MR imaging of venous malformations: sciatic nerve infiltration patterns and involved muscle groups

Area of Science:

• Radiology
• Neurology
• Vascular Surgery

Background:

• Venous malformations (VMs) are congenital vascular anomalies.
• Sciatic nerve involvement by VMs can lead to significant morbidity.
• Understanding the patterns of VM infiltration is crucial for diagnosis and management.

Purpose of the Study:

• To establish an MRI-based framework for evaluating sciatic nerve infiltration by VMs.
• To determine the frequency of nerve infiltration patterns and associated muscle involvement.
• To correlate imaging findings with patients' quality of life, specifically pain and motion restriction.

Main Methods:

• Retrospective cross-sectional study of 378 patients with vascular malformations.
• Analysis of pelvic and lower limb MRI scans.
• Evaluation of pain and motion restriction using questionnaires.
• Detailed documentation of intraneural infiltration patterns and muscle involvement.

Main Results:

• Sciatic nerve infiltration by VM occurred in 7.7% of patients.
• VMs in surrounding gluteal or hamstring muscles were present in 100% of infiltrated cases.
• Infiltrated nerves showed enlargement and T2-hyperintensity on MRI.
• Enlarged nerve cross-sectional areas correlated with elevated pain levels.
• Observed infiltration patterns: subepineurial (52.2%), subparaneurial (26.1%), and combined (21.7%).

Conclusions:

• MRI provides a framework for assessing sciatic nerve and muscle involvement by VMs.
• VMs in the gluteal and hamstring muscles warrant careful radiologic investigation of the sciatic nerve.
• Identifying specific infiltration patterns may aid in understanding clinical manifestations and guiding treatment.