Coexisting spinal enthesopathy syndromes – A rare finding

Kavin Devani; Anup Purandare; Ravi Wankhade; Prakash Palave; Archana Sharma; Batuk Diyora

doi:10.4103/joss.joss_10_22

CASE REPORT

Year : 2022 | Volume : 9 | Issue : 3 | Page : 173-177

Coexisting spinal enthesopathy syndromes – A rare finding

Kavin Devani¹, Anup Purandare¹, Ravi Wankhade¹, Prakash Palave¹, Archana Sharma², Batuk Diyora¹
¹ Department of Neurosurgery, LTMG Hospital, Mumbai, Maharashtra, India
² Department of Anaesthesia, LTMMC and LTMG Hospital, Mumbai, Maharashtra, India

Date of Submission	23-Feb-2022
Date of Acceptance	19-Apr-2022
Date of Web Publication	13-Sep-2022

Correspondence Address:
Batuk Diyora
Department of Neurosurgery, Second Floor, College Building, LTMG Hospital, Sion, Mumbai - 400 022, Maharashtra
India

Source of Support: None, Conflict of Interest: None

DOI: 10.4103/joss.joss_10_22

Abstract

Ossification of the posterior longitudinal ligament (OPLL) is an uncommon spinal pathology. It can compress the spinal cord and result in a significant neurological deficit. Ossification of the ligamentum flavum (OLF) is a condition characterized by the formation of ectopic bone in the ligamentum flavum resulting in neurological impairment due to spinal cord compression. The coexistence of both these conditions is not frequently encountered. We present a unique case of a young male patient. He presented with weakness in both lower limbs, gait ataxia, and urinary symptoms due to spinal cord compression at lower dorsal and cervical levels due to OLF and OPLL, respectively.

Keywords: Ossification of ligamentum flavum, ossification of the posterior longitudinal ligament, spinal enthesopathy syndromes

How to cite this article:
Devani K, Purandare A, Wankhade R, Palave P, Sharma A, Diyora B. Coexisting spinal enthesopathy syndromes – A rare finding. J Spinal Surg 2022;9:173-7

How to cite this URL:
Devani K, Purandare A, Wankhade R, Palave P, Sharma A, Diyora B. Coexisting spinal enthesopathy syndromes – A rare finding. J Spinal Surg [serial online] 2022 [cited 2023 Apr 2];9:173-7. Available from: http://www.jossworld.org/text.asp?2022/9/3/173/356018

Introduction

”Enthesis” denotes the attachment of the bone with muscle, tendon, or ligament. They are of two varieties: fibrous and fibrocartilaginous. Any condition which leads to their affection or involvement is called enthesopathies. There are three types of known spinal enthesopathy syndromes reported in the literature: ossification of the posterior longitudinal ligament (OPLL), ossification of the anterior longitudinal ligament (OALL), and ossification of other vertebral arch ligaments with other extraspinal ligaments, which also includes the ligamentum flavum.^[1] Often, they coexist. We present a patient with multiple such enthesopathy involving the thoracic and the cervical spine.

Case Report

A 40-year-old male patient presented with dull and progressive lower backache for a year with gradually progressive difficulty in walking. It was accompanied by a burning sensation in both lower limbs. He had developed urinary retention for the past 3 weeks, for which he was catheterized. On examination, we observed a well-nourished man with intact higher mental functions. His neurological examination revealed hypertonia in both lower limbs. He exhibited muscle weakness Grade 3/5 in both lower limbs at all joints with sensory deficits of pain, touch, and temperature senses below D12 on both sides. Bilateral knee and ankle jerks were brisk, and bilateral extensor plantar response was observed. His joint position sense was affected bilaterally. The neurology of both upper limbs was unaffected. His cervical spine roentgenogram was suggestive of degenerative changes in the cervical region as well as the thoracic and lumbar region.

His magnetic resonance imaging (MRI) cervical spine demonstrated compression of the spinal cord from anteriorly at the level of C3 to C6 vertebral level [Figure 1]a, and his MRI thoracic spine showed spinal cord compression from posteriorly at D10 to D11 disk level due to ossification of ligamentum flavum (OLF) [Figure 1]b and [Figure 1]c. It resulted in severe narrowing of the canal, with its diameter being 4.8 mm. His computed tomography (CT) scan cervical and lumbar spine revealed OPLL from C3 to C6 vertebral level and OALL from L2 to L5 level [Figure 2]a and [Figure 2]b. His CT scan of the thoracic spine showed calcified ligamentum flavum resulting in the narrow spinal canal at the level of D10‒D11 disk level [Figure 2]c and [Figure 2]d.

Figure 1: MRI of the cervical spine sagittal T2-weighted image showing compression of the spinal cord from anteriorly at the level of C3 to C6 vertebral level (a). MRI of the thoracic spine sagittal (b) and axial (c) T2-weighted image showing spinal cord compression from posteriorly at D10 to D11 disk level due to calcified ligamentum flavum. MRI: Magnetic resonance imaging

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Figure 2: CT scan of the cervical spine bone window sagittal view (a) showing ossification of the posterior longitudinal ligament from C3 to C6 vertebral level and lumbar spine bone window sagittal view (b) OALL from L2 to L5 level. CT scan of the thoracic bone window sagittal view (c) and axial view (d) showing calcified ligamentum flavum resulting in the narrow spinal canal. CT: Computed tomography. OALL: Ossification of the anterior longitudinal ligament

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After clinico-radiological correlation, his symptoms were attributed to the thoracic spinal cord compression. The cervical pathology was an innocent bystander as far as his symptomatology profile was considered. He was subjected to decompression at D10 and D11 levels by performing the laminectomy at these levels. Bony elements were hyperostotic and nearly avascular. The ossified and hypertrophied ligamentum flavum was firmly adherent to the dura and was not separable. Due to persisting compression effect on the spinal cord, the dura was opened all around the lesion, and the lesion was excised along with the dura. The canal was drilled all around, and the spinal cord was completely freed. Dura was closed with tensor fascia lata graft and reinforced with tissue glue. The postoperative course was uneventful. Significant improvement in his power to Grade 5/5 was achieved in both lower limbs over 2 weeks. His sensory symptoms also showed remarkable improvement. His gait improved significantly. His urinary complaints had resolved, and he was discharged on the 5^th postoperative day. Histopathological examination of the specimen revealed evidence of bony elements. The patient was unwilling to undergo any surgical intervention for his cervical pathology of OPLL. Follow-up thoracic spine CT scan revealed complete decompression of the spinal canal [Figure 3]a and [Figure 3]b.

Figure 3: Postoperative CT scan of the thoracic spine bone window sagittal view (a) and axial view (b) showing decompressed spinal canal (b). CT: Computed tomography

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Discussion

Spinal enthesopathy is a condition characterized by the affection of the paraspinal and extraaxial ligaments. They are of three varieties, namely OPLL, OALL, and ossification of other vertebral arch ligaments with other extraspinal ligaments, including the ligamentum flavum.^[1] Ligamentum flavum is yellowish-white paired ligaments that connect the adjacent laminae of the vertebral column. They are found extending from C1 to S1.^[2],[3] They originate on either side from the articular processes on either side of the nerve root, extending posteriorly along the laminae to the midline. In the midline, they fuse partially with the contralateral ligament.^[4] Their vertical attachment is from the superior lamina's anteroinferior surface to the inferior lamina's posterosuperior surface.^[4],[5] It is composed of longitudinal elastic tissue. It functions as an elastic band, allowing the spinal column to resume a neutral position after flexion and extension.^[5],[6] OLF, causing thoracic level spinal canal stenosis, leading to the stenosis to thoracic myelopathy, is rare. OLF usually affects the thoracic and lumbar regions. An association with diffuse idiopathic skeletal hyperostosis, diabetes mellitus, increased bone density, heavy manual labor, and higher body mass index values has been established.^[6] Genetic association with COL6A1 and COL11A2 genes mutation has also been found to cause this disease.^[7] The genes responsible for Notch,^[8] Indian hedgehog,^[9] beta-catenin,^[10] p38, and Erk1^[11] signaling pathways are postulated to be responsible for its causation. The normal fibrous structure is replaced by the ectopic lamellar bone, formed through endochondral ossification of the vascularized fibrocartilaginous tissue starting at the densely adherent ligamentous-osseous junction, extending along the ventral aspect of the ligament.^[12] Degenerative wear and tear and external triggers such as biomechanical stress are postulated to cause changes.^[13] The normal fibrous structure is replaced by the cells rich in fibrocollagenous tissue. Cells were also found to have an increased expression of Type 2 collagen – a marker of chondrocyte and osteocalcin – a marker of osteoblasts.^[2] Histologically, clustering of abnormal fibrocartilage or fibrocartilaginous cells with neovascularization heralds the development of this condition.^[7] OLF results in canal stenosis, which leads to clinical symptoms. It usually starts with the sensory symptoms, and motor weakness follows. The ones in the lumbar region can present with lumbar radiculopathy or cauda equina syndrome.^[6],[13]

OLF starts laterally and progresses medially. This condition is subdivided into five types based on their extent and location of ossification: lateral, extended, enlarged, fused, and tuberous.^[14] In the lateral or Type 1 type, the ossification is found laterally at the origin of the ligamentum flavum near the articular process. The extended type or Type 2 variety presents with the extension of ossification from the articular process to the interlaminar portion of the ligamentum flavum. The enlarged type or Type 3 is when the ossification protrudes into the canal posterolaterally but remains unfused in the midline. The fused variety or Type 4 consists of bilateral ossified ligaments fused in the midline with a groove at the fusion in the midline. Type 5 or the tuberous type is when the ossified ligament forms a tuberous mass posteriorly in the midline, which protrudes into the spinal canal. Plain radiography is not very sensitive to diagnose this condition.^[6],[14] CT scan and the sagittal bone window are the gold standard investigation to diagnose them. Dural ossification should be ruled out. As pointed out by Muthukumar, two reliable signs are the tram-track sign, which is the hyperdense bony excrescence with a hypodense center, and the comma sign, which is the ossification of the one half of the circumference of the dura.^[15] MRI is a useful adjunctive investigation to identify the spinal cord compression and find out other coexisting compressive lesions or myelopathy. A thorough screening of the entire spinal axis is warranted before any surgical intervention is planned.^[6]

The management of this condition usually comprises decompression surgery with or without fusion procedure.^[12] The ossified ligament is firmly adherent to the dura; hence, adequate precaution should be taken to excise it. One should aim for maximum safe resection instead of its complete excision. Results associated with its surgical intervention are often promising unless there is a hyperintense signal in the MRI preoperatively. Dural ossification increases the chances of complications such as cerebrospinal fluid leakage and meningitis. Other complications include weakness to varying extent, epidural hematoma, and delayed kyphosis.^[16] Single level, unilateral pathology, and shorter duration of symptoms are associated with favorable outcomes.^[17],[18]

A coexisting enthesopathy, OPLL is often encountered while scanning the entire spinal axis. OPLL is characterized by heterotopic ossification of cervical or thoracic posterior longitudinal ligament, which results in varying degrees of neurological compromise.^[19] This condition commonly affects the male population. Patients with this condition present with numbness, axial neck pain, and radicular pain and can cause compressive cervical myelopathy. CT Imaging, especially the sagittal bony window, is the gold standard investigation for its diagnosis. Often, a plain radiograph is not valuable to reach the diagnosis. MRI is done to determine the degree of compression and other pathologies leading to cervical myelopathy. Management comprises either anterior or posterior approach. The anterior approach includes the anterior cervical discectomy or anterior corpectomy, whereas the posterior approach includes laminectomy with or without fusion procedures or laminoplasty depending on the patient's profile.^[19] Thus, one should always screen the entire spinal axis as more than one coexisting lesion may be there. Not only should the most significant culprit be identified but also the patients should be adequately counseled about the coexisting pathology, and that should also be treated timely. In one of the series published by Park et al., 6 out of 23 patients had coexisting OPLL with OLF.^[20] In another series published by Kawaguchi et al., 64.6% of patients had ossifications at cervical and thoracic levels.^[21] Thus, all patients with ossification at any level should be adequately screened at other levels and treated accordingly. It is being exceedingly observed that dynamic spinal imaging plays a crucial role in the diagnosis of spinal cord myelopathy. It is complimentary to the static MRI performed for the routine evaluation of the spinal pathologies, as it takes into account the changes in the canal diameter with flexion and extension motion. It can thus reveal additional pathologies and instability and lead to their timely intervention.^[22]

Conclusion

OLF and OPLL are commonly encountered pathologies. However, encountering them in unison at different levels is not frequently encountered. Thus one should screen the entire spine when any of these pathologies is encountered. The pathology leading to significant neurological deficit should be treated first, followed by the bystander pathology.

Declaration of patient consent

The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient(s) has/have given his/her/their consent for his/her/their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity, but anonymity cannot be guaranteed.

Financial support and sponsorship

Nil.

Conflicts of interest

There are no conflicts of interest.

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