脊髓型颈椎病外科治疗的远期疗效评价
作者：贾连顺 袁文 倪斌 陈德玉 宋滇文 陈雄生
单位：贾连顺(第二军医大学长征医院骨科， 上海 200003)；袁文(第二军医大学长征医院骨科， 上海 200003)；倪斌(第二军医大学长征医院骨科， 上海 200003)；陈德玉(第二军医大学长征医院骨科， 上海 200003)；宋滇文(第二军医大学长征医院骨科， 上海 200003)；陈雄生(第二军医大学长征医院骨科， 上海 200003)
关键词：颈椎病，脊髓型；外科手术
第二军医大学学报000703 [摘要] 目的：研究脊髓型颈椎病经前路减压及植骨融合术后的远期疗效及其影响因素。方法：对245例脊髓型颈椎病患者，实施颈前路减压及自体髂骨移植融合，其中31例于术后6个月至4年再次手术。术后随访5-15年，平均随访时间6.8年。结果：术后功能评价，优118例(48.16%)，良71例(28.98%)，可35例(14.29%)及差21例(8.57%)。根据40分评分法，36-40分者101例，31-35分者54例，平均提高8分。结论：脊髓型颈椎病外科治疗远期效果是肯定的；手术时机、病理变化程度及手术技术等对治疗效果有明显影响。
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[中图分类号] R 681.55 [文献标识码] A
Evaluation of long-term outcome of surgical treatment for cervical spondylotic myelopathy
JIA Lian-Shun YUAN Wen NI Bin CHEN De-Yu SONG Dian-Wen CHEN Xiong-Sheng (Department of Orthopaedics, Changzheng Hospital, Second Military Medical University, Shanghai 200003,China)
[ABSTRACT] Objective: To investigate the long-term outcome of anterior decompression and bone graft fusion for cervical spondylotic myelopathy(CSM) and factors affecting the outcome. Methods: Two hundred and forty-five patients with CSM were treated with anterior cervical decompression and auto iliac bone graft fusion, of whom 31 had a second operation between 4 months and 2 years after operation. Follow-up studies were carried out within 5 to 15 years after operation, averaging 6.8 years. Results: Function evaluation: excellent in 118 cases (48.16%), good in 71 (28.98%), passable in 35 (14.29%) and poor in 21 (8.57%). According to the 40 points score method, there was an average of 8 point increase in all cases, of which 101 were between 36 to 40 points, 54 between 31 to 35 points. Conclusion: The long-term outcome of surgical treatment for CSM is definite. Significant factors affecting the outcome include timing of operation, degree of pathology and technique of surgery.
, 百拇医药
[KEY WORDS] spondylotic myelopathy， cervical; surgery,operative
[Article Code] 0258-879X(2000)07-0605-05
The etiology and pathogenesis of cervical spondylotic myelopathy (CSM) are too sophisticated to gain an unanimous opinion. The incidence and course of this disease has its own natural history. The long-term outcome of surgical treatment of CSM are affected by many factors. A series of systemic retrospective studies were performed in 245 cases of CSM during 5-15 years after operation. The timing of surgical intervention, the postoperative pathologic changes and the main factors affecting the outcome are discussed.
, 百拇医药
1 MATERIALS AND METHODS
1.1 Subjects A total of 245 patients, 197 males and 48 females, aged from 29-40 years, including 33 from 29 to 74 years, 78 from 41 to 50 years, 103 from 51 to 60 years, 25 from 61 to 70 years and 6 from 71 to 74 years.
1.2 Pathogenesis and history The condition progressed slowly in 98 patients without evident, 47 showed a sudden onset and progressed rapidly. Fifty-one cases were induced by slight head trauma, and 33 by tiredness and progressed slowly. Sixteen patients were attacked during sleep. The duration of this condition averaged 13 months (range, 7 days-15 years): 7 days-3 months in 44 cases, 3-4 years in 21, 5-6 years in 14 and 6-15 years in 18.
, 百拇医药
1.3 Radiographic findings
X-ray：The plain radiographs of anterior-posterior view, lateral view and flexion-extension dynamic view were examined routinely in this group. The basal characteristic of this disease included decreament or absence of the physiological lordosis of the cervical spine and narrowing of intervertebral space. One hundred and fifty-four patients had developmental stenosis of the spine canal (Pavlov rate < 0.75). Seventy-six patients showed instability of the segments involved. Twenty-eight patients had co-existing local (single segment) OPLL. Seventy-six patients showed extensive degeneration involving more than 3 vertebrae. Ninety-five patients showed wedge-shaped or fan-shaped changes of the vertebrae.
, 百拇医药
CT scan：Of the 135 patients who underwent CT scan 127 had denaturation and herniation of the cervical intervertebral discs as well as osteophyte formation, 28 had simple osteophyte formation, and 28 had OPLL co-existing with disc herniation and osteophyte formation, all in single segment.
MRI examination：Of the 214 patients who underwent MRI 207 had denaturation and herniation of the discs as well as osteophyte formation. Among them, 27 showed clamp-like compressed cord by hypertrophy of ligamentum flavum which invaginated into the canal. Fourty-three patients showed cord deformation and diminution in T2 weighted images and signal enhancement in pathologic segments.
, 百拇医药
1.4 Surgical intervention Anterior decompression and iliac bone autografting were performed with trepan procedure or subtotal vertebrae ectomy in this group. Lock plates were applied in 25 patients. The surgical segment distribution included C3-4 in 31 cases, C3-5 in 20 cases, C4-5 in 61 cases, C4-6 in 22 cases, C5-6 in 73 cases, C5-7 in 24 cases, and C6-7 in 14 cases.
Thirty-one patients in this group underwent a second operation within 6 months to 4 years after the first operation. Among them, 7 patients received anterior extensive decompression and bone grafting fusion, 6 patients underwent posterior laminae formation, 13 patients received semi-laminae ectomy and 5 patients received total laminae ectomy.
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2 RESULTS
All patients in this group were followed up continuously from 5.5 years to 15 years, averaging 6.8 years. Among them, 145 patients were followed up for 5-6 years, 74 patients for 7-8 years, 17 patients for 9-10 years and 9 patients for 11-15 years. The outcomes were evaluated synthetically according to radiographic findings, self-sensation and clinical function.
2.1 Radiographic evaluation The plain radiographs of anterior-posterior view, lateral view and flexion-extension dynamic view were performed routinely. Findings: (1) 98 patients showed physiological lordosis of the cervical spine recovered to normal or nearly-normal status. Eighty-eight patients showed decreament of the physiologic lordosis. Thirty-eight patients showed absence of the lordosis with the straight cervical spine. Twenty-one patients showed cervical kyphosis. (2) Bonic union was obtained in all patients on the segment of surgical decompression and fusion. (3) Forty-seven patients showed dynamic instability between adjacent vertebrae, including upper vertebrae instability in 28 cases and lower vertebrae instability in 19 cases. Thirty-one patients showed distinct osteophyte formation. (4) The sagittal canal diameters of the operated segments measured on X-ray films were (12±0.57)mm in 178 cases, (11±0.83)mm in 34 cases, and <(10±0.92)mm in 33 cases. One hundred and eighty-two patients underwent a second MRI examination. Findings: 153 patients showed lack of distinct compressing substances in the canal of operated segments. Eleven patients showed slender cord and enhanced responses. Eighteen patients showed disc degeneration and herniation in adjacent vertebraes and osteophyte formation causing the dura and cord compression.
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2.2 Clinical function evaluation Excellent: 118 patients (48.16%) showed normal or nearly-normal motor function of the upper and lower limbs, satisfied self-sensation, lack of pain, normal defecation function and competent for light work and life self-support. Good: 71 patients (28.98%) showed significantly improved motor function, good self-sensation, easy to fatigue, sometimes acratia of the extremities, life self-support. Passable: 35 patients (14.29%) showed limited motor function, fingers weakness, tumbling due to acratia of the lower extremities, walk relying on canes support, approximate life self-support and sometimes needed help. Among them, 15 patients deteriorated back to the preoperative condition 2 years later, although they had significant functional improvement during 1-2 years after operation. Deterioration: 21 patients showed unsteady gaits, handhold weakness, and incapability of fine action; they had to be confined to bed.
, 百拇医药
The results of evaluation with the 40 scores method (according to the criteria set at Qingdao conference) showed 36-40 scores in 101 cases, 31-35 scores in 54, 26-30 scores in 35, 21-25 scores in 14, 16-20 scores in 23 and 16-20 scores in 18. The scores of 17 patients declined by 3-5 scores as compared with the preoperative evaluation. The maximal increasing scores was 18, averaging 8 scores.
2.3 The relationship between the course of disease and the outcome of surgical treatment The present study demonstrated that there was an important correlation between the course of disease and the outcome of surgical treatment (Table 1).
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Tab 1 Correlation between course of disease
and outcome of surgical treatment Time
Treated cases
Excellent and good cases (%)
<6 months
119
103 (86.6%)
7-12 months
42
35 (83.3%)*
, 百拇医药
1-2 years
31
20 (64.5%)**
>3 years
53
31 (58.5%)**
* P<0.05, ** P<0.01 vs <6 months group3 DISCUSSION
3.1 The factors affecting the long-term outcome of surgical treatment of CSM The clinic observations on surgical treatment of CSM patients in recent 20 years have demonstrated the positive therapeutic effect of releasing cord compression by section of the compressing substances in the canal[1-3]. With the studies going into the center stage, the application of electrophysiological examination and the progress in radiography, especially the wide use of high-resolution MRI provide the qualitative and orientative evidence of early diagnosis of CSM and patho-anatomic foundation for the choice of surgical techniques.
, 百拇医药
When should surgical treatment be selected for CSM? And how to decide the timing of operation? Most of the studies indicated that surgical treatment should be performed as soon as the diagnosis of CSM was made[4]. However, some researchers considered that surgical intervention wasn't the only treatment since a certain proportion of the CSM patients had a self-stabilization and self-limited course[5]. According to the results of this group, surgical treatment had assured effects on ending the deterioration of the signs and preventing the progression of the disease, although it is not the exclusive choice. Not all CSM patients cannot detect the disease by themselves since it developed progressively and cryptically. Many patients were attacked suddenly. For instance, paraplegia was often caused by slight trauma, which affected the outcome of treatment. Many authors suggested that surgical treatment should be applied at the beginning of a clinical attack to decrease the duration of non-operative treatment and observation to the greatest extent. Blind delay would result in losing the best operative time.
, 百拇医药
The present study demonstrated that there was some correlation between the course of disease and the outcome of surgical treatment. The longer the disease course was, the more severe the disease would turn to be. However, the outcome of the disease progression vary greatly from individual to individual, since the natural prognostic tendency of the disease is different between individual patients. A few patients had a history of repeated attacks. Their clinical signs and symptoms would remain benign and not aggravate significantly. However, most of the patients would deteriorate rapidly and intensively after the onset. Some patients presented repeated attacks and deteriorated progressively, indicating a continuous deterioration course. Therefore, CSM should receive short-term treatment with non-operative or heteropathy methods after early diagnosis, such as resting, immobilization, physiotherapy and pharmacotherapy, as well as careful follow-up observation. The duration of non-operative therapy should not exceed 3-6 months. If clinical symptoms developed continuously, surgical treatment should be performed in order to release cord compression at an early stage to restore the stability of the spine and to impede the progression of the disease.
, 百拇医药
The procedures and the techniques of surgical treatment are the foundation to obtain the affirmative results. Most of the compressing substances in CSM patients come from the anterior part of the cervical canal. In some cases, the cord is compressed by anterior and posterior compressing substances simultaneously, which are formed by dynamic factors, e.g. the degeneration and herniation of the discs and osteophyte formation, together with the degeneration of the ligamentum flavum which invaginated into the canal, resulting in stenosis of sagittal diameter of the canal. Anterior section of the compressing substances is the primary choice. All patients who received a second operation had pathologic changes in more than 3 segments or combined with generative stenosis of the canal. Seven patients underwent a second anterior operation for spared or regenerated compressing substances after the first anterior operation. Twenty-four patients underwent posterior decompression.
, 百拇医药
The main purpose of surgical treatment is direct section of the compressing substances causing cord compression, such as bonic compressing substances including osteophyte and the posterior hyperplastic edge of the vertebraes, as well as fibrous compressing substances including intervertebral discs herniation, fibrous ring and broken nucleus pulposus. The blood-supply of the cord will improve or be compensated after decompression, and therefore the main cause of CSM may be received.
, 百拇医药
The operative sites for decompression should be selected according to the signs and symptoms, together with radiographic features. Single segmental decompression and fusion is performed if only one segment is involved. In those with involvement 2 segments, either decompression and fusion made in individual segments, or subtotal vertebrae resection and long window shape decompression between these 2 segments is performed. We do not recommend to extend the range of surgical decompression over those segments with degenerated discs or slight disc herniation, in order to avoid excessive loss of motor unit, declining of motor function and degeneration of adjacent vertebraes induced by the changes of load and stress distribution. Most authors had confirmed this result, which was regarded as one of the important factors affecting long-term treatment outcomes.
, 百拇医药
The operation with excessive decompression range, including all osteophytes at the posterior edge of the vertebrae and the inner side of the vertebral arch, is called subtotal vertebrae ectomy by Okada et al [6] . This so-called subtotal vertebrae ectomy indicates the section part of the vertebrae in front of the canal, not including the 2 sides of the vertebrae.
The intervertebral height should be maintained through bone grafting or /and internal fixation. Therefore, the size of the grafting bone should be 2 mm greater than the space prepared for grafting and it should have 2 or 3 sides of cortex bone in order to avoid the decline of the height of the front column during bonic union. In fact, the intervertebral height cannot always be maintained persistently only by bone grafting since the effect of the stress will play a role in the biomechanics function of cervical spine.
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The features of the disease have important effects on the long-term outcomes of the surgical treatment. A series of studies have suggested that cord compression could result in demyelination of the white matter in the cord, and secondary cord ischemia as well, especially cord necrosis induced by embolism of cord anterior artery[7]. Mechanical compression and blood supply disturbance could occur individually or concurrently. Intrinsic muscular atrophy of the hands represents the injury of anterior horn cells of the cord, which cannot be improved by surgical treatment.
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The presence of multimuscular spasm and atrophy of the extremities intrinsic muscular atrophy of hands and staggering gait or need for lying in bed represent the irreversible severe stage of cord injury and loss of the best timing for operation. The effects of surgical treatment will be affected greatly in this situation.
3.2 The choice of operative route The purpose of surgical decompression is to remove the compressing substances causing the cord compression and injury. The pathological changes of CSM mainly come from the anterior side of the canal, including degenerated and herniated discs and osteophyte at the posterior edge of the vertebrae[8]. Therefore, we selected anterior operation as the main surgical procedure. However, it was found in recent studies that herniated discs could shrink or disappear by themselves after posterior decompression. In the case of generative canal stenosis coexisting with CSM, anterior decompression should be performed since not all the canal had pathological changes and compressing substances existed in a certain segment or several segments[9，10]. In the case of hypertrophy of ligamentum flavum which invaginated into the canal, posterior decompression should be selected primarily, and whether anterior surgery is performed should depend on the particular situation.
, 百拇医药
The number of segments receiving fusion affected the long-term outcome treatment. Some authors have found that the discs near the fusion segment may accelerate the course of degeneration, herniation and loss of stability, since the motor compensation phenomenon will result in load enhancement and stress concentration in the normal segments. Clinical morbidity would occur if these injuries are severe enough. The cause of the morbidity of the recidivity CSM is always due to inadequate decompression and spared compressing substances during the first operation. In fact, the changes are always neglected by the patients since they progress slowly and the patients are always too old to act generally.
, 百拇医药
The problem how to decrease and prevent the degeneration of the adjacent vertebral discs after anterior decompression and bone grafting fusion need further studies.
Biography:JIA Lian-Shun,professor,trtor of doctor.
Foundatin：This project is supporrted by Shanghai Leading Subject of Key Medical Science Foundation.NO.1995-Ⅳ-008,1998-Ⅳ-008.
[REFERENCES]
[1] Kang JD, Bohlman HH. Cervical spondylotic myelopathy[J]. Curr Opin Orthop, 1996, 7(2):13-17.
, 百拇医药
[2] Law MD Jr, Bernhardt M, White AA, et al. Evaluation and management of cervical spondylotic myelopathy[J]. Instr course lect,1995,44:99-110.
[3] 贾连顺， 倪 斌， 袁 文, 等. 脊髓型颈椎病的再认识[J].第二军医大学学报，1997，18(6)：503-506.
[4] Matsuyama Y, Kawakami N, Mimatsu K. Spinal cord expansion after decompression in cervical myelopathy[J]. Spine, 1995,20(15):1657-1663.
[5] Nakamura K, Kurokawa T, Hoshino Y, et al. Conservative treatment for cervical spondylotic myelopathy: achiecvement and sustainability of a level of “no disability”[J]. J Spinal Disord, 1998,11(2):175-179.
, 百拇医药
[6] Okada K, Shirasaki N, Hayashi H, et al. Treatment of cervical spondylotic myelopathy by enlargement of the spinal canal anteriorly followed by arthrodesis[J]. J Bone Joint Surg Am, 1991,73:352-357.
[7] Al-Mefty O, Harkey HL, Marawi I, et al. Experimental chronic compressive cervical myelopathy[J]. J Neurosurg,1993,79(4)：550-561.
[8] Teramoto T, Ohmori K, Takatsu T, et al. Long-term results of the anterior cervical spondylodesis[J]. Neurosurgery, 1994,35(1):64-68.
, 百拇医药
[9] Goto S, Mochizuki M, Watanabe T, et al. Long-term follow-up study of anterior surgery for cervical spondylotic myelopathy with special reference to magnetic resonance imaging findings in 52 cases[J]. Clin Orthop, 1993,(291):142-153.
[10] Emery SE, Bohlman HH, Bolesta MJ, et al. Anterior cervical decompression and arthrodesis for the treatment of cervical spondylotic myelopathy[J]. J Bone Joint Surg Am, 1998,80(7):941-951.
Received 2000-02-22
Accepted 2000-05-29, 百拇医药
单位：贾连顺(第二军医大学长征医院骨科， 上海 200003)；袁文(第二军医大学长征医院骨科， 上海 200003)；倪斌(第二军医大学长征医院骨科， 上海 200003)；陈德玉(第二军医大学长征医院骨科， 上海 200003)；宋滇文(第二军医大学长征医院骨科， 上海 200003)；陈雄生(第二军医大学长征医院骨科， 上海 200003)
关键词：颈椎病，脊髓型；外科手术
第二军医大学学报000703 [摘要] 目的：研究脊髓型颈椎病经前路减压及植骨融合术后的远期疗效及其影响因素。方法：对245例脊髓型颈椎病患者，实施颈前路减压及自体髂骨移植融合，其中31例于术后6个月至4年再次手术。术后随访5-15年，平均随访时间6.8年。结果：术后功能评价，优118例(48.16%)，良71例(28.98%)，可35例(14.29%)及差21例(8.57%)。根据40分评分法，36-40分者101例，31-35分者54例，平均提高8分。结论：脊髓型颈椎病外科治疗远期效果是肯定的；手术时机、病理变化程度及手术技术等对治疗效果有明显影响。
, http://www.100md.com
[中图分类号] R 681.55 [文献标识码] A
Evaluation of long-term outcome of surgical treatment for cervical spondylotic myelopathy
JIA Lian-Shun YUAN Wen NI Bin CHEN De-Yu SONG Dian-Wen CHEN Xiong-Sheng (Department of Orthopaedics, Changzheng Hospital, Second Military Medical University, Shanghai 200003,China)
[ABSTRACT] Objective: To investigate the long-term outcome of anterior decompression and bone graft fusion for cervical spondylotic myelopathy(CSM) and factors affecting the outcome. Methods: Two hundred and forty-five patients with CSM were treated with anterior cervical decompression and auto iliac bone graft fusion, of whom 31 had a second operation between 4 months and 2 years after operation. Follow-up studies were carried out within 5 to 15 years after operation, averaging 6.8 years. Results: Function evaluation: excellent in 118 cases (48.16%), good in 71 (28.98%), passable in 35 (14.29%) and poor in 21 (8.57%). According to the 40 points score method, there was an average of 8 point increase in all cases, of which 101 were between 36 to 40 points, 54 between 31 to 35 points. Conclusion: The long-term outcome of surgical treatment for CSM is definite. Significant factors affecting the outcome include timing of operation, degree of pathology and technique of surgery.
, 百拇医药
[KEY WORDS] spondylotic myelopathy， cervical; surgery,operative
[Article Code] 0258-879X(2000)07-0605-05
The etiology and pathogenesis of cervical spondylotic myelopathy (CSM) are too sophisticated to gain an unanimous opinion. The incidence and course of this disease has its own natural history. The long-term outcome of surgical treatment of CSM are affected by many factors. A series of systemic retrospective studies were performed in 245 cases of CSM during 5-15 years after operation. The timing of surgical intervention, the postoperative pathologic changes and the main factors affecting the outcome are discussed.
, 百拇医药
1 MATERIALS AND METHODS
1.1 Subjects A total of 245 patients, 197 males and 48 females, aged from 29-40 years, including 33 from 29 to 74 years, 78 from 41 to 50 years, 103 from 51 to 60 years, 25 from 61 to 70 years and 6 from 71 to 74 years.
1.2 Pathogenesis and history The condition progressed slowly in 98 patients without evident, 47 showed a sudden onset and progressed rapidly. Fifty-one cases were induced by slight head trauma, and 33 by tiredness and progressed slowly. Sixteen patients were attacked during sleep. The duration of this condition averaged 13 months (range, 7 days-15 years): 7 days-3 months in 44 cases, 3-4 years in 21, 5-6 years in 14 and 6-15 years in 18.
, 百拇医药
1.3 Radiographic findings
X-ray：The plain radiographs of anterior-posterior view, lateral view and flexion-extension dynamic view were examined routinely in this group. The basal characteristic of this disease included decreament or absence of the physiological lordosis of the cervical spine and narrowing of intervertebral space. One hundred and fifty-four patients had developmental stenosis of the spine canal (Pavlov rate < 0.75). Seventy-six patients showed instability of the segments involved. Twenty-eight patients had co-existing local (single segment) OPLL. Seventy-six patients showed extensive degeneration involving more than 3 vertebrae. Ninety-five patients showed wedge-shaped or fan-shaped changes of the vertebrae.
, 百拇医药
CT scan：Of the 135 patients who underwent CT scan 127 had denaturation and herniation of the cervical intervertebral discs as well as osteophyte formation, 28 had simple osteophyte formation, and 28 had OPLL co-existing with disc herniation and osteophyte formation, all in single segment.
MRI examination：Of the 214 patients who underwent MRI 207 had denaturation and herniation of the discs as well as osteophyte formation. Among them, 27 showed clamp-like compressed cord by hypertrophy of ligamentum flavum which invaginated into the canal. Fourty-three patients showed cord deformation and diminution in T2 weighted images and signal enhancement in pathologic segments.
, 百拇医药
1.4 Surgical intervention Anterior decompression and iliac bone autografting were performed with trepan procedure or subtotal vertebrae ectomy in this group. Lock plates were applied in 25 patients. The surgical segment distribution included C3-4 in 31 cases, C3-5 in 20 cases, C4-5 in 61 cases, C4-6 in 22 cases, C5-6 in 73 cases, C5-7 in 24 cases, and C6-7 in 14 cases.
Thirty-one patients in this group underwent a second operation within 6 months to 4 years after the first operation. Among them, 7 patients received anterior extensive decompression and bone grafting fusion, 6 patients underwent posterior laminae formation, 13 patients received semi-laminae ectomy and 5 patients received total laminae ectomy.
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2 RESULTS
All patients in this group were followed up continuously from 5.5 years to 15 years, averaging 6.8 years. Among them, 145 patients were followed up for 5-6 years, 74 patients for 7-8 years, 17 patients for 9-10 years and 9 patients for 11-15 years. The outcomes were evaluated synthetically according to radiographic findings, self-sensation and clinical function.
2.1 Radiographic evaluation The plain radiographs of anterior-posterior view, lateral view and flexion-extension dynamic view were performed routinely. Findings: (1) 98 patients showed physiological lordosis of the cervical spine recovered to normal or nearly-normal status. Eighty-eight patients showed decreament of the physiologic lordosis. Thirty-eight patients showed absence of the lordosis with the straight cervical spine. Twenty-one patients showed cervical kyphosis. (2) Bonic union was obtained in all patients on the segment of surgical decompression and fusion. (3) Forty-seven patients showed dynamic instability between adjacent vertebrae, including upper vertebrae instability in 28 cases and lower vertebrae instability in 19 cases. Thirty-one patients showed distinct osteophyte formation. (4) The sagittal canal diameters of the operated segments measured on X-ray films were (12±0.57)mm in 178 cases, (11±0.83)mm in 34 cases, and <(10±0.92)mm in 33 cases. One hundred and eighty-two patients underwent a second MRI examination. Findings: 153 patients showed lack of distinct compressing substances in the canal of operated segments. Eleven patients showed slender cord and enhanced responses. Eighteen patients showed disc degeneration and herniation in adjacent vertebraes and osteophyte formation causing the dura and cord compression.
, http://www.100md.com
2.2 Clinical function evaluation Excellent: 118 patients (48.16%) showed normal or nearly-normal motor function of the upper and lower limbs, satisfied self-sensation, lack of pain, normal defecation function and competent for light work and life self-support. Good: 71 patients (28.98%) showed significantly improved motor function, good self-sensation, easy to fatigue, sometimes acratia of the extremities, life self-support. Passable: 35 patients (14.29%) showed limited motor function, fingers weakness, tumbling due to acratia of the lower extremities, walk relying on canes support, approximate life self-support and sometimes needed help. Among them, 15 patients deteriorated back to the preoperative condition 2 years later, although they had significant functional improvement during 1-2 years after operation. Deterioration: 21 patients showed unsteady gaits, handhold weakness, and incapability of fine action; they had to be confined to bed.
, 百拇医药
The results of evaluation with the 40 scores method (according to the criteria set at Qingdao conference) showed 36-40 scores in 101 cases, 31-35 scores in 54, 26-30 scores in 35, 21-25 scores in 14, 16-20 scores in 23 and 16-20 scores in 18. The scores of 17 patients declined by 3-5 scores as compared with the preoperative evaluation. The maximal increasing scores was 18, averaging 8 scores.
2.3 The relationship between the course of disease and the outcome of surgical treatment The present study demonstrated that there was an important correlation between the course of disease and the outcome of surgical treatment (Table 1).
, http://www.100md.com
Tab 1 Correlation between course of disease
and outcome of surgical treatment Time
Treated cases
Excellent and good cases (%)
<6 months
119
103 (86.6%)
7-12 months
42
35 (83.3%)*
, 百拇医药
1-2 years
31
20 (64.5%)**
>3 years
53
31 (58.5%)**
* P<0.05, ** P<0.01 vs <6 months group3 DISCUSSION
3.1 The factors affecting the long-term outcome of surgical treatment of CSM The clinic observations on surgical treatment of CSM patients in recent 20 years have demonstrated the positive therapeutic effect of releasing cord compression by section of the compressing substances in the canal[1-3]. With the studies going into the center stage, the application of electrophysiological examination and the progress in radiography, especially the wide use of high-resolution MRI provide the qualitative and orientative evidence of early diagnosis of CSM and patho-anatomic foundation for the choice of surgical techniques.
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When should surgical treatment be selected for CSM? And how to decide the timing of operation? Most of the studies indicated that surgical treatment should be performed as soon as the diagnosis of CSM was made[4]. However, some researchers considered that surgical intervention wasn't the only treatment since a certain proportion of the CSM patients had a self-stabilization and self-limited course[5]. According to the results of this group, surgical treatment had assured effects on ending the deterioration of the signs and preventing the progression of the disease, although it is not the exclusive choice. Not all CSM patients cannot detect the disease by themselves since it developed progressively and cryptically. Many patients were attacked suddenly. For instance, paraplegia was often caused by slight trauma, which affected the outcome of treatment. Many authors suggested that surgical treatment should be applied at the beginning of a clinical attack to decrease the duration of non-operative treatment and observation to the greatest extent. Blind delay would result in losing the best operative time.
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The present study demonstrated that there was some correlation between the course of disease and the outcome of surgical treatment. The longer the disease course was, the more severe the disease would turn to be. However, the outcome of the disease progression vary greatly from individual to individual, since the natural prognostic tendency of the disease is different between individual patients. A few patients had a history of repeated attacks. Their clinical signs and symptoms would remain benign and not aggravate significantly. However, most of the patients would deteriorate rapidly and intensively after the onset. Some patients presented repeated attacks and deteriorated progressively, indicating a continuous deterioration course. Therefore, CSM should receive short-term treatment with non-operative or heteropathy methods after early diagnosis, such as resting, immobilization, physiotherapy and pharmacotherapy, as well as careful follow-up observation. The duration of non-operative therapy should not exceed 3-6 months. If clinical symptoms developed continuously, surgical treatment should be performed in order to release cord compression at an early stage to restore the stability of the spine and to impede the progression of the disease.
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The procedures and the techniques of surgical treatment are the foundation to obtain the affirmative results. Most of the compressing substances in CSM patients come from the anterior part of the cervical canal. In some cases, the cord is compressed by anterior and posterior compressing substances simultaneously, which are formed by dynamic factors, e.g. the degeneration and herniation of the discs and osteophyte formation, together with the degeneration of the ligamentum flavum which invaginated into the canal, resulting in stenosis of sagittal diameter of the canal. Anterior section of the compressing substances is the primary choice. All patients who received a second operation had pathologic changes in more than 3 segments or combined with generative stenosis of the canal. Seven patients underwent a second anterior operation for spared or regenerated compressing substances after the first anterior operation. Twenty-four patients underwent posterior decompression.
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The main purpose of surgical treatment is direct section of the compressing substances causing cord compression, such as bonic compressing substances including osteophyte and the posterior hyperplastic edge of the vertebraes, as well as fibrous compressing substances including intervertebral discs herniation, fibrous ring and broken nucleus pulposus. The blood-supply of the cord will improve or be compensated after decompression, and therefore the main cause of CSM may be received.
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The operative sites for decompression should be selected according to the signs and symptoms, together with radiographic features. Single segmental decompression and fusion is performed if only one segment is involved. In those with involvement 2 segments, either decompression and fusion made in individual segments, or subtotal vertebrae resection and long window shape decompression between these 2 segments is performed. We do not recommend to extend the range of surgical decompression over those segments with degenerated discs or slight disc herniation, in order to avoid excessive loss of motor unit, declining of motor function and degeneration of adjacent vertebraes induced by the changes of load and stress distribution. Most authors had confirmed this result, which was regarded as one of the important factors affecting long-term treatment outcomes.
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The operation with excessive decompression range, including all osteophytes at the posterior edge of the vertebrae and the inner side of the vertebral arch, is called subtotal vertebrae ectomy by Okada et al [6] . This so-called subtotal vertebrae ectomy indicates the section part of the vertebrae in front of the canal, not including the 2 sides of the vertebrae.
The intervertebral height should be maintained through bone grafting or /and internal fixation. Therefore, the size of the grafting bone should be 2 mm greater than the space prepared for grafting and it should have 2 or 3 sides of cortex bone in order to avoid the decline of the height of the front column during bonic union. In fact, the intervertebral height cannot always be maintained persistently only by bone grafting since the effect of the stress will play a role in the biomechanics function of cervical spine.
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The features of the disease have important effects on the long-term outcomes of the surgical treatment. A series of studies have suggested that cord compression could result in demyelination of the white matter in the cord, and secondary cord ischemia as well, especially cord necrosis induced by embolism of cord anterior artery[7]. Mechanical compression and blood supply disturbance could occur individually or concurrently. Intrinsic muscular atrophy of the hands represents the injury of anterior horn cells of the cord, which cannot be improved by surgical treatment.
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The presence of multimuscular spasm and atrophy of the extremities intrinsic muscular atrophy of hands and staggering gait or need for lying in bed represent the irreversible severe stage of cord injury and loss of the best timing for operation. The effects of surgical treatment will be affected greatly in this situation.
3.2 The choice of operative route The purpose of surgical decompression is to remove the compressing substances causing the cord compression and injury. The pathological changes of CSM mainly come from the anterior side of the canal, including degenerated and herniated discs and osteophyte at the posterior edge of the vertebrae[8]. Therefore, we selected anterior operation as the main surgical procedure. However, it was found in recent studies that herniated discs could shrink or disappear by themselves after posterior decompression. In the case of generative canal stenosis coexisting with CSM, anterior decompression should be performed since not all the canal had pathological changes and compressing substances existed in a certain segment or several segments[9，10]. In the case of hypertrophy of ligamentum flavum which invaginated into the canal, posterior decompression should be selected primarily, and whether anterior surgery is performed should depend on the particular situation.
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The number of segments receiving fusion affected the long-term outcome treatment. Some authors have found that the discs near the fusion segment may accelerate the course of degeneration, herniation and loss of stability, since the motor compensation phenomenon will result in load enhancement and stress concentration in the normal segments. Clinical morbidity would occur if these injuries are severe enough. The cause of the morbidity of the recidivity CSM is always due to inadequate decompression and spared compressing substances during the first operation. In fact, the changes are always neglected by the patients since they progress slowly and the patients are always too old to act generally.
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The problem how to decrease and prevent the degeneration of the adjacent vertebral discs after anterior decompression and bone grafting fusion need further studies.
Biography:JIA Lian-Shun,professor,trtor of doctor.
Foundatin：This project is supporrted by Shanghai Leading Subject of Key Medical Science Foundation.NO.1995-Ⅳ-008,1998-Ⅳ-008.
[REFERENCES]
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[2] Law MD Jr, Bernhardt M, White AA, et al. Evaluation and management of cervical spondylotic myelopathy[J]. Instr course lect,1995,44:99-110.
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[6] Okada K, Shirasaki N, Hayashi H, et al. Treatment of cervical spondylotic myelopathy by enlargement of the spinal canal anteriorly followed by arthrodesis[J]. J Bone Joint Surg Am, 1991,73:352-357.
[7] Al-Mefty O, Harkey HL, Marawi I, et al. Experimental chronic compressive cervical myelopathy[J]. J Neurosurg,1993,79(4)：550-561.
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[9] Goto S, Mochizuki M, Watanabe T, et al. Long-term follow-up study of anterior surgery for cervical spondylotic myelopathy with special reference to magnetic resonance imaging findings in 52 cases[J]. Clin Orthop, 1993,(291):142-153.
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Received 2000-02-22
Accepted 2000-05-29, 百拇医药