The Potential Role of Preoperative Posterior Cerebral Artery Involvement in Predicting Postoperative Transient Neurological Deficits and Ischemic Stroke After Indirect Revascularization in Patients With Moyamoya Disease.

OBJECTIVE: Transient neurological deficits (TNDs) are known to develop after direct bypass for Moyamoya disease and may be risk factors for subsequent stroke. However, the factors involved in the development of TNDs and stroke after indirect revascularization alone, including their association with subsequent stroke, remain unclear. The purpose of this study was to investigate this issue. METHODS: The subjects of the study were 30 patients with Moyamoya disease who underwent a total of 40 indirect revascularization procedures at our institution. Clinical and radiological data were collected retrospectively. To examine factors associated with the development of postoperative TND/stroke/asymptomatic disease, the clinical characteristics of each group were statistically compared. RESULTS: The mean age at surgery was 7 years (range 1-63). TNDs developed after surgery in 9 out of 40 patients (22.5%). Stroke in the acute postoperative period occurred in 3 patients (7.5%), all of whom experienced cerebral infarctions. Demographic data and preoperative clinical information were not different between the groups. However, posterior cerebral artery involvement on preoperative imaging was significantly associated with the development of TNDs and stroke (P = 0.006). Furthermore, postoperative stroke was associated with unfavorable outcomes (P = 0.025). CONCLUSIONS: Posterior cerebral artery involvement is significantly associated with the occurrence of TNDs. In contrast, TNDs after indirect revascularization have little relationship with the subsequent development of stroke. TNDs usually resolve without new strokes, and a better understanding of this particular pathology could help establish an optimal treatment regimen.

Cerebellar and thalamic connector hubs facilitate the involvement of visual and cognitive networks in essential tremor.

INTRODUCTION: Connector hubs are specialized brain regions that connect multiple brain networks and therefore have the potential to affect the functions of multiple systems. This study aims to examine the involvement of connector hub regions in essential tremor. METHODS: We examined whole-brain functional connectivity alterations across multiple brain networks in 27 patients with essential tremor and 27 age- and sex-matched healthy controls to identify affected hub regions using a network metric called functional connectivity overlap ratio estimated from resting-state functional MRI. We also evaluated the relationships of affected hubs with cognitive and tremor scores in all patients and with motor function improvement scores in 15 patients who underwent postoperative follow-up evaluations after focused ultrasound thalamotomy. RESULTS: We have identified affected connector hubs in the cerebellum and thalamus. Specifically, the dentate nucleus in the cerebellum and the dorsomedial thalamus exhibited more extensive connections with the sensorimotor network in patients. Moreover, the connections of the thalamic pulvinar with the visual network were also significantly widespread in the patient group. The connections of these connector hub regions with cognitive networks were negatively associated (FDR q < 0.05) with cognitive, tremor, and motor function improvement scores. CONCLUSION: In patients with essential tremor, connector hub regions within the cerebellum and thalamus exhibited widespread functional connections with sensorimotor and visual networks, leading to alternative pathways outside the classical tremor axis. Their connections with cognitive networks also affect patients' cognitive function.

Outcomes and Prognostic Factors of Magnetic Resonance-guided Focused Ultrasound Thalamotomy for Essential Tremor at 2-year Follow-up.

Magnetic resonance-guided focused ultrasound (MRgFUS) thalamotomy is an effective treatment for essential tremor (ET). However, its long-term outcomes and prognostic factors remain unclear. This study aimed to retrospectively investigate 38 patients with ET who underwent MRgFUS thalamotomy and were followed up for >2 years. The improvement in tremor was evaluated using the Clinical Rating Scale for Tremor (CRST). Adverse events were documented, and correlations with factors, such as skull density ratio (SDR), maximum mean temperature (T-max), and lesion size, were examined. Furthermore, the outcomes were compared between two groups, one that met the cutoff values, which was previously reported (preoperative CRST-B ≤ 25, T-max ≥ 52.5°C, anterior-posterior size of lesion ≥ 3.9 mm, superior-inferior [SI] size of lesion > 5.5 mm), and the other that did not. The improvement rate was 59.4% on average at the 2-year follow-up. Adverse events, such as numbness (15.8%), dysarthria (10.5%), and lower extremity weakness (2.6%), were observed even after 2 years, although these were mild. The factors correlated with tremor improvement were the T-max and SI size of the lesion (p < 0.05), whereas the SDR showed no significance. Patients who met the aforementioned cutoff values demonstrated a 69.8% improvement at the 2-year follow-up, whereas others showed a 43.6% improvement (p < 0.05). In conclusion, MRgFUS is effective even after 2 years. The higher the T-max and the larger the lesion size, the better the tremor control. Previously reported cutoff values clearly predict the 2-year prognosis, indicating the usefulness of MRgFUS.

Characteristics of deceased subjects transported to a postmortem imaging center due to unusual death related to epilepsy.

OBJECTIVE: Patients with epilepsy have high risk of experiencing uncommon causes of death. This study aimed to evaluate patients who underwent unusual deaths related to epilepsy and identify factors that may contribute to these deaths and may also include sudden unexpected death in epilepsy (SUDEP). METHODS: We analyzed 5291 cases in which a postmortem imaging (PMI) study was performed using plane CT, because of an unexplained death. A rapid troponin T assay was performed using peripheral blood samples. Clinical information including the cause of death suspected by the attending physician, body position, place of death, medical history, and antiseizure medications was evaluated. RESULTS: A total of 132 (2.6%) patients had an obvious history of epilepsy, while 5159 individuals had no history of epilepsy (97.4%). Cerebrovascular disease was the cause of death in 1.6% of patients in the group with epilepsy, and this was significantly lower than that in the non-epilepsy group. However, drowning was significantly higher (9.1% vs. 4.4%). Unspecified cause of death was significantly more frequent in the epilepsy group (78.0% vs. 57.8%). Furthermore, the proportion of patients who demonstrated elevation of troponin T levels without prior cardiac disease was significantly higher in the epilepsy group (37.9% vs. 31.1%). At discovery of death, prone position was dominant (30.3%), with deaths occurring most commonly in the bedroom (49.2%). No antiseizure medication had been prescribed in 12% of cases, while 29.5% of patients were taking multiple antiseizure medications. SIGNIFICANCE: The prevalence of epilepsy in individuals experiencing unusual death was higher than in the general population. Despite PMI studies, no definitive cause of death was identified in a significant proportion of cases. The high troponin T levels may be explained by long intervals between death and examination or by higher incidence of myocardial damage at the time of death. PLAIN LANGUAGE SUMMARY: This study investigated unusual deaths in epilepsy patients, analyzing 5291 postmortem imaging cases. The results showed that 132 cases (2.6%) had a clear history of epilepsy. In these cases, only 22% cases were explained after postmortem examination, which is less than in non-epilepsy group (42.2%). Cerebrovascular disease was less common in the epilepsy group, while drowning was more common. Elevated troponin T levels, which suggest possibility of myocardial damage or long intervals between death and examination, were also more frequent in the epilepsy group compared to non-epilepsy group.

Efficacy of intraoperative irrigation with artificial cerebrospinal fluid in chronic subdural hematoma surgery: study protocol for a multicenter randomized controlled trial.

BACKGROUND: The surgical techniques for treatment of chronic subdural hematoma (CSDH), a common neurosurgical condition, have been discussed in a lot of clinical literature. However, the recurrence proportion after CSDH surgery remains high, ranging from 10 to 20%. The standard surgical procedure for CSDH involves a craniostomy to evacuate the hematoma, but irrigating the hematoma cavity during the procedure is debatable. The authors hypothesized that the choice of irrigation fluid might be a key factor affecting the outcomes of surgery. This multicenter randomized controlled trial aims to investigate whether intraoperative irrigation using artificial cerebrospinal fluid (ACF) followed by the placement of a subdural drain would yield superior results compared to the placement of a subdural drain alone for CSDH. METHODS: The study will be conducted across 19 neurosurgical departments in Japan. The 1186 eligible patients will be randomly allocated to two groups: irrigation using ACF or not. In either group, a subdural drain is to be placed for at least 12 h postoperatively. Similar to what was done in previous studies, we set the proportion of patients that meet the criteria for ipsilateral reoperation at 7% in the irrigation group and 12% in the non-irrigation group. The primary endpoint is the proportion of patients who meet the criteria for ipsilateral reoperation within 6 months of surgery (clinical worsening of symptoms and increased hematoma on imaging compared with the postoperative state). The secondary endpoints are the proportion of reoperations within 6 months, the proportion being stratified by preoperative hematoma architecture by computed tomography (CT) scan, neurological symptoms, patient condition, mortality at 6 months, complications associated with surgery, length of hospital stay from surgery to discharge, and time of the surgical procedure. DISCUSSION: We present the study protocol for a multicenter randomized controlled trial to investigate our hypothesis that intraoperative irrigation with ACF reduces the recurrence proportion after the removal of chronic subdural hematomas compared with no irrigation. TRIAL REGISTRATION: ClinicalTrials.gov jRCT1041220124. Registered on January 13, 2023.

Boltless nylon-suture technique for stereotactic electroencephalography as a safe, effective alternative when the anchor bolt is inappropriate.

BACKGROUND: The use of anchor bolts to secure electrodes to the skull can be difficult in some clinical situations. Herein, we present the boltless technique to secure electrodes to the scalp using nylon sutures to overcome the problems associated with anchor bolts. We investigated the safety, accuracy errors, and patient-related and operative factors affecting errors in the boltless technique. METHODS: This single-institution retrospective series analyzed 103 electrodes placed in 12 patients. The target-point localization error (TPLE), entry-point localization error (EPLE), radial error (RE), and depth error (DE) of the electrodes were calculated. RESULTS: The median of the mean operative time per electrode was 9.3 min. The median TPLE, EPLE, RE, and absolute DE value were 4.1 mm, 1.6 mm, 2.7 mm, and 1.9 mm, respectively. Positive correlations were observed between the preoperative scalp thickness, mean operative time per electrode, EPLE, RE, and the absolute value of DE versus TPLE (r = .228, p = .02; r = .678, p = .015; r = .228, p = .02; r = .445, p < .01; r = .630, p < .01, respectively), and electrode approach angle versus EPLE (r = .213, p = .031). Multivariate analysis revealed that the absolute value of DE had the strongest influence on the TPLE, followed by RE and preoperative scalp thickness, respectively (ß = .938, .544, .060, respectively, p < .001). No complications related to SEEG insertion and monitoring were encountered. CONCLUSION: The boltless technique using our unique planning and technical method is a safe, effective, and low-cost alternative in cases where anchor bolts are contraindicated.

Hemifacial spasm caused by multiple vascular attachments due to remote compression effects of a dermoid cyst in the cerebellar hemisphere: illustrative case.

BACKGROUND: Dermoid cysts located laterally in the posterior fossa are rare. The authors report the case of a dermoid cyst in the cerebellar hemisphere presenting with hemifacial spasm (HFS) caused by multiple vascular attachments due to remote compression effects. OBSERVATIONS: A 48-year-old man presented with left HFS. Computed tomography showed a mass lesion in the left cerebellar hemisphere with calcification and erosion of skull bone. Magnetic resonance imaging showed no contrast enhancement of the lesion and a dural defect. The lesion compressed the brainstem and cerebellopontine cistern, but no vascular attachments to the facial nerve were seen. Tumor removal and microvascular decompression were performed. The lesion was composed of soft tissue containing oil-like liquid and hairs, and the border of the cerebellar arachnoid was clear. There were multiple vascular attachments to the root exit zone, facial nerve, and brainstem. After displacing these arteries, the intraoperative abnormal muscle response disappeared. Histopathological findings showed stratified squamous epithelium, keratin flakes, calcifications, and hairs. The HFS disappeared completely and has remained absent for 27 months. LESSONS: The dermoid cyst originating from occipital bone compressed the cerebellar hemisphere, displacing multiple vessels and leading to HFS. Tumor removal and the removal of all vascular factors can completely resolve HFS.

Lateral Lumbar Interbody Fusion within Three-level for Patients with Neurological Symptoms due to Vertebral Fragility Fractures in the Lumbar Spine.

There is a lack of agreement on whether minimally invasive lateral lumbar intervertebral fusion (LLIF) is a suitable treatment option for vertebral fragility fractures (VFFs). Hence, we sought to evaluate the efficacy and safety of LLIF in the management of VFF with neurological deficits in the lumbar spine. Between April 2015 and March 2020, we conducted a retrospective observational study of patients with VFF treated with three-level or less LLIF. The participants had previously received conservative treatment but had not been able to control their neurological symptoms. To assess the outcomes of the LLIF procedures, the patients were followed up for a minimum of 1 year. Clinical and radiological results, which include the timing and location of the bony fusion, were analyzed. The study involved 19 patients with 23 vertebral fracture levels. The residual height of the fractured vertebra was found to be 57.0 ± 12.3% of the height of the adjacent level. The mean Japanese Orthopedic Association score significantly improved postoperatively. Postoperative radiological parameters were significantly maintained at 1 year, and lumbar lordosis was maintained at the last follow-up (45.0 ± 26.7). In total 31 LLIF levels, bone fusion was observed in four levels at 6 months postoperatively, in 16 levels at 1 year, and in 23 levels at the last follow-up. The facet joint had the highest bony fusion location. LLIF within three levels can be safely performed in certain VFF cases with sufficient residual vertebral height.

Efficacy of the latest new stimulation patterns of spinal cord stimulation for intractable neuropathic pain compared to conventional stimulation: study protocol for a clinical trial.

BACKGROUND: Spinal cord stimulation (SCS) is one of the neuromodulation therapies for chronic neuropathic pain. The conventional paresthesia-based SCS involves the application of tonic stimulation that induces a sense of paresthesia. Recently, new SCS stimulation patterns without paresthesia have been developed. Differential target multiplexed (DTM) stimulation and fast-acting subperception therapy (FAST) stimulation are the latest paresthesia-free SCS patterns. METHODS: A single-center, open-label, crossover, randomized clinical trial to investigate the superiority of SCS using the latest new stimulation patterns over conventional tonic stimulation for neuropathic pain is planned. This study consists of two steps: SCS trial (first step) and SCS system implantation (second step). In the SCS trial, participants will be randomly assigned to 4 groups receiving stimulation, including tonic, DTM, and FAST. Each stimulation will then be performed for 2 days, and a visual analog scale (VAS) for pain will be evaluated before and after each stimulation pattern. A stimulation-off period for 1 day is set between each stimulation pattern to wash out the residual previous stimulation effects. Pain improvement is defined as more than 33% reduction in the pain VAS. The primary analysis will compare pain improvement between the new stimulation patterns and the conventional tonic stimulation pattern in the SCS trial. The secondary outcomes will be evaluated as follows: (1) the relationships between causative disease and improvement rate by each stimulation pattern; (2) comparison of pain improvement between the DTM and FAST stimulation patterns in all cases and by causative disease; (3) changes in assessment items preoperatively to 24 months after the implantation; (4) preoperative factors associated with long-term effects defined as continuing for more than 12 months; and (5) adverse events related to this study 3 months after the implantation. DISCUSSION: This study aims to clarify the effectiveness of the latest new stimulation patterns compared to the conventional tonic stimulation. In addition, which stimulation pattern is most effective for which kind of causative disease will be clarified. TRIAL REGISTRATION: Japan Registry of Clinical Trials (jRCT) 1,042,220,094. Registered on 21 November 2022, and last modified on 6 January 2023. jRCT is an approved member of the Primary Registry Network of WHO ICTRP.

Sacral arteriovenous fistula with lower thoracic cord edema without perimedullary vein enlargement.

Background: Sacral dural arteriovenous fistulas (AVFs) are often undiagnosed at the initial presentation due to their rarity. Case Description: For 1 year, a 71-year-old man developed progressive motor and sensory disturbances in both legs. Magnetic resonance imaging showed spinal cord edema with mild contrast enhancement at the T9-10 and T12 levels. Although mild venous dilatation was observed only at the cauda equina level, it was not initially recognized as abnormal. Blood and cerebrospinal fluid tests and spinal angiography of the lower thoracic to upper lumbar levels were nonspecific. The patient was unsuccessfully treated with three courses of high-dose intravenous methylprednisolone. Ultimately, following repeat spinal angiography (i.e., including the bilateral internal iliac arteries) that revealed a low-flow sacral dural AVF supplied by the right lateral sacral artery, the patient underwent successful surgical venous AVF occlusion/transection. Conclusion: In cases of spinal cord edema without perimedullary abnormal flow voids, careful spinal angiography including the sacral spine is necessary even if only minimal venous dilation is initially observed at the cauda equina level.

Efficacy of Spinal Cord Stimulation Using Differential Target Multiplexed Stimulation for Intractable Pain of Hereditary Neuropathy with Liability to Pressure Palsies: A Case Report.

Hereditary neuropathy with liability to pressure palsies is an extremely rare genetic disorder; it is an autosomal dominant disorder with a high incidence of neuropathic and/or musculoskeletal pain. A case of achieving pain relief by spinal cord stimulation using differential target multiplexed stimulation for a 44-year-old female patient with hereditary neuropathy with liability to pressure palsies who was experiencing severe pain in her back, face, and all four limbs is presented. In her early teens, the initial symptoms were numbness and weakness of a limb after movement, which improved spontaneously. Transient pain in her back followed by systemic and persistent muscle weakness and pain developed. Deletion of the gene for peripheral myelin protein 22 was detected by peripheral nerve biopsy. The diagnosis of hereditary neuropathy with liability to pressure palsies was made in her early thirties. A spinal cord stimulation trial was performed because her severe pain continued despite administering many medications. Therefore, two spinal cord stimulation systems were implanted at the C3-5 and Th8-9 levels by two procedures. Pain in her back, arms, and legs decreased from 8 to 1, 5 to 1, and 6 to 2 on the numerical rating scale, respectively. Furthermore, opioid usage was tapered. The pain of hereditary neuropathy with liability to pressure palsies has a complicated pathogenesis and is resistant to pharmacological treatment. Spinal cord stimulation using differential target multiplexed stimulation may be a viable treatment option.

Direct Screw Osteosynthesis for an Elderly Osteoporotic Patient With C2 Complex Fracture.

There are various types of C2 fractures, including odontoid fractures, hangman fractures, and complex fractures, which involve the vertebral body or multiple fracture types. The published literature on C2 complex fractures is limited, and treatment strategies have not yet been established. An 80-year-old woman with a history of osteoporosis, brain stroke, and cervical spondylosis fell and sustained a C2 complex fracture. Initial treatment with a cervical collar was unsuccessful and a C2 direct screw osteosynthesis surgery was performed under an image-guided three-dimensional navigation system. The surgical procedure was successfully performed with a surgical time of 83 minutes and a blood loss of 31 ml. Her neck pain improved after surgery. Follow-up CT scans revealed acceptable healing of the fracture four months later. C2 direct screw osteosynthesis is a viable treatment option for C2 complex fractures, particularly in elderly patients who may benefit from early stabilization of the fracture to prevent complications associated with long-term conservative treatment.

Comparative Study of Surgical Outcomes of Occipitocervical and Atlantoaxial Fusion for Retro-Odontoid Pseudotumor.

OBJECTIVE: To compare the surgical and radiographic outcomes of occipitocervical fusion (OCF) with those of atlantoaxial fusion (AAF) in patients with cervical myelopathy caused by retroodontoid pseudotumors (ROPs). METHODS: This retrospective, comparative study included 26 patients; 12 underwent occipitocervical fusion (OCF) (group O) and 14 retroodontoid pseudotumor (AAF) (group A) with a minimum 2-year follow-up. Neurologic outcomes were evaluated using the Japanese Orthopedic Association (JOA) score. Radiologic assessment included the maximum anteroposterior (AP) diameter of the anteroposterior-retroodontoid pseudotumor (AP-ROP), C2-7 angle, O-C2 angle, C1-2 angle, atlantodental interval (ADI), range of motion (ROM) of the ADI, C2-C7 sagittal vertical axis (C2-7 SVA), and T1 slope. Global spinal alignments (pelvic incidence [PI] minus lumbar lordosis [LL] [PI-LL], pelvic tilt, sacral slope, and C7 sagittal vertical axis) were also compared between the groups. RESULTS: Both groups had equally good clinical outcomes with equal complication rates. Three patients had a three-level fusion, 5 cases had a four-level fusion, and 4 cases had more than five-level fusion in group O. All cases had a single-level fusion in group A. Surgical time was significantly shorter in group A. AP-ROP was significantly downsized postoperatively in both groups and was more prominent in group O. C2-7 SVA was significantly increased and C2-7A ROM was significantly reduced in group O at the final follow-up. The PI-LL showed a significant increase in group O at the final follow-up. CONCLUSIONS: Although OCF and AAF were similarly effective for cervical myelopathy with ROP, AAF was less invasive, and spinal alignment was better maintained postoperatively in AAF than OCF.

Differential target multiplexed spinal cord stimulation using a paddle-type lead placed at the appropriate site for neuropathic pain after spinal cord injury in patients with past spinal surgical histories: study protocol for an exploratory clinical trial.

BACKGROUND: Neuropathic pain after spinal cord injury (SCI), both traumatic and non-traumatic, is refractory to various treatments. Spinal cord stimulation (SCS) is one of the neuromodulation therapies for neuropathic pain, although SCS has insufficient efficacy for neuropathic pain after SCI. The reasons are presumed to be inappropriate locations of SCS leads and conventional tonic stimulation itself does not have a sufficient analgesic effect for the pain. In patients with past spinal surgical histories, the cylinder-type leads are likely to be placed on the caudal side of the SCI because of surgical adhesions. Differential target multiplexed (DTM) stimulation is one of the latest new stimulation patterns that is superior to conventional stimulation. METHODS: A single-center, open-label, randomized, two-way crossover trial is planned to investigate the efficacy of SCS using DTM stimulation placing a paddle lead at the appropriate site for neuropathic pain after SCI in patients with spinal surgical histories. The paddle-type lead delivers energy more efficiently than a cylinder-type lead. This study consists of two steps: SCS trial (first step) and SCS system implantation (second step). The primary outcome is rates of achieving pain improvement with more than 33% reduction 3 months after SCS system implantation. The secondary outcomes are to be evaluated as follows: (1) effectiveness of DTM and tonic stimulations during the SCS trial; (2) changes of assessment items from 1 to 24 months; (3) relationships between the result of the SCS trial and the effects 3 months after SCS system implantation; (4) preoperative factors associated with a long-term effect, defined as continuing for more than 12 months; and (5) whether gait function improves from 1 to 24 months. DISCUSSION: A paddle-type lead placed on the rostral side of SCI and using DTM stimulation may provide significant pain relief for patients with intractable neuropathic pain after SCI in patients with past spinal surgical histories. TRIAL REGISTRATION: Japan Registry of Clinical Trials (jRCT) jRCT 1042220093. Registered on 21 November 2022, and last modified on 6 January 2023. jRCT is approved as a member of the Primary Registry Network of WHO ICTRP.

Surgical Outcomes of Common Peroneal Nerve Entrapment Neuropathy Associated with L5 Radiculopathy.

Impingement of the common peroneal nerve, a branch of the L5 nerve root, causes common peroneal nerve entrapment neuropathy (CPNE). Although there are cases of CPNE associated with L5 radiculopathy, surgical intervention's effectiveness remains to be elucidated. This retrospective case-control study aimed to evaluate the efficacy of surgery in patients with CPNE associated with L5 radiculopathy. Twenty-two patients (25 limbs) with surgically treated CPNE between 2015 and 2022 were retrospectively reviewed. The limbs were classified into two groups: group R (limbs of CPNE associated with L5 radiculopathy) and group O (limbs of CPNE without L5 radiculopathy). The durations from onset to surgery, the nerve conduction studies (NCSs), and postoperative improvement rates for motor weakness, pain, and dysesthesia were compared between the groups. Group R included 15 limbs (13 patients), and group O included 10 limbs (9 patients). There were no significant differences in the duration from onset to surgery or abnormal findings of NCS between the two groups. The postoperative improvement rates were 88% and 100% (p = 0.62) for muscle weakness, 87% and 80% (p = 0.53) for pain, and 71% and 56% (p = 0.37) for dysesthesia in group R and group O, respectively, without significant differences between groups. CPNE associated with L5 radiculopathy is common, and the results of the present study showed that the surgical outcomes in such cases were satisfactory and comparable to those in CPNE without L5 radiculopathy.

Secondary aneurysmal bone cyst of the frontal bone with fibrous dysplasia showing rapid expansion: a case report.

A 19-year-old woman presented with swelling of the left forehead without pain. She did not have any relevant past or family history. Computed tomography showed destruction of the outer cortex of the frontal bone. A solitary mass lesion with a fluid collection was detected with magnetic resonance imaging. Because the swelling of the left forehead had enlarged rapidly with osteolytic changes, surgical removal of the lesion was performed. The lesion appeared to be enveloped in a fibrous capsule. The soft lesion was removed from the frontal bone. The outer frontal bone was absent, although the inner frontal bone was preserved. Then, the frontal bone was resected with margins from the edge of the erosion. The dura mater under the lesion was intact. A cranioplasty was performed using titanium mesh. On histological examination, the trabecular bones revealed irregular shapes and arrangements, indicating fibrous dysplasia. There was a continuous high-cell-concentration pathological lesion outside the fibrous dysplasia. There were numerous cells, such as mononuclear cells, osteoclast-like multinucleated giant cells, foam cells, and red blood cells. The osteoclast-like multinucleated giant cells and other cells did not show significant nuclear atypia. Immunostaining with H3.3G34W was negative, and the ubiquitin-specific peptidase 6/Tre-2 gene showed no rearrangements. The histopathological diagnosis was secondary aneurysmal bone cyst with fibrous dysplasia. Additional postsurgical therapy was not performed. There has been no evidence of recurrence of the lesion for two years.

Clinical Impacts of Stereotactic Electroencephalography on Epilepsy Surgery and Associated Issues in the Current Situation in Japan.

Stereotactic electroencephalography (SEEG) is receiving increasing attention as a safe and effective technique in the invasive evaluation for epileptogenic zone (EZ) detection. The main clinical question is whether the use of SEEG truly improves outcomes. Herein, we compared outcomes in our patients after three types of intracranial EEG (iEEG): SEEG, the subdural electrode (SDE), and a combined method using depth and strip electrodes. We present here our preliminary results from two demonstrative cases. Several international reports from large epilepsy centers found the following clinical advantages of SEEG: 1) three-dimensional analysis of structures, including bilateral and multilobar structures; 2) low rate of complications; 3) less pneumoencephalopathy and less patient burden during postoperative course, which allows the initiation of video-EEG monitoring immediately after implantation and does not require resection to be performed in the same hospitalization; and 4) a higher rate of good seizure control after resection. In other words, SEEG more accurately identified the EZ than the SDE method. We obtained similar results in our preliminary experiences under limited conditions. In Japan, as of August 2022, dedicated electrodes and SEEG accessories have not been approved and the use of the robot arm is not widespread. The Japanese medical community is hopeful that these issues will soon be resolved and that the experience with SEEG in Japan will align with that of large epilepsy centers internationally.

Radiographic Prediction of the Occipito-C2 Angle Variation with Changes in Distance between the Mandible and Cervical Vertebrae: A Preliminary Study.

The Occipito (O) -C2 angle reflects the correct craniocervical spine alignment; however, the poor image quality of standard intraoperative fluoroscopy at times lead to inaccurate measurements. Herein, we preliminarily investigated the relationship between the O-C2 angle and the Gonion-C2 distance, which is based on the positioning of the mandible and the cervical spine. We enrolled patients who underwent cervical spine radiography in neutral, flexion, and extension positions from January 2020 to October 2020. The difference by posture changes for each parameter was defined as the Δ value, and the Spearman's rank correlation coefficient was determined. Furthermore, we determined the cutoff value of the ΔGonion-C2 distance to predict a decrease of > 10° in the ΔO-C2 angle, which is reported to be related to dysphagia and dyspnea. Seventy-four patients were included. Spearman's rank correlations for the neutral, flexion, and extension positions were 0.630 (P < 0.001), 0.471 (P < 0.001), and 0.625 (P < 0.001), respectively, while the cutoff values of the ΔGonion-C2 distance for predicting > 10° in the ΔO-C2 angle were 9.3 mm for the neutral flexion change (sensitivity: 0.435, specificity: 0.882) and 8.3 mm for the extension-neutral change (sensitivity: 0.712, specificity: 0.909). The O-C2 angle and Gonion-C2 distances correlated; however, this correlation was weaker in the flexed position. Nevertheless, the ΔGonion-C2 distance can be used as a warning sign for postoperative complications after posterior occipital bone fusion surgery, because a decrease of > 10° in the ΔO-C2 angle can be predicted with high specificity.