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Krishna C. Joshi, Hamid Borghei-Razavi and Varun R. Kshettry

Brainstem cavernomas are benign, angiographically occult, low-flow lesions and constitute 18%–35% of intracranial cavernomas.4,6 They are known to have an annual rupture risk of 2%–6%,2,5 and once symptomatic, they frequently cause progressive neurological morbidity. A 22-year-old lady presented with progressive profound neurologic deficits from three distinct hemorrhages over 2 months. Surgery was indicated given the aggressive natural history, and the lesion now presented to the surface with displacement of corticospinal tracts noted on diffusion tensor imaging.1,7 We describe a surgical technique via an orbitozygomatic transsylvian pretemporal approach with uncal resection to open the oculomotor-tentorial window and resect the lesion.3

The video can be found here: https://youtu.be/j5yYp4OsaRc.

Free access

André Beer-Furlan, Hormuzdiyar H. Dasenbrock, Krishna C. Joshi and Michael Chen

Acute basilar artery occlusion is one of the most devastating subtypes of ischemic stroke with an extremely high morbidity and mortality rate. The most common causes include embolism, large-artery atherosclerosis, penetrating small-artery disease, and arterial dissection. The heart and vertebral arteries are the main source of emboli in embolic basilar occlusions. The authors present an uncommon acute basilar occlusion secondary to a fusiform aneurysm with intraluminal thrombus. The patient underwent a mechanical thrombectomy with successful recanalization, but persistent intraluminal thrombus. The authors discuss the management dilemma and describe their choice for placement of flow diverter stents.

The video can be found here: https://youtu.be/XzBdgxJPSWQ.

Free access

André Beer-Furlan, Hormuzdiyar H. Dasenbrock, Krishna C. Joshi and Michael Chen

Tentorial dural arteriovenous fistulas (DAVFs) are uncommon, complex fistulas located between the leaves of the tentorium cerebelli with a specific anatomic and clinical presentation characterized by high hemorrhagic risk. They have an extensive arterial supply and complex venous drainages, making them difficult to treat. There is recent literature favoring treatment through an endovascular transarterial route. The authors present an uncommon tentorial/ambient cistern region DAVF with feeders arising from the external and internal carotid arteries. The patient underwent a combined transarterial and transvenous approach with successful obliteration of the DAVF. The authors discuss the management challenges faced in this case.

The video can be found here: https://youtu.be/VXDD8zUvsSQ.

Free access

André Beer-Furlan, Krishna C. Joshi, Hormuzdiyar H. Dasenbrock and Michael Chen

Superior sagittal sinus (SSS) dural arteriovenous fistulas (DAVFs) are rare and present unique challenges to treatment. Complex, often bilateral, arterial supply and involvement of large volumes of eloquent cortical venous drainage may necessitate multimodality therapy such as endovascular, microsurgical, and stereotactic radiosurgery techniques. The authors present a complex SSS DAVF associated with an occluded/severely stenotic SSS. The patient underwent a successful endovascular transvenous approach with complete obliteration of the SSS. The authors discuss the management challenges faced on this case.

The video can be found here: https://youtu.be/-rztg0_cBXY.

Full access

Umesh Srikantha, Kiran S. Khanapure, Aniruddha T. Jagannatha, Krishna C. Joshi, Ravi G. Varma and Alangar S. Hegde

OBJECTIVE

Minimally invasive techniques are being increasingly used to treat disorders of the cervical spine. They have a potential to reduce the postoperative neck discomfort subsequent to extensive muscle dissection associated with conventional atlantoaxial fusion procedures. The aim of this paper was to elaborate on the technique and results of minimally invasive atlantoaxial fusion.

MATERIALS

Minimally invasive atlantoaxial fusion was done initially in 4 fresh-frozen cadavers and subsequently in 5 clinical cases. Clinical cases included patients with reducible atlantoaxial instability and undisplaced or minimally displaced odontoid fractures. The surgical technique is illustrated in detail.

RESULTS

Among the cadaveric specimens, all C-1 lateral mass screws were in the correct position and 2 of the 8 C-2 screws had a vertebral canal breach. Among clinical cases, all C-1 lateral mass screws were in the correct position. Only one C-2 screw had a Grade 2 vertebral canal breach, which was clinically insignificant. None of the patients experienced neurological worsening or implant-related complications at follow-up. Evidence of rib graft fusion or C1–2 joint fusion was successfully demonstrated in 4 cases, and flexion-extension radiographs done at follow-up did not show mobility in any case.

CONCLUSIONS

Minimally invasive atlantoaxial fusion is a safe and effective alternative to the conventional approach in selected cases. Larger series with direct comparison to the conventional approach will be required to demonstrate clinical benefit presumed to be associated with a minimally invasive approach.

Free access

Krishna C. Joshi, Daniel M. Heiferman, André Beer-Furlan and Demetrius K. Lopes

External carotid artery (ECA) to internal carotid artery (ICA) bypass is a well-established procedure for the treatment of chronic ischemic diseases of the carotid artery. Rarely de novo aneurysms can develop at the site of anastomosis. The treatment of these aneurysms can be very challenging due to various factors, including the presence of graft, previous craniotomy, atherosclerotic vessels, and lack of direct access. In this video the authors report and discuss the management of a right middle cerebral artery (MCA) wide-necked de novo aneurysm by stent-assisted coiling through a retrograde trans-posterior communicating artery access.

The video can be found here: https://youtu.be/MBKolPvOErU.

Free access

Krishna Chaitanya Joshi, Ignacio Larrabide, Ahmed Saied, Nada Elsaid, Hector Fernandez and Demetrius K. Lopes

OBJECTIVE

The authors sought to validate the use of a software-based simulation for preassessment of braided self-expanding stents in the treatment of wide-necked intracranial aneurysms.

METHODS

This was a retrospective, observational, single-center study of 13 unruptured and ruptured intracranial aneurysms treated with braided self-expanding stents. Pre- and postprocedural angiographic studies were analyzed. ANKYRAS software was used to compare the following 3 variables: the manufacturer-given nominal length (NL), software-calculated simulated length (SL), and the actual measured length (ML) of the stent. Appropriate statistical methods were used to draw correlations among the 3 lengths.

RESULTS

In this study, data obtained in 13 patients treated with braided self-expanding stents were analyzed. Data for the 3 lengths were collected for all patients. Error discrepancy was calculated by mean squared error (NL to ML −22.2; SL to ML −6.14, p < 0.05), mean absolute error (NL to ML 3.88; SL to ML −1.84, p < 0.05), and mean error (NL to ML −3.81; SL to ML −1.22, p < 0.05).

CONCLUSIONS

The ML was usually less than the NL given by the manufacturer, indicating significant change in length in most cases. Computational software-based simulation for preassessment of the braided self-expanding stents is a safe and effective way for accurately calculating the change in length to aid in choosing the right-sized stent for optimal placement in complex intracranial vasculature.

Free access

Krishna C. Joshi, Alankrita Raghavan, Baha’eddin Muhsen, Jason Hsieh, Hamid Borghei-Razavi, Samuel T. Chao, Gene H. Barnett, John H. Suh, Gennady Neyman, Varun R. Kshettry, Pablo F. Recinos, Alireza M. Mohammadi and Lilyana Angelov

OBJECTIVE

Gamma Knife radiosurgery (GKRS) has been successfully used for the treatment of intracranial meningiomas given its steep dose gradients and high-dose conformality. However, treatment of skull base meningiomas (SBMs) may pose significant risk to adjacent radiation-sensitive structures such as the cranial nerves. Fractionated GKRS (fGKRS) may decrease this risk, but until recently it has not been practical with traditional pin-based systems. This study reports the authors’ experience in treating SBMs with fGKRS, using a relocatable, noninvasive immobilization system.

METHODS

The authors performed a retrospective review of all patients who underwent fGKRS for SBMs between 2013 and 2018 delivered using the Extend relocatable frame system or the Icon system. Patient demographics, pre- and post-GKRS tumor characteristics, perilesional edema, prior treatment details, and clinical symptoms were evaluated. Volumetric analysis of pre-GKRS, post-GKRS, and subsequent follow-up visits was performed.

RESULTS

Twenty-five patients met inclusion criteria. Nineteen patients were treated with the Icon system, and 6 patients were treated with the Extend system. The mean pre-fGKRS tumor volume was 7.62 cm3 (range 4.57–13.07 cm3). The median margin dose was 25 Gy delivered in 4 (8%) or 5 (92%) fractions. The median follow-up time was 12.4 months (range 4.7–17.4 months). Two patients (9%) experienced new-onset cranial neuropathy at the first follow-up. The mean postoperative tumor volume reduction was 15.9% with 6 patients (27%) experiencing improvement of cranial neuropathy at the first follow-up. Median first follow-up scans were obtained at 3.4 months (range 2.8–4.3 months). Three patients (12%) developed asymptomatic, mild perilesional edema by the first follow-up, which remained stable subsequently.

CONCLUSIONS

fGKRS with relocatable, noninvasive immobilization systems is well tolerated in patients with SBMs and demonstrated satisfactory tumor control as well as limited radiation toxicity. Future prospective studies with long-term follow-up and comparison to single-session GKRS or fractionated stereotactic radiotherapy are necessary to validate these findings and determine the efficacy of this approach in the management of SBMs.

Free access

Baha’eddin A. Muhsen, Krishna C. Joshi, Bryan S. Lee, Bicky Thapa, Hamid Borghei-Razavi, Xuefei Jia, Gene H. Barnett, Samuel T. Chao, Alireza M. Mohammadi, John H. Suh, Michael A. Vogelbaum and Lilyana Angelov

OBJECTIVE

Gamma Knife radiosurgery (GKRS) as monotherapy is an option for the treatment of large (≥ 2 cm) posterior fossa brain metastases (LPFMs). However, there is concern regarding possible posttreatment increase in peritumoral edema (PTE) and associated compression of the fourth ventricle. This study evaluated the effects and safety of GKRS on tumor and PTE control in LPFM.

METHODS

The authors performed a single-center retrospective review of 49 patients with 51 LPFMs treated with GKRS. Patients with at least 1 clinical and radiological follow-up visit were included. Tumor, PTE, and fourth ventricle volumetric measurements were used to assess efficacy and safety. Overall survival was a secondary outcome.

RESULTS

Fifty-one lesions in 49 consecutive patients were identified; 57.1% of patients were male. At the time of GKRS, the median age was 61.5 years, and the median Karnofsky Performance Status score was 90. The median number of LPFMs and overall brain metastases were 1 and 2, respectively. The median overall tumor, PTE, and fourth ventricle volumes at diagnosis were 4.96 cm3 (range 1.4–21.1 cm3), 14.98 cm3 (range 0.6–71.8 cm3), and 1.23 cm3 (range 0.3–3.2 cm3), respectively, and the median lesion diameter was 2.6 cm (range 2.0–5.07 cm). The median follow-up time was 7.3 months (range 1.6–57.2 months). At the first follow-up, 2 months posttreatment, the median tumor volume decreased by 58.66% (range −96.95% to +48.69%, p < 0.001), median PTE decreased by 78.10% (range −99.92% to +198.35%, p < 0.001), and the fourth ventricle increased by 24.97% (range −37.96% to +545.6%, p < 0.001). The local control rate at first follow-up was 98.1%. The median OS was 8.36 months. No patient required surgical intervention, external ventricular drainage, or shunting between treatment and first follow-up. However, 1 patient required a ventriculoperitoneal shunt at 23 months from treatment. Posttreatment, 65.30% received our general steroid taper, 6.12% received no steroids, and 28.58% required prolonged steroid treatment.

CONCLUSIONS

In this retrospective analysis, patients with LPFMs treated with GKRS had a statistically significant posttreatment reduction in tumor size and PTE and marked opening of the fourth ventricle (all p < 0.001). This study demonstrates that GKRS is well tolerated and can be considered in the management of select cases of LPFMs, especially in patients who are poor surgical candidates.

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Ching-Jen Chen, Cheng-Chia Lee, Hideyuki Kano, Kathryn N. Kearns, Dale Ding, Shih-Wei Tzeng, Ahmet Atik, Krishna Joshi, Gene H. Barnett, Paul P. Huang, Douglas Kondziolka, David Mathieu, Christian Iorio-Morin, Inga S. Grills, Thomas J. Quinn, Zaid A. Siddiqui, Kim Marvin, Caleb Feliciano, Andrew Faramand, L. Dade Lunsford and Jason P. Sheehan

OBJECTIVE

Contrary to the better described obliteration- and hemorrhage-related data after stereotactic radiosurgery (SRS) of brain arteriovenous malformations (AVMs) in pediatric patients, estimates of the rarer complications, including cyst and tumor formation, are limited in the literature. The aim of the present study was to assess the long-term outcomes and risks of SRS for AVMs in pediatric patients (age < 18 years).

METHODS

The authors retrospectively analyzed the International Radiosurgery Research Foundation pediatric AVM database for the years 1987 to 2018. AVM obliteration, post-SRS hemorrhage, cyst formation, and tumor formation were assessed. Cumulative probabilities, adjusted for the competing risk of death, were calculated.

RESULTS

The study cohort comprised 539 pediatric AVM patients (mean follow-up 85.8 months). AVM obliteration was observed in 64.3% of patients, with cumulative probabilities of 63.6% (95% CI 58.8%–68.0%), 77.1% (95% CI 72.1%–81.3%), and 88.1% (95% CI 82.5%–92.0%) over 5, 10, and 15 years, respectively. Post-SRS hemorrhage was observed in 8.4% of patients, with cumulative probabilities of 4.9% (95% CI 3.1%–7.2%), 9.7% (95% CI 6.4%–13.7%), and 14.5% (95% CI 9.5%–20.5%) over 5, 10, and 15 years, respectively. Cyst formation was observed in 2.1% of patients, with cumulative probabilities of 5.5% (95% CI 2.3%–10.7%) and 6.9% (95% CI 3.1%–12.9%) over 10 and 15 years, respectively. Meningiomas were observed in 2 patients (0.4%) at 10 and 12 years after SRS, with a cumulative probability of 3.1% (95% CI 0.6%–9.7%) over 15 years.

CONCLUSIONS

AVM obliteration can be expected after SRS in the majority of the pediatric population, with a relatively low risk of hemorrhage during the latency period. Cyst and benign tumor formation after SRS can be observed in 7% and 3% of patients over 15 years, respectively. Longitudinal surveillance for delayed neoplasia is prudent despite its low incidence.