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Daskalou D, Hsieh JW, Hugentobler M, Macario S, Sipione R, Voruz F, Guinand N, Senn P, Landis BN. Gustatory Function in Patients With Cerebellopontine Angle Masses. Otol Neurotol 2024; 45:798-805. [PMID: 38995723 DOI: 10.1097/mao.0000000000004240] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/14/2024]
Abstract
OBJECTIVE To investigate the impact of cerebellopontine angle (CPA) masses on subjective and measured taste function. STUDY DESIGN Retrospective cross-sectional study. SETTING Tertiary referral center. PATIENTS Consecutive adult patients with untreated CPA masses. INTERVENTIONS Gustatory function was psychophysically measured with Taste Strips (range, 0-16) on both sides of the tongue. Subjective taste complaints were assessed using a questionnaire. MAIN OUTCOME MEASURES Half-sided taste impairment (hemi-ageusia) was defined as side-to-side asymmetry ≥4 points with <9 points on the side of the CPA mass. We used the Koos classification for vestibular schwannomas (VS) and, in the case of facial nerve palsy, the House-Brackmann grading system. RESULTS We included 135 patients (mean [standard deviation (SD)] age, 55.3 ± 14.1 yr; 62 males). The most common CPA mass was VS (77%). Overall, the measured taste function was lower on the affected compared with the healthy side of the tongue (mean score, 9.8 ± 3.3 versus 11 ± 2.9; p < 0.0001). Looking for clinically relevant one-sided taste impairment revealed 18 (13.3%) patients with hemi-ageusia, but only 4 (30.8%) of those subjectively complained of taste dysfunction. Regarding VS, Koos IV masses presented the lowest score on the affected side (mean score, 7.5 ± 3.7). Six patients presented with facial palsy. Having facial palsy did not result in a lower Taste Strips score (p = 0.23). CONCLUSION Before any CPA mass treatment, a measurable ipsilateral decrease in gustatory function is present in many patients. Most patients do not notice this preexisting taste impairment. From a medicolegal standpoint, this warrants consideration. To avoid postoperative claims regarding taste function, a preoperative assessment may be considered.
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Affiliation(s)
| | | | - Marianne Hugentobler
- Service of Otorhinolaryngology-Head and Neck Surgery, Department of Clinical Neurosciences, Geneva University Hospitals, Geneva, Switzerland
| | - Sonia Macario
- Service of Otorhinolaryngology-Head and Neck Surgery, Department of Clinical Neurosciences, Geneva University Hospitals, Geneva, Switzerland
| | - Rebecca Sipione
- The Inner Ear and Olfaction Lab, University of Geneva, Faculty of Medicine, Geneva, Switzerland
| | - François Voruz
- Service of Otorhinolaryngology-Head and Neck Surgery, Department of Clinical Neurosciences, Geneva University Hospitals, Geneva, Switzerland
| | - Nils Guinand
- Service of Otorhinolaryngology-Head and Neck Surgery, Department of Clinical Neurosciences, Geneva University Hospitals, Geneva, Switzerland
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Podlesek D, Chao YT, Weitkamp F, Schackert G, Hummel T. Trigeminal Sensory Neuropathy Predicts Chemosensory Dysfunction After Skull Base Surgery. Oper Neurosurg (Hagerstown) 2023; 24:410-416. [PMID: 36701548 DOI: 10.1227/ons.0000000000000541] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Accepted: 09/20/2022] [Indexed: 01/27/2023] Open
Abstract
BACKGROUND Trigeminal sensory neuropathy, characterized by diminished or exaggerated/painful sensation along the distribution of trigeminal branches, is one of the complications after skull base surgery. These procedures can also affect chemosensory functions and compromise the patients' quality of life. OBJECTIVE To examine those postoperative complications in chemosensory and facial cutaneous sensory functions as well as their interaction. METHODS A total of 61 patients being operated for various pathologies in the vicinity of trigeminal pathway (17 with trigeminal neuralgia, 20 with meningiomas, and 24 with vestibular schwannomas) and 50 healthy controls were enrolled in this case-control study. Postoperative trigeminal neuropathic symptoms were evaluated. The olfactory, gustatory, and intranasal trigeminal functions were assessed using the Sniffin' Stick olfactory test, lateralized taste strip test, and the lateralized intranasal trigeminal CO 2 detection thresholds, respectively. RESULTS Patients with trigeminal neuralgia and meningioma had relatively decreased olfactory function, whereas those with vestibular schwannoma had a relative decrease in taste function. As for the relationship between the distribution of trigeminal neuropathy and chemosensory dysfunction, we found that V3 involvement predicted lower side-specific taste function. In addition, V2/V3 involvement predicted relatively lower side-specific intranasal trigeminal function. CONCLUSION The present results suggest a differential involvement of the chemical senses in relation to the site and pathology of the lesions after surgery. The presence of trigeminal neuropathy is associated with taste and intranasal trigeminal dysfunction. The results serve as a basis for consultation regarding outcome prediction and patient education.
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Affiliation(s)
- Dino Podlesek
- Department of Neurosurgery, TU Dresden, Dresden, Germany
| | - Yun-Ting Chao
- Smell and Taste Clinic, Department of Otorhinolaryngology, TU Dresden, Dresden, Germany.,Division of Rhinology, Department of Otorhinolaryngology-Head and Neck Surgery, Taipei Veterans General Hospital, Taipei, Taiwan.,Institute of Brain Science, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Frederike Weitkamp
- Smell and Taste Clinic, Department of Otorhinolaryngology, TU Dresden, Dresden, Germany
| | | | - Thomas Hummel
- Smell and Taste Clinic, Department of Otorhinolaryngology, TU Dresden, Dresden, Germany
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Li Y, Peng H, Zhang S, Long W, Pan Y, Li Y, Wu C, Xiao K, Wang X, Su J, Qin C, Liu Q. Preservation of the integrity of facial nerve in vestibular schwannoma microsurgery: A consecutive study of 127 clinical cases focusing on nervus intermedius. Front Oncol 2023; 13:939983. [PMID: 36845752 PMCID: PMC9947554 DOI: 10.3389/fonc.2023.939983] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Accepted: 01/23/2023] [Indexed: 02/11/2023] Open
Abstract
Background Nervus intermedius (NI) injuries are not given enough attention by neurosurgeons during vestibular schwannoma (VS) surgery. Preservation of NI function is essential for the integrity and continuity of the facial nerve, although this can be challenging. We identified the risk factors for NI injury and proposed our experience for optimizing NI preservation based on our cases. Methods We retrospectively analyzed clinical data from a consecutive series of 127 patients with VS who underwent microsurgery via the retrosigmoid approach from 2017 to 2021 at our institution. The baseline characteristics of the patients were collected from the medical records, and the incidence of NI dysfunction symptoms was obtained by outpatient and online video follow-up 6 months after surgery. The surgical procedures and techniques used were described in detail. The data were analyzed in relation to sex, age, tumor location (left or right), Koos grading scale, internal acoustic canal (IAC) invasion (TFIAC Classification), brainstem adhesion, tumor characteristics (cystic or solid), tumor necrosis, and preoperative House-Brackmann (HB) grading by univariate and multivariate analyses. Results Gross tumor removal was achieved in 126 (99.21%) patients. Subtotal removal was performed on one patient (0.79%). Twenty-three of our cases exhibited facial nerve palsy preoperatively; 21 patients had HB grade II facial palsy, and two had HB grade III. Two months after surgery, 97 (76.38%) patients had normal function of the motor portion of the facial nerve; 25 (19.69%) patients had HB Grade II facial palsy, five had Grade III (3.94%), and zero (0%) had Grade IV. Postoperatively, 15 patients experienced newly gained dry eyes (11.81%), whereas 21 cases of lacrimal disturbances (16.54%), nine of taste disturbances (7.09%), seven of xerostomia (5.51%), five of nasal hypersecretions (3.94%), and seven of hypersalivation (5.51%) were identified in our cases. Univariate and multivariate analyses revealed that the Koos grading scale and tumor characteristics (solid or cystic) were correlated with NI injury (p <0.01). Conclusion The data in this study demonstrate that although the motor function of the facial nerve is well preserved, NI disturbance is still common after VS surgery. Maintaining the integrity and continuity of the facial nerve is key to NI function. Performing bidirectional and subperineurium dissection based on even and adequate debulking is beneficial for NI preservation in VS surgery. Higher Koos grading and cystic characteristics of VS are associated with postoperative NI injuries. These two parameters can be used to guide the delineation of surgical strategy and predict the prognosis of NI function preservation.
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Affiliation(s)
- Yue Li
- Department of Neurosurgery in Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Hao Peng
- Department of Neurosurgery, Hainan General Hospital, Haikou, Hainan, China
| | - Sen Zhang
- Department of Neurosurgery in Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Wenyong Long
- Department of Neurosurgery in Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Yimin Pan
- Department of Neurosurgery in Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Yang Li
- Department of Neurosurgery in Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Changwu Wu
- Department of Neurosurgery in Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Kai Xiao
- Department of Neurosurgery in Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Xiangyu Wang
- Department of Neurosurgery in Xiangya Hospital, Central South University, Changsha, Hunan, China
| | - Jun Su
- Department of Neurosurgery, Hunan Children’s Hospital, Changsha, Hunan, China
| | - Chaoying Qin
- Department of Neurosurgery in Xiangya Hospital, Central South University, Changsha, Hunan, China,*Correspondence: Qing Liu, ; Chaoying Qin,
| | - Qing Liu
- Department of Neurosurgery in Xiangya Hospital, Central South University, Changsha, Hunan, China,Institute of Skull Base Surgery & Neuro-oncology at Hunan Neurosurgery Institute of Central South University, Changsha, Hunan, China,*Correspondence: Qing Liu, ; Chaoying Qin,
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Hostettler IC, Jayashankar N, Bikis C, Wanderer S, Nevzati E, Karuppiah R, Waran V, Kalbermatten D, Mariani L, Marbacher S, Guzman R, Madduri S, Roethlisberger M. Clinical Studies and Pre-clinical Animal Models on Facial Nerve Preservation, Reconstruction, and Regeneration Following Cerebellopontine Angle Tumor Surgery-A Systematic Review and Future Perspectives. Front Bioeng Biotechnol 2021; 9:659413. [PMID: 34239858 PMCID: PMC8259738 DOI: 10.3389/fbioe.2021.659413] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Accepted: 04/28/2021] [Indexed: 11/13/2022] Open
Abstract
Background and purpose: Tumorous lesions developing in the cerebellopontine angle (CPA) get into close contact with the 1st (cisternal) and 2nd (meatal) intra-arachnoidal portion of the facial nerve (FN). When surgical damage occurs, commonly known reconstruction strategies are often associated with poor functional recovery. This article aims to provide a systematic overview for translational research by establishing the current evidence on available clinical studies and experimental models reporting on intracranial FN injury. Methods: A systematic literature search of several databases (PubMed, EMBASE, Medline) was performed prior to July 2020. Suitable articles were selected based on predefined eligibility criteria following the Preferred Reporting Items for Systematic Reviews and Meta Analyses (PRISMA) guidelines. Included clinical studies were reviewed and categorized according to the pathology and surgical resection strategy, and experimental studies according to the animal. For anatomical study purposes, perfusion-fixed adult New Zealand white rabbits were used for radiological high-resolution imaging and anatomical dissection of the CPA and periotic skull base. Results: One hundred forty four out of 166 included publications were clinical studies reporting on FN outcomes after CPA-tumor surgery in 19,136 patients. During CPA-tumor surgery, the specific vulnerability of the intracranial FN to stretching and compression more likely leads to neurapraxia or axonotmesis than neurotmesis. Severe FN palsy was reported in 7 to 15 % after vestibular schwannoma surgery, and 6% following the resection of CPA-meningioma. Twenty-two papers reported on experimental studies, out of which only 6 specifically used intracranial FN injury in a rodent (n = 4) or non-rodent model (n = 2). Rats and rabbits offer a feasible model for manipulation of the FN in the CPA, the latter was further confirmed in our study covering the radiological and anatomical analysis of perfusion fixed periotic bones. Conclusion: The particular anatomical and physiological features of the intracranial FN warrant a distinguishment of experimental models for intracranial FN injuries. New Zealand White rabbits might be a very cost-effective and valuable option to test new experimental approaches for intracranial FN regeneration. Flexible and bioactive biomaterials, commonly used in skull base surgery, endowed with trophic and topographical functions, should address the specific needs of intracranial FN injuries.
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Affiliation(s)
- Isabel C Hostettler
- Department of Neurosurgery, Klinikum Rechts der Isar, Technical University Munich, Munich, Germany
| | - Narayan Jayashankar
- Department of Oto-Rhino-Laryngology, Nanavati Super Speciality Hospital, Mumbai, India
| | - Christos Bikis
- Department of Biomedical Engineering, Biomaterials Science Center, University of Basel, Allschwil, Switzerland.,Integrierte Psychiatrie Winterthur - Zürcher Unterland, Winterthur, Switzerland
| | - Stefan Wanderer
- Department of Neurosurgery, Kantonsspital Aarau, Aarau, Switzerland
| | - Edin Nevzati
- Department of Neurosurgery, Kantonsspital Luzern, Lucerne, Switzerland
| | - Ravindran Karuppiah
- Department of Neurosurgery, University Malaya Specialist Centre, University of Malaya, Kuala Lumpur, Malaysia
| | - Vicknes Waran
- Department of Neurosurgery, University Malaya Specialist Centre, University of Malaya, Kuala Lumpur, Malaysia
| | - Daniel Kalbermatten
- Department of Plastic Surgery, University Hospital Geneva, Geneva, Switzerland.,Department of Surgery, Biomaterials and Neuro Tissue Bioengineering, University of Geneva, Geneva, Switzerland
| | - Luigi Mariani
- Department of Neurosurgery, University Hospital of Basel, University of Basel, Basel, Switzerland
| | - Serge Marbacher
- Department of Neurosurgery, Kantonsspital Aarau, Aarau, Switzerland
| | - Raphael Guzman
- Department of Neurosurgery, University Hospital of Basel, University of Basel, Basel, Switzerland.,Department of Biomedicine, Brain Ischemia and Regeneration, University of Basel, Basel, Switzerland.,Department of Biomedical Engineering, Center for Bioengineering and Regenerative Medicine, University of Basel, Basel, Switzerland
| | - Srinivas Madduri
- Department of Surgery, Biomaterials and Neuro Tissue Bioengineering, University of Geneva, Geneva, Switzerland.,Department of Biomedicine, Brain Ischemia and Regeneration, University of Basel, Basel, Switzerland.,Department of Biomedical Engineering, Center for Bioengineering and Regenerative Medicine, University of Basel, Basel, Switzerland
| | - Michel Roethlisberger
- Department of Neurosurgery, University Malaya Specialist Centre, University of Malaya, Kuala Lumpur, Malaysia.,Department of Neurosurgery, University Hospital of Basel, University of Basel, Basel, Switzerland.,Department of Biomedical Engineering, Center for Bioengineering and Regenerative Medicine, University of Basel, Basel, Switzerland
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Matsumoto S, Osawa K, Hirose Y, Nakayama M, Wada T, Matsuda M, Akutsu H, Ii R, Koizumi H, Okano Y, Tabuchi K. Objective evaluation of gustatory function after surgery for vestibular schwannoma: A pilot study. Auris Nasus Larynx 2021; 49:183-187. [PMID: 34148726 DOI: 10.1016/j.anl.2021.05.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Revised: 04/17/2021] [Accepted: 06/03/2021] [Indexed: 11/26/2022]
Abstract
OBJECTIVE To evaluate the gustatory function before and after vestibular schwannoma (VS) surgery. METHODS In this retrospective study, we evaluated the gustatory function of 12 patients who underwent VS surgery at Tsukuba University Hospital between 2012 and 2018. Gustatory function was examined using electrogustometry before VS surgery and 3 months, 6 months and 1 year after surgery. Electrogustometry was tested at the area mapped to the chorda tympani nerve, glossopharyngeal nerve and greater superficial petrosal nerve (GSPN). Intergroup mean comparisons of the threshold were performed using a one-way analysis of variance (ANOVA) followed by the Bonferroni post-hoc test. RESULTS The gustatory function mapped to the chorda tympani nerve was significantly disturbed 6 months after the surgery as compared with the preoperative function (p = 0.033) and that the dysfunction recovered at 1 year. However, gustatory function mapped to the glossopharyngeal nerve and greater superficial petrosal nerve (GSPN) was not impaired. CONCLUSION The gustatory function mapped to the chorda tympani nerve is impaired after surgery for VS. The dysfunction peaked at 6 months after surgery, and recovered within 1 year.
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Affiliation(s)
- Shin Matsumoto
- Department of Otolaryngology, Head and Neck Surgery, Faculty of Medicine, University of Tsukuba, Tsukuba, Japan
| | - Kotaro Osawa
- Department of Otolaryngology, Head and Neck Surgery, Faculty of Medicine, University of Tsukuba, Tsukuba, Japan
| | - Yuki Hirose
- Department of Otolaryngology, Head and Neck Surgery, Faculty of Medicine, University of Tsukuba, Tsukuba, Japan
| | - Masahiro Nakayama
- Department of Otolaryngology, Head and Neck Surgery, Faculty of Medicine, University of Tsukuba, Tsukuba, Japan
| | - Tetsuro Wada
- Department of Otolaryngology, Head and Neck Surgery, Faculty of Medicine, University of Tsukuba, Tsukuba, Japan
| | - Masahide Matsuda
- Department of Neurosurgery, Faculty of Medicine, University of Tsukuba, Tsukuba, Japan
| | - Hiroyoshi Akutsu
- Department of Neurosurgery, Faculty of Medicine, University of Tsukuba, Tsukuba, Japan
| | - Rieko Ii
- Department of Otolaryngology, Head and Neck Surgery, Faculty of Medicine, University of Tsukuba, Tsukuba, Japan
| | - Hitoshi Koizumi
- Department of Otolaryngology, Head and Neck Surgery, Faculty of Medicine, University of Tsukuba, Tsukuba, Japan
| | - Yasuhito Okano
- Department of Otolaryngology, Head and Neck Surgery, Faculty of Medicine, University of Tsukuba, Tsukuba, Japan
| | - Keiji Tabuchi
- Department of Otolaryngology, Head and Neck Surgery, Faculty of Medicine, University of Tsukuba, Tsukuba, Japan.
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Metwali H, Kniese K, Kardavani B, Gerganov V, Samii M. Nervus intermedius dysfunctions after vestibular schwannoma surgery: a prospective clinical study. J Neurosurg 2019; 131:555-560. [PMID: 30192193 DOI: 10.3171/2018.4.jns1818] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2018] [Accepted: 04/02/2018] [Indexed: 11/06/2022]
Abstract
OBJECTIVE The purpose of this prospective study was to evaluate the dysfunction of the nervus intermedius (NI) after vestibular schwannoma (VS) surgery. The authors present a clinically feasible method for this purpose. METHODS In this prospective study, the authors included 30 patients who underwent surgery at the International Neuroscience Institute between May 2014 and February 2017 for resection of VS. The patients' taste sensation was examined using taste strips. Lacrimation was tested using the Schirmer I test. The clinical evaluation was performed before surgery and repeated at 2 weeks and at 6 months after surgery as well as during the follow-up, which extended up to 2 years. The authors tested the correlation between the NI dysfunctions and the House-Brackmann grade of facial nerve palsy. RESULTS The taste sensation was lost on the side of surgery in 2 patients (6.6%) and decreased in 4 patients (13.3%). The disturbance of taste sensation was not statistically correlated with dysfunctions of the motor portion of the facial nerve. The taste impairment resolved in 4 patients within 6 months, but 2 patients suffered from persistent loss of the taste sensation on the side of surgery during the follow-up. In 23 patients (76.6%), the baseline lacrimation was lower on the side of surgery, and it was significantly correlated with outcome for dysfunctions of the motor portion of the facial nerve. During the follow-up, baseline lacrimation improved in correlation with the improvement in the dysfunctions of the motor portion of the facial nerve. None of the patients reported change in salivation or nasal secretion. CONCLUSIONS The NI can be affected after VS surgery. The disturbance of baseline lacrimal secretion was correlated with dysfunctions of the motor portion of the facial nerve. However, the disturbance of the taste sensation was not correlated with the grade of facial nerve palsy. Dysfunctions of the NI should be evaluated and separately reported while analyzing facial nerve outcome after VS surgery.
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Vestibular Schwannoma Presenting as Oral Dysgeusia: An Easily Missed Diagnosis. Case Rep Dent 2016; 2016:7081919. [PMID: 27022490 PMCID: PMC4775791 DOI: 10.1155/2016/7081919] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2015] [Revised: 01/04/2016] [Accepted: 01/27/2016] [Indexed: 11/27/2022] Open
Abstract
We present a case of a fifty-year-old male patient who was referred to the Oral Medicine Department with a complaint of a salty taste. History taking subsequently revealed that the patient was also experiencing intermittent numbness of his left lower lip, tinnitus, and a feeling of fullness in the left ear. Magnetic resonance imaging was performed which revealed a large vestibular schwannoma affecting the left vestibulocochlear nerve, which was treated surgically. This case shows the importance of taking a detailed history in a patient presenting with an initial complaint of oral dysgeusia. It also highlights the possibility of significant underlying pathology, presenting with initial low level, nonspecific complaints such as an altered taste, and the rationale for imaging patients who report unilateral facial hypoesthesia.
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Neural connections between the nervus intermedius and the facial and vestibulocochlear nerves in the cerebellopontine angle: an anatomic study. Surg Radiol Anat 2015; 38:619-23. [PMID: 26470871 DOI: 10.1007/s00276-015-1571-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2015] [Accepted: 10/08/2015] [Indexed: 10/22/2022]
Abstract
PURPOSE Unexpected clinical outcomes following transection of single nerves of the internal acoustic meatus have been reported. Therefore, this study aimed to investigate interneural connections between the nervus intermedius and the adjacent nerves in the cerebellopontine angle. METHODS On 100 cadaveric sides, dissections were made of the facial/vestibulocochlear complex in the cerebellopontine angle with special attention to the nervus intermedius and potential connections between this nerve and the adjacent facial or vestibulocochlear nerves. RESULTS A nervus intermedius was identified on all but ten sides. Histologically confirmed neural connections were found between the nervus intermedius and either the facial or vestibulocochlear nerves on 34 % of sides. The mean diameter of these small interconnecting nerves was 0.1 mm. The fiber orientation of these nerves was usually oblique (anteromedial or posterolateral) in nature, but 13 connections traveled anteroposteriorly. Connecting fibers were single on 81 % of sides, doubled on 16 %, and tripled on 3 %, six sides had connections both with the facial nerve anteriorly and the vestibular nerves posteriorly. On 6.5 % of sides, a connection was between the nervus intermedius and cochlear nerve. For vestibular nerve connections with the nervus intermedius, 76 % were with the superior vestibular nerve and 24 % with the inferior vestibular nerve. CONCLUSIONS Knowledge of the possible neural interconnections found between the nervus intermedius and surrounding nerves may prove useful to surgeons who operate in these regions so that inadvertent traction or transection is avoided. Additionally, unanticipated clinical presentations and exams following surgery may be due to such neural interconnections.
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Park SH, Lee KY, Hwang SK. Nervus intermedius dysfunction following Gamma Knife surgery for vestibular schwannoma. J Neurosurg 2013; 118:566-70. [DOI: 10.3171/2012.10.jns12747] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Object
The purpose of this study was to evaluate the function of the nervus intermedius, the nonmotor component of the facial nerve, following modern Gamma Knife surgery (GKS) for the treatment of vestibular schwannoma.
Methods
Sixty-five consecutive patients at our center underwent GKS as a primary treatment option for vestibular schwannoma between 2005 and 2010. The authors interviewed patients with a functional questionnaire to evaluate the function of the nervus intermedius before and after radiosurgery from their subjective point of view. Data from 50 patients treated using GKS for a unilateral vestibular schwannoma were obtained.
Results
Nine (18%) of 50 patients presented with at least one preradiosurgical disturbance of the nervus intermedius caused by the vestibular schwannoma itself, with dysfunctions of lacrimation, salivation, nasal secretion, and taste. Of the 41 patients without preradiosurgical disturbances, 9 (22%) experienced the onset of at least one new disturbance after GKS. Specifically for each dysfunction, of the 45 patients without a lacrimal disturbance before GKS, 5 (11.1%) had a new lacrimal disturbance after GKS. New onset of a salivary disturbance after GKS was reported in 3 (6.2%) of 48 patients. In 1 patient (2%), increased nasal secretion was noted 1 year after GKS. Five (10.6%) of 47 patients without a preradiosurgical taste disturbance experienced the symptom after GKS. No facial palsy developed in any patient before or after GKS. There was no significant correlation between postradiosurgical nervus intermedius dysfunction and tumor size, margin dose, or patient age.
Conclusions
The authors demonstrated that 22% of patients undergoing modern GKS for vestibular schwannoma experience various disturbances of nonmotor components of the facial nerve as a result of the radiosurgery. Through this study, we can provide useful information about the likelihood of certain postradiosurgical symptoms for vestibular schwannoma.
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Affiliation(s)
| | - Kyu-Yup Lee
- 2Otorhinolaryngology, Kyungpook National University Hospital, Daegu, Korea
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Sasaki T, Shono T, Hashiguchi K, Yoshida F, Suzuki SO. Histological considerations of the cleavage plane for preservation of facial and cochlear nerve functions in vestibular schwannoma surgery. J Neurosurg 2009; 110:648-55. [PMID: 18928359 DOI: 10.3171/2008.4.17514] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Object
The authors analyzed the tumor capsule and the tumor–nerve interface in vestibular schwannomas (VSs) to define the ideal cleavage plane for maximal tumor removal with preservation of facial and cochlear nerve functions.
Methods
Surgical specimens from 21 unilateral VSs were studied using classical H & E, Masson trichrome, and immunohistochemical staining against myelin basic protein.
Results
The authors observed a continuous thin connective tissue layer enveloping the surfaces of the tumors. Some nerve fibers, which were immunopositive to myelin basic protein and considered to be remnants of vestibular nerve fibers, were also identified widely beneath the connective tissue layer. These findings indicated that the socalled “tumor capsule” in VSs is the residual vestibular nerve tissue itself, consisting of the perineurium and underlying nerve fibers. There was no structure bordering the tumor parenchyma and the vestibular nerve fibers. In specimens of tumors removed en bloc with the cochlear nerves, the authors found that the connective tissue layer, corresponding to the perineurium of the cochlear nerve, clearly bordered the nerve fibers and tumor tissue.
Conclusions
Based on these histological observations, complete tumor resection can be achieved by removal of both tumor parenchyma and tumor capsule when a clear border between the tumor capsule and facial or cochlear nerve fibers can be identified intraoperatively. Conversely, when a severe adhesion between the tumor and facial or cochlear nerve fibers is observed, dissection of the vestibular nerve–tumor interface (the subcapsular or subperineurial dissection) is recommended for preservation of the functions of these cranial nerves.
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Affiliation(s)
| | | | | | | | - Satoshi O. Suzuki
- 2Neuropathology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
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Stripf T, Braun K, Gouveris H, Stripf EA, Mann WJ, Amedee RG. Influence of different approaches to the cerebellopontine angle on the function of the intermediate nerve. J Neurosurg 2007; 107:927-31. [PMID: 17977262 DOI: 10.3171/jns-07/11/0927] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
OBJECT Surgery in the cerebellopontine angle (CPA) is a standard procedure at many centers. Outcome is focused mainly on preservation of hearing and facial function postoperatively. The nonmotor part of the facial nerve, the intermediate nerve, is nearly neglected nowadays. METHODS A retrospective study was designed, including a questionnaire that was sent to 178 patients who had undergone surgery between 2000 and 2004. Data were obtained in 156 cases. The questionnaire was divided into five parts assessing the presence of increased tearing, reduced tearing, salivation disturbances, increased nasal secretions, and abnormalities in taste. Finally, a self-assessment of patient symptoms was analyzed. RESULTS Postoperatively, 70 patients (45%) experienced crocodile tears, whereas 62 (40%) had dry eyes. Disturbances in taste were noted in six patients (4%) preoperatively and in 52 patients (33%) after surgery. Increased nasal secretion was noted in 68 patients (44%) postoperatively. An analysis of the correlation between the surgical approach used and disturbances in the intermediate nerve revealed a strong tendency to a higher rate of symptoms following the middle fossa approach (p = 0.071, chi-square test). CONCLUSIONS Data in this study demonstrate the clinical importance of nonmotor defects associated with CPA tumor removal. More than 50% of the patients in this study reported postoperative crocodile tears, dry eyes, nasal secretions, and/or taste disturbances. These sequelae may affect both short- and long-term postoperative quality of life to the same extent as deafness or transient facial paresis. The risk of injury seems to be higher after the middle fossa approach.
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Affiliation(s)
- Tobias Stripf
- Department of Ear-Nose-Throat, University of Mainz Medical School, Mainz, Germany.
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