Bioabsorbable instrumentation for single-level cervical degenerative disc disease: a radiological and clinical outcome study

[Justin]

Journal of Neurosurgery: Spine. Nov 2009, Vol. 11, No. 5, Pages 529-537

Bioabsorbable instrumentation for single-level cervical degenerative disc disease: a radiological and clinical outcome study

Andre Tomasino, M.D., Harry Gebhard, M.D., Karishma Parikh, B.S., Christian Wess, M.D., and Roger Härtl, M.D.
Department of Neurological Surgery, Weill Cornell Medical College, New York–Presbyterian Hospital, New York, New York
Abbreviations used in this paper: ACDF = anterior cervical discectomy and fusion; ACP = anterior cervical plate; NDI = Neck Disability Index; VAS = visual analog scale; VB = vertebral body. ©1944-2009 by the American Association of Neurosurgeons

Object
The authors present the radiological and clinical outcome data obtained in patients who underwent single-level anterior cervical discectomy and fusion (ACDF) for cervical spondylosis and/or disc herniation; bioabsorbable plates were used for instrumentation. The use of metallic plates in ACDF has gained acceptance as a stabilizing part of the procedure to increase fusion rates, but when complications occur with these devices, the overall effectiveness of the procedure is compromised. As a possible solution, bioabsorbable implants for ACDF have been developed. This study investigates the feasibility and radiological and clinical outcomes of the bioabsorbable plates for ACDF.

Methods
The radiological and clinical outcomes of 30 patients were investigated retrospectively. All patients presented with cervical radiculopathy or myelopathy and underwent single-level ACDF in which a bioabsorbable anterior cervical plate and an allograft bone spacer were placed at a level between C-3 and C-7. Radiological outcome was assessed based on the fusion rate, subsidence, and Cobb angle of the surgical level. Clinical outcome was determined by using a visual analog scale, the Neck Disability Index, and the Odom criteria.

Results
There were no intraoperative complications, and no hardware failure was observed. No signs or symptoms of adverse tissue reaction caused by the implant were seen. Two reoperations were necessary due to postoperative blood collections. The overall complication rate was 16.7%. After 6 months, radiographic fusion was seen in 92.3% of patients. Subsidence at 11.3 ± 7.2 months was 3.1 ± 5.8 mm (an 8.2% change over the immediately postoperative results), and the change in the sagittal curvature was –2.7 ± 2.7°. The visual analog scale score for neck and arm pain and Neck Disability Index improved significantly after surgery (p < 0.001). Overall at 19.5 months postoperatively, 83% of the patients had favorable outcomes based on the Odom criteria.

Conclusions
Absorbable instrumentation provides better stability than the absence of a plate but graft subsidence and deformity rates may be higher than those associated with metal implants. There were no device-related complications, but adverse late effects cannot be excluded. The fusion rate and outcome are comparable to the results achieved with metallic plates. The authors were satisfied with the use of bioabsorbable plates as a reasonable alternative to metal, avoiding the need for lifelong metallic implants.

anterior cervical discectomy and fusion; bioabsorbable implant; spinal surgery; lordosis; kyphosis; subsidence.

[Katie]

This alternative was suggested to me several times when I spoke to the engineers at numerous companies who manufacture spinal prosthesis. It would be perfect for part of my problem, the metal allergies.

Unfortunately I still have to find something for the lumbar, but at least this is very encouraging.

Can you explain this part for me though? The reasons why this might happen? "Absorbable instrumentation provides better stability than the absence of a plate but graft subsidence and deformity rates may be higher than those associated with metal implants."