Skull Base Surgeries
What is skull base?
It is the bony base on which the brain rests. It is intimately related to various cranial nerves and vessels. Diseases at this site were earlier dealt with open skull methods like craniotomy with brain retraction , obvious scarring & a traumatic, prolonged post operative period. Given below are the pictures of base of skull & the nerves related.
Now, with the advent of endosopes straight & angled, these areas are easily approached through the nose, mouth or through key hole openings. Patient's cosmesis is maintained. Due to the direct approach through the sinuses many vital structures are safeguarded & preserved. The duration of surgery which used to be 6 to 10 hours earlier by open methods, has come down to 1 to 2 hours. The post operative stay is usually a day or two cutting down the cost factor, assured disease clearance & patient comfort.
The endoscope skull base surgery is a major milestone in the management of the following problems:
- Pituitary tumours with supra and para sellar extension
- Clival tumours
- CSF leaks
- Parapharyngeal tumours
- Optic Nerve Decompression in
- Traumatic optic neuropathy,
- Fibrous dysplasia involving optic canal
- Craniofacial stenosis with optic canal narrowing
- Optic nerve sheath tumours and
- Fungal Sinusitis encroaching optic canal
- Papilloedema causing visual deficit despite maximum medical treatment
- Orbital decompression in orbital tumours both benign and malignant, thyrotoxicosis with ophthalmopathy.
- Tumours of sinuses with intra cranial extension
- Cerebellopontine angle tumours
Thus the advantages of Endoscopic Skull Base Surgery are:
- Shortest direct route – right on the target
- Closer view with magnification
- Panoramic view
- Shorter operating time
- No scars – Natural passage like the nose is used.
- No morbidity – no need to open the skull
- Assured disease clearance because of better view.
- Easy documentation & teaching aid
- Comfortable post operative period
- Shorter hospital stay
- Cost effective
- Can be taken to rural areas due to its portability
Endoscopic pituitary tumour/adenoma removal:
Pituitary gland is a master gland that lies in the center of skull base having ultimate control over all the hormones secreted in our body. Small tumours may arise from this gland with the patient complaining of headache or visual disturbances or hormonal problems like weight gain, secretion of milk, coarsening of facial features, menstrual irregularities and infertility. It earlier required extensive procedures with ugly scars on the face. Now it is being approached through sphenoid sinus as in routine FESS and then on opening one of its wall, we visualize the pituitary gland direct. Any extension of the tumour to the sides or extending up also can be given full clearance. A graft is required at times to seal brain fluid leakage. This is also taken from the nose so that there is no scar elsewhere. The post operative comfort rendered to the patient is immense. Angled view rendered by endoscope has decreased the recurrence rate. This requires just one day hospitalization & hence cost effective too. The requirement to take hormonal replacements is also minimized. About 154 pituitary surgeries have been done without any mortality & with minimal minor complications. A neurosurgeon is also in the team. Preoperative evaluation by the endocrinologist, neuro ophthalmologist is done. Radiation oncologist opines as and when necessary.
Endoscopic CSF Leak Repair:
Cerebrospinal fluid is a fluid which surrounds the brain & gives a cushioning effect preventing injury to brain. When there is some breach in skull or in the layers covering the brain, this fluid leaks out. The danger being both loss of protection to brain as well as availability of a channel for infection spreading to brain. Earlier these were closed by open procedures requiring breaking open the skull vault with lot of manipulation of vital structures. The graft for patching the defect was taken from the thigh by a separate incision. The latest & more practical trend is endoscopic closure of the CSF leak which is done at our hospital. The nasal endoscope enables to clearly visualize the site of leak & the breach is closed with cartilage or mucosa which can be harvested from the nasal cavity itself. The advantages are that there is no external scar and no post operative morbidity. The patient is sent home that very day with a nasal pack. The pack is retained for 1 week by which time the breach is completely sealed off.
Endoscopic Clival tumour removal:
Clivus is a region in the skull base just below the pituitary area. Tumors of this region were earlier dealt by face splitting incision with extensive brain retraction leading to a pathetic post operative period. This procedure used to take 4-5 hours just to reach the tumor. Now with the endoscope, in no time we are able to reach the target area and that too without any facial disfigurement. Through the nostrils, opening the sphenoid sinus and working little below, we reach the clival area. Very good disease clearance is obtained. Operating with this method is safe. This procedure takes 1 to 2 hours with a single day hospitalization. Should there be a recurrence the site can be accessed through the ready passage.
Cerebello Pontine Angle Tumour:
These are tumours in the brain which require extensive & elaborate approach. They affect the hearing nerve, facial nerve & patient can loose balance. These were neuro surgeon's territory earlier. Now this is a combined approach where the neurosurgeon does the preliminary exposure of brain through a small incision. Then the endoscopic ENT surgeon removes the tumour without injuring the vital nerves enabled by better visualization.
These are very vascular tumors of the jugular bulb. Patient presents with hearing difficulty or a buzzing sound in the ear. These require radio imaging & pre operative embolisation i.e blocking of the blood vessel that feeds the tumor to shrink it's size as well as to lessen per operative bleeding. Depending on the size of the mass either an open technique or an endoscopic method is adopted.