Decompression Surgery Indirectly Improves Glycemic Control in Patients with Diabetes and Lumbar Spinal Stenosis
Patients with type 2 diabetes mellitus (DM) had significant reductions in hemoglobin A1C levels following decompression surgery for the treatment of lumbar spinal stenosis, according to a prospective cohort study published online ahead of print in The Spine Journal. The authors believe this is an indirect effect of increased exercise level in patients following successful decompression surgery. Though many studies exist showing the effects of DM on spine surgical outcomes, this is the first study to show the effects of lumbar stenosis surgery on DM.
The study involved 68 patients aged 45 to 80 years (median age, 68 years) with type 2 diabetes mellitus and degenerative lumbar spinal stenosis. Thirty-one patients elected to undergo decompression surgery with (n=10) or without fusion (n=21) because of chronic leg/back pain and walking intolerance due to neurogenic claudication that was unresponsive to conservative treatments. The remaining 37 patients received conservative treatment with medication, physical therapy, and epidural steroid injection.
Follow-up was conducted at two points: 3 to 5 month after surgery or conservative treatment and again at 6 to 8 months. The primary outcome measures were the HgA1c levels, as well as the Oswestry Disability Index (ODI) and visual analog scale (VAS).
At baseline, the surgery group had significantly higher scores on VAS for leg pain (7.65 vs. 6.10; P=0.35) and on the ODI (49.24 vs. 38.26; P=0.028) compared with the conservative treatment group, but had similar scores on a VAS for back pain (6.65 and 6.28, respectively) and A1C level (7.20% and 7.09%, respectively).
Improvements in Hemoglobin A1C levels Found in Surgical Group
Significant decreases in VAS scores for back and leg pain as well as scores on the Oswestry Disability Index were found in both groups at follow-up assessments (Table). A significant decrease in A1C level was found in the surgery group at both the first and second follow-up assessment, but not in the conservative treatment group at either assessment.
A1C, hemoglobin A1C; ns, not significant; ODI, Oswestry Disability Index; VAS, visual analog scale
Total cholesterol levels decreased significantly only in the surgical treatment group at the second follow-up assessment. No change in fasting blood glucose levels was found in either group.
Improved Disability Scores Were Linked to Improved Glycemic Control
Improvement in Oswestry Disability Index score was positively correlated with the degree of improvement in A1C level at the first follow-up assessment in the surgery group (P=0.015).
“This finding suggests that increased physical activity resulting from the alleviation of leg and back pain consequent to spinal surgery would be associated with reduced A1C levels in patients with diabetes mellitus and lumbar spinal stenosis,” the authors noted. The improvements in disability and back/leg pain in the conservative treatment group were smaller in comparison with the changes in the surgery group, which may explain why the improvements in pain in the conservative group were not linked to improved glycemic control, the authors suggested. Another possibility is that spinal surgery may alter hormone levels, such as cortisol, which may modulate A1C levels, they added.