Outcomes for trainees vs experienced surgeons undertaking laparoscopic antireflux surgery - is equipoise achieved?

BACKGROUND

There is a learning curve associated with laparoscopic antireflux surgery which has an impact on patient outcomes. It is unclear, however, whether this can be eliminated by supervision of early cases by experienced surgeons. The aim of this study was to evaluate the impact of training under supervision on outcomes for laparoscopic fundoplication.

METHOD

Patients undergoing primary laparoscopic antireflux surgery from 1995 to 2009 were identified from a prospective database. Patients were classified according to whether they were operated on by an experienced consultant or supervised trainee, and sub-categorised according to the presence of a very large hiatus hernia. A standardised questionnaire was used to assess outcomes for heartburn, dysphagia and satisfaction at 1 and 5 years follow-up. Outcomes for the study groups were compared.

RESULTS

One thousand seven hundred and ten patients underwent surgery; 1,112 were operated on by consultants and 598 by trainees. The peri-operative complication rate was not different between the groups, although in patients operated on by trainees, there were increased rates of endoscopic dilatation (9 vs. 5 % p = 0.014) and re-operation (9 vs. 6 %, p = 0.031), and a lower satisfaction rate (76 vs. 82 %, p = 0.044) within 5 years of surgery. All other outcomes were similar for trainees vs. consultants.

CONCLUSION

The learning curve for laparoscopic fundoplication had a small, but statistically significant, impact on patient outcomes, with slightly lesser outcomes when surgery was undertaken by trainees, even when supervised by experienced surgeons. Although the differences were not large, they raise questions about equipoise and highlight ethical dilemmas with teaching new generations of surgeons.

Twenty years of experience with laparoscopic antireflux surgery

BACKGROUND

There are few reports of large patient cohorts with long-term follow-up after laparoscopic antireflux surgery. This study was undertaken to evaluate changes in surgical practice and outcomes for laparoscopic antireflux surgery over a 20-year period.

METHODS

A standardized questionnaire, prospectively applied annually, was used to determine outcome for all patients undergoing laparoscopic fundoplication in two centres since commencing this procedure in 1991. Visual analogue scales ranging from 0 to 10 were used to assess symptoms of heartburn, dysphagia and satisfaction with overall outcome. Data were analysed to determine outcome across 20 years.

RESULTS

From 1991 to 2010, 2261 consecutive patients underwent laparoscopic fundoplication at the authors' institutions. Follow-up ranged from 1 to 19 (mean 7.6) years. Conversion to open surgery occurred in 73 operations (3.2 per cent). Revisional surgery was performed in 216 patients (9.6 per cent), within 12 months of the original operation in 116. There was a shift from Nissen to partial fundoplication across 20 years, and a recent decline in operations for reflux, offset by an increase in surgery for large hiatus hernia. Dysphagia and satisfaction scores were stable, and heartburn scores rose slightly across 15 years of follow-up. Heartburn scores were slightly higher and reoperation for reflux was more common after anterior partial fundoplication (P = 0.005), whereas dysphagia scores were lower and reoperation for dysphagia was less common (P < 0.001). At 10 years, satisfaction with outcome was similar for all fundoplication types.

CONCLUSION

Laparoscopic Nissen and partial fundoplications proved to be durable and achieved good long-term outcomes. At earlier follow-up, dysphagia was less common but reflux more common after anterior partial fundoplication, although differences had largely disappeared by 10 years.

Accuracy of PET-CT in predicting survival in patients with esophageal cancer

BACKGROUND

Positron emission tomography (PET) is an integral part of tumor staging for patients with esophageal cancer. Recent studies suggest a role for PET scan in predicting survival in these patients, but this relationship is unclear in the setting of neoadjuvant therapy. We examined pretreatment maximum standard uptake value (SUV(max)) of the primary tumor in patients treated with and without neoadjuvant therapy.

METHODS

All patients undergoing esophagectomy with a preoperative PET scan over a nine-year period (2001-2010) were identified from a prospectively maintained database. Positron emission tomography data were obtained from computers housing the original PET scans. Overall survival was correlated with SUV(max) of the primary tumor.

RESULTS

A total of 191 patients were identified, and 103 patients met inclusion criteria. Eighty-two had an adenocarcinoma (80%), and 21 (20%) had a squamous cell carcinoma. Fifty-seven (55%) patients received neoadjuvant therapy. In the surgery alone group, a SUV(max) of > 5.0 in the primary tumor was associated with poor prognosis [Hazard Ratio (HR) 0.32; p = 0.007], but this factor did not retain its significance on multivariate analysis (HR 0.65; p = 0.43). Pretreatment SUV(max) in patients who underwent neoadjuvant therapy was not significant in predicting overall survival (p = 0.10).

CONCLUSIONS

This study does not support the use of SUV(max) on pretreatment PET scans as a prognostic tool for patients with esophageal cancer, especially in those who have received neoadjuvant therapy. Lymph node status is a more accurate predictor of outcome, and efforts to improve pretreatment staging should focus on this factor.

Does the addition of a fundoplication improve outcomes for patients undergoing laparoscopic Heller's cardiomyotomy?

Laparoscopic Heller's cardiomyotomy is a well-established technique in the treatment of achalasia. However, the addition of a routine fundoplication as part of this procedure remains controversial. A best evidence topic in upper gastrointestinal surgery was written according to a structured protocol. The question addressed whether the addition of a fundoplication improved clinical outcomes. Two hundred and seven papers were found using the reported search and of these, 8 papers were identified using a pre-determined criteria as representing the best answer to this clinical question. There were 2 meta-analyses, 3 randomised controlled trials and 3 prospective series. The author, journal, date and country of publication, patient group, study type, relevant outcomes, results, and study weaknesses of these papers are tabulated. Review of the data shows that the rates of gastro-oesophageal reflux both on pH monitoring and symptom reporting are all reduced when an anti-reflux procedure is added to a Heller's cardiomyotomy. In terms of the choice of the anti-reflux procedure, comparison between the Dor anterior and Toupet posterior fundoplications do not show any obvious clinical differences, however dysphagia appears to be lower in those undergoing partial fundoplication as compared to a Nissen fundoplication.

Effect of sex on symptoms associated with gastroesophageal reflux

BACKGROUND

Previous research suggests that females have a poorer outcome than do males after surgery for gastroesophageal reflux.

OBJECTIVE

To evaluate reflux and esophageal symptoms in males and females in a community sample and in patients undergoing antireflux surgery.

DESIGN

Face-to-face interview.

SETTING

A South Australian community.

PARTICIPANTS

Random sample of 2973 individuals from the community and 2153 patients presenting for antireflux surgery.

MAIN OUTCOME MEASURES

In a random sample of 2973 individuals from the community, the prevalence of reflux and other esophageal symptoms was determined and compared with symptoms in 2153 patients presenting for antireflux surgery. Identical questions were used to assess frequency and severity of heartburn and dysphagia and medication use. Analog scales assessed heartburn and dysphagia (0 indicating no symptoms and 10, severe symptoms). Outcomes for males vs females were compared across both groups.

RESULTS

In the community, females were more likely to report heartburn, and when reported, symptom severity was higher. The prevalence of dysphagia was similar for males and females, although females reported higher dysphagia scores for solid foods. A similar proportion of males and females took antireflux medications. Females presenting for antireflux surgery were, on average, 7 years older than males, had a higher body mass index, and had higher heartburn and dysphagia symptom scores. At endoscopy, men were more likely to have ulcerative esophagitis and Barrett esophagus, and at surgery they were less likely to have a hiatal hernia.

CONCLUSIONS

Significant differences were noted between males and females in the frequency and severity of gastroesophageal reflux-associated symptoms in the community and in patients presenting for surgery. These might reflect differences in symptom perception, which explain previously reported better outcomes in men undergoing antireflux surgery.

An objective measurement of the build-up of auditory streaming and of its modulation by attention

Three experiments studied auditory streaming using sequences of alternating "ABA" triplets, where "A" and "B" were 50-ms tones differing in frequency by Δf semitones and separated by 75-ms gaps. Experiment 1 showed that detection of a short increase in the gap between a B tone and the preceding A tone, imposed on one ABA triplet, was better when the delay occurred early versus late in the sequence, and for Δf = 4 vs. Δf = 8. The results of this experiment were consistent with those of a subjective streaming judgment task. Experiment 2 showed that the detection of a delay 12.5 s into a 13.5-s sequence could be improved by requiring participants to perform a task on competing stimuli presented to the other ear for the first 10 s of that sequence. Hence, adding an additional task demand could improve performance via its effect on the perceptual organization of a sound sequence. The results demonstrate that attention affects streaming in an objective task and that the effects of build-up are not completely under voluntary control. In particular, even though build-up can impair performance in an objective task, participants are unable to prevent this from happening.

Sentinel lymph node biopsy in esophageal cancer: should it be standard of care?

INTRODUCTION

Sentinel node mapping is established in some superficial cancers but remains controversial in harder-to-access solid tumors. There are an increasing number of recent studies suggesting that isolated tumor cells have prognostic significance in predicting poor survival, in breast cancer, esophageal cancer, and others. It is for this reason that we have persevered with the sentinel lymph node concept in our esophagectomy cancer patients, and we report our results since 2008.

METHODS

Thirty-one of 32 consecutive patients underwent resection for invasive esophageal cancer along with sentinel lymph node retrieval (resection rate, 97%). Peritumoral injection of (99m)Tc antimony colloid was performed by upper endoscopy prior to the operation. A two-surgeon synchronous approach via a right thoracotomy and laparotomy was performed with a conservative lymphadenectomy. Sentinel lymph nodes were identified with a gamma probe both in and ex vivo, and sent off separately for three serial sections and immunohistochemistry with AE1/AE3.

RESULTS

The median patient age was 63.4 years (range, 45-75 years). Most patients (81%) had an adenocarcinoma, and 61% had received neoadjuvant therapy. At least one sentinel lymph node (median, 3) was identified in 29 of 31 patients (success rate, 94%). Sentinel nodes were present in more than one nodal station in 16 patients (55%). One false negative case led to a sensitivity of 90%. In 28 of 29 patients, the sentinel lymph node accurately predicted findings in non-sentinel nodes (accuracy, 96%).

CONCLUSIONS

Sentinel lymph node biopsy is both feasible and accurate in esophageal resections with conservative lymphadenectomy. It allows targeted serial sectioning and immunohistochemical studies of those nodes and should become standard of care in patients undergoing esophagectomy for esophageal cancer.

Post-fundoplication contrast studies: is there room for improvement?

OBJECTIVE

Since the mid-1990s, laparoscopic fundoplication for gastro-oesophageal reflux disease has become the surgical procedure of choice. Several surgical groups perform routine post-operative contrast studies to exclude any (asymptomatic) anatomical abnormality and to expedite discharge from hospital. The purpose of this study was to determine the accuracy and interobserver reliability for surgeons and radiologists in contrast study interpretation.

METHODS

11 surgeons and 13 radiologists (all blinded to outcome) retrospectively reviewed the contrast studies of 20 patients who had undergone a laparoscopic fundoplication. Each observer reported on fundal wrap position, leak or extravasation of contrast and contrast hold-up at the gastro-oesophageal junction (on a scale of 0-4). A κ coefficient was used to evaluate interobserver reliability.

RESULTS

Surgeons were more accurate than radiologists in identifying normal studies (specificity = 91.6% vs 78.9%), whereas both groups had similar accuracy in identifying abnormal studies (sensitivity = 82.3% vs 85.2%). There was higher agreement amongst surgeons than amongst radiologists when determining wrap position (κ = 0.65 vs 0.54). Both groups had low agreement when classifying a wrap migration as partial or total (κ = 0.33 vs 0.06). Radiologists were more likely to interpret the position of the wrap as abnormal (relative risk = 1.25) while surgeons reported a greater degree of hold-up of contrast at the gastro-oesophageal junction (mean score = 1.17 vs 0.86).

CONCLUSION

Radiologists would benefit from more information about the technical details of laparoscopic anti-reflux surgery. Standardised protocols for performing post-fundoplication contrast studies are needed.

Impact of ineffective oesophageal motility and wrap type on dysphagia after laparoscopic fundoplication

BACKGROUND

Laparoscopic 360° fundoplication is the most common operation for gastro-oesophageal reflux disease, but is associated with postoperative dysphagia in some patients. Patients with ineffective oesophageal motility may have a higher risk of developing postoperative dysphagia, but this remains unclear.

METHODS

From 1991 to 2010, 2040 patients underwent primary laparoscopic fundoplication for gastro-oesophageal reflux disease and met the study inclusion criteria; 343 had a 90°, 498 a 180° and 1199 a 360° fundoplication. Primary peristalsis and distal contraction amplitude during oesophageal manometry were determined for 1354 patients. Postoperative dysphagia scores (range 0-45) were recorded at 3 and 12 months, then annually. Oesophageal dilatations and/or reoperations for dysphagia were recorded.

RESULTS

Preoperative oesophageal motility did not influence postoperative dysphagia scores, the need for dilatation and/or reoperation up to 6 years. Three-month dysphagia scores were lower after 90° and 180° compared with 360° fundoplication (mean(s.e.m.) 8·0(0·6) and 9·8(0·5) respectively versus 11·9(0·4); P < 0·001 and P = 0·003), but these differences diminished after 6 years of follow-up. The incidence of dilatation and reoperation for dysphagia was lower after 90° (2·6 and 0·6 per cent respectively) and 180° (4·4 and 1·0 per cent) fundoplications than with a 360° wrap (9·8 and 6·8 per cent; both P < 0·001 versus 90° and 180° groups).

CONCLUSION

Tailoring the degree of fundoplication according to preoperative oesophageal motility by standard manometric parameters has no long-term impact on postoperative dysphagia. There is, however, a proportionate increase in short-term dysphagia scores with increasing degree of wrap, and a corresponding proportionate increase in dilatations and reoperations for dysphagia. These differences in dysphagia scores diminish with time.

Diffuse esophageal leiomyomatosis

Progressive dysphagia of unknown etiology may still provide a diagnostic challenge despite an increase in the number and quality of investigations available. We describe a 64-year-old man who presented with progressive dysphagia and weight loss. Following a number of investigations, a diagnosis of diffuse esophageal leiomyomatosis was made and the patient was treated appropriately.

Her-2/neu gene amplification in esophageal adenocarcinoma and its influence on survival

BACKGROUND

HER-2/neu (c-erbB-2, HER2) gene amplification and protein overexpression have been associated with poor prognosis in several solid tumors, including breast and gastric cancer. Its incidence and significance in esophageal adenocarcinoma is unknown.

MATERIALS AND METHODS

Tissue microarrays were successfully constructed from 89 paraffin-embedded archival specimens of esophageal adenocarcinomas for HER2 gene amplification by silver-enhanced in situ hybridization (SISH). No patients had undergone neoadjuvant therapy. Protein overexpression was tested with immunohistochemistry (IHC) using automated immunostaining (Ventana Benchmark). Incidence of HER2 positivity, correlation to clinicopathological variables in esophageal cancer patients, and concordance between SISH and IHC were determined.

RESULTS

True HER2 gene amplification was detected in 14 esophageal cancer specimens (16%), and 92% of those with high-level HER2 amplification showed positive HER2 protein overexpression. No significant associations were found among gene amplification and clinicopathological factors. The 5-year survival rates were 57% for esophageal cancer patients with HER2 amplification compared with 32% without, but the difference in overall survival was not significant (P = .37). The correlation between SISH and IHC was statistically significant (P < .0001).

CONCLUSION

While molecular targeting may be possible for approximately 16% of esophageal adenocarcinoma patients, HER2 oncogene amplification did not influence survival in this study.

Feasibility study of sentinel lymph node biopsy in esophageal cancer with conservative lymphadenectomy

INTRODUCTION

Lymphoscintigraphy and sentinel node mapping is established in breast cancer and melanoma but not in esophageal cancer, even though many centers have shown that occult tumor deposits in lymph nodes influence prognosis. We report our initial experience with lymphoscintigraphy and sentinel lymph node biopsy in patients undergoing resection for esophageal cancer.

METHODS

Sixteen of 17 consecutive patients underwent resection for invasive esophageal cancer along with sentinel lymph node retrieval (resection rate, 94%). Peritumoral injection of (99m)Tc antimony colloid was performed by upper endoscopy prior to the operation. A two-surgeon synchronous approach via right thoracotomy and laparotomy was performed with conservative lymphadenectomy. Sentinel lymph nodes were identified using a gamma probe both in vivo and ex vivo. Sentinel lymph nodes were sent off separately for serial sections and immunohistochemistry.

RESULTS

Median patient age was 60.4 years (range, 45-75 years). Fifteen were male, and thirteen had adenocarcinoma. At least one sentinel lymph node (median, 2) was identified in 14 of 16 patients (success rate, 88%). Sentinel nodes were present in more than one nodal station in five patients (31%). In all 14 patients, the sentinel lymph node accurately predicted findings in non-sentinel nodes (accuracy, 100%). Three patients with positive sentinel lymph nodes had metastases identified in non-sentinel nodes (sensitivity, 100%).

CONCLUSIONS

Sentinel lymph node biopsy is feasible in esophageal resection with conservative lymphadenectomy, and initial results suggest it is accurate in predicting overall nodal status. Further study is needed to assess impact on patient management and prognosis.

Outcome following surgery for squamous cell carcinoma of the oesophagus

INTRODUCTION

This study was undertaken to determine the outcomes of patients treated for squamous cell carcinoma (SCC) of the oesophagus.

METHODS

The study group consisted of 61 patients (median age: 64 years) with invasive SCC of the oesophagus who underwent resection between 1987 and 2007 in Adelaide, South Australia. Thirty-two (52%) were female. Survival data were available for all patients. The log rank test was performed to identify prognostic factors for survival.

RESULTS

The 5-year overall survival rate was 33% (median: 24 months). Of 61 patients, 42 (69%) received neoadjuvant therapy prior to surgery. The overall resection rate was 95%. Significant post-operative morbidity occurred in 47%, and the in-hospital mortality was 5% (30-day mortality: 3%). No overall survival benefit was seen in patients undergoing neoadjuvant therapy prior to surgical resection. However, patients who had a complete pathological response to neoadjuvant therapy had a better 5-year survival than patients who did not receive neoadjuvant therapy: 47% versus 30%, respectively.

CONCLUSIONS

Oesophagectomy following neoadjuvant therapy for SCC of the oesophagus can be performed with low perioperative mortality. A complete response to neoadjuvant therapy was followed by an improved survival outcome.

Risk prediction scores for postoperative mortality after esophagectomy: validation of different models

BACKGROUND

Different prediction models for operative mortality after esophagectomy have been developed. The aim of this study is to independently validate prediction models from Philadelphia, Rotterdam, Munich, and the ASA.

METHODS

The scores were validated using logistic regression models in two cohorts of patients undergoing esophagectomy for cancer from Switzerland (n = 170) and Australia (n = 176).

RESULTS

All scores except ASA were significantly higher in the Australian cohort. There was no significant difference in 30-day mortality or in-hospital death between groups. The Philadelphia and Rotterdam scores had a significant predictive value for 30-day mortality (p = 0.001) and in-hospital death (p = 0.003) in the pooled cohort, but only the Philadelphia score had a significant prediction value for 30-day mortality in both cohorts. Neither score showed any predictive value for in-hospital death in Australians but were highly significant in the Swiss cohort. ASA showed only a significant predictive value for 30-day mortality in the Swiss. For in-hospital death, ASA was a significant predictor in the pooled and Swiss cohorts. The Munich score did not have any significant predictive value whatsoever.

CONCLUSION

None of the scores can be applied generally. A better overall predictive score or specific prediction scores for each country should be developed.

Minimally invasive versus open esophagectomy for patients with esophageal cancer

BACKGROUND

Minimally invasive esophagectomy (MIE) compared with open esophagectomy (OE) has been shown to have clinical advantages, but selection bias is present.

METHODS

All patients undergoing MIE or OE for cancer between 1999 and 2007 were eligible for analysis. To minimize selection bias, only patients who also met the selection criteria for the thoracoscopic approach were included in the open esophagectomy group.

RESULTS

Fifty-six patients underwent MIE and 98 OE. No significant differences in demographics or pathologic data between groups occurred, with the exception of thoracic epidural analgesia (OE 98%, MIE 71.1%, p < 0.001), and neoadjuvant treatment (OE 50.5%, MIE 71.4%, p = 0.016). Morbidity and in-hospital death were not significantly different. Duration of surgery was longer in MIE (250 vs 209 minutes, p < 0.001) and blood loss less (320 mL vs 857 mL, p < 0.001). Intensive care unit stay was shorter in MIE (3.0 vs 6.8 days, p = 0.022). The relative risk (RR) for in-hospital death was 0.57 (p = 0.475) if the patients underwent MIE. After adjusting for thoracic epidural analgesia, the RR was 0.29 (p = 0.213) for the MIE group. The RR for surgical morbidity was 1.47 (p = 0.154) for patients undergoing MIE. Neoadjuvant treatment increased the RR for surgical morbidity to 1.78 (p = 0.028). No difference between the two groups concerning survival occurred.

CONCLUSIONS

The MIE is comparable with the OE. In MIE, neoadjuvant treatment increased the risk of surgical morbidity. Thoracic epidural analgesia in MIE reduced the risk of in-hospital death and should be considered for all patients undergoing esophagectomy.

Long-term outcomes of revisional surgery following laparoscopic fundoplication

Background

A small proportion of patients who have laparoscopic antireflux procedures require revisional surgery. This study investigated long-term clinical outcomes.

Methods

Patients requiring late revisional surgery following laparoscopic fundoplication for gastro-oesophageal reflux were identified from a prospective database. Long-term outcomes were determined using a questionnaire evaluating symptom scores for heartburn, dysphagia and satisfaction.

Results

The database search found 109 patients, including 98 (5·6 per cent) of 1751 patients who had primary surgery in the authors' unit. Indications for surgical revision were dysphagia (52 patients), recurrent reflux (36), mechanical symptoms related to paraoesophageal herniation (16) and atypical symptoms (five). The median time to revision was 26 months. Outcome data were available for 104 patients (median follow-up 66 months) and satisfaction data for 102, 88 of whom were highly satisfied (62·7 per cent) or satisfied (23·5 per cent) with the outcome. Patients who had revision for dysphagia had a higher incidence of poorly controlled heartburn (20 versus 2 per cent; P = 0·004), troublesome dysphagia (16 versus 6 per cent; P = 0·118) and a lower satisfaction score (P = 0·023) than those with recurrent reflux or paraoesophageal herniation.

Conclusion

Revisional surgery following laparoscopic fundoplication can produce good long-term results, but revision for dysphagia has less satisfactory outcomes.

Laparoscopic fundoplication in patients with a hypertensive lower esophageal sphincter

BACKGROUND

A small proportion of patients evaluated with manometry prior to a fundoplication have a high-pressure lower esophageal sphincter (LES). This paper examines the outcome of laparoscopic fundoplication for these patients.

MATERIAL AND METHODS

Between October 1991 and December 2006, 1,886 patients underwent primary laparoscopic fundoplication. Those with a high-pressure LES on preoperative manometry (LESP > or = 30 mm Hg at end expiration) were identified from a prospective database. Long-term outcomes were determined using analogue symptom scores (0-10) for heartburn, dysphagia, and patient satisfaction and compared to those of a matched control group.

RESULTS

Thirty patients (1.6%), nine men and 21 women, median age 51 years, had a hypertensive LES (mean, 36 mmHg; range, 30-55). Median follow-up after fundoplication was 99 (12-182) months. These patients had similar mean symptom scores to 30 matched controls for heartburn (2.3 vs. 2.2, P = 0.541), dysphagia (2.7 vs. 3.1, P = 0.539), and satisfaction (7.4 vs. 7.6, P = 0.546). Five patients required revision for dysphagia compared to no control patients (P = 0.005). These patients had a higher preoperative dysphagia score (6.6 vs. 3.1, P = 0.036).

CONCLUSION

Laparoscopic fundoplication can be performed with good long-term results for patients with reflux and a hypertensive LES. However, those with preoperative dysphagia have a higher failure rate.

Outcome for esophageal cancer following treatment with chemotherapy and radiotherapy but not esophagectomy: Nonsurgical treatment of esophageal cancer

Background:

More than 50% of patients with esophageal cancer are not suitable for surgery. The aim of this study was to analyze the outcome of patients undergoing standard nonsurgical treatment.

Methods:

Data of all patients undergoing nonsurgical treatment for esophageal cancer were identified from a prospective database.

Results:

Seventy-five patients were treated for localized disease, and 52 for metastatic disease at diagnosis. Except for age, which was higher in patients without metastases, there were no significant differences between the patients with vs. without metastatic disease. Kaplan–Meier analysis showed a median survival of 10.8 months for all patients. There was a significant difference in survival (p < 0.001) between the groups with versus without metastases, with median survival in the patients without metastases 13.6 months versus 6.5 months in patients with metastases. Patients undergoing nonsurgical treatment for localized disease had a five-year survival of 12%. No significant difference between adenocarcinoma and squamous cell carcinoma was identified. Subanalysis of patients who received chemoradiotherapy revealed similar results to the overall group of patients.

Conclusion:

In patients with localized disease at diagnosis, long-term survival can be achieved in some patients, whereas five-year survival is rare in patients who present with metastatic disease.

Detection of lymph node metastases in oesophageal cancer

Background

The importance of lymph node status in oesophageal cancer cannot be disputed. It is therefore surprising that no standardization exists in either terminology or methodology in lymph node analysis.

Methods

All online databases were searched to identify articles published from 1970 onwards. This was supplemented by hand searching references of retrieved articles.

Results and conclusion

Without accurate identification of lymph node metastases, patients cannot be staged properly, nor can best practice for the treatment of oesophageal cancer be determined. This review outlines the problem and proposes recommendations for standardization in terminology and methodology for the detection of lymph node metastases in oesophageal cancer.

Responses to interaural time delay in human cortex

Humans use differences in the timing of sounds at the two ears to determine the location of a sound source. Various models have been posited for the neural representation of these interaural time differences (ITDs). These models make opposing predictions about the lateralization of ITD processing in the human brain. The weighted-image model predicts that sounds leading in time at one ear activate maximally the opposite brain hemisphere for all values of ITD. In contrast, the π-limit model assumes that ITDs beyond half the period of the stimulus center frequency are not explicitly encoded in the brain and that such “long” ITDs activate maximally the side of the brain to which the sound is heard. A previous neuroimaging study revealed activity in the human inferior colliculus consistent with the π-limit. Here we show that cortical responses to sounds with ITDs within the π-limit are in line with the predictions of both models. However, contrary to the immediate predictions of both models, neural activation is bilateral for “long” ITDs, despite these being perceived as clearly lateralized. Furthermore, processing of long ITDs leads to higher activation in cortex than processing of short ITDs. These data show that coding of ITD in cortex is fundamentally different from coding of ITD in the brain stem. We discuss these results in the context of the two models.

Revisional bariatric surgery for failed restrictive procedures

BACKGROUND

Revisional bariatric surgery is increasing in frequency, but the morbidity and efficacy have not been well defined. The primary aim of this study was to determine the clinical efficacy with respect to weight loss, and associated morbidity, of revisional bariatric surgery in an academic university hospital bariatric surgery program.

METHODS

A retrospective review of all patients who underwent revisional bariatric surgery for failed primary restrictive procedures, including gastroplasty and gastric bypass, but not including gastric banding or malabsorptive procedures, during a 10-year period at a single university hospital was performed. The perioperative morbidity and long-term weight loss and clinical results were determined from the medical charts.

RESULTS

A total of 41 patients met the inclusion criteria. The primary bariatric procedures included vertical banded gastroplasty in 20 and Roux-en-Y gastric bypass in 21. The indications for revisional surgery included poor weight loss, weight regain, and various technical problems, including anastomotic stenosis and ulcer. The major morbidity rate was 17%. No patients died. The weight loss results varied depending on the indication for the revisional surgery and reoperative solution applied. The resolution of technical problems was achieved in all patients.

CONCLUSION

Revisional bariatric surgery can be performed with minimal mortality, albeit significant morbidity. The efficacy with respect to weight loss appeared acceptable, although the results were not as good as those after primary bariatric surgery. The analysis of patient subsets stratified by surgical history and revisional strategy provided important insights into the mechanisms of failure and efficacy of different revisional strategies.

Improved quality of life after bilateral laparoscopic adrenalectomy for Cushing's disease: a 10-year experience

OBJECTIVE

To determine long-term quality of life after bilateral adrenalectomy for persistent Cushing's disease after transsphenoidal pituitary tumor resection.

SUMMARY BACKGROUND DATA

Bilateral adrenalectomy for symptomatic relief of persistent hypercortisolism appears to be an effective treatment option. However, few studies have examined long-term outcomes in this patient population.

METHODS

Retrospective review of 39 patients treated by bilateral laparoscopic adrenalectomy for Cushing's disease from 1994 to 2004. Patients completed a follow-up phone survey, including our Cushing-specific questionnaire and the SF-12v2 health survey. Patients then refrained from taking their steroid replacement for 24 hours, and serum cortisol and ACTH levels were measured.

RESULTS

Three patients died at 12, 19, and 50 months following surgery from causes unrelated to adrenalectomy. The remaining 36 patients all responded to the study questionnaire (100% response rate). Patients were between 3 months and 10 years post-adrenalectomy. We had zero operative mortalities and a 10.3% morbidity rate. Our incidence of Nelson's syndrome requiring clinical intervention was 8.3%; 89% of patients reported an improvement in their Cushing-related symptoms, and 91.7% would undergo the same treatment again. Twenty of 36 (55%) and 29 of 36 (81%) patients fell within the top two thirds of the national average for physical and mental composite scores, respectively, on the SF-12v2 survey. An undetectable serum cortisol level was found in 79.4% of patients.

CONCLUSIONS

Laparoscopic bilateral adrenalectomy for symptomatic Cushing's disease is a safe and effective treatment option. The majority of patients experience considerable improvement in their Cushing's disease symptoms, and their quality of life equals that of patients initially cured by transsphenoidal pituitary tumor resection.

Recurrent heartburn after laparoscopic fundoplication is not always recurrent reflux

INTRODUCTION

A small cohort of patients present after antireflux surgery complaining of recurrent heartburn. Many of these patients have been empirically recommenced on proton pump inhibitors.

OBJECTIVE

The aim of this study was to determine whether patients with symptoms that suggest recurrent reflux had objective evidence of reflux, and to determine predictors of recurrent reflux.

METHODS

We identified all patients from an existing database who had undergone pH monitoring for "recurrent heartburn" after fundoplication. These patients were then cross-referenced to another database, which recorded the outcomes for patients who had undergone a laparoscopic fundoplication. Patients complaining of dysphagia or other problems without heartburn were excluded from analysis.

RESULTS

Seventy-six patients were identified who met the inclusion criteria. Fifty-six (74%) of these had a normal 24-h pH study. Thirty-five patients (63%) with a normal pH study were on medication for heartburn at the time of referral. Three factors were found to be associated with an abnormal 24-h pH study: a partial fundoplication (P = 0.039), onset of symptoms 6 months or more after surgery (P < 0.001), and a good symptom response when antireflux medication was recommenced (P = 0.015).

CONCLUSIONS

Not all patients complaining of recurrent heartburn after fundoplication have evidence of abnormal reflux. Objective evidence of abnormal esophageal acid exposure should be confirmed before recommencing antireflux medication.

Representation of interaural time delay in the human auditory midbrain

Interaural time difference (ITD) is a critical cue to sound-source localization. Traditional models assume that sounds leading at one ear, and perceived on that side, are processed in the opposite midbrain. Using functional magnetic resonance imaging we demonstrate that as the ITDs of sounds increase, midbrain activity can switch sides, even though perceived location remains on the same side. The data require a new model for human ITD processing.

Clinical review: Healing in gastrointestinal anastomoses, Part II

Complications arising from gastrointestinal anastomosis failures are a major source of morbidity and mortality. This review examines the effects of local blood flow on anastomotic healing, and discusses strategies for improving perfusion. Disruption of blood supply plays a significant role in the development of anastomotic leakage. Several methods have been suggested to improve perfusion. Omental pedicles have been employed as buttresses to promote angiogenesis, but efficacy in preventing anastomotic dehiscence has not been established. The administration of exogenous pharmacologic agents (such as vascular endothelial growth factor) is another potential strategy, although the oncological safety of this approach has been questioned. Two techniques which show promise in reducing anastomotic leakage rates include the vascular augmentation of grafts at risk for ischemia (supercharging) and ischemic conditioning (utilizing the delay phenomenon). Further studies of these strategies are needed to establish their efficacy and safety for routine use in gastrointestinal anastomoses.

Clinical review: Healing in gastrointestinal anastomoses, part II

Complications arising from gastrointestinal anastomosis failures are a major source of morbidity and mortality. This review examines the effects of local blood flow on anastomotic healing, and discusses strategies for improving perfusion. Disruption of blood supply plays a significant role in the development of anastomotic leakage. Several methods have been suggested to improve perfusion. Omental pedicles have been employed as buttresses to promote angiogenesis, but efficacy in preventing anastomotic dehiscence has not been established. The administration of exogenous pharmacologic agents (such as vascular endothelial growth factor) is another potential strategy, although the oncological safety of this approach has been questioned. Two techniques which show promise in reducing anastomotic leakage rates include the vascular augmentation of grafts at risk for ischemia (supercharging) and ischemic conditioning (utilizing the delay phenomenon). Further studies of these strategies are needed to establish their efficacy and safety for routine use in gastrointestinal anastomoses.

Clinical review: Healing in gastrointestinal anastomoses, Part I

Gastrointestinal healing is a topic rarely reviewed in the literature, yet it is of paramount importance to the surgeon. Failure of anastomotic healing may lead to life-threatening complications, additional surgical procedures, increased length of stay, increased cost, long-term disability, and reduced quality of life for the patient. The goal of this article is to review the biological response to wounded tissue, to outline discrete differences between skin and gastrointestinal healing, to discuss local and systemic factors important to gastrointestinal healing, and to compare methods of measuring collagen content and strength of the newly formed anastomosis. Part II of this review will focus on techniques and therapies available to optimize anastomotic healing.

Incidence of perioperative stroke after neck dissection for head and neck cancer: a regional outcome analysis

OBJECTIVE

To determine the incidence of perioperative stroke in patients undergoing a neck dissection.

SUMMARY BACKGROUND DATA

The incidence of perioperative stroke in non-head and neck surgery is between 0.08 and 0.2%. In contrast, a critical review of the literature identified 2 studies stating the incidence of perioperative stroke in head and neck surgery to be 3.2% and 4.8%. The implications of these results are significant because they suggest a potential need for preoperative screening and/or intervention for carotid artery pathology.

METHODS

This historical cohort study was conducted using discharge data for all neck dissections performed in a geographically-defined health region in Alberta, Canada, from 1994 to 2002. Subjects were selected for study if they had an assigned ICD-9CM procedure code for a neck dissection at one of the region's 3 adult-care hospitals. Our main outcome measure was perioperative stroke.

RESULTS

Patients (n = 499) were identified as having had a neck dissection (mean age 56.5 +/- 15.3 SD, 65.3% male). Seven patients had ICD-9CM codes for postoperative central nervous system complications (incidence of 1.4%). However, on chart review, only one had had a true perioperative stroke corresponding to an incidence of 0.2% (95% confidence interval 0.01, 1.12). No missed strokes were found in a confirmatory random review of 10% of charts.

CONCLUSIONS

The incidence of perioperative stroke in this study is significantly lower than that previously stated in the literature. This suggests that preoperative screening and/or intervention for carotid artery disease may not be necessary in this patient population.

Perioperative stroke occurring in patients who undergo neck dissection for head and neck cancer: unanswered questions

Stroke represents a major cause of disability among middle-aged and elderly people. Carotid artery stenosis is an important risk factor for stroke and is prevalent in elderly men with hypertension, diabetes mellitus, and those who smoke or have atherosclerotic disease, or both. Patients who undergo neck dissection for head and neck cancer may have some or all of the above characteristics and may experience surgical manipulation of the carotid arteries. This combination of medical and surgical factors may predispose such patients to perioperative stroke. A critical review of the literature was completed to determine the incidence of stroke perioperatively in patients undergoing a neck dissection for head and neck cancer. We found 2 studies that quoted the risk of stroke to be between 3.2% and 4.8%. The implications of these results are significant because they suggest a need for preoperative screening (with Doppler ultrasonography) or intervention (with carotid endarterectomy), or both. However, the quality of these 2 studies is such that future research is first needed to define the rate of stroke in head and neck surgery.

Comparison of an amorphous silicon/cesium iodide flat-panel digital chest radiography system with screen/film and computed radiography systems--a contrast-detail phantom study

Flat-panel (FP) based digital radiography systems have recently been introduced as a new and improved digital radiography technology; it is important to evaluate and compare this new technology with currently widely used conventional screen/film (SF) and computed radiography (CR) techniques. In this study, the low-contrast performance of an amorphous silicon/cesium iodide (aSi/Csl)-based flat-panel digital chest radiography system is compared to those of a screen/film and a computed radiography system by measuring their contrast-detail curves. Also studied were the effects of image enhancement in printing the digital images and dependence on kVp and incident exposure. It was found that the FP system demonstrated significantly better low-contrast performance than the SF or CR systems. It was estimated that a dose savings of 70%-90% could be achieved to match the low-contrast performance of the FP images to that of the SF images. This dose saving was also found to increase with the object size. No significant difference was observed in low-contrast performances between the SF and CR systems. The use of clinical enhancement protocols for printing digital images was found to be essential and result in better low-contrast performance. No significant effects were observed for different kVps. From the results of this contrast-detail phantom study, the aSi/CsI-based flat-panel digital chest system should perform better under clinical situations for detection of low-contrast objects such as lung nodules. However, proper processing prior to printing would be essential to realizing this better performance.

Steady-state kinetic characterization of substrates and metal-ion specificities of the full-length and N-terminally truncated recombinant human methionine aminopeptidases (type 2)

The steady-state kinetics of a full-length and truncated form of the type 2 human methionine aminopeptidase (hMetAP2) were analyzed by continuous monitoring of the amide bond cleavage of various peptide substrates and methionyl analogues of 7-amido-4-methylcoumarin (AMC) and p-nitroaniline (pNA), utilizing new fluorescence-based and absorbance-based assay substrates and a novel coupled-enzyme assay method. The most efficient substrates for hMetAP2 appeared to be peptides of three or more amino acids for which the values of k(cat)/K(m) were approximately 5 x 10(5) M(-1) min(-1). It was found that while the nature of the P1' residue of peptide substrates dictates the substrate specificity in the active site of hMetAP2, the P2' residue appears to play a key role in the kinetics of peptidolysis. The catalytic efficiency of dipeptide substrates was found to be at least 250-fold lower than those of the tripeptides. This substantially diminished catalytic efficiency of hMetAP2 observed with the alternative substrates MetAMC and MetpNA is almost entirely due to the reduction in the turnover rate (k(cat)), suggesting that cleavage of the amide bond is at least partially rate-limiting. The 107 N-terminal residues of hMetAP2 were not required for either the peptidolytic activity of the enzyme or its stability. Steady-state kinetic comparison and thermodynamic analyses of an N-terminally truncated form and full-length enzyme yielded essentially identical kinetic behavior and physical properties. Addition of exogenous Co(II) cation was found to significantly activate the full-length hMetAP2, while Zn(II) cation, on the other hand, was unable to activate hMetAP2 under any concentration that was tested.

The therapeutic potential of advances in cysteine protease inhibitor design

Cysteine proteases are attracting increased attention for therapeutic intervention by inhibitors because of an increased recognition of specific processing functions in both mammals and microbes. New advances in inhibitor design have been made for both reversible and irreversible classes. Reversible inhibitors may incorporate a covalent bond formation that can contribute an element of selectivity relative to serine protease inhibition. Ketones of low intrinsic reactivity are especially attractive agents, with potential for chronic therapeutic use. Effectively irreversible inhibition can be achieved with slow or single turnover substrates. This approach eliminates any reactivity toward non-enzyme nucleophiles. Only mechanistically related enzyme targets will be irreversibly blocked in an in vivo setting, thereby resulting in a safer type of inhibitor.

Performance analysis of a new semiorthogonal spline wavelet compression algorithm for tonal medical images

Lossy image compression is thought to be a necessity as radiology moves toward a filmless environment. Compression algorithms based on the discrete cosine transform (DCT) are limited due to the infinite support of the cosine basis function. Wavelets, basis functions that have compact or nearly compact support, are mathematically better suited for decorrelating medical image data. A lossy compression algorithm based on semiorthogonal cubic spline wavelets has been implemented and tested on six different image modalities (magnetic resonance, x-ray computed tomography, single photon emission tomography, digital fluoroscopy, computed radiography, and ultrasound). The fidelity of the reconstructed wavelet images was compared to images compressed with a DCT algorithm for compression ratios of up to 40:1. The wavelet algorithm was found to have generally lower average error metrics and higher peak-signal-to-noise ratios than the DCT algorithm.