The aims of laminoplasty are to expand the spinal canal, to secure spinal stability, and to preserve the protective function of the spine. Preservation of spinal mobility is also the goal of this procedure.
Nuchal muscles and spinal ligaments which were totally or partially detached to expose laminae can be reat-tached to preserved posterior spinal structures, and this may prevent development of the cervical instability which often happens after laminectomy, particularly in those subjects below 50 years of age. The spared laminae preserve the protective function of the spine, shielding the spinal cord from pressure from hematoma during the early postoperative period and preventing the invasion of scar tissue subsequent to hematoma in the late convalescent period. Development of kyphosis in combination with a thick peridural scar following laminectomy is a notorious cause of late neurological deterioration in laminectomy.
1. Basically, no instrument needs to be inserted into the canal for laminotomy. Furthermore, the site of the lamino-
tomy or hinge for laminoplasty is uniformly at the junction of the lamina and facet, whereas in laminectomy the site of the laminotomy is variable. Both these factors make laminoplasty more predictable and safer.
2. Expansion of the spinal canal is obtained without much loss of spinal stability, as mentioned above.
3. Decompression of the spinal cord is accomplished without removal of spondylotic protrusion impinging on the neural tissue. Removal of the osteocartilaginous protrusion or ossified ligament encroaching on the already compromised neural tissue is known to be the most hazardous part of the procedure when surgeons use the anterior approach to treat CSM and OPLL respectively.
4. Supplementary procedures for nerve root decompression or reinforcement of spinal stability can easily be performed. Facetectomy for nerve root decompression is optional except for the facets on the hinge side of the laminae. Bone grafting for stabilization either in single or multiple segments is easily applicable.
1. Upper extremity palsy. Details are described in the complications section.
2. Neck discomfort. The incidence of neck pain after lamino-plasty is reported to be high, and this is one of the most discouraging complications . The pathomechanism of postoperative neck discomfort has not yet been clarified, although several hypotheses have been advocated such as prolonged neck immobilization, facet joint damage, and nuchal muscle damage.
3. Reduction of mobility of the cervical spine. Although preservation of spinal mobility is one of the aims of lamino-plasty, the range of motion (ROM) usually decreases by 30-70% of the preoperative range. This becomes more marked when laminotomy or hinges are located at the facet in either expansive open-door laminoplasty or spin-ous process splitting laminoplasty.
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