orexin receptor br Materials and methods br Results

Materials and methods
Results
Discussion Dynesys stabilization with interbody fusion is an alternative treatment for multisegmental lumbar disc degeneration with spondylolisthesis. Segment-by-segment surgical treatments with and without fusion have been developed for multisegmental lumbar disease. Fusion surgery is usually performed in highly unstable segments or in discs with advanced intervertebral degeneration. In this study, nonfusion Dynesys surgery was performed in cases of mild disc degeneration and in cases of unstable motion segments in degenerated intervertebral discs. The Dynesys hybrid stabilization was originally developed by Schwarzenbach et al to treat multisegmental degenerative disc disease by combining fusion and nonfusion techniques. This study analyzed 80 lumbar segments treated in 31 patients over a mean follow-up orexin receptor of 39 months (range: 24–90 months). Evaluations of functional outcomes by ODI and VAS showed significant improvements. Solid fusion was achieved in 100% of the segments. Out of 31 patients, three (9.7%) patients, including two with ASD, required further surgical intervention. The surgical results suggest that segment-by-segment treatment by Dynesys combined with interbody fusion is technically feasible, safe, and effective for surgical treatment of multisegmental degenerative disc disease. The patient follow-up also showed good clinical outcomes after hybrid surgery. Although good clinical outcomes of the hybrid technique for treating multisegmental degenerative disc disease have been reported previously, no studies have reported the kinematic behavior of hybrid constructs. Kumar et al evaluated radiographic change in the intervertebral disc after dynamic stabilization by Dynesys. Of the 32 patients in their study, 12 underwent Dynesys stabilization with fusion, and none showed significant change in the adjacent discs. Use of dynamic stabilization with interbody fusion (hybrid construct) after microsurgery decompression in multisegmental lumbar disease has several potential benefits: first, the hybrid constructs enable stabilization of the fused segment by the tension band effect. The tension band effect on the spacer and cord is known to decrease motion in the fused segment and to improve the fusion rate. As in Schwarzenbach et al, the current study obtained a 100% fusion rate in the fused segment. Furthermore, dynamic neutralization decreased the load on the facet joint and protected the facet joint in the bridged segment. A comparison of motion in the bridged segment before and after surgery showed no significant difference. Motion in the nonfusion segment (bridged segment) was preserved to provide a transition zone between the fused segment and motion segment and to protect the adjacent segment. Theoretically, the transition zone should reduce degeneration of the adjacent segment. However, analyses of the adjacent segment in our patients showed hypermobility. Previous in vitro experiments showed that the kinematic effects obtained by Dynesys were similar to those observed in fusion surgery. A possible explanation is that Dynesys provided intersegmental stability by functioning similar to a rigid-rod-fixation system and caused hypermobility of the adjacent motion segments. The rigidity of Dynesys is known to reduce its protective effect on the adjacent segment. Our results also revealed decreased ROM in the global segment and increased ROM in the adjacent segments. The kinematic changes in the hybrid construct are apparently similar to those that occur in a Dynesys stabilization procedure. One concern about the Dynesys hybrid construct applied here is its high rigidity. Although the effects of spacer length and cord tension on segmental flexibility and rigidity are still debated in the literature, we favor that determining these essential parameters before performing Dynesys improves outcomes of the procedure. Niosi et al reported that spacer length affects compression of posterior elements, that is, the facet load increases as spacer length decreases. Niosi et al also showed that a longer spacer length increases ROM and the overall size of the motion pattern. Although evidence of the precise effects of spacer length and cord tension is not yet convincing, a longer spacer and a lower tension cord may increase the flexibility of Dynesys. Based on our clinical experience, the difference in spacer length and cord tension between the fused segment and bridged segment should be set to obtain optimal flexibility of the bridged segment. This study used a long spacer length and a low cord tension in the bridged segment. By contrast, a short spacer length and a high cord tension were used in the fused segment to create a rigid segment, which improved the fusion rate.