaches, total laparoscopic hysterectomy (TLH) is the only approach that requires the highest degree of laparoscopic surgical skills.The entire procedure is performed laparoscopically except for the removal of the uterus. 1 Recently, laparoendoscopic single-site surgery (LESS) has gained popularity as a minimally invasive surgery option for treating benign gynecologic diseases.This procedure is performed through a single multiport device with a small incision in the skin. 2 On the other hand, transumbilical single-port laparoscopic hysterectomy (TSPLH) offers the benefits of a virtually scarless procedure, faster recovery time, better cosmetic results, and reduced risk of wound infection. 3However, the challenges in TSPLH, such as the access point, loss of triangulation, clashing between instruments, limited movement plane and number of active instruments, 4 increase the difficulty of the procedure and may prolong the operative time. 5In TSPLH, all three laparoscopic apparatus ports enter the abdominal cavity through the same incision, causing restrictions in the operating field and making it challenging to work from two directions as in traditional multiport laparoscopic surgery (MPS).This requires the surgeon to have significant experience with laparoscopic operations to overcome these difficulties.
The Accreditation Council for Graduate Medical Education (ACGME) highlights medical knowledge, communication skills, practice-based learning and improvement, and systems-based practice as the key components in resident training. 6However, novice surgeons face the challenge of reduced clinical experience and increasing surgical complexity. 7Studies show that only 20%-28% of graduating residents feel prepared to perform a vaginal hysterectomy independently, while 46%-58% can perform an abdominal hysterectomy, and only 22% can perform a laparoscopic hysterectomy, 8,9 highlighting the need for training in LH and TSPLH.There are programs designed to improve surgical skills, 10 including simulation models, 11 proficiency-based training, or video-based coaching, that offer novice gynecologic surgeons an opportunity to practice laparoscopic hysterectomy before actual surgery.However, detailed surgical elements, obstacles, and countermeasures can only be learned through actual surgical experience.Our study focuses on the self-guided learning of educators during TSPLH procedures, analyzing detailed surgical elements, obstacles, and countermeasures, as well as ergonomic points, to understand the cognitive and technical aspects of the ideal surgical education learning curve.The goal is to establish a methodological education for TSPLH and LESS, to benefit more surgeons.

| Patient data collection and the inclusion or exclusion criteria
In this retrospective study, 87 patients with benign gynecological conditions were selected for TSPLH surgery by Surgeon A at the Shanghai General Hospital affiliated with Shanghai Jiao Tong University School of Medicine between January 2021 and April 2022 (Table S1).These patients gave their informed consent for the surgical procedure and the use of their medical records for research purposes.The study was approved by the institutional review board (IRB) of Shanghai General Hospital, Shanghai Jiao Tong University School of Medicine (2022KY061).Exclusions from the LESS procedure were similar to those for MPS, including conditions such as cardiovascular, respiratory, urinary, nervous system failure, or other serious adhesions.

| Surgical instruments
The surgical instruments used in the procedure included a single-

| Statistical methods
Data were presented as mean ± standard deviation with 95% confidence intervals (95% CI).Statistical significance was set at P < 0.05.Demographic variables were compared between groups using χ 2 or Fisher exact test.Perioperative data were analyzed using Student's t-test or single-factor ANOVA for continuous variables, and Mann-Whitney test for non-parametric variables.All analyses was conducted using SPSS Statistical Software version 25.0 (IBM Corp., Armonk, NY, USA) and graphed using GraphPad Prism Software version 9.0 (GraphPad Software, San Diego, CA, USA).

| Surgical approach
In traditional laparoscopic surgery, instruments are inserted through two cannulas: one 5-12 mm channel (No. 2) and one 3-5 mm channel (No. 3 or 4) on the left side of the video laparoscope, and another 5-12 mm channel (No. 1) on the right side of the single-hole cannula trocar device.This is shown schematically in Figure 1a.During the procedure, bipolar graspers or monopolar scissors are usually held by the main surgeon's right hand and placed through channel 2, while dissecting forceps are held by the left hand and placed through channel 3 or 4. The configuration of instruments may be adjusted based on the situation during surgery (Figure 1b).This approach eliminates the need for the surgeon to cross over the assistant's hand, reducing discomfort during the procedure.

| Learning stage
Surgeon A had over a decade of experience in MPS and was wellversed in the procedure protocol and pelvic anatomy.For the LESS procedure, conventional straight instruments were utilized instead of long length instruments, based on the findings from meta-analysis and randomized controlled trial research that articulated or prebending instruments are not practical. 12The learning process was divided into three phases: 10 cases in the first phase consisting of uterine leiomyoma (four cases), adenomyosis (three cases), and uterine prolapse (three cases).The second phase had 13 cases, including uterine leiomyoma (five cases), adenomyosis (four cases), and uterine prolapse (four cases).The third phase had 27 cases, including uterine leiomyoma (19 cases) and adenomyosis (eight cases).Another 32 cases with near-normal uterine volumes were classified as the fourth group, including 16 cases of uterine prolapse, four cases of cervical carcinoma in situ, five cases of high-grade squamous intraepithelial lesion (HSIL), and seven cases of endometrial hyperplasia with atypia.In cases of uterine prolapse, operative time was calculated only within hysterectomies and did not include the time for repairing the anterior and posterior vaginal walls.No significant differences were found among the four groups for patient age (year), body mass index (BMI, calculated as weight in kilograms divided by the square of height in meters), incision length at closure (cm), out-ofbed activity time (h), anal exhaust time (h), or stay of hospitalization (days) (P > 0.05).There was a noticeable significant difference in pre-and postoperative hemoglobin (Hb, g/L) as well as Hb drop (g/L) (Figure 1d), estimated blood loss (mL) (Figure 1e), uterine volume (calculated by gestational weeks), operative time (min) (Figure 1f), and fluid infusion (L) (P ≤ 0.05) (Table S2).

| Ergonomic aspect
We introduced ergonomic aspects of the main surgeon's corporal posture, muscular tension, traction countertraction, angle, and movements as essential ergonomic elements in our previous paper, "Ergonomic hand-on performance on gynecological laparoendoscopic single-site surgery".In TSPLH, the main surgeon should also follow the special ergonomic skills: 1.To shorten the distance from the transumbilical incision to the target tissue, we take advantage of the soft and retractable multichannel porter.We hold the instrument and move it forward with appropriate force and tension so that we can grasp the target tissue.3. The location and orientation of the shoulders, arms, wrist, and fingers were coordinated to apply grasping techniques, including grasping, lifting, separation, coagulation, cutting, and suturing (Figure 2b, Figure S1b).4. To accomplish perfect tissue handling and avoid injury to adjacent structures, flexion and extension of the wrist and fingers were adjusted to obtain good power and angle with instruments and achieve hand-eye coordination (Figure 2c, Figure S1c).

| Detailed technical steps in TSPLH
We standardized the surgical elements, obstacles, and countermeasures for hysterectomies by breaking down the procedure into individual steps.The patients underwent general anesthesia and were positioned on their back.The laparoscopic instruments were inserted into the peritoneal cavity through transumbilical incisions of 2-3 cm using a single-hole, multi-channel port device.The primary surgeon stood on the left side of the patient, while the assistant holding the video laparoscope was on the right side, and the second assistant held the uterine manipulator.This approach differed ergonomically from conventional transperitoneal laparoscopic surgery, with identical steps being followed after the initial intra-abdominal survey.The following description outlines the specific steps and ergonomic methods for TSPLH, and highlights the key learning points of this procedure.

Ovarian ligament and fallopian tube division
The division of the ovarian ligament and fallopian tube is similar to the operation performed during MPS.In LESS, the fallopian tube is clamped with the left hand by separating forceps, and the infundibulopelvic ligament is cauterized and cut with the bipolar coagulation and monopolar scissors.

Uterus vascular control and colpotomy
The lateral uterine artery and vessels were first fully exposed (Figure 3a).Then, electrocoagulation was performed using bipolar forceps (Figure 3b) and cutting was done using monopolar scissors (Figure 3c) to cut off the uterine artery and vessels at the edge of the cup (Figure 3d).The vaginal manipulator could be adjusted left or right to control the anatomy and mobility of the uterus while working on the corresponding uterine artery and vessels.Next, the sacral and cardinal ligaments were coagulated (Figure 3e) and cut off (Figure 3f) inside the ureter.The cervicovaginal part was then cut in a circular incision along the edge of the manipulator's cup using a unipolar hook.A unipolar hook was used to save space or, when cutting the left edge of the vaginal margin, dissecting forceps were used to press the colon to prevent overheating of the unipolar hook and injury to the intestine.Finally, the uterus was dissociated, fragmented, and removed through the vagina.

Laparoscopic vaginal stump closure
The vaginal stump after the hysterectomy can be sutured using either transvaginal or laparoscopic continuous barbed sutures with size 0/0 "V-lock".In cases of uterine prolapse, transvaginal suture is preferred due to its shorter operation time.However, suturing the vaginal cuff under the LESS method can be technically challenging due to the limited surgical space.To overcome this, the retroperitoneum of the bladder should be pushed down to provide enough space for suturing, displaying approximately 2-3 cm of the mucosa of the cervicovaginal part.Routinely, a needle was inserted into the posterior vaginal stump (Figure 4a) and then out from the lower end of the anterior vaginal wall (Figure 4b-e suturing, it could be applied in a routine manner.This allows for enough vaginal tissue to be sutured and closed, avoiding injury to the nearby uterine artery (Video S1).

Vaginal manipulator control
There will be obvious obstructions when dealing with the ligament vessels of the lateral ovary and the uterine vessels, and the surgical instruments on the opposite side will be blocked since the large uterine body extends to both sides.

Handling bleeding
During TSPLH, the coagulation and cutting of the uterine artery was a difficult task that could result in accidental injury and uncontrolled bleeding.In cases where the uterus had a large volume of 17-20 gestational weeks due to leiomyoma or adenomyosis, excessive coagulation could cause damage to the nearby ureter and increase the risk of thermal injury; normally, the average distance between the ureter and cervix is 2 cm in the pelvis, but in 3.2% of the population, it would be close to 0.5 cm. 13 In such cases, Surgeon A successfully stopped the bleeding by quickly aspirating blood, clamping the bleeding site with forceps, and suturing the tissue.The assistant was instructed to hold the uterine manipulator while the main surgeon coagulated and cut the uterus and parametrium in steps to prevent retraction bleeding.If the assistant adjusts the direction of the uterine manipulator with excessive magnitude or force, vascular retraction occurs at the preserved end (Figure 3d), resulting in bleeding.In conclusion, in cases where the uterus had large leiomyomas or adenomyosis, it was important to proceed with caution and be aware of the potential for bleeding due to tortuous and hidden parametrial blood vessels.

Dealing with a large uterus
The large uterus filled the pelvis and lower abdominal cavity, and the field of view under the microscope and the operating space were significantly reduced.Solution: 1.The skin incision length could be enlarged by 0.5-1 cm to ensure that the instrument had sufficient operating space to provide an adequate working room.
2. Since the channels in the port are soft, the position of the instrument is adjusted to the video-laparoscope to obtain the best operating angle when instruments interfere with each other.The laparoscope holder assistant needs to skilfully use the advantages of the 30° mirror to display the side and rear of large uterus structures through the rotation of the lens angle.

| Systematization of feedback
Evaluating technical competency in surgical procedures is crucial for ensuring optimal learning outcomes.Self-assessment of surgical skills provides an opportunity for personal reflection and development of future learning plans.To assess the influence of technical and cognitive factors in total supracervical posterior laparoscopic hysterectomy (TSPLH), we used the performance of Surgeon A and applied procedure-specific rating scales such as Objective Structured Assessment of Technical Skills (OSATS) 14 or Global Operative Assessment of Laparoscopic Skills (GOALS). 15,16We identified four key steps in TSPLH: ligament mobilization, release of adnexa from the uterus, division of uterine vessels, and vaginal cuff suturing.Technical elements that are evaluated include depth perception, visuospatial abilities, hand-eye coordination, tissue handling, and muscle energy sources.The proficiency is divided into three levels-laborious, improved, and mastery-corresponding to three learning stages.As the learning process progresses, Surgeon A's dexterity and efficiency improve, leading to increased confidence in their cognitive abilities.

| DISCUSS ION
In TSPLH, the narrow entrance of the LESS port system causes instrument interference, hindering the surgeon's performance.The competence of the trainee is usually evaluated by measuring the surgical volume in line with the Accreditation Council for Graduate Medical Education (ACGME) using the Resident Case Log System 17 or female pelvic medicine and reconstructive surgery (FPMRS). 18veiro-Fuentes et al. 19 divided the learning period based on the surgeon's experience, with the first 75 hysterectomies being the "novice period," the next 75 being the "intermediate period," and the subsequent 86 being the "routine period."Some researchers believe that 75% of surgical procedures depend on cognitive skills, while only 25% are related to technical aspects. 20Of course, adequate training is an essential factor for surgical improvement, and highvolume surgeons tend to have better results in performing hysterectomies than those with lower volumes. 21e International Ergonomics Association defines ergonomics as the study of optimizing human well-being and system performance through the application of principles and theories on human-system interactions. 22Our research focuses on ergonomic techniques related to surgeons' muscle and joint movements during surgery.
Our findings indicate that the LESS approach results in less wrist flexion, increased range of motion, and heightened muscle activity in the trapezius and forearm extensor muscles. 23The LESS approach entails a greater level of muscular activity in the trapezius and forearm extensor muscles 5 and also reduces hyperflexion by over 30°, improving wrist position and instrument performance. 24Surgeon A showed improvement in ergonomic skills, including better coordination and tissue handling, as the study progressed.In a debriefing session, the surgeon reflected on findings, decision-making, and strategies for improvement.The present study highlights key aspects of LESS-generated movements in the shoulder, arm, and wrist, muscle power, and flexibility that are crucial for optimal instrument triangulation and visualization during laparoscopic surgery.These techniques, not widely mentioned in previous studies, can greatly benefit the resident or junior surgeon.
The size of the uterus, presence of multiple myomas, prior abdominal surgeries, and obesity were once considered relative contraindications for laparoscopic surgery, 25 but a retrospective review of 5160 cases showed that a technically skilled surgeon can perform a successful laparoscopic hysterectomy, even in cases with a median uterine weight of 201.5 g and median operative time of 102 min. 22In complicated cases, gynecologists can switch to conventional laparoscopy by adding extra trocars, reducing risks.Proper preoperative case selection, including a thorough gynecological examination and medical history review, is crucial to minimize perioperative risks, particularly for patients with severe pelvic adhesions, prior myomectomy, cesarean sections, and endometriosis. 26ditionally, it is important to be cautious during operations to prevent complications.Previous studies have reported ureteral injury rates of 0.78%-1.8% in laparoscopic hysterectomies, 27,28 with a higher risk of bladder and ureter damage during the first 30 LESS procedures. 29,30The risk of urinary tract injury (10% higher) 31 may be higher in cases of distorted tissue planes from adhesions, lower uterine segment fibroids, or endometriosis. 32However, experienced surgeons can minimize the risk of complications compared with other surgical routes. 33though hysterectomy through vaginal natural orifice transluminal endoscopic surgery (vNOTES) has the advantage of no abdominal wall incisions compared with single-port hysterectomy, 34 factors such as increased technical difficulty and limited mobility of the uterus can limit its practicality.Conversely, laparoscopic hysterectomy offers several advantages over robotic-assisted hysterectomy, including lower cost, shorter surgical time, fewer ports needed, and similar outcomes.This procedure can also be performed in any hospital. 35search has shown that LESS surgery results in higher prefrontal beta power during suturing, compared with other methods. 36 assess the ergonomic stress on surgeons, various methods have been employed in the literature, including surface electromyography (sEMG) to measure muscle activity; 37 hand function models for analyzing tendon and joint forces, electromyographic (EMG) activity; 38 and assessments of posture, activity, tools, and handling, as well as eye tracking to evaluate cognitive variations in surgical scenarios. 39In addition, certain studies in simulated settings in artificial intelligence using gaze-based measures depending on eye tracking to evaluate a clinician's eye movements were sensitive to detect operator cognitive variations in surgical scenarios. 3Jose et al. even monitored EEG power spectra during LESS surgery to measure mental workload in surgeons.In the future, virtual reality tools could be used to evaluate an individual surgeon's cognitive demands, learning curve, and surgical skill levels.

| CON CLUS ION
The present study aimed to identify key surgical points in TSPLH and improve the learning process for surgeons.The study was retrospective, limited to one institution and based on the experience of a selected group of surgeons, which may affect its generalizability.
Future studies should involve multiple centers to broaden the scope and reach a consensus on the methodology.

2 .
Use strength and expansion of the shoulders, maintain an angle of approach 90°-120° between the elbows and arms of the main F I G U R E 1 Surgical approach and learning stage.(a) Single-hole multichannel cannula trocar device with two 5-12 mm (channels 1 and 2) and two 3-5 mm (channels 3 and 4) channel approach systems.(b) The instruments (channels 2, 3, and 4) are all placed on the left side of the video laparoscope (channel 1).The first surgeon's right hand (red arrow) did not need to ride over the assistant doctor's hand (yellow arrow).(c) Model of the uterus under laparoendoscopic single-site surgery (LESS).Instruments: 30° video-laparoscope (yellow), dissecting forceps (blue), bipolar grasper (orange), monopolar scissors (green), channel (purple).Hemoglobin (Hb) drop (g/L).(d) Estimated blood loss (mL).(e) Operative time (min).(f) Among different learning periods in laparoscopic hysterectomy.*P < 0.05.surgeon.Apply abduction and adduction motions of shoulders and arms.This corporal posture promoted cross-triangle angle formation under LESS and maintained good laparoscopic spatial sensation (Figure 2a, Figure S1a).

5 .
Apply flexibility, depth perception, continuous forces, and repetition with muscular effort on the arm, wrist, and fingers.Expert coordination between the dominant hand (DH) and the nondominant hand (NDH) (Figure2d, FigureS1d).
Creating a safe and clear surgical plane is crucial for the division of the round and broad ligament, bladder flap, and retroperitoneal space.The retroperitoneum is incised along the cutting end of the round ligament, exposing the anterior-lateral-posterior retroperitoneal space.Unlike conventional TLH, the assistant surgeon cannot adjust the position of the uterus by placing another instrument through the port, which would cause limited space crowding.Instead, the second assistant surgeon helps to adjust the position F I G U R E 2 Ergonomic power on corporal posture.(a) Expansion of the shoulder muscle maintains an angle of approaching 120° between the elbows and arms.(b) Coordination with shoulders, arms, wrist, and fingers.(c) Adjust flexion and extension of the wrist and fingers.(d) Apply flexibility, depth perception, continuous forces, and repetition with muscular effort on the arm, wrist, and fingers between the dominant hand (DH) and the nondominant hand (NDH).s, shoulder; e, elbows; a, arms; w, wrist; f, finger. of the uterus by firmly supporting the uterine cup and pushing the vaginal manipulator.The main surgeon then dissects the bladder to display the uterovesical fold using monopolar scissors.The vaginal manipulator is used to increase the distance between the ureter and cervix to prevent injury.
).As the needle holder and the dissecting forceps nearly became parallel, it was difficult to form triangles or vertical stitching angles.The main surgeon usually failed to grasp the anterior vaginal wall with dissecting forceps by the left hand and at the same time insert the needle with the right hand, resulting in difficulty in exiting the anterior vaginal stump, especially on both ends of the vaginal stump, once the needle was entered into one edge of the posterior vaginal stump.Surgeon A developed a new technique to suture the vaginal stump by first suturing the posterior vaginal stump followed by the anterior.The first stitch is inserted at a 90° angle into the posterior vaginal stump as usual (Figure 4f,g).After pushing the needle out, it is inserted again from the upper end of the anterior vaginal wall and then pushed out (Figure 4h-l).When conducting the second F I G U R E 3 Uterine vascular control production.(a, b) Electrocoagulation of the uterine artery and vessels with bipolar forceps.(c, d) The uterine artery and vessels were cut off with monopolar scissors at the edge of the cup.(d) Sometimes vascular retraction occurs at the preserved end (green arrow).(e, f) The sacral and cardinal ligaments were correspondingly cut off: (e) inside the ureter; (f) with coagulation.

1 .
The proper use of the vaginal manipulator is crucial for successful completion of the procedure.By maintaining a continuous upward force with the manipulator's cup against the cervicovaginal part, the loose tissue between the bladder and cervicovaginal part can be easily displaced.This allows for precise cutting of the uterine artery and surrounding parametrium tissue along the edge of the cup.However, if the assistant fails to keep the cup tightly fit against the cervicovaginal part, creating a gap in the parametrium tissue, the uterine artery may not be fully coagulated, leading to the risk of bleeding at the stump after disconnection.2. The assistant must ensure a tight fit of the cup of the vaginal manipulator with the cervicovaginal part to avoid interspace and F I G U R E 4 Suturing vaginal stump.(a-d) The needle was inserted into the posterior vaginal stump and out from the lower end of the anterior vaginal wall.(e-g) The first stitch was injected into and pushed out from the posterior vaginal stump.(h-l) The needle was inserted again from the upper end of the anterior vaginal wall and then pushed out.ensure complete coagulation of the uterine artery and parametrial tissue.The large uterus was pushed as far as possible above the pelvic entrance by lifting the uterine manipulator to gain enough space for processing parametrial tissue.
AUTH O R CO NTR I B UTI O N S YY contributed to conceptualization, data curation, formal analysis, funding acquisition, investigation, methodology, project administration, supervision, and writing of the original draft, review and editing.YY contributed to conceptualization and resources.SG contributed to project administration, supervision and visualization, and WLS, WL and SFW contributed to project administration and writing review and editing.All authors contributed to the article and approved the submitted version.