Indirect effects of decompression surgery on glycemic homeostasis in patients with type 2 diabetes mellitus and lumbar spinal stenosis

Background context: Lumbar spinal stenosis (LSS) patients with diabetes mellitus (DM) are presumed to experience difficulty when performing regular daily exercise, although such exercise is of paramount importance for glucose homeostasis and control. Therefore, decompression surgery, which can help patients perform regular physical activity, would have indirect positive effects on blood glucose control in LSS patients with DM.

Purpose: To evaluate the indirect effects of spinal surgery on hemoglobin A(1c) (HbA(1c)) levels in the patient with Type 2 DM and LSS.

Study design: Prospectively collected observational cohort data.

Patient sample: Patients with degenerative LSS and DM.

Outcome measures: The fasting total cholesterol (TC), fasting blood glucose (FBG), and HbA1c levels and visual analog scale (VAS) for back pain, VAS for leg pain, and Oswestry Disability Index (ODI).

Methods: According to the treatment methods, 31 and 37 patients were allocated to the surgical and conservative treatment groups, respectively. The HbA(1c), TC, and FBG levels and the ODI and VAS for back/leg pain were recorded for all patients before surgical and conservative treatments. At the first and second follow-up assessments after surgical or conservative treatment, the data were reassessed for all patients.

Results: In both groups, the VAS for back/leg pain and the ODI scores significantly decreased after surgical or conservative treatment. In the surgical treatment group, the HbA(1c) levels were significantly decreased at the first and second assessments after surgery, whereas the conservative treatment group did not show significant reductions in HbA(1c) levels at the first and second follow-up assessments. In both groups, the FBG levels did not differ between the initial and follow-up assessments. The TC levels were significantly decreased at the second follow-up assessment, only in the surgical treatment group. The amount of ODI score reduction correlated positively with the degree of HbA(1c) level reduction at the first follow-up assessment.

Conclusions: The present study demonstrates the reduction in HbA(1c) level in patients with DM and LSS after decompression surgery with or without fusion. We believe this reduction in the HbA(1c) level may be a result of increased physical activity, subsequent to successful surgical decompression of the cauda equina.