Neurotology and Lateral Skull Base Surgery is a speciality that has developed over the last few years. Skull base lesions ( tumors at the base of the brain) which were previously excised via pure neurosurgical routes by neurosurgeons can now be removed alternatively through various transtemporal routes i.e. approaches through and around the ear. These approaches are beneficial in many cases since it avoids brain retraction or handling of the brain tissue. However, it is the co-operation between the otologist (ear surgeon) and the neurosurgeon that decides in offering a surgical route to a lesion best suited for the subject.
A few representations are given below to understand what Neurotology and Lateral Skull Base Surgery offers
Vertigo can be due to varied causes. Meniere’s disease is a condition causing vertigo that is treated medically. However, if the vertigo of Meniere’s affects the quality of life, then surgery is recommended. Surgeries include primarily endolymphatic sac decompression and selective vestibular neurectomy. Both these surgeries are performed through the area behind the ear.
Trigeminal neuralgia is a condition causing severe agonizing pain on the affected side of the face. It is occasionally caused by a vascular loop impinging on the root entry zone of the trigeminal nerve which is responsible for facial sensations. This gives paroxysms of pain that are severe on the affected side of the face. If a vascular loop is proven to be the cause of the trigeminal neuralgia, separation of the vascular loop from the root entry zone of the trigeminal nerve gives immediate and dramatic relief. In case of lesions affecting the trigeminal nerve, these lesions can also be removed through various approaches.
Hemifacial spasms are uncontrolled involuntary spasms of one side of the face which appear like facial twitches. It is sometimes caused by a vascular loop abutting the facial nerve at the root entry zone. Separation of the vascular loop from the root entry zone of the facial nerve gives immediate relief from the spasms.
Vestibular schwannoma is a tumor of the nerve of balance. It causes vertigo and even varied degrees of hearing loss. Tinnitus or ringing of the affected ear is also a symptom described by some. The treatment of vestibular schwannoma is individualized based on numerous factors. If surgery is required, we perform all the approaches, namely the translabyrinthine, retrosigmoid and middle cranial fossa approach as is indicated in the particular case.
Glomus tumors are paragangliomas that cause hearing loss, bleeding from the ear or weakness of one of the lower cranial nerves. Glomus tympanicum tumors are treated by transcanal approach whereas glomus mastoidalis are treated by a transmastoid approach. A variety of infratemporal fossa approaches are devised to treat glomus jugulare based on their extent. We embolize the glomus jugulare tumors to decrease their vascularity and aid their excision during surgery.
Facial nerve schwannomas can present with either hearing loss or sometimes with weakness of the face on the side of the lesion. If surgery is indicated, it involves excising the schwannoma and grafting the facial nerve.
It usually presents with a weakness of the affected cranial nerve which may cause swallowing, hoarseness or speech difficulty. Excision of the schwannoma has to be followed up by appropriate swallowing or speech therapy.
Meningiomas are tumors that originate from the covering of the brain and can present at various locations at the base of the brain. They represent the second most common type of tumors found in the brain. Asymptomatic meningiomas are usually left alone but symptomatic tumors are excised by neurosurgical or lateral skull base surgery approaches.
Meningoencephalocoeles are herniations of meninges with a part of the brain through defects at the base of the skull into the ear causing hearing loss, leakage of cerebrospinal fluid through the ear or nose or even epilepsy. This is cured through surgery and the defect in the skull base is repaired in layers.
The malignancies of the ear need to be diagnosed accurately and appropriate treatment instituted. Surgery is tailored according to the extent of the lesion. Appropriate reconstruction is planned preoperatively and subject counselled accordingly. Adjuvant treatment like radiotherapy or chemotherapy may be necessary additionally.
A variety of other lesions are also removed by Lateral skull Base approaches. Only the commoner lesions are mentioned above.