The effect of incidental dural lesions on outcome after decompression surgery for lumbar spinal stenosis: results of a multi-center study with 800 patients

Purpose: Incidental durotomy is one of the most common complications in lumbar spine surgery. There are conflicting reports whether a dural lesion is associated with an inferior outcome after lumbar decompression. This study analyzed the effect of incidental durotomy in this specific group of patients (Dura+) and compared the results with the remaining cohort without dural laceration (Dura-).

Methods: This prospective multi-center study included 800 patients with lumbar spinal stenosis who underwent exclusive decompression surgery. All procedures were performed as part of a multi-center investigation at three highly specialized spine clinics. Outcome measures (ODI, EQ5D, VAS_{back pain} and VAS_{leg pain}) were obtained preoperatively as well as 3 and 12 months after surgery. The effect of an incidental durotomy on the clinical outcomes was analyzed statistically between the two cohorts.

Results: An intraoperative dura lesion was recorded in 6.5 % (n = 52/800) of all cases. Both cohorts (Dura+ and Dura-) did not reveal any differences regarding patient demographics, risk factors, or co-morbidities at baseline. The length of the hospital stay was significantly longer for the Dura+ cohort (8.0 vs. 6.4 days; p < 0.01). After 12 months, the Dura- cohort demonstrated a significantly greater improvement in VAS_{back pain} in comparison to the Dura+ cohort (Δ21.4 vs. Δ7.2 points; p < 0.05). The differences for the remaining outcome measures were not statistically significant (p > 0.05).

Conclusions: The results of this study reveal that an incidental durotomy was associated with a significant increase in the patient's length of stay, and risk for re-intervention for the treatment of persisting CSF leakage. In contrast to previous reports which have investigated the effects of incidental durotomies on the clinical outcome after lumbar decompression surgery, our data further suggest a possible inferior outcome in terms of low back pain improvement in the Dura+ cohort, which became clinically apparent at the 12-month follow-up period. Future studies should investigate whether a more pronounced decompression required for adequate exposure and repair of a dural laceration may, ultimately, result in increased segmental instability and in clinically undesirable low back pain.