En bloc laminoplasty performed with threadwire saw.
OBJECTIVE
To introduce a method for a simple, nonexpansive laminoplasty that can be performed with a threadwire saw (T-saw) after en bloc laminotomy has been performed. The method can be applied along the entire spinal region, including the thoracic and lumbar spine.


METHODS
An en bloc laminotomy of trapezoid shape at the cross section is performed bilaterally at the junctional area of the lamina and facet joint with a thin, flexible T-saw, while preserving the supraspinous, interspinous, and interlaminar ligaments. After the intradural procedure has been performed, the laminar flap is replaced in its original site and fixed with 1-0 nylon sutures, resulting in the complete reconstruction of the posterior supporting elements of the spinal column.


RESULTS
En bloc laminoplasty was performed on 16 patients via a T-saw; most of the patients had intradural spinal tumors. The patients did not need their spinal canals to be enlarged after the intradural procedure had been performed. The follow-up period ranged from 2 to 40 months (mean +/- standard error, 22.6 +/- 3.4 mo). The laminoplasty was performed from the upper cervical to the sacral regions, although the most frequently operated level was the lower thoracic level. Two-level laminoplasty was performed in 12 patients, and three-level laminoplasty was performed in four. The laminoplasty was done safely and without any complications, except in one patient, who experienced thoracic root injury from a T-saw that was accidentally inserted anterior to the roots. No spinal column deformity or sinking of the replaced laminar flap was noted during the follow-up period; patients were assessed at follow-up via radiographs or computed tomographic scans. Computed tomographic scans obtained later indicated that bony fusion occurred at the cutting edges 1.0 to 4.0 months after surgery (mean, 1.90 +/- 0.34 mo).


CONCLUSIONS
Simple en bloc laminoplasty performed with a T-saw is a useful, safe procedure that can be used to reconstruct the posterior spinal elements throughout the whole spinal region after the intradural procedure has been performed.
Hara
M
M
Department of Neurosurgery, Nagoya University School of Medicine, Japan.
Takayasu
M
M
Takagi
T
T
Yoshida
J
J
D000328:Adult; D000368:Aged; D002574:Cervical Vertebrae / Q000601:surgery; D005260:Female; D006801:Humans; D007796:Laminectomy; D008159:Lumbar Vertebrae / Q000601:surgery; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D019635:Neurosurgical Procedures / Q000295:instrumentation*; D013118:Spinal Cord Diseases / Q000601:surgery; D013131:Spine / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery*; D013904:Thoracic Vertebrae / Q000601:surgery; D014057:Tomography, X-Ray Computed