✓Numerous new posterior dynamic stabilization (PDS) devices have been developed for the treatment of disorders of the lumbar spine. In this report the authors provide a classification scheme for these devices and describe several clinical situations in which the instrumentation may be expected to play a role. By using this classification, the PDSs that are now available and those developed in the future can be uniformly categorized.

Object To assess the safety and efficacy of the DIAM implant, the authors compared the mean 12-month outcomes in patients who underwent lumbar surgery with DIAM placement and in those who underwent lumbar surgery only. Methods Of 62 patients who underwent simple lumbar surgery (laminectomy and/or microdiscectomy) in a 24-month period, 31 underwent concomitant surgical placement of a DIAM interspinous process spacer (33 devices total). Radiographic imaging, pain scores, and clinical assessments were obtained postoperatively to a mean of 12 months (range 8–25 months). Patients who did not undergo implantation of an interspinous process spacer (Group C) were compared with and stratified against patients who underwent placement of a DIAM implant (Group D). In Group D, no statistically significant differences were noted in anterior or posterior disc height when comparing patients pre- and postoperatively. Compared with Group C, a relative kyphosis of less than 2° was noted on postoperative images obtained in Group D. No statistically significant differences in visual analog scale (VAS) pain scores or MacNab outcomes were noted between Groups C and D at a mean of 12 months of follow up. Complications in Group D included three intraoperative spinous process fractures and one infection. Conclusions After simple lumbar surgery, the placement of a DIAM interspinous process spacer did not alter disc height or sagittal alignment at the mean 12-month follow-up interval. No adverse local or systemic reaction to the DIAM was noted. No difference in VAS or MacNab outcome scores was noted between the groups treated with or without the DIAM implants, particularly when the DIAM was used to alleviate low-back pain.

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✓ Ankylosing spondylitis can lead to severe cervical kyphosis, causing problems with forward vision, swallowing, hygiene, patient functionality, and social outlook. Evaluation of patients with cervical flexion deformity includes assessment of global sagittal balance and chin–brow angle. The primary treatment in extreme disabling cases is surgical correction involving a posterior cervical extension osteotomy, which is a technically demanding procedure with considerable risk of neurological injury. To address the potential complications with extension osteotomy, the authors of several reports have described modifications to the surgical technique. These developments incorporate recent advances in anesthesia, neuromonitoring, and spinal instrumentation. Complications associated with the procedure include subluxation at the osteotomy level, spinal cord injury, radiculopathy, dysphagia, and pseudarthrosis. Although the risks of spinal correction are considerable, extension osteotomy remains an effective treatment modality for patients with disabling cervical flexion deformity.