Faculty Bibliography

OBJECTIVE:Current understanding of how the pediatric craniocervical junction develops remains incomplete. Measurements of anatomical relationships at the craniocervical junction can influence clinical and surgical decision-making. The purpose of this analysis was to quantitatively define clinically relevant craniocervical junction measurements in a population of children with CT scans that show normal anatomy. METHODS:A total of 1458 eligible patients were identified from children between 1 and 18 years of age who underwent cervical spine CT scanning at a single institution. Patients were separated by both sex and age in years into 34 groups. Following this, patients within each group were randomly selected for inclusion until a target of 15 patients in each group had been reached. Each patient underwent measurement of the occipital condyle-C1 interval (CCI), pB-C2, atlantodental interval (ADI), basion-dens interval (BDI), basion-opisthion diameter (BOD), basion-axial interval (BAI), dens angulation, and canal diameter at C1. Mean values were calculated in each group. Each measurement was performed by two teams and compared for intraclass correlation coefficient (ICC). RESULTS:The data showed that CCI, ADI, BDI, and dens angulation decrease in magnitude throughout childhood, while pB-C2, PADI, BAI, and BOD increase throughout childhood, with an ICC of fair to good (range 0.413-0.912). Notably, CCI decreases continuously on coronal CT scans, whereas on parasagittal CT scans, CCI does not decrease until after age 9, when it shows a continuous decline similar to measurements on coronal CT scans. CONCLUSIONS:These morphometric analyses establish parameters for normal pediatric craniocervical spine growth for each year of life up to 18 years. The data should be considered when evaluating children for potential surgical intervention.

The early principles of spinal fusion in the adolescent population focused on preventing progression while simultaneously correcting the spinal deformity. These principles have remained relatively unchanged since their introduction more than a century ago, but recent improvements in imaging, instrumentation, and corrective techniques have provided new insight on the diagnosis, management, and postoperative care of this condition. Treatment options for the management of patients with early onset scoliosis have also evolved dramatically over the last 2 decades. Further knowledge on the physiology of lung development and the detrimental effects of early fusion in the early onset scoliosis population has led to the development of growth friendly implants and other surgical techniques that allow correction of the deformity while maintaining spine, lung, and chest wall development. The following is an overview of current techniques on the management of adolescent idiopathic and early onset scoliosis to help provide guidance on the available surgical alternatives to address these conditions.

Cerebral vasospasm is associated with significant morbidity, and most commonly occurs following subarachnoid hemorrhage. Rarely, vasospasm can follow tumor resection and traumatic brain injury. We present the first reported case of a young child who developed diffuse vasospasm following open fenestration of an arachnoid cyst and was promptly treated, with full recovery of neurologic function. Although vasopasm after arachnoid cyst fenestration is rare, it can be included in the differential for a new focal neurologic deficit.

BACKGROUND:Occipitocervical distraction injuries (OCDI) in children occur on a wide spectrum of severity, and decisions about treatment suffer from a lack of rigorous guidelines and significant inter-institutional variability. While clear cases of frank atlanto-occipital dislocation (AOD) are treated with surgical stabilization, the approach for less severe cases of OCDI is not standardized. These patients require a careful assessment of both radiographic and clinical criteria, as part of a complex risk-benefit analysis, to establish whether occipitocervical fusion (OCF) is indicated. Here, we performed a systematic review of the literature that describes traumatic OCDI in children < 18 years of age. SUMMARY/CONCLUSIONS:We performed a systematic review, according to PRISMA guidelines, of children < 18 years of age presenting with traumatic etiologies of OCDI. We searched PubMed to identify papers congruent with these criteria. Exclusion criteria included (1) reports on atraumatic causes of OCDI and (2) studies with insufficient clinical and radiographic details on individual patients. We identified 16 reports describing a total of 144 patients treated for pediatric traumatic OCDI. Based on the synthesis of these findings and the collective experience of the authors, we present the demographic, clinical, and radiographic factors that underlie OC instability, which we hope will serve as components of a grading system in the future. We considered various clinical and radiographic findings including: (1) the mechanism of injury, (2) the patient's age, (3) CT/CT angiography of head and neck findings and parameters, (4) MRI findings, and (5) neurological exam, for the purpose of determining the severity of the OCDI and offering treatment guidelines based on the summative risk of underlying OC instability. Key Messages: OCDI is a potentially devastating injury, especially in children. Although missing the diagnosis can have potentially catastrophic consequences, reverting to surgical fixation in less severe cases can subject children to unnecessary operative risk and permanently reduce their range of motion. After reviewing all the available reports of pediatric traumatic OCDI in the neurosurgical literature, we propose an outline of clinical and radiographic factors influencing underlying OC instability that could be incorporated into a grading scale to guide treatment. We hope this study stimulates discussion on the standardization of treatment for pediatric OCDI.

OBJECTIVEComplications after complex tethered spinal cord (cTSC) surgery include infections and cerebrospinal fluid (CSF) leaks. With little empirical evidence to guide management, there is variability in the interventions undertaken to limit complications. Expert-based best practices may improve the care of patients undergoing cTSC surgery. Here, authors conducted a study to identify consensus-driven best practices.METHODSThe Delphi method was employed to identify consensual best practices. A literature review regarding cTSC surgery together with a survey of current practices was distributed to 17 board-certified pediatric neurosurgeons. Thirty statements were then formulated and distributed to the group. Results of the second survey were discussed during an in-person meeting leading to further consensus, which was defined as ≥ 80% agreement on a 4-point Likert scale (strongly agree, agree, disagree, strongly disagree).RESULTSSeventeen consensus-driven best practices were identified, with all participants willing to incorporate them into their practice. There were four preoperative interventions: (1, 2) asymptomatic AND symptomatic patients should be referred to urology preoperatively, (3, 4) routine preoperative urine cultures are not necessary for asymptomatic AND symptomatic patients. There were nine intraoperative interventions: (5) patients should receive perioperative cefazolin or an equivalent alternative in the event of allergy, (6) chlorhexidine-based skin preparation is the preferred regimen, (7) saline irrigation should be used intermittently throughout the case, (8) antibiotic-containing irrigation should be used following dural closure, (9) a nonlocking running suture technique should be used for dural closure, (10) dural graft overlay should be used when unable to obtain primary dural closure, (11) an expansile dural graft should be incorporated in cases of lipomyelomeningocele in which primary dural closure does not permit free flow of CSF, (12) paraxial muscles should be closed as a layer separate from the fascia, (13) routine placement of postoperative drains is not necessary. There were three postoperative interventions: (14) postoperative antibiotics are an option and, if given, should be discontinued within 24 hours; (15) patients should remain flat for at least 24 hours postoperatively; (16) routine use of abdominal binders or other compressive devices postoperatively is not necessary. One intervention was prioritized for additional study: (17) further study of additional gram-negative perioperative coverage is needed.CONCLUSIONSA modified Delphi technique was used to develop consensus-driven best practices for decreasing wound complications after cTSC surgery. Further study is required to determine if implementation of these practices will lead to reduced complications. Discussion through the course of this study resulted in the initiation of a multicenter study of gram-negative surgical site infections in cTSC surgery.

OBJECTIVEThe authors created a collaborative network, the Synostosis Research Group (SynRG), to facilitate multicenter clinical research on craniosynostosis. To identify common and differing practice patterns within the network, they assessed the SynRG surgeons' management preferences for sagittal synostosis. These results will be incorporated into planning cooperative studies.METHODSThe SynRG consists of 12 surgeons at 5 clinical sites. An email survey was distributed to SynRG surgeons in late 2016, and responses were collected through early 2017. Responses were collated and analyzed descriptively.RESULTSAll of the surgeons-7 plastic/craniofacial surgeons and 5 neurosurgeons-completed the survey. They varied in both experience (1-24 years) and sagittal synostosis case volume in the preceding year (5-45 cases). Three sites routinely perform preoperative CT scans. The preferred surgical technique for children younger than 3 months is strip craniectomy (10/12 surgeons), whereas children older than 6 months are all treated with open cranial vault surgery. Pre-incision cefazolin, preoperative complete blood count panels, and an arterial line were used by most surgeons, but tranexamic acid was used routinely at 3 sites and never at the other 2 sites. Among surgeons performing endoscopic strip craniectomy surgery (SCS), most create a 5-cm-wide craniectomy, whereas 2 surgeons create a 2-cm strip. Four surgeons routinely send endoscopic SCS patients to the intensive care unit after surgery. Two of the 5 sites routinely obtain a CT scan within the 1st year after surgery.CONCLUSIONSThe SynRG surgeons vary substantially in the use of imaging, the choice of surgical procedure and technique, and follow-up. A collaborative network will provide the opportunity to study different practice patterns, reduce variation, and contribute multicenter data on the management of children with craniosynostosis.

BACKGROUND:Fusion rates following rigid internal instrumentation for occipitocervical and atlantoaxial instability approach 100% in many reports. Based on this success and the morbidity that can be associated with obtaining autograft for fusion, surgeons increasingly select alternative graft materials. OBJECTIVE:To examine fusion failure using various graft materials in a retrospective observational study. METHODS:Insurance claims databases (Truven Health MarketScan® [Truven Health Analytics, Ann Arbor, Michigan] and IMS Health Lifelink/PHARMetrics [IMS Health, Danbury, Connecticut]) were used to identify patients with CPT codes 22590 and 22595. Patients were divided by age (≥18 yr = adult) and arthrodesis code, establishing 4 populations. Each population was further separated by graft code: group 1 = 20938 (structural autograft); group 2 = 20931 (structural allograft); group 3 = other graft code (nonstructural); group 4 = no graft code. Fusion failure was assigned when ≥1 predetermined codes presented in the record ≥90 d following the last surgical procedure. RESULTS:Of 522 patients identified, 419 were adult and 103 were pediatric. Fusion failure occurred in 10.9% (57/522) of the population. There was no statistically significant difference in fusion failure based on graft material. Fusion failure occurred in 18.9% of pediatric occipitocervical fusions, but in 9.2% to 11.1% in the other groups. CONCLUSION:Administrative data regarding patients who underwent instrumented occipitocervical or atlantoaxial arthrodesis do not demonstrate differences in fusion rates based on the graft material selected. When compared to many contemporary primary datasets, fusion failure was more frequent; however, several recent studies have shown higher failure rates than previously reported. This may be influenced by broad patient selection and fusion failure criteria that were selected in order to maximize the generalizability of the findings.

OBJECTIVE The long-term effects of surgical fusion on the growing subaxial cervical spine are largely unknown. Recent cross-sectional studies have demonstrated that there is continued growth of the cervical spine through the teenage years. The purpose of this multicenter study was to determine the effects of rigid instrumentation and fusion on the growing subaxial cervical spine by investigating vertical growth, cervical alignment, cervical curvature, and adjacent-segment instability over time. METHODS A total of 15 centers participated in this multi-institutional retrospective study. Cases involving children less than 16 years of age who underwent rigid instrumentation and fusion of the subaxial cervical spine (C-2 and T-1 inclusive) with at least 1 year of clinical and radiographic follow-up were investigated. Charts were reviewed for clinical data. Postoperative and most recent radiographs, CT, and MR images were used to measure vertical growth and assess alignment and stability. RESULTS Eighty-one patients were included in the study, with a mean follow-up of 33 months. Ninety-five percent of patients had complete clinical resolution or significant improvement in symptoms. Postoperative cervical kyphosis was seen in only 4 patients (5%), and none developed a swan-neck deformity, unintended adjacent-level fusion, or instability. Of patients with at least 2 years of follow-up, 62% demonstrated growth across the fusion construct. On average, vertical growth was 79% (4-level constructs), 83% (3-level constructs), or 100% (2-level constructs) of expected growth. When comparing the group with continued vertical growth to the one without growth, there were no statistically significant differences in terms of age, sex, underlying etiology, surgical approach, or number of levels fused. CONCLUSIONS Continued vertical growth of the subaxial spine occurs in nearly two-thirds of children after rigid instrumentation and fusion of the subaxial spine. Failure of continued vertical growth is not associated with the patient's age, sex, underlying etiology, number of levels fused, or surgical approach. Further studies are needed to understand this dichotomy and determine the long-term biomechanical effects of surgery on the growing pediatric cervical spine.