The Intraosseous Subarcuate Loop of Anterior Inferior Cerebellar Artery: Anatomic Management Guide, Single-Center MRI...

Area of Science:

• Neurosurgery
• Vascular Anatomy
• Radiology

Background:

• The intraosseous subarcuate loop (SL) is an anatomical variant where the anterior inferior cerebellar artery (AICA) loops within the petrous bone's subarcuate fossa.
• This variant is significant for cerebellopontine angle (CPA) surgery planning, but its prevalence and management data are inconsistent in literature.
• Accurate identification is crucial for preventing vascular injury during surgical interventions in the CPA region.

Purpose of the Study:

• To assess the prevalence of the intraosseous AICA's SL using MRI in a single-center cohort.
• To compare the observed prevalence with existing literature data.
• To provide a detailed intraoperative guide for mobilizing the intraosseous AICA's SL through cadaveric dissection.

Main Methods:

• Retrospective review of 258 CPA MRI scans (516 sides) to identify intraosseous vascular loops.
• Multiplanar reconstruction of MRI data to evaluate the frequency of the intraosseous loop.
• Scoping review of published literature on intraosseous AICA's SL prevalence and detailed cadaveric dissection for surgical technique.

Main Results:

• The intraosseous AICA's SL was identified in 0.8% of the evaluated 516 CPA sides (4 cases).
• Literature review revealed prevalence rates ranging from 0.2% to 1.6% across various radiological modalities.
• Cadaveric dissection detailed a step-by-step mobilization technique, emphasizing dural cuff preservation to prevent vascular injury.

Conclusions:

• The intraosseous AICA's SL is an uncommon but significant anatomical variation detectable by MRI.
• This variant presents an increased risk during CPA surgery, necessitating careful identification and management.
• Proper surgical mobilization techniques are essential for safe vascular preservation in cases involving the intraosseous AICA's SL.