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Douglas L. Brockmeyer, Samuel H. Cheshier, Jeff Stevens, Julio C. Facelli, Kerry Rowe, John D. Heiss, Anthony Musolf, David H. Viskochil, Kristina L. Allen-Brady, and Lisa A. Cannon-Albright

OBJECTIVE

Inherited variants predisposing patients to type 1 or 1.5 Chiari malformation (CM) have been hypothesized but have proven difficult to confirm. The authors used a unique high-risk pedigree population resource and approach to identify rare candidate variants that likely predispose individuals to CM and protein structure prediction tools to identify pathogenicity mechanisms.

METHODS

By using the Utah Population Database, the authors identified pedigrees with significantly increased numbers of members with CM diagnosis. From a separate DNA biorepository of 451 samples from CM patients and families, 32 CM patients belonging to 1 or more of 24 high-risk Chiari pedigrees were identified. Two high-risk pedigrees had 3 CM-affected relatives, and 22 pedigrees had 2 CM-affected relatives. To identify rare candidate predisposition gene variants, whole-exome sequence data from these 32 CM patients belonging to 24 CM-affected related pairs from high-risk pedigrees were analyzed. The I-TASSER package for protein structure prediction was used to predict the structures of both the wild-type and mutant proteins found here.

RESULTS

Sequence analysis of the 24 affected relative pairs identified 38 rare candidate Chiari predisposition gene variants that were shared by at least 1 CM-affected pair from a high-risk pedigree. The authors found a candidate variant in HOXC4 that was shared by 2 CM-affected patients in 2 independent pedigrees. All 4 of these CM cases, 2 in each pedigree, exhibited a specific craniocervical bony phenotype defined by a clivoaxial angle less than 125°. The protein structure prediction results suggested that the mutation considered here may reduce the binding affinity of HOXC4 to DNA.

CONCLUSIONS

Analysis of unique and powerful Utah genetic resources allowed identification of 38 strong candidate CM predisposition gene variants. These variants should be pursued in independent populations. One of the candidates, a rare HOXC4 variant, was identified in 2 high-risk CM pedigrees, with this variant possibly predisposing patients to a Chiari phenotype with craniocervical kyphosis.

Free access

*Yosef M. Dastagirzada, Nikita G. Alexiades, David B. Kurland, Sebastián N. Anderson, Douglas L. Brockmeyer, David B. Bumpass, Sandip Chatterjee, Mari L. Groves, Todd C. Hankinson, David Harter, Daniel Hedequist, Andrew Jea, Jeffrey R. Leonard, Jonathan E. Martin, Matthew E. Oetgen, Joshua Pahys, Curtis Rozzelle, Jennifer M. Strahle, Dominic Thompson, Burt Yaszay, and Richard C. E. Anderson

OBJECTIVE

Cervical spine disorders in children are relatively uncommon; therefore, paradigms for surgical and nonsurgical clinical management are not well established. The purpose of this study was to bring together an international, multidisciplinary group of pediatric cervical spine experts to build consensus via a modified Delphi approach regarding the clinical management of children with cervical spine disorders and those undergoing cervical spine stabilization surgery.

METHODS

A modified Delphi method was used to identify consensus statements for the management of children with cervical spine disorders requiring stabilization. A survey of current practices, supplemented by a literature review, was electronically distributed to 17 neurosurgeons and orthopedic surgeons experienced with the clinical management of pediatric cervical spine disorders. Subsequently, 52 summary statements were formulated and distributed to the group. Statements that reached near consensus or that were of particular interest were then discussed during an in-person meeting to attain further consensus. Consensus was defined as ≥ 80% agreement on a 4-point Likert scale (strongly agree, agree, disagree, strongly disagree).

RESULTS

Forty-five consensus-driven statements were identified, with all participants willing to incorporate them into their practice. For children with cervical spine disorders and/or stabilization, consensus statements were divided into the following categories: A) preoperative planning (12 statements); B) radiographic thresholds of instability (4); C) intraoperative/perioperative management (15); D) postoperative care (11); and E) nonoperative management (3). Several important statements reaching consensus included the following recommendations: 1) to obtain pre-positioning baseline signals with intraoperative neuromonitoring; 2) to use rigid instrumentation when technically feasible; 3) to provide postoperative external immobilization for 6–12 weeks with a rigid cervical collar rather than halo vest immobilization; and 4) to continue clinical postoperative follow-up at least until anatomical cervical spine maturity was reached. In addition, preoperative radiographic thresholds for instability that reached consensus included the following: 1) translational motion ≥ 5 mm at C1–2 (excluding patients with Down syndrome) or ≥ 4 mm in the subaxial spine; 2) dynamic angulation in the subaxial spine ≥ 10°; and 3) abnormal motion and T2 signal change on MRI seen at the same level.

CONCLUSIONS

In this study, the authors have demonstrated that a multidisciplinary, international group of pediatric cervical spine experts was able to reach consensus on 45 statements regarding the management of pediatric cervical spine disorders and stabilization. Further study is required to determine if implementation of these practices can lead to reduced complications and improved outcomes for children.

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Karol P. Budohoski, Raj Thakrar, Zoya Voronovich, Robert C. Rennert, Craig Kilburg, Ramesh Grandhi, William T. Couldwell, Douglas L. Brockmeyer, and Philipp Taussky

OBJECTIVE

Flow-diverting devices have been used successfully for the treatment of complex intracranial vascular injuries in adults, but the role of these devices in treating iatrogenic and traumatic intracranial vascular injuries in children remains unclear. The authors present their experience using the Pipeline embolization device (PED) for treating intracranial pseudoaneurysms in children.

METHODS

This single-center retrospective cohort study included pediatric patients with traumatic and iatrogenic injuries to the intracranial vasculature that were treated with the PED between 2015 and 2021. Demographic data, indications for treatment, the number and sizes of PEDs used, follow-up imaging, and clinical outcomes were analyzed.

RESULTS

Six patients with a median age of 12 years (range 7–16 years) underwent PED placement to treat intracranial pseudoaneurysms. There were 3 patients with hemorrhagic presentation, 2 with ischemia, and 1 in whom a growing pseudoaneurysm was found on angiography. Injured vessels included the anterior cerebral artery (n = 2), the supraclinoid internal carotid artery (ICA, n = 2), the cavernous ICA (n = 1), and the distal cervical ICA (n = 1). All 6 pseudoaneurysms were successfully treated with PED deployment. One patient required re-treatment with a second PED within a week because of concern for a growing pseudoaneurysm. One patient experienced parent vessel occlusion without neurological sequelae.

CONCLUSIONS

Use of the PED is feasible for the management of iatrogenic and traumatic pseudoaneurysms of the intracranial vasculature in children, even in the setting of hemorrhagic presentation.

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Nikita G. Alexiades, Belinda Shao, Edward S. Ahn, Jeffrey P. Blount, Douglas L. Brockmeyer, Todd C. Hankinson, Cody L. Nesvick, David I. Sandberg, Gregory G. Heuer, Lisa Saiman, Neil A. Feldstein, and Richard C. E. Anderson

OBJECTIVE

Complex tethered spinal cord (cTSC) release in children is often complicated by surgical site infection (SSI). Children undergoing this surgery share many similarities with patients undergoing correction for neuromuscular scoliosis, where high rates of gram-negative and polymicrobial infections have been reported. Similar organisms isolated from SSIs after cTSC release were recently demonstrated in a single-center pilot study. The purpose of this investigation was to determine if these findings are reproducible across a larger, multicenter study.

METHODS

A multicenter, retrospective chart review including 7 centers was conducted to identify all cases of SSI following cTSC release during a 10-year study period from 2007 to 2017. Demographic information along with specific microbial culture data and antibiotic sensitivities for each cultured organism were collected.

RESULTS

A total of 44 SSIs were identified from a total of 655 cases, with 78 individual organisms isolated. There was an overall SSI rate of 6.7%, with 43% polymicrobial and 66% containing at least one gram-negative organism. Half of SSIs included an organism that was resistant to cefazolin, whereas only 32% of SSIs were completely susceptible to cefazolin.

CONCLUSIONS

In this study, gram-negative and polymicrobial infections were responsible for the majority of SSIs following cTSC surgery, with approximately half resistant to cefazolin. Broader gram-negative antibiotic prophylaxis should be considered for this patient population.

Free access

S. Hassan A. Akbari, Alexander T. Yahanda, Laurie L. Ackerman, P. David Adelson, Raheel Ahmed, Gregory W. Albert, Philipp R. Aldana, Tord D. Alden, Richard C. E. Anderson, David F. Bauer, Tammy Bethel-Anderson, Karin Bierbrauer, Douglas L. Brockmeyer, Joshua J. Chern, Daniel E. Couture, David J. Daniels, Brian J. Dlouhy, Susan R. Durham, Richard G. Ellenbogen, Ramin Eskandari, Herbert E. Fuchs, Gerald A. Grant, Patrick C. Graupman, Stephanie Greene, Jeffrey P. Greenfield, Naina L. Gross, Daniel J. Guillaume, Todd C. Hankinson, Gregory G. Heuer, Mark Iantosca, Bermans J. Iskandar, Eric M. Jackson, George I. Jallo, James M. Johnston, Bruce A. Kaufman, Robert F. Keating, Nicklaus R. Khan, Mark D. Krieger, Jeffrey R. Leonard, Cormac O. Maher, Francesco T. Mangano, J. Gordon McComb, Sean D. McEvoy, Thanda Meehan, Arnold H. Menezes, Michael S. Muhlbauer, Brent R. O’Neill, Greg Olavarria, John Ragheb, Nathan R. Selden, Manish N. Shah, Chevis N. Shannon, Joshua S. Shimony, Matthew D. Smyth, Scellig S. D. Stone, Jennifer M. Strahle, Mandeep S. Tamber, James C. Torner, Gerald F. Tuite, Elizabeth C. Tyler-Kabara, Scott D. Wait, John C. Wellons III, William E. Whitehead, Tae Sung Park, and David D. Limbrick Jr.

OBJECTIVE

The aim of this study was to determine differences in complications and outcomes between posterior fossa decompression with duraplasty (PFDD) and without duraplasty (PFD) for the treatment of pediatric Chiari malformation type I (CM1) and syringomyelia (SM).

METHODS

The authors used retrospective and prospective components of the Park-Reeves Syringomyelia Research Consortium database to identify pediatric patients with CM1-SM who received PFD or PFDD and had at least 1 year of follow-up data. Preoperative, treatment, and postoperative characteristics were recorded and compared between groups.

RESULTS

A total of 692 patients met the inclusion criteria for this database study. PFD was performed in 117 (16.9%) and PFDD in 575 (83.1%) patients. The mean age at surgery was 9.86 years, and the mean follow-up time was 2.73 years. There were no significant differences in presenting signs or symptoms between groups, although the preoperative syrinx size was smaller in the PFD group. The PFD group had a shorter mean operating room time (p < 0.0001), fewer patients with > 50 mL of blood loss (p = 0.04), and shorter hospital stays (p = 0.0001). There were 4 intraoperative complications, all within the PFDD group (0.7%, p > 0.99). Patients undergoing PFDD had a 6-month complication rate of 24.3%, compared with 13.7% in the PFD group (p = 0.01). There were no differences between groups for postoperative complications beyond 6 months (p = 0.33). PFD patients were more likely to require revision surgery (17.9% vs 8.3%, p = 0.002). PFDD was associated with greater improvements in headaches (89.6% vs 80.8%, p = 0.04) and back pain (86.5% vs 59.1%, p = 0.01). There were no differences between groups for improvement in neurological examination findings. PFDD was associated with greater reduction in anteroposterior syrinx size (43.7% vs 26.9%, p = 0.0001) and syrinx length (18.9% vs 5.6%, p = 0.04) compared with PFD.

CONCLUSIONS

PFD was associated with reduced operative time and blood loss, shorter hospital stays, and fewer postoperative complications within 6 months. However, PFDD was associated with better symptom improvement and reduction in syrinx size and lower rates of revision decompression. The two surgeries have low intraoperative complication rates and comparable complication rates beyond 6 months.

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Syed Hassan A. Akbari, Asad A. Rizvi, Travis S. CreveCoeur, Rowland H. Han, Jacob K. Greenberg, James Torner, Douglas L. Brockmeyer, John C. Wellons III, Jeffrey R. Leonard, Francesco T. Mangano, James M. Johnston, Manish N. Shah, Bermans J. Iskandar, Raheel Ahmed, Gerald F. Tuite, Bruce A. Kaufman, David J. Daniels, Eric M. Jackson, Gerald A. Grant, Alexander K. Powers, Daniel E. Couture, P. David Adelson, Tord D. Alden, Philipp R. Aldana, Richard C. E. Anderson, Nathan R. Selden, Karin Bierbrauer, William Boydston, Joshua J. Chern, William E. Whitehead, Robert C. Dauser, Richard G. Ellenbogen, Jeffrey G. Ojemann, Herbert E. Fuchs, Daniel J. Guillaume, Todd C. Hankinson, Brent R. O’Neill, Mark Iantosca, W. Jerry Oakes, Robert F. Keating, Paul Klimo Jr., Michael S. Muhlbauer, J. Gordon McComb, Arnold H. Menezes, Nickalus R. Khan, Toba N. Niazi, John Ragheb, Chevis N. Shannon, Jodi L. Smith, Laurie L. Ackerman, Andrew H. Jea, Cormac O. Maher, Prithvi Narayan, Gregory W. Albert, Scellig S. D. Stone, Lissa C. Baird, Naina L. Gross, Susan R. Durham, Stephanie Greene, Robert C. McKinstry, Joshua S. Shimony, Jennifer M. Strahle, Matthew D. Smyth, Ralph G. Dacey Jr., Tae Sung Park, and David D. Limbrick Jr.

OBJECTIVE

The goal of this study was to assess the social determinants that influence access and outcomes for pediatric neurosurgical care for patients with Chiari malformation type I (CM-I) and syringomyelia (SM).

METHODS

The authors used retro- and prospective components of the Park-Reeves Syringomyelia Research Consortium database to identify pediatric patients with CM-I and SM who received surgical treatment and had at least 1 year of follow-up data. Race, ethnicity, and insurance status were used as comparators for preoperative, treatment, and postoperative characteristics and outcomes.

RESULTS

A total of 637 patients met inclusion criteria, and race or ethnicity data were available for 603 (94.7%) patients. A total of 463 (76.8%) were non-Hispanic White (NHW) and 140 (23.2%) were non-White. The non-White patients were older at diagnosis (p = 0.002) and were more likely to have an individualized education plan (p < 0.01). More non-White than NHW patients presented with cerebellar and cranial nerve deficits (i.e., gait ataxia [p = 0.028], nystagmus [p = 0.002], dysconjugate gaze [p = 0.03], hearing loss [p = 0.003], gait instability [p = 0.003], tremor [p = 0.021], or dysmetria [p < 0.001]). Non-White patients had higher rates of skull malformation (p = 0.004), platybasia (p = 0.002), and basilar invagination (p = 0.036). Non-White patients were more likely to be treated at low-volume centers than at high-volume centers (38.7% vs 15.2%; p < 0.01). Non-White patients were older at the time of surgery (p = 0.001) and had longer operative times (p < 0.001), higher estimated blood loss (p < 0.001), and a longer hospital stay (p = 0.04). There were no major group differences in terms of treatments performed or complications. The majority of subjects used private insurance (440, 71.5%), whereas 175 (28.5%) were using Medicaid or self-pay. Private insurance was used in 42.2% of non-White patients compared to 79.8% of NHW patients (p < 0.01). There were no major differences in presentation, treatment, or outcome between insurance groups. In multivariate modeling, non-White patients were more likely to present at an older age after controlling for sex and insurance status (p < 0.01). Non-White and male patients had a longer duration of symptoms before reaching diagnosis (p = 0.033 and 0.004, respectively).

CONCLUSIONS

Socioeconomic and demographic factors appear to influence the presentation and management of patients with CM-I and SM. Race is associated with age and timing of diagnosis as well as operating room time, estimated blood loss, and length of hospital stay. This exploration of socioeconomic and demographic barriers to care will be useful in understanding how to improve access to pediatric neurosurgical care for patients with CM-I and SM.

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Sean M. Finley, J. Harley Astin, Evan Joyce, Andrew T. Dailey, Douglas L. Brockmeyer, and Benjamin J. Ellis

OBJECTIVE

The underlying biomechanical differences between the pediatric and adult cervical spine are incompletely understood. Computational spine modeling can address that knowledge gap. Using a computational method known as finite element modeling, the authors describe the creation and evaluation of a complete pediatric cervical spine model.

METHODS

Using a thin-slice CT scan of the cervical spine from a 5-year-old boy, a 3D model was created for finite element analysis. The material properties and boundary and loading conditions were created and model analysis performed using open-source software. Because the precise material properties of the pediatric cervical spine are not known, a published parametric approach of scaling adult properties by 50%, 25%, and 10% was used. Each scaled finite element model (FEM) underwent two types of simulations for pediatric cadaver testing (axial tension and cardinal ranges of motion [ROMs]) to assess axial stiffness, ROM, and facet joint force (FJF). The authors evaluated the axial stiffness and flexion-extension ROM predicted by the model using previously published experimental measurements obtained from pediatric cadaveric tissues.

RESULTS

In the axial tension simulation, the model with 50% adult ligamentous and annulus material properties predicted an axial stiffness of 49 N/mm, which corresponded with previously published data from similarly aged cadavers (46.1 ± 9.6 N/mm). In the flexion-extension simulation, the same 50% model predicted an ROM that was within the range of the similarly aged cohort of cadavers. The subaxial FJFs predicted by the model in extension, lateral bending, and axial rotation were in the range of 1–4 N and, as expected, tended to increase as the ligament and disc material properties decreased.

CONCLUSIONS

A pediatric cervical spine FEM was created that accurately predicts axial tension and flexion-extension ROM when ligamentous and annulus material properties are reduced to 50% of published adult properties. This model shows promise for use in surgical simulation procedures and as a normal comparison for disease-specific FEMs.

Free access

Brooke Sadler, Alex Skidmore, Jordan Gewirtz, Richard C. E. Anderson, Gabe Haller, Laurie L. Ackerman, P. David Adelson, Raheel Ahmed, Gregory W. Albert, Philipp R. Aldana, Tord D. Alden, Christine Averill, Lissa C. Baird, David F. Bauer, Tammy Bethel-Anderson, Karin S. Bierbrauer, Christopher M. Bonfield, Douglas L. Brockmeyer, Joshua J. Chern, Daniel E. Couture, David J. Daniels, Brian J. Dlouhy, Susan R. Durham, Richard G. Ellenbogen, Ramin Eskandari, Herbert E. Fuchs, Timothy M. George, Gerald A. Grant, Patrick C. Graupman, Stephanie Greene, Jeffrey P. Greenfield, Naina L. Gross, Daniel J. Guillaume, Todd C. Hankinson, Gregory G. Heuer, Mark Iantosca, Bermans J. Iskandar, Eric M. Jackson, Andrew H. Jea, James M. Johnston, Robert F. Keating, Nickalus Khan, Mark D. Krieger, Jeffrey R. Leonard, Cormac O. Maher, Francesco T. Mangano, Timothy B. Mapstone, J. Gordon McComb, Sean D. McEvoy, Thanda Meehan, Arnold H. Menezes, Michael Muhlbauer, W. Jerry Oakes, Greg Olavarria, Brent R. O’Neill, John Ragheb, Nathan R. Selden, Manish N. Shah, Chevis N. Shannon, Jodi Smith, Matthew D. Smyth, Scellig S. D. Stone, Gerald F. Tuite, Scott D. Wait, John C. Wellons III, William E. Whitehead, Tae Sung Park, David D. Limbrick Jr., and Jennifer M. Strahle

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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