Discrimination, Reliability, Sensitivity, and Specificity of Robotic Surgical Proficiency Assessment With Global Evaluative Assessment of Robotic Skills and Binary Scoring Metrics: Results From a Randomized Controlled Trial.

Objective: To compare binary metrics and Global Evaluative Assessment of Robotic Skills (GEARS) evaluations of training outcome assessments for reliability, sensitivity, and specificity. Background: GEARS-Likert-scale skills assessment are a widely accepted tool for robotic surgical training outcome evaluations. Proficiency-based progression (PBP) training is another methodology but uses binary performance metrics for evaluations. Methods: In a prospective, randomized, and blinded study, we compared conventional with PBP training for a robotic suturing, knot-tying anastomosis task. Thirty-six surgical residents from 16 Belgium residency programs were randomized. In the skills laboratory, the PBP group trained until they demonstrated a quantitatively defined proficiency benchmark. The conventional group were yoked to the same training time but without the proficiency requirement. The final trial was video recorded and assessed with binary metrics and GEARS by robotic surgeons blinded to individual, group, and residency program. Sensitivity and specificity of the two assessment methods were evaluated with area under the curve (AUC) and receiver operating characteristics (ROC) curves. Results: The PBP group made 42% fewer objectively assessed performance errors than the conventional group (P < 0.001) and scored 15% better on the GEARS assessment (P = 0.033). The mean interrater reliability for binary metrics and GEARS was 0.87 and 0.38, respectively. Binary total error metrics AUC was 97% and for GEARS 85%. With a sensitivity threshold of 0.8, false positives rates were 3% and 25% for, respectively, the binary and GEARS assessments. Conclusions: Binary metrics for scoring a robotic VUA task demonstrated better psychometric properties than the GEARS assessment.

Laparoscopic pyeloplasty proficiency during a residency program after adoption of a standardized simulation training program is maintained during the COVID pandemic despite reduced surgery volume

ABSTRACT Purpose: To evaluate the effect of the standardized laparoscopic simulation training program in pyeloplasty, following its implementation and during the COVID-19 pandemic. Material and Methods: A retrospective chart review was performed at Hospital de Clínicas de Porto Alegre, a tertiary referral center in south Brazil, in which 151 patients underwent laparoscopic pyeloplasty performed by residents between 2006-2021. They were divided into three groups: before and after adoption of a standardized laparoscopic simulation training program and during the COVID-19 pandemic. The main outcome was a combined negative outcome of conversion to open surgery, major postoperative complications (Clavien-Dindo III or higher) or unsuccessful procedure, defined as need for redo pyeloplasty. Results: There was a significant reduction in the combined negative outcome (21.1% vs 6.3%), surgical time (mean 200.0 min vs 177.4 min) and length of stay (median 5 days vs 3 days) after the adoption of simulation training program. These results were maintained during the COVID-19 pandemic (combined negative outcome of 6.3%, mean surgical time of 160.1 min and median length of stay of 3 days) despite a reduction in 55.4% of the surgical volume. Conclusion: A structured laparoscopic simulation program can improve outcomes of laparoscopic pyeloplasty during the learning curve.

Laparoscopic pyeloplasty proficiency during a residency program after adoption of a standardized simulation training program is maintained during the COVID pandemic despite reduced surgery volume.

PURPOSE: To evaluate the effect of the standardized laparoscopic simulation training program in pyeloplasty, following its implementation and during the COVID-19 pandemic. MATERIAL AND METHODS: A retrospective chart review was performed at Hospital de Clínicas de Porto Alegre, a tertiary referral center in south Brazil, in which 151 patients underwent laparoscopic pyeloplasty performed by residents between 2006-2021. They were divided into three groups: before and after adoption of a standardized laparoscopic simulation training program and during the COVID-19 pandemic. The main outcome was a combined negative outcome of conversion to open surgery, major postoperative complications (Clavien-Dindo III or higher) or unsuccessful procedure, defined as need for redo pyeloplasty. RESULTS: There was a significant reduction in the combined negative outcome (21.1% vs 6.3%), surgical time (mean 200.0 min vs 177.4 min) and length of stay (median 5 days vs 3 days) after the adoption of simulation training program. These results were maintained during the COVID-19 pandemic (combined negative outcome of 6.3%, mean surgical time of 160.1 min and median length of stay of 3 days) despite a reduction in 55.4% of the surgical volume. CONCLUSION: A structured laparoscopic simulation program can improve outcomes of laparoscopic pyeloplasty during the learning curve.

Association of nerve-sparing grading in robotic radical prostatectomy and trifecta outcome.

PURPOSE: To evaluate the neurovascular bundle preservation grades during robotic-assisted radical prostatectomy and compared to the trifecta combined outcome (oncologic control, continence, and sexual function) twelve months after the surgery. METHODS: Cohort of patients who underwent nerve-sparing robotic-assisted radical prostatectomy had the neurovascular bundle preservation retrospectively graded from 0 to 8 according to the Hopkins subjective visual classification. Patients then were divided into two groups, according to the median of nerve-sparing grading: those with score six or high and those with score less than six. Main outcome was the trifecta combined outcome and secondary outcomes was the individual trifecta criteria (prospective analysis). A secondary analysis with groups divided according to pre-operatory SHIM score was made. RESULTS: One hundred robotic-assisted nerve-sparing radical prostatectomy were performed, of which 83 were included. There were 53 patients with grading greater than or equal to six (group 1) and 30 patients less than six (group 2). 66.6% patients (35/53) in group 1 had a trifecta combined outcome of compared to 33.3% (10/30) in group 2 (p = 0.017). Individually, the erectile function was higher in group 1 (73.6%) compared to group 2 (46.7%) (p = 0.014). Both the results of the combined endpoint trifecta and erection were also maintained in the group with preoperative SHIM ≥ 17. CONCLUSIONS: The grading of preservation of the neurovascular bundle in radical prostatectomy is related to a better combined trifecta outcome one year after surgery.

Does quality assured eLearning provide adequate preparation for robotic surgical skills; a prospective, randomized and multi-center study.

PURPOSE: In particular after the onset of the COVID-19 pandemic, there was a precipitous rush to implement virtual and online learning strategies in surgery and medicine. It is essential to understand whether this approach is sufficient and adequate to allow the development of robotic basic surgical skills. The main aim of the authors was to verify if the quality assured eLearning is sufficient to prepare individuals to perform a basic surgical robotic task. METHODS: A prospective, randomized and multi-center study was conducted in September 2020 in the ORSI Academy, International surgical robotic training center. Forty-seven participants, with no experience but a special interest in robotic surgery, were matched and randomized into four groups who underwent a didactic preparation with different formats before carrying out a robotic suturing and anastomosis task. Didactic preparation methods ranged from a complete eLearning path to peer-reviewed published manuscripts describing the suturing, knot tying and task assessment metrics. RESULTS: The primary outcome was the percentage of trainees who demonstrated the quantitatively defined proficiency benchmark after learning to complete an assisted but unaided robotic vesico-urethral anastomosis task. The quantitatively defined benchmark was based on the objectively assessed performance (i.e., procedure steps completed, errors and critical errors) of experienced robotic surgeons for a proficiency-based progression (PBP) training course. None of the trainees in this study demonstrated the proficiency benchmarks in completing the robotic surgery task. CONCLUSIONS: PBP-based e-learning methodology is an effective training method avoiding critical errors in the suturing and knotting task. Quality assured online learning is insufficient preparation for robotic suturing and knot tying anastomosis skills. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT04541615.

Proficiency-based progression training for robotic surgery skills training: a randomized clinical trial.

OBJECTIVE: To determine whether proficiency-based progression (PBP) training leads to better robotic surgical performance compared to traditional training (TT), given that the value of PBP training for learning robotic surgical skills is unclear. MATERIALS AND METHODS: The PROVESA trial is a multicentric, prospective, randomized and blinded clinical study comparing PBP training with TT for robotic suturing and knot-tying anastomosis skills. A total of 36 robotic surgery-naïve junior residents were recruited from 16 training sites and 12 residency training programmes. Participants were randomly allocated to metric-based PBP training or the current standard of care TT, and compared at the end of training. The primary outcome was percentage of participants reaching the predefined proficiency benchmark. Secondary outcomes were the numbers of procedure steps and errors made. RESULTS: Of the group that received TT, 3/18 reached the proficiency benchmark versus 12/18 of the PBP group (i.e. the PBP group were ~10 times as likely to demonstrate proficiency [P = 0.006]). The PBP group demonstrated a 51% reduction in number of performance errors from baseline to the final assessment (18.3 vs 8.9). The TT group demonstrated a marginal improvement (15.94 vs 15.44) in errors made. CONCLUSIONS: The PROVESA trial is the first prospective randomized controlled trial on basic skills training in robotic surgery. Implementation of a PBP training methodology resulted in superior surgical performance for robotic suturing and knot-tying anastomosis performance. Compared to TT, better surgical quality could be obtained by implementing PBP training for basic skills in robotic surgery.

Selective Suturing or Sutureless Technique in Robot-assisted Partial Nephrectomy: Results from a Propensity-score Matched Analysis.

BACKGROUND: Despite efforts aimed at preserving renal function, the functional decline after robot-assisted partial nephrectomy (RAPN) is not negligible. To address the risk of intraparenchymal vessel injuries during renorrhaphy, with consequent loss of functional renal parenchyma, we introduced a new surgical technique for RAPN. OBJECTIVE: To compare perioperative patient outcomes between selective-suturing or sutureless RAPN (suRAPN) and standard RAPN (stRAPN). DESIGN, SETTING, AND PARTICIPANTS: Ninety-two consecutive patients undergoing RAPN for a renal mass performed by a high-volume surgeon at a European tertiary center were included. Propensity-score matching was used to account for baseline differences between suRAPN and stRAPN patients. INTERVENTION: RAPN using a selective-suturing or sutureless technique versus standard RAPN. OUTCOME MEASUREMENTS AND STATISTICAL ANALYSIS: Perioperative outcomes included operative time, blood loss, length of stay, and intraoperative and 30-d postoperative complications. We also evaluated trifecta achievement (warm ischemia time ≤25 min, negative surgical margins, and no perioperative complications) and the incidence of postoperative acute kidney injury (AKI). We applied χ2 tests, t tests, and Kruskal-Wallis tests to assess differences in perioperative outcomes between suRAPN and stRAPN. RESULTS AND LIMITATIONS: Overall, 29 patients (31%) were treated with suRAPN. Only one suRAPN patient experienced intraoperative complications (p = 0.9). Two suRAPN patients (6.9%) and four stRAPN patients (13.8%) experienced 30-d postoperative complications (p = 0.3). Operative time (110 vs 150 min; p < 0.01) and length of stay (2 vs 3 d; p = 0.02) were shorter for suRAPN than for stRAPN. The trifecta outcome was achieved in 25 suRAPN patients (86%) and 20 stRAPN patients (70%; p = 0.1). Only one suRAPN patient (3.4%) versus five stRAPN patients (17%) experienced postoperative AKI (p = 0.2). Finally, the decrease in the estimated glomerular filtration rate at 6-mo follow-up was lower in the suRAPN (-5.2%) than in the stRAPN group (-9.1%; p < 0.01). Lack of randomization represents the main study limitation. CONCLUSIONS: A selective-suturing or sutureless technique in RAPN is feasible and safe. Moreover, suRAPN is a lower-impact surgical procedure. We obtained promising results for trifecta and functional outcomes, but prospective randomized trials are needed to validate the impact of selective suturing or a sutureless technique on long-term functional outcomes. PATIENT SUMMARY: We assessed a new technique in robotic surgery to remove part of the kidney because of kidney cancer. Our new technique involves selective suturing or no suturing of the area from where the tumor is removed. We found that the rate of complications did not increase and the operating time and length of hospital stay were shorter using this new technique.

Urology Residents Simulation Training Improves Clinical Outcomes in Laparoscopic Partial Nephrectomy.

BACKGROUND: Partial nephrectomy (PN) is the preferred modality of treatment for small renal masses. Laparoscopic partial nephrectomy (LPN) has been adopted worldwide and a fundamental role is played by surgical skills. The need for skill instruction outside the operating room is well recognized in the modern models of surgery residency training. We aim to investigate the impact of residents' laparoscopic surgical skills training on the successful implementation of LPN in a reference public teaching hospital in southern Brazil. METHODS: We accessed all patients undergoing LPN by senior's urology residents at Hospital de Clínicas de Porto Alegre. Patients were stratified in 2 periods of time named 'LPN eras' 1 and 2, to report the training impact on the outcome. LPN era 1 was from October 2012 to February 2017 and LPN era 2 from March 2017 to June 2019. All the senior residents of LPN era 2 followed a simulation training divided into 4 years with a total training time of 244 hours before performing the LPN. Residents from LPN era 1 did not have simulation training. RESULTS: 124 patients underwent LPN during the study period, 53 (42.7%) of those were performed in LPN era 1 and 71 (57.3%) in LPN era 2. Baseline characteristics of the patients in the two groups were similar. The training performed by LPN era 2 residents was able to significantly reduce estimated blood loss, ischemia time and LOS with p value respectively 0.007, 0.001 and 0.001. LPN era 2 group also reached Trifecta in 77.5% of patients, being significantly more than in the LPN era 1 (p = 0.007). CONCLUSIONS: Simulation in residents surgical training was able to improve clinical outcomes in LPN. These data reinforce the fundamental importance of adequate residents training before performing surgery on a patient.

Bilateral kidney metastases from adenoid cystic carcinoma of lung: a case report and literature review.

Adenoid cystic carcinoma (ACC) is a rare malignant tumor, usually arising from salivary glands and rarely found in other locations. ACC is characterized by asymptomatic course, slow growth pattern, perineural invasion and high incidence of late metastasis. Renal localization of metastasis is rare. Only 12 cases of renal metastasis were published and, to our best knowledge, no case of bilateral metastasis to the kidney has ever been reported. We present a case of a 58 years old woman with bilateral renal metastasis from ACC of the right lung after fourteen years from lobectomy and radiotherapy for the primary presentation. The patient underwent bilateral robot-assisted partial nephrectomy in a two-stage approach. Despite its rare incidence and slow growth, ACC metastasis may simulate primary papillary renal carcinoma and occur many years after primary treatment. Therefore, lifelong follow-up, including abdominal imaging, is recommended.

The Impact of Previous Prostate Surgery on Surgical Outcomes for Patients Treated with Robot-assisted Radical Cystectomy for Bladder Cancer.

BACKGROUND: The feasibility and safety of robot-assisted radical cystectomy (RARC) may be undermined by unfavorable preoperative surgical characteristics such as previous prostate surgery (PPS). OBJECTIVE: To compare perioperative outcomes for patients undergoing RARC with versus without a history of PPS. DESIGN, SETTING, AND PARTICIPANTS: The study included 220 consecutive patients treated with RARC and pelvic lymph node dissection for bladder cancer at a single European tertiary centre. Of these, 43 had previously undergone PPS, defined as transurethral resection of the prostate/holmium laser enucleation of the prostate (n=21) or robot-assisted radical prostatectomy (n=22). SURGICAL PROCEDURE: RARC in patients with a history of PPS. MEASUREMENTS: Data on postoperative complications were collected according to the quality criteria for accurate and comprehensive reporting of surgical outcomes recommended by the European Association of Urology guidelines. Multivariable logistic, linear, and Poisson regression analyses were performed to test the effect of PPS on surgical outcomes. RESULTS AND LIMITATIONS: Overall, 43 patients (20%) were treated with RARC after PPS. Operative time (OT) was longer in the PPS group (360 vs 330min; p<0.001). Patients with PPS experienced higher rates of intraoperative complications (19% vs 6.8%) and higher rates of 30-d (67% vs 39%), and Clavien-Dindo >3 (33% vs 16%) postoperative complications (all p<0.05). Moreover, the positive surgical margin (PSM) rate after RARC was higher in the PPS group (14% vs 4%; p=0.03). On multivariable analyses, PPS at RARC independently predicted higher risk of intraoperative (odds ratio [OR] 2.10, 95% confidence interval [CI] 1.04-6.21; p=0.01) and 30-d complications (OR 2.26, 95% CI 1.05-5.22; p=0.02), as well as longer OT (relative risk [RR] 1.03, 95% CI 1.00-1.05; p=0.02) and length of stay (RR 1.13, 95% CI 1.02-1.26; p=0.02). Lack of randomization represents the main limitation. CONCLUSIONS: RARC in patients with a history of PPS is feasible, but it is associated with a higher risk of complications and longer OT and length of stay. Moreover, higher PSM rates have been reported for these patients. Thus, measures aimed at improving surgical outcomes appear to be warranted. PATIENT SUMMARY: We investigated the effect of previous prostate surgery (PPS) on surgical outcomes after robot-assisted removal of the bladder. We found that patients with PPS have a higher risk of complications and longer hospitalization after bladder removal. These patients deserve closer evaluation before this type of bladder operation.

Burnout syndrome in pediatric urology: A perspective during the COVID-19 pandemic - Ibero-American survey.

INTRODUCTION: Burnout syndrome is a major cause of decreased life quality, mental health, and productivity for physicians. It is strongly related to work overload and has been a scarcely studied topic in pediatric urology. During the COVID-19 pandemic, authorities' recommendations have led to big changes in pediatric urology practice worldwide. This study aimed to evaluate the level of burnout in Ibero-American pediatric urologists (IPUs) during this pandemic. MATERIAL AND METHODS: A cross-sectional study was conducted by applying an electronic survey during the COVID-19 pandemic peak to members of the two major associations of pediatric urology in Ibero-America (the Ibero-American Society of Pediatric Urology [SIUP] and the Brazilian School of Pediatric Urology [BSPU]) to evaluate demographic, pre-pandemic, and pandemic data. Burnout levels were assessed using the Copenhagen Burnout Inventory (CBI) questionnaire. RESULTS: A response rate of 40% was obtained (182 out of 455 IPU respondents). Participants were from 14 different countries in Ibero-America and 75.4% were male. Data showed that during the pandemic there was a significant decrease in weekly workload, that is: > 40 h per week (h/w) (91.4%-44.6%, p < 0.001); and >6 h/w (94.9%-45.1%%, p < 0.001) in operating room time (ORT). Personal (Pe-BO), work-related (W-BO), and patient-related (Pa-BO) burnout levels among IPUs were 26.3%, 22.3%, and 7.4%, respectively (Summary table). An important difference by gender was seen, with women suffering more from the syndrome (odds ratio of 2.67 [95% confidence interval, 1.285.58; p = 0.013] for Pe-BO and OR of 3.26 [95% CI, 1.52-7.01; p = 0.004] for W-BO). CONCLUSION: A significant decrease in workload for IPU during the pandemic was observed, as well as a low level of burnout syndrome during this time. However, the predominance of burnout in women found in this study is notable.

The impact of 5-alpha-reductase inhibitors on mortality in a prostate cancer chemoprevention setting: a meta-analysis.

PURPOSE: This study aims to evaluate the impact of 5-alpha-reductase inhibitors (5ARI) for prostate cancer (PCa) primary prevention on specific and overall mortality (primary outcomes), the incidence of PCa diagnosis and disease aggressiveness (secondary outcomes). METHODS: We searched MEDLINE, EMBASE, Cochrane, ClinicalTrials and BVS through April 2018 according to the Preferred Reporting Items for Systematic Review and Meta-analysis (PRISMA) statement to identify randomized clinical trials (RCT) and cohort studies (CS). We included articles with data on mortality or PCa incidence for men using 5ARI previously to PCa diagnosis. RESULTS: Regarding the included studies, nine had data on mortality, 16 on PCa incidence and 12 on Gleason scores (GS). We found that the use of 5ARI had no impact on overall mortality (RR 0.93 95% CI 0.78-1.11) and PCa-related mortality (RR 1.35 95% CI 0.50-3.94), nor on high-grade PCa diagnosis (RR 1.06 95% CI 0.72-1.56). We identified a relative risk reduction of 24% in moderate-grade PCa diagnosis (RR 0.76 95% CI 0.59-0.98) and low-grade PCa diagnosis (RR 0.76 95% CI 0.59-0.97) Also, a reduction of 26% in overall PCa diagnosis was observed in the RCT subgroup analysis (RR 0.74 95% CI 0.65-0.84). CONCLUSION: 5ARI significantly reduced the risk of being diagnosed with PCa, not increasing high-grade disease, overall or cancer-specific mortality. Due to the relatively short mean follow-up of most studies, the mortality analysis is limited.

Laparoscopic ureteral reconstruction in infant with congenital mid ureteric valve.

Congenital mid ureteric valve (MUV) stenosis is a very rare cause of ureteric obstruction and hydronephrosis (HN) in children. We describe how we manage laparoscopically one case of a patient with congenital MUV. We describe a 6-month-old boy born with antenatal left HN, with an anteroposterior diameter (APD) of 1,5 cm. Follow-up renal ultrasound at 3 months of age showed an increase in left kidney HN, approximately 2.5 cm below the PUJ associated with distal stenosis. Renal scintigraphy with DTPA showed an obstructive pattern. Urography scan showed an abrupt reduction in the caliber of the mid left ureter Based on a preoperative diagnosis of MUV stenosis, we performed a laparoscopic left ureteroplasty. Abrupt tapering of the left ureter at 3 cm from the PUJ was identified. Proximal ureter repair was performed before the resection of the narrowing segment. The two edges of the ureter were spatulated and continuous anastomosis was performed without tension. An antegrade JJ stent was inserted after the posterior part of the anastomosis was done. Patient made an uneventful recovery and was discharged on the first postoperative day. Laparoscopic ureteroplasty is a complex but feasible option to treat patients with congenital MUV stenosis.

Laparoscopic ureteroplasty with gonadal vein graft for long ureteral stenosis: A step by step video.

Strictures of the ureter may occur from iatrogenic injury or impacted kidney stones. Complications from ureteroscopy may result in ureteral stricture in 0,5-2% of patients. New techniques are being described in order to minimize the morbidity associated with classic approaches. This is a step-by-step video of this novel technique: a successful laparoscopic ureteroplasty with gonadal vein graft for a iatrogenic long ureteral stenosis. A 16 year old female patient, with multiple previous ureteroscopies for ureteral stones, presented with severe left lumbar pain. An abdominal CT and a pyelography were performed showing a 3 cm left mid-proximal ureteral stricture with proximal hydronephrosis. The stenotic area was identified and an anterior left ureteral incision was made. Gonadal vein was removed and prepared, being sutured in the anterior surface of the ureter. Patient was discharged in the second post operative (PO). JJ stent was removed after 1 month. A 3 month PO pyelography was performed, showing no fistula and resolution of the stricture. Twelve months after surgery, the patient was painless with symptom resolution. The use of gonadal vein as a graft for ureteral strictures is a new possible approach, although more cases are necessary to evaluate its results.

Garrahan U-Stitch laparoscopic appendicovesicostomy - Making surgery easier.

Appendicovesicostomy is an established continent urinary conduit. The development of minimally invasive techniques and the reduction of operative time instigated the search for new techniques. In this video we show the laparoscopic transabdominal technique for appendicovesicostomy using U-stitch technique as proposed by Santiago Weller et al. We present a case of a teenager with neurogenic bladder and intolerance for urethral catheterization. The procedure was performed using a transperitoneal approach. The appendix was detached from the colon preserving its pedicle. The proximal appendix was spatulated and pulled through a hiatus created in the distal vesical mucosa into the bladder using a U-stitch, on a Shanfield fashion anastomosis in the anterior wall of the bladder. Detrusor was approximated over the appendix creating an antireflux mechanism. The tip of the appendix was brought out to the right iliac fossa and ostomy was fashioned. The operative time was 180 min. A Foley catheter was placed through the conduit. The case was done without any intraoperative or postoperative complications. Laparoscopic appendicovesicostomy with U-stitch technique is feasible and can be easily done in a short operative time in centers with expertise in laparoscopic surgeries with low complexity and high reproducibility.

Proposal of a New Electrode and Modality of Electrical Stimulation for Diaphragmatic Pacemakers.

PURPOSE: This report describes the implantation of a new design of intramuscular electrode to the diaphragm and introduces a new modality of electroventilation for diaphragmatic pacemaker. DESCRIPTION: We used 22 Large White female pigs to test 68 electrodes that were implanted in the abdominal portion of the diaphragm by videolaparoscopy. Animals were submitted to a new protocol of electroventilation with an unpolarized current and a single-channel mode with 1 electrode for each hemidiaphragm during 3 hours. EVALUATION: The electrodes were easily fixed to the diaphragm with the help of a deployment device designed for this purpose. There was no evidence of clinical complications such as pneumothorax or bleeding. No significant differences were observed in arterial blood gas analysis and serum lactate levels. CONCLUSIONS: The designed electrodes provided an excellent performance in connection between the electrical stimulator and the muscle tissue. The proposal for using an unpolarized current proved to be effective in stimulating both hemidiaphragms simultaneously with only a single channel of the electrical stimulator.