Salvage surgery of vestibular schwannoma after failed radiotherapy: The Gruppo Otologico experience and review of the literature

Objectives

The use of radiation therapy has largely widespread and becomes in many centers the preference modality of treatment for symptomatic patients who are old, medically unfit for surgical therapy, those who refuse surgery and in some recurrent or residual growing tumors.The risk of radiotherapy failure in the treatment of vestibular schwannoma might be underestimated in the literature. The purpose of this study is to show the Gruppo Otologico experience with salvage surgery to better understand the surgical outcomes and difficulties in treating vestibular schwannoma after failed radiotherapy.

Study design

Retrospective chart review of patients who required salvage surgery of vestibular schwannoma after failed radiotherapy.

Settings

Quaternary referral otology and skull base center.

Results

Between 1987 and 2010, 2500 cases of VS underwent surgical treatment at the Gruppo Otologico. Nineteen patients had received stereotactic radiation therapy before the surgical treatment. The interval time between radiotherapy and surgical salvage ranged from 1 to 10 years.In all the cases decision of surgery was taken following an increase in tumor size with or without new onset of symptoms. Complete tumor removal was achieved in 86.6% of the cases through a transotic, transcochlear or enlarged translabyrinthine approach with trans-apical extension.Difficult dissection of the tumor was encountered in 93.3% the cases. The facial nerve was anatomically preserved in 93.3% but its function was worsened in 73.3% of patients after at least 6 months of follow up. Malignant transformation of the vestibular schwannoma was encountered in one patient.

Conclusion

Complete surgical resection of VS is more difficult after radiotherapy with relatively poor facial nerve outcomes and nearly impossible hearing preservation.Patients who receive radiation therapy for the treatment of vestibular schwannoma should be made aware of its potential complications and risk of failure, especially in young patients and NF2 cases.     

Posterior fossa meningioma: surgical strategy

Posterior fossa meningioma is the second most common tumor in the cerebellopontine angle. It has a higher rate of postoperative morbidity and mortality compared to acoustic neuroma. Forty posterior fossa meningioma patients managed in our centers were reviewed. Thirty-nine patients were managed surgically with 42 surgical procedures. The approaches used were the translabyrinthine approach in 18 patients (43%), the modified transcochlear in 11 cases (26%), the petro-occipital transsigmoid in 5 cases (12%), the suboccipital in 4 cases (10%), the petro-occipital trassigmoid transcervical in 2 cases (5%), the petro-occipital transsigmoid transtentorial in 1 case (2%), and a subtemporal transtentorial for another case (2%). Facial nerve anatomical integrity was preserved in 87% of procedures but was interrupted in 5 cases, with 4 of the latter subsequently repaired. Total tumor removal was accomplished in 38 cases. A second-stage total tumor removal is planned for the remaining case. There was only one case of perioperative death and no cases of radiological recurrence so far.     

Surgical anatomy of the extended middle cranial fossa approach

The extended middle cranial fossa approach includes removal of the petrous bone from its subtemporal surface in order to expose widely the internal auditory canal and the posterior fossa dura around its porus while preserving all the important and closely related anatomical structures. We have dissected 25 temporal bones and five fresh cadavers in order to define the limits of this approach. Measurements were obtained between the different structures to find reliable angles and distances that could guide working in this area. A new method of identification of the internal auditory canal is discussed based on the measurements taken.The results of the present work showed wide variations in the different structures. The arcuate eminence was coincident with the superior semicircular canal in only 48% of bones. Dehiscence of the geniculate ganglion and of the internal carotid artery was noted in 16% and 20% of specimens, respectively. The angles measured between the different structures showed great variations. However, the angle between the internal auditory canal and superior petrosal sinus was constant. Though the extended middle cranial fossa is a versatile approach, it affords a limited access to the cerebellopontine angle. A thorough understanding of the complex and variable anatomy of this area is necessary should this approach be utilized.     

Surgical management of vestibular schwannoma in elderly patients

This study aimed to evaluate surgical results of vestibular schwannoma in elderly patients using a retrospective study in a Quaternary Neurotology and Skull Base Referral Center setting. The data of 232 elderly patients (above 65 years) operated on for vestibular schwannoma in the period between April 1987 and July 2009 were reviewed. Most patients were operated on via translabyrinthine approach (TLA) using transapical extension for large tumors. Other approaches used were retrosigmoid, middle cranial fossa, and transcochlear. Total tumor removal was achieved in the majority of cases, while planned subtotal removal was used in specific occasions. Postoperative complications included facial nerve palsy, other cranial nerves injury, persistent instability, intracranial hemorrhage, CSF leak, meningitis, and death. Patients were followed after surgery for tumor regrowth or occurrence of complications. The results showed low rate of morbidity and mortality. Despite that complete removal is the main target of the surgery; adoption of subtotal removal in selected cases can improve postoperative facial nerve results and reduce the duration of surgery.     

Inner ear cholesteatoma and the preservation of cochlear function

Labyrinthine destruction by direct cholesteatoma invasion has always been considered a serious threat to the inner ear function. A number of reports in the literature have cited both patients who had preservation of hearing despite widespread erosion of the labyrinth by cholesteatoma and patients who had retained auditory function despite surgical removal of the matrix from the labyrinth. In most cases the vestibular portion of the inner ear was invaded but cases of cochlear involvement have been described as well. Twelve cases with pre-operative auditory function preservation despite extensive labyrinthine destruction treated at our Institution are reported. Seven cases retained cochlear function post-operatively. Possible explanations of this occurrence and implications of related with hearing preservation in the presence of widespread inner ear destruction by chronic inflammatory disease are discussed.     

Obstructive endotracheal lesions of thyroid cancer

Airway invasion is a life-threatening complication of thyroid cancer. An important issue that deserves better attention is the differentiation between the clinical features of tracheal wall invasion versus those of an obstructive endotracheal lesion. We present information on the clinical course, diagnostic modalities utilized, management instituted, along with the prognosis, and follow-up data on a group of patients presenting with obstructive endotracheal lesions of thyroid cancer. Two thousand four hundred and eighty-nine thyroid cancer patients were seen at our institution from December 1975 to May 2000. Thirteen patients presented with symptoms of respiratory distress related to obstructive endotracheal lesions. At presentation, 11 patients underwent endoscopic examination. Imaging studies consisting of I123 whole body scan (WBS), computed tomography/magnetic resonance imaging (CT/MRI) of neck and chest, whole body positron emission tomography using 18-fluoro-2-deoxy-D-glucose ((FDG)PET) were done, as also was determination of the tumour markers, serum thyroglobulin (TG) and calcitonin. Patients were followed for one to 108 months after the initial presentation. Intraluminal tracheal obstruction was severe in eight patients; five had near-total-occlusion. Paralysis of the vocal folds was present in five. Evidence of metastatic disease was present in most patients. Dissociation between iodine uptake and TG synthesis was evident in five patients during follow-up. Four patients died of cancer. Of the nine living patients; cancer persisted in six, recurred in two patients, and remitted in one. This study has identified obstructive endotracheal lesion of thyroid cancer as a distinct entity apart from tracheal wall disease. These data provide evidence that intraluminal tracheal invasion of thyroid cancer is an ominous sign and a frequent cause of morbidity.     

Enlarged translabyrinthine approach for the management of large and giant acoustic neuromas: a report of 175 consecutive cases

The translabyrinthine approach was once considered inadequate for the removal of acoustic neuromas (ANs), but that theory has few proponents today. Over the years, the translabyrinthine approach has been modified into the enlarged translabyrinthine approach, with experience and technical refinements leading to a wider access. Between April 1987 and December 2001, the Gruppo Otologico of Piacenza-Rome was able to remove 175 ANs 3 cm or larger in size from the cerebellopontine angle by adopting this modified surgical technique. These tumors represented 24.7% of all 707 ANs for which surgery was performed during the same period of time. Among the 175 cases, there was only 1 death. The incidence of complications was very low and was comparable to results previously published in the literature. Consequently, the hospital stay was short, with a mean of 7.3 days (5.1 days in the last 45 cases). The preoperative ipsilateral hearing was already compromised in 119 of the 175 cases (68%; class C/D according to the Committee on Hearing and Equilibrium of the American Academy of Otolaryngology-Head and Neck Surgery, 1995). From our results, we can conclude that the use of the enlarged translabyrinthine approach in AN surgery is not dependent on tumor size. On the contrary, the advantages of a low rate of morbidity and a short hospital stay are ample proof that this is the best approach for the removal of large ANs.     

Transapical extension in difficult cerebellopontine angle tumours: preliminary report

Difficult cerebellopontine angle (CPA) tumours namely large/giant vestibular schwannomas, vestibular schwannomas with a significant anterior extension and meningiomas of the posterior surface of the petrous bone extending anterior to the internal auditory canal (IAC) have always posed a problem for the otoneurosurgeon. Modifications of the enlarged translabyrinthine approach (ETLA) specifically aimed at dealing with these tumours are not reported. The aim of this paper is to introduce the transapical extension of ETLA which involves increased circumferential drilling around the IAC beyond 270 degrees C. The extension allows enhanced surgical control over the tumour as well as the anterior aspect of the CPA including the prepontine cistern, the Vth and VIth cranial nerves. The extension is further classified into Type I and II depending upon the extent of drilling. Type I extension entails drilling around the IAC for 300-320 degrees and is indicated for large/giant vestibular schwannomas (large vestibular schwannoma extrameatal diameter 3-39 cm, giant vestibular schwannoma extrameatal diameter >or=4 cm) and vestibular schwannomas with significant anterior extension. Type II extension involves complete drilling around the canal for 360 degrees and is indicated for meningiomas of the posterior surface of the petrous bone extending anterior to the IAC.