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.

Hemifacial Spasm Caused by Veins Confirmed by Intraoperative Monitoring of Abnormal Muscle Response.

BACKGROUND: Hemifacial spasm (HFS) is a benign disease caused by the hyper excitement of facial nerves owing to vessel compression. The offending vessels are usually arteries, such as anterior and posterior inferior cerebellar or vertebral arteries, but there are few reports of vein involvement cases. OBJECTIVE: The aim of this study was to investigate veins as offending vessels in patients with HFS confirmed by abnormal muscle response (AMR). METHODS: We analyzed 5 patients with HFS caused by veins among 78 patients with HFS over the past 10 years. All patients underwent microvascular decompression (MVD) with AMR monitoring, whereas 3 of them underwent a second MVD. The mean follow-up time was 97 months. RESULTS: Arteries were thoroughly decompressed in 3 patients with a failed first MVD surgery who received a second surgery, during which veins at the root exit point (RExP) were decompressed with the disappearance or a significant decrease in the amplitude of AMR. Two patients showed spasm resolution after the first surgery when veins were decompressed together with the disappearance of AMR. The location of veins was RExP and the cisternal portion. All patients had excellent outcomes within 3 months, and no complications were observed. CONCLUSIONS: Veins can be offending vessels in HFS patients. AMR is useful to determine the endpoint in these cases. Once arteries are decompressed thoroughly with residual AMR, surrounding veins at unusual sites, such as the RExP or the cisternal portion, must be checked to prevent persistent HFS. Complete decompression of veins leads to a good clinical outcome.

[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.

Intraoperative and Postoperative Bleeding in Microvascular Decompression for Trigeminal Neuralgia.

OBJECTIVE: The surgical approach for the trigeminal nerve involves veins connected to the superior petrosal and tentorial sinus, and we should pay special attention to these veins. We investigated intraoperative and postoperative bleeding using our database. METHODS: A prospectively accumulated database of 247 microvascular decompression surgeries for trigeminal neuralgia over the past 10 years was analyzed. Intraoperative and postoperative bleeding was confirmed with surgical records, videos, and computed tomography. Of 235 patients, 161 were female; 85 patients were >70 years old at the time of surgery; 96 surgeries involved the left side. RESULTS: Intraoperative venous bleeding was encountered in 29 surgeries (12%): from the superior petrosal vein/sinus in 18 and the hemispheric bridging vein/tentorial sinus in 11. Massive bleeding occurred from the superior petrosal sinus owing to tear of the entrance of the superior petrosal vein in 4 surgeries and from the tentorial sinus in 3; bleeding was controlled by Surgicel with fibrin glue. Postoperative bleeding occurred in 11 surgeries (4%): intracerebellar hematoma in 2, subarachnoid hemorrhage in 3, subdural hemorrhage in 3, supratentorial subdural hemorrhage in 2, and supratentorial epidural hematoma in 1. These lesions were associated with intraoperative bleeding in 1 case, a trans-horizontal fissure approach in 1 case, coagulation of the petrosal vein in 2 cases, and unknown reasons in 7 cases. Cure without medication was achieved in 218 surgeries at an average follow-up of 4.2 years. CONCLUSIONS: Microvascular decompression for trigeminal neuralgia involves potential risks of intraoperative and postoperative bleeding.

Nonspastic hemifacial spasm confirmed by abnormal muscle responses.

BACKGROUND: Hemifacial spasm is usually diagnosed by inspection which mainly identifies involuntary movements of orbicularis oculi. Assessing abnormal muscle responses (AMR) is another diagnostic method. CASE DESCRIPTION: We report a case of left hemifacial spasm without detectable involuntary facial movements. The patient was a 48-year-old man with a long history of subjective left facial twitching. On magnetic resonance imaging (MRI), the left VIIth cranial nerve was compressed by the left anterior inferior cerebellar artery (AICA), which was in turn compressed by the left vertebral artery. We initially treated him with botulinum toxin. We were able to record AMR, and hemifacial spasm occurred after AMR stimulation, although no spasm was detectable by inspection. Subsequently, we performed microvascular decompression with transposition of the AICA that compressed the VIIth cranial nerve. His hemifacial spasm resolved by 5 weeks after surgery and was not induced by AMR stimulation. CONCLUSION: Hemifacial spasm can sometimes be diagnosed by detecting AMR rather than by visual inspection. We propose that such hemifacial spasm should be termed nonspastic hemifacial spasm.

Microvascular decompression for hypoglossal nerve palsy secondary to vertebral artery compression: A case report and review of the literature.

BACKGROUND: Neurovascular-compression syndrome (NCS) is described as a prominent pathological contact between cranial nerves and vessels. Trigeminal neuralgia, hemifacial spasm, and glossopharyngeal neuralgia are typical clinical entities associated with NCS. On the other hand, the hyoglossal nerve is rarely affected by NCS. CASE DESCRIPTION: We present a case of hypoglossal nerve palsy (HNP) secondary to vertebral artery (VA) compression. A 47-year-old man presented to our hospital with a 1-month history of dysarthria and dysphagia. Neurological examination revealed left HNP, with an intact swallowing reflex and no oropharyngeal or palatal weakness. Magnetic resonance imaging (constructive interference in steady state) revealed left hypoglossal nerve compression by the V4 segment of the left atherosclerotic VA. He underwent microvascular decompression (MVD) surgery. Intraoperatively, the VA was compressing the hypoglossal nerve. The left VA was moved and attached to the dura matter using a polytetrafluoroethylene (Teflon®) sheet and fibrin glue. Postoperatively, the patient exhibited gradual recovery of HNP in 3 months without dysfunction of lower cranial nerves. CONCLUSION: In patients with isolated HNP, vascular compression should be considered as a cause of these symptoms, and subsequent MVD can lead to resolution.

[Radiation-Induced Malignant Peripheral Nerve Sheath Tumor of the High Cervical Spine].

UNLABELLED: CASE: A 30-year-old woman presented with posterior cervical pain and left-sided omalgia. The patient had a history of non-Hodgkin's lymphoma for which she had received prophylactic whole-brain irradiation(including at the upper cervical level)17 years previously. A magnetic resonance imaging(MRI)scan obtained 1 month previously showed an intradural extramedullary mass lesion at the left C1/2 level. We initially considered the tumor to be a benign schwannoma, but the patient subsequently developed left hemiparesis and was consequently admitted 2 days after her first visit. A second MRI scan showed that the tumor had progressed markedly. Hence, the patient underwent emergency surgical excision of the tumor. However, the tumor could only be partially removed because it had strongly adhered to the ventral aspect of the spinal cord. The tumor was pathologically diagnosed as a malignant peripheral nerve sheath tumor(MPNST). The residual tumor was subjected to local irradiation and surgery, but the treatment was unsuccessful, and the patient died on the 91st day of her illness. Conclusion:We report a case of radiation-induced high cervical MPNST arising from a benign schwannoma. All 9 previously reported cases of radiation-induced spinal MPNST were reviewed. Intraspinal MPNST of the high cervical region are extremely rare and are associated with a very poor prognosis. The 5-year survival rate of such tumors is markedly worse than that of other types of MPNST, and no standard treatment has been established for this condition.

[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.

[A case of cerebral infarction treated with tissue-plasminogen activator exhibiting prolonged cerebral edema for more than 1 month].

A 62-year-old man with hypertension and diabetes mellitus controlled by medication suddenly noticed slight hemiparesis and was admitted to our hospital. Tissue-plasminogen activator (t-PA) was administered as his NIHSS was 6 and there were no contraindications. His symptoms completely resolved after t-PA injection. He was discharged on Day 9 without neurological deficits despite minor bleeding being detected in a small, low-density area in the right post-central region on CT. However, the hemiparesis gradually recurred subsequently and the low-density area had increased. He was readmitted on Day 38 due to deterioration of symptoms and enhanced CT imaging exhibited a large, low-density area in the central parasagittal region with enhancement was seen. An open biopsy was performed on Day 52 for diagnostic purposes. Histology demonstrated increased small vessels surrounded by many non-specific inflammatory cells and abundant reactive astrocytes. To date, reports of prolonged cerebral edema lasting more than 1 month after cerebral infarction are rare. This condition may be due to angiogenesis induced by t-PA. Another reason may have been the location, i.e., the parasagittal region, which is the most common area for severe cerebral edema after gamma knife surgery.

[A case of gangliocytoma: a six-year follow-up of cyst formation].

We report a case of gangliocytoma at a cortical and subcortical area in the right parietal lobe. The patient had a generalized seizure at 11 years of age. The MRI shows an ill-demarcated high intensity area in T2 weighted images including an enhancing tumor of 10 mm in diameter. At first, the tumor was carefully followed up because of its small size and the surgical risk. Three years after the onset, a cyst formed at the area of the brain edema adjacent to the tumor. The cyst gradually grew to 21 mm in diameter, the edema had disappeared, and the size of the tumor became smaller (7 mm) within the next 3 years. A mural nodule, jelly-like tumor with calcification was totally removed and diagnosed as gangliocytoma. The cyst fluid was watery-clear, its wall did not contain any tumor. This is the first report of a six-year follow-up of cyst formation of gangliocytoma supporting the concept that edema is a precursor to central nervous system peritumoral cyst formation based on the similar observation of hemangioblastomas.