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L S Feldman

Publications and source records attributed to L S Feldman.

18 recordsLinked to original sources
PubMed2006

The MISTELS program to measure technical skill in laparoscopic surgery : evidence for reliability.

BACKGROUND: The McGill Inanimate System for Training and Evaluation of Laparoscopic Skills (MISTELS) is a series of five tasks with an objective scoring system. The purpose of this study was to estimate the interrater and test-retest reliability of the MISTELS metrics and to assess their internal consistency. METHODS: To determine interrater reliability, two trained observers scored 10 subjects, either live or on tape. Test-retest reliability was assessed by having 12 subjects perform two tests, the second immediately following the first. Interrater and test-retest reliability were assessed using intraclass correlation coefficients. Internal consistency between tasks was estimated using Cronbach's alpha. RESULTS: The interrater and test-retest reliabilities for the total scores were both excellent at 0.998 [95% confidence interval (CI), 0.985-1.00] and 0.892 (95% CI, 0.665-0.968), respectively. Cronbach's alpha for the first assessment of the test-retest was 0.86. CONCLUSIONS: The MISTELS metrics have excellent reliability, which exceeds the threshold level of 0.8 required for high-stakes evaluations. These findings support the use of MISTELS for evaluation in many different settings, including residency training programs.

Clinical Competence↗
PubMed2005

Does aggressive hydration reverse the effects of pneumoperitoneum on renal perfusion?

BACKGROUND: Although pneumoperitoneum (PP) decreases renal blood flow, it remains unclear whether this impacts renal function. Our aim was to characterize the effects of PP on renal perfusion and function using two fluid strategies for intravenous fluid administration. METHODS: Twelve 30-kg pigs were randomized into two groups: maintenance (3 cc/kg/h of normal saline (NS)) and bolus (15 cc/kg/h + 20 cc/kg NaCl bolus prior to induction of PP). Pigs were studied in a blinded fashion for 30 min prior, 60 min during, and 30 min after release of 15 mmHg CO(2) PP. Cardiac output (CO) and stroke volume (SV) were measured using an esophageal Doppler probe, renal cortical perfusion (RCP) was measured with a laser Doppler probe on the right kidney, and renal function was measured using the fractional excretion of sodium (FeNa) and urine output. Statistical analysis was performed with area-under-the-curve (AUC) analysis and analysis of variance RESULTS: AUC analysis revealed moderate effect size for CO (0.416) and small effect size for SV (0.366) and RCP (0.363), with decreases seen in the control group but not the bolus group. During PP, urine output increased in the bolus group (p = 0.04) but not in the control group; there was no difference in FeNa in either group. CONCLUSION: Aggressive fluid hydration during CO(2) PP of 15 mmHg preserves CO, SV, and RCP while increasing urine output. No effect on renal function as measured by FeNa was observed in either group.

Animals↗
PubMed2005

Relationship between subjective and objective outcome measures after Heller myotomy and Dor fundoplication for achalasia.

BACKGROUND: The purpose of this study is to assess how subjective evaluation (heartburn, dysphagia, quality of life, and satisfaction) correlates with objective data after Heller myotomy and Dor fundoplication for achalasia. METHODS: A total of 53 consecutive patients with achalasia undergoing laparoscopic Heller myotomy and Dor fundoplication were studied prospectively. Subjective evaluation was done preop and postop using the Gastroesophageal Reflux Disease Health-Related Quality of Life instrument (GERD-HRQL; 0 = best, 45 = worse), 4-point dysphagia and heartburn scales (0 = best, 3 = worst), patient satisfaction scale (0 = very satisfied, 5 = incapacitated), and the SF-12 general health-related quality-of-life score. At 3 months postop, patients were asked to undergo objective evaluation with 24-h pH testing, manometry, and endoscopy. Data are expressed as median (interquartile range) and analyzed by Wilcoxon signed rank test or Mann-Whitney U test. RESULTS: Forty-nine patients were more than 3 months postsurgery. Comparing preop to postop, improvements were found in dysphagia [3 (2-3) to 0 (0-1)], heartburn [1 (0-2) to 0 (0-1)], GERD-HRQL [13.5 (6.3-22.5) to 2 (0-5)], satisfaction [3 (3-4) to 1 (0-1)], and SF-12 mental component summary [46 (37-56) to 58 (50-59)] and physical component summary [46 (36-53) to 55 (48-56)] scores (p < 0.0001 for all). Thirty-eight patients (78%) agreed to undergo objective testing, and complete data were available for 32 (65%). Four of 32 patients (12.5%) had evidence of reflux based on 24-h pH testing. Of nine patients with GERD-HRQL >5, only two had positive pH test (22%). Of 23 patients with GERD-HRQL <5, two had positive pH test (7%). Of four tested patients with moderate to severe heartburn, two had an abnormal pH test. There was no significant relationship between GERD-HRQL score and pH test results. Lower esophageal sphincter pressure (LESP) decreased from 24 (16-35) to 13 mmHg (11-17) (p < 0.001). There was no relationship between dysphagia score and postop absolute LESP or a decrease in LESP after operation. CONCLUSIONS: Laparoscopic Heller myotomy and Dor fundoplication is an effective treatment for achalasia. Subjective evaluation can document patient satisfaction and health-related quality of life but does not accurately reflect postop reflux. Twenty-four-hour pH study is required to accurately assess reflux disease.

Adult↗
PubMed2005

Characterizing the learning curve for a basic laparoscopic drill.

BACKGROUND: The psychomotor challenges inherent in laparoscopic surgery are evident by the steep procedural "learning curves" documented throughout the literature. Few methods have been described to evaluate learning curves. The cumulative summation (CUSUM) method is a criterion-based evaluation of the learning process. The purpose of this study is to describe the CUSUM learning curves for a simple task for individuals and for a group of novice laparoscopists. METHODS: Sixteen medical students undertook four weekly sessions of 10 laparoscopic pegboard transfers in the MISTELS system. Their performance was scored and recorded for each trial. CUSUM learning curves were constructed based on the goal of achieving mean scores for senior, intermediate, or junior laparoscopists >or=95% of the time. RESULTS: Based on senior criteria, one student achieved the goal by the 40th peg transfer trial. Based on intermediate criteria, three students achieved the goal by their 40th trial (trials 21 and 36), and for junior criteria, 10 students achieved the acceptable success rate by their 40th trial (range, 26-40). CONCLUSION: CUSUM analysis suggests criterion-based practice is useful for novice laparoscopists. It allows educators to track the progress of an individual toward target criteria for each MISTELS task, to more logically allocate time for training and set attainable goals, to objectively evaluate trainee acquisition of basic laparoscopic skills, and to identify trainees who need remediation.

Clinical Competence↗
PubMed2005

Assessing the learning curve for the acquisition of laparoscopic skills on a virtual reality simulator.

BACKGROUND: The aim of this study was to develop summary metrics and assess the construct validity for a virtual reality laparoscopic simulator (LapSim) by comparing the learning curves of three groups with different levels of laparoscopic expertise. METHODS: Three groups of subjects ('expert', 'junior', and 'naïve') underwent repeated trials on three LapSim tasks. Formulas were developed to calculate scores for efficiency ('time-error') and economy of 'motion' ('motion') using metrics generated by the software after each drill. Data (mean +/- SD) were evaluated by analysis of variance (ANOVA). Significance was set at p < 0.05. RESULTS: All three groups improved significantly from baseline to final for both 'time-error' and 'motion' scores. There were significant differences between groups in time error performances at baseline and final, due to higher scores in the 'expert' group. A significant difference in 'motion' scores was seen only at baseline. CONCLUSION: We have developed summary metrics for the LapSim that differentiate among levels of laparoscopic experience. This study also provides evidence of construct validity for the LapSim.

Adult↗
PubMed2004

Should laparoscopic paraesophageal hernia repair be abandoned in favor of the open approach?

BACKGROUND: The most appropriate approach to the repair of large paraesophageal hernias remains controversial. Despite early results of excellent outcomes after laparoscopic repair, recent reports of high recurrence require that this approach be reevaluated. METHODS: For this study, 60 primary paraesophageal hernias consecutively repaired at one institution from 1990 to 2002 were reviewed. These 25 open transabdominal and 35 laparoscopic repairs were compared for operative, short-, and long-term outcomes on the basis of quality-of -life questionnaires and radiographs. RESULTS: No difference in patient characteristics was detected. Laparoscopic repair resulted in lower blood loss, fewer intraoperative complications, and a shorter length of hospital stay. No difference in general or disease-specific quality-of-life was documented. Radiographic follow-up was available for 78% open and 91% laparoscopic repairs, showing anatomic recurrence rates of 44% and 23%, respectively (p = 0.11). CONCLUSIONS: Laparoscopic repair should remain in the forefront for the management of paraesophageal hernias. However, there is considerable room for improvement in reducing the incidence of recurrence.

Adult↗
PubMed2004

Intraoperative fluid management in laparoscopic live-donor nephrectomy: challenging the dogma.

BACKGROUND: Patients undergoing laparoscopic live donor nephrectomy (LLDN) commonly receive large amounts of fluid intraoperatively to counter the negative effects of pneumoperitoneum on renal function. Our aim is to demonstrate that a low-volume fluid management strategy does not adversely affect donor or recipient outcomes. METHODS: Fifty-two patients underwent LLDN between December 2000 and January 2004. Data were collected in prospective databases, and augmented with retrospective medical record review. Donors were divided into two groups: the fluid-load group (n = 24) received > 10 ml/kg/h of intravenous crystalloids intraoperatively, while the fluid-restriction group (n = 28) received < 10 m/kg/h. RESULTS: Donors in the fluid-restriction group had a lower intraoperative urine output. There were no differences in postoperative creatinine levels (117.5 micromol/L vs 121.5 micromol/L, p = 0.8) or complications (4.2% vs 7.1%, p = 0.9). In the recipients, there were no differences in postoperative creatinine levels up to 12 months, incidence of delayed graft function (18% vs 10%, p = 0.7) or acute rejection (9% vs 5%, p = 1.0) between groups. CONCLUSION: Lower volume fluid management strategies in LLDN do not appear to worsen recipient outcomes nor are they detrimental to the donors.

Adult↗
PubMed2004

Optimization of cardiac preload during laparoscopic donor nephrectomy: a preliminary study of central venous pressure versus esophageal Doppler monitoring.

BACKGROUND: While the popularity of laparoscopic donor nephrectomy (LDN) has increased, concern persists about the potential deleterious effects of pneumoperitoneum on renal function. Thus, preload optimization with vigorous intravenous hydration has been recommended. The purpose of this study was to compare central venous pressure (CVP) monitoring with a noninvasive measure of cardiac preload (esophageal Doppler) during LDN. METHODS: Thirteen patients were studied. Following induction of general anesthesia, a Doppler probe was inserted in the lower third of the esophagus to measure flow time corrected for heart rate (FTc), which is an index of preload. In 10 patients, a catheter was placed in the right internal jugular vein and CVP measured. CVP and FTc were measured at baseline in the supine and right lateral decubitus positions, then 15 and 60 min after the establishment of CO(2) pneumoperitoneum (12-15 mmHg). IV fluids were increased if the FTc fell below 300 msec. Results are expressed as means (+/-SD). Data were analyzed using repeated measures ANOVA. RESULTS: Lateral positioning and pneumoperitoneum significantly increased CVP from baseline ( p < 0.01), while the FTc did not change ( p = 0.57). After 60 min of pneumoperitoneum, the FTc was <300 msec in only one patient. CONCLUSION: CVP is not an accurate guide for administration of IV fluids during LDN. Esophageal Doppler monitoring can be used to noninvasively follow changes in preload during LDN and is worthy of further study.

Adult↗
PubMed2003

Evaluating laparoscopic skills: setting the pass/fail score for the MISTELS system.

BACKGROUND: The McGill Inanimate System for Training and Evaluation of Laparoscopic Skills (MISTELS) was developed to assess laparoscopic skills and to score them objectively. This system has been described previously. The purpose of the current study was to determine a pass/fail threshold. METHODS: In this study, 165 individuals were tested and grouped according to their clinical competency in laparoscopic surgery. The noncompetent group consisted of medical students and surgical residents in their first 2 years of training (n = 83). The competent group consisted of chief general surgical residents in their last year of training, laparoscopy fellows, and practicing laparoscopic surgeons (n = 82). The Mann-Whitney U test was used to evaluate differences in task performance between the two groups. RESULTS: There was a significant difference in total scores and individual MISTELS task scores between the noncompetent and competent laparoscopic surgeons (189 vs 372.5; p <0.0001). By setting specific pass/fail total score thresholds (cutoff scores), competent surgeons can be discriminated from noncompetent surgeons. CONCLUSION: An objective pass/fail evaluation can be given to individuals tested with the MISTELS system.

Clinical Competence↗
PubMed2002

Does a special interest in laparoscopy affect the treatment of acute cholecystitis?

BACKGROUND: We tested the hypothesis that the treatment of patients with acute cholecystitis (AC) would be improved under the care of laparoscopic specialists. METHODS: The records of patients undergoing cholecystectomy for AC from 1 January 1996 to 31 December 1998 were reviewed retrospectively. Of 170 patients, 48 were cared for by three laparoscopic specialists (LS group), whereas 122 were treated by nine general surgeons who perform only laparoscopic cholecystectomy (LC) (GS group). The rates of successful LC, complications, and length of hospital stay were compared. Multivariate analysis was used to control for baseline differences. RESULTS: The patients in the GS group were older (median age, 63 vs 53 years; p = 0.01). In all, 31 LS patients (65%), as compared with 44 GS patients (36%), had successful laparoscopic treatment (p = 0.001). The operating time was the same (median, 70 min). The proportion of patients with postoperative complications was similar in the two groups (37% in the GS vs 31% in the LS group; p = 0.6). The median postoperative hospital stay (3 vs 5 days; p <0.01) was shorter in the LS group. On logistic regression analysis, significant predictors of a successful laparoscopic operation included LS group (p <0.01) and age (p = 0). Predictors of prolonged length of hospital stay were age (p <0.01) and comorbidity score (p <0.01), with LS group status not a significant factor (p = 0.21). CONCLUSIONS: Patients with AC are more likely to undergo successful LC if cared for by a surgeon with an interest in laparoscopy. However, length of hospital stay is influenced more by patient factors in a multivariate model.

Acute Disease↗
PubMed2001

Laparoscopic fundoplication: a model for assessing new technology in surgical procedures.

BACKGROUND: Surgical success has traditionally been judged from the surgeon's perspective. A more complete evaluation of outcome incorporates the patient's, surgeon's, and payor's perspectives. Because gastroesophageal reflux disease (GERD) is primarily a quality-of-life (QOL) problem, the evaluation of laparoscopic fundoplication (LF) is a useful model for evaluating outcomes from these 3 perspectives. METHODS: Between 1995 and 2000, 74 patients underwent primary LF for GERD. In addition to undergoing physiologic testing, 63 patients (85%) were evaluated with use of a disease-specific health-related QOL scale (GERD-HRQL), scored from 0 (no symptoms) to 45 (incapacitating symptoms). Thirty-three patients also completed a generic QOL questionnaire (SF-12), in which patient satisfaction was scored from 1 (very satisfied) to 5 (very dissatisfied). Preoperative and postoperative data were compared with use of the Wilcoxon signed rank test or the paired t test. RESULTS: The median GERD-HRQL score improved from 18 to 0 at 2 years postoperation (P <.01). The median satisfaction score improved from 5 to 1 (P <.01). The SF-12 summary scores also improved after 6 weeks postoperatively (P <.05). The mean +/- SD lower esophageal sphincter pressure rose from 7.3 +/- 4 mm Hg preoperatively to 17.5 +/- 6 postoperatively (P <.01), and the mean percentage of time that the esophagus was exposed to a pH of less than 4 declined from 14.7% +/- 12% to 1.1% +/- 2% (P <.01). The median operative time was 110 minutes, which declined with experience with the procedure (P <.01). Median postoperative stay was 2 days. CONCLUSIONS: In evaluating the outcomes of a new procedure, 3 overlapping points of view were addressed: the patient's (QOL, satisfaction), the surgeon's (physiologic changes), and the payor's (operating room time, hospital stay). With use of this framework, we found that LF for GERD improves QOL, corrects the physiologic abnormalities, and is associated with short hospitalization and operating time that declines with experience with the procedure.

Adolescent↗
PubMed2001

Operative management of "hockey groin syndrome": 12 years of experience in National Hockey League players.

BACKGROUND: At the elite level of hockey, groin injuries can threaten a player's career. The aim of this review is to describe the clinical presentation and evaluate our operative approach to "hockey groin syndrome" in National Hockey League (NHL) players. METHODS: Between November 1989 and June 2000, 22 NHL players with debilitating groin pain underwent operative exploration. A repair, including ablation of the ilioinguinal nerve and reinforcement of the external oblique aponeurosis with a Goretex (W.L. Gore & Associates, Inc, Flagstaff, Ariz) mesh, was performed. Medical records were reviewed, and the players or their trainers were contacted by telephone after a mean follow-up period of 31.2 months to assess function, symptoms, and overall satisfaction. RESULTS: All patients had tearing of the external oblique aponeurosis, with branches of the ilioinguinal nerve emerging from the torn areas. At follow-up, 18 players (82%) had no pain, whereas 4 (18%) reported mild, intermittent pain. All 22 patients returned to playing hockey, with 19 (85%) able to continue their careers in the NHL. CONCLUSIONS: The "hockey groin syndrome," marked by tearing of the external oblique aponeurosis and entrapment of the ilioinguinal nerve, is a cause of groin pain in professional hockey players. Ilioinguinal nerve ablation and reinforcement of the external oblique aponeurosis successfully treats this incapacitating entity.

Adult↗
PubMed2000

Ascorbate levels in red blood cells and urine in patients with sickle cell anemia.

UNLABELLED: Ascorbic acid can be important in sickle cell anemia (SCA) because significant oxidative stress occurs in the disease. Ascorbate could contribute to reduction of the increased oxygen free radicals generated in sickle red blood cells (SRBC) and to the recycling of vitamin E in the cells, while renal loss could contribute to the low plasma levels. Evaluation of red blood cell (RBC) and urine ascorbate in SCA has not been reported. Results showed (1) ascorbate levels in SRBC were similar to those in normals; (2) urine ascorbate excretion was increased in 36% of patients; (3) plasma levels of ascorbate were decreased. CONCLUSIONS: (1) Ascorbate is present in SRBC, most likely due to ascorbate recycling, despite increased free-radical generation. (2) The increase in renal excretion may contribute to the low plasma levels of ascorbate. (3) The presence of ample ascorbate in SRBC and decreased plasma ascorbate suggests that ascorbate movement across the SRBC membrane may differ from normal RBC.

Adult↗
PubMed1997

Deletion analysis of the fis promoter region in Escherichia coli: antagonistic effects of integration host factor and Fis.

Fis is a small DNA-binding and -bending protein in Escherichia coli that is involved in several different biological processes, including stimulation of specialized DNA recombination events and regulation of gene expression. fis protein and mRNA levels rapidly increase during early logarithmic growth phase in response to a nutritional upshift but become virtually undetectable during late logarithmic and stationary phases. We present evidence that the growth phase-dependent fis expression pattern is not determined by changes in mRNA stability, arguing in favor of regulation at the level of transcription. DNA deletion analysis of the fis promoter (fis P) region indicated that DNA sequences from -166 to -81, -36 to -26, and +107 to +366 relative to the transcription start site are required for maximum expression. A DNA sequence resembling the integration host factor (IHF) binding site centered approximately at -114 showed DNase I cleavage protection by IHF. In ihf cells, maximum cellular levels of fis mRNA were decreased more than 3-fold and transcription from fis P on a plasmid was decreased about 3.8-fold compared to those in cells expressing wild-type IHF. In addition, a mutation in the ihf binding site resulted in a 76 and 61% reduction in transcription from fis P on a plasmid in the presence or absence of Fis, respectively. Insertions of 5 or 10 bp between this ihf site and fis P suggest that IHF functions in a position-dependent manner. We conclude that IHF plays a role in stimulating transcription from fis P by interacting with a site centered approximately at -114 relative to the start of transcription. We also showed that although the fis P region contains six Fis binding sites, Fis site II (centered at -42) played a predominant role in autoregulation, Fis sites I and III (centered at +26 and -83, respectively) seemingly played smaller roles, and no role in negative autoregulation could be attributed to Fis sites IV, V, and VI (located upstream of site III). The fis P region from -36 to +7, which is not directly regulated by either IHF or Fis, retained the characteristic fis regulation pattern in response to a nutritional upshift.

Bacterial Proteins↗
PubMed1992

Speech production, syntax comprehension, and cognitive deficits in Parkinson's disease.

Speech samples were obtained that were analyzed for voice onset time (VOT) for 40 nondemented English speaking subjects, 20 with mild and 20 with moderate Parkinson's disease. Syntax comprehension and cognitive tests were administered to these subjects in the same test sessions. VOT disruptions for stop consonants in syllable initial position, similar to those noted for Broca's aphasia, occurred for nine subjects. Longer response times and errors in the comprehension of syntax as measured by the Rhode Island Test of Sentence Comprehension (RITLS) also occurred for these subjects. Anovas indicate that the VOT overlap subjects had significantly higher syntax error rates and longer response times on the RITLS than the VOT nonoverlap subjects--F(1, 70) = 12.38, p less than 0.0008; F(1, 70) = 7.70, p less than 0.007, respectively. The correlation between the number of VOT timing errors and the number of syntax errors was significant. (r = 0.6473, p less than 0.01). VOT overlap subjects also had significantly higher error rates in cognitive tasks involving abstraction and the ability to maintain a mental set. Prefrontal cortex, acting through subcortical basal ganglia pathways, is a component of the neural substrate that regulates human speech production, syntactic ability, and certain aspects of cognition. The deterioration of these subcortical pathways may explain similar phenomena in Broca's aphasia. Results are discussed in relation to "modular" theories.

Adult↗
PubMed1990

Syntax comprehension deficits in Parkinson's disease.

The comprehension of 100 different spoken English sentences was studied in 39 patients with mild to moderate Parkinson's disease (PD) using the Rhode Island Test of Language Structure. Eight of the PD patients were mildly demented, and the remaining 31 showed no cognitive deficits. Seven of the eight mildly demented patients had high comprehension error rates for sentences that had moderately complex syntax. The error rates of 28 of the 31 other, nondemented patients were low, similar to those of normal control subjects. The difference between the error rates of the demented and nondemented patients was significant (p less than .02, two-tailed t-test). The data argue against some current "modular" theories that segregate linguistic from other cognitive behavior. The destruction by PD of the midbrain regions that stimulate the frontal cortex may be responsible for both cognitive and syntactic comprehension deficits.

Aged↗