Operculoinsular cortectomy for refractory epilepsy. Part 2: Is it safe?

Abstract

<jats:sec><jats:title>OBJECTIVE</jats:title><jats:p>Operculoinsular cortectomy (also termed operculoinsulectomy) is increasingly recognized as a therapeutic option for perisylvian refractory epilepsy. However, most neurosurgeons are reluctant to perform the technique because of previously experienced or feared neurological complications. The goal of this study was to quantify the incidence of basic neurological complications (loss of primary nonneuropsychological functions) associated with operculoinsular cortectomies for refractory epilepsy, and to identify factors predicting these complications.</jats:p></jats:sec><jats:sec><jats:title>METHODS</jats:title><jats:p>Clinical, imaging, and surgical data of all patients investigated and surgically treated by our team for refractory epilepsy requiring an operculoinsular cortectomy were retrospectively reviewed. Patients with tumors and encephalitis were excluded. Logistic regression analysis was used for uni- and multivariate statistical analyses.</jats:p></jats:sec><jats:sec><jats:title>RESULTS</jats:title><jats:p>Forty-four operculoinsular cortectomies were performed in 43 patients. Although postoperative neurological deficits were frequent (54.5% of procedures), only 3 procedures were associated with a permanent significant neurological deficit. Out of the 3 permanent deficits, only 1 (2.3%; a sensorimotor hemisyndrome) was related to the technique of operculoinsular cortectomy (injury to a middle cerebral artery branch), while the other 2 (arm hypoesthesia and hemianopia) were attributed to cortical resection beyond the operculoinsular area. With multivariate analysis, a postoperative neurological deficit was associated with preoperative insular hypometabolism on PET scan. Postoperative motor deficit (29.6% of procedures) was correlated with fewer years of neurosurgical experience and frontal operculectomies, but not with corona radiata ischemic lesions. Ischemic lesions in the posterior two-thirds of the corona radiata (40.9% of procedures) were associated with parietal operculectomies, but not with posterior insulectomies.</jats:p></jats:sec><jats:sec><jats:title>CONCLUSIONS</jats:title><jats:p>Operculoinsular cortectomy for refractory epilepsy is a relatively safe therapeutic option but temporary neurological deficits after surgery are frequent. This study highlights the role of frontal/parietal opercula resections in postoperative complications. Corona radiata ischemic lesions are not clearly related to motor deficits. There were no obvious permanent neurological consequences of losing a part of an epileptic insula, including on the dominant side for language. A low complication rate can be achieved if the following conditions are met: 1) microsurgical technique is applied to spare cortical branches of the middle cerebral artery; 2) the resection of an opercula is done only if the opercula is part of the epileptic focus; and 3) the neurosurgeon involved has proper training and experience.</jats:p></jats:sec>

Predictors of outcomes after surgery for medically intractable insular epilepsy: A systematic review and individual participant data meta‐analysis

“…Resections sparing this region have been shown to avoid motor deficits, albeit at the expense of incomplete EZ removal and reduced seizure freedom 24 . It is therefore conceivable that the high incidence of motor deficits observed in our study may be related to ischemic lesions to the corona radiata, and this is further supported by a recent study revealing a 60% rate of corona radiata strokes following insular surgeries for refractory epilepsy 37,38 . The strongest predictor of motor deficit identified in our study was resection of the frontal operculum, which is consistent with the largest series of surgery for IE 37 .…”

“…Motor and language deficits may arise directly from microsurgical resection, transgression, or retraction of functional peri‐Sylvian cortical regions or indirectly from cortical or subcortical middle cerebral artery (MCA)‐territory ischemic stroke. 37 , 38 , 39 While major technological advances have made microsurgical resection for IE safer, permanent neurological impairment (eg, hemiplegia) rates exceed 20% in some contemporary series. 32 , 40 …”

Comparison of the real‐world effectiveness of vertical versus lateral functional hemispherotomy techniques for pediatric drug‐resistant epilepsy: A post hoc analysis of the HOPS study

“… 28 , 34 Epilepsy program and surgical experience has been shown to play a significant role in obtaining a complete anatomical disconnection and obtaining higher likelihood of seizure freedom and better outcome. 35 , 36 , 37 Although this variable was not explicitly studied in this analysis, the learning curve could potentially explain the higher seizure recurrence rate in lateral than in vertical hemispherotomies.…”

Heart Rate Variability in Insulo-Opercular Epilepsy

“…The role of the insula in drug-resistant epilepsy has been increasingly recognized with the report of several cases of insular, insulo-opercular or temporo-insular epilepsy successfully treated by resection, radio-frequency thermocoagulation, or laser ablation [1][2][3][4][5][6]. Because of the insula's implication in autonomic regulation, which is supported by the insular electrical stimulation [7,8], a few studies have looked at possible evidence of autonomic dysfunction in insular epilepsy, with some authors even suggesting a higher risk of Sudden Unexpected Death in Epilepsy (SUDEP) [9,10].…”