Expansive laminoplasty for cervical myelopathy with interconnected porous calcium hydroxyapatite ceramic spacers: comparison with autogenous bone spacers.
METHODS
Expansive cervical laminoplasties with interconnected porous calcium hydroxyapatite ceramic (IP-CHA) spacers were performed in cervical myelopathy patients.


OBJECTIVE
To evaluate the usefulness and osteoconductive capability of IP-CHA spacers in expansive laminoplasty.


BACKGROUND
Expansive laminoplasty for cervical myelopathy is designed to preserve the posterior structures, so as to prevent postoperative development of instability and cervical kyphosis. The technique requires successful reconstruction of the laminae of vertebral arches, as sinking or nonunion of the expanded laminae may induce neurologic regression, segmental motor paralysis, and postoperative axial pain. A novel IP-CHA with sufficient biocompatibility and mechanical strength was developed as an artificial bone substitute.


METHODS
Expansive open-door laminoplasties were performed in 88 cervical myelopathy patients, and both autogenous bone spacers harvested from the spinous processes and IP-CHA spacers in combination with bone marrow were alternately grafted into the opened side of each lamina. All patients were followed up with computerized tomography scans, and bonding rates for both the IP-CHA and autogenous spacers, bone fusion rates of the hinges of the laminae, and complications associated with the implants were examined.


RESULTS
Clinical symptoms significantly improved in all patients without major complications related to the procedure. The IP-CHA spacers demonstrated comparable bone bonding to the autogenous spacers on postoperative computerized tomography scans. The expanded laminae withstood expanded positions without sinking or floating throughout the followups, and the hinges completely fused in more than 95% of patients in both groups within 1 year.


CONCLUSIONS
The IP-CHA spacer contributed to high bone fusion rates of the spacers and hinges of the laminae, and there were no complications associated with their use. Cervical laminoplasty with the IP-CHA spacers is a safe and simple method that yields sufficient fixation strength and provides sufficient bone bonding within a short period of time after operation.
Tanaka
Nobuhiro
N
Department of Orthopaedic Surgery, Graduate School of Biomedical Sciences, Hiroshima University, Hiroshima, Japan. nobut@hiroshima-u.ac.jp
Nakanishi
Kazuyoshi
K
Fujimoto
Yoshinori
Y
Sasaki
Hirofumi
H
Kamei
Naosuke
N
Hamasaki
Takahiko
T
Yamada
Kiyotaka
K
Yamamoto
Risako
R
Nakamae
Toshio
T
Ochi
Mitsuo
M
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D018786:Bone Substitutes; D002516:Ceramics; D002574:Cervical Vertebrae / Q000601:surgery; D017886:Durapatite; D005260:Female; D006801:Humans; D007796:Laminectomy / Q000295:instrumentation* / Q000379:methods; D008297:Male; D008875:Middle Aged; D016062:Porosity; D019736:Prostheses and Implants; D011474:Prosthesis Design; D013118:Spinal Cord Diseases / Q000175:diagnosis / Q000601:surgery*; D016896:Treatment Outcome
D018786:Bone Substitutes; D017886:Durapatite