[Bone drilling in microvascular decompression for trigeminal neuralgia: high morphological variety of the petrous bone].

Microvascular decompression is now a standard surgical technique for the treatment of trigeminal neuralgia. However, it is occasionally difficult to expose the trigeminal nerves because of the high anatomical variety of vascular or bony structures in the posterior fossa. We reported the case of a 59-year-old woman with trigeminal neuralgia whose site of neurovascular compression could not be observed in microvascular decompression. On approaching the trigeminal nerve, the suprameatal tubercle was so prominent that it prevented adequate visualization of the nerve tract. After drilling out the tubercle concealing the trigeminal nerve behind it, we exposed the nerve entirely and subsequently decompressed it from the superior cerebellar artery. Retrospectively, the suprameatal tubercle was found 3mm high above the posterior surface of the petrous bone. Then, we analyzed the height of suprameatal tubercles in 106 patients who underwent three-dimensional CT of the skull. Mean values of the suprameatal tubercles were 1.4-1.7mm in height, and 5.2% of them were higher than 3mm. The result suggested the high morphological variety of the petrous bone. We emphasize the importance of presurgical evaluation of the petrous bone in trigeminal neuralgia, because the neurovascular compression site may not be exposed sufficiently by the suprameatal tubercle in approximately 5% of the patients.

[Two cases of Nocardia farcinica brain abscess].

Brain abscess caused by Nocardia is a relatively rare disease, but its prognosis is poor, with the fatality being 3 times as high as that of other types of brain abscess. Nocardiosis caused by N. farcinica has higher fatality rates than nocardiosis caused by the other bacteria of the genus Nocardia. We report two cases of brain abscess caused by N. farcinica. Case 1: 72-year-old immunocompetent man. In this case, the disease healed in response to burr hole drainage and treatment with antibiotics (pazufloxacin, ciprofloxacin). Case 2: A 78-year-old woman with a history of liver cirrhosis. This patient received burr hole drainage and treatment with multiple antibiotics (sulfamethoxazole/trimethoprim, pazufloxacin, meropenem, amikacin, minocycline, and linezolid). Her brain abscess tended to alleviate but her general condition worsened, leading to death. N. farcinica is often resistant to multiple antibiotics. For treatment of brain abscess caused by this bacterium, it is essential to perform pathogen identification and a drug sensitivity test immediately, and to select optimum antibiotics, taking into account the general condition of individual patients.

A Case Report Using Goose Neck Microsnare for Severe Cervical Internal Carotid Artery Occlusion with Dolichoarteriopathy.

Objective: We report the use of a Goose Neck microsnare for cervical internal carotid artery (ICA) occlusion in a patient with dolichoarteriopathy in whom it was difficult to achieve recanalization. Case Presentation: A 65-year-old woman underwent thrombectomy for a tandem lesion of left M1 occlusion and left cervical ICA occlusion. Recanalization of left M1 occlusion was achieved. For left cervical ICA occlusion, we attempted multiple thrombectomy using an existing device, but a hard clot with mobility was caught due to dolichoarteriopathy, which made thrombectomy difficult. Using a Goose Neck microsnare, we were able to capture the thrombus and achieve recanalization. Conclusion: Thrombectomy by capturing the thrombus using a Goose Neck microsnare may be useful for capturing hard clots with mobility when it is difficult to achieve recanalization with existing devices.

An Experimental Clamping and Cutting Study of Carotid and Intracranial Stents: Preparation for Surgical Rescue in Stent Complications.

OBJECTIVE: To carry out surgery safely in vessels with stents, it is essential to have knowledge of what would happen if the stents were clamped or cut. Using all stents that are permitted in Japan, we recorded with a surgical microscope the behavior of stents when they were clamped or cut and discussed the morphologic changes along with image findings. METHODS: We classified carotid artery and intracranial stents as group 1A and 1B or group 2A and 2B according to the structure of stent eye: laser cut or blade. Each stent was clamped using a Yasargil aneurysm clip, bulldog forceps, and vascular forceps. Degree of closure and presence or absence of stent deformation after declamping were recorded using a surgical microscope. Furthermore, we performed morphologic evaluations using high-resolution cone-beam computed tomography. Lastly, each stent was cut; the behavior of the cut stent was recorded, and differences between stents were examined. RESULTS: Complete clamping was confirmed both visually and based on image evaluations with bulldog forceps and vascular forceps in the groups of carotid artery stents, with the Yasargil aneurysm clip in the intracranial stents. In the blade-type stents, we found that the stents elongated during clamping, and the component wire scattered at the time of stent cutting. Furthermore, the stents could be easily separated by holding with forceps. CONCLUSIONS: Knowing the properties of each stent is essential to conduct safe surgery in response to complications. Special care must be taken when clamping and cutting blade-type stents.

Preoperative Embolization of Meningiomas: Differences in Surgical Operability and Histopathologic Changes Between Embosphere and N-butyl 2-cyanoacrylate.

OBJECTIVE: This study aimed to examine whether there is a difference in the difficulty of extirpation after use of Embosphere versus n-butyl 2-cyanoacrylate (NBCA) for the embolization of meningiomas. METHODS: Study subjects were 20 patients with meningioma who underwent embolization using either NBCA or Embosphere from April 2012 to December 2016. The difficulty of extirpation was compared and assessed in terms of objective indices, such as operative duration, perioperative bleeding, and Simpson grade, and in terms of subjective indices such as "impression on operative field" and "hardness of tumors" that the surgeon assessed using 3-point scales (dry, moderate, bloody, and soft, moderate, hard, respectively). Pathologic findings, including ischemia, necrosis, and inflammatory changes, were assessed. RESULTS: No significant differences were found between the 2 groups regarding the mean values of operative duration (P = 0.27), perioperative bleeding (P = 0.23), and Simpson grade (P = 0.39). On the other hand, there was a significant difference with respect to the "impression on operative field" and "hardness of tumors," with reports of dry (54%; P = 0.034) and soft (81%; P = 0.0001), respectively, in the Embosphere group exceeding those of the NBCA group. The pathologic findings showed that although ischemic change (P = 0.43) and necrosis (P = 0.79) were observed in both groups, perivascular inflammation was observed only in the NBCA group (P = 0.006). CONCLUSIONS: No relative merits were found regarding objective indices, whereas the Embosphere group had superior "ease of extirpation" as reported by the surgeon.

[A case of spontaneous fusiform aneurysm in a middle cerebral artery branch which causes rapidly thrombosed formation in a short period].

A 61-year-old man presented with the complaint of headache. Investigations revealed a fusiform middle cerebral artery aneurysm at the M2 part. The formation of the aneurysm rapidly developed to a partially thrombosed aneurysm in the course of four months. As regards the treatment of the aneurysm, at first we tried surgery with a superficial temporal artery middle cerebral artery bypass (STA-MCA bypass) and trapping of the aneurysm. However, during the procedure, it was difficult to control bleeding from the temporal muscle, bone flap, and subdural space. Because of this, we finished the STA-MCA bypass without trapping of the aneurysm and then, four days later, we confirmed bypass patency and treated the aneurysm using endovascular coil embolization. Based on both surgical and interventional investigations in this case and a review of the reported literature, the authors propose that there are two mechanisms causing the middle cerebral artery fusiform aneurysm to develop thrombosed formation rapidly: (i) Peripheral middle cerebral artery branches demand less blood flow than other major trunk arteries. (ii) Bypass flow maintains perfusion to the distal branches. On the other hand, this flow alteration caused by surgical vascular bypass may promote the development of the aneurysm to thrombosed formation. The treatment of a fusiform middle cerebral artery aneurysm at the M2 part is also discussed.

Supine No-Retractor Method in Microvascular Decompression for Hemifacial Spasm: Results of 100 Consecutive Operations.

Objectives In microvascular decompression (MVD) for hemifacial spasm (HFS), the patient is placed in the lateral or park-bench position that is complicated and uncomfortable for anesthesiologists, nurses, and even the patient. Careless retraction of the cerebellum by a spatula could be the major cause of surgical complications. In our method, a patient is laid supine avoiding the complicated positioning. The subfloccular approach from a small cranial window sited on the more lateral and basal side of the occipital cranium enables the surgeon to reach all the segments of the facial nerve root without a spatula. We introduce our surgical procedures in detail along with our excellent results. Methods A total of 100 consecutive patients experiencing primary HFS were operated on with MVD by a single surgeon in our institution from August 2012 to April 2014. Results Overall, 94 patients showed the complete disappearance or a satisfactory alleviation of HFS. De novo neurologic deficits were not encountered after surgery including hearing impairment. In 47 cases, multiple offending vessels were observed in multiple possible affected sites in addition to the root entry/exit zone. Conclusions We believe this approach is superior for the safe and precise decompression of any part of the facial nerve root.

Recurrent intrasellar arachnoid cyst.

A 48-year-old man presented with complaints of decreased visual acuity persisting for 6 weeks in December 1997. Neurological examination demonstrated defects in the superior bitemporal visual field and bilateral optic atrophy. Computed tomography and magnetic resonance (MR) imaging showed an intrasellar cystic lesion. The cyst wall was excised via a transsphenoidal approach. The diagnosis was intrasellar arachnoid cyst. The sellar floor was reconstructed after packing fat in the sellar turcica. The visual complaint improved, but he was lost to follow up. Four years later, he was re-admitted complaining of decreased visual acuity. Superior bilateral field defects were found. MR imaging revealed recurrence of the intrasellar arachnoid cyst. The cyst wall was excised through a craniotomy. The visual acuity and the visual field defects gradually improved. Intrasellar arachnoid cyst may recur after transsphenoidal surgery, so long-term follow up is necessary after excision of the intrasellar cyst wall.