Surgical resection of petroclival meningiomas of the cerebellopontine angle and/or diaphragma sellae extension via an extended intradural anterior transpetrous approach.

OBJECTIVE: This study aimed to describe the extended intradural anterior transpetrous approach (ATPA) and its usefulness for the surgical resection of petroclival meningiomas (PCMs) of the cerebellopontine angle (CPA) and/or diaphragma sellae (DS) extension. METHODS: Between January 2017 and December 2019, a total of 22 patients with PCMs extending to the CPA/or DS underwent surgery via extended intradural ATPA by the senior author (Xr.X.). We retrospectively analysed the clinical data, radiological findings, surgical treatment, complications, and outcomes of patients and discussed the operative technique. RESULTS: In 22 patients, the tumours were gross totally removed (Simpson I and II) in 18 patients (81.8%), subtotally (Simpson III) in 3 patients (13.6%), and partially (Simpson IV) in 1 patient (4.5%). One patient died 48 days after the operation, and no recurrence was found in 21 patients during a median follow-up of 26 months. Postoperative complications included in abducens nerve palsy in 12 patients with recovery in 10 patients, facial numbness in 4 patients with recovery in 3 patients, and hemiplegia and oculomotor nerve palsy in 1 patient each with recovery in all patients. The postoperative MRI showed temporal lobe oedema but no clinical symptoms in 3 patients. CONCLUSION: Extended intradural ATPA is an alternative approach for PCMs of the CPA and/or DS extension. The single approach can expose both the sellar region and the posterolateral area of the IAC, which is advantageous for extended intradural ATPA.

Petroclival meningiomas: update of current treatment and consensus by the EANS skull base section.

BACKGROUND: The optimal management of petroclival meningiomas (PCMs) continues to be debated along with several controversies that persist. METHODS: A task force was created by the EANS skull base section along with its members and other renowned experts in the field to generate recommendations for the management of these tumors. To achieve this, the task force reviewed in detail the literature in this field and had formal discussions within the group. RESULTS: The constituted task force dealt with the existing definitions and classifications, pre-operative radiological investigations, management of small and asymptomatic PCMs, radiosurgery, optimal surgical strategies, multimodal treatment, decision-making, and patient's counselling. CONCLUSION: This article represents the consensually derived opinion of the task force with respect to the management of PCMs.

Extreme lateral supracerebellar infratentorial approach: how I do it.

BACKGROUND: The extreme lateral supracerebellar infratentorial (ELSI) approach was initially proposed to treat lesions of the posterolateral surface of the pons principally cavernomas. The versatility of the approach allowed its use for other pathologies like gliomas, aneurysms, epidermoids, and meningiomas. METHOD: We describe here the ELSI approach along with its advantages and limits in comparison with other surgical approaches for the treatment of meningiomas of the petroclival region. CONCLUSION: ELSI is a versatile approach that allows access to the anterolateral brainstem surface including extensions to the midbrain diencephalic junction when needed. ELSI compares favorably to other surgical alternatives with respect to the approach-related morbidity, while allowing adequate access to treat the pathology.

Surgical excision of large-to-giant petroclival meningiomas focusing on the middle fossa approaches: The lessons learnt.

INTRODUCTION: Petroclival meningiomas are based on or arising from the petro-clival junction in upper two-thirds of clivus, medial to the fifth cranial nerve. This study focuses on the surgical experience in resecting large-giant tumors >3.5 in size predominantly utilizing middle fossa approaches. MATERIAL AND METHODS: 33 patients with a large or a giant petroclival meningioma (size >3.5 cm) were included. Clinical features, preoperative radiological details, operative findings, and postoperative clinical course at the follow-up visit were reviewed. Group A tumors (n = 17,51.5%) were sized 3.5cm-5cm, and Group B (n = 16,48.48%) tumors were of size >5 cm. Extent of resection was described as 'gross total' (no residual tumor), 'near total' (<10% residual tumor) and 'subtotal resection' (>10% residual tumor). Glasgow outcome scale (GOS) quantitatively scored postoperative neurological outcome (mean follow up: 35.77months; range 1-106 months). RESULTS: 25 (75.8%) patients had tumour extension into both supratentorial and infratentorial compartments. Extension into Meckel's cave (n = 25,75.8%), cavernous sinus (n = 17,48.4%], sphenoid sinus (n = 12,38.7%] and suprasellar area [12,38.7%] was often seen. In 31 (93.9%) patients, the tumor crossed the midline in the premedullary, prepontine, and interpeduncular cisterns. In 20 (60.6%) patients, the tumour extended below and posterior to the internal auditory meatus (IAM), while in 13 (39.4%) patients, the tumor was located above and anterior to the IAM. Kawase's approach was the most commonly used approach in 16 (48.48%) patients and resulted in maximum tumor resection. Other approaches included half-and-half (trans-Sylvian with subtemporal) [n = 6, 18.18%]; frontotemporal craniotomy with orbitozygomatic osteotomy [n = 1, 3%] and retromastoid suboccipital craniectomy (RMSO) [n = 7, 21.21%]. In 2 (6.06%) patients, staged anterior petrosectomy with RMSO; and, in 1, staged presigmoid with half-and-half approach was used. Gross total excision was achieved in 12 (36.36%), near-total excision in 15 (45.45%) and subtotal excision in 6 (18.18%) patients. 20 (60.6%) patients had a good functional outcome; 6 patients succumbed due to meningitis, pneumonitis, perforator injury or a large tumor recurrence. CONCLUSIONS: Half-and-half approach was used in tumors with middle and posterior cranial fossae components often extending to the suprasellar region. Kawase's anterior petrosectomy was utilized in resecting tumors with predominant posterior fossa component (along with a small middle fossa component) that was crossing the midline anterior to the brain stem, and mainly situated superomedial to the IAM. Tumors confined to the posterior fossa, that extended laterally and below the IAM were resected utilizing the RMSO approach. Occasionally, a combination of these approaches was used. Middle fossa approaches help in significantly avoiding morbidity by an early devascularisation and decompression of the tumor. In tumors lacking a plane of cleavage, a thin rim of capsule of tumor may be left to avoid brain stem signs.

Detailed anatomy knowledge: first step to approach petroclival meningiomas through the petrous apex. Anatomy lab experience and surgical series.

Petroclival meningiomas are a challenge for neurosurgeons due to the complex anatomy of the region that is rich of vessels and nerves. A perfect and detailed knowledge of the anatomy is very demanding in neurosurgery, especially in skull base surgery. The authors describe the microsurgical anatomy to perform an anterior petrosectomy based on their anatomical and surgical experience and perform a literature review. The temporal bone is the most complex and fascinating bone of skull base. The apex is located in the angle between the greater wing of the sphenoid and the occipital bone. Removing the petrous apex exposes the clivus. The approach directed through the temporal bone in this anatomical area is referred to as an anterior petrosectomy. The area that must be drilled is the rhomboid fossa that is defined by the Kawase, premeatal, and postmeatal triangles. In Division of Neurosurgery - University of Turin, 130 patients, from August 2013 to September 2015, underwent surgical resection of intracranial meningiomas. In this group, we have operated 7 PCMs and 5 of these were approached performing an anterior petrosectomy with good results. In our conclusions, we feel that this surgery require an advanced knowledge of human anatomy and a specialized training in interpretation of radiological and microsurgical anatomy both in the dissection lab and in the operating room.

The Evolution of Anterior Transpetrosal Approach for the Treatment of Petroclival Meningiomas: A Single-Center 128-Case Experience.

BACKGROUND: The profound understanding of anterior transpetrosal approach (ATPA) is increasingly used to treat petroclival meningiomas (PCMs). We introduce the evolution of ATPA and the outcomes of PCMs treatment. METHODS: Between January 2013 and December 2019, 128 patients with PCMs underwent surgery. According to tumor extension, we classified the 128 patients into 5 types (I-V), introduced key technologies of ATPA into different types for the first time, and achieved a supreme surgical technology. Clinical data, radiological findings, surgical treatments, complications, and patient outcomes were retrospectively analyzed. RESULTS: A total of 22 (17.2%), 44 (34.4%), 25 (19.5%), 29 (22.7%), and 8 (6.3%) patients had type I, II, III, IV, and V disease, respectively. Tumors were gross totally removed (Simpson I and II) in 100 patients (78.1%), subtotally removed (Simpson III) in 20 patients (15.6%), and partially removed (Simpson IV) in 8 patients (6.3%). The progression or recurrence rates were 5% (5/100) for gross totally removed, 22.3% (6/20) for subtotally removed, and 62.5% (5/8; 1 died) for partially removed. According to the Karnofsky Performance Scale and Glasgow Outcome Scale, 108 patients had good recovery (84.4%, 108/128) and 115 were independent (89.8%, 115/128) at the end of follow-up. CONCLUSIONS: Because some key technologies were used in ATPA, the application of ATPA was extended, and greater tumor resection and nerve function protection could be achieved in the treatment of PCMs.

Combined Presigmoid-Subtemporal Approach in a Semi-Sitting Position for Petroclival Meningiomas: A Technical Report.

The removal of petroclival meningiomas (PMs) is considered a neurosurgical challenge due to the critical mobilization of key neurovascular structures. Limited knowledge about the benefits of operating on patients with PMs using the combined presigmoid-subtemporal approach (CPSA) in a semi-sitting position has precluded its generalizability. We report on ten patients with PMs operated in a semi-sitting position using CPSA. We remark that before the surgical approach was accomplished in our group of patients, the CPSA via semi-sitting position was conducted and standardized in six adult cadaveric heads. The neuroanatomic dissections made in cadavers allowed us to confidently use CPSA in our set of patients. There were no comorbidities, perioperative complications, or deaths associated with the surgical procedure. CPSA via a semi-sitting position can be considered a safe approach to remove PMs.

Anterior Transpetrosal Approach for Petroclival Meningioma: Operative Nuances.

Petroclival meningiomas are unique neurosurgical challenges that require planning an approach to the retrosellar and upper and mid retroclival locations. The classical subtemporal-transtentorial approach went into disrepute due to excessive brain retraction. To resolve this challenge Buchenek and Kukwa introduced extradural approach with drilling of the petrous bone and called it the extended middle fossa approach. It was Kawase et al who modified the extended middle fossa approach initially for dealing with basilar trunk aneurysms. This anterior transpetrosal approach has been described below for dealing with the petroclival meningiomas.

Clinical outcomes and survival analysis for petroclival meningioma patients receiving surgical resection: an analysis of 176 cases.

Purpose: The relationship of clinical results and survival analysis of operative patients with petroclival meningioma (PCM) was studied. Patients and methods: Data from a total of 176 PCM patients receiving surgical resection were retrospectively collected. Follow-up was conducted through outpatient review by reexamination telephone calls and letters. Clinical outcomes, survival, and Karnofsky Performance Scale (KPS) data were analyzed. Results: Seventy-two percent of patients (127/176) received only surgery, 8.5% (15/176) received surgery and adjuvant radiation therapy (RT) (surgery + RT), and 19.3% (34/176) received surgery and adjuvant gamma knife surgery (GKS) (surgery + GKS). Gross total resection (GTR) was performed in 34.7% of patients (61/176), subtotal resection (STR) in 58.0% (102/176), and partial resection (PR) in 7.4% (13/176). Recent follow-up KPS was higher than preoperative (80 vs 70, P<0.05) and postoperative KPS (80 vs 70, P<0.05). Cumulative survival was the same for 3, 5, 7, and 9 years, ie, 95%, and mean survival time (MST) was (110.83±2.55) months (95% CI: 105.83-115.83). Recurrence/progression (R/P)-free survival was 88.9%, 86.9%, 71.1% and 71.1%, respectively for 3, 5, 7, and 9 years, and MST was (100.58±3.82) months (95% CI: 93.11-108.06). R/P (HR: 5.486, 95% CI: 1.655-18.180), surgery + RT (HR: 0.125, 95% CI: 0.016-0.990) and WHO grade III (HR: 2.766, 95% CI: 1.146-6.676) were independently associated with cumulative survival. Lack of adhesion to and encasement of neurovascular structures was independently associated with R/P-free survival (HR: 2.002, 95% CI: 1.023-3.919). Conclusion: Surgical treatment was safe and effective for PCM. R/P, surgery + RT, and WHO grade III were independently associated with cumulative survival. Lack of adhesion to and encasement of neurovascular structures was independently associated with R/P-free survival. These factors should be paid attention to in surgical treatment of PCM.

Petroclival meningiomas: Magnetic resonance imaging factors predict tumor resectability and clinical outcome.

OBJECTIVE: Despite advances in skull base surgery, surgical removal of petroclival meningiomas (PCM) still poses a considerable neurosurgical challenge with regard to postoperative morbidity and the patients' long-term outcome. Knowledge of imaging features for PCM that might help to predict common risk factors encountered with tumor resection preoperatively is limited. The aim of this study was to clarify whether MRI features of PCM might predict tumor resectability and clinical outcome. METHODS: A retrospective analysis of 18 cases of PCM treated surgically in our department between 2007 and 2013 was performed. Following radiological tumor features were compared to the extent of tumor resection and the patients' outcome: a) tumor diameter, b) calcification, c) tumor margin towards the brainstem, d) presence of an arachnoidal cleavage plane, e) brainstem edema, f) brainstem compression and g) tumor signal intensity on T2WI. RESULTS: There was an excellent correlation between tumor resectability and preoperative findings with regard to the presence or absence of an arachnoidal cleavage plane and an irregular tumor margin towards the brainstem. Additionally, the presence of brainstem edema was significantly related to surgical morbidity, whereas a high tumor intensity on T2WI correlated significantly with soft tumor consistency and/or vascularity encountered during surgery. CONCLUSION: As demonstrated in our series, PCM with an irregular tumor margin and absence of an arachnoidal plane towards the brainstem should be considered a high-risk group. In these cases, especially when additional brainstem edema is present, limited resection of tumor may be aspired to avoid postoperative morbidity.

Gamma Knife Radiosurgery in Sphenopetroclival Meningiomas: Preliminary Experience at the Iran Gamma Knife Center.

OBJECTIVE: The aims of this study were to characterize the epidemiologic, histologic, and radiologic aspects of sphenopetroclival meningiomas (SpPCMs) and to evaluate the outcome of Gamma Knife radiosurgery (GKRS) either as an adjunct to microsurgery or as a primary SpPCM treatment modality. METHODS: In this retrospective study, medical records of patients with SpPCM who underwent GKRS at the Iran Gamma Knife Center between April 2003 and March 2012 were analyzed. RESULTS: We assessed 122 patients with SpPCMs, including 101 women and 21 men, aged 24-94 years. The mean tumor volume was 12.24 ± 9.30 mL. Patients received 22.32 ± 3.29 Gy and 13.18 ± 1.02 Gy maximal and average marginal dose of GKRS, respectively. The most common complaint was visual impairment, followed by facial sensory impairment and headache. The most frequently involved cranial nerves were III, IV, and VI in 72.1% of patients, followed by II in 52.9%, and V in 35.5%. After radiosurgery, headaches improved in 90.0%, diplopia in 75.0%, and ptosis in 63.0% of patients. On magnetic resonance imaging, tumor size was reduced, unchanged, or increased in 77, 44, and 1 patient, respectively. Progression-free survival at the 5-year follow-up was 56.6%. Younger age (hazard ratio = 0.972, P = 0.011) and lower tumor volume (hazard ratio = 0.959, P = 0.009) were the main prognostic factors for progression-free survival. CONCLUSION: GKRS can be an effective alternative treatment for controlling the progression of SpPCM tumors, producing appropriate clinical outcomes and few complications.

True Petroclival Meningiomas: Proposal of Classification and Role of the Combined Supra-Infratentorial Presigmoid Retrolabyrinthine Approach.

BACKGROUND: The evolution of the surgical treatment of petroclival meningiomas (PMs) has led to a tendency to abandon complex petrous approaches and return to "less-aggressive" skull base approaches. OBJECTIVE: To propose a classification of PMs and establish the role of the combined supra-infratentorial presigmoid retrolabyrinthine (CSIPR) approach in the treatment of PMs rigorously matching the anatomical definition. METHODS: A retrospective analysis was conducted of 51 cases of PMs strictly adhering to the anatomical definition who were operated on from January 1990 to December 2011. On the basis of the different patterns of growth from a common anatomical region of origin, a classification of PMs in 4 groups is proposed. RESULTS: Gross total resection was achieved in 32 patients (63%) and subtotal resection (at least 90% tumor volume removal) in 14 patients (27%). Each of the 4 groups of the proposed classification lends itself to be removed by a distinct surgical approach. Statistical analysis confirmed that such group-approach pairings significantly correlate with radical surgical removal (P < 0.001). Despite the high incidence of early postoperative complications, at late follow-up 82% of patients were free of significant postoperative neurological deficits (95% confidence interval: 70-90). Comparable neurological improvement was observed limited to cases treated by CSIPR (P = 0.60). CONCLUSIONS: For each PM group, the most suitable approach was identified in terms of surgical radicality and low postoperative morbidity. CSIPR can be considered the approach of choice for the most frequent group of PMs in our series. We believe that the CSIPR remains a valuable option for the treatment of PMs.