Validation of a simulator for temporomandibular joint arthroscopy.

The traditional method of surgical training has followed the 'observe, practice, and teach' model, which is useful for open surgery, but is insufficient for minimally invasive surgery. This study presents the validation of a new simulator designed for TMJ arthroscopy training. A group of 10 senior maxillofacial surgeons performed an arthroscopy procedure using the simulator. They then completed a questionnaire analyzing the realism of the simulator, its utility, and the educational quality of the audiovisual software. The mean age of the 10 surgeons was 42.6 years, and they had performed a mean 151 arthroscopies. With regard to the realism of the simulator, 80% reported that it was of an appropriate size and design and 70% referred to the very realistic positions and relationships between the internal structures. Regarding its educational potential, 80% reported the simulator to be very useful for acquiring the basic skills and to acquire the sensation of depth during access to the TMJ. Finally, 90% reported the prototype to be very useful for TMJ arthroscopy training. These preliminary results showed a high degree of approval. The general opinion of the group of experts was that the experience was rewarding and inspiring, and that the prototype has the educational potential for the achievement of basic TMJ arthroscopy skills.

Effects of pneumoperitoneum and body position on the morphology of the caudal cava vein analyzed by MRI and plastinated sections.

BACKGROUND: Pneumoperitoneum and patient positioning are essential factors during laparoscopic surgical procedures. They cause hemodynamic and anatomical changes in several abdominal organs among which the caudal cava vein (CCV) is involved. Hemodynamic changes in this vein (decreased venous return) have been described in the porcine model, but how the vein morphology and size is affected at different abdominal levels is unknown. We sought to assess the morphological and morphometrical changes in the CCV of the pig caused by pneumoperitoneum and the reverse Trendelenburg position by in vivo magnetic resonance imaging (MRI). METHODS: Six pigs were scanned via MRI under four situations: S1, control (no pneumoperitoneum); S2, control in the reverse Trendelenburg position; S3, pneumoperitoneum (14 mmHg); and S4, pneumoperitoneum in the reverse Trendelenburg position. MRI and plastinated body sections were used to evaluate the topography, morphology and cross-sectional area of the CCV. RESULTS: Two portions of the CCV were differentiated: a prehepatic portion (located between the vertebral levels L1-T15) with flat and irregular morphology, and a hepatic portion (between T14-T11) that was almost rounded. The reverse Trendelenburg position caused an increase in the lumen affecting mainly the prehepatic portion, while pneumoperitoneum caused a decrease in the total vascular lumen, exerting a greater effect on the hepatic portion. The combination of both situations resulted in a further decrease in the vascular area and global morphological changes. CONCLUSIONS: The pneumoperitoneum and reverse Trendelenburg position caused morphological and morphometrical changes in the prehepatic and hepatic portions of the CCV, which should assist in gaining a better understanding of the hemodynamic changes described in the literature.

Learning curves of basic laparoscopic psychomotor skills in SINERGIA VR simulator.

PURPOSE: Surgical simulators are currently essential within any laparoscopic training program because they provide a low-stakes, reproducible and reliable environment to acquire basic skills. The purpose of this study is to determine the training learning curve based on different metrics corresponding to five tasks included in SINERGIA laparoscopic virtual reality simulator. METHODS: Thirty medical students without surgical experience participated in the study. Five tasks of SINERGIA were included: Coordination, Navigation, Navigation and touch, Accurate grasping and Coordinated pulling. Each participant was trained in SINERGIA. This training consisted of eight sessions (R1-R8) of the five mentioned tasks and was carried out in two consecutive days with four sessions per day. A statistical analysis was made, and the results of R1, R4 and R8 were pair-wise compared with Wilcoxon signed-rank test. Significance is considered at P value <0.005. RESULTS: In total, 84.38% of the metrics provided by SINERGIA and included in this study show significant differences when comparing R1 and R8. Metrics are mostly improved in the first session of training (75.00% when R1 and R4 are compared vs. 37.50% when R4 and R8 are compared). In tasks Coordination and Navigation and touch, all metrics are improved. On the other hand, Navigation just improves 60% of the analyzed metrics. Most learning curves show an improvement with better results in the fulfillment of the different tasks. CONCLUSIONS: Learning curves of metrics that assess the basic psychomotor laparoscopic skills acquired in SINERGIA virtual reality simulator show a faster learning rate during the first part of the training. Nevertheless, eight repetitions of the tasks are not enough to acquire all psychomotor skills that can be trained in SINERGIA. Therefore, and based on these results together with previous works, SINERGIA could be used as training tool with a properly designed training program.

Decomposition and analysis of laparoscopic suturing task using tool-motion analysis (TMA): improving the objective assessment.

PURPOSE: The laparoscopic suturing task is a complex procedure that requires objective assessment of surgical skills. Analysis of laparoscopic suturing task components was performed to improve current objective assessment tools. METHODS: Twelve subjects participated in this study as three groups of four surgeons (novices, intermediates and experts). A box-trainer and organic tissue were used to perform the experiment while tool movements were recorded with the augmented reality haptic system. All subjects were right-handed and developed a surgeon's knot. The laparoscopic suturing procedure was decomposed into four subtasks. Different objective metrics were applied during tool-motion analysis (TMA). Statistical analysis was performed, and results from three groups were compared using the Jonckheere-Terpstra test, considering significant differences when P ≤ 0.05. RESULTS: Several first, second and fourth subtask metrics had significant differences between the three groups. Subtasks 1 and 2 had more significant differences in metrics than subtask 4. Almost all metrics showed superior task executions accomplished by experts (lower time, total path length and number of movements) compared with intermediates and novices. CONCLUSION: The most important subtasks during suture learning process are needle puncture and first knot. The TMA could be a useful objective assessment tool to discriminate surgical experience and could be used in the future to measure and certify surgical proficiency.

Validation of SINERGIA as training tool: a randomized study to test the transfer of acquired basic psychomotor skills to LapMentor.

PURPOSE: Laparoscopic surgery is commonly used in many surgical procedures but requires a learning process to develop the necessary skills. Virtual reality simulators play an essential role within the training curricula. This paper aims to determine whether training in SINERGIA VR simulator allows novice surgeons to improve their basic psychomotor laparoscopic skills. METHODS: Forty-two people participated in this study, including 28 unexperience medical students and 14 expert surgeons who developed previously more than 100 laparoscopic procedures. Medical students made a pre-training test in LapMentor II; then, they trained in SINERGIA and they finally accomplished a post-training test in LapMentor II. Experts just made one trial in LapMentor II. A statistical analysis was carried out and results of pre- and post-training tests of novices were compared with Wilcoxon signed-rank test. Pre- and post-training tests of novices were also compared with results of experts with Mann-Whitney U test. RESULTS: Most metrics provided by LapMentor II and included in this study show significant differences when comparing pre- and post-training tests of novices. Analysis of pre-training test of novices and experts results show significant differences in all analyzed metrics for all studied tasks. On the other hand, LapMentor was not able to distinguish between experts and novices after training in SINERGIA for any metric in the camera manipulation task and for some metrics of the other tasks. CONCLUSIONS: Training in SINERGIA VR simulator allows improvement of basic psychomotor laparoscpic skills and transferring them to another virtual simulator. Therefore, it could be used in laparoscopic surgery training programs.

Anatomical changes due to pneumoperitoneum analyzed by MRI: an experimental study in pigs.

PURPOSE: Different effects on cardiovascular and respiratory systems and liver are associated with pneumoperitoneum. This study aimed to determine the morphological changes in the abdominal anatomy as a result of increased intra-abdominal pressure due to pneumoperitoneum using MRI. METHODS: Ten healthy female pigs were used in this study. MRI studies of the abdomen in supine position were made before the creation of pneumoperitoneum and 1 h after increasing the pressure to 14 mmHg. Changes in area, volume, and longitudinal and transverse length of the liver were measured. The diameters of the lumen of the abdominal aorta, the inferior vena cava and portal vein were observed in three positions along the abdominal cavity. The position of the diaphragm after the induction of pneumoperitoneum was also analyzed. RESULTS: After induction of pneumoperitoneum, volume and transverse length of the liver was significantly increased, while peak area was decreased. Stenosis in the aortic lumen was observed (P < 0.05). Longitudinal and transverse diameters of the portal lumen were reduced, but significant differences were only found in the longitudinal diameter. Alterations in the diameter of the inferior vena cava lumen were obtained in three analyzed positions, but differences were significant only in two of them. A mean cranial displacement of the diaphragm equal to 25 mm was also observed. CONCLUSION: Increasing abdominal pressure up to laparoscopic pressure (14 mmHg) provokes morphological changes in the liver, vascular structures and diaphragm. These changes could be related to functional alterations that different organs experience after the induction of pneumoperitoneum.