Operating Room Notes

Editors Note: Turns out it was only 5.5 CM, do I feel cheated.
PS - I like the "Service Date" ...

Sunnybrook & Women's College
Health Sciences Centre
Sunnybrook Campus

OPERATIVE NOTE
PT NAME: LALLEY, JOHN
SERVICE DATE: 12-JAN-2005
PREOPERATIVE DIAGNOSIS:
Right large cystic Vestibular Schwannoma (5.5 CM) with hearing loss and imbalance with facial
numbness.

POSTOPERATIVE DIAGNOSIS:
PROCEDURE:
1) Translabyrinthine infratentorial excision of tumour and microscopic dissection and facial nerve monitoring. Duraplasty, labyrinthectomy and abdominal fat graft and periosteal flap closure and temporalis fascia

SURGEON: Dr. JOSEPH CHEN
ASSISTANT: Dr. F. Pirouzmand I Dr. B. Rotenberg I Dr. A. Marshall

PROCEDURE:
This man with a large right CP angle tumour with a large cystic component and significant brainstem and cerebellar compression. He has a right sided progressive hearing loss and imbalance with mild trigeminal symptoms as well. He understands the options for treatment and has decided to undergo surgical treatment. He was apprised of the benefits of this surgery. Preoperative investigations showed no contraindication to surgery.

OPERATION: The patient was identified and brought to the O/R suite. Under general anaesthetic and under oral tracheal intubation, the patient was positioned for surgery. His head was fixed in a Mayfield head frame. The posterior scalp was shaved and the facial nerve monitoring was established as well as the trigeminal nerve and the smaller drains and the somatosensory evoked potentials.The attention was then focused on the abdomen whereby a left mid quadrant transverse incision was made, and a large morsel of fat obtained to be used at a later stage.The skin was closed in a standard fashion with a suction drain. Then following this, the head was prepped and draped and a large post auricular incision was made and the dissection was then carried out. A large Paiva periosteal flap and temporalis muscle rotational flap were prepared and later used.

Using a Bien aire drill, a large mastoidectomy and decompression of the middle cranial fossa and sigmoid sinus were completed. Following this and under the microscope. a labyrinthectomy and the translabyrinthine bony resection was then prepared. The posterior fossa dura was likewise
decompressed. The superior petrosal sinus was skeletonized and preserved. The dura of the posterior fossa was incised and partially excised to gain entrance to the CP angle.

A large cystic lesion was encountered whereby the contents of the cyst was evacuated to reduce the size of the tumour. Following this. there was gentle retraction of the sigmoid sinus and the cerebellum allowed better exposure of the posterior fossa. With meticulous sharp and blunt dissection, the cystic capsule was removed from the cerebellum.

The CSF was drained from the lateral and the basal cisterns to-decompress the posterior fossa. A large solid tumour was encountered within the CP angle whereby gradual debulking was carried out within the 4 tumour capsule. When this was completed, the tumour was mobilized very gently from the brain stem in the superior and the posterior boundaries. Inferiorly the tumour appeared to be stuck to the lower cranial nerves and a sliver of tumour was preserved to protect the lower cranial nerves. Superiorly.the petrosal vein was preserved and the tumour dissected gently away from it and from the trigeminalnerve.

Laterally, the tumour was removed from the internal auditory canal. Following the facial nerve. the nerve was felt to be displaced anteriorly initially and inferiorly towards the brain stem. All the tumour in this area was removed and dissected meticulously away from the facial nerve to maintain the nerve integrity and function. There was very little irritability within the facial nerve while monitored. The nerve stimulated well to bipolar stimulation at 0.01 mA. All visible tumour was removed except for a small sliver stuck up to the brainstem root at the exit zone of the lower cranial nerves. The decision was made to preserve this area and to avoid injuring the lower cranial nerves. Hemostasis was obtained throughout the procedure using bipolar coagulation and Gelfoam as well as Surgicel. There was no active bleeding and at the termination of the case and even with positive intrathoracic pressure.

The posterior fossa was repaired using temporalis fascia and abdominal fat and connective tissue obliterating middle ear space and bone wax obliterating all mastoid air cells. The abdominal fat was placed within the surgical cavity and stabilized with Tisseel. Paiva periosteal flap was returned and used to obliterate the surgical defect along with the rotation of temporalis muscle flap. The wound was closed in layers using #2.0 and #3.0 Dexon as well as skin staples. A standard dressing was applied.

Total estimated blood loss was less than 200 cc and the patient tolerated the procedure well and he was then brought to the recovery room and then extubated without difficulty.

He had excellent and normal facial nerve function in the recovery room.