Incidence, prognosis, and risk factors for bladder and bowel dysfunction due to incidental dural tears in lumbar microendoscopic surgery

Abstract

Background context: Despite the common occurrence of incidental dural tears, the incidence and prognosis of bladder and bowel dysfunction (BBD) due to incidental dural tears in lumbar spinal surgery are not well known because of the lack of reported cases.

Purpose: To analyze the incidence, prognosis, and risk factors for BBD after lumbar microendoscopic surgery with or without incidental dural tears.

Study design/setting: A retrospective cohort study.

Patient sample: We analyzed 2,421 patients who underwent lumbar microendoscopic surgery and investigated patients with BBD after an incidental durotomy during surgery.

Outcome measures: Patients were divided into three groups on the basis of dysuria and defecation disorders: severe BBD, mild BBD, and no BBD. The post void residual volumes before and after surgery were compared using an ultrasound bladder scanner or bladder catheterization after confirmation of urination. Bowel dysfunction was evaluated by subjective symptomatic deterioration and the increase in the frequency and duration of postoperative medical care.

Methods: Risk factors for BBD were analyzed using surgical video documentation to determine the dural tear site and cauda equina exposure from the dural sac. Patients with BBD were prospectively followed up for prognosis determination. The chi-square test was used to compare the incidence of BBD between patients with dural tears and those without. Propensity score-adjusted logistic regression analysis was performed to evaluate the effects of various factors on the incidence of postoperative BBD.

Results: The incidence of dural tears was 6.9% (168/2,421). The overall incidence of BBD was 3.0% (73/2,421), while the incidences of BBD (mild+severe BBD) and severe BBD due to incidental dural tears were 1.2% (30/2,421) and 0.8% (20/2,421), respectively. The incidence of BBD in patients with dural tears and those without tears was 17.9% [30/168] and 1.9% [43/2,253; p<.001]), respectively. BBD rates at 1 week, 1 month, 3 months, 6 months, and 1 year after surgery were 64.0%, 44.0%, 40.0%, 28.0%, and 13.6%, respectively. Logistic regression analysis revealed that the male sex (odds ratio [OR], 4.20), dural tears in the central area (OR, 10.15), and exposure of the cauda equina (OR, 51.04) were significant risk factors.

Conclusions: The incidence of dural tears in lumbar microendoscopic surgeries are associated with an increased incidence of BBD. The recovery rate for BBD due to incidental dural tears is generally good; however, some patients experience long-term symptoms. Clinicians should be aware that incidental dural tears with cauda equina exposure can increase the risk of BBD.

Keywords: Bladder and bowel dysfunction; Incidence; Incidental dural tear; Microendoscopic surgery; Prognosis; Risk factor.