CLINICAL STUDIES PRELIMINARY EXPERIENCE USING A POLYETHERETHERKETONE (PEEK) CAGE IN THE TREATMENT OF CERVICAL DISC DISEASE Der-Yang Cho, M.D. Department of Neurosurgery, China Medical College Hospital, Taichung, Taiwan, Republic of China Wen-Rei Liau, M.D. Department of Neurosurgery, China Medical College Hospital, Taichung, Taiwan, Republic of China Wen-Yen Lee, M.D. Department of Neurosurgery, China Medical College Hospital, Taichung, Taiwan, Republic of China Jung-Tung Liu, M.D. Department of Neurosurgery, China Medical College Hospital, Taichung, Taiwan, Republic of China Chung-Lian Chiu, M.D. Department of Neurosurgery, China Medical College Hospital, Taichung, Taiwan, Republic of China Pon-Chun Sheu, M.D. Department of Neurosurgery, China Medical College Hospital, Taichung, Taiwan, Republic of China Reprint requests: Der-Yang Cho M.D., Department of Neurosurgery, China Medical College Hospital, No. 2 Yu-Der Road, Taichung, Taiwan, Republic of China. Email: d5057@hpd.cmch.org.tw Received, February 1, 2002. Accepted, July 22, 2002. OBJECTIVE: We investigated the effectiveness of a new material, polyetheretherketone (PEEK), in a spinal cage used in performing cervical spinal fusion for the correction of cervical kyphosis. METHODS: A total of 80 patients with various cervical diseases were divided into two groups. Patients in Group A (40 patients) underwent microdiscectomy and PEEK cage fusion, and patients in Group B (40 patients) were treated with microdisectomy and autogenous iliac crest graft (AICG) fusion. We evaluated the patients for cervical lordosis, the height of the foramina, the cross sectional area of the foramina, and fusion status on the basis of x-rays. The patients’ neurological and functional outcomes were assessed on the basis of the Prolo scale. Magnetic resonance imaging was also performed for spinal cord evaluation. RESULTS: The use of the PEEK cage in patients who undergo spinal fusion may increase cervical lordosis (mean, 2.33  3.00 mm; P = 0.03), whereas AICG fusion may not (mean, -0.84  6.69 mm; P = 0.49). The use of the PEEK cage was found to increase the height of the foramina (mean, 2.54  1.40 mm; P = 0.00) and increase its cross sectional area (mean, 40.36  23.53 mm 2 ; P = 0.00). The height of the foramina increased only in the PEEK group postoperatively. The cross sectional area of the foramina increased in both groups postoperatively. The complication rate in patients who underwent fusion proce- dures with the PEEK cage was less than that in patients who underwent fusion with AICG fusion (2.50 versus 17.50%; P = 0.03). Both groups had a satisfactory fusion rate (100 versus 93.1%). The patients’ postoperative Prolo scale scores were statistically better in the PEEK group (8.50  1.49 versus 7.17  2.13; P = 0.00), and more patients in the PEEK group than in the AICG group achieved excellent outcomes (66.63 versus 28.57%; P = 0.00). Because PEEK is radiotransparent on x-rays and few artifacts are seen on magnetic resonance imaging scans, it is better suited than autogenous iliac crest donor material for postoperative radiographic evaluation. CONCLUSION: The PEEK cage provides solid fusion, increased cervical lordosis, and in- creased height and cross sectional area of the foramina. There are few complications associated with the use of this cage, and the functional and neurological outcomes are satisfactory. It also facilitates postoperative x-ray and magnetic resonance imaging evaluation. The PEEK cage is therefore a good substitute for AICG fusion in patients with cervical disc disease. KEY WORDS: Autogenous iliac crest graft, Cage, Cervical disc disease, Interbody fusion, Microdisectomy, Polyetheretherketone Neurosurgery 51:1343-1350, 2002 DOI: 10.1227/01.NEU.0000035851.01555.22 www.neurosurgery-online.com T he use of spinal cages for spinal fusion in patients with cervical disc disease is popular not only because cages aid in increasing cervical foramina height (2) but also because they help correct cervical kyphosis (9, 19). Although some authors have supported performing a discectomy with- out grafting because it achieves good results in 85 to 92% of cases (18, 23), it is known that patients with postoperative kyphosis experience more frequent cervical pain in nongrafted cases (32). The cage has been shown to reduce the complica- tion rate by 22% in comparison with autogenous iliac crest NEUROSURGERY VOLUME 51 | NUMBER 6 | DECEMBER 2002 | 1343