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Papers by Torin Karsonovich

Cureus, Apr 15, 2020

Endovascular stenting and balloon angioplasty is a feasible although controversial option for int... more Endovascular stenting and balloon angioplasty is a feasible although controversial option for intracranial atherosclerotic stenosis refractory to maximize medical management. High rates of symptomatic in-stent restenosis (ISR) have been identified with Wingspan stent (Stryker, Fremont, CA, USA) placement. Revascularization of ISR by way of re-stenting is often attempted, albeit with high risk and low durability. In lesions with long-segment non-focal critical or emergent occluded stenosis, re-stenting with a single balloon mounted stent is not possible due to deliverability of a lengthy device through a tortuous carotid siphon. Tandem drug-eluting stent placement within the middle cerebral artery to address acute, occlusive ISR using a Wingspan stent, with additional stent reconstruction, has not been previously described.

Neurosurgery, Sep 15, 2021

BACKGROUNDDespite the well-documented utility of responsive neurostimulation (RNS, NeuroPace) in ... more BACKGROUNDDespite the well-documented utility of responsive neurostimulation (RNS, NeuroPace) in adult epilepsy patients, literature on the use of RNS in children is limited.OBJECTIVETo determine the real-world efficacy and safety of RNS in pediatric epilepsy patients.METHODSPatients with childhood-onset drug-resistant epilepsy treated with RNS were retrospectively identified at 5 pediatric centers. Reduction of disabling seizures and complications were evaluated for children (<18 yr) and young adults (>18 yr) and compared with prior literature pertaining to adult patients.RESULTSOf 35 patients identified, 17 were <18 yr at the time of RNS implantation, including a 3-yr-old patient. Four patients (11%) had concurrent resection. Three complications, requiring additional surgical interventions, were noted in young adults (2 infections [6%] and 1 lead fracture [3%]). No complications were noted in children. Among the 32 patients with continued therapy, 2 (6%) achieved seizure freedom, 4 (13%) achieved ≥90% seizure reduction, 13 (41%) had ≥50% reduction, 8 (25%) had <50% reduction, and 5 (16%) experienced no improvement. The average follow-up duration was 1.7 yr (median 1.8 yr, range 0.3-4.8 yr). There was no statistically significant difference for seizure reduction and complications between children and young adults in our cohort or between our cohort and the adult literature.CONCLUSIONThese preliminary data suggest that RNS is well tolerated and an effective off-label surgical treatment of drug-resistant epilepsy in carefully selected pediatric patients as young as 3 yr of age. Data regarding long-term efficacy and safety in children will be critical to optimize patient selection. Open in a separate windowGraphical Abstract

Journal of neurosurgery, Mar 1, 2021

E pilEpsy is a common condition in adult and pediatric patients, affecting at least 50 million pe... more E pilEpsy is a common condition in adult and pediatric patients, affecting at least 50 million people worldwide. 1-3 Unfortunately, approximately 20%-40% of patients with epilepsy continue to have seizures despite appropriate antiepileptic drug therapy. 4-8 These patients often undergo extensive noninvasive workups, including MRI, scalp electroencephalography (EEG), video-EEG, PET, magnetoencephalography, and SPECT, 9,10 without precise localization of the epileptogenic zone (EZ). The EZ is often defined as the "minimum amount of cortex that must be resected (inactivated or completely disconnected) to produce seizure freedom." 11 When noninvasive imaging modalities fail to localize the EZ, invasive modalities such as stereotactic EEG (SEEG) or subdural grid placement are commonly used. 12 SEEG first became popularized in France in the 1950s by Talairach and colleagues 13 and has since been refined using newer stereotactic techniques, including surgical robots. 14-20 Current SEEG systems rely on an anchor bolt, also known as a guide screw or bolt to hold each electrode in place and

Cureus, Dec 2, 2019

Pseudoaneurysms of the thyrocervical trunk and its branches are commonly iatrogenic in nature; ho... more Pseudoaneurysms of the thyrocervical trunk and its branches are commonly iatrogenic in nature; however, trauma is often an inciting mechanism. Open surgical repair was considered the main treatment modality until recent advances in endovascular therapy proved to be a viable treatment option. We report a case of a traumatic pseudoaneurysm arising from the ascending cervical artery with an associated arteriovenous fistula (AVF) that was treated using n-butyl cyanoacrylate (NBCA) embolization. The use of a liquid embolysate such as NBCA provided an efficient and effective means of achieving both pseudoaneurysm occlusion and AVF disconnection.

Neurosurgery, 2021

BACKGROUND Despite the well-documented utility of responsive neurostimulation (RNS, NeuroPace) in... more BACKGROUND Despite the well-documented utility of responsive neurostimulation (RNS, NeuroPace) in adult epilepsy patients, literature on the use of RNS in children is limited. OBJECTIVE To determine the real-world efficacy and safety of RNS in pediatric epilepsy patients. METHODS Patients with childhood-onset drug-resistant epilepsy treated with RNS were retrospectively identified at 5 pediatric centers. Reduction of disabling seizures and complications were evaluated for children (<18 yr) and young adults (>18 yr) and compared with prior literature pertaining to adult patients. RESULTS Of 35 patients identified, 17 were <18 yr at the time of RNS implantation, including a 3-yr-old patient. Four patients (11%) had concurrent resection. Three complications, requiring additional surgical interventions, were noted in young adults (2 infections [6%] and 1 lead fracture [3%]). No complications were noted in children. Among the 32 patients with continued therapy, 2 (6%) achieved s...

Background: Pre-aneurysmal internal carotid steno-occlusive disease resulting in cerebral intra-a... more Background: Pre-aneurysmal internal carotid steno-occlusive disease resulting in cerebral intra-aneurysmal thrombosis and subsequent embolic infarction has not been previously described. Conclusion: Antithrombotic treatment for dissolution of the thrombus and pre-aneurysmal stent angioplasty followed by Pipeline embolization flow diverter placement through the aneurysm is a safe and feasible management option.

Journal of Neurosurgery: Pediatrics

OBJECTIVEStereotactic electroencephalography (SEEG) is an increasingly common technique that neur... more OBJECTIVEStereotactic electroencephalography (SEEG) is an increasingly common technique that neurosurgeons use to help identify the epileptogenic zone. The anchor bolt, which typically secures the electrode to the skull, can be problematic in very thin bone or in electrodes placed in the occiput.METHODSA technique is described to place electrodes without the use of an anchor bolt. Accuracy data for entry point, target point, and depth were collected and compared between electrodes placed with and those placed without an anchor bolt.RESULTSA total of 58 patients underwent placement of 793 electrodes, of which 25 were boltless. The mean entry and depth errors at target were equivalent, although there was a trend toward greater depth error with boltless electrodes (3.4 mm vs 2.01 mm and 2.59 mm in the bolted groups, respectively). The mean lateral target error was slightly but significantly smaller for boltless electrodes. The majority (60%) of boltless leads were placed into thin temp...

Cureus, Dec 2, 2019

Pseudoaneurysms of the thyrocervical trunk and its branches are commonly iatrogenic in nature; ho... more Pseudoaneurysms of the thyrocervical trunk and its branches are commonly iatrogenic in nature; however, trauma is often an inciting mechanism. Open surgical repair was considered the main treatment modality until recent advances in endovascular therapy proved to be a viable treatment option. We report a case of a traumatic pseudoaneurysm arising from the ascending cervical artery with an associated arteriovenous fistula (AVF) that was treated using n-butyl cyanoacrylate (NBCA) embolization. The use of a liquid embolysate such as NBCA provided an efficient and effective means of achieving both pseudoaneurysm occlusion and AVF disconnection.

Cureus, Apr 15, 2020

Endovascular stenting and balloon angioplasty is a feasible although controversial option for int... more Endovascular stenting and balloon angioplasty is a feasible although controversial option for intracranial atherosclerotic stenosis refractory to maximize medical management. High rates of symptomatic in-stent restenosis (ISR) have been identified with Wingspan stent (Stryker, Fremont, CA, USA) placement. Revascularization of ISR by way of re-stenting is often attempted, albeit with high risk and low durability. In lesions with long-segment non-focal critical or emergent occluded stenosis, re-stenting with a single balloon mounted stent is not possible due to deliverability of a lengthy device through a tortuous carotid siphon. Tandem drug-eluting stent placement within the middle cerebral artery to address acute, occlusive ISR using a Wingspan stent, with additional stent reconstruction, has not been previously described.

World Neurosurgery

BACKGROUND De novo formation of arteriovenous malformations (AVMs) and arteriovenous fistulas (AV... more BACKGROUND De novo formation of arteriovenous malformations (AVMs) and arteriovenous fistulas (AVFs) are increasingly being reported in the neurosurgical literature, challenging the notion that AVMs are congenital in origin. Most of this literature centers around the pediatric population. After treatment of an AVM or AVF, recurrence, if any, appears to occur locally to the original insult. We present, to our knowledge, the first case of a de novo direct arteriovenous fistula involving an anterior communicating artery aneurysm in a remote site from a prior ruptured AVM in a pediatric patient. CASE DESCRIPTION We present a case of a 14-year-old female who presented two years prior with an intraparenchymal hemorrhage secondary to a left parietal arteriovenous malformation. That AVM was successfully microsurgically resected and revealed complete angiographic obliteration on postoperative and surveillance angiograms. This patient now presents with a spontaneous intraventricular hemorrhage secondary to a ruptured anterior communicating artery complex aneurysm with a fistulous connection from this aneurysm to the inferior petrosal sinus. The aneurysm and direct arteriovenous fistula were not identified on prior surveillance imaging, indicating de novo formation in a remote site from her prior AVM. CONCLUSION This case highlights the importance of long term imaging surveillance in patients with AVMs. Further prospective studies are indicated to evaluate the long term imaging surveillance necessary to detect early recurrence; thereby, allowing institute earlier definitive treatment. The exact pathophysiology behind these lesions is not fully understood; however, this case lends support to an acquired etiology to vascular malformations.

This retrospective cohort study aimed to explore the study institution’s intraoperative ketamine ... more This retrospective cohort study aimed to explore the study institution’s intraoperative ketamine use during kyphoplasty and compare narcotic requirements in patients who received intraoperative ketamine with those who did not. The authors hypothesized that a single dose of ketamine during kyphoplasty would reduce postoperative narcotic consumption. Included patients underwent kyphoplasty under monitored anesthesia care between 2012 and 2013. Excluded patients were younger than 18 years or had general anesthesia, endotracheal intubation, or major intraoperative complications. Narcotics were converted into morphine equivalents for comparison. Analysis included c2, correlation analyses, multivariate regression analysis, and analysis of variance. Overall, 279 patients were included. Men were a minority of the sample, 26.2% (73/279). More than 83% of patients were ASA class 3 (232/279), and more than 50% repaired a single vertebra (154/279). A single dose of ketamine was administered in ...

Cureus, Apr 15, 2020

Endovascular stenting and balloon angioplasty is a feasible although controversial option for int... more Endovascular stenting and balloon angioplasty is a feasible although controversial option for intracranial atherosclerotic stenosis refractory to maximize medical management. High rates of symptomatic in-stent restenosis (ISR) have been identified with Wingspan stent (Stryker, Fremont, CA, USA) placement. Revascularization of ISR by way of re-stenting is often attempted, albeit with high risk and low durability. In lesions with long-segment non-focal critical or emergent occluded stenosis, re-stenting with a single balloon mounted stent is not possible due to deliverability of a lengthy device through a tortuous carotid siphon. Tandem drug-eluting stent placement within the middle cerebral artery to address acute, occlusive ISR using a Wingspan stent, with additional stent reconstruction, has not been previously described.

Neurosurgery, Sep 15, 2021

BACKGROUNDDespite the well-documented utility of responsive neurostimulation (RNS, NeuroPace) in ... more BACKGROUNDDespite the well-documented utility of responsive neurostimulation (RNS, NeuroPace) in adult epilepsy patients, literature on the use of RNS in children is limited.OBJECTIVETo determine the real-world efficacy and safety of RNS in pediatric epilepsy patients.METHODSPatients with childhood-onset drug-resistant epilepsy treated with RNS were retrospectively identified at 5 pediatric centers. Reduction of disabling seizures and complications were evaluated for children (<18 yr) and young adults (>18 yr) and compared with prior literature pertaining to adult patients.RESULTSOf 35 patients identified, 17 were <18 yr at the time of RNS implantation, including a 3-yr-old patient. Four patients (11%) had concurrent resection. Three complications, requiring additional surgical interventions, were noted in young adults (2 infections [6%] and 1 lead fracture [3%]). No complications were noted in children. Among the 32 patients with continued therapy, 2 (6%) achieved seizure freedom, 4 (13%) achieved ≥90% seizure reduction, 13 (41%) had ≥50% reduction, 8 (25%) had <50% reduction, and 5 (16%) experienced no improvement. The average follow-up duration was 1.7 yr (median 1.8 yr, range 0.3-4.8 yr). There was no statistically significant difference for seizure reduction and complications between children and young adults in our cohort or between our cohort and the adult literature.CONCLUSIONThese preliminary data suggest that RNS is well tolerated and an effective off-label surgical treatment of drug-resistant epilepsy in carefully selected pediatric patients as young as 3 yr of age. Data regarding long-term efficacy and safety in children will be critical to optimize patient selection. Open in a separate windowGraphical Abstract

Journal of neurosurgery, Mar 1, 2021

E pilEpsy is a common condition in adult and pediatric patients, affecting at least 50 million pe... more E pilEpsy is a common condition in adult and pediatric patients, affecting at least 50 million people worldwide. 1-3 Unfortunately, approximately 20%-40% of patients with epilepsy continue to have seizures despite appropriate antiepileptic drug therapy. 4-8 These patients often undergo extensive noninvasive workups, including MRI, scalp electroencephalography (EEG), video-EEG, PET, magnetoencephalography, and SPECT, 9,10 without precise localization of the epileptogenic zone (EZ). The EZ is often defined as the "minimum amount of cortex that must be resected (inactivated or completely disconnected) to produce seizure freedom." 11 When noninvasive imaging modalities fail to localize the EZ, invasive modalities such as stereotactic EEG (SEEG) or subdural grid placement are commonly used. 12 SEEG first became popularized in France in the 1950s by Talairach and colleagues 13 and has since been refined using newer stereotactic techniques, including surgical robots. 14-20 Current SEEG systems rely on an anchor bolt, also known as a guide screw or bolt to hold each electrode in place and

Cureus, Dec 2, 2019

Pseudoaneurysms of the thyrocervical trunk and its branches are commonly iatrogenic in nature; ho... more Pseudoaneurysms of the thyrocervical trunk and its branches are commonly iatrogenic in nature; however, trauma is often an inciting mechanism. Open surgical repair was considered the main treatment modality until recent advances in endovascular therapy proved to be a viable treatment option. We report a case of a traumatic pseudoaneurysm arising from the ascending cervical artery with an associated arteriovenous fistula (AVF) that was treated using n-butyl cyanoacrylate (NBCA) embolization. The use of a liquid embolysate such as NBCA provided an efficient and effective means of achieving both pseudoaneurysm occlusion and AVF disconnection.

Neurosurgery, 2021

BACKGROUND Despite the well-documented utility of responsive neurostimulation (RNS, NeuroPace) in... more BACKGROUND Despite the well-documented utility of responsive neurostimulation (RNS, NeuroPace) in adult epilepsy patients, literature on the use of RNS in children is limited. OBJECTIVE To determine the real-world efficacy and safety of RNS in pediatric epilepsy patients. METHODS Patients with childhood-onset drug-resistant epilepsy treated with RNS were retrospectively identified at 5 pediatric centers. Reduction of disabling seizures and complications were evaluated for children (<18 yr) and young adults (>18 yr) and compared with prior literature pertaining to adult patients. RESULTS Of 35 patients identified, 17 were <18 yr at the time of RNS implantation, including a 3-yr-old patient. Four patients (11%) had concurrent resection. Three complications, requiring additional surgical interventions, were noted in young adults (2 infections [6%] and 1 lead fracture [3%]). No complications were noted in children. Among the 32 patients with continued therapy, 2 (6%) achieved s...

Background: Pre-aneurysmal internal carotid steno-occlusive disease resulting in cerebral intra-a... more Background: Pre-aneurysmal internal carotid steno-occlusive disease resulting in cerebral intra-aneurysmal thrombosis and subsequent embolic infarction has not been previously described. Conclusion: Antithrombotic treatment for dissolution of the thrombus and pre-aneurysmal stent angioplasty followed by Pipeline embolization flow diverter placement through the aneurysm is a safe and feasible management option.

Journal of Neurosurgery: Pediatrics

OBJECTIVEStereotactic electroencephalography (SEEG) is an increasingly common technique that neur... more OBJECTIVEStereotactic electroencephalography (SEEG) is an increasingly common technique that neurosurgeons use to help identify the epileptogenic zone. The anchor bolt, which typically secures the electrode to the skull, can be problematic in very thin bone or in electrodes placed in the occiput.METHODSA technique is described to place electrodes without the use of an anchor bolt. Accuracy data for entry point, target point, and depth were collected and compared between electrodes placed with and those placed without an anchor bolt.RESULTSA total of 58 patients underwent placement of 793 electrodes, of which 25 were boltless. The mean entry and depth errors at target were equivalent, although there was a trend toward greater depth error with boltless electrodes (3.4 mm vs 2.01 mm and 2.59 mm in the bolted groups, respectively). The mean lateral target error was slightly but significantly smaller for boltless electrodes. The majority (60%) of boltless leads were placed into thin temp...

Cureus, Dec 2, 2019

Pseudoaneurysms of the thyrocervical trunk and its branches are commonly iatrogenic in nature; ho... more Pseudoaneurysms of the thyrocervical trunk and its branches are commonly iatrogenic in nature; however, trauma is often an inciting mechanism. Open surgical repair was considered the main treatment modality until recent advances in endovascular therapy proved to be a viable treatment option. We report a case of a traumatic pseudoaneurysm arising from the ascending cervical artery with an associated arteriovenous fistula (AVF) that was treated using n-butyl cyanoacrylate (NBCA) embolization. The use of a liquid embolysate such as NBCA provided an efficient and effective means of achieving both pseudoaneurysm occlusion and AVF disconnection.

Cureus, Apr 15, 2020

Endovascular stenting and balloon angioplasty is a feasible although controversial option for int... more Endovascular stenting and balloon angioplasty is a feasible although controversial option for intracranial atherosclerotic stenosis refractory to maximize medical management. High rates of symptomatic in-stent restenosis (ISR) have been identified with Wingspan stent (Stryker, Fremont, CA, USA) placement. Revascularization of ISR by way of re-stenting is often attempted, albeit with high risk and low durability. In lesions with long-segment non-focal critical or emergent occluded stenosis, re-stenting with a single balloon mounted stent is not possible due to deliverability of a lengthy device through a tortuous carotid siphon. Tandem drug-eluting stent placement within the middle cerebral artery to address acute, occlusive ISR using a Wingspan stent, with additional stent reconstruction, has not been previously described.

World Neurosurgery

BACKGROUND De novo formation of arteriovenous malformations (AVMs) and arteriovenous fistulas (AV... more BACKGROUND De novo formation of arteriovenous malformations (AVMs) and arteriovenous fistulas (AVFs) are increasingly being reported in the neurosurgical literature, challenging the notion that AVMs are congenital in origin. Most of this literature centers around the pediatric population. After treatment of an AVM or AVF, recurrence, if any, appears to occur locally to the original insult. We present, to our knowledge, the first case of a de novo direct arteriovenous fistula involving an anterior communicating artery aneurysm in a remote site from a prior ruptured AVM in a pediatric patient. CASE DESCRIPTION We present a case of a 14-year-old female who presented two years prior with an intraparenchymal hemorrhage secondary to a left parietal arteriovenous malformation. That AVM was successfully microsurgically resected and revealed complete angiographic obliteration on postoperative and surveillance angiograms. This patient now presents with a spontaneous intraventricular hemorrhage secondary to a ruptured anterior communicating artery complex aneurysm with a fistulous connection from this aneurysm to the inferior petrosal sinus. The aneurysm and direct arteriovenous fistula were not identified on prior surveillance imaging, indicating de novo formation in a remote site from her prior AVM. CONCLUSION This case highlights the importance of long term imaging surveillance in patients with AVMs. Further prospective studies are indicated to evaluate the long term imaging surveillance necessary to detect early recurrence; thereby, allowing institute earlier definitive treatment. The exact pathophysiology behind these lesions is not fully understood; however, this case lends support to an acquired etiology to vascular malformations.

This retrospective cohort study aimed to explore the study institution’s intraoperative ketamine ... more This retrospective cohort study aimed to explore the study institution’s intraoperative ketamine use during kyphoplasty and compare narcotic requirements in patients who received intraoperative ketamine with those who did not. The authors hypothesized that a single dose of ketamine during kyphoplasty would reduce postoperative narcotic consumption. Included patients underwent kyphoplasty under monitored anesthesia care between 2012 and 2013. Excluded patients were younger than 18 years or had general anesthesia, endotracheal intubation, or major intraoperative complications. Narcotics were converted into morphine equivalents for comparison. Analysis included c2, correlation analyses, multivariate regression analysis, and analysis of variance. Overall, 279 patients were included. Men were a minority of the sample, 26.2% (73/279). More than 83% of patients were ASA class 3 (232/279), and more than 50% repaired a single vertebra (154/279). A single dose of ketamine was administered in ...