Analysis of mid- and long-term outcomes of discectomy and Dynesys dynamic stabilization system fixation in the treatment of single level lumbar disc herniation in young adults

English Keywords:Lumbar disc herniation  Dynesys dynamic stabilization system  Young adults  Discectomy

English Abstract:

  【Abstract】 Objectives: To observe the mid- and long-term outcomes of discectomy and Dynesys dynamic stabilization system fixation in the treatment of single level lumbar disc herniation(LDH) in young adults. Methods: A retrospective analysis was performed on 62 young adult patients with single level LDH who underwent orthopedic surgery in the Department of Orthopaedics in our hospital between December 2010 and August 2014 and with complete data. Among the patients, 31 cases were treated with discectomy and Dynesys dynamic stabilization system fixation(Dynesys group), and the rest 31 were treated with discectomy alone(control group). There were no significant differences in baseline data between the two groups such as age, gender ratio, body mass index(BMI), duration of disease, comorbidities, smoking history, and surgical segments. Surgical-related data and complications were collected for both groups of patients. The visual analogue scale(VAS), Oswestry disability index(ODI), and disc height(DH), range of motion(ROM) and modified Pfirrmann grade of the surgical and proximal adjacent segment were compared between the two groups before surgery and at the final follow-up. Results: The control group had shorter operative time and postoperative hospital stay, and less intraoperative blood loss(P<0.05). Three cases in the Dynesys group and 1 case in the control group were found to have dural tears during operation, which were all carefully sutured and repaired, and no cerebrospinal fluid leakage occurred after surgery; One patient in each group had fever during hospitalization, who were both treated with antibiotics and ruled out of surgical site infection. One patient in the control group was re-admitted for debridement due to incision exudation and poor healing one month after surgery. The follow-up time was 72-109 months(91.8±11.1 months) in the Dynesys group and 72-116 months(93.7±12.7 months) in the control group. The VAS scores of low back pain and leg pain and ODI in both groups were significantly improved at the final follow-up compared with those before surgery(P<0.05), and there was no significant difference between the two groups at the same time point(P>0.05). At final follow-up, the DH of the surgical segments in both groups was significantly lower than that before surgery(P<0.05), and the loss in the control group was more significant than that in the Dynesys group(P<0.05); There was no significant change in DH in the proximal adjacent segments in both groups compared with that before surgery. In the Dynesys group, the ROM of the surgical segment was partially preserved(2.7°±2.1°) at the final follow-up, but it was significantly lower than that before surgery(P<0.05); The ROM of the proximal adjacent segments was significantly increased compared with that before surgery(P<0.05), but there was no significant difference compared with the control group. At the final follow-up, the modified Pfirrmann grades of the surgical segments and proximal adjacent segments in both groups had progressed compared with those before surgery(P<0.05). The progression of degeneration of the surgical segments in the control group was more significant than that in the Dynesys group(P<0.05). During the follow-up period, in the Dynesys group, there was no recurrence of disc herniation in all the patients at the surgical segment, nor breakage or loosening of internal fixation or reoperation; Five cases with preoperative segmental instability were all treated with Dynesys dynamic stabilization system fixation, and no segmental instability occurred postoperatively. In the control group, three patients underwent interbody fusion after ineffective conservative treatment due to recurrence of disc herniation, and one patient received interbody fusion due to postoperative low back pain and instability of the surgical segment. There was no symptomatic adjacent segmental degeneration in both groups and no significant difference in the overall complication rate between the two groups(P>0.05). Conclusions: Discectomy combined with Dynesys dynamic fixation is safe and effective for the treatment of single level LDH in young adults, which can reduce LDH recurrence and retain a certain range of motion of the surgical segment.