Cervical Spondylotic Myelopathy: A Review of the Evidence




Cervical spondylotic myelopathy (CSM) is the most common progressive spinal cord disorder in patients more than 55 years old. This disease is also the most common cause of acquired spasticity in later life and may lead to progressive spasticity and neurologic decline. This article explores some of the controversies about CSM and reviews pertinent articles, specifically prospective and randomized clinical trials when possible, to obtain the cleanest and least biased data. The 4 current controversial topics that surround CSM are: (1) natural history of mild CSM; (2) surgical approach: anterior versus posterior; (3) laminoplasty or laminectomy; and (4) cervical arthroplasty for CSM.


Cervical spondylotic myelopathy (CSM) is the most common progressive spinal cord disorder in patients more than 55 years old. More than 50% of middle-aged patients show radiographic evidence of cervical disease, but only 10% have clinically significant root or cord compression. CSM is also the most common cause of acquired spasticity in later life and may lead to progressive spasticity and neurologic decline. There are multiple symptoms of myelopathy, including motor and sensory disturbances, but the onset is usually insidious. Lower extremities are affected first, and patients can complain of gait disturbance, with degeneration of the spinocerebellar and corticospinal tracts. The upper extremities can then become affected with loss of coordination and difficulty with fine motor tasks. However, the symptoms can be much more subtle and may involve axial neck pain, scapular pain, or a progressive broad-based gait. Often, the patient’s spouse notices the disturbance earliest as an unfamiliar walking pattern.


Goals


This article explores some of the controversies in CSM and reviews pertinent articles, specifically prospective and randomized clinical trials when possible, to obtain the cleanest and least biased data. The 4 current controversial topics that surround CSM are: (1) natural history of mild CSM; (2) surgical approach: anterior versus posterior; (3) laminoplasty or laminectomy; and (4) cervical arthroplasty for CSM.




Natural history


The natural history of CSM is not well known. Historically surgical treatment has been the mainstay for progressive CSM. Traction and soft collars have not been shown to alter the natural course of the disease. There have been several series studying patients treated conservatively, and 26% to 50% of patients may deteriorate neurologically over time. Clark and Robinson found that 5% of patients deteriorate quickly, 20% have a gradual but steady decline in function, and 70% have a stepwise progression in their symptoms with variable periods of quiescent disease. 4 These patients are also at increased risk of sustaining severe neurologic injuries with even minor trauma. Minor trauma can result in a central cord syndrome or in quadriplegia without fracture or dislocation. Early treatment has also been shown to alter the prognosis in patients. treated within 1 year of onset of symptoms.


In 1992, Rowland wrote an editorial for Neurology entitled Surgical treatment of CSM: time for a controlled trial. In the article, he pleaded for a randomized controlled trial to study the outcome of these patients. He noted that often patients can be successfully treated nonoperatively and the only way to determine the appropriate surgical intervention and timing, was to conduct a controlled trial. The Cochrane review searched the literature in 2002 and found only 1 randomized controlled trial from 2000 with a 2-year follow-up that specifically addressed the conservative versus operative management of mild CSM. They were unable to draw any conclusions based on that study ( Table 1 ).



Table 1

Conservative treatment of cervical spondylotic myelopathy


























































Study Level of Evidence Type of Study Number of Patients Inclusion Criteria f/u Time Outcomes Conclusions
Kadanka et al, 2000 II Prospective randomized (coin toss) 48 (21 surgical, 27 conservative) mJOA ≥ 12, age < 75 y, MRI evidence of compression, no previous surgery 2 y No change in mJOA, no change in walking No difference
Kadanka et al, 2002 II Prospective randomized (coin toss) 68 (35 conservative, 33 surgical-ACDF 22, corpectomy 6, laminoplasty 5) mJOA ≥ 12, younger than 75 y, MRI evidence of compression, no previous surgery 3 y No change in mJOA, no change in walking No advantage
Sampath et al, 2000 III Prospective questionnaire 62 (31 surgery) f/u for 43/62 (70%) > 8 wk CSM symptoms, radiographic evidence, age > 18 y 11.2 mo (8–13) Surgery with improved functional status, neurologic status, = greater satisfaction Surgery improved outcomes
Matsumoto et al, 2000 III Retrospective 52 CSM, MRI evidence of compression 3 y (1–6) No change in JOA, 70% satisfactory results No difference
Nakamura et al, 1998 IV Retrospective 64 CSM, > 1 year f/u f/u 3–10 y No disability in 30% Conservative management is OK

Abbreviations: ACDF, anterior cervical discectomy and fusion; f/u, follow-up; mJOA, modified Japanese Orthopedic Association, MRI, magnetic resonance imaging.


That study was expanded and now has 3-year follow-up data. Those 2 studies are the only randomized controlled studies that attempt to determine the role of surgical intervention for mild CSM. The 3-year study by Kadanka and colleagues followed 68 patients prospectively in a randomized controlled trial, and no patients were lost to follow-up. Randomization was accomplished by a coin toss and patients were randomized to surgical decompression or conservative management. Conservative management consisted of a soft collar, nonsteroidal antiinflammatory drugs (NSAIDS), and discouragement from high-risk activities. Surgical management was at the surgeon’s discretion. The inclusion criteria were mild myelopathy, that is, modified Japanese Orthopedic Association (mJOA) score greater than 12, younger than 75 years, and evidence of cervical compression on magnetic resonance imaging (MRI). The disease in these patients was mild; the median cord compression was 71 mm 2 , and most had only 1 level disease for a median duration of 1 year in the nonsurgical group and a median of 3 years in the surgical group. The procedure used for decompression in 67% (22/33) of the patients was a 1-level anterior discectomy and fusion. The outcome measures included mJOA, timed 10-m walk, and evaluation of daily activities that were collected preintervention and at regular postoperative intervals until final follow-up. There were no statistically significant changes in mJOA or walking scores from pre- and postintervention and no significant changes between the operative and nonoperative groups. There was a slight but significant difference in deterioration of the conservatively treated group in their activities of daily living. The investigators’ conclusions were that for mild CSM nonoperative treatment was as effective as surgical decompression, and that patients can be successfully treated nonoperatively for up to 3 years. Although there are some problems with the study (randomization by coin toss), it is a compelling argument for nonoperative management for mild CSM.


A prospective questionnaire was used by Sampath and colleagues for mild CSM treated surgically and nonsurgically. Sixty-two patients were enrolled, however only 43 (69%) completed the study at an average of 11.2 months follow-up (8–13 months). The investigators noted that surgery was associated with improved functional status and improved neurologic status, which correlated directly with patient satisfaction.


Two retrospective studies focused on the long-term outcome of patients with CSM treated nonoperatively. Matsumoto and colleagues reported on 52 patients with an average 3-year follow-up (1–6 years). These patients had 70% satisfaction and no significant deterioration in their JOA scores. Nakamura and colleagues reported on 64 patients with a follow-up of 3–10 years with 30% of patients reporting no disability. The conclusion made by both investigators was that mild CSM could be treated successfully with conservative measures for a significant number of patients. They noted that deterioration may occur over time and these patients need to be followed closely for signs of neurologic injury.


Most investigators suggest that there are multiple factors that play a role in the success of operative or nonoperative management of CSM. Several papers have provided multivariate analysis on the successful operative and nonoperative patients. Their conclusions are similar. Patients may be successfully treated conservatively if they have lower mJOA scores, minimal neurologic findings (normal central motor conduction times), spinal transverse area greater than 70 mm 2 , and are older patients. Surgery was successful for patients with more severe neurologic symptoms, a hyperintense signal on MRI with localized disease and who had canal expansion greater than 40% postoperatively, and were of younger age.


The author’s approach to these patients follows the literature closely. I place a great deal of emphasis on the clinical examination and on the patient’s function. If the disease is mild and the symptoms are mild, I prefer to watch these patients closely with regular scheduled visits. If the patient has significant symptoms of myelopathy, including walking and balance difficulty, poor hand coordination, or progressive neurologic decline, I favor early surgical decompression.




Natural history


The natural history of CSM is not well known. Historically surgical treatment has been the mainstay for progressive CSM. Traction and soft collars have not been shown to alter the natural course of the disease. There have been several series studying patients treated conservatively, and 26% to 50% of patients may deteriorate neurologically over time. Clark and Robinson found that 5% of patients deteriorate quickly, 20% have a gradual but steady decline in function, and 70% have a stepwise progression in their symptoms with variable periods of quiescent disease. 4 These patients are also at increased risk of sustaining severe neurologic injuries with even minor trauma. Minor trauma can result in a central cord syndrome or in quadriplegia without fracture or dislocation. Early treatment has also been shown to alter the prognosis in patients. treated within 1 year of onset of symptoms.


In 1992, Rowland wrote an editorial for Neurology entitled Surgical treatment of CSM: time for a controlled trial. In the article, he pleaded for a randomized controlled trial to study the outcome of these patients. He noted that often patients can be successfully treated nonoperatively and the only way to determine the appropriate surgical intervention and timing, was to conduct a controlled trial. The Cochrane review searched the literature in 2002 and found only 1 randomized controlled trial from 2000 with a 2-year follow-up that specifically addressed the conservative versus operative management of mild CSM. They were unable to draw any conclusions based on that study ( Table 1 ).



Table 1

Conservative treatment of cervical spondylotic myelopathy


























































Study Level of Evidence Type of Study Number of Patients Inclusion Criteria f/u Time Outcomes Conclusions
Kadanka et al, 2000 II Prospective randomized (coin toss) 48 (21 surgical, 27 conservative) mJOA ≥ 12, age < 75 y, MRI evidence of compression, no previous surgery 2 y No change in mJOA, no change in walking No difference
Kadanka et al, 2002 II Prospective randomized (coin toss) 68 (35 conservative, 33 surgical-ACDF 22, corpectomy 6, laminoplasty 5) mJOA ≥ 12, younger than 75 y, MRI evidence of compression, no previous surgery 3 y No change in mJOA, no change in walking No advantage
Sampath et al, 2000 III Prospective questionnaire 62 (31 surgery) f/u for 43/62 (70%) > 8 wk CSM symptoms, radiographic evidence, age > 18 y 11.2 mo (8–13) Surgery with improved functional status, neurologic status, = greater satisfaction Surgery improved outcomes
Matsumoto et al, 2000 III Retrospective 52 CSM, MRI evidence of compression 3 y (1–6) No change in JOA, 70% satisfactory results No difference
Nakamura et al, 1998 IV Retrospective 64 CSM, > 1 year f/u f/u 3–10 y No disability in 30% Conservative management is OK

Abbreviations: ACDF, anterior cervical discectomy and fusion; f/u, follow-up; mJOA, modified Japanese Orthopedic Association, MRI, magnetic resonance imaging.


That study was expanded and now has 3-year follow-up data. Those 2 studies are the only randomized controlled studies that attempt to determine the role of surgical intervention for mild CSM. The 3-year study by Kadanka and colleagues followed 68 patients prospectively in a randomized controlled trial, and no patients were lost to follow-up. Randomization was accomplished by a coin toss and patients were randomized to surgical decompression or conservative management. Conservative management consisted of a soft collar, nonsteroidal antiinflammatory drugs (NSAIDS), and discouragement from high-risk activities. Surgical management was at the surgeon’s discretion. The inclusion criteria were mild myelopathy, that is, modified Japanese Orthopedic Association (mJOA) score greater than 12, younger than 75 years, and evidence of cervical compression on magnetic resonance imaging (MRI). The disease in these patients was mild; the median cord compression was 71 mm 2 , and most had only 1 level disease for a median duration of 1 year in the nonsurgical group and a median of 3 years in the surgical group. The procedure used for decompression in 67% (22/33) of the patients was a 1-level anterior discectomy and fusion. The outcome measures included mJOA, timed 10-m walk, and evaluation of daily activities that were collected preintervention and at regular postoperative intervals until final follow-up. There were no statistically significant changes in mJOA or walking scores from pre- and postintervention and no significant changes between the operative and nonoperative groups. There was a slight but significant difference in deterioration of the conservatively treated group in their activities of daily living. The investigators’ conclusions were that for mild CSM nonoperative treatment was as effective as surgical decompression, and that patients can be successfully treated nonoperatively for up to 3 years. Although there are some problems with the study (randomization by coin toss), it is a compelling argument for nonoperative management for mild CSM.


A prospective questionnaire was used by Sampath and colleagues for mild CSM treated surgically and nonsurgically. Sixty-two patients were enrolled, however only 43 (69%) completed the study at an average of 11.2 months follow-up (8–13 months). The investigators noted that surgery was associated with improved functional status and improved neurologic status, which correlated directly with patient satisfaction.


Two retrospective studies focused on the long-term outcome of patients with CSM treated nonoperatively. Matsumoto and colleagues reported on 52 patients with an average 3-year follow-up (1–6 years). These patients had 70% satisfaction and no significant deterioration in their JOA scores. Nakamura and colleagues reported on 64 patients with a follow-up of 3–10 years with 30% of patients reporting no disability. The conclusion made by both investigators was that mild CSM could be treated successfully with conservative measures for a significant number of patients. They noted that deterioration may occur over time and these patients need to be followed closely for signs of neurologic injury.


Most investigators suggest that there are multiple factors that play a role in the success of operative or nonoperative management of CSM. Several papers have provided multivariate analysis on the successful operative and nonoperative patients. Their conclusions are similar. Patients may be successfully treated conservatively if they have lower mJOA scores, minimal neurologic findings (normal central motor conduction times), spinal transverse area greater than 70 mm 2 , and are older patients. Surgery was successful for patients with more severe neurologic symptoms, a hyperintense signal on MRI with localized disease and who had canal expansion greater than 40% postoperatively, and were of younger age.


The author’s approach to these patients follows the literature closely. I place a great deal of emphasis on the clinical examination and on the patient’s function. If the disease is mild and the symptoms are mild, I prefer to watch these patients closely with regular scheduled visits. If the patient has significant symptoms of myelopathy, including walking and balance difficulty, poor hand coordination, or progressive neurologic decline, I favor early surgical decompression.

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Feb 23, 2017 | Posted by in ORTHOPEDIC | Comments Off on Cervical Spondylotic Myelopathy: A Review of the Evidence
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