Morphological changes after radiosurgery for mesial temporal lobe epilepsy.
BACKGROUND
To review our experience with morphological developments during the long-term follow-up of patients treated by Gamma Knife radiosurgery for mesial temporal lobe epilepsy.


METHODS
Between 1995 and 1999, we treated 14 patients with marginal doses of 24 Gy (n = 6) and 18-20 Gy (n = 8). Nine of these were operated on for insufficient seizure control. We reviewed seizure outcome and magnetic resonance images in both operated and unoperated patients and also re-examined histopathology specimens.


RESULTS
Of the nine operated patients, two were Engel IIIA, one was IVA, five were IVB, and one was Engel IVC prior to surgery. At their final visit, five cases had become Engel class IA, one patient was ID, and two were IIC. In one patient the follow-up was not long enough for classification. Of the five unoperated patients, one was Engel class IB, one was IIIA, one IIB and one IVB at their final visit. Radionecrosis developed in 11 patients, occurring more often and earlier in those treated with higher doses. Collateral edema reached outside the temporal lobe in six patients, caused uncal herniation in two and intracranial hypertension in three. During longer follow-up, postnecrotic pseudocysts developed in 9 patients, and postcontrast enhancement persisted for 2.5-16 years after GKRS in all 14 patients. In five of them we detected its progression between 2 and 16 years after treatment. Signs of neoangiogenesis were found in two patients and microbleeds could be seen in five. Histopathology revealed blood vessel proliferation and macrophage infiltration.


CONCLUSIONS
Early delayed complications and morphological signs suggesting a risk of development of late delayed complications are frequent after radiosurgery for mesial temporal lobe epilepsy. Together with its unproven antiseizure efficacy, these issues should be taken into account when planning future studies of this method.
Department of Neurology, Na Homolce Hospital, Roentgenova 2, 15030, Prague 5-Motol, Czech Republic. zdenek.vojtech@homolka.cz.
Zdeněk
Z
Vojtěch
Department of Radiodiagnostics, Na Homolce Hospital, Prague, Czech Republic.
Hana
H
Malíková
Department of Pathology, Na Homolce Hospital, Prague, Czech Republic.
Martin
M
Syrůček
Department of Psychology, Na Homolce Hospital, Prague, Czech Republic.
Lenka
L
Krámská
Department of Neurosurgery, Na Homolce Hospital, Prague, Czech Republic.
Jan
J
Šroubek
Department of Stereotactic and Radiation Neurosurgery, Na Homolce Hospital, Prague, Czech Republic.
Vilibald
V
Vladyka
Department of Stereotactic and Radiation Neurosurgery, Na Homolce Hospital, Prague, Czech Republic.
Roman
R
Liščák
D000293:Adolescent; D000328:Adult; D002648:Child; D004833:Epilepsy, Temporal Lobe / Q000601:surgery*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D016634:Radiosurgery / Q000009:adverse effects*; D013702:Temporal Lobe / Q000473:pathology / Q000601:surgery
Epilepsy surgery; Gamma knife; Mesial temporal sclerosis; Radionecrosis