Motor palsy after posterior cervical foraminotomy-Anatomical considerations- Kyung Chul Choi; Yong Ahn; Byung Uk Kang; Sang-Ho Lee MD PhD Department of Neurosurgery, Wooridul Spine Hospital, Seoul, Korea

Introduction Results Anatomically, the C5 nerve root is Fig 1. Incidence of motor palsy after Posterior cervical foraminotomy (PCF) Three of 133 (2.3%) levels that thinner and covers the entire posterior cervical foraminotomy by is a good surgical technique for underwent PCF developed a motor intervertebral disc at a relatively operative level treating radiculopathy caused by palsy (Table 1). Two cases involved sharper angle than the other nerve foraminal stenosis or posterolateral the C5 nerve root and 1 case involved roots [4]. The removal of an extruded herniation. Although PCF has the the C6 nerve root. The cause of the disc at C4-5 forces more excessive advantages of avoiding complications C5 palsy may have been excessive retraction of the C5 nerve root. associated with the anterior approach retraction, whereas the cause of the and cervical fusion, PCF has several C6 palsy may have been thermal Conclusions disadvantages, including a limited damage caused by drilling. The rate of Although PCF is a good alternative surgical indication, postoperative neck C5 palsy (22.2%) was much higher treatment with minimal morbidity for pain, the progression of kyphosis, and than that observed in other nerves cervical radiculopathy, surgeons should the potential development of a motor (Fig 1). keep in mind the possibility of motor palsy. Motor palsy is a serious Case Discussion palsy, especially at C4-5. complication that can result from A 66-year-old woman presented with To the best our knowledge, the cervical surgery. We introduce cases right arm pain. MR images showed incidences of postoperative C5 palsy Learning Objectives of motor palsy after posterior cervical foraminal stenosis at C3-4 and after cervical spine anterior and Posterior cervical foraminotomy is a foraminotomy (PCF) and consider foraminal stenosis and posterolateral posterior surgery are 4.7% and 4.3% good alternative treatment for cervical cervical anatomy. disc herniations at C4-5. We on average [1]. Over the past few radiculopathy. We consider anatomy of performed PCF at C3-4 and C4-5. The years, many hypotheses of etiology of cervical root and disc space to prevent C5 nerve root was entirely overlying Methods C5 palsy have been proposed. Direct iatrogenic neural injury the C4-5 disc space. The nerve root Between January 2007 and August nerve injury, tethering of nerve root 2010, 133 PCFs were performed on was fixed due to dense, perineural, due to spinal cord shifting, local References 106 consecutive patients with fibrous adhesions. After separation of reperfusion injury or double lesion 1.Sakaura H, Hosono N, Mukai Y, et al. radiculopathy caused by foraminal the adhesions with a small blunt hook, hypothesis; co-existing damage of C5 palsy after decompression surgery stenosis or posterolateral disc the extruded disc and bony spur were anterior horn cell in combination with for cervical myelopathy: review of the herniation. removed. This required retraction nerve root lesion [2, 3]. The etiology literature. Spine (Phila Pa 1976) 2003; cranio-medially of the nerve root of C5 palsy after PCF may be different 28:2447-51. through the nerve's axillary portion. from these hypothesis. C5 nerve root Table 1. Clinical characteristics of 2.Hashimoto M, Mochizuki M, Aiba A, et Immediate postoperative weakness is considered to be very susceptible to motor palsy al. C5 palsy following anterior (manual muscle test G I) developed in injury and a major barrier to remove decompression and spinal fusion for the right shoulder on abduction and in of disc. cervical degenerative diseases. Eur the elbow on flexion. MR images Spine J 2010; 19:1702-10. showed a well decompressed level and 3.Saunders RL. On the pathogenesis of no hematoma formation. The patient the radiculopathy complicating FS* : foraminal stenosis, FD†: foraminal was treated with steroids. At 16 multilevel corpectomy. Neurosurgery. disc herniation,ACDF‡: anterior cervical months postoperatively, the elbow 1995 ;37:408-12. discectomy and fusion flexion had much improved, but 4.Hwang JC, Bae HG, Cho SW, et al. shoulder abduction was grade III. Morphometric study of the nerve roots

around the lateral mass for posterior foraminotomy. J Korean Neurosurg Soc 2010; 47:358-64.