The superiority of PEEK cages over titanium cages for bony fusion was not demonstrated. Additionally, we found unfavorable radiographic findings in the cases with a PEEK cage, which may lead to nonunion. Improvement in biocompatibility of a PEEK cage will be needed to increase the fusion rate.

A total of 64 patients with cervical spondylotic myelopathy (CSM) were assessed in this study. Forty-two patients underwent selective expansive open-door laminoplasty (ELAP). Twenty-two patients who underwent conventional C3-7 ELAP served as controls. There were no significant differences in recovery rate of JOA scores, C2-C7 angle or cervical range of motion between two groups. Incidence of axial symptoms and segmental motor paralysis in selective ELAP was significantly lower than those in the C3-7 ELAP. Size of anterior compression mass, postoperative spinal cord positions and decompression conditions were evaluated using preoperative or postoperative MRI in 50 of 64 patients. There was a positive correlation between number of expanded laminae and maximum anterior spaces of spinal cord. Incomplete decompression was developed in three of 37 patients in selective ELAP and in two of 13 patients in C3-7ELAP. Mean size of anterior compression mass at incomplete decompression levels was significantly greater than that at complete decompression levels. Since, there was less posterior movement of the spinal cord in selective ELAP than that in C3-7ELAP, minute concerns about size of anterior compression mass is necessary to decide the number of expanded laminae. Overall, selective ELAP was less invasive and useful in reducing axial symptoms and segmental motor paralysis. This new surgical strategy was effective in improving the surgical outcomes of CSM, and short-term results were satisfactory.

Our results suggest that in IVD maintenance against the present type of mechanical stress, modulation of PG plays an important role and may be associated with molecular changes in PG-related genes.

Posterior lumbar interbody fusion (PLIF) is a standard surgical technique for the lumbar degenerative diseases. However, some problems such as collapse or retropulsion of the grafted bone and pseudoarthrosis have been reported when autogenous or cadaveric bone is used. Two iliac bone blocks with one-side cortex and one dense hydroxyapatite (HA) block were grafted together into the interbody space as in a sandwich. Cancellous bone chips locally harvested were also grafted onto the anterior and lateral aspect of the HA block. Twenty-six patients (12 males, 14 females) who could be followed minimally for 2 years were examined. The surgical outcome of each patient was evaluated by the Japanese Orthopaedic Association Assessment of Treatment of Low Back Pain (JOA score) and the recovery rate. Radiographic evaluation was based on the extent of bony union, the presence of a clear zone in the upper or lower margin of the HA block, cracking of the HA block, sinking of the HA block, and changes in lumbar-sagittal alignment pre- and postoperatively. The overall recovery rate ranged from 42.9% to 100% (mean 88.3%). Bony union was confirmed in 25 patients (96.2%). Clear zone was observed in 9 of 68 contact surfaces (13.2%). Sinking was observed in 8 of 34 segments (23.5%), and cracking of HA block was observed in 6 segments (17.6%). A mean loss of lordosis was found to be 2.4 degrees . The dense HA block is a useful substitute for autogenous bone graft for PLIF.

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