Does extreme weight loss after bariatric surgery alter spinopelvic parameters and ameliorate back pain? A retrospective case study.

Objectives: The aim of this study was to evaluate the effect of extreme weight loss on low back pain and spinopelvic parameters.

Patients And Methods: A total of 45 patients (11 males, 34 females; mean age: 40.2±9.4 years; range, 18 to 57 years) who had bariatric surgery between January 2018 and December 2021 were retrospectively analyzed. Radiological spinopelvic parameters including lumbar lordosis (LL), pelvic incidence (PI), spinopelvic harmony (when PI is within LL±10°), pelvic tilt (PT) and sacral slope (SS) were evaluated pre- and postoperatively. Clinical outcomes were assessed using the Visual Analog Scale-Back Pain (VAS-BP) and Oswestry Disability Index (ODI).

Results: The mean BMI loss at the end of the first year after surgery was 28.1±6.7% (range, 21 to 36%). The mean PI was 55.75°±12.47° preoperatively and 53.64°±11.86° at one year and the difference was -3.10°±5.25 (p=0.02), 1.10°±4.95° for PT (p=0.46), -2,70°±3.50° for SS (p<0.001), and 3.1±6.55 for LL (p<0.001). At one year, spinopelvic harmony remained unchanged in 31 patients, nine patients regained harmony, and was lost in five patients who had previously. No significant correlation between alterations in spinopelvic alignment and ODI scores was shown (p<0.05). The mean VAS-BP score was 40±30 mm preoperatively, and 20±3.5 mm postoperatively, indicating a difference of -39±29.5 (p<0.001). The mean ODI was 34.71±20.87 preoperatively, and 16±24 postoperatively, indicating a difference of -15±13 (p<0.001). Subgroup analyses showed that the change in SS was more pronounced with regard to PT change, particularly in young and female patients with >10 kg/m reduction in BMI (p<0.001).

Conclusion: Weight loss after bariatric surgery improves lower back pain leading to changes in PT without affecting SS and altering PI.