Closed drainage versus non-drainage for single-level lumbar discectomy: a prospective randomized controlled study

BACKGROUND: Postoperative epidural haematoma and wound infection can cause devastating neurological damage in spinal surgery. Closed drainage is a common method to prevent epidural haematoma, infection and related neurological impairment after lumbar decompression; however, it is not clear whether drainage can reduce postoperative complications and improve clinical efficacy. This randomized study aims to explore the role of closed drainage in reducing postoperative complications and improving the clinical efficacy of single-level lumbar discectomy. METHODS: A total of 420 patients with single-level lumbar disc herniation were finally included in this study (169 females and 251 males, age 50.0 ± 6.4 years). A total of 214 patients were randomly assigned to the closed drainage group, and 206 patients were assigned to the non-drainage group. The incidence of postoperative fever, symptomatic epidural haematoma, wound infection and the need for revision surgery were compared between the two groups by the chi-square test or Fisher’s exact test. The visual analogue scale (VAS) and oswestry disability index (ODI) were used to evaluate the improvement of pain relief and the recovery of lumbar function. The VAS and ODI scores were compared between the two groups using t tests. RESULTS: The complications of the two groups were compared and analysed. There was only a statistically significant difference in the postoperative fever rate (p = 0.022), as the non-drainage group had a higher fever rate, but there were no significant differences in the rates of symptomatic epidural haematoma, wound infection or revision operation (p > 0.05). After concrete analysis, for the rate of fever less than 38.5 degrees, there was a statistically significant difference (p = 0.027), but there was no significant difference when the fever was greater than 38.5 degrees (p > 0.05). When comparing the VAS scores of the operation area on the first day after the operation, the pain relief in the closed drainage group was significantly better than that in the non-drainage group, with scores of 5.1 ± 0.8 and 6.0 ± 0.7, respectively (p < 0.001). However, there was no significant difference between the two groups in the other VAS scores of operation areas, the VAS scores of the lower extremity, or the ODI scores (p > 0.05). CONCLUSIONS: For single-level lumbar discectomy, closed drainage is beneficial for reducing postoperative low-grade fever and relieving pain in the operation area in the very early postoperative stage. However, drainage does not have a significant impact on reducing the incidence of postoperative complications or improving clinical efficacy. TRIAL REGISTRATION: Current Controlled Trials ChiCTR1800016005, May/06/2018, retrospectively registered.