[Clinical research of dynamic cervical implant and cage fusion in two-level cervical disc protrusion]

Abstract

Objective: To discuss the safety and effectiveness of combined dynamic cervical implant (DCI) and Cage fusion in the treatment of two-level cervical disc protrusion.

Methods: Between September 2009 and June 2011, 16 cases of two-level cervical disc protrusion were treated with combined DCI and Cage fusion. Of 16 cases, 10 were male and 6 were female, with a mean age of 44.1 years (range, 37-64 years) and with a mean disease duration of 5.1 years (range, 2-8 years), including 8 cases of cervical myelopathy, 5 cases of nerve root cervical myelopathy, and 3 cases of mixed cervical myelopathy. Radiological results indicated degenerative intervertebral discs and compressed never root or spinal cord. Involved discs included C3,4 and C4,5s (1 case), C3,4 and C5,6 (5 cases), C4,5 and C5,6 (3 cases), C4,5 and C6,7 (5 cases), and C5,6 and C6,7 (2 cases). The neck disability index (NDI), Japanese Orthopedic Association (JOA) score, and visual analogue scale (VAS) were used to evaluate the neurological function and pain relief. The stabilities and activities of involved segments, intervertebral fusion, and displacement of Cages were observed during follow-up.

Results: Primary healing of incisions was obtained in all cases; no complication of hematoma, infection, cerebrospinal fluid leakage, or neural function damage occurred. All 16 patients were followed up 18 months on average (range, 6-36 months). The cervical X-ray results indicated that the activities of involved segments was (7.8 +/- 3.1) degrees, showing no significant difference (t = 0.655, P = 0.132) when compared with preoperative value [(7.3 +/- 2.6) degrees]. No implant loosening was observed; slight heterotopic ossification occurred in 1 patient at the posterior rim ofintervertebral space. No cage loosening or sinking was seen, and good fusion was achieved. The mean time of fusion was 4.5 months (range, 3-8 months). NDI, JOA, and VAS scores at last follow-up (18.3 +/- 5.1, 15.7 +/- 1.5, and 3.4 +/- 1.8 respectively) were significantly improved (t = 2.131, P = 0.016; t = 3.126, P = 0.024; t = 6.102, P = 0.038) when compared with preoperative scores (49.6 +/- 11.3, 12.8 +/- 2.0, and 6.7 +/- 1.2 respectively).

Conclusion: A combination of DCI and intervertebral Cage fusion has satisfactory early effectiveness in treatment of two-level cervical intervertebral protrusion for maintaining the stability and activity of cervical vertebrae.