Modified Skin Incision and Location of Burr-Hole Surgery via a Retrosigmoid Approach: An Anatomical Study

Objective This study aims to reduce the tissue damage during craniotomy with retrosigmoid approach. A modified sickle-shaped skin incision was developed, and a new burr-hole positioning method was proposed. Methods Five adult cadaveric heads (10 sides) were used in this study. The sickle-shaped skin incision was performed during craniotomy. The nerves, blood vessels, and muscles were observed and measured under a microscope. Additionally, 62 dry adult skull specimens (left sided, n = 35; right sided, n = 27) were used to measure the distance between the most commonly used locating point (asterion [Ast] point) and the posteroinferior point of the transverse sigmoid sinus junction (PSTS) (Ast-PSTS), as well as the distance between the new locating O point and the PSTS (O-PSTS). Then, the reliability of the new locating O point was validated on the same five adult cadaveric heads (10 sides) used for the sickle-shaped skin incision. Results The sickle-shaped skin incision reduced the damage to the occipital nerves, blood vessels, and muscles during the surgery via a retrosigmoid approach. The dispersion and variability of O-PSTS were smaller than those of Ast-PSTS. Conclusion The sickle-shaped skin incision of the retrosigmoid approach can reduce the tissue damage and can completely expose the structures in the cerebellopontine angle. The modified O point is a more reliable locating point for a burr-hole surgery than the Ast point.

Study on the correlation between hemodynamic status of the transverse sinus-sigmoid sinus and the clinical efficacy of sigmoid sinus wall reconstruction

Background and Purpose For patients with pulsatile tinnitus who have both transverse sinus stenosis and sigmoid sinus wall anomalies, sigmoid sinus wall reconstruction surgery is the first-choice treatment when the trans-stenotic pressure gradient less than 10 mmHg. However, not all patients are cured by surgery. We hypothesized the abnormal hemodynamics caused by transverse sinus stenosis is associated with the clinical efficacy of surgery. Methods Eight pulsatile tinnitus patients treated with surgery were retrospectively reviewed (4 rehabilitated, 4 nonrehabilitated). All patients had radiologically diagnosed transverse sinus stenosis and sigmoid sinus wall anomalies. A numerical simulation of the hemodynamics of the transverse sinus-sigmoid sinus was performed using computational fluid dynamics technology. Changes in the blood flow patterns before and after surgery were observed. The blood flow velocity at the stenosis, vorticity of blood flow in the sigmoid sinus and wall pressure distribution in the sigmoid sinus wall anomalies area were compared. Results The blood flow velocity in the stenosis (preoperative P = 0.04, postoperative P = 0.004) and vorticity in the sigmoid sinus (preoperative P = 0.02, postoperative P = 0.007) pre- and post-surgery were significantly higher in the non-rehabilitation group than in the rehabilitation group. No significant difference was found in the wall pressure distribution in the sigmoid sinus wall anomalies area (preoperative P = 0.12, postoperative P = 0.24). Conclusions There is a clear correlation between the abnormal hemodynamic status caused by transverse sinus stenosis and the clinical efficacy of surgery. The blood flow velocity at the stenosis and vorticity of blood flow in the sigmoid sinus are factors influencing the clinical efficacy of surgery.

Successful treatment of cerebral venous sinus thrombosis by balloon venoplasty: a case report

Cerebral venous sinus thrombosis is a special cerebrovascular disease affecting young adult and middle-aged people. The clinical manifestations of cerebral venous sinus thrombosis are diverse and nonspecific; thus, imaging plays an important role in early diagnosis. Anticoagulation with heparin is the preferred treatment for cerebral venous sinus thrombosis. Endovascular treatment is also being increasingly used to achieve recanalization of the cerebral venous sinus. We herein describe a woman in her early 50s who was diagnosed with cerebral venous sinus thrombosis for which anticoagulation with heparin was ineffective. To improve her symptoms and prognosis, we selected balloon venoplasty to treat the right sigmoid sinus thrombosis. Her condition subsequently improved, and no recurrence was observed after several follow-ups.

Effect of Emissary Vein on Hemodynamics of the Transverse- Sigmoid Sinus Junction

Objective: To investigate the effect of the blood flow direction and afflux location of emissary veins (EVs) on the hemodynamics of the transverse-sigmoid sinus (TS-SS) junction.Methods: A patient-specific geometric model was constructed using computed tomography venography (CTV) and 4D flow MR data from a venous pulsatile tinnitus (PT) patient. New EV models were assembled with the afflux at the superior, middle and inferior portions of the SS from the original model, and inlet and outlet directions were applied. Computational fluid dynamics (CFD) simulation was performed to analyze the wall pressure and flow pattern of the TS-SS junction in each condition.Results: Compared to the model without EVs, the wall pressure was greatly increased in models with inlet flow and greatly decreased in models with outlet flow. The more closely the EV approached the TS-SS, the larger the pressure in models with inlet flow, and the smaller the pressure in models with outlet flow. The flow streamline in the lateral part of the TS-SS junction was smooth in all models. The streamlines in the medial part were regular spirals in outlet models and chaotic in inlet models. The streamlines showed no obvious changes regardless of afflux location. The velocity at the TS-SS junction of inlet models were uniform, medium-low flow rate, while in control and outlet models were the lateral high flow rate and the central low flow rate.Conclusion: The flow direction and afflux location of EVs affect the hemodynamics of the TS-SS junction, which may influence the severity of PT.

Cerebral Sinovenous Thrombosis in Greek Children: A Single Centre Experience

Introduction: Cerebral sinovenous thrombosis (CSVT) in children is a rare, often underdiagnosed but serious event. The risk factors in children include head or neck infections, prothrombotic agents such as oral contraceptives and a chronic systemic illness. In the present study, we aimed to investigate the clinical manifestations, neuroimaging findings, risk factors and treatment of children suffering from CSVT in a reference paediatric centre for thrombosis. In addition, we assessed outcomes after CSVT. Methods: Data were retrospectively collected for children with CSVT, referred between 2010 and 2020 to our hospital. There were 103 children that were used as controls concerning thrombophilic factors. The categorical variables were described by frequency distributions and compared with x2-homogeneity test. Results: Sixty-five patients were included in the study (58% males). The mean age of the children at the time of diagnosis was 6.2 years (SD 4 years, range 1 month to 16 years). The most common presenting symptoms were headache (43%), decreased consciousness (32%), vomiting (12%), seizures (15%), diplopia (6%) and torticollis (5%). Papilloedema was found in 14 children (21.5%) and intracerebral haemorrhage in one. The most frequent risk factors were infections (74%), mainly acute otitis media with or without mastoiditis (55% και 19% respectively) and chronic medical conditions, such as polycythemia vera, nephrotic syndrome, arteriovenous malformation, ulcerative colitis-3% each. The use of oral contraceptives was not documented. For the diagnostic evaluation MRI/Magnetic Resonance Venography was performed in 72.3% of children. CT was diagnostic in 24.6% of patients and one infant underwent Power Doppler Ultrasound. Thrombosis was detected in 46% of children on left side, in 34% on right side and in 20% bilaterally. The deep venous system (straight venous, vein of Galen, transverse and sigmoid sinus, jugular veins) was more commonly affected (75%). Notably, sigmoid sinus thrombosis (40%) was predominantly involved, followed by transverse (31%), while extension to ipsilateral jugular vein occurred in 32%. Multiple sinus involvement was found in 64% of patients. Interestingly, simultaneous localization in the transverse and sigmoid sinuses had an increased probability of being accompanied by papilloedema (p <0.05). Venous infarctions were noticed in two children, while one child with hypoplastic venous sinus had an abdominal peritoneal CNS drain. Laboratory investigations for prothrombotic risk factors were available for all patients. One or more prothrombotic risk factor were found in 18 of the 65 (28%) children. To be more accurate, heterozygosity for FVLeiden and FII20210A mutations were found in 8% and 5% of patients, respectively and homozygosity for MTHFR-C776T in 15% (without raised homocysteine). Thrombophilic factors did not attain statistically significant results, apart from a trend for heterozygosity for FVLeiden and FII20210A mutations in patients (in controls 5% and 3% respectively). All patients received anticoagulation (68% coumarin anticoagulants, 32% Low Molecular Weight Heparin) for a mean duration of 7.5 ±3.3 months and 18.8 ±32.4 months respectively, while 7 children still receive anticoagulation. The duration of anticoagulation therapy was based on clinical outcome and follow-up investigations. No patient developed hemorrhagic events during the therapy. Follow-up imaging studies were available in most of the children. Six children showed no recanalization on 3.5 ±0.5 months, 19 children showed partial recanalization on 5±3 months and 20 children showed complete recanalization on 7± 5 months. No child died or had persisting neurological sequelae, apart from signs of attention deficit disorder, during a median follow-up of 4±3 years. One patient underwent remission of thrombosis in other site (pulmonary emboli) in adulthood. Conclusions: Physicians should be suspicious of CSVT in children with otitis media/mastoiditis or chronic diseases, when referred for headache or other neurological signs. In a quarter of the cases a thrombophilic factor had eventually some contribution to the event. Longer follow-up may reveal the incidence of cognitive or behavioral disabilities due to CSVT. Disclosures Kattamis: Novartis: Consultancy, Honoraria, Research Funding; CRISPR/Vertex: Consultancy, Honoraria; Chiesi: Honoraria; BMS/Celgene: Consultancy, Honoraria, Research Funding; Agios Pharmaceuticals: Consultancy; IONIS: Consultancy; VIFOR: Consultancy; Amgen: Consultancy.