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C D Smith

Publications and source records attributed to C D Smith.

At least 19 recordsLinked to original sources
PubMed2007

The effect of escalating feedback on the acquisition of psychomotor skills for laparoscopy.

BACKGROUND: In the acquisition of new skills that are difficult to master, such as those required for laparoscopy, feedback is a crucial component of the learning experience. Optimally, feedback should accurately reflect the task performance to be improved and be proximal to the training experience. In surgery, however, feedback typically is in vivo. The development of virtual reality training systems currently offers new training options. This study investigated the effect of feedback type and quality on laparoscopic skills acquisition. METHODS: For this study, 32 laparoscopic novices were prospectively randomized into four training conditions, with 8 in each group. Group 1 (control) had no feedback. Group 2 (buzzer) had audio feedback when the edges were touched. Group 3 (voiced error) had an examiner voicing the word "error" each time the walls were touched. Group 4 (both) received both the audio buzzer and "error" voiced by the examiner All the subjects performed a maze-tracking task with a laparoscopic stylus inserted through a 5-mm port to simulate the fulcrum effect in minimally invasive surgery (MIS). A computer connected to the stylus scored an error each time the edge of the maze was touched, and the subjects were made aware of the error in the aforementioned manner. Ten 2-min trials were performed by the subjects while viewing a monitor. At the conclusion of training, all the subjects completed a 2-min trial of a simple laparoscopic cutting task, with the number of correct and incorrect incisions recorded. RESULTS: Group 4 (both) made significantly more correct incisions than the other three groups (F = 12.13; df = 3, 28; p < 0.001), and also made significantly fewer errors or incorrect incisions (F = 14.4; p < 0.0001). Group 4 also made three times more correct incisions and 7.4 times fewer incorrect incisions than group 1 (control). CONCLUSIONS: The type and quality of feedback during psychomotor skill acquisition for MIS have a large effect on the strength of skills generalization to a simple MIS task and should be given serious consideration in curriculum design for surgical training using simulation tasks.

Adult↗
PubMed2006

Endoscopic ablation of intestinal metaplasia containing high-grade dysplasia in esophagectomy patients using a balloon-based ablation system.

BACKGROUND: This study aimed to determine the optimal treatment parameters for the ablation of intestinal metaplasia (IM) containing high-grade dysplasia (HGD) using a balloon-based ablation system for patients undergoing esophagectomy. METHODS: Immediately before esophagectomy, patients underwent ablation of circumferential segments of the esophagus containing IM-HGD using the HALO360 system. The treatment settings were randomized to 10, 12, or 14 J/cm2 for two, three, or four applications. After esophagectomy, multiple sections from ablation zones were microscopically evaluated. Histologic end points included maximum ablation depth (histologic layer) and complete ablation of all IM-HGD (yes/no). RESULTS: Eight men with a mean age of 57 years (range, 45-71 years) were treated, and 10 treatment zones were created. There were no device-related adverse events. At resection, there was no evidence of a transmural thermal effect. Grossly, ablation zones were clearly demarcated sections of ablated epithelium. The maximum ablation depth was the lamina propria or muscularis mucosae. The highest energy (14 J/cm2, 4 applications) incurred edema in the superficial submucosa, but no submucosa ablation. Complete ablation of IM and HGD occurred in 9 of 10 ablation zones (90%), defined as complete removal of the epithelium with only small foci of "ghost cells" representing nonviable, ablated IM-HGD and demonstrating loss of nuclei and cytoarchitectural derangement. One focal area of viable IM-HGD remained at the margin of one ablation zone (12 J/cm2, 2 applications) because of incomplete overlap. CONCLUSION: Complete ablation of IM-HGD without ablation of submucosa is possible using the HALO360 system. Ablation depth is dose related and limited to the muscularis mucosae. In one patient, small residual foci of IM-HGD at the edge of the ablation zone were attributable to incomplete overlap, which can be avoided. This study, together with nonesophagectomy IM-HGD trials currently underway, will identify the optimal treatment parameters for IM-HGD patients who would otherwise undergo esophagectomy or photodynamic therapy.

Aged↗
PubMed2006

Attempted establishment of proficiency levels for laparoscopic performance on a national scale using simulation: the results from the 2004 SAGES Minimally Invasive Surgical Trainer-Virtual Reality (MIST-VR) learning center study.

BACKGROUND: The Minimally Invasive Surgical Trainer-Virtual Reality (MIST-VR) has been well validated as a training device for laparoscopic skills. It has been demonstrated that training to a level of proficiency on the simulator significantly improves operating room performance of laparoscopic cholecystectomy. The purpose of this project was to obtain a national standard of proficiency using the MIST-VR based on the performance of experienced laparoscopic surgeons. METHODS: Surgeons attending the Society of American Gastrointestinal Endoscopic Surgeons (SAGES) 2004 Annual Scientific Meeting who had performed more than 100 laparoscopic procedures volunteered to participate. All the subjects completed a demographic questionnaire assessing laparoscopic and MIST-VR experience in the learning center of the SAGES 2004 meeting. Each subject performed two consecutive trials of the MIST-VR Core Skills 1 program at the medium setting. Each trial involved six basic tasks of increasing difficulty: acquire place (AP), transfer place (TP), traversal (TV), withdrawal insert (WI), diathermy task (DT), and manipulate diathermy (MD). Trial 1 was considered a "warm-up," and trial 2 functioned as the test trial proper. Subject performance was scored for time, errors, and economy of instrument movement for each task, and a cumulative total score was calculated. RESULTS: Trial 2 data are expressed as mean time in seconds in Table 2. CONCLUSION: Proficiency levels for laparoscopic skills have now been established on a national scale by experienced laparoscopic surgeons using the MIST-VR simulator. Residency programs, training centers, and practicing surgeons can now use these data as guidelines for performance criterion during MIST-VR skills training.

Adult↗
PubMed2006

Surgeon-initiated screening colonoscopy program based on SAGES and ASCRS recommendations in a general surgery practice.

BACKGROUND: This study aimed to determine the utility of a screening colonoscopy program initiated by general surgeons in an academic center. METHODS: New patients presenting to three general surgeons who met screening colonoscopy indications were asked whether they had undergone colorectal cancer (CRC) screening. The patients who had not undergone CRC screening were offered screening colonoscopies or referred to their gastroenterologists. RESULTS: In the first 9-month period of the program, 200 patients who met the Society of American Gastrointestinal and Endoscopic Surgeons/American Society of Colon and Rectal Surgeons indications for CRC screening were asked whether they had undergone screenings. Only 46% (n = 92) reported any prior appropriate screenings. Of the patients who elected CRC screening by the surgeons, 55 underwent full colonoscopies (2 concurrently with hemorrhoidectomies), and 2 had flexible sigmoidoscopies. As a result of screening, 10 patients (18%) required treatment: 7 had polypectomies, 2 had partial colectomies, and 1 with an indication for surgery deferred treatment. CONCLUSIONS: Most of the patients presenting to the general surgeon likely have not had CRC screening, and diligence in making appropriate recommendations should be routine. Colonoscopic findings requiring intervention are not insignificant.

Academic Medical Centers↗
PubMed2006

MRI volumetric and intensity analysis of the cerebellum in Parkinson's disease patients infused with glial-derived neurotrophic factor (GDNF).

BACKGROUND: A recent human therapeutic trial using intraputaminal infusion of glial cell-derived neurotrophic factor (GDNF) in Parkinson's disease (PD) was abruptly terminated, partly due to safety concerns raised by the finding of cerebellar lesions in monkeys given high-dose GDNF. METHODS: Magnetic resonance images from nine PD patients participating in this trial were analyzed to determine whether subtle volumetric or intensity changes could be detected in the cerebellum or elsewhere following GDNF treatment for over 1 year. Subtraction images were compared to a reference standard deviation map constructed by using identically-processed paired scans from 25 normal adults. In a separate voxel-based group morphometric (VBM) analysis of the same patient images, grey matter intensity was compared between pre and post-GDNF infusion scans using a repeated measures ANOVA with family-wise error threshold of P = 0.10. Two expert readers independently reviewed serial FLAIR images from all patients. RESULTS: (1) There were no significant cerebellar differences in any of the nine individual PD patients (difference image analysis), (2) there were no significant morphometric differences between pre- and post-GDNF scans (VBM), and (3) there were no signal abnormalities in the cerebellum detected on the FLAIR images in PD patients (clinical scan review). CONCLUSIONS: In concert with lack of evidence of cerebellar dysfunction on clinical examination, we find no imaging evidence of cerebellar injury in human subjects undergoing chronic intracerebral GDNF infusion.

Aged↗
PubMed2005

Thin-layer ablation of human esophageal epithelium using a bipolar radiofrequency balloon device.

BACKGROUND: The goal of this study was to determine the optimal treatment parameters for the ablation of human esophageal epithelium using a balloon-based bipolar radiofrequency (RF) energy electrode. METHODS: Immediately prior to esophagectomy, subjects underwent esophagoscopy and ablation of two separate, 3-cm long, circumferential segments of non-tumor-bearing esophageal epithelium using a balloon-based bipolar RF energy electrode (BARRX Medical, Inc., Sunnyvale, CA, USA). Subjects were randomized to one of three energy density groups: 8, 10, or 12 J/cm2. RF energy was applied one time (1x) proximally and two times (2x) distally. Following resection, sections from each ablation zone were evaluated using H&E and diaphorase. Histological endpoints were complete epithelial ablation (yes/no), maximum ablation depth, and residual ablation thickness after tissue slough. Outcomes were compared according to energy density group and 1x vs 2x treatment. RESULTS: Thirteen male subjects (age, 49-85 years) with esophageal adenocarcinoma underwent the ablation procedure followed by total esophagectomy. Complete epithelial removal occurred in the following zones: 10 J/cm2 (2x) and 12 J/cm2 (1x and 2x). The maximum depth of injury was the muscularis mucosae: 10 and 12 J/cm2 (both 2x). A second treatment (2x) did not significantly increase the depth of injury. Maximum thickness of residual ablation after tissue slough was only 35 microm. CONCLUSIONS: Complete removal of the esophageal epithelium without injury to the submucosa or muscularis propria is possible using this balloon-based RF electrode at 10 J/cm2 (2x) or 12 J/cm2 (1x or 2x). A second application (2x) does not significantly increase ablation depth. These data have been used to select the appropriate settings for treating intestinal metaplasia in trials currently under way.

Adenocarcinoma↗
PubMed2005

What happens to the rectus abdominus fascia after laparoscopic ventral hernia repair?

BACKGROUND: One criticism of laparoscopic ventral hernia repair (LVH) is that the rectus muscles are not re-approximated to the midline, and the effect of LVH repair on the fascial edges is unclear. Progressive migration of the fascial edges toward the midline has been observed anecdotally, but objective evidence remains limited. The purpose of this study is to observe the effect of LVH repair on the rectus abdominus fascia. METHODS: Patients undergoing LVH repair with defects > 10 cm in horizontal diameter were identified prospectively and enrolled. All were repaired laparoscopically with intraperitoneal placement of mesh (DualMesh, W.L. Gore and Associates) using a standard approach. Radio-opaque clips were placed at the fascial edges intraoperatively to mark the defect, and plain abdominal films were taken postoperatively (Time 1) to establish the initial distance between clips (measured in cm). A subsequent follow-up film was taken (Time 2), and the difference in clip distance per patient was recorded. Results were analyzed using a chi-squared test. RESULTS: Twelve patients qualified for analysis and their results were compared. Mean fascial defect size was 15.1 cm (range 8.3-22.0). With respect to change in clip distance from Times 1 to 2, three events were observed: (1) Diminished (i.e. medialized), (2) Enlarged, or (3) No Change. Ten patients (83%) medialized, one patient enlarged, and one patient showed no change (chi2 (d.f. = 2) 9.17, p < 0.0023). CONCLUSIONS: Medialization of the rectus abdominus fascia occurs in the majority of patients undergoing LVH repair. Causes for this phenomenon are unclear: however eliminating intrabdominal pressure with intraperitoneal mesh placement likely plays a role.

Adult↗
PubMed2005

Construct validation of the ProMIS simulator using a novel laparoscopic suturing task.

BACKGROUND: The use of simulation for minimally invasive surgery (MIS) skills training has many advantages over current traditional methods. One advantage of simulation is that it enables an objective assessment of technical performance. The purpose of this study was to determine whether the ProMIS augmented reality simulator could objectively distinguish between levels of performance skills on a complex laparoscopic suturing task. METHODS: Ten subjects--five laparoscopic experts and five laparoscopic novices--were assessed for baseline perceptual, visio-spatial, and psychomotor abilities using validated tests. After three trials of a novel laparoscopic suturing task were performed on the simulator, measures for time, smoothness of movement, and path distance were analyzed for each trial. Accuracy and errors were evaluated separately by two blinded reviewers to an interrater reliability of >0.8. Comparisons of mean performance measures were made between the two groups using a Mann-Whitney U test. Internal consistency of ProMIS measures was assessed with coefficient alpha. RESULTS: The psychomotor performance of the experts was superior at baseline assessment (p < 0.001). On the laparoscopic suturing task, the experts performed significantly better than the novices across all three trials (p < 0.001). They performed the tasks between three and four times faster (p < 0.0001), had three times shorter instrument path length (p < 0.0001), and had four times greater smoothness of instrument movement (p < 0.009). Experts also showed greater consistency in their performance, as demonstrated by SDs across all measures, which were four times smaller than the novice group. Observed internal consistency of ProMIS measures was high (alpha = 0.95, p < 0.00001). CONCLUSIONS: Preliminary results of construct validation efforts of the ProMIS simulator show that it can distinguish between experts and novices and has promising psychometric properties. The attractive feature of ProMIS is that a wide variety of MIS tasks can be used to train and assess technical skills.

Clinical Competence↗
PubMed2005

Memories that last in old age: motor skill learning and memory preservation.

Using an automated test panel, age-associated declines in learning, remembering and performing a novel visuomotor task were assessed in 497 normal adults ranging from 18 to 95 years old. As predicted, task performance times slowed with increasing age in the cross-sectional portion of the study. However in the subsequent longitudinal study, while motor learning was significantly slower in adults over 62 years old, motor memory was pristinely preserved in normal adults from 18 to 95 years old. When tested 2 years after the first training session and without intervening rehearsal, mean performance times were retained and continued to improve by 10% in young adults and 13% in aged adults, reflecting long lasting preservation of motor memories. While the maximum lifetime of an unpracticed, novel motor memory in humans is not known, the present study suggests that new motor memories can be retained for at least 2 years without rehearsal in normal aged adults. This age-resistant component of motor memory stands in contrast to the well-known decrements in other motor and cognitive processes with human aging.

Adolescent↗
PubMed2005

Trauma calls: role of the general surgeon and CT scanning.

BACKGROUND AND OBJECTIVE: General surgeons are required in only a minority of trauma call cases to assess for abdominal injuries. Computed tomography (CT) accurately detects blunt abdominal injuries and may have replaced the need for general surgeons at trauma calls. This study evaluated the role of general surgeons at trauma calls and assessed use of CT in cases of suspected abdominal trauma. METHODS: (a) Eighteen month analysis of trauma calls at a district general hospital and (b) three month prospective study of all trauma cases presenting to A&E. RESULTS: (a) There were 73 trauma calls and the mechanism of injury in most cases was a road traffic accident (RTA). Most patients had orthopaedic and/or neurosurgical injuries. The general surgeons assessed 22 trauma call patients. Abdominal injury was excluded in 13 (four by clinical examination and nine following CT). (b) Forty three patients fulfilled the criteria for a trauma call and 14 trauma calls were made. The mechanism of injury in most was RTA and most had orthopaedic and/or neurosurgical injuries. The general surgeons assessed 10/43 potential trauma call patients, and abdominal injury was excluded in five (one by clinical examination and four following CT). CONCLUSION: A&E staff managed most trauma calls. Most patients did not require general surgical intervention. For penetrating injuries, presence of a general surgeon remained crucial. For blunt injuries CT was an important adjunct. These data suggest that general surgeons do not routinely have to attend all trauma calls but can be called if abdominal and/or vascular injuries are specifically suspected.

Abdominal Injuries↗
PubMed2005

Longitudinal functional alterations in asymptomatic women at risk for Alzheimer's disease.

PURPOSE: The authors sought to determine whether known alterations of brain function in normal individuals who are at high risk for Alzheimer's disease (AD) worsen or stay the same after a significant interval of time. METHODS: The authors used functional magnetic resonance imaging (fMRI) to observe cortical activation during confrontation naming in 14 women with high AD risk and 10 with low risk, based on family history and apolipoprotein-E4 allele status. They repeated the identical scan protocol in the same patients after 4 years. RESULTS: fMRI activation in high-AD-risk participants was found to be further diverged from that of their low-AD-risk counterparts over this period. CONCLUSION: fMRI may report on the presence and progression of neuropathology in the ventral temporal cortex or in functionally connected regions in presymptomatic AD.

Alzheimer Disease↗
PubMed2005

Correlation between perceptual, visuo-spatial, and psychomotor aptitude to duration of training required to reach performance goals on the MIST-VR surgical simulator.

Given the dynamic nature of modern surgical education, determining factors that may improve the efficiency of laparoscopic training is warranted. The objective of this study was to analyze whether perceptual, visuo-spatial, or psychomotor aptitude are related to the amount of training required to reach specific performance-based goals on a virtual reality surgical simulator. Sixteen MS4 medical students participated in an elective skills course intended to train laparoscopic skills. All were tested for perceptual, visuo-spatial, and psychomotor aptitude using previously validated psychological tests. Training involved as many instructor-guided 1-hour sessions as needed to reach performance goals on a custom designed MIST-VR manipulation-diathermy task (Mentice AB, Gothenberg, Sweden). Thirteen subjects reached performance goals by the end of the course. Two were excluded from analysis due to previous experience with the MIST-VR (total n = 11). Perceptual ability (r = -0.76, P = 0.007) and psychomotor skills (r = 0.62, P = 0.04) significantly correlated with the number of trials required. Visuo-spatial ability did not significantly correlate with training duration. The number of trials required to train subjects to performance goals on the MIST-VR manipulation diathermy task is significantly related to perceptual and psychomotor aptitude.

Adult↗
PubMed2004

Laparoscopic palliative surgery for complicated colorectal cancer.

BACKGROUND: The aim of this study was to evaluate the feasibility and outcomes of the laparoscopic approach for the palliation of advanced complicated colorectal cancer (CRC). METHODS: We reviewed 21 laparoscopic palliative procedures for emergent complications of advanced CRC between 1994 and 2002. Intraoperative complications, estimated blood loss, transfusions, operative times, time to first bowel movement, length of hospital stay, and postoperative complications were assessed. RESULTS: Indications for surgery included perforation (n = 10), bleeding (n = 7), and obstruction (n = 4). A proximal diverting procedure was performed in all patients, and a concomitant colon resection was performed in 18 patients (86%). The mean operative time was 181 +/- 22 min. Estimated blood loss was 283 +/- 48 cc, with three patients (14%) requiring transfusions. The average length of hospital stay was 8.6 +/- 2 days, and time to first bowel movement was 61 +/- 9 h. The complication rate and the 30-day mortality rate were 33% and 0%, respectively. CONCLUSION: A laparoscopic approach to address advanced CRC is safe and effective and should be considered part of the surgeon's armamentarium for the palliation of advanced complicated CRC.

Colorectal Neoplasms↗
PubMed2004

Optimal management of the morbidly obese patient. SAGES appropriateness conference statement.

BACKGROUND: Obesity is a growing health problem that contributes to numerous life-threatening or disabling disorders, including coronary artery disease, hypertension, type 2 diabetes mellitus, hyperlipidemia, degenerative joint disease, and obstructive sleep apnea. Significant weight reduction in the morbidly obese improves or reverses associated illness and benefits well-being. The purpose of the SAGES Appropriateness Conference was to summarize the state of the art for open and laparoscopic operations for the morbidly obese. METHODS: The English literature comparing bariatric procedures was reviewed and grouped by level of evidence by three surgeons (BS, LV, and CC). From more than 1,500 articles, all conference participants were provided with reprints and table summaries of no less than 50 selected manuscripts. Ten experts were requested to present reviews and make evidence-based arguments for and against the open and laparoscopic approaches in written format. An expert panel of six surgeons, including an ethicist and patient, commented on implications of data presented. The finalized statement was e-mailed to all participants for approval and comment. RESULTS: Consensus statements were achieved on various aspects of morbid obesity, including indications for surgery, resolution of comorbid illnesses with significant weight loss, and the importance of committed bariatric program. Our panel of experts agreed, in general, to the advantages of laparoscopic approaches compared to open operations in skilled hands. CONCLUSIONS: Laparoscopic Roux-en-Y gastric bypass (RYGB) affords improved short-term recovery compared to open gastric bypass. Laparoscopic adjustable banding can be performed with lower average mortality than either RYGB or any of the malabsorptive operations, and it produces variable degrees of short-term weight loss. Prospective randomized trials are needed to compare gastric bypass, malabsorptive, and restrictive procedures.

Aftercare↗
PubMed2004

Discriminative validity of the Minimally Invasive Surgical Trainer in Virtual Reality (MIST-VR) using criteria levels based on expert performance.

BACKGROUND: Increasing constraints on the time and resources needed to train surgeons have led to a new emphasis on finding innovative ways to teach surgical skills outside the operating room. Virtual reality training has been proposed as a method to both instruct surgical students and evaluate the psychomotor components of minimally invasive surgery ex vivo. METHODS: The performance of 100 laparoscopic novices was compared to that of 12 experienced (>50 minimally invasive procedures) and 12 inexperienced (<10 minimally invasive procedures) laparoscopic surgeons. The values of the experienced surgeons' performance were used as benchmark comparators (or criterion measures). Each subject completed six tasks on the Minimally Invasive Surgical Trainer-Virtual Reality (MIST-VR) three times. The outcome measures were time to complete the task, number of errors, economy of instrument movement, and economy of diathermy. RESULTS: After three trials, the mean performance of the medical students approached that of the experienced surgeons. However, 7-27% of the scores of the students fell more than two SD below the mean scores of the experienced surgeons (the criterion level). CONCLUSIONS: The MIST-VR system is capable of evaluating the psychomotor skills necessary in laparoscopic surgery and discriminating between experts and novices. Furthermore, although some novices improved their skills quickly, a subset had difficulty acquiring the psychomotor skills. The MIST-VR may be useful in identifying that subset of novices.

Adult↗
PubMed2003

Laparoscopic vs open resection for the treatment of diverticular disease.

INTRODUCTION: The aim of this study was to evaluate whether laparoscopic colon resection (LCR) offers any advantages over open colon resection (OCR) in the treatment of diverticular disease. METHODS: Between 1992 and 2002, 95 patients underwent LCR and 80 patients underwent OCR for the treatment of diverticular disease. Demographics, details of operative procedure, outcome, and pathology were compared. RESULTS: Patients in both groups were matched for age, sex, body mass index, history of previous abdominal operations, comorbidities, location of the disease, and presence of complications. LCR resulted in significantly less estimated blood loss and postoperative complications, shorter time to first bowel movement, and shorter length of stay than the OCR. There was no difference in operative time, intraoperative complications, mortality rates between groups. CONCLUSIONS: LCR is a safe and effective approach for the treatment of patients with diverticular disease. It results in less estimated blood loss, shorter time to first bowel movement, less postoperative complications, and shorter length of hospital stay.

Aged↗