Axial Back Pain Secondary to Ligamentum Flavum Ossification in a Patient with Hypoparathyroidism: A Rare Case Report

Abstract

The ligamentum flavum is a structure that connects adjacent laminae and plays a role in maintaining upright posture. Hypoparathyroidism can rarely cause ligamentum flavum ossification (LFO). LFO can cause symptoms due to spinal cord compression. A 48-year-old man was evaluated for complaints of widespread back pain, a burning sensation, and numbness in the lower extremities. Imaging revealed spinal stenosis at the T10-T11 level due to LFO. Following facet joint block and duloxetine treatment, the VAS score decreased from 8 to 3. Early diagnosis and appropriate treatment of LFO in patients with hypoparathyroidism are critical for symptom control and functional recovery.

Hypoparathyroidism is a rare endocrine disorder characterized by insufficient secretion of parathyroid hormone, leading to low calcium and high phosphate levels in the blood, and may cause calcifications in soft tissues, especially ligamentous structures in the spine. In particular, ligament ossification may progress, leading to myelopathy, pain, and neurological deficits.^[1] The ligamentum flavum connects adjacent laminae and helps maintain upright posture. The ligamentum flavum is elastic, but when ossification occurs, spinal flexibility decreases, ultimately leading to compression of the spinal cord or nerve roots.^[2] It is most commonly seen in the thoracic spine and may be associated with endocrinological diseases such as hypoparathyroidism.^[3] Although this condition is well known, ligamentum flavum ossification (LFO) due to hypoparathyroidism is a rare clinical entity. In the present case, we aimed to describe a patient with hypoparathyroidism who developed LFO at the thoracic level, causing neuropathic pain and functional impairment.

Case Report

A 48-year-old man presented to the internal medicine outpatient clinic with complaints of progressively worsening back pain and excessive sweating over the previous five months. Laboratory tests revealed hypocalcemia, and further evaluation led to a diagnosis of hypoparathyroidism (Table 1). The patient’s pain was sharp and stabbing and radiated to the back. The patient also described burning, numbness, and tingling sensations below the knee. Neurological evaluation revealed no sensory or motor deficits. Straight leg raise and femoral stretch tests were negative, and deep tendon reflexes were normoactive. Because no neurological findings warranting electrophysiological examination were detected during the clinical evaluation, electromyography (EMG) was not planned. His visual analog scale (VAS) score at presentation was 8. A thoracic spine computed tomography (CT) scan revealed ossification of the ligamentum flavum at the T10-T11 level (Fig. 1), consistent with the patient’s symptoms. A facet joint injection was performed using a mixture of 4 mg dexamethasone and 1 cc of 2% lidocaine under ultrasound guidance. The initial facet joint blockade provided minimal symptomatic relief. He was subsequently started on 60 mg duloxetine, and his VAS score decreased to 3. Pain scores remained low during the 6-month follow-up. Written informed consent was obtained from the patient for the publication of this case report and any accompanying images.

Figure 1.

Calcification of the ligamentum flavum at the thoracic level 10-11 is shown with white and black arrows.

Discussion

Ligamentum flavum ossification is a progressive condition that can cause serious morbidity due to spinal cord or nerve root compression.^[2] Although its etiology is multifactorial, metabolic diseases such as hypoparathyroidism may play an important role in its pathogenesis.^[2,3] Chronic hypocalcemia and hyperphosphatemia in hypoparathyroidism can cause dystrophic calcifications, including those involving the ligamentum flavum, leading to ossification and subsequent neurological complications.^[4] In the present case, thoracic LFO developed in a patient with hypoparathyroidism, causing axial pain and neurological symptoms, which were controlled with interventional and medical treatment.

Hypoparathyroidism results in decreased secretion of parathyroid hormone, leading to hypocalcemia and hyperphosphatemia. This electrolyte imbalance promotes ectopic calcification in soft tissues, including connective tissue structures such as the ligamentum flavum. Sohail et al.^[5] reported a case of LFO involving the cervical and thoracic regions due to primary hypoparathyroidism. In this case, complete neurological recovery was achieved after surgical decompression. Ahn et al.^[2] stated that cauda equina syndrome may develop in cases of severe compression due to ligamentum flavum ossification and that surgery is the only treatment option. Hur et al.^[4] showed that surgery was an effective treatment, especially in the early stages, in 26 patients who developed myelopathy. In the present case, the patient with axial pain experienced relief following a facet joint injection. The patient’s symptoms were consistent with neuropathic pain resulting from ligamentous compression. Medical treatment with duloxetine provided partial symptomatic relief and was beneficial in treating the neuropathic pain associated with LFO. However, in cases with advanced neurological deficits or persistent pain, surgical decompression is the most effective treatment option.^[2,4]

This case highlights the need to consider endocrinological and metabolic disorders in patients presenting with unexplained spinal ossification.

Conclusion

Ligamentum flavum ossification secondary to hypoparathyroidism is a rare but significant cause of back pain and neurological symptoms. A high level of awareness is essential for early diagnosis in patients with metabolic risk factors. Pharmacological and interventional treatments can alleviate symptoms, but surgical decompression may be necessary in progressive cases.

Disclosures

Ethics Approval

This is a single case report, and therefore ethics committee approval was not required in accordance with institutional policies.

Informed consent

Written informed consent was obtained from the patient for the publication of this case report and any accompanying images.

Conflict of Interest

The authors declare that there is no conflict of interest.

Financial Disclosure

This study received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.

Use of AI for Writing Assistance

The authors declare that no generative artificial intelligence or AI-assisted tools were used in the preparation or editing of this manuscript.

Authorship Contributions

Concept – H.G., R.S., G.E.; Design – R.S., T.S., Y.A., H.K.; Supervision – T.S. Y.A.; Fundings – T.S., Y.A.; Materials − R.S., H.G., T.S.; Data collection &/or processing – H.G., G.E., H.K.; Analysis and/or interpretation – R.S., T.S., H.K.; Literature search – H.G., H.K.; Writing – H.G., R.S., G.E.; Critical review – R.S., T.S., Y.A.

Peer-review

Externally peer-reviewed.