Sponseller, Paul D.

Case: Fibrodysplasia ossificans progressiva (FOP) is a rare genetic disorder characterized by progressive heterotopic ossification. Scoliosis may develop and progress rapidly, especially during adolescence. We report 4 patients with FOP and scoliosis during early adolescence: A 12-year-old girl underwent T4-S2 posterior spinal fusion (PSF); another 12-year-old girl underwent T4-S2 PSF; a 13-year-old boy underwent T3-L4 PSF; and a 14-year-old girl was managed nonoperatively because the complex deformity and ankylosed shoulders could not be adequately balanced with surgery. Conclusion: In patients with FOP, surgical intervention can reduce thoracic deformity and improve pulmonary function but carries substantial risks, including heterotopic ossification.

Purpose: To quantify the prevalence of neural axial abnormalities in congenital early-onset scoliosis (C-EOS) patients stratified by age group, correlate prevalence of treatment, and determine if a delay in MRIs affects outcomes. Methods: A multicenter registry with data on 751 C-EOS patients was retrospectively reviewed, of which 659 patients were included. Data included demographics, pre-index major coronal curve, age at first MRI, intraspinal MRI findings, neurosurgical interventions and scoliosis fixation performed, intraoperative and postoperative complications, and unplanned return to the operating room (UPROR) for orthopaedic complications. Patients were divided into 2 cohorts utilizing age 3 as a cutoff. This age cutoff was selected based on an FDA warning of the potential neurocognitive effects of anesthesia used for MRIs in patients younger than 3 years. Spearman Rho correlations, independent t tests, and χ 2 tests were used for statistical analysis. Results: Patients were divided into 2 groups: first MRI younger than or equal to 3 years of age (n=277) and older than 3 years of age (n=382). One hundred thirty-three abnormal MRIs were identified (20%). There was no significant correlation between age at MRI and abnormal intraspinal findings (rs= −0.018, P =0.64). Among patients with abnormal MRIs, no correlation existed between age at MRI and UPROR. In this cohort, 23 neurosurgical procedures were performed and no significant difference was found in UPROR between groups ( P =0.54). There were 3 neurologic complications in the younger than or equal to 3-year group and 0 in the older than 3-year group ( P =0.07). No significant difference was found in mean pre-index major coronal curve ( P =0.25). Conclusions: The prevalence of neural axis abnormalities in C-EOS was 20%. There was no significant correlation between age at first MRI and the chance of an abnormal MRI. There were no significant differences in neurological complications and UPROR between the younger than or equal to 3-year and older than 3-year groups. Thus, in C-EOS, MRI may be cautiously deferred until after the age of 3 in patients with normal neurological examinations and radiological findings.

» Fibrodysplasia ossificans progressiva (FOP), the most severe form of heterotopic ossification (HO) in humans, may lead to severe thoracic deformity (TD) and thoracic insufficiency syndrome (TIS), the most common cause of mortality in individuals with FOP. » In this study, we examine the multiple causes of TD in FOP and propose a dynamic model for the development and evolution of TD that can be used to guide clinical care. This model posits that multiple factors, all originating from the causative gain-of-function mutation in activin receptor A, type 1, lead to TD in FOP. » Factors that lead to TD in FOP include early developmental costovertebral and facet joint arthropathy and joint ankylosis, progressive episodic flare-ups (both trauma induced or spontaneous) and subsequent HO, dysregulated soft tissue sensitivity to mechanical stimuli, growth plate dysregulation, and congenital rib fusions. These factors contribute to TD in FOP through a combination of intra-articular and extra-articular mechanisms, all amplified by growth. » Although FOP is a rare condition, it is illustrative of how a mutation in a critical receptor in the bone morphogenetic protein signaling pathway can cause a litany of musculoskeletal dysfunction that can lead to life-threatening consequences. Clinicians caring for individuals who have FOP must be aware of the occurrence, evolution, and implications of progressive TD and resultant TIS so that appropriate preventive measures such as avoidance of pulmonary infections, incentive spirometry, and diaphragmatic strengthening can be instituted.

AbstractBackgroundAdolescent Idiopathic Scoliosis (AIS) affects 2%–4% of the general pediatric population. While surgical correction remains one of the most common orthopedic procedures performed in pediatrics, limited consensus exists on the perioperative anesthetic management.AimsTo examine the current state of anesthetic management of typical AIS spine fusions at institutions which have a dedicated pediatric orthopedic spine surgeon.MethodsA web‐based survey was sent to all members of the North American Pediatric Spine Anesthesiologists (NAPSA) Collaborative. This group included 34 anesthesiologists at 19 different institutions, each of whom has a Harms Study Group surgeon performing spine fusions at their hospital.ResultsThirty‐one of 34 (91.2%) anesthesiologists completed the survey, with a missing response rate from 0% to 16.1% depending on the question. Most anesthesia practices (77.4%; 95% confidence interval [CI], 67.7–93.4) do not have patients come for a preoperative visit prior to the day of surgery. Intravenous induction was the preferred method (74.2%; 95% CI 61.3–89.9), with the majority utilizing two peripheral IVs (93.5%; 95% CI 90.3–100) and an arterial line (100%; 95% CI 88.8–100). Paralytic administration for intubation and/or exposure was divided (51.6% rocuronium/vecuronium, 45.2% no paralytic, and 3.2% succinylcholine) amongst respondents. While tranexamic acid was consistently utilized for reducing blood loss, dosing regimens varied. When faced with neuromonitoring signal issues, 67.7% employ a formal protocol. Most anesthesiologists (93.5%; 95% CI 78.6–99.2) extubate immediately postoperatively with patients admitted to an inpatient floor bed (77.4%; 95% CI 67.7–93.3).ConclusionMost anesthesiologists (87.1%; 95% CI 80.6–99.9) report the use of some form of an anesthesia‐based protocol for AIS fusions, but our survey results show there is considerable variation in all aspects of perioperative care. Areas of agreement on management comprise the typical vascular access required, utilization of tranexamic acid, immediate extubation, and disposition to a floor bed. By recognizing the diversity of anesthetic care, we can develop areas of research and improve the perioperative management of AIS.

Background: Severe adolescent idiopathic scoliosis (AIS) can be treated with instrumented fusion, but the number of anchors needed for optimal correction is controversial. Methods: We conducted a multicenter, randomized study that included patients undergoing spinal fusion for single thoracic curves between 45° and 65°, the most common form of operatively treated AIS. Of the 211 patients randomized, 108 were assigned to a high-density screw pattern and 103, to a low-density screw pattern. Surgeons were instructed to use ≥1.8 implants per spinal level fused for patients in the high-implant-density group or ≤1.4 implants per spinal level fused for patients in the low-implant-density group. The primary outcome measure was the percent correction of the coronal curve at the 2-year follow-up. The power analysis for this trial required 174 patients to show equivalence, defined as a 95% confidence interval (CI) within a ±10% correction margin with a probability of 90%. Results: In the intention-to-treat analysis, the mean percent correction of the coronal curve was equivalent between the high-density and low-density groups at the 2-year follow-up (67.6% versus 65.7%; difference, −1.9% [95% CI: −6.1%, 2.2%]). In the per-protocol cohorts, the mean percent correction of the coronal curve was also equivalent between the 2 groups at the 2-year follow-up (65.0% versus 66.1%; difference, 1.1% [95% CI: −3.0%, 5.2%]). A total of 6 patients in the low-density group and 5 patients in the high-density group required reoperation (p = 1.0). Conclusions: In the setting of spinal fusion for primary thoracic AIS curves between 45° and 65°, the percent coronal curve correction obtained with use of a low-implant-density construct and that obtained with use of a high-implant-density construct were equivalent. Level of Evidence: Therapeutic Level I . See Instructions for Authors for a complete description of levels of evidence.

Background: Spinal conditions, such as scoliosis and spinal tumors, are prevalent in neurofibromatosis type 1 (NF1). Despite the recognized importance of their early detection and treatment, there remain knowledge gaps in how to approach these manifestations. The purpose of this study was to utilize the experience of a multidisciplinary committee of experts to establish consensus-based best practice guidelines (BPGs) for spinal screening and surveillance, surgical intervention, and medical therapy in pediatric patients with NF1. Methods: Using the results of a prior systematic review, 10 key questions that required further assessment were first identified. A committee of 20 experts across medical specialties was then chosen based on their clinical experience with spinal deformity and tumors in NF1. These were 9 orthopaedic surgeons, 4 neuro-oncologists/oncologists, 3 neurosurgeons, 2 neurologists, 1 pulmonologist, and 1 clinical geneticist. An initial online survey on current practices and opinions was conducted, followed by 2 additional surveys via a formal consensus-based modified Delphi method. The final survey involved voting on agreement or disagreement with 35 recommendations. Items reaching consensus (≥70% agreement or disagreement) were included in the final BPGs. Results: Consensus was reached for 30 total recommendations on the management of spinal deformity and tumors in NF1. These were 11 recommendations on screening and surveillance, 16 on surgical intervention, and 3 on medical therapy. Five recommendations did not achieve consensus and were excluded from the BPGs. Conclusion: We present a set of consensus-based BPGs comprised of 30 recommendations for spinal screening and surveillance, surgical intervention, and medical therapy in pediatric NF1.

Background: Prior “best practice guidelines” (BPG) have identified strategies to reduce the risk of acute deep surgical site infection (SSI), but there still exists large variability in practice. Further, there is still no consensus on which patients are “high risk” for SSI and how SSI should be diagnosed or treated in pediatric spine surgery. We sought to develop an updated, consensus-based BPG informed by available literature and expert opinion on defining high-SSI risk in pediatric spine surgery and on prevention, diagnosis, and treatment of SSI in this high-risk population. Materials and Methods: After a systematic review of the literature, an expert panel of 21 pediatric spine surgeons was selected from the Harms Study Group based on extensive experience in the field of pediatric spine surgery. Using the Delphi process and iterative survey rounds, the expert panel was surveyed for current practices, presented with the systematic review, given the opportunity to voice opinions through a live discussion session and asked to vote regarding preferences privately. Two survey rounds were conducted electronically, after which a live conference was held to present and discuss results. A final electronic survey was then conducted for final voting. Agreement ≥70% was considered consensus. Items near consensus were revised if feasible to achieve consensus in subsequent surveys. Results: Consensus was reached for 17 items for defining high-SSI risk, 17 items for preventing, 6 for diagnosing, and 9 for treating SSI in this high-risk population. After final voting, all 21 experts agreed to the publication and implementation of these items in their practice. Conclusions: We present a set of updated consensus-based BPGs for defining high-risk and preventing, diagnosing, and treating SSI in high-risk pediatric spine surgery. We believe that this BPG can limit variability in practice and decrease the incidence of SSI in pediatric spine surgery. Level of Evidence: Not applicable.

Study Design: Multicenter retrospective study. Background: Recent studies have demonstrated diminishing returns in patients with early onset scoliosis (EOS) undergoing repeated lengthening of growing rods. Little is known about whether this same phenomenon occurs in patients with lax connective tissue disease (CTD). The primary purpose of this study is to investigate whether EOS patients with connective tissue laxity disorders have diminishing returns during growth friendly surgery. Methods: CTD EOS patients below 10 years old, underwent growth friendly spine surgery with distal anchors and at least 1 proximal spine anchor, and had minimum follow-up of 5 years were included in this study. Coronal T1-S1 height at preindex surgery, postindex, and every available lengthening was assessed. Mean coronal height change during early set distractions and late set distractions were calculated for the cohort. To account for varying distraction intervals, we normalized the distractions by the time interval. The outcome parameter was T1-S1 height gain, mm/year. Results: Twenty-one CTD patients were included in this study. Total coronal height (T1-S1) was 26.7MHCcm before index, 32.2 cm at D1-D3, 34.7 cm at D4-D6, and 36.7 cm at D7-L10. There were no significant differences in coronal height gains between early and late distractions (P=0.70). Moreover, when normalized for time, there was no significant difference in net gain per year at different lengthening time points for the CTD group, P=0.59. Conclusion: There is no evidence of diminishing returns in coronal T1-S1 height gain in patients with EOS in the setting of CTD. Level of Evidence: Level III.

Background: Treatment outcomes and risk factors for neurological deficits in pediatric patients with an os odontoideum are unclear. Methods: We reviewed the data for 102 children with os odontoideum who were managed at 11 centers between 2000 and 2016 and had a minimum duration of follow-up of 2 years. Thirty-one children had nonoperative treatment, and 71 underwent instrumented posterior cervical spinal arthrodesis for the treatment of C1-C2 instability. Nonoperative treatment consisted of observation (n = 29) or immobilization with a cervical collar (n = 1) or halo body jacket (n = 1). Surgical treatment consisted of atlantoaxial (n = 50) or occipitocervical (n = 21) arthrodesis. One patient also underwent transoral odontoidectomy. Results: Thirty children (29%) presented with neurological deficits, 28 of whom had radiographic atlantoaxial instability (atlantoaxial distance >5 mm) or limited space (≤13 mm) available for the spinal cord (risk ratio, 7.8 [95% confidence interval, 2.0 to 31] compared with children with no radiographic risk factors). The 27 children without neurological deficits or atlantoaxial instability at presentation underwent nonoperative treatment and remained asymptomatic. Of the initial nonoperative cohort, one child developed atlantoaxial instability, and another had a persistent neurological deficit; both children underwent spinal arthrodesis during the study period. One child with cervical instability declined surgery and remained asymptomatic. Spinal fusion occurred in 68 patients in the surgical group by the end of the study period (mean, 3.7 years; range, 2.0 to 11.8 years). Surgical complications occurred in 21 children, including nonunion in 12, new neurological deficits in 4, cerebrospinal fluid leak in 2, symptomatic instrumentation requiring removal 2, and vertebral artery injury in 1. Nine children underwent revision surgery. In the surgical group, Japanese Orthopaedic Association neurological function scores improved significantly from preoperatively to the latest follow-up for the upper extremities (p = 0.026) and lower extremities (p = 0.007). Conclusions: The risk of developing a neurological deficit was strongly associated with atlantoaxial instability and limited space available for the spinal cord in children with os odontoideum. Nonoperative treatment was safe for asymptomatic patients without atlantoaxial instability. Spinal arthrodesis resolved the neurological deficits of children with symptomatic os odontoideum. Level of Evidence: Therapeutic Level III . See Instructions for Authors for a complete description of levels of evidence.