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Arteriovenous Malformation (AVM)

Patient: A 33-year-old female was admitted to our neurosurgery service after presenting to a community hospital with headache, lethargy, nausea and vomiting.

Presenting Problem: Her work-up revealed intra ventricular hemorrhage, with subsequent placement of a ventricular shunt. Angiography was positive for arteriovenous malformation in the left posterior cerebral artery territory. She managed nonoperatively and two weeks later was transferred for inpatient rehabilitation for impairment of ambulation, inability with self-care, and severe cognitive deficit.

At her three month follow-up, she shows significant improvement neurologically due to rehabilitation and with outpatient physical therapy. She has no headaches or seizures. Her cognition and memory are improving daily. Speech, motor, cerebellar testing, sensory examine, gait and station all were normal.

We discussed options for dealing with the arteriovenous malformation with her and her husband. They were: microsurgery, embolization therapy, a combination of embolization and microsurgery, Gamma Knife radiosurgery, and no specific therapy. The advantages and disadvantages of each of these approaches were outlined.

Given the position of the AVM and her pending improvement neurologically, the best treatment would be Gamma Knife radiosurgery. The risks of radiosurgery were discussed with an emphasis on radiation injury, possible paralysis, visual impairment, cranial nerve palsy, stroke and the risk of recurrent hemorrhage, during the latency period for the effect of the Gamma Knife.

They understood that the chances that the lesion would respond were about 85% and not 100% and wanted to proceed with radiosurgery.

Radiosurgery Treatment: Six weeks later the patient was taken to the Gamma Knife suite and the Leksell frame was fixed to her head using local infiltration anesthesia with 0.25% marcaine. The surface topography measurements were taken and entered into the plan. A spiral CT scan and cerebral angiogram were obtained. The data from each of these were also entered into the planning computer; the target was outlined on the spiral CT in conjunction with the outline that had been drawn by the radiologist, and was found to correlate well with the two-dimensional projections of the angiogram, and the MR scan with findings of a 2.1 x 1.1 arteriovenous malformation in the medial aspect of the left temporal lobe.

Shots were then placed in the target area, and after working the plan, we were able to achieve very good coverage, with good ratios. The 1000 C line was noted to be just outside the brainstem. A dose of 20.0 Gy to the 50% isodose line at the margin of the target.

A plan consisting of seven shots was devised. The plan was then delivered without complication and the patient tolerated the procedure well. She was given instructions regarding the possibility that she could have a seizure and was told to call if she had any new neurological symptoms.

Clinical Outcome: Six months status post Gamma Knife radiosurgery, the patient returned for evaluation of a left inferior-temporal/parietal malformation. She has made a very good recovery from her hemorrhage and progressively improves with her memory and all other neurological functions. The patient has had no seizure activity to date. An angiogram will be repeated at 18 months status post Gamma Knife.

At 18 months status post Gamma Knife, a follow up angiogram showed, mild prominence of the left middle cerebral artery branches with no prominent draining veins or residual nidus to indicate residual arteriovenous malformation. The patient is doing well - no hemorrhage, no seizures, and her speech is normal, visual fields normal, motor skills and sensory examination normal with no pathological reflexes.

Annual follow-ups demonstrate no evidence of residual or recurrent arteriovenous malformations. No abnormalities are identified.