Recurrence of hypertrophic spinal pachymeningitis. Report of two cases and review of the literature.

Hypertrophic spinal pachymeningitis (HSP) is a comparatively rare disease characterized by hypertrophic inflammation of the dura mater and clinical symptoms that progress from local pain to myelopathy. The authors report two cases of recurrent HSP and review the English- and Japanese-language literature focusing on the recurrence of HSP. In the first case, a man who presented at 67 years of age with lower-extremity numbness, gait disturbance, and bladder dysfunction experienced two recurrences of HSP during the 11 years of follow up after his initial laminectomy. Both recurrences were successfully treated with laminoplasty and duraplasty. Three years after his last surgical procedure, he was still able to walk with the aid of a walker. In the second case, a man who presented at 62 years of age with lower-extremity numbness and gait disturbance was initially treated successfully with steroid pulse therapy. Approximately 8 months after his initial presentation, his symptoms recurred. He underwent laminoplasty and duraplasty. At the 2.5-year follow-up examination, he had only mild neurological deficits and was still able to walk unaided. To explore possible causes of recurrence, the authors searched the English- and Japanese-language literature for cases of HSP. Of the 96 cases identified, 11 were recurrent. Data on the presence or absence of inflammatory signs were available for 84 patients. A chi-square analysis revealed a significantly increased rate of recurrence for patients who had at least one positive inflammatory sign before surgery (six [20%] recurrent cases of 30) compared with those who had no positive inflammatory signs before surgery (two [3.7%] recurrent cases of 54) (p < 0.05). The authors conclude that HSP recurrence occurs because of active inflammation of the dura before surgery and the influence of chronic inflammation, including residual arachnoiditis.