Multicompartmental cystic trigeminal schwannoma as an uncommon differential diagnosis of cerebellopontine angle tumors

Trigeminal schwannoma is the second most common intracranial schwannoma yet accounts for less than 0.5% intracranial tumors [1]. Cystic degeneration is uncommon. We would like to report a pathologically proven multicompartmental cystic trigeminal schwannoma in a young adult presenting with chronic headache. A literature review on the imaging features of trigeminal schwannoma is performed to assist radiologists in accurate disease localization and prioritizing differential diagnosis in challenging cases. Confident preoperative radiological diagnosis would directly affect management strategies.

Fascicular-Sparing Technique for Resection of Cerebellopontine Angle Facial Nerve Schwannoma

Surgery of cerebellopontine angle (CPA) facial nerve schwannoma (FNS) in patients with good facial nerve function is a challenge.^1-10Video 1 highlights the fascicular-sparing technique for resection of a CPA FNS. A 41-year-old male patient symptomatic with persistent headaches and tinnitus underwent a retrosigmoid approach for a right cystic CPA tumor, presumed vestibular schwannoma. Intraoperatively, the facial nerve was identified as fine multiple strands splayed around the perimetry of the tumor, which elicited a motor response at a low threshold stimulation. This finding led to the intraoperative diagnosis of FNS according to the reported criteria.⁵ Neuromonitoring-assisted fascicular-sparing resection technique was performed. It involved the gradual separation of the uninvolved nerve fibers using a fine-stimulating dissector at a threshold of 0.2 mA. Entry into the tumor was at a stimulation silent cyst. The tumor was debulked with preservation of the endoneurium and pulse irrigation hemostasis. A near-total resection was performed. The patient was discharged on the second postoperative day with a House-Brackman III facial nerve deficit. The deficit remained stable during the following annual follow-up visits. Resection of CPA FNS is indicated at the earliest sign of deficit. However, it might be encountered as masquerading at the surgery of an acoustic tumor. The fascicular-sparing technique is critical in avoiding injuries to the endoneurium during the resection and with the ability to preserve function. The sparing of endoneurium avoids collagenization, fibrosis, and ischemia of the nerve, which are known to be the pathologic substrate of worse functional outcomes.

Cochlear Obliteration after Translabyrinthine Resection for Large Cerebellopontine Angle Tumor

INTRODUCTION

The aim of this study was to better understand the onset time and factors associated with cochlear obliteration following translabyrinthine approach (TLA) surgery for large cerebellopontine angle tumors.

METHODS

This retrospective cohort study included 117 patients with large cerebellopontine angle tumor (tumor diameter >2 cm) treated by TLA surgery from June 2011 to March 2019 in a single tertiary referral center. The Kaplan-Meier method with log-rank test was used to estimate cochlear patency survival and the association between survival and covariates, and the Cox proportional hazards regression analysis was used to identify possible factors associated with cochlear obliteration.

RESULTS

Of the 117 patients included in our analysis, the median follow-up was 24.8 months. There were 30 (25.6%) patients in the cochlear obliteration group, and 87 (74.4%) in the patent cochlear group. Various degrees of cochlear obliteration was found in 25.6% patients in final MRI scan, comprised of 50% grade I, 30% grade II, and 20% grade III. Cochlear patency survival curves showed 94.0% at 3 months, 73.0% at 18 months, which plateaued after 20 months with a survival rate of 71.6%. In the multivariate Cox proportional hazards model, patients presented with postoperative hyperintense T1W cochlear signal had poorer cochlear patency survival compared to isointense T1W (HR = 4.15). Similarly, postoperative deteriorated facial function (HR = 4.52) and full IAC involvement of tumor (HR = 2.33) demonstrated a higher risks of cochlear obliteration after TLA surgery.

CONCLUSION

The 2-year estimated cochlear patency rate was 71.6% in patients that received TLA. Cochlear obliteration can develop as early as 3 months post-surgery, with no new obliteration 20 months after the surgery and half of these patients got severe obliteration. Three factors associated with cochlear obliteration were identified including full IAC involvement of tumor, postoperative facial function deterioration, and postoperative hyperintense T1W cochlear signal.

Percutaneous balloon compression for secondary trigeminal neuralgia caused by cerebellopontine angle tumors

OBJECTIVE

The most common cause for trigeminal neuralgia (TN) is vascular compression at the nerve root, and microvascular decompression (MVD) has been proven to be an effective surgical approach for this disease. For some patients, TN is secondary to the intracranial space-occupying lesion, and tumor resection is usually recommended. However, it is not easy to determine proper treatments when craniotomy is infeasible. In this study, we aim to explore the clinical outcomes of percutaneous balloon compression (PBC) for secondary TN caused by cerebellopontine angle (CPA) tumors.

METHODS

From June 2016 to December 2019, 15 patients with TN caused by CPA tumors underwent PBC in Nanjing Drum Tower Hospital. The clinical features, surgical outcomes, and complications of these patients were analyzed retrospectively.

RESULTS

Fourteen out of the 15 patients had immediate pain relief after successful PBC, while one showed occasional pain, without needing any medication. No patients had a relapse of facial pain within a mean follow-up of 32.5 months. As for surgical complications, 14 patients experienced facial numbness, and six had masseter muscle weakness. No patients experienced serious surgical morbidities.

CONCLUSIONS

For the patients with TN caused by CPA tumors, PBC could be considered a useful technique, especially when craniotomy is infeasible.

Overview of intraoperative neuromonitoring

Intraoperative neuromonitoring (IONM) is used widely to reduce neurologic adverse postoperative outcomes. A variety of techniques are used. Initial techniques were used as far back as the 1930s, and the variety of methods expanded greatly since the 1980s. Many methods monitor baseline findings over time. Other methods test for neurologic function to identify nerves or eloquent cortex. Physicians trained in neurophysiology are key for interpretation of findings, supervision of staff, and making medical recommendations to the surgeon or anesthesiologist. Some neurophysiologists provide the services personally, and in other circumstances well-trained technologist staff help with the techniques. Much IONM is provided by the neurophysiology physician in the operating room, whereas in other cases, the physician may be on-line in real time from a remote site. When monitoring identifies changes, the IONM team must give a clear, timely, and compelling message to the surgeon and anesthesiologist.

Hearing recovery after surgical resection of non-vestibular schwannoma cerebellopontine angle tumors

PURPOSE

Post-operative outcomes for hearing after resection surgery to remove cerebellopontine angle (CPA) tumors other than vestibular schwannomas (VS) are not well understood. This study presents a series of patients with significant post-operative hearing recovery, trying to define the incidence among all patients operated on for removal of non-VS CPA tumors.

METHODS

This is a retrospective observational case series of 8 patients among 69 operated on for removal of non-VS CPA tumors between 2012 and 2020. All patients had pre- and post-operative hearing measurement with pure-tone average (PTA) and speech discrimination score (SDS), according to the American Academy of Otolaryngology-Head and Neck Surgery recommendations, auditory brainstem response (ABR) measurements and imaging.

RESULTS

Six meningiomas and two lower cranial nerve schwannomas operated on with a retrosigmoid approach were included for analysis. The mean pre-operative PTA and SDS were 58 ± 20.7 dB and 13 ± 17.5%, respectively. All patients had pre-operative class D hearing and asynchronous ABRs. They all showed significant hearing recovery, with an improvement of 36 ± 22.2 dB (p = 0.0025) and 85 ± 16.9% (p = 0.0001) in PTA and SDS, respectively, with mean follow-up of 21 ± 23.5 months. Seven patients recovered to a class A hearing level and one patient to class B. The ABRs became synchronous for three patients. The incidence of auditory recovery was 13% for patients operated on with a conservative approach (n = 60).

CONCLUSION

A significant post-operative improvement in hearing could be a reasonable expectation in non-VS tumors extending into the CPA and a retrosigmoid approach should always be considered regardless of pre-operative hearing status.

Not So Benign: A Rare Atypical Ectopic Choroid Plexus Papilloma

Choroid Plexus Papillomas (CPPs) are rare neoplasms (0.4-0.6 % of all brain tumors) arising from cuboidal epithelial cells of the choroid plexus. Atypical choroid plexus papillomas are even more rare and characterized by aggressive features of increased mitotic activity and frequent metastases even at diagnosis. Atypical choroid plexus papillomas accounted for 9% of choroid plexus tumors in the Surveillance Epidemiology and End Results (SEER) Database from 1978 to 2009. We describe a 56 year-old woman with a rare atypical choroid plexus papilloma ectopically located in the cerebellopontine angle and mistaken for a vestibular schwannoma or glossopharyngeal schwannoma. She demonstrated leptomeningeal seeding involving multiple cranial nerves and spinal cord. Besides papilledema she developed several neuro-ophthalmic features slowly over time from involvement of cranial nerves and subsequent intraparenchymal spread and radiation necrosis in the brainstem. Besides being rare, the cerebellopontine angle location of this tumor is also extremely uncommon making this a very unique case.

Postoperative headache after surgical treatment of cerebellopontine angle tumors: a systematic review

Purpose

Postoperative headache (POH) is a complication that occurs after surgical resection of cerebellopontine angle (CPA) tumors. The two most common surgical approaches are the translabyrinthine (TL), and retrosigmoid (RS) approach. The objective of this systematic review was to investigate whether POH occurs more frequently after RS compared to TL approaches.

Methods

A systematic search was conducted in Cochrane, Pubmed and Embase. Studies were included if POH after CPA tumor removal was reported and both surgical approaches were compared. The methodological quality of the studies was assessed using the Risk Of Bias In Non-randomized Studies of Interventions (ROBINS-I) tool.

Results

In total, 3,942 unique articles were screened by title and abstract. After the initial screening process 63 articles were screened for relevance to the inquiry, of which seven studies were included. Three studies found no significant difference between both surgical approaches (p = 0.871, p = 0.120, p = 0.592). Three other studies found a lower rate of POH in the TL group compared to the RS group (p = 0.019, p < 0.001, p < 0.001). Another study showed a significantly lower POH rate in the TL group after one and six months (p = 0.006), but not after 1 year (p = 0.6).

Conclusion

The results of this systematic review show some evidence of a lower rate of POH in favor of the TL approach versus the RS approach for CPA tumor resection. Prospective research studies are needed to further investigate this finding.

The role of socioeconomic status on outcomes following cerebellopontine angle tumor resection

PURPOSE

It is well documented that the interaction between many social factors can affect clinical outcomes. However, the independent effects of economics on outcomes following surgery are not well understood. The goal of this study is to investigate the role socioeconomic status has on postoperative outcomes in a cerebellopontine angle (CPA) tumor resection population.

MATERIALS AND METHODS

Over 6 years (07 June 2013 to 24 April 2019), 277 consecutive CPA tumor cases were reviewed at a single, multihospital academic medical center. Patient characteristics obtained included median household income, Charlson Comorbidity Index (CCI), race, BMI, tobacco use, amongst 23 others. Outcomes studied included readmission, ED evaluation, unplanned return to surgery (during and after index admission), return to surgery after index admission, and mortality within 90 days, in addition to reoperation and mortality throughout the entire follow-up period. Univariate analysis was conducted amongst the entire population with significance set at a p value <0.05. The population was divided into quartiles based on median household income and univariate analysis conducted between the lowest (Q1) and highest (Q4) socioeconomic quartiles, with significance set at a p value <0.05. Stepwise regression was conducted to determine the correlations amongst study variables and identify confounding factors.

RESULTS

Regression analysis of 273 patients did not find household income to be associated with any of the long-term outcomes assessed. Similarly, a Q1 vs Q4 comparison did not yield significantly different odds of outcomes assessed.

CONCLUSION

Although not statistically significant, the odds ratios suggest socioeconomic status may have a clinically significant effect on postsurgical outcomes. Further studies in larger, matched populations are necessary to validate these findings.

Evaluation of balance after surgery for cerebellopontine angle tumor

BACKGROUND

The origin of about 10% of tumors located in the intracranial region is the cerebellopontine angle. Therefore Cerebellopontine Angle (CPA) tumors affect patients' balance.

OBJECTIVE

The aim of this study was to compare the balance in individuals who underwent surgery for CPA tumors with healthy individuals.

METHODS

Thirty patients who were being followed-up by the Department of Neurosurgery and had been operated on CPA tumor and 31 healthy individuals were included in the study as group 1 and group 2, respectively. The participants were evaluated using Romberg Test, Sharpened Romberg Test, One-leg Stance (OLS), Tandem Walking, Walk Across, Berg Balance Scale (BBS), Dizziness Handicap Inventory (DHI) and Short Form 36 (SF-36).

RESULTS

In comparison of the groups, OLS tests (p< 0.001), BBS (p< 0.05) and DHI (p< 0.05) were significantly different in favor of healthy group. SF-36 results revealed a significant difference between the groups, except for Bodily Pain and Vitality (p< 0.05).

CONCLUSIONS

The results of this study demonstrated a decrease in balance parameters and quality of life in individuals who underwent CPA tumor surgery in comparison to healthy individuals. Evaluation of balance in the preoperative and postoperative period should not be ignored in these patients and they are suggested to start rehabilitation in the early postoperative period.

Surgical Outcomes of Cerebellopontine angle Tumors in 50 Cases

INTRODUCTION

To report our experience with a large series of surgical procedures for removal of cerebellopontine angle (CPA) tumors using different approaches.

MATERIALS AND METHODS

This was a retrospective analysis of 50 patients (mean age, 49 years) with CPA tumors (predominantly acoustic neuroma) who underwent surgical removal using appropriate techniques (principally a translabyrinthine approach) during a 4-year period.

RESULTS

One death occurred during this study. There were nine cases (18%) of cerebrospinal fluid leak, and five patients (10%) were diagnosed as having bacterial meningitis. Complete gross tumor removal was not achieved in four patients (8%). Facial nerve function as measured by the House Brackmann system was recorded in all patients 1 year following surgery: 32% had a score of 1 or 2; 26% had a score of 3 or 4; and 8% had a score of 5 or 6. Other complications included four cases of wound infection.

CONCLUSION

The translabyrinthine approach was predominantly used in our series of CPA tumors, and complication rates were comparable with other large case series.