Surgical treatment of acoustic neuroma: Outcomes and indications

Significance of Preoperative Nerve Reconstruction Using Diffusion Tensor Imaging Tractography for Facial Nerve Protection in Vestibular Schwannoma

OBJECTIVE

The facial nerve trace on the ipsilateral side of the vestibular schwannoma was reconstructed by diffusion tensor imaging tractography to identify the adjacent relationship between the facial nerve and the tumor, and to improve the level of intraoperative facial nerve protection.

METHODS

The clinical data of 30 cases of unilateral vestibular schwannoma who underwent tumor resection via retrosigmoid approach were collected between January 2019 and December 2020. All cases underwent magnetic resonance imaging examination before operation. Diffusion tensor imaging and anatomical images were used to reconstruct the facial nerve track of the affected side, so as to predict the course of the nerve and its adjacent relationship with the tumor, to compare the actual trace of the facial nerve during operation, verify the degree of coincidence, and evaluate the nerve function (House-Brackmann grade) after surgery.

RESULTS

The facial nerve of 27 out of 30 cases could be displayed by diffusion tensor imaging tractography, and the tracking rate was 90% (27/30). The intraoperative locations of facial nerve shown in 25 cases were consistent with the preoperative reconstruction results. The coincidence rate was 92.6% (25/27). The facial nerves were located on the anterior middle part of the tumor in 14 cases, anterior upper part in eight cases, anterior lower part in seven cases, and superior polar in one case. Intraoperative facial nerve anatomy was preserved in 30 cases. Among the 30 patients, total resection was performed in 28 cases and subtotal resection in two cases. The facial nerve function was evaluated 2 weeks after operation, and the results showed grade I in 12 cases, grade II in 16 cases and grade III in two cases.

CONCLUSION

Preoperative diffusion tensor imaging tractography can clearly show the trajectory and adjacent position of the facial nerve on the side of vestibular schwannoma, which is beneficial to accurately identify and effectively protect the facial nerve during the operation, and is worthy of clinical application and promotion.

Use of a Novel Clinical Decision-Making Tool in Vestibular Schwannoma Treatment

OBJECTIVE

To determine the usefulness of a personalized tool and its effect on the decision-making process for those with vestibular schwannoma (VS).

STUDY DESIGN

Prospective study.

SETTING

Single institution, academic tertiary care lateral skull base surgery program.

PATIENTS

Patients diagnosed with VS.

INTERVENTIONS

A comprehensive clinical decision support (CDS) tool was constructed from a previously published retrospective patient-reported data obtained from members of the Acoustic Neuroma Association from January to March 2017. Demographic, tumor, and treatment modality data, including associated side effects, were collected for 775 patients and integrated in an interactive and personalized web-based tool.

MAIN OUTCOME MEASURES

Pre- and posttool questionnaires assessing the process of deciding treatment for VS using a decisional conflict scale (DCS) and satisfaction with decision (SWD) scale were compared.

RESULTS

A pilot study of 33 patients evaluated at a single institution tertiary care center with mean ± SD age of 63.9 ± 13.5 years and with average tumor size of 7.11 ± 4.75 mm were surveyed. CDS implementation resulted in a mean ± SD total DCS score decrease from 43.6 ± 15.5 to 37.6 ± 16.4 ( p < 0.01) and total SWD score increase from 82.8 ± 16.1 to 86.2 ± 14.4 ( p = 0.04), indicating a significant decrease in decisional conflict and increase in satisfaction.

CONCLUSIONS

Implementing a decision-making tool after diagnosis of VS reduced decisional conflict and improved satisfaction with decision. Patients considered the tool to be an aid to their medical knowledge, further improving their comfort and understanding of their treatment options. These findings provide a basis for developing predictive tools that will assist patients in making informed medical decisions in the future.

Impact of extent of internal acoustic meatus tumor removal using translabyrinthine approach for acoustic neuroma surgery

Objectives

Many studies have investigated the surgical outcome and predictive factors of acoustic neuroma using different approaches. The present study focused on large tumors due to the greater likelihood of internal acoustic meatus involvement and the greater application of surgical intervention than radiosurgery. There have been no previous reports on outcomes of internal acoustic meatus tumor removal. We investigated the impact of the extent of internal acoustic meatus tumor removal using a translabyrinthine approach for large acoustic neuroma surgery and predictive factors of tumor control.

Methods

This retrospective study reviewed 104 patients with large cerebellopontine angle tumor >3 cm treated by translabyrinthine approach microsurgery. Predictive factors of postoperative facial palsy, tumor control, and extent of internal acoustic meatus tumor removal were assessed.

Results

The mean tumor size was 38.95 ± 6.83 mm. Postoperative facial function showed 76.9% acceptable function (House–Brackmann grade 1 or 2) six months after surgery. The extent of internal acoustic meatus tumor removal was a statistically significant predictor factor of poor postoperative facial function. Younger age, larger tumor size needing radiosurgery, and more extensive removal of tumor were associated with better tumor control.

Conclusion

More extensive internal acoustic meatus tumor removal was associated with poor postoperative facial function and better tumor control.

Microsurgery of Vestibular Schwannoma Post-radiosurgery

Objectives

Microsurgery of vestibular schwannoma (VS) after radiosurgery is not common. In this study, we analyze nerve functional outcomes and technical challenges associated with the microsurgery following radiosurgery of VS.

Materials and Methods

Sixteen patients underwent microsurgery at an average of 37 months (range 3-96 months) after radiosurgery. Indications of surgery included tumour progression or clinical worsening. Twelve of them had never undergone microsurgery before radiosurgery, and three had partial excision before radiosurgery. Maximum tumour diameter of all patients ranged from 23 to 51 mm, of which four were giant tumours. Operative findings and post-microsurgery clinical course, imaging and outcome were analysed.

Results

The tumours found at surgery were firmer, with an avascular core but increased vascularity near the surface. There were thickened arachnoid and often adhesions with surrounding structures making total excision difficult. Near total excision was employed in such cases. Eleven patients underwent gross total/near total resection. No major morbidity or death was reported. Post-surgery, eight patients had grade I/II HB facial function, four had grades III and three had grades IV/V. Of the last three, two had the same deficit preoperatively. At the last follow-up (average 50 months), all patients had a stable facial function. None of the patients have undergone any further radiosurgery/microsurgery since the last intervention.

Conclusion

For the few patients who require microsurgery after radiosurgery, excellent tumour resection with an acceptable outcome can be achieved with proper techniques and neuromonitoring. Leaving tiny residue attached to critical structures is the key to an optimal outcome.

Perioperative Care of the Patient With Acoustic Neuroma

Acoustic neuromas, also known as vestibular schwannomas, are slow-growing, benign tumors that develop on the eighth cranial nerve. Common signs and symptoms of an acoustic neuroma include hearing loss and balance disturbances. A physical examination, a hearing evaluation, and diagnostic imaging assist in the diagnosis of an acoustic neuroma. Patients with a confirmed tumor have three treatment options: observation, stereotactic radiosurgery, and surgical removal. Complications include cerebrospinal fluid leakage, damage to ancillary brain structures, facial nerve damage, and bleeding or vascular injury. This article focuses on the surgical removal of an acoustic neuroma and the role of the perioperative nurse in the perioperative care of the patient.

National Trends in Vestibular Schwannoma Surgery: Influence of Patient Characteristics on Outcomes

Objective To characterize current vestibular schwannoma (VS) surgery outcomes with a nationwide database and identify factors associated with increased complications and prolonged hospital course. Study Design Retrospective review utilizing the University HealthSystem Consortium national inpatient database. Setting US academic health centers. Subjects and Methods Data from patients undergoing VS surgery were analyzed over a 3-year time span (October 2012 to September 2015). Surgical outcomes, such as length of stay (LOS), complications, and mortality, were analyzed on the basis of race, sex, age, and comorbidities during the 30-day postoperative period. Results A total of 3697 VS surgical cases were identified. The overall mortality rate was 0.38%, and the overall complication rate was 5.3%. Advanced age significantly affected intensive care unit LOS, mortality, and complications ( P = .04). Comorbidities, including hypertension, obesity, and depression, also significantly increased complication rates ( P = .02). Sixty-eight patients (1.8%) had a history of irradiation, and they had a significantly increased LOS ( P = .03). Conclusion Modern VS surgery has a low mortality rate and a relatively low rate of complications. Several factors contribute to high complication rates, including age and comorbidities. These data will help providers in counseling patients on which treatment course might be best suited for them.

CT- and MRI-based gross target volume comparison in vestibular schwannomas

AIM

This study represents an enumeration and comparison of gross target volumes (GTV) as delineated independently on contrast-enhanced computed tomography (CT) and T1 and T2 weighted magnetic resonance imaging (MRI) in vestibular schwannomas (VS).

BACKGROUND

Multiple imaging in radiotherapy improves target localization.

METHODS AND MATERIALS

42 patients of VS were considered for this prospective study with one patient showing bilateral tumor. The GTV was delineated separately on CT and MRI. Difference in volumes were estimated individually for all the 43 lesions and similarity was studied between CT and T1 and T2 weighted MRI.

RESULTS

The male to female ratio for VS was found to be 1:1.3. The tumor was right sided in 34.9% and left sided in 65.1%. Tumor volumes (TV) on CT image sets were ranging from 0.251 cc to 27.27 cc. The TV for CT, MRI T1 and T2 weighted were 5.15 ± 5.2 cc, 5.8 ± 6.23 cc, and 5.9 ± 6.13 cc, respectively. Compared to MRI, CT underestimated the volumes. The mean dice coefficient between CT versus T1 and CT versus T2 was estimated to be 68.85 ± 18.3 and 66.68 ± 20.3, respectively. The percentage of volume difference between CT and MRI (%VD: mean ± SD for T1; 28.84 ± 15.0, T2; 35.74 ± 16.3) and volume error (%VE: T1; 18.77 ± 10.1, T2; 23.17 ± 13.93) were found to be significant, taking the CT volumes as the baseline.

CONCLUSIONS

MRI with multiple sequences should be incorporated for tumor volume delineation and they provide a clear boundary between the tumor and normal tissue with critical structures nearby.