Obesity Surgery, 15, 378-381 The Effect of Surgical Weight Reduction on Functional Status in Morbidly Obese Patients with Low Back Pain John Melissas, MD, FACS1; George Kontakis, MD2; Evaggelos Volakakis, MD1; Theodosis Tsepetis, MD2; Athanasios Alegakis, MD3; Alexander Hadjipavlou AG, MD, FACS2 Bariatric Unit, Departments of 1Surgical Oncology, 2Orthopaedics, and 3Biostatistics, Faculty of Medicine, University of Crete, Greece Background: Although low back (LBP) pain is not a lifethreatening 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/m2 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/m2) 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 Reprint requests to: Dr. John Melissas, 16 Sifaki Street, 71409 Heraklion, Crete, Greece. Fax: +30 2810 394834; e-mail: melissas@med.uoc.gr 378 Obesity Surgery, 15, 2005 improves the degree of functional disability of morbidly obese patients suffering from LBP. Key words: Morbid obesity, back pain, obesity-associated disorders, vertical banded gastroplasty, bariatric surgery Introduction Obesity is an increasingly prevalent major health problem, with several co-morbidities, including cardiovascular, metabolic, respiratory, malignancy, and musculoskeletal and joint problems.1-5 Abnormal mechanical loads placed on the spine of the obese patient appear to generate back symptoms,6-9 and despite views to the contrary,7,10 it is generally accepted that obesity is frequently correlated with low back pain (LBP).2,8,11,12 Although LBP is not a serious or even life-threatening disease, it constitutes a source of significant discomfort and disability, accounts for work absences, and has significant direct and indirect economic costs. However, there is no extended research on the functional status of morbidly obese patients suffering from LBP before and after surgical weight reduction.13 The present study uses well-established and validated measures of functional status14-17 in order to quantify the disability caused by LBP in morbidly obese patients and examine the exact degree of improvement resulting from weight loss following bariatric surgery. © FD-Communications Inc. Surgical Weight Reduction and Low Back Pain Material and Methods Among 50 morbidly obese patients before vertical banded gastroplasty (VBG), 29 patients (6 males and 23 females) with mean age±SD 37.4±11.2 years (range 18-56 years), suffered from LBP. The preoperative weight and body mass index (BMI) of this group and demographic characteristics are shown in Table 1. Patients with LBP were assessed for their functional status just before and 2 years after the bariatric operation using a) the Visual Analogue Scale, b) the Roland-Morris disability questionnaire, c) the Oswestry LBP disability questionnaire, and d) the Waddell disability index. Pre- and postoperative scores were compared. The Visual Analogue Scales (VAS)14 rates the intensity of pain sensation and the degree of discomfort experienced by the patients. Three horizontal scales grading from 0 (no pain) to 10 (most intense pain) are used in 1 cm increments. The patients were called to grade their pain immediately (VAS1), at its worst (VAS2), and at its best pattern (VAS3). scores of all sections are divided by the maximum score of 50. This average is then doubled to obtain the final percentage. A percentage between 0 and 20 represents minimal disability; 20%-40% means moderate disability; 40%-60% indicates severe disability; 60%-80% is a score for crippled patients; and 80%-100% indicates that the patient is either bedridden or magnifies the symptoms. Waddell Disability Index17 assesses 9 parameters: pain experienced in a sitting position, traveling, standing, walking and with heavy lifting; and the need (due to pain) for help to put on or remove footwear, sleep disturbance, life restriction and sexlife restriction. The maximum score is 9 points (one for each affirmative answer). A score >5 indicates significant disability. Statistical Analysis Continuous variables were expressed as mean ± standard deviation, while discrete variables were expressed as counts and proportions. Differences on scores and clinical parameters before and after surgical treatment were examined using a two-samples paired t-tests or the corresponding non-parametric Wilcoxon test when appropriate. Level of significance was set at P<0.05.18 Roland-Morris Disability Questionnaire15 consists of 24 yes-no questions, covering a range of daily activities, found to apply most widely to patients with back pain. This questionnaire is simple and reliably sensitive to changes of the clinical status. There is a positive correlation between elevated Roland-Morris score and the presence of chronic pain. Results Oswestry Low Back Disability Questionnaire16 is a disability screening test which consists of 10 sections, each containing 6 statements regarding functional levels that carry scores of 0 to 5. The total At 2 years postoperatively, the body weight of the 29 patients with LBP was 92.3±19.0 kg, significantly less than the preoperative body weight (P<0.001). The patients’ BMI before (47.2±8.8) and Table 1. Demographics of patients, weight and BMI before and 24 months after VBG Preoperative Patients with LBP Male Female Age (Mean ±SD), years Height (Mean ±SD), cm Weight (Mean ±SD), kg BMI (Mean ±SD), kg/m2 Postoperative 29 6 (20.7%) 23 (79.3%) 37.5 ± 11.2 167.7 ± 10.6 132.5 ± 27 47.2 ± 8.8 92.3 ± 19* 32.9 ± 6.3* *P<0.001. Obesity Surgery, 15, 2005 379 Melissas et al after (32.9±6.3) the operation was also reduced significantly (P<0.001) (Table 1). The functional disability scores using the above-mentioned instruments pre- and postoperatively are shown in Table 2. The differences on scores before and after surgical treatment, were statistically highly significant. Discussion The results of this study clearly show that weight reduction following bariatric surgery significantly improves all measurable parameters of functional disability due to LBP, and therefore positively affects and improves quality of life. In patients with LBP, in addition to the physical examination, the health-care provider requires a method to quantify the degree of disability and assess the quality of the treatment rendered.19,20 Thus, psychometric instruments (questionnaires, pain drawings, etc.) specifically designed to objectify the patients’ complaints – approaching the same subject from a different point of view – have been developed to measure clinical outcomes.14-17 These measures appear to be complementary and offer the best measurement of outcomes, especially in patients with LBP. Although these instruments are correlated with the cognitive state of the questioned subjects and assess perception rather than real ability, their usage is well established. 21-23 Several studies have shown a possible positive relation between excess body weight and risk for back disorders.2,8,11,12 However, other studies have failed to prove this positive association.7,10 In a previously published study by our Institution, we have shown an increased frequency of LBP in morbidly obese candiTable 2. The scores of functional status before and after surgical treatment Before Treatment (Mean ± SD) VAS1 1.59 ± VAS2 5.5 ± VAS3 0.77 ± Roland-Morris 7.89 ± Oswestry 21.22 ± Waddell 2.81 ± 380 1.86 1.97 1.11 5.11 15.63 1.37 Obesity Surgery, 15, 2005 After Treatment (Mean ± SD) 0.32 2.14 0.09 1.89 5.61 0.56 ± ± ± ± ± ± 0.64 1.88 0.29 2.13 7.51 0.72 P <0.001 <0.001 0.006 <0.001 <0.001 <0.001 dates for bariatric surgery compared to lean subjects. We have also noticed a significant improvement and even disappearance of the LBP symptoms, 2 years after surgical weight reduction in the majority of the patients.12 However, the exact degrees of functional disability caused by severe obesity, as well as the degree of improvement following weight loss, were not quantitatively assessed previously. In the present study, all patients had chronic back pain which was severe enough to interfere with activities of daily living such as sitting, traveling, standing, working, etc. This symptomatology also led to sleep disturbances, sex restriction, limitation in physical and social activities, and emotional problems. It is important to note that following surgical weight reduction, all the above quantifiable parameters were statistically significantly improved, thus positively affecting health-related quality of life. Taking into account that functional disability due to LBP is responsible for deterioration of the work ability and limitation of physical activity, it is obvious that the economic cost of severe obesity is not only limited to the direct cost of the disease, but also is a contributing factor to increases in health-related expenses (based on work absences and thus reduced productivity and physical inactivity from LBP).12,24 This cost is enormous. In Canada in the year 2001, it was estimated that the economic burden of physical inactivity for any reason was $5.3 billion, while the cost associated with obesity was $4.3 billion, from which $1.6 billion was required for direct health-care expenditure and $2.7 billion for indirect costs;24 these costs included the value of economic output lost because of illness, injury and related work disability, or premature death. The total economic costs of physical inactivity and obesity represented 2.6% and 2.2% respectively of the total health-care costs. Because most primary care physicians do not treat obesity,25 citing lack of time, resources, insurance, reimbursement and knowledge of effective intervention as significant barriers and because conservative management of morbid obesity is associated with a failure-rate as high as 98%,1,3,26 bariatric surgery currently remains the only effective treatment for severe obesity and its related co-morbidities, thus improving patients’ functional status, work capacity and quality of life, and minimizing health-related costs. Surgical Weight Reduction and Low Back Pain References 1. Melissas J, Christodoulakis M, Spyridakis M et al. Disorders associated with clinically severe obesity: significant improvement after surgical weight reduction. South Med J 1998; 91: 1143-8. 2. Leboeuf-Yde C, Kyvik KO, Bruun NH. Low back pain and lifestyle. Part II - Obesity. 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