Aneurysmal bone cysts (ABCs) are benign, expansile, osteolytic lesions that represent 1%–2% of primary bone tumors. Cranial ABCs are even more rare and represent 3%–6% of these unique lesions. The authors describe the case of a 3-year-old girl who presented with an acute posterior fossa epidural hematoma after minor trauma. Imaging workup revealed a previously undiagnosed suboccipital ABC that appeared to have ruptured as a result of her trauma, leading to a life-threatening hemorrhage. To the authors' knowledge, a ruptured ABC has never before been presented in the pediatric literature. In this case report, the authors review the imaging findings, natural history, clinical course, and treatment of these rare lesions.
Sarah T. Garber and Jay K. Riva-Cambrin
Jian Guan, Jay Riva-Cambrin and Douglas L. Brockmeyer
Patients treated for Chiari I malformation (CM-I) with posterior fossa decompression (PFD) may occasionally and unpredictably develop postoperative hydrocephalus. The clinical risk factors predictive of this type of Chiari-related hydrocephalus (CRH) are unknown. The authors' objective was to evaluate their experience to identify risk factors that may predict which of these patients undergoing PFD will develop CRH after surgery.
The authors performed a retrospective clinical chart review of all patients who underwent PFD surgery and duraplasty for CM-I at the Primary Children's Hospital in Utah from June 1, 2005, through May 31, 2015. Patients were dichotomized based on the need for long-term CSF diversion after PFD. Analysis included both univariate and multivariable logistic regression analyses.
The authors identified 297 decompressive surgeries over the period of the study, 22 of which required long-term postoperative CSF diversion. On multivariable analysis, age < 6 years old (OR 3.342, 95% CI 1.282–8.713), higher intraoperative blood loss (OR 1.003, 95% CI 1.001–1.006), and the presence of a fourth ventricular web (OR 3.752, 95% CI 1.306–10.783) were significantly associated with the need for long-term CSF diversion after decompressive surgery.
Younger patients, those with extensive intraoperative blood loss, and those found during surgery to have a fourth ventricular web were at higher risk for the development of CRH. Clinicians should be alert to evidence of CRH in this patient population after PFD surgery.
JNSPG 75th Anniversary Invited Review Article
John R. W. Kestle and Jay Riva-Cambrin
Prospective multicenter clinical research studies in pediatric hydrocephalus are relatively rare. They cover a broad spectrum of hydrocephalus topics, including management of intraventricular hemorrhage in premature infants, shunt techniques and equipment, shunt outcomes, endoscopic treatment of hydrocephalus, and prevention and treatment of infection. The research methodologies include randomized trials, cohort studies, and registry-based studies. This review describes prospective multicenter studies in pediatric hydrocephalus since 1990. Many studies have included all forms of hydrocephalus and used device or procedure failure as the primary outcome. Although such studies have yielded useful findings, they might miss important treatment effects in specific subgroups. As multicenter study networks grow, larger patient numbers will allow studies with more focused entry criteria based on known and evolving prognostic factors. In addition, increased use of patient-centered outcomes such as neurodevelopmental assessment and quality of life should be measured and emphasized in study results. Well-planned multicenter clinical studies can significantly affect the care of children with hydrocephalus and will continue to have an important role in improving care for these children and their families.
Cydni N. Williams, Jay Riva-Cambrin and Susan L. Bratton
Cerebral salt wasting (CSW) and the syndrome of inappropriate antidiuretic hormone secretion (SIADH) cause postoperative hyponatremia in neurosurgery patients, can be difficult to distinguish clinically, and are associated with increased morbidity. The authors aimed to determine risk factors associated with CSW and SIADH among children undergoing surgery for intracranial tumors.
This retrospective cohort study included children 0–19 years of age who underwent a first intracranial tumor surgery with postoperative hyponatremia (sodium ≤ 130 mEq/L). CSW was differentiated from SIADH by urine output and fluid balance, exclusive of other causes of hyponatremia. The CSW and SIADH groups were compared with basic bivariate analysis and recursive partitioning.
Of 39 hyponatremic patients, 17 (44%) had CSW and 10 (26%) had SIADH. Patients with CSW had significantly greater natriuresis compared with those with SIADH (median urine sodium 211 vs 28 mEq/L, p = 0.01). Age ≤ 7 years and female sex were significant risk factors for CSW (p = 0.03 and 0.04, respectively). Both patient groups had hyponatremia onset within the first postoperative week. Children with CSW had trends toward increased sodium variability and symptomatic hyponatremia compared with those with SIADH. Most received treatment, but inappropriate treatment was noted to worsen hyponatremia.
The authors found that CSW was more common following intracranial tumor surgery and was associated with younger age and female sex. Careful assessment of fluid balance and urine output can separate patients with CSW from those who have SIADH, and high urine sodium concentrations (> 100 mEq/L) support a CSW diagnosis. Patients with CSW and SIADH had similar clinical courses, but responded to different interventions, making appropriate diagnosis and treatment imperative to prevent morbidity.
John R. W. Kestle
Sarah T. Garber, Robert J. Bollo and Jay K. Riva-Cambrin
Pediatric spinal pilomyxoid astrocytoma (PMA) is an extremely rare tumor that merits recognition as a specific, unique entity. The authors present the case of an intramedullary PMA in the thoracic spinal cord of an 11-year-old boy who presented with back pain, scoliosis, and multiple lung nodules. The patient underwent T5–11 laminoplasty and near-total resection of the spinal tumor. The final pathological diagnosis was WHO Grade II PMA. The patient did well for 14 months until the tumor progressed both clinically and radiographically. A literature review focusing on the clinical characteristics, histology, and treatment of PMAs provides a better understanding of these rare lesions. Because of the small number of cases optimal treatment guidelines have not been established, but gross-total resection and adjuvant chemotherapy with alkylating agents appear to confer a better long-term prognosis. Pediatric patients with PMAs can remain recurrence free at least 5 years after surgery, although these tumors may disseminate or dedifferentiate into more malignant gliomas. Recognition of intramedullary PMA as a unique entity in children is vital to the development of specific surgical and adjuvant treatment regimens.
Robert J. Bollo, Jay Riva-Cambrin, Meghan M. Brockmeyer and Douglas L. Brockmeyer
Chiari malformation Type I (CM-I) is a congenital anomaly often treated by decompressive surgery. Patients who fail to respond to standard surgical management often have complex anomalies of the craniovertebral junction and brainstem compression, requiring reduction and occipitocervical fusion. The authors hypothesized that a subgroup of “complex” patients defined by specific radiographic risk factors may have a higher rate of requiring occipitocervical fusion.
A retrospective review was conducted of clinical and radiographic data in pediatric patients undergoing surgery for CM-I between 1995 and 2010. The following radiographic criteria were identified: scoliosis, syringomyelia, CM Type 1.5, medullary kinking, basilar invagination, tonsillar descent, craniocervical angulation (clivoaxial angle [CXA] < 125°), and ventral brainstem compression (pB–C2 ≥ 9 mm). A multivariate Cox regression analysis was used to determine the independent association between occipitocervical fusion and each variable.
Of the 206 patients who underwent CM decompression with or without occipitocervical fusion during the study period, 101 had preoperative imaging available for review and formed the study population. Mean age at surgery was 9.1 years, and mean follow-up was 2.3 years. Eighty-two patients underwent suboccipital decompression alone (mean age 8.7 years). Nineteen patients underwent occipitocervical fusion (mean age 11.1 years), either as part of the initial surgical procedure or in a delayed fashion. Factors demonstrating a significantly increased risk of requiring fusion were basilar invagination (HR 9.8, 95% CI 2.2–44.2), CM 1.5 (HR 14.7, 95% CI 1.8–122.5), and CXA < 125° (HR 3.9, 95% CI 1.2–12.6).
Patients presenting with basilar invagination, CM 1.5, and CXA < 125° are at increased risk of requiring an occipitocervical fusion procedure either as an adjunct to initial surgical decompression or in a delayed fashion. Patients and their families should be counseled in regard to these findings as part of a preoperative CM evaluation.
Heather S. Spader, Robert J. Bollo, Christian A. Bowers and Jay Riva-Cambrin
Intrathecal baclofen infusion systems to manage severe spasticity and dystonia are associated with higher infection rates in children than in adults. Factors unique to this population, such as poor nutrition and physical limitations for pump placement, have been hypothesized as the reasons for this disparity. The authors assessed potential risk factors for infection in a multivariate analysis.
Patients who underwent implantation of a programmable pump and intrathecal catheter for baclofen infusion at a single center between January 1, 2000, and March 1, 2012, were identified in this retrospective cohort study. The primary end point was infection. Potential risk factors investigated included preoperative (i.e., demographics, body mass index [BMI], gastrostomy tube, tracheostomy, previous spinal fusion), intraoperative (i.e., surgeon, antibiotics, pump size, catheter location), and postoperative (i.e., wound dehiscence, CSF leak, and number of revisions) factors. Univariate analysis was performed, and a multivariate logistic regression model was created to identify independent risk factors for infection.
A total of 254 patients were evaluated. The overall infection rate was 9.8%. Univariate analysis identified young age, shorter height, lower weight, dehiscence, CSF leak, and number of revisions within 6 months of pump placement as significantly associated with infection. Multivariate analysis identified young age, dehiscence, and number of revisions as independent risk factors for infection.
Young age, wound dehiscence, and number of revisions were independent risk factors for infection in this pediatric cohort. A low BMI and the presence of either a gastrostomy or tracheostomy were not associated with infection and may not be contraindications for this procedure.
Abhaya V. Kulkarni, Jay Riva-Cambrin and Samuel R. Browd
Published case series of endoscopic third ventriculostomy (ETV) for childhood hydrocephalus have reported widely varying success rates. The authors recently developed and internally validated the ETV Success Score (ETVSS); this is a simplified means of predicting the 6-month success rate of ETV for a child with hydrocephalus, based on age, etiology of hydrocephalus, and presence of a previous shunt. The authors hypothesized that the ETVSS would be able to predict with reasonable accuracy the actual ETV success rate reported among published case series.
A literature search was performed to identify published pediatric ETV papers that contained enough information with which to calculate an aggregate, mean predicted ETVSS for the cohort. This was then compared with the actual ETV success rate in the cohort. Data were extracted independently in triplicate, including by 2 individuals who were not involved with the development of the ETVSS.
Fifteen papers reporting on 322 patients were included. Interrater reliability was very high in determining the predicted ETVSS (intraclass correlation coefficient 0.99). The predicted ETVSS for each paper agreed strongly with the actual ETV success rate reported in each paper (reliability intraclass correlation coefficient 0.81). There was no significant difference in the magnitude of the predicted ETVSS and the actual ETV success (p = 0.98, paired t-test). In a linear regression model, the predicted ETVSS explained 62% of the variation in actual ETV success. When the entire cohort was combined and analyzed together, the overall mean predicted ETVSS was 57.9%, which was nearly identical to the actual ETV success rate of 59.2%.
The ETVSS closely predicts the actual ETV success rate reported in selected papers published over the last 20 years and explains much of the variation.
Won Hyung A. Ryu, Michael M. H. Yang, Sandeep Muram, W. Bradley Jacobs, Steven Casha and Jay Riva-Cambrin
As the cost of health care continues to increase, there is a growing emphasis on evaluating the relative economic value of treatment options to guide resource allocation. The objective of this systematic review was to evaluate the current evidence regarding the cost-effectiveness of cranial neurosurgery procedures.
The authors performed a systematic review of the literature using PubMed, EMBASE, and the Cochrane Library, focusing on themes of economic evaluation and cranial neurosurgery following the Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) guidelines. Included studies were publications of cost-effectiveness analysis or cost-utility analysis between 1995 and 2017 in which health utility outcomes in life years (LYs), quality-adjusted life years (QALYs), or disability-adjusted life years (DALYs) were used. Three independent reviewers conducted the study appraisal, data abstraction, and quality assessment, with differences resolved by consensus discussion.
In total, 3485 citations were reviewed, with 53 studies meeting the inclusion criteria. Of those, 34 studies were published in the last 5 years. The most common subspecialty focus was cerebrovascular (32%), followed by neurooncology (26%) and functional neurosurgery (24%). Twenty-eight (53%) studies, using a willingness to pay threshold of US$50,000 per QALY or LY, found a specific surgical treatment to be cost-effective. In addition, there were 11 (21%) studies that found a specific surgical option to be economically dominant (both cost saving and having superior outcome), including endovascular thrombectomy for acute ischemic stroke, epilepsy surgery for drug-refractory epilepsy, and endoscopic pituitary tumor resection.
There is an increasing number of cost-effectiveness studies in cranial neurosurgery, especially within the last 5 years. Although there are numerous procedures, such as endovascular thrombectomy for acute ischemic stroke, that have been conclusively proven to be cost-effective, there remain promising interventions in current practice that have yet to meet cost-effectiveness thresholds.