A PROSPECTIVE CASE CONTROL ANALYSIS COMPARING CERVICAL THREADED FUSION CAGES TO NON-INSTRUMENTED BONE ONLY ANTERIOR CERVICAL DECOMPRESSION AND FUSION (ACDF) FOR A SINGLE LEVEL CERVICAL DISC DISEASE FROM C3 TO C7.

Abstract

Background: Smaller versions of threaded lumbar cages were developed for cervical spine to obviate the need for allograft, iliac autograft use and to provide initial stability before fusion. Clinical trials of threaded cervical fusion cages have shown higher fusion rates and lower rates of graft-donor site complications.

Study design/Aims: Prospective. Radiological and clinical outcomes of an age, sex and diagnosis matched patient population who underwent cervical fusion with (A) BAK/C cages filled with autograft reamings (Center-pulse Spine-tech Inc., Minneapolis, MN) (N=50) were compared with (B) Anterior cervical decompression and fusion (ACDF, N=50).

Methods: Patients with symptomatic cervical discogenic radiculopathy were treated with either anterior cervical discectomy with uninstrumented bone-only fusion (ACDF) or BAK/C fusion cage(s). Independent radiographic assessment of fusion was made and patient-based outcome was assessed by a Short Form (SF)-36 Health Status Questionnaire. All patients had minimum follow up of at least 2 years.

Results: Similar outcomes were noted for duration of surgery, hospital stay, improvements in neck pain and radicular pain in the affected limb, improvements in the SF-36 Physical Component subscale and Mental Component subscale, and the patients’ perception of overall surgical outcome. Symptom improvements were maintained at 2 years. Iliac crest harvesting was carried out as a standard procedure in all cases of ACDF whereas only 2 cases in BAK/C group required the same. Average operative time of 115 minutes and 145 minutes, blood loss of 110ml and 175ml and hospital stay of 1.5 and 3.5 days were noted for BAK/C and ACDF groups respectively. Successful fusion was achieved in 49 cases in BAK/C and 46 patients in ACDF group. None of the patients in the BAK/C group had reappearance of symptoms while 3 patients in ACDF group had developed symptomatic adjacent level disc disease. The complication rate for the ACDF group was 9% compared with an overall complication rate of 3% with BAK/C. Complications that necessitated a second operative procedure included

1. Graft dislodgement (N=3) and

2. Cage subsidence, both requiring re-operation in the form of ACDF with plate supplementation.

Conclusions: These results demonstrate that outcomes after a cervical fusion procedure with a threaded cage are the same as those of a conventional uninstrumented bone-only anterior discectomy and fusion with a low risk of complications, less operative time and rare need for autogenous bone graft harvest.