gms | German Medical Science

Objective: To analyze pre-operative symptoms and late clinical outcome in patients who underwent surgical treatment of arterio-venous malformations (AVMs) of the temporal lobe, including those involving the Sylvian fissure (SF) and the lateral wall of the inferior ventricular horns – with special respect to post-operative hemiparesis and visual field defects (VFD).

Methods: Between 1992 and 2007, n=44 patients (n=22 f, n=22 m) with a mean age of 41 (12–67) years were operated on an AVM of the temporal lobe. All data had been collected prospectively. Patients' charts, as well as surgical reports and outpatient files were analyzed. Thirteen patients showed an involvement of the SF, and 6 were localized partially in the lateral wall of the temporal horn. Eight AVMs were located in the temporo-mesial region. Fourteen patients had an AVM located mainly within the visual pathway. In 24 cases the AVM was located in the dominant hemisphere. The AVMs were classified by the Spetzler-Martin grading system (SM). Visual fields were assessed in all patients pre-and post-operatively by independent ophthalmological examiners.

Results: Initial symptoms were seizures in 48%, hemorrhage in 23%, headache in 18%, whereas the AVMs were found incidentally in 11%. Based on SM, n=7 AVMs were grade I, n=17 grade II, n=17 grade III, and n=3 grade IV. Pre-operatively, n=7 patients presented with a VFD and 2 with a hemiparesis. Post-operatively, n=8/44 (18%) patients presented with a new hemiparesis, remaining permanent in 3/44 (7%). In n=2 of these patients the AVMs were localized temporo-mesially (n=2/8, 25%). N=7 patients (19%) showed a new significant post-operative VFD, and, in addition, n=2 patients had worsening of their pre-existing VFD (2/7, 29%). Post-operative angiography verified complete AVM occlusion in 43/44 (98%) cases.

Conclusions: Treatment of temporal lobe AVMs is demanding due to their close spatio-anatomical relationship with important neurovascular structures and the optic radiation. In this surgically treated series morbidity for a new permanent hemiparesis was 7% and preservation of the visual field could be achieved in 80% of all cases. This is a calculable risk for most patients that renders microsurgical resection a justifiable option, even in the light of other treatment modalities. The risk for new permanent motor deficits is elevated in temporo-mesial AVMs, and these patients have to be consulted accordingly for surgical treatment.