Novices' learning curve in single-port surgery using three surgical training programs.

BACKGROUND: The objective of this study was to evaluate the novices' learning curves and proficiency level reached in laparoendoscopic single-site (LESS) surgery using three surgical training programs. MATERIAL AND METHODS: Participants were randomly divided into three groups, who trained in a specific practice regimen for 12 days using a laparoscopic box simulator and three tasks. Group A trained in three stages using conventional laparoscopic surgery (CLS) with straight instruments, and LESS with straight and articulating instruments for four days each. Group B trained in two stages in LESS with straight and articulating instruments for six days each. Group C trained only in LESS with articulating instruments exclusively for all 12 days. Performance was registered daily during the 12 days to evaluate the participants' progress. RESULTS: Pre- and post-training analysis of the three groups showed significant differences in performance, denoting the significant improvement in their LESS skills, with no difference between the groups. Group C reached a high level of technical competence with their specific training program in LESS, obtaining a lower asymptote and slow learning rate. CONCLUSION: Specific training programs in LESS settings using articulated instruments showed a slower learning rate than the other programs but better proficiency in the technique with the best surgical performance.

Objective psychomotor laparoscopic skills evaluation using a low-cost wearable device based on accelerometry: construct and concurrent validity study.

BACKGROUND: Motion analysis of surgical maneuvers provides useful quantitative information for the objective evaluation of the surgeons. However, surgical simulation laboratories for laparoscopic training do not usually integrate devices that help quantify the level of skills of the surgeons due to their limited resources and the high costs of new technologies. The purpose of this study is to present the construct and concurrent validity of a low-cost motion tracking system, based on a wireless triaxial accelerometer, employed to objectively evaluate psychomotor skills of surgeons during laparoscopic training. METHODS: An accelerometry system, a wireless three-axis accelerometer with appearance of wristwatch, was placed on the dominant hand of the surgeons to register the motion during the laparoscopy practice with the EndoViS simulator, which simultaneously recorded the motion of the laparoscopic needle driver. This study included the participation of 30 surgeons (6 experts, 14 intermediates and 10 novices) who performed the task of intracorporeal knot-tying suture. Using 11 motion analysis parameters (MAPs), the performance of each participant was assessed. Subsequently, the scores of the three groups of surgeons were statistically analyzed. In addition, a validity study was conducted comparing the metrics between the accelerometry-tracking system and the EndoViS hybrid simulator. RESULTS: Construct validity was achieved for 8 of the 11 metrics examined with the accelerometry system. Concurrent validity demonstrated that there is a strong correlation between the results of the accelerometry system and the EndoViS simulator in 9 of 11 parameters, showing reliability of the accelerometry system as an objective evaluation method. CONCLUSION: The accelerometry system was successfully validated. This method is potentially useful to complement the objective evaluation of surgeons during laparoscopic practice in training environments such as box-trainers and simulators.

Face, content, and construct validity of the virtual immersive operating room simulator for training laparoscopic procedures.

BACKGROUND: The aim of this work is to present the face, content, and construct validation of the virtual immersive operating room simulator (VIORS) for procedural training of surgeons' laparoscopic psychomotor skills and evaluate the immersive training experience. METHODS: The VIORS simulator consists of an HMD Oculus Rift 2016 with a visor on a 1080 × 1200 pixel OLED screen, two positioning sensors with two adapted controls to simulate laparoscopic instruments, and an acrylic base to simulate the conventional laparoscopic setup. The immersion consists of a 360° virtual operating room environment, based on the EndoSuite at Hospital Infantil de Mexico Federico Gomez, which reproduces a configuration of equipment, instruments, and common distractions in the operating room during a laparoscopic cholecystectomy procedure. Forty-five surgeons, residents, and medicine students participated in this study: 27 novices, 13 intermediates, and 5 experts. They completed a questionnaire on the realism and operating room immersion, as well as their capabilities for laparoscopic procedural training, scored in the 5-point Likert scale. The data of instrument movement were recorded and analyzed using 13 movement analysis parameters (MAPs). The experience during training with VIORS was evaluated through NASA-TLX. RESULTS: The participants were enthusiastic about the immersion and sensation levels of the VIORS simulator, with positive scores on the realism and its capabilities for procedural training using VIORS. The results proved that the VIORS simulator was able to differentiate between surgeons with different skill levels. Statistically significant differences were found in nine MAPs, demonstrating their construct validity for the objective assessment of the procedural laparoscopic performance. At cognitive level, the inversion experience proves a moderate mental workload when the laparoscopic procedure is carried out. CONCLUSION: The VIORS simulator has been successfully presented and validated. The VIORS simulator is a useful and effective device for the training of procedural laparoscopic psychomotor skills.

Steerable Surgical Instrument for Conventional and Single-Site Minimally Invasive Surgery.

Background. This article aims to present an innovative design of a steerable surgical instrument for conventional and single-site minimally invasive surgery (MIS), which improves the dexterity and maneuverability of the surgeon while offering a solution to the limitations of current tools. Methods. The steerable MIS instrument consists of a deflection structure with a curved sliding joints design that articulates the distal tip in two additional degrees of freedom (DoFs), relative to the instrument shaft, using transmission by cables. A passive ball-joint mechanism articulates the handle relative to the instrument shaft, improves wrist posture, and prevents collision of instrument handles during single-site MIS procedures. The two additional DoFs of the articulating tip are activated by a thumb-controlled device, using a joystick design mounted on the handle. This steerable MIS instrument was developed by additive manufacturing in a 3D printer using PLA polymer. Results. Prototype testing showed a maximum tip deflection of 60° in the left and right directions, with a total deflection of 120°. With the passive ball-joint fully offset, the steerable tip achieved a deflection of 90° for the right and 40° for the left direction, with a total deflection of 130°. Furthermore, the passive ball-joint mechanism in the handle obtained a maximum range of motion of 60°. Conclusions. This steerable MIS instrument concept offers an alternative to enhance the application fields of conventional and single-site MIS, increasing manual dexterity of the surgeon and the ability to reach narrow anatomies from other directions.

Impact of fetal endoscopic tracheal occlusion in fetuses with congenital diaphragmatic hernia and moderate lung hypoplasia.

OBJECTIVE: To assess the effect of Fetal Endoscopic Tracheal Occlusion (FETO) on neonatal survival in fetuses with left congenital diaphragmatic hernia (CDH) and moderate lung hypoplasia. STUDY DESIGN: CDH fetuses with moderate pulmonary hypoplasia (observed/expected lung area to head ratio between 26% and 35%, or between 36% and 45% with liver herniation) were prospectively recruited. Included patients were matched to a control group who were ineligible for FETO. Primary outcomes were survival at 28 days, at discharge, and at 6 months of age, respectively. RESULTS: 58 cases were recruited, 29 treated with FETO and 29 matched controls. Median gestational age (GA) at balloon placement and removal were 29.6 and 33.6 weeks, respectively. FETO group showed significantly lower GA at delivery (35.2 vs. 37.1 weeks, respectively, p < 0.01), higher survival at 28 days (51.7 vs. 24.1%, respectively, p = 0.03), at discharge (48.3 vs. 24.1%, respectively, p = 0.06), and at six months of age (41.4 vs. 24.1%, respectively, p = 0.16), and significantly lower length of ventilatory support (17.8 vs. 32.3 days, p = 0.01) and NICU stay (34.2 vs. 58.3 days, p = <0.01) compared to controls. CONCLUSION: FETO was associated with a non-significant increase in survival and significantly lower neonatal respiratory morbidity among CDH fetuses with moderate lung hypoplasia.

Construct validity of the SurgForce system for objective assessment of laparoscopic suturing skills.

BACKGROUND: Laparoscopic surgery requires a new set of skill to be learned by the surgeons, of which the most relevant is tissue manipulation. Excessive forces applied to the tissue can cause rupture during manipulation or ischemia when confronting both sides of the tissue. The aim of this study is to establish the construct validity of the SurgForce system for objective assessment of advanced laparoscopic skills, based on the force signal generated during suture tasks, and the development of force parameters for evaluating tissue handling interaction. METHODS: The SurgForce system, a tissue handling training device that measures dynamic force, was used to capture the force generated by surgeons with different levels of laparoscopic experience. For construct validity, 37 participants were enrolled in this study: 19 medical students, 12 residents of surgical specialties and 6 expert surgeons. All participants performed an intracorporeal knotting suture task over a synthetic tissue pad with a laparoscopic box-trainer. The force performance of the participants was analyzed using 11 force-based parameters with the application of the SurgForce system. Statistical analysis was performed between novice, intermediate, and expert groups using a Kruskal-Wallis test, and between the pairs of groups using a Mann-Whitney U-test. RESULTS: Overall, 9 of the 11 force-related parameters showed significant differences between the three study groups. Results between the pairs of groups presented significant differences in 5 force parameters proposed. Construct validity results demonstrated that the SurgForce system was able to differentiate force performance between surgeons with different levels of laparoscopic experience. CONCLUSION: The SurgForce system was successfully validated. This force system showed its potential to measure the force exerted on tissue for objective assessment of tissue handling skills in suturing tasks. Furthermore, its compact design allows the use of this device in conventional laparoscopic box-trainers.

Design of a Dynamic Force Measurement System for Training and Evaluation of Suture Surgical Skills.

The aim of this study is to present the SurgeForce system, a tissue handling training device for analysis of dynamic force applied to the tissue and objective assessment of basic surgical skills during the suture process. The SurgeForce system consists of a mechanical base formed by two platforms joint with three stainless steel springs and a three axial digital accelerometer attached to the upper platform, which detects the dynamic force caused by a surgeon when performing a suture task over a synthetic tissue pad. Accelerometer data is sent to a control unit where preprocessing to transform the raw data into a force signal is done, and then, the force signal is sent to a computer application, which register the force exerted over the synthetic tissue pad. For validation, 17 participants (6 surgeons and 11 medical students) performed three simple interrupted sutures with knot tying using the SurgeForce system. Ten force-based metrics were proposed to evaluate their performance during the suturing task. Results of the validation showed statistical differences in 8 of 10 force-based parameters for assessment of basic surgical skills during the suture task. The SurgeForce system demonstrated its capacity to differentiate force-based performance of surgeons and medical students. The SurgeForce system has been successfully validated. This system was able to distinguish force performance between experts and novices, showing its potential to distinguish surgeons with basic suture skills from those who are not yet prepared.

Development and Preliminary Validation of a Rabbit Model of Duodenal Atresia for Training in Pediatric Surgical Skills.

Duodenal atresia is a congenital defect that requires advanced surgical skills. The objective of this study is to present an anatomical defect of duodenal atresia using a rabbit model and evaluate the preliminary experience for the training of surgical skills with pediatric surgeons. Adult white New Zealand male rabbits weighing 3.0 to 4.5 kg were used to create the defect. To simulate the bottom of the dilated blind pouch, the gastric antrum of the rabbit was obliterated using a 2-0 Prolene suture, and the cecal appendix was dissected to simulate the continuation of the duodenum. Participants performed laparoscopic duodenal atresia repair in this animal model using the iPhone trainer. Thirteen pediatric surgeons with experience in laparoscopic duodenal atresia repair assessed this model with a questionnaire on 5-point Likert-type scale. Overall, the simulated model of duodenal atresia obtained a general average score of 4.39. The highest observed average was for its physical realism, whereas the lowest score was in surgical experience. The global opinion of the model obtained a score of 4.40. In addition, all surgeons answered that this rabbit model showed the same complexity as newborns and young children in the repair of this type of defect. The inclusion of new models through rabbits in pediatric surgery programs will allow the development of advanced skills of pediatric residents and surgeons.

A multicentre study to predict neonatal survival according to lung-to-head ratio and liver herniation in fetuses with left congenital diaphragmatic hernia (CDH): Hidden mortality from the Latin American CDH Study Group Registry.

OBJECTIVE: To evaluate natural history of fetuses congenital diaphragmatic hernia (CDH) prenatally diagnosed in countries where termination of pregnancy is not legally allowed and to predict neonatal survival according to lung area and liver herniation. METHODS: Prospective study including antenatally diagnosed CDH cases managed expectantly during pregnancy in six tertiary Latin American centres. The contribution of the observed/expected lung-to-head ratio (O/E-LHR) and liver herniation in predicting neonatal survival was assessed. RESULTS: From the total population of 380 CDH cases, 144 isolated fetuses were selected showing an overall survival rate of 31.9% (46/144). Survivors showed significantly higher O/E-LHR (56.5% vs 34.9%; P < .001), lower proportion of liver herniation (34.8% vs 80.6%, P < .001), and higher gestational age at birth (37.8 vs 36.2 weeks, P < 0.01) than nonsurvivors. Fetuses with an O/E-LHR less than 35% showed a 3.4% of survival; those with an O/E-LHR between 35% and 45% showed 28% of survival with liver up and 50% with liver down; those with an O/E-LHR greater than 45% showed 50% of survival rate with liver up and 76.9% with liver down. CONCLUSIONS: Neonatal mortality in CDH is higher in Latin American countries. The category of lung hypoplasia should be classified according to the survival rates in our Latin American CDH registry.

Secuestro broncopulmonar. Diagnóstico prenatal, factores pronóstico y tratamiento por cirugía fetal / Bronchopulmonary Sequestration. Prenatal diagnosis, prognostic factors and treatment by fetal surgery

Resumen ANTECEDENTES: El secuestro broncopulmonar suele diagnosticarse antes del nacimiento como una masa sólida intratorácica, homogénea e hiperecogénica, casi siempre localizada en el lóbulo inferior pulmonar. Su signo patognomónico es la demostración con Doppler color de la arteria nutricia sistémica dentro de la masa pulmonar. La historia natural de la enfermedad ha demostrado que durante la vida fetal en la mayoría de los casos la masa puede tener regresión espontánea. Una proporción importante de casos tiene rápido crecimiento de la masa con hidrotórax, compresión pulmonar e hidrops. Estos casos son de mal pronóstico y elevada mortalidad perinatal y, en estas circunstancias, la cirugía fetal es la única opción que puede mejorar el pronóstico. Para este propósito se han intentado varias técnicas de cirugía fetal pero la ideal sigue siendo un tema de controversia. OBJETIVO: Describir los métodos diagnósticos, factores pronóstico y discutir las repercusiones perinatales de cada una de las diferentes técnicas de cirugía fetal descritas en la bibliografía para el tratamiento de fetos complicados con secuestro broncopulmonar. METODOLOGÍA: La búsqueda se efectuó en Medline y PubMed de todos los artículos en inglés y español publicados entre 1990 y 2019 que tuvieran las palabras clave "bronchopulmonary sequestration", "secuestro broncopulmonar", "fetal surgery" y "cirugía fetal". Se eligieron los que describían casos de secuestro broncopulmonar tratados con alguna técnica de cirugía fetal. RESULTADOS: Se encontraron 150 artículos pero solo se seleccionaron 29 estudios que describían casos con diagnóstico prenatal de secuestro broncopulmonar tratados con alguna técnica de cirugía fetal. Para tratar el secuestro broncopulmonar grave se describieron varias técnicas de intervención fetal, entre ellas: cirugía fetal abierta, colocación de catéter de derivación toraco-amniótica, oclusión del vaso nutricio sistémico mediante guía ecográfica con láser, radiofrecuencia, embolización o escleroterapia con inyección de alcohol intravascular e, incluso, broncoscopia fetal. CONCLUSIONES: Al parecer la coagulación láser del vaso nutricio es la técnica con mejores resultados perinatales que evita la muerte fetal, la morbilidad pulmonar y la necesidad de cirugía posnatal en prácticamente todos los casos tratados; se propone como el único tratamiento potencialmente curativo.

Abstract BACKGROUND: The bronchopulmonary sequestration (BPS) is usually diagnosed prenatally as an intrathoracic hyperechoic, homogeneous, solid mass usually located in the lower pulmonary lobe. The pathognomonic sign is the demonstration of its systemic feeding artery into the lung mass by using color Doppler ultrasound. Natural history data reports that a significant proportion of BPS cases usually regress in the intrauterine period. However, a proportion of cases showed a rapid and progressive growth with development of massive pleural effusion and hydrops. Such cases present the poorest prognosis and high perinatal mortality and therefore, fetal intervention should be considered to improve prognosis. Different fetal surgery procedures have been attempted for such purposes. However, the optimal fetal therapeutica strategy remains controversial. OBJECTIVE: In the present manuscript, we describe and discuss the perinatal outcome of the different published fetal interventions in fetuses complicated with BPS. METHODOLOGY: We search in the English and Spanish literature (Medline and PubMed) for cases complicated with BPS and treated with any fetal surgical intervention including the key words "broncopulmonary sequestration" and "fetal surgery" from 1990 to 2019. RESULTS: A total of 150 references were reviewed including only 26 studies describing pregnancies with prenatal diagnosis of bronchopulmonary sequestration that were treated with any fetal surgical intervention. Several fetal surgery procedures have been attempted for the management of complicated fetuses with severe BPS. These include open fetal surgery, placement of thoracoamniotic shunts, and occlusion of the feeding blood vessel by ultrasound-guided intrafetal laser coagulation, radiofrequency ablation, coil embolization, sclerotherapy with intravascular alcohol injection and fetal bronchoscopy. CONCLUSIONS: Laser coagulation of the feeding artery appears to be the best intervention, avoiding fetal death, neonatal pulmonary morbidity and the need for postnatal surgery in virtually all cases postulating itself as the only potential curative management.

Pediatric inguinal hernia repair with a single-incision approach using an Endo Close™ suturing device.

BACKGROUND: Diverse techniques have been described for pediatric inguinal hernia repair, based on extraperitoneal [1-4] and intraperitoneal [5-8] methodologies. In this video, we describe a novel technique to repair pediatric inguinal hernia using an Endo Close™ suturing device by percutaneous puncture with a single incision. METHODS: With a transumbilical approach, a 5-mm trocar is inserted for a 30° laparoscope. A 3-mm incision is made, and the Endo Close™ suturing device (Covidien, Minneapolis, MN, USA), with a 2-0 polypropylene suture retained by the stylet, is inserted perpendicularly to the skin. An extraperitoneal dissection is made on a side the inguinal ring and the needle of the device penetrates the peritoneum through the inferior border. Then, the stylet mechanism is pushed to free the lasso inside the cavity. At the same incision site, the needle of the Endo Close™ is inserted again, but an extraperitoneal dissection is made on the other side of the ring, ensuring that the needle penetrates at the same exit orifice. Now, the suture lasso is recovered and retracted to close the ring. Finally, the suture is extracted and knots are tied extracorporeally at the level of the skin. RESULTS: A total of 34 patients (20 females and 14 males) underwent surgery with this procedure. Operative time for unilateral repair was 10-15 and 25-30 min for the bilateral repair (29 unilateral/5 bilateral). The patients experienced minimal postoperative pain. The follow-up period was 12 months with no complications, no recurrence and without cases of postoperative hydrocele. There were no injuries to the structures as vessels or vas deferens, and the esthetic outcome was excellent. CONCLUSIONS: The technique presents a simple, safe and reliable method to repair inguinal hernias in children. The long-term results of this novel technique will be evaluated in future studies.

Laparoscopic treatment of nonpalpable testicle. Factors predictive for diminished size.

PURPOSE: The purposes of this study were to demonstrate the usefulness of laparoscopy in intraabdominal testicle (IAT) and to determine factors associated with diminished size during the final outcome after laparoscopic orchidopexy. METHODS: This is a retrospective analysis of consecutive patients from 1999 to 2013 with a minimum follow-up of 1year. Patient and testicular factors were related to diminished size. RESULTS: Sixty one patients, and 92 testicles were included. Median age at operation was 42months. Initially we found 66 normal sized testes (71.7%), 22 hypotrophic (23.9%) and four atrophic (4.3%). Eighty seven testes were brought down laparoscopically, 50 in one surgical stage and 37 in two stages. Mean follow-up was 40.2months and the final outcome was success: 73.5% and diminished size: 26.5%. Variables associated with diminished size were hypotrophy during initial evaluation, short spermatic vessels, section of spermatic vessels, two-stage surgery and tension to reach contralateral inguinal ring. Multivariate analysis showed that initial hypotrophy (odds ratio [OR] 4.96, confidence interval 95% [CI] 1.36-18.10) and tension to reach contralateral ring (OR 4.11, 95% CI 1.18-14.34) were associated with diminished size. CONCLUSIONS: Laparoscopy is useful in treating IAT. Initial size and tension to reach contralateral ring are factors associated with diminished size.

Two-year outcomes after diagnostic and therapeutic fetal cystoscopy for lower urinary tract obstruction.

OBJECTIVES: Our objective is to report long-term outcome after fetal cystoscopy for lower urinary tract obstruction (LUTO), as well as to investigate the accuracy of fetal cystoscopy in diagnosing the cause of bladder outlet obstruction. METHODS: This is a retrospective cohort study of all fetuses who underwent cystoscopy for prenatal diagnosis of LUTO in three tertiary referral centers. Fetal diagnostic cystoscopy was performed to determine prenatally the cause of LUTO and to ablate the posterior urethral valves (PUV). RESULTS: A total of 50 fetal cystoscopies were performed, revealing PUV in 31 (62%) fetuses, urethral atresia (UA) in 14 (28%) fetuses, and urethral stenosis (US) in 5 (10%) fetuses. Two fetuses had trisomy 18 diagnosed after fetal cystoscopy and were excluded from the present analysis. Fetal cystoscopy was accurate in the diagnosis of the etiology of LUTO in 32/35 (91.4%). There were no survivors in the UA group. One fetus with US underwent urethral stenting and survived with normal renal function at 2 years of life. Among the infants with PUV, 17/30 (56.7%) infants survived, and 13/17 (76.5%) had normal renal function at 1 year of life; 15/28 (53.6%) infants survived, and 11/15 (73.3%) had normal renal function at 2 years. CONCLUSIONS: Fetal cystoscopy is accurate in the diagnosis of the etiology of LUTO and serves as a guide to the specific prenatal treatment. This procedure is associated with modest long-term survival (54%) but with adequate preserved normal renal function in two thirds of the infants among fetuses with PUV.

Construction and validation of a low-cost surgical trainer based on iPhone technology for training laparoscopic skills.

In this article, we describe the construction and validation of a laparoscopic trainer using an iPhone 5 and a plastic document holder case. The abdominal cavity was simulated with a clear plastic document holder case. On 1 side of the case, 2 holes for entry of laparoscopic instruments were drilled. We added a window to place the camera of the iPhone, which works as our camera of the trainer. Twenty residents carried out 4 tasks using the iPhone Trainer and a physical laparoscopic trainer. The time of all tasks were analyzed with a simple paired t test. The construction of the trainer took 1 hour, with a cost of

Tissue-engineered autologous vaginal organs in patients: a pilot cohort study.

BACKGROUND: Several disorders might require vaginal reconstruction, such as congenital abnormalities, injury, or cancer. Reconstructive techniques for which non-vaginal tissue is used can be associated with complications. We assessed the use of engineered vaginal organs in four patients with vaginal aplasia caused by Mayer-Rokitansky-Küster-Hauser syndrome (MRKHS). METHODS: We invited to participate four consecutive patients who presented over a 3-year period with congenital vaginal aplasia due to MRKHS. Patients were aged 13-18 years. We obtained a vulvar biopsy of autologous tissue from every patient. We cultured, expanded, and seeded epithelial and muscle cells onto biodegradable scaffolds. The organs were constructed and allowed to mature in an incubator in a facility approved for human-tissue manufacturing. We used a perineal approach to surgically implant these organs. We recorded history, physical examination, vaginoscopy, serial tissue biopsies, MRIs, and self-administered Female Sexual Function Index questionnaire results for all patients, with a follow-up of up to 8 years. FINDINGS: We noted no long-term postoperative surgical complications. Yearly serial biopsies showed a tri-layered structure, consisting of an epithelial cell-lined lumen surrounded by matrix and muscle, with expected components of vaginal tissue present. Immunohistochemical analysis confirmed the presence of phenotypically normal smooth muscle and epithelia. The MRIs, which showed the extent of the vaginal aplasia before surgery, showed the engineered organs and the absence of abnormalities after surgery, which was confirmed with yearly vaginoscopy. A validated self-administered Female Sexual Function Index questionnaire showed variables in the normal range in all areas tested, such as desire, arousal, lubrication, orgasm, satisfaction, and painless intercourse. INTERPRETATION: Vaginal organs, engineered from the patient's own cells and implanted, showed normal structural and functional variables with a follow-up of up to 8 years. These technologies could be useful in patients requiring vaginal reconstruction. FUNDING: Wake Forest University and Hospital Infantil de México Federico Gómez.

Optimizing the positional relationships between instruments used in laparoscopic simulation using a simple trigonometric method.

BACKGROUND: Various methods for evaluating laparoscopic skill have been reported, but without detailed information on the configuration used they are difficult to reproduce. Here we present a method based on the trigonometric relationships between the instruments used in a laparoscopic training platform in order to provide a tool to aid in the reproducible assessment of surgical laparoscopic technique. MATERIALS AND METHODS: The positions of the instruments were represented using triangles. Basic trigonometry was used to objectively establish the distances among the working ports RL, the placement of the optical port h', and the placement of the surgical target OT. RESULTS: The optimal configuration of a training platform depends on the selected working angles, the intracorporeal/extracorporeal lengths of the instrument, and the depth of the surgical target. We demonstrate that some distances, angles, and positions of the instruments are inappropriate for satisfactory laparoscopy. CONCLUSIONS: By applying basic trigonometric principles we can determine the ideal placement of the working ports and the optics in a simple, precise, and objective way. In addition, because the method is based on parameters known to be important in both the performance and quantitative quality of laparoscopy, the results are generalizable to different training platforms and types of laparoscopic surgery.

Thirty-degree optical system for laparoscopic training.

The training systems used by starting laparoscopic surgeons for visual and motor adaptation employ zero-degree optics. However, as new laparoscopic surgery techniques make such optics obsolete, there is a need to design training and adaptation tools with other optics.