Change of Lumbar Motion after Multi-Level Posterior Dynamic Stabilization with Bioflex System : 1 Year Follow Up

Abstract

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.

Posterior Decompression and Fusion: Whole-Spine Functional and Clinical Outcomes

“…These two factors can explain the reduced preoperative LL (-20.90 ο ±1.92 ο ) which was further reduced at 3 months (-17.05 ο ±1.88 ο ) and remained almost stable at 6 months (-18.95 ο ±2.26 ο ). The course of the initial reduction and then the increase in the lordosis is also reported by other researchers who examined the posterior lumbar fusion [ 33 ]. However, the fact that the LL was just -21.40 ο ±1.98 ο even at 12 months postoperatively, is the result of the use of a stabilization system with rods in the applied-technique [ 4 , 33 ].…”

“…The course of the initial reduction and then the increase in the lordosis is also reported by other researchers who examined the posterior lumbar fusion [ 33 ]. However, the fact that the LL was just -21.40 ο ±1.98 ο even at 12 months postoperatively, is the result of the use of a stabilization system with rods in the applied-technique [ 4 , 33 ]. Characteristically, Boos and Webb (1997) [ 4 ] reported that the use of rods reduces the LL especially if the fusion includes healthy motion segments.…”

Dynamic radiographic results of different semi-rigid lumbar fusion devices for degenerative lumbar spondylolisthesis: “dynamic rod” vs. “dynamic screw head”

“…Cakir et al reported adjacent level disc pressure and adjacent level facet joint pressure as other factors contributing to the risk of ASD after fusion of the lumbar spine (2). Park et al suggested putative risk factors associated with ASD in lumbar or lumbosacral fusion groups, such as facet violation, fusion length, pre-existing degenerated disc at the adjacent level, lumbar stenosis, age, osteoporosis, and post-menopausal state (15). We suggest that risk factors of additional stress on adjacent segments after fusion surgery were related to possible multiple conditions, and not only to fusion device difference as stated in previous reports.…”

“…Among these complications, acceleration of ASD is common and can lead to significant stenotic lesion, instability, and disc rupture, requiring an additional surgical modality. It has been proposed that lumbar fusion surgery may induce hyper-mobility with increasing intradiscal pressure at adjacent segments and alterations in axial loading distribution (15).…”

Adjacent Segment Degeneration After Lumbar Dynamic Stabilization Using Pedicle Screws and a Nitinol Spring Rod System With 2-year Minimum Follow-up

“…4,15 Some reports have demonstrated good clinical outcomes and a preventive effect on adjacent level degeneration of the BioFlex dynamic stabilization system. 4,15 Some reports have demonstrated good clinical outcomes and a preventive effect on adjacent level degeneration of the BioFlex dynamic stabilization system.…”