Original Article Prognosis of Cervical Degenerative Myelopathy after Multilevel Anterior Cervical Discectomies and Fusion

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1 Egyptian Journal of Neurosurgery Volume 9 / No. / January - March Original Article Prognosis of Cervical Degenerative Myelopathy after Multilevel Anterior Cervical Discectomies and Fusion Ahmed M Zaater*, Mohamed I Refaat Department of Neurosurgery, School of Medicine, Cairo University ARTICLE INFO Received: 5 February 4 Accepted: March 4 Keywords: Multilevel cervical discs Cervical spondylotic myelopathy JOA score PEEK cage. ABSTRACT Background: Over time, degenerative changes become more common in the cervical spine and may represent normal aging. Cervical spondylotic myelopathy (CSM) is one of the common sequelae of this degenerative process. The treatment of choice for multilevel cervical myelopathy remains under investigation. Objective: In this study, we will evaluate the outcome after multilevel anterior decompression and fusion. Patients & Method: Twenty patients of cervical spondylotic myelopathy caused by multilevel cervical discs were included in this study. All cases failed to respond to conservative measures for at least two months. Patients were assessed clinically and radiologically before surgery, immediately after surgery and at the final follow up period within a minimum of three months. They were operated upon by multilevel anterior decompression and fusion using PEEK cages. Results: 9 % of our patients showed improvement, regarding their clinical symptoms, % of case didn t show any improvement. None of our cases showed deterioration than their preoperative state. Factors like pre-operative clinical state, duration of symptoms, and age were found to have a direct influence on post-operative improvement. On the other hand factors like smoking, comorbidities, pre-operative cord signal in TWI MRI and number of levels operated wasn t found to have influence on recovery. Conclusion: multilevel anterior decompression can reliably stop myelopathy progression in multilevel cervical myelopathy and lead to significant neurologic recovery and neck pain reduction in a majority of patients. 4 Egyptian Journal of Neurosurgery. Published by MEDC. All rights reserved INTRODUCTION Cervical myelopathy includes a wide range of symptoms and signs including motor and sensory abnormalities related to dysfunction of the cervical spinal cord. Spondylosis is the degenerative changes that occur in the spine, including degeneration of joints, ligaments and connective tissue of the cervical vertebrae, as well as the discs. This process adds stress on the articular cartilage of the vertebrae and their respective end plates. Osteophytic spurs develop at the margins of these end plates. The disc also calcifies aiming to stabilize the vertebrae. 5 Patients with CSM will generally present with: neck stiffness; deep aching neck, arm, or shoulder pain; and stiffness or clumsiness while walking. Some patients will have signs and symptoms of both radiculopathy and myelopathy. Loss of sphincter control or frank incontinence is a rare presentation 5,4. MRI is the procedure of choice during the initial screening process of patients with suspected CSM. Hypo intense signals in TWI seen in the spinal cord of patients with *Corresponding author: Ahmed M Zaater Department of Neurosurgery, School of Medicine, Cairo University neurozaatar@hotmail.com, Tel: +/8675 signals in TWI seen in the spinal cord of patients with CSM may indicate myelomalacia or permanent spinal cord damage. CT is complementary to MRI; it gives accurate assessment of the amount of canal stenosis because it is superior to MRI in evaluating bone. An absolute stenosis is sagittal canal diameter < mm and a relative stenosis is canal diameter < mm. The normal sagittal diameter in the mid-cervical spine of an adult is 7 8 mm,,. With patients who are mildly affected by CSM, a conservative approach can be taken. A variety of nonsurgical strategies can be utilized with variable success for the treatment of CSM. These include cervical immobilization, physical therapy and medical treatment. Once frank myelopathy occurs, surgical intervention is recommended. The primary aim of surgery is to decompress the spinal cord, thus giving the neural elements more room. Traditionally, cervical laminectomy was used for surgical treatment of CSM. However, over the past years, it has been increasingly noticed that laminectomy is not appropriate for all patients. Further neurologic deterioration after laminectomy is caused by the development of latent instability of the spine with development of kyphotic spinal deformities. For this reason, anterior approaches Egyptian Journal of Neurosurgery 57

2 to the spine are used. Through an anterior cervical approach, one can remove osteophytes and disc material for decompression of the spinal cord, maintain normal curvature, or correct the curve when needed 8,4. OBJECTIVE The aim of this work to evaluate the outcome of cervical degenerative myelopathy after multilevel anterior cervical decompression and fusion PATIENTS & METHODS This study was conducted on patients presenting with CSM due to multilevel cervical disc degenerative disease (two or more levels) with anterior compression at the levels of the affected disc spaces. All cases tried conservative treatment for at least two months before going to surgical treatment. A full Clinical history was taken for all cases. Full preoperative and postoperative neurological examination was also done for all cases. The modified Japanese Orthopedic Association (mjoa) evaluation system for cervical myelopathy was utilized (Table ). Table : The modified Japanese Orthopedic Association (mjoa) evaluation system for cervical myelopathy I. Motor function of the upper extremity: Inability to move hands Inability to eat with a spoon but able to move hands Inability to button shirt but able to eat with a spoon Able to button shirt with great difficulty Able to button shirt with slight difficulty No dysfunction II. Motor function of the lower extremity: Complete loss of motor and sensory function Sensory preservation without ability to move legs Able to move legs but unable to walk Able to walk on flat floor with a walking aid Able to walk up and/or down stairs with hand rail Moderate to significant lack of stability but able to walk up and/or Down starirs without hand rail Mild lack of stability but walk unaided with smooth reciprocation No dysfunction III. sensation: Complete loss of hand sensation Severe sensory loss or pain Mild sensory loss No sensory loss IV. Sphincter dysfunction score: Inability to micturate voluntarily Marked difficulty with micturition Mild to moderate difficulty with micturition Normal micturition Score (point) Operative technique: General anesthesia was used. The fluoroscope was used to identify the levels. The closest skin crease to the desired discs levels was identified. A horizontal incision allowed access to multiple levels by widely opening the sternocleidomastoid fascia. Classic microscopic anterior cervical discectomy and fusion (ACDF) was performed for all the affected levels. Adequate decompression of the spinal cord and both nerve foramina was done. A hollow Polyetheretherketone (PEEK) cage filled with autologous bone was used for bony fusion. Anterior cervical plate was used in cases with severe kyphotic deformity to add more stability to the spine. Follow-up: Immediate post-operative and at - months intervals postoperative evaluation with modified JOA scores assessment. The mean follow-up period was months (range 5- months). Immediate and late post-operative X-ray, and/or MRI was performed. Clinical evaluation after surgery was evaluated by using mjoa score and recovery rate obtained by the formula suggested by Hirabayashi, and is considered excellent ( 75%), good (74 5%), fair (49 5%), unchanged (4 %) and worsened (score less than %) Egyptian Journal of Neurosurgery

3 Recovery rate (RR) % = Post-operative score Pre-operative score Full score (7) pre-operative score. x % RESULTS The data collected from cases of surgically managed multilevel cervical disc disease was analyzed. Age of patients ranged between 9 years and 64 years. The mean age was 54. years and standard deviation (SD) was.55. Sex: 6 males (8%), and 4 females (%). Occupation: more than half of our cases (65%) were heavy mechanical workers (table ). Smoking: 55% of our patients were smokers, against 45% nonsmokers. Comorbidity: % of our cases were diabetics, % were hypertensive, % had ischemic heart disease, and % were HCV positive. While 4% didn t have any comorbidity. Number of levels operated: 6% of our patients ( cases) have two levels, 4% (8 cases) have three levels operated and no patients have more than three levels Table : Occupation of all cases Frequency % Manual worker 9 45 Driver 5 Teacher Cook 5 Engineer 5 Accountant Secretary 5 Physician 5 Total Duration of symptoms ranged from 6 months to 5 years, mean was 4.7 months and SD was.5. Preoperative mjoa scores ranged from 8 to 4, with a mean of.9 and SD of.5. Thirteen of our cases (65%) had a hyper intense cord signal on TWI in their preoperative MRI. Post-operative mjoa scores ranged from to 7, with a mean of 4.45 and the SD of.46.recovery rate: % of cases showed excellent recovery, % remained unchanged, while none of our cases worsened (table ). Table : Recovery rate in cases Recovery rate No. of cases Excellent (75%-%) 4 (%) Good (5%-74%) 9 (45%) Fair (49%-5%) 5 (5%) Un-changed (4%-%) (%) Worsen (less than %) The relation between recovery rate and variables: The prognosis was affected by age of patient; younger patients have good prognosis than older ones (fig. ). There was no statistical relation between sex and prognosis (p-value.66 by unpaired t test). Concerning smoking and other comorbidities; there was no statistical significance on their affection on recovery rates. The duration of symptoms was inversely proportional to the prognosis (fig. ). There was also no statistical significance in recovery rate between patients with cord signal on MRI and patients who has no cord signals (p-value.4 by unpaired t test). Cases with higher pre-operative score were associated with better prognosis (fig. ). The mean recovery rate was slightly higher in patients with two levels (mean ) operated than that with three levels (mean 48.5) affected with no statistical significance (p-value.8 by unpaired t test). Fig. : correlation between recovery rate and age of patients Fig. : correlation between recovery rate and duration of symptoms Egyptian Journal of Neurosurgery 59

4 Fig. : correlation between recovery rate and preoperative mjoa DISCUSSION Anterior cervical discectomy and fusion is the gold standard treatment for cervical disc herniation, it can be also utilized safely in removal of cervical cord compression in multilevel cervical disc disease leading to cervical spondylotic myelopathy. Our study was conducted upon patients with cervical spondylotic myelopathy managed with anterior cervical discectomy with fusion to identify the recovery rates and also look for the pre-operative prognostic factors and their effect on post-operative recovery rate. The mean age of the cases in our study was 54. years and 8% of our cases were males. This numbers are matching with many of previous studies and literature review. The study by Yarbrough et al has a mean age of 55 years and 75% of cases were males. 6 It was clear in our preoperative assessment of patients, that multilevel cervical discs leading to myelopathy could be related to the patient s occupation, most of our cases were heavy mechanical workers, rather than jobs not involved with muscular activities, 65% for heavy workers and 5% for non-muscular work. As regards the recovery rate (According to the mjoa score for evaluation of the results of operation for cervical myelopathy), 4 cases (%) showed excellent recovery, 9 cases (45%) good recovery, 5 cases (5%) fair recovery, cases (%) showed no recovery, while no cases showed deterioration in their pre-operative score. This is an overall success rate of 9%. Most of the recent literature that focused on outcomes for Anterior Cervical Discectomy with Fusion (ACDF) gave short- and long-term clinical success in the range of 67% to %. Ebersold et al. reported Nurick scale outcomes in patients with multilevel ACDF. Six-month outcomes showed improvements of 7% and long-term improvement of 55% 6. Yue et al. reviewed 7 patients, after an average of 7. years, who had anterior cervical discectomy and fusion with allograft and plating. Patients reported improvement in axial neck pain (95.5%), radicular arm pain (95.4%), upper extremity weakness (8.7%), and gait problems (%). 7 In our study we found that age of the patient, duration of symptoms, pre-operative mjoa score affected the recovery rate. While factors like sex, occupation, smoking, comorbidities, pre-operative MRI cord signal and number of levels operated didn t have an influence on recovery rate. Martin et al. had a retrospective analysis of clinical results in 5 consecutive patients surgically treated for cervical myelopathy with multilevel ACDF. They had 64% overall recovery rate. They stated age, duration of symptoms, MRI cord signal, as well as preoperative clinical state as the most important prognostic factors. 9 In another study published by Chiles et al, it was noted that the most important factors for successful outcome in patients treated for cervical spondylotic myelopathy are the patient's age and the duration of symptoms. Young patients tend to do better than elderly patients. With respect to duration of disease, patients whose disease has been present for fewer than 6 months have a more favorable outcome than patients whose symptoms have been present for year. In the study by Mastronardi et al he noted that intramedullary spinal cord changes in signal intensity in patients with CSM can be reversible (hyperintensity on T-weighted imaging) or nonreversible (hypointensity on T-weighted imaging). The regression of areas of hyperintensity on T-weighted imaging is associated with a better prognosis, whereas the T-weighted hypointensity is an expression of irreversible damage and, therefore, the worst prognosis. Fig. 4: Pre and post-operative images of a 5 years old male patient with double level cervical disc, presenting with neck pain and spastic left lower limb. After double level ACDF, patient showed recovery rate 65% 6 Egyptian Journal of Neurosurgery

5 Fig. 5: Pre and post-operative images of a 6 years old female patient with neck pain, and spastic Paraparesis, post-operative X-ray after three levels ACDF, patient had 5% recovery rate Fig. 6: Pre and post-operative images of 4 years old male patient with straightened cervical curve, presenting with spastic both lower limbs, X-ray after ACDF and plate fixation, recovery rate 75%. CONCLUSION Multilevel anterior cervical decompression can reliably stop myelopathy progression in multilevel cervical myelopathy caused by multiple discs compressions, leading to significant neurologic recovery and pain reduction in a majority of patients. Factors of age, duration of symptoms, and pre-operative neurological state were found to be influential to the prognostic factors. While on the opposite hand, factors of sex, smoking, comorbidities, preoperative hyper intense signal on TWI MRI and number of levels operated didn t show statistical impact on the recovery rates. REFERENCES. Benzel EC, Lancon J, et al: Cervical laminectomy and dentate ligament section for cervical spondylotic myelopathy. J Spinal Disord. 4:86-95, Chiles BW, Leonard MA, et al: Cervical spondylotic myelopathy: patterns of neurological deficit and recovery after anterior cervical decompression. Neurosurgery 44(4):76-9, Darren R.Lebl, Alex Hughes, et al: Cervical spondylotic myelopathy: pathophysiology, clinical presentation, and treatment. HSS J 7(): 7 78,. 4. Dillin WH: Cervical Spine: Clinical Syndromes in Cervical Myelopathy. The Spine; by Saunders, Elsevier chapter 46:784-79, the fifth edition, Fehlings MG, Skaf G: A review of the pathophysiology of cervical spondylotic myelopathy with insights for potential novel mechanisms drawn from traumatic spinal cord injury. Spine :7 7, Galbraith JG, Butler JS, et al: Operative outcomes for cervical myelopathy and radiculopathy. Adv Orthop: 995,. 7. Hirabayashi K, Miyakawa J, Satomi K, Maruyama T, Wakano K. Operative results and postoperative progression of ossification of the longitudinal ligament. Spine 6:54-64, Kadanka Z, Bednarik J, et al.: Conservative treatment versus surgery in spondylotic cervical myelopathy: a prospective randomized study. Eur Spine J. 9:58 544,. 9. Martin R, Carda JR, et al: Cervical myelopathy: retrospective analysis of surgical results in 5 cases treated by anterior cervical discectomy and interbody fusion. Neurocirugia (astur). 5():5-55, 5.. Mastronardi L, Elsawaf A, et al: Prognostic relevance of the postoperative evolution of intramedullary spinal cord changes in signal intensity on magnetic resonance imaging after anterior decompression for cervical spondylotic myelopathy. J Neurosurg Spine. 7:65-, 7.. Morishita Y, Naito M, et al.: The relationship between the cervical spinal canal diameter and the pathological changes in the cervical spine. Eur Spine J. 8:877 88, 9.. Rowe J: Diagnostic imaging and degenerative syndromes of the cervical spine. In Giles LGF and Singer KP (eds.): Clinical anatomy and management of cervical spine pain. Reed Educational and professional publishing Ltd. volume : 89-, Shin JJ: Intramedullary high signal intensity and neurological status as prognostic factors in cervical spondylotic myelopathy. Acta Neurochir (Wien). 5(): ,. 4. Sonntag VK: Anterior cervical discectomy. Neurosurgery. 49:99-9,. 5. William F Young: Cervical Spondylotic Myelopathy: A Common Cause of Spinal Cord Dysfunction in Older Persons. Am Fam Physician. ; 6(5):64-7,. Egyptian Journal of Neurosurgery 6

6 6. Yarbrough CK, Murphy RK, et al: The natural history and clinical presentation of cervical spondylotic myelopathy. Adv Orthop.: 4864,. 7. Yue WM, Brodner W, et al: Long-term results after anterior cervical discectomy and fusion with allograft and plating. A 5- to -year radiologic and clinical follow-up study. Spine. vol., no. 9: 8 44,5. 6 Egyptian Journal of Neurosurgery