Surgical Outcome of Trigeminal Schwannomas

Risk factors of postoperative trigeminal neuropathy in surgical treatment of trigeminal schwannomas

OBJECTIVE

Trigeminal schwannomas are rare benign tumors originating from the Schwann cells of the trigeminal nerve. Despite the common occurrence of trigeminal neuropathy in trigeminal schwannomas, a detailed analysis has not yet been performed because of the rarity of this disease. This study aimed to analyze trigeminal neuropathy in trigeminal schwannoma resection and identify the risk factors for postoperative worsening of trigeminal neuropathy.

METHODS

A retrospective analysis of 86 surgical cases was performed at our institution between 1975 and 2018. Obtained parameters included age, sex, diagnosis, reoperation, tumor size, tumor location, presence or absence of cysts, surgical approach, degree of tumor removal, and pre/postoperative trigeminal neuropathy. Uni- and multivariate analyses were performed to identify the risk factors for worsening postoperative sensory disturbances.

RESULTS

Of 83 patients, 58.1% had preoperative trigeminal neuropathy. Postoperative sensory disturbance occurred in 27.9%, with worsening in two cases and de novo symptoms in 22 cases. Regarding risk factors for worsening postoperative sensory disturbances, older age, smaller tumor size, middle and posterior (MP) type, gross total removal (GTR), and anterior transpetrosal approach were identified in the univariate analysis, while MP type and GTR were identified in the multivariate analysis.

CONCLUSIONS

This study analyzed trigeminal neuropathy in trigeminal schwannomas in detail and identified tumor location and removal rate as risk factors for worsening postoperative sensory disturbances. Treatment strategies to reduce the risk of trigeminal neuropathy should be considered.

Microsurgical Resection of Trigeminal Schwannoma Through Transorbital Approach: 2-Dimensional Operative Video

We present the case of an asymptomatic 34-year-old woman who was found to have an incidental left trigeminal schwannoma.1,2 Owing to the rapid increase in size on imaging, an atypical finding for this type of lesion,3 as well as the risk of cranial nerve involvement and need for tissue diagnosis, the patient underwent a microsurgical left transorbital approach with lateral orbitotomy to resect the lesion.4,5 Piecemeal resection was performed, and the internal contents of the cavernous sinus were preserved. Ultimately, gross total resection was achieved with no residual disease identified on postoperative imaging. No new neurologic deficits were noted after surgery. The technical considerations for the transorbital approach and the literature review on the outcomes for middle fossa lesions accessed by a lateral orbitotomy are reviewed.6-10 The patient consented to the procedure and to the publication of her images. Institutional Review Board approval was deemed unnecessary due to the retrospective, case-report nature of this work.

Clinical characteristics and outcomes after trigeminal schwannoma resection: a multi-institutional experience

Given their rarity, the clinical course of patients undergoing trigeminal schwannoma (TS) resection remains understudied. The objective of this study is to describe clinical characteristics and outcomes in patients undergoing surgical resection for TS in a multi-institutional cohort. This is a retrospective study of patients undergoing TS resection at two institutions between 2004 and 2022. Patient, radiographic, and clinical characteristics were reviewed and analyzed with standard statistical methods. Thirty patients were included. The median patient age was 43 (IQR: 35-52) years, and 14 (47%) patients were female. Median clinical and radiographic follow-ups were 43 (IQR: 20-81) and 47 (IQR: 27-97) months respectively. The most common presenting symptoms were trigeminal hypesthesia (57%) and headaches (30%), diplopia (30%), and ataxia/cerebellar signs (30%). The median maximum tumor diameter was 3.3 (IQR: 2.5-5.4) cm. Most tumors were Samii type C (50%) and mixed cystic-solid (63%). Surgical approaches included endoscopic endonasal (33%), supratentorial (30%), combined/staged (20%), infratentorial (10%), and anterior petrosal (7%) approaches. Gross-total resection was achieved in 16 (53%) patients. Radiographic tumor recurrence was noted in four patients at a median of 79 (range 5-152) months. Twenty-six (87%) patients reported improvements in at least one symptom by last follow-up. The most common perioperative complication was new cranial nerve deficit, with 17% of patients having a transient deficit and 10% having a permanent cranial nerve deficit. Surgical resection of TS showed good progression-free survival and symptom improvement, but was associated with cranial nerve deficits.

Treating Trigeminal Schwannoma through a Transorbital Approach: A Systematic Review

Background: Trigeminal schwannomas (TSs) are uncommon tumors found along any segment of the fifth cranial nerve (CN V). Typically located at the skull base, these benign tumors carry substantial morbidity due to the extent of traditional surgical methods. Minimally invasive endoscopic surgery such as the endoscopic transorbital approach (ETOA) presents promising new avenues for treatment, with the transorbital approach emerging as a potentially successful alternative. Methods: This review systematically assesses the application of the ETOA in treating TSs. PubMed, Ovid MEDLINE, and Embase were thoroughly searched for articles detailing the use of the ETOA in clinical case studies. The outcomes of interest encompassed epidemiological profiling, surgical results, and complication rates. Results: This study included 70 patients with TSs (from six studies), with 22 males (31.4%) and 58 females (68.6%). Patients averaged 55 years and were monitored for around 16.4 months (on average). In most tumors, the middle cranial fossa was involved to some degree. The majority (87.2%) were large (3-6 cm) and underwent gross total resection (GTR) or near-total resection in 87.2% of patients. Preoperatively, sensory alterations were common, along with proptosis, neuropathic pain, and diplopia. Postoperatively, complications included ptosis, diplopia, sensory impairment, corneal keratopathy, masticatory difficulty, and neuralgia. The pure ETOA was the primary surgical technique used in 90% of cases, with no recurrence observed during the follow-up period. Conclusions: Using the ETOA to treat TSs demonstrated an oncologic control rate of 87.2%. Postoperative complications including ptosis, diplopia, and sensory disturbances have been observed, but careful monitoring and management can mitigate these problems. The ETOA emerges as a viable surgical option, especially for tumors involving the middle cranial fossa, capable of adapting to individual patient needs and demonstrating efficacy in TS management.

Preservation of cranial nerve function in large and giant trigeminal schwannoma resection: a case series

BACKGROUND

Trigeminal schwannomas (TSs) are intracranial tumors that can cause significant brainstem compression. TS resection can be challenging because of the risk of new neurologic and cranial nerve deficits, especially with large (≥ 3 cm) or giant (≥ 4 cm) TSs. As prior surgical series include TSs of all sizes, we herein present our clinical experience treating large and giant TSs via microsurgical resection.

METHODS

This was a retrospective, single-surgeon case series of adult patients with large or giant TSs treated with microsurgery in 2012-2023.

RESULTS

Seven patients underwent microsurgical resection for TSs (1 large, 6 giant; 4 males; mean age 39 ± 14 years). Tumors were classified as type M (middle fossa in the interdural space; 1 case, 14%), type ME (middle fossa with extracranial extension; 3 cases, 43%), type MP (middle and posterior fossae; 2 cases, 29%), or type MPE (middle/posterior fossae and extracranial space; 1 case, 14%). Six patients were treated with a frontotemporal approach (combined with transmastoid craniotomy in the same sitting in one patient and a delayed transmaxillary approach in another), and one patient was treated using an orbitofrontotemporal approach. Gross total resection was achieved in 5 cases (2 near-total resections). Five patients had preoperative facial numbness, and 6 had immediate postoperative facial numbness, including two with worsened or new symptoms. Two patients (28%) demonstrated new non-trigeminal cranial nerve deficits over mean follow-up of 22 months. Overall, 80% of patients with preoperative facial numbness and 83% with facial numbness at any point experienced improvement or resolution during their postoperative course. All patients with preoperative or new postoperative non-trigeminal tumor-related cranial nerve deficits (4/4) experienced improvement or resolution on follow-up. One patient experienced tumor recurrence that has been managed conservatively.

CONCLUSIONS

Microsurgical resection of large or giant TSs can be performed with low morbidity and excellent long-term cranial nerve function.

Operative management of trigeminal schwannomas: based on a modified classification in a study of 93 cases

BACKGROUND

Advances in microscopic and endoscopic surgical techniques have outpaced traditional classification and transcranial surgical strategies, especially with reference to the treatment of trigeminal schwannomas (TSs). A modified TS classification is proposed and appropriate surgical strategies are discussed.

METHODS

The cases of 93 patients who underwent surgical treatment in Beijing Tiantan Hospital in the previous 6 years were analyzed retrospectively, and a literature review was conducted.

RESULTS

Classification is based on surgical direction. Tumors were classified as follows: type A, backward orientation, located in the orbit or orbit and middle cranial fossa (8 cases, 8.6%); type B, upward orientation, located in the pterygopalatine fossa, infratemporal fossa or pterygopalatine fossa, infratemporal fossa, and middle cranial fossa (23 cases, 24.7%); type C, forward and backward orientations, located in the middle cranial fossa, posterior cranial fossa or both (58 cases, 62.4%); and type D, located in multiple regions (4 cases, 4.3%). 91.40% of patients underwent gross total resection (GTR) with 29 cases receiving endoscopic resection of whom 93.10% (27/29) experienced GTR.

CONCLUSION

The 93 cases were satisfactorily divided into four types, according to tumor location and surgical orientation, enabling safe and effective removal by appropriate surgery.

Endoscopic far-lateral supracerebellar infratentorial approach for resection of dumbbell-shaped trigeminal schwannoma: surgical techniques and preliminary results

BACKGROUND

Trigeminal schwannomas (TSs) are mostly benign tumors. However, dumbbell-shaped TSs are most challenging for surgeons and pose a high surgical risk.

OBJECTIVE

We describe the technique of the purely endoscopic far-lateral supracerebellar infratentorial approach (EFL-SCITA) for removing dumbbell-shaped TSs and further discuss the feasibility of this approach and our experience.

METHODS

EFL-SCITA was performed for resection of 5 TSs between January 2020 and March 2023. The entire procedure was performed endoscopically with the goal of total tumor resection. During the operation, the tumor was exposed in close proximity and multiple angles under the endoscope, and the peri-tumor nerves were carefully identified and protected, especially the normal trigeminal fiber bundles around the tumor.

RESULTS

All the tumors of 5 patients involved the middle and posterior cranial fossa, of which total removal was achieved in 2 patients and near-total removal in 3 patients. The most common preoperative symptoms were relieved after surgery. Two patients had postoperative mild facial paralysis (House-Brackmann grade II), and 1 patient had abducens palsy; both recovered during the follow-up period. Two patients experienced new postoperative facial hypesthesia, and 1 experienced mastication weakness, which did not recover. There was no tumor recurrence or residual tumor growth during the follow-up period in any of the patients.

CONCLUSION

EFL-SCITA is a new and effective alternative for the surgical treatment of TSs. For dumbbell-shaped TSs, this approach provides sufficient surgical field exposure and freedom of operation.

Endoscopic Lateral and Superior Cerebellar Keyhole Approach to the Anterior and Middle Incisural Space and Meckel Cave: An Anatomic Study

OBJECTIVE

We sought to assess the feasibility of endoscopic lateral and superior cerebellar keyhole approach for exposure of the anterior and middle incisural space and Meckel cave.

METHODS

The endoscopic lateral and superior cerebellar keyhole approach was performed in 6 cadaveric heads (12 sides) using 0- and 30-degree endoscopes, respectively. The anatomic structures for this approach to the anterior and middle incisural space and Meckel cave were observed.

RESULTS

By grinding out the suprameatal tubercle and petrous apex and incising the tentorium, the anatomic structures in the anterior incisural space were visualized. The mean area exposed with a 0-degree endoscope in the anterior incisural space was 212.50 ± 6.04 mm2, significantly less than that exposed with a 30-degree endoscope (233.83 ± 8.72 mm2) (P < 0.05). The anatomic distance of the Meckel cave in the depth was the same between a 0-degree endoscope and a 30-degree endoscope; however, the distance in the width was 9.48 and 12.32 mm, respectively (P < 0.01). The area of petrous window grinded by a 30-degree endoscope was only increased by 5.83 mm2, compared with a 0-degree endoscope (P > 0.05).

CONCLUSIONS

This approach provides access to the anterior and middle incisural space and Meckel cave, which is feasible to clearly expose the anatomic structures in those regions with minimal invasiveness. Additionally, better visualization and surgical space can be achieved under a 30-degree endoscope.

Outcomes following surgical resection of trigeminal schwannomas: a systematic review and meta-analysis

Although typically benign, trigeminal schwannomas (TS) may require surgical resection when large or symptomatic and can cause significant morbidity. This study aims to summarize the literature and synthesize outcomes following surgical resection of TS. A systematic review was performed according to PRISMA guidelines. Data extracted included patient and tumor characteristics, surgical approaches, and postoperative outcomes. Odds ratios (OR) with corresponding 95% confidence intervals (CI) were used for outcome analysis. The initial search yielded 1838 results, of which 26 studies with 974 patients undergoing surgical resection of TS were included. The mean age was 42.9 years and 58.0% were female. The mean tumor diameter was 4.7 cm, with Samii type A, B, C, and D tumors corresponding to 33.4%, 15.8%, 37.2%, and 13.6%, respectively. Over a mean symptom duration of 29 months, patients presented with trigeminal hypesthesia (58.7%), headache (32.8%), trigeminal motor weakness (22.8%), facial pain (21.3%), ataxia (19.4%), diplopia (18.7%), and visual impairment (12.0%). Surgical approaches included supratentorial (61.4%), infratentorial (15.0%), endoscopic (8.6%), combined/staged (5.3%), and anterior (5.7%) or posterior (4.0%) petrosectomy. Postoperative improvement of facial pain (83.9%) was significantly greater than trigeminal motor weakness (33.0%) or hypesthesia (29.4%). The extent of resection (EOR) was reported as gross total (GTR), near total, and subtotal in 77.7%, 7.7%, and 14.6% of cases, respectively. Over a mean follow-up time of 62.6 months, recurrence/progression was noted in 7.4% of patients at a mean time to recurrence of 44.9 months. Patients with GTR had statistically significantly lower odds of recurrence/progression (OR: 0.07; 95% CI: 0.04-0.15) compared to patients with non-GTR. This systematic review and meta-analysis report patient outcomes following surgical resection of TS. EOR was found to be an important predictor of the risk of recurrence. Facial pain was more likely to improve postoperatively than facial hypesthesia. This work reports baseline rates of post-operative complications across studies, establishing benchmarks for neurosurgeons innovating and working to improve surgical outcomes for TS patients.

Surgical Management of Jugular Foramen Schwannomas

Simple Summary

Treatments of jugular foramen schwannomas may be challenging due to critical anatomical relations and the involvement of different aspects of the skull base. Advances in microsurgery have led to improved outcomes over recent decades, whereas in contrast, some advocate stereotactic radiotherapy as an effective therapy, controlling the tumor volume with few complications. In this manuscript, we present the outcomes and adverse events in a contemporary cohort and discuss surgical advantages and disadvantages of different performed classic skull base approaches.

Abstract

Background: Resection of jugular foramen schwannomas (JFSs) with minimal cranial nerve (CN) injury remains difficult. Reoperations in this vital region are associated with severe CN deficits. Methods: We performed a retrospective analysis at a tertiary neurosurgical center of patients who underwent surgery for JFSs between June 2007 and May 2020. We included nine patients (median age 60 years, 77.8% female, 22.2% male). Preoperative symptoms included hearing loss (66.6%), headache (44.4%), hoarseness (33.3%), dysphagia (44.4%), hypoglossal nerve palsy (22.2%), facial nerve palsy (33.3%), extinguished gag reflex (22.2%), and cerebellar dysfunction (44.4%). We observed Type A, B, C, and D tumors in 3, 1, 1, and 4 patients, respectively. A total of 77.8% (7/9) underwent a retrosigmoid approach, and 33.3% (3/9) underwent an extreme lateral infrajugular transcondylar (ELITE) approach. Gross total resection (GTR) was achieved in all cases. The rate of shunt-dependent hydrocephalus was 22.2% (2/9). No further complications requiring surgical intervention occurred during follow-up. The median follow-up time was 16.5 months (range 3–84 months). Conclusions: Considering the satisfying outcome, the GTR of JFSs is feasible in performing well-known skull base approaches. Additional invasive and complicated approaches were not needed. Radiosurgery may be an effective alternative for selected patients.