[Microvascular Decompression for Trigeminal Neuralgia Caused by Trigeminocerebellar Artery].

The trigeminocerebellar artery(TCA)is a unique branch of the basilar artery. The TCA was first described in detail by Markovic et al. in 1996. The incidence of TCA was 6.9%-13.3% in previous cadaveric studies. The TCA branches from the distal part of the basilar artery, courses very close to the trigeminal nerve root entry zone, and occasionally twists or encircles the nerve root. A close relationship between the TCA and trigeminal nerve can cause trigeminal neuralgia(TN). This characteristic course of TCA requires adjuvant decompression techniques performed by the operators. In the microvascular decompression for TN caused by the TCA, operators should pay attention to the following: 1)sufficient arachnoid dissection around the TCA, 2)combined transposition and interposition technique, 3)decompression of perforators and vessels penetrating the nerve, and 4)recognition of the existence of the TCA.

Microvascular Decompression for Trigeminal Neuralgia: A Prospective, Multicenter Study.

BACKGROUND: Microvascular decompression (MVD) is the most effective procedure for the long-term management of trigeminal neuralgia (TGN). However, retrospective and single-center studies are inherently biased, and there are currently no prospective, multicenter studies. OBJECTIVE: To evaluate the short- and long-term outcomes and complications in patients with TGN who underwent MVD at specialized Japanese institutions. METHODS: We enrolled patients with TGN who underwent MVD between April 2012 and March 2015. We recorded their facial pain grade and complications at 7 d (short term), 1 yr (mid-term), and 3 yr (long term) postoperatively. RESULTS: There were 166 patients, comprising 60 men and 106 women (mean age 62.7 yr). Furthermore, 105 patients were aged over 60 yr. We conducted neuromonitoring in 84.3% of the cases. The complete pain relief, mortality, and complication rates at the short-term follow-up were 78.9%, 0%, and 16.3%, respectively. Overall, 155 patients (93.4%) completed the long-term follow-up, with the complete pain relief and complication rates of 80.0% and 5.2%, respectively. CONCLUSION: In the hands of experienced neurosurgeons, MVD for TGN can achieve high long-term curative effects. In addition, complications are uncommon and usually transient. Our results indicate that MVD is an effective and safe treatment for patients with TGN, including elderly patients.

Prospective, Multicenter Clinical Study of Microvascular Decompression for Hemifacial Spasm.

BACKGROUND: Microvascular decompression (MVD) is the most effective procedure for hemifacial spasm (HFS). MVD results from nonspecialized or low-volume institutes are not always reliable. Most studies on MVD for HFS are retrospective and single centered; to the best of our knowledge, no prospective, multicenter studies exist. OBJECTIVE: To evaluate short- and long-term outcomes and complications in patients who underwent MVD for HFS in specialized Japanese institutions, in this multicenter, prospective, cohort study. METHODS: Included patients had undergone MVD for HFS in study centers between April 2012 and March 2015. Patients' postoperative grade of involuntary movements and complications were recorded postoperatively at 7 d (short-term) and at 1 (mid-term) and 3 (long-term) yr. RESULTS: A total of 486 patients (150 men, 336 women; mean age 53.9 yr with 181 patients over 60 yr) were enrolled during the study period. Neuromonitoring was used in 96.3% of the cases. The complete cure rate of symptom relief, mortality rate, and complication rate at short-term follow-up were 70.6%, 0%, and 15%, respectively. The long-term follow-up was completed by 463 patients (95.3%); the complete cure rate of symptom relief and complication rate were 87.1% and 3.0%, respectively. CONCLUSION: Our study revealed that under expert guidance and intraoperative neuromonitoring, the long-term curative effect rate of MVD for HFS is high, while complications are uncommon and usually transient. Our results indicate that MVD is an effective and safe treatment for patients with HFS, including elderly patients.

Significance of Anomalous Anterior Inferior Cerebellar Artery-Posterior Inferior Cerebellar Artery Common Trunk Compression in Microvascular Decompression for Hemifacial Spasm.

BACKGROUND: The anterior inferior cerebellar artery-posterior inferior cerebellar artery (AICA-PICA) common trunk anomaly is reportedly one of the most common vessel variants in the posterior circulation, but reports of hemifacial spasm (HFS) associated with AICA-PICA common trunk are very rare. In the present study, we describe methods of microvascular decompression (MVD) for HFS caused by AICA-PICA common trunk compression. METHODS: Among 159 patients who underwent MVD for HFS, 16 patients had compression of the root exit zone by the AICA-PICA common trunk anomaly. The types of compression were classified into 2 groups: common trunk artery compression group and branching vessel compression group. RESULTS: The common trunk artery compression group consisted of 11 patients (69%), and the branching vessel compression group consisted of 5 patients (31%). The rostral branch (feeding the original AICA territory) coursed between the seventh and eighth cranial nerves in 5 patients, and in 13 patients (81%), the offending vessel harbored perforators around the root exit zone. Among 16 patients, 14 (87.5%) required interposition of the common trunk or the branching vessel, and in 2 patients, decompression was completed by the transposition method. Fifteen patients experienced sufficient results, and 1 had severe residual spasm. Transient facial palsy developed in 2 patients. No patients encountered recurrence. CONCLUSIONS: Reports concerning decompression methods of AICA-PICA common trunk anomaly are very rare. The tortuosity of the common trunk and perforators from the offending vessel make the usual repositioning of the offending artery much more difficult, and adequate decompression techniques are required for successful MVD.

Myocardial dysfunction identified by three-dimensional speckle tracking echocardiography in type 2 diabetes patients relates to complications of microangiopathy.

BACKGROUND: The clinical effect of diabetic microangiopathy on left ventricular (LV) function is still uncertain. The purpose of this study was to assess the relation between diabetic microvascular complications and comprehensive myocardial deformation measurements using three-dimensional (3D) speckle tracking echocardiography. METHODS: Seventy-seven asymptomatic patients with type 2 diabetes mellitus (DM) and 35 age-matched healthy control subjects underwent 3D echocardiography. Patients with coronary artery disease or LV ejection fraction <50% were excluded. Presence of proliferative retinopathy, microalbuminuria as nephropathy, and decreased coefficient of variation of R-R intervals (CVRR) <3% as cardiac autonomic neuropathy were defined as diabetic microvascular complications. RESULTS: LV ejection fraction, LV mass index, and global radial strain did not differ between control and DM patients. However, global longitudinal and circumferential strain and endocardial area change ratio were lower in patients with DM than in the controls (-12.0±3.0% vs. -16.2±1.9%, -27.7±7.1% vs. 32.2±5.7%, -37.6±7.6% vs. 44.0±6.2%, respectively, p<0.001). In DM patients, longitudinal strain is related to CVRR (R=0.58, p<0.001), retinopathy stage, and nephropathy stage. CONCLUSIONS: Diabetic microangiopathy and its accumulated effects significantly related to subclinical LV dysfunction are characterized by impaired longitudinal shortening.

Reappearance of Cranial Nerve Dysfunction Symptoms Caused by New Artery Compression More than 20 Years after Initially Successful Microvascular Decompression: Report of Two Cases.

Reappearance of symptoms of cranial nerve dysfunction is not uncommon after successful microvascular decompression (MVD). The purpose of this study was to report two quite unusual cases of recurrent and newly developed hemifacial spasm (HFS) caused by a new conflicting artery more than 20 years after the first successful surgery. In Case 1, the first MVD was performed for HFS caused by the posterior inferior cerebellar artery (PICA) when the patient was 38 years old. After 26 symptom-free years, HFS recurred on the same side of the face due to compression by the newly developed offending AICA. In Case 2, the patient was first operated on for trigeminal neuralgia by transposition of the AICA at 49 years old, but 20 symptom-free years after the first MVD, a new offending PICA compressed the facial nerve on the same side, causing HFS. These two patients underwent reoperation and gained satisfactory results postoperatively. Reappearance of symptoms related to compression of the root exit zone (REZ) by a new offending artery after such a long symptom-free interval since the first effective MVD is rare. Here, we describe two such unusual cases and discuss how to manage and prevent such reappearance of symptoms after a long time interval.

Microvascular Decompression for Hemifacial Spasm Associated with Bilateral Vertebral Artery Compression.

BACKGROUND: Microvascular decompression (MVD) has been established as an effective treatment for hemifacial spasm (HFS). However, replacement of bilateral vertebral arteries (VAs) from the root exit zone (REZ) is difficult and requires special techniques. Reports of HFS cases associated with bilateral VA compression are quite rare. This study investigated the characteristics of these arteries and methods for safe and definite decompression. METHODS: Among 131 patients who underwent MVD for HFS, 33 patients (25.2%) had associated VA compression; 4 patients (3.1%) had bilateral VA compression. Sufficient dissection of the arachnoid membrane allowed good visualization around the REZ, and the dolichoectatic VAs were successfully transposed and fixed to the nearby dura mater in 3 cases. RESULTS: The offending arteries were bilateral VAs plus the posterior inferior cerebellar artery in 2 cases, bilateral VAs plus the anterior inferior cerebellar artery-posterior inferior cerebellar artery in 1 case, and bilateral VAs in 1 case. The contralateral VA of the symptomatic side was more ectatic, dolichoectatic, and tougher than the ipsilateral VA in 3 patients and was difficult to remove. In 3 patients treated with the transposition method, complete resolution of spasm was experienced immediately after surgery. Minimal residual spasm occurred in 1 patient treated with the interposition method. Transient facial palsy developed in 1 case, and moderate hearing loss developed in another case. CONCLUSIONS: HFS caused by bilateral VA compression is rare; however, replacement of VAs from the REZ is not easy because such VAs are invariably dolichoectatic and tough. Treatment of such cases requires special techniques.

Recurrent trigeminal neuralgia at 20 years after surgery: case report.

Microvascular decompression (MVD) is now the most feasible method of treatment for trigeminal neuralgia (TN). The recurrence of symptoms is rarely encountered postoperatively. A female patient with typical right V3 distribution TN had been successfully treated by MVD at age 56 years by transposing the offending superior cerebellar artery, and she became completely pain-free postoperatively without sequelae. Twenty years after the first MVD, pain recurred on the right V2 distribution at age 76 years and she was operated on a second time to resolve the pain. Re-exploration surgery revealed that the trigeminal nerve was compressed mediocranially by the anterior inferior and posterior inferior cerebellar artery complex, which had not been close to the neural structure during the first surgery. The artery complex was successfully transpositioned to decompress the root exit zone (REZ) of the nerve and she became pain-free again. Although various causal factors likely contribute to recurrence of TN, the present case of recompression of a REZ occurred due to a newly developed offending artery which caused TN a long time after the first surgery.

Model analysis of coil embolization of cerebral aneurysms: prediction of thrombus formation in aneurysms based on the coil embolization rate.

OBJECTIVES: Intra-aneurysmal coil embolization has been established as a common method for the intravascular treatment of cerebral aneurysms, but few studies have evaluated its long-term results. Because there is no sufficient objective landmark of complete embolization, determination of its application depends on a surgeon's experience. METHODS: A glass cerebral aneurysm model was produced, and the changes in intra-aneurysmal hemodynamics were examined. Nylon thread with a diameter of 0.33 mm, resembling the coils clinically used for embolization, was used to fill in the model. After perfusion of glycerin solution to represent human blood, the half life of a dye injected into the aneurysm was optically measured, and the relationship between the half life and the volume embolization rate (VER) of nylon thread in the aneurysm was examined. RESULTS: The maximal VER obtained by filling nylon thread in the aneurysm was 41.7+/- 2.9%. The half life of the dye increased with the VER and was significantly increased at VER>30%. DISCUSSION: The half life of the dye in the aneurysm reflected stagnation of intra-aneurysmal hemodynamics, suggesting that the prolongation of the half life enhances thrombus formation. The results of this study suggested that VER>30% is sufficient for effective coil embolization.

[Traumatic internal carotid artery dissection due to compression by a helmet strap].

It is well known that wearing a helmet can reduce the risk of head injury in a traffic accident. We report a case of traumatic cervical internal carotid artery dissection due to compression by the strap of a helmet after a motorcycle accident. A 21 year-old man fell off his motorcycle and his head was struck at the right parietal region. His helmet prevented head injury, but the helmet strap which was fixed around his neck compressed his cervical internal carotid artery. He lost consciousness and developed left hemiparesis two hours after being admitted to an emergency department. Cerebral angiography revealed dissection of he right cervical internal carotid artery. This lesion was treated successfully by stent placement two months after the accident. The cause of carotid dissection was thought to be compression of his neck by the helmet strap. If the strap of a helmet is fixed around the neck, it can cause carotid artery injury during an accident, so it can be concluded that the strap of a helmet should be fixed firmly at the chin.

Trigeminal neuralgia associated with a primitive trigeminal artery variant: case report.

OBJECTIVE AND IMPORTANCE: A variant type of the primitive trigeminal artery (PTA) is a rare anomalous vessel that originates from the internal carotid artery and directly supplies the territory of the anteroinferior cerebellar artery and/or the superior cerebellar artery. We report a case of trigeminal neuralgia associated with this PTA variant, and we discuss the characteristics of this vessel. CLINICAL PRESENTATION: A 51-year-old woman presented with a 10-year history of left paroxysmal facial pain. Magnetic resonance angiography and cerebral angiography demonstrated that an aberrant vessel originating from the left internal carotid artery directly supplied the cerebellum, without a basilar artery anastomosis. INTERVENTION: Surgical exploration was performed via a left retrosigmoid approach. A loop of the aberrant vessel, which entered the posterior fossa through the isolated dural foramen, was compressing the trigeminal nerve. This aberrant vessel was displaced medially from the nerve with a prosthesis, with care to avoid kinking and avulsion of the perforating arteries. The patient's neuralgia resolved postoperatively. CONCLUSION: Although the PTA variant is frequently associated with intracranial aneurysms, it is extremely rare for the variant to lead to trigeminal neuralgia. During microvascular decompression surgery, surgeons should be careful to prevent injury of the perforating arteries arising from the PTA variant.