Nahid Hamoui

Sleeve Gastrectomy in the High-Risk Patient

Background: One of the surgical options available for the super-obese patient is the sleeve gastrectomy. We present results of this operation in a series of 118 patients. Methods: The charts of all patients who have had the sleeve gastrectomy performed were reviewed for demographic data, complications, weight, and nutritional parameters. Results: Median age was 47 years (16-70). Median BMI was 55 kg/m2 (37-108), with 73% of patients having a BMI ≥50 kg/m2. 41% of the patients were male. The operation was performed by laparotomy in all but three cases, which were performed laparoscopically. Median hospital stay was 6 days (3-59). There was one perioperative death (0.85%). 18 patients (15.3%) had postoperative complications. Median percent excess weight loss was 37.8% at 6 months, 49.4% at 12 months, and 47.3% at 24 months. Median follow-up was 13 months (1-66). At 1 year postoperatively, the percentage of patients with normal serum levels of albumin was 100%, hemoglobin 86.1%, and calcium 87.2%, compared to 98.1%, 85.6%, and 94.3% preoperatively. 6 patients requested conversion to a duodenal switch during the follow-up period; all left the hospital in 4-6 days without major complication. Conclusions: Although the sleeve gastrectomy does not result in as much weight loss as the duodenal switch or gastric bypass, it can be used as a stand-alone operation or as a bridge to more complex procedures in the high-risk super-obese patient.

Calcium Metabolism in the Morbidly Obese

Background: Morbidly obese patients are known to have abnormal calcium metabolism compared with the non-obese, but the clinical significance of this is unknown. Since surgical treatment of obesity may itself cause hyperparathyroidism, it is important to understand the preoperative physiology of these patients. Methods: 213 consecutive patients (M 37 : F 176, ages 21-68) presenting for surgical treatment of morbid obesity between October 2000 and June 2002 were prospectively evaluated. Preoperative levels of serum calcium corrected for albumin, alkaline phosphatase, parathyroid hormone (PTH), 25-hydroxyvitamin D, and 1,25-dihydroxyvitamin D were measured. We recorded the prevalence of abnormalities in study parameters and correlated them with PTH levels. Results: Hyperparathyroidism (PTH >65 pg/ml) was present in 25.0% of subjects. By contrast, abnormalities of serum calcium were rare. The prevalence of hypocalcemia was 3.5%, and of hypercalcemia was 0.5%. Only 4.3% of patients had increased levels of alkaline phosphatase. 21.1% of patients had abnormally low levels of 25-hydroxyvitamin D (median 15 ng/ml), and 23.1% had increased levels of 1,25-dihydroxyvitamin D (median 49 pg/ml). PTH was positively correlated with BMI (r=.30, P=<.001) and 25-dihydroxyvitamin D (r=.27, P=.01), and was negatively correlated with alkaline phosphatase (r=.21, P=.02). There was no correlation between PTH and calcium, 1,25-dihydoxyvitamin D, age, or sex. Conclusions: Parathyroid hormone levels are increased in the morbidly obese and are positively correlated with BMI. Recognition of preoperative hyperparathyroidism is important because of the risk of attributing postoperative hyperparathyroidism to the effects of surgery. Further studies are needed to elucidate the cause of elevated PTH in these patients.

Rhabdomyolysis of Gluteal Muscles Leading to Renal Failure: A Potentially Fatal Complication of Surgery in the Morbidly Obese

Background: Rhabdomyolysis is a well-known cause of renal failure and is most commonly caused by ischemia/reperfusion or crush injury. We describe a new cause of this syndrome in a series of 6 patients who underwent necrosis of the gluteal muscles after bariatric surgery, 3 of whom eventually died of renal failure. Methods: Potential etiologic factors were studied by comparing these patients with a consecutive series of 100 patients undergoing primary uncomplicated bariatric surgery during a 1-year period. Demographics, preoperative BMI, co-morbidities, duration of operation, and postoperative creatinine phosphokinase (CPK) levels. Results: All patients presented with an area of buttock skin breakdown initially diagnosed as a simple decubitus ulcer. All had extensive myonecrosis of the medial gluteal muscles requiring extensive debridement. 5 of the 6 patients were male, with median BMI 67 compared with a median BMI 55 in the control group (P=0.0022). The patients were on the operating-room table for a median of 5.7 hours compared with 4.0 in the control group (P=0.01). 3 of the 6 developed renal failure requiring dialysis, which was fatal in all. One other patient developed a transient elevation of BUN and creatinine which did not require dialysis. Since recognition of this pattern, we now routinely perform serial CPK measurements. Median CPK rise in uncomplicated patients was to 1,200 mg/dl (SD 450-9,000), while CPK in affected patients ranged from 26,000 to 29,000 IU/l. We now routinely add additional buttock padding in very obese patients and institute aggressive hydration and mannitol diuresis if CPK rises above 5,000. No cases have occurred in the past 18 months in 220 patients. Conclusions: This is an important and potentially fatal complication of bariatric surgery. Very obese male patients with prolonged surgery are at risk of gluteal muscle necrosis with consequent renal failure, which we hypothesize is due to pressure by the operating-table leading to rhabdomyolysis and the creation of a compartment syndrome. Prevention may be aided by attention to intraoperative padding and positioning, and by limiting the duration of the operation.

Long-term Outcome of Total Knee Replacement: Does Obesity Matter?

Background: Although arthritic complications are common in the obese, many surgeons are reluctant to perform joint replacements in this population. We compared outcomes of total knee arthroplasties (TKAs) in normal weight and obese patients. Methods: 30 TKAs in 21 obese patients with BMI 30-49 (Group A – mainly mildly and moderately obese) were compared to a matched group of 53 TKAs in 41 non-obese patients with BMI 16-29.9 (Group B). Outcome measures included the Knee Society Score (a composite of clinical and functional parameters), radiographic results, and the need for revision or reoperation. Results: Median follow-up was 11.3 years; no patients were lost to follow-up during this time. The Knee Society Score rose 92 points in Group A to a final score of 184, and 95 points in Group B to a score of 193. There was no statistical difference in Groups A and B between the improvement in scores or the final score achieved. Osteolysis rates were not significantly different between the 2 groups (5% vs 13%), nor were radiolucency rates (0% vs 9.7%). Median alignment was also similar in both groups (8.1° vs 8.0° valgus). 13.3% of Group A required reoperation while none required revision, and 13.2% of Group B required reoperation with 3.8% requiring revision. Survival rates were similar in both groups (71.4% vs 61.5%). Conclusions: Moderate obesity does not affect the clinical and radiologic outcome of TKA. However, TKA results in improved mobility, enhancing the success of subsequent weight loss therapy.

Surgical treatment of morbid obesity in schizophrenic patients.

Background: Newer antipsychotic medications have greatly improved the treatment of schizophrenia, but they are known to be associated with serious weight gain. Little is known about treatment of morbid obesity in this population. Methods: 5 patients with schizophrenia and morbid obesity were studied.Weight loss was compared with that achieved by 165 non-psychotic patients who also underwent bariatric surgery during a 1-year period. Results: 5 morbidly obese patients with schizophrenia underwent bariatric surgery between February 1999 and April 2003. All patients were well controlled on antipsychotics. The median BMI was 54 (51-70) and all had obesity-related co-morbities. All patients had been previously treated unsuccessfully with conservative methods of weight reduction. 3 patients had a duodenal switch operation, 1 patient had a sleeve gastrectomy, and 1 had conversion of a silastic ring gastroplasty to biliopancreatic diversion. All patients were maintained on their antipsychotic medications until 24 hours before surgery. Median percent excess weight loss at 6 months was comparable to that achieved in the control group. Conclusions: Good control of schizophrenia may be achieved by newer therapies but at the risk of weight gain. The results of bariatric surgery in such patients are comparable to those of non-psychotic morbidly obese patients. Further follow-up is needed, but the results are encouraging.

Quantitative, tissue-specific analysis of cyclooxygenase gene expression in the pathogenesis of Barrett's adenocarcinoma.

Cyclooxygenase (Cox-2) is implicated in the pathogenesis of many cancers including esophageal adenocarcinoma (EAC), whereas the role of the isoform Cox-1 in carcinogenesis is not well understood. To further elucidate the role of these factors in the development of EAC, we measured the gene expressions (mRNA levels) of Cox-2 and Cox-1 by real-time quantitative polymerase chain reaction (QRTPCR) in tissues from normal esophagus with and without erosive gastroesophageal reflux disease (GERD), Barrett’s esophagus (BE), dysplasia, adenocarcinoma, and in healthy gastric antrum. All tissues were purified by laser capture microdissection from endoscopic or surgical resection specimens. Median Cox-2 gene expression did not differ significantly among the esophageal control groups but was elevated 5-fold in BE, 8-fold in dysplasia and 16-fold in EAC compared to normal esophageal controls with no erosive GERD. Erosive GERD tissue had slightly higher median Cox-2 expression but Cox-2 expression in normal antrum was much higher than that in a normal esophagus, close to that of dysplasia. In contrast to that of Cox-2, Cox-1 expression was significantly decreased in all neoplastic tissues compared to normal controls. Cox-1 and Cox-2 expression varied over a wide range in the neoplastic tissues but over a relatively narrow range in the esophageal normal tissues. The occurrence of substantial alterations in Cox-1 and Cox-2 expression at the BE stage indicates that these are early events in the development of EAC. These results confirm the important role of Cox-2 amplification in the pathogenesis of esophageal adenocarcinoma, but the unexpected down-regulation of Cox-1 raises questions about its role in carcinogenesis.

Response of the lower esophageal sphincter to gastric distention by carbonated beverages

Gastroesophageal reflux disease often occurs in patients with normal resting pressure and length of the lower esophageal sphincter. Such patients often have postprandial reflux. The mechanism of postprandial reflux remains controversial. To further clarify this, we studied the effect of carbonated beverages on the resting parameters of the lower esophageal sphincter. Nine asymptomatic healthy volunteers underwent lower esophageal sphincter manometry using a slow motorized pull through technique after ingestion of tap water and carbonated beverages. Resting pressure, overall length, and abdominal length of the lower esophageal sphincter were measured. All carbonated beverages produced sustained (20 minutes) reduction of 30–50% in all three parameters of the lower esophageal sphincter. In 62%, the reduction was of sufficient magnitude to cause the lower esophageal sphincter to reach a level normally diagnostic of incompetence. Tap water caused no reduction in sphincter parameters. Carbonated beverages, but not tap water, reduce the strength of the lower esophageal sphincter. This may be relevant to the pathogenesis of gastroesophageal reflux disease, especially in Western society.

The Value of Pulmonary Function Testing Prior to Bariatric Surgery

Background: Pulmonary function tests (PFTs) are often abnormal in the morbidly obese and improve after bariatric surgery. Our aim was to determine the utility of obtaining preoperative PFTs in assessing postoperative risk. Methods: 146 consecutive patients undergoing open bariatric surgery were analyzed. Patients were divided into those who had postoperative complications (Group A, n=27) and those who did not (Group B, n=119). PFTs and BMI were compared between Groups A and B. PFT parameters are reported as the median percentage of age-matched controls. Results: Patients in Group A compared to Group B were heavier (BMI 58 vs 51 kg/m2, P=.001) and older (46 vs 40 years, P=.02) than those in group B. They had reduced forced vital capacity (80% vs 97%, P<.001) and forced expiratory volume in 1 second (84% vs 99%, P=.002). They also had reduced vital capacity (VC, 85% vs 102%, P<.001) and total lung capacity (89% vs 99%, P=.01). They had decreased maximal voluntary ventilation (93% vs 106%, P=.003). They had lower arterial pO2 (76 mmHg vs 85 mmHg, P=.001) and higher arterial-alveolar gradient (23 vs 17, P=.007). The strongest predictors of postoperative complications on multivariate analysis were reduced VC (RR 2.29 for each 10% decrease in VC, P=.0007) and age (RR 6.4 for age >40 years, P=.01). Conclusions: PFTs help to predict complications after bariatric surgery. The greatest reduction in VC may occur in patients with central obesity, reflecting increased intrabdominal pressure and diminished chest wall compliance.