RESUMO
Background: The management of vestibular schwannoma has evolved over the past hundred years. In the last decades, surgery has been gradually replaced by radiation therapy as a primary treatment modality, particularly for small tumors, due to the less invasive nature and the compared reported outcomes in tumor control and hearing preservation. However, irradiation sometimes fails to stop tumor growth. In a long-term follow-up after primary fractionated stereotactic radiotherapy, the rate of treatment failure was reported as 3% and needed surgical salvage. For single-fraction modality, Hasegawa et al. reported salvage treatment after primary Gamma Knife radiosurgery in 8%, where 90% of these underwent surgery and 50% of those who were treated with a second gamma knife surgery required surgical intervention later. An increase in tumor volume by more than 10-20%, tumor growth after three years, and no return to pretreatment volume after transient swelling have been considered as tumor recurrence rather than pseudoprogression, a transient increase in tumor volume after radiotherapy that occurs up to 30% of cases. It has been reported that microsurgery after radiotherapy is more difficult, with most authors reporting a loss of defined arachnoid planes and worse cranial nerve outcomes, especially for hearing and facial nerve function. Case Description: A 43-year-old female patient was incidentally (asymptomatic) diagnosed on a magnetic resonance imaging (MRI) scan harboring a left vestibular schwannoma, grade T2 (Hannover classification), in 2015. Neurologic examination was unremarkable, and audiometry testing was normal. She was initially treated with observation. Three years later, in 2018, the lesion had enlarged, becoming a grade T3a and reaching the cistern of the cerebellopontine angle. The tumor was then treated with fractionated stereotactic radiosurgery (5 sessions of 5 Gy). MRI scans in 2019 and 2020 showed slight tumor growth. This enlargement was attributed to a pseudoprogression after radiosurgery, and only observation was advocated. In 2022, 4 years later, after radiosurgery, the tumor was still growing, and the patient began to suffer from hearing loss. A failure treatment was considered, and microsurgery was indicated. The patient was counseled about the risk of functional nerve impairment, and surgical consent was obtained. A retro sigmoid approach was planned. A gross total resection was attempted due to the clear subperineural plane during tumor dissection and because it was the only option that would provide a cure for the patient. The adjacent neurovascular structures were firmly adhered to the tumor capsule, which represented a major challenge for microdissection. The tumor was soft, without significant bleeding. A total resection was achieved, and the facial nerve was anatomically preserved. The patient developed facial paresis (House-Brackmann III) in the immediate postoperative period, which improved at the 6-month follow-up. Hearing loss did not improve. Postoperative MRI showed total resection. Conclusion: Microsurgery after radiotherapy for vestibular schwannoma is challenging in terms of indication, when to indicate, resection target, difficulty in dissection due to local changes, and outcome. Gross total resection may be considered, as it is the only treatment that may provide a cure for the patient. However, the patient should be counseled about the risks.
RESUMO
BACKGROUND: Cavernous hemangiomas, more accurately defined as cavernous venous malformations, constitute the most common primary intraorbital tumors of adults comprising 4-9% of all tumors,[4] and the second most frequent cause of unilateral proptosis after thyroid-related orbitopathy.[3] Over 80% are located within the intraconal compartment, most commonly in the lateral aspect.[1] Surgical treatment for orbital cavernous hemangioma is generally required in symptomatic cases, optic nerve compression, and cosmetically disfiguring proptosis.[2] Transcranial approaches, the most familiar approaches for neurosurgeons, provide wide access to the entire superior and lateral orbit. They usually offer direct visualization, allowing for a safer dissection, while minimizing significant injury to the native neural and vascular anatomy of the orbit.[5] Although transcranial approaches continue to evolve, in many cases, they have been supplanted by endoscopic skull base approaches and modifications to deep lateral orbitotomy approaches.[5]. CASE DESCRIPTION: A 62-year-old male patient presented with slowly expanding left proptosis, which he had first noticed 3 years before presentation. He was already blind in his right eye due to a history of traumatic amaurosis in childhood. The left eye examination revealed severe proptosis with restricted eye movement in all directions and significant visual impairment (visual acuity of 20/300, expressed by Snellen test, with no improvement on correction). MRI of the orbit showed a large left superolateral intraconal cavernous hemangioma compressing and displacing the optic nerve, with the typical feature of slow gradual irregular enhancement with delayed washout on contrast-enhanced image. A one-piece modified orbitozygomatic approach was performed and a total en block resection was achieved. The bone flap was fixed with titanium miniplates and screws, the temporal muscle and the skin were closed in a standard fashion. The patient did not present any new deficit in the postoperative period. The patient had good functional and cosmetic outcomes with resolution of proptosis, restoration of eye movements, and improvement of visual acuity in the 3-month follow-up. Postoperative MRI showed total resection. CONCLUSION: The orbitozygomatic approach for large orbital cavernous hemangioma provides satisfactory orbital decompression and large working space, reduces traction, and increases visualization and freedom to dissect small vessels and nerves that may be tightly attached to the tumor pseudocapsule.