Cranial Vault Remodeling in Children With Ventricular Shunts.

INTRODUCTION: Cranial vault surgery in children with ventricular shunts is more complex due to the possible interference of shunt location with surgical planning and increased risk of shunt related complications. The study evaluated the management of ventricular shunts during cranial vault remodeling (CVR) and subsequent outcomes and complications following CVR. METHODS: An IRB-approved retrospective chart review was performed including patients who underwent CVR in presence of a ventricular shunt. Measured outcomes were number of shunt revisions following CVR, 30-day complication rate, 3-month complication rate, and post-CVR Whitaker classification. Finally, a review of the literature was performed, and our results were compared to previous reports. RESULTS: Eleven patients met the inclusion criteria. Ventricular shunt was not exposed in 18%; exposed and not revised in 54%; exposed and left on a bone peninsula in 18% and simultaneously exposed and revised in 18%. Two patients experienced complications within 30-days. Three additional patients experienced complications within 3-months. An average of 2.2 shunt revisions per patient were performed following CVR. Whitaker classification was I in 7 patients, II in 1 patient and III in 2 patients. Shunt revision rate for patients undergoing CVR for hydrocephalic macrocephaly was on average of 1.2 and 1.9 for shunt-induced craniosynostosis in literature. CONCLUSIONS: Cranial vault abnormalities in the presence of a ventricular shunt can be effectively treated with CVR. The presence of a shunt does not seem to interfere with final head shape. While leaving the shunt unexposed may appear less morbid, shunt related complications can still occur with this approach.

Neonatal Hyponatremia in the Setting of Untreated Progressive Hydrocephalus.

BACKGROUND: Hyponatremia in the neonatal population is an uncommon occurrence and can be associated with significant increase in morbidity and mortality. In the neonatal population, it is typically associated with an excess of antidiuretic hormone and rarely has been found to be associated with hydrocephalus, short of being caused by the subsequent treatment of hydrocephalus. CASE DESCRIPTION: We present a case report of a patient with neonatal hydrocephalus, secondary to intraventricular hemorrhage in the setting of prematurity, treated at our institution, in whom sodium levels reached a nadir as head circumference peaked and subsequent treatment of hydrocephalus resolved the associated hyponatremia. CONCLUSIONS: Hydrocephalus secondary to intraventricular hemorrhage is a notable complication in the premature neonatal population. Physicians should be aware of its potential association with hyponatremia and consider early neurosurgical intervention when other etiologies of the electrolyte disturbance cannot be identified.

Reconstruction of Secondary Calvarial Defects with Ex Situ Split Calvarial Bone Grafts: Long-Term Evaluation of Outcomes.

BACKGROUND: Autologous bone continues to represent the first choice for reconstruction of calvarial defects. However, unanswered questions remain on the natural history of the graft and the influence of patient-related risk factors. This study investigated the outcomes of skull reconstruction with split calvarial bone graft, examining the natural history and stratifying the risk of unfavorable results. METHODS: Patients who underwent cranioplasty with split calvarial bone graft between 1982 and 2016 at the Cleveland Clinic were analyzed, recording demographics, comorbidities, indications, size and location of defect, and outcomes including complications and reoperations. Changes in graft thickness were analyzed using computed tomographic and magnetic resonance imaging scans. RESULTS: Forty-one patients with an average age of 33.2 years, cranial defect size of 68 cm, and mean follow-up of 28 months were included. The majority of patients (85 percent) had significant risk factors, with 43 percent suffering prior infection. Seventy-three percent of patients experienced successful restoration. A major complication was recorded in 26.8 percent; resorption occurred in 19.5 percent of patients (in 75 percent only at the recipient site), with 9.8 percent requiring reoperation. Patients with one or more risk factors or a smoking history were more likely to experience a complication. The mean ratio of the graft to the bicortical donor bone thickness was 0.48 ± 0.17 for the recipient site and 0.57 ± 0.10 for the donor site at an average radiographic follow-up of 11.9 ± 10.9 years. CONCLUSIONS: This study demonstrated a 73.2 percent first-attempt success rate in a high-risk population. The grafts maintain thickness over time, with no evidence of bone hypertrophy. Defect characteristics and patient systemic factors appear to be important variables influencing success. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, IV.

Chiari-related scoliosis: a single-center experience with long-term radiographic follow-up and relationship to deformity correction.

OBJECTIVE Previous reports have addressed the short-term response of patients with Chiari-related scoliosis (CRS) to suboccipital decompression and duraplasty (SODD); however, the long-term behavior of the curve has not been well defined. The authors undertook a longitudinal study of a cohort of patients who underwent SODD for CRS to determine whether there are factors related to Chiari malformation (CM) that predict long-term scoliotic curve behavior and need for deformity correction. METHODS The authors retrospectively reviewed cases in which patients underwent SODD for CRS during a 14-year period at a single center. Clinical (age, sex, and associated disorders/syndromes) and radiographic (CM type, tonsillar descent, pBC2 line, clival-axial angle [CXA], syrinx length and level, and initial Cobb angle) information was evaluated to identify associations with the primary outcome: delayed thoracolumbar fusion for progressive scoliosis. RESULTS Twenty-eight patients were identified, but 4 were lost to follow-up and 1 underwent fusion within a year. Among the remaining 23 patients, 11 required fusion surgery at an average of 88.3 ± 15.4 months after SODD, including 7 (30%) who needed fusion more than 5 years after SODD. On univariate analysis, a lower CXA (131.5° ± 4.8° vs 146.5° ± 4.6°, p = 0.034), pBC2 > 9 mm (64% vs 25%, p = 0.06), and higher initial Cobb angle (35.1° ± 3.6° vs 22.8° ± 4.0°, p = 0.035) were associated with the need for thoracolumbar fusion. Multivariable modeling revealed that lower CXA was independently associated with a need for delayed thoracolumbar fusion (OR 1.12, p = 0.0128). CONCLUSIONS This investigation demonstrates the long-term outcome and natural history of CRS after SODD. The durability of the effect of SODD on CRS and curve behavior is poor, with late curve progression occurring in 30% of patients. Factors associated with CRS progression include an initial pBC2 > 9 mm, lower CXA, and higher Cobb angle. Lower CXA was an independent predictor of delayed thoracolumbar fusion. Further study is necessary on a larger cohort of patients to fully elucidate this relationship.

Risk factors for progressive neuromuscular scoliosis requiring posterior spinal fusion after selective dorsal rhizotomy.

OBJECTIVE Selective dorsal rhizotomy (SDR) via limited laminectomy is an effective treatment of lower-extremity spasticity in the pediatric population. Children with spasticity are also at risk for neuromuscular scoliosis; however, specific risk factors for progressive spinal deformity requiring posterior spinal fusion (PSF) after SDR are unknown. The authors' goal was to identify potential risk factors. METHODS The authors performed a retrospective cohort study of patients who underwent SDR via limited laminectomy between 2003 and 2014 and who had at least 1 year of follow-up. They analyzed demographic, clinical, and radiographic variables to elucidate risk factors for progressive neuromuscular scoliosis. The primary outcome was need for PSF. RESULTS One hundred thirty-four patients underwent SDR and had at least 12 months of follow-up (mean 65 months); 48 patients (36%) had detailed pre- and postoperative radiographic data available. The mean age at surgery was 10 years (SD 5.1 years). Eighty-four patients (63%) were ambulatory before SDR, 109 (82%) underwent a single-level laminectomy, and a mean of 53% of the dorsal rootlets from L-1 to S-1 were sectioned. Fifteen patients (11.2%) subsequently required PSF for progressive deformity. Nonambulatory status (p < 0.001) and a preoperative Cobb angle > 30° (p = 0.003) were significantly associated with PSF on univariate analysis, but no statistically significant correlation was found with any clinical or radiographic variable and PSF after SDR on multivariate regression analysis. CONCLUSIONS Patients with preoperative nonambulatory status and Cobb angle > 30° may be at risk for progressive spinal deformity requiring PSF after SDR. These are well-known risk factors for progressive deformity in children with spasticity in general. Although our analysis suggests SDR via limited laminectomy may not significantly accelerate the development of neuromuscular scoliosis, further case-control studies are critical to elucidate the impact of SDR on spinal deformity.

Mature salivary gland rests within sonic hedgehog-positive medulloblastoma: case report and insights into the molecular genetics and embryopathology of ectopic intracranial salivary gland analogs.

Intracranial ectopic salivary gland rests within dural-based lesions are reported very infrequently in the literature. The authors report the unique case of a 12-year-old boy with a cerebellar medulloblastoma positive for sonic hedgehog (Shh) that contained intraaxial mature ectopic salivary gland rests. The patient underwent clinical and radiological monitoring postoperatively, until he died of disseminated disease. An autopsy showed no evidence of salivary glands within disseminated lesions. The intraaxial presence of salivary gland rests and concomitant Shh positivity of the described tumor point to a disorder in differentiation as opposed to ectopic developmental foci, which are uniformly dural based in the described literature. The authors demonstrate the characteristic "papilionaceous" appearance of the salivary glands with mucicarmine stain and highlight the role of Shh signaling in explaining the intraaxial presence of seromucous gland analogs. This article reports the first intraaxial posterior fossa tumor with heterotopic salivary gland rests, and it provides molecular and embryopathological insights into the development of these lesions.

Human prion diseases: surgical lessons learned from iatrogenic prion transmission.

The human prion diseases, or transmissible spongiform encephalopathies, have captivated our imaginations since their discovery in the Fore linguistic group in Papua New Guinea in the 1950s. The mysterious and poorly understood "infectious protein" has become somewhat of a household name in many regions across the globe. From bovine spongiform encephalopathy (BSE), commonly identified as mad cow disease, to endocannibalism, media outlets have capitalized on these devastatingly fatal neurological conditions. Interestingly, since their discovery, there have been more than 492 incidents of iatrogenic transmission of prion diseases, largely resulting from prion-contaminated growth hormone and dura mater grafts. Although fewer than 9 cases of probable iatrogenic neurosurgical cases of Creutzfeldt-Jakob disease (CJD) have been reported worldwide, the likelihood of some missed cases and the potential for prion transmission by neurosurgery create considerable concern. Laboratory studies indicate that standard decontamination and sterilization procedures may be insufficient to completely remove infectivity from prion-contaminated instruments. In this unfortunate event, the instruments may transmit the prion disease to others. Much caution therefore should be taken in the absence of strong evidence against the presence of a prion disease in a neurosurgical patient. While the Centers for Disease Control and Prevention (CDC) and World Health Organization (WHO) have devised risk assessment and decontamination protocols for the prevention of iatrogenic transmission of the prion diseases, incidents of possible exposure to prions have unfortunately occurred in the United States. In this article, the authors outline the historical discoveries that led from kuru to the identification and isolation of the pathological prion proteins in addition to providing a brief description of human prion diseases and iatrogenic forms of CJD, a brief history of prion disease nosocomial transmission, and a summary of the CDC and WHO guidelines for prevention of prion disease transmission and decontamination of prion-contaminated neurosurgical instruments.

Holospinal epidural abscess of the spinal axis: two illustrative cases with review of treatment strategies and surgical techniques.

Despite the increasing prevalence of spinal infections, the subcategory of holospinal epidural abscesses (HEAs) is extremely infrequent and requires unique management. Panspinal imaging (preferably MRI), modern aggressive antibiotic therapy, and prompt surgical intervention remain the standard of care for all spinal axis infections including HEAs; however, the surgical decision making on timing and extent of the procedure still remain ill defined for HEAs. Decompression including skip laminectomies or laminoplasties is described, with varied clinical outcomes. In this review the authors present the illustrative cases of 2 patients with HEAs who were treated using skip laminectomies and epidural catheter irrigation techniques. The discussion highlights different management strategies including the role of conservative (nonsurgical) management in these lesions, especially with an already identified pathogen and the absence of mass effect on MRI or significant neurological defects. Among fewer than 25 case reports of HEA published in the past 25 years, the most important aspect in deciding a role for surgery is the neurological examination. Nearly 20% were treated successfully with medical therapy alone if neurologically intact. None of the reported cases had an associated cranial infection with HEA, because the dural adhesion around the foramen magnum prevented rostral spread of infection. Traditionally a posterior approach to the epidural space with irrigation is performed, unless an extensive focal ventral collection is causing cord compression. Surgical intervention for HEA should be an adjuvant treatment strategy for all acutely deteriorating patients, whereas aspiration of other infected sites like a psoas abscess can determine an infective pathogen, and appropriate antibiotic treatment may avoid surgical intervention in the neurologically intact patient.

Sonic Hedgehog signaling and potential therapeutic indications.

Sonic hedgehog (Shh) is a glycoprotein molecule that is expressed throughout the central nervous system (CNS). It is important during neurodevelopment, particularly through its induction of endogenous neural precursor cells and neural stem cells. The signaling system by which Shh has its diffuse effects on multiple end organs depends on a downstream signaling cascade initiated by binding to the receptor Patched (PTC) on Shh-specific target cells. The downstream signaling cascade has widespread effects on multiple organ systems. Research into tumor suppressive effects and germline mutations has uncovered important implications in neuro-oncology. Modulating the neuroproliferative effects of the Shh signaling cascade implicated a potential role in ameliorating the effects of CNS injury, particularly in animal models of spinal cord injury and cerebral cortical ischemia. This chapter provides a summary of the Shh signaling mechanism and a review of its impact in these neurological disorders.