Extended Pterional Approach for Medial Sphenoid Wing Meningioma: A Series of 47 Patients

Pterional Craniotomy With Anterior Clinoidectomy for the Resection of a Sphenoid Ridge Meningioma: A Case Report and Two-Dimensional Operative Video

The pterional craniotomy with anterior clinoidectomy is a surgical technique used to resect sphenoid ridge meningiomas. It involves drilling the bone of the anterior clinoid process to gain access to the skull base, including the cavernous sinus and petrous apex particularly. This approach offers several advantages, including excellent exposure of the surgical site, minimal brain retraction, and the ability to visualize and protect critical neurovascular structures. We present a case of a 59-year-old woman presented with headache, dizziness, blurry vision, and unsteady gait for several months. The brain magnetic resonance imaging with gadolinium contrast showed a large space-occupying homogeneously-enhancing lesion at the left skull base, displacing the surrounding structures, including the frontal lobe, temporal lobe, and brainstem. Herein, we present the intraoperative video on a case in which the pterional craniotomy with anterior clinoidectomy that can allow the exposure and resection of the tumor extending into the posterior fossa was utilized for the resection of a large left sphenoid ridge meningioma with brain stem compression.

The Extended Pterional Approach Allows Satisfactory Results for the Resection of Huge Medial Sphenoid Ridge Meningioma

OBJECTIVE

To investigate the surgical method and efficacy of the extended pterional approach in the resection of huge medial sphenoid ridge meningiomas (MSRMs).

METHODS

Retrospective analysis of clinical data from 41 patients diagnosed with MSRMs (diameter ≥4.0 cm) from Nanjing Brain Hospital between January 2012 and February 2022 was conducted. Within 24 hours after surgery, head computed tomography and magnetic resonance imagingwere reviewed to evaluate the extent of tumor resection based on Simpson grading. Cranial magnetic resonance imagingwas repeated 3 to 60 months after surgery to assess tumor recurrence or progression. Preoperative, discharge, and follow-up Karnofsky functional status scores (KPS) were assessed to determine patients' functional status. Repeated-measures analysis of variance was utilized to compare KPS at preoperative, hospital discharge, and final follow-up.

RESULTS

The 41 selected cases included 38 cases (92.7%) of Simpson I-III resection and 3 cases (7.3%) of Simpson IV resection. All the cases had typical pathological features and definite pathological diagnoses. There were 2 recurrent tumors and 4 progressed tumors when the patients were followed up from 3 months to 60 months after operations. The results demonstrated that the KPS score at the final follow-up (91.4 ± 9.6) was higher than at hospital discharge (85.3 ± 8.9) and preoperation (78.2 ± 8.5) (F = 69.46, P = 0.033).

CONCLUSIONS

The use of the extended pterional approach in the resection of huge MSRMs appears to be an effective surgical method. Careful dissection and preservation of vascular and neural structures, as well as meticulous microsurgical techniques in managing cavernous sinus tumors, can lead to reduced surgical complications and improved treatment outcomes.

Impact of Shape Irregularity in Medial Sphenoid Wing Meningiomas on Postoperative Cranial Nerve Functioning, Proliferation, and Progression-Free Survival

Medial sphenoid wing meningiomas (MSWM) are surgically challenging skull base tumors. Irregular tumor shapes are thought to be linked to histopathology. The present study aims to investigate the impact of tumor shape on postoperative functioning, progression-free survival, and neuropathology. This monocentric study included 74 patients who underwent surgery for primary sporadic MSWM (WHO grades 1 and 2) between 2010 and 2021. Furthermore, a systematic review of the literature regarding meningioma shape and the MIB-1 index was performed. Irregular MSWM shapes were identified in 31 patients (41.9%). Multivariable analysis revealed that irregular shape was associated with postoperative cranial nerve deficits (OR: 5.75, 95% CI: 1.15-28.63, p = 0.033). In multivariable Cox regression analysis, irregular MSWM shape was independently associated with tumor progression (HR:8.0, 95% CI: 1.04-62.10, p = 0.046). Multivariable regression analysis showed that irregular shape is independently associated with an increased MIB-1 index (OR: 7.59, 95% CI: 2.04-28.25, p = 0.003). A systematic review of the literature and pooled data analysis, including the present study, showed that irregularly shaped meningiomas had an increase of 1.98 (95% CI: 1.38-2.59, p < 0.001) in the MIB-1 index. Irregular MSWM shape is independently associated with an increased risk of postoperative cranial nerve deficits and a shortened time to tumor progression. Irregular MSWM shapes might be caused by highly proliferative tumors.

Morphological types and localization patterns of pterion in the skulls of adults from southeastern China

PURPOSE

To study the morphological types and relative location of the pterion and its precise relationship with the middle meningeal artery (MMA) in the skulls of adults from southeastern China.

METHODS

Dry skulls (n = 250) of adults were obtained from a university specimen bank and analyzed. The morphological types of the pterions were observed. The distances from the center of the external pterion (Pec) to the relevant intracranial and extracranial marker points were measured using a digital vernier caliper. The anterior, middle, and posterior end points of the external pterion were drilled perpendicular to the bone surface. The precise relationships of the external pterion with the internal pterion and the groove of the frontal branch of the MMA were observed and measured after sawing the skull.

RESULTS

The morphological types of the pterion in the skulls of adults from southeastern China were sphenoparietal suture (SP) (85%), epipteric (12.4%), frontotemporal suture (1.4%), and stellate (1.2%) types. The mean widths of the external and internal pterions were R, 10.68 ± 4.22 mm; L, 11.13 ± 4.40 mm and R, 14.66 ± 4.04 mm; L, 14.14 ± 4.29 mm, respectively, and the width of the internal pterion was slightly longer than that of the external (P < 0.05). No significant difference in pterion width was found between the genders or sides of the skull (both P > 0.05). The distances from the Pec to the posterolateral aspect of the frontozygomatic suture, zygomatic process of the frontal bone, midpoint of the zygomatic arch, and external acoustic meatus were 29.95 ± 3.75 mm, 34.88 ± 4.08 mm, 40.86 ± 3.59 mm, and 53.79 ± 3.82 mm, respectively. These distances were slightly longer on the right side of the skull than on the left side (P < 0.01) and longer in men than in women (P < 0.01). The distances from the Pec to the frontal crest, optic canal, and anterior clinoid process were 62.79 ± 1.15 mm, 45.39 ± 2.48 mm, and 45.47 ± 2.05 mm, respectively. The external and internal pterions were not on the same level, and all the internal pterions were located below the external ones. In the vast majority of the skulls, the groove of the frontal branch of the MMA passed through the posterior end of the external pterion (Pep) or the area between the Pec and Pep.

CONCLUSION

The morphology of the pterion in the skulls of adults from southeastern China is predominantly of the SP type, mostly symmetrically distributed. The distance from the pterion to the extracranially relevant marker points differs among the ethnic groups, between the genders, and between the sides of the skull. All the internal pterions are located below the external ones. Most of the frontal branch of the MMA is located below the mid-posterior segment of the lateral pterion. The characterization of the morphology, the relative position of the pterion and the precise relationship of this structure with the MMA in the skulls of adults from southeastern China may provide an anatomical basis for teaching and clinical practices.

Management of Medial Sphenoid Wing Meningioma Involving the Cavernous Sinus: A Single-Center Series of 105 Cases

OBJECTIVE

Medial sphenoid wing meningiomas are among the three most common intracranial meningiomas. These tumors pose a challenge to neurosurgeons in terms of surgical treatment, as they may involve critical neurovascular structures and invade the cavernous sinus. In case of the latter, a complete resection may not be achievable. The purpose of this study was to investigate prognostic features affecting recurrence and progression-free survival (PFS) of medial sphenoid wing meningiomas involving the cavernous sinus, focusing on the contribution of surgery and postoperative radiotherapy.

METHODS

A retrospective analysis was conducted of the database of our institution, and 105 cases of medial sphenoid wing meningioma with invasion of the cavernous sinus, which were treated between 1998 and 2019, were included. Surgical treatment only was performed in 64 cases, and surgical treatment plus postoperative radiotherapy was performed in 41 cases. Kaplan-Meier analysis was conducted to estimate median survival and PFS rates, and Cox regression analysis was applied to determine significant factors that were associated with each therapeutic modality.

RESULTS

The risk of recurrence was significantly reduced after near-total resection (NTR) (p-value = 0.0011) compared to subtotal resection. Progression-free survival was also significantly prolonged after postoperative radiotherapy (p-value = 0.0002).

CONCLUSIONS

Maximal safe resection and postoperative stereotactic radiotherapy significantly reduced the recurrence rate of medial sphenoid wing meningiomas with infiltration of the cavernous sinus.

Individualized Cerebral Artery Protection Strategies for the Surgical Treatment of Parasellar Meningiomas on the Basis of Preoperative Imaging

Objective

Parasellar meningiomas (PMs) represent a cohort of skull base tumors that are localized in the parasellar region. PMs tend to compress, encase, or even invade the cerebral arteries and their perforating branches. The surgical resection of PMs without damaging neurovascular structures is challenging. This study aimed to analyze functional outcomes in a series of patients who underwent surgery with individualized cerebral artery protection strategies based on preoperative imaging.

Methods

A retrospective review was performed on a single surgeon’s experience of the microsurgical removal of PMs in 163 patients between January 2012 and March 2020. Individualized approaches with a bidirectional dissection strategy were used. Cerebral artery invasion classification, neurological outcomes, MRC Scale for muscle strength, and Karnofsky performance scale were used to assess tumor vascular invasion, functional outcome, and patient quality-of-life outcomes, respectively.

Results

Total resection (Simpson grade I or II) was achieved in 114 patients (69.9%) in our study. A total of 44.7% of patients had improved vision at consecutive follow-ups, 51.1% were stable, and 3.8% deteriorated. Improvements in cranial nerves III, IV, and VI were observed in 41.1%, 36.2%, and 44.8% of patients, respectively. The mean follow-up time was (38.8 ± 27.9) months, and the KPS at the last follow-up was 89.6 ± 8.5. Recurrence was observed in eight patients (13.8%) with cavernous sinus meningiomas, and the recurrence rates in anterior clinoid meningiomas and medial sphenoid wing meningiomas were 3.8% and 2.8%, respectively.

Conclusions

Preoperative imaging is important in the selection of surgical approaches. Maximum tumor resection and cerebral artery protection can be achieved concurrently by utilizing the bidirectional dissection technique. Individualized cerebral artery protection strategies provide great utility in improving a patient’s quality of life.