Surgical Management of Pontine Brainstem Cavernous Malformations: A Systematic Review and Meta-analysis Emphasizing Safe Entry Zones and Clinical Outcomes

Objective: Safe entry zones (SEZs) have emerged as important corridors for accessing brain stem cavernous malformations (BSCM) while minimizing morbidity. This systematic review and meta-analysis aims to analyze the surgical management of pontine BSCM with a focus on SEZs.

Methods: A systematic literature search was performed in PubMed for articles published from 1986 to June 2024 reporting on the surgical management of pontine BSCM. Data were extracted on patient demographics, clinical presentation, BSCM characteristics, surgical approach, use of SEZs, and clinical outcomes. Statistical analyses were performed to identify factors associated with improved outcomes.

Results: Fifty-seven studies with a total of 490 patients were included. The cohort was 54% female with an average age of 33.42 ± 17.7 years. The most common presenting symptoms varied based on BSCM location within the pons. The two most common BSCM locations were peritrigeminal (31.25%) and rhomboid (33.13%). The most frequently used surgical approach was the suboccipital telovelar approach (31.8%), and the most commonly utilized SEZ was the lateral pontine zone (34.1%). Gross total resection was achieved in 65.6% of cases. Good clinical outcome (follow-up mRS < 2) was observed in 64.1% of patients, with an overall mortality rate of 1.0%. The use of SEZs for BSCM located in the middle peduncular region was associated with improved clinical outcomes.

Conclusion: Surgical resection of pontine BSCM can be performed with acceptable morbidity and mortality rates when utilizing SEZs. The lateral pontine, supratrigeminal, and peritrigeminal SEZs are associated with high rates of complete resection and improved neurological outcomes. BSCM location dictates the choice of SEZ and surgical approach, emphasizing the importance of understanding the regional anatomy of the brainstem.

Pontine BSCM patient demographics
Descriptor				Outcome
Cohort				490
Age				33.42 ± 17.7
Hemorrhagic presentation				299
Number of preoperative hemorrhages				1.68 ± 0.92
Duration of preoperative symptoms (wk)				68.63 ± 154.8
Safe entry ones for resection of pontine BSCM
SEZ	Frequency (%)	Location of BSCM	GTR (%)	Change in mRS
LPZ	34.1	PeritrigeminalMiddle peduncle	82.8	-0.86
STZ	12.9	Middle peduncle	72.7	-1.0
PTZ	11.8	middle peduncle	60.0	-0.50
ICZ	9.4	inferior peduncle	75.0	-1.5
Predictive factors associated with improved clinical outcome
Variable		Odds ratio	95% C.I.	p-Value
Preoperative hemorrhage		0.748	0.520–1.076	0.118
Use of SEZ		2.409	1.279–4.54	0.006
GTR		1.369	0.959–1.953	0.083
Basilar pons		0.075	0.010–0.584	0.013
Middle peduncular pons		6.759	2.322–19.673	0.0005
Cross midline		0.466	0.138–1.567	0.217

Publication History

Article published online:
07 February 2025