Comparison of Distal Spine Anchors and Distal Pelvic Anchors in Children With Hypotonic Neuromuscular Scoliosis Treated With Growth-friendly Instrumentation.

BACKGROUND: Lower preoperative pelvic obliquity (PO) and L5 tilt have been associated with good radiographic outcomes when the fusion ended short of the pelvis in children with neuromuscular scoliosis (NMS). Our purpose was to identify indications to exclude the pelvis in children with hypotonic NMS treated with growth-friendly instrumentation. METHODS: This was a multicenter retrospective review. Children with spinal muscular atrophy and muscular dystrophy treated with dual traditional growing rod, magnetically controlled growing rod, or vertical expandable prosthetic titanium rib with minimum 2-year follow-up after the index surgery were identified. RESULTS: A total of 125 patients met the inclusion criteria. Thirty-eight patients had distal spine anchors (DSAs) and 87 patients had distal pelvic anchors (DPAs) placed at the index surgery. Demographics and length of follow-up were similar between the groups but there was a greater percentage of DPA patients who were nonambulatory [79 patients (91%) vs. 18 patients (47%), P <0.0001]. Preindex radiographic measures were similar except the DSA patients had a lower PO (11 vs. 19 degrees, P =0.0001) and L5 tilt (8 vs. 12 degrees, P =0.001). Postindex and most recent radiographic data were comparable between the groups. There was no difference in the complication and unplanned returns to the operating room rates.Subanalysis of the DSA group based on ambulatory status showed similar radiographic measures except the ambulatory patients had a lower PO at all time points (preindex: 5 vs. 16 degrees, P =0.011; postindex: 6 vs. 10 degrees, P =0.045; most recent follow-up: 5 vs. 14 degrees, P =0.028). Only 1 ambulatory DSA patient had a PO ≥10 degrees at most recent follow-up compared with 6 nonambulatory DSA patients. Three (8%) DSA patients, all nonambulatory, underwent extension of their instrumentation to the pelvis. CONCLUSIONS: Pelvic fixation should be strongly considered in nonambulatory children with hypotonic NMS treated with growth-friendly instrumentation. At intermediate-term follow-up, revision surgery to include the pelvis was rare but DSAs do not seem effective at maintaining control of PO in nonambulatory patients. DSA and DPA were equally effective at maintaining major curve control, and complication and unplanned returns to the operating room rates were similar. LEVEL OF EVIDENCE: Level III-therapeutic.

A Comparative Analysis of Revision Surgery Before or After 2 Years After Graduation From Growth-friendly Surgery for Early Onset Scoliosis.

INTRODUCTION: After discontinuation of growth-friendly (GF) surgery for early onset scoliosis, patients are termed graduates: they undergo a spinal fusion, are observed after final lengthening with GF implant maintenance, or are observed after GF implant removal. The purpose of this study was to compare the rates of and reasons for revision surgery in two cohorts of GF graduates: before or after 2 years of follow-up from graduation. METHODS: A pediatric spine registry was queried for patients who underwent GF spine surgery with a minimum of 2 years of follow-ups after graduation by clinical and/or radiographic evidence. Scoliosis etiology, graduation strategy, number of, and reasons for revision surgery were queried. RESULTS: There were 834 patients with a minimum of 2-year follow-up after graduation who were analyzed. There were 241 (29%) congenital, 271 (33%) neuromuscular, 168 (20%) syndromic, and 154 (18%) idiopathic. 803 (96%) had traditional growing rod/vertical expandable titanium rib as their GF construct and 31 (4%) had magnetically controlled growing rod. Five hundred ninety-six patients (71%) underwent spinal fusion at graduation, 208 (25%) had GF implants retained, and 30 (4%) had GF implants removed.In the entire cohort, there were 108/834 (13%) patients who underwent revision surgery. Of the revisions, 71/108 (66%) occurred as acute revisions (ARs) between 0 and 2 years from graduation (mean 0.6 y), and the most common AR indication was infection (26/71, 37%). The remaining 37/108 (34%) patients underwent delayed revision (DR) surgery >2 years (mean 3.8 y) from graduation, and the most common DR indication was implant issues (17/37, 46%).Graduation strategy affected revision rates. Of the 596 patients with spinal fusion as a graduation strategy, 98/596 (16%) underwent revision, compared with only 8/208 (4%) patients who had their GF implants retained, and 2/30 (7%) that had their GF implants removed ( P ≤ 0.001).A significantly higher percentage of the ARs had a spinal fusion as the graduation strategy (68/71, 96%) compared with 30/37 DRs, (81%, P = 0.015). In addition, the 71 patients who underwent AR undergo more revision surgeries (mean: 2, range: 1 to 7) than 37 patients who underwent DR (mean: 1, range: 1 to 2) ( P = 0.001). CONCLUSION: In this largest reported series of GF graduates to date, the overall risk of revision was 13%. Patients who undergo a revision at any time, as well as ARs in particular, are more likely to have a spinal fusion as their graduation strategy. Patients who underwent AR, on average, undergo more revision surgeries than patients who underwent DR. LEVEL OF EVIDENCE: Level III, comparative.

No Difference in the Rates of Unplanned Return to the Operating Room Between Magnetically Controlled Growing Rods and Traditional Growth Friendly Surgery for Children With Cerebral Palsy.

BACKGROUND: Early-onset scoliosis (EOS) is common in children with cerebral palsy (CP). The effectiveness of magnetically controlled growing rods (MCGR) and the risk for unplanned return to the operating room (UPROR) remain to be studied in this patient population. The primary outcome of this study was to examine the frequency of UPROR between MCGRs as compared with traditional growth friendly (TGF) surgeries for children with EOS secondary to CP. METHODS: Patients with EOS secondary to CP were prospectively identified from an international database, with data retrospectively analyzed. Scoliosis, kyphosis, T1-S1, and T1-T12 height were measured preoperation, immediate postoperation, and at minimum 2-year follow-up. The risk and etiology of UPRORs were compared between MCGR and TGF. RESULTS: Of the 120 patients that met inclusion criteria, 86 received TGF (age 7.5±0. 1.8 y; mean follow-up 7.0±2.9 y) and 34 received MCGR (age 7.1±2.2 y, mean follow-up 2.8±0.0.5 y). Compared with TGF, MCGR resulted in significant improvements in maintenance of scoliosis (P=0.007). At final follow-up, UPRORs were 8 of 34 patients (24%) for MCGR and 37 of 86 patients (43%) for TGF (P=0.05). To minimize the influence of follow-up period, UPRORs within the first 2 years postoperation were evaluated: MCGR (7 of 34 patients, 21%) versus TGF (20 of 86 patients, 23%; P=0.75). Within the first 2 years, etiology of UPROR as a percentage of all patients per group were deep infection (13% TGF, 6% MCGR), implant failure/migration (12% TGF, 9% MCGR), dehiscence (4% TGF, 3% MCGR), and superficial infection (4% TGF, 3% MCGR). The most common etiology of UPROR for TGF was deep infection and for MCGR was implant failure/migration. CONCLUSION: For patients with EOS secondary to CP, there was no difference in the risk of UPROR within the first 2 years postoperatively whether treated with TGF surgery or with MCGRs (23% TGF, 21% MCGR). LEVEL OF EVIDENCE: Level III-retrospective cohort, therapeutic study.

The Impact of Unplanned Return to the Operating Room on Health-related Quality of Life at the End of Growth-friendly Surgical Treatment for Early-onset Scoliosis.

BACKGROUND: Limiting complications, especially unplanned return to the operating room (UPROR), is a major focus in the surgical management of early-onset scoliosis (EOS). Although UPROR remains common in this population, its effect on long-term health-related quality of life (HRQoL) remains unclear. The purpose of this study was to investigate the association between UPROR and end-of-treatment HRQoL in EOS patients treated with growth-friendly instrumentation. METHODS: Patients with EOS who underwent growth-friendly instrumentation at age less than 10 years from 1993 to 2018, and completed treatment, were identified in a multicenter EOS registry. UPROR events were recorded, and end-of-treatment (defined as skeletal maturity and/or definitive spinal fusion) HRQoL was assessed via the 24-item Early-Onset Scoliosis Questionnaire (EOSQ-24). RESULTS: A total of 825 patients were identified, and 325 patients (age at surgery: 6.4 y, follow-up: 8.1 y) had end-of-treatment HRQoL data necessary for our investigation. Overall, 129/325 (39.7%) patients experienced 264 UPROR events; the majority (54.2%) were implant-related. Aside from age and etiology, no other variables were determined to be confounders or effect modifiers. Congenital patients with UPROR had worse pain/discomfort by 10.4 points (P=0.057) and worse pulmonary function by 7.8 points (P=0.102) compared with non-UPROR patients adjusting for age. Neuromuscular patients with UPROR had worse pulmonary function by 10.1 points compared with non-UPROR patients adjusting for age (P=0.037). Idiopathic and syndromic patients with UPROR reported consistently worse domain scores than their non-UPROR counterparts, but smaller (<5-point) differences were seen. CONCLUSIONS: UPROR during growth-friendly surgical treatment for EOS is associated with worse HRQoL in all patients, but particularly in those with neuromuscular or congenital etiologies. Ongoing efforts to avoid UPROR are critical. LEVEL OF EVIDENCE: Level II. This is a multicenter retrospective cohort study investigating the effect of UPROR on HRQoL (prognostic study).

Mortality in Early-Onset Scoliosis During the Growth-friendly Surgery Era.

INTRODUCTION: Early-onset scoliosis (EOS) is a spinal deformity that occurs in patients 9 years of age or younger. Severe deformity may result in thoracic insufficiency, respiratory failure, and premature death. The purpose of this study is to describe the modern-day natural history of mortality in patients with EOS. METHODS: The multicenter Pediatric Spine Study Group database was queried for all patients with EOS who are deceased, without exclusion. Demographics, underlying diagnoses, EOS etiology, operative and nonoperative treatments or observation, complications, and date of death were retrieved. Descriptive statistics and survival analysis with Kaplan-Meier curves were performed. RESULTS: There were 130/8009 patients identified as deceased for a registry mortality rate of 16 per 1000 patients. The mean age at death was 10.6 years (range: 1.0 to 30.2 y) and the most common EOS etiology was neuromuscular (73/130, 56.2%; P<0.001). Deceased patients were more likely be treated operatively than nonoperatively or observed (P<0.001). The mean age of death for patients treated operatively (12.3 y) was older than those treated nonoperatively (7.0 y) or observed (6.3 y) (P<0.001) despite a larger deformity and similar index visit body mass index and ventilation requirements. Kaplan-Meier analysis confirmed an increased survival time in patients with a history of any spine operation compared with patients without a history of spine operation (P<0.0001). Operatively treated patients experienced a median of 3.0 complications from diagnosis to death. Overall, cardiopulmonary related complications were the most common (129/271, 47.6%; P<0.001), followed by implant-related (57/271, 21.0%) and wound-related (26/271, 9.6%). The primary cause of death was identified for 78/130 (60.0%) patients, of which 57/78 (73.1%) were cardiopulmonary related. CONCLUSIONS: This study represents the largest collection of EOS mortality to date, providing surgeons with a modern-day examination of the effects of surgical intervention to better council patients and families. Both fatal and nonfatal complications in children with EOS are most likely to involve the cardiopulmonary system. LEVEL OF EVIDENCE: Level IV-therapeutic.

Impact of growth friendly interventions on spine and pulmonary outcomes of patients with spinal muscular atrophy.

PURPOSE: Patients with spinal muscular atrophy (SMA) are often treated with growth friendly devices such as vertical expandable prosthetic titanium rib(VEPTR) and magnetically controlled growing rods(MCGR) to correct spinal deformity and improve pulmonary function. There is limited data on this topic, and the purpose of this study was to assess the effect of these constructs and the addition of chest wall support (CWS) on spinal deformity, thorax morphology and pulmonary outcomes. METHODS: This is a retrospective analysis of prospectively collected data. We included patients with chest wall deformity and scoliosis secondary to SMA who were treated with growth friendly interventions and had two-year follow-up. Descriptive statistics and univariate analyses were performed. RESULTS: This study included 66 patients (25% MCGR, 73% VEPTR, 2% unknown). Approximately 23% of constructs included CWS. The average Cobb angle improved from 67° (SD: 27°) to 50° (SD: 26°) at 2 years in patients with CWS (p = 0.02), and from 59° (SD: 20°) to 46° (SD: 15°) at 2 years in patients without CWS (p < 0.01). Hemithorax height improved in patients treated with and without CWS (p = 0.01), but hemithorax width only improved in patients with CWS (p = 0.01). One patient with CWS and two patients without CWS required additional respiratory support at 2 years. The rates of postoperative complications were not significantly different in patients treated with and without CWS (p = 0.31). CONCLUSIONS: Growth friendly constructs improve spinal deformity and may be effective in altering the progression toward respiratory failure in patients with SMA. Patients treated with CWS have significant improvements in thorax morphology compared to patients without CWS.

Growth-friendly Spinal Instrumentation in Marfan Syndrome Achieves Sustained Gains in Thoracic Height Amidst High Rates of Implant Failure.

BACKGROUND: There are few reports on the surgical management of early-onset scoliosis (EOS) associated with Marfan syndrome (MFS). Affected patients tend to have more rapid curve progression than those with idiopathic EOS, and their course is further complicated by medical comorbidities. As surgical techniques and implants for growing spines become more widely applied, this study seeks to better delineate the safety and efficacy of growth-friendly spinal instrumentation in treating this population. METHODS: A prospective registry of children treated for EOS was queried for MFS patients treated between 1996 and 2016. Forty-two patients underwent rib-based or spine-based growing instrumentation and were assessed on preoperative, surgical, and postoperative clinical and radiographic parameters including complications and reoperations. Subgroup analysis was performed based on spine-based versus rib-based fixation. RESULTS: Patients underwent their index surgery at a mean age of 5.5 years, when the major coronal curve and kyphosis measured 77 and 50 degrees, respectively. Over half were treated with traditional growing rods. Patients underwent 7.2 total surgical procedures-4.7 lengthening and 1.9 revision surgeries not including conversion to fusion-over a follow-up of 6.5 (±4.1) years. Radiographic correction was greatest at index surgery but maintained over time, with a final thoracic height measuring 23.8 cm. Patients experienced a mean of 2.6 complications over the course of the study period; however, a small group of 6 patients experienced ≥6 complications while over half of patients experienced 0 or 1. Implant failures represented 42% of all complications with infection and pulmonary complications following. CONCLUSIONS: This is the largest report on patients with EOS and MFS. All subtypes of growth-friendly constructs reduced curve progression in this cohort, but complications and reoperations were nearly universal; patients were particularly plagued by implant failure and migration. Further collaborations are needed to enhance understanding of optimal timing and fixation constructs for those with MFS and other connective tissue diseases.

Management of Early-Onset Scoliosis-From Mehta Casts to Magnetically Expandable Rods: State of the Art in 2019.

Early-onset scoliosis (EOS) encompasses a wide variety of challenging to treat spinal deformities occurring in children before 10 years of age. The Classification of Early-Onset Scoliosis (C-EOS) has emerged as a useful classification for both clinical and research purposes, as have similar classifications of surgery and complications in the EOS population. Approaches to both nonsurgical and surgical management of EOS have changed dramatically in recent years. There has been a resurgence of interest in nonsurgical management of EOS following several reports of success with serial Mehta cast treatment. Distraction-based surgical approaches, whether rib- or spine-based, remain the mainstay of surgical treatment. The introduction and widespread adoption of magnetically controlled growing rods (MCGR) has altered the need for repeat surgeries for lengthening in distraction based surgery. However, it remains unclear whether overall complication and unplanned revision surgery rates will be improved over historical traditional growing rods or rib-based distraction. Conversion of growth-friendly instrumentation to a final fusion remains a challenging procedure, with high rates of complications and revision surgeries.

Minimum 5-Year Follow-up on Graduates of Growing Spine Surgery for Early Onset Scoliosis.

INTRODUCTION: After discontinuation of growth friendly (GF) surgery for early onset scoliosis, patients undergo spinal fusion or continued observation. This last planned treatment is colloquially called "definitive" treatment, conferring these patients as "graduates" of a growing program. The 5-year radiographic and clinical outcomes of this cohort are unknown. METHODS: An international pediatric spine database was queried for patients from a GF program (spine or rib-based) with minimum 5-year follow-up from last planned surgery (GF or spinal fusion). Radiographs and charts were reviewed for main coronal curve angle and maximum kyphosis as well as occurrence of secondary surgery. RESULTS: Of 580 graduates, 170 (29%) had minimum 5-year follow-up (37% male). Scoliosis etiology was congenital in 41 (24%), idiopathic 36 (21%), neuromuscular 51 (30%), and syndromic 42 (25%). Index surgery consisted of spine-based growing rods in 122 (71%) and rib-based distraction in 48 (29%). Mean age at index surgery was 6.8 years, and patients underwent an average of 5.4 lengthenings over an average of 4.9 years (range, 6 mo to 11 y). Last planned treatment was at an average age of 11.8 years (range, 7 to 17 years). Last planned treatment consisted of spinal fusion in 114 patients, 47 had growing implants maintained, 9 had implants removed. Average follow-up was 7.3 years (range, 5 to 13 y).When compared from postdefinitive treatment to 2-year follow-up, there was noted progression of the coronal curve angle (46±19 to 51±21 degrees, P=0.046) and kyphosis (48±20 to 57±25 degrees, P=0.03). However, between 2 and 5 years, no further progression occurred in the coronal (51±21 to 53±21 degrees, P=0.26) or sagittal (57±25 to 54±28 degrees, P=0.93) planes. When stratified based on etiology, there was no significant coronal curve progression between 2- and 5-year follow-up. When comparing spinal fusion patients to those who had maintenance of their growing construct, there was also no significant curve progression.Thirty-seven (21%) underwent at least 1 (average, 1.7; range, 1 to 7) revision surgery following graduation, and 15 of 37 (41%) underwent 2 or more revision surgeries. Reason for revision was implant revision (either GF or spinal fusion) in 34 patients, and implant removal in 3. On an average, the first revision was 2.5 years after the definitive treatment plan (range, 0.02 to 7.4 y). In total, 15 of 37 (41%) revisions occurred over 2 years following the final decision for treatment plan, and 7 of 37 (19%) occurred 5 or more years after the definitive treatment.Patients who underwent spinal fusion as a definitive treatment strategy were more likely to undergo revision surgery (27%) than patients who had their GF implants maintained (11%) (P=0.04). CONCLUSIONS: Five years following "graduation" from growing surgery for early onset scoliosis, there is progression of curve magnitude in both the coronal and sagittal planes up to 2 years, with no further progression at 5 years. A total of 21% of patients undergo at least 1 revision surgery, and average time to revision surgery is over 2 years from last planned surgery. Risk of revision surgery was higher in patients who underwent a spinal fusion as their definitive treatment strategy. LEVEL EVIDENCE: Level III-retrospective comparative. TYPE OF EVIDENCE: Therapeutic.

Idiopathic Early-onset Scoliosis: Growing Rods Versus Vertically Expandable Prosthetic Titanium Ribs at 5-year Follow-up.

BACKGROUND: Distraction-based techniques allow spinal growth until skeletal maturity while preventing curve progression. METHODS: Two multicenter early-onset scoliosis databases were used to identify patients with idiopathic spine abnormalities treated with traditional growing rods (TGR) or vertically expandable titanium ribs (VEPTR). Patients underwent at least 4 lengthenings and had at least 5-year follow-up. Significance was set at P<0.05. RESULTS: In total, 50 patients treated with TGR and 22 treated with VEPTR were included. Mean (±SD) age at surgery was 5.5 (±2.0) years for the TGR group versus 4.3 (±1.9) years for the VEPTR group (P=0.044); other demographic parameters were similar. VEPTR patients had more procedures (mean 15±4.2) than TGR patients (mean 10±4.0) (P=0.001). Unilateral constructs were present in 18% (4 of 22) of VEPTR and 16% (8 of 50) of TGR patients. Bilateral constructs spanned a mean 2.1 additional surgical levels and exposed patients to 1.6 fewer procedures than unilateral constructs. Curve correction was similar between bilateral and unilateral constructs. TGR patients experienced greater curve correction (50%) than VEPTR patients (27%) (P<0.001) and achieved a greater percentage of thoracic height gain (24%) than VEPTR patients (12%) (P=0.024). At latest follow-up, TGR patients had better maintenance of curve correction, less kyphosis, and 15% greater absolute gain in thoracic height versus VEPTR patients. TGR patients had a lower rate of wound complications (14%) than VEPTR patients (41%) (P=0.011). CONCLUSIONS: In patients with idiopathic early-onset scoliosis, TGRs produced greater initial curve correction, greater thoracic height gains, less kyphosis, and lower incidence of wound complications compared with VEPTR. LEVEL OF EVIDENCE: Level III.

Characterizing Use of Growth-friendly Implants for Early-onset Scoliosis: A 10-Year Update.

BACKGROUND: Growth-friendly treatment of early-onset scoliosis (EOS) has changed with the development and evolution of multiple devices. This study was designed to characterize changes in the use of growth-friendly implants for EOS from 2007 to 2017. METHODS: We queried the Pediatric Spine Study Group database for patients who underwent index surgery with growth-friendly implants from July 2007 to June 2017. In 1298 patients, we assessed causes of EOS; preoperative curve magnitude; age at first surgery; patient sex; construct type; lengthening interval; incidence of "final" fusion for definitive treatment; and age at definitive treatment. α=0.05. RESULTS: From 2007 to 2017, the annual proportion of patients with idiopathic EOS increased from 12% to 33% (R=0.58, P=0.006). Neuromuscular EOS was the most common type at all time points (range, 33% to 44%). By year, mean preoperative curve magnitude ranged from 67 to 77 degrees, with no significant temporal changes. Mean (±SD) age at first surgery increased from 6.1±2.9 years in 2007 to 7.8±2.5 years in 2017 (R=0.78, P<0.001). As a proportion of new implants, magnetically controlled growing rods increased from <5% during the first 2 years to 83% in the last 2 years of the study. Vertically expandable prosthetic titanium ribs decreased from a peak of 48% to 6%; growth-guidance devices decreased from 10% to 3%. No change was seen in mean surgical lengthening intervals (range, 6 to 9 mo) for the 614 patients with recorded lengthenings. Final fusion was performed in 88% of patients who had undergone definitive treatment, occurring at a mean age of 13.4±2.4 years. CONCLUSIONS: From 2007 to 2017, neuromuscular EOS was the most common diagnosis for patients treated with growth-friendly implants. Patient age at first surgery and the use of magnetically controlled growing rods increased during this time. Preoperative curve magnitude, traditional growing rod lengthening intervals, and rates of final fusion did not change. LEVEL OF EVIDENCE: Level II.

Intrawound Vancomycin Powder Associated With Reduced Surgical Site Infection in Rib-based Distraction Surgery.

BACKGROUND: Despite clinical reports of improved pulmonary function and reduced spinal deformity with rib-based distraction surgery in early-onset scoliosis (EOS) patients, infection remains a common complication, reported as high as 32% in some studies. The purpose of this study was to evaluate intrawound vancomycin powder in pediatric patients managed with rib-based distraction for EOS. METHODS: This was a single institution retrospective cohort study of EOS patients treated with rib-based distraction. Patients treated with and without intrawound vancomycin were compared. Patients included were younger than 18 years of age, had undergone placement of a rib-based distraction construct, and had a minimum of 6 months' follow-up. For patients in the vancomycin group, 500 mg of vancomycin powder was placed before wound closure. Complications including infection and revision surgery were recorded. P-values and 95% confidence intervals (CIs) were reported for both unadjusted and adjusted complication rates for prevancomycin and postvancomycin powder. All P-values were calculated at a significance level of 0.05. RESULTS: In total, 118 patients were included, accounting for 1035 procedures in the nonvancomycin control group and 252 procedures in the vancomycin group. Both groups were similar with regard to age at initial implant, sex, diagnosis, ambulatory status, and bowel/bladder incontinence. There were 55 (5.3%; 95% CI, 4.1-7.6) postoperative infections in the control group and 3 (1.2%; 95% CI, 0.3-3.8) in the vancomycin group (P=0.008, unadjusted). After adjusting for surgery type and transfusions, the vancomycin group still had a significantly lower infection rate (1.4%; 95% CI, 0.3-3.7 vs. 5.5%; 95% CI, 3.04-6.5; P=0.022). We were unable to demonstrate a difference between the control (3.5%, 95% CI, 2.4-5.1) and vancomycin (1.8%, 95% CI, 0.5-5.7) groups for deep infection (P=0.27). CONCLUSIONS: Intrawound vancomycin powder significantly reduced the surgical site infection rates following rib-based distraction surgery for EOS. We therefore recommend the use of intrawound vancomycin powder as a standard of care for patients undergoing rib-based distraction surgery. LEVEL OF EVIDENCE: Pre-post intervention, retrospective cohort study-therapeutic level III.

Variation in Adolescent Idiopathic Scoliosis Surgery: Implications for Improving Healthcare Value.

OBJECTIVES: To investigate the variation in care and cost of spinal fusion for adolescent idiopathic scoliosis (AIS), and to identify opportunities for improving healthcare value. STUDY DESIGN: Retrospective cohort study from the Pediatric Health Information Systems database, including children 11-18 years of age with AIS who underwent spinal fusion surgery between 2004 and 2015. Multivariable regression was used to evaluate the relationships between hospital cost, patient outcomes, and resource use. RESULTS: There were 16 992 cases of AIS surgery identified. There was marked variation across hospitals in rates of intensive care unit admission (0.5%-99.2%), blood transfusions (0%-100%), surgical complications (1.8%-32.3%), and total hospital costs ($31 278-$90 379). Hospital cost was 32% higher at hospitals that most frequently admitted patients to the intensive care unit (P = .009), and 8% higher for each additional 25 operative cases per hospital (P = .003). Hospital duration of stay was shorter for patients admitted to hospitals with highest intensive care unit admission rates and higher surgical volumes. There was no association between cost and duration of stay, 30-day readmission, or surgical complications. The largest contribution to hospital charges was supplies (55%). Review of a single hospital's detailed cost accounting system also found supplies to be the greatest single contributor to cost, the majority of which were for spinal implants, accounting for 39% of total hospital costs. CONCLUSIONS: The greatest contribution to AIS surgery cost was supplies, the majority of which is likely attributed to spinal implant costs. Opportunities for improving healthcare value should focus on controlling costs of spinal instrumentation, and improving quality of care with standardized treatment protocols.

Complication Severity Score for Growth-friendly Surgery Has Strong Interrater and Intrarater Agreement.

BACKGROUND: Growth-friendly surgery has high complication rates. The Complication Severity Score for growth-friendly surgery was developed to maintain consistency while reporting complications as part of research in this rapidly evolving field. This study evaluates the interrater and intrarater reliability of this complication classification system. METHODS: After Institutional Review Board approval, complications during treatment for early onset scoliosis were identified from a prospectively collected database. Previous validation studies and a 10-case pilot survey determined that 60 cases were needed to represent a minimum of substantial agreement. In total, 63 of 496 cases were selected randomly to evenly represent each severity classification. The cases comprised an internet survey for classification sent to faculty and research coordinators involved in early onset scoliosis research, 3 weeks apart, with questions shuffled between iterations. Fleiss Kappa and Cohen Kappa were used to assess interrater and intrarater agreement, respectively. RESULTS: A total of 20 participants, 12 faculty and 8 research assistants, completed the survey twice. The overall Fleiss Kappa coefficient for interrater agreement from the second round of the survey was 0.86 (95% confidence interval, 0.86-87), which represents substantial agreement. Reviewers agreed almost perfectly on categorizing complications as Device I (0.85), Disease I (0.91), Disease II (0.94), Device IIB (0.92), and Disease IV (0.98). There was substantial agreement for categorizing Device IIA (0.73) and Device III (0.76) complications. Disease III and Device IV were not evaluated in this survey since none of these occurred in the database. There was almost perfect intrarater agreement among faculty (0.87), research coordinators (0.85), and overall (0.86). CONCLUSIONS: There is strong interrater and intrarater agreement for the published complications classification scheme for growing spine surgery. The complication classification system is a reliable tool for standardizing reports of complications with growth-friendly surgery. Adoption of this classification when reporting on growth-friendly surgery is recommended to allow for comparison of complications between treatment modalities. LEVEL OF EVIDENCE: Level I-diagnostic study.

The Final 24-Item Early Onset Scoliosis Questionnaires (EOSQ-24): Validity, Reliability and Responsiveness.

INTRODUCTION: The goal of early-onset scoliosis (EOS) treatment is to improve health-related quality of life (HRQoL) for patients and to reduce the burden on their parents or caregivers. The purpose of this study is to develop and finalize the 24-item Early-Onset Scoliosis Questionnaire (EOSQ-24), and examine the validity, reliability, and responsiveness of the EOSQ-24 in measuring patients' HRQoL, the burden on their caregivers, and the burden on their caregiver's finances. The study also established aged-matched normative values for the EOSQ-24. METHODS: The EOSQ-24 was administered to caregivers of male and female patients aged 0 to 18 years with EOS. Patients with EOS are diagnosed before 10 years of age. Criterion validity was investigated by measuring agreement between its scores and pulmonary function testing. Construct validity was established by comparing values across different etiology groups using the known-group method, and measuring internal consistency reliability. Content validity was confirmed by reviewing caregiver and health provider ratings for the relativity and clarity of the EOSQ-24 questions. Test-retest reliability was examined through intraclass correlation coefficients. Responsiveness of the EOSQ-24 before and after surgical interventions was also investigated. Age-matched, healthy patients, without spinal deformity, were enrolled to establish normative EOSQ-24 values. RESULTS: The pulmonary function subdomain score in the EOSQ-24 was positively correlated with pulmonary function testing values, establishing criterion validity. The EOSQ-24 scores for neuromuscular patients were significantly decreased compared with idiopathic or congenital/structural patients, demonstrating known-group validity. Internal consistency reliability of patients' HRQoL was excellent (0.92), but Family Burden was questionable (0.64) indicating that Parental Burden and Financial Burden should be in separate domains. All 24 EOSQ items were rated as essential and clear, confirming content validity. All EOSQ-24 domains demonstrated good to excellent agreement (0.68 to 0.98) between test and retest scores. Neuromuscular patients improved their HRQoL postoperatively, whereas idiopathic patients worsened their HRQoL postoperatively, indicating the ability of the instrument to respond to different trajectories of HRQoL according to etiology in patients with EOS. DISCUSSION: The developed and finalized EOSQ-24 is a valid, reliable, and responsive instrument that is able to serve as a patient-reported outcome measure evaluating health status for patients with EOS and burden of their caregivers. This instrument will be able to serve as an outcome measure for future research including clinical trials evaluating the effectiveness of various treatments. In addition, the EOSQ-24 allows assessment of patients' HRQoL, and the burden on their caregivers relative to age-matched healthy peers. LEVEL OF EVIDENCE: Level II-diagnostic study with consecutive patients enrolled in national registries.

What is the Risk of Developing Proximal Junctional Kyphosis During Growth Friendly Treatments for Early-onset Scoliosis?

BACKGROUND: Rib-based and spine-based systems are commonly used distraction-based growth friendly treatments for early-onset scoliosis (EOS). Our primary purpose was to determine the risk of developing postoperative proximal junctional kyphosis (PJK) during distraction-based growth friendly surgery. METHODS: A multicenter, retrospective, radiographic comparison was performed for a group of 40 children with EOS who were treated with posterior distraction-based implants. PJK was defined as proximal junction sagittal angle (PJA)≥10 degrees and PJA at least 10 degrees greater than preoperative. RESULTS: Eight subjects (20%) at immediate postoperative follow-up and 11 subjects (27.5%) at minimum 2-year follow-up had developed PJK. The risk of developing PJK between rib-based and spine-based growing systems was not significantly different at immediate postoperative (17% vs. 25%) or at final (25% vs. 31%) follow-ups.Further analysis combining both treatment groups demonstrated that PJK subjects were significantly older at time of initial surgery (7.1 y PJK vs. 5.0 y no PJK). Radiographic comparisons between PJK versus no PJK: Preoperative scoliosis (69.9 vs. 76.0 degrees), thoracic kyphosis (45.1 vs. 28.7 degrees), lumbar lordosis (53.1 vs. 44.0 degrees), PJA (2.2 vs. 2.8 degrees), sagittal vertical axis (1.5 vs. 2.6 cm), pelvic incidence (52.8 vs. 47.4 degrees), pelvic tilt (14.3 vs. 8.7 degrees), and sacral slope (37.7 vs. 35.9 degrees). At both initial postoperative and at final follow-up visits, a significant difference was found for cervical lordosis 32.2 versus 14.0 degrees and 42.0 versus 16.6 degrees, respectively. Risk ratio for developing PJK at final follow-up was 2.8 for subjects with preoperative thoracic hyperkyphosis and was 3.1 for subjects with high pelvic incidence (P<0.05). CONCLUSIONS: The risk of developing PJK during distraction-based growth friendly treatment for EOS was 20% immediately after implantation and 28% at minimum 2-year follow-up, with no difference observed between rib-based and spine-based treatment groups. As this study identifies a significant risk of developing PJK during the treatment of EOS, it allows clinicians to preoperatively council patients and their families about this possible complication. In addition, several potential risk factors for the development of postoperative PJK were identified, but should be investigated further in future studies. LEVEL OF EVIDENCE: Level III-therapeutic study (retrospective, comparative).

Patients Without Intraoperative Neuromonitoring (IONM) Alerts During VEPTR Implantation Did Not Sustain Neurological Injury During Subsequent Routine Expansions: A Retrospective Multicenter Cohort Study.

BACKGROUND: The purpose of this study was to determine the rate of intraoperative neurological monitoring (IONM) alerts and neurological injury during vertical expandable prosthetic titanium rib (VEPTR) treatment and evaluate the utility of IONM during VEPTR expansion procedures in patients who have not previously had neurological injury or IONM alerts. METHODS: After institutional review board approval, VEPTR procedures and IONM records were reviewed at 17 institutions for patients treated with VEPTR from 2005 to 2011. All consecutive cases in patients with minimum 2-year follow-up were included. Patients with prior history of growing rods or other invasive spine-based surgical treatment were excluded. Surgeries were categorized into implant, revision, expansion, and removal procedures. Cases with IONM alerts or neurological injury had additional detailed review. Descriptive statistics were used for data analysis. RESULTS: In total, 2355 consecutive VEPTR procedures (352 patients) consisting of 299 implant, 377 revision, 1587 expansion, and 92 removal procedures were included. In total, 620 VEPTR procedures had IONM, and 539 of those had IONM records available for review. IONM alerts occurred in 9/539 procedures (1.7%): 3/192 implants (1.6%), 3/58 revisions (5.2%), and 3/258 expansions (1.2%). New neurological injury occurred in 3/2355 procedures (0.1%), 3/352 patients (0.9%). All 3 injuries were in implant procedures, only 1 had an IONM alert. All 3 had upper extremity motor deficits (1 had sensory deficit also). All had full recovery at 17, 30, and 124 days postinjury. One patient without prior neurological injury or IONM alert had an IONM alert during expansion that resolved after an increase in blood pressure. The remaining IONM alerts during expansions were all in children with prior IONM alerts during implant, revision, or exchange procedures. CONCLUSIONS: The highest rate of neurological injury in VEPTR surgery was found for implant procedures. There were no instances of neurological injury during VEPTR expansion, revision, or removal procedures. IONM did not identify new neurological injuries in patients undergoing VEPTR expansion who did not previously have a history of IONM signal change or neurologic injury. LEVEL OF EVIDENCE: Level IV-diagnostic study.

The Classification for Early-onset Scoliosis (C-EOS) Correlates With the Speed of Vertical Expandable Prosthetic Titanium Rib (VEPTR) Proximal Anchor Failure.

BACKGROUND: The Classification for Early-onset Scoliosis (C-EOS) was developed by a consortium of early-onset scoliosis (EOS) surgeons. This study aims to examine if the C-EOS classification correlates with the speed (failure/unit time) of proximal anchor failure in EOS surgery patients. METHODS: A total of 106 EOS patients were retrospectively queried from an EOS database. All patients were treated with vertical expandable prosthetic titanium rib and experienced proximal anchor failure. Patients were classified by the C-EOS, which includes a term for etiology [C: Congenital (54.2%), M: Neuromuscular (32.3%), S: Syndromic (8.3%), I: Idiopathic (5.2%)], major curve angle [1: ≤20 degrees (0%), 2: 21 to 50 degrees (15.6%), 3: 51 to 90 degrees (66.7%), 4: >90 degrees (17.7%)], and kyphosis ["-": ≤20 (13.5%), "N": 21 to 50 (42.7%), "+": >50 (43.8%)]. Outcome was measured by time and number of lengthenings to failure. RESULTS: Analyzing C-EOS classes with >3 subjects, survival analysis demonstrates that the C-EOS discriminates low, medium, and high speed of failure. The low speed of failure group consisted of congenital/51-90/hypokyphosis (C3-) class. The medium-speed group consisted of congenital/51-90/normal and hyperkyphosis (C3N, C3+), and neuromuscular/51-90/hyperkyphosis (M3+) classes. The high-speed group consisted of neuromuscular/51-90/normal kyphosis (M3N), and neuromuscular/>90/normal and hyperkyphosis (M4N, M4+) classes. Significant differences were found in time (P<0.05) and number of expansions (P<0.05) before failure between congenital and neuromuscular classes.As isolated variables, neuromuscular etiology experienced a significantly faster time to failure compared with patients with idiopathic (P<0.001) and congenital (P=0.026) etiology. Patients with a major curve angle >90 degrees demonstrated significantly faster speed of failure compared with patients with major curve angle 21 to 50 degrees (P=0.011). CONCLUSIONS: The ability of the C-EOS to discriminate the speeds of failure of the various classification subgroups supports its validity and demonstrates its potential use in guiding decision making. Further experience with the C-EOS may allow more tailored treatment, and perhaps better outcomes of patients with EOS. LEVEL OF EVIDENCE: Level III.

VEPTR Implantation After Age 3 is Associated With Similar Radiographic Outcomes With Fewer Complications.

BACKGROUND: The purpose of this study was to analyze the risks and benefits of early vertical expandable prosthetic titanium rib (VEPTR) implantation (below 3 y of age) compared with delayed intervention (3 to 6 y of age). Early intervention with milder deformity may make device implantation easier and may facilitate symmetric chest and pulmonary development. However, later intervention may decrease the number of lengthenings required, and implant anchor points and bone quality may be better in older patients. METHODS: A multicenter prospective database of patients treated with the VEPTR device was retrospectively reviewed. A total of 71 patients with minimum 5-year follow-up were included. Thirty-seven patients had VEPTR surgery below 3 years of age (group 1), and 34 patients had surgery between 3 and 6 years of age (group 2). Radiographs from the preoperative, immediate postoperative, and most recent follow-up visits were reviewed to determine coronal plane deformity and change in T1-T12 height over time. Complications were analyzed using a nonparametric mean cumulative function for the number of complications per subject over time. RESULTS: Patients in both groups had similar diagnoses, ASA scores (P=0.22), and number of lengthenings (10±4 in both groups, P=0.40). Preoperative and most recent major Cobb angles were not significantly different between the 2 groups [66±22 and 60±20 degrees (group 1) vs. 63±19 and 57±23 degrees (group 2), respectively] (P=0.38). The change in T1-T12 was significantly correlated with the number of lengthenings (P<0.001); however, there was no difference between age groups (P=0.55). There were 118 complications in 33 subjects in group 1 and there were 69 complications in 28 subjects in group 2. The number of complications per lengthening was significantly different between the 2 age groups (P<0.001). Subjects in group 2 had 41% fewer complications per lengthening compared with subjects in group 1 (P<0.001). CONCLUSIONS: VEPTR treatment resulted in similar deformity control and thoracic growth in both age groups with lower complication rates in the older population. The rate of complications was similar between the 2 groups for the first 2 years postimplantation, but after 2 years, the rate of complications increased over time faster for the younger group compared with the older group. LEVEL OF EVIDENCE: Level III-retrospective chart and radiographic review.

Rib-based Distraction Surgery Maintains Total Spine Growth.

BACKGROUND: For children undergoing treatment of early onset scoliosis (EOS) using spine-based distraction, recently published research would suggest that total spine length (T1-S1) achieved after the initial lengthening procedure decreases with each subsequent lengthening. Our purpose was to evaluate the effect of rib-based distraction on spine growth in children with EOS. METHODS: This was a retrospective multi-center review of 35 patients treated with rib-based distraction (minimum 5 y follow-up). Radiographs were analyzed at initial implantation and just before each subsequent lengthening. The primary outcome was T1-S1 height, which was also analyzed as: Change in T1-S1 height per lengthening procedure, percent of expected age-based T1-S1 growth per lengthening time interval, percent increase in T1-S1 height as compared with postimplantation total spine height, and percent of expected T1-S1 growth based upon patient age at time of lengthening procedure. RESULTS: Thirty-five patients with a mean age of 2.6 years at initial surgery were studied. Diagnoses included congenital (n=18), syndromic (n=7), idiopathic (n=5), and neuromuscular (n=5). Major Cobb angle was 63.5 degrees and kyphosis was 40.5 degree. Four postoperative time periods were compared: L1 (preoperative first lengthening surgery), L2-L5 (preoperative second lengthening to preoperative fifth lengthening), L6-L10 (preoperative sixth lengthening to preoperative 10th lengthening), L11-L15 (preoperative 11th lengthening to preoperative 15th lengthening). Cobb angle stayed relatively constant for each lengthening period while maximum kyphosis increased. Total spine height was 19.9 cm pre-implantation, 22.1 cm postimplantation, and 28.0 cm by the 15th lengthening (P<0.05). Percent expected T1-S1 growth per lengthening was 62% for L2-L5, 95% for L6-L10, and 52% for L11-L15. As compared with postimplantation spine height, over the course of 15 lengthening procedures, a further 27% increase in spine height was observed. When lengthening procedures were performed when children were under age 5 years, 82% of expected growth was observed; between ages 6 and 10 years, 76% of expected growth was observed; and beyond age 10 years, 14% of expected growth was observed. CONCLUSIONS: Patients treated with rib-based distraction surgery had an increase in total spine height from 20 cm preimplantation to 28 cm by the 15th lengthening. They maintained greater than 75% of expected age-matched spine growth until age 10 years and lengthening procedures did not appear to follow a law of diminishing returns. Rib-based distraction is an effective means of maintaining spine growth which is likely beneficial for pulmonary development as compared with the natural history of EOS. LEVEL OF EVIDENCE: Level IV-Therapeutic study, case series.