Anterior floating method for cervical myelopathy caused by ossification of the posterior longitudinal ligament

Ossification of the posterior longitudinal ligament lessens the sagittal diameter of the cervical canal and compresses the spinal cord anteriorly, and may produce severe disabling myelopathy. The anterior floating method is one of the anterior decompression and reconstructions used in the treatment of cervical myelopathy caused by ossification of the posterior longitudinal ligament. This procedure consists of subtotal resection of vertebral bodies and discs, with slight thinning and release of the ossified ligament using air instrumentation. This is followed by reconstruction of the cervical spine using autogenous strut bone graft accompanied by postoperative application of a halo vest. This method is indicated for patients who present with moderate or severe myelopathies, and especially in those where the canal narrowing ratio exceeds 60%. This radical procedure causes decompression of the spinal cord and restores its function by enlarging the neural canal with anterior migration of the ossified ligament. The procedure minimizes the extent of surgical invasions and avoids damage to the neural tissue, because it does not require the removal of the ossification of the posterior longitudinal ligament. It also stops postoperative regrowth of the ossification. The operative results with long term followup indicate a 71% average recovery rate based on the criteria established by the Japan Orthopedic Association.     

Circumspinal decompression for thoracic myelopathy due to combined ossification of the posterior longitudinal ligament and ligamentum flavum

Ossification of the posterior longitudinal ligament (OPLL) combined with ossification of the ligamentum flavum (OLF) in the thoracic spine can result in serious myelopathy, leading to circumferential compression of the spinal cord in advanced stages of the disease. The authors performed circumspinal decompression (circumferential decompression of the spinal cord) on these patients. This operation consists of two steps: posterior and lateral decompression of the spinal cord by removal of the OLF (first step) and anterior removal of the OPLL for anterior decompression (second step), followed by interbody fusion. In the first step, two deep parallel gutters, covering the extent of the OPLL to be removed anteriorly, are drilled down from the rear into the vertebral body along both sides of the dura to easily and safely remove the OPLL anteriorly at the second step. In the second step, the surgical approach varies according to the affected level; costotransversectomy in the upper thoracic spine and standard thoracotomy in the middle or lower thoracic spine. According to the authors, circumspinal decompression is not an easy procedure, but from their results in 10 patients, they identify it as a radical and promising surgical procedure.     

Total decompression of the spinal cord for combined ossification of posterior longitudinal ligament and yellow ligament in the thoracic spine

Summary One of the causes of hyperostosis in the spinal canal, ossification of the posterior longitudinal ligament (OPLL) combined with ossification of the yellow ligament (OYL) in the thoracic spine, can result in serious myelopathy, leading to sandwich-type compression of the spinal cord from anterior and posterior. For such cases we devised a treatment of total decompression of the spinal cord and intervertebral body fusion. This operation consists of two steps. The first step is designed for posterior and lateral decompression of the spinal cord by removal of the OYL following wide laminectomy. The second step is removal of the OPLL anteriorly for anterior decompression, followed by interbody fusion. As the final procedure of the first step, two deep parallel gutters, covering the extent of the OPLL to be removed anteriorly, are drilled down from the rear into the vertebral body along both sides of the dura. This pretreatment makes removal of the OPLL anteriorly during the second stage much easier, faster, and safer. This operation is lengthy and demanding. However, based on our experience so far, it appears to be a promising surgical procedure.

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Zusammenfassung Die Verknöcherung des Ligamentum longitudinale posterius (OPLL) in Kombination mit der Verknöcherung des Ligamentum flavum (OYL) am Brustwirbel, die als eine Erkrankung der Wirbelkanal-hyperostose genannt wird, kann schwere Myelopathie verursachen, die zur Sandwich-Abdrückung des Rückenmarks von der Vorder- und Rückseite aus kommt. Für diesen Fall haben wir uns eine totale Druckentlastungstechnik des Rückenmarks und eine Spondylosynthese (spinal fusion) des Wirbelkörpers ausgedacht. Diese Operationstechnik besteht aus zwei Stufen. Die erste Stufe zielt auf die vordere und laterale Druckentlastung des Rückenmarks, die mit Entfernung des OYL nach der umfangreichen Laminektomie erreicht werden kann. Die zweite Stufe ist die vordere Entfernung des OPLL für vordere Druckentlastung, die durch die Spondylosynthese des Wirbelkörpers erreicht werden kann. Als letztes Verfahren der ersten Stufe werden zwei parallele tiefe Furchen, die bis an den Bereich des OPLL reichen, mit dem Drillbohrer von der Rückseite in den Wirbelkörper entlang den beiden Seiten des dura mater spinalis gebohrt. Diese Vorbehandlung macht die Entfernung des OPLL von stirnseitiger Richtung aus bei der zweiten Stufe noch leichter, schneller und sicherer. Diese Operation nimmt viel Zeit in Anspruch. Jedoch scheint es uns nach unseren vorliegenden Erfahrungen, daß these Operation ein vielversprechendes Verfahren sei.

     

Ossification of the posterior longitudinal and yellow ligaments on the lumbar spine

Ossification of the posterior longitudinal ligament and ossification of the yellow ligament are the main causes of spinal canal stenosis. This article describes a case of ossification of the posterior longitudinal and yellow ligaments on the lumbar spine. The patient presented with gradually worsening left lower-extremity ache and pain. The deep tendon reflex was hyperreflexia in the lower extremities. Disturbances existed in the blade and bowel. The ossified lesion of ossification of the posterior longitudinal ligament was observed at L5-S1, and plain lateral radiographs and computed tomography revealed ossification of the yellow ligament on L3, which occupied a large part of the spinal canal. Because of the findings on the preoperative radiographs, we performed posterior approach decompression and bone grafting and excisied the ossified lesion. Pedicle screws were inserted from L3 to S1. The patient's symptoms disappeared postoperatively, and his Japanese Orthopaedic Association score was 25 two weeks postoperatively. No standard surgical procedure exists for the treatment of lumbar ossification of the posterior longitudinal ligament, but it is important to select a surgical procedure according to individual patient conditions. Many factors, such as local mechanic stress, tissue metabolism, high glucose, and genetics, contribute to the progression of ossification of the posterior longitudinal and yellow ligaments on the lumbar spine. However, the mechanism is unclear. Further study and long-term follow-up on lumbar ossification of the posterior longitudinal ligament is needed.     

Ossification of posterior longitudinal ligament of the cervical spine in non-Japanese Asians

"The Japanese disease," ossification of the posterior longitudinal ligament, is not confined to the Japanese only. A similar incidence of 0.8% was found in this study among non-Japanese Asians. Of 5167 patients who attended the Mount Elizabeth Hospital in Singapore for cervical spine complaints, 43 patients were found to have ossification of the posterior longitudinal ligament, forming the largest non-Japanese series. All but one patient were of Mongolian origin, and males were affected four times more commonly than females. Diabetes mellitus was present in 16%. There was a significant association between ossification of the posterior longitudinal ligament and calcification of other cervical paraspinal ligaments. It is suggested that a generalized tendency to calcification may be an important etiological factor in ossification of the posterior longitudinal ligament. Four of the patients required surgery, and in our experience, anterior spinal fusion with removal of the ossified ligament or multilevel laminoplasty gives satisfactory results.     

Postoperative cerebrospinal-fluid fistula associated with erosion of the dura. Findings after anterior resection of ossification of the posterior longitudinal ligament in the cervical spine.

Of twenty-two patients who had had anterior decompression of the spinal canal for ossification of the posterior longitudinal ligament and cervical myelopathy, seven had absence of the dura adjacent to the ossified part of the ligament. The spinal cord and nerve-roots were visible through this defect. Although the arachnoid membrane appeared to be intact and watertight in most patients, a cerebrospinal-fluid fistula developed postoperatively in five, and three had a second operation to repair the defect in the dura. On the basis of this experience, we recommend use of autogenous muscle or fascial dural patches, immediate lumbar subarachnoid shunting, and modification of the usual postoperative regimen, such as limitation of mechanical pulmonary ventilation to the shortest time that is safely possible and use of anti-emetic and antitussive medications to protect the remaining coverings of the spinal cord when the dura is found to be absent adjacent to an ossified portion of the posterior longitudinal ligament in the cervical spine.     

Orthotopic ossification of the spinal ligaments of zucker fatty rats: A possible animal model for ossification of the human posterior longitudinal ligament

Ossification of the posterior longitudinal ligament is a human genetic disease in which pathological ectopic ossification of the spinal ligaments develops. This leads to myelopathy or radiculopathy due to compression of the spinal cord. In this study, we investigated the histological features of orthotopic ossification of the spinal ligaments of senile Zucker fatty rats. A remarkably high incidence of orthotopic ossification was observed mainly in the thoracic spinal ligaments as compared with controls. The histopathological findings were similar to those for ossification of the human posterior longitudinal ligament. Bone morphogenetic proteins and activins, which exert their effects by way of specific type-I and type-II serine/threonine kinase receptors, play important roles in the formation of bone and cartilage. In the spinal ligaments of Zucker fatty rats, bone morphogenetic protein receptors and activin receptors were immunohistochemically detected around the ossified foci in a manner similar to that previously shown for the ossified tissue from patients who had ossification of the posterior longitudinal ligament. Thus, bone morphogenetic proteins and activin receptors might play important roles in orthotopic ossification of the spinal ligaments of Zucker fatty rats as well as in ossification of the posterior longitudinal ligament of humans. In addition, bone morphogenetic protein-receptor-IA was expressed in the nonossified ligament, suggesting that the spinal ligaments of the rats may have a predisposition to orthotopic ossification. In the controls, no expression of bone morphogenetic protein receptors or of activin receptors was observed. In conclusion, there is a great degree of similarity between orthotopic ossification of the spinal ligaments of Zucker fatty rats and ossification of the posterior longitudinal ligament of humans. Thus, the rats provide a useful animal model for the study of ossification of the human posterior longitudinal ligament.     

后纵韧带钩辅助下颈椎后纵韧带骨化物切除减压术

目的探讨后纵韧带钩辅助下颈椎后纵韧带骨化物前路切除的适应证、方法及其临床效果。方法患者19例,男14例,女5例;年龄51-71岁,平均59岁。术前影像学检查结果示后纵韧带骨化物局限型6例,分节型13例;椎管狭窄率32％-75％,平均54％。术前神经功能JOA评分4-14分,平均9．6分。行颈前路常规手术入路,椎体开槽切骨达椎体后壁,范围超过后纵韧带骨化灶。利用后纵韧带钩插入后纵韧带下,钩起后纵韧带及骨化物,在后纵韧带与硬膜间形成一间隙,直视下用超薄型枪状咬骨钳切除后纵韧带及骨化物,而后植骨固定,恢复颈椎稳定性。结果随访6-36个月,平均16个月。术后JOA评分8～16分,平均12．8分,恢复率42％＇-92％,其中疗效优9例,良7例,可3例,优良率84．2％。4例患者术后并发脑脊液漏,保守治疗后均获得痊愈。术后CT和MR检查显示骨化后纵韧带切除完全,脊髓和硬膜囊形态恢复良好。结论后纵韧带钩可提高颈椎前路手术切除后纵韧带骨化物的安全性和有效性,适用于局限型和分节型、切除范围在两个椎节之间的颈椎后纵韧带骨化症患者。     

Experimental study on ossification of spinal ligaments in the rabbit under influence of bone morphogenetic protein

Bone morphogenetic protein (BMP) is known to induce cartilage from mesenchymal cells in organ culture. The purpose of the present study was to determine whether spinal ligaments differentiate into cartilage when cultured with BMP. Implantation of BMP into the yellow ligament was also done to make a model of the ossification of yellow ligament. The rabbit was employed as an experimental animal. In organ culture, BMP induced new cartilage from the posterior longitudinal ligament, the yellow ligament and the supraspinous ligament. This indicates that spinal ligaments have the potential to ossify, and bone or periosteum may not have a direct relationship with spinal ligament ossification. Ossification of the yellow ligament was produced by implantation of BMP. Blood vessels are thought to have some role in the ossification of spinal ligaments. The spinal cord was compressed posteriorly by the ossified yellow ligament. This ossification of the yellow ligament resembled that of human beings and may be regarded as a useful experimental model.     

Long-term results of the anterior floating method for cervical myelopathy caused by ossification of the posterior longitudinal ligament

STUDY DESIGN: Results of the anterior floating method used to decompress ossification of the posterior longitudinal ligament were studied for an average postoperative interval of 13 years. OBJECTIVE: To investigate the long-term results of the anterior floating method used to manage ossification of the posterior longitudinal ligament. SUMMARY OF BACKGROUND DATA: The anterior floating method is a technique that differs from the extirpation method used to manage ossification of the posterior longitudinal ligament. Reports of the long-term results from anterior decompression used to manage cervical ossification of the posterior longitudinal ligament are rare. METHODS: The anterior floating method was used to decompress cervical ossification of the posterior longitudinal ligament in 63 patients. These patients were followed for more than 10 years with neurologic evaluations using a scoring system proposed by the Japanese Orthopedic Association (JOA score). RESULTS: The recovery rate was 66.5% at 10 years and 59.3% at 13 years, the time of the final survey. Operative outcomes most closely reflected the preoperative duration and severity of myelopathy (JOA score) and the preoperative cross-sectional area of the spinal cord. There was no correlation with the canal narrowing ratio or the thickness of ossification of the posterior longitudinal ligament. Delayed deterioration was attributed to an original inadequate decompression and progression of ossification of the posterior longitudinal ligament outside the original operative field. There was no evidence of significant recurrent ossification of the posterior longitudinal ligament within the margins of prior decompression. CONCLUSIONS: The anterior floating method appears to yield adequate long-term outcomes when used to manage ossification of the posterior longitudinal ligament.     

Surgical management of cervical cord injury with ossification of the cervical posterior longitudinal ligament

Objective: To identify an appropriate surgical approach for the management of cervical cord injury with ossification of the posterior longitudinal ligament. Methods: A retrospective study of 25 cases of cervical cord injury with ossification of the posterior longitudinal ligament was performed. Two cases were classified as Frankel grade A, three as grade B, fourteen as grade C, and six as grade D. Treatment procedures consisted of anterior decompression with instrumentation (twelve patients), posterior decompression (eight patients), and combined anterior and posterior decompression (five patients). Results: There were no iatrogenic injuries of great vessels, trachea, esophagus or spinal cord. All patients were followed up for 15–86 months (average, 38.3 months). All segment with anterior fixation attained solid fusion, without implants loosening or breakage. No reclosed open‐door was found after posterior laminoplasty. Twenty‐one patients improved by one to two Frankel grades. The patients with complete spinal cord injury achieved no neurologic recovery, but did experience relief of upper limb pain or numbness. Conclusion: The surgical outcomes of cervical cord injury with ossification of the posterior longitudinal ligament were satisfactory. It is important to select a suitable surgical approach according to the findings on radiological imaging and the clinical characteristics and general condition of the patients.     

颈椎前路手术中后纵韧带切除的探讨

目的：探讨颈椎前路手术后纵韧带切除的指征、方法和注意事项，方法：对2000年4月－2002年4月后纵韧带切除的50例颈椎前路手术患者的临床资料及手术治疗结果进行回顾性分析。结果：42例获得6个月以上随访，根据JOA评分标准，平均改善率为70．5％，优14例，良16例，中9例，差3例，结论：后纵韧带退变肥厚、后纵韧带骨化或硬膜外型颈椎间盘脱出压迫颈髓时，行颈椎前路手术时应切除后纵韧带，彻底减压。     

Surgical treatment of lumbar ossification of the posterior longitudinal ligament. Report of two cases and description of surgical technique

The authors report two cases of patients with lumbar ossification of the posterior longitudinal ligament (OPLL). One patient underwent surgery via the single posterior approach, and the other patient underwent combined anterior-posterior surgery. The authors consider the anterior approach for excision of the ossified lesion to be the most reasonable for treatment of lumbar OPLL. It is extremely important, however, to select the surgical procedure according to the individual patient's condition.     

Diagnosis and surgery of ossification of posterior longitudinal ligament associated with dural ossification in the cervical spine

Direct removal of the ossified mass via anterior approach carries good decompression to ossification of the posterior longitudinal ligament (OPLL) in the cervical spine. Ossification occasionally involves not only the posterior longitudinal ligament but also the underlying dura mater, which increased the opportunity of the cerebrospinal fluid (CSF) leakage or neurological damage. The surgeon was required to recognize the dural ossification (DO) and need more cautious manipulation. Hida et al. first described the computed tomography (CT) findings that indicated the association with DO, and suggest the double-layer sign appeared more specific for DO. This study reviewed 138 patients who received anterior cervical corpectomy and fusion (ACCF) for OPLL, and 40 patients were found in the association with DO during anterior procedure. Radiological studies revealed that the patients with severe OPLL (higher occupying rate and larger extent) have increasing opportunity of association with DO. The double-layer sign, as a specific indicator for association with DO was sensitive in the patients with mild OPLL, but less frequent in those with severe OPLL with DO. Two surgical techniques were used for the patients with DO in anterior decompression procedure. When the double-layer sign was observed on CT scans, the OPLL could be separated from DO through a thin layer consisting a nonossified degenerated PLL to avoid CSF leakage. Otherwise, the entire ossified mass including OPLL and DO was removed completely. In this technique, the arachnoid membrane needed to be persevered with the aid of microscope to avoid a large area of membrane defect, resulting in uncontrolled CSF leakage. There was no significant difference in clinical results between the patients with DO and those without DO. Therefore, ACCF is meritorious for the patient with OPLL associated with DO, although more difficult manipulation and higher risk of CSF leakage.     

Hypertrophy of the posterior longitudinal ligament is a prodromal condition to ossification: a cervical myelopathy case report

STUDY DESIGN: A histopathologic examination of a specimen that showed hypertrophy of the posterior longitudinal ligament of the cervical spine. OBJECTIVES: To illustrate the possibility of hypertrophy of the posterior longitudinal ligament as a prodromal condition to ossification of the posterior longitudinal ligament. SUMMARY OF BACKGROUND DATA: Despite much study, the pathology of ossification of the posterior longitudinal ligament still remains unclear. Hypertrophic change often is seen in the part of the ossified ligament; however, there have been few histopathologic reports on hypertrophy of the posterior longitudinal ligament. Some reports have suggested that hypertrophy of the posterior longitudinal ligament is a prodrome of ossification of the posterior longitudinal ligament. METHODS: A 64-year-old man was admitted to the hospital because of gait disturbance and developed oliguria. In a plain radiograph, segmental ossification of the posterior longitudinal ligament was found at C4, C5, and C6. Computed tomograph myelogram revealed a soft tissue shadow, maximum 3.8 mm in diameter, on the dorsal side of the ossification of the posterior longitudinal ligament at C5 and C6. Magnetic resonance T1-weighted image (T1WI) showed an equivalent signal with the intervertebral disc on the dorsal side of ossification of the posterior longitudinal ligament. This lesion was enhanced with Gd-DTPA and confirmed as hypertrophy of the posterior longitudinal ligament. Cervical anterior decompression and fusion were performed using Yamaura's technique. The ossified and thickened lesion was elevated and removed en bloc. Then, hematoxylin-eosin and toluidine blue staining was performed to detect metachromasia. RESULTS: Macroscopic examination of the specimen revealed that soft tissue formation was connected with the C4-C5 intervertebral space and extended downward to C6-C7. Histopatholgically, collagen fibers were proliferating in the long-axis direction on both ventral and dorsal sides. This was surrounded by extended nucleus pulposus-like chondrocyte tissue, where endplate cartilage was detected around the C4 pedicle. Roux staining was low, and partial vascular and cellular infiltration was observed, although it was not marked. CONCLUSION: The herniated nucleus pulposus involving endplate cartilage from C4-C5 was limited to the superficial layer, and proliferation of nucleus pulposus-like chondrocytes occurred in the herniated tissue, where they might undergo a change in cell phenotype. The results of the present study support the hypothesis that hypertrophy of the posterior longitudinal ligament is a prodromal condition to ossification of the posterior longitudinal ligament.     

前路根治性减压治疗严重颈椎后纵韧带骨化症

目的 报告前路后纵韧带根治性切除治疗椎管占位率＞50%的严重颈椎后纵韧带骨化症(OPLL)的手术疗效.方法 2002年7月至2006年2月,采用前路切除骨化韧带减压术治疗椎管占位率＞50%的严重OPLL患者26例.男性18例,女性8例;年龄43～73岁,平均59岁;骨化物形态均为基底开放型.术前骨化率50%～85%,平均(65±20)%;脊髓矢状径相对值(25±7)%;JOA评分(8.7±2.8)分.采用前路减压直接切除骨化物,行钛网或自体髂骨植骨,带锁钢板固定.26例患者中,行一个椎体次全切除+单节段椎间隙减压10例,2个椎体次全切除术3例,单节段椎体次全切除13例.所有患者均行脑诱发电位(ECP)监护,CT横断面测量骨化率,MRI T2 加权测量脊髓矢状径相对值;记录患者并发症、JOA评分,计算改善率.结果 26例患者均顺利实施前路手术,随访6个月至4年(平均2年8个月).术后骨化率平均(10±5)%,脊髓矢状径相对值(75±15)%,JOA评分(14.2±2.5)分,改善率(61±24)%.3例合并糖尿病患者出现短暂神经症状恶化,其中1例行二次血肿清除术,患者神经症状均在8周内恢复;2例出现脑脊液漏(包括1例合并糖尿病者),经保守治疗2周后痊愈;无内固定失败.结论 前路手术直接减压治疗严重OPLL,神经功能恢复更彻底,但对技术要求较高.     

Image-guided surgery for thoracic ossification of the posterior longitudinal ligament. Technical note

The authors describe an anterior decompression procedure for thoracic ossification of the posterior longitudinal ligament (PLL) in which they used an image guidance system in three cases. To make registration possible in anterior thoracic surgery, they devised a surgical reference frame that could be connected to a rod and attached to an external fixation device, which was then attached to the thoracic VB. The mean fiducial error at the registration was acceptable (range 0.5-0.8 mm). They were able to confirm the success of decompression on postoperative computerized tomography scans. In the removal of an ossified thoracic PLL, an image guidance system has been shown to be a useful tool.     

颈椎后纵韧带骨化症的前路骨化灶悬切减压治疗

目的 探讨颈椎后纵韧带骨化症采取颈前路骨化灶悬切减压治疗效果.方法 颈椎后纵韧带骨化症42例136个骨化节段.颈前路椎体开槽,深至椎体后缘,与硬膜严重粘连不宜切除的骨化灶可用丝线缝穿骨化灶一侧残余的后纵韧带或骨化灶周围的纤维组织,轻轻提起系在植骨块或颈长肌上,使骨化灶完全缩入骨槽内;对体积较小、与硬膜粘连轻的骨化灶予以...     

Cervical spine stenosis due to ossification of the posterior longitudinal ligament in Italian patients: surgical treatment and outcome

Ossification of the posterior longitudinal ligament (OPLL) of the cervical spine is a frequent pathological entity in people of Japanese and Asian extraction and is reported with increasing frequency also in the USA; on the contrary, reports in the European and particularly in the Italian literature remain rare. This paper describes 8 Italian patients with cervical spine stenosis due to OPLL extending three to five vertebral segments (and above C3 in four cases). Magnetic resonance imaging shows the extent of the ossification well in terms of height and cord compression, while computed tomography is useful to measure the thickness of the bone mass and the residual spinal canal. Anterior cervical decompression by discectomy, corpectomy, and removal of the ossified ligament is the treatment of choice and results in clinical improvement in most cases. Decompressive laminectomy may be reserved for patients with ossification extending to four or five levels and above C3. The surgical technique and intraoperative findings are discussed. Received: 30 March 1998     

不同术式治疗无骨折脱位型伴后纵韧带骨化颈髓损伤的疗效分析

目的 分析不同术式治疗无骨折脱位型颈髓损伤伴后纵韧带骨化的疗效.方法 回顾性分析2000年2月至2009年1月收治的42例伴后纵韧带骨化无骨折脱位型颈髓损伤患者的临床资料,男26例,女16例;年龄49～78岁,平均60岁;受伤至就诊时间为4 h～11d,平均4 d.脊髓损伤程度按美国脊髓损伤协会(ASIA)分级:A级2例,B级8例,C级21例,D级11例.采用前路手术19例,后路手术13例,后前路联合手术10例.按照ASIA神经功能评分系统对患者术前、术后随访时的神经功能进行评分,并计算3种术式患者的感觉和运动功能改善情况.结果 所有患者均获随访,时间为13～87个月(平均34.2个月).所有患者脊髓功能获不同程度的改善,术后神经功能评分较术前均有提高,差异有统计学意义(P＜0.05).前路组、后路组及后前联合组3组术后感觉和运动功能恢复率分别为(53.12±0.94)%和(35.88±1.61)%、(40.41±2.33)%和(35.82±1.03)%、(43.97±4.74)%和(34.18±1.65)%.结论 3种术式可以不同程度地改善无骨折脱位型伴后纵韧带骨化颈髓损伤患者的脊髓功能,合理选择手术入路是取得良好疗效的关键.