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via the pterional approach and experienced severe damage of her sclerotic left internal carotid artery because it was retracted excessively by a brain spatula, which resulted in complete sacrifice of the vessel.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.

Scattered cerebral infarction in the corona radiata predicts worse outcomes.

OBJECTIVES: Intracranial branch atheromatous disease often results in progressive motor deficits in the lenticulostriate arteries (LSA). In some patients with LSA infarction, magnetic resonance imaging (MRI) revealed single lesions at the LSA origin from the middle cerebral artery spreading in a scattered manner toward the distal area. This study aimed to elucidate the clinical characteristics of such cases. MATERIALS AND METHODS: This was a single-center, retrospective study comprising 1,840 consecutive patients admitted to the Ina Central Hospital, Japan. Two neurologists selected patients with LSA infarctions on the basis of MRI data. Patients with a single mass of infarct lesion from the origin were classified as the single group, whereas patients with infarct lesions as a single mass at LSA origin but divided and independent as the infarct area extended distally were classified as the scattered group. We compared the clinical characteristics and outcomes in these groups. RESULTS: The single and scattered groups included 119 and 35 patients, respectively. We defined worsening as an increase of one point or more on the National Institute of Health Stroke Scale. Univariate analysis demonstrated that patients in the scattered group showed significantly more worsening after hospitalization compared with those in the single group (48.6% vs. 28.6%; p < .05). Moreover, this can easily lead to increased disease severity (p < .016). In a multivariate analysis, group (odds ratio, 2.5 [95% CI, 1.11-5.74], p < .03) was an independent predictor of symptom worsening. CONCLUSIONS: Scattered infarction in the corona radiata is an aggravating factor leading to worse outcomes.

Visualization of thrombus using iterative reconstruction and maximum intensity projection of thin-slice CT images.

OBJECTIVE: Iterative reconstruction (IR) is a noise reduction method that facilitates the synthesis of maximum intensity projection (MIP) from a larger number of slices while maintaining resolution. The present study aimed to analyze whether CT evaluation using IR and MIP is ideal for thrombus evaluation of large vessel occlusions in patients with acute ischemic stroke. METHODS: Three types of images for each patient were reconstructed and categorized into three groups: the "conventional group," evaluated using 0.5-mm slice CT, the "MIP group," evaluated using 0.5-mm slice CT processed with MIP, and the "IR + MIP group," evaluated with 0.5-mm slice CT processed with IR and MIP. Noise and image quality were evaluated with noise standard deviation (Noise SD) and contrast-to-noise ratio (CNR). Three experts evaluated the thrombus edge coordinates, made a visual assessment, and compared the data with the digital subtraction angiography (DSA) of the mechanical thrombectomy. RESULTS: Twenty-nine patients with cerebral infarction having large vessel occlusion were included in this study. The IR + MIP group had a lower Noise SD and a statistically higher CNR, leading to more favorable image evaluations. The thrombus assessment showed no inter-rater variability in thrombus edge identification, and the visual assessment and comparison with DSA were statistically better in the IR + MIP group. CONCLUSIONS: IR reduces noise and improves resolution. MIP in combination with IR facilitates visualization of thrombus.

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.

Correlations Among Consistency, Computed Tomography Values, and Histopathological Subtypes of Spinal Meningioma.

The consistency of spinal meningiomas is important to consider when performing tumor removal surgery. This study evaluated the correlations between spinal meningioma consistency and both preoperative computed tomography (CT) values and histopathological subtypes. Fifteen consecutive patients who underwent surgical resection of spinal meningioma at our institution were identified, and preoperative CT values and the signal intensity of T2-weighted magnetic resonance images of the tumor were determined retrospectively. The consistency of the spinal meningioma was defined based on the ultrasonic surgical aspirator output during tumor debulking. Patients were assigned to 2 groups: a soft group (n=4) and a hard group (n=11). The T2 signal intensity was significantly higher in the soft group than in the hard group (p=0.001). While the CT values were considerably higher in the hard group, the difference was not significant (p=0.19). Regarding the histopathological subtypes, psammomatous meningioma exhibited significantly higher CT values than meningothelial meningioma (p=0.019); however, there was a higher frequency of hard tumors in meningothelial meningioma cases than in psammomatous meningioma cases. Although neither robust correlations between tumor consistency and CT values nor a relationship between tumor consistency and histopathological subtype has been established, these results might help with the perioperative manegement of spinal tumors.

Petroclival tension pneumocephalus: an unrivalled life threatening complication linked to molecular-targeted therapy.

A 73-year-old man with a petroclival tumor (metastatic renal cell carcinoma) presented with a progressive consciousness disturbance attributed to tension pneumocephalus during molecular-targeted therapy following low-dose fractionated radiotherapy for a petroclival tumor. The skull base defect was successfully reconstructed vi an endoscopic endonasal approach.

Appropriate surgical procedures for Chiari type 1 malformation and associated syrinx based on radiological characteristics of the craniovertebral junction.

Several surgical procedures can be applied for syrinx associated with Chiari type 1 malformation; however, it remains controversial as to which approach is the most effective. Here, we evaluated the indications and limitations of foramen magnum decompression (FMD) with or without dural plasty. Forty patients with Chiari type 1 malformation were surgically treated and followed up for > 12 months. Thirty-two patients (80.0%) underwent FMD with removal of only the outer dura mater layer, while eight patients underwent FMD with dural plasty. We evaluated surgery-related complications and preoperative radiological findings affecting syrinx shrinkage rates. Post-surgery, the mean syrinx shrinkage rates were 0.32 ± 0.44 in the outer layer-removal group and 0.72 ± 0.27 in the dural plasty group (P = 0.012). Surgery-related complications were less frequent, but reoperation was more frequent, in the outer layer-removal group. The extent of tonsillar descent significantly affected syrinx shrinkage in FMD with outer layer removal (P = 0.042). The outcomes of both approaches in patients with tonsillar descent < 10.0 mm were similar. The dura mater in the posterior fossa was thin, necessitating dural plasty with FMD, while the spinal dura was sufficiently thick for removal of the outer layer in the Chiari patients. These histological differences corresponded with the inferior margin of the cerebellar tonsil. Recognizing the appropriate surgical indication for achieving good post-procedural outcomes is necessary for reducing complications and improving outcomes of FMD for Chiari type 1 malformations.

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.

STA-ACA bypass using the ipsilateral free STA graft as an interposition graft and A3-A3 anastomosis for treatment of bilateral ACA steno-occlusive ischemia.

BACKGROUND: Anterior cerebral artery (ACA)-related ischemia is a rare entity in patients with atherosclerosis. Some surgical treatments are reported to date. METHOD: We present the modification of intracranial-intracranial and intracranial-extracranial bypasses for symptomatic bilateral ACA steno-occlusive disease. The A3-A3 bypass followed by the superficial temporal artery-ACA bypass using the ipsilateral free superficial temporal artery graft is useful without harvesting of the radial artery. CONCLUSION: Bilateral ACA steno-occlusive induced ischemia can be treated with tailored bypass procedures.

Usefulness of venous catheter as an intraluminal stent for end-to-end venous anastomosis.

BACKGROUND: Venous anastomosis is one of the most difficult techniques in vascular neurosurgery. METHOD: We present a simple technique of end-to-end venous anastomosis for reconstruction of accidentally injured vein. A venous catheter was used for the stent during the end-to-end anastomosis. RESULTS: The venous catheter as the stent facilitated confirmation of the ostium of the vein. The venous end-to-end anastomosis was successfully performed. CONCLUSIONS: Accidental venous injury can be reconstructed with the present simple technique.

Wrap-clipping as a rescue surgical technique for vessel perforation due to stent strut: a technical note.

BACKGROUND: Arterial injury related to stent strut is rare during stent-assisted coil embolization. METHOD: The patient underwent stent-assisted coil embolization for a right middle cerebral artery aneurysm. At this time, the parent arterial injury at M1 portion of the middle cerebral artery resulted in subarachnoid hemorrhage. The arterial penetration caused by the stent strut was repaired with wrap-clipping. RESULTS: Postoperative angiograms demonstrated the complete obliteration of the arterial injury. The patient was discharged without neurological deficits. Neither recurrence nor stenosis was observed after surgery. CONCLUSIONS: Wrap-clipping is a useful procedure to repair the arterial injury due to the stent strut.

Calcified ectopic TSH-secreting pituitary adenoma mimicking craniopharyngioma: a rare case report and literature review.

Among pituitary adenomas, which are relatively common brain tumors, elements of ectopic, thyroid-stimulating hormone (TSH) secretion, and intratumoral calcification are unusual. Here, we present an extremely rare case of a calcified ectopic TSH-secreting pituitary adenoma arising from the pars tuberalis mimicking craniopharyngioma based on neuroimaging findings. To our knowledge, this is the first case report of calcified ectopic TSH-secreting pituitary adenoma without symptoms of excessive thyroid hormone secretion.

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.

Transjugular tubercle-preaccessory approach for ventrocaudally located PICA aneurysm.

BACKGROUND: Posterior inferior cerebellar artery (PICA) aneurysms are often located in the ventral craniocervical junction. Such deep-seated aneurysms are usually treated with coil embolization. However, recurred and/or very small PICA aneurysms are hardly treated with an endovascular approach. METHOD: We present a modification of the transcondylar fossa approach with intradural and extradural removal of the jugular tubercle. An adequate preaccessory surgical corridor was created with this novel technique. CONCLUSION: The ventocaudal PICA aneurysm was clipped through the outside of the spinal accessory nerve without surgical manipulation of other lower cranial nerves. This approach is worthwhile to avoid dysphagia.

Clinical characteristics of pituitary adenomas with radiological calcification.

BACKGROUND: Radiographic detection of calcification in pituitary adenoma is relatively rare, and the clinical characteristics of pituitary adenoma with calcification remain unclear. Herein, the clinical characteristics of pituitary adenoma with radiological calcification were investigated. METHODS: A total of 160 patients who underwent surgical resection of pituitary adenomas between February 2004 and December 2016 were reviewed. Eighty-one patients had hormone-secreting pituitary adenomas, and 79 patients had nonfunctioning pituitary adenoma. Among these 160 patients, cases with radiological calcifications on preoperative neuroimaging were included in this study, and clinical characteristics with intraoperative findings were analyzed, retrospectively. RESULTS: Pituitary adenoma with calcification on preoperative neuroimaging was observed in only nine cases (5.6%). The study population consisted of these nine patients with nonfunctioning pituitary adenoma (n = 5), mixed growth hormone and prolactin-secreting pituitary adenomas (n = 3), and a prolactinoma (n = 1). In 89% of cases (n = 8), calcified pituitary adenoma was soft enough for suction despite the presence of a granular gritty texture intraoperatively. Besides, in a single patient (11%), evidence of hard thick capsular calcification was seen surrounding a soft tumor component; however, it did not interfere with adequate removal of the soft part, and tumor resection was possible in all cases without any complications. CONCLUSIONS: Pituitary adenoma presenting with calcification is relatively rare, but should be kept in mind to avoid making a wrong preoperative diagnosis. As not all pituitary adenomas with calcification are hard tumors, preoperative radiological calcification should not affect decision-making regarding surgical indications.

Mechanical evaluation of cerebral aneurysm clip scissoring phenomenon: comparison of titanium alloy and cobalt alloy.

Cerebral aneurysm clip blades crossing during surgery is well known as scissoring. Scissoring might cause rupture of the aneurysm due to laceration of its neck. Although aneurysm clip scissoring is well known, there have been few reports describing the details of this phenomenon. Quasi-scissoring phenomenon was introduced mechanically by rotating the clip head attached to a silicone sheet. The anti-scissoring torque during the twist of the blades was measured by changing the depth and the opening width. The closing force was also evaluated. Sugita straight clips of titanium alloy and cobalt alloy were used in the present study. In both materials, the anti-scissoring torque and the closing force were bigger 3 mm in thickness than 1 mm. The initial closing forces and the anti-scissoring torque values at each rotation angles were increased in proportion to depth. Closing forces of titanium alloy clip were slightly higher than those of cobalt alloy clip. By contrast, anti-scissoring torque values of cobalt alloy clip were bigger than those of titanium alloy clip in all conditions. In condition of 3 mm in thickness and 3 mm in depth, anti-scissoring torque vales of titanium alloy clip decreased suddenly when an angle surpassed 70 degrees. Aneurysm clip scissoring phenomenon tends to occur when clipping the aneurysm neck only with blade tips. Based on the results of this experiment, titanium alloy clip is more prone to scissoring than cobalt alloy clip under the condition that the wide blade separation distance and the shallow blade length.

A new threshold of apparent diffusion coefficient values in white matter after successful tissue plasminogen activator treatment for acute brain ischemia.

BACKGROUND AND PURPOSE: Tissue plasminogen activator (tPA) is effective for the treatment of acute brain ischemia, but may trigger fatal brain edema or hemorrhage if the brain ischemia results in a large infarct. Herein, we attempted to predict the extent of infarcts by determining the optimal threshold of ADC values on DWI that predictively distinguishes between infarct and reversible areas, and by reconstructing color-coded images based on this threshold. MATERIALS AND METHODS: The study subjects consisted of 36 patients with acute brain ischemia in whom MRA had confirmed reopening of the occluded arteries in a short time (mean: 99min) after tPA treatment. We measured the apparetnt diffusion coefficient (ADC) values in several small regions of interest over the white matter within high-intensity areas on the initial diffusion weighted image (DWI); then, by comparing the findings to the follow-up images, we obtained the optimal threshold of ADC values using receiver-operating characteristic analysis. RESULTS: The threshold obtained (583×10-6 m2/s) was lower than those previously reported; this threshold could distinguish between infarct and reversible areas with considerable accuracy (sensitivity: 0.87, specificity: 0.94). CONCLUSION: The threshold obtained and the reconstructed images were predictive of the final radiological result of tPA treatment, and this threshold may be helpful in determining the appropriate management of patients with acute brain ischemia.