Treatment patterns and characteristics of headache in patients in Japan: A retrospective cross-sectional and longitudinal analysis of health insurance claims data.

BACKGROUND: The present study aimed to investigate prescription patterns for patients aged over 17 years with headaches in the REZULT database. METHODS: We conducted a cross-sectional study (Study 1) of the proportion of over-prescription of acute medications (≥30 tablets/90 days for triptans, combination non-steroidal anti-inflammatory drugs (NSAIDs) and multiple types; ≥45 tablets/90 days for single NSAIDs) among patients with headache diagnosed in 2020. We longitudinally studied (Study 2) patients for >2 years from initial headache diagnosis (July 2010 to April 2022). The number of prescribed tablets was counted every 90 days. RESULTS: In Study 1, headache was diagnosed in 200,055 of 3,638,125 (5.5%) patients: 13,651/200,055 (6.8%) received acute medication. Single NSAIDs were prescribed to 12,297/13,651 (90.1%) patients and triptans to 1710/13,651 (12.5%). Over-prescription was found in 2262/13,651 (16.6%) patients and 1200/13,651 (8.8%) patients received prophylactic medication. In Study 2, 408,183/6,840,618 (6.0%) patients were first diagnosed with headaches, which persisted for ≥2 years. Over time, the proportion of patients over-prescribed acute medications increased. Over 2 years, 37,617/408,183 (9.2%) patients were over-prescribed acute medications and 29,313/408,183 (7.2%) patients were prescribed prophylaxis at least once. CONCLUSIONS: According to real-world data, prophylaxis remains poorly prescribed, and both acute and prophylactic treatment rates for headaches have increased over time.

IL-1ß and TNF-α play an important role in modulating the risk of periodontitis and Alzheimer's disease.

BACKGROUND: Systemic activation of the immune system can exert detrimental effects on the central nervous system. Periodontitis, a chronic disease of the oral cavity, is a common source of systemic inflammation. Neuroinflammation might be a result of this to accelerate progressive deterioration of neuronal functions during aging or exacerbate pre-existing neurodegenerative diseases, such as Alzheimer's disease. With advancing age, the progressive increase in the body's pro-inflammatory status favors the state of vulnerability to both periodontitis and Alzheimer's disease. In the present study, we sought to delineate the roles of cytokines in the pathogenesis of both diseases. METHODS: To examine the impacts of periodontitis on the onset and progression of Alzheimer's disease, 6-month-old female 3 × Tg-AD mice and their age-matched non-transgenic mice were employed. Periodontitis was induced using two different experimental models: heat-killed bacterial-induced periodontitis and ligature-induced periodontitis. To delineate the roles of pro-inflammatory cytokines in the pathogenesis of periodontitis and Alzheimer's disease, interleukin 1 beta (IL-1ß) and tumor necrosis factor-alpha (TNF-α) were also injected into the buccal mandibular vestibule of mice. RESULTS: Here, we show that IL-1ß and TNF-α were two of the most important and earliest cytokines upregulated upon periodontal infection. The systemic upregulation of these two cytokines promoted a pro-inflammatory environment in the brain contributing to the development of Alzheimer's disease-like pathology and cognitive dysfunctions. Periodontitis-induced systemic inflammation also enhanced brain inflammatory responses and subsequently exacerbated Alzheimer's disease pathology and cognitive impairment in 3 × Tg-AD mice. The role of inflammation in connecting periodontitis to Alzheimer's disease was further affirmed in the conventional magnetization transfer experiment in which increased glial responses resulting from periodontitis led to decreased magnetization transfer ratios in the brain of 3 × Tg-AD mice. CONCLUSIONS: Systemic inflammation resulting from periodontitis contributed to the development of Alzheimer's disease tau pathology and subsequently led to cognitive decline in non-transgenic mice. It also potentiated Alzheimer's disease pathological features and exacerbated impairment of cognitive function in 3 × Tg-AD mice. Taken together, this study provides convincing evidence that systemic inflammation serves as a connecting link between periodontitis and Alzheimer's disease.

The efficacy of a visiting surgical service versus that of a hospital-based surgical service in providing endoscopic endonasal surgery to remove nonfunctioning pituitary adenomas in rural communities.

PURPOSE: To satisfy the increasing demand for endoscopic endonasal approach (EEA) to treat pituitary tumors, especially in rural areas, the "mobile EEA" system, a visiting surgical service, has been established We report this unique system for maintaining community healthcare and evaluate the surgical results of mobile EEA. METHODS: A retrospectively acquired database of 225 consecutive cases of EEA at Shinshu University Hospital (i.e., "home EEA") and its affiliated hospitals (i.e., "away EEA") between May 2018 and May 2022 was reviewed. A total of 105 consecutive patients who fulfilled the criterion of a diagnosis of new-onset nonfunctioning pituitary adenoma (PA) were included. Clinical characteristics and postoperative clinical outcomes were statistically compared between the home EEA and away EEA groups to assess the presence of a home advantage and/or an away disadvantage. RESULTS: Patients were stratified into two cohorts: patients treated at our hospital (home EEA: n = 41 [39.0%]) and those treated in the visiting surgical service at an affiliated hospital (away EEA: n = 64 [61.0%]). Postoperative clinical outcomes, such as the extent of tumor resection (p = 0.39), operation time (p = 0.80), visual function (p = 0.54), and occurrence of surgical complications (p = 0.53), were comparable between the groups. There were no visiting surgical service-related adverse events or accidents caused by physicians' driving to away hospitals. CONCLUSION: Pituitary surgeries performed via the mobile EEA system for nonfunctioning PAs may help maintain local community healthcare. Furthermore, this system can also contribute to the efficient training of surgeons by the same experienced pituitary surgeon using the same protocol.

Injury of the Internal Carotid Artery During Dissection of a Craniopharyngioma via the Pterional Approach: Case Report.

Among the various causes of intraoperative neurosurgical complications, a major arterial injury is one of the most devastating. Herein, the authors present a case of a 76-year-old patient who underwent removal of a craniopharyngioma via the pterional approach and experienced severe damage of her sclerotic left internal carotid artery because it was retracted excessively by a brain spatula, which resulted in complete sacrifice of the vessel. Despite stable parameters on intraoperative monitoring of motor evoked potentials and sufficient collateral blood flow, confirmed by Doppler flowmetry, a large infarct in the left cerebral hemisphere was noted after surgery. Although retraction of movable arteries, veins, and cranial nerves can often be done safely during neurosurgical procedures for effective exposure of the operative field, forced displacement of a sclerotic internal carotid artery in its paraclinoid portion anchored to the fixed distal dural ring should definitely be avoided because it poses a significant risk of major vessel damage.

Postoperative Intratumoral or Peritumoral Hematomas After Vestibular Schwannoma Resection.

BACKGROUND: Surgical removal of a vestibular schwannoma is a complex and challenging procedure, which may be complicated by development of postoperative hematomas, particularly after incomplete resection of the tumor. OBJECTIVE: To investigate the occurrence of postoperative intra- or peritumoral hematomas after surgery for a vestibular schwannoma. METHODS: This retrospective study evaluated 49 patients (age range 17-78 years) with a vestibular schwannoma, who were treated surgically via the lateral suboccipital approach between 2011 and 2016. The tumors ranged in size from 0 mm (in a case of an intracanalicular lesion) to 56 mm. In 30 cases (61%), total or near-total resection was accomplished, and in 19 cases (39%), subtotal or partial resection was done. On the basis of their bleeding tendency during tumor removal, the patients were divided into a "less-bleeding" (38 cases; 78%) and a "more-bleeding" (11 cases; 22%) subgroups. RESULTS: A maximal vestibular schwannoma diameter >30 mm, patient age >60 years, and more bleeding during tumor removal were significantly associated with incomplete (subtotal or partial) resection. In six cases (12%), serial computed tomography after surgery demonstrated a postoperative hematoma, which was caused by insufficient irrigation of the surgical field (in two cases) or resulted from peritumoral hemorrhage (in two cases), intratumoral hemorrhage (in one case), or both intra- and peritumoral hemorrhage (in one case). The latter patient required urgent reoperation. In all cases, postoperative hematomas occurred after incomplete (subtotal or partial) resection of a vestibular schwannoma, and their development was significantly associated with more bleeding during tumor removal. CONCLUSION: For avoidance of postoperative hematomas, careful hemostasis is required after completion of vestibular schwannoma removal, especially in cases with incomplete resection and an excessive bleeding tendency of the tumor tissue.

[Electrophysiological Theory for Understanding Electrical Evoked Potential Monitoring].

Intraoperative neurophysiological monitoring(IOM)is a fundamental resource for complex neurosurgical procedures to prevent unpredictable neurological deficits and identify the exact location of a neurological function. IOMs have been classified based on evoked potential measurement by electrical stimulation. To understand the mechanism of an evoked potential, we must learn how the electric current is spread in humans. In this chapter, (1)electrical stimulation via stimulation electrode, (2)nerve depolarization by electric current stimulation, and(3)electric voltage gathered by a recording electrode have been described. Some of the contents in this chapter are presented in a perspective which might differ from that of a standard electrophysiological textbook. I hope the readers find their own interpretations on how electric current is spread in humans.

Two High-Precision Proximity Capacitance CMOS Image Sensors with Large Format and High Resolution.

This paper presents newly developed two high-precision CMOS proximity capacitance image sensors: Chip A with 12 µm pitch pixels with a large detection area of 1.68 cm2; Chip B with 2.8 µm pitch 1.8 M pixels for a higher resolution. Both fabricated chips achieved a capacitance detection precision of less than 100 zF (10-19 F) at an input voltage of 20 V and less than 10 zF (10-20 F) at 300 V due to the noise cancelling technique. Furthermore, by using multiple input pulse amplitudes, a capacitance detection dynamic range of up to 123 dB was achieved. The spatial resolution improvement was confirmed by the experimentally obtained modulation transfer function for Chip B with various line and space pattens. The examples of capacitance imaging using the fabricated chips were also demonstrated.

Initial Experience with Left Transradial Neurointerventions for Cerebral Aneurysms Using the 6-French Simmons Guiding Sheath.

OBJECTIVE: The use of a transradial approach utilizing a Simmons-shaped catheter for neurointervention has been steadily increasing. Although the right radial artery is commonly used, in interventional cardiology, the left transradial approach offers clear clinical benefits for right-handed patients. To the best of our knowledge, no previous studies have examined intracranial aneurysm embolization with the routine use of the left transradial approach. The aim of this study was to evaluate the technical feasibility of left transradial intracranial aneurysm embolization. METHODS: We conducted a retrospective review of a prospective database of consecutive patients who had undergone left transradial intracranial aneurysm coiling using a 6-French Simmons guiding sheath between January and August 2021. The following outcome variables were then analyzed: whether the catheterization was successful, the angiographical results, and the presence of any procedure-related complications. RESULTS: In total, 25 patients underwent left transradial coiling for 15 anterior and 10 posterior circulation aneurysms. The Simmons guiding sheath could be successfully shaped and cannulated into the targeted vessel in all patients. All aneurysms were completely embolized without any complications. Immediate postoperative angiograms showed Raymond 1 in 10 aneurysms (40.0%), Raymond 2 in 12 (48.0%), and Raymond 3a in 3 (12.0%). None of the patients required crossover to the right radial or femoral arteries, and no radial artery spasms or occlusions were observed. CONCLUSION: The results of this study suggest that the left transradial approach for intracranial aneurysm coiling is not only safe, effective, and technically feasible, but also provides improved comfort to right-handed patients.

Tissue-resident M2 macrophages directly contact primary sensory neurons in the sensory ganglia after nerve injury.

BACKGROUND: Macrophages in the peripheral nervous system are key players in the repair of nerve tissue and the development of neuropathic pain due to peripheral nerve injury. However, there is a lack of information on the origin and morphological features of macrophages in sensory ganglia after peripheral nerve injury, unlike those in the brain and spinal cord. We analyzed the origin and morphological features of sensory ganglionic macrophages after nerve ligation or transection using wild-type mice and mice with bone-marrow cell transplants. METHODS: After protecting the head of C57BL/6J mice with lead caps, they were irradiated and transplanted with bone-marrow-derived cells from GFP transgenic mice. The infraorbital nerve of a branch of the trigeminal nerve of wild-type mice was ligated or the infraorbital nerve of GFP-positive bone-marrow-cell-transplanted mice was transected. After immunostaining the trigeminal ganglion, the structures of the ganglionic macrophages, neurons, and satellite glial cells were analyzed using two-dimensional or three-dimensional images. RESULTS: The number of damaged neurons in the trigeminal ganglion increased from day 1 after infraorbital nerve ligation. Ganglionic macrophages proliferated from days 3 to 5. Furthermore, the numbers of macrophages increased from days 3 to 15. Bone-marrow-derived macrophages increased on day 7 after the infraorbital nerve was transected in the trigeminal ganglion of GFP-positive bone-marrow-cell-transplanted mice but most of the ganglionic macrophages were composed of tissue-resident cells. On day 7 after infraorbital nerve ligation, ganglionic macrophages increased in volume, extended their processes between the neurons and satellite glial cells, and contacted these neurons. Most of the ganglionic macrophages showed an M2 phenotype when contact was observed, and little neuronal cell death occurred. CONCLUSION: Most of the macrophages that appear after a nerve injury are tissue-resident, and these make direct contact with damaged neurons that act in a tissue-protective manner in the M2 phenotype. These results imply that tissue-resident macrophages signal to neurons directly through physical contact.

Effectiveness of the intraoperative magnetic resonance imaging during endoscopic endonasal approach for acromegaly.

PURPOSE: Acromegaly is an acquired disorder usually caused by growth hormone-secreting pituitary adenoma, resolution of which requires correction of the excess hormone production. Recently, intraoperative magnetic resonance imaging (iMRI) was reported to be useful during the endoscopic endonasal approach (EEA) for pituitary adenoma. The present study was performed to quantitatively assess the role of iMRI in improving surgical outcomes in EEA for acromegaly. METHODS: Twenty surgeries for acromegaly in EEA performed at Shinshu University Hospital between April 2016 and March 2020 were reviewed retrospectively. The inclusion criteria were cases without severe cavernous sinus tumor invasion (Knosp grade 0 - 3) or history of prior pituitary surgery. Fifteen consecutive patients were enrolled in this study. Clinical characteristics and postoperative clinical outcomes were compared between patients with and without use of iMRI during EEA for acromegaly. RESULTS: Conventional navigation-guided surgery was performed in nine patients, and six underwent iMRI-guided EEA for acromegaly. Gross total resection (GTR) was obtained in the six (100%) patients in the iMRI group, and in four (44.4%) patients in the conventional group without iMRI. Postoperative clinical outcomes, including hormonal remission rate and surgical complications, were comparable between the two groups. CONCLUSION: Although iMRI significantly increased the GTR rate, we found no direct evidence of increased hormonal remission rate by use of iMRI. It is important to confirm complete tumor resection carefully with not only iMRI findings, but also with intraoperative high-definition endoscopic direct visualization to increase the hormonal remission rate of acromegaly.

Systemic inflammation linking chronic periodontitis to cognitive decline.

Persistent inflammation in the systemic immune system can impose detrimental effects on the central nervous system (CNS). Neuroinflammation might be a result of this to accelerate the progressive deterioration of neuronal functions during aging. In this regard, controlling inflammation through delaying and/or preventing chronic inflammatory diseases may be a potential strategy to prevent or modify the progression of Alzheimer's Disease (AD). Periodontitis is a chronic inflammatory disease of the oral cavity that is common among the elderly, especially for those who have decline in cognitive functions. While epidemiological findings support the association of chronic periodontitis and cognitive decline, whether they have causal relationship remains unclear. Nonetheless, the possibility that periodontopathogens, systemic immune cells and inflammatory cytokines could reach the CNS should not be overlooked. The impacts of periodontitis on CNS homeostasis and inflammation as a pathophysiological factor concerning the association between periodontitis and AD will be discussed in this review. Future work should elucidate the pathological pathways involved in periodontitis-induced cerebral infections and inflammation, and define the role of the latter in AD progression.

Long-Term Suppression of Disabling Tremor by Thalamic Stimulation in a Patient with Spinocerebellar Ataxia Type 2.

The beneficial effect of thalamic deep brain stimulation (DBS) on action tremor has been reported in a few cases of spinocerebellar ataxia (SCA); however, several factors should be taken into account regarding the indication for DBS in advanced cases. We performed DBS of the ventral intermediate nucleus (Vim) of the thalamus for treatment of coarse action tremor in a patient with SCA2 (spinocerebellar ataxia type 2) in the wheelchair-bound stage. Although improvement of the tremor of the proximal part was incomplete, the patient regained substantial parts of daily functioning. The effect lasted for more than 6 years, and the suppression of tremor significantly contributed to maintaining the level of the patient's expression into the bedridden stage. Vim DBS can be a treatment option for tremor in SCA patients, even in the advanced stage, as long as the tremor is depriving the patient of behavioral expression. As residual proximal tremor may hamper functional recovery, DBS of other targets or multi-targets should be further explored to attain a better outcome.

Pitfalls of skull base reconstruction in endoscopic endonasal approach.

Various skull base reconstruction techniques have been developed in endoscopic endonasal approach (EEA) for skull base lesions to prevent postoperative cerebrospinal fluid (CSF) leakage. This study was performed to evaluate the efficacy and pitfalls of our method of skull base reconstruction after EEA. A total of 123 patients who underwent EEA (127 surgeries) between October 2014 and May 2017 were reviewed. Our algorithm for skull base reconstruction in EEA was categorized based on intraoperative CSF leakage graded as follows: grade 0 was excluded from this study; grade 1, dural suturing with abdominal fat graft or packing of gelatin sponge into the cavity; grade 2, method for grade 1 with addition of mucosal flap or nasoseptal flap (NSF); and grade 3, duraplasty in fascia patchwork closure with NSF. Bony reconstruction was not mandatory, and there was no postoperative bed rest or initial lumbar drainage (LD) insertion in any of the cases. Postoperative CSF leakage after EEA was mostly prevented (96.3%) by our algorithm without postoperative initial LD or bed rest. On the other hand, reconstruction surgery was required for postoperative CSF leakage in two cases-one with prior multitranssphenoidal surgery and radiotherapy and another patient with poor compliance due to communication difficulties. Both of the latter patients were obese. Greater care with regard to postoperative CSF leakage is required in patients with prior EEA with radiotherapy and obesity. In such high-risk patients, initial LD or bed rest may be required to prevent postoperative CSF leakage. It is also important to restrict activities that result in increased intracranial pressure.

Histopathologic Characterization of Mifepristone-induced Ovarian Toxicity in Cynomolgus Monkeys.

Mifepristone, which is an orally active synthetic steroid with antiprogesterone activity, is known as an ovarian toxicant. Because the available data regarding the histopathologic characteristics of ovarian toxicity in nonhuman primates are limited, the present study was undertaken in order to investigate detailed histopathologic changes accompanying mifepristone-induced ovarian toxicity and its relationship to changes in menstrual cycle and circulating sex steroid hormone. Twenty mg/kg of mifepristone was orally administered daily to 4 cynomolgus monkeys for 2 months. Mifepristone inhibited the cyclic increases in circulating estradiol-17ß and progesterone levels with associated absence of menstruation. Histopathologically, the ovary in the treated animals showed follicular phase without changes in the percentage of atretic antral follicles, and reduced endometrial thickness was noted in the uterus. These changes indicated that a certain degree of antral follicle development had been retained in spite of the menstrual cycle having been arrested in mifepristone-treated animals. Our investigation suggested that it is important to perform detailed histopathologic examination of reproductive organs with precise knowledge of the characteristics of each menstrual stage to detect ovarian toxicity in nonhuman primates. Monitoring menstrual signs and circulating sex steroid hormone levels provides additional evidence for the investigation of the mechanism of ovarian toxicity.

Significance of surgical management for cystic prolactinoma.

PURPOSE: It is generally accepted that dopamine agonists (DA) represent the first-line treatment for most patients with prolactinoma, and patients become candidates for surgical intervention when DA is contraindicated. Surgical indication for cystic prolactinoma remains controversial. This study was performed to investigate the significance of surgery for cystic prolactinoma. METHODS: A total of 28 patients that underwent transsphenoidal resection of prolactinoma between February 2004 and May 2016 were reviewed. Five consecutive patients with cystic prolactinoma were included in this study. Our surgical strategy for cystic prolactinoma was categorized as follows: first, when the purpose of surgical resection was normalization of the prolactin level, aggressive resection was performed; second, when volume reduction was essential to relieve the visual symptoms and headache, internal decompression was performed followed by DA therapy. The clinical outcomes were analyzed accordingly. RESULTS: All cystic prolactinoma were resected via the transsphenoidal approach without any complications, and all symptoms including visual impairment and hypogonadal activity were finally relieved combined with medication. CONCLUSIONS: Surgery for cystic prolactinoma could be a better option. Transsphenoidal surgery is relatively safe to remove the cystic prolactinoma, additionally it can normalize the prolactine level and achieve adequate and rapid decompression of optic chiasm. The risk of transsphenoidal surgery is highly dependent on the skill of the surgeon and treatment decision for cystic prolactinoma needs to be individualized for each patient.

Endoscopic endonasal transsphenoidal surgery using the iArmS operation support robot: initial experience in 43 patients.

Objective The intelligent arm-support system, iArmS, which follows the surgeon's arm and automatically fixes it at an adequate position, was developed as an operation support robot. iArmS was designed to support the surgeon's forearm to prevent hand trembling and to alleviate fatigue during surgery with a microscope. In this study, the authors report on application of this robotic device to endoscopic endonasal transsphenoidal surgery (ETSS) and evaluate their initial experiences. Methods The study population consisted of 43 patients: 29 with pituitary adenoma, 3 with meningioma, 3 with Rathke's cleft cyst, 2 with craniopharyngioma, 2 with chordoma, and 4 with other conditions. All patients underwent surgery via the endonasal transsphenoidal approach using a rigid endoscope. During the nasal and sphenoid phases, iArmS was used to support the surgeon's nondominant arm, which held the endoscope. The details of the iArmS and clinical results were collected. Results iArmS followed the surgeon's arm movement automatically. It reduced the surgeon's fatigue and stabilized the surgeon's hand during ETSS. Shaking of the video image decreased due to the steadying of the surgeon's scope-holding hand with iArmS. There were no complications related to use of the device. Conclusions The intelligent armrest, iArmS, seems to be safe and effective during ETSS. iArmS is helpful for improving the precision and safety not only for microscopic neurosurgery, but also for ETSS. Ongoing advances in robotics ensure the continued evolution of neurosurgery.

Efficacy and safety of febuxostat for prevention of tumor lysis syndrome in patients with malignant tumors receiving chemotherapy: a phase III, randomized, multi-center trial comparing febuxostat and allopurinol.

BACKGROUND: Control of serum uric acid (sUA) levels is very important during chemotherapy in patients with malignant tumors, as the risks of tumor lysis syndrome (TLS) and renal events are increased with increasing levels of sUA. We investigated the efficacy and safety of febuxostat, a potent non-purine xanthine oxidase inhibitor, compared with allopurinol for prevention of hyperuricemia in patients with malignant tumors, including solid tumors, receiving chemotherapy in Japan. METHODS: An allopurinol-controlled multicenter, open-label, randomized, parallel-group comparative study was carried out. Patients with malignant tumors receiving chemotherapy, who had an intermediate risk of TLS or a high risk of TLS and were not scheduled to be treated with rasburicase, were enrolled and then randomized to febuxostat (60 mg/day) or allopurinol (300 or 200 mg/day). All patients started to take the study drug 24 h before chemotherapy. The primary objective was to confirm the non-inferiority of febuxostat to allopurinol based on the area under the curve (AUC) of sUA for a 6-day treatment period. RESULTS: Forty-nine and 51 patients took febuxostat and allopurinol, respectively. sUA decreased over time after initiation of study treatment. The least squares mean difference of the AUC of sUA between the treatment groups was -33.61 mg h/dL, and the 95 % confidence interval was -70.67 to 3.45, demonstrating the non-inferiority of febuxostat to allopurinol. No differences were noted in safety outcomes between the treatment groups. CONCLUSION: Febuxostat demonstrated an efficacy and safety similar to allopurinol in patients with malignant tumors receiving chemotherapy. TRIAL REGISTRY: http://www.clinicaltrials.jp ; Identifier: JapicCTI-132398.

Giant cavernous malformation in the ventrolateral midbrain with extension into the thalamus: a case report of a paramedian supracerebellar transtentorial approach.

Cavernous malformations (CMs) of the midbrain and thalamus are relatively rare and particularly difficult to be resected given their location in eloquent tissues. Here, we report a case of a 14-year-old boy who experienced repeated and progressive right hemiparesis. Image examinations showed a gradually enlarged CM originated in the left ventrolateral midbrain extending to the left thalamus with repeated hemorrhage. By performing a paramedian supracerebellar transtentorial approach, the CM was totally removed, and the patient recovered without any new neurological deficit. The authors' experience suggests that this approach is eminent in treating giant lesions involving the ventrolateral midbrain and thalamus.

Patterning of mammalian heterodont dentition within the upper and lower jaws.

Mammalian heterodont dentition is differentiated into incisors, canines, premolars, and molars in the mesial-distal direction, in both the upper and lower jaws. Although all the lower teeth are rooted in the mandible, the upper incisors are rooted in the premaxilla and the upper canine and the teeth behind it are in the maxilla. The present study uncovers ontogenetic backgrounds to these shared and differing mesiodistal patterns of the upper and lower dentition. To this end, we examined the dentition development of the house shrew, Suncus murinus, instead of the rodent model animals because the dentition of this primitive eutherian species includes all the tooth classes, and no toothless diastema region. In the shrew, the upper incisor-forming region extended over the medial nasal prominence and the mesial part of the maxillary prominence. Consequently, the maxillary and mandibular prominences were in a mirror-image relationship in terms of the mesiodistally differentiated tooth-forming regions and of the complementary gene expression pattern, with Bmp4 in the mesial and Fgf8 in the distal regions. This suggests shared molecular mechanisms regulating tooth class differentiation between the upper and lower jaws. However, the premaxillary bone appeared within the mesenchyme of the medial nasal prominence, but grew distally beyond the former epithelial boundary with the maxillary prominence to form, finally, the incisive (premaxillary-maxillary) suture just mesial to the canine. Therefore, the developmental locations of the upper incisors are not inconsistent with the classical osteological criterion of the upper canine by comparative odontologists.

Bony surface registration of navigation system in the lateral or prone position: technical note.

BACKGROUND: Navigation systems have become essential tools in neurosurgery. Precise registration is indispensable for the accuracy of navigation. The rapid and precise registration by surface matching on the facial skin is possible using the landmarks of the face in the supine position. On the other hand, incomplete registration often occurs in the lateral or prone position due to the direction of the face and displacement of the skin by headpins and obscuring of the skin by the bispectral index monitor and many electrodes on the forehead as well as the eye patch. Surface matching on the occipital scalp is not suitable for registration because the shape of the occipital scalp is flat and it is compressed in the supine position when obtaining preoperative neuroimaging. To overcome this problem, the authors have developed a new method of registration designated as "bony surface registration" in which surface matching is achieved using the bony surface of the skull after exposure. METHODS: Between June and December 2014, this technique was used in 23 patients and its effectiveness was examined. RESULTS: Registration time was markedly shortened and useful navigation was achieved due to accurate registration in all patients. CONCLUSIONS: This is the first report of a registration methodology for a navigation system in the lateral or prone position. This bony surface registration method is useful for navigation system image-guided surgery in the lateral or prone position.