Long-term outcome of posterior decompression and Dynesys stabilization for lumbar degenerative disease

English Keywords:Lumbar degenerative disease  Dynesys dynamic stabilization system  Long-term outcome

English Abstract:

  【Abstruact】 Objectives: To evaluate the long-term clinical and radiographic outcomes of posterior decompression and Dynesys stabilization in the treatment of lumbar degenerative disease. Methods: The clinical data of 163 patients underwent posterior decompression and Dynesys stabilization owing to lumbar degenerative disease were collected from July 2008 to Dec 2013 in our hospital. They were followed up for 78 to 144 months(95.4±15.6 months). There were 97 males and 66 females, aged from 31 to 60 years(43.5±11.7 years). There were 117 cases of single-segment fixation, 42 cases of double-segment fixation and 4 cases of three- segment fixation. The Oswestry disability index(ODI) and visual analogue scale(VAS) scores were compared before operation, 3 months after operation and at the final follow-up; the range of motion(ROM) of the operated segment and the upper adjacent segment were measured on the anteroposterior and lateral position and flexion and extension position X-ray films at preoperation, 3 months after operation and at the final follow-up. The occurrence of adjacent segment degeneration(ASD) and fixation related complications were evaluated. Results: The ODI and VAS scores at 3 months after operation and at the final follow-up were significantly improved compared with those before operation(P<0.05), the difference between the final follow-up and 3 months after operation was also statistically significant(P<0.05). The ROMs of the operated segments were 7.8°±2.1°, 4.6°±1.4° and 3.9°±1.5° at preoperation, 3 months after the operation and the final follow-up, respectively; the disc heights of the operated segments were 12.1±2.9mm, 12.8±3.5mm and 10.9±2.8mm, respectively; the ROM of upper adjacent segments were 8.3°±1.9°, 9.2°±2.7° and 10.2°±2.8°, respectively, the differences were all statistically significant between the values at 3 months after the operation and the preoperation value, the values at the final follow-up and the preoperation, as well as between the value at the final follow-up and the 3 months after the operation(P<0.05). Disc heights of upper adjacent segments were 12.7±3.1mm, 12.6±3.2mm and 12.1±2.8mm, respectively, with no statistical significance(P>0.05). At the final follow-up, 32 patients(19.6%) had ROM less than 4 degrees(clinical fusion group) and 131 patients(80.4%) had ROM more than 4 degrees(non-fusion group). The VAS score and ODI of the two groups were not statistically significant(P>0.05). At the final follow-up, 30 patients(18.4%) developed radiographic ASD, and 2 patients(1.2%) developed symptomatic ASD(one of whom had undergone revision surgery and the other conservative treatment). One patient developed deep infection at 2 months after operation and recovered after anti-infection treatment. Unilateral screw loosening occurred in 6 patients at the 5-year follow-up, and no surgical treatment was performed. Two patients with pedicle screw fracture did not undergo revision surgery due to lack of discomfort. There was no recurrence of surgical segmental protrusion in all patients. Conclusions: Dynesys dynamic system combined with posterior decompression in the treatment of degenerative lumbar spine diseases can achieve good long-term clinical outcome, and can preserve partial ROM of the operated segment.