Gastric bypass surgery and effect on lower back pain

Apr 29 2008

The prevalence of both obesity and back pain in developing nations has reached alarming levels. According to recent statistics, more than one-third of U.S. adults - over 72 million people were obese in 2005-2006. Of these, 33.3 percent were men and 35.3 percent were women. Especially alarming is that obesity has not decreased among teenagers - the rates remain essentially unchanged in 2005-2006 from the 2003-2004 estimates, at 17 percent.

Obesity is defined as a body mass index (BMI) of 30 or greater. Unfortunately, the consequences of obesity on the human body can be devastating. It puts people at increased risk for many diseases and conditions, most notably: hypertension, Type 2 diabetes, coronary heart disease, stroke, some types of cancer, and gallbladder disease. There has been less research on the effects of obesity on the musculoskeletal system.

An estimated 75 to 85 percent of all Americans will experience some form of back pain during their lifetime. About 50 percent of all patients who suffer from an episode of low back pain will have a recurrent episode within one year. While it is well-known that that obese individuals experience a higher rate of hip and knee arthritis, little is known about its effect on lumbar spinal degeneration.

While obese patients with back pain are frequently advised to lose weight, the association between these medical conditions remains unproven. In order to assess the relationship of obesity to low back pain, research was undertaken on morbidly obese patients with low back pain who underwent gastric bypass surgery.

Researchers at the University of Southern California analyzed the outcome of 38 consecutive patients with low back pain who underwent bariatric surgery over a period of six months. The results of this study, Prospective Assessment of Axial Back Pain Symptoms before and after Bariatric Weight Reduction Surgery, will be presented by Paul Khoueir, MD, at 4:11 to 4:20 p.m. on Tuesday, April 29, 2008, during the 76th Annual Meeting of the American Association of Neurological Surgeons in Chicago. Co-authors are Mary Helen Black, MS, Peter F. Crookes, MD, Namir Katkhouda, MD, Howard S. Kaufman, MD, and Michael Y. Wang, MD.

Preoperative and postoperative data analyzed at 12 months included age, weight, body mass index (BMI), Back pain intensity - visual analog scale (VAS), quality of life questionaire (SF-36 Health Survey), and disbaility scores - Oswestry Disability Index (ODI). Paired t-tests and multiple regression techniques were used to assess differences in subject characteristics and outcomes. Additional patient demographics:

• Thirty patients were female and eight were male
• The age ranged from 20 to 68 years (mean 48.4 ± 10.1)

The following outcomes were noted postoperatively:

• There was a decrease in mean weight from 144.52 ± 41.21 kg preoperatively to 105.59 ± 29.24 postoperatively
• There was a decrease in BMI from 52.25 ± 12.61 kg/sq m preoperatively to 38.32 ± 9.66 postoperatively
• The mean reported pain scale decreased by 44 percent
• SF-36 physical health component increased by 58 percent
• SF-36 mental health increased by 6 percent
• Patient postoperative ODI score for physical disability decreased 24 percent

"Although past research has certainly shown that obesity is a risk factor for poorer outcome in patients undergoing spine surgery, this study provides evidence that substantial weight reduction following bariatric surgery results in moderate reductions in preexisting back pain within six months of weight loss. And this effect does not appear to be the result of the overall improvement associated with the patient's well being. While this initial research is promising, larger long-term trials are needed to prove the efficacy of this treatment," stated Dr. Khoueir.

Founded in 1931 as the Harvey Cushing Society, the American Association of Neurological Surgeons (AANS) is a scientific and educational association with more than 7,200 members worldwide. The AANS is dedicated to advancing the specialty of neurological surgery in order to provide the highest quality of neurosurgical care to the public. All active members of the AANS are certified by the American Board of Neurological Surgery, the Royal College of Physicians and Surgeons (Neurosurgery) of Canada or the Mexican Council of Neurological Surgery, AC. Neurological surgery is the medical specialty concerned with the prevention, diagnosis, treatment and rehabilitation of disorders that affect the entire nervous system, including the spinal column, spinal cord, brain and peripheral nerves.