Endoscopic spinal cord untethering using a 1 cm skin incision technique in pediatrics: a technical case report.

BACKGROUND: Spinal cord untethering by sectioning the filum terminale is commonly performed in tethered cord syndrome patients with minor abnormalities such as filar lipoma, thickened filum terminale, and low conus medullaris. Our endoscopic surgical technique, using the interlaminar approach, allows for sectioning the filum terminale through a very small skin incision. To our knowledge, this procedure has not been previously reported. This is the first case report involving a 1 cm skin incision. CASE PRESENTATION: A 9-month-old male patient was referred to our neurosurgical department due to a coccygeal dimple. MRI revealed a thickened fatty filum. After considering the treatment options for this patient, the parents agreed to spinal cord untethering. A midline 1 cm skin incision was made at the L4/5 vertebral level. Untethering by sectioning the filum terminale was performed by full endoscopic surgery using the interlaminar approach. The procedure was uneventful and there were no postoperative complications. CONCLUSIONS: In terms of visibility and minimizing invasiveness, our surgical technique of using the interlaminar approach with endoscopy allows for untethering by sectioning the filum terminale through a very small skin incision.

Role of RNF213 polymorphism in defining quasi-moyamoya disease and definitive moyamoya disease.

OBJECTIVE: Quasi-moyamoya disease (QMMD) is moyamoya disease (MMD) associated with additional underlying diseases. Although the ring finger protein 213 (RNF213) c.14576G>A mutation is highly correlated with MMD in the Asian population, its relationship to QMMD is unclear. Therefore, in this study the authors sought to investigate the RNF213 c.14576G>A mutation in the genetic diagnosis and classification of QMMD. METHODS: This case-control study was conducted among four core hospitals. A screening system for the RNF213 c.14576G>A mutation based on high-resolution melting curve analysis was designed. The prevalence of RNF213 c.14576G>A was investigated in 76 patients with MMD and 10 patients with QMMD. RESULTS: There were no significant differences in age, sex, family history, and mode of onset between the two groups. Underlying diseases presenting in patients with QMMD were hyperthyroidism (n = 6), neurofibromatosis type 1 (n = 2), Sjögren's syndrome (n = 1), and meningitis (n =1). The RNF213 c.14576G>A mutation was found in 64 patients (84.2%) with MMD and 8 patients (80%) with QMMD; no significant difference in mutation frequency was observed between cohorts. CONCLUSIONS: There are two forms of QMMD, one in which the vascular abnormality is associated with an underlying disease, and the other in which MMD is coincidentally complicated by an unrelated underlying disease. It has been suggested that the presence or absence of the RNF213 c.14576G>A mutation may be useful in distinguishing between these disease types.

Pathological Findings of Donor Vessels in Bypass Surgery.

(1) Background Cerebral revascularization is necessary to treat intracranial arterial stenosis caused by moyamoya disease, atherosclerosis, or large complex aneurysms. Although various donor vascular harvesting methods have been reported safe, there are no reports on the histological evaluation of donor vessels for each disease, despite the variety of diseases wherein vascular anastomosis is required. (2) Methods Pathological findings of the superficial temporal artery (STA), radial artery (RA), occipital artery (OA), and saphenous vein (SV) harvested at the institution were analyzed. Patients classified according to aneurysm, atherosclerosis, and moyamoya disease were assessed for pathological abnormalities, medical history, age, sex, smoking, and postoperative anastomosis patency. (3) Results There were 38 cases of atherosclerosis, 15 cases of moyamoya disease, and 30 cases of aneurysm in 98 donor vessels (mean age 57.2) taken after 2006. Of the 84 STA, 11 RA, 2 OA, and 1 SV arteries that were harvested, 71.4% had atherosclerosis, 11.2% had dissection, and 10.2% had inflammation. There was no significant difference in the proportion of pathological findings according to the disease. A history of hypertension is associated with atherosclerosis in donor vessels. (4) Conclusions This is the first study to histologically evaluate the pathological findings of donor vessels according to disease. The proportion of dissection findings indicative of vascular damage due to surgical manipulation was not statistically different between the different conditions.

Use of a Contest Format for Objective Assessment of Microsurgical Technique: An Observational Study.

BACKGROUND: Few studies have used simulation models to examine long-term improvement in microsurgical technique. We investigated whether improvement in surgical technique could be assessed by continuous, objective, contest-format evaluation of the same microsurgical task. METHODS: Since 2014, neurosurgeons with 1-10 years of experience participated in a biannual competition-format test. The task involved creating as many sutures as possible during the 5-minute interval after arteriotomy of a 1-mm artificial vessel. A modified version of the Objective Structured Assessment of Technical Skills examination was created and used. Changes and differences in scores over time were examined for each evaluator. RESULTS: Overall, 103 neurosurgeons participated in the study at least once, and those who participated more than once were divided into two groups: those who had the highest score in each contest and those who had the lowest score. The linear regression equations for the highest and lowest scorers were y=7.62x+81.56 (R2=0.628) and y=1.94x+67.93 (R2=0.0433), respectively. High scorers had high scores from the first time they participated, and their scores tended to increase further, while scores for low scorers tended not to increase with additional experience. Scores for the four evaluators did not significantly differ. CONCLUSIONS: Our results suggest that technical improvement in surgery can be assessed by long-term, continuous evaluation of microsurgical technique and that the present evaluation system might help increase surgical safety.

Factors Influencing Long-Term Blood Flow in Extracranial-to-Intracranial Bypass for Symptomatic Internal Carotid Artery Occlusive Disease: A Quantitative Study.

BACKGROUND: Maintaining the patency of extracranial-to-intracranial (EC-IC) bypass is critical for long-term stroke prevention. However, reports on the factors influencing long-term bypass patency and quantitative assessments of bypass patency are limited. OBJECTIVE: To quantitatively evaluate blood flow in EC-IC bypass using four-dimensional (4D) flow magnetic resonance imaging (MRI) and investigate factors influencing the long-term patency of EC-IC bypass. METHODS: Thirty-six adult Japanese patients who underwent EC-IC bypass for symptomatic internal carotid or middle cerebral artery occlusive disease were included. We examined the relationships between decreased superficial temporal artery (STA) blood flow volume and perioperative complications, long-term ischemic complications, patient background, and postoperative antithrombotic medications in patients for whom STA flow could be quantitatively assessed for at least 5 months using 4D flow MRI. RESULTS: The mean follow-up time was 54.7 ± 6.1 months. One patient presented with a stroke during the acute postoperative period that affected postoperative outcomes. No recurrent strokes were recorded during long-term follow-up. Two patients died of malignant disease. Seven cases of reduced flow occurred in the STA, which were correlated with single bypass (P = .0294) and nonuse of cilostazol (P = .0294). STA occlusion was observed in 1 patient during the follow-up period. Hypertension, age, smoking, dyslipidemia, and diabetes mellitus were not correlated with reduced blood flow in the STA. CONCLUSION: Double anastomoses and cilostazol resulted in long-term STA blood flow preservation. No recurrence of cerebral infarction was noted in either STA hypoperfusion or occlusion cases.

Cerebral Infarction Due to Occlusion of Main Trunk of Middle Cerebral Artery in Patient with Accessory Middle Cerebral Artery.

The existence of an accessory middle cerebral artery (AMCA) usually has no pathological significance. Three patients developed cerebral infarction due to thromboembolic occlusion of the main trunk of the middle cerebral artery (MCA). In these patients, AMCA originating from the anterior cerebral artery was intact, and ran to the lateral side along the main MCA. Emergency endovascular treatment to remove the thrombus in the main MCA was performed, and MCA was recanalized. In one patient, the main MCA re-occluded and cerebral infarction developed on the next day. The diameter of AMCA is commonly smaller than that of the main MCA. Therefore, volume of ischemic region depends on the collateral blood flow to the left MCA territory by AMCA. Once an anomalous MCA is detected in a patient with cerebral infarction involving the MCA territory, close examinations to assess the anatomy of both the main and anomalous MCA are mandatory.

Investigation of Objectivity in Scoring and Evaluating Microvascular Anastomosis Simulation Training.

The increase in minimally invasive surgery has led to a decrease in surgical experience. To date, there is only limited research examining whether skills are evaluated objectively and equally in simulation training, especially in microsurgery. The purpose of this study was to analyze the objectivity and equality of simulation evaluation results conducted in a contest format. A nationwide recruitment process was conducted to select study participants. Participants were recruited from a pool of qualified physicians with less than 10 years of experience. In this study, the simulation procedure consisted of incising a 1 mm thick blood vessel and suturing it with a 10-0 thread using a microscope. Initially, we planned to have the neurosurgical supervisors score the simulation procedure by direct observation. However, due to COVID-19, some study participants were unable to attend. Thus requiring some simulation procedures to be scored by video review. A total of 14 trainees participated in the study. The Cronbach's alpha coefficient among the scorers was 0.99, indicating a strong correlation. There was no statistically significant difference between the scores from the video review and direct observation judgments. There was a statistically significant difference (p <0.001) between the scores for some criteria. For the eight criteria, individual scorers assigned scores in a consistent pattern. However, this pattern differed between scorers indicating that some scorers were more lenient than others. The results indicate that both video review and direct observation methods are highly objective techniques evaluate simulation procedures.

Morphological Change of Cerebral Aneurysm with Possible Pseudoaneurysm at A2/3 of the Anterior Cerebral Artery on Three-dimensional Computed Tomographic Angiography.

Intracranial pseudoaneurysm formation due to a ruptured nontraumatic aneurysm is rare. We describe a case of ruptured aneurysm, which showed morphological change on radiological examinations. An 83-year-old woman developed subarachnoid hemorrhage (SAH) with ventricular rupture and intracerebral hematoma in the corpus callosum. Contrast-enhanced computed tomography (CE-CT) demonstrated an aneurysm at the right A2/3 junction of the anterior cerebral artery. CE-CT repeated 17 h after the initial one showed shortening of the lesion on both three-dimensional and raw images. The aneurysm was surgically clipped. In cases of SAH with a hematoma or thick SAH, there is a possibility that a pseudoaneurysm will form at the tip of the true aneurysm in an adjacent thrombus or existence of intraluminal thrombus. The morphology may change during the period between initial radiological evaluation and the operation in these cases. We should be aware that the intraoperative findings or subsequent radiological findings might be different from those observed on preoperative radiological examinations.

Risk factors for ischemic complications in vascular reconstructive surgeries.

OBJECTIVE: There have been reports on postoperative ischemic complications with vascular reconstructive surgery. However, various factors, such as lesions, operative technique, and perioperative treatment, prevent analyzing the causes of ischemic complications in vascular reconstruction surgeries. In the present study, we analyzed the cause of ischemic complications for vascular reconstruction surgeries with the same operator, surgical procedure, and perioperative treatment and without focusing on the lesions. PATIENTS AND METHODS: We retrospectively reviewed 66 patients, including 24 aneurysm cases and 42 ischemic disease cases, between 2008 and 2018. The patient group comprised 35 males and 31 females, and the patient mean age was 63.3 (23-87) years. We investigated the postoperative presence of symptomatic and asymptomatic cerebral ischemia on MRIDWI performed within 4 postoperative days. We conducted a statistical analysis of the ischemic complications and clinical and treatment factors. RESULTS: Symptomatic cerebral ischemia was detected in 3 cases, whereas asymptomatic ischemic findings were identified in 8 cases. All cases of symptomatic cerebral ischemia involved cerebral aneurysms. Results of a univariate analysis revealed an association between symptomatic cerebral ischemia and preoperative antithrombotic therapy (OR, 0.07; p =  0.049 (95 %CI; 0.007-0.8794)), clipping (OR, 4.8; p =  0.0501 (95 %CI; 1.641-342.9)), and aneurysm (OR, 14.16; p =  0.0423 (95 %CI; 0.6991-286.9)). Significant associations were found between asymptomatic cerebral ischemia and preoperative antithrombotic therapy [OR, 0.2941; p =  0.0514 (95 %CI; 0.08335-1.038)], aneurysms [OR, 7.8; p =  0.0146 (95 %CI; 1.414-43.04)] and radial artery grafts (RAGs) [OR, 6.8; p =  0.0192 (95 %CI; 1.410-32.98)]. Multivariate analysis identified clipping [OR, 5.462; p =  0.045 (95 %CI; 1.01-78.25] and preoperative antithrombotic therapy [OR, 0.187; p =  0.037 (95 %CI; 0.004-0.813)] as the risk factors for symptomatic cerebral ischemia. Further, a correlation was found between asymptomatic cerebral ischemia and RAGs [OR, 9.244; p =  0.00013 (95 %CI; 2.34-29.44)]. CONCLUSION: Ischemic complications associated with combined vascular reconstruction surgeries for cerebral aneurysms are possibly associated with procedures related to aneurysmal occlusions. Thus, vascular reconstruction surgeries can be performed relatively safely. Further, preoperative antithrombotic treatment should be considered, and caution is required for asymptomatic cerebral ischemia in RAG cases.

Hydrocephalus Secondary to Intradural Extramedullary Malignant Melanoma of Spinal Cord.

BACKGROUND: Hydrocephalus secondary to spinal cord tumors is rare. CASE DESCRIPTION: We present a 39-year-old male with gradual-onset headache whose initial diagnosis was cerebral aneurysm and communicating hydrocephalus. The correct diagnosis was primary intradural extramedullary malignant melanoma of the spinal cord. Initial brain magnetic resonance imaging demonstrated slight dilation of cerebral ventricles and a 3-mm unruptured anterior communicating artery aneurysm. He was placed under observation therapy. Two months later he was seen again due to severe headache. There was no intracranial hemorrhage on brain computed tomography scans. As we suspected rupture of the aneurysm, we operated on him for surgical clipping; however, there was no aneurysmal rupture. We found no lesions responsible for hydrocephalus, so we placed a ventriculoperitoneal shunt. His headache subsequently resolved. Nine months later he developed gait disturbance; a large volume of ascites was observed. Gadolinium-enhanced lumbar magnetic resonance imaging revealed an intradural extramedullary mass at the L-1 to S-5 level. Cytology and immunohistochemistry of the cerebrospinal fluid and ascites identified a few atypical cells positive for HMB-45, S-100 protein, and Melan-A. Whole-body examinations detected no primary lesions outside the central nervous system. Our final diagnosis was primary intradural extramedullary malignant melanoma of the spinal cord with cerebrospinal fluid dissemination. CONCLUSIONS: Our findings indicate that communicating hydrocephalus may be due to primary malignant melanoma of the spinal cord.

Second Free Flap Surgery for Skull Base Tumors: Case Report and Literature Review.

Tumors of the skull base, such as meningiomas, tend to recur. With progress in free vascularized flap surgery, an increasing number of studies are investigating skull base reconstruction with free flaps after tumor removal. In this report, we discuss the results of second free flap surgery after skull base reconstructive surgery. We retrospectively analyzed data from patients treated at our center during the period from 2013 through 2017. All four patients identified had skull base anaplastic meningioma and had undergone radiotherapy. In all cases, the flap and donor blood vessel were sourced from sites that differed from those used in the previous surgeries. No complications developed, such as cerebrospinal fluid leakage, meningitis, wound infection, wound hemorrhage, or flap necrosis. Because the first flap was found to be unviable, it was difficult to preserve and was removed. Essential points in preventing complications are anchoring at the appropriate site, pinprick testing of the created flap, and use of multilayered countermeasures to prevent cerebrospinal fluid leakage.

Optical effects on the surrounding structure during quantitative analysis using indocyanine green videoangiography: A phantom vessel study.

Various reports have been published regarding quantitative evaluations of intraoperative fluorescent intensity studies using indocyanine green (ICG) with videoangiography (VAG). The effects of scattering and point-spread functions (PSF) on quantitative ICG-VAG evaluations have not been investigated. Clinically, when ICG is administered through the peripheral vein, it reaches the tissue intra-arterially. To achieve more reliable intraoperative quantitative intensity evaluations, we examined the impact of high-intensity structures on close areas. The study was conducted using a phantom model and surgical fluorescent microscope. A region of interest (ROI) was created for the vessel model and another ROI was created within 3 cm of that. With an ROI of 6.8 mm in the vessel phantom model, 10% intensity was confirmed, even though there was no fluorescent structure. Intensity decreased gradually as the ROI moved further from the vessel model. Our study results suggest that the presence of a high-intensity structure and the size of the ROI may affect quantitative intensity evaluations using ICG-VAG. Results of linear regression analysis indicate that the relationship of intensity (Y) and distance (X) is as follows: Y(real/A) = 29 Exp(-0.062X) + 164.3 Exp(-1.81X). The optical effect should be considered when performing an intraoperative intensity study with a surgical microscope.

Reuse of a Reversed "Bone Pad" to Perforate Incompletely Penetrated Burr Holes Created by Automatic-Releasing Cranial Perforators.

BACKGROUND: It can be difficult to make complete burr holes using a perforator with automatic releasing systems in cases of a soft diploe or thick calvarial bone. OBJECTIVE: To demonstrate the utility of a flipped "bone pad" (BP) in recovery of penetration failure when using an automatic releasing perforator. METHODS: For craniotomy or ventricular drainage, the first step is to make 1 or more burr holes using a craniotome. Neurosurgeons sometimes incompletely penetrate the skull using the latest tools. As a countermeasure for such cases, we have developed a simple and practical method. When making a perforation using a high-speed perforator, a round bone piece we call the BP is formed just above the dura. We pulled the BP from a completed burr hole, and placed the reversed BP in position at the bottom of the incompletely perforated burr hole. The BP acted as a new hard surface, preventing the automatic releasing system from activating, and allowed the burr hole to be completed by the craniotome without the need for additional tools. RESULTS: With this technique, we have successfully completed 6 out of 7 imperfectly perforated burr holes using a perforator with an automatic releasing system. There were no technique-related complications, such as plunging or dural laceration. CONCLUSIONS: The method has the advantage that the BP can be obtained without drilling an additional burr hole, and can be completed without the need for increasing cost, time, or instrument usage.

New Technique for Chiasmapexy Using Iliac Crest Bone Graft: 2 Cases of Visual Impairment Caused by Empty Sella Syndrome.

BACKGROUND: Chiasmapexy is used to treat empty sella syndrome, and various materials are used for the elevation of the optic chiasm. However, the use of artificial substances may have the risk of graft infection, and fat and muscle may be absorbed over the long term after surgery. In addition, bone and cartilage may be unavailable in adequate amounts. Here, we describe a new technique for chiasmapexy using an iliac crest bone graft. CASE DESCRIPTION: The first patient was a 71-year-old woman who had undergone transsphenoidal surgery twice for the treatment of pituitary adenoma and Rathke cleft cyst. The optic chiasm collapsed after the second surgery and her visual field worsened gradually. We performed chiasmapexy using fat, fascia, and a septal mucosal flap, but the optic chiasm did not remain in the normal position because of graft shrinkage. Finally, we used an iliac crest bone graft, which resulted in good visual function. The second patient was a 58-year-old man who was incidentally diagnosed with empty sella syndrome. The patient's bitemporal hemianopia gradually progressed. As in the first case, we used an iliac crest bone graft, which halted the deterioration of visual function after chiasmapexy. CONCLUSIONS: The advantages of iliac bone are that it is less likely to absorb and become infected than synthetic materials. This method may be suitable for reoperative cases, especially those wherein the septal cartilage has been removed in a previous surgery. This method will halt visual deterioration and may be one of the considerable options for chiasmapexy operations.

Internal Carotid Artery Aneurysm Anomalously Originating from the Posterior Communicating Artery.

BACKGROUND: We report a case of an internal carotid artery (ICA) aneurysm anomalously originating from the posterior communicating artery (PComA). CASE DESCRIPTION: Preoperative radiologic findings revealed a paraclinoid carotid artery aneurysm at the level of the distal dural ring. Because of the low rupture risk, there are no treatment indications for small paraclinoid or ICA-superior hypophyseal artery unruptured aneurysms. In this case, because of the patient's age and the irregular shape of the aneurysm, treatment was considered necessary. Intraoperative findings using microscopic and endoscopic angiography showed that the aneurysm originated from the proximal branched PComA. The PComA originated from the same level as the ophthalmic artery, and the superior hypophyseal artery originated from the distal side of the PComA. CONCLUSIONS: According to numerous reports, small incidental paraclinoid aneurysms have a lower risk of rupture and growth than PComA aneurysms. Preoperative radiologic examination of unruptured small aneurysms was performed using magnetic resonance angiography and three-dimensional computed tomography angiography. Because the ability of magnetic resonance angiography and three-dimensional computed tomography angiography to detect small branches of the ICA is inferior to digital subtraction angiography, the location of an unruptured ICA aneurysm should be evaluated with other diagnostic modalities besides magnetic resonance angiography and three-dimensional computed tomography angiography.

Use of 3-dimensional computed tomography to detect a barium-masked fish bone causing esophageal perforation.

Computed tomography (CT) is useful for evaluating esophageal foreign bodies and detecting perforation. However, when evaluation is difficult owing to the previous use of barium as a contrast medium, 3-dimensional CT may facilitate accurate diagnosis. A 49-year-old man was transferred to our hospital with the diagnosis of esophageal perforation. Because barium had been used as a contrast medium for an esophagram performed at a previous hospital, horizontal CT and esophageal endoscopy could not be able to identify the foreign body or characterize the lesion. However, 3-dimensional CT clearly revealed an L-shaped foreign body and its anatomical relationships in the mediastinum. Accordingly, we removed the foreign body using an upper gastrointestinal endoscope. The foreign body was the premaxillary bone of a sea bream. The patient was discharged without complications.