The mid-term clinical effect observation of Dynesys applied to the treatment of lumbar degenerative diseases with fatty infiltration of multifidus muscle / 中华骨科杂志

ABSTRACT

Objective:To investigate the clinical effect of Dynamic neutralization system applied to the treatment of lumbar degenerative diseases with fatty infiltration of multifidus muscle.Methods:From Jan 2015 to Dec 2017, a total of 53 patients of lumbar degenerative diseases with multifidus fatty infiltration treated by Dynesys in our hospital were analyzed, included 21 males and 32 females, aged 66.2±7.4 (range 48-81) years. There were lumbar spinal stenosis in 37 casesand lumbar disc herniationin 16 cases; the index level included L 2-S 1 in 3 cases, L 3-S 1 in 13 cases, L 2-L 5 in 5 cases, L 4-S 1 in 17 cases, and L 3-L 5 in 15 cases. The pedicle screws were inserted at the point of intersection of the outer edge of superior articular process and the midline of transverse process. After discectomy of herniated disc and hyperplastic ligamentum flavum, the distance between the upper and lower pedicle screws was measured and then the spacer of the corresponding length was cut out. Finally, the spacer was placed and fixed between the upper and lower pedicle screws by the elastic rope. The degree of multifidus fat infiltration, lumbar lordosis (LL), pelvic incidence (PI), pelvic tilt (PT), sacral slop (SS), range of motion (ROM), intervertebral height (IH), Japanese Orthopaedic Association (JOA) score, Oswestry disability index (ODI), the MOS 36-item short-form health survey (SF-36) and visual analog scale (VAS) were evaluated postoperatively. Results:The operation was performed successfully in all the patients. The operation duration was 173.5±64.7 (range 125-240) min. Intraoperative blood loss was 469.5±118.2 (range 380-620) ml. The patients were followed up for 47.9±6.7 (range 38-62) months averagely. At the last follow-up, the degree of fatty infiltration of the multifidus muscle showed no further progress by MR scan. There was no significant difference in ROM and IH at different time points preoperativelyand postoperatively. The LL recovered from 37.6°±8.8° to 43.2°±9.1°, the PT decreased from 24.7°±9.3° to 20.5°±5.1°, and the SS increased from 22.1°±7.7°to 26.3°±8.0°. The JOA score increased from preoperative 6.4±1.2 to 20.6±2.8, ODI decreased from preoperative 50.6%±11.3% to 13.0%±3.4%, SF-36 increased from preoperative 81.5±3.6 to 95.5±4.2, and the VAS decreased from preoperative 4.2±1.0 to 1.1±0.6. One patient experienced loosening and displacement on the left side pedicle screw of the L2 vertebral body 3.5 years after operation, and herclinical symptom improved significantly after conservative treatment.Conclusion:Dynesysis is safe and effective for the treatment of lumbar degenerative diseases with fatty infiltration of multifidus muscle, and it can restore the complete structure and function of tension band at lower back and prevent the progress of multifidus muscle fat infiltration combined with postoperative rehabilitation training.