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Shinya Watanabe, Masaaki Yamamoto, Takuya Kawabe, Takao Koiso, Tetsuya Yamamoto, Akira Matsumura and Hidetoshi Kasuya

OBJECTIVE

The aim of this study was to reappraise long-term treatment outcomes of stereotactic radiosurgery (SRS) for vestibular schwannomas (VSs). The authors used a database that included patients who underwent SRS with a unique dose-planning technique, i.e., partial tumor coverage designed to avoid excess irradiation of the facial and cochlear nerves, focusing on tumor control and hearing preservation. Clinical factors associated with post-SRS tumor control and long-term hearing preservation were also analyzed.

METHODS

This institutional review board–approved, retrospective cohort study used the authors' prospectively accumulated database. Among 207 patients who underwent Gamma Knife SRS for VSs between 1990 and 2005, 183 (who were followed up for at least 36 post-SRS months) were studied. The median tumor volume was 2.0 cm3 (range 0.05–26.2 cm3). The median prescribed dose at the tumor periphery was 12.0 Gy (range 8.8–15.0 Gy; 12.0 Gy was used in 171 patients [93%]), whereas tumor portions facing the facial and cochlear nerves were irradiated with 10.0 Gy. As a result, 72%–99% of each tumor was irradiated with the prescribed dose. The mean cochlear doses ranged from 2.3 to 5.7 Gy (median 4.1 Gy).

RESULTS

The median durations of imaging and audiometric follow-up were 114 months (interquartile range 73–144 months) and 59 months (interquartile range 33–109 months), respectively. Tumor shrinkage was documented in 110 (61%), no change in 48 (27%), and enlargement in the other 22 (12%) patients. A further procedure (FP) was required in 15 (8%) patients. Thus, the tumor growth control rate was 88% and the clinical control rate (i.e., no need for an FP) was 92%. The cumulative FP-free rates were 96%, 93%, and 87% at the 60th, 120th, and 180th post-SRS month, respectively. Six (3%) patients experienced facial pain, and 2 developed transient facial palsy. Serviceable hearing was defined as a pure tone audiogram result better than 50 dB. Among the 66 patients with serviceable hearing before SRS who were followed up, hearing acuity was preserved in 23 (35%). Actuarial serviceable hearing preservation rates were 49%, 24%, and 12% at the 60th, 120th, and 180th post-SRS month, respectively. On univariable analysis, only cystic-type tumor (HR 3.36, 95% CI 1.18–9.36; p = 0.02) was shown to have a significantly unfavorable association with FP. Multivariable analysis followed by univariable analysis revealed that higher age (≥ 65 years: HR 2.66, 95% CI 1.16–5.92; p = 0.02), larger tumor volume (≥ 8 cm3: HR 5.36, 95% CI 1.20–17.4; p = 0.03), and higher cochlear dose (mean cochlear dose > 4.2 Gy: HR 2.22, 95% CI 1.07–4.77; p = 0.03) were unfavorable factors for hearing preservation.

CONCLUSIONS

Stereotactic radiosurgery achieved good long-term results in this series. Tumor control was acceptable, and there were few serious complications in patients with small- to medium-sized VSs. Unfortunately, hearing preservation was not satisfactory. However, the longer the observation period, the more important it becomes to compare post-SRS hearing decreases with the natural decline in untreated cases.

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Yutaro Takayama, Naoki Ikegaya, Keiya Iijima, Yuiko Kimura, Norihiro Muraoka, Yuu Kaneko, Tetsuya Yamamoto and Masaki Iwasaki

OBJECTIVE

Intractable epilepsy patients with ulegyria could be candidates for resective surgery. Complete resection of ulegyria in the epileptogenic hemisphere is associated with favorable seizure outcome, although the risk of postoperative functional deficits is higher. The authors evaluated the extent of resection and postsurgical outcomes in epilepsy patients with ulegyria who underwent intracranial electroencephalography (iEEG) monitoring prior to resection to clarify the efficacy of iEEG-guided partial resection of ulegyria.

METHODS

Ten consecutive epilepsy patients with ulegyria (7 males and 3 females, age range at surgery 7–34 years) underwent iEEG prior to resective surgery between 2011 and 2017 with a minimum follow-up of 12 months (range 12–72 months). The diagnosis of ulegyria was based on the typical pattern of cortical atrophy especially at the bottom of the sulcus on MRI. An iEEG study was indicated after comprehensive preoperative evaluations, including high-field MRI, long-term video-EEG, magnetoencephalography, and FDG-PET. The resection planning was based on iEEG analysis. Total lesionectomy was not always performed, as preservation of cortical function was prioritized.

RESULTS

Ulegyria was seen in the occipital and/or parietal lobe in 9 patients and bilaterally in 5 patients. Ictal EEG onset involved the temporal neocortex in 6 patients. Intracranial electrodes were implanted unilaterally in all except 1 patient with bilateral lesions. The extent of MRI lesion was covered by the electrodes. Seizure onset zones (SOZs) and irritative zones (IZs) were identified in all patients. SOZs and IZs were completely resected in 8 patients but were only partially removed in the remaining 2 patients because the eloquent cortices and the epileptogenic zones overlapped. Ulegyria of the epileptogenic side was totally resected in 1 patient. Seizure freedom was achieved in 4 patients, including 3 after partial lesionectomy. Extended resection of the temporal neocortex was performed in 4 patients, although postoperative seizure freedom was achieved only in 1 of these patients. Visual field deficit was seen in 4 patients. Three of 5 patients with bilateral lesions achieved seizure freedom after unilateral resective surgery.

CONCLUSIONS

Intracranial EEG–guided partial lesionectomy provides a reasonable chance of postoperative seizure freedom with a lower risk of functional deficits. Patients with bilateral ulegyria should not be excluded from consideration as surgical candidates.

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Hitoshi Aiyama, Masaaki Yamamoto, Takuya Kawabe, Shinya Watanabe, Takao Koiso, Yasunori Sato, Yoshinori Higuchi, Eiichi Ishikawa, Tetsuya Yamamoto, Akira Matsumura and Hidetoshi Kasuya

OBJECTIVE

Although the conformity index (CI) and the gradient index (GI), which were proposed by Paddick and colleagues, are both logically considered to correlate with good posttreatment results after stereotactic radiosurgery (SRS), this hypothesis has not been confirmed clinically. The authors’ aim was to reappraise whether high CI values correlate with reduced tumor progression rates, and whether low GI values correlate with reduced complication incidences.

METHODS

This was an institutional review board–approved, retrospective cohort study conducted using a prospectively accumulated database including 3271 patients who underwent Gamma Knife SRS for brain metastases (BMs) during the 1998–2016 period. Among the 3271 patients, 925 with a single BM at the time of SRS (335 women and 590 men, mean age 66 [range 24–93] years) were studied. The mean/median CIs were 0.62/0.66 (interquartile range [IQR] 0.53–0.74, range 0.08–0.88) and the mean/median GIs were 3.20/3.09 (IQR 2.83–3.39, range 2.27–11.4).

RESULTS

SRS-related complications occurred in 38 patients (4.1%), with a median post-SRS interval of 11.5 (IQR 6.0–25.8, maximum 118.0) months. Cumulative incidences of post-SRS complications determined by a competing risk analysis were 2.2%, 3.2%, 3.6%, 3.8%, and 3.9% at the 12th, 24th, 36th, 48th, and 60th post-SRS month, respectively. Multivariable analyses showed that only two clinical factors (i.e., peripheral doses and brain volume receiving ≥ 12 Gy) correlated with complication rates. However, neither CIs nor GIs impacted the incidences of complications. Among the 925 patients, post-SRS MRI was performed at least once in 716 of them, who were thus eligible for local progression evaluation. Among these 716 patients, local progression was confirmed in 96 (13.4%), with a median post-SRS interval of 10.8 (IQR 6.7–19.5, maximum 59.8) months. Cumulative incidences of local progression determined by a competing risk analysis were 7.7%, 12.6%, 14.2%, 14.8%, and 15.3% at the 12th, 24th, 36th, 48th, and 60th post-SRS month, respectively. Multivariable analyses showed neurological symptoms, extracerebral metastases, repeat SRS, and CIs to correlate with incidences of local progression, whereas GIs had no impact on local tumor progression. Particularly, cumulative incidences of local progression were significantly lower in patients with CIs < 0.65 than in those with CIs ≥ 0.65 (adjusted hazard ratio 1.870, 95% confidence interval 1.299–2.843; p = 0.0034).

CONCLUSIONS

To the authors’ knowledge, this is the first analysis to focus on the clinical significance of CI and GI based on a large series of patients with BM. Contrary to the majority opinion that dose planning with higher CI and lower GI results in good post-SRS outcomes (i.e., low local progression rates and minimal complications), this study clearly showed that the lower the CIs were, the lower the local progression rates were, and that the GI did not impact complication rates.

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Takao Koiso, Masaaki Yamamoto, Takuya Kawabe, Shinya Watanabe, Yasunori Sato, Yoshinori Higuchi, Tetsuya Yamamoto, Akira Matsumura and Hidetoshi Kasuya

OBJECTIVE

Stereotactic radiosurgery (SRS) without upfront whole-brain radiotherapy (WBRT) has influenced recent treatment recommendations for brain metastasis patients. However, in brain metastasis patients who undergo SRS alone, new brain metastases inevitably appear with relatively high incidences during post-SRS follow-up. However, little is known about the second SRS results. The treatment results of second SRS were retrospectively reviewed, mainly for newly developed or, uncommonly, for recurrent brain metastases in order to reappraise the efficacy of this treatment strategy with a special focus on the maintenance of neurological status and safety.

METHODS

This was an institutional review board–approved, retrospective cohort study that used a prospectively accumulated database, including 3102 consecutive patients with brain metastases who underwent SRS between July 1998 and June 2015. Among these 3102 patients, 859 (376 female patients; median age 64 years; range 21–88 years) who underwent a second SRS without WBRT were studied with a focus on overall survival, neurological death, neurological deterioration, local recurrence, salvage SRS, and SRS-induced complications after the second SRS. Before the second SRS, the authors also investigated the clinical factors and radiosurgical parameters likely to influence these clinical outcomes. For the statistical analysis, the standard Kaplan-Meier method was used to determine post–second SRS survival and neurological death. A competing risk analysis was applied to estimate post–second SRS cumulative incidences of local recurrence, neurological deterioration, salvage SRS, and SRS-induced complications.

RESULTS

The post–second SRS median survival time was 7.4 months (95% CI 7.0–8.2 months). The actuarial survival rates were 58.2% and 34.7% at 6 and 12 months after the second SRS, respectively. Among 789 deceased patients, the causes of death could not be determined in 24 patients, but were confirmed in the remaining 765 patients to be nonbrain diseases in 654 (85.5%) patients and brain diseases in 111 (14.5%) patients. The actuarial neurological death–free survival rates were 94.4% and 86.6% at 6 and 12 months following the second SRS. Multivariable analysis revealed female sex, Karnofsky Performance Scale score of 80% or greater, better modified recursive partitioning analysis class, smaller tumor numbers, and higher peripheral dose to be significant predictive factors for longer survival. The cumulative incidences of local recurrence were 11.2% and 14.9% at 12 and 24 months after the second SRS. The crude incidence of neurological deterioration was 7.1%, and the respective cumulative incidences were 4.5%, 5.8%, 6.7%, 7.2%, and 7.5% at 12, 24, 36, 48, and 60 months after the second SRS. SRS-induced complications occurred in 25 patients (2.9%) after a median post–second SRS period of 16.8 months (range 0.6–95.0 months; interquartile range 5.6–29.3 months). The cumulative incidences of complications were 1.4%, 2.0%, 2.4%, 3.0%, and 3.0% at 12, 24, 36, 48, and 60 months after the second SRS, respectively.

CONCLUSIONS

Carefully selected patients with recurrent tumors—either new or locally recurrent—are favorable candidates for a second SRS, particularly in terms of neurological status maintenance and the safety of this treatment strategy.

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Shinya Watanabe, Masaaki Yamamoto, Yasunori Sato, Takuya Kawabe, Yoshinori Higuchi, Hidetoshi Kasuya, Tetsuya Yamamoto, Akira Matsumura and Bierta E. Barfod

Object

Recently, an increasing number of patients with brain metastases, even patients over 80 years of age, have been treated with stereotactic radiosurgery (SRS). However, there is little information on SRS treatment results for patients with brain metastases 80 years of age and older. The authors undertook this study to reappraise whether SRS treatment results for patients 80 years of age or older differ from those of patients who are 65–79 years old.

Methods

This was an institutional review board–approved, retrospective cohort study. Among 2552 consecutive brain metastasis patients who underwent SRS during the 1998–2011 period, we studied 165 who were 80 years of age or older (Group A) and 1181 who were age 65–79 years old (Group B). Because of the remarkable disproportion in patient numbers between the 2 groups and considerable differences in pre-SRS clinical factors, the authors conducted a case-matched study using the propensity score matching method. Ultimately, 330 patients (165 from each group, A and B) were selected. For time-to-event outcomes, the Kaplan-Meier method was used to estimate overall survival and competing risk analysis was used to estimate other study end points, as appropriate.

Results

Although the case-matched study showed that post-SRS median survival time (MST, months) was shorter in Group A patients (5.3 months, 95% CI 3.9–7.0 months) than in Group B patients (6.9 months, 95% CI 5.0–8.1 months), this difference was not statistically significant (HR 1.147, 95% CI 0.921–1.429, p = 0.22). Incidences of neurological death and deterioration were slightly lower in Group A than in Group B patients (6.3% vs 11.8% and 8.5% vs 13.9%), but these differences did not reach statistical significance (p = 0.11 and p = 0.16). Furthermore, competing risk analyses showed that the 2 groups did not differ significantly in cumulative incidence of local recurrence (HR 0.830, 95% CI 0.268–2.573, p = 0.75), rates of repeat SRS (HR 0.738, 95% CI 0.438–1.242, p = 0.25), or incidence of SRS-related complications (HR 0.616, 95% CI 0.152–2.495, p = 0.49). Among the Group A patients, post-SRS MSTs were 11.6 months (95% CI 7.8–19.6 months), 7.9 months (95% CI 5.2–10.9 months), and 2.8 months (95% CI; 2.4–4.6 months) in patients whose disease status was modified–recursive partitioning analysis (RPA) Class(es) I+IIa, IIb, and IIc+III, respectively (p < 0.001).

Conclusions

Our results suggest that patients 80 years of age or older are not unfavorable candidates for SRS as compared with those 65–79 years old. Particularly, even among patients 80 years and older, those with modified-RPA Class I+IIa or IIb disease are considered to be favorable candidates for more aggressive treatment of brain metastases.

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Yosuke Masuda, Hiroyoshi Akutsu, Eiichi Ishikawa, Masahide Matsuda, Tomohiko Masumoto, Takashi Hiyama, Tetsuya Yamamoto, Hidehiro Kohzuki, Shingo Takano and Akira Matsumura

OBJECTIVE

MRI scans obtained within 48–72 hours (early postoperative MRI [epMRI]), prior to any postoperative reactive changes, are recommended for the accurate assessment of the extent of resection (EOR) after glioma surgery. Diffusion-weighted imaging (DWI) enables ischemic lesions to be detected and distinguished from the residual tumor. Prior studies, however, revealed that postoperative reactive changes were often present, even in epMRI. Although intraoperative MRI (iMRI) is widely used to maximize safe resection during glioma surgery, it is unclear whether iMRI is superior to epMRI when evaluating the EOR, because it theoretically shows fewer postoperative reactive changes. In addition, the ability to detect ischemic lesions using iMRI has not been investigated.

METHODS

The authors retrospectively analyzed prospectively collected data in 30 patients with glioma (22 and 8 patients with enhancing and nonenhancing lesions, respectively) who underwent tumor resection. These patients had received preoperative MRI within 24 hours prior to surgery, postresection radiological evaluation with iMRI during surgery, and epMRI within 24 hours after surgery, with all neuroimaging performed using identical 1.5T MRI scanners. The authors compared iMRI or epMRI with preoperative MRI, and defined a postoperative reactive change as a new postoperative enhancement or T2 high-intensity area (HIA), if this lesion was outside of the preoperative original tumor location. In addition, postoperative ischemia was evaluated on DWI. The iMRI and epMRI findings were compared in terms of 1) postoperative reactive changes, 2) evaluation of the EOR, and 3) presence of ischemic lesion on DWI.

RESULTS

In patients with enhancing lesions, a new enhancement was seen in 8 of 22 patients (36.4%) on iMRI and in 12 of 22 patients (54.5%) on epMRI. In patients with nonenhancing lesions, a new T2 HIA was seen in 4 of 8 patients (50.0%) on iMRI and in 7 of 8 patients (87.5%) on epMRI. A discrepancy between the EOR measured on iMRI and epMRI was noted in 5 of the 22 patients (22.7%) with enhancing lesions, and in 3 of the 8 patients (37.5%) with nonenhancing lesions. The occurrence of ischemic lesions on DWI was found in 5 of 30 patients (16.7%) on iMRI, whereas it was found in 16 of 30 patients (53.3%) on epMRI (p = 0.003); ischemic lesions were underestimated on iMRI in 11 patients.

CONCLUSIONS

Overall, given the lower incidence of postoperative reactive changes on iMRI, it was superior to epMRI in evaluating the EOR in patients with glioma, both with enhancing and nonenhancing lesions. However, because ischemic lesions can be overlooked on iMRI, the authors recommend only the additional DWI scan during the early postoperative period. Clinicians need to be mindful about not overestimating the presence of residual tumor on epMRI due to the high incidence of postoperative reactive changes.

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Satoru Osuka, Akira Matsushita, Eiichi Ishikawa, Kousaku Saotome, Tetsuya Yamamoto, Aiki Marushima, Naoaki Satou, Alexander Zaboronok, Tomohiko Masumoto and Akira Matsumura

Object

For several decades, clinicians have predicted intraparenchymal brain pressure or brain tissue compression indirectly based on the degree of distortion of the midline structures (midline shift) and ventricle wall (ventriculomegaly) observed on conventional MRI. However, this method has several limitations. Diffusion tensor imaging (DTI) is a novel MRI technique that can provide information about the microstructural properties of compressed tissue. In this study, the authors evaluated whether DTI can precisely define the degree of tissue compression in patients with chronic subdural hematoma (CSDH).

Methods

The study sample consisted of 18 patients (mean age 71 years, 10 men and 8 women) with unilateral CSDH and 12 age-matched volunteers. Diffusion tensor imaging results were acquired before and after the surgical irrigation in the CSDH group. Subdural pressure during the operation was also measured. Fractional anisotropy (FA) values were evaluated at several locations, including the gray matter.

Results

The FA values of the gray matter, especially in the caudate nucleus and putamen, were increased in the patients with CSDH compared with the control group. The change in FA data before and after surgery (ΔFA) correlated with the degree of tissue compression evaluated by measurement of the subdural pressure. Furthermore, the increased FA values in patients with CSDH decreased after surgery.

Conclusions

These findings indicate that FA values of the gray matter, especially in the caudate nucleus and putamen, may be important markers of tissue compression. The assessment of FA values of the gray matter will result in a new, less-invasive diagnostic technique to evaluate the degree of brain compression.

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Miyuki Fukuda, Shunichi Fukuda, Joji Ando, Kimiko Yamamoto, Naohiro Yonemoto, Takashi Suzuki, Youko Niwa, Takayuki Inoue, Noriko Satoh-Asahara, Koji Hasegawa, Akira Shimatsu and Tetsuya Tsukahara

OBJECTIVE

There are no effective therapeutic drugs for cerebral aneurysms, partly because the pathogenesis remains unresolved. Chronic inflammation of the cerebral arterial wall plays an important role in aneurysm formation, but it is not clear what triggers the inflammation. The authors have observed that vascular endothelial P2X4 purinoceptor is involved in flow-sensitive mechanisms that regulate vascular remodeling. They have thus hypothesized that shear stress–associated hemodynamic stress on the endothelium causes the inflammatory process in the cerebral aneurysm development.

METHODS

To test their hypothesis, the authors examined the role of P2X4 in cerebral aneurysm development by using P2X4 / mice and rats that were treated with a P2X4 inhibitor, paroxetine, and subjected to aneurysm-inducing surgery. Cerebral aneurysms were induced by unilateral carotid artery ligation and renovascular hypertension.

RESULTS

The frequency of aneurysm induction evaluated by light microscopy was significantly lower in the P2X4 / mice (p = 0.0488) and in the paroxetine-treated male (p = 0.0253) and female (p = 0.0204) rats compared to control mice and rats, respectively. In addition, application of paroxetine from 2 weeks after surgery led to a significant reduction in aneurysm size in the rats euthanized 3 weeks after aneurysm-inducing surgery (p = 0.0145), indicating that paroxetine suppressed enlargement of formed aneurysms. The mRNA and protein expression levels of known inflammatory contributors to aneurysm formation (monocyte chemoattractant protein–1 [MCP-1], interleukin-1β [IL-1β], tumor necrosis factor–α [TNFα], inducible nitric oxide synthase [iNOS], and cyclooxygenase-2 [COX-2]) were all significantly elevated in the rats that underwent the aneurysm-inducing surgery compared to the nonsurgical group, and the values in the surgical group were all significantly decreased by paroxetine administration according to quantitative polymerase chain reaction techniques and Western blotting. Although immunolabeling densities for COX-2, iNOS, and MCP-1 were not readily observed in the nonsurgical mouse groups, such densities were clearly seen in the arterial wall of P2X4 +/+ mice after aneurysm-inducing surgery. In contrast, in the P2X4 / mice after the surgery, immunolabeling of COX-2 and iNOS was not observed in the arterial wall, whereas that of MCP-1 was readily observed in the adventitia, but not the intima.

CONCLUSIONS

These data suggest that P2X4 is required for the inflammation that contributes to both cerebral aneurysm formation and growth. Enhanced shear stress–associated hemodynamic stress on the vascular endothelium may trigger cerebral aneurysm development. Paroxetine may have potential for the clinical treatment of cerebral aneurysms, given that this agent exhibits efficacy as a clinical antidepressant.

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Satoru Osuka, Akira Matsushita, Tetsuya Yamamoto, Kousaku Saotome, Tomonori Isobe, Yasushi Nagatomo, Tomohiko Masumoto, Yoji Komatsu, Eiichi Ishikawa and Akira Matsumura

Object

Ventriculomegaly is a common imaging finding in many types of conditions. It is difficult to determine whether it is related to true hydrocephalus or to an atrophic process by using only imaging procedures such as MR imaging after traumatic injury, stroke, or infectious disease. Diffusion tensor (DT) imaging can distinguish the compression characteristics of white matter, indicating that increased diffusion anisotropy may be related to white matter compression. In this preliminary study, the authors compared the DT imaging findings of ventriculomegaly with those of chronic hydrocephalus or atrophy to clarify the potential of diffusion anisotropy in the identification of hydrocephalus.

Methods

Ten patients with chronic hydrocephalus, 8 patients with atrophy (defined by conventional devices and surgical outcome), and 14 healthy volunteers underwent DT imaging. Images were acquired before and after shunting or once in cases without shunting. The fractional anisotropy (FA) values at many points around the lateral ventricle were evaluated.

Results

The FA patterns around the lateral ventricle in the chronic hydrocephalus and atrophy groups were different. Especially in the caudate nucleus, FA was increased in the chronic hydrocephalus group compared with the atrophy group. Furthermore, the FA values returned to normal levels after shunt placement.

Conclusions

Assessment of the FA value of the caudate nucleus may be an important, less invasive method for distinguishing true hydrocephalus from ventriculomegaly. Further research in a large number of patients is needed to verify the diagnostic ability of this method.

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Naoki Ikegaya, Masaki Iwasaki, Yuu Kaneko, Takanobu Kaido, Yuiko Kimura, Tetsuya Yamamoto, Noriko Sumitomo, Takashi Saito, Eiji Nakagawa, Kenji Sugai, Masayuki Sasaki, Akio Takahashi and Taisuke Otsuki

OBJECTIVE

Cognitive risk associated with insular cortex resection is not well understood. The authors reviewed cognitive and developmental outcomes in pediatric patients who underwent resection of the epileptogenic zone involving the insula.

METHODS

A review was conducted of 15 patients who underwent resective epilepsy surgery involving the insular cortex for focal cortical dysplasia, with a minimum follow-up of 12 months. The median age at surgery was 5.6 years (range 0.3–13.6 years). Developmental/intelligence quotient (DQ/IQ) scores were evaluated before surgery, within 4 months after surgery, and at 12 months or more after surgery. Repeated measures multivariate ANOVA was used to evaluate the effects on outcomes of the within-subject factor (time) and between-subject factors (resection side, anterior insular resection, seizure control, and antiepileptic drug [AED] reduction).

RESULTS

The mean preoperative DQ/IQ score was 60.7 ± 22.8. Left-side resection and anterior insular resection were performed in 9 patients each. Favorable seizure control (International League Against Epilepsy class 1–3) was achieved in 8 patients. Postoperative motor deficits were observed in 9 patients (permanent in 6, transient in 3). Within-subject changes in DQ/IQ were not significantly affected by insular resection (p = 0.13). Postoperative changes in DQ/IQ were not significantly affected by surgical side, anterior insular resection, AED reduction, or seizure outcome. Only verbal function showed no significant changes before and after surgery and no significant effects of within-subject factors.

CONCLUSIONS

Resection involving the insula in children with impaired development or intelligence can be performed without significant reduction in DQ/IQ, but carries the risk of postoperative motor deficits.