RESUMO
OBJECTIVE: Postoperative fibrosis is one of the most important causes of failed back surgery syndrome after lumbar disc surgery. Numerous natural and synthetic materials have been investigated as means to prevent or reduce postoperative scarring after these operations. Preservation of the ligamentum flavum for this purpose has not been studied in depth. A prospective, randomized, controlled clinical study was conducted. The aim was to present a new technique for preserving the ligamentum flavum during lumbar discectomy, and to evaluate whether this helps prevent or diminish postoperative fibrosis. METHODS: Twenty patients with unilateral L5-S1 disc herniation were randomly divided into two equal groups. Group A patients underwent classic microlumbar discectomy, and Group B patients underwent the same procedure but with preservation of the ligamentum flavum. Visual analog pain scale (VAPS) scores, Oswestry scale scores, and straight-leg raising angles were recorded preoperatively and at 6 months postoperatively. Differences between the pre-operative and postoperative findings for each group were statistically compared using the Wilcoxon test. Magnetic resonance imaging was also done at 6 months to assess the extent of postoperative fibrosis, and a "scarring grade" was recorded for each patient. The group findings for this were analyzed with Levene's test. RESULTS: Both groups' clinical parameters were significantly improved at 6 months postsurgery. In Group A, the mean pre- and postoperative VAPS scores were 9.2 and 3.2, respectively (P < 0.05); the corresponding mean Oswestry scale scores were 88 and 28.2, respectively (P < 0.05); and the corresponding mean straight-leg raising angles were 290 and 630, respectively (P < 0.05). In Group B, the mean pre- and postoperative VAPS scores were 9.2 and 2.6, respectively (P < 0.05); the corresponding mean Oswestry scores were 85.2 and 22.2, respectively (P < 0.05); and the corresponding mean straight-leg raising scores were 260 and 710, respectively (P < 0.05). The mean scarring grades in Groups A and B were 1.8 and 1.0, respectively (P < 0.05). CONCLUSION: The groups both showed satisfactory clinical outcomes and the improvements were comparable; however, the group with preserved ligamentum flavum showed significantly less local fibrosis at 6 months postoperatively. The authors speculate that this surgical technique provides a physical protective barrier that can reduce or even eliminate fibrosis-related complications after lumbar disc surgery.
