Locum Tenens and Pediatric Surgery: A Position Statement and Practice Guidelines From the American Pediatric Surgical Association (APSA).

The American Pediatric Surgical Association (APSA) Practice Committee endorsed by the Board of Governors presents a Position Statement on the role of locum tenens in the practice of pediatric surgery. The Practice Committee also presents a set of guidelines for locum tenens practice. These recommendations highlight safe practice and quality care that protects the patient as well as the pediatric surgeon by offering best practice standards, defining optimal resources and establishing parameters by which hospitals and locum tenens agencies should abide. These guidelines are intended to foster discussion and contract negotiation as well as inform decision making for a) pediatric surgeons considering locum tenens opportunities, b) host organizations (hospitals and practices) seeking the coverage of a pediatric surgeon, and c) locum tenens companies vetting both surgeons and hospitals for appropriateness of such coverage. This Position Statement and foundational set of guidelines align with APSA's Vision (all children receive the highest quality surgical care) and Mission (to provide the best surgical care to our patients and families by supporting an inclusive community through education, discovery and advocacy).

Outcomes for pediatric acute lymphoblastic leukemia patients with intestinal perforation.

OBJECTIVES: Intestinal perforation during acute lymphoblastic leukemia (ALL) treatment in children is rare, but represents a severe complication with possible long-term consequences. In this study, we aim to provide an overview of the epidemiology and clinical characteristics of these patients; analyze surgical pathology findings for possible causes; and determine its impact on patients' therapy, nutritional status, and outcome. STUDY DESIGN: Historical chart review from January 2000 to October 2020 of children with ALL and intestinal perforation during therapy diagnosed at a single institution. Data collected included patient demographics, anthropometric measurements, ALL characteristics, diagnosis and surgery of intestinal perforation, pathology, adjustments to treatment plan, and outcome. RESULTS: Of 1840 ALL patients, 13 (0.7%) presented with intestinal perforation during treatment. Perforation occurred during induction phase in 91% of cases. Most patients underwent laparotomy with ostomy creation, and no patient died from the intervention or developed malnutrition. Pathology mainly revealed inflammation at the perforation site. Two samples showed leukemic infiltration and presence of microorganisms. Patients were able to resume ALL therapy in all cases. A total of eight patients (73%) were in first remission at last follow-up, with a median follow-up time of 42 months (interquartile range = 42). CONCLUSION: Early surgical intervention is a successful treatment approach for intestinal perforation in ALL patients. There is a clear predilection for induction phase in the occurrence of intestinal perforation in ALL patients. No specific cause was identified. Patients can receive bridging chemotherapy during surgical recovery and proceed with their treatment without apparent impact on outcome.

Interhospital variability in localization techniques for small pulmonary nodules in children: A pediatric surgical oncology research collaborative study.

BACKGROUND: Pulmonary nodules that are deep within lung parenchyma and/or small in size can be challenging to localize for biopsy. This study describes current trends in performance of image-guided localization techniques for pulmonary nodules in pediatric patients. METHODS: A retrospective review was performed on patients < 21 years of age undergoing localization of pulmonary nodules at 15 institutions. Localization and resection success, time in interventional radiology (IR), operating room (OR) and total anesthesia time, complications, and technical problems were compared between techniques. RESULTS: 225 patients were included with an average of 1.3 lesions (range 1-5). Median nodule size and depth were 4 mm (range 0-30) and 5.4 mm (0-61), respectively. The most common localization techniques were: wire + methylene blue dye (MBD) (28%), MBD only (25%), wire only (14%), technetium-99 only (11%), coil + MBD (7%) and coil only (5%). Localization technique was associated with institution (p < 0.01); technique and institution were significantly associated with mean IR, OR, and anesthesia time (all p < 0.05). Comparing techniques, there was no difference in successful IR localization (range 92-100%, p = 0.75), successful resection (94-100%, p = 0.98), IR technical problems (p = 0.22), or operative complications (p = 0.16). CONCLUSIONS: Many IR localization techniques for small pulmonary nodules in children can be successful, but there is wide variability in application by institution and in procedure time. LEVEL OF EVIDENCE: Retrospective review, Level 3.

Higher rates of regional disease but improved outcomes in pediatric versus adult melanoma.

BACKGROUND: Malignant melanoma is rare in the pediatric population and management is largely extrapolated from adult guidelines. Adult data have shown that immediate completion lymph node dissection (CLND) does not improve overall survival in selected patients with clinically node negative, sentinel lymph node-positive disease. Current nodal management in children is unknown. METHODS: The National Cancer Database (NCDB) was queried for patients with melanoma from 2012-2017 and patients categorized as pediatric (≤18 years, n=962) or adult (n=327,987). Factors associated with CLND in children with positive SLNB were evaluated in multivariable analysis. Kaplan-Meier survival analysis was performed. RESULTS: Compared to adults, children present with thicker primary tumors (T3 or T4 26.5% vs 15.5%, p<0.001), resulting in higher rates of nodal assessment with SLN biopsy or LND (60.2% vs 36.6%, p<0.001) and higher rates of regional nodal disease (35.1% vs 23.4%, p<0.001). Children underwent higher rates of CLND after SLN biopsy (10.4% vs 4.1%) and upfront lymph node dissection (15.2% vs 8.7%). A decreased rate of CLND was noted in 2017 compared to 2012 (odds ratio (OR) 0.16 (p=0.005). CLND was performed more often on multivariable analysis for older pediatric age (>12 years, OR=1.6, p=0.037) and lower extremity primary (OR=0.29, p<0.001). Children with regional nodal disease have improved 3-year overall survival compared to adults (96.5% vs 71.0%, p<0.001). CONCLUSIONS: Children with melanoma have higher rates of nodal disease but better survival than adults. As in adults, there has been a recent increase in close nodal observation rather than CLND for patients with positive SLN. Further study of nodal surveillance for pediatric patients is warranted.

Conflict resolution and negotiation in pediatric surgery.

Conflict is pervasive in pediatric surgery - it is experienced during patient care, in the operating room and between colleagues. The ethical principles of autonomy, beneficience, non-maleficience and justice are firmly anchored in any discourse regarding conflict in the setting of healthcare. The authors review key features of conflict in healthcare including the effect on patient outcomes as well as implications for the ability of the surgeon and the medical team to function appropriately and safely when conflicts arise. Although most pediatric surgery fellowship programs have no formal training in conflict management, much has been written about strategies to teach and utilize techniques of conflict mitigation and negotiation. In this article, the authors discuss common areas of conflict in the medical environment and suggest useful tools for the practicing pediatric surgeon to aid in the resolution of conflict.

Airway Clearance in Tracheomalacia.

Airway clearance is an essential part of airway maintenance to ensure the airway lumen is protected against particulate and infectious insults. The mechanisms involved in airway clearance include intrinsic structural and cellular components that can be impaired or inhibited through developmental defects and surgical interventions. Tracheomalacia is a developmental defect of the airway that can contribute to the mechanical failure to clear the airway. This chapter will review the mechanisms of airway clearance and the processes that can impair this vital process.

Surgical Resection After Talimogene Laherparepvec for Melanoma: Persistent Fuorodeoxyglucose Avidity on Positron Emission Tomography Despite No Viable Disease.

BACKGROUND: Talimogene laherparepvec (TVEC) is an injectable attenuated oncolytic herpes simplex virus (HSV-1) used in the treatment of loco regionally metastatic melanoma. Lesions managed by TVEC are generally considered unresectable at time of initiation of intralesional therapy; however, a subset of patients go on to have surgical resection of loco regionally controlled disease. We sought to review our experience with surgical excision of treated lesions to offer an insight into the radiologic correlate, treatment effect, and pathological findings of intralesional TVEC therapy. METHODS: This is a retrospective descriptive case series of patients who underwent TVEC injection at Mayo Clinic, Rochester, MN, between October 2016 and July 2020. Institutional Institutional Review Board approval was obtained. RESULTS: Twenty-one patients underwent intralesional TVEC, met inclusion criteria, and were included in this series. Seven went on to surgical excision of the injected lesions after an initial course of TVEC. Of those 7 patients, 4 had residual melanoma in the specimen on final pathology, while 3 had a complete pathologic response. All 3 patients who had no residual disease on pathology continued to have fluorodeoxyglucose (FDG) avidity on preoperative positron emission tomography scan of the excised lesions. DISCUSSION: Despite ongoing FDG avidity on PET scan, patients who have well-controlled disease and stability over time of the injected lesions may benefit from surgical excision following a course of TVEC. This may render the patient clinically disease free and/or allow them a reprieve from TVEC treatment.

Clinical significance of SLN benign capsular nevi in patients with melanoma.

BACKGROUND: Benign capsular nevi (BCN) are not infrequent in sentinel lymph nodes (SLN) of patients with melanoma. Their prognostic significance is unknown and the literature is limited. This study evaluated the clinical significance of incidentally found BCN in these patients. METHODS: A multi-institutional retrospective review of patients undergoing SLN biopsy for cutaneous melanoma between 2000 and 2016. Patients were divided into the following groups: (a) negative SLN and no BCN, (b) negative SLN and presence of BCN, (c) positive SLN seen only on immunohistochemistry (IHC), and (d) positive SLN via hematoxylin and eosin (H&E). Outcomes measured were overall survival and any recurrence. RESULTS: A total of 1253 patients were identified (group 1 = 978, group 2 = 56, group 3 = 32, and group 4 = 187). Fifty-seven percent were male and the mean age was 59.3 years. BCN was identified in 77 patients (6.2%), of which the majority was in the node-negative group (72%). Multivariable analysis showed that BCN was associated with lower recurrence rates, though not statistically significant (hazard ratio [HR] = 0.5; P = .06). IHC- and H&E-positive SLNs were associated with a higher risk of recurrence (HR = 2.4; P = .02 and 2.0, P < .0001, respectively). CONCLUSION: Patients with BCN and negative SLN had lower recurrence rates than patients with negative SLN and no BCN. Our data suggest a possible protective effect against recurrence.

Early Hospital Discharge After Helicopter Transport of Pediatric Trauma Patients: Analysis of Rates of Over and Undertriage.

OBJECTIVES: Helicopter air ambulance (HAA) of pediatric trauma patients is a life-saving intervention. Triage remains a challenge for both scene transport and interhospital transfer of injured children. We aimed to understand whether overtriage or undertriage was a feature of scene or interhospital transfer and how in or out of state transfers affected these rates. METHODS: Children (<18 years) who underwent trauma activation at a level I trauma center between 2011 and 2013 were identified and reviewed. Patients transported by HAA were compared with those transported by ground ambulance (GA). RESULTS: Of 399 pediatric patients (median age, 10.4 years; range, 0.1-17 years; 264 male [66%]), 71 (18%) were transported by HAA. Seventy-two percent of HAA patients went to the intensive care unit or the operating room from the trauma bay or suffered in-hospital mortality (vs 42% GA, P < 0.001). More patients were overtriaged (HAA with injury severity score [ISS] of <15) from interhospital transfers than from the scene (25% vs 3%, P = 0.002). Undertriage (GA with ISS >15) was acceptable at 5% from the scene and 14% from interhospital transfers (P = 0.08). Overtriage of patients with ISS less than 15 to HAA was significantly lower from in-state hospitals (22%) than out-of-state hospitals (45%) (P = 0.02). Undertriage of patients with ISS greater than 15 to GA was also lower from in-state hospitals (20%) versus out-of-state hospitals (38%) (P = 0.03). CONCLUSIONS: Triage of pediatric trauma patients to HAA remains difficult. There remains potential for improvement, particularly as regards interhospital HAA overtriage, but well developed transfer protocols (such in-state protocols) may help.

Magnetic Resonance-guided High-intensity Focused Ultrasound (MRgHIFU) Virtual Treatment Planning for Abdominal Neuroblastoma Utilizing Retrospective Diagnostic 3D CT Images.

Magnetic resonance-guided high-intensity focused ultrasound (MRgHIFU) is a novel treatment for neuroblastoma using ultrasound-induced thermal ablation with real-time MR thermometry. It is unclear which patients would be amenable to MRgHIFU given the retroperitoneal location of many neuroblastomas within the smaller pediatric abdomen. In addition, planning relies on MR scans, which are not routine in the standard pediatric neuroblastoma workup. This study sought to demonstrate that neuroblastomas are targetable with MRgHIFU and available computed tomographic imaging could be utilized for MRgHIFU virtual treatment. Cross-sectional images of 88 pediatric abdominal neuroblastoma patients were retrospectively processed with custom software to be made compatible with the Sonalleve MRgHIFU platform. Targetability measured percent treatment to lesion volume, within adequate safety margins from critical structures. All images were successfully converted into treatment planning files. Median lesion size was 191±195 cm and depth was 29±17 mm. Up to 78 (85%) patients had targetable lesions with a median targetable volume of 15% and ranging up to 79%. Targetability was highest in superficial, right upper quadrant lesions >200 cm, but limited by proximity to bowel and ribs. This study demonstrates the capacity for MRgHIFU to potentially treat the majority of abdominal neuroblastomas and the feasibility of using computed tomographic images for MRgHIFU virtual treatment planning.

Multifocal hepatoblastoma: What is the risk of recurrent disease in the remnant liver?

PURPOSE: Multifocal hepatoblastoma (HB) is often treated with total hepatectomy and transplantation owing to concerns of surgical resectability, local recurrence, and/or metachronous tumor in the remnant liver. We aimed to review HB patients to determine the risk of local recurrence in multifocal disease. METHODS: We undertook retrospective cohort analysis of all HB patients at a single tertiary referral center between 2001 and 2015. Demographics, diagnostic features, operative details, and outcomes were analyzed. RESULTS: Sixty patients underwent surgical management of HB. 39 had unifocal, and 21 had multifocal disease. Of multifocal patients, 9 underwent liver transplantation, 10 anatomic resections, and 2 nonanatomic resections. Overall, two patients had recurrence in the remnant liver - both from the unifocal group. There were equivalent distant (lung) recurrences between the groups (8% for unifocal versus 14% for multifocal), p = 0.89. At a mean of 75 months of follow-up, overall survival was 97% for unifocal patients and 86% for multifocal patients, p = 0.12. CONCLUSION: Multifocal HB was not associated with increased local recurrence in the setting of R0 resection and chemotherapy. These data do not support the contention that all patients with multifocal HB require a total hepatectomy and transplantation to reduce the incidence of local recurrence and/or metachronous tumor development. LEVEL OF EVIDENCE: Level III - Limited cohort analysis.

Management of ovarian lesions diagnosed during infancy.

PURPOSE: Prior studies of infant ovarian cysts have recommended intervention for those larger than 4 cm. We reviewed the natural history and features of those managed operatively versus nonoperatively. METHODS: A retrospective study was performed of ovarian lesions in children <1 year-old from 2000 to 2014. RESULTS: Forty patients were identified. Twenty-eight (70%) underwent operative management, while 12 (30%) were managed conservatively, including one undergoing aspiration. The mean age at surgery was 125 days. All but one patient (96%) had evidence of antenatal torsion intraoperatively or on final pathology. All resected lesions were benign. Ultrasound findings more common in those undergoing surgery included intracystic debris (p < 0.001), fluid-fluid or fluid-debris levels (p = 0.002), absence of Doppler flow (p = 0.014), solid components (p = 0.04), and calcifications (p = 0.001). Cysts managed nonoperatively had an average diameter of 2.5 cm, compared to 5.1 cm in the operative group (p < 0.001). Three of the lesions managed nonoperatively had a diameter greater than 3.5 cm (mean 5.1 cm) and were followed for an average of 153 days until resolution. CONCLUSIONS: The majority of infant ovarian lesions were excised, although none were malignant. Aspiration or observation of larger cysts was feasible and safe. Ovarian cysts in this age group should be considered for nonoperative management and closely followed. LEVEL OF EVIDENCE: IIC.

Refining How We Define Laparoscopic Expertise.

BACKGROUND: Traditional stratification of expertise in laparoscopic simulation assigns participants to novice, intermediate, or expert groups based on case numbers. We hypothesized that expert video assessment might refine this discrimination of psychomotor expertise, especially in light of new measurable parameters. MATERIALS AND METHODS: One hundred five participants performed a defined intracorporeal suturing task in the pediatric laparoscopic surgery simulator armed with force-sensing capabilities. Participants were stratified into novice, intermediate, and expert groups via three classification schemes: (1) number of complex laparoscopic cases, (2) self-declared level of expertise, and (3) average expert rating of participants' videos. Precision, time to task completion, and force analysis parameters (FAP = total, maximum and mean forces in three axes) were compared using one-way analysis of variance tests. P < .05 was considered significant. RESULTS: Participants stratified on the basis of case numbers and on the basis of self-declared level of expertise had statistically significant differences in time to task completion, but no significant difference in FAP. When participants were restratified according to expert assessment of their video performance, time to task completion as well as total and mean forces in X, Y, and Z axes allowed discrimination between novices, intermediates, and experts, thus establishing construct validity for the latter. Precision did not allow discrimination in any stratification scheme. CONCLUSION: Compared with traditional stratification, video assessment allows refined discrimination of psychomotor expertise within a simulator. Assessment of FAP may become a relevant tool for teaching and assessing laparoscopic skills.

Long term outcomes after concurrent ipsilateral nephrectomy versus kidney-sparing surgery for high-risk, intraabdominal neuroblastoma.

PURPOSE: The impact of the extent of surgical resection including nephrectomy for high-risk neuroblastoma patients is controversial. In this study, we compared the renal late effects and long-term survival for patients who underwent kidney-sparing surgery (KSS) versus concurrent ipsilateral nephrectomy (CIN) for high-risk, intraabdominal neuroblastoma (HRIN). METHODS: A retrospective analysis of patients diagnosed with HRIN between Jan 1998 and Dec 2008 in a tertiary referral center was performed. Demographics, preoperative features, surgical resection extent and outcomes were analyzed. RESULTS: Of 58 patients who underwent surgical management of HRIN, 6 underwent CIN and 52 underwent KSS. Renal image-defined risk factors (IDRFs) were more common in patients who underwent CIN. Operating time was longer and EBL higher in CIN patients. There was no difference in recurrence or overall survival between the groups. Estimated GFR (eGFR) was comparable between the groups preoperatively, but was reduced postoperatively and at long-term follow-up in patients who underwent CIN. CONCLUSION: Compared to KSS, CIN is not associated with an increase in local recurrence or inferior survival but does lead to reduced kidney function (eGFR of 90 ml/min/1.73 m2 for CIN versus 127 ml/min/1.73 m2 for KSS, p = 0.03) but without significant impact on clinical outcome. LEVELS OF EVIDENCE: III (Retrospective comparative study).

Laparoscopic Revision of Ventriculoperitoneal Shunts in Pediatric Patients May Result in Fewer Subsequent Peritoneal Revisions.

INTRODUCTION: Ventriculoperitoneal shunts (VPSs) are the mainstay of treatment of hydrocephalus but frequently need revision. We sought to directly compare the impact of laparoscopic versus open peritoneal shunt revision on the need for subsequent VPS revisions in pediatric patients. MATERIALS AND METHODS: A prospectively maintained, externally validated database of pediatric patients who underwent a first peritoneal VPS revision at a single center between 2008 and 2016 was reviewed. Outcomes, including subsequent revisions, shunt infections, operative time, and hospital stay between open and laparoscopic groups, were compared. RESULTS: A total of 148 patients underwent a first peritoneal VPS revision during the time period-40 laparoscopically and 108 open-with no significant difference in age or gender between the groups. Operative time, length of stay after shunt revision, and shunt infection rates did not vary between laparoscopic versus open revisions. There was no significant difference between need for subsequent overall (peritoneal or ventricular) shunt revisions in the laparoscopic (20%) versus the open group (34%), P = .07. However, there were significantly fewer frequent peritoneal revisions in the laparoscopic group (3% versus 15%, P = .04). CONCLUSIONS: This first cohort analysis of laparoscopic versus open VPS revision in pediatric patients suggests that laparoscopic peritoneal VPS revision may reduce the rate of subsequent peritoneal revisions without increasing shunt infections or operative time in pediatric patients.

A Systematic Review of Prenatally Diagnosed Intra-abdominal Enteric Duplication Cysts.

INTRODUCTION: With improvements in prenatal ultrasound, more abdominal enteric duplication cysts (EDCs) are diagnosed prenatally. The optimal time for operative intervention is unclear. We aimed to review the evidence supporting the indication and timing of surgery for prenatally diagnosed EDCs. MATERIALS AND METHODS: A systematic review was performed using a defined search strategy identifying articles with inclusion criteria of prenatal diagnosis of histologically confirmed EDCs. Outcomes included (1) indications for resection (symptoms vs. prophylactic) and (2) time from birth to operative intervention. RESULTS: Of 1,590 articles screened, prenatal diagnosis of histologically confirmed EDCs was made in 68 articles, detailing indications and timing for resection for 86 patients. Thirty-five patients (41%) became symptomatic early and were resected promptly at a median of 2 days of age. Indications for intervention included bowel obstruction, volvulus, bleeding, recurrent pain and diagnostic dilemma (concern for cystic neuroblastoma). There were 51 patients (59%) who were resected prophylactically at a median of 90 days of age without interval symptoms. Symptomatic cysts had a larger mean cyst diameter. There was a difference in the anatomic distribution of asymptomatic or symptomatic EDCs-gastric duplications were more frequently asymptomatic while jejunal, proximal ileal and colonic duplications were more frequently symptomatic. CONCLUSION: The optimal approach to EDCs diagnosed prenatally is not supported by strong evidence in the literature. Our systematic review indicates that almost half of the infants diagnosed prenatally become symptomatic early and are resected. In asymptomatic patients, close observation and delayed prophylactic resection in infancy can be considered.

Laparoscopic insertion of ventriculoperitoneal shunts in pediatric patients - A retrospective cohort study.

INTRODUCTION: Ventriculoperitoneal shunts (VPSs) are the mainstay of treatment of hydrocephalus but have frequent complications including shunt failure and infection. There has been no comparison of laparoscopic versus open primary VPS insertion in children. We hypothesized that laparoscopic VP shunt insertion may improve patient outcomes. METHODS: A prospectively-maintained, externally-validated database of pediatric patients who underwent VPS insertion at a single center between 2012 and 2016 was reviewed. Outcomes including subsequent revisions, shunt infections, operative time, and hospital stay between open and laparoscopic groups were compared. RESULTS: 210 patients underwent VPS insertion - 41 laparoscopically and 169 open. Operative time was longer for laparoscopic insertions. There was no difference in shunt infections, complications or length of stay. There was no difference between overall revisions or in confirmed peritoneal obstructions in the laparoscopic (12%) versus open VPS insertions (5%), p = 0.13. CONCLUSIONS: This first cohort analysis of laparoscopic versus open VPS insertion in pediatric patients indicates no difference in confirmed peritoneal obstructions. With increasing use of laparoscopic placement in some centers, it remains important to elucidate if there is a subset of pediatric patients who might benefit from this technique; possible candidates may be those who are overweight/obese or have had previous intra-abdominal surgery. LEVEL OF EVIDENCE: III - Retrospective cohort study.

Refinement in the analysis of motion within low-cost laparoscopic simulators of differing size: Implications on assessing technical skills.

BACKGROUND: Simulation is becoming more important in the teaching and assessment of technical skills. The purpose of this study was to refine the use of motion analysis parameters (MAPs) to assess performance of a defined task in low-cost pediatric laparoscopic simulators of differing size. METHODS: 105 participants performed a defined intracorporeal suturing task in large and small pediatric laparoscopic simulators. Outcomes included MAPs - path length, extreme velocity events, and extreme acceleration events in all available degrees of freedom for novices, intermediates, and experts. ANOVA p <0.05 was judged significant. RESULTS: In the smaller simulator, all MAPs discriminated between expertise groups in all degrees of freedom. In the larger simulator, all but one MAP discriminated between expertise groups. Experts demonstrated the greatest variability in performance between the larger and smaller simulators. CONCLUSION: Analysis of motion in the performance of a defined intracorporeal suturing task allowed discrimination between novices, intermediates, and experts in large and small low-cost pediatric laparoscopic simulators. Further refinement in MAPs will determine their role in surgical education. LEVEL OF EVIDENCE: Not applicable.

The Impact of Simulator Size on Forces Generated in the Performance of a Defined Intracorporeal Suturing Task: A Pilot Study.

Background: In pediatric minimal access surgery, the operative domain may vary from that of an adult to that of a neonate. This study aimed to quantify the impact of decreased operative domain on forces generated in the performance of a defined intracorporeal suturing task. Methods: One hundred five participants performed a defined intracorporeal suturing task in small and large simulators. Time to task completion and force analysis parameters (FAPs = total, maximum, and mean forces in X, Y, and Z axes) were measured. Expertise level was assigned based on the number of laparoscopic cases. Outcomes were analyzed using paired sample t-tests, P value of <.05. Results: Time to task completion varied significantly for experts between adult and pediatric simulators but not for intermediates or novices. Total, maximum, and mean forces in the X ("side to side") axis were significantly greater in the larger laparoscopic simulator for all levels of expertise. In the Y axis ("in and out" movement) and Z axis ("up and down" movement), total and mean forces were higher in the adult simulator regardless of the level of expertise. Differences in maximum force between the adult and pediatric simulators in the Z axis ("up and down" movement) varied significantly for novices and intermediates but not for experts. Conclusion: Forces were greater, particularly in the side-to-side plane, in the larger simulator for participants of all levels in the performance of this defined intracorporeal suturing task. Further analysis will determine the reasons for and implications of the increased force parameters in the simulator of larger domain.

Development of an Open-Source Laparoscopic Simulator Capable of Motion and Force Assessment: High Tech at Low Cost.

OBJECTIVE: Laparoscopic simulators help improve surgical skills in an ex vivo setting. New simulators incorporate force and motion assessment, but often at high financial cost. Our goal is to establish global access to a laparoscopic simulator, which offers both traditional summative assessment (time to task completion and precision) as well as advanced formative assessment (force and motion sensing capabilities) so that educators anywhere may be able to create simulators with increased educational value. DESIGN: A low-cost laparoscopic simulator incorporating an off-the-shelf optical sensor, inertial measurement unit, holders, and a housing unit for a microcontroller was integrated into a plastic box with a high-definition digital camera and a three-dimensional mouse. Open source software was developed to offer real-time feedback in force and motion. The system was calibrated for accuracy and consistency. RESULTS: The simulator was assembled from off-the-shelf components and open-source software. Total estimated cost was $350 United States Dollars. The mouse was calibrated by applying known forces in known directions. Linear forces measured in all axes showed linear output trends with r2-values of between 0.988 and 0.999. Accuracy in motion evaluation was evaluated and this demonstrated low average errors in the motion sensors of 5.4% to 6.8%. CONCLUSIONS: This low-cost, off-the-shelf, open-access laparoscopic simulator provides accurate and consistent measures of force and motion. We believe that collaborative efforts between surgeons and engineers can allow the creation of these surgical teaching devices at a reasonable cost such that they can be used in resource-rich and resource-limited settings.