The effect of surgical weight reduction on functional status in morbidly obese patients with low back pain

Background: Although low back (LBP) pain is not a life-threatening disease, it is a source of significant discomfort and disability and accounts for work absences. It has been shown previously that morbid obesity is associated with increased frequency of LBP and that surgical weight loss improves the symptomatology. However, there are no studies to quantitatively assess the exact degree of functional disability caused by severe obesity and the degree of improvement of LBP that follows weight loss from bariatric surgery. Methods: 29 morbidly obese candidates for bariatric surgery with LBP, weight 132.5 +/- 27 (mean +/- SD) kg and BMI 47.2 +/- 8.8 kg/m(2) were examined for their functional status using psychometric instruments specifically designed to objectively assess the patients' complaints. The preoperative scores were measured by a) visual analogue scales (VAS1, VAS2, VAS3), b) Roland-Morris disability questionnaire, c) Oswestry LBP disability questionnaire, and d) Waddell disability index, and were compared with the scores obtained by the same instruments 2 years after vertical banded gastroplasty. Results: The postoperative weight (92.3 +/- 19 kg) and BMI (32.9 +/- 6.3 kg/m(2)) of the 29 patients were significantly reduced (P<0.001). The improved functional disability scores were statistically significant: a) VAS1 1.59 +/- 1.86 (mean +/- SD) vs 0.32 +/- 0.64, P<0.001; b) VAS2 5.5 +/- 1.97 vs 2.14 +/- 1.88, P<0.001; c) VAS3 0.77 +/- 1.11 vs 0.09 +/- 0.29, P=0.006, d) Roland-Morris 7.89 +/- 5.11 vs 1.89 +/- 2.13, P<0.001; e) Oswestry 21.22 +/- 15.63 vs 5.61 +/- 7.51, P<0.001; f) Waddell 2.81 +/- 1.37 vs 0.56 +/- 0.72, P<0.001. Conclusions: Surgical weight loss significantly improves the degree of functional disability of morbidly obese patients suffering from LBP.