Thromboembolic complications during and after embolization of unruptured aneurysms: A chronological outcome in periprocedural thromboembolic events.

Background: Ischemic complications develop after elective coil embolization procedures at a certain rate. The prevention of these events has been a longstanding issue for many interventional neuroradiologists. This study aimed to clarify whether procedural ischemic events after unruptured aneurysm embolization decrease over time with perioperative anti-thromboembolic treatment or surgical experience. Methods: This study included patients with cerebral aneurysms in our institution between July 2012 and June 2020. Dual-antiplatelet therapy (DAPT) was performed (Phase 1). Thromboembolic events developed at a certain rate; thus, rivaroxaban was administered with single-antiplatelet therapy (SAPT) to improve thromboembolic results (Phase 2), showing better outcomes than in Phase 1. Subsequently, DAPT was administered again (Phase 3). Ischemic complications were evaluated in each phase or compared between the DAPT group and the direct oral anticoagulant (DOAC) with the clopidogrel (DOAC+SAPT) group. Results: Relatively, fewer symptomatic ischemic events were noted in Phase 2 or the DOAC+SAPT group, but the outcome was not better in Phase 3 than in Phase 2. Symptomatic complications were more common in Phase 3 than in Phases 1 and 2. Conclusion: Ischemic complications occurred at a certain rate after endovascular procedures for unruptured aneurysms. The incidence did not decrease over time; particularly, standard DAPT plus postoperative anti-thromboembolic medication did not adequately decrease complications in Phase 3 compared to Phases 1 and 2. Therefore, accumulated experience or a learning curve could not explain the results. DOAC administration might decrease the risk of these events, but further accumulation of evidence or prospective investigation is warranted.

Appropriate treatment within 13 hours after onset may improve outcome in patients with high-grade aneurysmal subarachnoid hemorrhage.

OBJECTIVE: This retrospective study evaluated whether earlier timing of appropriate treatment of high-grade aneurysmal subarachnoid hemorrhage (aSAH), defined as management of ruptured intracranial aneurysm (RIA) combined with required additional surgical measures for control of increased intracranial pressure (ICP), is associated with more favorable outcomes. METHODS: The study cohort comprised 253 patients with high-grade aSAH. Modified Rankin Scale score of 0-3 at 3-month follow-up after the ictus was considered as favorable outcome. RESULTS: Appropriate treatment of aSAH was completed in 205 patients (81 %), and included clipping or coiling of RIA without (64 cases) and with (141 cases) additional surgical measures for control of increased ICP (evacuation of intracranial hematoma, decompressive craniotomy, and/or cerebrospinal fluid drainage). Favorable outcome was noted significantly more often if appropriate treatment was completed within 13 h after aSAH than between 13 and 72 h (37 % vs. 17 %; adjusted P = 0.0475), which was confirmed by evaluation in the multivariate model along with other prognostic factors. Subgroup analysis revealed that completion of the appropriate treatment within 13 h was associated with more favorable outcome in those patients, who underwent management of RIA in combination with additional surgical measures for control of increased ICP (P = 0.0023), and in those, who felt into poor outcome predicting group (P = 0.0046). CONCLUSIONS: Appropriate treatment of high-grade aSAH with management of RIA in combination with required additional surgical measures for control of increased ICP, may be associated with more favorable outcomes if completed within 13 h after the ictus.

Preoperative plasma D-dimer level may be predictive for success of cerebral reperfusion and outcome after emergency mechanical thrombectomy for intracranial large vessel occlusion.

Presented retrospective analysis evaluated whether preoperative plasma D-dimer level may predict the success of cerebral reperfusion and outcome after emergency mechanical thrombectomy (MT) for intracranial large vessel occlusion (ILVO). Study cohort comprised 121 patients (mean age, 76 ± 12 years) from two participating centers. ILVO mostly affected the M1 segment (48 cases) and internal carotid artery (ICA; 37 cases). Mean preoperative National Institutes of Health Stroke Scale (NIHSS) score was 18 ± 8. Mean preoperative plasma D-dimer level was 4.4 ± 6.6 µg/ml. In 88 patients (73%) MT resulted in successful cerebral reperfusion. Multivariate analysis revealed independent associations of non-successful cerebral reperfusion with preoperative plasma D-dimer level > 6.7 µg/ml (P = 0.0021), location of ILVO other than ICA (P = 0.0056), and prolonged antiplatelet or anticoagulant therapy before stroke onset (P = 0.0172). Plasma D-dimer level ≤ 6.7 µg/ml predicted successful cerebral reperfusion with 0.91 sensitivity and 0.36 specificity. In 39 patients (32%) treatment resulted in favorable outcome. Multivariate analysis revealed independent associations of the unfavorable outcome with non-successful cerebral reperfusion after MT (P = 0.0005), preoperative plasma D-dimer level > 1.9 µg/ml (P = 0.0131), higher preoperative NIHSS score (P = 0.0171), and chronic arterial hypertension before stroke onset (P = 0.0254). Plasma D-dimer level ≤ 1.9 µg/ml predicted favorable outcome with 0.64 sensitivity and 0.62 specificity. In conclusion, preoperative plasma D-dimer level may be predictive for success of cerebral reperfusion and outcome after emergency MT for ILVO, which may be potentially helpful for prediction of prognosis in selected treatment candidates.

Short-Vessel Occlusion Might Indicate Higher Possibility of Success in Reperfusion following Mechanical Thrombectomy in Acute Middle Cerebral Artery Occlusion.

BACKGROUND: The impact of the length of the occluded vessel in acute large-vessel occlusion on successful reperfusion by mechanical thrombectomy remains unclear. This study evaluated whether diameter and length of the occluded vessel in acute middle cerebral artery (MCA) occlusion might relate to successful reperfusion following mechanical thrombectomy. METHODS: This retrospective study included patients with acute MCA occlusion who underwent intra-aortic injection of contrast medium to obtain maximum intensity projection (MIP) images acquired by flat-panel detector computed tomography (FD-CT) equipped with an angiographic system. All patients received mechanical thrombectomy and were divided into two groups: those with successful reperfusion (Thrombolysis in Cerebral Infarction [TICI] 2b/3) and those without. We compared the diameter and length of the occluded vessel between the groups. In the sub-analysis of patients with stent retriever use, ratio of length of occluded vessel to length of the active zone was compared. RESULTS: We enrolled 29 patients (median age: 73, M1 occlusion: 51%, stent retriever use: 72%). Eighteen patients achieved TICI 2b/3 with significantly larger distal end diameter (1.7 [interquartile range: 1.5-1.9] vs. 1.2 [1.2-1.5] mm, p = 0.007) and shorter length (7.1 [4.9-9.7] vs. 12.3 [7.2-15.8] mm, p = 0.043) of the occluded vessel. Sub-analysis of 21 patients showed that the cut-off value for TICI 2b/3 reperfusion was 0.32 as the ratio between the occluded vessel and stent retriever active zone (receiver operating characteristic area under the curve: 0.90). CONCLUSION: In acute MCA occlusion, larger diameter of the distal end and shorter length of the occluded vessel on FD-CT MIP images might indicate a higher possibility of achieving TICI 2b/3 following mechanical thrombectomy.

Optimal timing and safety of the external ventricular drainage in patients with high-grade aneurysmal subarachnoid hemorrhage treated with endovascular coiling.

The presented retrospective analysis has evaluated the optimal timing and safety of external ventricular drainage (EVD) for acute hydrocephalus after aneurysmal subarachnoid hemorrhage (aSAH). The study cohort comprised 102 patients, 49 of whom underwent EVD at 3-120 h (mean, 16 h) after the clinical onset of aSAH, either before (N = 27) or after (N = 22) ruptured aneurysm coiling. Among those treated with EVD, favorable and fair outcomes at discharge (modified Rankin Scale [mRS] scores 0-3) were noted in 14 (29%) and unfavorable (mRS scores 4-6) in 35 (71%). The former was more common among women (P = 0.019) and patients without chronic arterial hypertension (P = 0.028). The cut-off value for optimal timing of EVD was defined at 13 h after the onset of aSAH. Favorable and fair outcomes were more frequent after early (≤13 h; N = 30) than late (>13 h; N = 19) EVD (40% vs. 11%; P = 0.026), whereas did not differ significantly between those in whom such procedure was done before or after ruptured aneurysm coiling (19% vs. 41%; P = 0.083). In the entire study cohort, 2 patients had re-rupture of the aneurysm, and while both of them were treated with EVD, neither case of complication was directly associated with the procedure and, in fact, preceded it. In conclusion, EVD for management of acute hydrocephalus in patients with high-grade aSAH should be preferably applied within 13 h after the clinical onset of stroke, which may be considered sufficiently safe regardless whether it is performed before or after ruptured aneurysm coiling.

Characteristics and management of the offending veins in microvascular decompression surgery for trigeminal neuralgia.

The optimal technique of microvascular decompression (MVD) for trigeminal neuralgia (TN) caused by venous conflict remains unclear. The objectives of this study are to characterize the offending veins identified during MVD for TN and to evaluate intraoperative technique applied for their management. From 2007 till 2019, 308 MVD surgeries were performed in 288 consecutive patients with TN, and in 58 of them, pure venous conflict was identified. In 44 patients, the offending vein was interrupted, as was done for small veins arising from the cisternal trigeminal nerve (CN V) or its root entry zone (REZ) causing their stretching (19 cases), small veins on the surface of REZ (9 cases), transverse pontine vein (TPV) compressing REZ or distal CN V (12 cases), and superior petrosal vein (SPV) using flow conversion technique (4 cases). In 14 other cases, the offending vein was relocated, as was done for the SPV or the vein of cerebellopontine fissure (8 cases), TPV (3 cases), and the vein of middle cerebellar peduncle (3 cases). Complete pain relief after surgery was noted in 49 patients (84%). No one patient experienced major neurological deterioration. Postoperative facial numbness developed in 14 patients (24%), and in 8 of them, it was permanent. In 14 patients, MRI demonstrated venous infarction of the middle cerebellar peduncle, which was associated with the presence of any (P = 0.0180) and permanent (P = 0.0002) facial numbness. Ten patients experienced pain recurrence. Thus, 39 patients (67%) sustained complete pain relief at the last follow-up (median, 48 months), which was significantly associated with the presence of any (P = 0.0228) and permanent (P = 0.0427) postoperative facial numbness. In conclusion, in cases of TN, small offending veins arising from REZ and/or distal CN V and causing their stretching may be coagulated and cut. In many cases, TPV can be also interrupted safely or considered as collateral way for blood outflow. The main complication of such procedures is facial numbness, which is associated with the venous infarction of middle cerebellar peduncle and long-term complete pain relief.

Successful Mechanical Thrombectomy for Subocclusive Thrombus at the Origin of Lenticulostriate Artery.

Optimal treatment of patients with intracranial subocclusive thrombus remains unclear. Such a rare case successfully managed with endovascular mechanical thrombectomy is presented. A 71-year-old man experienced a sudden onset of dysarthria and motor deficits. At the time of admission his National Institutes of Health Stroke Scale (NIHSS) score was 4. DWI demonstrated incomplete infarction within the left lenticulostriate artery (LSA) territory, MRA showed partial flow defect in the distal left M1 segment and non-visualization of the LSA, and ECG revealed atrial fibrillation, thus ischemic stroke caused by cardiogenic embolism was diagnosed. Tissue plasminogen activator was administered, but symptoms progressed and NIHSS score increased up to 8. Diagnostic angiogrpahy confirmed presence of the subocclusive thrombus within the distal left M1 segment and complete occlusion of LSA at its origin. Since conservative therapy was ineffective, mechanical thrombectomy utilizing ADAPT (a direct aspiration first-pass thrombectomy) technique was performed resulting in compete recanalization of the LSA accompanied by the prompt regress of neurological symptoms. Eventally, the patient demonstrated nearly full recovery (modified Rankin Scale score 1). Thus, mechanical thrombectomy should be considered as a reasonable option in cases of acute cerebral stroke caused by subocclusive thrombus and progressive neurological deficits despite standard conservative therapy. J. Med. Invest. 67 : 372-374, August, 2020.

Aggressive internal and external decompression as a life-saving surgery in a deeply comatose patient with fixed dilated pupils after severe traumatic brain injury: A case report.

BACKGROUND: To maximize control of the intracranial pressure in deeply comatose patients with malignant cerebral swelling, combination of the surgical techniques for internal and external brain decompression may be reasonable, as demonstrated in the presented case. CASE DESCRIPTION: A 55-year-old man was admitted with Glasgow Coma Scale (GCS) score 4, maximally dilated pupils, and absence of the pupillary light and vestibulo-ocular reflexes. Head CT revealed massive acute subdural hematoma, prominent brain shift with subfalcine and transtentorial herniation, and diffuse subarachnoid hemorrhage. Large size decompressive craniectomy and evacuation of subdural hematoma were done, however, prominent swelling of the brain and its protrusion through the bone defect remained. Therefore, extensive temporal lobectomy and removal of the bulk of temporal muscle were additionally attained followed by lax duraplasty. Gradual recovery of the patient was noted from the 1st postoperative day, and on the 70th day, his GCS score was 4T4. Three months later, his condition corresponded to the Glasgow Outcome Scale score 3 (severe disability). CONCLUSION: Aggressive internal and external decompression with combination of large size craniectomy, extensive temporal lobectomy, removal of the bulk of temporal muscle, and lax duraplasty should be considered as possible life-saving option in cases of neurosurgical emergencies with malignant cerebral swelling.

Twelve-year single critical care center experience of nicardipine prolonged-release implants in patients with subarachnoid hemorrhage: a propensity score matching analysis.

OBJECTIVE: To develop a nicardipine prolonged-release implant (NPRI) to prevent cerebral vasospasm in patients with subarachnoid hemorrhage in 1999, which may be used during craniotomy, and report the results of our recent 12-year single critical care center experience. METHODS: Of 432 patients with aneurysmal subarachnoid hemorrhage treated between 2007 and 2019, 291 were enrolled. 97 Patients were aged >70 years (33%), 194 were female (67%), 138 were World Federation of Neurological Societies grades 1, 2, and 3 (47%), 218 were Fisher group 3 (75%), and 243 had an anterior circulation aneurysm (84%). Using a propensity score matching method for these five factors, the severity of cerebral vasospasm, occurrence of delayed cerebral infarction, and modified Rankin Scale (mRS) score at discharge were analyzed. RESULTS: One hundred patients each with or without NPRI were selected, and the ratios of coil/clip were 0/100 and 88/12, respectively. Cerebral vasospasm and delayed cerebral infarction were both significantly less common in the NPRI group (p=0.004, OR=0.412 (95% CI 0.223 to 0.760) and p=0.005, OR=0.272 (95% CI 0.103 to 0.714, respectively); a significant difference was seen in the mRS score at discharge by Fisher's exact test (p=0.0025). A mRS score of 6 (dead) was less common in the group with NPRI, and mRS scores of 0 and 1 were also less common. No side effects were seen. CONCLUSIONS: NPRIs significantly reduced the occurrence of cerebral vasospasm and delayed cerebral infraction without any side effects. The NPRI and non-NPRI groups showed different patterns of short-term outcomes in the single critical care center, which might have been due to selection bias and patient characteristics. Differences in outcomes may become clear in comparisons with patients treated by craniotomy.

A Case of Hereditary Hemorrhagic Telangiectasia Suspected due to Anemia during Anticoagulation Therapy after Thrombectomy.

Objective: Hereditary hemorrhagic telangiectasia (HHT) may be associated with paradoxical cerebral embolism caused by pulmonary arteriovenous malformation (PAVM). We present a case of HHT diagnosed by progressive anemia during anticoagulant therapy following mechanical thrombectomy. Case Presentation: The patient was a 59-year-old woman who presented with acute stroke due to intracranial large vessel occlusion. Mechanical thrombectomy was successfully performed and the thrombus was retrieved. Postoperatively, anticoagulant therapy was started; however, she developed progressive anemia, which was associated with marked weakness, although no bleeding source was detected. Thorough postoperative imaging studies revealed PAVMs, which may be a source of cerebral embolism. It was noted that she frequently had episodes of epistaxis and a family history of PAVM. Embolization of PAVMs was performed to prevent the recurrence of embolic disorders. After this procedure, anticoagulant therapy was safely discontinued, which resulted in the improvement of anemia. Conclusion: Physicians need to consider the possibility of HHT associated with PAVM which can cause paradoxical cerebral embolism.

[A Case of Segmental Arterial Mediolysis:Subarachnoid Hemorrhage Followed by Abdominal Bleeding].

We describe a case involving subarachnoid and intraperitoneal hemorrhage due to segmental arterial mediolysis(SAM). A 77-year-old female patient with sudden subarachnoid hemorrhage was immediately transferred to our institution. The hemorrhage was classified as grade 2 according to the World Federation of Neurosurgical Societies system. The patient was a non-smoker and did not drink alcohol regularly. A right internal carotid aneurysm was detected using CT angiography and was clipped during frontotemporal craniotomy. Bleeding was observed from the anterior wall of the internal carotid artery, and the tear was clipped. The patient had an uneventful postoperative course until sudden cardiopulmonary arrest eight days after craniotomy. She died of massive intraperitoneal hemorrhage. Autopsy revealed that the hemorrhage was due to dissection of the celiac artery. Tunica media denaturation was observed not only in the celiac artery, but also in the splenic and internal carotid arteries, which exhibited ruptured aneurysms, and the patient was diagnosed with segmental arterial mediolysis(SAM). SAM is an arterial degenerative disease affecting the medial layer of the arterial and dissecting walls. Multiple lesions are sometimes found. Radiographic imaging findings of SAM are similar to those of dissecting aneurysms, which are characterized by a single continuous dissection of the medial layer. As observed in this case, abdominal bleeding caused by SAM can occur after intracranial bleeding. When surgeons encounter unusual intracranial dissecting aneurysms, SAM should be considered as a differential diagnosis.

Clinical Predictors of Intracranial Injuries in Infants with Minor Head Trauma.

OBJECTIVE: Minor head trauma is common in children. Although most cases are nonsignificant, minor head trauma can lead to preventable intracranial injuries. The aim of this study was to identify clinical predictors of intracranial injuries in infants with minor head trauma. METHODS: Between 2006 and 2013, we retrospectively enrolled infants <11 months old with minor head trauma. Data recorded included age, sex, cause of trauma, fall height, vomiting, bad temper, size and location of scalp hematoma, fracture, and intracranial injuries on computed tomography. RESULTS: Of 549 enrolled infants, 15 (3%) sustained traumatic intracranial injuries: epidural hematoma in 7, subarachnoid hemorrhage in 4, subdural hematoma in 3, and cerebral contusion in 1. Intracranial injuries were found in 8 of 98 infants who had fallen from a >60 cm height, 1 in 197 with fall height >30 cm, and none in 44 with fall height ≤30 cm (P = 0.0001); 1 of 2 with scalp hematomas >6 cm, 10 of 35 with hematomas >3 cm, and 2 of 121 with hematomas ≤3 cm (P = 0.0001); and 9 of 28 with temporal hematoma, 2 of 15 with parietal hematoma, 2 of 22 with occipital hematoma, and none of 98 with frontal hematoma (P = 0.0001). Logistic regression analysis showed that scalp hematoma was related to intracranial injuries (hazard ratio = 21.127, P = 0.0001), whereas age, sex, fall, vomiting, and bad temper were not. CONCLUSIONS: Fall height and size and location of scalp hematoma were associated with intracranial injuries. These factors should be considered when making decisions on radiologic examinations of infants with minor head trauma.

[Clinical features of bilateral trigeminal neuralgia].

Among 238 patients with bilateral trigeminal neuralgia(TN)who visited our hospital between April 2007 and June 2014, 5(2%)were surgically treated by microvascular decompression(MVD). The initial symptom was on the right side in four and on both sides in one patient. Intervals between the initial and second onset on the other side(left)were two months, and four, six, and eight years. None of the patients showed involvement of the first branch of the trigeminal nerve. The patients with bilateral TN were younger than the 154 patients with unilateral TN who were treated surgically by MVD in this period(45 vs. 65 years), and the bilateral TN patients predominantly were women(4/5 vs. 99/154). In the surgical field, the trigeminal nerve and root entry zone were compressed more by veins in the bi lateral TN patients than in the unilateral TN(4/5 vs. 60/154, respectively)patients. We could not identify any differences in MRI CISS before versus after the onset of left trigeminal neuralgia, suggesting that compression is not the sole cause of the symptom.

[Immediate improvement of ischemic oculopathy after stenting for internal carotid artery stenosis].

Ocular ischemic syndrome occurs when ocular circulation becomes impaired owing to various causes, leading to disturbances in the visual function. It ultimately progresses to neovascular glaucoma and loss of sight. Therefore, the early diagnosis and treatment of patients with ocular ischemic syndrome has a major effect on their visual prognosis. Herein, we describe a patient who complained of decreased vision in one eye. The patient was subsequently diagnosed with internal carotid artery stenosis because of neovascularity (rubeosis iridis) around the iris in the anterior eye. The vision of the patient improved immediately after carotid artery stenting. A review of the literature indicated that the visual improvement could be attributed to the reversal of retrograde blood flow, caused by internal carotid artery stenosis, to normal levels; the resolution of rubeosis in the anterior eye; and improvement in the visual field constriction.

[Trigeminal neuralgia caused by cerebellopontine angle lipoma:a case report and review of the literature].

A 59-year-old man presented with right trigeminal neuralgia of the second branch, which had been treated with carbamazepine. The pain could not be controlled adequately because of side effects. CT and MRI revealed a 2-cm lesion in the right cerebellopontine angle. Retrosigmoid lateral suboccipital craniectomy was performed, and a soft yellowish mass was found to be associated with the 5th, 7th, and 8th cranial nerves, anterior inferior cerebellar artery, and small vessels. The lipoma was partially resected from around the root entry zone(REZ)of the 5th nerve and small vessels were coagulated around the REZ. After surgery, there was no trigeminal neuralgia, but facial numbness and cerebellar signs were noted. Postoperative MRI showed decompression of the trigeminal nerve and venous infarction in the middle cerebellar peduncle. Reviewing similar cases, we found 19 lipoma patients presenting with trigeminal neuralgia. Symptoms of involvement of other cranial nerves were also present in 11 patients, and 14 were younger than 30 years old. Of 17 surgical cases, total resection was not attempted apart from one case. Although pain relief was achieved in all surgical cases, complications developed in 11. Surgery should be performed only in patients with disabling and uncontrolled symptoms.

[A case of acute aortic dissection presenting with cerebral ischemic symptoms: utility of 3D CT angiography and CT perfusion for the diagnosis of acute stroke].

A 76-year-old woman presented at our hospital complaining of loss of consciousness, dysarthria, and upper extremity paresis. Head CT showed no remarkable findings. 3D CT angiography (CTA) and CT perfusion (CTP) revealed acute aortic dissection (AAD) involving the innominate artery and decreased cerebral blood flow in the right cerebral hemisphere, although there were no clinical signs of AAD. The patient underwent emergency allograft replacement performed by cardiovascular surgeons. The symptoms disappeared within several days and no cerebral infarction developed. Although patients with AAD and neurological symptoms can show a fatal course when they receive tissue plasminogen activator (tPA), it is difficult to exclude patient with AAD as candidates for tPA treatment. Routine use of 3D CTA and CTP in the diagnosis of acute stroke may help overcome the above problem.

Sensitivity of CT perfusion for the diagnosis of cerebral infarction.

We aimed to determine the sensitivity of CT perfusion (CTP) for the diagnosis of cerebral infarction in the acute stage. We retrospectively reviewed patients with ischemic stroke who underwent brain CTP on arrival and MRI-diffusion weighted image (DWI) after hospitalization between October 2008 and October 2011. Final diagnosis was made from MRI-DWI findings and 87 patients were identified. Fifty-five out of 87 patients (63%) could be diagnosed with cerebral infarction by initial CTP. The sensitivity depends on the area size (s): 29% for S < 3 cm(2), 83% for S ≥ 3 cm(2) - < 6 cm(2), 88% for S ≥ 6 cm(2) - < 9 cm(2), 80% for S ≥ 9 cm(2) - < 12 cm(2), and 96% for S ≥ 12 cm(2) (p < 0.001). Sensitivity depends on the type of infarction: 0% for lacunar, 74% for atherothrombotic, and 92% for cardioembolism (p < 0.001). Sensitivity is not correlated with hours after onset. CT perfusion is an effective imaging modality for the diagnosis and treatment decisions for acute stroke, particularly more serious strokes.

[A case of cavernous sinus epidermoid: anatomical classification and surgical approach].

Epidermoid rarely appears in the cavernous sinus. We encountered a 41-year-old man with left abducens nerve palsy. A round-shaped, low-density lesion on CT was located lateral to the left cavernous sinus with a compressed and thinned lateral wall of the sphenoid sinus. We could not identify cranial nerves in the cavernous sinus, which was found to be packed with a non-enhanced, high-intensity tumor on both T1 and T2 MRI. Part of the tumor capsule and its pearly contents were removed with an intradural subtemporal approach, and an inner membranous layer with cranial nerves and a tumor capsule were seen at the bottom of the tumor cavity. Postoperatively, complete cure was achieved. Reviewing similar cases, we found 18 cavernous sinus epidermoids:extracavernous type in 5;interdural in 10;and intracavernous in 3. The interdural type could be further divided into two subtypes:superficial cavernous sinus and inner membranous types. The present case belongs to the former. Frontotemporal and subtemporal procedures via both intra- and extradural approaches are relatively safe for lesions except for the intracavernous type, because cranial nerves are not located in the lateral wall of the tumor. MRI provides more useful information on cranial nerves and aid in choosing a better treatment strategy.