Faculty Bibliography

BACKGROUND AND IMPORTANCE:Although rare, severe congenital cervical spine deformity can present with limited treatment options and potentially catastrophic outcomes. The use of halter traction for cervical deformity correction in children has been well described, but it has not been previously reported in the management of neonates. CLINICAL PRESENTATION:A baby girl born at full-term gestation presented with generalized hypotonia, bilateral club feet, and significant right upper extremity weakness. Imaging demonstrated a severe congenital swan-neck deformity with spinal cord compression. Halter traction was initiated in the neonatal intensive care unit with subsequent neurological and radiographic improvement. After 7 days, traction was discontinued and she was placed in a custom-fitted cervico-thoracic orthosis. At 2 years of follow-up, she remains neurologically stable with maintained cervical alignment. CONCLUSION:Halter traction followed by external bracing is technically possible in the neonatal period. For children with severe cervical congenital deformity, this technique can reduce spinal cord compression, provide significant deformity correction, and delay the need for definitive operative spinal stabilization.

PURPOSE/OBJECTIVE:In children with early onset scoliosis (EOS) who have tethered spinal cord (TSC), spinal cord detethering is commonly performed prior to spinal deformity correction (SDC). The purpose of this study was to investigate whether age or curve magnitude at the time of detethering is associated with curve progression at a follow-up of at least 2 years. It was hypothesized that patients who undergo detethering at a younger age, or those with a smaller curve magnitude, would experience a reduced rate of curve progression when compared with those who are older or with larger curves. METHODS:Patients with EOS who underwent detethering at least 2 years prior to SDC were identified in a multicenter international registry. Radiographs were assessed just prior to the detethering procedure (pre-detether) and at the most recent visit prior to SDC (most recent post-detether). The rate of curve progression > 10° was examined. Owing to unequal follow-up in individual patients, Cox regression was used to investigate associations between primary variables (age and magnitude of major coronal curve) and rate of curve progression. RESULTS:37 patients met inclusion criteria and 18 (mean age: 3.7 ± 2.9 years, 66.7% female, mean follow-up: 3.4 ± 1.3 years) had radiographic data available for analysis. Pre-detether and most recent post-detether major coronal curves were 44.8° ± 18.5° and 47.6° ± 23.9°, respectively. 5 (27.8%) patients had curve progression > 10° at a follow-up of 3.2 ± 1.2 years. Patients with progression > 10° were older at the time of detethering when compared with those without (5.6 ± 2.8 vs. 3 ± 2.7 years, p = 0.084). Regression analysis demonstrated that as age at detethering increased by 1 year, the rate of curve progression > 10° increased by 28.6% [95% confidence interval (CI) 0.899; 1.839, p = 0.169]. There was no evidence of an association between pre-detethering curve magnitude and rate of curve progression > 10° [HR: 1.027, 95% CI 0.977; 1.079, p = 0.297]. CONCLUSION/CONCLUSIONS:In a small multicenter cohort of EOS patients with TSC, younger age, but not curve size, at the time of detethering was associated with a lower rate of scoliosis progression. Although these results indicate a potential role for early spinal cord detethering in the EOS population, they require further prospective investigation with a larger number of patients. LEVEL OF EVIDENCE/METHODS:Level II.

Described in the seminal paper by Hans Chiari in 1891, the Chiari I malformation (CMI) is a radiographic diagnosis commonly encountered by neurosurgeons and is often treated surgically with generally positive clinic outcomes. Studies have documented that 1% to 4% of patients undergoing MRI of the brain or cervical spine will be diagnosed with CMI, characterized by greater than 5 mm tonsillar herniation below the foramen magnum. More recently CMI has been described as a spectrum of disease, which includes Chiari 0, Chiari 1.5, and the complex Chiari. Primarily through multicenter clinical outcomes research, our understanding of the pathology continues to evolve.

PURPOSE/OBJECTIVE:In patients with early onset scoliosis (EOS) and intraspinal anomalies, surgery may be necessary for both the tethered spinal cord (TSC) and spinal deformity. The purpose of this study was to determine if there is a difference in complications when TSC release and surgery for spinal deformity correction (SDC) are performed separately compared simultaneously. METHODS:EOS patients with TSC who underwent detethering and SDC surgeries were identified through a multicenter registry. Patients were stratified into two groups. The simultaneous cohort consisted of patients receiving both detethering and SDC surgeries in a single anesthetic event on the same day, and the staged cohort consisted of patients undergoing detethering and SDC on two separate occasions. Postoperative complications up to 180 days for either surgery were assessed. RESULTS:Twenty five (65.8%) patients were staged and 13 (34.2%) underwent a simultaneous approach. Percent curve correction following SDC surgery did not significantly differ between the groups (p = 0.36). Within 90 days postoperatively, 16 complications in 11 patients (44.0%) occurred in the staged group, whereas no complications occurred in the simultaneous cohort (p = 0.006). From 90-days to 180-days postoperatively, 4 additional complications in 3 patients (12.0%) occurred in the staged group, with no complications reported in the same timeframe for the simultaneous cohort. CONCLUSION/CONCLUSIONS:To our knowledge, this is the largest multicenter comparative study to date, and it suggests that a simultaneous approach can be performed safely for EOS patients undergoing detethering and SDC surgeries, with a potentially lower risk profile than the traditional staged approach to these pathologies. LEVEL OF EVIDENCE/METHODS:Level III.

Pediatric spinal trauma is a broad topic with nuances specific to each anatomic region of the spinal column. The purpose of this report is to provide a brief review highlighting the most important and common clinical issues regarding the diagnosis and management of pediatric spine trauma. Detailed descriptions of imaging findings along with specific operative and nonoperative management of each fracture and dislocation type are beyond the scope of this review.

Adamantinomatous craniopharyngioma (ACP) is a biologically benign but clinically aggressive lesion that has a significant impact on quality of life. The incidence of the disease has a bimodal distribution, with peaks occurring in children and older adults. Our group previously published the results of a transcriptome analysis of pediatric ACPs that identified several genes that were consistently overexpressed relative to other pediatric brain tumors and normal tissue. We now present the results of a transcriptome analysis comparing pediatric to adult ACP to identify biological differences between these groups that may provide novel therapeutic insights or support the assertion that potential therapies identified through the study of pediatric ACP may also have a role in adult ACP. Using our compiled transcriptome dataset of 27 pediatric and 9 adult ACPs, obtained through the Advancing Treatment for Pediatric Craniopharyngioma Consortium, we interrogated potential age-related transcriptional differences using several rigorous mathematical analyses. These included: canonical differential expression analysis; divisive, agglomerative, and probabilistic based hierarchical clustering; information theory based characterizations; and the deep learning approach, HD Spot. Our work indicates that there is no therapeutically relevant difference in ACP gene expression based on age. As such, potential therapeutic targets identified in pediatric ACP are also likely to have relvance for adult patients.

BACKGROUND:Surgical site infections (SSIs) are one of the most common complications following pediatric complex tethered spinal cord release. This patient population is similar in some ways to the neuromuscular scoliosis population, in which higher-than-expected rates of gram-negative SSIs have been identified. METHODS:We conducted a single-center retrospective chart review of all patients who underwent complex tethered spinal cord release over a 10-year period between 2007 and 2017. RESULTS:A total of 69 patients were identified, with 10 documented SSIs (14%). 50% of the SSIs were polymicrobial or included at least 1 gram-negative organism. Among the organisms isolated, 3 were fully or -partially resistant to cefazolin, the most common antibiotic prophylaxis in this population. CONCLUSION/CONCLUSIONS:Among children undergoing complex tethered spinal cord release, gram-negative and polymicrobial infections are a significant cause of SSIs. Although further multicenter data are needed, these findings suggest that standard antibiotic prophylaxis with cefazolin may not be sufficient.

PURPOSE:Children with myelomeningocele (MMC) are at increased risk of developing neuromuscular scoliosis and spinal cord re-tethering (Childs Nerv Syst 12:748-754, 1996; Neurosurg Focus 16:2, 2004; Neurosurg Focus 29:1, 2010). Some centers perform prophylactic untethering on asymptomatic MMC patients prior to scoliosis surgery because of concern that additional traction on the cord may place the patient at greater risk of neurologic deterioration peri-operatively. However, prophylactic untethering may not be justified if it carries increased surgical risks. The purpose of this study was to determine if prophylactic untethering is necessary in asymptomatic children with MMC undergoing scoliosis surgery. METHODS:A multidisciplinary, retrospective cohort study from seven children's hospitals was performed including asymptomatic children with MMC < 21 years old, managed with or without prophylactic untethering prior to scoliosis surgery. Patients were divided into three groups for analysis: (1) untethering at the time of scoliosis surgery (concomitant untethering), (2) untethering within 3 months of scoliosis surgery (prior untethering), and (3) no prophylactic untethering. Baseline data, intra-operative reports, and 90-day post-operative outcomes were analyzed to assess for differences in neurologic outcomes, surgical complications, and overall length of stay. RESULTS:A total of 208 patients were included for analysis (mean age 9.4 years, 52% girls). No patient in any of the groups exhibited worsened motor or sensory function at 90 days post-operatively. However, comparing the prophylactic untethering groups with the group that was not untethered, there was an increased risk of surgical site infection (SSI) (31.3% concomitant, 28.6% prior untethering vs. 12.3% no untethering; p = 0.0104), return to the OR (43.8% concomitant, 23.8% prior untethering vs. 17.4% no untethering; p = 0.0047), need for blood transfusion (51.6% concomitant, 57.1% prior untethering vs. 33.8% no untethering; p = 0.04), and increased mean length of stay (LOS) (13.4 days concomitant, 10.6 days prior untethering vs. 6.8 days no untethering; p < 0.0001). In multivariable logistic regression analysis, prophylactic untethering was independently associated with increased adjusted relative risks of surgical site infection (aRR = 2.65, 95% CI 1.17-5.02), unplanned re-operation (aRR = 2.17, 95% CI 1.02-4.65), and any complication (aRR = 2.25, 95% CI 1.07-4.74). CONCLUSION:In this study, asymptomatic children with myelomeningocele who underwent scoliosis surgery developed no neurologic injuries regardless of prophylactic untethering. However, those who underwent prophylactic untethering were more likely to experience SSIs, return to the OR, need a blood transfusion, and have increased LOS than children not undergoing untethering. Based on these data, prophylactic untethering in asymptomatic MMC patients prior to scoliosis surgery does not provide any neurological benefit and is associated with increased surgical risks.

OBJECTIVE:Hypermobility of the craniocervical junction (CCJ) in patients with Down syndrome (DS) is common. Whereas atlantoaxial (C1-2) hypermobility is well characterized, occipitoatlantal (Oc-C1) laxity is recognized but poorly defined. A clear understanding of the risks associated with DS-related hypermobility is lacking. Research efforts to address the topic of axial cervical spine instability in the patient with DS require a reliable and reproducible means of assessing CCJ mobility. The authors conducted a pilot study comparing two methods of quantifying motion of the CCJ on dynamic (flexion/extension) plain radiographs: the delta-condyle-axial interval (ΔCAI) and the delta-basion-axial interval (ΔBAI) methods. METHODS:Dynamic radiographs from a cohort of 10 patients with DS were evaluated according to prescribed standards. Independent movement of Oc-C1, C1-2, and Oc-C2 was calculated. Interrater and intrarater reliability for CCJ mobility was then calculated for both techniques. RESULTS:Measurement using the ΔCAI technique had excellent fidelity with intraclass correlation coefficients (ICCs) of 0.77, 0.71, and 0.80 for Oc-C1, C1-2, and Oc-C2, respectively. The ΔBAI technique had lower fidelity, yielding respective ICCs of 0.61, 0.65, and 0.50. CONCLUSIONS:This pilot study suggests that ΔCAI is a superior measurement technique compared to ΔBAI and may provide reliable assessment of the mobility of the CCJ on dynamic radiographs in the pediatric patient with DS. The use of reliable and reproducible measurement techniques strengthens the validity of research derived from pooled database efforts.

OBJECTIVE:Scoliosis is frequently a presenting sign of Chiari malformation type I (CM-I) with syrinx. The authors' goal was to define scoliosis in this population and describe how radiological characteristics of CM-I and syrinx relate to the presence and severity of scoliosis. METHODS:A large multicenter retrospective and prospective registry of pediatric patients with CM-I (tonsils ≥ 5 mm below the foramen magnum) and syrinx (≥ 3 mm in axial width) was reviewed for clinical and radiological characteristics of CM-I, syrinx, and scoliosis (coronal curve ≥ 10°). RESULTS:Based on available imaging of patients with CM-I and syrinx, 260 of 825 patients (31%) had a clear diagnosis of scoliosis based on radiographs or coronal MRI. Forty-nine patients (5.9%) did not have scoliosis, and in 516 (63%) patients, a clear determination of the presence or absence of scoliosis could not be made. Comparison of patients with and those without a definite scoliosis diagnosis indicated that scoliosis was associated with wider syrinxes (8.7 vs 6.3 mm, OR 1.25, p < 0.001), longer syrinxes (10.3 vs 6.2 levels, OR 1.18, p < 0.001), syrinxes with their rostral extent located in the cervical spine (94% vs 80%, OR 3.91, p = 0.001), and holocord syrinxes (50% vs 16%, OR 5.61, p < 0.001). Multivariable regression analysis revealed syrinx length and the presence of holocord syrinx to be independent predictors of scoliosis in this patient cohort. Scoliosis was not associated with sex, age at CM-I diagnosis, tonsil position, pB-C2 distance (measured perpendicular distance from the ventral dura to a line drawn from the basion to the posterior-inferior aspect of C2), clivoaxial angle, or frontal-occipital horn ratio. Average curve magnitude was 29.9°, and 37.7% of patients had a left thoracic curve. Older age at CM-I or syrinx diagnosis (p < 0.0001) was associated with greater curve magnitude whereas there was no association between syrinx dimensions and curve magnitude. CONCLUSIONS:Syrinx characteristics, but not tonsil position, were related to the presence of scoliosis in patients with CM-I, and there was an independent association of syrinx length and holocord syrinx with scoliosis. Further study is needed to evaluate the nature of the relationship between syrinx and scoliosis in patients with CM-I.