Tensile properties of the human glenoid labrum

Human fresh-frozen cadaveric glenoid labrae from 16 donors were harvested and ten of these had no gross degeneration. These ten were divided into eight equal circumferential sections. Each section was cut to produce test-samples from the core layer with a cross-section of 1 x 1 mm. Tensile testing was performed within a controlled environment unit at 37 +/- 1 degrees C and 100% relative humidity. Each test-sample was precycled to a quasi-static state to alleviate the effects of deep-freezing, prior to final testing. The tangent modulus was calculated for each test-sample before and after a 5-min period of stress relaxation and at yield. The mean elastic modulus and yield stress of the glenoid labrum were 22.8 +/- 11.4 and 2.5 +/- 2.1 MPa, respectively. The anterosuperior portion had a lower elastic modulus and lower yield stress than the inferior portion (both P < 0.02). The pre-stress relaxation tangent modulus was significantly lower than the post-stress relaxation tangent modulus for all portions of the labrum. The glenoid labrum has similar tensile material properties to articular cartilage. Its elastic modulus varies around its circumference. This suggests that the labrum may encounter different forces at different positions.

Brain structural alterations before mild cognitive impairment

OBJECTIVE

To determine whether alterations of brain structure in normal aged individuals precede the development of mild cognitive impairment (MCI) or Alzheimer disease (AD).

BACKGROUND

Persons with MCI and AD demonstrate cortical volume losses vs asymptomatic aged individuals, particularly in the hippocampus, amygdala, and entorhinal cortex. It is unknown whether these losses or other volumetric changes are present, and to what degree, in cognitively normal individuals before the clinical diagnosis of MCI.

METHODS

Structural MRI was performed on a cross-section of 136 longitudinally examined normal aged subjects. All subjects were cognitively normal at the time of their scan, but 23 later developed MCI, and 9 of these 23 went on to an AD diagnosis. Extracted volumes from voxel-based morphometric analysis were combined with clinical data to compare the 23 subjects who eventually developed MCI to 113 subjects who remained cognitively normal over an average follow-up of 5.4 years.

RESULTS

Initially normal subjects who eventually developed MCI demonstrated decreased gray matter volumes in the anteromedial temporal lobes bilaterally and left angular gyrus while still cognitively normal.

CONCLUSION

Structural brain changes in anatomic areas involved in higher cognitive processes precede clinical signs and symptoms in longitudinally followed normal subjects destined to develop mild cognitive impairment.

Radiofrequency energy delivery to the lower esophageal sphincter (Stretta procedure) in patients with recurrent reflux after antireflux surgery: can surgery be avoided?

BACKGROUND

Recurrent reflux following antireflux surgery (ARS) can be difficult to manage, especially in patients who also fail medical management. In these patients, redo ARS remains the only treatment option. Endoscopic radiofrequency energy delivery to the lower esophageal sphincter (the Stretta procedure; Stretta, Curon, Sunnyvale, CA) has been shown to significantly decreased symptom scores and improve quality of life in patients with gastroesophageal reflux disease (GERD). The aim of this study was to evaluate the use of the Stretta procedure in treating patients with recurrent reflux after fundoplication.

METHODS

Between March 2002 and December 2003, eight patients with recurrent reflux following ARS underwent the Stretta procedure. All patients were asked to complete an institutional symptom survey pre-Stretta and at 1, 6, and 12 months after the procedure. Patients rated 7 reflux-related symptoms (heartburn, dysphagia, regurgitation, cough, voice changes/hoarseness, asthma, chest pain) on a 0 (none) to 3 (severe) scale. Data were analyzed using a Wilcoxon matched pairs signed rank test where appropriate.

RESULTS

Complete data were obtained for seven of the eight patients, with a median follow-up of 253 days (range, 67-378 days). One patient was lost to follow-up and not included in our analysis. Symptom scores decreased significantly, with six patients noting both improved typical and atypical symptoms. Overall, six patients (85%) were satisfied with their results.

CONCLUSIONS

Based on this small series, the Stretta procedure significantly reduces subjective symptoms of GERD. The Stretta procedure may serve an important role as an additional management strategy to help manage recurrent GERD after ARS.

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.

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.

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.

Updated cardiac safety results of dose-dense (DD) doxorubicin and cyclophosphamide (AC) followed by paclitaxel (T) with trastuzumab (H) in HER2/neu overexpressed/amplified breast cancer (BCA)

582

Background: DD q 2 weekly (w) AC → T is superior to conventionally scheduled (cs) AC → T and safe w/long follow-up (Hudis et al, SABCS 2005). With q 3 wk AC, adjuvant (adj) H is safe and effective (Romond et al and Perez et al, NEJM 2005). We therefore tested DD q 2 w AC → T + H × 1 year (y) as adj treatment (Rx) of patients (pts) with HER2/neu (+) BCA to determine cardiac safety. Based on the reported cardiac event (CE) rate of ≤ 4% in the randomized trials using cs chemotherapy (CRx) + H, we evaluated DD q 2 w AC → T + H with a 1° endpoint of cardiac safety defined as discontinuation (DC) of H due to 1) cardiac death or 2) congestive heart failure (CHF). The 2° endpoint is time to recurrence and overall survival. Methods: Pts with HER2/Neu IHC 3+ or FISH-amplified BCA were enrolled, regardless of tumor size or nodal status. Rx consisted of AC at 60/600 mg/m2 × 4 → T at 175 mg/m2 × 4 q 2 w w/pegfilgrastim 6 mg on d 2 + H × 1 y. Multi-gated radionuclide angiography scan (MUGA) is obtained at baseline and at months (mo) 2 (after AC × 4), 6 (after T × 4), 9, and 18. Pts w/baseline LVEF of ≥ 55% and w/o cardiac illnesses are eligible. Pts w/significant (sig) asymptomatic (asx) LVEF ↓ after DD AC based on mo 2 MUGA did not receive H, and pts w/sig asx LVEF ↓ during H had it DC’d. If the CE rate is > 4%, Rx is deemed not feasible. Results: From January 4, 2005 to November 1, 2005, 70 pts were enrolled. Median (med) age is 49 years (range, 27–72). Forty one of 70 pts (60%) had node (+) BC and 27/70 pts (40%) had (-) nodes. Med baseline LVEF is 68% (range, 55%-81%). As of January 9, 2005, all pts had mo 2 MUGA after DD AC and there is no sig LVEF ↓ and the med LVEF is 67% (range, 58%-79%). To date 39 pts had mo 6 MUGA w/med LVEF of 66% (range, 56%-75%) and one pt had a sig asx LVEF ↓ from baseline of 74% to 56%; H was DC’d. Twenty-three pts had mo 9 MUGA w/a med LVEF of 64% (range, 57%-69%). One patient had clinical CHF at mo 4 w/EF of 45% and improved sig w/cardiac medications. One had pneumonitis during radiation (RT). One had atrial fibrillation w/pericarditis after completion of RT. Discussion: DD AC → T + H appears to have an acceptable cardiac toxicity profile w/1/70 pts having a CE. Updated cardiac safety data will be presented.

[Table: see text]

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

Comparative results of endoluminal gastroplasty and laparoscopic antireflux surgery for the treatment of GERD

BACKGROUND

Transoral endoluminal gastroplasty (EG) by the Bard Endocinch device is available for the treatment of gastroesophageal reflux disease (GERD). This study assessed the early (<or=12 months) outcomes in patients undergoing EG performed by one gastroenterologist compared with another set of patients referred by the same gastroenterologist for laparoscopic antireflux surgery (LAS) at a foregut surgery center.

METHODS

From June 2000 to July 2002, 87 consecutive patients cared for by a single gastroenterologist were diagnosed with refractory GERD and underwent either EG (n = 47) or referral for LAS (n = 40). Preoperative evaluation included symptom assessment, pH studies, and motility studies. Outcomes were assessed by symptomatic improvement and dependence on anti-acid medications. Data analyzed by chi-square or Mann-Whitney tests are reported as mean +/- SEM.

RESULTS

Preoperative symptom duration, Johnson-DeMeester (JD) score, % time pH < 4, and reflux episodes were statistically similar in both treatment groups. The follow-up times for EG and LAS groups were 7.3 +/- 0.9 and 8 +/- 0.4 months, respectively. Of EG patients, 94% were available for follow-up, and all LAS patients had follow-up data. Overall, 66% of patients were satisfied with EG as compared to 93% after LAS (p = 0.1). Postoperative PPI/motility agent use was 32% for EG and 13% for LAS (p = 0.03). Identifiable causes of EG failure were premature procedure termination due to hypoxia or bleeding (three patients), intractable vomiting (two patients), and delayed gastric emptying (five patients). Three EG patients subsequently had LAS within 6 months of the procedure.

CONCLUSIONS

LAS offers greater reduction in medication use than EG, as well as more durable patient satisfaction. Benefits of EG may include short-term symptomatic improvement while considering definitive surgical management.

Preoperative factors predictive of complicated postoperative management after Roux-en-Y gastric bypass for morbid obesity

INTRODUCTION

This study was undertaken to determine preoperative predictive factors of complicated postoperative management after Roux-en-Y gastric bypass (RYGB) for morbid obesity.

METHODS

Between January 1999 and January 2002, 158 patients who underwent a RYGB received a standardized preoperative evaluation and data were collected prospectively. Complicated postoperative management was defined as patients requiring postoperative ICU admission for > or =48 h, or those needing transfer from the floor to the ICU. Patients with complicated management were compared with those in whom ICU admission was not necessary.

RESULTS

Twenty-three patients (14.5%) required prolonged ICU admission (mean stay of 6.3 +/- 1.7 days). After multivariate analysis, body mass index (BMI) >50 kg/m2, forced expiratory volume (FEV1) <80% predicted, previous abdominal surgeries, and abnormal EKG were found to be independently associated with an increased likelihood of complicated postoperative care.

CONCLUSION

BMI >50 kg/m2, FEV1 <80% predicted, previous abdominal surgeries, and abnormal EKG increase the likelihood of complicated postoperative management after RYGB for morbid obesity.

Can current technology be integrated to facilitate laparoscopic living donor hepatectomy?

BACKGROUND

Living donor hepatectomy (LDH) is a technically demanding procedure that is an alternative for providing livers for transplantation. Unlike liver resections for other pathology, LDH requires preservation of the major vessels and biliary tree. This study was performed to determine if current technology can be integrated to perform laparoscopic LDH.

METHODS

Six adult sheep underwent laparoscopic LDH of the left lateral segment under general anesthesia. Instruments utilized included standard dissecting instruments, ultrasound, ultrasonic dissectors, CUSA, the TissueLink Floating Ball, and endoscopic staplers.

RESULTS

LDH-harvested liver grafts were 44% of whole liver weight. Estimated blood loss was 300 cc. Warm ischemia time was 5-7 min. Grafts were delivered through 18-cm abdominal wounds. Major vessels and biliary anatomy were positively identified in the grafts.

CONCLUSIONS

Laparoscopic LDH can be performed with available technology. Theoretical advantages include reduced liver manipulation and smaller wound size.

Survival of bacterial isolates exposed to simulated Jovian trapped radiation belt electrons and solar wind protons

With missions to Jupiter, the spacecraft will be exposed for extended durations to solar wind radiation and the Jovian trapped radiation belt. This study is designed to determine the effect of these radiation environments on spacecraft bacterial isolates. The information can be used in the probability of contamination analysis for these missions. A bacterial subpopulation from Mariner Mars 1971 spacecraft (nine spore-forming and three non-spore-forming isolates) plus two comparative organisms, Staphylococcus epidermidis ATCC 17917 and a strain of Bacillus subtilis var. niger, were exposed to 2, 12, and 25 MeV electrons at different doses with simultaneous exposure to a vacuum of 1.3 x 10(-4) N m-2 at 20 and -20 degrees C. The radioresistance of the subpopulation was dependent on the isolate, dose and energy of electrons. Temperature affected the radioresistance of only the spore-forming isolates. Survival data indicated that spores were reduced approximately 1 log/1500 J kg-1 (10 J kg-1=1 krad), while non-spore-forming isolates (micrococci) were reduced 1.5-2 logs/1500 J kg-1 with the exception of an apparent radioresistant isolate whose resistance approached that of the spores. The subpopulation was found to be less resistant to lower energy than to higher energy electrons. The bacterial isolates were exposed to 3 keV protons under the same conditions as the electrons with a total fluence of 1.5 x 10(13) p cm-2 and a dose rate of 8.6 x 10(9) p cm-2 s-1. The results showed that only 20% of S. epidermidis and 45% of B. subtilis populations survived exposure to the 3 keV protons, while the mean survival of the spacecraft subpopulation was 45% with a range from 31.8% (non-spore-former) to 64.8% (non-spore-former). No significant difference existed between spore-forming and non-spore-forming isolates.