Predictive factors for rhabdomyolysis after bariatric surgery.

BACKGROUND: Prevalence of obesity is increasing internationally. Obesity is also incriminated in the development of postoperative rhabdomyolysis (RML). Its major risk is the development of renal failure which is associated with high mortality. The aim of this study was to determine the risk factors for RML in patients undergoing bariatric surgery.
METHODS: Over a 12-month period, 49 consecutive patients were studied. They underwent gastric banding (n=32) or intestinal or gastric bypass (n=17) for morbid obesity (BMI >40 kg/m(2)). Surgery was performed in the supine position with a lumbar pad placed for intestinal shunt. The duration of surgery, persistent postoperative muscular pain, and pre- and postoperative creatine kinase (CK) were recorded. RML was defined as postoperative CK >1000 IU. L(-1) (5 times the normal value). Patients were retrospectively divided into 2 groups according to the presence or not of RML. In order to assess the role of BMI, it was decided to conduct an additional analysis in a group of consecutive non-obese patients who were matched for other risk characteristics.
RESULTS: In the 49 patients included in the study 13 developed RML (26.5%). Surgery >4 hours, presence of diabetes and patient ASA physical status III or IV were identified as factors associated with higher risk of RML. In the matched group (9 patients), no one developed postoperative RML.
CONCLUSIONS: After surgery for obesity, the risk of RML increases with prolonged surgery (>4 hours) and in diabetic obese patients with BMI >40 kg/m(2). In such patients, CK could be systematically measured to verify the presence of muscle injuries.