Calcification of ligamentum flavum (CLF) is a degenerative spinal disease in which calcium crystals deposit in the ligamentum flavum. The CLF may cause spinal cord compression, and the patient may need decompressive surgery. However, CLF can spontaneously regress with some medications as well as no treatment. Here, the authors reported a case in which small CLF remaining after cervical decompression surgery markedly enlarged during the follow-up period and spontaneously regressed after pregabalin administration. Therefore, pregabalin might be involved in the spontaneous regression of CLF.
A 66-year-old female complaining of right upper limb pain and numbness was diagnosed with CLF at C5/6 and C6/7 by computed tomography (CT) and magnetic resonance imaging (MRI). The symptoms improved after removal of the CLF at C5/6 with C5 laminectomy and C4, C6 laminoplasty. Postoperative CT showed small residual CLF at C6/7. Six years after surgery, she suffered pain and numbness in her right arm. Her cervical MRI showed a marked increase of CLF at C6/7. The pain disappeared after the administration of pregabalin. Six months later, a marked reduction of CLF was observed on MRI.
It has been reported that the administration of cimetidine or etidronate resulted in the regression of CLF. Cimetidine affects calcium metabolism via parathyroid hormone (PTH), and etidronate has an inhibitory effect on calcification. It was reported that the serum PTH was markedly reduced in a uremic patient after the administration of pregabalin. The efficacy of pregabalin was also reported for a case with refractory paroxysmal kinesigenic choreoathetosis whose parathyroid glands were removed. It is presumed that pregabalin was involved in calcification regression via PTH metabolism in this case.