Kim KA, McDonald M, Pik JH, Khoueir P, Wang MY.
Department of Neurological Surgery, Keck School of Medicine, University of Southern California, Los Angeles, California 90033, USA. keunyoun@usc.edu

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 degrees 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.

Taylor J, Pupin P, Delajoux S, Palmer S.
Clinique de L'Esperance, Nice, France.

OBJECT: The DIAM is a polyester-encased silicone interspinous dynamic stabilization device that can unload the anterior column and reestablish the functional integrity of the posterior column. METHODS: The DIAM was implanted in 104 patients between May 1, 2001 and October 30, 2001. A retrospective evaluation was performed based on chart review and patient questionnaire at a median follow-up interval of 18.1 months. There were no implant migrations, infections, or neurological injuries. Of the 20 patients who suffered adverse events, 13 underwent second lumbar spinal operations 0 to 19 months after the initial surgery (in seven the event occurred in a location other than the lumbar spine). The pain level as recorded by the physician showed improvement in 88.5%, no change in 9.6%, aggravation in 0%, and was indeterminate in 1.9%. The questionnaire revealed that at 18 months postoperatively, analgesic usage was decreased in 63.1%, increased in 12.3%, and unchanged in 24.6% of patients, and activities of daily living were improved in 46.2%, decreased in 30.8%, and unchanged in 23.1%. Specific outcomes measures for sitting, standing, physical activity, and psychosocial functioning revealed similar results.
CONCLUSIONS: The DIAM implant appears to be a useful and effective alternative in the surgical management of a wide range of lumbar disorders. Patient complications are few and satisfaction is high.