[Device implanted complications of Coflex interspinous dynamic stabilization].

OBJECTIVE: To investigate device implanted complications and corresponding therapeutic strategies of Coflex interspinous dynamic stabilization system for lumbar spine intraoperatively and postoperatively.

METHODS: From September 2008 to August 2010, 133 cases of degenerative disease of lumbar spine including 62 males and 71 females, ranging from 35 to 81 years of age (mean 60.8 years), underwent or planed to be underwent decompression with Coflex interspinous dynamic stabilization system were reviewed retrospectively, and 13 cases including 6 males and 7 females, ranging from 41 to 71 years of age (mean 58.6 years), occurred device implanted complications. The Coflex implanted complications were analyzed, and therapeutic strategies according to different character were carried out, scores of visual analogue scale (VAS), Oswestry disability index(ODI) and effect-related data preoperatively, postoperatively, after conservative treatment and in final follow-up were evaluated with paired-samples t test.

RESULTS: Thirteen cases of Coflex implanted complications and treatment applied included: 3 cases occurred fracture of spinous processes intraoperatively were treated by pedicle screws instead; 2 cases occurred fracture of spinous processes postoperatively or during follow-up, including 1 case underwent revision with pedicle screws, another 1 case treated with conservative treatment; 4 cases with degenerative coronal spondylolysis in surgical segments, 1 case with sagittal instability preoperatively, and 1 case with device dislodgment in follow-up all suffered aggravated pain and received conservative treatment; 1 case suffered implanted malposition intraoperatively was underwent internal fixation with pedicle screws instead; at length, 1 case with aggravated pain postoperatively and without definite reason received revision with internal fixation of pedicle screws demolishing the Coflex. The follow-up time of 13 cases ranged from 20 to 38 months (mean 27.6 months); and 7 cases implanted Coflex with aggravated pain of lumbar and lower limb, but the position of device can still maintained, were received conservative treatment, and whose score of VAS and ODI in the final follow-up were 1.9 ± 0.7 and 23.2 ± 3.4, and comparing to 6.1 ± 1.1 and 58.1 ± 3.0 preoperatively, evident improvement was got finally (t = 8.2 and 18.2, P < 0.01). Scores of VAS and ODI of 2 cases with Coflex implanted complications underwent revision with pedicle screws were also improved correspondingly.

CONCLUSIONS: Coflex interspinous dynamic stabilization system implanted should be avoided to cases who suffered with osteoporosis, too narrow interspinous space and intervertebral coronal spondylolysis or sagittal instability; and choice of device, depth of implantation and intensity of clumping should be appropriate. For patients with symptom but device still in right position, conservative treatment can be carried out; but for patients subjected to malposition of device, failure of implantation intraoperatively or intolerance to device, revisions and salvages should be underwent with internal fixation of pedicle screws.