Ossification of Ligamentum Flavum

Vinod NaneriaGirish Yeotikar

Arjun WadhwaniChoithram Hospital & Research Centre,

Indore, India

Why this case?

• Ossification of Ligamentum Flavum is a unusual cause of neurogenic claudication in early stage of the disease.

• It may be the only presenting symptom.• First reported by Polgar in 1920 on plain lateral x-ray of

spine.• Thoracic myelopathy due to ossified LF was described in

1964 by Yamaguchi and Isuruni.• Myelopathy & radiculopathy in advance disease.• Coexist with Ossification of Dura.• Coexist with Lumbar Canal Stenosis.

Reading MRI Critically

• All MRI done for any segment of spine starts with cervical spine.

• This is done for exact counting of level of vertebrae.

• A record of lumberization/sacralization.• Last floating Rib.• Level of disc pathology.

Reading MRI Critically

• Although MRI of whole spine is done, reporting is done for the segment of interest; Lumbar, Dorsal, Cervical or SI joints.

• Incidental findings are about 8%.• Many incidental findings in many part of the

spine goes unreported inadvertently .• These incidental findings are vertebral

Hemangioma, Tarlov cyst, fibrolipoma, synovial cyst, and sacral meningocele, some times OLF.

Case History

• A 45 Male, C/o vague backache with radiating pain in both gluteal regions increased by standing and walking.

• Typical neurogenic claudication with varying distances.

• There was no obvious neurological or vascular deficit.

• Planters were down going.

Investigations

• Routine investigations were normal.• X-ray dorso – lumbar spine reported normal.• MRI – classical picture of ossification of

ligamentum flavum.• Axial CT confirms the diagnosis.

Case Two

• A 60 yrs. Male• Gradually increasing paraperesis.• Spastic &weak both lower limbs.• Intact bladder bowel control.

OLF

• Ossification of the ligamentum flavum (OLF) is a disease of ectopic bone formation within the ligamentum flavum, which may result in mass effect and neurological compromise.

• The low thoracic region is the most common region of occurrence, and this is followed by the cervical, then lumbar spine.

• 64% at D10 - D11, 21% at D11 - D12.• The prevalence of OLF is higher in the Japanese (20% above

the age of 65 years) compared with other nationalities and has a male preponderance.

• Commonly associated with dural ossification.

Etiology

• Unknown in most of the cases.• Diffuse idiopathic skeletal hyperostosis (DISH), • Ankylosing spondylosis, • Hemochromatosis, • Fluorosis, • Calcium pyrophosphate dihydrate deposition

disease (CPPD),• Trauma.

Patho - physiology

• Initially the ligament get hypertrophied, and calcify before it get ossified.

• The process of ossification starts at the base of the ligament with enchondral ossification of the vascularised fibrocartilaginous tissues. It starts from capsular side and gradually spread anteriorly and medially compressing the spinal card from posterio-lateral sides.

Clinically

• Two types of presentations:– Most commonly present as gradual onset of

myelopathy with slow deterioration in neurological status.

– Occasionaly present as acute paraplegia following minor trauma.

Diagnosis

• OLF should be included in causes of thoracic paraplegia.

• X-rays are not very classical.• MRI – T2 weighted seggital plane shows

indentation on the thoracic card from behind• CT – Axial plane shows typical ossification of

OLF.

Radiological signs of DO

• The radiologic signs of dural ossification (DO)as depicted in the bone windows of CT were of 2 types:

• The "tram track sign," where there was a hyperdense bony excrescence with a hypodense center.

• The "comma sign," where there was evidence of ossification of one-half of the circumference of the duramater.

• Incidence of CSF leak is very high in cases of DO, following surgical excision of OLF.

Types• Type I, is located only laterally at the origin of the ligamentum

flavum at the articular processes. • Type II, The extended type, extends from the lateral origin of the

ligamentum flavum to the interlaminar portion of the ligamentum flavum.,

• Type III, The enlarged type protrudes into the canal posterolaterally but is not fused in the midline.

• Type IV, The fused type, consists of bilateral ossified ligaments that are fused at the midline with a groove at the fusion in midline.

• Type V, the tuberous type, occurs when the fused ossified ligamentum flavum forms a “tuberous” mass posteriorly in the midline, which protrudes into the spinal canal.

Treatment

• Decompressive Laminectomy.• Laminoplasty, retaining posterior elements.• Laminectomy and fusion to prevent increase in kyphotic

deformity.• Complications are high when it is associated with

ossification of dura.• Commonest complication is CSF leak due to associated

dural calcification.• This can cause meningitis, delayed wound healing,

incomplete neurological recovery or deterioration in neurological status.

Review literature

• Omojola MF, Cardosa ER, Fox AJ et al : Thoracic myelopathy secondary to ossified ligamentum flavum. J Neurosurg 1982; 56: 448-450.

• Miyasaka K. Kiyoshi, K. Ito T et al : Ossification of spinal ligaments causing thoracic radiculomyelopathy. Radiology 1982; 143: 463-468.

• Jayakumar PN, Devi BI, Bhat DI, Das BS. Thoracic cord compression due to ossified hypertrophied ligamentum flavum. Neurol India. 2002 Sep;50(3):286-9.

• Virani M, Parekh Harshed, Palande Deepak : Dorsal canal stenosis - A rare cause of compressive dorsal myelopathy -Report of three cases. Neurol India 1990; 38: 305-308.

• Mitra SR, Gurjan SG, Mitra KR: Degenerative disease of the thoracic spine in Central India. Spinal Cord 34:333-337, 1996.

• Sushil P, Anant K: Ossified-calcified ligamentum flavum causing dorsal cord compression with computed tomography-magnetic resonance imaging features. Surg Neurol 41:441-442, 1994.

• Stollman A, Pinto R, Benjamin V et al : Radiological imaging of symptomatic ligamentum flavum thickening with and without ossification. AJNR 1987; 8: 991-994.

• Yazmaguchi M, Tamagake S, Fujita S : A case of the ossification of the ligamentum flavum with spinal cord tumour symptoms (in Japanese) Seikeigeka (Orthop Surg) 1960; 11: 951-956.

DISCLAIMER Information contained and transmitted by this presentation is

based on personal experience and collection of cases at Choithram Hospital & Research centre, Indore, India, during last 32 years. It is intended for use only by the students of orthopaedic surgery. Views and opinion expressed in this presentation are personal opinion. Depending upon the x-rays and clinical presentations viewers can make their own opinion. For any confusion please contact the sole author for clarification. Every body is allowed to copy or download and use the material best suited to him. The author is not responsible for any controversies arise out of this presentation. For any correction or suggestion please contact naneria@yahoo.com