Radiologic Assessment of Subsidence in Stand-Alone Cervical Polyetheretherketone (PEEK) Cage. |
Sung Kon Ha, Jung Yul Park, Se Hoon Kim, Dong Jun Lim, Sang Dae Kim, Sang Kook Lee |
Department of Neurosurgery, Korea University Medical Center Ansan Hospital, Ansan, Korea. jypark@kumc.or.kr |
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ABSTRACT |
OBJECTIVE Aim of study was to find a proper method for assessing subsidence using a radiologic measurement following anterior cervical discectomy and fusion (ACDF) with stand-alone polyetheretherketone (PEEK), Solis(TM) cage. METHODS: Forty-two patients who underwent ACDF with Solis(TM) cage were selected. With a minimum follow-up of 6 months, the retrospective investigation was conducted for 37 levels in 32 patients. Mean follow-up period was 18.9 months. Total intervertebral height (TIH) of two fused vertebral bodies was measured on digital radiographs with built-in software. Degree of subsidence (DeltaTIH) was reflected by the difference between the immediate postoperative and follow-up TIH. Change of postoperative disc space height (CT-MR DeltaTIH) was reflected by the difference between TIH of the preoperative mid-sagittal 2D CT and that of the preoperative mid-sagittal T1-weighted MRI. RESULTS: Compared to preoperative findings, postoperative disc height was increased in all cases and subsidence was observed only in 3 cases. For comparison of subsidence and non-subsidence group, TIH and CT-MRDeltaTIH of each group were analyzed. There was no statistically significant difference in TIH and CT-MR DeltaTIH between each group at 4 and 8 weeks, but a difference was observed at the last follow-up TIH (p=0.0497). CONCLUSION: ACDF with Solistrade mark cage was associated with relatively good radiologic long-term results. Fusion was achieved in 94.5% and subsidence occurred in 8.1% by the radiologic assessment. Statistical analysis reveals that the subsidence seen later than 8 weeks after surgery and the development of subsidence does not correlate statistically with the change of the postoperative disc space height. |
Key Words:
Cervical PEEK cage; Radiologic assessment; subsidence; Fusion rate; Anterior cervical discectomy and fusion |
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