Medical students pursuing surgical fields have no greater innate motor dexterity than those pursuing nonsurgical fields.

INTRODUCTION: Medical students pursue different career paths based on a variety of factors. We sought to examine the impact of innate manual dexterity, both perceived and objective, on the career interests of medical students. METHODS: Third-year medical students from the University of California, Irvine were recruited for this study. Subjects completed a pretest questionnaire followed by assessment of gross and fine motor dexterity using the Purdue Pegboard test. A total of 6 independent trials were performed, 3 for each hand. The scores were recorded as an integer value between 0 and 25. A statistical analysis was performed using student t tests, the Fischer exact test, or the χ(2) test, where appropriate. RESULTS: A total of 100 students completed the questionnaire while 58 completed the dexterity testing. Students interested in a surgical field (SF) were similar in handedness, gender, video game exposure, and learning style as those interested in a nonsurgical field (NSF). In the SF group, "personal skill set" was reported as the most common factor influencing career selection, and "interest in disease process/patient population" was reported most commonly by NSF students (p = 0.015). Although a perceived innate manual dexterity was higher among SF students compared with NSF students (p = 0.032), no significant objective differences were found in right hand, left hand, or combined dexterity scores. CONCLUSIONS: Perceived "personal skill set" may influence strongly a medical student's career choice. Despite greater perceived manual dexterity, students interested in an SF do not have greater objective innate manual dexterity than those interested in an NSF.

An in vivo evaluation of a novel spiral cut flexible ureteral stent.

OBJECTIVE: The flow characteristics, ureteral conformance, and histopathologic changes of a novel spiral cut flexible ureteral stent (Percuflex Helical, Boston Scientific, Boston, MA) were evaluated in vivo in an acute and chronic porcine model. MATERIALS AND METHODS: Flow characteristics and ureteral conformance of the novel stent were determined in 6 acute and 6 chronic swine models and compared with a control ureteral stent (Percuflex Plus, Boston Scientific). The flow characteristics were determined in vivo after ligating the renal vessels and via a nephrostomy tube delivering a standard rate of 0.9% saline at 35 cm H(2)O. Flows in the unobstructed ureter, normal stent, intraluminally obstructed stent, extraluminal obstructed stent, and both intraluminally and extraluminally obstructed conditions were determined. In the chronic animals, flow was determined at day 10, with the stent in place and immediately after stent removal. Conformance and hydronephrosis was assessed on pyelograms. Histopathologic changes were also evaluated in the chronic animals. RESULTS: The acute and chronic flow characteristics in the novel stent were equivalent to the control stent. Size and weight of the kidney, degree of hydronephrosis, stent migration, and presence of urinary tract infection were also similar between the test and control stents. There were no differences seen in histopathologic grading or degree of encrustation in either stent. The novel stent appeared to conform better to the shape of the ureter in both acute and chronic animals. CONCLUSION: The novel helical stent appears to drain as well as a standard stent and causes no increased degree of histopathologic changes in the ureter.

Validation study of a virtual reality robotic simulator--role as an assessment tool?

PURPOSE: Virtual reality simulators are often used for surgical skill training since they facilitate deliberate practice in a controlled, low stakes environment. However, to be considered for assessment purposes rigorous construct and criterion validity must be demonstrated. We performed face, content, construct and concurrent validity testing of the dV-Trainer™ robotic surgical simulator. MATERIALS AND METHODS: Urology residents, fellows and attending surgeons were enrolled in this institutional review board approved study. After a brief introduction to the dV-Trainer each subject completed 3 repetitions each of 4 virtual reality tasks on it, including pegboard ring transfer, matchboard object transfer, needle threading of rings, and the ring and rail task. One week later subjects completed 4 similar tasks using the da Vinci® robot. Subjects were assessed on total task time and total errors using the built-in scoring algorithm and manual scoring for the dV-Trainer and the da Vinci robot, respectively. RESULTS: Seven experienced and 13 novice robotic surgeons were included in the study. Experienced surgeons were defined by greater than 50 hours of clinical robotic console time. Of novice robotic surgeons 77% ranked the dV-Trainer as a realistic training platform and 71% of experienced robotic surgeons ranked it as useful for resident training. Experienced robotic surgeons outperformed novices in many dV-Trainer and da Vinci robot exercises, particularly in the number of errors. On pooled data analysis dV-Trainer total task time and total errors correlated with da Vinci robot total task time and total errors (p = 0.026 and 0.011, respectively). CONCLUSIONS: This study confirms the face, content, construct and concurrent validity of the dV-Trainer, which may have a potential role as an assessment tool.

Laparoscopic warm-up exercises improve performance of senior-level trainees during laparoscopic renal surgery.

BACKGROUND AND PURPOSE: Surgery is a high-stakes "performance." Yet, unlike athletes or musicians, surgeons do not engage in routine "warm-up" exercises before "performing" in the operating room. We study the impact of a preoperative warm-up exercise routine (POWER) on surgeon performance during laparoscopic surgery. MATERIALS AND METHODS: Serving as their own controls, each subject performed two pairs of laparoscopic cases, each pair consisting of one case with POWER (+POWER) and one without (-POWER). Subjects were randomly assigned to +POWER or -POWER for the initial case of each pairing, and all cases were performed ≥ 1 week apart. POWER consisted of completing an electrocautery skill task on a virtual reality simulator and 15 minutes of laparoscopic suturing and knot tying in a pelvic box trainer. For each case, cognitive, psychomotor, and technical performance data were collected during two different tasks: mobilization of the colon (MC) and intracorporeal suturing and knot tying (iSKT). Statistical analysis was performed using SYSTAT v11.0. RESULTS: A total of 28 study cases (14+POWER, 14-POWER) were performed by seven different subjects. Cognitive and psychomotor performance (attention, distraction, workload, spatial reasoning, movement smoothness, posture stability) were found to be significantly better in the +POWER group (P ≤ 0.05) and technical performance, as scored by two blinded laparoscopic experts, was found to be better in the +POWER group for MC (P=0.04) but not iSKT (P=0.92). Technical scores demonstrated excellent reliability using our assessment tool (Cronbach ∝=0.88). Subject performance during POWER was also found to correlate with intraoperative performance scores. CONCLUSIONS: Urologic trainees who perform a POWER approximately 1 hour before laparoscopic renal surgery demonstrate improved cognitive, psychomotor, and technical performance.

Preoperative warming up exercises improve laparoscopic operative times in an experienced laparoscopic surgeon.

BACKGROUND AND PURPOSE: Performing warm-up exercises before athletic competition or stage performance is very common; however, most surgeons do not "warm up" before performing complex surgery. We analyzed the intraoperative effects of warming up before surgery in an experienced laparoscopic surgeon. METHODS: A retrospective review of all laparoscopic partial (LPN) and radical nephrectomies (LRN) completed by an experienced laparoscopic surgeon (RVC) were analyzed according to whether warm-up exercises were performed before surgery. Routine warm-up consisted of 15 to 20 minutes of pelvic trainer suturing exercises (forehand and backhand sutures and knot tying), using both hands. Intraoperative and postoperative parameters were examined. RESULTS: LRN and LPN subjects were well matched among the warm-up group and nonwarm-up group. Patients in the LPN warm-up group did have significantly larger tumors (3.7 cm vs 2.4 cm, P=0.02). Despite larger tumors, surgical time was significantly less in the warm-up group (227 min vs 281 min, P=0 .04), and total operating room time trended toward significance (320 min vs 371 min, P=0.0501). Similarly, in the LRN group, operative times and total operating room time was significantly less in the preoperative warm-up group (P=0.0068 and P=0.014, respectively). Intraoperative and postoperative complications, estimated blood loss, positive margin rate, warm ischemia time, length of stay, changes in hemoglobin and creatinine levels from baseline were not significantly different between the two groups. CONCLUSION: Performing warm-up exercises before complex laparoscopic surgery may improve operative times and performance in the operating room, especially for complex laparoscopic surgeries.

The da Vinci(®) Surgical System overcomes innate hand dominance.

BACKGROUND AND PURPOSE: The robotic surgical platform has allowed for improved ergonomics, tremor filtration, and more precise surgical movements during minimally invasive surgery. We examined the impact of the da Vinci(®) Surgical System on the lateralization of manual dexterity, or handedness, innate to most surgeons. METHODS: Manual dexterity assessments were conducted among 19 robotic novices using two different skills tests: The Purdue Pegboard Test and a needle targeting test. After an initial robotic basic skills training seminar, subjects underwent testing using both open and robotic approaches. Test performance using both approaches was then compared among all subjects. RESULTS: The majority of subjects (84%) were right handed, and all subjects described their dominant hand as significantly or moderately more dexterous than their nondominant hand. The participants had significant differences between the dominant and nondominant hand in open skills tasks using the Purdue Pegboard test (15.4 vs 14.6 pegs, P=0.023) and needle targeting test (4.5 vs 3.7 targets, P=0.015). When the same tasks were performed using the robot, the differences in handedness were no longer observed (P=0.203, P=0.764). CONCLUSION: The da Vinci robot is capable of eliminating innate dexterity or handedness among novice surgical trainees. This provides evidence of another beneficial aspect of robot-assisted surgery over traditional laparoscopic surgery and may facilitate operative performance of complex tasks.

A history and evolution of laparoscopic nephrectomy: perspectives from the past and future directions in the surgical management of renal tumors.

June 25, 2010 marks the twentieth anniversary of the first clinical laparoscopic nephrectomy. Since the advent of this procedure a paradigm shift toward minimally invasive options for urological surgery has been witnessed, resulting in rapid technological innovations and improved patient outcomes. A history of the minimally invasive surgical management of renal masses is presented with a focus on laparoscopic nephrectomy.

Differences in grip forces among various robotic instruments and da Vinci surgical platforms.

INTRODUCTION: The da Vinci surgical platform is becoming increasingly available and utilized. Due to the lack of haptic feedback, visual cues are necessary to estimate grip forces and tissue tensions during surgery. We directly measured the grip forces of robotic EndoWrist instruments using the three available da Vinci robotic surgical platforms. METHODS: Robotic instruments were tested in the da Vinci S, Si, and Standard systems. A load cell was placed in a housing unit that allowed for measurement of the grip forces applied by the tip of each robotic instrument. Each instrument was tested six times, and all data were analyzed using Student's t-tests or analysis of variance when appropriate. RESULTS: Slight differences in grip force were seen when the instrument was tested through 2 degrees of freedom at the tip (p = 0.02, analysis of variance) and when comparing a new instrument to an older instrument (p = 0.001 at the neutral position). There was no statistical difference in grip force between the left and right robotic arms. There was a broad range of grip forces between the various robotic instruments. The lowest grip force was registered in the double fenestrated grasper (2.26 ± 0.15 N), whereas the highest was seen in the Hem-o-lok clip applier (39.92 ± 0.89 N). In comparison to the S and Si, the Standard platform appeared to have significantly higher grip forces. CONCLUSION: Different grip forces were observed among the various robotic instruments commonly used during urologic surgery and between the Standard and the S and Si platforms.