Introduction Vestibular schwannoma (VS) is a benign tumor originating from the eighth cranial nerve, which leads to progressive ipsilateral hearing loss over its natural course. Currently, preserving natural hearing has become one of the primary objectives in the treatment of small VS. While in the past, conservative treatments (observation and radiotherapy) were preferred for small tumors, hearing preservation surgery (HPS) has now emerged as a valid therapeutic alternative due to its low morbidity. However, despite very good postoperative auditory outcomes, a percentage of patients experience surgical failure in hearing preservation. Therefore, analyzing the clinical-pathological prognostic factors associated with good postoperative hearing outcomes has become essential for improving patient selection and optimizing the functional outcomes of this type of surgery. Objective The primary objective of this prospective study was to evaluate the correlation between postoperative auditory outcomes and the vestibular branch of origin of VS in patients undergoing HPS via a retrosigmoid approach. The secondary objective was to analyze the ability of certain preoperative vestibular function tests to predict the tumor's branch of origin, aiming to improve the preoperative selection of patients suitable for HPS in the future. Materials and Methods Between 2012 and 2024, 290 patients underwent surgical removal of vestibular schwannoma (VIII cranial nerve). Among these, 67 patients underwent tumor excision via Hearing Preservation Surgery (HPS). From this latter group, the study included the 8 patients who, in the last year and a half, underwent comprehensive audiological and vestibular evaluations (including pure-tone and speech audiometry, matrix test, Video Head Impulse Test, vestibular evoked myogenic potentials, posturography, Dizziness Handicap Inventory questionnaire, and videonystagmography) followed by retrosigmoid surgical excision of the vestibular schwannoma with the intent of preserving natural hearing, according to the technique of hearing preservation surgery. Postoperatively, auditory outcomes were assessed using pure-tone and speech audiometry and were correlated with the intraoperatively identified vestibular nerve branch (superior or inferior) from which the tumor originated. The concordance between the preoperative vestibular evaluation and the intraoperative findings was also explored. Results Overall, at the 3-month follow-up, 2 patients (25%) did not retain hearing. The remaining 6 patients preserved hearing with mean values of PTA4, SDT, RDS, and SDS at 24.1 dB, 22.5 dB, 31.66 dB, and 100%, respectively. The 2 patients who did not preserve hearing had the worst preoperative audiological results (ABR and matrix test). During surgery, the inferior vestibular nerve (IVN) was identified as the tumor's origin site in 4 patients; in all these patients, natural hearing was preserved. In the 2 tumors originating from the superior vestibular nerve (SVN) (25%), natural hearing was preserved in 1 patient. In the remaining 2 patients (25%), it was not possible to intraoperatively identify the tumor's branch of origin. In those patients where preoperative and intraoperative identification of the nerve of origin was possible, the concordance between the preoperative vestibular evaluation and the intraoperative findings was 80%. Conclusions Contrary to what is reported in the literature, our study shows that tumors originating from the inferior vestibular nerve can have a good postoperative auditory outcome, especially if preoperative hearing function is well preserved. Our data, therefore, support early surgery for small tumors with good preoperative hearing, regardless of the supposed branch of origin. Furthermore, preoperative vestibular evaluation can be a useful tool to predict the tumor's branch of origin, although further studies are necessary to establish standardized study protocols.
Introduzione Lo schwannoma vestibolare è un tumore benigno originante dall’VIII nervo cranico che determina nel corso della sua storia naturale una perdita progressiva dell’udito omolaterale. Ad oggi, la preservazione dell’udito è diventata uno degli obiettivi principali del trattamento dello SV di piccole dimensioni. Se in passato per i tumori piccoli i trattamenti considerati conservativi (osservazione e radioterapia) venivano preferiti, attualmente la hearing preservation surgery è diventata una valida alternativa terapeutica per la sua bassa morbidità; tuttavia, sebbene i risultati uditivi postoperatori siano buoni, in una percentuale di pazienti l’intervento chirurgico fallisce nella preservazione dell’udito. L'analisi dei fattori prognostici clinico-patologici correlati all'outcome uditivo postoperatorio è diventata quindi essenziale per migliorare la selezione dei pazienti e ottimizzare gli esiti funzionali di questo tipo di chirurgia. Scopo dello studio L'obiettivo principale di questo studio prospettico è stato valutare la correlazione tra gli outcome uditivi postoperatori e la branca vestibolare di origine dello SV nei pazienti sottoposti a HPS tramite approccio retrosigmoideo (RS). L'obiettivo secondario è stato analizzare la capacità di alcuni test di funzionalità vestibolare eseguiti preoperatoriamente di predire la branca di origine del tumore, al fine di migliorare la selezione preoperatoria dei pazienti a cui proporre una HPS. Materiali e metodi Tra il 2012 e il 2024 sono stati operati di asportazione di neurinoma dell’VIII nc 290 pazienti. Di questi sono stati sottoposti ad exeresi del tumore tramite HPS 67 pazienti. Tra quest’ultimo gruppo di pazienti, sono stati inclusi nello studio gli 8 pazienti che nell’ultimo anno e mezzo sono stati sottoposti a valutazione audiologica e vestibolare complete (comprendenti esame audiometrico tonale e vocale, matrix test, Video Head Impulse Test, potenziali evocati miogenici vestibolari, posturografia, questionario DHI e videonistagmografia) e successiva exeresi di SV per via RS con intento di preservare l’udito naturale. Postoperatoriamente sono stati valutati i risultati uditivi tramite esame audiometrico tonale e vocale e questi sono stati messi in correlazione con la branca vestibolare di origine del tumore identificata intraoperatoriamente. E’ stata esplorata anche la concordanza della valutazione vestibolare preoperatoria con il dato riscontrato intraoperatoriamente. Risultati Globalmente, a 3 mesi di follow-up 2 pazienti (25%) non hanno conservato l’udito. I restanti 6 pazienti hanno conservato l’udito con valori medi di PTA4, SDT, RDS e SDS risultati rispettivamente 24.1 dB, 22.5 dB, 31.66 dB e 100%. I 2 pazienti che non hanno preservato l’udito sono risultati essere quelli con risultati peggiori agli approfondimenti audiologici (ABR e matrix test) preoperatori. Durante l'intervento, il nervo vestibolare inferiore è stato identificato come sito di origine del tumore in 4 pazienti; in tutti questi pazienti è stato preservato l’udito naturale. Nei 2 tumori ad origine dal nervo vestibolare superiore (25%), l’udito naturale è stato preservato in 1 paziente. Nei restanti 2 pazienti (25%) non è stato possibile identificare intra-operatoriamente la branca di origine del tumore. In quei pazienti in cui è stata possibile l’identificazione preoperatoria del nervo di origine, la concordanza tra valutazione vestibolare preoperatoria e riscontro intraperatorio è stata dell’80%. Conclusioni Contrariamente a quanto riportato in letteratura, dal nostro studio emerge come i tumori originanti dall'IVN possano avere un buon outcome uditivo postoperatorio, soprattutto se la funzione uditiva preoperatoria è ben conservata. Inoltre, la valutazione vestibolare preoperatoria può essere un utile strumento per prevedere la branca di origine, sebbene siano necessari ulteriori studi per la creazione di protocolli standardizzati.
L'influenza del nervo di origine nella chirurgia dello Schwannoma vestibolare sulla funzione uditiva.
QUAGLIA, SOFIA
2023/2024
Abstract
Introduction Vestibular schwannoma (VS) is a benign tumor originating from the eighth cranial nerve, which leads to progressive ipsilateral hearing loss over its natural course. Currently, preserving natural hearing has become one of the primary objectives in the treatment of small VS. While in the past, conservative treatments (observation and radiotherapy) were preferred for small tumors, hearing preservation surgery (HPS) has now emerged as a valid therapeutic alternative due to its low morbidity. However, despite very good postoperative auditory outcomes, a percentage of patients experience surgical failure in hearing preservation. Therefore, analyzing the clinical-pathological prognostic factors associated with good postoperative hearing outcomes has become essential for improving patient selection and optimizing the functional outcomes of this type of surgery. Objective The primary objective of this prospective study was to evaluate the correlation between postoperative auditory outcomes and the vestibular branch of origin of VS in patients undergoing HPS via a retrosigmoid approach. The secondary objective was to analyze the ability of certain preoperative vestibular function tests to predict the tumor's branch of origin, aiming to improve the preoperative selection of patients suitable for HPS in the future. Materials and Methods Between 2012 and 2024, 290 patients underwent surgical removal of vestibular schwannoma (VIII cranial nerve). Among these, 67 patients underwent tumor excision via Hearing Preservation Surgery (HPS). From this latter group, the study included the 8 patients who, in the last year and a half, underwent comprehensive audiological and vestibular evaluations (including pure-tone and speech audiometry, matrix test, Video Head Impulse Test, vestibular evoked myogenic potentials, posturography, Dizziness Handicap Inventory questionnaire, and videonystagmography) followed by retrosigmoid surgical excision of the vestibular schwannoma with the intent of preserving natural hearing, according to the technique of hearing preservation surgery. Postoperatively, auditory outcomes were assessed using pure-tone and speech audiometry and were correlated with the intraoperatively identified vestibular nerve branch (superior or inferior) from which the tumor originated. The concordance between the preoperative vestibular evaluation and the intraoperative findings was also explored. Results Overall, at the 3-month follow-up, 2 patients (25%) did not retain hearing. The remaining 6 patients preserved hearing with mean values of PTA4, SDT, RDS, and SDS at 24.1 dB, 22.5 dB, 31.66 dB, and 100%, respectively. The 2 patients who did not preserve hearing had the worst preoperative audiological results (ABR and matrix test). During surgery, the inferior vestibular nerve (IVN) was identified as the tumor's origin site in 4 patients; in all these patients, natural hearing was preserved. In the 2 tumors originating from the superior vestibular nerve (SVN) (25%), natural hearing was preserved in 1 patient. In the remaining 2 patients (25%), it was not possible to intraoperatively identify the tumor's branch of origin. In those patients where preoperative and intraoperative identification of the nerve of origin was possible, the concordance between the preoperative vestibular evaluation and the intraoperative findings was 80%. Conclusions Contrary to what is reported in the literature, our study shows that tumors originating from the inferior vestibular nerve can have a good postoperative auditory outcome, especially if preoperative hearing function is well preserved. Our data, therefore, support early surgery for small tumors with good preoperative hearing, regardless of the supposed branch of origin. Furthermore, preoperative vestibular evaluation can be a useful tool to predict the tumor's branch of origin, although further studies are necessary to establish standardized study protocols.| File | Dimensione | Formato | |
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https://hdl.handle.net/20.500.12608/67053