Laminoplasty is the Preferred Procedure for a Posteriorly Based Multilevel Surgery in a Patient With a Neutral Spine and Cervical Spondylotic Myelopathy: True or False?
Cervical laminoplasty was introduced as a surgical intervention for cervical myelopathy primarily to address some of the shortcomings of laminectomy for the same indication.1 Laminectomy had been associated with several unique complications including postlaminectomy kyphosis,2–4 recurrent cord compression secondary to epidural scar formation,5 and neurological deterioration.6 Two main varieties of laminoplasty exist, “French door” and “open door” variants, with several modifications to each procedure developed over the past two decades. Regardless of technique, the primary goal is spinal cord decompression achieved both directly by removal of the posterior elements and indirectly through posterior cord drift away from compressive anterior pathology.
Numerous studies have confirmed successful neurological recovery following all types of laminoplasties with no one technique proving superior. These outcomes are sustainable and have been confirmed at long term follow up.7–10 Most studies report neurological recovery in terms of modified JOA scores and those reports have shown improvements of approximately 70%.11,12 A meta-analysis reviewing all studies on laminoplasty from 2003–2013 found that among all studies, with average follow up of 44 months (±35.1 mo), the mean improvement in JOA score was from 9.91 (±1.65) to 13.68 (±1.05).13 That same study concluded “unanimously that the laminoplasty procedure achieves its primary goal: to make neurological recovery possible by decompressing the spinal cord.”
With a proven track record of good outcomes, cervical laminoplasty is our preferred technique for cases of cervical spondylotic myelopathy, including instances such as described in the stem, mainly, such as in cases of neutral cervical spine alignment. The advantages of laminoplasty over other techniques such as posterior laminectomy and fusion include some preserved range of motion, a negated possibility of pseudarthrosis, a lower risk of infection and reoperation,14 no need for postoperative immobilization, and the potential for easier revision having left a remnant “roof” over the spinal cord.
Some have questioned whether laminopalsty is an effective technique for spinal cord decompression in the setting of kyphotic or even neutral cervical alignment. In theory, a kyphotic alignment may not allow for posterior cord drift with posterior decompression alone as the spinal cord is “draped” over the posterior aspect of the vertebral bodies. Alternatively, a lordotic alignment lends itself to cord shift with decompression alone as the cord may “float” into the newly formed space. Baba et al15 found that this posterior cord drift was essential to successful neurological recovery. They reported that patients experiencing >50% improvement in neurological outcomes showed significant posterior cord migration on MRI compared with those with <50% improvement (P=0.01). Sodeyama et al16 evaluated 95 patients undergoing laminoplasty for CSM and concluded that laminoplasty allowed for cord shifts ranging from 0–6.6 mm and that shifts >3 mm were associated with good outcomes. However, the degree of posterior cord shift was not associated with preoperative cervical alignment. Numerous other studies have been unable to confirm the association between cervical lordosis and improved outcomes and rather, cervical alignment has not been shown to be predictive of poor outcomes.17–19
A landmark paper by Suda et al20 spawned the recommendation not to perform laminoplasty for cases of cervical kyphosis >13 degrees. They reviewed average 5-year (2–13 y) follow up of 154 patients who underwent “French door” laminopalsty for CSM. In terms of risk factors for poor surgical outcomes, preoperative local kyphosis, and signal intensity change in the spinal cord on MRI were the most important.