Lumbar Spine Fusion in Obese and Morbidly Obese Patients

Rahul Vaidya, MD, FRCSC; Julia Carp, BS; Stephen Bartol, MD, FRCSC; Nicole Ouellette, RN; Sandra Lee, DO; Anil Sethi, MD


Spine. 2009;34(5):495-500. 

In This Article

Abstract and Introduction


Study Design: Single-center retrospective study.
Objective: The aim of the study was to compare the surgical experience, clinical outcomes, and effect on body weight between obese and morbidly obese patients undergoing lumbar spine fusion surgery.
Summary of Background Data: Obese and morbidly obese patients undergoing spinal fusion surgery are a challenge to the operating surgeon. Only few reports are available on the perioperative data in this group of patients. Further, it is unknown if the degree of obesity has an effect on the surgical experience and clinical outcomes including body weight.
Methods: A retrospective study of 63 patients undergoing lumbar spinal fusion was carried out. The main inclusion criteria were a body mass index (BMI) equal to or greater than 30. Information recorded included surgical set-up time, surgical time, blood loss, American Association of Anesthesiologists score, and surgical complications. At follow-up, the Oswestry Disability Index and visual analog scale for back and leg pain were recorded along with a pain diagram and radiographic evaluation.
Results: The obese group had lower American Association of Anesthesiologists scores. The surgical time was dependent on the number of levels fused and was independent of the BMI. Blood loss during surgery was marginally greater in the obese patients. Neither group showed significant change in weight and BMI. Clinical outcomes showed improvement in visual analog scale for back and leg pain with some improvement in Oswestry scores and were independent of the BMI of the patient. The incidence of postoperative complications was significant in 45% of morbidly obese and 44% of obese patients.
Conclusion: Obese and morbidly obese patients have multiple comorbidities, and the spinal surgeon should be prepared to encounter perioperative complexities. Operative times are longer in comparison with normal weight patients with a higher incidence of postoperative complications. No weight loss occurs after spinal surgery.


The prevalence of obesity has reached epidemic proportions in the United States.[1,2,3] The definition of obesity is having a body weight that is 20% greater than the desirable body weight and having an excess of body fat that frequently results in significant impairment of health.[4,5] Obesity is commonly defined in terms of body mass index (BMI), which takes into account body weight and height. The National Institutes of Health has released guidelines on the classification of obesity.[6,7] Patients with a BMI of 30 to 39 with no significant comorbidity were considered obese. Morbidly obese patients had a BMI of 35 to 39 with a significant comorbidity or a BMI of 40 or greater. The presence of a significant comorbidity included having any one of the following 13 disorders: hypertension, diabetes, anticoagulation, asthma/bronchitis, hyperlipidemia, thyroid disease, psychiatric disorder, angina, alcohol consumption, shortness of breath, sleep apnea, and myocardial infarction.[7]

Spine surgery in the obese is challenging as a result of difficulties in anesthesia, intravenous access, and positioning of the patient, as well as due to the procedure itself.[8] The number of obese and morbidly obese patients requiring spinal surgery is on the rise. Thus, special treatment plans and considerations in the care of these patients are necessary before surgery.[4] Many patients in our study were unable to lose weight because of their inability to exercise. Several of these patients had been denied bariatric surgery due to chronic low back pain and symptoms of depression. These patients underwent spinal surgery with an objective of improving pain and function leading to a possible weight reduction. A statistically significant relationship has been reported between obesity and the incidence of perioperative complications.[9] An earlier study has also compared surgical outcomes between obese and normal weight controls during spine surgery.[10] However, it is not clear from previous reports if the perioperative behavior of patients is dependent on the degree of obesity. The purpose of this report is to compare the surgical experience, clinical outcomes, and effect on body weight between obese and morbidly obese patients undergoing lumbar spine fusion surgery.


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