Chiari malformation Type I surgery in pediatric patients. Part 2: complications and the influence of comorbid disease in California, Florida, and New York

Long-term outcomes following posterior fossa decompression in pediatric patients with Chiari malformation type 1, a population-based cohort study

OBJECTIVE

Posterior fossa decompression for Chiari malformation type I (Chiari 1) is effective and associated with a low risk of complication. However, up to 20% of patients may experience continued deficits or recurring symptoms after surgical intervention. For pediatric patients, there are no established tools to predict outcomes, and the risk factors for unfavorable postoperative outcomes are poorly understood. Hence, our aim was to investigate baseline data and early postoperative predictors of poor outcomes as determined by the Chicago Chiari outcome scale (CCOS).

METHODS

All pediatric patients (< 18 years) receiving a posterior fossa decompression for Chiari 1 between the years of 2005 and 2020 at the study center were eligible for inclusion. Patients with congenital anomalies were excluded.

RESULTS

Seventy-one pediatric patients with a median age of 9 years were included. Most patients (58%) were females. Chiari 1 was associated with syringomyelia (51%), scoliosis (37%), and hydrocephalus (7%). Perioperative complications occurred in 13 patients (18%) of which two required additional procedures under general anesthesia. On multivariable proportional odds logistic regression, motor deficits (OR: 0.09; CI95%: [0.01-0.62]; p = 0.015), and surgical complications (OR: 0.16; CI95%: [0.41-0.66]; p = 0.011) were significant predictors of worse outcomes. The presence of syringomyelia was identified as a predictor of better outcomes (OR: 4.42 CI95% [1.02-19.35]; p = 0.048). A persistent hydrocephalus during the early postoperative period after posterior fossa decompression was a strong predictor of worse long-term CCOS (OR: 0.026; CI95%: [0.002-0.328]; p = 0.005).

CONCLUSION

Results from this study indicate that the existence of motor deficits and syringomyelia prior to surgery, and surgical complications and persistent hydrocephalus despite posterior fossa decompression, were useful predictors of long-term outcome.

Chiari Type I Revision Decompressive Surgery Indications and Operative Technique: Experience in a Large Adult Cohort

BACKGROUND

Chiari malformation is characterized by inferior displacement of the cerebellar tonsils through the foramen magnum, frequently resulting in strain related headaches, and motor/sensory dysfunction. Chiari decompression technique varies significantly, possibly contributing to frequent revisions. We reviewed revision Chiari decompressions at our institution to determine the primary indications for revision and outcomes after revision.

METHODS

We retrospectively reviewed patients who underwent revision of Chiari decompression at our institution from 2005 to 2020. Demographics, indications for revision surgery, operative techniques, imaging findings, and preoperative/postoperative symptoms were collected. χ2 test was performed to determine statistical significance using a P < 0.05. Independent predictors of operative outcomes were identified.

RESULTS

A total of 46 patients (91% females, mean age 38.8 years) were included for analysis. The median time to revision surgery was 69.1 months (range 0-364 months) with headache (n = 37, 80%) being the most commonly recurring symptom. Large craniectomy (n = 28, 61%) was the most frequent indication for revision surgery. Thirty-two (70%) patients underwent cranioplasty, 20 (43%) required duraplasty, 15 (33%) required arachnoid dissection, and 15 (33%) required tonsillar reduction during revision surgery. Postrevision follow-up (at 8.9 ± 5.2 months average, range 1-18 months), revealed an average reduction in all Chiari-related symptoms relative to symptoms before the revision.

CONCLUSIONS

The most common indication for revision Chiari decompression was a large craniectomy resulting in cerebellar ptosis. We found that tonsillar reduction paired with modest craniectomy achieved near-complete resolution of symptoms with minimal complications. For patients with recurrent or persistent sequelae of Chiari malformation after decompression, revision may reduce symptom severity.

Influence of affective disorders on outcomes after suboccipital decompression for adult Chiari I malformation

INTRODUCTION

Affective disorders (AD) have been shown to influence patient outcomes and healthcare resource utilization across several pathologies, though this relationship has not been described in patients with Chiari I malformations (CM-I). The aim of this study was to determine the impact of comorbid AD on postoperative events and healthcare resource utilization in adults following suboccipital decompression for CM-I.

METHODS

A retrospective study was performed using the 2016-2019 National Inpatient Sample database. Adults who underwent suboccipital decompression for CM-I were identified using ICD-10-CM codes. Patients were stratified into two cohorts, those with AD and those without (No AD). Patient demographics, comorbidities, operative characteristics, perioperative adverse events (AEs), and healthcare resource utilization were assessed. Multivariate logistic regression analyses were used to identify independent predictors of prolonged length of stay (LOS), exorbitant admission costs, and non-routine discharge (NRD).

RESULTS

A total of 3985 patients were identified, of which 2780 (69.8%) were in the No AD cohort and 1205 (30.2%) were in the AD cohort. Patient demographics were similar, except for a greater proportion of Female patients than the No AD cohort (p = 0.004). Prevalence of some comorbidities varied between cohorts, including obesity (p = 0.030), ADHD (p < 0.001), GERD (p < 0.001), smoking (p < 0.001), and chronic pulmonary disease (p < 0.001). The AD cohort had a greater proportion of patients with 1-2 (p < 0.001) or ≥ 3 comorbidities (p < 0.001) compared to the No AD cohort. A greater proportion of patients in the AD cohort presented with headache compared to the No AD cohort (p = 0.003). Incidence of syringomyelia was greater in the No AD cohort (p = 0.002). A greater proportion of patients in the No AD cohort underwent duraplasty only (without cervical laminectomy) compared to the AD cohort (p = 0.021). Healthcare resource utilization was similar between cohorts, with no significant differences in mean LOS (No AD: 3.78 ± 3.51 days vs. 3.68 ± 2.71 days, p = 0.659), NRD (No AD: 3.8% vs. AD: 5.4%, p = 0.260), or mean admission costs (No AD: $20,254 ± 14,023 vs. AD: $29,897 ± 22,586, p = 0.284). On multivariate analysis, AD was not independently associated with extended LOS [OR (95%CI): 1.09 (0.72-1.65), p = 0.669], increased hospital costs [OR (95%CI): 0.98 (0.63-1.52), p = 0.930], or NRD [OR (95%CI): 1.39 (0.65-2.96), p = 0.302].

CONCLUSION

Our study suggests that the presence of an AD may not have as much of an impact on postoperative events and healthcare resource utilization in adult patients undergoing Chiari decompression. Additional studies may be warranted to identify other potential implications that AD may have in other aspects of healthcare in this patient population.

Concurrent Presence of Thoracolumbar Scoliosis and Chiari Malformation: Is Operative Risk Magnified?

STUDY DESIGN

Retrospective review of Kids' Inpatient Database (KID).

PURPOSE

Identify the risks and complications associated with surgery in adolescents diagnosed with Chiari and scoliosis.

OVERVIEW OF LITERATURE

Scoliosis is frequently associated with Chiari malformation (CM). More specifically, reports have been made about this association with CM type I in the absence of syrinx status.

METHODS

The KID was used to identify all pediatric inpatients with CM and scoliosis. The patients were stratified into three groups: those with concomitant CM and scoliosis (CMS group), those with only CM (CM group), and those with only scoliosis (Sc group). Multivariate logistic regressions were used to assess association between surgical characteristics and diagnosis with complication rate.

RESULTS

A total of 90,707 spine patients were identified (61.8% Sc, 37% CM, 1.2% CMS). Sc patients were older, had a higher invasiveness score, and higher Charlson comorbidity index (all p<0.001). CMS patients had significantly higher rates of surgical decompression (36.7%). Sc patients had significantly higher rates of fusions (35.3%) and osteotomies (1.2%, all p<0.001). Controlling for age and invasiveness, postoperative complications were significantly associated with spine fusion surgery for Sc patients (odds ratio [OR], 1.8; p<0.05). Specifically, posterior spinal fusion in the thoracolumbar region had a greater risk of complications (OR, 4.9) than an anterior approach (OR, 3.6; all p<0.001). CM patients had a significant risk of complications when an osteotomy was performed as part of their surgery (OR, 2.9) and if a spinal fusion was concurrently performed (OR, 1.8; all p<0.05). Patients in the CMS cohort were significantly likely to develop postoperative complications if they underwent a spinal fusion from both anterior (OR, 2.5) and posterior approach (OR, 2.7; all p<0.001).

CONCLUSIONS

Having concurrent scoliosis and CM increases operative risk for fusion surgeries despite approach. Being independently inflicted with scoliosis or Chiari leads to increased complication rate when paired with thoracolumbar fusion and osteotomies; respectively.

Endoscopic third ventriculostomy for the management of children with cerebrospinal fluid disorders, ventriculomegaly, and associated Chiari I malformation

OBJECTIVES

Our objective was to review the outcomes of children with CIM and associated cerebrospinal fluid (CSF) disorders and ventriculomegaly undergoing endoscopic third ventriculostomy (ETV) as a primary intervention.

MATERIALS AND METHODS

A retrospective, single-center, observational cohort study was conducted of consecutive children with CIM with associated CSF disorders and ventriculomegaly treated first by ETV between January 2014 and December 2020.

RESULTS

Raised intracranial pressure symptoms were the most frequent in ten patients, followed by posterior fossa and syrinx symptoms in three cases. One patient had a later stoma closure and required a shunt insertion. The success rate of the ETV in the cohort was 92% (11/12). There was no surgical mortality in our series. No other complications were reported. The median herniation of the tonsils was not statistically different in the pre vs. post-operative MRI (1.14 vs. 0.94, p=0.1). However, the median Evan's index (0.4 vs. 0.36, p<0.01) and the median diameter of the third ventricle (1.35 vs. 0.76, p<0.01) were statistically different between the two measurements. The preoperative length of the syrinx did not change significantly compared with the postoperative (5 vs. 1; p=0.052); nevertheless, the median transverse diameter of the syrinx did improve significantly after the surgery (0.75 vs. 0.32, p=0.03).

CONCLUSIONS

Our study supports ETV's safety and effectiveness for managing children with CSF disorders, ventriculomegaly, and associated CIM.

Suppression of TGFβR-Smad3 pathway alleviates the syrinx induced by syringomyelia

BACKGROUND

Syringomyelia is a cerebrospinal fluid (CSF) disorder resulted in separation of pain and temperature, dilation of central canal and formation of syrinx in central canal. It is unclear about mechanisms of the dilation and syrinx formation. We aimed to investigate roles of ependymal cells lining central canal on the dilation, trying to reduce syrinx formation in central canal.

METHODS

We employed 78 Sprague-Dawley (SD) rats totally with syringomyelia to detect the contribution of ependymal cells to the dilation of central canal. Immunofluorescence was used to examine the activation of ependymal cells in 54 syringomyelia rat models. BrdU was used to indicate the proliferation of ependymal cells through intraperitoneal administration in 6 syringomyelia rat models. 18 rats with syringomyelia were injected with SIS3, an inhibitor of TGFβR-Smad3, and rats injected with DMSO  were used as control. Among the 18 rats, 12 rats were used for observation of syrinx following SIS3 or DMSO administration by using magnetic resonance imaging (MRI) on day 14 and day 30 under syringomyelia without decompression. All the data were expressed as mean ± standard deviation (mean ± SD). Differences between groups were compared using the two-tailed Student's t-test or ANOVA. Differences were considered significant when *p < 0.05.

RESULTS

Our study showed the dilation and protrusions of central canal on day 5 and enlargement from day 14 after syringomyelia induction in rats with activation of ependymal cells lining central canal. Moreover, the ependymal cells contributed to protrusion formation possibly through migration along with central canal. Furthermore, suppression of TGFβR-Smad3 which was crucial for migration reversed the size of syrnix in central canal without treatment of decompression, suggesting TGFβR-Smad3 signal might be key for dilation of central canal and formation of syrinx.

CONCLUSIONS

The size of syrinx was decreased after SIS3 administration without decompression. Our study depicted the mechanisms of syrinx formation and suggested TGFβR-Smad3 signal might be key for dilation of central canal and formation of syrinx.

Above-The-Hairline Suboccipital Transverse Approach for the Treatment of Chiari I Malformation

BACKGROUND

Chiari I malformation is a common pediatric neurosurgical disorder with an established treatment paradigm. Posterior fossa decompression and duraplasty (PFDD) is associated with symptom improvement but it carries postoperative risk, particularly cerebrospinal fluid (CSF) leak and wound complications. In addition, the cosmetic outcomes of PFDD have been overlooked in the literature.

OBJECTIVE

To describe a novel approach for PFDD in which the transverse surgical incision is completely hidden above the hairline and to report early outcomes in a prospective patient cohort.

METHODS

Clinical and cosmetic outcomes were recorded for 15 consecutive pediatric patients who underwent PFDD for Chiari I malformation via the above-the-hairline transverse suboccipital approach.

RESULTS

The median clinical follow-up time was 6 months (range 1-12 months), and the majority of patients experienced significant improvement of their preoperative symptoms. Three patients (20%) experienced complications associated with surgery, which included injury to the greater occipital nerve, CSF hypotension and subfascial pseudomeningocele, and superficial wound dehiscence that resolved spontaneously with oral antibiotics. Zero patients (0%) returned to the operating room for persistent CSF leak, deep wound infection, or revision decompression. An excellent cosmetic outcome was achieved in 12 patients (80%). No patient had a poor cosmetic outcome.

CONCLUSION

The above-the-hairline transverse suboccipital approach for PFDD in patients with Chiari I malformation offers favorable cosmetic outcomes and fascial closure while permitting adequate decompression.

Biochemical profile of human infant cerebrospinal fluid in intraventricular hemorrhage and post-hemorrhagic hydrocephalus of prematurity

Background

Intraventricular hemorrhage (IVH) and post-hemorrhagic hydrocephalus (PHH) have a complex pathophysiology involving inflammatory response, ventricular zone and cell–cell junction disruption, and choroid-plexus (ChP) hypersecretion. Increased cerebrospinal fluid (CSF) cytokines, extracellular matrix proteins, and blood metabolites have been noted in IVH/PHH, but osmolality and electrolyte disturbances have not been evaluated in human infants with these conditions. We hypothesized that CSF total protein, osmolality, electrolytes, and immune cells increase in PHH.

Methods

CSF samples were obtained from lumbar punctures of control infants and infants with IVH prior to the development of PHH and any neurosurgical intervention. Osmolality, total protein, and electrolytes were measured in 52 infants (18 controls, 10 low grade (LG) IVH, 13 high grade (HG) IVH, and 11 PHH). Serum electrolyte concentrations, and CSF and serum cell counts within 1-day of clinical sampling were obtained from clinical charts. Frontal occipital horn ratio (FOR) was measured for estimating the degree of ventriculomegaly. Dunn or Tukey’s post-test ANOVA analysis were used for pair-wise comparisons.

Results

CSF osmolality, sodium, potassium, and chloride were elevated in PHH compared to control (p = 0.012 − < 0.0001), LGIVH (p = 0.023 − < 0.0001), and HGIVH (p = 0.015 − 0.0003), while magnesium and calcium levels were higher compared to control (p = 0.031) and LGIVH (p = 0.041). CSF total protein was higher in both HGIVH and PHH compared to control (p = 0.0009 and 0.0006 respectively) and LGIVH (p = 0.034 and 0.028 respectively). These differences were not reflected in serum electrolyte concentrations nor calculated osmolality across the groups. However, quantitatively, CSF sodium and chloride contributed 86% of CSF osmolality change between control and PHH; and CSF osmolality positively correlated with CSF sodium (r, p = 0.55,0.0015), potassium (r, p = 0.51,0.0041), chloride (r, p = 0.60,0.0004), but not total protein across the entire patient cohort. CSF total cells (p = 0.012), total nucleated cells (p = 0.0005), and percent monocyte (p = 0.016) were elevated in PHH compared to control. Serum white blood cell count increased in PHH compared to control (p = 0.042) but there were no differences in serum cell differential across groups. CSF total nucleated cells also positively correlated with CSF osmolality, sodium, potassium, and total protein (p = 0.025 − 0.0008) in the whole cohort.

Conclusions

CSF osmolality increased in PHH, largely driven by electrolyte changes rather than protein levels. However, serum electrolytes levels were unchanged across groups. CSF osmolality and electrolyte changes were correlated with CSF total nucleated cells which were also increased in PHH, further suggesting PHH is a neuro-inflammatory condition.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12987-021-00295-8.

Outcomes for various dural graft materials after posterior fossa decompression with duraplasty for Chiari malformation type I: a systematic review and meta-analysis

OBJECTIVE

Posterior fossa decompression with duraplasty (PFDD) is often used for Chiari malformation type I (CM-I), but outcomes associated with different dural graft materials are not well characterized. In this meta-analysis, the authors examined complication rates and outcomes after PFDD for CM-I for autografts and four types of nonautologous grafts.

METHODS

A literature search of numerous electronic databases (Ovid Medline, Embase, Scopus, Cochrane Database of Systematic Reviews, Cochrane Central Register of Controlled Trials, Database of Abstracts of Reviews of Effects, Health Technology Assessment Database, NHS Economic Evaluation Database, and ClinicalTrials.gov) was performed to identify articles detailing complications for dural graft materials after PFDD. Whenever available, data were also extracted regarding the need for revision surgery, symptom changes after PFDD, and syrinx size changes after PFDD. All searches were compliant with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA), Institute of Medicine, Standards for Systematic Reviews, Cochrane Handbook for Systematic Reviews of Interventions, and Peer Review of Electronic Search Strategies guidelines. There were no exclusion criteria based on patient age or presence or absence of syringomyelia.

RESULTS

The current evidence surrounding outcomes for various dural graft materials was found to be of low or very low quality. Twenty-seven studies were included, encompassing 1461 patients. Five types of dural graft materials were included: autograft (n = 404, 27.6%), synthetic (n = 272, 18.6%), bovine pericardium (n = 181, 12.4%), collagen-based (n = 397, 27.2%), and allograft (n = 207, 14.2%). Autograft was associated with a significantly lower rate of pseudomeningocele compared to collagen-based grafts, allografts, and nonautologous grafts in aggregate. Autograft was also associated with the lowest rates of aseptic meningitis, infectious meningitis, and need for revision PFDD, though these associations did not reach statistical significance. No other graft comparisons yielded significant results. Autograft and nonautologous graft materials yielded similar rates of revision surgery and produced similar improvements in postoperative symptoms and syrinx size.

CONCLUSIONS

Autograft was the dural graft material that most frequently had the lowest rate of complications and was associated with significantly lower rates of pseudomeningocele compared to collagen-based graft, allograft, and nonautologous graft materials. Autografts and nonautologous grafts yielded similar outcomes for revision surgery, symptoms, and syrinx size. Large prospective studies comparing different graft materials are needed to accurately and precisely characterize outcomes for individual graft types.

Extradural decompression versus duraplasty in Chiari malformation type I with syrinx: outcomes on scoliosis from the Park-Reeves Syringomyelia Research Consortium

OBJECTIVE

Scoliosis is common in patients with Chiari malformation type I (CM-I)-associated syringomyelia. While it is known that treatment with posterior fossa decompression (PFD) may reduce the progression of scoliosis, it is unknown if decompression with duraplasty is superior to extradural decompression.

METHODS

A large multicenter retrospective and prospective registry of 1257 pediatric patients with CM-I (tonsils ≥ 5 mm below the foramen magnum) and syrinx (≥ 3 mm in axial width) was reviewed for patients with scoliosis who underwent PFD with or without duraplasty.

RESULTS

In total, 422 patients who underwent PFD had a clinical diagnosis of scoliosis. Of these patients, 346 underwent duraplasty, 51 received extradural decompression alone, and 25 were excluded because no data were available on the type of PFD. The mean clinical follow-up was 2.6 years. Overall, there was no difference in subsequent occurrence of fusion or proportion of patients with curve progression between those with and those without a duraplasty. However, after controlling for age, sex, preoperative curve magnitude, syrinx length, syrinx width, and holocord syrinx, extradural decompression was associated with curve progression > 10°, but not increased occurrence of fusion. Older age at PFD and larger preoperative curve magnitude were independently associated with subsequent occurrence of fusion. Greater syrinx reduction after PFD of either type was associated with decreased occurrence of fusion.

CONCLUSIONS

In patients with CM-I, syrinx, and scoliosis undergoing PFD, there was no difference in subsequent occurrence of surgical correction of scoliosis between those receiving a duraplasty and those with an extradural decompression. However, after controlling for preoperative factors including age, syrinx characteristics, and curve magnitude, patients treated with duraplasty were less likely to have curve progression than patients treated with extradural decompression. Further study is needed to evaluate the role of duraplasty in curve stabilization after PFD.

Rare and de novo coding variants in chromodomain genes in Chiari I malformation

Chiari I malformation (CM1), the displacement of the cerebellum through the foramen magnum into the spinal canal, is one of the most common pediatric neurological conditions. Individuals with CM1 can present with neurological symptoms, including severe headaches and sensory or motor deficits, often as a consequence of brainstem compression or syringomyelia (SM). We conducted whole-exome sequencing (WES) on 668 CM1 probands and 232 family members and performed gene-burden and de novo enrichment analyses. A significant enrichment of rare and de novo non-synonymous variants in chromodomain (CHD) genes was observed among individuals with CM1 (combined p = 2.4 × 10-10), including 3 de novo loss-of-function variants in CHD8 (LOF enrichment p = 1.9 × 10-10) and a significant burden of rare transmitted variants in CHD3 (p = 1.8 × 10-6). Overall, individuals with CM1 were found to have significantly increased head circumference (p = 2.6 × 10-9), with many harboring CHD rare variants having macrocephaly. Finally, haploinsufficiency for chd8 in zebrafish led to macrocephaly and posterior hindbrain displacement reminiscent of CM1. These results implicate chromodomain genes and excessive brain growth in CM1 pathogenesis.

Chiari Malformation Type 1 and Syringomyelia in a Patient With Prior Surgically-Treated Sagittal Synostosis Effectively Treated With Posterior Cranial Vault Distraction Osteogenesis

ABSTRACT

The presenting report describes the use of a posterior cranial vault distraction procedure in resolving a Chiari malformation with associated syringomyelia following a surgically-treated nonsyndromic craniosynostosis. Chiari malformations are typically treated with posterior fossa decompression with or without expansion duraplasty. The objective of this report is to describe the effectiveness in resolving both Chiari malformation and secondary syringomyelia with posterior cranial vault distraction osteogenesis. A 5-year-old male, with a history of surgery for sagittal synostosis during infancy, presented with daily severe headaches and dysesthesias in the hands and feet. Imaging demonstrated a copper-beaten calvarium and a Chiari 1 malformation with a 7 mm diameter C4-T1 syrinx. He underwent posterior cranial vault distraction osteogenesis over 3 months to increase his intracranial volume. The patients' headaches improved significantly, and his dysesthesias resolved postoperatively. A magnetic resonance imaging performed 7 months after completion of distraction demonstrated resolution of the Chiari malformation and decompression of his syrinx. A computed tomography scan at 9 months postdistraction showed resolution of the copper-beaten calvarium. Patients with a history of craniosynostosis can develop inadequate cranial volume over time due to abnormal skull growth, leading to secondary Chiari malformation with or without syringomyelia. Posterior vault distraction is an effective strategy to address these conditions and can be employed later in childhood to treat the underlying pathology. The mechanism potentially expands both calvarium and dura, which in turn addresses both the Chiari malformation and secondary syringomyelia.

Prevalence and Impact of Underlying Diagnosis and Comorbidities on Chiari 1 Malformation

BACKGROUND

Chiari malformation type 1 affects approximately one in 1,000 people symptomatically, although one in 100 meet radiological criteria, making it a common neurological disorder. The diagnosis of underlying conditions has become more sophisticated, and new radiological markers of disease have been described. We sought to determine the prevalence and impact of additional comorbidities and underlying diagnoses in patients with Chiari malformation type 1 on symptomatology and surgical treatment.

METHODS

A retrospective review of 612 pediatric patients with a Chiari malformation type 1 diagnosis and imaging data evaluated between 2008 and 2018 was performed. Because of extensive clinical heterogeneity, patients were separated into four categories based on their primary comorbidities (nonsyndromic, central nervous system, skeletal, and multiple congenital anomalies) to identify associations with age of onset, radiographic measurements, syringomyelia, and surgical treatment.

RESULTS

The largest group had nonsyndromic Chiari malformation type 1 (70%) and the latest age at diagnosis of any group. In the syndromic group, 6% were diagnosed with a known genetic abnormality, with overgrowth syndromes being the most common. Patients with multiple congenital anomalies had the earliest Chiari malformation type 1 onset, the most severe tonsillar ectopia and obex position, and were overrepresented among surgical cases. Although there were no statistically significant differences between groups and rates of syrinx, we observed differences in individual diagnoses.

CONCLUSION

The underlying diagnoses and presence of comorbidities in patients with Chiari malformation type 1 impacts rates of syringomyelia and surgery. Although most Chiari malformation type 1 cases are nonsyndromic, clinical evaluation of growth parameters, scoliosis, and joint hypermobility should be routine for all patients as they are useful to determine syringomyelia risk and may impact treatment.

Ventrolateral Tonsillar Position Defines Novel Chiari 0.5 Classification

BACKGROUND

Cervicomedullary compression in young children has been described in the context of Chiari type 1 malformation, with symptoms associated with the extent of tonsillar herniation below McRae line. Historically, Chiari type 1 malformation has been defined by tonsillar herniation of at least 5 mm. However, in certain populations, including very young children, Chiari symptoms may be present without this finding. A new Chiari classification is thus necessary.

METHODS

Cases involving patients up to 5 years of age evaluated for possible posterior fossa decompression were retrospectively reviewed. Preoperative symptoms, magnetic resonance imaging findings, surgical management, and short- and long-term outcome and follow-up were recorded. Tonsillar descent and presence of ventral herniation (VH) were recorded. We define VH as the tonsils crossing a line that bisects the caudal medulla at the level of the foramen magnum, thus creating a novel entity, Chiari type 0.5 malformation. Patients with ventrally herniated tonsils were compared with patients exhibiting more typical Chiari morphology.

RESULTS

Of 41 cases retrospectively reviewed, 20 met criteria for VH. These differed from cases without VH because of the predominance of medullary symptoms. In the VH cohort, 11 patients underwent surgical decompression with symptom resolution; 9 were initially managed conservatively, but 3 subsequently required surgery.

CONCLUSIONS

We define a novel Chiari entity, Chiari type 0.5 malformation, characterized by ventral tonsillar wrapping around the medulla in young children in the absence of classic Chiari type 1 malformation imaging findings. These patients are more likely to present with medullary symptoms than patients without VH. They are also more likely to require surgical decompression and respond favorably to intervention.

Risk Factors Portending Extended Length of Stay After Suboccipital Decompression for Adult Chiari I Malformation

OBJECTIVE

For adult patients undergoing surgical decompression for Chiari malformation type I (CM-I), the patient-level factors that influence extended length of stay (LOS) are relatively unknown. The aim of this study was to investigate the impact of patient-baseline comorbidities, demographics, and postoperative complications on extended LOS after intervention after adult CM-I decompression surgery.

METHODS

A retrospective cohort study using the National Inpatient Sample years 2010-2014 was performed. Adults (≥18 years) with a primary diagnosis of CM-I undergoing surgical decompression were identified. Weighted patient demographics, comorbidities, complications, LOS, disposition, and total cost were recorded. A multivariate logistic regression was used to determine the odds ratio for risk-adjusted LOS.

RESULTS

A total of 29,961 patients were identified, 6802 of whom (22.7%) had extended LOS. The extended LOS cohort had a significantly greater overall complication rate (normal LOS, 10.6% vs. extended LOS, 29.1%; P < 0.001) and total cost (normal LOS, $14,959 ± $6037 vs. extended LOS, $25,324 ± $21,629; P < 0.001) compared with the normal LOS cohort. On multivariate logistic regression, black race, income quartiles, private insurance, obstructive hydrocephalus, lack of coordination, fluid and electrolyte disorders, and paralysis were all independently associated with extended LOS. Additional duraplasty (P = 0.132) was not significantly associated with extended LOS after adjusting for other variables. The odds ratio for extended LOS was 2.07 (95% confidence interval, 1.59-2.71) for patients with 1 complication and 9.47 (95% confidence interval, 5.86-15.30) for patients with >1 complication.

CONCLUSIONS

Our study shows that extended LOS after adult CM-I decompression surgery may be influenced by multiple patient-level factors.

Outcomes and complications for individual neurosurgeons for the treatment of Chiari I malformation at a children's hospital

PURPOSE

The aim of this study was to evaluate the outcomes and complications for individual surgeons at British Columbia Children's Hospital for the treatment of Chiari I Malformation (CMI) in children.

METHODS

This was a retrospective review of patients with CMI who had surgery from 1986 to 2015. We assessed the Chicago Chiari Outcome Scores (CCOS) and complication rates by surgeon.

RESULTS

Seventy patients, 38 males and 32 females, underwent posterior fossa decompression including 14 extradural and 56 intradural approaches. Syringomyelia was present in 74.3%. Most syringomyelia improved with no difference between intradural and extradural surgeries. After initial surgery, 13 patients (18.6%) had complications including 2/14 (14.3%) of extradural and 11/56 (19.6%) of intradural surgeries. Two patients required surgical intervention for complications whereas 11 had transient complications. The complication rate by surgeon ranged from 11 to 20% for extradural (2 surgeons only) and 10.5 to 40% for intradural surgeries (4 surgeons). The CCOS ranged from 12 to 15 for extradural and 6 to 16 for intradural. The CCOS ranges for surgeons 1 and 2 were 12-15 and 13-15 respectively for extradural. The CCOS ranges for surgeons 1, 2, 3, and 4 were 12-16, 6-15, 12-16, and 12-16 respectively for intradural. Thirteen patients had a second surgery for CMI. The final CCOS was good in 86% and moderate in 14%.

CONCLUSION

There was variability in surgeries performed at BCCH by different surgeons, with variations in CCOS and complication rates. This information is important during decision making, consent process, and for quality improvement.

Chiari type I and hydrocephalus

PURPOSE

The association between Chiari type I malformation (CIM) and hydrocephalus raises a great interest because of the still unclear pathogenesis and the management implications. The goal of this paper is to review the theories on the cause-effect mechanisms of such a relationship and to analyze the results of the management of this condition.

METHODS

A review of the literature has been performed, focusing on the articles specifically addressing the problem of CIM and hydrocephalus and on the series reporting about its treatment. Also, the personal authors' experience is briefly discussed.

RESULTS

As far as the pathogenesis is concerned, it seems clear that raised intracranial pressure due to hydrocephalus can cause a transient and reversible tonsillar caudal ectopia ("pressure from above" hypothesis), which is something different from CIM. A "complex" hypothesis, on the other hand, can explain the occurrence of hydrocephalus and CIM because of the venous engorgement resulting from the hypoplasia of the posterior cranial fossa (PCF) and the occlusion of the jugular foramina, leading to cerebellar edema (CIM) and CSF hypo-resorption (hydrocephalus). Nevertheless, such a mechanism can be advocated only in a minority of cases (syndromic craniosynostosis). In non-syndromic CIM subjects, the presence of hydrocephalus could be explained by an occlusion of the basal CSF pathways, which would occur completely in a minority of cases (only 7-10% of CIM patients show hydrocephalus) while it would be partial in the remaining cases (no hydrocephalus). This hypothesis still needs to be demonstrated. As far as the management is concerned, the strategy to treat the hydrocephalus first is commonly accepted. Because of the "obstructive" origin of CIM-related hydrocephalus, the use of endoscopic third ventriculostomy (ETV) is straightforward. Actually, the analysis of the literature, concerning 63 cases reported so far, reveals very high success rates of ETV in treating hydrocephalus (90.5%), CIM (78.5%), and syringomyelia symptoms (76%) as well as in giving a radiological improvement of both CIM (74%) and syringomyelia (89%). The failures of ETV were not attributable to CIM or syringomyelia. Only 11% of cases required PCF decompression after ETV.

CONCLUSIONS

The association between CIM and hydrocephalus probably results from different, multifactorial, and not yet completely understood mechanisms, which place the affected patients in a peculiar subgroup among those constituting the heterogeneous CIM population. ETV is confirmed as the best first approach for this subset of patients.

Chiari 1 malformation and raised intracranial pressure

BACKGROUND

The pathophysiology of Chiari 1 malformation (CM1) is inextricably related to intracranial pressure (ICP). The characteristic cerebellar tonsil herniation at the foramen magnum may either cause raised ICP by disturbing CSF flow (as observed in idiopathic CM1) or may itself be the effect of raised ICP (as observed in acquired CM1). Distinguishing between these two phenomena, therefore, is of paramount importance in successfully alleviating the symptoms of the condition and preventing serious complications.

OBJECTIVES

In this article, we discuss the pathophysiology of raised ICP in CM1 and review the current evidence for its investigation and treatment. We also share our own clinical experience which investigates the utility of ICP monitoring in a series of 26 children with CM1.

Posterior fossa decompression for Chiari malformation type I: clinical and radiological presentation, outcome and complications in a retrospective series of 105 procedures

OBJECTIVE

Determining clinical and radiological characteristics, complication rates and outcome for patients undergoing posterior fossa decompression (PFD) and duraplasty for Chiari malformation type I (CM-I).

METHODS AND MATERIALS

Retrospective, single-university hospital study of all PFDs for CM-I between January 1995 and December 2016.

RESULTS

PFD was performed in 105 patients with CM-I (n = 105), of whom 62 suffered from associated syringomyelia and 37 were pediatric cases. There was a female preponderance in the syringomyelia, non-syringomyelia, pediatric and adult groups (62.9%, 65.1%, 54.1% and 69.1%, respectively). Mean age at diagnosis was higher in the syringomyelia group (32.3 versus 26.9 years, p = 0.06) and in both groups delay for diagnosis was long (33.4 and 47.1 months, p = 0.50). Headache during Valsalva maneuver and on exertion was significantly more present in the non-syringomyelia group (27.9% versus 16.1%, p < 0.0001 and 39.5% versus 11.3%, p = 0.0009); cranial nerve dysfunction and cerebellar signs did not differ significantly (p = 0.07 and p = 0.53). Spinal cord syndrome was significantly more present in the syringomyelia group (72.6% versus 25.6%, p < 0.0001). Scoliosis was present in five patients, of whom four had syringomyelia. Duraplasty was performed in 101 surgeries. For 100 patients, PFD was the primary treatment of CM-I; 2 patients had previously undergone syrinx drainage and 3 ventriculoperitoneal shunting for hydrocephalus. Only one patient presented with hydrocephalus. Duraplasty (n = 101) was complicated by CSF leak in 4.0% (n = 4), symptomatic pseudomeningocele in 4.0% (n = 4), aseptic meningitis in 2.0% (n = 2) and hydrocephalus in 1.0% (n = 1). Osseous decompression without duraplasty was performed in only four highly selected patients, not allowing a comparative analysis with duraplasty. Post-operative symptom improvement is reported for 67.3% of all patients and stabilization of symptoms in 23.9%. Symptom improvement was significantly more frequent in the non-syringomyelia group (p = 0.03). Outcome seemed similarly good in the pediatric and the adult groups.

CONCLUSION

PFD performed with duraplasty is a safe procedure. The majority of patients do report symptom stabilization or improvement. Non-syringomyelia patients reported significantly more frequent improvement of clinical symptoms.

Outcomes and resource utilization in surgery for Chiari I malformation in a national network of children's hospitals

INTRODUCTION

Chiari malformation type 1 (CM-1) is a common congenital or acquired malformation of the posterior fossa. We aimed to characterize preoperative risk factors, perioperative complications, and postoperative outcomes related to CM-1 surgery in pediatric populations across a nationwide network of pediatric hospitals in the United States (US).

METHODS

The Children's Hospital Association's Pediatric Health Information System (PHIS) database was used to examine patients < 21 years old in the US-based nationwide database who underwent inpatient surgery for CM-1 from 2007 to 2015. Data analyzed included patient characteristics, preoperative comorbidities, perioperative outcomes, short-term postoperative surgical and medical complications, and healthcare resource utilization.

RESULTS

Among the 5976 patients identified, those age 0-4 years had higher medical and surgical complication rates compared to older patients. Those with pre-existing comorbidity of hydrocephalus had higher odds of 30- and 90-day medical and surgical complications. Those with any complications at 90 days had an increased length of stay and higher healthcare costs compared to those without complications. 6.88% of complications were surgical and 1.67% medical. Patients with medical complications had the longer mean stay and associated costs compared to those with surgical complications (13 vs. 6.9 at 95% CI, and $71,300-94,500 vs. $110,400-195,000 at 95% CI).

CONCLUSIONS

Use of a US-based national children's hospital database presents outcomes and resource utilization from a multi-institutional, real-world experience in pediatric hospitals. There was a higher risk of perioperative complications in younger patients and those with pre-existing comorbidities, namely hydrocephalus. Understanding preoperative risk factors, perioperative complications, and postoperative outcomes, as well as healthcare utilization and costs, can help target areas for improvement and guide preoperative counseling and risk stratification.

Clinical deterioration despite syringomyelia resolution after successful foramen magnum decompression for Chiari malformation - Case series

INTRODUCTION

Neurosurgical treatment is recommended for symptomatic syringomyelia and the post-operative radiological resolution of the syringomyelia is associated with an improvement or at least stability of the patient's pre-operative symptoms.

METHODS

We reviewed syringomyelia treatment in our centre over the last five years for clinical outcome, surgical complications, post operative MRI and long term symptom resolution.

RESULTS

50 cases of symptomatic syringomyelia underwent foramen magnum decompression and expansile watertight duroplasty. While the outcomes for majority are similar to what published in literature, three of them developed typical syringomyelia symptoms after initial good recovery and radiological resolution of syrinx.

CONCLUSION

Syringomyelia symptoms may appear or worsen following successful surgical treatment and radiological resolution of syrinx and it is important to counsel young people and their family regarding this.

Unexpected Progression of Tonsillar Herniation in Two Pediatric Cases with Chiari Malformation Type I and Review of the Literature

BACKGROUND

Chiari malformation type 1 (CM-1) is a generally congenital, rarely acquired disease characterized with 5 mm or more displacement of cerebellar tonsils through foramen magnum.

METHODS

Here, we report about 2 patients with CM-1 progressed in the degree of tonsillar herniation from our clinic, whereas increasing in prolapse of tonsillar herniation after diagnosis is extremely uncommon.

RESULTS

The first patient aged 17 years was diagnosed with CM-1 in 2009 and was operated due to progression of 5 mm radiologically and worsening symptoms in 2014. The second 5-month-old patient initially showed just low-settled tonsillar localization at the borderline, then it descended by 2 cm when the patient reached 3 years of age, yet could not be operated because of parents' objection.

CONCLUSION

Due to lack of reports on increasing tonsillar descent in the literature, these case reports will contribute to natural history and management of CM-1.

Big Data Research in Pediatric Neurosurgery: Content, Statistical Output, and Bibliometric Analysis

BACKGROUND/AIMS

We sought to describe pediatric "big data" publications since 2000, their statistical output, and clinical implications.

METHODS

We searched 4 major North American neurosurgical journals for articles utilizing non-neurosurgery-specific databases for clinical pediatric neurosurgery research. Articles were analyzed for descriptive and statistical information. We analyzed effect sizes (ESs), confidence intervals (CIs), and p values for clinical relevance. A bibliometric analysis was performed using several key citation metrics.

RESULTS

We identified 74 articles, which constituted 1.7% of all pediatric articles (n = 4,436) published, with an exponential increase after 2013 (53/74, 72%). The Healthcare Cost and Utilization Project (HCUP) databases were most frequently utilized (n = 33); hydrocephalus (n = 19) was the most common study topic. The statistical output (n = 49 studies with 464 ESs, 456 CIs, and 389 p values) demonstrated that the majority of the ESs (253/464, 55%) were categorized as small; half or more of the CI spread (CIS) values and p values were high (274/456, 60%) and very strong (195/389, 50%), respectively. Associations with a combination of medium-to-large ESs (i.e., magnitude of difference), medium-to-high CISs (i.e., precision), and strong-to-very strong p values comprised only 20% (75/381) of the reported ESs. The total number of citations for the 74 articles was 1,115 (range per article, 0-129), with the median number of citations per article being 8.5. Four studies had > 50 citations, and 2 of them had > 100 citations. The calculated h-index was 16, h-core citations were 718, the e-index was 21.5, and the Google i10-index was 34.

CONCLUSIONS

There has been a dramatic increase in the use of "big data" in the pediatric neurosurgical literature. Reported associations that may, as a group, be of greatest interest to practitioners represented only 20% of the total output from these publications. Citations were weighted towards a few highly cited publications.

Current management of pediatric chiari type 1 malformations

OBJECTIVES

Pediatric Chiari Type 1 Malformations (CM1) are commonly referred for neurosurgical opinion. The ideal management in children regarding surgical and radiographic decision making is not clearly delineated.

PATIENTS AND METHODS

We retrospectively reviewed our cohort of patients age 18 years and younger referred to a single neurosurgeon for CM1. Baseline MRIs of the spine were obtained. Non-operative patients had repeat imaging at 6-12 months. Patients who underwent an operation (decompression with/without duraplasty) had repeat imaging at 6 months.

RESULTS

One hundred and thirty-two patients with mean age of 10 years met inclusion criteria. All patients had post-operative symptomatic improvement. We identified 26 patients with syrinx, 8 with scoliosis, 3 with hydrocephalus, and one had tethered cord. The average tonsillar descent was 8.1 mm in the non-operative group and 11.9 mm in the operative group. Ninety-five patients were managed conservatively (72%). Thirty-seven were offered surgery (28%), and 33 patients underwent intervention; 21 with duraplasty (64%) and 12 without (36%).

CONCLUSIONS

Pediatric patients with CM1 require both clinical and radiographic follow-up. Duraplasty may be performed if decompression fails to relieve symptomatology, but is not always needed. CM1 continues to present a challenge in surgical decision making. Adhering to a treatment paradigm may help alleviate difficult decision-making.

Predictors of mortality for preterm infants with intraventricular hemorrhage: a population-based study

PURPOSE

The goal of this longitudinal, population-level study was to examine factors affecting mortality in preterm infants with intraventricular hemorrhage (IVH).

METHODS

The study examined patients who were born at 36 weeks estimated gestational age (EGA) or less with a diagnosis of IVH between the years 2005 and 2014 using data from the New York and Nebraska State Inpatient Databases. Potential predictors for mortality were investigated with multivariable survival analysis.

RESULTS

The cohort included 7437 preterm infants with IVH. All-cause inpatient mortality occurred in 746 (10.0%). The majority of deaths were in infants born at less than 25 weeks EGA (378 or 50.7%) and with birthweight less than 750 g (459 or 61.5%). Mortality was highest for children with grade IV IVH (306/848 or 36.1%), followed by grades III (203/955 or 21.3%), II (103/1328 or 7.8%), and I (134/4306 or 3.1%). Hydrocephalus was diagnosed within 6 months in 627 (8.4%) patients, with cerebrospinal fluid shunts required in 237 (3.2%). Shunts were eventually revised in 122 (51.5% of shunts), and 43 (18.1%) had infections. Multivariable Cox survival analyses found male sex (HR 1.3 [95% CI 1.1-1.5]), Asian race (HR 1.5 [1.1-2.2]), lower EGA (HR 9.9 [6.3-15.5] for < 25 weeks), higher IVH grade (HR 6.1 [4.9-7.6] for grade IV), gastrostomy (HR 4.0 [2.0-7.7]), tracheostomy (HR 3.5 [1.7-7.1]), and shunt infection (HR 3.2 [1.0-9.9]) to be independently associated with increased mortality risk.

CONCLUSIONS

This database is the first of its kind assembled for population-based investigations of long-term neurosurgical outcomes in preterm infants with IVH.

Quality of Life After Combined Endonasal Endoscopic Odontoidectomy and Posterior Suboccipital Decompression and Fusion

BACKGROUND

Basilar invagination can result from systemic diseases that can weaken structural integrity of the craniocervical junction. Definitive treatment often requires ventral decompression and posterior decompression and fusion. Endonasal odontoidectomy is a relatively new minimal access procedure; quality of life (QOL) after this procedure has not been reported.

METHODS

We reviewed a consecutive database of endonasal odontoidectomy cases and identified patients having posterior decompression and fusion. Two QOL questionnaires were administered postoperatively: Sino-Nasal Outcome Test and 36-Item Short Form Survey. Comparisons with other endonasal or Chiari procedures were performed.

RESULTS

The study comprised 14 patients; 79% had Chiari malformation in addition to basilar invagination. Mean follow-up was 17.2 months. Symptomatic improvement occurred in 78.6% after surgery. Average postoperative Sino-Nasal Outcome Test scores were 39.2 ± 17.93, with worst scores in areas related to fatigue and sleep patterns but not nasal function. 36-Item Short Form Survey scores were lower in areas of physical function and general health but better for emotional health and pain. Compared with patients undergoing Chiari malformation surgery without endonasal odontoid resection or fusion, patients undergoing odontoidectomy had higher QOL in areas of role emotional, emotional well-being, and pain but worse QOL in general health and role physical.

CONCLUSIONS

Patients undergoing posterior decompression and fusion with endonasal odontoidectomy do well after surgery with respect to nasal function and emotional health. Patients who also have severe basilar invagination associated with systemic diseases demonstrate reduced QOL after surgery in areas of physical function and sleep leading to fatigue, irritability, and concentration difficulty, likely related to their systemic disease.

Thirty-day outcomes in pediatric epilepsy surgery

PURPOSE

The aim of this study was to use the multicenter American College of Surgeons National Surgical Quality Improvement Program-Pediatric (NSQIP-P) to evaluate and identify risk factors for 30-day adverse events in children undergoing epilepsy surgery.

METHODS

Using the 2015 NSQIP-P database, we identified children (age 0-18 years) undergoing pediatric epilepsy surgery and analyzed NSQIP-defined complications, unplanned reoperations, and unplanned readmissions. Multivariable logistic regression analysis was performed using perioperative data to identify risk factors for adverse events within 30 days of the index procedure.

RESULTS

Two hundred eight pediatric patients undergoing epilepsy surgery were identified for the year 2015 in the NSQIP-P database. The majority of patients were male (51.8%) and white (72.9%). The median age was 10 years. Neurological and neuromuscular comorbidities were seen in 62.5% of patients. Surgical blood loss and transfusion was the most common overall NSQIP-defined event (15.7%) and was reported in 40% with hemispherectomy. Nineteen patients (6.8%) had an unplanned reoperation and 20 patients (7.1%) had an unplanned readmission. Multivariable logistic regression analysis showed that African American patients (OR 3.26, 95% CI 1.29-8.21, p = 0.01) and hemispherectomy (OR 3.05, 95% CI 1.4-6.65, p = 0.01) were independently associated with NSQIP-defined complications. Patients undergoing hemispherectomy (OR 4.11, 95% CI 1.48-11.42, p = 0.01) were also at significantly higher risk of unplanned readmission after pediatric epilepsy surgery.

CONCLUSIONS

Data from the 2015 NSQIP-P database showed that hemispherectomy was significantly associated with higher perioperative events in children undergoing epilepsy surgery. Quality improvement initiatives for hemispherectomy should target surgical blood loss and wound-related complications. Racial disparities in access to cranial pediatric epilepsy surgery and perioperative complications were also highlighted in the present study.

Chiari type I malformation of infants and toddlers

OBJECTIVES

Chiari I malformation has been a well-recognized clinical entity; however, its occurrence among infants and toddlers is unusual. Their clinical presentations may be different from other age groups due to their lack of effective verbal communication. The authors analyze their personal series of patients focusing on symptomatology and MRI characteristics. Treatment methods, results, and outcome are analyzed in order to identify appropriate surgical management among infants and toddlers with Chiari I malformation.

METHODS

The authors retrospectively reviewed 16 patients who were diagnosed and surgically treated between 2007 and 2014 during the first 3 years of life with minimum follow-up of 3 years. We focused on the presenting symptoms, magnetic resonance imaging findings, and surgical techniques used for posterior fossa decompression (PFD) and their postoperative outcome.

RESULTS

Twelve patients (75%) presented with signs of headaches such as irritability, inconsolable crying, head grabbing, and/or arching back. Ten patients (62.5%) presented with oropharyngeal and/or respiratory symptoms such as emesis, choking, gagging, snoring, sleep apnea, breathing pause, and/or vocal cord palsy. Only one patient had segmental cervical hydromyelia. At the first surgery, ten patients had PFD with dural scoring (Type 1 procedure), while six others had PFD with duraplasty (Type 2 procedure) with thermal reduction of the cerebellar tonsils in four. Following the first operation, all initially had varying degrees of symptomatic improvement; however, seven patients subsequently had symptomatic recurrence. Persistent crowding at the PFD site on the postoperative imaging indicated greater risk of recurrences in both Type 1 procedure and Type 2 procedure groups. Of seven patients who needed a second operation, fivewere after Type 1 procedure and the two were after Type 2 procedure. The difference of recurrence rates between these two groups is not significant. CSF-related complications occurred in 4 out of 11 patients who had Type 2 procedure (one after primary decompression and three after the second decompression for recurrence).

CONCLUSION

Young patients lacking effective verbal communication often present their Chiari I malformation differently from olderage groups. Behavioral changes indicative of headaches/irritability and oropharyngeal/respiratory symptoms are the primary presenting symptoms. The recurrence rate tends to be higher among the patients after Type 1 procedure (particularly those younger than 18 months) than after Type 2 procedure. We observed that duraplasty at primary or at redo PFD provides for better decompression and long-term outcome. However, one should keep it in mind that there is risk of CSF-related complications following duraplasty, particularly higher tendency after redo PFD.

Trends in surgical treatment of Chiari malformation Type I in the United States

OBJECTIVE The goal of this analysis was to define temporal and geographic trends in the surgical treatment of Chiari malformation Type I (CM-I) in a large, privately insured health care network. METHODS The authors examined de-identified insurance claims data from a large, privately insured health care network of over 58 million beneficiaries throughout the United States for the period between 2001 and 2014 for all patients undergoing surgical treatment of CM-I. Using a combination of International Classification of Diseases (ICD) diagnosis codes and Current Procedural Terminology (CPT) codes, the authors identified CM-I and associated diagnoses and procedures over a 14-year period, highlighting temporal and geographic trends in the performance of CM-I decompression (CMD) surgery as well as commonly associated procedures. RESULTS There were 2434 surgical procedures performed for CMD among the beneficiaries during the 14-year interval; 34% were performed in patients younger than 20 years of age. The rate of CMD increased 51% from the first half to the second half of the study period among younger patients (p < 0.001) and increased 28% among adult patients between 20 and 65 years of age (p < 0.001). A large sex difference was noted among adult patients; 78% of adult patients undergoing CMD were female compared with only 53% of the children. Pediatric patients undergoing CMD were more likely to be white with a higher household net worth. Regional variability was identified among rates of CMD as well. The average annual rate of surgery ranged from 0.8 surgeries per 100,000 insured person-years in the Pacific census division to 2.0 surgeries per 100,000 insured person-years in the East South Central census division. CONCLUSIONS Analysis of a large nationwide health care network showed recently increasing rates of CMD in children and adults over the past 14 years.

"Stealth cranioplasty:" A novel endeavor for symptomatic adult Chiari I patients with syringomyelia: Technical note, appraisal, and philosophical considerations

Aim and Objective:

In this article, we describe a novel technique of reconstruction of posterior fossa by cranioplasty with use of preshaped titanium mesh following posterior fossa decompression (PFD) for Chiari malformation type I (CMI) with syringomyelia (SM) in symptomatic adults.

Materials and Methods:

Eleven patients underwent limited PFD and expansive cranioplasty with preshaped titanium mesh, what we term as “Stealth Cranioplasty” (SCP), following arachnoid preserving duraplasty (APD) and hexagonal tenting of the duraplasty with the cranioplasty (HTDC) for the management of symptomatic adult CMI with SM. All these patients had syringes extending from 3 to >10 vertebral levels.

Results:

Seven male and four female symptomatic CMI adult patients, between age ranges of 22 and 44 years (mean 29.45 years), presented with different neurological symptoms related to CMI and SM for 6–84 months (mean 37.09 months). All the patients underwent PFD, APD followed by SCP and HTDC and were followed up for 7–54 months (mean 35.90 months). Of 11 patients, 8 patients improved according to the Chicago Chiari Outcome Scale (CCOS) with score of 13–15 while 3 patients remained unchanged with CCOS of 12, and there was no worsening. There was no complication related to Chiari surgery in any of the patients. All the patients had good reestablishment of cisterna magna. Two patients had marked reduction of syrinx while eight patients had moderate-to-mild reduction and one patient had no change of syrinx. None of the patients needed redo surgery.

Conclusion:

SCP is an effective, fruitful, and cost-effective technique for the management of symptomatic adult CMI with SM. This technique has the advantages of preventing complications and recurrences in addition to the improvement of symptoms by addressing the basic pathology.

Hospitalization Cost Model of Pediatric Surgical Treatment of Chiari Type 1 Malformation

OBJECTIVES

To develop a cost model for hospitalization costs of surgery among children with Chiari malformation type 1 (CM-1) and to examine risk factors for increased costs.

STUDY DESIGN

Data were extracted from the US National Healthcare Cost and Utilization Project 2009 Kids' Inpatient Database. The study cohort was comprised of patients aged 0-20 years who underwent CM-1 surgery. Patient charges were converted to costs by cost-to-charge ratios. Simple and multivariable generalized linear models were used to construct cost models and to determine factors associated with increased hospital costs of CM-1 surgery.

RESULTS

A total of 1075 patients were included. Median age was 11 years (IQR 5-16 years). Payers included public (32.9%) and private (61.5%) insurers. Median wage-adjusted cost and length-of-stay for CM-1 surgery were US $13 598 (IQR $10 475-$18 266) and 3 days (IQR 3-4 days). Higher costs were found at freestanding children's hospitals: average incremental-increased cost (AIIC) was US $5155 (95% CI $2067-$8749). Factors most associated with increased hospitalization costs were patients with device-dependent complex chronic conditions (AIIC $20 617, 95% CI $13 721-$29 026) and medical complications (AIIC $13 632, 95% CI $7163-$21 845). Neurologic and neuromuscular, metabolic, gastrointestinal, and other congenital genetic defect complex chronic conditions were also associated with higher hospital costs.

CONCLUSIONS

This study examined cost drivers for surgery for CM-1; the results may serve as a starting point in informing the development of financial risk models, such as bundled payments or prospective payment systems for these procedures. Beyond financial implications, the study identified specific risk factors associated with increased costs.

Thirty-day outcomes for posterior fossa decompression in children with Chiari type 1 malformation from the US NSQIP-Pediatric database

PURPOSE

The multicenter National Surgical Quality Improvement Program-Pediatric (NSQIP-P) database maintained by the American College of Surgeons was used to describe 30-day outcomes following Chiari type 1 decompression in children and to identify risk factors for readmission, reoperation, and perioperative complications.

METHODS

We identified patients aged 0-18 years who underwent posterior cranial fossa decompression for Chiari type 1 malformation in 2012, 2013, and 2014 in the NSQIP-Pediatric database. Multivariate regression analysis was performed using preoperative and perioperative data to determine risk factors for perioperative adverse events within 30 days of the index procedure.

RESULTS

We identified 1459 patients from the NSQIP-P database for the years 2012-2014. Fifty-five percent of the patients were female. Mean age was 9.8 years (median 10 years). Median operative time was 141 min (IQR 107-181 min). Postoperative complications were noted in 5.3 % and unplanned reoperations in 3.4 % of the patients. Postoperative ventriculoperitoneal shunt placement occurred in 0.9 % of the patients. Wound problems were the most common complication (3.8 % of all patients). Univariate analysis showed the following factors were associated with perioperative adverse events: longer operative times, hospital stay ≥5 days, hydrocephalus, and neurological, renal, and congenital comorbidities. On multivariate analysis, female sex (OR 1.46, 95 % CI 1.01-2.11), increased operative time (OR 1.01, 95 % CI 1.00-1.01), and hospital stay ≥5 days (OR 2.62, 95 % CI 1.55-4.43) were independent factors associated with perioperative adverse events.

CONCLUSION

The NSQIP-P database was used to describe surgical outcomes of posterior cranial fossa decompression in a US nationwide sample of 1459 children with Chiari type 1 malformation. The overall recorded adverse rate was low. Longer operative times and length of hospital stay ≥5 days during the index admission were associated with perioperative adverse events.

Chiari malformation Type I surgery in pediatric patients. Part 1: validation of an ICD-9-CM code search algorithm

OBJECTIVE Administrative billing data may facilitate large-scale assessments of treatment outcomes for pediatric Chiari malformation Type I (CM-I). Validated International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) code algorithms for identifying CM-I surgery are critical prerequisites for such studies but are currently only available for adults. The objective of this study was to validate two ICD-9-CM code algorithms using hospital billing data to identify pediatric patients undergoing CM-I decompression surgery. METHODS The authors retrospectively analyzed the validity of two ICD-9-CM code algorithms for identifying pediatric CM-I decompression surgery performed at 3 academic medical centers between 2001 and 2013. Algorithm 1 included any discharge diagnosis code of 348.4 (CM-I), as well as a procedure code of 01.24 (cranial decompression) or 03.09 (spinal decompression or laminectomy). Algorithm 2 restricted this group to the subset of patients with a primary discharge diagnosis of 348.4. The positive predictive value (PPV) and sensitivity of each algorithm were calculated. RESULTS Among 625 first-time admissions identified by Algorithm 1, the overall PPV for CM-I decompression was 92%. Among the 581 admissions identified by Algorithm 2, the PPV was 97%. The PPV for Algorithm 1 was lower in one center (84%) compared with the other centers (93%-94%), whereas the PPV of Algorithm 2 remained high (96%-98%) across all subgroups. The sensitivity of Algorithms 1 (91%) and 2 (89%) was very good and remained so across subgroups (82%-97%). CONCLUSIONS An ICD-9-CM algorithm requiring a primary diagnosis of CM-I has excellent PPV and very good sensitivity for identifying CM-I decompression surgery in pediatric patients. These results establish a basis for utilizing administrative billing data to assess pediatric CM-I treatment outcomes.