Radiological manifestations and surgical outcome of combined upper cervical cord compression and cervical ossification of the posterior longitudinal ligament with a minimum 2-year follow-up

Combined upper cervical cord compression associated with cervical ossification of the posterior longitudinal ligament (OPLL) is a rare and under-recognized disorder. The aim of this study was to investigate the radiological manifestations and surgical outcome of this combined disease.Between May 2011 and July 2015, patients who underwent surgery for combined upper cervical cord compression and cervical OPLL in our institution were included in this study. After a minimum 2-year follow-up, radiological and clinical data were collected. The etiology of upper cervical cord compression and radiological features of cervical OPLL was determined. Surgical outcome was evaluated with Visual Analogue Scale (VAS), Japanese Orthopedic Association score (JOA), space available for the spinal cord (SAC) at the cephalad adjacent level, occupying ratio of OPLL and cervical lordosis.In total, 24 patients (11 men and 13 women) with a mean age of 57.9 years old were included. The etiology of upper cervical cord compression included craniovertebral junction deformity (n = 10), atlantoaxial subluxation (n = 5), and OPLL extending to C2 level (n = 9). The extent, type, and thickest level of cervical OPLL varied among the patients. Significant improvement of VAS and JOA score was noted postoperatively and at a minimum 2-year follow-up. The result was satisfactory in SAC at the cephalad level and occupying ratio of OPLL. There were no significant differences in C2/C7 lordotic angle at the preoperative, postoperative and the last follow-up examination.In conclusion, the radiological manifestations of combined upper cervical cord compression and cervical OPLL varied among the patients. Satisfied results can be achieved with adequate surgical treatment a minimum 2-year follow-up.

Clinical outcome of laminoplasty for cervical ossification of the posterior longitudinal ligament with K-line (-) in the neck neutral position but K-line (+) in the neck extension position: A retrospective observational study

Patients with cervical ossification of the posterior longitudinal ligament (OPLL) who are K-line (-) are thought to have poor clinical outcomes after laminoplasty. The aim of this study is to compare the clinical results of patients with OPLL who were K-line (-) in the neck neutral position but K-line (+) in the neck extension position (NEP group) with patients with OPLL who were K-line (+) in the neck neutral position (NNP group).Retrospectively, 42 patients who underwent cervical laminoplasty for OPLL by our surgical group during 2012 and 2013 were reviewed and were followed for at least 2 years. The patients were divided into 2 groups according to K-line status. Standing plain radiographs of the cervical spine were obtained pre- and postoperatively. Cervical spine alignment parameters included the C2-7 Cobb angle and range of motion (ROM) measured on lateral radiographs. Clinical evaluation included pre- and postoperative JOA, NDI, and VAS scores.Ten patients were classified in the NEP group, and 32 patients were classified in the NNP group. Preoperatively, the OPLL involved segments were 4.10 ± 1.66 in the NEP group and 2.53 ± 1.16 in the NNP group (P = .005). The canal-occupying ratios were 58.40 ± 11.11% in the NEP group and 29.08 ± 11.38% in the NNP group (P < .001). The mean Cobb angle of both the groups had not changed significantly at the last follow-up. The mean cervical ROM of both the groups had decreased at the last follow-up. The mean JOA score of the NEP group improved significantly from 9.70 ± 2.16 to 12.50 ± 2.27 (P = .014). The mean JOA score of the NNP group improved significantly from 11.91 ± 1.69 to 14.93 ± 1.58 (P < .001). The mean JOA recovery rate was 32.71 ± 40.45% in the NEP group and 59.00 ± 33.80% in the NNP group (P = .036). The NDI scores of both groups were significantly decreased, and the VAS scores of both groups had not changed significantly at the last follow-up.Laminoplasty is a relatively effective and safe procedure for patients with K-line (-) in the neck neutral position but K-line (+) in the neck extension position. Instead of anterior surgery, we recommend laminoplasty for those patients with OPLL extending to 3 or more segments.

Intervertebral disc calcification with ossification of the posterior longitudinal ligament

A 6-year-old girl presented to hospital with a 4 day history of increasing neck pain. White blood cell count was normal with slightly raised C-reactive protein. The patient had a limited range of neck movement, and experienced enhanced pain with neck extension. X-ray and cervical computed tomography (CT) confirmed the diagnosis of cervical intervertebral disc calcification (IDC) and IDC with ossification of the posterior longitudinal ligament (OPLL), respectively. The symptoms improved after approximately 1 week following rest and oral acetaminophen. X-ray 6 months after onset confirmed the disappearance of the calcification. IDC is often reported in children, but IDC with OPLL is extremely rare and has not been previously reported in Japan. We believe that IDC with or without OPLL in children has a good prognosis when treated conservatively.

Outcomes following Laminoplasty or Laminectomy and Fusion in Patients with Myelopathy Caused by Ossification of the Posterior Longitudinal Ligament: A Systematic Review

Study Design Systematic review. Objective To compare laminoplasty versus laminectomy and fusion in patients with cervical myelopathy caused by OPLL. Methods A systematic review was conducted using PubMed/Medline, Cochrane database, and Google scholar of articles. Only comparative studies in humans were included. Studies involving cervical trauma/fracture, infection, and tumor were excluded. Results Of 157 citations initially analyzed, 4 studies ultimately met our inclusion criteria: one class of evidence (CoE) II prospective cohort study and three CoE III retrospective cohort studies. The prospective cohort study found no significant difference between laminoplasty and laminectomy and fusion in the recovery rate from myelopathy. One CoE III retrospective cohort study reported a significantly higher recovery rate following laminoplasty. Another CoE III retrospective cohort study reported a significantly higher recovery rate in the laminectomy and fusion group. One CoE II prospective cohort study and one CoE III retrospective cohort study found no significant difference in pain improvement between patients treated with laminoplasty versus patients treated with laminectomy and fusion. All four studies reported a higher incidence of C5 palsy following laminectomy and fusion than laminoplasty. One CoE II prospective cohort and one CoE III retrospective cohort reported that there was no significant difference in axial neck pain between the two procedures. One CoE III retrospective cohort study suggested that there was no significant difference between groups in OPLL progression. Conclusion Data from four comparative studies was not sufficient to support the superiority of laminoplasty or laminectomy and fusion in treating cervical myelopathy caused by OPLL.

Long-term outcomes and prognostic analysis of modified open-door laminoplasty with lateral mass screw fusion in treatment of cervical spondylotic myelopathy

OBJECTIVES

The purpose of the present study was to explore and analyze the long-term outcomes and factors that affect the prognosis of expansive open-door laminoplasty with lateral mass screw fusion in treatment of cervical spondylotic myelopathy (CSM).

METHODS

We retrospectively reviewed 49 patients with multilevel CSM who had undergone expansive open-door laminoplasty with lateral mass screws fixation and fusion in our hospital between February 2008 and February 2012. The average follow-up period was 4.6 years. The clinical data of patients, including age, sex, operation records, pre- and postoperation Japanese Orthopedic Association (JOA) scores, cervical spine canal stenosis, and cervical curvature, were collected. Increased signal intensity (ISI) on T2-weighted magnetic resonance imaging and ossification of the posterior longitudinal ligament were also observed. Paired t-test was used to analyze the treatment effectiveness and recovery of neuronal function. The prognostic factors were analyzed with multivariable linear regression model.

RESULTS

Forty-nine patients with CSM with a mean age of 59.44 years were enrolled in this study. The average of preoperative JOA score was 9.14±2.25, and postoperative JOA score was 15.31±1.73. There was significant difference between the pre- and postoperative JOA scores. The clinical improvement rate was 80.27%. On follow-up, five patients had complaints of neck and shoulder pain, but no evidence of C5 nerve palsy was found. Developmental cervical spine canal stenosis was present in all patients before surgery. Before surgery, ISI was observed in eight patients, while ossification of the posterior longitudinal ligament was found in 12 patients. The average of preoperative cervical curvature was 21.27°±8.37° and postoperative cervical curvature was 20.09°±1.29°, and there was no significant difference between the pre- and postoperative cervical curvatures. Multivariable linear regression analysis results showed that the postoperation JOA scores were significantly affected by age, preoperative JOA scores, and preoperative ISI. Except one case of epidural hematoma, there were no complications associated with the surgery.

CONCLUSION

Treatment of CSM with posterior open-door laminoplasty with lateral mass screw fusion is effective with few complications. In addition, the normal cervical lordosis was well maintained. Age, preoperative JOA scores, and preoperative ISI were the independent factors that significantly affect disease prognosis and surgical outcomes.

Comparison of anterior decompression and fusion versus laminoplasty in the treatment of multilevel cervical ossification of the posterior longitudinal ligament: a systematic review and meta-analysis

Purpose

A meta-analysis was conducted to evaluate the clinical outcomes, complications, reoperation rates, and late neurological deterioration between anterior decompression and fusion (ADF) and laminoplasty (LAMP) in the treatment of multilevel cervical ossification of the posterior longitudinal ligament (OPLL).

Methods

All related studies published up to August 2015 were acquired by searching PubMed and EMBASE. Exclusion criteria were case reports, revision surgeries, combined anterior and posterior surgeries, the other posterior approaches including laminectomy or laminectomy and instrumented fusion, non-English studies, and studies with quality assessment scores of <7. The main end points including Japanese Orthopedic Association (JOA) score, recovery rate of JOA, cervical lordosis, complication rate, reoperation rate, and late neurological deterioration were analyzed. All available data was analyzed using RevMan 5.2.0 and Stata 12.0.

Results

A total of seven studies were included in the meta-analysis. The mean surgical level of ADF was 3.1, and the mean preoperative occupation ratios of ADF and LAMP group were 55.9% and 51.9%, respectively. No statistical difference was observed with regard to preoperative occupation ratio and preoperative JOA score. Although LAMP group had a higher preoperative cervical lordosis than ADF group (P<0.05, weighted mean difference [WMD] =−5.73, 95% confidence interval [CI] =−9.67–−1.80), significantly decreased cervical lordosis was observed in LAMP group after operation. ADF group had higher postoperative JOA score (P<0.05, WMD =2.18, 95% CI =0.98–3.38) and neurological recovery rate (P<0.05, WMD =27.22, 95% CI =15.20–39.23). Furthermore, ADF group had a lower late neurological deterioration rate than the LAMP group (P<0.05, risk difference =0.16, 95% CI =0.04–0.73). The complication rates of both groups had no statistical difference. However, LAMP group had a significantly lower reoperation rate than ADF group. The reoperation rate of ADF group (20.5%) was almost six times that of LAMP group (3.5%).

Conclusion

Our meta-analysis suggested that ADF was associated with better postoperative neurological function, neurological recovery rate, and less late neurological deterioration than LAMP in the treatment of multilevel cervical OPLL with a high mean occupation ratio. LAMP was associated with a decreased postoperative cervical lordosis, which might be a cause of late neurological deterioration. The complication rates of both groups showed no statistical difference. However, the reoperation rate was significantly higher in ADF group compared with LAMP group. Benefits and risks should be balanced when ADF or LAMP is selected.

Ossification of the Posterior Longitudinal Ligament: Etiology, Diagnosis, and Outcomes of Nonoperative and Operative Management

Study Design Narrative review. Objective To provide an overview on the diagnosis, natural history, and nonoperative and operative management of ossification of the posterior longitudinal ligament (OPLL). OPLL is a multifactorial condition caused by ectopic hyperostosis and calcification of the posterior longitudinal ligament. Familial inheritance and genetic factors have been implicated in the etiology of OPLL. The cervical spine is most commonly affected followed by the thoracic spine. The clinical manifestations range from asymptomatic to myelopathy or myeloradiculopathy. Methods Using PubMed, studies published prior to October 2014 with the keywords "OPLL, etiology"; "OPLL, genetics"; "OPLL, spinal cord injury"; "OPLL, natural history"; "OPLL, non-surgical management"; OPLL, surgical management"; "OPLL, surgical complications" were evaluated. Results The review addresses the etiology, epidemiology, classification, clinical presentation, imaging findings, and nonoperative and operative management of OPLL. Complications associated with surgical management of OPLL are also discussed. Conclusions OPLL commonly presents with myelopathy and radiculopathy. Spine providers should consider OPLL in their differential diagnosis and when reviewing images. If surgical intervention is pursued, imaging-based measurements and findings can help in choosing an anterior versus posterior surgical approach.

Central Cord Syndrome in a Young Patient with Early Diffuse Idiopathic Skeletal Hyperostosis and Ossification of the Posterior Longitudinal Ligament after Minor Trauma: A Case Report and Review

This paper is a case report and literature review. The objective of this article is to address a rather unusual case of central cord syndrome in a patient with diffuse idiopathic skeletal hyperostosis and focal ossification of the posterior longitudinal ligament. We also discuss the mechanism of injury in central cord syndrome, as well as that specific to involvement of diffuse idiopathic skeletal hyperostosis (DISH) and ossification of the posterior longitudinal ligament (OPLL). This case took place at SUNY Upstate Medical University. We report a case of a 39-year-old male with early diffuse idiopathic skeletal hyperostosis and focal ossification of the posterior longitudinal ligament, presenting with central cord syndrome after minor trauma. The patient presented with tetraparesis, predominating with significant distal upper extremity weakness and hyperpathia. We performed a C3-6 decompressive laminectomy, with C2 pars screws, and C3-7 lateral mass screws. Since surgery, the patient has had a steady progressive improvement in neurological function and is currently ambulating with a good functional use of his upper extremities. An increased risk of spinal cord injury is a known risk in individuals with pre-existing spinal ankylosing. Few reports are present citing the contribution of focal OPLL with DISH in this age group within the cervical spine contributing to the central cord syndrome.

Clinics in diagnostic imaging (161). Cervical OPLL with cord compression

A 53-year-old man presented with acute cervical myelopathy following a fall. Cervical radiography and computed tomography showed ossification of the posterior longitudinal ligament (OPLL) from C2 to C6 level, with severe cervical canal stenosis and cord compression. Magnetic resonance imaging further showed increased T2-weighted signal in the spinal cord at the level of greatest central spinal canal stenosis. OPLL is a significant cause of myelopathy in Asian populations and is found in up to 25% of patients presenting with cervical compression myelopathy. The clinical presentation, radiological evaluation and management of OPLL are discussed.

Gradual spinal cord decompression through migration of floated plaques after anterior decompression via a posterolateral approach for OPLL in the thoracic spine

OBJECT

Several surgical procedures have been developed to treat thoracic OPLL (ossification of the posterior longitudinal ligament). However, favorable surgical results are not always achieved, and consistent protocols and procedures for surgical treatment of OPLL in this region have not been established. Beak-type OPLL in the thoracic spine is known to be the most complicated form of OPLL to treat surgically. In this study, the authors examine the clinical outcomes after anterior decompression via a posterolateral approach for beak-type OPLL in the thoracic spine and address the gradual spinal cord decompression caused by migration of the floated plaques after surgery.

METHODS

Between 2011 and 2013, a total of 12 patients with thoracic myelopathy due to OPLL were surgically treated at the authors' institute. The study group for this paper comprises 6 of those 12 patients. These 6 patients, who had beak-type OPLL, underwent with anterior decompression and instrumented fusion via the authors' posterolateral approach-based surgical technique. The other 6 patients, who exhibited other types of OPLL, underwent posterior decompression and instrumented fusion. In the study group (the 6 patients with beak-type OPLL), half of the patients (the 3 patients who were treated first) were treated with removal of the ossified ligament. These patients are referred to as the removal group. The other 3 patients were treated by means of "floating" the OPLL plaques and are referred to as the floating group. Clinical and radiographic outcomes were evaluated in these 6 cases.

RESULTS

The recovery rates were 52.4% in the removal group and 60.0% in the floating group. Two patients in the removal group had operative complications, including a dural tear and temporary neurological deterioration. No operative complications were encountered in the floating group. In all 3 cases in the floating group, floating of the ossified ligament was completely achieved, and the floated plaque gradually migrated into the ventral bone resection areas. The mean migration distances of the floated plaque were 2.4 mm, 4.3 mm, 4.7 mm, and 4.8 mm at 1, 3, 6, and 12 months after surgery.

CONCLUSIONS

Treatment of beak-type OPLL in the thoracic spine via the posterolateral approach-based floating plaque technique was safe and effective in this small case series. Gradual migration of the floated plaques provided additional spinal cord decompression during the postoperative course.

Prognostic factors for surgical outcome in spinal cord injury associated with ossification of the posterior longitudinal ligament (OPLL)

BACKGROUND

Ossification of the posterior longitudinal ligament (OPLL) may increase the risk of spinal cord injury (SCI) with various neurological deficits after minor trauma. However, few studies have investigated the influence of OPLL on neurological outcome after acute cord injury. We examined whether severe spinal canal stenosis caused by OPLL affects neurological outcome after SCI based on intramedullary signal intensity (SI) changes on magnetic resonance imaging (MRI).

METHODS

From June 2006 to July 2013, we treated 246 patients with cervical cord injury. Fifty-one (20.7%) patients had ventral cord compression due to OPLL without any bony fractures. Among them, 38 patients (34 men, mean age 62.7 years) underwent cervical laminoplasty (8) and cervical decompression and fixation (30). The neurologic assessments were performed in patients who had 1-year follow-up, and the mean follow-up period was 42.2 months. OPLL type, cause of injury, cervical sagittal angle, cervical spine stenosis, cord compression ratio (space available for the spinal cord (SAC)), and grade of intramedullary SI (grade 0, none; grade 1, light; grade 2, intense T2WI) were assessed.

RESULTS

Mean American Spinal Injury Association (ASIA) motor score at admission was 38.4 ± 21.9 (range, 2-70) and improved to 67.7 ± 19.1 (range, 8-94) at last follow-up (p < 0.05). Mean recovery rate of the motor score was 55.8 ± 19.9%. Five patients had SI grade 0, 20 patients had SI grade 1, and 13 patients had SI grade 2. Among the variables tested, age, initial ASIA motor grade, intramedullary SI grade, and SAC were significantly related to neurological outcome. However, initial cervical alignment, canal diameter, length of SI, time interval between injury and operation, and OPLL type had no significant effect on neurological outcome.

CONCLUSIONS

Preoperative neurological status, cord compression ratio, and SI grade are related to neurological outcome in patients with SCI associated with OPLL. The better the preoperative neurological status, the more favorable the neurological outcome after surgery. A higher SI grade on preoperative T2WI was negatively related to neurological outcome. Therefore, the severity of SI change, cord compression ratio, and preoperative neurological status can be regarded as significant prognostic factors in patients with SCI associated with OPLL.

Adverse effect of trauma on neurologic recovery for patients with cervical ossification of the posterior longitudinal ligament

Study Design Retrospective study. Objective Minor trauma, even from a simple fall, can often cause cervical myelopathy, necessitating surgery in elderly patients who may be unaware of their posterior longitudinal ligament ossification (OPLL). The aim of this study is to determine the influence of trauma on the neurologic course in patients who have undergone surgery for cervical OPLL. Methods Patients who underwent surgery due to OPLL were divided by trauma history and compared (34 in the trauma group; 70 in the nontrauma group). Results Ground falls were the most common type of trauma (20 patients, low-energy injuries), but 23 patients developed new symptoms after a trauma. Although the symptom duration (17.68 months) was shorter, the Japanese Orthopedic Association (JOA) score and the Nurick scale showed lower values in the trauma group. Trauma histories led patients to earlier hospital visits. Initial JOA scores were associated with a good recovery status upon the last follow-up in both the groups. The narrowest diameter of the spinal canal showed different radiologic parameters: 5.78 mm in the trauma group and 6.52 mm in the nontrauma group. Conclusion Minor trauma can cause the unexpected development of new symptoms in patients unaware of cervical OPLL. Patients with a history of trauma had lower initial JOA scores and showed a narrower spinal canal compared with a nontrauma group. The initial JOA scores were correlated with a good recovery status upon the last follow-up.

The impact of dynamic factors on surgical outcomes after double-door laminoplasty for ossification of the posterior longitudinal ligament of the cervical spine

OBJECT

Laminoplasty is the preferred operation for most patients with cervical myelopathy due to multilevel ossification of the posterior longitudinal ligament (OPLL). Recent studies have demonstrated several significant risk factors for poor clinical outcomes after laminoplasty, including older age, lower preoperative Japanese Orthopaedic Association (JOA) score, postoperative change in cervical alignment, cervical kyphosis, and high occupying ratio of the OPLL (that is, the ratio of the greatest anteroposterior thickness of the OPLL to the anteroposterior diameter of the spinal canal at the same level on a lateral image). However, the impact of dynamic factors on clinical outcomes is unclear. The purpose of this study is to assess the impact of dynamic factors on the clinical outcome after laminoplasty for cervical myelopathy due to OPLL.

METHODS

A consecutive series of patients who underwent laminoplasty for cervical myelopathy due to OPLL between 2003 and 2009 was retrospectively reviewed. The indication for laminoplasty at the authors' hospital included preoperative straight or lordotic alignment of the cervical spine and an occupying ratio of OPLL less than 60%. The JOA score and recovery rate were used to evaluate clinical outcomes. A poor clinical outcome was defined as a recovery rate of less than 50%. Patient factors examined along with outcome included age, preoperative JOA score, preoperative somatosensory evoked potentials, preoperative motor evoked potentials, body mass index, and presence of high intensity on MRI. Radiographic measures included the preoperative C2-7 lordotic angle, preoperative C2-7 range of motion (ROM), preoperative segmental ROM at the level of myelopathy, and the occupying ratio of OPLL.

RESULTS

There were 45 patients (33 males and 12 females). The mean follow-up period was 4 years (range 2-6.8 years). The mean patient age was 66.9 years (range 50-85 years). The mean JOA score significantly increased from 9.1 before surgery to 13.1 at the final follow-up. The mean recovery rate was 51.2%. Nineteen patients (42%) had a recovery rate of less than 50%. Patient factors were not associated with surgical outcomes. Only the preoperative C2-7 ROM was significantly greater in the poor surgical outcome group (23.1° vs 14.1°). Receiver operating characteristic curve analysis showed that the optimal preoperative C2-7 ROM cutoff was 20°. Logistic regression analysis revealed that patients with a preoperative C2-7 ROM of greater than 20° had a 4.6 times higher risk (p = 0.021) of a poor clinical outcome, indicating that dynamic factors may have an impact on the surgical outcome of laminoplasty.

CONCLUSIONS

Fusion surgery may be a useful strategy in patients with preoperative hypermobility of the cervical spine.

Progression of ossification of the posterior longitudinal ligament of the thoracic spine following posterior decompression and stabilization

OBJECT

Despite its potential clinical impact, information regarding progression of thoracic ossification of the posterior longitudinal ligament (OPLL) is scarce. Posterior decompression with stabilization is currently the primary surgical treatment for symptomatic thoracic OPLL; however, it remains unclear whether thoracic OPLL increases in size following spinal stabilization. It is also unknown whether patients' clinical symptoms worsen as OPLL size increases. In this retrospective case series study, the authors examined the postoperative progression of thoracic OPLL.

METHODS

Nine consecutive patients with thoracic OPLL who underwent posterior decompression and fixation with a minimum follow-up of 3 years were included in this study. Thin-slice CT scans of the thoracic spine obtained at the time of surgery and the most recent follow-up were analyzed. The level of the most obvious protrusion of ossification was determined using the sagittal reconstructions, and the ossified area was measured on the axial reconstructed scan at the level of the most obvious protrusion of ossification using the DICOM (digital imaging and communications in medicine) software program. Myelopathy severity was assessed according to the Japanese Orthopaedic Association (JOA) scale score for lower-limb motor function on admission, at postoperative discharge, and at the last follow-up visit.

RESULTS

The OPLL area was increased in all patients. The mean area of ossification increased from 83.6 ± 25.3 mm(2) at the time of surgery to 114.8 ± 32.4 mm(2) at the last follow-up visit. No patients exhibited any neurological deterioration due to OPLL progression.

CONCLUSIONS

The present study demonstrated that the size of the thoracic OPLL increased after spinal stabilization. Despite diminished local spinal motion, OPLL progression did not decrease or stop. Physicians should pay attention to ossification progression in patients with thoracic OPLL.

Biomechanical analysis of cervical myelopathy due to ossification of the posterior longitudinal ligament: Effects of posterior decompression and kyphosis following decompression

Cervical ossification of the posterior longitudinal ligament (OPLL) results in myelopathy. Conservative treatment is usually ineffective, thus, surgical treatment is required. One of the reasons for the poor surgical outcome following laminoplasty for cervical OPLL is kyphosis. In the present study, a 3-dimensional finite element method (3D-FEM) was used to analyze the stress distribution in preoperative, posterior decompression and kyphosis models of OPLL. The 3D-FEM spinal cord model established in this study consisted of gray and white matter, as well as pia mater. For the preoperative model, 30% anterior static compression was applied to OPLL. For the posterior decompression model, the lamina was shifted backwards and for the kyphosis model, the spinal cord was studied at 10, 20, 30, 40 and 50° kyphosis. In the preoperative model, high stress distributions were observed in the spinal cord. In the posterior decompression model, stresses were lower than those observed in the preoperative model. In the kyphosis model, an increase in the angle of kyphosis resulted in augmented stress on the spinal cord. Therefore, the results of the present study indicated that posterior decompression was effective, but stress distribution increased with the progression of kyphosis. In cases where kyphosis progresses following surgery, detailed follow-ups are required in case the symptoms worsen.

A case of paraparesis with thoracic ossification of the posterior longitudinal ligament and the ligamentum flavum induced by falling down on the abdomen

Aim

To describe an educational case.

Methods

Case report.

Results

A 71-year-old female was transported to our emergency department with complaints of lower abdominal pain and gate disturbance after falling down on her abdomen. She had lower abdominal painful paresthesia in the dermatome from the twelfth thoracic to the first lumbar level without signs of peritoneal stimulation. Paraparesis and dysesthesia of the lower extremities was predominant on the left side. Abdominal computed tomography revealed severe thoracic ossification of the posterior longitudinal ligament and the ligamentum flavum at the thoracic level 10/11. Laminectomy and spinal fusion with rods resulted in recovery of the patient's symptoms.

Conclusion

Physician should pay attention to thoracic spinal cord injury induced by hyperextensive stress on the spine, even in cases of minor trauma, among patients with preexisting bony pathologies at the thoracolumbar level.

Ossification of the posterior longitudinal ligament related genes identification using microarray gene expression profiling and bioinformatics analysis

Ossification of the posterior longitudinal ligament (OPLL) is a kind of disease with physical barriers and neurological disorders. The objective of this study was to explore the differentially expressed genes (DEGs) in OPLL patient ligament cells and identify the target sites for the prevention and treatment of OPLL in clinic. Gene expression data GSE5464 was downloaded from Gene Expression Omnibus; then DEGs were screened by limma package in R language, and changed functions and pathways of OPLL cells compared to normal cells were identified by DAVID (The Database for Annotation, Visualization and Integrated Discovery); finally, an interaction network of DEGs was constructed by string. A total of 1536 DEGs were screened, with 31 down-regulated and 1505 up-regulated genes. Response to wounding function and Toll-like receptor signaling pathway may involve in the development of OPLL. Genes, such as PDGFB, PRDX2 may involve in OPLL through response to wounding function. Toll-like receptor signaling pathway enriched genes such as TLR1, TLR5, and TLR7 may involve in spine cord injury in OPLL. PIK3R1 was the hub gene in the network of DEGs with the highest degree; INSR was one of the most closely related genes of it. OPLL related genes screened by microarray gene expression profiling and bioinformatics analysis may be helpful for elucidating the mechanism of OPLL.

Combined ossification of the posterior longitudinal ligament at C2-3 and invagination of the posterior axis resulting in myelopathy

PURPOSE

Spinal stenosis at the C2-3 segment is a rare occurrence, and when it occurs myelopathy infrequently results. Furthermore, only a handful of cases involving congenital abnormalities of the posterior arch of the axis have been described resulting in cervical myelopathy many of which described simultaneous congenital abnormalities at adjacent levels and none of which identified ossification of the posterior longitudinal ligament (OPLL) at the same level. We report a case of a previously undescribed combination of abnormalities at the C2-3 segment resulting in clinical myelopathy.

METHODS

A 49-year-old Chinese male presented with a progressive cervical myelopathy (C-JOA score 11 immediately pre-op). Segmental OPLL at the C2-3 disk space was visible, together with invagination of the bilaterally hypoplastic C2 lamina into the spinal canal. Signal abnormalities of the spinal cord were evident on both T1 and T2 sequences.

RESULTS

The patient underwent a posterior decompression and instrumented fusion at C2-3 using pars screws at C2 and lateral mass screws at C3. Following surgery there was a rapid and significant improvement in the neurological symptoms, with the C-JOA score improving to 14 at final follow-up. A successful fusion was evident.

CONCLUSIONS

Deficiencies in the posterior arch of the axis are rare and have not previously been reported in conjunction with OPLL. Advanced imaging is helpful to define the abnormality and site of compression. In the setting of a progressive neurological dysfunction, surgical decompression and stabilization is a reasonable intervention and can be associated with neurological and symptomatic improvement.

Post-myelography paraplegia in a woman with thoracic stenosis

CONTEXT

Myelography is a commonly performed diagnostic test used to assess spine pathology. Complications are unusual and usually self-limited. We report a rare case of transient paraplegia following myelography in a woman with thoracic stenosis.

FINDINGS

A 51-year-old woman, 20 months status post-thoracic laminectomy, presented with progressive lower extremity weakness. The patient underwent myelography and post-myelography CT, and became paraplegic after the lumbar injection. Intravenous steroids were administered and a lumbar puncture was performed. The patient's neurologic function returned to baseline over the next 96 hours.

CONCLUSION AND CLINICAL RELEVANCE

Myelography is generally a safe procedure, but on rare occasions serious complications can arise. Therapeutic maneuvers may be helpful in reversing neurologic deficit.

Biomechanical study of the spinal cord in thoracic ossification of the posterior longitudinal ligament

BACKGROUND

Ossification of the posterior longitudinal ligament (OPLL) in the thoracic spine produces myelopathy. This is often progressive and is not affected by conservative treatment. Therefore, decompressive surgery is usually chosen.

OBJECTIVE

To conduct a stress analysis of the thoracic OPLL.

METHODS

The three-dimensional finite element spinal cord model was established. We used local ossification angle (LOA) for the degree of compression of spinal cord. LOA was the medial angle at the intersection between a line from the superior posterior margin at the cranial vertebral body of maximum OPLL to the top of OPLL with beak type, and a line from the lower posterior margin at the caudal vertebral body of the maximum OPLL to the top of OPLL with beak type. LOA 20°, LOA 25°, and LOA 30° compression was applied to the spinal cord in a preoperative model, the posterior decompressive model, and a model for the development of kyphosis.

RESULTS

In a preoperative model, at more than LOA 20° compression, high stress distributions in the spinal cord were observed. In a posterior decompressive model, the stresses were lower than in the preoperative model. In the model for development of kyphosis, high-stress distributions were observed in the spinal cord at more than LOA 20° compression.

CONCLUSIONS

Posterior decompression was an effective operative method. However, when the preoperative LOA is more than 20°, it is very likely that symptoms will worsen. If operation is performed at greater than LOA 20°, then correction of kyphosis by fixation of instruments or by forward decompression should be considered.

Flexion model simulating spinal cord injury without radiographic abnormality in patients with ossification of the longitudinal ligament: the influence of flexion speed on the cervical spine

BACKGROUND/OBJECTIVE

It is suspected that the speed of the motion of the spinal cord under static compression may be the cause of spinal cord injury (SCI). However, little is known about the relationship between the speed of the motion of the spinal cord and its stress distributions. The objective was to carry out a biomechanical study of SCI in patients with ossification of the longitudinal ligament without radiologic evidence of injury.

METHODS

A 3-dimensional finite element spinal cord model was established. After the application of static compression, the model underwent anterior flexion to simulate SCI in ossification of the longitudinal ligament patients without radiologic abnormality. Flexion of the spine was assumed to occur at 1 motor segment. Flexion angle was 5 degrees, and flexion speeds were 0.5 degrees/s, 5 degrees/s, and 50 degrees/s. Stress distributions inside of the spinal cord were evaluated.

RESULTS

Stresses on the spinal cord increased slightly after the application of 5 degrees of flexion at a speed of 0.5 degrees/s. Stresses became much higher at a speed of 5 degrees/s and increased further at 50 degrees s.

CONCLUSIONS

The stress distribution of the spinal cord under static compression increased with faster flexion speed of the spinal cord. High-speed motion of the spinal cord under static compression may be one of the causes of SCI in the absence of radiologic abnormality.