Simultaneous ossification of the posterior longitudinal ligament and ossification of the ligamentum flavum causing upper thoracic myelopathy in DISH: case report and literature review

Biological mechanisms underlying the ossification of ligamentum flavum and potential therapeutic targets derived from current research

PURPOSE

Ossification of ligament flavum (OLF), a prevalent cause of thoracic myelopathy, continues to present significant challenges for clinicians. While recent studies have illuminated various pathogenic molecular cascades associated with OLF. Comprehensive review of the underlying signaling pathways involved in its development remains absent from the literature. This study aims to synthesize and critically discuss the current evidence, providing a thorough overview of the progress made in the understanding OLF pathogenesis.

METHODS

A comprehensive literature search was conducted using PubMed, Medline, Web of Science, ChiCTR.org.cn, and ClinicalTrials.gov databases to identify studies investigating the mechanisms involved in the development of OLF. The selected studies were categorized based on the type of mechanism explored. Initialing factors were summarized in tables and figures, and the related content were discussed systematically discussed.

RESULTS

The mechanisms underlying OLF formation primarily involve genetic background and modification, mechanical stress, osteogenesis-related proteins, non-coding RibonucleicAcid (RNA) and metabolism. However, clinical trials reporting the translational application of these existing mechanisms were scarce.

CONCLUSIONS

The formation and development of OLF are multi-factorial, and the underlying mechanisms have been preliminarily elucidated. Future research should focus on the clinical application of these mechanisms. This review may provide a theoretical basis for the development of therapeutic agents and offer new perspectives further studies on OLF.

Imaging review of the atypical spinal epidural space pathologies

Pathologies affecting the spinal epidural space (SES) comprise various abnormalities. However, they all have the potential to cause thecal sac narrowing or spinal cord compression. In this review, we group these pathologies into degenerative, infective, neoplastic, vascular, traumatic, and others, focusing on their imaging features. Degenerative pathologies of the SES range from disc to facet disease, with a particular emphasis on the less common degenerative pathologies in this review. Infective pathologies affecting the epidural space include spondylodiscitis and associated epidural phlegmon and abscess. Neoplasms arising from typical SES components include neurofibroma, hemangioma, and liposarcoma. MRI is the best modality to assess the anatomy and abnormalities of the epidural space. MRI, combined with computed tomography, or a radiograph, is useful for the evaluation of bones or radiopaque foreign bodies.

The Symptomatic Calcification and Ossification of the Ligamentum Flavum in the Spine: Our Experience and Review of the Literature

INTRODUCTION

We report our experience regarding the clinical features and pathological findings of the calcification of the ligamentum flavum (CLF) and ossification of the ligamentum flavum (OLF) in the spine. In addition, we reviewed the previous studies on CLF and OLF to enhance the understanding of these conditions.

MATERIALS AND METHODS

We compared the clinical, radiological, and histopathological features of CLF and OLF.

RESULTS

In CLF, a computed tomography (CT) scan showed egg-shaped or speck-like calcification in the ligamentum flavum. Magnetic resonance (MR) imaging demonstrated spinal cord compression due to a thickened ligamentum flavum, which appeared as a low-intensity mass. Pathological findings demonstrated fused islands of calcification resembling sand-like calcification. In OLF, CT showed beak-like ossification extending into the intervertebral foramen. MR imaging demonstrated spinal cord compression by a low-intensity mass. Pathological findings revealed laminar ossification of LF with chondrocytes near the calcification and laminar hyaline cartilage.

CONCLUSIONS

CLF and OLF appear to be distinct entities based on their clinical, neuroradiological, histopathological, and pathogenetic features. We suggest that the causes of CLF include both metabolic and dystrophic factors, while the pathogenesis of OLF is characterized by enchondral ossification induced by a genetic cascade triggered by shearing/tension stress.

Clinical progression of ossification of the ligamentum flavum in thoracic spine: a 10- to 11-year follow-up study

BACKGROUND

Thoracic ossification of ligamentum flavum (TOLF) can be asymptomatic and progress insidiously. But, long-term follow-up results of clinical progression of TOLF are still unknown.

METHODS

The clinical progression of 81 patients with TOLF at our center, followed for 10 to 11 (mean, 10.3) years from May 2010 to November 2021, were analyzed. Among them, 51 patients with thoracic myelopathy were caused by single- or multi-segment TOLF, and received partial TOLF resection (30 patients) or total TOLF resection (21 patients). The remaining 30 patients showed TOLF on imaging examinations, but TOLF was not the responsible compressing factor causing myelopathy and with no TOLF resection. The mJOA score (total 11 scores) and spinal operation were used to evaluate the clinical progression at follow-up.

RESULTS

During the 10- to 11-year follow-up of 81 TOLF patients, 71 (87.7%) had no deterioration of neurological function, and 10 (12.3%) patients had deterioration of neurological function and had another spinal operation, including only 4 (4.9%) suffered thoracic myelopathy caused by the progression of TOLF; 6 (7.4%) for other spinal diseases: 2 (2.5%) had fall damage and acute spinal cord injury at the TOLF level; 2 (2.5%) had thoracic myelopathy caused by ossification of posterior longitudinal ligament (OPLL); 2 (2.5%) had cervical spondylosis and received cervical operation.

CONCLUSIONS

Most TOLF (87.7%) patients had no clinical progression and received no reoperations for TOLF in the ten-year dimension (mean, 10.3 years). Narrow spinal canal for TOLF increases the risk of traumatic paraplegia.

Evidence for a genetic contribution to the ossification of spinal ligaments in Ossification of Posterior Longitudinal Ligament and Diffuse idiopathic skeletal hyperostosis: A narrative review

Diffuse Idiopathic Skeletal Hyperostosis (DISH) and Ossification of the Posterior Longitudinal Ligament (OPLL) are common disorders characterized by the ossification of spinal ligaments. The cause for this ossification is currently unknown but a genetic contribution has been hypothesized. Over the last decade, many studies on the genetics of ectopic calcification disorders have been performed, mainly on OPLL. Most of these studies were based on linkage analysis and case control association studies. Animal models have provided some clues but so far, the involvement of the identified genes has not been confirmed in human cases. In the last few years, many common variants in several genes have been associated with OPLL. However, these associations have not been at definitive levels of significance and evidence of functional significance is generally modest. The current evidence suggests a multifactorial aetiopathogenesis for DISH and OPLL with a subset of cases showing a stronger genetic component.

Association between Severity of Diffuse Idiopathic Skeletal Hyperostosis and Ossification of Other Spinal Ligaments in Patients with Ossification of the Posterior Longitudinal Ligament

BACKGROUND

Although diffuse idiopathic skeletal hyperostosis (DISH) is known to coexist with the ossification of spinal ligaments (OSLs), details of the radiographic relationship remain unclear.

METHODS

We prospectively collected data of 239 patients with symptomatic cervical ossification of the posterior longitudinal ligament (OPLL) and analyzed the DISH severity on whole-spine computed tomography images, using the following grades: grade 0, no DISH; grade 1, DISH at T3-T10; grade 2, DISH at both T3-T10 and C6-T2 and/or T11-L2; and grade 3, DISH beyond C5 and/or L3. Ossification indices were calculated as the sum of vertebral and intervertebral levels with OSL for each patient.

RESULTS

DISH was found in 107 patients (44.8%), 65 (60.7%) of whom had grade 2 DISH. We found significant associations of DISH grade with the indices for cervical OPLL (r = 0.45, p < 0.0001), thoracic ossification of the ligamentum flavum (OLF; r = 0.41, p < 0.0001) and thoracic ossification of the supra/interspinous ligaments (OSIL; r = 0.53, p < 0.0001). DISH grade was also correlated with the index for each OSL in the whole spine (OPLL: r = 0.29, p < 0.0001; OLF: r = 0.40, p < 0.0001; OSIL: r = 0.50, p < 0.0001).

CONCLUSION

The DISH grade correlated with the indices of OSL at each high-prevalence level as well as the whole spine.

Thoracic ligamentum flavum ossification: a rare cause of spinal cord injury without tomographic evidence of trauma in a Caucasian patient. Case report and literature review

INTRODUCTION

Acute spinal cord injury without tomographic evidence of vertebral fracture or dislocation in patients post trauma can represent a diagnostic challenge for the treating physician. The ossification of thoracic ligamentum flavum has been widely published as a cause of thoracic myelopathy, however its association with acute traumatic spinal cord injury is limited to isolated cases.

CASE PRESENTATION

we report a Caucasian 37-year-old man who suffered a high-energy thoracolumbar spine trauma in a motorcycle accident with acute paraplegia. He presented ossification of the ligamentum flavum between the thoracic vertebrae T10 and T11 with a decrease in the diameter of the vertebral canal as the only pathological finding. We treated the patient with early surgical release before 72 h of trauma. We performed a posterior approach with hemilaminectomy and T10-T11 flavectomy. Arthrodesis was done with T10-T11 pedicle screws. Postoperative neurological status improved from ASIA Impairment Scale (AIS) A to C with severe functional dependence.

DISCUSSION

Ossification of the ligamentum flavum should be considered in the differential diagnosis in patients presenting with acute traumatic spinal cord injury without tomographic evidence of trauma. A proper diagnosis in time is the key to decision making and treatment of spinal cord injury. Especially in adult patients, we must consider nontraumatic associated factors that could be involved in the spinal cord injury mechanism, such as ossification of the ligamentum flavum.

circSKIL promotes the ossification of cervical posterior longitudinal ligament by activating the JNK/STAT3 pathway

Ossification of the posterior longitudinal ligament (OPLL) is a hyperostotic spinal condition that involves genetic factors as well as non-genetic factors, and its underlying molecular mechanism is largely unknown. Recently, circular RNAs (circRNAs) have been attracting the attention of researchers since they have important regulatory roles in many diseases, including bone metabolism disorders. The present study aimed to investigate the role of circRNA SKI-like proto-oncogene (circSKIL) in OPLL disease progression. First, primary posterior longitudinal ligament cells from patients with cervical spondylotic myelopathy (CSM) without OPLL (control group) and CSM patients with OPLL (OPLL group) were isolated, and the expression levels of circSKIL in ligament cells was found to be significantly increased in the OPLL group compared with control. This result was also confirmed in OPLL tissues. Next, circSKIL was overexpressed in control ligament cells, and the proliferation, mineralization, and osteogenic differentiation of ligament cells were found to be significantly enhanced; the phosphorylation levels of both JNK and STAT3 were upregulated. By contrast, the knockdown of circSKIL in OPLL ligament cells inhibited proliferation, mineralization, and osteogenic differentiation and inactivated the JNK/STAT3 pathway. Therefore, circSKIL may have a significant role in osteogenic differentiation and could serve as a potential target to prevent OPLL progression.

New Classification Algorithm Guiding Surgical Decision-making for Posterior Longitudinal Ligament Ossification of the Thoracic Spine: A Study of 108 Patients With Mid-term to Long-term Follow-up

STUDY DESIGN

This is a single-center, retrospective, cohort study.

OBJECTIVE

The objective of this study was to propose a surgical classification algorithm guiding the choice of surgical approaches for ossification of the posterior longitudinal ligament (OPLL) in the thoracic spine based on the characteristics of each patient's specific pathology.

SUMMARY OF BACKGROUND DATA

Surgical decision-making in this OPLL patient population requires balancing a more definitive decompression of the thoracic spinal cord through direct decompression against a higher risk of significant complications.

MATERIALS AND METHODS

Patients with a primary diagnosis of thoracic OPLL who received surgical decompression in a tertiary spine center between May 2009 and June 2015 were included. Surgical planning was guided by our classification algorithm according to the location and the extent of OPLL in each patient. Patient demographics, neurological function using the 11-point Japanese Orthopaedic Association scale, length of procedure, estimated blood loss, the occurrence of major complications, etc., were extracted from the database of electronic medical record system. The Kruskal-Wallis test and Fisher exact test were used when data were not normally distributed.

RESULTS

A total of 115 patients (33 men and 82 women) were included in this study, among whom 108 had a follow-up of at least 12 months (average: 51.7±22.2 mo, range: 12-100 mo). On the basis of our classification algorithm, 11 patients were type I, 26 were type II, 60 were type III, 11 were type IV, and the choice of surgical decompression techniques used in each patient followed that recommended by the algorithm in all cases. On average, the Japanese Orthopaedic Association score improved from 5.0±1.8 preoperatively to 8.7±1.7 postoperatively, with a Hirabayashi improvement rate of 63.6%.

CONCLUSION

A new surgical classification algorithm guiding the choice of approach for decompression of OPLL in the thoracic spine was validated in a series of 108 patients through an analysis of their clinical outcomes and surgical complications.

LEVEL OF EVIDENCE

Level III.

One-stage posterior surgery with intraoperative ultrasound assistance for thoracic myelopathy with simultaneous ossification of the posterior longitudinal ligament and ligamentum flavum at the same segment: a minimum 5-year follow-up study

BACKGROUND CONTEXT

Ossification of the posterior longitudinal ligament (OPLL) and ligamentum flavum (OLF) are not uncommon independent causes of thoracic myelopathy (TM); however, concomitant OPLL and OLF at the same segment is rare. The ideal surgical strategy remains controversial, and it is difficult for surgeons to balance sufficient neural decompression while simultaneously reducing the occurrence of postoperative neurological defect after circumferential decompression (CD). Aiming to solve this dilemma, we investigated a CD-based surgery using intraoperative ultrasound (IOU) assistance to evaluate spinal decompression sufficiency.

PURPOSE

The aims of this study are to evaluate the surgical outcomes and identify prognostic factors of one-stage posterior surgery with IOU assistance in patients with concomitant OPLL and OLF.

STUDY DESIGN/SETTING

Retrospective study of a single-center TM database with long-term follow-up.

PATIENT SAMPLE

Twenty-four patients with TM and concomitant OPLL and OLF.

OUTCOME MEASURES

Japanese Orthopaedic Association (JOA) score system for TM, recovery rate (RR), complication rate.

METHODS

Twenty-four patients' data were retrospectively reviewed. All patients initially underwent en bloc excisions of posterior spinal canal elements, and IOU was then used to evaluate spinal decompression sufficiency. If any compression of OPLL was confirmed in IOU, further CD procedure was performed. The JOA score was used to evaluate health-related quality of life. RR was calculated using the Hirabayashi formula. A RR ≥50% was considered favorable, and a RR <50% was considered unfavorable. The paired t test was performed to statistically compare the preoperative and postoperative JOA scores. The chi-squared test, rank sum test, and logistic regression analyses were performed to find variants associated with unfavorable surgical outcomes The prognostic factors were analyzed by Spearman correlation and Pearson correlation analyses.

RESULTS

The invasive CD procedure were avoided in 9 of 28 segments were avoided, with a mean blood loss of 1,458 mL. Seventeen patients experienced cerebrospinal fluid leakage, and 5 experienced immediate postoperative paralysis. The mean JOA score improved from 4.25±2.2 (preoperative) to 8.16±1.9 (final follow-up). The mean RR was 57.7%±29.4%. There was a significant difference (p<.01) between the preoperative and final follow-up JOA score. A comparison between the favorable and the unfavorable groups showed no significant differences in the evaluated factors, but the considerable blood loss was a significant risk factor for poor RR (p=.036, b=-0.43).

CONCLUSIONS

One-stage CD-based surgery via a posterior approach with IOU assistance for the treatment of concomitant OPLL and OLF led to significant functional improvement in the majority of patients. Under the premise of sufficient decompression, the postoperative paralysis rate reduced compared to that in previous studies. However, there were still high cerebral spinal fluid leakage rates. Considerable blood loss is a risk factor for poor RR.

Association between ossification of the posterior longitudinal ligament and ossification of the nuchal ligament in the cervical spine

OBJECTIVES

To investigate the association between ossification of the posterior longitudinal ligament (OPLL) and ossification of the nuchal ligament (ONL) in terms of incidence and size.

METHODS

This retrospective study evaluated 297 patients who underwent CT of the cervical spine (C-spine). Two radiologists worked in consensus. The incidence of OPLL from patients with and without ONL was compared using Chi Square tests. The mean lengths of ONL from patients with and without OPLL were compared using Student t-test. The correlations between the length of ONL and the presence of OPLL and between the length of ONL and the length of OPLL were analyzed with Pearson correlations.

RESULTS

We found that OPLL occurred more frequently in patients with ONL than in patients without ONL (odd ratio = 2.524, p = 0.037); however, the mean length of ONL did not differ significantly patients with and without OPLL (p = 0.874). We found no significant correlation between the length of ONL and the length of OPLL (p = 0.233).

CONCLUSION

The presence of ONL was associated with the presence of OPLL. The length of OPLL and ONL showed no correlation.

Two-Staged Circumferential Decompression and Fusion Surgery for Upper Thoracic Myelopathy Caused by Concurrent Beak-Type Ossification of the Posterior Longitudinal Ligament and Ligamentum Flavum at T1-T2 Level: A Case Report

BACKGROUND

Upper thoracic myelopathy caused by combined ossification of the posterior longitudinal ligament (OPLL) and ossification of the ligamentum flavum (OLF) is relatively rare. This clinical condition is difficult to treat, and a surgical method has not been fully established. We report an extremely rare case of severe thoracic myelopathy caused by concurrent beak-type OPLL and OLF at T1-T2.

CASE DESCRIPTION

A 53-year-old woman with paresthesia of both legs and an inability to hold a standing position presented to our hospital. Radiological images showed a large beak-type OPLL at T1-T2 and an OLF at T1-T7. The spinal cord was severely compressed at T1-T2. First, posterior decompression and instrumentation fusion at C6-T4 was performed, with a T1-T2 bilateral parallel gutter along the dural tube into the vertebral bodies covering the extent of the OPLL. Second, anterior decompression of the OPLL with corpectomy of T1-T2 and fusion using iliac bone grafting was performed after the sternal manubrium splitting approach. In the deep operating field of the second surgery, the gutters created during the first surgery were helpful for judging the width and thickness of the OPLL during the anterior decompression procedure. Postoperatively, her neurological symptoms greatly improved, the patient could walk independently, and the Japanese Orthopaedic Association score had improved from 3 preoperatively to 8 at the final follow-up examination at 16 months postoperatively.

CONCLUSIONS

Two-stage circumferential decompression and fusion surgery can be considered an effective surgical method for upper thoracic concurrent OPLL and OLF. The bilateral gutters created during the first surgery improved the safety and feasibility of this difficult operation.

Cervical Myelopathy Secondary to Combined Ossification of Ligamentum Flavum and Posterior Longitudinal Ligament-A Case Report

In the cervical spine, the combined ossification of the ligamentum flavum (OLF) and posterior longitudinal ligament is rarely seen. Patients are usually treated with cervical laminectomy or laminoplasty with OLF resection. In most of the cases, OLF is adhered to the dura and there is a risk of dural tear or cerebrospinal fluid (CSF) leakage during its resection. In this case report, the authors present results of laminectomy with debulking instead of complete excision of OLF for spinal cord decompression in a cervical myelopathy case in which OLF was adhered to the dura. A 69-year-old man presented with insidious onset weakness in bilateral lower limbs and unsteady gait, which he had experienced 1 month. He has a history of neck pain with left upper limb radiation for the last 2 years. Magnetic resonance imaging showed C5-6 severe central canal stenosis with underlying myelomalacia. Computed tomography showed ossification posterior longitudinal ligament and OLF contributing to severe central canal stenosis at the C5-6 level. The patient underwent C4-C6 laminectomy, debulking of OLF, posterior instrumentation, and fusion with autogenous bone graft from C3 to C6. A histological specimen showed osseous tissue within the ligamentum flavum. After surgery the patient's symptoms improved and no recurrence was observed at 4 years after surgery. The symptoms of myelopathy were successfully treated with debulking instead of complete excision of OLF, thus reducing the risk of dural tear or CSF leakage.

Distribution of ossified spinal lesions in patients with severe ossification of the posterior longitudinal ligament and prediction of ossification at each segment based on the cervical OP index classification: a multicenter study (JOSL CT study)

BACKGROUND

In patients with ossification of the posterior longitudinal ligament (OPLL) in the cervical spine, it is well known that the thoracic ossified lesions often coexist with the cervical lesions and can cause severe myelopathy. However, the prevalence of OPLL at each level of the thoracic and lumbar spinal segments is unknown. The aims of this study were to investigate how often OPLL occurs at each level in the thoracolumbar spine in patients with a radiological diagnosis of cervical OPLL and to identify the spinal levels most likely to develop ossification.

METHODS

Data were collected from 20 institutions in Japan. Three hundred and twenty-two patients with a diagnosis of cervical OPLL were included. The OPLL index (OP index), defined as the sum of the vertebral body and intervertebral disc levels where OPLL is present, was used to determine disease severity. An OP index ≥20 was defined as severe OPLL. The prevalence of OPLL at each level of the thoracic and lumbar spinal segments was calculated.

RESULTS

Women were more likely to have ossified lesions in the thoracolumbar spine than men. Severe OPLL was significantly more common in women than in men (20% vs. 4.5%). For thoracic vertebral OPLL, the most frequently affected was the T1 segment in both men and women, followed by the T1/2 and T3/4 intervertebral levels in men and women, respectively. Ossified lesions were frequently seen at the intervertebral and vertebral levels around the cervicothoracic and thoracolumbar junctions in men with severe OPLL, whereas OPLL was more diffusely distributed in the thoracic spine in women with severe OPLL.

CONCLUSION

Thoracolumbar OPLL occurred most often at T1 in men and at T3/4 in women. In severe OPLL cases, although ossified lesions were frequently seen at the intervertebral and vertebral levels around the cervicothoracic and thoracolumbar junctions in men, OPLL could be observed more diffusely in the thoracic spine in women.

Increased Bone Mineral Density in Cervical or Thoracic Diffuse Idiopathic Skeletal Hyperostosis (DISH): A Case-Control Study

We aim to compare the bone mineral density (BMD) in a group of patients with cervical or thoracic diffuse idiopathic skeletal hyperostosis (DISH) with that in a matched control group. We also investigated the prevalence of osteoporosis in the two groups and determined the correlation between BMD and the extent of spinal DISH. From 1999 to July 2015, 65 patients with DISH underwent dual-energy X-ray absorptiometry at our institute. The control group was matched with regard to age, sex, and body mass index to the patient group on a 1:1 basis. BMD was measured at the lumbar spine (L1-L4), femur neck, and femur total areas using dual-energy X-ray absorptiometry. The BMDs of the DISH and control groups were significantly different at the lumbar spine (L1-L4) and the femur neck (p = 0.005, 0.001). The rates of patients with osteopenia and osteoporosis were lower in the DISH than in the control group for the lumbar spine (L1-L4) (p = 0.05). A positive correlation was observed between the lumbar spine (L1-L4) BMD and the number of spine levels affected by DISH (p = 0.04). The BMDs of the lumbar spine and femur neck were found to be higher in the DISH group than in a matched control group, when patients with lumbar DISH involvement were excluded. The rates of osteopenia and osteoporosis tended to be lower in the DISH group than in the control group. Lumbar spine BMD is significantly correlated with the number of spine levels affected by DISH.

Surgical Treatment for Thoracic Myelopathy Due to Simultaneous Ossification of the Posterior Longitudinal Ligament and Ligamentum Flavum at the Same Level

STUDY DESIGN

Retrospective review.

OBJECTIVE

The aim of this study was to assess the clinical outcomes of surgery in patients with simultaneous ossification of the posterior longitudinal ligament (OPLL) and ossification of the ligamentum flavum (OLF) at the same thoracic spine level and identify the risk factors for poor outcomes.

SUMMARY OF BACKGROUND DATA

OPLL complicated with OLF in the thoracic spine is a rare condition. The optimal treatment option for thoracic myelopathy due to OPLL and OLF remains controversial, and high risk of postoperative paralysis remains a major complication.

METHODS

We conducted a retrospective review of clinical and radiographic records of 15 patients who underwent surgery for simultaneous OPLL and OLF at the same level.

RESULTS

Simultaneous OPLL and OLF occurred in the upper thoracic spine in 3 patients (20%), mid-thoracic spine in 10 patients (67%), and lower thoracic spine in 2 patients (13%). Six, 4, 2, and 3 patients underwent posterior decompression, posterior decompression and fusion, posterior decompression and circumferential decompression through a posterior approach, and circumferential decompression and posterior fusion, respectively. The mean Japanese Orthopaedic Association score before surgery and at the final follow-up was 5.7±1.9 and 7.0±2.1 points, respectively, yielding a mean recovery rate of 16.5%. However, no significant difference was observed between preoperative and postoperative Japanese Orthopaedic Association scores. Two patients with mid-thoracic lesions reported postoperative lower extremity weakness. Mid-thoracic lesions and considerable blood loss were risk factors for poor surgical outcome.

CONCLUSIONS

Simultaneous OPLL and OLF in the mid-thoracic spine was observed in two thirds of the patients. We suggest that simultaneous OPLL and OLF in this area has a relatively poor recovery and may be very challenging and risky to treat, regardless of the surgical method selected, and recommend early surgery for OPLL and OLF in the mid-thoracic spine.

Acute traumatic cord injury associated with ossified ligamentum flavum

Ossification of the ligamentum flavum (OLF) is an uncommon condition, which usually occurs amongst people of Asian descent, and most commonly in the thoracic spine region. Whilst often asymptomatic, OLF can cause spinal canal stenosis, with patients presenting with back pain, posterior cord syndrome or myelopathy. We present a rare case of acute spinal cord injury associated with OLF after a kite surfing accident, with the resulting paraplegia partially improved after decompression was performed. The prevalence, presentation and management of OLF are also discussed.

One-staged combined decompression for the patients with cervico-thoracic tandem spinal stenosis

PURPOSE

To report the techniques and safety of one-staged combined decompression for the patients with tandem spinal stenosis (TSS) at cervical and thoracic spine.

METHODS

Sixteen TSS subjects, who received combined decompression from Aug 2005 to Feb 2012, were reviewed. The essentials of our surgical strategy included: choosing patients with TSS from cervical to upper or middle thoracic spine, using one single posterior incision, simplifying surgical maneuvers and performing circumferential decompression for thoracic compression if it was indicated. The Japanese Orthopedic Association (JOA) scale for cervical myelopathy was employed to evaluate the neurological status, and Hirabayashi's system to assess neurological recovery rate.

RESULTS

The average operation duration, blood loss and postoperative hospitalization were 242.8 ± 89.9 min, 1581.3 ± 1237.2 ml and 11.9 ± 7.5 days, respectively. Six subjects (37.5 %) suffered instant neurological deterioration. Other complications included cerebrospinal fluid leakage (10 subjects, 62.5 %), new radiculopathy (two subjects), urinary infection, lung infection and pulmonary thromboembolism. Four subjects received extra-thoracic decompression due to the remaining anterior compression in one subject and new emerging compression in other three subjects. Eventually, mean JOA score was elevated from 9.8 ± 2.1 to 13.7 ± 2.7 after this procedure, and the neurological recovery of seven subjects was rated as excellent, four as good, two as fair, three as unchanged or deteriorated. The overall recovery rate was 53.7 %.

CONCLUSION

Combined cervico-thoracic decompression could provide fair neurological outcomes for patients with cervico-thoracic TSS, but it was complicated with high rate of undesirable postoperative events. So, more efforts should be done against its eventful postoperative course before its wide application.

Extensive ossification of the ligamentum flavum treated with triple stage decompression: a case report

BACKGROUND CONTEXT

Concurrent ossification of the ligamentum flavum (OLF) in the cervical, thoracic, and lumbar spine is a rare occurrence often associated with rheumatologic abnormalities. Although the pathology may be asymptomatic and discovered incidentally on routine imaging, compression of the cord and surrounding nerve roots can produce myelopathic or radiculopathic symptoms that are best treated with surgical decompression. There is limited evidence to support the use of single versus multistage decompression for tandem ossification at multiple levels, although several factors including duration of symptoms have been associated with a worse prognosis.

PURPOSE

To describe the presence of extensive symptomatic tandem OLF with concurrent ossification of the posterior longitudinal ligament (PLL) and its treatment using multistage decompression.

STUDY DESIGN

Case report and literature review.

METHODS

The authors describe a case of a 35-year-old woman with OLF extending from the cervical to lumbar spine and tandem ossification of the cervical PLL. Her initial presentation was significant for symptoms consistent with thoracic myelopathy in the absence of radiculopathic findings, and initial imaging also demonstrated disc herniation at L4-L5 and L5-S1.

RESULTS

The patient was first treated with a thoracic laminectomy and fusion from T7 to T11, given her back pain and thoracic myelopathy. Persistence of myelopathic symptoms necessitated further surgical intervention with a posterior cervical decompression and fusion from C3 to T1. Finally, after the appearance of radiculopathic findings, she underwent a microscopic L4-L5 laminectomy with improvements in her symptoms and ambulation.

CONCLUSIONS

Symptomatic OLF in non-East Asian population is a rare occurrence. Its etiology is likely multifactorial, involving both biomechanical and genetic factors. Although early detection and management are necessary, multistage decompression can be an effective intervention for extensive multilevel ossification.

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.

Ossified ligamentum flavum causing spinal cord compression in a patient with acromegaly

Acromegaly is a relatively rare neuroendocrine disorder associated with diffuse hypertrophy of bony and soft tissues due to growth hormone hypersecretion from a pituitary adenoma. Acromegaly can also cause numerous pathological changes in the spine, including degenerative osteoarticular disease, axial arthropathy, spinal stenosis, vertebral fracture and diffuse idiopathic skeletal hyperostosis (Forestier's disease). Ossified ligamentum flavum (OLF) is a rare disorder that often presents as thoracic spinal stenosis, but to our knowledge has never been described in patients with acromegaly. Previously, no link has been established between these two entities. We present, to our knowledge, the first reported case of OLF in a patient with acromegaly who presented with thoracic spinal cord compression. OLF is a potential spinal manifestation of acromegaly and should be considered in the differential diagnosis of spinal stenosis or spinal cord compression in the context of growth hormone hypersecretion.

Single-stage combined decompression for patients with tandem ossification in the cervical and thoracic spine

STUDY DESIGN

Retrospective study of clinical outcomes of single-staged combined cervical and thoracic decompression for patients with tandem ossification (TO).

OBJECTIVE

To describe primary clinical outcomes of this procedure. TO is introduced to described a double ossification lesion of the posterior longitudinal ligament (OPLL) or the ligament flavum (OLF) at the cervical, thoracic and lumbar spine. In clinical practice, cervical OPLL combined with thoracic OPLL or/and OLF are the most common types of TO. However, little is known about the clinical outcomes of surgical treatment and there is no consensus on the optimal treatment to this combined disorder.

METHODS

Between January 2005 and December 2008, 15 patients of this complicated phenomenon were treated by single-staged combined cervical and thoracic decompression in conditions where patients' general condition allowed and individuals agreed on. Surgical intervention, perioperative complications, and clinical outcomes were reviewed in these 15 TO patients who were followed up for more than 2 years (range 2-5 years). Clinical symptoms were evaluated using the JOA scoring system and activity of daily life was evaluated by Nurick classification before surgery, at 6 months postoperatively, and at final follow-up. Patient satisfaction was determined at final follow-up.

RESULTS

The mean blood loss was 1,553.3 ± 735.7 ml (range 700-2,900 ml) and the mean operation time was 280.7 ± 53.6 min (range 220-370 min). The important intraoperative and postoperative complications recorded in medical documents included CSF leakage, hematoma, C5 palsy and neurological deterioration. The JOA score was significantly higher 6 months after surgery (8.1 ± 1.8 points vs. 11.0 ± 1.6 points, p < 0.0001), and there was no significant change between 6 months after surgery and final follow-up (11.0 ± 1.6 points vs. 11.3 ± 2.1, p = 0.5894). The mean Nurick classification significantly improved from grade 3.6 ± 0.7 before surgery to grade 2.5 ± 0.9 at 6 months after surgery (p < 0.001), and well maintained as grade 2.3 ± 1.0 at final follow-up (p = 0.3343). Three patients had satisfaction scores of 3 points, 5 had scores of 2 or 1 point, and 2 had score of 0 point. Pearson correlation analysis showed a significant positive correlation between satisfaction score and JOA score (r = 0.6493, p = 0.0093), and a significant negative correlation between satisfaction score and Nurick classification (r = -0.5941, p = 0.0195). Besides, perioperative complications and progression of tandem ossification which needed revision surgery had significant adverse effect on patients' satisfaction.

CONCLUSIONS

The results showed that single-staged combined decompression could provide comparable clinical outcomes, and patients' satisfaction was significantly related with postoperative neurological function. In addition, satisfaction score could be decreased by perioperative complications and progression of tandem ossification. Thus, this aggressive surgical strategy should be used more carefully with emphasis on preoperative communication with patients.

Ossification of the posterior longitudinal ligament: a review of literature

Ossification of the posterior longitudinal ligament (OPLL) is most commonly found in men, in the elderly, and in Asian patients. The disease can start with mild or no symptoms, but some patients progress slowly to develop symptoms of myelopathy. An accurate diagnosis through the use plain radiograph, computed tomography, and magnetic resonance imaging findings is very important to monitor the development of symptoms and to make decisions regarding a treatment plan. When symptoms are mild and non-progressive, conservative treatments and periodic observations are good enough, but once symptoms of myelopathy are present and neurologic symptoms are progressive, the treatment of choice is surgery to relieve spinal cord compression. Surgical management of OPLL continues to be controversial. Each surgical technique has some advantages and disadvantages, and the choice of operation should be decided carefully with various considerations. The patient's neurological condition, location and extent of pathology, cervical kyphosis, presence or absence of accompanied instability, and the individual surgeon's experience must be an important factors that should be considered before surgery.