Introduction: Microvascular decompression (MVD) is a surgical treatment for trigeminal neuralgia or hemifacial spasm, in which an aberrant vascular loop compressing the root entry zone (REZ) is identified and the nerve is decompressed using polytetrafluoroethylene (Teflon). We report the first case of a Teflon granuloma after MVD for hemifacial spasm, presenting with a large, compressive, contrast-enhancing mass causing vertigo, nystagmus, facial weakness, deafness, and trigeminal and glossopharyngeal neuralgias.

Methods: Case report and review of the literature

Results: A 75-year-old woman presented with worsening hemifacial spasm, incompletely managed by botulinum toxin and clonazepam. She underwent microvascular decompression using Teflon pledgets, and awoke with complete resolution and no deficits. One year later, she experienced acute ipsilateral hearing loss; MRI identified a small area of enhancement at the surgical site, which was managed expectantly. Four years later, she developed episodes of ipsilateral V1-3 and glossopharyngeal pain, vertigo, and ipsilateral facial weakness (House-Brackmann III). MRI demonstrated a 1.9cm enhancing cerebellopontine angle mass with a dural tail and no internal auditory canal extension. Exploration revealed a densely adherent mass involving the facial and vestibulocochlear nerves; gross total resection was achieved, but the patient awoke with House-Brackmann V facial paralysis. Literature review identified five preceding reports, documenting 10 Teflon granulomas after MVD for trigeminal neuralgia.

Conclusions: Teflon granuloma is a rare MVD complication, with an incidence of 1.1-7.3%. Ours is the second report of Teflon granuloma after treatment of hemifacial spasm, and the first such lesion to present with multiple new cranial neuropathies—likely attributable to its uniquely large size, in contrast to typical presentation of a small mass causing recurrent trigeminal pain. The underlying pathophysiology is poorly understood—no risk factors have been identified. Outcomes after repeat surgery are variable; symptomatic relief is typically achieved; however, excessive scarring is common, and resection of large granulomas risks cranial nerve injury.

Patient Care: Our report characterizes a unique presentation of a rare but important complication of a common neurosurgical procedure, synthesizes the findings of related reports, emphasizes the importance of thorough patient counseling, and highlights a potential area for future research regarding identification of risk factors and understanding of underlying pathophysiology.

Learning Objectives: 1.) Discuss the pathophysiology of hemifacial spasm and trigeminal neuralgia, and the role of microvascular decompression with Teflon in their treatment algorithms 2.) Identify clinical history and imaging findings consistent with a possible Teflon granuloma 3.) Discuss the risks and benefits of surgical intervention for symptomatic Teflon granuloma

References: Capelle (2010) Treatment of recurrent trigeminal neuralgia due to Teflon granuloma Chen (1999) Teflon Granuloma after microvascular decompression for trigeminal neuralgia Megerian (1995) Teflon granuloma presenting as an enlarging, gadolinium enhancing, posterior fossa mass with progressive hearing loss following microvascular decompression Premsagar (1997) Teflon-induced granuloma following treatment of trigeminal neuralgia by microvascular decompression