Petroclival meningiomas (PCMs) represent formidable neurosurgical challenges due to their deep-seated location adjacent to critical structures such as the brainstem, basilar artery, and multiple cranial nerves (1, 2). Arising from the petroclival junction medial to the trigeminal nerve, these tumors often exhibit indolent growth but can attain considerable size, leading to non-specific symptoms such as headache, cranial neuropathies, and gait ataxia (3). While microsurgical techniques have advanced significantly, reducing historical mortality rates (4), postoperative neurological morbidity remains substantial, often exceeding 40% in contemporary series (5, 6).

The central dilemma in PCM surgery is balancing two competing goals: maximal safe resection for long-term oncologic control, and preservation of neurological function to maintain quality of life (7, 8). Although gross total resection is traditionally pursued as the ideal oncological outcome, its pursuit is associated with significant risks, and its functional benefit may not be uniform across all patient subgroups (9). Current decision-making often relies on surgeon experience and general principles, lacking a standardized, evidence-based framework that incorporates critical anatomical and pathological variables.

Specifically, surgical decision-making for PCMs still heavily relies on the surgeon’s experience and subjective judgment, lacking a systematic, individualized, and evidence-based evaluation system. The impact of detailed anatomical tumor-host interfaces, particularly quantitative patterns of cavernous sinus (CS) invasion and neurovascular encirclement, on both resectability and functional outcome is inadequately characterized (10). The prognostic significance of the temporal trajectory of functional recovery, especially early postoperative changes, remains poorly quantified (11). Finally, evidence based WHO grade specific thresholds for the extent of resection are lacking, potentially leading to overtreatment of higher-grade lesions where aggressive resection may offer diminishing returns (12).

To address these gaps, we conducted a comprehensive retrospective analysis of 100 consecutive PCM cases. This study aims to advance beyond prior reports (3, 10) by establishing a preliminary evidence-based framework for individualized resection planning in PCMs. Our approach integrates: Preoperative anatomical risk stratification, Intraoperative decision-modules based on real-time findings, Postoperative functional benchmarking. By reconciling the fundamental tension between maximal resection and functional preservation (4, 9), we provide neurosurgeons with actionable algorithms to optimize both oncologic control and quality of life, addressing a persistent dilemma in skull base surgery (2, 7, 11).

This study is a retrospective analysis and not a clinical trial, as it does not involve prospective experimental interventions. Our study addresses existing gaps in the literature by integrating quantitative interface characterization using high-resolution MRI with functional trajectory mapping through serial Karnofsky Performance Scale (KPS) assessments. This comprehensive approach provides a novel framework for individualized resection planning in PCMs, aiming to enhance the precision and efficacy of surgical decision-making.

The management of petroclival meningiomas (PCMs) remains a formidable challenge in neurosurgery, fundamentally defined by the tension between the pursuit of maximal oncologic control and the imperative of preserving neurological function. While gross total resection is often regarded as the surgical ideal, the quest to achieve it in the eloquent petroclival region carries a significant and well-documented risk of morbidity (13)^. Our study, through a detailed retrospective analysis of 100 consecutive cases, provides empirical evidence that the functional benefit of resection is not a monolithic outcome but is critically modulated by specific anatomical and pathological variables. This finding directly informs a more nuanced, individualized surgical strategy.

Our investigation was designed to address three under-characterized areas in the surgical decision-making process for PCMs. First, regarding anatomical tumor-host interfaces, we moved beyond subjective descriptions by implementing a quantitative, MRI-based grading system for cavernous sinus (CS) invasion and neurovascular encirclement (Figure 2). The strong independent association of high-grade CS invasion with reduced functional gain (OR = 0.52, Table 6) validates the long-held clinical intuition that tumors with extensive involvement of this critical structure pose a disproportionate surgical risk (12, 14). Our data provide a measurable threshold, suggesting that when CS invasion exceeds 180° (Grade 3), the functional advantage of pursuing aggressive resection diminishes, a finding that supports a more conservative surgical goal in such cases to avoid iatrogenic injury (15).

By mapping functional recovery trajectories through serial Karnofsky Performance Scale (KPS) assessments, we were able to define and analyze the 24-month KPS improvement as a robust, patient-centered outcome. This longitudinal approach revealed the heterogeneous nature of recovery. The differential ΔKPS values observed across subgroups (Table 7) are not merely statistical outcomes but reflect the varying biological and anatomical challenges inherent to different tumor types. For instance, the overall modest functional improvement in World Health Organization (WHO) Grade 2 tumors (mean ΔKPS +8) aligns with their more aggressive biology and potentially more complex surgeon-tumor interface, which may limit the extent of safe resection achievable (16).

Our analysis provides preliminary evidence toward establishing WHO grade-specific resection thresholds. The most striking finding is the absence of significant additional functional benefit from complete over subtotal resection for WHO Grade 2 tumors (ΔKPS +8.2 vs. +7.9, p = 0.67, Table 7). This challenges the universal applicability of the gross total resection dogma for atypical meningiomas in this location. It suggests that the incremental oncologic benefit of radical resection may be outweighed by the increased risk of neurological morbidity, supporting an evolving paradigm where maximal safe resection—often intentionally subtotal—followed by adjuvant stereotactic radiosurgery may constitute the optimal management strategy for higher-grade lesions. Our data thus offer an evidence-based rationale for de-escalating surgical aggression in this subgroup, a concept increasingly recognized in skull base surgery.

The individual predictors identified in our multivariable model (Table 6) and the interaction effects revealed in subgroup analyses (Table 7) formed the empirical foundation for our primary contribution: the Resection Utility Score (RUS) and the accompanying three-tier surgical decision algorithm (Figure 1). The RUS is a novel, quantitative metric that crystallizes the risk–benefit calculus into a single, interpretable value. By calculating the ratio of functional gain (ΔKPS) between complete and subtotal resection within defined subgroups (17). The algorithm operationalizes this principle. It advocates for pursuing complete resection in low-risk subgroups (CS Grade 0–1, WHO Grade 1), where the RUS indicates a clear functional advantage (RUS > 1). Conversely, it recommends a shift toward intentional subtotal resection in high-risk subgroups (CS Grade 2–3, WHO Grade 2), where the RUS suggests minimal additional functional benefit (RUS 1 or <1). This framework represents a significant shift from a technically driven philosophy to a patient-outcome-driven strategy (18). The post-hoc simulation suggesting a 35% reduction in attempts at radical resection underscores the algorithm’s potential to reduce surgical morbidity without compromising functional outcomes on a cohort level, a finding that warrants prospective investigation.

Our study reinforces that surgical planning for PCMs must be highly individualized. The decision to operate must balance the natural history of the tumor against surgical risks (19). Once surgery is indicated, our framework provides a structured approach to intraoperative decision-making (20). It aligns with and quantifies the expert consensus that treatment should be tailored based on anatomical complexity and tumor biology (21). Furthermore, it explicitly integrates with multimodal care, as the recommendation for subtotal resection in high-risk cases inherently assumes and validates the role of effective adjuvant therapies like stereotactic radiosurgery for residual disease control (22).

Our study has several limitations that must be acknowledged. The retrospective, single-center design carries inherent risks of selection and information bias, despite our use of propensity score matching and multivariable adjustment. The sample size of 100 patients, particularly within subgroups, limits the statistical power and precision of our estimates, affecting the generalizability of the findings. The RUS and algorithm are derived from and internally validated within the same cohort; thus, their predictive performance requires rigorous external validation in independent, prospective, multicenter studies. Additionally, the WHO grade component of our algorithm currently depends on final histopathology, limiting its utility for purely preoperative planning. Future research should focus on integrating preoperative predictive biomarkers, such as advanced MRI sequences or even molecular signatures from biopsy, to enhance the algorithm’s preoperative applicability. Our study focused on functional outcomes (KPS) at 24 months; long-term studies are needed to correlate this functional outcome-based strategy with key oncological endpoints like progression-free survival (PFS) and overall survival (OS). Finally, the KPS, while widely used, is a physician-reported scale. Future studies would benefit from incorporating patient-reported outcome measures (PROMs) for a more comprehensive assessment of quality of life.

In conclusion, the extent of resection in petroclival meningiomas (PCMs) must be strategically tailored, as its functional benefit is highly dependent on cavernous sinus (CS) invasion patterns and WHO tumor grade. We introduce a data-driven framework featuring a quantitative Resection Utility Score (RUS) and an associated three-tier surgical algorithm. This framework advocates for complete resection in low-risk subgroups (CS invasion Grade 0–1, WHO Grade 1) but recommends a shift toward intentional subtotal resection in high-risk subgroups (CS invasion Grade 2–3, WHO Grade 2), where aggressive surgery offers minimal additional functional benefit. This approach represents a move towards a more personalized, risk-adapted paradigm in skull base surgery, prioritizing the optimization of patient-centered functional outcomes.