Complications and Resource Use Associated With Surgery for Chiari Malformation Type 1 in Adults: A Population Perspective

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.

Complication Avoidance in Chiari Malformation Surgery

Posterior fossa decompression for symptomatic Chiari malformation is an effective and frequently performed procedure, but it does carry risks of significant complications including cerebrospinal fluid leak and craniocervical instability. Patients sometimes do not improve or worsen after decompression, which may discourage neurosurgeons from performing Chiari decompression surgery. In this chapter, management strategies and surgical approaches are discussed that minimize the risks of complications and maximize favorable outcomes in Chiari malformation surgery.

Maximum Safety Limits of Laminectomy of the C1 Vertebra for Chiari Malformation Surgery: A Finite Element Analysis

Background

The treatment of Chiari malformations generally consists of posterior fossa decompression. C1 laminectomy is required in selected cases. However, cases of iatrogenic anterior arch fractures at C1 without high-energy trauma have been reported. Developing theoretical models of atlas C1 bones that have undergone a laminectomy can help researchers identify the regions where fractures may occur as a result of sudden loads.

Methods

In this study, we created a detailed three-dimensional solid finite element model of the human atlas bone (C1) using geometric data. The loadings of the laminectomy dimension were evaluated on the basis of three groups. Group I comprised atlas bones that had not undergone a laminectomy. For Group II, the lateral border of the laminectomy was determined as the projection of the lateral mass medial border on the lamina. For Group III, the bilateral sulcus arteriosus was determined as the border for the lateral border of the laminectomy. The analysis results, which are in good agreement with those of previous reports, showed high concentrations of localized stress in the anterior and posterior arches of the atlas bone.

Results

The analysis results showed that the stress increased in the laminectomy models. The maximum stress observed was consistent with the clinical observations of fracture sites in previous studies.

Conclusion

In the treatment of patients with Chiari malformations, C1 laminectomy is often required. The width of this laminectomy can lead to iatrogenic anterior arch fractures. This is the first study to evaluate C1 laminectomy width using finite element modeling.

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.

Imaging and health metrics in incidental cerebellar tonsillar ectopia: findings from the Adolescent Brain Cognitive Development Study (ABCD)

PURPOSE

Incidental cerebellar tonsillar ectopia (ICTE) that meets the radiographic criterion for Chiari malformation type I (CMI) is an increasingly common finding in the clinical setting, but its significance is unclear. The present study examined posterior cranial fossa (PCF) morphometrics and a broad range of health instruments of pediatric ICTE cases and matched controls extracted from the Adolescent Brain Cognitive Development (ABCD) dataset.

METHODS

One-hundred-six subjects with ICTE and 106 matched controls without ICTE were identified from 11,411 anatomical MRI of healthy screened pediatric subjects from the ABCD project. Subjects were matched by sex, age, body mass index, race, and ethnicity. Twenty-two brain morphometrics and 22 health instruments were compared between the two groups to identify unrecognized CMI symptoms and assess the general health impact of ICTE.

RESULTS

Twelve and 15 measures were significantly different between the ICTE and control groups for females and males, respectively. Notably, for females, the anterior CSF space was significantly smaller (p = 0.00005) for the ICTE group than controls. For males, the clivus bone length was significantly shorter (p = 0.0002) for the ICTE group compared to controls. No significant differences were found among the 22 health instruments between the two groups.

CONCLUSION

This study demonstrated that pediatric ICTE subjects have similar PCF morphometrics to adult CMI. ICTE alone did not appear to cause any unrecognized CMI symptoms and had no impact on the subjects' current mental, physical, or behavioral health. Still, given their cranial and brain morphology, these cases may be at risk for adult-onset symptomatic CMI.

External validation of current prediction systems of improvement after decompression surgery in Chiari malformation type I patients: can we do better?

OBJECTIVE

The Chiari Severity Index (CSI) and points-based algorithm of Thakar et al. are two prognostic tools that have been developed to predict the likelihood of improvement after suboccipital decompression in adult patients with Chiari malformation type I (CM-I). This study aimed to externally validate and critically evaluate these algorithms in the interest of guiding the development of improved prediction systems.

METHODS

A consecutive cohort of CM-I patients undergoing suboccipital decompression between September 2006 and September 2018 were included. The CSI and Thakar point score were computed for all patients, and associations with improvement were analyzed. The ability of both prediction systems to predict improvement as measured by different Chicago Chiari Outcome Scale (CCOS) cutoffs was assessed using receiver operating curve analysis. Post hoc correlations between the algorithms and different CCOS subcomponents were also assessed.

RESULTS

The surgical cohort was composed of 149 adult CM-I patients, of whom 39 (26%) had a syrinx. Most patients experienced improvement after surgery (80% CCOS ≥ 13; 96% CCOS ≥ 11). The proportion of patients improving decreased with increasing CSI, but the results were not statistically significant (p = 0.246). No statistically significant difference in the mean Thakar point score was identified between improved and nonimproved patients using both CCOS cutoffs (p = 0.246 for a cutoff of 13 and p = 0.480 for a cutoff of 11). The CSI had a poor ability in identifying improved patients at a CCOS cutoff of 13 (area under the curve [AUC] 0.582) and 11 (AUC 0.646). The Thakar point score similarly had poor discrimination at a cutoff of 13 (AUC 0.467) and 11 (AUC 0.646). Neither algorithm had significant correlation with any of the CCOS subcomponents except for CSI and nonpain symptom improvement (coefficient = -0.273, p = 0.001).

CONCLUSIONS

Previously published algorithms failed to provide prediction value with regard to clinically meaningful improvement following suboccipital decompression in adult CM-I patients. Future models and practical scoring systems are still required to improve the decision-making process.

Timing to surgery of Chiari malformation type 1 affects complication types: An analysis of 13,812 patients

Background:

Chiari malformations (CM) are congenital defects due to hypoplasia of the posterior fossa with cerebellar herniation into the foramen magnum and upper spinal canal. Despite the vast research done on this neurological and structural syndrome, clinical features and management options have not yet conclusively evolved. Quantification of proper treatment planning, can lead to potential perioperative benefits based on diagnoses and days to procedure. This study aims to identify if early operation produces better perioperative outcomes or if there are benefits to delaying CM surgery.

Aims and Objective:

Assess outcomes for Chiari type I.

Methods:

The KID database was queried for diagnoses of Chiari Malformation from 2003-2012 by icd9 codes (348.4, 741.0, 742.0, 742.2). Included patients: had complete time to procedure (TTP) data. Patients were stratified into 7 groups by TTP: Same-day as admission (SD), 1-day delay (1D), 2-day delay (2D), 3-day delay (3D), 4-7 days delay (4-7D), 8-14 days delay (8-14D), >14 days delay (>14D). Differences in pre-operative demographics (age/BMI) and perioperative complication rates between patient cohorts were assessed using Pearson's chi-squared tests and T-tests. Surgical details, perioperative complications, length of stay (LOS), total charges, and discharge disposition was compared. Binary logistic regressions determined independent predictors of varying complications (reference: same-day).

Results:

13,812 Chiari type I patients were isolated from KID (10.12 ± 6.3, 49.2F%, .063 ± 1.3CCI). CM-1 pts were older (10.12 yrs vs 3.62 yrs) and had a higher Charlson Comorbidity Score (0.62 vs 0.53; all P < 0.05). Procedure rates: 27.8% laminectomy, 28.3% decompression, and 2.2% spinal fusion. CM-1 experienced more complications (61.2% vs 37.9%) with the most common being related to the nervous system (2.8%), anemia (2.4%), acute respiratory distress disorder (2.1%), and dysphagia (1.2%). SD was associated with the low length of stay (5.3 days vs 9.5-25.2 days, P < 0.001), total hospital charges ($70,265.44 vs $90, 945.33-$269, 193.26, P < 0.001) when compared to other TTP groups. Relative to SD, all delay groups had significantly increased odds of developing postoperative complications (1D-OR: 1.29 [1.1- 1.6] → 8-14D-OR: 4.77[3.4-6.6]; all P < 0.05), more specifically, nervous system (1D-OR: 1.8 [1.2-2.5] → 8-14D-OR: 3.3 [1.8-6.2]; all P < 0.05).Sepsis complications were associated with a delay of at least 3D(2.5[1.4-4.6]) while respiratory complications (6.2 [3.1-12.3]) and anemia (2 [1.1-3.5]) were associated with a delay of at least 8-14D (all P < 0.05).

Emergency Department Visits Following Suboccipital Decompression for Adult Chiari Malformation Type I

BACKGROUND

Postoperative emergency department (ED) visits following suboccipital decompression in Chiari malformation type I (CM-1) patients are not well described. We sought to evaluate the magnitude, etiology, and significance of postoperative ED service utilization in adult CM-1 patients at a tertiary referral center.

METHODS

A prospectively maintained database of CM-1 patients seen at our institution between January 1, 2006 and December 31, 2019 was used. ED visits occurring within 30 days after surgery were tracked for postoperative patients, while comparing clinical, imaging, and operative characteristics between patients with and without an ED visit. Clinical improvement at last follow-up was also compared between both groups of patients in a univariable and multivariable analysis using the Chicago Chiari Outcome Scale (CCOS).

RESULTS

In 175 surgically treated patients, 44 (25%) visited an ED in the 1-month period after surgery. The most common reason for seeking care was isolated headache (41%), and concentration disturbance at presentation was the only factor significantly associated with a postoperative ED visit (P = 0.023). The occurrence of a postoperative ED visit was independently associated with a lower chance of clinical improvement at last follow-up (adjusted odds ratio of CCOS ≥13 = 0.35, P = 0.021; adjusted odds ratio of CCOS ≥14 = 0.38, P = 0.016).

CONCLUSIONS

Adult CM-1 patients undergoing surgery at a tertiary referral center have an elevated rate of postoperative ED visits, which are mostly due to pain-related complaints. Such visits are hard to predict but are associated with worse long-term clinical outcome. Interventions that decrease the magnitude of postoperative ED service utilization are warranted.

The impact of depression on surgical outcome in Chiari malformation type I: an assessment based on the Chicago Chiari Outcome Scale

OBJECTIVE

The effect of depression on outcomes in Chiari malformation type I (CM-1) is unclear. The authors sought to determine whether depression affects outcome in a surgical cohort of CM-1 patients by using a validated outcome assessment tool, the Chicago Chiari Outcome Scale (CCOS).

METHODS

The authors performed a retrospective analysis of a prospectively maintained database of 149 adult CM-1 patients undergoing suboccipital decompression with duraplasty and cranioplasty. Baseline presentation characteristics and composite as well as subcomponent CCOS scores at last follow-up were compared between depressed and nondepressed patients. Outcome comparisons included both a univariable analysis and a logistic regression model adjusting for several covariates.

RESULTS

The prevalence of depression in the study cohort was 28% (41/149). Baseline demographic and imaging characteristics were similar between the 2 patient groups. Dizziness (p = 0.019) and imbalance (p = 0.015) were significantly more common among depressed patients, but clinical symptoms and severity were otherwise comparable. On univariable analysis, depressed patients were significantly less likely to experience improvement in pain symptoms (OR 0.14, 95% CI 0.03-0.61, p = 0.003) and functionality (OR 0.17, 95% CI 0.03-0.99, p = 0.049). No significant difference was identified in complications, nonpain symptom improvement, or overall composite CCOS improvement. Similar results were obtained on multivariable analysis controlling for several covariates.

CONCLUSIONS

Depression is independently associated with poor surgical outcome in adult CM-1 patients, namely when evaluating improvement in pain symptoms and functionality. Optimizing the management of depression preoperatively and ensuring follow-up for psychiatric comorbidity in the postoperative period may possibly lead to improved outcomes.

Family History in Chiari Malformation Type I: Presentation and Outcome

BACKGROUND

Some patients with Chiari malformation type I (CM-1) present with a positive family history of CM-1, the significance of which remains unknown. We aimed to study whether family history affects the clinical presentation characteristics and surgical outcome of adult patients with CM-1.

METHODS

A database of adult patients with CM-1 presenting between January 1, 2006 and December 31, 2018 was used. Presenting characteristics were compared between patients with and without a family history (first, second, or third degree) of CM-1. Among surgically treated patients, perioperative and long-term outcomes, with favorable outcome defined as a Chiari Outcome Scale score ≥14, were compared between patients with and without CM-1 family history. All patients completed at least 6 months of postoperative follow-up.

RESULTS

The database consisted of 233 adult patients with CM-1, 14 of whom (6%) had a positive family history. Presenting characteristics were comparable between patients with and without a positive family history. A total of 150 patients underwent suboccipital decompression, 12 of whom (8%) had a positive family history. After a mean follow-up of 1.9 years, patients with a family history of CM-1 were significantly less likely to achieve a favorable outcome (odds ratio, 0.22; 95% confidence interval, 0.06-0.78; P = 0.019) while controlling for several covariates. Post hoc analysis showed that the difference was most significant when looking at pain symptoms.

CONCLUSIONS

Presentation characteristics are comparable between patients with and without a family history of CM-1. Patients with a positive family history may be less likely to respond favorably to suboccipital decompression.

The SHORE Score: A Novel Predictive Tool for Improvement After Decompression Surgery in Adult Chiari Malformation Type I

BACKGROUND

A practical scoring system predicting significant improvement after surgical decompression in adult Chiari malformation type I (CM-1) based on validated outcome measures is lacking. We aimed to develop a simple score and improvement calculator to facilitate the decision making process in symptomatic CM-1 patients.

METHODS

We evaluated adult CM-1 patients who presented to our institution between September 2006 and September 2018 and underwent surgical decompression. Previously treated patients were excluded. Univariable analysis and multivariable logistic regression were conducted to derive an optimal model predictive of improvement on last follow-up as measured by the Chicago Chiari Outcome Scale. A score was derived using the beta coefficients of the model, and predictive performance was assessed using receiver operating curves with bootstrap validation. Finally, a web-based improvement calculator was deployed.

RESULTS

The surgical cohort consisted of 149 adult CM-1 patients, of which 100 (67%) experienced significant clinical improvement (Chicago Chiari Outcome Scale ≥14) after a mean follow-up of 1.9 years. The final model predictive of significant clinical improvement consisted of headache with Valsalva (odds ratio [OR] = 2.39; P = 0.030), nonwhite race (OR = 2.57; P = 0.041), absence of visual symptoms (OR = 2.59; P = 0.015), syrinx absence (OR = 1.59; P = 0.315), and increased odontoid retroflexion (OR = 2.82; P = 0.009). The score was termed SHORE, which summarizes the model's predictive factors, each assigned 1 point. The model had an area under the curve of 0.754 with an optimism-correct value of 0.721. A calculator was deployed under: https://jhuspine2.shinyapps.io/SHORE_score/.

CONCLUSIONS

The score and calculator can serve as supplements to clinical decision making by providing realistic and personalized expectations of postoperative outcome.

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 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.

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.

Cost-Effectiveness of Postoperative Ketamine in Chiari Decompression

INTRODUCTION

In Chiari I patients, postoperative pain and discomfort frequently slow the transition back to the home setting.

OBJECTIVE

We sought to determine the effect of standardized ketamine infusion protocols on hospital length of stay (LOS).

METHODS

This retrospective cohort study reviewed 100 consecutive adult patients undergoing Chiari I decompression. Fifty-nine patients were placed on a 2-3 mg/hr ketamine drip until postoperative day 1. This group was compared with a group who received 2-3 mg/hr of ketamine until postoperative day 2 (19 patients) and patients who did not receive ketamine at all (22 patients). Clinical characteristics, opioid use, LOS, and relative hospitalization costs were assessed. All narcotic amounts were converted into milligram equivalents of morphine.

RESULTS

LOS of the short-ketamine group was 46.5 hours when compared with the long-ketamine group (66.8 hours) and no-ketamine group (56.9 hours). There was a statistically significant difference when comparing the short-ketamine group with the long-ketamine group and no-ketamine group together (P < 0.001), as well as when compared individually (P = 0.001 and 0.004). The mean cost of hospitalization was 20% less when a short-ketamine protocol was used (P < 0.001). Mean morphine milligram equivalents used postoperatively were 148 mg in the short-ketamine group, 196 mg in the long-ketamine group, and 187 mg in the no-ketamine group (P = 0.65). No adverse events from ketamine were noted.

CONCLUSIONS

Ketamine at subanesthetic levels may be an effective tool to facilitate early return home postoperatively and may significantly reduce medical costs.

Chiari Malformation Type 1: A Systematic Review of Natural History and Conservative Management

BACKGROUND

Chiari malformation type 1 (CM-1) is a variation of hindbrain development that can sometimes occur in asymptomatic individuals. Conventional treatment is surgical decompression, but little is known about the natural history of patients who do not undergo surgical management. This information is critical to determine how these patients should be managed. We conducted a systematic literature review to determine the natural history of CM-1, particularly in patients who did not undergo surgery and in asymptomatic individuals, to help patients and physicians determine when surgery is likely to be beneficial.

METHODS

The literature search was performed following Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines using the electronic databases PubMed, Scopus, Cochrane Library, and Web of Science. Inclusion and exclusion criteria were predefined.

RESULTS

In symptomatic patients who did not undergo surgery, headaches and nausea often improved, whereas ataxia and sensory disturbance tended not to improve spontaneously. Of patients, 27%-47% had an improvement in symptoms after 15 months, and 37%-40% with cough headache and 89% with nausea who were managed nonoperatively improved at follow-up. Most asymptomatic individuals with CM-1 remained asymptomatic (93.3%) even in the presence of syringomyelia.

CONCLUSIONS

The natural history of mild symptomatic and asymptomatic CM-1 in adults is relatively benign and nonprogressive; the decision to perform surgical decompression should be based on severity and duration of a patient's symptoms at presentation. It is reasonable to observe a patient with mild or asymptomatic symptoms even in the presence of significant tonsillar descent or syringomyelia.

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.

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.

A Patient Registry to Improve Patient Safety: Recording General Neurosurgery Complications

Background

To improve the transparency of the local health care system, treatment cost was recently referenced to disease related groups. Treatment quality must be legally documented in a patient registry, in particular for the highly specialized treatments provided by neurosurgery departments.

Methods

In 2013 we have installed a patient registry focused on cranial neurosurgery. Surgeries are characterized by indication, treatment, location and other specific neurosurgical parameters. Preoperative state and postoperative outcome are recorded prospectively using neurological and sociological scales. Complications are graded by their severity in a therapy-oriented complication score system (Clavien-Dindo-Grading system, CDG). Results are presented at the monthly clinical staff meeting.

Results

Data acquisition compatible with the clinic workflow permitted to include all eligible patients into the registry. Until December 2015, we have registered 2880 patients that were treated in 3959 surgeries and 8528 consultations. Since the registry is fully operational (August 2014), we have registered 325 complications on 1341 patient discharge forms (24%). In 64% of these complications, no or only pharmacological treatment was required. At discharge, there was a clear correlation of the severity of the complication and the Karnofsky Performance Status (KPS, ρ = -0.3, slope -6 KPS percentage points per increment of CDG) and the length of stay (ρ = 0.4, slope 1.5 days per increment of CDG).

Conclusions

While the therapy-oriented complication scores correlate reasonably well with outcome and length of stay, they do not account for new deficits that cannot be treated. Outcome grading and complication severity grading thus serve a complimentary purpose. Overall, the registry serves to streamline and to complete information flow in the clinic, to identify complication rates and trends early for the internal quality monitoring and communication with patients. Conversely, the registry influences clinical practice in that it demands rigorous documentation and standard operating procedures.

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.

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

OBJECTIVE Chiari malformation Type I (CM-I) is a common and often debilitating pediatric neurological disease. However, efforts to guide preoperative counseling and improve outcomes research are impeded by reliance on small, single-center studies. Consequently, the objective of this study was to investigate CM-I surgical outcomes using population-level administrative billing data. METHODS The authors used Healthcare Cost and Utilization Project State Inpatient Databases (SID) to study pediatric patients undergoing surgical decompression for CM-I from 2004 to 2010 in California, Florida, and New York. They assessed the prevalence and influence of preoperative complex chronic conditions (CCC) among included patients. Outcomes included medical and surgical complications within 90 days of treatment. Multivariate logistic regression was used to identify risk factors for surgical complications. RESULTS A total of 936 pediatric CM-I surgeries were identified for the study period. Overall, 29.2% of patients were diagnosed with syringomyelia and 13.7% were diagnosed with scoliosis. Aside from syringomyelia and scoliosis, 30.3% of patients had at least 1 CCC, most commonly neuromuscular (15.2%) or congenital or genetic (8.4%) disease. Medical complications were uncommon, occurring in 2.6% of patients. By comparison, surgical complications were diagnosed in 12.7% of patients and typically included shunt-related complications (4.0%), meningitis (3.7%), and other neurosurgery-specific complications (7.4%). Major complications (e.g., stroke or myocardial infarction) occurred in 1.4% of patients. Among children with CCCs, only comorbid hydrocephalus was associated with a significantly increased risk of surgical complications (OR 4.5, 95% CI 2.5-8.1). CONCLUSIONS Approximately 1 in 8 pediatric CM-I patients experienced a surgical complication, whereas medical complications were rare. Although CCCs were common in pediatric CM-I patients, only hydrocephalus was independently associated with increased risk of surgical events. These results may inform patient counseling and guide future research efforts.

Validation of an International Classification of Diseases, Ninth Revision Code Algorithm for Identifying Chiari Malformation Type 1 Surgery in Adults

BACKGROUND

The use of administrative billing data may enable large-scale assessments of treatment outcomes for Chiari Malformation type I (CM-1). However, to utilize such data sets, validated International Classification of Diseases, Ninth Revision (ICD-9-CM) code algorithms for identifying CM-1 surgery are needed.

OBJECTIVE

To validate 2 ICD-9-CM code algorithms identifying patients undergoing CM-1 decompression surgery.

METHODS

We retrospectively analyzed the validity of 2 ICD-9-CM code algorithms for identifying adult CM-1 decompression surgery performed at 2 academic medical centers between 2001 and 2013. Algorithm 1 included any discharge diagnosis code of 348.4 (CM-1), as well as a procedure code of 01.24 (cranial decompression) or 03.09 (spinal decompression, or laminectomy). Algorithm 2 restricted this group to patients with a primary diagnosis of 348.4. The positive predictive value (PPV) and sensitivity of each algorithm were calculated.

RESULTS

Among 340 first-time admissions identified by Algorithm 1, the overall PPV for CM-1 decompression was 65%. Among the 214 admissions identified by Algorithm 2, the overall PPV was 99.5%. The PPV for Algorithm 1 was lower in the Vanderbilt (59%) cohort, males (40%), and patients treated between 2009 and 2013 (57%), whereas the PPV of Algorithm 2 remained high (≥99%) across subgroups. The sensitivity of Algorithms 1 (86%) and 2 (83%) were above 75% in all subgroups.

CONCLUSION

ICD-9-CM code Algorithm 2 has excellent PPV and good sensitivity to identify adult CM-1 decompression surgery. These results lay the foundation for studying CM-1 treatment outcomes by using large administrative databases.