Acute cervical cord injury associated with ossification of the posterior longitudinal ligament

OBJECTIVE: Patients with ossification of the posterior longitudinal ligament (OPLL) sometimes present with acute spinal cord injury caused by only minor trauma. In the present study, we reviewed our experience of acute cervical cord injury associated with OPLL to understand the pathomechanisms and to provide clinical information for management of this disorder. METHODS: Twenty-eight patients were retrospectively analyzed. There were 26 men and 2 women, aged 45 to 78 years (mean, 63.0 yr). Most patients experienced incomplete spinal cord injury (Frankel Grade A, 3; B, 1; C, 15; and D, 9). RESULTS: Radiological studies revealed continuous- or mixed-type OPLL in 14 patients and segmental-type OPLL in 14 patients. The sagittal diameter of the spinal canal was reduced to 4.1 to 10 mm at the narrowest level as a result of OPLL. Developmental size of the spinal canal was significantly smaller in the group with segmental OPLL. Magnetic resonance imaging scans revealed that spinal cord injury occurred predominantly at the caudal edge of continuous-type OPLL or at the disc levels. Surgery was performed in 24 patients either by posterior (18 patients) or anterior (6 patients) decompression at various time intervals after the trauma. Twenty patients (71%) displayed improvement in Frankel grade. CONCLUSION: The present study demonstrates the preexisting factors and pathomechanisms of acute spinal cord injury associated with cervical OPLL. Magnetic resonance imaging is useful to understand the level and mechanism of injury. Further investigation will be needed to elucidate the role of surgical decompression.     

胸椎后纵韧带骨化的临床特点及治疗策略

目的回顾研究手术治疗胸椎后纵韧带骨化症(OPLL)的临床特点及治疗方法。方法1991至2005年手术治疗胸椎OPLL55例,男19例,女36例;年龄35～73岁,平均51.9岁。均伴有脊髓损害。手术方式包括单纯椎管后壁切除术34例、前方OPLL切除减压术15例以及前后路联合手术6例。结果55例中36例(65.5%)合并胸椎黄韧带骨化(OLF),18例(32.7%)合并颈椎OPLL。单纯发生于上胸椎的OPLL13例(23.6%),中胸椎12例(21.8%),下胸椎及胸腰段17例(30.9%),广泛分布者13例(23.6%)。43例获得随访,平均随访时间47.1个月(6～168个月)。37例神经功能有改善,改善率为76.6%,无改善2例,加重4例。前方入路获随访者13例,其中3例症状加重,余改善率平均为82.9%(42.9%～100%)。后路椎管后壁切除术获随访者25例,1例无改善,1例加重,余改善率平均为72.6%(22.2%～100%)。前后路联合手术获随访5例,1例无改善,余改善率平均为83.9%。结论胸椎OPLL常合并胸椎OLF及颈椎OPLL。上胸椎OPLL合并颈椎管狭窄可一期行颈后路单开门及上胸椎椎管后壁切除术。两个节段以内的OPLL且不合并有造成脊髓压迫的胸椎OLF可行前路OPLL切除减压术,否则行后路椎管后壁切除术。单节段的OPLL合并胸椎OLF可行前后路联合手术。     

Surgical outcome of ossification of the posterior longitudinal ligament (OPLL) of the thoracic spine: implication of the type of ossification and surgical options

OBJECTIVE: Ossification of the posterior longitudinal ligament (OPLL) in the thoracic spine produces myelopathy through anterior spinal cord compression that is usually progressive and unaffected by conservative treatment. Therefore, early decompressive surgery is imperative. However, decompression surgery of thoracic myelopathy is difficult, and the outcome is often poor. A retrospective study was conducted to investigate the surgical outcome of 21 patients with thoracic OPLL to evaluate which type of surgical approach is better and which type of thoracic OPLL results in a better surgical outcome. METHODS: A total of 21 patients with thoracic OPLL (10 men and 11 women; mean age 54 years), who underwent surgical treatment at our department from March 1985 to October 2000, were included in the study. Seven patients exhibited the flat-type OPLL and underwent either anterior decompression and fusion (one patient), anterior decompression via a posterior approach (three patients), or expansive laminoplasty (three patients). Fourteen patients exhibited the beak-type OPLL and also underwent either anterior decompression and fusion (two patients), anterior decompression via a posterior approach (six patients), or expansive laminoplasty (six patients). RESULTS: Regarding of operative time and blood loss, there were no marked differences between the two types of OPLL, regardless of the type of surgical procedure; anterior decompression and fusion and anterior decompression via a posterior approach yielded longer operative times and larger blood loss volumes than expansive laminoplasty. Concerning clinical outcome, there were five cases of neurologic deterioration. All of the five deteriorated cases were of the beak-type OPLL treated by a posterior approach. Two of these patients were treated with expansive laminoplasty. CONCLUSIONS: There were five instances of neurologic deterioration in our thoracic OPLL series, and all of them exhibited beak-type OPLL. In the beak-type OPLL, a subtle alteration in the spinal alignment during posterior decompression procedures may increase spinal cord compression, leading to the deterioration of symptoms. A potential increase in kyphosis following laminectomy should be avoided by fixation with a temporary rod. If intraoperative monitoring suggests spinal cord dysfunction, an anterior decompression procedure should be attempted as soon as possible.     

Cervical ossification of the posterior longitudinal ligament: factors affecting the effect of posterior decompression

Objective: Decompression procedures for cervical myelopathy of ossification of the posterior longitudinal ligament (OPLL) are anterior decompression with fusion, laminoplasty, and posterior decompression with fusion. Preoperative and postoperative stress analyses were performed for compression from hill-shaped cervical OPLL using 3-dimensional finite element method (FEM) spinal cord models.

Methods: Three FEM models of vertebral arch, OPLL, and spinal cord were used to develop preoperative compression models of the spinal cord to which 10%, 20%, and 30% compression was applied; a posterior compression with fusion model of the posteriorly shifted vertebral arch; an advanced kyphosis model following posterior decompression with the spinal cord stretched in the kyphotic direction; and a combined model of advanced kyphosis following posterior decompression and intervertebral mobility. The combined model had discontinuity in the middle of OPLL, assuming the presence of residual intervertebral mobility at the level of maximum cord compression, and the spinal cord was mobile according to flexion of vertebral bodies by 5°, 10°, and 15°.

Results: In the preoperative compression model, intraspinal stress increased as compression increased. In the posterior decompression with fusion model, intraspinal stress decreased, but partially persisted under 30% compression. In the advanced kyphosis model, intraspinal stress increased again. As anterior compression was higher, the stress increased more. In the advanced kyphosis +?intervertebral mobility model, intraspinal stress increased more than in the only advanced kyphosis model following decompression. Intraspinal stress increased more as intervertebral mobility increased.

Conclusion: In high residual compression or instability after posterior decompression, anterior decompression with fusion or posterior decompression with instrumented fusion should be considered.     

Laser-assisted anterior cervical corpectomy versus posterior laminoplasty for cervical myelopathic patients with multilevel ossification of the posterior longitudinal ligament

OBJECTIVE: This study reports on the comparative results of a series of patients with multilevel cervical ossification of the posterior longitudinal ligament (OPLL) who were treated with laser-assisted anterior corpectomy or laminoplasty. METHODS: Forty-eight patients (21 patients with anterior corpectomy and 27 patients with laminoplasty) with cervical OPLL involvement of three or more vertebral bodies were retrospectively reviewed. Both pre- and postoperatively neurological status was graded according to the Nurick grading system. The anteroposterior (AP) diameter change at the narrowest part of the spinal canal, the change in the regional and the overall cervical Cobb's angle, and the change in cervical range of motion (ROM) were all measured. The mean follow-up periods were 21.8 mo and 29.1 mo for the corpectomy and laminoplasty patients, respectively. RESULTS: The mean changes in the pre- to postoperative Nurick grades were 1.9 for the corpectomy group and 1 for the laminoplasty group (p < 0.05). The mean changes in the pre- to postoperative spinal canal AP diameters were 9.1 mm and 4.11 mm, respectively, for the corpectomy group and the laminoplasty group (p < 0.05). The mean changes of the regional Cobb's angle were 1.7 degrees and -3.1 degrees (p = 0.06), and the mean changes of the overall cervical Cobb's angle were 1.1 degrees and -1.6 degrees , respectively, for the corpectomy group and the laminoplasty group (p > 0.05). The changes in the cervical degree of ROM were -19.6 degrees and -19.7 degrees , respectively, for the corpectomy group and the laminoplasty group (p > 0.05). CONCLUSIONS: Direct decompression of the spinal cord by laser-assisted anterior cervical corpectomy was shown to be a better surgical option on long-term follow-up, yielding more recovery of neurological deficits, achieving adequate decompression of the spinal canal, and preventing the development of regional kyphosis at the operated level of the spine, in patients with multilevel cervical OPLL.     

Staged spinal cord decompression through posterior approach for thoracic myelopathy caused by ossification of posterior longitudinal ligament.

STUDY DESIGN: Prospective clinical study of the effect of staged elimination of anatomic factors inhibiting posterior shift of the thoracic spinal cord on the degree of posterior shift of the thoracic spinal cord and its significance in augmenting the safety of ossification of posterior longitudinal ligament (OPLL) manipulation in thoracic OPLL myelopathy. OBJECTIVES: To develop a comprehensive method that enables safe and sufficient decompression of the spinal cord for thoracic OPLL myelopathy. SUMMARY OF BACKGROUND DATA: Decompression of the spinal cord by direct manipulations of thoracic OPLLs, via either anterior or posterior approach, caused some iatrogenic catastrophic spinal cord injuries, and methods to prevent such injuries during surgery have not yet been developed. METHODS: Procedures of elimination of anatomic factors inhibiting posterior shift of the thoracic spinal cord were performed in stages at intervals of between 1 month and 11 years depending on patients' neurologic status. The first stage operation consisted of extensive cervicothoracic laminoplastic decompression with or without posterior longitudinal durotomy, and if the decompression were insufficient, measures for OPLL-spinal cord separation with or without OPLL manipulation were added. RESULTS: All 17 patients with thoracic OPLL myelopathy showed improvements of neurology comparable with those with successful anterior approaches after decompression. The mean follow-up period was 42 months (range 6-101 months). Neurologic improvements persisted for the entire follow-up period in all patients except one patient who developed arachnoid cyst compressing the dorsum of the once-decompressed spinal cord 30 months after surgery. CONCLUSIONS: Staged posterior decompression to eliminate anatomic factors inhibiting posterior shift of the thoracic spinal cord is the safest and the most reliable method of spinal cord decompression to treat thoracic OPLL myelopathy, so far. However, long-term results are required before the methods can be established.     

颈椎病伴椎管狭窄患者再手术问题探讨

目的：探讨颈椎病伴椎管狭窄患者再手术的原因、手术方式及其相关问题。方法：我院2002年7月～2003年12月对40例颈椎病伴椎管狭窄术后疗效不佳或症状复发的患者进行了后路多节段（5个或以上）减压手术。根据其手术治疗方式及影像学资料分析再手术原因，并进行术后疗效评价。结果：经前路手术者再手术的主要原因为：（1）伴有多节段颈椎管狭窄因素时，只选择部分压迫重的节段行减压融合15例；（2）经前路多节段（≥3个节段）减压融合后，相邻节段继续退变，出现新的脊髓压迫表现及椎间不稳定9例；（3）伴有OPLL时，行部分节段前路减压融合后，病变呈进展表现，产生或加重对脊髓的压迫8例。经后路手术者再手术的原因为：（1）后路减压节段不够5例（包括1例前后路联合手术者）；（2）后路减压不充分3例。再手术后随访1．3～2．7年，平均2．1年，所有患者脊髓功能获得一定的提高，JOA评分改善率为51．3％。结论：颈椎病伴椎管狭窄病例再手术的主要原因为椎管狭窄因素仍然存在，经后路多节段（5个或以上）减压手术治疗可彻底去除颈椎管狭窄因素，有效解除脊髓前、后方所受的压迫，可获得较满意的临床疗效。     

Choice of surgical approach for ossification of the posterior longitudinal ligament in combination with cervical disc hernia

Ossification of the posterior longitudinal ligament (OPLL) is a common spinal disorder that presents with or without cervical myelopathy. Furthermore, there is evidence suggesting that OPLL often coexists with cervical disc hernia (CDH), and that the latter is the more important compression factor. To raise the awareness of CDH in OPLL for spinal surgeons, we performed a retrospective study on 142 patients with radiologically proven OPLL who had received surgery between January 2004 and January 2008 in our hospital. Plain radiograph, three-dimensional computed tomography construction (3D CT), and magnetic resonance imaging (MRI) of the cervical spine were all performed. Twenty-six patients with obvious CDH (15 of segmental-type, nine of mixed-type, two of continuous-type) were selected via clinical and radiographic features, and intraoperative findings. By MRI, the most commonly involved level was C5/6, followed by C3/4, C4/5, and C6/7. The areas of greatest spinal cord compression were at the disc levels because of herniated cervical discs. Eight patients were decompressed via anterior cervical discectomy and fusion (ACDF), 13 patients via anterior cervical corpectomy and fusion (ACCF), and five patients via ACDF combined with posterior laminectomy and fusion. The outcomes were all favorable. In conclusion, surgeons should consider the potential for CDH when performing spinal cord decompression and deciding the surgical approach in patients presenting with OPLL.     

Spinal cord injury in cervical spinal stenosis by minor trauma

BackgroundThe size of the spinal canal is a factor that contributes to the neurologic deficits associated with cervical OPLL and CSM. We investigate the development of neurologic deterioration after minor trauma and the clinical results of decompressive surgery in cervical spinal stenosis retrospectively.MethodWe treated 200 cases (98 cervical OPLLs and 102 CSMs) of cervical spinal stenosis for 8 years. There were 63 (33.5%) minor trauma cases to the cervical spine in 200 patients. Of these 63 patients, 18 developed myelopathy, 13 showed deterioration of preexisting myelopathy, and no neurologic change was observed in 32 patients. The neurologic status was assessed by the JOA score. The patients were divided into 2 groups according to the residual cervical spinal canal diameter: group I (<10 mm cervical spinal canal) and group II (≥10 mm cervical spinal canal).ResultsNeurologic outcome depended on the diameter of the residual spinal canal; 22 of the 25 patients in group I developed neurologic deterioration, whereas that occurred in 8 of the 38 patients in group II (P < .05). After surgical decompression, 8 patients in group I and 30 patients in group II came out with an improved JOA score of more than 50% (P < .05).ConclusionEven indirect minor trauma to the neck can cause irreversible changes in the spinal cord if there is marked stenosis of the cervical spinal canal. It may be beneficial to check lateral radiograph of the cervical spine as a screening tool for early detection of cervical spinal stenosis especially in Asian people older than 40 years.     

压迫性颈脊髓病再手术原因分析

目的：探讨压迫性颈脊髓病再手术的原因。方法：回顾性分析308例压迫性颈脊髓病再手术患者的临床及影像学资料。结果：颈前路术后再手术的原因有：合并发育性颈椎管狭窄115例;合并颈椎后纵韧带骨化30例;上、下节段间盘再突出25例;脊髓减压不充分24例;“跳跃式”间盘切除10例。颈后路术后冉手术的原因有：减压范围不足77例;开门上、下节段压迫脊髓14例;前方椎间盘仍压迫脊髓9例：单开门术后再关门4例。结论：手术前充分分析颈脊髓受压的病理因素,合理选择术式、改善手术技术是减少压迫性颈脊髓病冉手术率的重要措施。     

Posttraumatic atlanto-axial subluxation and myelopathy. Efficacy of anterior decompression

Compression of the neuraxis may occur after displaced fractures of the dens. Nonunion or malunion increases the risk of developing neurologic complications because of the resulting atlanto-axial instability. Posterior decompression has generally been the surgical solution to myelopathy at this level. Two patients with cervical myelopathy due to displaced ununited dens fractures were treated with posterior fossa decompression and high cervical laminectomy. Both patients deteriorated after the surgery. Most of their neurologic deficits finally resolved after microsurgical transoral decompression (by resection of the dens). In those patients in whom atlanto-axial instability causes primarily anterior compression of the neuraxis, especially by a bony lesion, decompression posteriorly may not achieve the desired effect, and, instead, may cause a deterioration in the patient's condition. Anterior atlanto-axial subluxation effectively lengthens the bony spinal canal, which results in stretching of the relatively inelastic spinal cord over the bony deformity. If indirect methods of reduction fail to relieve the condition, then anterior transoral decompression is recommended.     

Posterior approaches in the management of cervical spondylosis and ossification of the posterior longitudinal ligament

BACKGROUND: If the cervical lordotic curvature has been well preserved, spondylostenosis or ossification of the posterior longitudinal ligament, with or without instability, may be approached posteriorly in selected older patients (over 65 years of age). Posterior surgical alternatives include the laminectomy with or without fusion, or laminoplasty. However, in younger patients or in geriatric patients with predominantly anterior disease with kyphosis, direct anterior surgical procedures yield better results. METHODS: Laminectomy with medial facetectomy and foraminotomy is classically performed in cases in which stability is preserved. However, posterior stabilization using either facet wiring or lateral mass fusion may be warranted. Although some consider the "open door" laminoplasty a reasonable alternative for dorsal decompression, limitations include restricted access to the hinged side, a potential for "closing of the door," and it does not offer a "real" fusion. RESULTS: Postoperative neurologic improvement may approximate an 85% incidence of good to excellent results. However, where a posterior decompression has been chosen, particularly in younger individuals with or without a lordotic curvature, or in older patients with kyphosis, they will fail to significantly improve, and will be susceptible to early neurologic deterioration. CONCLUSIONS: Posterior approaches to cervical disease may be successful in geriatric individuals in whom the cervical lordotic curvature has been well preserved. However, it is inappropriate for either older or younger patients with predominantly anterior disease, for whom direct anterior decompression with or without posterior stabilization is indicated. In those patients with significant ventral ossification of the posterior longitudinal ligament (OPLL), direct anterior resection will result in improved neurologic outcomes, whereas posterior decompression will fail to achieve a similar degree of neurologic recovery. Furthermore, dorsal decompression of OPLL may promote a more rapid progression of OPLL growth and concomitant neurologic deterioration.     

无脊髓压迫症状颈椎后纵韧带骨化患者的影像学特点及临床意义

目的:探讨无脊髓压迫症状颈椎后纵韧带骨化(OPLL)患者的影像学特点及临床意义。方法:分析42例无脊髓压迫症状颈椎OPLL患者初次就诊的影像学资料,男25例,女17例,年龄40～78岁,平均57岁。根据影像学表现对OPLL进行分型,观察椎管最大受压处骨化物占位率(OPLL占位率)与椎管最大受压节段活动范围(ROM)的相关性,同时观察MRI T2像上脊髓内信号的变化并随访患者症状进展情况。结果:根据Tsuyama分型标准,本组连续型24例,混合型10例,节段型8例。OPLL占位率20%～64%,平均38.4%;最大受压节段ROM平均4.5°。线性回归显示OPLL椎管占位率与ROM呈负相关(P<0.01)。所有患者未出现MRI T2相脊髓内信号改变。随访2年～5年6个月,平均3年8个月,所有患者末次随访查体均未发现脊髓压迫症临床表现。结论:无脊髓压迫症状的颈椎OPLL,以连续型骨化多见,椎管最大受压节段活动范围较小可能是其无脊髓压迫症状的原因之一。     

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.     

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.     

Ossification of the posterior cervical longitudinal ligament

Summary Forty patients with cervical myelopathy due to OPLL (Ossification of the Posterior Longitudinal Ligament) of the cervical spine were studied. According to Abe's or Yamamoto's classification, 12 of them had a 50% decrease in the cross-sectional area of the spinal canal. Subtotal vertebrectomy was carried out in 8 of these patients and the remaining 4 patients received posterior decompression. We concluded that anterior decompression, if possible, is the treatment of choice and posterior decompression is recommended only for the longitudinal type involving more than 3 segments.     

Modified ACDF Technique for the Treatment of Centrum Focal Ossification of the Posterior Longitudinal Ligament: A Case Report

Background

Anterior cervical discectomy fusion (ACDF) is a surgical procedure used to treat cervical spondylosis with anterior spinal cord compression. However, there are limitations to traditional ACDF and posterior indirect decompression when the anterior source lesion is in the center of the cervical vertebra.

Case Presentation

On June 8, 2022, our department treated a patient with cervical spondylotic myelopathy—whose high posterior longitudinal ligament (OPLL) occupied the central position of the vertebral body—with modified ACDF. The preoperative surgical plan was designed based on the relevant imaging data and assay index. Also, the visual analogue scale (VAS), Japanese Orthopaedic Association (JOA) scores, and imaging parameters of neck pain were recorded and compared. Postoperative imaging data showed that cervical curvature was recovered and spinal canal compression was relieved. The VAS score for neck pain decreased from 7 preoperatively to 1.5 at the last follow-up, while the JOA score increased from 10 preoperatively to 29 at the last follow-up. The volume of the spinal canal was restored. Simultaneously, the patient's extremity muscle strength improved and muscle tension decreased.

Conclusions

Modified ACDF may be an effective surgical method for resolving spinal cord compression in a specific location when bone mineral density is good. We can effectively avoid iatrogenic nerve injury and symptom recurrence by removing the vertebral body and the lesion directly.     

前路椎体骨化物复合体可控前移技术治疗颈椎后纵韧带骨化症的脊髓原位减压效果

目的:观察颈椎前路椎体骨化物复合体可控前移(anterior controllable antedisplacement fusion,ACAF)技术治疗颈椎后纵韧带骨化症(ossification of the posterior longitudinal ligament,OPLL)的脊髓原位减压效果。方法:回顾分析2017年6月~2018年12月我院收治的78例OPLL患者的人口学信息、影像资料以及术后指标(年龄、性别、症状持续时间、椎管侵占率和骨化累及椎体数量)。其中采用ACAF治疗42例,单开门椎管扩大椎板成形术(简称单开门椎板成形术open-door laminoplasty,LAM)治疗36例,平均随访时间21.7±4.0(12~30)个月。比较两组患者术前及末次随访时的JOA评分、脊髓面积、Cobb角、Kang′s分级以及C5神经麻痹、脑脊液漏、吞咽困难等并发症情况。结果:末次随访时,ACAF组与LAM组相比,在JOA评分(14.17±0.81分vs 13.81±1.12分,P<0.05)、脊髓面积(74.12±4.48mm^2 vs 70.36±5.60mm^2,P<0.05)、Cobb角(20.07°±1.28°vs 9.99°±0.65°,P<0.05)和Kang′s分级(0.93±1.40 vs 2.00±0.89,P<0.05)方面具有优势。对比ACAF组与LAM组的术后并发症,两组间C5神经麻痹(4.8%vs 11.1%)、脑脊液漏(2.4%vs 2.8%)、吞咽困难(9.5%vs 0%)无统计学差异。ACAF组2例出现C5神经麻痹的患者未能顺利完成原位减压。结论:ACAF手术可通过恢复椎管容积和形态实现脊髓原位减压,减压效果良好。在恢复颈椎曲度和脊髓位置形态方面,ACAF较LAM为优。     

A novel anterior decompression technique (vertebral body sliding osteotomy) for ossification of posterior longitudinal ligament of the cervical spine

Background Context

Conventional anterior decompression surgery for cervical myelopathy, including anterior corpectomy and fusion, is technically demanding and is known to be associated with a higher incidence of surgery-related complications, including cerebrospinal fluid (CSF) leakage, neurologic deterioration, and graft failure compared with posterior surgery.

Ossification of the posterior longitudinal spinal ligament--comparative studies with computerized tomography (author's transl)]

Ossification of the posterior longitudinal spinal ligament (OPLL) was characterized by calcified longitudinal band along the posterior margin of vertebrae, but it has not been possible to know how the cord is compressed within the narrowed spinal canal. Our neuroradiological studies based on CT-view of the 15 cases of OPLL suffering from various degree of myelopathy revealed: 1) Computed tomography precisely delineated shape of OPLL, which was quite polymorphic, like mushroom, irregular cubic and round. OPLL ranged more than two vertebrae was not uniform, but exhibited different configuration at each level. 2) OPLL at lower cervical and higher thoracic regions was difficult to diagnose by conventional lateral roentgenograms, but CT-scan demonstrated clearly whole extent of OPLL. 3) obliteration ratio of the affected spinal canal was calculated on CT-scan. Cases showing severe myelopathy, such as quadriparesis and neurogenic bladder, presented spinal canal stenosis of more than 30%. Spondylosis were concomittant roentgenographic findings on 13 cases of OPLL (87%). However, spondylotic changes responsible to the myelopathy were seen on only three cases. In these case, the obliteration ratio by ossificated ligament was lower than 26%. On conclusion, computed tomographic views of OPLL gave us more detailed information about the stenotic spinal canal and found to be essential examination when considering operative intervention.