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Updated: Dec 1, 2025
A Unified Methodological Framework for Vestibular Schwannoma Research
Published on: June 20, 2017
MRI Monitoring of Residual Vestibular Schwannomas: Modeling and Predictors of Growth
Maxime Fieux1, Sandra Zaouche1, Sylvain Rabaste2
1Department of Otolaryngology and Otoneurosurgery, Centre Hospitalier Lyon Sud, Hospices Civils de Lyon, Claude Bernard University Lyon 1, Lyon, France.
Objectives:
The aim was to model residual Vestibular Schwannoma (VS) over time to identify prognostic factors of postsurgical growth.
Study Design:
Multicenter retrospective study.
Setting:
Tertiary referral centers.
Patients:
A group of 135 patients who underwent incomplete resection for VS between January 2010 and December 2018. On magnetic resonance imaging (MRI) examinations at baseline (1 year after surgery), patients included were divided into two groups: near-total resection (NTR, <25 mm × 2 mm) and subtotal resection (STR, greater volume).
Intervention:
Monitoring of residual VS volume.
Main Outcome Measures:
3D volumetric segmentation of residual tumors was performed on every MRI examination at baseline and during follow-up to model volume changes over time using the Lambda-Mu-Sigma method.
Results:
The study followed-up 127 patients (median age: 56 yr) over a median follow-up of 39 months. Most VS residues (76.7%; 89/116) showed no growth at 5 years. Only 27 (23.3%) residues showed signs of regrowth (increase in volume >0.05 cm). The extent of resection is a predictor of tumor growth (odds ratio [OR] = 4.85; for STR over NTR; p = 0.003), but the growth rate was significantly different between STR and NTR residues (p < 0.001). At first, over 2 years after surgery, STR residues decreased (-1.0% volume per year), whereas NTR ones grew (+8% per year). Then, both residues showed sign of regrowth.
Conclusion:
Postoperative recommendations should now include the natural history of VS residue after resection: even though the growth rate differs between STR and NTR residues, most VS residues showed no growth.
Insights
Most residual Vestibular Schwannoma (VS) after surgery show no growth, though extent of resection impacts growth rates. Near-total resection (NTR) initially grows faster than subtotal resection (STR) but both eventually regrow.
Area of Science:
- Neurosurgery
- Oncology
- Radiology
Background:
- Vestibular Schwannoma (VS) is a tumor affecting the nerve connecting the ear to the brain.
- Incomplete surgical resection can lead to residual tumor growth, necessitating long-term monitoring.
- Understanding the prognostic factors of postsurgical VS growth is crucial for patient management.
Purpose of the Study:
- To model the volumetric changes of residual Vestibular Schwannoma (VS) over time.
- To identify prognostic factors associated with postsurgical VS growth.
- To compare the growth patterns between near-total resection (NTR) and subtotal resection (STR) of VS.
Main Methods:
- A multicenter retrospective study involving 135 patients with incomplete VS resection.
- 3D volumetric segmentation of residual tumors using MRI scans to model volume changes via the Lambda-Mu-Sigma method.
- Patients were categorized into NTR (<25mm x 2mm) and STR (larger volume) groups based on baseline MRI 1 year post-surgery.
Main Results:
- Out of 127 followed patients, 76.7% showed no VS residue growth at 5 years.
- Tumor regrowth (>0.05cm increase) was observed in 23.3% of residues.
- Extent of resection predicted growth (OR=4.85 for STR vs. NTR; p=0.003), with significantly different growth rates (p<0.001); STR initially decreased (-1.0%/year) while NTR grew (+8%/year), before both eventually regrew.
Conclusions:
- Most residual Vestibular Schwannoma (VS) after incomplete resection do not exhibit significant growth.
- The extent of resection is a key factor influencing residual VS growth dynamics.
- Postoperative management should consider the natural history of residual VS, acknowledging differing growth rates between STR and NTR.
