Table 1.

Reported cases of unilateral hearing loss due to vascular loop compression in the IAC treated with MVD

Reference	Patient	Presentation	Exam/Imaging	Course	Surgical Findings	Intervention	Outcomes
Shalit and Reichenthal. 1978[21]	44 M	1 year progressive left-sided hearing loss and tinnitus	CT: some enlargement of left internal meatal canal	Left suboccipital craniectomy due to concern for intracanalicular VIII tumor	Constriction of VIII by AICA loop	AICA loop moved medially away from VIII	Complete resolution of hearing loss and tinnitus
Applebaum and Valvassori. 1984[19]	37 F	5 years left-sided progressive hearing loss, tinnitus, and vertigo	Pneumo-CT: left AICA entering IAC and looping around VIII	Left suboccipital craniectomy	AICA entering IAC and compressing VIII	Separation of AICA and VIII with Teflon felt	NR
Roland et al. 1995[39]	50 M	Left-sided mild hearing loss and severe tinnitus	ABR: increased I-III interpeak interval on left compared to right	Left suboccipital craniotomy	VIII compressed by PICA	Autologous muscle interposed between PICA and VIII	Complete relief of tinnitus and improved hearing
Roland et al. 1995[39]	55 M	Right-sided mild hearing loss and severe tinnitus	Absent stapedius reflexes in right ear, audiometric evaluation showed high-frequency hearing loss on right side	Right suboccipital craniotomy	VIII compressed by AICA	Autologous muscle interposed between AICA and VIII	Marked improvement of tinnitus and stapedial reflexes, returned to normal 1 year postoperatively
Herzog et al. 1997[22]	63 M	1.5 years left-sided hearing loss and vertigo	MRI: enhancement in left IAC	Worsening hearing loss and disequilibrium with new hemifacial spasm over 6 weeks à translabyrinthe approach to IAC	AICA between VII and VIII	Displacement of AICA from VII using Teflon pledget	Complete resolution of disequilibrium and hemifacial spasm
Herzog et al. 1997[22]	63 M	1 year right-sided hearing loss with sudden complete hearing loss and vertigo	MRI: bulbous enhancing lesion in IAC	Translabyrinthe approach to IAC	AICA coursing laterally though IAC, posterior to VII and VIII	Elevated AICA away from VII and VIII	Dizziness subsided over 4 weeks, facial nerve function gradually improved over 6 months
Okamura et al. 2000[29]	39 F	10 years intermittient vertigo with right-sided tinnitus and hearing loss, 40 months phonophobia	Abnormal ABR’s	Surgical intervention	AICA compressing cochlear nerve, PICA attached to inferior vestibular third	AICA loop displaced medially, PICA displaced with Teflon-cushion	Complete resolution of high-pitched tinnitus (low-pitched tinnitus continued), phonophobia, and vertigo, improvement in hearing
Scoleri et al. 2001[40]	33 M	Several years vertigo, fluctuating sensorineural hearing loss, tinnitus, and aural fullness, diagnosed with Meriere’s disease	Audiometric testing showed sensorineural hearing loss in left ear, MRI: normal	Elected for vestibular nerve section procedure via retromastoid approach	Main trunk of AICA bisected vestibulocochlear nerve	Vestibular nerve divided and 6 mm segment removed, MVD of cochlear division with Teflon sponge between it and AICA	Resolution of vertigo but continued progressive hearing loss 4 years postoperatively
Sakas et al. 2007[41]	52 F	6 years right-sided otalgia, hearing loss, tinnitus, and vertigo	MRI: AICA curved into IAC and compressed VII and VIII	Retromastoid craniotomy	AICA compressing VII and VIII	AICA loop mobilized and Teflon narrow band placed between it and VII/VIII	Complete resolution of otalgia after 6 months, improvement in hearing, tinnitus, and vertigo

Abbreviations: CT = computed tomography, MRI = magnetic resonance imaging, MRA = magnetic resonance angiography, MVD = microvascular decompression, ABR = auditory brainstem response, AICA = anterior inferior cerebellar artery, PICA = posterior inferior cerebellar artery, CPA = cerebellopontine angle, IAC = internal auditory canal, VII = facial nerve, VIII = vestibuolocochlear nerve, NR = not reported