Does hinge sidedness influence laterality of C5 palsy after expansile open-door cervical laminoplasty?

ABSTRACT

OBJECTIVE: Cervical expansile open-door laminoplasties (EOLPs) have an open side and a hinge side, with the open side being bridged by grafts or miniplates. The authors explored the possibility that the open-door side might have a greater incidence of C5 palsy due to a greater stretch of the ipsilateral C5 nerve root. METHODS: This study was a retrospective review of prospectively collected data over a period of 25 years specifically assessing surgical complications. Included were patients who underwent EOLP for myelopathy, radiculopathy, or mild central cord injuries (American Spinal Injury Association Impairment Scale [AIS] grade D). Exclusion criteria included preexisting C5 weakness; patients with AIS grade A, B, or C injury; and added instrumentation or additional surgical procedures. Patients were monitored postoperatively for C5 palsy or any other complications. A comparison group included patients who underwent cervical laminectomy and fusion (CLF). RESULTS: A total of 327 laminoplasties were collected, and 31 patients were excluded because of severe spinal cord injury (AIS grades A-C), 3 for preoperative C5 weakness, and 21 for instrumentation or additional surgical procedures. Thus, 272 patients were analyzed with a mean age of 59.9 years (range 22-88 years). Diagnoses at presentation were cervical myelopathy (84.1%), central cord syndrome (7.2%), cervical myeloradiculopathy (3.4%), ossification of the posterior longitudinal ligament (1.9%), and other (3.4%). The most common complications were C5 palsy (n = 7, 2.6%) and wound infection (n = 7, 2.6%). Of the 7 cases of postoperative C5 palsies in this study, 6 occurred on the side of the open door. Of the C5 palsies, 2 were mild, 3 were moderate, and 2 were severe. Two of the 7 C5 palsies had a delayed (> 24 hours) onset. The C5 palsy incidence after CLF was 2.7% with no side preference. CONCLUSIONS: C5 palsy after cervical decompression for myelopathy is a known occurrence, with a rate of 2.6% in the current study. The authors found that C5 palsies more commonly occur on the open side of the laminoplasty. This could be due to a greater manipulation of the nerve root on the side of the open door or greater stretch of the C5 root on the open-door side. If clinical symptoms and anatomical stenosis are symmetric, the authors recommend creating the laminoplasty hinge on the patient's dominant side to minimize potential loss of dominant proximal arm function.