Surgical Management of C5 Palsy Resulting from Posterior Spinal Decompression for the Treatment of Cervical Spondylotic Myelopathy

Objective: To assess the feasibility of anterior cervical procedures in the treatment of C5 palsy occurring after posterior cervical decompression procedures done for the treatment of cervical spondylotic myelopathy. Introduction: In this study we hypothesized that anterior cervical decompression would benefit these patients through widening the cervical foramen, directly by rongeurs and drills and indirectly by placing an intervertebral spacer (cervical cage). The aim of the study is to assess whether a more proactive approach would benefit these patients. Materials and methods: Between January 2005 and September 2011, 200 posterior cervical procedures have been done by the authors, for the treatment of cervical spondylotic myelopathy (CSM). The procedures done were laminectomy with or without instrumentation. Forty cases developed C5 palsy postoperatively (20%). 20 cases (50%) presented immediate postoperatively and the rest presented during the first week postoperatively. All the cases started a course of conservative treatment of steroids, analgesics and physiotherapy. Thirty patients (75%) improved on conservative treatment. Ten patients did not improve after more than one year of conservative management. Two cases had a single level anterior cervical discectomy and cage fusion (ACDF), 3 cases had single level ACDF with plate fixation and 3 cases had 2 levels ACDF with plate fixation. Two cases had 3 levels ACDF with interbody fusion and plate fixation. The operative choice was made in order to increase the lordotic curve and the foraminal diameter. Results: Immediately postoperatively all patients had improved radicular pain. Assessment of the motor power was made immediately postoperative and 3 months afterwards with continuous physiotherapy. There was no change in the C5 palsy in all cases on the immediate postoperative examination, whereas all cases showed improvement of at least 2 grades in the 3 months postoperative visits. All patients at the final follow up had an MMT (Manual Muscle Test) grade of at least 3. Six patients reached an MMT grade of 4 or more. One case had recurrent myelopathy 9 months after 3 levels ACDF and fixation. His MRI showed adjacent segment degeneration at a higher level and had led to myelopathy. He improved on conservative treatment. Two cases died during follow up period: one at 10 months postoperatively from complications of massive myocardial infarction and the other one 15 months postoperatively from bronchogenic carcinoma diagnosed 7 months after surgery. Conclusion: Postoperative C5 palsy following posterior decompression for cervical spondylotic myelopathy is not an uncommon occurrence and the majority of cases will respond to conservative treatment. Anterior decompression procedures may offer a safe and effective solution for those few patients who do not respond to a prolonged period of conservative management. *Corresponding author: Khaled Saoud, Assistant Professor, Department of Neurosurgery, Faculty of Medicine, Ain Shams University, Consultant Neurosurgeon, Arab Contractors Hospital, Cairo, Egypt, E-mail: ksaoud@yahoo.com Received November 27, 2012; Accepted January 16, 2013; Published January 18, 2013 Citation: Saoud K, El-Shehaby A, El-Shazly A (2013) Surgical Management of C5 Palsy Resulting from Posterior Spinal Decompression for the Treatment of Cervical Spondylotic Myelopathy. J Spine 2: 132. doi:10.4172/2165-7939.1000132 Copyright: © 2013 Saoud K, et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.


Introduction
Posterior decompression procedures are commonly performed in the treatment of multiple level cervical compressive spondylotic myelopathy. These include laminectomy alone, laminoplasty alone and laminectomy/laminoplasty with posterior instrumentation. C5 palsy following cervical laminectomy for cervical spondylosis was first reported by Scoville [1] and Stoops and King [2]. It has also been reported after other posterior-based techniques. The incidence varies from 0-50% depending on the technique used, how the condition is defined and which patient group is being analysed [3,[4][5][6][7][8]9,10]. Takemitsu et al. [11] reported a higher incidence among patients undergoing instrumentation than those treated by laminoplasty alone.
Several etiologies have been proposed to explain this phenomenon including direct root injury, posterior spinal cord drift, spinal cord ischemia, reperfusion injury and segmental cord affection [4,[7][8][9]. Additional instrumentation is suspected of increasing the incidence of C5 palsy through iatrogenic foraminal stenosis [12,5,6,10] and added tension in the spinal cord and roots caused by correcting the spinal alignment [6,10]. Also in some instances it may be multifocal [9].
No specific treatments have been suggested for postoperative C5 palsy. Mainly conservative management has been advocated for these cases [7,13] with varying degrees of recovery and latency to recovery.
In this study we hypothesized that anterior cervical decompression would benefit these patients through widening the cervical foramen, directly by rongeurs and drills and indirectly by placing an intervertebral spacer (cervical cage). The aim of the study is to assess whether a more proactive approach would benefit these patients. fusion (ACDF), 3 cases had single level ACDF with plate fixation and 3 cases had 2 levels ACDF with plate fixation. Two cases had 3 levels ACDF with interbody fusion and plate fixation. The operative choice was made in order to increase the lordotic curve and the foraminal diameter. The primary operative goal was to perform foraminotomy at C4-5 level; however, since we performed a fusion technique in C4-5 level, we operated on any degenerated levels adjacent to this level in order to reduce the incidence of future need of reoperation.

Clinical results
Immediately postoperatively all patients had improved radicular pain. Assessment of the motor power was made immediately postoperative and 3 months afterwards with continuous physiotherapy. There was no change in the C5 palsy in all cases on the immediate postoperative examination, whereas all cases showed improvement of at least 2 grades in the 3 months postoperative visits. All patients at the final follow up had an MMT grade of at least 3. Six patients reached an MMT grade of 4 or more. Motor power improvement is shown in table 1.
One case had recurrent myelopathy 9 months after 3 levels ACDF and fixation. His MRI showed adjacent segment degeneration at a higher level led to myelopathy (Figures 1 and 2). He improved on conservative treatment. Two cases died during follow up period one at 10 months postoperatively from complications of massive myocardial infarction and the other one 15 months postoperatively from bronchogenic carcinoma diagnosed 7 months after surgery.

Radiological results
All cases had plain radiographs to assess fusion in 3 months postoperatively. Eight cases out of 10 (80%) had solid fusion at three months postoperatively. One case had solid fusion in the 6 months postoperatively. The last patient had pseudoarthrosis, but refused a redo surgery as he was clinically intact.

Discussion
The incidence of postoperative C5 palsy following posterior

Clinical data
Between January 2005 and September 2011, 200 posterior cervical procedures have been done by the authors, for the treatment of cervical spondylotic myelopathy (CSM). The procedures done were laminectomy with or without instrumentation. Forty cases developed C5 palsy postoperatively (20%). 20 cases (10%) presented immediate postoperatively and the rest presented during the first week postoperatively. An MRI was done once C5 palsy was detected to exclude intraspinal pathology such as hematoma or cord injury.
C5 palsy, in general, was defined as postoperative occurrence of paralysis of the deltoid muscle with no deterioration of myelopathy. In patients who had preoperative deltoid paralysis, C5 palsy was considered when manual muscle test (MMT) of the deltoid showed worsening of 1 or more grades, postoperatively.
All the cases started a course of conservative treatment of steroids, analgesics and physiotherapy. Thirty patients (75%) improved on conservative treatment. Ten patients did not improve after more than one year of conservative management. The average age among the ten patients included in this study was 63 years (55-72 years). There were 8 males and 2 females.
For the sake of avoiding confusion certain definitions will be assigned to the occurrence of C5 palsy according to its relation to the corrective surgery. Post posterior decompression C5 palsy (PPDCP) refers to C5 palsy occurring after posterior decompression surgery. While, post anterior decompression C5 palsy (PADCP) refers to the status of the C5 palsy after corrective anterior decompression. These 10 cases presented by radicular pain of C5 distribution and variable degrees of motor weakness. We did not usually tend to operate on cases of mild weakness. The degree of PPDCP and PADCP was graded in our study using the manual muscle test (graded from 0 to 5, with 0 as no movement and power and 5 with normal strength). The PPDCP in five of the studied cases was grade 0 (2 immediately and 3 over one week period), 3 were grade 1 and 2 were grade 2. cervical decompression for CSM has been reported to average 4.6% (range 0%-30%) [7][8][9]11,13,14]. The incidence of C5 palsy in this study is comparable at 20%. Generally, the recommendation for initial management of these cases is conservative management with a recovery rate ranging from 71% to 96% according the MMT grade [9]. Similarly, 75% of the patients in this study improved on conservative management alone.

Two cases had a single level anterior cervical discectomy and cage
Based on the assumption that the pathology in these cases is nerve root traction due to posterior cord shift following decompression surgery, several studies have suggested that prophylactic foraminotomy at the time of posterior decompression surgery would benefit these patients [15][16][17]. In addition, many cases have preexisting foraminal stenosis so foraminotomy would also be beneficial from this aspect.
To the best of our knowledge this study is first to report the surgical management of cases that had already developed C5 palsy following posterior decompression surgery, and had not improved on conservative treatment. We believe that the major pathology in these cases is at the root level, also as evidenced by the decreased incidence of C5 palsy reported when additional foraminotomy was performed with the posterior decompression [15]. Thus in addition to being able to decompress the root from the anterior approach, the insertion of an interbody cage would widen the foramen further and relieve any additional compression. Moreover, this theoretically would reduce the incidence of kyphosis following cervical laminectomy which ranges from 6% to 47% [18][19][20][21].
Neurological improvement was observed in all the patients postoperatively in spite of a latent period of at least one year from the time of the occurrence of the C5 palsy. Although the possibility that the neurological improvement may have been part of the natural course of the disease cannot be excluded, the occurrence of this improvement in all patients and in such a short period after surgery would make it more likely to be the result of the surgery.

Conclusion
PPDCP is not an uncommon occurrence and the majority of cases will respond to conservative treatment. Anterior decompression procedures may offer a safe and effective solution for those few patients who do not respond to a prolonged period of conservative management.