Article
Hardware failure in cervical fusion in degenerative disc disease
Materialversagen bei zervikaler Fusion bei degenerativen Bandscheibenerkrankungen
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Published: | May 4, 2005 |
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Outline
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Objective
Cervical discectomy and fusion is a widely accepted procedure in treating degenerative cervical disc disease causing radicular and myelopathic symptoms. Despite good results in respect to patients satisfaction several problems occur with cervical fusion hardware. The objective of this study was to analyse hardware failure of cervical fusion with respect to clinical outcome.
Methods
Pre- and postoperative lateral radiographs, operative and clinical data of patients who underwent cervical fusion during a four year period have been analysed for complications, and the need of repeated surgery.
Results
203 patients had been treated with cervical fusion surgery for radicular and myelopathic symptoms. The fusion was achieved by cages in 152, by plate-cages in 11, and by autologous bone grafts in 40 patients. 23 of these 40 patients underwent additional anterior plating (Caspar plate). An overall of 7 patients had a second surgery (3.5%). 2.5% of the patients (4/163) fused with cage (cages and plate-cages) had a second operation because the cages dislocated ventrally. Dorsal dislocation however could not be observed. 11.8% of the patients fused with tricortical autologous bone graft without additional plating were operated a second time because the graft extruded (2/17), and 2.9% of the patients fused with an additional plating (plate-cage or Caspar plate, respective) had a second surgery because a screw dislocated (1/34). Cage subsidence was analysed in a subgroup of patients. Nearly half of the patients had a subsidence equal or more than 40% of the disc space height achieved immediately after surgery. The lordosis angle of the disc operated on diminished slightly during follow-up. However, there was no correlation between subsidence and loss of lordosis and patients satisfaction one year after operation.
Conclusions
Cervical fusion with cages, autologous bone grafts, and with or without additional ventral plate is a save procedure to reduce radicular and myelopathic symptoms. However there is a significant number of hardware problems some of them with the need of repeated surgery. The number of cages subsided into adjacent vertebral bodies is surprisingly high. This subsidence may interfere with the degree of decompression of nerve roots. However no correlation was found with respect to cage subsidence and patients satisfaction.