Outcomes of laparoscopic and open ventriculoperitoneal shunt placement.

OBJECTIVE: Ventriculoperitoneal (VP) shunt placement requires a concurrent abdominal procedure. For peritoneal access laparoscopic or open approach may be utilized. Our aim was to compare patient/procedure characteristics and outcomes by peritoneal approach for VP shunts in children. METHODS: NSQIP-Pediatric procedure targeted cerebral spinal fluid shunt Participant Use Data Files from 2016 to 2020 were queried. Patients were grouped into laparoscopic vs open abdominal approach. Patient demographics, procedure characteristics and 30-day outcomes were compared. RESULTS: 7742 NSQIP-Pediatric patients underwent VP shunt placement. Patients undergoing laparoscopic approach were older and required less preoperative support. Mean operative time was longer with laparoscopy (mean(SD): 74.2(48.1) vs. 64.6(39) minutes, p â€‹< â€‹0.0001) but had shorter hospital LOS. There was no difference in SSI, readmissions, or reoperation rates. CONCLUSION: Patients undergoing laparoscopy for distal VP shunts are older with less support needs preoperatively. While laparoscopic approach had a shorter hospital LOS, there was no demonstratable difference in SSI, readmissions or reoperations between approaches. Further studies are needed to assess long-term outcomes.

Direct withdrawal of a retained foreign body bisecting the thoracic spinal canal in a neurologically intact pediatric patient: illustrative case.

BACKGROUND: Nonmissile penetrating spinal cord injury (NMPSCI) with a retained foreign body (RFB) is rare and usually results in permanent neurological deficits. In extremely rare cases, patients can present without significant neurological deficits despite an RFB that traverses the spinal canal. Given the rarity of these cases, a consensus has not yet been reached on optimal management. In a patient with an RFB and a neurologically normal clinical examination, the risk of open surgical exploration may outweigh the benefit and direct withdrawal may be a better option. OBSERVATIONS: A 10-year-old female suffered an NMPSCI to the thoracic spine with an RFB that bisected the spinal canal but remained neurologically intact. Direct withdrawal of the RFB was chosen instead of open surgical exploration, leading to an excellent clinical outcome. The literature was reviewed to find other examples of thoracic NMPSCI with RFB and neurologically normal examinations. Management strategies were compared. LESSONS: For NMPSCI with RFB and without significant neurological deficits, direct withdrawal is a viable and possibly the best treatment option. The use of fast-acting anesthesia without intubation minimizes patient manipulation, speeds up recovery, and allows early assessment of neurological status after removal.

Endovascular treatment of pediatric basilar artery aneurysms: case series and literature review.

PURPOSE: Pediatric basilar artery aneurysms are rare and challenging to treat. Microsurgical options and standard endovascular coiling are often undesirable choices for treatment of this pathology. Additional endovascular strategies are needed. METHODS: Presentation, diagnosis, and management of pediatric basilar aneurysms were reviewed, with an emphasis on endovascular treatment strategies. Our case series of 2 patients was presented in detail, one treated with flow diversion and vessel sacrifice and one treated with stent-assisted coiling. An extensive review of the literation was performed to find other examples of pediatric basilar artery aneurysms treated with endovascular techniques. RESULTS: Twenty-nine studies met inclusion criteria. Fifty-nine aneurysms in 58 patients were treated using endovascular techniques. Mortality rate was 10.3% (6/58) and a poor outcome (GOS 1-3) occurred in 15.5% (9/58). There were 4 reported recurrences requiring retreatment; however, only 46.5% of patients had reported follow-up of at least 1 year. 71.1% (42/59) were dissecting aneurysms. CONCLUSION: Basilar artery aneurysms in the pediatric population are rare, commonly giant and fusiform, and often not amenable to microsurgical or coiling techniques. The surrounding vasculature, location, size, and morphology of the aneurysm along with the durability of treatment must be considered in treatment decisions. With proper patient selection, stent-assisted coiling and flow diversion may increase the durability and safety of endovascular treatment in this population.

Occipital interhemispheric transtentorial approach in pediatric patients for lesions of the superomedial cerebellum: operative findings and results.

BACKGROUND: The occipital interhemispheric transtentorial (OITT) approach is frequently used for accessing the pineal region. There are scarce reports of using the OITT to access superior cerebellar lesions. This approach affords the patient several advantages over traditional posterior fossa approaches. PURPOSE: This study is to describe and evaluate clinical outcomes in a single surgeon case series of the OITT approach for pediatric patients with lesions of the superior cerebellum. METHODS: All pediatric patients who underwent an OITT craniotomy for a superior cerebellar lesion by a single surgeon over a 5-year period were included in this retrospective analysis. Patient demographics and clinical data were collected. RESULTS: Thirteen pediatric patients were identified. Cases included twelve tumors and one arteriovenous malformation. Gross total resection was achieved in 92% of cases. No patients developed posterior fossa syndrome. Two patients had transient homonymous hemianopsia that resolved by 1 month post-operatively. There were no permanent neurological deficits. CONCLUSION: For superomedial cerebellar lesions presenting to the tentorial surface of the superior cerebellum in patients with normal to steep tentorial angles, the OITT approach is effective and safe. This approach has a low risk of posterior fossa syndrome and permanent visual deficits when applied appropriately. Patient selection is critical for maximizing the advantages of the OITT for superior cerebellar lesions.

Endoscopic Third Ventriculostomy and Endoscopic Intracranial Cyst Fenestration in an Outpatient Ambulatory Surgery Center Yields Reduced Cost But Equal Efficacy and Safety Compared with Surgery in the Hospital.

BACKGROUND: A transition is underway in neurosurgery to perform relatively safe surgeries outpatient, often at ambulatory surgery centers (ASC). We sought to evaluate whether simple intracranial endoscopic procedures such as third ventriculostomy and cyst fenestration can be safely and effectively performed at an ASC, while comparing costs with the hospital. METHODS: A retrospective chart review was performed for patients who underwent elective intracranial neuroendoscopic (NE) intervention at either a quaternary hospital or an affiliated ASC between August 2014 and September 2017. Groups were compared on length of stay, perioperative and 30-day morbidity, as well as clinical outcome at last follow-up. The total cost for these procedures were compared in relative units between all ASC cases and a small subset of hospital cases. RESULTS: In total, 16 NE operations performed at the ASC (mean patient age 29.8 years) and 37 at the hospital (mean age 15.4 years) with average length of stay of 3.5 hours and 23.1 hours respectively (P < 0.05). There were no acute complications in either cohort or morbid events requiring hospitalization within 30 days. Surgical success was noted for 75% of the ASC patients and 73% of the hospital cohort. The mean cost of 5 randomly selected hospital operations with same-day discharge and 5 with overnight stay was 3.4 and 4.1 times that of the ASC cohort, respectively (P < 0.05). CONCLUSIONS: Elective endoscopic third ventriculostomy and other simple NE procedures can be safely and effectively performed at an ASC for appropriate patients with significantly reduced cost compared with the hospital.

Orbitozygomatic Craniotomy via an Eyebrow Incision: Management of the Opened Frontal Sinus.

Background The eyebrow orbitozygomatic craniotomy is a minimally invasive approach that can access a wide variety of lesions. Unintentional breach of the frontal sinus frequently occurs and has been cited as a reason to avoid this approach. Lack of access to a large pericranial graft and the inability to completely cranialize the sinus requires alternate techniques of sinus repair. We describe a technique for repairing an opened frontal sinus and retrospectively reviewed complications related to this approach. Methods All patients, who underwent an orbitozygomatic craniotomy via an eyebrow incision by a single surgeon from August 1, 2012 to August 31, 2018, were included in this retrospective analysis. Data were collected on patient demographics, pathology treated, operative details, and perioperative morbidity. Follow-up ranged from 6 weeks to 6 years. Results Total 50 patients with a wide variety of pathologies underwent analysis. Frontal sinus breach occurred in 21 patients. All were repaired by the described technique. One patient (ruptured aneurysm) had a suspected cerebrospinal fluid (CSF) leak postoperatively that resolved without any additional intervention. One patient developed a pneumomeningocele 4 years postoperatively that required reoperation. No patient suffered any infection or delayed CSF leak. Conclusion Breach of the frontal sinus is common during eyebrow craniotomies. Despite reduced options for local repair, these patients have experienced no CSF leaks requiring intervention and no infections in our series. Long-term mucocele risk is not reliably determined with our length of follow-up. Breach of the frontal sinus is not a contraindication to the eyebrow approach.

Delayed Traumatic Tension Pneumocephalus: A Case Report.

BACKGROUND: Traumatic tension pneumocephalus is a rare complication after craniofacial fractures that can cause devastating neurologic deficits if not managed promptly and effectively. CASE REPORT: A 38-year-old man with no past medical history presented to the Emergency Department (ED) after a motor vehicle crash. He was noted to have an open frontal scalp laceration. Computed tomography (CT) revealed a right frontal subdural hematoma and right medial frontal contusion. There was also a frontal bone fracture extending through the frontal sinus with mild underlying pneumocephalus. He was monitored for cerebrospinal fluid (CSF) leak and was subsequently discharged on postinjury day 9. He re-presented to the ED 14 days post injury with lethargy, confusion, headache, and swelling around his scalp laceration. A CT scan was obtained that revealed a large-volume intraparenchymal pneumocephalus (pneumocerebri) with mass effect and midline shift. The patient was started on 100% oxygen and admitted to the intensive care unit. He was taken to the operating room for evacuation of the pneumocerebri, repair of dural defect, placement of a vascularized pericranial graft, and placement of a lumbar drain. His lumbar drain was removed on postoperative day 3 and he was discharged home neurologically intact on postoperative day 6. At 1 month follow-up he had no evidence of CSF leak and was neurologically intact. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: This case is presented to increase awareness among emergency physicians that traumatic tension pneumocephalus, and in this case, pneumocerebri, is a rare life-threatening neurosurgical emergency in patients with severe craniofacial fractures after blunt or penetrating head trauma. Early temporizing measures in the ED, such as 100% oxygen via nonrebreather face mask, and urgent neurosurgical consultation are indicated to prevent neurologic deterioration.

Proptosis, Orbital Pain, and Long-Standing Monocular Vision Loss Resolved by Surgical Resection of Intraosseous Spheno-Orbital Meningioma: A Case Report and Literature Review.

Background and Importance We present a case of a patient with a residual intraosseous sphenoid wing meningioma presenting with proptosis, orbital pain, and monocular vision loss for 8 months who underwent decompression of the optic canal, orbital contents, and orbital reconstruction resulting in significant improvement in her vision loss with full resolution of proptosis and orbital pain. Clinical Presentation A 43-year-old female presented with a 1 year history of headache, peri-orbital pain, proptosis, and severe vision loss. She had previously undergone subtotal resection of a large Simpson Grade 1 spheno-orbital meningioma 3 years prior at an outside institution. Workup at our institution revealed hyperostosis of the left greater wing of the sphenoid bone and narrowing of the optic canal along with bony enhancement concerning for residual tumor. The patient was given the recommendation from outside institutions for radiation, presumably due to the chronicity of her visual loss. Our institution recommended resection of the residual osseous tumor with orbital reconstruction. Less than 2 weeks after surgery, the patient noted significant improvement in orbital pain and vision. At 3 months, she had regained full and symmetric orbital appearance with no orbital pain. Her visual acuity improved to 20/30 with full visual fields. Conclusion Surgical decompression of the optic canal and orbital contents for tumor related sphenoid wing hyperostosis should be strongly considered, despite an extended duration of visual change and loss. This case report shows that vision can be significantly restored even after symptoms have been present for greater than 6 months.

Factors associated with syrinx size in pediatric patients treated for Chiari malformation type I and syringomyelia: a study from the Park-Reeves Syringomyelia Research Consortium.

OBJECTIVE: Factors associated with syrinx size in pediatric patients undergoing posterior fossa decompression (PFD) or PFD with duraplasty (PFDD) for Chiari malformation type I (CM-I) with syringomyelia (SM; CM-I+SM) are not well established. METHODS: Using the Park-Reeves Syringomyelia Research Consortium registry, the authors analyzed variables associated with syrinx radiological outcomes in patients (< 20 years old at the time of surgery) with CM-I+SM undergoing PFD or PFDD. Syrinx resolution was defined as an anteroposterior (AP) diameter of ≤ 2 mm or ≤ 3 mm or a reduction in AP diameter of ≥ 50%. Syrinx regression or progression was defined using 1) change in syrinx AP diameter (≥ 1 mm), or 2) change in syrinx length (craniocaudal, ≥ 1 vertebral level). Syrinx stability was defined as a < 1-mm change in syrinx AP diameter and no change in syrinx length. RESULTS: The authors identified 380 patients with CM-I+SM who underwent PFD or PFDD. Cox proportional hazards modeling revealed younger age at surgery and PFDD as being independently associated with syrinx resolution, defined as a ≤ 2-mm or ≤ 3-mm AP diameter or ≥ 50% reduction in AP diameter. Radiological syrinx resolution was associated with improvement in headache (p < 0.005) and neck pain (p < 0.011) after PFD or PFDD. Next, PFDD (p = 0.005), scoliosis (p = 0.007), and syrinx location across multiple spinal segments (p = 0.001) were associated with syrinx diameter regression, whereas increased preoperative frontal-occipital horn ratio (FOHR; p = 0.007) and syrinx location spanning multiple spinal segments (p = 0.04) were associated with syrinx length regression. Scoliosis (HR 0.38 [95% CI 0.16-0.91], p = 0.03) and smaller syrinx diameter (5.82 ± 3.38 vs 7.86 ± 3.05 mm; HR 0.60 [95% CI 0.34-1.03], p = 0.002) were associated with syrinx diameter stability, whereas shorter preoperative syrinx length (5.75 ± 4.01 vs 9.65 ± 4.31 levels; HR 0.21 [95% CI 0.12-0.38], p = 0.0001) and smaller pB-C2 distance (6.86 ± 1.27 vs 7.18 ± 1.38 mm; HR 1.44 [95% CI 1.02-2.05], p = 0.04) were associated with syrinx length stability. Finally, younger age at surgery (8.19 ± 5.02 vs 10.29 ± 4.25 years; HR 1.89 [95% CI 1.31-3.04], p = 0.01) was associated with syrinx diameter progression, whereas increased postoperative syrinx diameter (6.73 ± 3.64 vs 3.97 ± 3.07 mm; HR 3.10 [95% CI 1.67-5.76], p = 0.003), was associated with syrinx length progression. PFD versus PFDD was not associated with syrinx progression or reoperation rate. CONCLUSIONS: These data suggest that PFDD and age are independently associated with radiological syrinx improvement, although forthcoming results from the PFDD versus PFD randomized controlled trial (NCT02669836, clinicaltrials.gov) will best answer this question.

Converting Pediatric Patients and Young Adults From a Shunt to a Third Ventriculostomy: A Multicenter Evaluation.

BACKGROUND: Endoscopic third ventriculostomy (ETV) is an effective primary treatment for certain forms of hydrocephalus. However, its use in children with an existing shunt is less well known. OBJECTIVE: To report a multicenter experience in attempting to convert patients from shunt dependence to a third ventriculostomy and to determine predictors of success. METHODS: Three participating centers provided retrospectively collected information on patients with an attempted conversion from a shunt to an ETV between December 1, 2008, and April 1, 2018. Demographic, clinical, and radiological data were recorded. Success was defined as shunt independence at the last follow-up. RESULTS: Eighty patients with an existing ventricular shunt underwent an ETV. The median age at the time of the index ETV was 9.9 yr, and 44 (55%) patients were male. The overall success rate was 64% (51/80), with a median duration of follow-up of 2.0 yr (range, 0.1-9.4 yr). Four patients required a successful repeat ETV at a median of 1.7 yr (range, 0.1-5.7 yr) following the index ETV. Only age was predictive of ETV failure on multivariate analysis (odds ratio 0.86 [95% CI 0.78-0.94], P = .005). No patient less than 6 mo of age underwent an ETV, and of the 5 patients between 6 and 12 mo of age, 4 failed. CONCLUSION: Although not every shunted patient will be a candidate for an ETV, nor will they be successfully converted, an ETV should at least be considered in every child who presents with a shunt malfunction or who has an externalized shunt.

Endoscopic management of benign cystic lesions of the thalamus with fenestrated stent placement.

Benign intracranial cystic lesions of the thalamus are an uncommon clinical entity rarely requiring operative decompression. In combination with cyst fenestration, cerebrospinal fluid (CSF) flow diversion or fenestrated stent placement may be performed at the time of surgery. We describe a method of treatment of these cysts using endoscopic cyst fenestration with fenestrated transventricular stent placement. Three patients with benign cystic lesions were treated with stereotactic-guided, endoscopic fenestration and fenestrated stent placement. All 3 had radiographic and clinical improvement. There were no complications. Endoscopic fenestration and transventricular fenestrated stent placement is a minimally invasive, effective, and safe method to decompress benign, symptomatic cystic lesions of the thalamus.

Comparing Preoperative With Postoperative Stereotactic Radiosurgery for Resectable Brain Metastases: A Multi-institutional Analysis.

BACKGROUND: Stereotactic radiosurgery (SRS) is an increasingly common modality used with surgery for resectable brain metastases (BM). OBJECTIVE: To present a multi-institutional retrospective comparison of outcomes and toxicities of preoperative SRS (Pre-SRS) and postoperative SRS (Post-SRS). METHODS: We reviewed the records of patients who underwent resection of BM and either Pre-SRS or Post-SRS alone between 2005 and 2013 at 2 institutions. Pre-SRS used a dose-reduction strategy based on tumor size, with planned resection within 48 hours. Cumulative incidence with competing risks was used to determine estimated rates. RESULTS: A total of 180 patients underwent surgical resection for 189 BM: 66 (36.7%) underwent Pre-SRS and 114 (63.3%) underwent Post-SRS. Baseline patient characteristics were balanced except for higher rates of performance status 0 (62.1% vs 28.9%, P < .001) and primary breast cancer (27.2% vs 10.5%, P = .010) for Pre-SRS. Pre-SRS had lower median planning target volume margin (0 mm vs 2 mm) and peripheral dose (14.5 Gy vs 18 Gy), but similar gross tumor volume (8.3 mL vs 9.2 mL, P = .85). The median imaging follow-up period was 24.6 months for alive patients. Multivariable analyses revealed no difference between groups for overall survival (P = .1), local recurrence (P = .24), and distant brain recurrence (P = .75). Post-SRS was associated with significantly higher rates of leptomeningeal disease (2 years: 16.6% vs 3.2%, P = .010) and symptomatic radiation necrosis (2 years: 16.4% vs 4.9%, P = .010). CONCLUSION: Pre-SRS and Post-SRS for resected BM provide similarly favorable rates of local recurrence, distant brain recurrence, and overall survival, but with significantly lower rates of symptomatic radiation necrosis and leptomeningeal disease in the Pre-SRS cohort. A prospective clinical trial comparing these treatment approaches is warranted. ABBREVIATIONS: BM, brain metastasesCI, confidence intervalCTV, clinical target volumeDBR, distant brain recurrenceGTV, gross tumor volumeLC, local controlLMD, leptomeningeal diseaseLR, local recurrenceMVA, multivariable analysisOS, overall survivalPost-SRS, postoperative stereotactic radiosurgeryPre-SRS, preoperative stereotactic radiosurgeryPTV, planning target volumeRN, radiation necrosisSRN, symptomatic radiation necrosisSRS, stereotactic radiosurgeryWBRT, whole-brain radiation therapy.

Polymeric drug delivery for the treatment of glioblastoma.

Glioblastoma (GBM) remains an almost universally fatal diagnosis. The current therapeutic mainstay consists of maximal safe surgical resection followed by radiation therapy (RT) with concomitant temozolomide (TMZ), followed by monthly TMZ (the "Stupp regimen"). Several chemotherapeutic agents have been shown to have modest efficacy in the treatment of high-grade glioma (HGG), but blood-brain barrier impermeability remains a major delivery obstacle. Polymeric drug-delivery systems, developed to allow controlled local release of biologically active substances for a variety of conditions, can achieve high local concentrations of active agents while limiting systemic toxicities. Polymerically delivered carmustine (BCNU) wafers, placed on the surface of the tumor-resection cavity, can potentially provide immediate chemotherapy to residual tumor cells during the standard delay between surgery and chemoradiotherapy. BCNU wafer implantation as monochemotherapy (with RT) in newly diagnosed HGG has been investigated in 2 phase III studies that reported significant increases in median overall survival. A number of studies have investigated the tumoricidal synergies of combination chemotherapy with BCNU wafers in newly diagnosed or recurrent HGG, and a primary research focus has been the integration of BCNU wafers into multimodality therapy with the standard Stupp regimen. Overall, the results of these studies have been encouraging in terms of safety and efficacy. However, the data must be qualified by the nature of the studies conducted. Currently, there are no phase III studies of BCNU wafers with the standard Stupp regimen. We review the rationale, biochemistry, pharmacokinetics, and research history (including toxicity profile) of this modality.

Prospective observational study of acute postlumbar laminectomy MRI.

OBJECT: Patients who develop a lower-extremity neurological deficit after lumbar laminectomy present a diagnostic dilemma. In the setting of a neurological deficit, some surgeons use MRI to evaluate for symptomatic compression of the thecal sac. The authors conducted a prospective observational cohort study in patients undergoing open lumbar laminectomy for neurogenic claudication to document the MRI appearance of the postlaminectomy spine and to determine changes in thecal sac diameter caused by the accumulation of epidural fluid. METHODS: Eligible patients who were candidates for open lumbar laminectomy for neurogenic claudication at a single neurosurgical center between August 2007 and June 2009 were enrolled. Preoperative and postoperative MRI of the lumbar spine was performed on the same MRI scanner. Postoperative MRI studies were completed within 36 hours of surgery. Routine clinical and surgical data were collected at the preoperative visit, during surgery, and postoperatively. Images were interpreted for the signal characteristics of the epidural fluid and for thecal diameter (region of interest [ROI]) by 2 blinded neuroradiologists. RESULTS: Twenty-four patients (mean age 69.7 years, range 30-83 years) were enrolled, and 20 completed the study. Single-level laminectomy was performed in 6 patients, 2-level in 12, and 3-level in 2. Preoperative canal measurements (ROI) at the most stenotic level averaged 0.26 cm(2) (range 0.0-0.46 cm(2)), and postoperative ROI at that same level averaged 0.95 cm(2) (range 0.46-2.05 cm(2)). The increase in ROI averaged 0.69 cm(2) (range 0.07-1.81 cm(2)). Seven patients (35%) had immediate postoperative weakness in at least 1 muscle group graded at 4+/5. The decline in examination was believed to be effort dependent and secondary to discomfort in the acute postoperative period. Those with weakness had smaller increases in ROI (0.51 cm(2)) than those with full strength (0.78 cm(2), p = 0.1599), but none had evidence of worsened thecal compression. On the 1st postoperative day, 19 patients were at full strength and all patients were at full strength at their 15-day follow-up. The T1-weighted epidural fluid signal was isointense in 19 of the 20 patients. The T2-weighted epidural fluid signal was hyperintense in 9, isointense in 4, and hypointense in 7 patients. CONCLUSIONS: Immediately after lumbar laminectomy, the appearance of the thecal sac on MRI can vary widely. In most patients the thecal sac diameter increases after laminectomy despite the presence of epidural blood. In this observational cohort, a reduction in thecal diameter caused by epidural fluid did not correlate with motor function. Results in the small subset of patients where the canal diameter decreased due to epidural fluid compression of the thecal sac raises the question of the utility of immediate postoperative MRI.

Amygdalar neuromelanosis intractable epilepsy without leptomeningeal involvement.

Neurocutaneous melanosis (NCM) is a rare, congenital neuroectodermal dysplasia generally resulting in early death from neurological decline due to leptomeningeal involvement. Nonmeningeal CNS epileptogenic lesions presenting in later childhood in the absence of leptomeningeal disease are rare. This report summarizes a rare presentation and curative epilepsy surgery. The authors discuss the case of a 14-year-old girl with NCM who originally presented with intractable partial-onset seizures. The MRI, PET, and SPECT studies subsequently revealed a focal epileptogenic source in the right temporal lobe. Results of video-electroencephalography monitoring concurred with the imaging findings, and a right temporal lobectomy was performed including the medial structures. Following surgery, histopathological features of the lesion included multiple scattered mononuclear cells with brown pigmentation in the amygdala specimen. The patient remains seizure free 2 years postresection, and no longer needs medication for seizure management. This patient presented with an atypical CNS manifestation of NCM that is curable by epilepsy surgery. Her intractable epilepsy developed secondary to amygdalar neuromelanosis, which had no associated leptomeningeal melanosis, an uncommon occurrence. As evidenced by the lack of seizure activity following resection, the patient's quality of life greatly improved after neurological surgery.

Functional magnetic resonance imaging of the visual cortex performed in children under sedation to assist in presurgical planning.

OBJECT: Advances in brain imaging have allowed for more sophisticated mapping of crucial neural structures. Functional MRI (fMRI) measures local changes in blood oxygenation associated with changes in neural activity and is useful in mapping cortical activation. Applications of this imaging modality have generally been restricted to cooperative patients; however, fMRI has proven successful in localizing the motor cortex for neurosurgical planning in uncooperative children under sedation. The authors demonstrate that the use of fMRI to localize the visual cortex in sedated children can be safely and effectively performed, allowing for more accurate presurgical planning to spare visual structures. METHODS: Between 2007 and 2009, 11 children (age range 1-11 years) underwent fMRI for neurosurgical planning while under sedation. Blood oxygen level-dependent fMRI was performed to detect visual cortex activation during stimulation through closed eyelids. Visual stimulation was presented in block design with periods of flashing light alternated with darkness. RESULTS: Functional MRI was successful in identifying visual cortex in each of the 11 children tested. There were no complications with propofol sedation or the fMRI. All children suffered from epilepsy, 5 had brain tumors, and 1 had tuberous sclerosis. After fMRI was performed, 6 patients underwent surgery. Frameless stereotactic guidance was synchronized with fMRI data to design an approach to spare visual structures during resection. There were no cases where a false negative led to unexpected visual field deficits or other side effects of surgery. In 2 cases, the fMRI results demonstrated that the tracts were already disrupted: in one case from a prior tumor operation and in another from dysplasia. CONCLUSIONS: Functional MRI for evaluation of visual pathways can be safely and reproducibly performed in young or uncooperative children under light sedation. Identification of primary visual cortex aids in presurgical planning to avoid vision loss in appropriately selected patients.

Endoscopic colloid cyst resection in the absence of ventriculomegaly.

BACKGROUND: The absence of ventriculomegaly has been considered an overt or relative contraindication to the endoscopic resection of colloid cysts. In the past, endoscopic removal of colloid cysts in the absence of ventriculomegaly has been considered ill advised. Reports of successful endoscopic surgery in small ventricles are surfacing. OBJECTIVE: We examined the combined experience of 2 high-volume endoscopic centers to characterize the outcomes of patients undergoing endoscopic removal of colloid cysts in small ventricles. METHODS: We retrospectively reviewed all endoscopic colloid cyst removal procedures by the 2 senior authors (P.N., C.T.) performed at the Barrow Neurological Institute over an 8-year period. Radiographic, clinical, and interview data were recorded and analyzed. The age-adjusted relative bicaudate index was used to define small ventricles. RESULTS: Sixteen patients (8 female) underwent attempted endoscopic removal of a colloid cyst in the absence of ventriculomegaly. Surgery was technically successful in 15 patients. The cyst was removed completely in 13 of patients. Short-term memory loss was initially present in 3 patients and completely resolved in all but 1 patient who had presented with short-term memory loss. Temporary complications occurred in 2 patients. CONCLUSION: Normal-size ventricles are not a contraindication to endoscopic removal of third ventricular colloid cysts. Complication rates are at least comparable to those of patients with ventriculomegaly or to those undergoing open microsurgical resection.

Endoscopic resection of colloid cysts: use of a dual-instrument technique and an anterolateral approach.

OBJECTIVE: Endoscopic approaches are increasingly utilized to treat third ventricular colloid cysts but have been associated with lower rates of complete cyst wall resection. Our objective was to assess the results of colloid cyst resection via an anterolateral endoscopic approach with a dual-instrument technique, with an emphasis on completeness of cyst wall resection. METHODS: A retrospective review of the senior author's experience with 22 colloid cysts treated with endoscopic resection since 2004 was performed. Initial cyst size, completeness of resection, postoperative radiographic residual, recurrence at follow-up, need for reoperation, and neurologic morbidity were assessed. All cysts were approached from an anterolateral trajectory with two instruments working in concert through a single endoscope. RESULTS: Of 22 patients, near-total resection was obtained in 95%. In 3 cases, a very small, radiographically occult residual was left. Complete cyst wall resection was therefore obtained in 18 (82%). There were no cases of recurrence at follow-up in any patient. No patients required craniotomy or underwent re-resection. Fifteen of 16 (94%) patients with long-term clinical follow-up remained stable or improved. CONCLUSION: High rates of complete colloid cyst resection, with low morbidity, are possible with an anterolateral endoscopic approach with dual-instrument technique. These results support the findings of other endoscopists that show how technical modifications to traditional endoscopic approaches can produce favorable results.

Firing behavior and network activity of single neurons in human epileptic hypothalamic hamartoma.

OBJECTIVE: Human hypothalamic hamartomas (HH) are intrinsically epileptogenic and are associated with treatment-resistant gelastic seizures. The basic cellular mechanisms responsible for seizure onset within HH are unknown. We used intra-operative microwire recordings of single neuron activity to measure the spontaneous firing rate of neurons and the degree of functional connection between neurons within the tumor. TECHNIQUE: Fourteen patients underwent transventricular endoscopic resection of HH for treatment-resistant epilepsy. Prior to surgical resection, single neuron recordings from bundled microwires (total of nine contacts) were obtained from HH tissue. Spontaneous activity was recorded for two or three 5-min epochs under steady-state general anesthesia. Off-line analysis included cluster analysis of single unit activity and probability analysis of firing relationships between pairs of neurons. RESULTS: Altogether, 222 neurons were identified (mean 6 neurons per recording epoch). Cluster analysis of single neuron firing utilizing a mixture of Gaussians model identified two distinct populations on the basis of firing rate (median firing frequency 0.6 versus 15.0 spikes per second; p < 10(-5)). Cluster analysis identified three populations determined by levels of burst firing (median burst indices of 0.015, 0.18, and 0.39; p < 10(-15)). Unbiased analysis of spontaneous single unit behavior showed that 51% of all possible neuron pairs within each recording epoch had a significant level of firing synchrony (p < 10(-15)). The subgroup of neurons with higher median firing frequencies was more likely to demonstrate synchronous firing (p < 10(-7)). CONCLUSION: Hypothalamic hamartoma tissue in vivo contains neurons which fire spontaneously. The activity of single neurons is diverse but distributes into at least two electrophysiological phenoytpes. Functional linkage between single neurons suggests that HH neurons exist within local networks that may contribute to ictogenesis.

Eight-second MRI scan for evaluation of shunted hydrocephalus.

INTRODUCTION: Pediatric patients harboring shunts placed early in life are subjected to numerous radiographic studies during development of their central nervous system. Radiation is detrimental to these young patients. MRI avoids the risk of radiation but is thought more difficult due to the increased time a young patient must lie motionless during scan acquisition. Optimal radiographic interrogation would be quick, radiation-free, and allow adequate ventricular evaluation. METHODS: We queried the electronic medical records system of the senior author (SE) for the terms "hydrocephalus" and "shunt malfunction." All patients currently younger than 18 years were included. In the last 5 years, pediatric patients have been evaluated in an office setting with a limited MRI sequence (T1 sagittal, T2 axial, T1 axial, and DWI) lasting a total of 178 s. In the event of significant motion artifact, the total sequence is abandoned and an 8-s T2 diffusion-weighted scan is performed. RESULTS: Forty-four patients were included in the study (20 males, average age 10.4 yrs). Eighty-eight rapid acquisition scans were obtained. Adequate ventricular evaluation was performed without sedation in every case. In each instance where there was motion, the 8-s scan provided adequate ventricular evaluation. CONCLUSION: Rapid acquisition MRI scanning avoids the deleterious cumulative effects of radiation in pediatric patients and allows adequate evaluation of the ventricles without the need for sedation.