Mark M. Souweidane, Caitlin E. Hoffman and Theodore H. Schwartz
Intraventricular anatomy has been detailed as it pertains to endoscopic surgery within the third ventricle, particularly for performing endoscopic third ventriculostomy (ETV) and endoscopic colloid cyst resection. The expanding role of endoscopic surgery warrants a careful appraisal of these techniques as they relate to frequent anatomical variants. Given the common occurrence of cavum septum pellucidum (CSP) and cavum vergae (CV), the endoscopic surgeon should be familiar with that particular anatomy especially as it pertains to surgery within the third ventricle.
From a prospective database of endoscopic surgical cases were selected those cases in which the defined pathology necessitated surgery within the third ventricle and there was coexistent CSP and CV. Pertinent radiographic studies, operative notes, and archived video files were reviewed to define the relevant anatomy. Features of the intracavitary anatomy were assessed regarding their importance in approaching the third ventricle.
Four cases involving endoscopic surgery within the third ventricle (2 colloid cyst resections and 2 ETVs) were identified in which the surgical objective was accomplished through a septal cavum. In each case the width of the body of the lateral ventricle was reduced and the foramen of Monro was obscured. Because of the ventricular distortion, a stereotactic transcavum route was used for approaching the third ventricle. Entry into the third ventricle was accomplished through an interforniceal fenestration immediately behind the anterior commissure. The surgical goal was met in each case without any neurological change or postoperative morbidity. During the follow-up period, there has been no recurrence of a colloid cyst and no need of a secondary cerebrospinal fluid diversionary procedure.
In the presence of a CSP and CV, endoscopic navigation into the third ventricle can be problematic via a transforaminal approach. Alternatively, a transcavum interforniceal route for endoscopic surgery in the third ventricle is suggested, with the rostral lamina and the anterior commissure as important anatomical landmarks. Endoscopic third ventriculostomy and endoscopic colloid cyst resection performed via a transcavum interforniceal route in patients with a coexistent septal cavum is a feasible and safe option.
Caitlin E. Hoffman, Alejandro Santillan, Lauren Rotman, Y. Pierre Gobin and Mark M. Souweidane
The therapeutic potential for cerebral angiography (CA) in young children is expanding. However, its use in this patient population is limited by presumed higher complication rates among children. Therefore, to improve the accuracy of counseling of the parents/guardians of these patients and to identify modifiable risk factors, the authors evaluated complications after CA in young children.
The authors reviewed data for 309 consecutive cerebral angiograms obtained in 87 children younger than 36 months of age from 2004 to 2010 at a single institution. They analyzed demographics, diagnosis, angiographic findings, and complications.
The patient population comprised 40 boys and 47 girls; mean age was 14.36 months (range 1–36 months) and mean weight was 10.8 kg (range 3.7–21.0 kg). For 292 of the 309 procedures, intraarterial chemotherapy was administered; the remaining 17 procedures were for vascular malformations, stroke, tumor embolization, and intracranial hemorrhage. The rate of neurological complications was 0.0%. The rate of nonneurological complications was 2.9%: 7 cases of contrast allergy or bronchospasm, 1 groin hematoma (body weight 7 kg), and 1 transient femoral artery occlusion (body weight 10.8 kg). The rate of radiographic complications was 1.3%: 1 case of transient asymptomatic intraarterial dissection and 3 cases of asymptomatic vasospasm. Postprocedural MRI was performed for 33.3% of patients with no evidence of ischemia. There were no delayed complications. Mean follow-up time was 16.6 months. No association was found between complications and age, duration of anesthesia, number of vessels catheterized, size of the sheath, or diagnostic versus interventional procedures. Despite a trend toward a higher rate of complications for patients who weighed less than 15 kg, this finding was not significant (p = 0.35).
The rate of complications for CA in young children is comparable to rates reported for older children and lower than rates reported for adults. When appropriately indicated, CA should not be omitted from the therapeutic strategy of children younger than 36 months of age.
Whitney E. Parker, Elizabeth K. Weidman, J. Levi Chazen, Sumit N. Niogi, Rafael Uribe-Cardenas, Michael G. Kaplitt and Caitlin E. Hoffman
The authors tested the feasibility of magnetic resonance–guided focused ultrasound (MRgFUS) ablation of mesial temporal lobe epilepsy (MTLE) seizure circuits. Up to one-third of patients with mesial temporal sclerosis (MTS) suffer from medically refractory epilepsy requiring surgery. Because current options such as open resection, laser ablation, and Gamma Knife radiosurgery pose potential risks, such as infection, hemorrhage, and ionizing radiation, and because they often produce visual or neuropsychological deficits, the authors developed a noninvasive MRgFUS ablation strategy for mesial temporal disconnection to mitigate these risks.
The authors retrospectively reviewed 3-T MRI scans obtained with diffusion tensor imaging (DTI). The study group included 10 patients with essential tremor (ET) who underwent pretreatment CT and MRI prior to MRgFUS, and 2 patients with MTS who underwent MRI. Fiber tracking of the fornix-fimbria pathway and inferior optic radiations was performed, ablation sites mimicking targets of open posterior hippocampal disconnection were modeled, and theoretical MRgFUS surgical plans were devised. Distances between the targets and optic radiations were measured, helmet angulations were prescribed, and the numbers of available MRgFUS array elements were calculated.
Tractograms of fornix-fimbria and optic radiations were generated in all ET and MTS patients successfully. Of the 10 patients with both the CT and MRI data necessary for the analysis, 8 patients had adequate elements available to target the ablation site. A margin (mean 8.5 mm, range 6.5–9.8 mm) of separation was maintained between the target lesion and optic radiations.
MRgFUS offers a noninvasive option for seizure tract disruption. DTI identifies fornix-fimbria and optic radiations to localize optimal ablation targets and critical surrounding structures, minimizing risk of postoperative visual field deficits. This theoretical modeling study provides the necessary groundwork for future clinical trials to apply this novel neurosurgical technique to patients with refractory MTLE and surgical contraindications, multiple prior surgeries, or other factors favoring noninvasive treatment.
Peter F. Morgenstern, Caitlin E. Hoffman, Gary Kocharian, Ranjodh Singh, Philip E. Stieg and Mark M. Souweidane
The optimal method for detecting recurrent arteriovenous malformations (AVMs) in children is unknown. An inherent preference exists for MR angiography (MRA) surveillance rather than arteriography. The validity of this strategy is uncertain.
A retrospective chart review was performed on pediatric patients treated for cerebral AVMs at a single institution from 1998 to 2012. Patients with complete obliteration of the AVM nidus after treatment and more than 12 months of follow-up were included in the analysis. Data collection focused on recurrence rates, associated risk factors, and surveillance methods.
A total of 45 patients with a mean age of 11.7 years (range 0.5–18 years) were treated for AVMs via surgical, endovascular, radiosurgical, or combined approaches. Total AVM obliteration on posttreatment digital subtraction angiography (DSA) was confirmed in 27 patients, of whom the 20 with more than 12 months of follow-up were included in subsequent analysis. The mean follow-up duration in this cohort was 5.75 years (median 5.53 years, range 1.11–10.64 years). Recurrence occurred in 3 of 20 patients (15%). Two recurrences were detected by surveillance DSA and 1 at the time of rehemorrhage. No recurrences were detected by MRA. Median time to recurrence was 33.6 months (range 19–71 months). Two patients (10%) underwent follow-up DSA, 5 (25%) had DSA and MRI/MRA, 9 (45%) had MRI/MRA only, 1 (5%) had CT angiography only, and 3 (15%) had no imaging within the first 3 years of follow-up. After 5 years posttreatment, 2 patients (10%) were followed with MRI/MRA only, 2 (10%) with DSA only, and 10 (50%) with continued DSA and MRI/MRA.
AVM recurrence in children occurred at a median of 33.6 months, when MRA was more commonly used for surveillance, but failed to detect any recurrences. A recurrence rate of 15% may be an underestimate given the reliance on surveillance MRA over angiography. A new surveillance strategy is proposed, taking into account exposure to diagnostic radiation and the potential for catastrophic rehemorrhage.
Caitlin Hoffman, Melissa Yuan, Andre E. Boyke, Ashley O’Connor, Therese Haussner, Imali Perera and Mark Souweidane
In recent years, the Weill Cornell neurosurgical team noticed an increase in referrals for plagiocephaly, likely due to increased infant back-sleeping and awareness. A plagiocephaly clinic staffed by a nurse practitioner and a physician assistant was established in 2016 to meet this demand, and to decrease the nonsurgical case burden on neurosurgeons. The purpose of this study was to examine the impact of a clinic directed by advanced nonphysician practice providers (NPPs) on parental satisfaction and nonsurgical work hours for staff neurosurgeons.
Over a 1.5-year period (from January 1, 2016, to June 20, 2017), Likert scale–based surveys were administered to parents before and after their child’s visit to the NPP-staffed clinic. Clinic hours were tracked to assess impact on the neurosurgeon’s workload.
All 185 patients seen in the plagiocephaly clinic over the 1.5-year period completed pre- and postvisit surveys. Parents all reported a significant reduction in their level of concern for their child’s diagnosis after the evaluation, and 95.5% were “very likely” to recommend the clinic. All parents felt that there was an increase in their knowledge base after an appointment with an NPP. Additionally, over 1 year in the study, 170 visits to the NPP plagiocephaly clinic were recorded, resulting in 85 hours that neurosurgeons normally would have spent in the clinic that they now were able to spend in the operating room.
This research provides evidence that an NPP-directed clinic can positively impact parental satisfaction and decrease nonsurgical case burden on neurosurgeons.
Rafael Uribe-Cardenas, Andre E. Boyke, Justin T. Schwarz, Peter F. Morgenstern, Jeffrey P. Greenfield, Theodore H. Schwartz, James T. Rutka, James Drake and Caitlin E. Hoffman
Early surgical intervention for pediatric refractory epilepsy is increasingly advocated as surgery has become safer and data have demonstrated improved outcomes with early seizure control. There is concern that the risks associated with staged invasive electroencephalography (EEG) in very young children outweigh the potential benefits. Here, the authors present a cohort of children with refractory epilepsy who were referred for invasive monitoring, and they evaluate the role and safety of staged invasive EEG in those 3 years old and younger.
The authors conducted a retrospective review of children 3 years and younger with epilepsy, who had been managed surgically at two institutions between 2001 and 2015. A cohort of pediatric patients older than 3 years of age was used for comparison. Demographics, seizure etiology, surgical management, surgical complications, and adverse events were recorded. Statistical analysis was completed using Stata version 13. A p < 0.05 was considered statistically significant. Fisher’s exact test was used to compare proportions.
Ninety-four patients (45 patients aged ≤ 3 [47.9%]) and 208 procedures were included for analysis. Eighty-six procedures (41.3%) were performed in children younger than 3 years versus 122 in the older cohort (58.7%). Forty-two patients underwent grid placement (14 patients aged ≤ 3 [33.3%]); 3 of them developed complications associated with the implant (3/42 [7.14%]), none of whom were among the younger cohort. Across all procedures, 11 complications occurred in the younger cohort versus 5 in the older patients (11/86 [12.8%] vs 5/122 [4.1%], p = 0.032). Two adverse events occurred in the younger group versus 1 in the older group (2/86 [2.32%] vs 1/122 [0.82%], p = 0.571). Following grid placement, 13/14 younger patients underwent guided resections compared to 20/28 older patients (92.9% vs 71.4%, p = 0.23).
While overall complication rates were higher in the younger cohort, subdural grid placement was not associated with an increased risk of surgical complications in that population. Invasive electrocorticography informs management in very young children with refractory, localization-related epilepsy and should therefore be used when clinically indicated.
James M. Drake and Jay Riva-Cambrin