Hammock Middle Cerebral Artery and Delayed Infarction in Lenticulostriate Artery After Staged Resection of Giant Insular Glioma

Incidence of ischemic complications and technical nuances of arteries preservation for insular gliomas resection

Introduction

Insular gliomas have complex anatomy and microvascular supply that make resection difficult. Furthermore, resection of insular glioma is associated with a significant risk of postoperative ischemic complications. Thus, this study aimed to assess the incidence of ischemic complications related to insular glioma resection, determine its risk factors, and describe a single surgeon's experience of artery-preserving tumor resection.

Methods

We enrolled 75 consecutive patients with insular gliomas who underwent transcortical tumor resection. Preoperative and postoperative demographic, clinical, radiological [including diffusion-weighted imaging (DWI)], intraoperative neurophysiological data, and functional outcomes were analyzed. Motor evoked potentials (MEPs) and radiological characteristics like the relationship between the proximal segment of the lateral lenticulostriate arteries (LLSAs) and the tumor, the flat inner edge sign (the inner edge of the insular glioma is well-defined) or obscure inner edge sign, the distance between the lesion and posterior limb of the internal capsule and the invasion of the superior limiting sulcus by the tumor were analyzed. Strategies such as "residual triangle," "basal ganglia outline reappearance," and "sculpting" technique were used to preserve the LLSAs and the main branches of M2 for maximal tumor resection according to the Berger-Sinai classification.

Results

Postoperative DWI showed acute ischemia in 44 patients (58.7%). Moreover, nine patients (12%) had developed new motor deficits, as determined by the treating neurosurgeons. The flat inner edge sign [odds ratio (OR), 0.144; 95% confidence interval (CI), 0.024-0.876) and MEPs (>50%) (OR, 18.182; 95% CI, 3.311-100.00) were significantly associated with postoperative core ischemia, which affected the posterior limb of the internal capsule or corona radiata.

Conclusions

Insular glioma resection was associated with a high incidence of ischemia, as detected by DWI, as well as new motor deficits that were determined by the treating neurosurgeons. Insular glioma patients with obscure inner edge signs and intraoperative MEPs decline >50% had a higher risk of developing core ischemia. With our strategies, maximal safe resection of insular gliomas may be achieved.

Lacunar Infarction Caused by Chronic Subdural Hematoma

In chronic subdural hematoma (CSDH) patients, motor functions usually recover quickly after burr-hole surgery; however, in a rare case, the hemiparesis showed poor improvement after surgery. In that case, investigation of cerebral infarctions is important. Among the 284 CSDH patients with motor weakness, magnetic resonance image (MRI) and MR angiography (MRA) were acquired in 82 patients before surgery when the hemiparesis progressed rapidly. Small lacunar infarction was identified on the hematoma side in five cases; all were older than 80 years with hypertension, and diabetes mellitus had been diagnosed in two. In all the five patients (100%), MRA demonstrated a downward or upward shift of the M1 portion of the middle cerebral artery on the hematoma side, where the perforating arteries originate. Conversely, only 4 CSDH patients (5.2%) without lacunar infarction demonstrated M1 downward shift. The risk factors of lacunar infarction were high in the five detected cases; however, distortion, twisting, or elongation of the lenticulostriate arteries might be a cause of the lacunar infarctions, rather than the formation of lipohyalinosis or microatheroma in the arteries. Therefore, anti-platelet treatment might not be necessary for CSDH-inducing lacunar infarction. The lacunar infarctions caused by CSDH were small, the patients’ hemiparesis was mild, a prognosis of all the patients was good, and they recovered well from the motor weakness after physical rehabilitation. MR examinations before surgery are recommended for CSDH patients especially when a patient complains of sudden onset or rapid deterioration of motor weakness.