Publications by authors named "Colin L W Driscoll"

126 Publications

Cochlear implantation after radiosurgery for vestibular schwannoma.

J Neurosurg 2021 07 24;135(1):126-135. Epub 2021 Jun 24.

1Department of Otolaryngology-Head and Neck Surgery, and.

Objective: The object of this study was to ascertain outcomes of cochlear implantation (CI) following stereotactic radiosurgery (SRS) for vestibular schwannoma (VS).

Methods: The authors conducted a retrospective chart review of adult patients with VS treated with SRS who underwent CI between 1990 and 2019 at a single tertiary care referral center. Patient demographics, tumor features, treatment parameters, and pre- and postimplantation audiometric and clinical outcomes are presented.

Results: Seventeen patients (18 ears) underwent SRS and ipsilateral CI during the study period. Thirteen patients (76%) had neurofibromatosis type 2 (NF2). Median age at SRS and CI were 44 and 48 years, respectively. Median time from SRS to CI was 60 days, but notably, 4 patients underwent SRS and CI within 1 day and 5 patients underwent CI more than 7 years after SRS. Median marginal dose was 13 Gy. Median treatment volume at the time of SRS was 1400 mm3 (range 84-6080 mm3, n = 15 patients). Median post-CI PTA was 28 dB HL, improved from 101 dB HL preoperatively (p < 0.001). Overall, 11 patients (12 ears) exhibited open-set speech understanding. Sentence testing was performed at a median of 10 months (range 1-143 months) post-CI. The median AzBio sentence score for patients with open-set speech understanding was 76% (range 19%-95%, n = 10 ears). Two ears exhibited Hearing in Noise Test (HINT) sentence scores of 49% and 95%, respectively. Four patients achieved environmental sound awareness without open-set speech recognition. Two had no detectable auditory percepts.

Conclusions: Most patients who underwent CI following SRS for VS enjoyed access to sound at near-normal levels, with the majority achieving good open-set speech understanding. Implantation can be performed immediately following SRS or in a delayed fashion, depending on hearing status as well as other factors. This strategy may be applied to cases of sporadic or NF2-associated VS.

Abbreviations: AAO-HNS = American Academy of Otolaryngology-Head and Neck Surgery; ABI = auditory brainstem implant; CI = cochlear implantation; CN = cranial nerve; CNC = consonant-nucleus-consonant; CPA = cerebellopontine angle; EPS = electrical promontory stimulation; ESA = environmental sound awareness; HINT = Hearing in Noise Test; IAC = internal auditory canal; NF2 = neurofibromatosis type 2; OSP = open-set speech perception; PTA = pure tone average; SRS = stereotactic radiosurgery; VS = vestibular schwannoma; WRS = word recognition score.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3171/2020.4.JNS201069DOI Listing
July 2021

Differential Impact of Advanced Age on Clinical Outcomes After Vestibular Schwannoma Resection in the Very Elderly: Cohort Study.

Oper Neurosurg (Hagerstown) 2021 Aug;21(3):104-110

Department of Neurosurgery, Mayo Clinic, Rochester, Minnesota.

Background: Vestibular schwannomas (VS) have a peak incidence in the sixth and seventh decades of life. Stereotactic radiosurgery is often the preferred treatment for VS among patients of advanced age. The fraction of elderly patients potentially requiring consideration for surgical treatment is anticipated to expand, mandating an update to management paradigms in this population.

Objective: To describe our experience with surgical management of VS in patients aged 75 yr and older.

Methods: Cohort study of all patients aged ≥75 yr with sporadic VS requiring surgical treatment at our institution between 1999 and 2020. Data included preoperative baseline characteristics and outcome data including extent of resection, facial nerve and hearing status, functional outcome, length of stay, and complications.

Results: A total of 24 patients were included, spanning an age range of 75 to 90 yr. Average tumor size was 2.76 ± 1.04 cm, and average baseline Modified 5-item Frailty Index (mFI-5) score was 1.08 ± 0.93. Extent of resection was gross total in 5 (20.8%), near total in 3 (12.5%), and sub-total resection in the remaining 16 (66.7%). One patient died in the postoperative period because of an acute sub-dural hematoma. Favorable facial nerve function (HB1-2) was preserved in 12 patients (75%) between 75 and 79 yr and 2 patients (28.6%) aged ≥ 80 yr. No cerebrospinal fluid leak or surgical site infection was observed; 3 patients developed hydrocephalus requiring ventriculo-peritoneal shunt placement. Nine patients required out-of-home disposition; all patients eventually returned to independent living.

Conclusion: Microsurgical resection of VS can be safely undertaken in patients greater than 75 y/o but may carry an increased risk of poor facial function.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1093/ons/opab170DOI Listing
August 2021

Anatomical Step-by-Step Dissection of Complex Skull Base Approaches for Trainees: Surgical Anatomy of the Retrosigmoid Approach.

J Neurol Surg B Skull Base 2021 Jun 28;82(3):321-332. Epub 2019 Oct 28.

Department of Neurologic Surgery, Mayo Clinic, Rochester, Minnesota, United States.

 Neurosurgical anatomy is traditionally taught via anatomic and operative atlases; however, these resources present the skull base using views that emphasize three-dimensional (3D) relationships rather than operative perspectives, and are frequently written above a typical resident's understanding. Our objective is to describe, step-by-step, a retrosigmoid approach dissection, in a way that is educationally valuable for trainees at numerous levels.  Six sides of three formalin-fixed latex-injected specimens were dissected under microscopic magnification. A retrosigmoid was performed by each of three neurosurgery residents, under supervision by the senior authors (C.L.W.D. and M.J.L.) and a graduated skull base fellow, neurosurgeon, and neuroanatomist (M.P.C.). Dissections were supplemented with representative case applications.  The retrosigmoid craniotomy (aka lateral suboccipital approach) affords excellent access to cranial nerve (CN) IV to XII, with corresponding applicability to numerous posterior fossa operations. Key steps include positioning and skin incision, scalp and muscle flaps, burr hole and parasigmoid trough, craniotomy flap elevation, initial durotomy and deep cistern access, completion durotomy, and final exposure.  The retrosigmoid craniotomy is a workhorse skull base exposure, particularly for lesions located predominantly in the cerebellopontine angle. Operatively oriented neuroanatomy dissections provide trainees with a critical foundation for learning this fundamental skull base technique. We outline a comprehensive approach for neurosurgery residents to develop their familiarity with the retrosigmoid craniotomy in the cadaver laboratory in a way that simultaneously informs rapid learning in the operating room, and an understanding of its potential for wide clinical application to skull base diseases.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1055/s-0039-1700513DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8133810PMC
June 2021

Long-term outcomes of grade I/II skull base chondrosarcoma: an insight into the role of surgery and upfront radiotherapy.

J Neurooncol 2021 Jun 27;153(2):273-281. Epub 2021 Apr 27.

Departments of Neurologic Surgery, Mayo Clinic, Rochester, MN, USA.

Purpose: To clarify the need for post-operative radiation treatment in skull base chondrosarcomas (SBCs).

Methods: A retrospective analysis of patients with grade I or II SBC. Patients were divided according to post-surgical treatment strategies: (A) planned upfront radiotherapy and (B) watchful waiting. Tumor control and survival were compared between the treatment groups. The median follow-up after resection was 105 months (range, 9-376).

Results: Thirty-two patients (Grade 1, n = 16; Grade 2, n = 16) were included. The most frequent location was petroclival (21, 64%). A gross total resection (GTR) was achieved in 11 patients (34%). Fourteen (44%) underwent upfront radiotherapy (group A) whereas 18 (56%) were followed with serial MRI alone (group B). The tumor control rate for the entire group was 77% and 69% at 10- and 15-year, respectively. Upfront radiotherapy (P = 0.25), extent of resection (P = 0.11) or tumor grade (P = 0.83) did not affect tumor control. The majority of Group B patients with recurrent tumors (5/7) obtained tumor control with repeat resection (n = 2), salvage radiotherapy (n = 2), or a combination of both (n = 1). The 10-year disease-specific survival was 95% with no difference between the group A and B (P = 0.50).

Conclusion: For patients with grade I/II SBC, a reasonable strategy is deferral of radiotherapy after maximum safe resection until tumor progression or recurrence. At that time, most patients can be successfully managed with salvage radiotherapy or surgery. Late recurrences may occur, and life-long follow-up is advisable.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s11060-021-03764-0DOI Listing
June 2021

Language and Audiological Outcomes Among Infants Implanted Before 9 and 12 Months of Age Versus Older Children: A Continuum of Benefit Associated With Cochlear Implantation at Successively Younger Ages.

Otol Neurotol 2021 06;42(5):686-693

Department of Otolaryngology-Head and Neck Surgery.

Objective: To compare language and audiological outcomes among infants (<9 and <12 mo) and older children receiving cochlear implantation (CI).

Study Design: Retrospective chart review.

Setting: Tertiary academic referral center.

Patients: Pediatric patients receiving CI between October 1995 and October 2019.

Intervention: Cochlear implantation.

Main Outcome Measures: Most recent language and audiological assessment scores were evaluated by age group.

Results: A total of 118 children were studied, including 19 who were implanted <9 months of age, 19 implanted 9 to <12 months of age, and 80 implanted 12 to <36 months of age. The mean duration of follow-up was 7.4 ± 5.0 years. Most recent REEL-3 receptive (88 ± 12 vs. 73 ± 15; p = 0.020) and expressive (95 ± 13 vs. 79 ± 12; p = 0.013) communication scores were significantly higher in the <9 months group compared to the 9 to <12 months group. PLS and OWLS auditory comprehension and oral expression scores were significantly higher in the <12 months group compared to the 12 to <36 months group. The difference in NU-CHIPS scores between <12 and 12 to <36 months was statistically significant (89% ± 6 vs. 83% ± 12; p = 0.009). LNT scores differed significantly between <9 and 9 to <12 months (94% ± 4 vs. 86% ± 10; p = 0.028).

Conclusions: The recent FDA expansion of pediatric CI eligibility criteria to include infants as young as 9 months of age should not serve as a strict clinical cutoff. Rather, CI can be pursued in appropriately selected younger infants to optimize language and audiological outcomes.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1097/MAO.0000000000003011DOI Listing
June 2021

Prevalence of Surgical, Anesthetic, and Device-related Complications Among Infants Implanted Before 9 and 12 Months of Age Versus Older Children: Evidence for the Continued Expansion of Pediatric Cochlear Implant Candidacy Criteria.

Otol Neurotol 2021 07;42(6):e666-e674

Department of Otolaryngology-Head and Neck Surgery.

Objective: To compare the prevalence of surgical, anesthetic, and device-related complications among infants and older children receiving cochlear implantation (CI).

Study Design: Retrospective chart review.

Setting: Tertiary academic referral center.

Patients: Pediatric patients who underwent CI from November 1990 to January 2020.

Intervention: CI.

Main Outcome Measures: Surgical, anesthetic, and device-related complication rates were compared by age group (<12 versus 12-23 versus 24+ months with subset analysis of <9 versus 9-11 months).

Results: A total of 406 primary pediatric CI surgeries encompassing 482 ears were analyzed, including 45 ears in 23 patients implanted less than 9 months and 89 ears in 49 patients less than 12 months. No anesthetic complications occurred. Postoperative surgical and device-related complication rates were not significantly different among the less than 12, 12 to 23, and 24+ month groups (16% versus 16% versus 12%; p = 0.23) or between the less than 9 and 9 to 11 month groups (22% versus 9%; p = 0.09). Thirty-day readmission was significantly higher for patients less than 12 months compared with patients 24+ months (6% versus <1%; p = 0.011), but was not significantly higher compared with patients 12 to 23 months (6% versus 3%; p = 0.65). Reoperation rates did not differ significantly among the less than 12, 12 to 23, and 24+ month groups (10% versus 7% versus 6%; p = 0.31).

Conclusions: The prevalence of surgical, anesthetic, and device related complications was not significantly different among infants implanted less than 9 or less than 12 months of age when compared with older children. These data provide evidence for the continued expansion of pediatric cochlear implant candidacy criteria to include appropriately selected infants less than 9 months of age.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1097/MAO.0000000000003060DOI Listing
July 2021

Working Toward Consensus on Sporadic Vestibular Schwannoma Care: A Modified Delphi Study.

Otol Neurotol 2020 Dec;41(10):e1360-e1371

Hong Kong Neurosurgical Associates, Hong Kong SAR, People's Republic of China.

Objective: To address variance in clinical care surrounding sporadic vestibular schwannoma, a modified Delphi study was performed to establish a general framework to approach vestibular schwannoma care. A multidisciplinary panel of experts was established with deliberate representation from key stakeholder societies. External validity of the final statements was assessed through an online survey of registered attendees of the 8th Quadrennial International Conference on Vestibular Schwannoma.

Study Design: Modified Delphi method.

Methods: The panel consisted of 16 vestibular schwannoma experts (8 neurotology and 8 neurosurgery) and included delegates representing the AAOHNSF, AANS/CNS tumor section, ISRS, and NASBS. The modified Delphi method encompassed a four-step process, comprised of one prevoting round to establish a list of focus areas and three subsequent voting rounds to successively refine individual statements and establish levels of consensus. Thresholds for achieving moderate consensus, at ≥67% agreement, and strong consensus, at ≥80% agreement, were determined a priori. All voting was performed anonymously via the Qualtrics online survey tool and full participation from all panel members was required before procession to the next voting round.

Results: Through the Delphi process, 103 items were developed encompassing hearing preservation (N = 49), tumor control and imaging surveillance (N = 20), preferred treatment (N = 24), operative considerations (N = 4), and complications (N = 6). As a result of item refinement, moderate (4%) or strong (96%) consensus was achieved in all 103 final statements. Seventy-nine conference registrants participated in the online survey to assess external validity. Among these survey respondents, moderate (N = 21, 20%) or strong (N = 73, 71%) consensus was achieved in 94 of 103 (91%) statements, and no consensus was reached in 9 (9%). Of the four items with moderate consensus by the expert panel, one had moderate consensus by the conference participants and three had no consensus.

Conclusion: This modified Delphi study on sporadic vestibular schwannoma codifies 100% consensus within a multidisciplinary expert panel and is further supported by 91% consensus among an external group of clinicians who regularly provide care for patients with vestibular schwannoma. These final 103 statements address clinically pragmatic items that have direct application to everyday patient care. This document is not intended to define standard of care or drive insurance reimbursement, but rather to provide a general framework to approach vestibular schwannoma care for providers and patients.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1097/MAO.0000000000002917DOI Listing
December 2020

Vestibular Schwannoma Practice Patterns: An International Cross-specialty Survey.

Otol Neurotol 2020 12;41(10):e1304-e1313

Department of Otorhinolaryngology-Head and Neck Surgery.

Objective: To assess vestibular schwannoma (VS) practice patterns among providers.

Study Design: Cross-sectional survey.

Setting: 8th Quadrennial International Conference on Vestibular Schwannoma and Other CPA Tumors.

Subjects: Clinicians who specialize in the management of VS.

Main Outcome Measures: Responses to questions on the management and anticipated outcomes of VS for a series of common clinical scenarios were compared by specialty (otolaryngology versus neurosurgery), level of experience, scope of practice (surgery versus radiation and surgery), and geographic location of practice (United States versus international).

Results: Responses from 110 participants were analyzed. Overall, 53% of respondents were otolaryngologists, 60% had greater than 10 years of experience, and 57% practiced within the United States. In total, 86% of respondents would pursue initial observation for themselves if diagnosed with a 4 mm distal intracanalicular VS; however, practicing radiosurgeons were more likely to select stereotactic radiosurgery for this scenario compared with providers who solely practice surgery (14 versus 0%; p = 0.032). Otolaryngologists and neurosurgeons alike report that radiosurgery should not be considered a long-term hearing preservation strategy.Otolaryngologists were more optimistic regarding microsurgical hearing preservation outcomes for small distal intracanalicular tumors compared with neurosurgeons (11 versus 3% selected a high likelihood of maintaining class A/B hearing; p = 0.007). Ninety-five percent of respondents prioritized facial nerve outcome over complete disease removal in the context of microsurgical resection of large tumors.

Conclusions: Management decision-making and expected outcomes for various clinical scenarios were largely similar among providers; however, variances in several key clinical areas exist. This study points to the feasibility of developing a widely accepted consensus statement among VS experts across specialties.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1097/MAO.0000000000002887DOI Listing
December 2020

Introduction to the Special Issue, "Proceedings of the 8th Quadrennial International Conference on Vestibular Schwannoma and Other Cerebellopontine Angle Tumors".

Otol Neurotol 2020 12;41(10):e1283

Department of Otolaryngology-Head and Neck Surgery, The Otology Group of Vanderbilt University, Vanderbilt University Medical Center, Nashville, Tennessee, U.S.A.

View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1097/MAO.0000000000002889DOI Listing
December 2020

Large and small vestibular schwannomas: same, yet different tumors.

Acta Neurochir (Wien) 2021 08 20;163(8):2199-2207. Epub 2021 Jan 20.

Department of Neurologic Surgery, Mayo Clinic, 200 First St. SW, Rochester, MN, 55905, USA.

Background: Vestibular schwannomas (VS) present at variable size with heterogeneous symptomatology. Modern treatment paradigms for large VS include gross total resection, subtotal resection (STR) in combination with observation, and/or radiation to achieve optimal function preservation, whereas treatment is felt to be both easier and safer for small VS. The objective is to better characterize the presentation and surgical outcomes of large and small VS.

Methods: We collected data of patients who had surgically treated VS with a posterior fossa diameter of 4.0 cm or larger (large tumor group, LTG) and smaller than 1.0 cm in cisternal diameter (small tumor group, STG). Statistical significance was defined as p < 0.05.

Results: LTG included 48 patients (average tumor size: 44.9 mm) and STG 38 (7.9 mm). Patients in STG presented more frequently with tinnitus and sudden hearing loss. Patients in LTG underwent more STR than STG (50.0% vs. 2.6%, p < 0.0001). LTG had more complications (31.3% vs. 13.2%, p = 0.049). Postoperative facial nerve function in STG was significantly better than LTG. STG had better hearing preoperatively (p < 0.0001) and postoperatively than LTG (p = 0.0002). Postoperative headache was more common in STG (13.2% vs. 2.1%, p = 0.045). The rate of recurrence/progression needing treatment was not statistically different between the groups (12.5% in LTG vs. 7.9% in STG, p = 0.49). Those patients who required periprocedural cerebrospinal fluid diversion had higher risk of infection (20.8% vs 4.8%, p = 0.022).

Conclusion: Large and small VS present differently. LTG showed more unsatisfactory outcomes in facial nerve function and postoperative hearing despite maximal efforts undertaken toward function-preservation strategy; however, similar tumor control was achieved.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1007/s00701-021-04705-6DOI Listing
August 2021

Anterior Petrosal Approach for Enlarging Previously Radiated Recurrent Trigeminal Schwannoma: 2-Dimensional Operative Video.

Oper Neurosurg (Hagerstown) 2021 04;20(5):E353

Department of Neurosurgery, Mayo Clinic, Rochester, Minnesota.

Trigeminal nerve schwannomas (TNSs) are rare lesions that typically present with symptoms of trigeminal neuropathy or other cranial nerve palsies. These lesions classically have a dumbbell shape, with an anterior component within Meckel's cave and posterior component extending into the posterior fossa through the porus trigeminus. Surgical resection of TNSs can often be achieved via an extradural subtemporal approach to Meckel's cave without an anterior petrousectomy, even for tumors with a significant posterior fossa component, as the tumor often erodes a portion of the petrous apex.1 We present the case of a 53-yr-old female presenting to our institution with complete trigeminal neuropathy secondary to a right-sided, previously resected and radiated TNS. Serial imaging demonstrated an interval growth of significant residual tumor despite multiple adjuvant therapies, and, thus, the patient was recommended to undergo additional surgical resection. The lesion was approached through a right-sided subtemporal approach to Meckel's cave,2 with a plan to utilize an anterior petrousectomy only if difficulty resecting the posterior fossa component of the tumor was encountered. Intraoperatively, the posterior fossa component was found to be densely adherent to the adjacent brainstem, likely secondary to prior surgery and radiation therapy, and, thus, an anterior petrousectomy was performed. Postoperatively, the patient had stable trigeminal neuropathy without any new neurological deficits and a magnetic resonance imaging (MRI) confirmed a gross total resection. In the accompanying video, we hope to demonstrate the steps and nuances of both the subtemporal approach to accessing Meckel's cave and anterior petrousectomy when employed for the resection of TNSs. The patient in question provided formal consent for the making of this video.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1093/ons/opaa418DOI Listing
April 2021

Prospective Study of Disease-Specific Quality-of-Life in Sporadic Vestibular Schwannoma Comparing Observation, Radiosurgery, and Microsurgery.

Otol Neurotol 2021 02;42(2):e199-e208

Department of Otolaryngology-Head and Neck Surgery.

Background: Previous cross-sectional studies analyzing quality of life (QOL) outcomes in patients with sporadic vestibular schwannoma (VS) have shown surprisingly little difference among treatment modalities. To date, there is limited prospective QOL outcome data available comparing baseline to posttreatment scores.

Study Design: Prospective longitudinal study using the disease-specific Penn Acoustic Neuroma Quality of Life (PANQOL) scale.

Setting: Large academic skull base center.

Patients: Patients diagnosed with unilateral VS who completed a baseline survey before treatment and at least one posttreatment survey.

Main Outcome Measures: Change in PANQOL scores from baseline to most recent survey.

Results: A total of 244 patients were studied, including 78 (32%) who elected observation, 118 (48%) microsurgery, and 48 (20%) stereotactic radiosurgery. Patients who underwent microsurgery were younger (p < 0.001) and had larger tumors (p < 0.001) than those who underwent observation or radiosurgery; there was no significant difference in duration of follow-up among management groups (mean 2.1 yrs; p = 0.28). When comparing the total PANQOL score at baseline to the most recent survey, the net change was only -1.1, -0.1, and 0.3 points on a 100-point scale for observation, microsurgery, and radiosurgery, respectively (p = 0.89). After multivariable adjustment for baseline features, there were no statistically significant changes when comparing baseline to most recent scores within each management group for facial function, general health, balance, hearing loss, energy, and pain domains or total score. However, the microsurgical group experienced a 10.8-point improvement (p = 0.002) in anxiety following treatment, compared with 1.5 (p = 0.73) and 5.3 (p = 0.31) for observation and radiosurgery, respectively.

Conclusions: In this prospective longitudinal study investigating differences in QOL outcomes among VS treatment groups using the disease-specific PANQOL instrument, treatment did not modify QOL in most domains. Microsurgery may confer an advantage with regard to patient anxiety, presumably relating to the psychological benefit of "cure" from having the tumor removed.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1097/MAO.0000000000002863DOI Listing
February 2021

Beyond the ABCs: Hearing Loss and Quality of Life in Vestibular Schwannoma.

Mayo Clin Proc 2020 11;95(11):2420-2428

Department of Neurologic Surgery, Mayo Clinic, Rochester, MN; Department Otolaryngology-Head and Neck Surgery, Mayo Clinic, Rochester, MN. Electronic address:

Objective: To assess the impact of differential hearing loss on QOL in sporadic unilateral vestibular schwannoma.

Patients And Methods: Cross-sectional observational multicenter study including 422 patients with vestibular schwannoma and formal audiometry within 1 year of survey administration, analyzed using multivariable regression.

Results: Among 422 patients included, the median age was 57 (range, 18-81) years; 223 (53%) were women. Among 390 patients with complete audiometric data, American Academy of Otolaryngology-Head and Neck Surgery class was A in 134 (34%), B in 69 (18%), C in 26 (7%), and D in 161 (41%). A total of 335 of 390 (86%) reported subjective ipsilateral hearing loss (median severity, 6/10 [1 = normal, 10 = deaf]), 166 (43%) reported ipsilateral inability to use the telephone, 155 (37%) reported that hearing loss had affected personal relationships, and 213 (51%) reported difficulty with conversations. After adjusting for age and sex, the odds ratio (OR) for hearing loss adversely affecting relationships was 4.4 for class B hearing vs class A (95% CI, 2.1-9.4; P<.0001). The OR for difficulty with conversations was 2.7 for class B vs class A (95% CI, 1.4-5.3; P=.003). The OR for lost ipsilateral telephone use was 6.3 for class B vs class A (95% CI, 3.2-13.0; P<.0001). Differences between class B and class C were not significant. WRS outperformed PTA as a predictor of hearing-related QOL. The optimal threshold for predicting a significant adverse impact on QOL was WRS less than 72% to 76%.

Conclusion: Hearing loss adversely affects QOL after only modest audiometric disability. The WRS alone appears to be a much more reliable predictor of hearing-related QOL than PTA or American Academy of Otolaryngology-Head and Neck Surgery class.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.mayocp.2020.03.033DOI Listing
November 2020

Surgery versus radiosurgery for facial nerve schwannoma: a systematic review and meta-analysis of facial nerve function, postoperative complications, and progression.

J Neurosurg 2020 Oct 30:1-12. Epub 2020 Oct 30.

Departments of1Neurosurgery.

Objective: Intracranial facial nerve schwannomas (FNS) requiring treatment are frequently recommended for surgery or stereotactic radiosurgery (SRS). The objective of this study was to compare facial nerve function outcomes between these two interventions for FNS via a systematic review and meta-analysis.

Methods: A search of the Ovid EMBASE, PubMed, SCOPUS, and Cochrane databases from inception to July 2019 was conducted following PRISMA guidelines. Articles were screened against prespecified criteria. Facial nerve outcomes were classified as improved, stabilized, or worsened by last follow-up. Incidence was pooled by random-effects meta-analysis of proportions.

Results: Thirty-three articles with a pooled cohort of 519 patients with FNS satisfied all criteria. Twenty-five articles described operative outcomes in 407 (78%) patients; 10 articles reported SRS outcomes in 112 (22%). In the surgical cohort, facial nerve function improved in 23% (95% CI 15%-32%), stabilized in 41% (95% CI 32%-50%), and worsened in 30% (95% CI 21%-40%). In the SRS cohort, facial nerve function was improved in 20% (95% CI 9%-34%), stable in 66% (95% CI 54%-78%), and worsened in 9% (95% CI 3%-16%). Compared with SRS, microsurgery was associated with a significantly lower incidence of stable facial nerve function (p < 0.01) and a significantly higher incidence of worsened facial nerve function (p < 0.01). Tumor progression and complication rates were comparable. Outcome certainty assessments were very low to moderate for all parameters.

Conclusions: Unfavorable facial nerve function outcomes are associated with surgical treatment of intracranial FNS, whereas stable facial nerve function outcomes are associated with SRS. Therefore, SRS should be recommended to patients with FNS who require treatment, and surgery should be reserved for patients with another indication, such as decompression of the brainstem. Further study is required to definitively optimize and validate management strategies for these rare skull base tumors.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3171/2020.6.JNS201548DOI Listing
October 2020

Cochlear Implants and Magnetic Resonance Imaging: Experience With Over 100 Studies Performed With Magnets in Place.

Otol Neurotol 2021 01;42(1):51-58

Department of Otorhinolaryngology.

Objective: To evaluate adverse events and feasibility of performing 1.5-T MRI in patients with cochlear implants (CI) and auditory brainstem implants (ABI).

Setting: Single tertiary academic referral center.

Patients: CI and ABI recipients undergoing 1.5-T MRI without internal magnet removal.

Intervention(s): MRI after tight headwrap application.

Main Outcome Measures: Adverse events, patient tolerance.

Results: A total of 131 MR studies in 79 patients were performed, with a total of 157 study ears. Sixty-one patients (77%) had unilateral devices. Four patients (5%) underwent MRI with ABI magnets in place. Sixteen patients (20%) had MRI-compatible devices that did not require a head wrap. There were no instances of device stimulation, device malfunction, or excessive heating of the receiver-stimulator package. Magnet tilt requiring manual repositioning occurred during seven studies (4.5%) and magnet displacement requiring operative intervention occurred during seven studies (4.5%). Significant pain where imaging had to be discontinued occurred during three episodes (2%). No adverse events were noted among patients who underwent MRI with an MRI-compatible magnet.

Conclusions: MRI with CI or ABI magnets in place is associated with a low prevalence of adverse events when performed in a controlled setting. Many partial magnet displacements can be corrected with firm manual pressure. Devices with magnets that align with the field within their housing were not associated with any adverse events and do not require immobilization of the magnet during the scan. These may be valuable in patients with known or anticipated need for MRI.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1097/MAO.0000000000002866DOI Listing
January 2021

Natural History of Growing Sporadic Vestibular Schwannomas: An Argument for Continued Observation Despite Documented Growth in Select Cases.

Otol Neurotol 2020 10;41(9):e1149-e1153

Department of Otolaryngology-Head and Neck Surgery, Mayo Clinic, Rochester, Minnesota.

Objective: Definitive treatment of sporadic vestibular schwannoma (VS) following documented growth is common practice at most centers in the United States. However, as a natural extension of this paradigm, very little evidence exists surrounding the natural history of growing tumors. The primary objective of the current work was to describe the natural history of sporadic VS following documentation of initial tumor growth.

Study Design: Retrospective cohort study.

Setting: Tertiary referral center.

Patients: Patients diagnosed with sporadic VS between January 1, 2001 and December 31, 2015 who elected continued observation despite having volumetric growth ≥20% of original tumor volume on interval magnetic resonance imaging (MRI).

Main Outcome Measure: Survival free of subsequent volumetric growth.

Results: Of 361 patients undergoing observation with serial imaging during the study period, 85 patients met inclusion criteria at a median age of 66 years (interquartile ranges [IQR] 55-71). Within this cohort, 40 patients demonstrated subsequent volumetric growth at a median of 1.7 years (IQR 1.0-2.6) from the date of initial MRI that documented growth. The median volumetric growth was 43% (IQR 28-57), and the median growth rate was 0.026 cm per year (IQR 0.009-0.107). Survival free of subsequent volumetric growth rates (95% CI; number still at risk) at 1, 2, 3, 4, and 5 years were 93% (87-99; 75), 67% (58-79; 45), 54% (43-67; 29), 44% (33-59; 19), and 41% (30-56; 12), respectively.

Conclusions: In a cohort exclusively comprised of sporadic VS with documented growth, over 40% of tumors demonstrated no subsequent volumetric growth after 5 years of continued MRI surveillance. These data challenge the supposition that once growth occurs, all tumors will exhibit sustained growth. Continued observation after documented growth of sporadic VS is a reasonable consideration in appropriately selected cases.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1097/MAO.0000000000002756DOI Listing
October 2020

Increase in cochlear implant electrode impedances with the use of electrical stimulation.

Int J Audiol 2020 11 4;59(11):881-888. Epub 2020 Aug 4.

Department of Otolaryngology-Head and Neck Surgery, Mayo Clinic School of Medicine, Rochester, MN, USA.

Objective: Electrode impedances play a critical role in cochlear implant programming. It has been previously shown that impedances rise during periods of non-use, such as the post-operative recovery period. Then when the device is activated and use is initiated, impedances fall and are typically stable. In this study, we report a new pattern where electrode impedances increase with device use and decrease with device rest.

Design: Electrode impedances were measured three to four times every day over a span of 1-3 months for two cochlear implant patients.

Study Sample: Two patients with a Nucleus cochlear implant participated in this study.

Results: Both subjects in this study show wide fluctuations in electrode impedances. By taking serial electrode impedance measurements throughout a day of use, we observe that electrode impedances consistently increase with device use and decrease with device rest.

Conclusion: In this study, we report two cases of electrode impedances increasing as a function of device use. Numerous management strategies were employed to reduce this effect but none prevailed; a clear pathophysiologic mechanism remains elusive. Further study into the cause of this electrode impedance pattern is warranted to establish a management strategy for these cochlear implant users.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1080/14992027.2020.1799251DOI Listing
November 2020

The Influence of Vestibular Schwannoma Tumor Volume and Growth on Hearing Loss.

Otolaryngol Head Neck Surg 2020 Apr 28;162(4):530-537. Epub 2020 Jan 28.

Department of Otolaryngology-Head and Neck Surgery, Mayo Clinic, Rochester, Minnesota, USA.

Objective: To ascertain the relationship among vestibular schwannoma (VS) tumor volume, growth, and hearing loss.

Study Design: Retrospective cohort study.

Setting: Single tertiary center.

Subjects And Methods: Adults with observed VS and serviceable hearing at diagnosis were included. The primary outcome was the development of nonserviceable hearing as estimated using the Kaplan-Meier method. Associations of tumor volume with baseline hearing were assessed using Spearman rank correlation coefficients. Associations of volume and growth with the development of nonserviceable hearing over time were assessed using Cox proportional hazards models and summarized with hazard ratios (HRs).

Results: Of 230 patients with VS and serviceable hearing at diagnosis, 213 had serial volumetric tumor data for analysis. Larger tumor volume at diagnosis was associated with increased pure-tone average (PTA) ( < .001) and decreased word recognition score (WRS) ( = .014). Estimated rates of maintaining serviceable hearing at 6 and 10 years following diagnosis were 67% and 49%, respectively. Larger initial tumor volume was associated with development of nonserviceable hearing in a univariable setting (HR for 1-cm increase: 1.36, = .040) but not after adjusting for PTA and WRS. Tumor growth was not significantly associated with time to nonserviceable hearing (HR, 1.57; = .14), although estimated rates of maintaining serviceable hearing during observation were poorer in the group that experienced growth.

Conclusion: Larger initial VS tumor volume was associated with poorer hearing at baseline. Larger initial tumor volume was also associated with the development of nonserviceable hearing during observation in a univariable setting; however, this association was not statistically significant after adjusting for baseline hearing status.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1177/0194599819900396DOI Listing
April 2020

Durability of Hearing Preservation Following Microsurgical Resection of Vestibular Schwannoma.

Otol Neurotol 2019 12;40(10):1363-1372

Department of Otolaryngology-Head and Neck Surgery.

Objective: To ascertain long-term hearing outcomes in patients with serviceable hearing following microsurgical resection of sporadic vestibular schwannoma (VS).

Study Design: Retrospective cohort.

Setting: Tertiary academic referral center.

Patients: Forty-three adult subjects with unilateral sporadic VS who had serviceable hearing (American Academy of Otolaryngology-Head and Neck Surgery [AAO-HNS] class A or B) on initial postoperative audiogram following microsurgical resection between 2003 and 2016 with a minimum of two postoperative audiograms available for review.

Intervention: Surgical treatment with a retrosigmoid or middle cranial fossa approach.

Main Outcome Measure: Rate of maintaining serviceable hearing, as estimated using the Kaplan-Meier method, in accordance with the 1995 and 2012 AAO-HNS guidelines on reporting hearing outcomes.

Results: The median immediate postoperative pure-tone average (PTA) and word recognition score (WRS) were 31 dB and 95%, respectively. At last follow-up, the median PTA was 38 dB with a median change of 5 dB from initial postoperative audiogram, and the median WRS was 90% with a median change of 0% from initial postoperative audiogram. Eight patients developed non-serviceable hearing at a median of 4.1 years following microsurgical resection (interquartile range, 2.9-7.0). The median duration of hearing follow-up for the 35 patients who maintained serviceable hearing was 3.1 years (interquartile range, 2.2-7.5). Tumor control was achieved in 41 (95%) patients. The rate of maintaining serviceable hearing at 5 years was 81%.

Conclusion: Microsurgical resection provides excellent tumor control and durable long-term hearing in those with AAO-HNS class A or B hearing postoperatively. The paradigm of proactive microsurgical resection-when the tumor is small and hearing is good-hinges on the surgeon's ability to preserve residual hearing in a very high percentage of cases at or near preoperative hearing levels to maintain an advantage over conservative observation with regard to long-term hearing preservation.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1097/MAO.0000000000002378DOI Listing
December 2019

Multi-frequency Electrocochleography Measurements can be Used to Monitor and Optimize Electrode Placement During Cochlear Implant Surgery.

Otol Neurotol 2019 12;40(10):1287-1291

Department of Otolaryngology-Head and Neck Surgery, Mayo Clinic School of Medicine, Rochester, Minnesota.

Objective: To report the use of multi-frequency intra-cochlear electrocochleography (ECOG) in monitoring and optimizing electrode placement during cochlear implant surgery. An acoustic pure tone complex comprising of 250, 500, 1000, and 2000 Hz was used to elicit ECOG, or more specifically cochlear microphonics (CMs), responses from various locations in the cochlea. The most apical cochlear implant electrode was used as the recording electrode.

Study Design: Clinical capsule report.

Setting: Tertiary academic referral center.

Results: ECOG measurements were performed during cochlear implant surgery in an adult patient with significant residual acoustic hearing. The 500, 1000, and 2000 Hz CM tracings from the most apical electrode showed an amplitude peak at three different instances during the early phase of cochlear implant electrode insertion. These results are consistent with the tonotopic organization of the cochlea. During final electrode placement a slight advancement of the electrode array resulted in a correlated decrease in 250, 500, and/or 1000 Hz CM amplitude. The electrode array was retracted and repositioned which resulted in a recovery of CM amplitude. Intraoperative CM thresholds revealed a correlation of r = 0.87 with preoperative audiometric thresholds.

Conclusion: We present a report on simultaneous multi-frequency ECOG monitoring during cochlear implant surgery. Multi-frequency ECOG can be used to differentiate between electrode trauma and the advancement of the apical electrode beyond the CM source in the cochlea.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1097/MAO.0000000000002406DOI Listing
December 2019

Rate of Initial Hearing Loss During Early Observation Predicts Time to Non-Serviceable Hearing in Patients With Conservatively Managed Sporadic Vestibular Schwannoma.

Otol Neurotol 2019 12;40(10):e1012-e1017

Department of Otolaryngology, University of Texas Southwestern Medical Center, Dallas, Texas.

Objective: To date, prediction models for estimating risk of acquiring non-serviceable hearing in subjects with observed vestibular schwannoma (VS) have evaluated outcomes primarily based on features at initial diagnosis. Herein, we evaluate the association of rate of hearing decline during the initial period of observation with time to non-serviceable hearing. If significant, rate of hearing decline may inform decision making after an introductory period of observation.

Setting: Two tertiary care centers.

Patients: VS patients with serviceable hearing who underwent at least three audiograms and two magnetic resonance imaging (MRI) studies before intervention or being lost to follow-up. The rate of change in pure-tone average (PTA) and word recognition score (WRS) was calculated as the score from the second audiogram minus the score from the first audiogram, divided by the duration in months between the two.

Main Outcome Measure(s): Serviceable hearing, defined as PTA ≤50 dB HL and WRS ≥50%.

Results: Among 266 patients meeting inclusion criteria, 52 developed non-serviceable hearing at last follow-up. Kaplan-Meier estimated rates of maintaining serviceable hearing (95% CI; number still at risk) at 1, 3, 5, 7, and 10 years were 97% (95-100; 206), 78% (72-85; 98), 68% (60-77; 39), 60% (50-73; 17), and 44% (29-67; 2), respectively. In a univariable setting, each 1 dB increase per month in the rate of initial PTA change was associated with a 96% increased likelihood of acquiring non-serviceable hearing (hazard ratio [HR] 1.96; 95% CI 1.44-2.68; p < 0.001). Each 1% increase per month in the rate of initial WRS change was associated with a decreased likelihood of acquiring non-serviceable hearing (hazard ratio [HR] 0.79; 95% confidence interval [CI] 0.66-0.94; p = 0.009). After multivariable adjustment, both rate of PTA change (HR 2.42; 95% CI 1.72-3.41; p < 0.001) and rate of WRS change (HR 0.81; 95% CI 0.67-0.99; p = 0.043) remained statistically significantly associated with time to non-serviceable hearing.

Conclusion: Rate of early PTA and WRS decline during the initial period of observation are significantly associated with time to development of non-serviceable hearing. This information may facilitate accurate patient counseling and inform decision-making regarding prospective disease management.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1097/MAO.0000000000002390DOI Listing
December 2019

Predominance of M1 subtype among tumor-associated macrophages in phenotypically aggressive sporadic vestibular schwannoma.

J Neurosurg 2019 Oct 4:1-9. Epub 2019 Oct 4.

Departments of1Neurologic Surgery.

Objective: Tumor-associated macrophages (TAMs) have been implicated as pathologic actors in phenotypically aggressive vestibular schwannoma (VS), potentially mediated via programmed death-ligand 1 (PD-L1). The authors hypothesized that PD-L1 is a key regulator of the VS immune microenvironment.

Methods: Forty-six consecutive, radiation-naïve, sporadic VSs that were subtotally resected at primary surgery were assessed via immunohistochemical analysis, including analysis of CD163 and PD-L1 expression. Pathologic data were correlated with clinical endpoints, including tumor control, facial nerve function, and complications.

Results: Baseline parameters were equivalent between stable and progressive post-subtotal resection (STR) VS. CD163 percent positivity and M2 index were significantly increased among tumors that remained stable (34% vs 21%, p = 0.02; 1.13 vs 0.99, p = 0.0008), as well as patients with favorable House-Brackmann grade I or II facial nerve function (31% vs 13%, p = 0.04; 1.11 vs 0.97, p = 0.05). PD-L1 percent positivity was significantly associated with tumor progression (1% vs 11%, p = 0.01) and unfavorable House-Brackmann grade III-VI facial nerve function (1% vs 38%, p = 0.02). On multivariate analysis, PD-L1 was independently significant in all models (likelihood ratio 4.4, p = 0.04), while CD163 was dependent in all iterations.

Conclusions: In contrast to prior reports, in this study, the authors observed significantly increased levels of M1, CD163+ TAMs in association with VS that progressed after STR. Progressive tumors are characterized by increased PD-L1, potentially highlighting a mechanism of immune evasion that results in TAM deactivation, tumor growth, and further infiltration of anti-tumor immune cells. Targeting PD-1/PD-L1 may offer therapeutic promise, particularly in the setting of disease control after STR.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3171/2019.7.JNS19879DOI Listing
October 2019

Involvement of the Cochlear Aqueduct by Jugular Paraganglioma Is Associated With Sensorineural Hearing Loss.

Otol Neurotol 2019 10;40(9):1230-1236

Department of Otolaryngology-Head and Neck Surgery.

Objective: The etiology of sensorineural hearing loss (SNHL) in patients with jugular paraganglioma (JP) whose tumors lack inner ear fistulae or vestibulocochlear nerve involvement is unknown. Recent literature has proposed that occlusion of the inferior cochlear vein may be causative. Herein, we assess the association between radiologic involvement of the cochlear aqueduct (CA) and the development of SNHL.

Study Design: Blinded, retrospective review of imaging and audiometry.

Setting: Tertiary center.

Patients: Adults with JP.

Intervention(s): None.

Main Outcome Measures: Asymmetric SNHL was assessed continuously as the difference in bone conduction pure-tone average (BCPTA) between ears and as a categorical variable (≥15 dB difference at two consecutive frequencies, or a difference in speech discrimination score of ≥15%). Involvement of the CA was considered present if there was evidence of medial T2 fluid signal loss, contrast enhancement, or bony erosion/expansion.

Results: Of 30 patients meeting inclusion criteria, 15 (50%) had asymmetric SNHL. CA involvement was observed in 87% of patients with asymmetric SNHL compared with 13% in those with symmetric hearing (p = 0.0001). Univariate analysis demonstrated that age, sex, and tumor volume were not associated with asymmetric SNHL. The median difference in BCPTA between ears in patients with CA involvement was 21.3 dB HL compared to 1.2 dB HL in those without CA involvement (p < 0.0001). Regression analysis demonstrates that enhancement within the CA is associated with a BCPTA difference of 19.4 dB HL (p = 0.0006).

Conclusions: Cochlear aqueduct involvement by JP is associated with SNHL in the absence of inner ear fistula, vestibulocochlear nerve involvement, or brainstem compression. Correlation with operative findings or histopathologic evidence of tumor involvement may validate this intriguing imaging finding.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1097/MAO.0000000000002346DOI Listing
October 2019

Beyond the Learning Curve: Comparison of Microscopic and Endoscopic Incidences of Internal Carotid Injury in a Series of Highly Experienced Operators.

World Neurosurg 2019 Nov 15;131:e128-e135. Epub 2019 Jul 15.

Department of Neurologic Surgery, Mayo Clinic, Rochester, Minnesota, USA. Electronic address:

Background: As the endoscopic endonasal approach (EEA) has gained popularity as an alternative to microsurgery (MS) for transsphenoidal resection (TSR), numerous studies have attempted to assess the differential risk of internal carotid artery (ICA) injury between the techniques, yet results have been equivocal and contradictory. The aim of this study was to evaluate ICA injury in MS versus EEA among highly experienced neurosurgeons.

Methods: We performed a systematic literature review of publications from 2002-2017 reporting ICA injury outcomes in ≥250 cases using MS or EEA.

Results: Seventeen series reporting 11,149 patients were included: 3 MS series, 13 EEA series, and 1 series with adequate samples for each. ICA injury incidences were 0.0%-1.6% in cohorts of 275-3000. MS series documented 5 ICA injuries in 2672 operations, for an overall incidence of 0.2% (range, 0.0%-0.4%), and EEA series reported 30 ICA injuries in 8477 operations, for a 0.4% injury rate (range, 0.0%-1.6%); the difference was nonsignificant (P = 0.25). Increased operative experience was associated with decreased incidence of ICA injury, a finding preserved in the overall study cohort and within discretely examined MS and EEA subgroups (overall r = 0.08, MS r = 0.23, EEA r = 0.07).

Conclusions: ICA injury is the most serious complication of TSR of pituitary neoplasms. Operator inexperience may be a more important risk factor than choice of surgical technique, given the comparably low rates of injury obtained by highly experienced surgeons independent of technique. This emphasizes the need for consolidated care in pituitary centers of excellence, improvement of high-fidelity simulators, and skull base mentorship between senior and junior staff.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.wneu.2019.07.074DOI Listing
November 2019

Anatomical Step-by-Step Dissection of Complex Skull Base Approaches for Trainees: Surgical Anatomy of the Posterior Petrosal Approach.

J Neurol Surg B Skull Base 2019 Aug 9;80(4):338-351. Epub 2018 Oct 9.

Department of Neurologic Surgery, Mayo Clinic, Rochester, Minnesota, United States.

 Although numerous anatomical and operative atlases have been published, those that have focused on the skull base either have provided views that are quite difficult to achieve in the operating room to better depict surgical anatomy or are written at the level of an audience with considerable knowledge and experience.  Five sides of three formalin-fixed latex-injected specimens were dissected under microscopic magnification. A posterior petrosectomy approach was performed by three neurosurgical residents at different training levels with limited previous experience in anatomical dissection mentored by the senior authors (C. L. W. D. and M. J. L.) and a clinical skull base fellow with additional anatomical dissection experience (M. P. C.). Anatomical dissections were performed until the expected level of dissection quality was achieved to demonstrate each important step of the surgical approach that would be understandable to all trainees of all levels. Following dissection education, representative case applications were reviewed.  The posterior petrosectomy (also known as presigmoid retrolabyrinthine approach) affords excellent access to cranial nerves III to XI and a diverse array of pathologies. Key steps include positioning and skin incision, scalp and muscle flaps, burr holes, craniotomy flap elevation, superficial mastoidectomy, otic capsule exposure and presigmoid dura decompression, primary presigmoid durotomy, inferior temporal durotomy, superior petrosal sinus ligation, tentorium sectioning, and final exposure.  The posterior petrosectomy is a challenging approach; thorough operative-style laboratory dissection is essential to provide trainees with a suitable guide. We describe a comprehensive approach to learning this technique, intended to be understandable and usable by a resident audience.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1055/s-0038-1675174DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6635129PMC
August 2019

Retrosigmoid Approach for Resection of Large Cystic Vestibular Schwannoma.

J Neurol Surg B Skull Base 2019 Jun 26;80(Suppl 3):S285. Epub 2019 Feb 26.

Department of Neurologic Surgery, Mayo Clinic, Rochester, Minnesota, United States.

 This video was aimed to describe the surgical indications, relevant anatomy, and surgical steps of retrosigmoid approach for resection of a large cystic vestibular schwannoma (VS).  The operative steps are described in a surgical instructional video.  The surgery took place at a tertiary skull base referral center.  Patient is a 62-year-old man who reported with right sided profound hearing loss with no word recognition, progressive dizziness and tinnitus, excruciating burning pain in the V2 distribution of right trigeminal nerve, wide-based gait, and a right cerebellopontine angle (CPA) cystic VS measuring 3.3 cm.  The large cystic VS was resected through retrosigmoid approach.  The surgery resulted in removal of the large cystic VS with initial delayed facial weakness that completely resolved (House Brackmann grade 1) by 3 month follow-up. The patient had no other postoperative complications and is convalescing well from the procedure.  Cystic VS presents some unique challenges compared with their solid counterparts. The cystic tumor capsule may be very adherent to the adjacent structures, and distinguishing thin cyst walls from the arachnoid of the CPA, can be quite challenging. The retrosigmoid approach provides adequate surgical exposure for VS tumor resection. The link to the video can be found at: https://youtu.be/sFNvRWG465Q .
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1055/s-0039-1677850DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6534657PMC
June 2019

Retrosigmoid Approach for Resection of Medium-Sized Vestibular Schwannoma.

J Neurol Surg B Skull Base 2019 Jun 4;80(Suppl 3):S284. Epub 2019 Mar 4.

Department of Neurologic Surgery, Mayo Clinic, Rochester, Minnesota, United States.

 This video was aimed to describe the relevant anatomy and key surgical steps of retrosigmoid approach for gross total resection of a medium-sized vestibular schwannoma (VS).  The procedure is described in a surgical instructional video.  The surgery took place at a tertiary skull base referral center.  Patient is a 63-year-old woman who reported with nonserviceable hearing (Pure Tone Average 60 dB Hearing level, Word Recognition Score 45%), occasional tinnitus, and a VS in the left cerebellopontine angle (CPA), extending into internal auditory canal (IAC), measuring 1.7 cm parallel to the petrous temporal bone.  The VS was resected by retrosigmoid approach.  The surgery results gross total resection of the VS with postoperative House-Brackmann grade 1 facial nerve function and no postoperative complications.  The retrosigmoid approach is a good strategy to remove VS involving the CPA and the IAC. The link to the video can be found at: https://youtu.be/B6K_UkrKitg .
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1055/s-0039-1677848DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6534658PMC
June 2019

For Whom the Bell's Toll: Recurrent Facial Nerve Paralysis, A Retrospective Study and Systematic Review of the Literature.

Otol Neurotol 2019 04;40(4):517-528

Department of Otorhinolaryngology.

Purpose: To examine the etiology, clinical course, and management of recurrent peripheral facial nerve paralysis.

Methods: Retrospective review at a single tertiary academic center and systematic review of the literature. Clinical presentation, laboratory and imaging findings, treatment and outcome for all cases of recurrent ipsilateral, recurrent contralateral, and bilateral simultaneous cases of facial paralysis are reviewed.

Results: Between 2000 and 2017, 53 patients [41.5% men, 29 median age of onset (range 2.5 wk-75 yr)] were evaluated for recurrent facial nerve paralysis at the authors' institution. Twenty-two (41.5%) cases presented with ipsilateral recurrences only, while the remaining 31 patients (58.5%) had at least 1 episode of contralateral recurrent paralysis. No cases of bilateral simultaneous facial nerve paralysis were observed. The median number of paretic events for all patients was 3 (range 2-20). The median nadir House-Brackmann score was 4, with a median recovery to House-Brackmann grade 1.5 over a mean recovery time of 61.8 days (range 1-420 d). Diagnostic evaluation confirmed Melkersson-Rosenthal syndrome in four (7.5%) cases, neurosarcoidosis in two (3.7%), traumatic neuroma in one (1.9%), Ramsay Hunt syndrome in one (1.9%), granulomatosis with polyangiitis in one (1.9%), and neoplastic causes in three (5.7%) cases [facial nerve schwannoma (n = 2; 3.7%), metastatic squamous cell carcinoma to the deep lobe of the parotid gland (n = 1; 1.9%)]; ultimately, 77.4% (41) of cases were deemed idiopathic. Facial nerve decompression via a middle cranial fossa approach was performed in three (5.7%) cases without subsequent episodes of paralysis.

Conclusion: Recurrent facial nerve paralysis is uncommon and few studies have evaluated this unique population. Recurrent ipsilateral and contralateral episodes are most commonly attributed to idiopathic facial nerve paralysis (i.e., Bell's palsy); however, a subset harbor neoplastic causes or local manifestations of underlying systemic disease. A comprehensive diagnostic evaluation is warranted in patients presenting with recurrent facial nerve paralysis and therapeutic considerations including facial nerve decompression can be considered in select cases.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.1097/MAO.0000000000002167DOI Listing
April 2019

Key anatomical landmarks for middle fossa surgery: a surgical anatomy study.

J Neurosurg 2018 Nov 1:1-10. Epub 2018 Nov 1.

Departments of1Neurologic Surgery and.

OBJECTIVEMiddle fossa surgery is challenging, and reliable surgical landmarks are essential to perform accurate and safe surgery. Although many descriptions of the middle fossa components have been published, a clinically practical description of this very complex anatomical region is lacking. Small structure arrangements in this area are often not well visualized or accurately demarcated with neuronavigation systems. The objective is to describe a "roadmap" of key surgical reference points and landmarks during middle fossa surgery to help the surgeon predict where critical structures will be located.METHODSThe authors studied 40 dry skulls (80 sides) obtained from the anatomical board at their institution. Measurements of anatomical structures in the middle fossa were made with a digital caliper and a protractor, taking as reference the middle point of the external auditory canal (MEAC). The results were statistically analyzed.RESULTSThe petrous part of the temporal bone was found at a mean of 16 mm anterior and 24 mm posterior to the MEAC. In 87% and 99% of the sides, the foramen ovale and foramen spinosum, respectively, were encountered deep to the zygomatic root. The posterior aspect of the greater superficial petrosal nerve (GSPN) groove was a mean of 6 mm anterior and 25 mm medial to the MEAC, nearly parallel to the petrous ridge. The main axis of the IAC projected to the root of the zygoma in all cases. The internal auditory canal (IAC) porus was found 5.5 mm lateral and 4.5 mm deep to the lateral aspect of the trigeminal impression along the petrous ridge (mean measurement values). A projection from this point to the middle aspect of the root of the zygoma, being posterior to the GSPN groove, could estimate the orientation of the IAC.CONCLUSIONSIn middle fossa approaches, the external acoustic canal is a reliable reference before skin incision, whereas the zygomatic root becomes important after the skin incision. Deep structures can be related to these 2 anatomical structures. An easy method to predict the location of the IAC in surgery is described. Careful study of the preoperative imaging is essential to adapt this knowledge to the individual anatomy of the patient.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3171/2018.5.JNS1841DOI Listing
November 2018

Long-term tumor control following stereotactic radiosurgery for jugular paraganglioma using 3D volumetric segmentation.

J Neurosurg 2018 Apr 1:1-9. Epub 2018 Apr 1.

Departments of1Otorhinolaryngology.

OBJECTIVEThe morbidity of gross-total resection of jugular paraganglioma (JP) is often unacceptable due to the potential for irreversible lower cranial neuropathy. Stereotactic radiosurgery (SRS) has been used at the authors' institution since 1990 for the treatment of JP and other benign intracranial tumors. Conventional means of assessing tumor progression using linear measurements or elliptical approximations are imprecise due to the irregular shape and insinuating growth pattern of JP. The objective of this study was to assess long-term tumor control in these patients by using slice-by-slice 3D volumetric segmentation of serial MRI data.METHODSRadiographic data and clinical records were reviewed retrospectively at a single, tertiary-care academic referral center for patients treated from 1990 to 2017. Volumetric analyses by integration of consecutive tumor cross-sectional areas (tumor segmentation) of serial MRI data were performed. Tumor progression was defined as volumetric growth of 15% or greater over the imaging interval. Primary outcomes analyzed included survival free of radiographic and clinical progression. Secondary outcomes included new or worsened cranial neuropathy.RESULTSA total of 85 patients were treated with Gamma Knife radiosurgery (GKRS) for JP at the authors' institution over the last 27 years. Sixty patients had pretreatment and serial posttreatment contrast-enhanced MRI follow-up suitable for volumetric analysis. A total of 214 MR images were analyzed to segment tumor images in a slice-by-slice fashion to calculate integral tumor volume. The median follow-up duration was 66 months (range 7-202 months). At 5 years the tumor progression-free survival rate was 98%. Three tumors exhibited progression more than 10 years after GKRS. Estimated survival free of radiographic progression rates (95% confidence interval [CI]; n = number still at risk) at 5, 10, and 15 years following radiosurgery were 98% (95% CI 94%-100%; n = 34), 94% (95% CI 85%-100%; n = 16), and 74% (95% CI 56%-98%; n = 6), respectively. One patient with tumor progression required treatment intervention using external beam radiation therapy, constituting the only case of clinical progression. Two patients (3%) without preexisting lower cranial nerve dysfunction developed new ipsilateral vocal fold paralysis following radiosurgery.CONCLUSIONSSRS achieves excellent long-term tumor control for JP without a high risk for new or worsened cranial neuropathy when used in primary, combined modality, or recurrent settings. Long-term follow-up is critical due to the potential for late radiographic progression (i.e., more than 10 years after SRS). As none of the patients with late progression have required salvage therapy, the clinical implications of this degree of tumor growth have yet to be determined.
View Article and Find Full Text PDF

Download full-text PDF

Source
http://dx.doi.org/10.3171/2017.10.JNS17764DOI Listing
April 2018
-->