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Analiz Rodriguez, Elizabeth N. Kuhn, Aravind Somasundaram and Daniel E. Couture

OBJECT

Syringohydromyelia is frequently identified on spinal imaging. The literature provides little guidance to decision making regarding the need for follow-up or treatment. The purpose of this study was to review the authors' experience in managing pediatric syringohydromyelia of unknown cause.

METHODS

A single-institution retrospective review of all cases involving pediatric patients who underwent spinal MRI from 2002 to 2012 was conducted. Patients with idiopathic syringohydromyelia (IS) were identified and categorized into 2 subgroups: uncomplicated idiopathic syrinx and IS associated with scoliosis. Clinical and radiological course were analyzed.

RESULTS

Ninety-eight patients (50 female, 48 male) met the inclusion criteria. Median age at diagnosis of syrinx was 11.9 years. Median maximum syrinx size was 2 mm (range 0.5–17 mm) and spanned 5 vertebral levels (range 1–20 vertebral levels). Thirty-seven patients had scoliosis. The most common presenting complaint was back pain (26%). Clinical follow-up was available for 78 patients (80%), with a median follow-up of 20.5 months (range 1–143 months). A neurological deficit existed at presentation in 36% of the patients; this was either stable or improved at last follow-up in 64% of cases. Radiological follow-up was available for 38 patients (39%), with a median duration of 13 months (range 2–83 months). There was no change in syrinx size in 76% of patients, while 16% had a decrease and 8% had an increase in syrinx size. Thirty-six patients had both clinical and radiological follow-up. There was concordance between clinical and radiological course in 14 patients (39%), with 11 patients (31%) showing no change and 3 patients (8%) showing clinical and radiological improvement.

No patients had concurrent deterioration in clinical and radiological course. One patient with scoliosis and muscular dystrophy underwent direct surgical treatment of the syrinx and subsequently had a deteriorated clinical course and decreased syrinx size.

CONCLUSIONS

There remains a paucity of data regarding the management of pediatric IS. IS in association with scoliosis can complicate neurosurgical decision making. There was no concordance between radiological syrinx size increase and clinical deterioration in this cohort, indicating that surgical decision making should reflect clinical course as opposed to radiological course.

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Elizabeth N. Kuhn, Betsy Hopson, Michael J. Conklin and Jeffrey P. Blount

OBJECTIVE

Patients with myelomeningocele are often affected by scoliosis and tethered cord syndrome, and frequently require spine surgery. Intradural spine surgeries may carry an inherently higher risk of inducing shunt malfunction due to entry into the subarachnoid space. In this study, the authors sought to compare rates of shunt malfunction after intradural and extradural spine surgeries among pediatric patients with myelomeningocele.

METHODS

The authors reviewed records of the National Spina Bifida Program Registry for Children’s Hospital of Alabama. The Exago reporting function was used to identify patients who had received at least one of the following procedures: shunt revision, tethered cord release (TCR), or spinal fusion for deformity. The registry records were reviewed for all identified patients to determine if a shunt revision was performed within the 1st year after TCR or spinal fusion.

RESULTS

Final analyses included 117 patients, of whom 39 underwent spinal fusion and 78 underwent TCR. Among patients who underwent spinal fusion, shunt revision was performed within 30 days in 2 patients (5.1%), within 60 days in 2 (5.1%), within 90 days in 4 (10.3%), and within 1 year in 5 (12.8%). Among patients who underwent TCR, shunt revision was performed within 30 days in 7 patients (9.0%), within 60 days in 10 (12.8%), within 90 days in 11 (14.1%), and within 1 year in 17 (21.8%). Using the log-rank test, there was no significant difference in Kaplan-Meier curves between intradural and extradural groups (p = 0.59).

CONCLUSIONS

In a review of single-institution registry data, the authors found no statistically significant difference in the risk of shunt malfunction after intradural and extradural spine surgeries.

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Matthew C. Davis, Elizabeth N. Kuhn, Bonita S. Agee, Robert A. Oster and James M. Markert

OBJECTIVE

Many neurosurgical training programs have moved from a 24-hour resident call system to a night float system, but the impact on outcomes is unclear. Here, the authors compare length of stay (LOS) for neurosurgical patients admitted before and after initiation of a night float system at a tertiary care training hospital.

METHODS

The neurosurgical residency at the University of Alabama at Birmingham transitioned from 24-hour call to a night float resident coverage system in July 2013. In this cohort study, all patients admitted to the neurosurgical service for 1 year before and 1 year after this transition were compared with respect to hospital and ICU LOSs, adjusted for potential confounders.

RESULTS

A total of 4619 patients were included. In the initial bivariate analysis, night float was associated with increased ICU LOS (p = 0.032) and no change in overall LOS (p = 0.65). However, coincident with the transition to a night float system was an increased frequency of resident service transitions, which were highly associated with hospital LOS (p < 0.01) and ICU LOS (p < 0.01). After adjusting for resident service transitions, initiation of the night float system was associated with decreased hospital LOS (p = 0.047) and no change in ICU LOS (p = 0.35).

CONCLUSIONS

This study suggests that a dedicated night float resident may improve night-to-night continuity of care and decrease hospital LOS, but caution must be exercised when initiation of night float results in increased resident service transitions.

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Elizabeth N. Kuhn, Matthew C. Davis, Bonita S. Agee, Robert A. Oster and James M. Markert

OBJECT

Handoffs and services changes are potentially modifiable sources of medical error and delays in transition of care. This cohort study assessed the relationship between resident service handoffs and length of stay for neurosurgical patients.

METHODS

All patients admitted to the University of Alabama at Birmingham neurosurgical service between July 1, 2012, and July 1, 2014, were retrospectively identified. A service handoff was defined as any point when a resident handed off coverage of a service for longer than 1 weekend. A conditional probability distribution was constructed to adjust length of stay for the increasing probability of a random handoff. The Student t-test and ANCOVA were used to assess relationships between resident service handoffs and length of hospital stay, adjusted for potential confounders.

RESULTS

A total of 3038 patients met eligibility criteria and were included in the statistical analyses. Adjusted length of hospital stay (5.32 vs 3.53 adjusted days) and length of ICU stay (4.38 vs 2.96 adjusted days) were both longer for patients who experienced a service handoff, with no difference in mortality. In the ANCOVA model, resident service handoff remained predictive of both length of hospital stay (p < 0.001) and length of ICU stay (p < 0.001).

CONCLUSIONS

Occurrence of a resident service handoff is an independent predictor of length of hospital and ICU stay in neurosurgical patients. This finding is novel in the neurosurgical literature. Future research might identify mechanisms for improving continuity of care and mitigating the effect of resident handoffs on patient outcomes.

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Ann Liu, Elizabeth N. Kuhn, John T. Lucas Jr., Adrian W. Laxton, Stephen B. Tatter and Michael D. Chan

OBJECT

Neurofibromatosis Type 2 (NF2) is a rare autosomal dominant disorder predisposing patients to meningiomatosis. The role of stereotactic radiosurgery (SRS) is poorly defined in NF2, and although the procedure has excellent control rates in the non-NF2 population, its utility has been questioned because radiation has been hypothesized to predispose patients to malignant transformation of benign tumors. To the authors' knowledge, this is the first study to examine the use of SRS specifically for meningiomas in patients with NF2.

METHODS

The authors searched a tumor registry for all patients with NF2 who had undergone Gamma Knife radiosurgery (GKRS) for meningioma in the period from January 1, 1999, to September 19, 2013, at a single tertiary care cancer center. Medical records were retrospectively reviewed for patient and tumor characteristics and outcomes.

Results

Among the 12 patients who met the search criteria, 125 meningiomas were identified, 87 (70%) of which were symptomatic or progressive and thus treated with GKRS. The median age at the first GKRS was 31 years (interquartile range [IQR] 27–37 years). Five patients (42%) had multiple treatments with a median of 27 months (IQR 14–50 months) until the subsequent GKRS. The median follow-up in surviving patients was 43 months (IQR 34–110 months). The 5-year local tumor control and distant treatment failure rates were 92% and 77%, respectively. Toxicities occurred in 25% of the GKRS treatments, although the majority were Grade 1 or 2. At the last follow-up, 4 patients (33%) had died a neurological death at a median age of 39 years (IQR 37–46 years), and their cases accounted for 45% of all tumors, 55% of all treated tumors, and 58% of all GKRSs. Univariate analysis revealed several predictive variables for distant failure, including male sex (HR 0.28, 95% CI 0.086–0.92, p = 0.036), age at distant failure (HR 0.92, 95% CI 0.90–0.95, p < 0.0001), and prior number of GKRS treatments (HR 1.2, 95% CI 1.1–1.4, p = 0.0049). Local failure, maximum size of the treated tumor, delivered tumor margin dose, and WHO grade were not significant. On multivariate analysis, age at distant failure (HR 0.91, 95% CI 0.88–0.95, p < 0.0001) and prior number of GKRSs (HR 1.3, 95% CI 1.1–1.5, p = 0.004) remained significant. No malignant transformation events among treated tumors were observed.

CONCLUSIONS

Radiosurgery represents a feasible modality with minimal toxicity for NF2-associated meningiomas. Increasing patient age was associated with a decreased rate of distant failure, whereas an increasing number of prior GKRS treatments predicted distant failure. Further studies are necessary to determine the long-term patterns of treatment failure in these patients.

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Elizabeth N. Kuhn, Glen B. Taksler, Orrin Dayton, Amritraj G. Loganathan, Tamara Z. Vern-Gross, J. Daniel Bourland, Adrian W. Laxton, Michael D. Chan and Stephen B. Tatter

Object

The purpose of this study was to evaluate patterns of failure after stereotactic radiosurgery (SRS) for meningiomas and factors that may influence these outcomes.

Methods

Based on a retrospective chart review, 279 patients were treated with SRS for meningiomas between January 1999 and March 2011 at Wake Forest Baptist Health. Disease progression was determined using serial imaging, with a minimum follow-up of 6 months (median 34.2 months).

Results

The median margin dose was 12.0 Gy (range 8.8–20 Gy). Local control rates for WHO Grade I tumors were 96.6%, 84.4%, and 75.7% at 1, 3, and 5 years, respectively. WHO Grade II and III tumors had local control rates of 72.3%, 57.7%, and 52.9% at 1, 3, and 5 years, respectively. Tumors without pathological grading had local control rates of 98.7%, 97.6%, and 94.2% at 1, 3, and 5 years, respectively. Of the local recurrences, 63.1% were classified as marginal (within 2 cm of treatment field). The 1-, 3-, and 5-year rates of distant failure were 6.5%, 10.3%, and 16.6%, respectively, for Grade I tumors and 11.4%, 17.2%, and 22.4%, respectively, for Grade II/III tumors. Tumors without pathological grading had distant failure rates of 0.7%, 3.2%, and 6.5% at 1, 3, and 5 years, respectively. Wilcoxon analysis revealed that multifocal disease (p < 0.001) and high-grade histology (WHO Grade II or III; p < 0.001) were significant predictors of local recurrence. Additionally, male sex was a significant predictor of distant recurrence (p = 0.04). Multivariate analysis also showed that doses greater than or equal to 12 Gy were associated with improved local control (p = 0.015).

Conclusions

In this patient series, 12 Gy was the minimum sufficient margin dose for the treatment of meningiomas. Male sex is a risk factor for distant failure, whereas high-grade histology and multifocal disease are risk factors for local failure.

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Ross L. Dawkins, Joseph H. Miller, Omar I. Ramadan, Michael C. Lysek, Elizabeth N. Kuhn, Brandon G. Rocque, Michael J. Conklin, R. Shane Tubbs, Beverly C. Walters, Bonita S. Agee and Curtis J. Rozzelle

OBJECTIVE

There are many classification systems for injuries of the thoracolumbar spine. The recent Thoracolumbar Injury Classification and Severity Score (TLICS) has been shown to be a reliable tool for adult patients. The aim of this study was to assess the reliability of the TLICS system in pediatric patients. The validity of the TLICS system is assessed in a companion paper.

METHODS

The medical records of pediatric patients with acute, traumatic thoracolumbar fractures at a single Level 1 trauma center were retrospectively reviewed. A TLICS was calculated for each patient using CT and MRI, along with the neurological examination recorded in the patient’s medical record. TLICSs were compared with the type of treatment received. Five raters scored all patients separately to assess interrater reliability.

RESULTS

TLICS calculations were completed for 81 patients. The mean patient age was 10.9 years. Girls represented 51.8% of the study population, and 80% of the study patients were white. The most common mechanisms of injury were motor vehicle accidents (60.5%), falls (17.3%), and all-terrain vehicle accidents (8.6%). The mean TLICS was 3.7 ± 2.8. Surgery was the treatment of choice for 33.3% of patients. The agreement between the TLICS-suggested treatment and the actual treatment received was statistically significant (p < 0.0001). The interrater reliability of the TLICS system ranged from moderate to very good, with a Fleiss’ generalized kappa (κ) value of 0.69 for the TLICS treatment suggestion among all patients; however, interrater reliability decreased when MRI was used to contribute to the TLICS. The κ value decreased from 0.73 to 0.57 for patients with CT only vs patients with CT/MRI or MRI only, respectively (p < 0.0001). Furthermore, the agreement between suggested treatment and actual treatment was worse when MRI was used as part of injury assessment.

CONCLUSIONS

The TLICS system demonstrates good interrater reliability among physicians assessing thoracolumbar fracture treatment in pediatric patients. Physicians should be cautious when using MRI to aid in the surgical decision-making process.

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Joseph H. Miller, Clarence Gill, Elizabeth N. Kuhn, Brandon G. Rocque, Joshua Y. Menendez, Jilian A. O'Neill, Bonita S. Agee, Steven T. Brown, Marshall Crowther, R. Drew Davis, Drew Ferguson and James M. Johnston

OBJECT

Pediatric sports-related concussions are a growing public health concern. The factors that determine injury severity and time to recovery following these concussions are poorly understood. Previous studies suggest that initial symptom severity and diagnosis of attention deficit hyperactivity disorder (ADHD) are predictors of prolonged recovery (> 28 days) after pediatric sports-related concussions. Further analysis of baseline patient characteristics may allow for a more accurate prediction of which patients are at risk for delayed recovery after a sports-related concussion.

METHODS

The authors performed a single-center retrospective case-control study involving patients cared for at the multidisciplinary Concussion Clinic at Children's of Alabama between August 2011 and January 2013. Patient demographic data, medical history, sport concussion assessment tool 2 (SCAT2) and symptom severity scores, injury characteristics, and patient balance assessments were analyzed for each outcome group. The control group consisted of patients whose symptoms resolved within 28 days. The case group included patients whose symptoms persisted for more than 28 days. The presence or absence of the SCAT2 assessment had a modifying effect on the risk for delayed recovery; therefore, stratum-specific analyses were conducted for patients with recorded SCAT2 scores and for patients without SCAT2 scores. Unadjusted ORs and adjusted ORs (aORs) for an association of delayed recovery outcome with specific risk factors were calculated with logistic regression analysis.

RESULTS

A total of 294 patients met the inclusion criteria of the study. The case and control groups did not statistically significantly differ in age (p = 0.7). For the patients who had received SCAT2 assessments, a previous history of concussion (aOR 3.67, 95% CI 1.51–8.95), presenting SCAT2 score < 80 (aOR 5.58, 95% CI 2.61–11.93), and female sex (aOR 3.48, 95% CI 1.43–8.49) were all associated with a higher risk for postconcussive symptoms lasting more than 28 days. For patients without SCAT2 scores, female sex and reporting a history of ADHD significantly increased the odds of prolonged recovery (aOR 4.41, 95% CI 1.93–10.07 and aOR 3.87, 95% CI 1.13–13.24, respectively). Concussions resulting from playing a nonhelmet sport were also associated with a higher risk for prolonged symptoms in patients with and without SCAT2 scores (OR 2.59, 95% CI 1.28–5.26 and OR 2.17, 95% CI 0.99–7.73, respectively). Amnesia, balance abnormalities, and a history of migraines were not associated with symptoms lasting longer than 28 days.

CONCLUSIONS

This case-control study suggests candidate risk factors for predicting prolonged recovery following sports-related concussion. Large prospective cohort studies of youth athletes examined and treated with standardized protocols will be needed to definitively establish these associations and confirm which children are at highest risk for delayed recovery.

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Tofey J. Leon, Elizabeth N. Kuhn, Anastasia A. Arynchyna, Burkely P. Smith, R. Shane Tubbs, James M. Johnston, Jeffrey P. Blount, Curtis J. Rozzelle, W. Jerry Oakes and Brandon G. Rocque

OBJECTIVE

There are sparse published data on the natural history of “benign” Chiari I malformation (CM-I)—i.e., Chiari with minimal or no symptoms at presentation and no imaging evidence of syrinx, hydrocephalus, or spinal cord signal abnormality. The purpose of this study was to review a large cohort of children with benign CM-I and to determine whether these children become symptomatic and require surgical treatment.

METHODS

Patients were identified from institutional outpatient records using International Classification of Diseases, 9th Revision, diagnosis codes for CM-I from 1996 to 2016. After review of the medical records, patients were excluded if they 1) did not have a diagnosis of CM-I, 2) were not evaluated by a neurosurgeon, 3) had previously undergone posterior fossa decompression, or 4) had imaging evidence of syringomyelia at their first appointment. To include only patients with benign Chiari (without syrinx or classic Chiari symptoms that could prompt immediate intervention), any patient who underwent decompression within 9 months of initial evaluation was excluded. After a detailed chart review, patients were excluded if they had classical Chiari malformation symptoms at presentation. The authors then determined what changes in the clinical picture prompted surgical treatment. Patients were excluded from the multivariate logistic regression analysis if they had missing data such as race and insurance; however, these patients were included in the overall survival analysis.

RESULTS

A total of 427 patients were included for analysis with a median follow-up duration of 25.5 months (range 0.17–179.1 months) after initial evaluation. Fifteen patients had surgery at a median time of 21.0 months (range 11.3–139.3 months) after initial evaluation. The most common indications for surgery were tussive headache in 5 (33.3%), syringomyelia in 5 (33.3%), and nontussive headache in 5 (33.3%). Using the Kaplan-Meier method, rate of freedom from posterior fossa decompression was 95.8%, 94.1%, and 93.1% at 3, 5, and 10 years, respectively.

CONCLUSIONS

Among a large cohort of patients with benign CM-I, progression of imaging abnormalities or symptoms that warrant surgical treatment is infrequent. Therefore, these patients should be managed conservatively. However, clinical follow-up of such individuals is justified, as there is a low, but nonzero, rate of new symptom or syringomyelia development. Future analyses will determine whether imaging or clinical features present at initial evaluation are associated with progression and future need for treatment.