Endoscopic retrosigmoid trans-petrosal fissure approach for vestibular schwannomas: case series.

The management of vestibular schwannoma (VS) remains one of the most formidable challenges in neurosurgery owing to the eloquent nature of surrounding anatomy. Although endoscopy-assisted microsurgery has recently gained momentum in cerebellopontine angle region surgery, the feasibility of pure endoscopic technique has been rarely reported. Here we present the operative technique and preliminary outcomes of fully endoscopic retrosigmoid trans-petrosal fissure approach (ER-TPFA) for VS surgery. Clinical data of 36 consecutive cases of VS treated with the ER-TPFA from March 2021 to March 2023 were analyzed. The patients were placed in a modified lateral park-bench position, with the Dandy incision and suboccipital craniotomy performed. With the endoscopic holder, endoscopic procedures were performed using standard two-hand microsurgical techniques by one surgeon. Arachnoidal dissection of the petrosal fissure was performed for identifying the brainstem end of facial nerve and separating the tumor from the cerebellum, without brain retraction seen in traditional microsurgical technique. The tumors had an averaged size of 3.0 cm in diameter. According to the Hannover classification, nearly all the tumors were grade III-IV (97.3%). Using ER-TPFA, 33 patients (91.7%) achieved gross total resection. Anatomic preservation of the facial nerve was achieved in 35 cases, with 33 patients (91.7%) retaining a House-Brackmann score of 1-2 postoperatively. Four out of ten patients still had serviceable hearing 6 months after operation. Postoperatively, there was no post-craniotomy hematoma, cerebellar edema, and new-onset cerebellar ataxia. With a better visualization of the cerebellopontine angle region, ER-TPFA may help preserve facial nerve function and maintain high gross total resection rate while minimizing complications. We believe this retractorless technique can be a safe and effective alternative for the management of VS with satisfactory clinical results.

Diagnostic and management challenges in paediatric Cushing's syndrome.

OBJECTIVE: Cushing syndrome (CS) is the result of chronic exposure to glucocorticoid excess. CS in children is most often caused by the administration of exogenous steroids. Endogenous CS is rare in the paediatric population and is caused mainly by tumours of the pituitary and adrenal glands, with ectopic sources being extraordinarily rare before the age of 18 years. In addition, children and young adults with CS present with different epidemiology, management issues, prognosis and outcomes than older adult patients. This complex disorder needs early diagnosis and management to avoid the significant morbidity and even mortality that can result from chronic untreated CS. METHODS: In this review, we present the complex case of a 7-year-old boy with CS that highlights the diagnostic and management challenges of paediatric CS patients, including the considerations for genetic predisposition and life-long consequences of CS in children and young adults. RESULTS: The diagnostic protocols for the evaluation of CS have been devised for adults and tested predominantly on adults. In this review, we discuss necessary modifications so that the testing can be adjusted for use in children. Additionally, pituitary adenomas in children are generally smaller and thus more difficult to recognize on pituitary imaging. CONCLUSIONS: The management of the case and its complexities underline the need for children with CS to be managed in a centre with experienced paediatric endocrinologists and skilled neurosurgeons both for their initial diagnosis and treatment as well as for their long-term follow-up and management.

Microsurgical treatment for superior petrosal sinus dural arteriovenous fistulas.

Superior petrosal sinus (SPS) dural arteriovenous fistulas (DAVFs) are a commonly encountered type of tentorial DAVF that occasionally requires microsurgical intervention. This study aims to analyze the tributaries of the superior petrosal vein (SPV) observed intraoperatively, their association with clinical symptoms, and venous drainage patterns. This retrospective study reviewed 34 consecutive patients with SPS DAVFs who underwent microsurgical treatment at a single institution between 2014 and 2022. The cohort had a mean age of 52.8 ± 11.8 years, with 85.3% (29/34) being male. Predominant symptoms included venous hypertensive myelopathy (VHM) (55.9%) and intraparenchymal or subarachnoid hemorrhage (23.5%). Standard retrosigmoid approach was used to ligate 94.1% (32/34) of the lesions, resulting in immediate complete fistula occlusion for all patients. Supratentorial venous drainage patterns were associated with a higher incidence of intracranial hemorrhage and venous varix (P = 0.047). Infratentorial drainage patterns were more frequently linked with VHM-related symptoms (P<0.001). Patients presenting VHM-related symptoms showed a higher prevalence of drainage through the vein of the cerebellopontine fissure (VCPF) (P = 0.01), while those with intracranial hemorrhage symptoms exhibited a higher prevalence of pontotrigeminal vein (PTV) drainage (P = 0.033) in their DAVFs. Endovascular management of SPS DAVFs carries inherent risks. Surgical treatment via standard retrosigmoid craniotomy offers favorable clinical outcomes with high rates of cure. In cases featuring infratentorial venous drainage, the predominant arterialized tributary of the SPV was the VCPF, commonly associated with VHM-related symptoms. Conversely, in cases with supratentorial venous drainage, the predominant arterialized SPV tributary was the PTV, often associated with intracranial hemorrhage symptoms.

Diagnostic Accuracy of the Desmopressin Stimulation Test in the Comprehensive Assessment of ACTH-Dependent Cushing's Syndrome: A Comparative Analysis with BIPSS and TSS.

BACKGROUND: Cushing's syndrome (CS) poses diagnostic challenges, particularly in distinguishing pituitary-dependent Cushing's syndrome, Cushing's disease (CD), from the ectopic ACTH syndrome (EAS). This study evaluated the diagnostic value of the desmopressin stimulation test (DST) in patients with ACTH-dependent CS in helping this discrimination. METHODS: Twenty-three ACTH-dependent CS patients underwent sequential DST, bilateral inferior petrosal sinus sampling (BIPSS), and transsphenoidal surgery (TSS). Two definitions of a positive DST results were applied. Diagnostic performance was assessed using sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), and likelihood ratios. To avoid bias from predetermined criteria, we generated univariate receiver-operating characteristic (ROC) curves, plotting sensitivity against 1-specificity at various percentage cortisol and ACTH response levels. RESULTS: Against BIPSS, DST demonstrated robust sensitivity (Definition 1: 90.0%, Definition 2: 76.2%) and overall accuracy (Definition 1: 87.0%, Definition 2: 73.9%). PPV was high (Definition 1: 95.0%, Definition 2: 94.1%), but NPV indicated potential false negatives. Compared to TSS, DST showed good sensitivity (Definition 1: 90.9-77.3%) and PPV (100.0%) but limited NPV (16.7%). The likelihood ratios emphasized the diagnostic value of the test. Notably, against TSS, DST showed perfect discriminatory power (AUC 1.000 for percent ACTH, 0.983 for percent cortisol). CONCLUSION: The desmopressin test shows promise in accurately identifying the underlying cause of ACTH-dependent CS, potentially reducing the reliance on invasive procedures and providing a practical solution for managing complex cases. Further research with larger cohorts is required to validate the utility of the DST in routine clinical practice.

The intrabulbar or extrabulbar growth pattern and its surgical outcomes of jugular foramen paragangliomas.

OBJECTIVE: This study is to define a subclassification system of jugular foramen paragangliomas (JFPs) and to demonstrate corresponding microsurgical outcomes of JFPs. STUDY DESIGN: Retrospective study. SETTING: A single-center study. METHODS: We conducted a retrospective review of the clinical data of 44 patients with JFPs who underwent surgical management. Extrabulbar(Be) tumor and intrabulbar(Bi) tumor are defined based on the growth patterns, receiver operating characteristic (ROC) curves of the imaging profile were generated and was confirmed based on intraoperative findings. Area Under Curve (AUC), accuracy, sensitivity, and specificity for diagnostic imaging were revealed. We also compared the correlation between the two growth patterns with Fisch's classification, blood loss, lower cranial nerves (LCNs) deficit. RESULTS: There are 27 (69%) cases of Bi tumor and 17 (39%) cases of Be tumor. Significant radiomics features between the two growth patterns were demonstrated, ROC curves achieved excellent AUCs for MRI sequences (T1W1 MRI, MR contrast-enhanced sequence, MR complex sequences and MR complex + DSA by 0.833, 0.833, 0.875, 0.944) and had statistically significant in diagnosis of two growth patterns (P<0.05). There was no statistical correlation between growth patterns of JFPs and intra-operative blood loss. Preoperative LCNs deficits and Fisch's classification of tumors were correlated with the growth patterns of JFPs (P < 0.05). CONCLUSION: We proposetd two growth patterns of JFPs in term of the inferior petrous sinus involvement. Identification of Bi or Be growth patterns preoperatively is helpful to design optimal surgical strategies and minimize postoperative complications.

Practicality of multilayer round window reinforcement in the surgical management of superior semicircular canal dehiscence syndrome: a case report of long-term follow-up.

Several surgical techniques have been documented for approaching and repairing superior semicircular canal dehiscence syndrome (SCDS). These techniques encompass the trans-middle cranial fossa, transmastoid, endoscopic approaches, and round window reinforcement (RWR). RWR entails the placement of connective tissue with or without cartilage and around the round window niche, restricting the round window's movement to minimize the 3rd window effect and restore the bony labyrinth closer to its normal state. We employed the multilayer RWR technique, resulting in significant postoperative improvement and long-lasting effects for 3.7 years in 2 cases. Here, we present the clinical findings, surgical procedures, and the effectiveness of multilayer RWR. This technique can be the initial choice for surgical treatments of SCDS due to its high effectiveness, longer-lasting effect, and minimal risk of surgical complications.

Arteriovenous malformations in the cerebellopontine angle: assessment of the "backdoor resection" technique and microsurgical results in 38 patients.

OBJECTIVE: Posterior fossa arteriovenous malformations (AVMs) represent 7% to 15% of all intracranial AVMs and are associated with an increased risk of hemorrhage, morbidity, and mortality compared with supratentorial AVMs, thus prompting urgent and definitive treatment. Cerebellopontine angle (CPA) AVMs are a unique group of posterior fossa AVMs incorporating characteristics of brainstem and cerebellar lesions, which are particularly amenable to microsurgical resection. This study reports the clinical, radiological, operative, and outcome features of patients with CPA AVMs in a large cohort. METHODS: The authors conducted a single-surgeon, 2-institution retrospective cohort study of all consecutive patients with CPA AVMs treated with microsurgical resection during a 25-year period. RESULTS: CPA AVMs represented 22% (38 of 176) of all infratentorial AVMs resected by the senior author. Overall, 38 patients (22 [58%] male and 16 [42%] female) met the study inclusion criteria and were analyzed. Most patients presented with hemorrhage (n = 29, 76%). The median age at surgery was 56 (range 6-82) years. Subtypes included 22 (58%) petrosal cerebellar AVMs, 11 (29%) lateral pontine AVMs, and 5 (13%) AVMs involving both the brainstem and cerebellum. Most AVM niduses were small (< 3 cm; n = 35, 92%) and compact (n = 31, 82%). Fourteen (37%) patients harbored flow-related aneurysms. Twenty (53%) patients underwent preoperative embolization. Complete angiographic obliteration was achieved with microsurgery in 35 (92%) patients. Five (13%) patients with poor neurological conditions at presentation died before hospital discharge. Of the 7 (18%) patients with new postoperative neurological deficits, 5 had transient deficits. The median (interquartile range) follow-up was 1.7 (0.5-3.2) years; 32 (84%) patients were alive at last follow-up, and 30 (79%) had achieved a favorable neurological outcome (modified Rankin Scale [mRS] score 0-2). The only independent predictor of unfavorable postoperative outcome (mRS score 3-6) was the preoperative mRS score (p = 0.002). CONCLUSIONS: CPA AVMs are unique posterior fossa lesions, including petrosal cerebellar and lateral pontine AVMs. The "backdoor resection" technique provides a safe and efficient strategy with high obliteration rates and a low risk of treatment-related morbidity. Microsurgical resection should be considered the frontline treatment for most CPA AVMs, except for those with a significant diffuse brainstem component.

Meningioma originating from the superior petrosal vein without dural attachment: A case report.

BACKGROUND: Meningioma in the cerebellopontine angle (CPA) without dural attachment is extremely rare. We report a unique case of meningioma derived from the superior petrosal vein without dural attachment. CASE SUMMARY: A 44-year-old right-handed woman presented with a two-month history of headache and tinnitus. Brain magnetic resonance imaging showed a well-defined contrast-enhancing lesion in the right CPA without a dural tail sign. Tumor resection was performed using a right retro sigmoid approach. A dural attachment was not seen at the tentorium or posterior surface of the petrous pyramid. The tumor was firmly adherent to the superior petrosal vein. The origin site was cauterized and resected with the preservation of the superior petrosal vein. A diagnosis of meningothelial meningioma was made. The patient's headache and tinnitus gradually disappeared, and a recurrence was not observed five years after the surgery. CONCLUSION: The rare occurrence of meningioma without dural attachment makes it difficult to determine dural attachment before surgery. The absence of dural attachment makes it easy to completely resect such tumors. Vessels related to tumors should be removed carefully, considering the possible presence of tumor stem cells in the microvessels.

Superior semicircular canal dehiscence in relation with the superior petrosal sinus: our experience, surgical management and systematic review of literature.

PURPOSE: Most of Superior Semicircular Canal Dehiscence (SSCD) are located in the apical region of the SSC. However, in a small number of cases, it may be situated in the medial wall, causing the SSC to contact with the superior petrosal sinus (SPS). The aim of this study is to describe four patients with SSCD involving the superior petrosal sinus (SSCD-SPS) and to perform a review of the literature. METHODS: Observational retrospective study of patients diagnosed of SSCD-SPS in a tertiary referral center. A systematic review was made, identifying 7 articles in the literature. Clinical presentation, complementary test (pure-tone audiometry, PTA; vestibular evoked myogenic potential, VEMP; computed tomography, CT), therapeutic management and outcomes were reported. RESULTS: Four new cases of SSCD-SPS are reported, in three of them a transmastoid plugging was performed. 54 patients with SSCD-SPS (57 dehiscences) were reported in the literature. The most frequent symptoms were aural pressure (57.41%) and vertigo provoked by pressure/Valsalva (55.55%). Conductive hearing loss was the most common finding in PTA (47.37%). Abnormally low thresholds were observed in 59.46% of reported VEMP. Transmastoid approach was used in ten cases, middle fossa approach in four, round window reinforcement in one, and occlusion of the SPS using coils in two. CONCLUSIONS: Within SSCD, we have encountered a rare subtype characterized by its medial wall location in close proximity to the SPS. This subgroup needs special consideration as it has shown its own distinct characteristics. Regarding therapeutic management, we advocate a transmastoid approach.

ACTH-dependent Cushing Syndrome with No Peripheral Response But a Marked Petrosal Sinus ACTH Response to Desmopressin.

Desmopressin is increasingly used for the diagnosis of Cushing disease (CD) since corticotropin-releasing hormone became unavailable. We report the case a 32-year-old man who presented with overt Cushing syndrome. Morning blood cortisol, ACTH, 1 mg dexamethasone suppression test, 24-hour urinary free cortisol, and bedtime salivary cortisol were highly variable, reaching markedly elevated values. Intravenous desmopressin administration produced no ACTH or cortisol increase. Pituitary magnetic resonance imaging, thoracic computed tomography, and DOTATATE positron emission tomography scan identified no lesion. Inferior petrosal sinus sampling (IPSS) with desmopressin stimulation resulted in elevated central-to-peripheral ACTH ratio and prolactin co-secretion, while peripheral ACTH remained stable. No corticotroph tumor was identified on pituitary surgery pathology. Hypercortisolism persisted postoperatively. Cabergoline was initiated, after which the patient rapidly developed transient severe adrenal insufficiency (AI). Bilateral adrenalectomy was performed in view of persistent hypercortisolism. This is an unusual case of petrosal sinus ACTH response to desmopressin without any peripheral response, suggesting a central source of ACTH. Thus, desmopressin should still be used during IPSS in patients with no peripheral response. It is unclear whether the AI episode resulted from a combination of nadir of cyclic hypercortisolism, partial apoplexy, and response to cabergoline of an occult corticotroph tumor.

Bilateral Inferior Petrosal Sinus Sampling Without Lateralization Is Less Accurate for the Diagnosis of Cushing Disease.

Context: During bilateral inferior petrosal sinus sampling (BIPSS), the side-to-side adrenocorticotropic hormone (ACTH) ratio, referred to as sampling lateralization, was used to predict pituitary adenoma localization. Objective: To investigate the potential different diagnostic accuracy of BIPSS for differentiating Cushing disease (CD) and ectopic ACTH secretory syndrome (EAS) patients with low lateralization (inferior petrosal sinus [IPS]:IPS ≤ 1.4) and high lateralization (IPS:IPS > 1.4). Methods: This single-center retrospective study (2011-2021) included (all patients had BIPSS results and confirmed pathologic diagnoses) 220 consecutive CD patients (validation set), 30 EAS patients, and 40 of the CD patients who had digital subtraction angiography (DSA) videos (discovery set). Results: In the discovery set, the low-lateralization CD group (n = 11) had a higher median plasma ACTH concentration (62.2, IQR 44.7-181.0 ng/L) than the high-lateralization CD group (n = 29) (33.0, IQR 18.5-59.5, P = .013). Lower IPS to peripheral ratios were observed in the low-lateralization group during BIPSS, both before and after stimulation (P = .013 and P = .028). The sensitivity of BIPSS before stimulation in differentiating CD from EAS was lower in the low-lateralization group than the high-lateralization group (54.6% vs 93.1%, P = .003), as validated in the validation set. DSA videos revealed higher vascular area difference visible in the 2 sides of the pituitary in low lateralization (median 1.2 × 105 pixels, IQR 0.5-1.8) than the high-lateralization group (0.4 × 105 pixels, IQR 0.1-0.7, P = .008). The vascular area ratio of the 2 sides was also significantly higher in low (1.55, IQR 1.31-2.20) than high lateralization (1.19, IQR 1.07-1.35, P = .010). Conclusion: Our study suggested that low lateralization in CD patients may reduce the diagnostic sensitivity of BIPSS, which might be potentially associated with peripituitary vascular anatomy.

Bilateral inferior petrosal sinus sampling in the differential diagnosis of ACTH-dependent Cushing's syndrome: A reappraisal.

Cushing's syndrome (CS) is a rare disorder, once exogenous causes have been excluded. However, when diagnosed, the majority of cases are adrenocorticotropic hormone (ACTH)-dependent, of which a substantial minority are due to a source outside of the pituitary, ectopic ACTH syndrome (EAS). Differentiating among pituitary-dependent CS, Cushing's disease (CD) and an ectopic source can be problematic. Because non-invasive tests in the evaluation of CS patients often lack adequate sensitivity and specificity, bilateral inferior petrosal sinus sampling (BIPSS), a minimally invasive procedure performed during the investigation of ACTH-dependent CS, can be extremely helpful. BIPSS is considered to be the gold standard for differentiating CD from the EAS. Furthermore, although such differentiation may indeed be challenging, BIPSS is itself a complex investigation, especially in recent times due to the widespread withdrawal of corticotrophin-releasing hormone and its replacement by desmopressin. We review current published data on this investigation and, in the light of this and our own experience, discuss its appropriate use in diagnostic algorithms.

The diagnostic yield of inferior petrosal sinus sampling in Cushing syndrome in the era of ovine CRH shortage.

PURPOSE: The ovine corticotropin-releasing hormone (oCRH) stimulation test has been routinely used in the diagnostic work-up of ACTH-dependent Cushing syndrome (CS). With oCRH currently being out-of-stock in Europe, we aimed at evaluating the diagnostic performance of inferior petrosal sinus sampling (IPSS) without oCRH stimulation. METHODS: We compared the values of 40 patients with ACTH-dependent CS and negative MRI findings in whom ACTH was measured before and after oCRH stimulation. RESULTS: The ratio of central-to-peripheral ACTH measurement (IPS:P) before the combined 3, 5, and 10 min of oCRH stimulation yielded diminished sensitivity (85% vs. 97%), alongside markedly decreased specificity (57% vs. 71%), as well as reduced positive and negative predictive values (90% vs. 94% and 44% vs. 83%), respectively. CONCLUSIONS: With the current drug shortages in Europe, ACTH measurements without oCRH stimulation in IPSS cannot be recommended. Thus, we call for desmopressin or the commercially available human CRH as a potential alternative in the confirmation of ACTH excess by IPSS in equivocal MRI findings.

The trans-sylvian trans-petrosal "half & half" approach-a how I do it.

BACKGROUND: Petroclival meningiomas are one of the most challenging tumors to be operated in the realm of neurosurgery. Many approaches have been developed over the years. METHOD: The authors describe the Half & Half (H&H) approach whose main indication is petroclival meningiomas with suprasellar extension. The part of the tumor located above CN III and in the retrochiasmatic space is addressed through a trans-sylvian, while the petroclival portion is through an extradural anterior petrosectomy approach. The wide surgical corridor given by this approach allows extensive tumor resection while avoiding the risk associated with the manipulation of intracavernous neurovascular structures. CONCLUSION: The H&H approach is an effective strategy to maximize the safe resection of petroclival meningiomas.

Personalized non-invasive diagnostic algorithms based on urinary free cortisol in ACTH-dependant Cushing's syndrome.

CONTEXT: Current guidelines for distinguishing Cushing's disease (CD) from ectopic ACTH secretion (EAS) are questionable, as they use pituitary MRI as first-line investigation for all patients, CRH testing is no longer available and they suggest performing inferior petrosal sinus sampling (BIPPS), an invasive and rarely available investigation, in many patients. OBJECTIVE: To establish non-invasive personalized diagnostic strategies based on the probability of EAS estimated from simple baseline parameters. DESIGN: Retrospective study. SETTING: University hospitals. PATIENTS: 247 CD and 36 EAS patients evaluated between 2001 and 2023 in 2 French hospitals. A single-center cohort of 105 Belgian patients served for external validation. RESULTS: 24h-urinary free cortisol (UFC) had the highest area under ROC curve for discrimination of CD from EAS (0·96 [95% CI, 0·92-0·99] in the primary study and 0·99 [95% CI, 0·98-1·00] in the validation cohort). The addition of clinical, imaging and biochemical parameters did not improve EAS prediction over UFC alone, with only BIPPS showing a modest improvement (c-statistic index 0·99 [95% CI, 0·97-1·00]). 3 groups were defined based on baseline UFC: < 3 (group one), 3-10 (group 2) and > 10 x the upper limit of normal (group 3), and were associated with 0%, 6·1% and 66·7% prevalence of EAS, respectively. Diagnostic approaches performed in our cohort support the use of pituitary MRI alone in group one, MRI first followed by neck-to-pelvis CT-scan (npCT) when negative in group 2, and npCT first followed by pituitary MRI when negative in group 3. When not combined with the CRH test, the desmopressin test has limited diagnostic value. CONCLUSION: UFC accurately predicts EAS and can serve to define personalized and non-invasive diagnostic algorithms.

Machine Learning May Be An Alternative To BIPSS In The Differential Diagnosis Of ACTH-Dependent Cushing's Syndrome.

OBJECTIVE: This study aimed to develop machine learning (ML) algorithms for the differential diagnosis of adrenocorticotropic hormone (ACTH)-dependent Cushing's syndrome (CS) based on biochemical and radiological features. METHODS: Logistic regression algorithms were used for ML, and the area under the receiver operating characteristics curve (AUROC) was used to measure performance. We used Shapley Contributed Comments (SHAP) values, which help explain the results of the ML models to identify the meaning of each feature and facilitate interpretation. RESULTS: A total of 106 patients, 80 with Cushing's disease (CD) and 26 with ectopic ACTH syndrome (EAS), were enrolled in the study. The ML task was created to classify patients with ACTH-dependent CS into CD and EAS. The average AUROC value obtained in the cross-validation of the logistic regression model created for the classification task was 0.850. The diagnostic accuracy of the algorithm was 86%. The SHAP values indicated that the most important determinants for the model were the 2-day 2-mg dexamethasone suppression test, the > 50% suppression in the 8-mg high-dose dexamethasone test, late-night salivary cortisol, and the diameter of the pituitary adenoma. We have also made our algorithm available to all clinicians via a user-friendly interface. CONCLUSION: ML algorithms have the potential to serve as an alternative decision support tool to invasive procedures in the differential diagnosis of ACTH-dependent CS.

Dural arteriovenous fistula involving superior petrosal sinus with petrosal venous drainage in association with cerebral venous thrombosis: Literature review and illustrative case.

Background: Dural arteriovenous fistulas (DAVFs) involving superior petrosal sinus (SPS) and superior petrosal vein (SPV) are extremely rare. The pathogenesis of these fistulas remains unclear. We are illustrating 2 cases of DAVFs involving the superior petrosal sinus and veins associated with venous sinus thrombosis with a literature review. Methods: We reviewed the literature using the PRISMA (preferred reporting items for systematic reviews and meta-analyses) guidelines focusing on DAVFs involving the SPS and/or SPV. Additionally, we searched for additional articles through the reference lists of the included studies. Results: Our review yielded 20 articles from 1997 until 2022 involving 33 patients with 34 fistulas, including our 2 patients. The mean age was 55.1 ± 12.9 years (range 25-85), 54.5% were males (n = 18). The patients presented with hemorrhage in 36.4% (n = 12), and progressive myelopathy in 30.3% (n = 10). Most fistulas often had arterial supply from MMA, MHT, and/or OA. The fistulas had infratentorial drainage in 64.71% (n = 22), supratentorial drainage in 23.53% (n = 8), and both supra and infratentorial drainage in 11.76% (n = 4). In 27.3% (n = 9), cerebral venous thrombosis was mentioned or identified. Endovascular treatment was performed in 47.1% of cases (n = 16), surgery in 29.4% (n = 10), and combination of treatments in 23.5% (n = 8). A total of 30.3% (n = 10) of cases had incomplete recovery or poor result. Conclusion: DAVFs involving the SPS and/or SPV are associated with aggressive natural history, requiring early diagnosis and prompt treatment, leading to good prognosis. These fistulas may be acquired in origin, probably secondary to cerebral venous thrombosis.

The historical adventures of Takeshi Kawase: the mountaineer who explored the "no man's land" with love for art, nature, and humankind.

The anterior petrosal approach, or Kawase's approach, is a commonly used technique in skull base surgery to access the brainstem in the posterior fossa from the middle fossa, and has the advantages of minimizing brain retraction and preserving hearing. It was first successfully performed by the legendary Japanese neurosurgeon, Takeshi Kawase, for the clipping of a basilar artery aneurysm in 1981. To date, no historical article has shed light on Kawase's intriguing personal history. In this historical vignette, the authors depict Kawase's unique background, talent, passion, as well as struggles that ultimately shaped his career. By sharing Kawase's personal story from the hospital where he first successfully performed his original approach, the authors hope to pass on to future generations Kawase's spirit and philosophy that have impacted the global neurosurgical community.