Improvement and Deterioration of Seizure Control During the Postsurgical Course of Epilepsy Surgery Patients

Abstract

Summary:Purpose: To determine the factors associated with changes in seizure control during the postsurgical course of epilepsy surgery patients.Methods: Evaluation of patients after consecutive temporal and frontal resection whose seizure frequency was scored for each year of postsurgical follow-up. In each cohort, patients with a change in their seizure control after the first postsurgical year were compared with control subjects to determine factors that may be responsible for the change.Results: Thirty-three (15%) of 214 temporal lobectomy versus 12 (20%) of 59 frontal resection patients experienced a change in seizure control (p > 0.05). Ten (5%) of 214 temporal lobectomy versus nine (15%) of 59 frontal resection patients experienced an improvement in seizure control (p = 0.009), but 23 ( I 1%) of 214 temporal lobectomy versus three (5%) of 59 frontal resection patients had a worsening in seizure control (p > 0.05). In temporal lobectomy patients, preoperative unilateral temporal epileptiform discharges were associated with improvement (p = 0.03), whereas older age at surgery was associated with worsening of seizure control (p = 0.007). In frontal resection patients, presence of a congenital central nervous system (CNS) anomaly was associated with late improvement in seizure control (p = 0.006).Conclusion: During the postsurgical course, an improvement in seizure control is more common after frontal resection than after temporal lobectomy. Factors associated with improvement are the presence of a congenital CNS abnormality in frontal resection patients, and the occurrence of preoperative unilateral epileptiform discharges in temporal lobectomy patients. Older age at temporal lobectomy may be associated with greater risk of worsening seizure control.

Predicting long-term seizure outcome after resective epilepsy surgery

“…While we did not find a significant difference in remission rates between medial temporal and neocortical resection groups, the number of neocortical surgery patients was too small to have the power to detect moderate differences between these groups, and we cannot rule out a two and a half fold difference in those remission rates. Most earlier reports that contrasted results in different cortical regions suggested better remission rates for medial temporal resections, 4,14,15,19,21,28 although much of the literature on surgical outcome addressed only temporal resections. 1-6,10-12,17,23,24 Regardless, these overall statistics are heartening, and speak for the utility of such procedures, especially in light of the refractory nature of the seizures in patients who seek surgical treatment.…”

“…This observation is also at odds with some but not all prior reports, which mostly suggested a higher relapse rate (at least after 1 year of seizure freedom) in mesial temporal vs neocortical resected patients. 1,[3][4][5][6]10,12,15,[16][17][18][19][20][21][22] Although the estimate of effect suggests little difference in relapse after remission in medial temporal vs neocortical resected patients, we still cannot rule out a substantially higher risk in the medial temporal group, or a relative doubling of the risk in the neocortical group, because of the small number of neocortical resections.…”

“…[1][2][3][4][5][6][7][8][9][10][11][12][13][14][15] Extended follow-up, however, also demonstrates cumulative relapse rates up to 25%, and results are inconsistent with respect to whether these relapses occur more often after medial temporal resections. 1,[3][4][5][6]10,12,[16][17][18][19][20][21][22] Furthermore, factors predicting both remission and relapse in one sample have proved difficult to identify or confirm in others. 1,17,[23][24][25][26][27][28][29][30] Eclectic definitions of seizure outcome, variable methods of documenting seizures postoperatively, small sizes of populations used in retrospective analyses, evolution of selection criteria in the decades over which patients were selected, or the variable surgical approaches utilized might account for these inconsistencies.…”

Surgical Effects of Focus Resection for Patients With Intractable Epilepsy

“…Age at surgery and duration of epilepsy both had significant effects on seizure cessation in univariate analysis. 4,8,12) Short seizure duration was an important factor for seizure-free, off-drug outcome in patients with TLE. 10) However, a regression analysis found none of these timing-related factors had any effect on outcome or age, and no association was found between seizure onset and postoperative seizure recurrence.…”

“…[1][2][3][4][5][6]9,11,[13][14][15]17,19) These problems have recently become a focus of interest, as intractable epilepsy is recognized as a chronic encephalopathy in which one seizure induces other seizures. 7) Therefore, we need to analyze the overall effects on the quality of life to demonstrate the benefits of surgery.…”