Definition of Tweener: Consensus Among Experts in Treating Early-onset Scoliosis.

BACKGROUND: The term "Tweener" is colloquially used to refer to early-onset scoliosis (EOS) patients whose age and development make them candidates for multiple surgical options. The purpose of this study was to establish expert consensus on a definition to formally characterize the Tweener population. METHODS: A 3-round survey of surgeons in an international EOS study group was conducted. Surgeons were provided with various patient characteristics and asked if each was part of their definition for Tweener patients. Responses were analyzed for consensus (≥70%), near-consensus (60% to 69%), and no consensus (<60%). RESULTS: Consensus was reached (89% of respondents) for including chronological age in the Tweener definition; 8 to 10 years for females and 9 to 11 years for males. Surgeons agreed for inclusion of Sanders score, particularly Sanders 2 (86.0%). Patients who have reached Sanders 4, postmenarche, or have closed triradiate cartilage should not be considered Tweeners. Bone age range of 8 years and 10 months to 10 years and 10 months for females (12 y for males) could be part of the Tweener definition. CONCLUSIONS: This study suggests that the Tweener definition could be the following: patients with open triradiate cartilage who are not postmenarche and have not reached Sanders 4, and if they have one of the following: Sanders 2 or chronological age 8 to 10 years for females (9 to 11 y for males) or bone age 8 years and 10 months to 10 years and 10 months for females (12 y for males). This definition will allow for more focused and comparative research on this population. LEVEL OF EVIDENCE: Level V-expert opinion.

Image Distortion in Biplanar Slot Scanning: Patient-specific Factors.

BACKGROUND: Error within imaging measurements can be due to processing, magnification, measurement performance, or patient-specific factors. Previous length measurement studies based on radiographs have shown good intraclass correlation coefficients (ICCs) on single images; but have not assessed interimage distortion. In our study, "image distortion in biplanar slot scanning: technology-specific factors" we determined that there is minimal image distortion due to the image acquisition when using biplanar slot scanning. In this study, we aim to determine the role of patient-specific factors in image distortion, specifically evaluating interimage distortion. METHODS: Digital radiographs and biplanar slot scanner images were reviewed in 43 magnetically controlled growing rod (MCGR) patients. Fifty-five postoperative anteroposterior digital radiographs, 184 follow-up biplanar slot-scanner scanner posteroanterior and 76 biplanar slot-scanner scanner laterals were measured by 2 residents and 1 attending. The manufacturer reported average actuator diameter of 9.02 mm was used as our reference width. RESULTS: Overall, within image interobserver ICC were moderate to excellent (0.635 to 0.983), but the interimage ICCs were poor (0.332). Digital radiographs consistently overestimated the MCGR actuator width (mean=9.655) and biplanar slot-scanner scanner images underestimated it (mean=8.935). The measurement range was large with biplanar slot-scanner scanner posteroanterior (up to 15%) and lateral (22%) measurements and with digital radiographs (39%). Patients with abnormal muscle tone had higher degrees of measurement variability. CONCLUSIONS: We found that neither biplanar slot scanning nor digital radiography was precise or accurate. Digital radiographs consistently overestimated MCGR actuator width and biplanar slot scanning underestimated it. The poor ICC's within and between image subtypes and large standard error of measurement reflected a magnitude of distortion that needs to be accounted for when using length measurements clinically. Unlike the clinically insignificant error that we noted in our previous study "image distortion in biplanar slot scanning: technology-specific factors" (0.5% to 1.5% of the measurement), the error noted in this study (0.2% to 38.5% of the measurement) has the potential to be clinically significant. Patients who have abnormal muscle tone had larger measurement errors, likely stemming from motion during the slot scanning process. LEVEL OF EVIDENCE: Level III.

Image Distortion in Biplanar Slot Scanning: Part 2 Technology-specific Factors.

BACKGROUND: Biplanar digital slot scanning technology has become the standard of care in the treatment of scoliosis. Yet, the amount of distortion and reproducibility of this type of imaging modality has yet to be fully investigated. In our paper "Image distortion in biplanar slot scanning: part 1 patient-specific factors" we found that there was potentially clinically impactful interimage distortion. The purpose of this study was to evaluate the degree to which this image distortion was secondary to the image acquisition process. METHODS: Four 25 mm radio-opaque markers were placed at C3, T1, T12, and L5 on a full-length skeleton model. The skeleton was imaged in 10 different positions within the scanner. Five posteroanterior and 5 lateral images were obtained in each position. Two orthopaedic attending physicians and 3 orthopaedic resident physicians measured the markers for a total of 3200 measurements. Intraclass correlation coefficients (ICCs) and 95% confidence intervals were used to examine image distortion. RESULTS: Average marker size was 24.77, with a standard error of measurement of 0.00493. Image distortion and standard error of measurement accounted for ∼0.5% to 1.5% of total the measurement. Overall, there was good reliability and consistency when looking at markers in different views (ICC 0.790), planes, and locations within the image. Horizontal measurements were found to be more consistent and have better reliability (ICC 0.881) than vertical measurements (ICC 0.386). Position within the scanner had minimal impact on the accuracy of the measurements. CONCLUSIONS: This study demonstrates that there is minimal error due to image acquisition and measurement when using a biplanar slot scanner. Biplanar slot scanning technology tended to underestimate the size of the marker; however, the least accurate measurements only erred by 1.5% from the true length. This indicates that unlike traditional radiographs the sources of error in biplanar slot scanning images are not due to parallax and are likely due to patient-specific factors and rather than the technology itself.

The Association Between the Utilization of Traction and Postoperative Complications Following Growing Rod Instrumentation for Early-onset Scoliosis.

BACKGROUND: Preoperative and/or intraoperative traction have been proposed as adjunctive methods to limit complications associated with growth-friendly instrumentation for early-onset scoliosis (EOS). By gradually correcting the deformity before instrumentation, traction can, theoretically, allow for better overall correction without the complications associated with the immediate intraoperative correction. The purpose of this multicenter study was to investigate the association between preoperative/intraoperative traction and complications following growth-friendly instrumentation for EOS. METHODS: Patients with EOS who underwent growth rod instrumentation before 2017 were identified from 2 registries. Patients were divided into 2 groups: preoperative traction group versus no preoperative traction group. A subgroup analysis was done to compare intraoperative traction only versus no traction. Data was collected on any postoperative complication from implantation to up to 2 years postimplantation. RESULTS: Of 381 patients identified, 57 (15%) and 69 (18%) patients received preoperative and intraoperative traction, respectively. After adjusting for etiology and degree of kyphosis, there was no evidence to suggest that preoperative halo traction reduced the risk of any complication following surgical intervention. Although not statistically significant, a subgroup analysis of patients with severe curves demonstrated a trend toward a markedly reduced hardware failure rate in patients undergoing preoperative halo traction [preoperative traction: 1 (3.1%) vs. no preoperative traction: 11 (14.7%), P=0.083]. Nonidiopathic, hyperkyphotic patients treated with intraoperative traction were 61% less likely to experience any postoperative complication (P=0.067) and were 74% (P=0.091) less likely to experience an unplanned return to the operating room when compared with patients treated without traction. CONCLUSIONS: This multicenter study with a large sample size provides the best evidence to date of the association between the use of traction and postoperative complications. Our results justify the need for future Level I studies aimed at characterizing the complete benefit and risk profile for the use of traction in surgical intervention for EOS. LEVEL OF EVIDENCE: Level III.

Use of Magnetic Spinal Growth Rods (MCGR) With and Without Preoperative Halo-gravity Traction (HGT) for the Treatment of Severe Early-onset Scoliosis (EOS).

BACKGROUND: Correction of severe scoliosis through distraction-based techniques poses a challenge. Magnetically controlled growing rod (MCGR) hardware complications are common with a 27.8% to 46.7% revision rate in under 2 years. Loss of correction and diminishing returns are the norm. Treatment of severe scoliosis with halo-gravity traction (HGT) before MCGR has not been previously reported. The purpose of this study was to assess initial correction, maintenance of correction, and complication rate in patients with severe scoliosis treated with and without HGT before MCGR. METHODS: IRB-approved retrospective single site cohort study of a prospectively collected database. Forty-two patients underwent MCGR between 2014 and 2017 at a single site, 12 with prior growing constructs were excluded, 30 patients were included, 12 patients underwent preoperative HGT. Charts were reviewed for demographic, clinical, and radiographic information. RESULTS: The HGT group had larger major curves averaging 90 (69 to 114) degrees versus 77 (56 to 113) degrees in the non-HGT group P=0.018. Percent correction on preoperative flexibility films were 17% versus 40% for those in the HGT versus non-HGT group, P=0.000. An additional 22% correction of the curve magnitude occurred between the flexibility and in-traction films representing 43% of the total correction achieved, P=0.000, was achieved. EBL, and postoperative major curve and major curve correction were not significant. Thirteen percent of patients experienced complications. Average follow-up was 712 versus 561 days in the HGT versus non-HGT groups. CONCLUSIONS: Large, rigid curves can achieve equivalent correction to flexible curves with HGT. Forty-three percent of the total correction achieved occurred during traction. Thirty percent of the total correction occurred at implantation of the MCGR in the HGT group versus 28% in the non-HGT group. At most recent follow-up HGT patients had statistically maintained their major curve correction better than non-HGT patients. LEVEL OF EVIDENCE: Level III-therapeutic study.

New Single-stage Double Osteotomy for Late-presenting Infantile Tibia Vara: A Comprehensive Approach.

BACKGROUND: Successful surgical treatment of late-presenting infantile tibia vara (ITV) patient requires the correction of oblique deformities. The purpose of this study was to report on a new comprehensive approach to correct and prevent recurrence of these deformities with a single procedure. METHODS: Medical records of 23 consecutive children (7 to 18 y) with advanced ITV (29 knees) were retrospectively reviewed after a mean of 7.3 years postoperatively (range, 2 to 22 y). Indications for the corrective surgery were any child 7 year or older with a varus mechanical axis angle ≥10 degrees or a varus anatomic axis angle ≥11 degrees and a medial tibial angle (MTA) slope <60 degrees. The deformities were corrected with a dome-shaped osteotomy proximal to the tibial tubercle with a midline vertical extension to the subchondral region of the joint and a lateral hemi-epiphysiodesis. RESULTS: At latest follow-up, means and medians of each tibial radiographic axis measurement improved significantly from preoperative values (P<0.001): mechanical axis angle from 23 degrees to 4 degrees varus, anatomic axis angle from 25 degrees varus to 1 degree valgus, MTA downward slope from 30 to 78 degrees, posterior MTA from 59 to 80 degrees. In total, 79% and 74% had good to excellent results based on radiographic criteria and clinical questionnaire for satisfaction, pain and function, respectively. Two abnormal medial tibial plateau types were described. CONCLUSIONS: This is the first study to use a single-stage double osteotomy performed proximal to the tibial tubercle for the late-presenting ITV for children 7 years of age or older. In addition to the effective correction of the 4 major tibial deformities, a lateral proximal tibial hemi-epiphysiodesis minimizes recurrence of tibia vara. A contralateral proximal tibial epiphysiodesis is recommended for treated skeletally immature patients with unilateral disease. LEVEL OF EVIDENCE: Therapeutic level IV. See instructions for authors for a complete description of levels of evidence.

Correction of Angular Deformities Due to Focal Fibrocartilaginous Dysplasia Using Guided Growth: A Preliminary Report.

BACKGROUND: Focal fibrocartilaginous dysplasia (FFCD) is a rare benign disorder that may result in tethering of the physis. These most commonly occur around the knee and may result in angular deformities of the involved extremity. To date treatment has ranged from observation, to curettage, to osteotomy. Our goal with this study is to evaluate the efficacy of guided growth in treating patients with angular deformity due to FFCD. METHODS: This is a retrospective review, we included 3 patients with angular deformities due to FFCD who had undergone 8 plate placement. We reviewed their preoperative and postoperative radiographs, assessed their sagittal and coronal balance and number of procedures. RESULTS: Three patients with FFCD of the femur with an average of 14 months underwent guided growth to correct their angular deformity. Once appropriate correction was achieved the hardware was removed. At final follow-up none of the patients required further surgical intervention for their angular deformity nor had they shown any evidence of recurrence. CONCLUSIONS: FFCD is a rare benign disorder, they most commonly affects the proximal tibia and distal femur and can result in significant angular deformities. Our review of the literature found all of the cases involving the femur progressed to the point where they needed surgical intervention. This ranged from curettage to osteotomy. In this case series we present 3 cases of FFCD of the distal femur that were treated minimally invasively with guided growth. LEVEL OF EVIDENCE: Level 4.

Juvenile Dermatomyositis: A Case of Calcinosis Cutis of the Elbow and Review of the Literature.

Juvenile dermatomyositis is a rare, chronic autoimmune disorder commonly associated with calcinosis cutis. Although great advances have been made in the treatment of juvenile dermatomyositis, little progress has been made in the treatment of calcinosis cutis. It remains resistant to medical treatment and surgical intervention has long been avoided due to early reports of poor wound healing and sinus track formation associated with the surgical excision of calcinosis cutis. The literature on management of calcinosis cutis is sparse and the aim of this paper is to review the literature regarding treatment options for calcinosis cutis and present a case with a large mass involving the elbow that was successfully treated with surgical excision and local fasciocutaneous flap.

Pre-op considerations in neuromuscular scoliosis deformity surgery: proceedings of the half day course at the 58th annual meeting of the Scoliosis Research Society.

Scoliosis is a common complication of neuromuscular disorders. These patients are frequently recalcitrant to nonoperative treatment. When treated surgically, they have the highest risk of complications of all forms of scoliosis. While recent studies have shown an improvement in the rate of complications, they still remain high ranging from 6.3 to 75% depending upon the underlying etiology and the treatment center (Mohamad et al. in J Pediatr Orthop 27:392-397, 2007; McElroy et al. in Spine, 2012; Toll et al. in J Neurosurg Pediatr 22:207-213, 2018; Cognetti et al. in Neurosurg Focus 43:E10, 2017). For those patients who are able to recover from the perioperative period without major complications, several recent studies have shown decreased long-term mortality and improved health-related quality of life in neuromuscular patients who have undergone spine fusion (Bohtz et al. in J Pediatr Orthop 31:668-673, 2011; Ahonen et al. in Neurology 101:e1787-e1792, 2023; Jain et al. in JBJS 98:1821-1828, 2016). It is critically important to optimize patients preoperatively to minimize the risk of post-operative complications and maximize long-term outcomes. In order to do so, one must familiarize themselves with the common complications and their treatment. The most common complications are pulmonary in nature. With reported rates as high as 23-29%, pre-operative optimization should be employed for these patients to minimize the risk of post-operative complications (Sharma et al. in Eur Spine J 22:1230-1249, 2013; Rumalla et al. in J Neurosurg Spine 25:500-508, 2016). The next most common cause of complications are implant related, with 13-23% of patients experiencing an implant-related complication that may require a second procedure (Toll et al. in J Neurosurg Pediatr 22:207-213, 2018; Sharma et al. in Eur Spine J 22:1230-1249, 2013) Therefore optimization of bone quality prior to surgical intervention is important to help minimize the risk of instrumentation failure. Optimization of muscle tone and spasticity may help to decrease the risk of instrumentation complications, but may also contribute to the progression of scoliosis. While only 3% of patients have neurologic complication, significant equipoise remains regarding whether or not patients should undergo prophylactic detethering procedures to minimize those risks (Sharma et al. in Eur Spine J 22:1230-1249, 2013). Although only 1.8% of complications are classified as cardiac related, they can be among the most devastating (Rumalla et al. in J Neurosurg Spine 25:500-508, 2016). Simply understanding the underlying etiology and the potential risks associated with each condition (i.e., conduction abnormalities in a patient with Rett syndrome or cardiomyopathies patients with muscular dystrophy) can be lifesaving. The following article is a summation of the half day course on neuromuscular scoliosis from the 58th annual SRS annual meeting, summarizing the recommendations from some of the world's experts on medical considerations in surgical treatment of neuromuscular scoliosis.

The Fate of The Broken Tether: How Do Curves Treated with Vertebral Body Tethering Behave After Tether Breakage?

STUDY DESIGN: Retrospective, Multicenter. OBJECTIVE: Assess curve progression and occurrence of revision surgery following tether breakage after vertebral body tethering (VBT). SUMMARY OF BACKGROUND DATA: Tether breakage after VBT is common with rates up to 50% reported. In these cases, it remains unknown whether the curve will progress or remain stable. METHODS: Adolescent and juvenile idiopathic scoliosis patients in a multicenter registry with ≥2 year-follow-up after VBT were reviewed. Broken tethers were listed as postoperative complications and identified by increased screw divergence of >5° on serial radiographs. Revision procedures and curve magnitude at subsequent visits were recorded. RESULTS: Of 186 patients who qualified for inclusion, 84 (45.2%) patients with tether breakage were identified with a mean age at VBT of 12.4±1.4 years and mean curve magnitude at index procedure of 51.8°±8.1°. Tether breakage occurred at a mean of 30.3±11.8 months and mean curve of 33.9°±13.2°. Twelve patients (12/84, 14.5%) underwent 13 revision procedures after VBT breakage, including 6 tether revisions and 7 conversions to fusion. All tether revisions occurred within 5 months of breakage identification. No patients with curves <35° after breakage underwent revision. Revision rate was greatest in skeletally immature (Risser 0-3) patients with curves ≥35° at time of breakage (Risser 0-3: 9/17, 53% vs. Risser 4-5: 3/23, 13%, P=0.01).Curves increased by 3.1° and 3.7° in the first and second year, respectively. By two years, 15/30 (50%) progressed >5° and 8/30 (26.7%) progressed greater than 10°. Overall, 66.7% (40/60) reached a curve magnitude >35° at their latest follow-up, and 14/60 (23.3%) reached a curve magnitude greater than 45°. Skeletal maturity did not affect curve progression after tether breakage (P>0.26), but time to rupture did (P=0.048). CONCLUSION: While skeletal immaturity and curve magnitude were not independently associated with curve progression, skeletally immature patients with curves ≥35° at time of rupture are most likely to undergo additional surgery. Most patients can expect progression at least 5° in the first two years after tether breakage, though longer-term behavior remains unknown. LEVEL OF EVIDENCE: III.

To tether or fuse? Significant equipoise remains in treatment recommendations for idiopathic scoliosis.

PURPOSE: Vertebral body tethering (VBT) continues to grow in interest from both a patient and surgeon perspective for the treatment of scoliosis. However, the data are limited when it comes to surgeon selection of both procedure type and instrumented levels. This study sought to assess surgeon variability in treatment recommendation and level selection for VBT versus posterior spinal fusion (PSF) for the management of scoliosis. METHODS: Surgeon members of the Pediatric Spine Study Group and Harms Study Group were queried for treatment recommendations and proposed upper instrumented vertebra (UIV) and lower instrumented vertebra (LIV) selection for PSF and VBT based on 17 detailed clinical vignettes. Responses were subdivided in each clinical vignette according to surgeon experience and treatment recommendations with assessment of intra-rater reliability. Binomial distribution tests were used to establish equipoise, selecting p < 0.10 to indicate the presence of a treatment choice with consensus set > 70% agreement. For treatment choice, responses were assessed first for consensus on the decision to proceed with PSF or VBT. RESULTS: Thirty-five surgeons with varied experience completed the survey with 26 surgeons (74%) completing the second follow-up survey. Overall, VBT was the recommended treatment by 47% of surgeons, ranging by clinical vignette. Consensus in treatment recommendation was present for 6 clinical vignettes including 3 for VBT and 3 for PSF, with equipoise present for the remaining 11. Of the 17 vignettes, 12 demonstrated moderate intra-observer reliability including the 3 consensus vignettes for VBT. Sanders stage ≤ 3 and smaller curve magnitude were related with VBT recommendation but neither age nor curve flexibility significantly influenced the decision to recommend VBT. Surgeons with high VBT volume, ≥ 11 VBT cases/year, were more likely to recommend VBT than those with low volumes (0-10 cases per year (p < 0.0001)). High VBT volume surgeons demonstrated consensus in VBT recommendation for Lenke 5/6 curves (75% mean recommendation). High VBT volume surgeons had a significantly higher VBT recommendation rate for Lenke 1A, 2A curves (71.8% vs 48.0%, p = 0.012), and Lenke 3 curves (62% vs 26.9%, p = 0.023). Equipoise was present for all vignettes in low volume surgeons. In addition, high VBT volume surgeons trended toward including more instrumented levels than low VBT volume surgeons (7.17 vs 6.69 levels). CONCLUSION: Significant equipoise is present among pediatric spine surgeons for treatment recommendations regarding VBT and PSF. Surgeon-, patient-, and curve-specific variables were identified to influence treatment recommendations, including surgeon experience, curve subtype, deformity magnitude, and skeletal maturity. This study highlights the need for continued research in identifying the optimal indications for VBT and PSF in the treatment of pediatric spinal deformity.

Contraindications to magnetically controlled growing rods: consensus among experts in treating early onset scoliosis.

PURPOSE: The purpose of this study was to describe contraindications to the magnetically controlled growing rod (MCGR) in patients with early onset scoliosis (EOS) by establishing consensus amongst expert surgeons who treat these patients frequently. METHODS: Nine pediatric spine surgeons from an international EOS study group participated in semi-structured interviews via email to identify factors that influence decision making in the use of MCGR. A 39-question survey was then developed to specify these factors as contraindications for MCGR-these included patient age and size, etiology, medical comorbidities, coronal and sagittal curve profiles, and skin and soft tissue characteristics. Pediatric spine surgeons from the EOS international study group were invited to complete the survey. A second 29-item survey was created to determine details and clarify results from the first survey. Responses were analyzed for consensus (> 70%), near consensus (60-69%), and no consensus/variability (< 60%) for MCGR contraindication. RESULTS: 56 surgeons of 173 invited (32%) completed the first survey, and 64 (37%) completed the second survey. Responders had a mean of over 15 years in practice (range 1-45) with over 6 years of experience with using MCGR (range 2-12). 71.4% of respondents agreed that patient size characteristics should be considered as contraindications, including BMI (81.3%) and spinal height (84.4%), although a specific BMI range or a specific minimum spinal height were not agreed upon. Among surgeons who agreed that skin and soft tissue problems were contraindications (78.6%), insufficient soft tissue (98%) and skin (89%) to cover MCGR were specified. Among surgeons who reported curve stiffness as a contraindication (85.9%), there was agreement that this curve stiffness should be defined by clinical evaluation (78.2%) and by traction films (72.3%). Among surgeons who reported sagittal curve characteristics as contraindications, hyperkyphosis (95.3%) and sagittal curve apex above T3 (70%) were specified. Surgeons who indicated the need for repetitive MRI as a contraindication (79.7%) agreed that image quality (72.9%) and not patient safety (13.6%) was the concern. In the entire cohort, consensus was not achieved on the following factors: patient age (57.4%), medical comorbidities (46.4%), etiology (53.6%), and coronal curve characteristics (58.9%). CONCLUSION: Surgeon consensus suggests that MCGR should be avoided in patients who have insufficient spinal height to accommodate the MCGR, have potential skin and soft tissue inadequacy, have too stiff a spinal curve, have too much kyphosis, and require repetitive MRI, particularly of the spine. Future data-driven studies using this framework are warranted to generate more specific criteria (e.g. specific degrees of kyphosis) to facilitate clinical decision making for EOS patients. LEVEL OF EVIDENCE: Level V-expert opinion.