ANTERIOR INTERBODY FUSION WITH THE BAK-CAGE IN CERVICAL SPONDYLOSIS

BAK-C is a new autostabilizing interbody cage which is implanted durin g an anterior cervical procedure to provide stability to the motion se gment and allow fusion to occur. Special intrumentation is provided wi th a bone collecting reamer. The system utilizes surgical site bone gr aft as the osteo-inductive material within the implant. Biomechanical testing indicates improved stability and animal studies show good fusi on. The basic principle is distraction-compression using the tension f orces of the annulus fibrosus. Operative material concerns a two years experience with 80 patients (101 levels), 72 with cervical radiculopa thy, 8 with myelopathy. Clinical evaluation is assessed on a ten point analogue pain scale for neck and arm/shoulder pain, with neurological examination. Radiological evaluation includes dynamic X-rays, myelo-C T and MRI. Patients are re-evaluated at 1, 6, 12 months postoperativel y. Results for neck and radicular pain is excellent, but neurological recovery for radiculopathy and myelopathy is quite different. Radiolog ical results are also good With (except one case) no instability, no c age migration, no kyphosis, no pseudarthrosis. Bone fusion is assessed at 6 and 12 months. Complications are few with proper technique, main ly correct distraction, symmetrical endplate drilling and lateral X-ra y control. Only one patient needed an early re-operation with addition al miniplate fixation. Immediate stability with good clinical response and no graft morbidity are the advantages of this implant compared to conventional cervical interbody grafting techniques.