• Journal of Korean Neurosurgical Society
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• v.46 no.4
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• pp.285-291
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• 2009

Objective : This study examined the change of range of motion (ROM) at the segments within the dynamic posterior stabilization, segments above and below the system, the clinical course and analyzed the factors influencing them. Methods : This study included a consecutive 27 patients who underwent one-level to three-level dynamic stabilization with Bioflex system at our institute. All of these patients with degenerative disc disease underwent decompressive laminectomy with/without discectomy and dynamic stabilization with Bioflex system at the laminectomy level without fusion. Visual analogue scale (VAS) scores for back and leg pain, whole lumbar lordosis (from L1 to S1), ROMs from preoperative, immediate postoperative, 1.5, 3, 6, 12 months at whole lumbar (from L1 to S1), each instrumented levels, and one segment above and below this instrumentation were evaluated. Results : VAS scores for leg and back pain decreased significantly throughout the whole study period. Whole lumbar lordosis remained within preoperative range, ROM of whole lumbar and instrumented levels showed a significant decrease. ROM of one level upper and lower to the instrumentation increased, but statistically invalid. There were also 5 cases of complications related with the fixation system. Conclusion : Bioflex posterior dynamic stabilization system supports operation-induced unstable, destroyed segments and assists in physiological motion and stabilization at the instrumented level, decrease back and leg pain, maintain preoperative lumbar lordotic angle and reduce ROM of whole lumbar and instrumented segments. Prevention of adjacent segment degeneration and complication rates are something to be reconsidered through longer follow up period.

• Journal of Korean Neurosurgical Society
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• v.46 no.5
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• pp.431-436
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• 2009

Objective : This study examines whether functional motion is present at one or more years after Bioflex System placement. BioFlex System is a flexible rod system which has been used to preserve motion at the area of implantation. There has not been a scientific study showing how much motion is preserved after implantation. Methods : A total of 12 consecutive patients underwent posterior dynamic stabilization using the BioFlex System. Six patients were treated using a L3-4-5 construct and other six patients using a L4-5-S1 construct. Follow-up ranged from 12 to 33 months and standing neutral lateral, extension, flexion and posteroanterior (PA) radiographs were obtained at 3, 6, 9, and 12 months and at more than 12 months postoperatively. Range of motion (ROM), whole lumbar lordosis, and ROMs of motion segments from L2 to S1 were determined. Results : Patients with a L3-4-5 construct demonstrated a decrease in mean ROM for whole lumbar decreased from 40.08 to 30.77. Mean ROM for L3-4 (6.12 to 2.20) and L4-5 (6.55 to 1.67) also decreased after one year. Patients with a L4-5-S1 construct demonstrated L4-5 (8.75 to 2.70) and L5-S1 (9.97 to 3.25) decrease of mean ROM at one year postoperatively. Lumbar lordosis was preservep at both L3-4-5 and L4-5-S1 constructs. Clinical results showed significant improvements in both study groups. Conclusion : The present study provides preliminary information regarding the BioFlex motion preservation system. We conclude that the BioFlex System preserves functional motion to some degree at instrumented levels. However, although total lumbar lordosis was preserved, ROMs at implantation segments were lower than preoperative values.