Vertebral body tethering for adolescent idiopathic scoliosis: a review

PURPOSE

Adolescent Idiopathic Scoliosis (AIS) remains the most common type of pediatric scoliosis, mostly affecting children between ages 10 and 18. Vertebral body tethering (VBT) offers a non-fusion alternative to the gold standard spinal fusion that permits flexibility and some growth within instrumented segments. This article will serve as a comprehensive literature review of the current state-of-the-art of VBT in relation to radiographic and clinical outcomes, complications, and the learning curve associated with the procedure.

METHODS

A systematic literature review was conducted on PubMed, Scopus, and Web of Science from April 2002 to December 2022. Studies were included if they discussed VBT and consisted of clinical studies in which a minimum 2-years follow-up was reported, and series that included anesthetic considerations, learning curve, and early operative morbidity.

RESULTS

Forty-nine studies spanning the period from April 2002 to December 2022 were reviewed.

CONCLUSION

This article illustrates the potential benefits and challenges of the surgical treatment of AIS with VBT and can serve as a basis for the further study and refinement of this technique ideally as a living document that will be updated regularly.

Incidence of Tether Breakage in Anterior Vertebral Body Tethering

BACKGROUND

Thoracic anterior vertebral body tethering (TAVBT) is an emerging treatment for adolescent idiopathic scoliosis. Tether breakage is a known complication of TAVBT with incompletely known incidence. We aim to define the incidence of tether breakage in patients with adolescent idiopathic scoliosis who undergo TAVBT. The incidence of tether breakage in TAVBT is hypothesized to be high and increase with time postoperatively.

METHODS

All patients with right-sided, thoracic curves who underwent TAVBT with at least 2 and up to 3 years of radiographic follow-up were included. Tether breakage between 2 vertebrae was defined a priori as any increase in adjacent screw angle >5 degrees from the minimum over the follow-up period. The presence and timing of tether breakage were noted for each patient. A Kaplan-Meier survival analysis was performed to calculate expected tether breakage up to 36 months. χ 2 analysis was performed to examine the relationship between tether breakage and reoperations. Independent t test was used to compare the average final Cobb angle between cohorts.

RESULTS

In total, 208 patients from 10 centers were included in our review. Radiographically identified tether breakage occurred in 75 patients (36%). The initial break occurred at or beyond 24 months in 66 patients (88%). Kaplan-Meier survival analysis estimated the cumulative rate of expected tether breakage to be 19% at 24 months, increasing to 50% at 36 months. Twenty-one patients (28%) with a radiographically identified tether breakage went on to require reoperation, with 9 patients (12%) requiring conversion to posterior spinal fusion. Patients with a radiographically identified tether breakage went on to require conversion to posterior spinal fusion more often than those patients without identified tether breakage (12% vs. 2%; P =0.004). The average major coronal curve angle at final follow-up was significantly larger for patients with radiographically identified tether breakage than for those without tether breakage (31 deg±12 deg vs. 26 deg±12 deg; P =0.002).

CONCLUSIONS

The incidence of tether breakage in TAVBT is high, and it is expected to occur in 50% of patients by 36 months postoperatively.

LEVEL OF EVIDENCE

Level IV.

Bilateral vertebral body tethering: identifying key factors associated with successful outcomes

PURPOSE

The treatment of operative double major pediatric spinal deformities (e.g., Lenke 3 or 6) with bilateral vertebral body tethering (VBT) can be significantly more challenging when compared to other deformity patterns (e.g., Lenke 1) or treatment with a posterior spinal fusion. We aimed to identify preoperative and perioperative characteristics that were associated with successful postoperative outcomes in patients treated with both a thoracic and thoracolumbar (e.g., bilateral) tether.

METHODS

We retrospectively assessed radiographic and clinical data from patients enrolled in a large multi-center study who had a minimum postoperative follow-up of two years. Standard radiographic parameters were extracted from standing spine and left hand-wrist radiographs at various timepoints. We classified patients based on their preoperative deformity pattern (Primary Thoracic [TP] vs. Primary Thoracolumbar [TLP]) and assessed: (1) deformity balance, (2) tilt of the transitional vertebra, and (3) postoperative success.

RESULTS

We analyzed data from thirty-six patients (TP: 19 and TLP: 17). We observed no relationship between deformity balance at first erect and postoperative success (p = 0.354). Patients with a horizontal transitional vertebra at first erect were significantly (p = 0.001) more likely to exhibit a successful outcome when compared to those who exhibited a tilted transitional vertebra (83% vs. 62%). Patients who had TLP were also more likely to exhibit a successful outcome when compared to patients who exhibited TP (76% vs. 50%).

CONCLUSION

These data indicate that double major deformities can be successfully treated with VBT, particularly for those who exhibit TLP.

Surgical Outcomes of Cerebral Palsy Patients With Scoliosis and Lumbar Hyperlordosis: A Comparative Analysis With 2-year Minimum Follow-up

STUDY DESIGN

Retrospective review of a prospectively collected multicenter database.

OBJECTIVE

To compare outcomes of patients with cerebral palsy (CP) who undergo surgery for scoliosis with normal lordosis (NL) versus hyperlordosis.

SUMMARY OF BACKGROUND DATA

Surgical correction of scoliosis with lumbar hyperlordosis is challenging. Hyperlordosis may confer higher perioperative morbidity, but this is not well understood.

MATERIALS AND METHODS

A multicenter database was queried for CP patients who underwent surgery from 2008 to 2017. The minimum follow-up was 2 years. Two groups were identified: lumbar lordosis <75° (NL) versus ≥ 75° hyperlordosis (HL). Perioperative, radiographic, and clinical outcomes were compared.

RESULTS

Two hundred seventy-five patients were studied: 236 NL and 39 HL (-75 to -125°). The mean age was 14.1 years, and 52.4% were male. Patients with hyperlordosis had less cognitive impairment (76.9% vs. 94.0%, P =0.008) and higher CPCHILD scores (59.4 vs. 51.0, P =0.003). Other demographics were similar between the groups. Patients with hyperlordosis had greater lumbar lordosis (-90.5 vs. -31.5°, P <0.001) and smaller sagittal vertical axis (-4.0 vs. 2.6 cm, P <0.001). Patients with hyperlordosis had greater estimated blood loss (2222.0 vs. 1460.7 mL, P <0.001) but a similar perioperative complication rate (20.5% vs. 22.5%, P =0.787). Significant correction of all radiographic parameters was achieved in both groups. The HL group had postoperative lumbar lordosis of -68.2° and sagittal vertical axis of -1.0 cm. At a 2-year follow-up, patients with hyperlordosis continued to have higher CPCHILD scores and gained the greatest benefit in overall quality of life measures (20.0 vs. 6.1, P =0.008). The reoperation rate was 10.2%: implant failure (3.6%), pseudarthrosis (0.7%), and wound complications (7.3%). There were no differences in the reoperation rate between the groups.

CONCLUSION

Surgical correction of scoliosis with hyperlordosis is associated with greater estimated blood loss but similar radiographic results, perioperative morbidity, and reoperation rate as normal lordosis. Patients with hyperlordosis gained greater overall health benefits. Correction of ≥25% of hyperlordosis seems satisfactory.

LEVEL OF EVIDENCE

3.

Pregnancy and Childbirth After Spinal Fusion for Adolescent Idiopathic Scoliosis

BACKGROUND

Little data exist on pregnancy and childbirth for adolescent idiopathic scoliosis (AIS) patients treated with a spinal fusion. The current literature relies on data from patients treated with spinal fusion techniques and instrumentation, such as Harrington rods, that are no longer in use. The objective of our study is to understand the effects of spinal fusion in adolescence on pregnancy and childbirth.

METHODS

Prospectively collected data of AIS patients undergoing posterior spinal fusion that were enrolled in a multicenter study who have had a pregnancy and childbirth were reviewed. Results were summarized using descriptive statistics and compared with national averages using χ 2 test of independence.

RESULTS

A total of 78 babies were born to 53 AIS patients. As part of their pre-natal care, 24% of patients surveyed reported meeting with an anesthesiologist before delivery. The most common types of delivery were spontaneous vaginal delivery (46%, n=36/78) and planned cesarean section (20%, n=16/78). Compared with the national average, study patients had a higher rate of cesarean delivery ( P =0.021). Of the women who had a spontaneous vaginal birth, 53% had no anesthesia (n=19/36), 19% received intravenous intermittent opioids (n=7/36), and 31% had regional spinal or epidural anesthesia (n=11/36). spontaneous vaginal delivery patients in our study cohort received epidural or spinal anesthesia less frequently than the national average ( P <0.001). Of those (n=26 pregnancies) who did not have regional anesthesia (patients who had no anesthesia or utilized IV intermittent opioids), 19% (n=5 pregnancies) were told by their perinatal providers that it was precluded by previous spine surgery.

CONCLUSION

The majority of AIS patients reported not meeting with an anesthesiologist before giving birth and those who had a planned C-section did so under obstetrician recommendation. The presence of instrumentation after spinal fusion should be avoided with attempted access to the spinal canal but should not dictate a delivery plan. A multidisciplinary team consisting of obstetrician, anesthesiologist, and orthopaedic surgeon can provide the most comprehensive information to empower a patient to make her decisions regarding birth experience anesthesia based on maternal rather than provider preference.

LEVEL OF EVIDENCE

IV.

Evaluating Adult Idiopathic Scoliosis as an Independent Risk Factor for Critical Illness in SARS-CoV-2 Infection

BACKGROUND

Thoracic spinal deformities may reduce chest wall compliance, leading to respiratory complications. The first SARS-CoV-2 (L-variant) strain caused critical respiratory illness, especially in vulnerable patients. This study investigates the association between scoliosis and SARS-CoV-2 (COVID-19) disease course severity.

METHODS

Clinical data of 129 patients treated between March 2020 to June 2021 who received a positive COVID-19 polymerase chain reaction result from Mount Sinai and had a scoliosis ICD-10 code (M41.0-M41.9) was retrospectively analyzed. Degree of coronal plane scoliosis on imaging was confirmed by 2 independent measurers and grouped into no scoliosis (Cobb angle <10°), mild (10°-24°), moderate (25°-39°), and severe (>40°) cohorts. Baseline characteristics were compared, and a multivariable logistic regression controlling for clinically significant comorbidities examined the significance of scoliosis as an independent risk factor for hospitalization, intensive care unit (ICU) admission, acute respiratory distress syndrome (ARDS), mechanical ventilation, and mortality.

RESULTS

The no (n = 42), mild (n = 14), moderate (n = 44), and severe scoliosis (n = 29) cohorts differed significantly only in age (P = 0.026). The percentage of patients hospitalized (P = 0.59), admitted to the ICU (P = 0.33), developing ARDS (P = 0.77), requiring mechanical ventilation (P = 1.0), or who expired (P = 0.77) did not significantly differ between cohorts. The scoliosis cohorts did not have a significantly higher likelihood of hospital admission (mild P = 0.19, moderate P = 0.67, severe P = 0.98), ICU admission (P = 0.97, P = 0.94, P = 0.22), ARDS (P = 0.87, P = 0.74, P = 0.94), mechanical ventilation (P = 0.73, P = 0.69, P = 0.70), or mortality (P = 0.74, P = 0.87, P = 0.66) than the no scoliosis cohort.

CONCLUSIONS

Scoliosis was not an independent risk factor for critical COVID-19 illness. No trends indicated any consistent effect of degree of scoliosis on increased adverse outcome likelihood.

Anterior Vertebral Body Tethering Compared with Posterior Spinal Fusion for Major Thoracic Curves

BACKGROUND

Anterior vertebral body tethering (AVBT) is an alternative to posterior spinal fusion (PSF) for the surgical treatment of scoliosis. The present study utilized a large, multicenter database and propensity matching to compare outcomes of AVBT to PSF in patients with idiopathic scoliosis.

METHODS

Patients with thoracic idiopathic scoliosis who underwent AVBT with a minimum 2-year follow-up retrospectively underwent 2 methods of propensity-guided matching to PSF patients from an idiopathic scoliosis registry. Radiographic, clinical, and Scoliosis Research Society 22-Item Questionnaire (SRS-22) data were compared preoperatively and at the ≥2-year follow-up.

RESULTS

A total of 237 AVBT patients were matched with 237 PSF patients. In the AVBT group, the mean age was 12.1 ± 1.6 years, the mean follow-up was 2.2 ± 0.5 years, 84% of patients were female, and 79% of patients had a Risser sign of 0 or 1, compared with 13.4 ± 1.4 years, 2.3 ± 0.5 years, 84% female, and 43% Risser 0 or 1 in the PSF group. The AVBT group was younger (p < 0.001), had a smaller mean thoracic curve preoperatively (48 ± 9°; range, 30° to 74°; compared with 53 ± 8°; range, 40° to 78° in the PSF group; p < 0.001), and had less initial correction (41% ± 16% correction to 28° ± 9° compared with 70% ± 11% correction to 16° ± 6° in the PSF group; p < 0.001). Thoracic deformity at the time of the latest follow-up was 27° ± 12° (range, 1° to 61°) for AVBT compared with 20° ± 7° (range, 3° to 42°) for PSF (p < 0.001). A total of 76% of AVBT patients had a thoracic curve of <35° at the latest follow-up compared with 97.4% of PSF patients (p < 0.001). A residual curve of >50° was present in 7 AVBT patients (3%), 3 of whom underwent subsequent PSF, and in 0 PSF patients (0%). Forty-six subsequent procedures were performed in 38 AVBT patients (16%), including 17 conversions to PSF and 16 revisions for excessive correction, compared with 4 revision procedures in 3 PSF patients (1.3%; p < 0.01). AVBT patients had lower median preoperative SRS-22 mental-health component scores (p < 0.01) and less improvement in the pain and self-image scores between preoperatively and the ≥2-year follow-up (p < 0.05). In the more strictly matched analysis (n = 108 each), 10% of patients in the AVBT group and 2% of patients in the PSF group required a subsequent surgical procedure.

CONCLUSIONS

At a mean follow-up of 2.2 years, 76% of thoracic idiopathic scoliosis patients who underwent AVBT had a residual curve of <35° compared with 97.4% of patients who underwent PSF. A total of 16% of cases in the AVBT group required a subsequent surgical procedure compared with 1.3% in the PSF group. An additional 4 cases (1.3%) in the AVBT group had a residual curve of >50° that may require revision or conversion to PSF.

LEVEL OF EVIDENCE

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

When successful, anterior vertebral body tethering (VBT) induces differential segmental growth of vertebrae: an in vivo study of 51 patients and 764 vertebrae

PURPOSE

This study aimed to determine (1) does vertebral body tethering (VBT) produce differential growth modulation in individual vertebrae in patients with idiopathic scoliosis, (2) does VBT change disc shape, and (3) does VBT affect total spine length?

METHODS

Patients with idiopathic scoliosis treated with VBT of the main thoracic curve and minimum 2-year follow-up were included. Vertebrae and discs were categorized as uninstrumented proximal thoracic, instrumented main thoracic, or uninstrumented thoracolumbar-lumbar. The left- and right-sided heights of each vertebra and disc were measured on subsequent radiographs to assess for differential growth. T1-T12 thoracic and T1-S1 thoracolumbar growth velocities were compared with standardized reference data.

RESULTS

Fifty-one patients (764 vertebrae and 807 discs) were analyzed. The average major curve magnitude improved from 46° ± 11° to 17° ± 11° at 2-year follow-up. Differential growth was observed in MT vertebrae, in which the left/concave side grew 2.0 ± 2.2 mm compared with 1.5 ± 2.3 mm on the right/convex (tethered) side (p < 0.001). Differential height changes were observed for all discs, but were most pronounced in instrumented MT discs, in which the right/convex sides decreased by an average of 1.2 mm each, compared with no significant height change on the left/concave side. Total spinal growth velocities were not significantly different from standard reference data.

CONCLUSION

Vertebral body tethering limits convex spinal growth as designed while permitting concave growth. Curve correction results from differential vertebral growth and decreased convex disc height. Overall spinal growth continues at the expected rate.

LEVEL OF EVIDENCE

Level IV case series.

Vertebral growth modulation by posterior dynamic deformity correction device in skeletally immature patients with moderate adolescent idiopathic scoliosis

STUDY DESIGN

Retrospective, comparative, multicenter.

INTRODUCTION

Growth modulating spinal implants are used in the management of scoliosis such as anterior vertebral body tethering. A motion-sparing posterior device (PDDC) was recently approved for the treatment of moderate AIS. The purpose of this study was to determine if the PDDC can modulate growth in skeletally immature patients with AIS.

METHODS

From a database of patients treated with the PDDC over 4 years, we identified those who had a minimum of 2 years follow-up. Pre-operative and post-operative Cobb angles and coronal plane wedging of the apical vertebra were evaluated on standing full length radiographs. Independent sample t test and one-way ANOVA with post-hoc Tukey HSD analysis was used to compare three groups in varying skeletal maturity: Risser 0-1, Risser 2-3, and Risser 4-5.

RESULTS

45 patients (14.2-years old, 11-17) were evaluated with a mean pre-op curve of 46° (35°-66°). The average preoperative major curve magnitude, of either Lenke 1 or 5 curve type, was similar among the three groups 47.6°, 46° and 41.5°. Deformity correction was similar in the three groups, with reduction to 26.4°, 20.4° and 26.2°, respectively, at final follow-up [p < 0.05]. Pre-op wedging 7.4° (3.8°-15°) was reduced after surgery to 5.7° (1°-15°) (p < 0.05). Of those patients, Risser 0-1 (n = 16) had preoperative wedging of 9.5° (6°-14.5°) that was reduced to 5.4° (1°-8°) postoperatively (p < 0.05); Risser 2-3 (n = 15) had pre-op 7.7° (4°-15°) vs. post-op 7.0° (3°-15°); Risser 4-5 (n = 14) had pre-op 4.8° (3.8°-6.5°) vs. post-op 4.7° (3.7°-6.5°). Delta Wedging in Risser 0-1 stage was significantly different than for Risser 2-3 and for Risser 4-5.

CONCLUSION

The posterior dynamic deformity correction device was able to modulate vertebral body wedging in skeletally immature patients with AIS. This was most evident in patients who were Risser 0-1. In contrast, curve correction was similar among the three groups. This finding lends support to the device's ability to modulate growth.

Comparing short-term AIS post-operative complications between ACS-NSQIP and a surgeon study group

STUDY DESIGN

Prospective cohort review.

OBJECTIVE

To compare two AIS databases to determine if a performance improvement-based surgeon group has different outcomes compared to a national database. The American College of Surgeon's National Quality Improvement Program (ACS-NSQIP) and a surgeon study group (SG) collect prospective data on AIS surgery outcomes. NSQIP offers open enrollment to all institutions, and SG membership is limited to 15 high-volume institutions, with a major initiative to improve surgeon performance. While both provide important outcome benchmarks, they may reflect outcomes that are not relatable nationwide.

METHODS

The ASC-NSQIP Pediatric Spine Fusion and SG database were queried for AIS 30- and 90-day complication data for 2014 and 2015. Prospective enrollment and a dedicated site coordinator with rigorous data quality assurance protocols existed for both registries. Outcomes were compared between groups with respect to superficial and deep surgical site infections (SSI), neurologic injury, readmission, and reoperation.

RESULTS

There were a total of 2927 AIS patients included in the ASC-NSQIP data and 721 in the SG database. Total complication rate was 9.4% NSQIP and 3.6% SG. At 90 days, there were fewer surgical site infections reported by SG than ASC-NSQIP (0.6% vs. 1.6%, p = 0.03). Similarly, there were less spinal cord injuries (0.8% vs 1.5%, p = 0.006), 30-day readmissions (0.8% vs. 2.6%, p = 0.002), and 30-day reoperations (0.6% vs. 1.7%, p = 0.02) in the SG cohort.

CONCLUSIONS

Comparison of these two data sets suggests a range of complications and readmission rates, with the SG demonstrating lower values. These results are likely multi-factorial with the performance improvement initiative of the SG playing a role. Understanding the rate and ultimate risk factors for readmission and complications from big data sources has the potential to further drive quality improvement.

LEVEL OF EVIDENCE

III.

Surface topography assessment of body shape after surgical correction in adolescent idiopathic scoliosis

HYPOTHESIS

Body surface topography (ST) improvements are associated with surgical correction in adolescent idiopathic scoliosis (AIS) and correlate with radiographic imaging.

DESIGN

Prospective observational study.

INTRODUCTION

Patients undergoing correction of AIS are most affected by body image. Radiographs have been the standard assessment tool but do not assess body shape features. ST, a validated, radiation-free assessment tool, directly represents the patient's deformity. We set out to assess ST improvements associated with surgical correction in AIS.

METHODS

Twenty-three consecutive operative AIS patients were enrolled and had radiographs and posterior ST obtained pre- and postoperatively (PO). ST changes were compared using paired t test, and correlations of ST with radiograph measurements were evaluated by linear regression.

RESULTS

Mean age at surgery was 15.0 ± 2 years, 82.6% female with mean follow-up of 1.0 year. Major Cobb angle improved from 56.91° ± 15.57° to 13.70° ± 4.89°. ST scoliosis angle corrected from 41.43° ± 11.52° to 11.78° ± 7.84° (p < .0001). Trunk length increased from 401.22 ± 32.43 to 422.30 ± 25.77 mm (Δ21.08 mm; p = .0004). Pelvic obliquity (waist asymmetry) trended toward improvement (6.0 ± 4.3 vs. 5.3 ± 7.1 mm; p = .06). Surface rotation was corrected from 17.35 ± 6.73 to 11.8 ± 4.12 mm (p < .0001), highly correlated with clinical trunk rotation (T p = .002 and TL p = .02). ST highly correlated with radiographic parameters. Sagittal balance correlated with improved function (p = .02).

CONCLUSION

ST, a radiation-free body shape assessment tool, improved with surgical correction of AIS and was highly correlated with radiographic outcomes.

Surgical management of moderate adolescent idiopathic scoliosis with a fusionless posterior dynamic deformity correction device: interim results with bridging 5-6 disc levels at 2 or more years of follow-up

OBJECTIVE

A posterior dynamic deformity correction (PDDC) system was used to correct adolescent idiopathic scoliosis (AIS) without fusion. The preliminary outcomes of bridging only 3-4 discs in patients with variable curve severity have previously been reported. This paper examines a subgroup of patients with the authors' proposed current indications for this device who were also treated with a longer construct.

METHODS

Inclusion criteria included a single AIS structural curve between 40° and 60°, curve flexibility ≤ 30°, PDDC spanning 5-6 levels, and minimum 2-year follow-up. A retrospective review was conducted and demographic and radiographic data were recorded. A successful outcome was defined as a curve magnitude of ≤ 30° at final follow-up. Any serious adverse events and reoperations were recorded.

RESULTS

Twenty-two patients who met the inclusion criteria were operated on with the PDDC in 5 medical centers. There were 19 girls and 3 boys, aged 13-17 years, with Risser grades ≥ 2. Thirteen had Lenke type 1 curves and 9 had type 5 curves. The mean preoperative curve was 47° (range 40°-55°). At a minimum of 2 years' follow-up, the mean major curve measured 25° (46% correction, p < 0.05). In 18 (82%) of 22 patients, the mean final Cobb angle measured ≤ 30° (range 15°-30°). Trunk shift was corrected by 1.5 cm (range 0.4-4.3 cm). The mean minor curve was reduced from 27° to 17° at final follow-up (35% correction, p < 0.05). For Lenke type 1 patterns, the mean 2D thoracic kyphosis was 24° preoperatively versus 27° at final follow-up (p < 0.05), and for Lenke type 5 curves, mean lumbar lordosis was 47° preoperatively versus 42° at final follow-up (p < 0.05). The mean preoperative Scoliosis Research Society-22 questionnaire score improved from 2.74 ± 0.3 at baseline to 4.31 ± 0.4 at 2 years after surgery (p < 0.0001). The mean preoperative self-image score and satisfaction scores improved from preoperative values, while other domain scores did not change significantly. Four patients (18%) underwent revision surgery because of nut loosening (n = 2), pedicle screw backup (n = 1), and ratchet malfunction (n = 1).

CONCLUSIONS

In AIS patients with a single flexible major curve up to 60°, the fusionless PDDC device achieved a satisfactory result as 82% had residual curves ≤ 30°. These findings suggest that the PDDC device may serve as an alternative to spinal fusion in select patients.

Brace treatment in adolescent idiopathic scoliosis: risk factors for failure-a literature review

Brace treatment is the most common nonoperative treatment for the prevention of curve progression in adolescent idiopathic scoliosis. The success reported in level 1 and 2 clinical trials is approximately 75%. The aim of this review was to identify the main risk factors that significantly reduce success rate of brace treatment. A literature search using the MEDLINE and Embase databases was conducted. Studies were included if they identified specific risk factor(s) for curve progression. Studies that looked at nighttime braces, superiority of one type of brace over another, the effect of physical therapy on brace performance, cadaver or nonhuman studies were excluded. A total of 1,022 articles were identified of which 25 met all of the inclusion criteria. Seven risk factors were identified: Poor brace compliance (eight studies), lack of skeletal maturity (six studies), Cobb angle over a certain threshold (six studies), poor in-brace correction (three studies), vertebral rotation (four studies), osteopenia (two studies), and thoracic curve type (two studies). Three risk factors were highly repeated in the literature which identified specific subgroups of patients who have a much higher risk to fail brace treatment and to progress to fusion. This data demonstrates that 60% to 70% of the patients referred to bracing are Risser 0 and 30% to 70% of this group will not wear the brace enough to ensure treatment efficacy. Furthermore, Risser 0 patients who reach the accelerated growth phase with a curve ≥40° are at 70% to 100% risk of curve progression to the fusion surgical threshold despite proper brace wear. Skeletally immature patients with relatively large magnitude scoliosis who are noncompliant are at a higher risk of failing brace treatment.

Body Image Disturbance Improvement After Operative Correction of Adolescent Idiopathic Scoliosis

HYPOTHESIS

Body Image Disturbance Questionnaire-Scoliosis version (BIDQ-S) is a sensitive outcomes instrument to evaluate improvements in body image-related psychosocial effects with surgical correction.

DESIGN

Prospective observational study.

INTRODUCTION

The BIDQ-S was previously validated (convergent validity, internal consistency) as a tool to assess body image-related distress and psychosocial impairment in adolescent idiopathic scoliosis (AIS). This study was conducted to evaluate responsiveness to change in the BIDQ-S associated with surgical treatment of AIS two years postoperatively to complete the validation of this questionnaire.

METHODS

Seventy-five consecutive operative AIS patients were enrolled and completed BIDQ-S and Scoliosis Research Society-22 (SRS-22) at preoperative and two-year postoperative visits. Demographic and radiographic data were collected. Preoperative and two-year postoperative BIDQ-S (1 = best, 5 = worst) and SRS-22 scores (1 = worst, 5 = best) were compared using paired t test. Correlations between BIDQ-S and SRS-22 scores were evaluated by linear regression.

RESULTS

Eighty-four percent of the subjects were females, with average age at surgery of 14.4 ± 1.6 years. The mean follow-up was 2.26 years (range 2.0-4.5). The major Cobb was corrected from 50.0° ± 7.2° to 14.2° ± 5.8° (Δ = 71.3% ± 12.1%; p < .0001). There was a significant improvement in BIDQ-S scores after surgery (1.64 ± 0.51 to 1.21 ± 0.38, p < .0001). BIDQ-S improvements were correlated with change in SRS self-image (p = .0055), activity (p = .0057), mental (p = .0018), and overall mean (p = .0007) domains. Preoperative, two-year postoperative, and Δ BIDQ-S score were not associated with major Cobb magnitude, truncal rotation, or Lenke curve type. Patients who reached SRS-22r minimal clinically important difference (MCID) in activity and self-image domains had worse preoperative BIDQ scores than those who did not reach MCID (activity 1.91 vs. 1.54 [1 = best, 5 = worst], p = .0099; self-image 2.08 vs. 1.51, p < .0001). Greater improvement in BIDQ-S was noted in patients who reached MCID in SRS-22 self-image than those who did not (Δ = 0.77 vs. 0.38, p = .0052).

CONCLUSION

BIDQ-S is responsive to surgical correction of AIS. The BIDQ-S is a valuable clinical outcome tool to assess the psychosocial effects of scoliosis in adolescents augmenting existing outcome instruments.

The Effect of the Level of Training of the First Assistant on the Outcomes of Adolescent Idiopathic Scoliosis Surgery

BACKGROUND

At academic medical centers, residents and fellows play an integral role as surgical first assistants in spinal deformity surgery. However, limited data exist on whether the experience level of the surgical assistant affects outcomes.

METHODS

We conducted a multicenter, multisurgeon study comparing perioperative and postoperative outcomes after adolescent idiopathic scoliosis (AIS) surgery for the same 11 surgeons who performed cases that were assisted by residents compared with cases that were assisted by fellows. Blood loss, operative time, duration of hospitalization, complication rates, Scoliosis Research Society (SRS)-22 questionnaire scores, and radiographic outcomes were compared between the 2 groups.

RESULTS

We evaluated outcomes for 347 surgical procedures; 118 cases were assisted by residents and 229 were assisted by fellows. Preoperative radiographic and demographic parameters were not different between the groups. The resident group had significantly more estimated blood loss than the fellow group (939 compared with 762 mL, p = 0.02). Otherwise, the perioperative characteristics were similar between the groups, including the volume of the autologous blood recovery system product that was transfused, the operative time, and the occurrence of intraoperative neuromonitoring changes. Postoperatively, the percentage correction of the Cobb angle, the number of levels that had been fused, the number of days until the discharge criteria had been met, and the rate of major complications were similar between the groups. At the 2-year follow-up, the overall and subdomain SRS-22 questionnaire scores were not different between the groups, except that patients in the resident-assisted group had slightly worse pain scores than those in the fellow-assisted group (4.3 compared with 4.5, p = 0.01).

CONCLUSIONS

The first assistant's level of training did not affect clinical or radiographic outcomes following AIS surgery.

LEVEL OF EVIDENCE

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Preclinical Bench Testing on a Novel Posterior Dynamic Deformity Correction Device for Scoliosis

STUDY DESIGN

Biomechanical test.

OBJECTIVE

To summarize the preclinical tests performed to assess the durability of a novel fusionless dynamic device for the treatment of adolescent idiopathic scoliosis (AIS).

SUMMARY OF BACKGROUND DATA

The minimal invasive deformity correction (MID-C) system is a distractible posterior dynamic deformity correction device designed to reduce scoliosis for AIS patients, to maintain curve correction, and to preserve spinal motion. To overcome the challenges of wear and fatigue of this procedure, the system has two unique features: polyaxial joints at the rod-screw interface and a ceramic coating of the moving parts.

METHODS

Five biomechanical tests were performed: Static compression to failure, fatigue loading per ASTM F 1717 with 5.5-mm screws for 10 million cycles (MC) at 5 Hz, wear assessment, wear test of the polyaxial joint under 100 N load for 10 MC, and wear particle implantation in rabbits.

RESULTS

The system failed through buckling of the rod with loads over 3000 N (400% of human body weight). Dynamically, the system maintained 700 N for 10 MC with 5.5 mm screws. The maximum total steady-state wear rate was 0.074 mg/MC (0.03 per polyaxial joint and 0.014 mg/MC for the ratchet mechanism). Histologic evaluation of the particle injection sites indicated no difference in the local tissue response between the control and test articles. At 3 and 6 months postinjection, there were neither adverse local effects nor systemic effects observed.

CONCLUSIONS

The unique design features of the MID-C system, based on polyaxial joints and ceramic coating, resulted in favorable static, fatigue, and wear resistance properties. Wear properties were superior to those published for artificial spinal discs. Long-term outcomes from clinical use will be required to correlate these bench tests to the in vivo reality of clinical use.

LEVEL OF EVIDENCE

Level V.

In Search of the Ever-Elusive Postoperative Shoulder Balance: Is the T2 UIV the Key?

STUDY DESIGN

Multicenter review of prospectively collected data.

OBJECTIVE

The purpose of this study was to evaluate whether a UIV of T2 reliably results in level shoulders postoperatively.

SUMMARY OF BACKGROUND DATA

Adolescent idiopathic scoliosis (AIS) patients with a risk of a high left shoulder postoperatively are generally recommended to have instrumentation to T2, those with neutral shoulders a T3 UIV, and those with an elevated right shoulder are recommended a UIV of T4 or below in order to achieve postoperative shoulder balance.

METHODS

A prospective, multicenter AIS database was queried for subjects with minimum two-year follow-up who underwent posterior spinal fusion to correct their main thoracic deformity. Subjects were grouped based on their proximal fusion level. A high shoulder was defined as >1 cm difference on radiographs.

RESULTS

A total of 626 subjects met inclusion criteria and were divided by UIVs of T2 189, T3 205, and T4 232. Preoperatively, the groups had similar rates of balanced shoulders (T2 47%, T3 49%, T4 45%) and high left shoulders (T2 8.5%, T3 8.8%, and T4 7.3%). Postoperatively, there was a greater percentage of postoperative shoulder imbalance for T2 (45%) and T3 (48%) UIV groups as compared to T4 (34%, p = .008). As expected, the T2 (46%) and T3 (49%) groups had significantly better upper thoracic curve correction as compared to the T4 group (42%, p < .001).

CONCLUSIONS

The selection of a T4 UIV results in more shoulder balance postoperatively than T2 or T3, regardless of which shoulder was elevated preoperatively. The selection of a T2 UIV does not guarantee postoperative shoulder balance following posterior treatment of main thoracic curves; however, when compared to the more caudal UIV of T4, an improved upper thoracic curve correction can be anticipated.

LEVEL OF EVIDENCE

Level 3.

Biomechanical Comparison of the Load-Sharing Capacity of High and Low Implant Density Constructs With Three Types of Pedicle Screws for the Instrumentation of Adolescent Idiopathic Scoliosis

STUDY DESIGN

Biomechanical numerical simulation analysis of implant design and density in adolescent idiopathic scoliosis posterior instrumentation.

OBJECTIVES

To evaluate the combined effect of pedicle screw design and density on deformity correction and construct load-sharing capacity.

SUMMARY OF BACKGROUND DATA

Screw density is an area of popular study because of the impact of cost and potential patient morbidity of higher-density constructs. Using fewer screws raises concern about reduced correction and greater forces on each screw.

METHODS

Personalized spinal numerical models were created for five patients. The correction techniques from five spine surgeons using both a high- and a low-density implant pattern (2 vs. 1.4 ± 0.22 screws/level) with uniaxial, multiaxial, and favored angle screws were simulated. The predicted correction and forces sustained by the implants were compared. The postoperative load-sharing capacity of a high- and a low-density construct, with or without crosslinks, was compared by simulating daily activities motions.

RESULTS

The major coronal curve correction was similar with high- and low-density constructs (73% ± 10% vs. 72% ± 10%; p > .05) but was higher when using uniaxial (77% ± 8%) compared to multiaxial (69% ± 11%) and favored angle screws (71% ± 10%; p = .009). High- and low-density constructs sustained similar intraoperative peak forces (305 ± 61 N vs. 301 ± 73 N; p = .23) regardless of screw design (all p > .05). Multiaxial and favored angle screws reduced the peak axial force by 23% and 38% compared to uniaxial screws (p = .007). The high-density construct reduced the postoperative loads sustained by each implant by 31% (p = .006). Crosslinks had no effect on load sharing (p = .23).

CONCLUSION

High- and low-density implant patterns achieved similar coronal correction with equivalent capacity to share corrective forces regardless of the screw design. Increased degrees of freedom of the screw head reduces the capacity to correct coronal deformity but generates lower bone-screw forces. The reduced number of screws increased the postoperative forces sustained by each screw, but its effect on potential complications requires further investigations.

LEVEL OF EVIDENCE

Level 4.

Major Complications at Two Years After Surgery Impact SRS Scores for Adolescent Idiopathic Scoliosis Patients

STUDY DESIGN

Retrospective review of prospectively collected data.

OBJECTIVE

To determine whether adolescent idiopathic scoliosis (AIS) patients with active complications at two-year follow-up demonstrate lower Scoliosis Research Society (SRS-22) questionnaire scores.

SUMMARY OF BACKGROUND DATA

There is limited evidence as to whether the SRS-22 is sensitive to complications in postoperative AIS patients.

METHODS

Surgical patients with SRS-22 scores completed at two-year follow-up were included. Five groups were created: no complication, minor complication resolved by 2 years, major complication resolved by 2 years, minor complication active, and major complication active at 2 years. Likelihood of reaching a minimal clinically important difference (MCID) for pain (0.20) and self-image (0.98) was evaluated.

RESULTS

1,481 patients were identified. Major complications active at two years existed in 2.2% of patients. These patients had the lowest score in all domains and total scores (p < .05). If a minor complication was active, scores were impacted for pain, self-image, satisfaction, and total (p < .05). No differences were found between no complication and resolved complications. Patients with active major complications were more likely to have a pain score that worsened from pre- to two years reaching MCID (52%) compared to the other four groups (range 18%-29%, odds ratio [OR] 3.6, p < .001). They also had a nonsignificant decreased rate of improvement of self-image score at an MCID level (42% vs. range 51%-66%, OR 0.56, p = .10).

CONCLUSIONS

When timing is considered, the SRS-22 demonstrates the ability to discriminate between patients with and without a complication. Active experience of a major complication impacted SRS-22 scores, in particular, the rate of worsening scores for pain, self-image, function, and total score.

LEVEL OF EVIDENCE

Level III.

Surgery for the Adolescent Idiopathic Scoliosis Patients After Skeletal Maturity: Early Versus Late Surgery

INTRODUCTION

Informed decision making for operative treatment of the skeletally mature adolescent idiopathic scoliosis (AIS) patient meeting surgical indications requires a discussion of differences in operative morbidity in adult scoliosis versus AIS. This study evaluated differences in operative data and outcomes between AIS and adult scoliosis patients based on an estimated natural history of curve progression.

METHODS

Twenty-eight adult scoliosis patients (43.7 ± 15.8 years; 93% F) were 1:2 matched with 56 (Risser 4/5) AIS patients (15.7 ± 2.1 years) based on gender and curve type as vetted by 5 surgeons' consensus in committee. Curve progression of 0.3°/year for the first 10 years following skeletal maturity and a 0.5°/year thereafter was assumed to estimate curve progression from AIS to adulthood for the adult counterpart. Operative data, complications, and quality of life (Scoliosis Research Society [SRS-22r] questionnaire) measures were evaluated, with a minimum 2-year follow-up.

RESULTS

Postoperative major Cobb and percentage correction were similar between adult versus AIS, whereas operative time, percentage estimated blood loss (EBL; % total blood volume), length of hospital stay (LOS), and total spine levels fused were greater for adult patients (p < .05). No difference was found in EBL, operative time, or LOS when normalized by levels fused. Ten (36%) adult scoliosis patients were fused to the pelvis compared with none in AIS (p < .0001). Major complication rate was higher for adult versus AIS (25% vs. 5.4%; p < .05). Preoperative SRS-22r scores were worse for adult patients; however, they demonstrated greater improvement in SRS-22r than the AIS cohort at final follow-up. A higher percentage of adult patients reached the MCID in self-image domain than the AIS patients (92.3% vs. 61.8%; p = .0040).

CONCLUSION

Treatment of the adult scoliosis patient who has undergone an estimated natural history of progression is characterized by greater levels fused, operative time, and higher complication rates than the AIS counterpart. Longer-term follow-up of AIS is needed to define the benefits of early intervention of relatively asymptomatic adolescent patients versus late treatment of symptomatic disease in the adult.

Reciprocal Changes in Sagittal Alignment With Operative Treatment of Adolescent Scheuermann Kyphosis-Prospective Evaluation of 96 Patients

INTRODUCTION

Sagittal alignment abnormalities in Scheuermann kyphosis (SK) strongly correlate with quality of life measures. The changes in spinopelvic parameters after posterior spinal fusion have not been adequately studied. This study is to evaluate the reciprocal changes in spinopelvic parameters following surgical correction for SK.

METHODS

Ninety-six operative SK patients (65% male; age 16 years) with minimum 2-year follow-up were identified in the prospective multicenter study. Changes in spinopelvic parameters and the incidence of proximal (PJK) and distal (DJK) junctional kyphosis were assessed as were changes in Scoliosis Research Society-22 (SRS-22) questionnaire scores.

RESULTS

Maximum kyphosis improved from 74.4° to 46.1° (p < .0001), and lumbar lordosis was reduced by 10° (-63.3° to -53.3°; p < .0001) at 2-year postoperation. Pelvic tilt, sacral slope, and sagittal vertical axis remained unchanged. PJK and DJK incidence were 24.2% and 0%, respectively. In patients with PI <45°, patients who developed PJK had greater postoperative T2-T12 (54.8° vs. 44.2°, p = .0019), and postoperative maximum kyphosis (56.4° vs. 44.6°, p = .0005) than those without PJK. In patients with PI ≥45°, patients with PJK had less postoperative T5-T12 than those without (23.6° vs. 32.9°, p = .019). Thoracic and lumbar apices migrated closer to the gravity line after surgery (-10.06 to -4.87 mm, p < .0001, and 2.28 to 2.10 mm, p = .001, respectively). Apex location was normalized to between T5-T8 in 68.5% of patients with a preoperative apex caudal to T8, whereas 90% of patients with a preoperative apex between T5 and T8 remained unchanged. Changes in thoracic apex location and lumbar apex translation were associated with improvements in the SRS function domain.

CONCLUSION

PJK occurred in 1 in 4 patients, a lower incidence than previously reported perhaps because of improved techniques and planning. Both thoracic and lumbar apices migrated closer to the gravity line, and preoperative apices caudal to T8 normalized in more than two-thirds of patients, resulting in improved postoperative function. Individualizing kyphosis correction to prevent kyphosis and PI mismatch may be protective against PJK.

Preliminary Analysis of Factors Associated with Blood Loss in Neuromuscular Scoliosis Surgery

STUDY DESIGN

A retrospective review was conducted of 57 consecutive patients (26 female; mean age: 16.6 years) who underwent posterior or combined anterior-posterior spinal fusion for neuromuscular scoliosis (NMS) from 2006 and 2007.

OBJECTIVES

We aimed to assess which patient and surgical factors are predictive of increased blood loss and transfusion requirements during spinal fusion for NMS.

BACKGROUND

Spinal fusion surgery in patients with NMS has been associated with significant intraoperative blood loss and transfusion requirements. Specific factors predictive of greater blood loss have not been delineated; recognizing these factors will assist predicting the need for blood products and antifibrinolytics.

METHODS

Data gathered included demographic, operative (operative time, levels fused, estimated blood loss, cell saver transfused, IV fluids transfused, and units transfused), and laboratory parameters (hemoglobin, hematocrit, platelet count, prothrombin time, partial prothrombin time, and international normalized ratio). Multivariate linear regression was used to identify parameters associated with greater intraoperative blood loss and transfusion requirements.

RESULTS

Eighty-three percent of patients underwent primary surgery with mean levels fused of 13.5. Regression analysis showed a statistically significant increase in blood loss with age (p = 0.00), operative time (p = 0.00), and postoperative platelets (p = 0.016). Each year of increasing age corresponded with an increase of 50 cc of estimated blood loss (EBL). Each additional hour of operative time was associated with an additional EBL of 147.7 cc. Each additional unit of postoperative platelets was associated with an EBL decrease of 2.8 cc. Units transfused increased with age (p = 0.00): each year of increasing age corresponded with an increase of 0.04 units of blood transfused.

CONCLUSIONS

Patients with NMS remain a challenging group of patients to treat. We find that age, operative time, and postoperative platelets are predictive of increased blood loss while only age was related to greater transfused units. Our findings may predict the need for blood products and antifibrinolytic agents preoperatively in this heterogeneous population, especially as patients age.

Antifibrinolytic Therapy in Surgery for Adolescent Idiopathic Scoliosis Does the Level 1 Evidence Translate to Practice?

INTRODUCTION

Previous randomized controlled trials have demonstrated the efficacy of antifibrinolytic agents in the reduction of intraoperative blood loss in adolescent idiopathic scoliosis (AIS) surgery. Tranexamic acid (TXA) was found to be more effective at reducing total blood loss compared with epsilon-aminocaproic acid (AM) than placebo. We set out to study whether or not the level 1 evidence can be corroborated in a large multicenter, multisurgeon cohort.

METHODS

Estimated blood loss (EBL), cell saver transfused, and percent of total blood volume (%EBL) was retrospectively assessed from a prospective-collected multicenter AIS registry. Volume of allogeneic blood transfusion data was not uniformly available. The cohort was divided into: 1. TXA (N = 525; 2006-2014), 2. Amicar (N = 117; 2005- 2014), and 3. no antifibrinolytic (N = 1127; 2005-2013) groups. Comparisons between the three groups and between antifibrinolytic (Amicar or TXA) versus no antifibrinolytic (NA) groups were performed using ANOVA with Bonferroni correction and the t-test, respectively. Multivariate analysis was used to control for surgical and surgeon factors.

RESULTS

EBL, %EBL, and cell saver transfused was significantly lower in TXA (742.3 mL, 21.3% and 191.8 mL, respectively) than NA (1,010.6 mL, 29.8% and 276.6 mL, respectively) and AM (1,420.6 mL, 38.9% and 456.0 mL, respectively), (p < 0.0001), with AM having the greatest values among the three groups. These parameters were normalized by number of levels fused and Cobb magnitude. A similar pattern was observed, with AM having the highest normalized values and TXA group the lowest among all three groups. After further controlling for surgeon, total operative time, and osteotomy performed, multivariable analysis revealed that EBL/level, %EBL/level, and cell saver/level transfused were significantly lower in the TXA group compared to the NA group (p = 0.0014, p = 0.0058, and p = 0.0031, respectively), whereas, no difference was observed between the AM and NA groups (p = 0.1028, p = 0.2523, and p = 0.5274, respectively). The differences between TXA and AM were diminished (p = 0.5512, p = 0.6751, and p = 0.0978, respectively).

CONCLUSION

Intraoperative administration of TXA significantly reduces EBL, %EBL, and cell saver transfused during AIS surgery. After taking operative and surgeon factors into consideration, %EBL was not significantly different between TXA and Amicar groups in the practice setting.

A Practical Guide to Avoiding and Managing Complications in Pediatric Spinal Deformity Surgery

Despite recent research and improvements in spinal implants, complications remain frequent in patients who undergo pediatric spinal deformity surgery. Although the rate of neurologic injury after pediatric spinal deformity surgery is low, the rate of surgical site infection after pediatric spinal deformity surgery is high, particularly in patients who have neuromuscular scoliosis. Although symptomatic implant complications that require revision surgery are rare with the use of modern spinal fusion constructs, they are common in patients who have early-onset scoliosis. Patients who have perioperative respiratory or gastrointestinal complications benefit from early recognition and supportive treatment. The cause of perioperative complications in patients who undergo pediatric spinal deformity surgery often is multifactorial; therefore, surgeons should understand the numerous risk factors for and strategies for the prevention of pediatric spinal deformity surgery complications.

Importance of patient-reported individualized goals when assessing outcomes for adult spinal deformity (ASD): initial experience with a Patient Generated Index (PGI)

BACKGROUND CONTEXT

Current metrics to assess patients' health-related quality of life (HRQOL) may not reflect a true change in the patients' specific perception of what is most important to them.

PURPOSE

This study aimed to describe the initial experience of a Patient Generated Index (PGI) in which patients create their own outcome domains.

STUDY DESIGN

This is a single-center prospective study.

PATIENT SAMPLE

Patients with adult spinal deformity (ASD) comprise the study sample.

OUTCOME MEASURES

Oswestry Disability Index (ODI), Short Form-36 (SF-36 Physical Component Score [PCS] and Mental Component Score [MCS]), Scoliosis Research Society-22r (SRS-22r), and PGI.

METHODS

Oswestry Disability Index, SF-36, SRS-22r, and PGI were administered preoperatively and postoperatively at 6 weeks, 3 months, 6 months, and 1 and 2 years. PGI correlations with ODI, SF-36, SRS total score, free-text frequency analysis of PGI exact response with text in ODI and SRS-22r questionnaires, and the responsiveness (effect size [ES]) of the HRQOL metrics were analyzed. No funding was used for this study and there are no conflicts of interest.

RESULTS

A total of 59 patients with 209 clinical encounters produced 370 PGI written response topics that included affect or emotions, relationships, activities of daily life, personal care, work, and hobbies. Mean preoperative PGI score was 18.6±13.5 (0-71.7 out of 100 [best]), and mean scores significantly improved at every postoperative time point (p<.05). Preoperative PGI scores significantly correlated with preoperative ODI (r=-0.28, p=.03), MCS (r=0.48, p<.01), and SRS total (r=0.57, p<.01). Postoperative PGI scores correlated with all HRQOL measures (p<.0001): ODI (r=-0.65), PCS (r=0.50), MCS (r=0.55), and SRS total (r=0.63). PGI responses exactly matched ODI and SRS-22r text at 47.8% and 35.4%, respectively, and at 63.2% and 58.9%, respectively, for categories. Patient Generated Index ES at a minimum of 1-year follow-up was -2.39, indicating substantial responsiveness (|ES|>0.8). Effect sizes for ODI, SRS-22r total, SF-36 PCS, and SF-36 MCS were 2.16, -2.06, -2.05, and -0.80, respectively.

CONCLUSIONS

The PGI is easy to administer and offers additional information about the patients' perspective not captured in standard HRQOL metrics. Patient Generated Index scores correlated with all of the standard HRQOL scores and were more responsive than ODI, SF-36, and SRS-22r, suggesting that the PGI may be a step closer to one HRQOL measure that better encompasses concerns and goals of the individual patients.

Perioperative and Delayed Major Complications Following Surgical Treatment of Adolescent Idiopathic Scoliosis

BACKGROUND

Reporting accurate surgical complication rates to patients and their families is important in the management of adolescent idiopathic scoliosis (AIS). In this study, we report the rate of major complications following the surgical treatment of AIS both in the perioperative period and among patients with a minimum of 2 years of follow-up.

METHODS

We reviewed the prospectively collected data of a multicenter registry of patients who underwent surgical treatment of AIS during the period of 1995 to 2014 in order to identify all complications. A complication was defined as "major" if it resulted in reoperation or in spinal cord or nerve root injury, or was life-threatening. A total of 3,582 patients with preoperative and early postoperative data (4 to 6 weeks of follow-up) were included. A subset of 2,220 patients with a minimum of 2 years of follow-up comprised the cohort for delayed complications. Overall complication rates were calculated, as was the percentage of complications according to the year of the index surgery and type of surgical approach.

RESULTS

The mean age of the 3,582 patients at the time of surgery was 14.8 ± 2.2 years. The average major curve magnitude was 56° ± 13° for thoracic curves and 51° ± 11° for lumbar. In 365 patients, anterior spinal fusion (ASF) with instrumentation was performed, and in 3,217 patients, posterior spinal fusion (PSF) with instrumentation was performed; 142 patients in the PSF group underwent concomitant anterior release. There were 192 major complications, with 93 (2.6%) occurring perioperatively. Perioperative complications included wound-related (1.0% of the patients), neurologic (0.5%), pulmonary (0.4%), instrumentation-related (0.4%), and gastrointestinal (0.2%) complications. One patient died. The mean annual perioperative major complication rate based on the year of surgery ranged from 0% to 10.5%. The complication rate by surgical approach was 3.0% for ASF and 2.6% for PSF (2.4% for PSF only and 5.6% for PSF with anterior release). The major complication rate for the 2,220 patients with at least 2 years of follow-up was 4.1%; all but 1 had a reoperation (4.1%). The majority of these major complications were wound and instrumentation-related (1.9% and 0.8%, respectively).

CONCLUSIONS

After surgery for AIS, a 2.6% rate of perioperative major complications and a 4.1% rate of major complications at 2 or more years after surgery can be anticipated. The complication rate decreased over the period of study.

LEVEL OF EVIDENCE

Therapeutic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Resource Utilization in Adolescent Idiopathic Scoliosis Surgery: Is There Opportunity for Standardization?

INTRODUCTION

Recent healthcare reforms have raised the importance of cost and value in the management of disease. Value is a function of benefit and cost. Understanding variability in resources utilized by individual surgeons to achieve similar outcomes may provide an opportunity for cutting costs though greater standardization. The purpose of this study is to evaluate differences in use of implants and hospital resources among surgeons performing adolescent idiopathic scoliosis (AIS) surgery.

METHODS

A multicenter prospective AIS operative database was queried. Patients were matched for Lenke curve type and curve magnitude, resulting in 5 surgeons and 35 matched groups (N = 175). Mean patient age was 14.9 years and curve magnitude 50°. Parameters of interest were compared between surgeons via ANOVA and Bonferroni pairwise comparison.

RESULTS

There was no significant difference in percentage curve correction or levels fused between surgeons. Significant differences between surgeons were found for percentage posterior approach, operative time, length of stay (LOS), estimated blood loss (EBL), cell saver transfused, rod material, screw density, number of screws, use of antifibrinolytics, and cessation of intravenous analgesics. Despite differences in EBL and cell saver transfused, there were no differences in allogenic blood (blood bank) use.

CONCLUSION

Significant variability in resource utilization was noted between surgeons performing AIS operations, although radiographic results were uniform. Standardization of resource utilization and cost containment opportunities include implant usage, rod material, LOS, and transition to oral analgesics, as these factors are the largest contributors to cost in AIS surgery.

Risk Factors of Proximal Junctional Kyphosis in Adolescent Idiopathic Scoliosis-The Pelvis and Other Considerations

STUDY DESIGN

Prospective multicenter database study.

OBJECTIVES

To assess the incidence of proximal junctional kyphosis (PJK) in operative adolescent idiopathic scoliosis (AIS) using contemporary surgical techniques and to identify risk factors for PJK.

SUMMARY OF BACKGROUND DATA

The incidence of PJK has been reported as high as 46% in AIS. Factors associated with PJK have been incompletely explored.

METHODS

Prospectively enrolled 851 AIS patients (2000-2011, 78.5% female, average 14.4 years) were evaluated 2 years postoperatively. Radiographic and sagittal spinopelvic parameters and rod contour angle (RCA), a new measure that reflects the proximal contouring of the rod, were independently evaluated for association with PJK based on Lenke type. Multivariate logistic regression with backward elimination was performed to identify risk factors for PJK.

RESULTS

Overall PJK incidence was 7.05% and varies based on Lenke type (Lenke 1, 6.35%; Lenke 2 and 4, 4.39%; Lenke 3 and 6, 11.64%; and Lenke 5, 8.49%; p = .06). Among patients with Lenke 1 curves, risk factors for PJK were loss of kyphosis after surgery, and stopping caudal to the upper end vertebra (UEV). The risk of developing PJK increases by 7.1% with each lost degree of kyphosis compared with preoperation that occurs after the instrumentation is placed. For Lenke 2 and 4 curves, loss of kyphosis and more lordotic (negative) RCA were risk factors for PJK. For Lenke 3 and 6 curves, larger preoperative T5-T12 kyphosis was the only significant risk factor for PJK. Upper instrumented vertebra (UIV) at or cephalad to the UEV was associated with increased risk of PJK in Lenke 5 curves, which was contrary to the finding for Lenke 1 curves. No significant correlation was found between sagittal pelvic parameters and developing PJK.

CONCLUSION

The incidence of PJK in patients after surgery for AIS is 7.05% and varies based on Lenke type. Loss of kyphosis, larger preoperative kyphosis, UIV caudal to the proximal UEV (Lenke 1), UIV at or cephalad to the UEV (Lenke 5), and decreased RCA were the major risk factors for PJK in AIS.

LEVEL OF EVIDENCE

Level II.

MRI Screening in Operative Scheuermann Kyphosis: Is it Necessary?

STUDY DESIGN

Patients with preoperative spine magnetic resonance imaging (MRI) studies from a prospective multicenter study of operative adolescent Scheuermann kyphosis (SK).

OBJECTIVES

To investigate the usefulness of MRI screening in operative planning for SK surgeries.

SUMMARY OF BACKGROUND DATA

Neural axis abnormalities in operative SK have not been previously studied with MRI screening, despite its use.

METHODS

One orthopedic surgeon and two radiologists evaluated all images retrospectively. Radiographs were evaluated for kyphosis apex and magnitude. MRIs were evaluated for spinal cord abnormalities, epidural lipomatosis, location and number of vertebral wedging, Schmorl nodes and posterior disc herniations, frequency of spondylolysis, etc. The relationship of these pathologies to the kyphosis apex was explored. This group was compared to a surgical SK group without preoperative MRIs.

RESULTS

Eighty-six patients with MRIs, mean age 16.3 years, 64% male, and a mean preoperative kyphosis of 75.9° were evaluated. There were 17 spinal cord abnormalities. Low-lying conus was found in 2 patients, and syrinx in 15 (no Chiari malformations). Epidural lipomatosis was found in 49 patients, average of 5.7 levels. Anterior vertebral wedging occurred in all (mean 4.7 levels). Posterior disc herniations averaged 5.2 levels/patient and 1.8 levels caudad to the apex. Spondylolysis was reported in 8.1%. Four cases (4.7%) had the operative plan changed as a result of the preoperative MRI: two due to neural compression, one due to disc herniation and one due to a spinal cord draped over the apex. Thirty-one patients did not receive an MRI; there were no significant differences between the two groups. The rate of postoperative neurologic change was 3.5% in the MRI group and 3.2% in the no-MRI group.

CONCLUSIONS

Based on 4.7% of cases requiring a change in the operative plan as a result of preoperative MRI, the authors recommend considering performing screening MRI in operative SK patients.

An Operative Complexity Index Shows Higher Volume Hospitals and Surgeons Perform More Complex Adult Spine Deformity Operations

BACKGROUND

Though previous studies have shown improved outcomes associated with higher volume surgeons and hospitals, this may not be replicated in ASDS due to case complexity variation. We hypothesized that high-volume surgeons perform more complex surgeries. Therefore, we defined an Operative Complexity Index (OCI), specifically for the National Inpatient Samples (NIS) data, which provides information on in-hospital postoperative complications, to assess rates of adult spine deformity surgery (ASDS) cases as they relate to surgeon and hospital operative volume.

METHODS

The 2001 to 2010 NIS was queried for patients greater than 21 years of age with in-hospital stays, including a spine arthrodesis for a diagnosis of scoliosis. Surgeon and hospital identifiers were used to allocate records into volume quartiles by number of surgeries per year. The OCI was devised considering the number of fusion levels, surgical approach, revision status, and use of osteotomy. The index was validated using blood-loss-related diagnostic and procedural codes. One-way ANOVA assessed continuous measures. Chi-square assessed categorical measures.

RESULTS

141,357 ASDS cases met the inclusion criteria. High-volume surgeons performed a higher rate of longfusions (> 8 levels), revision surgeries, and surgeries requiring osteotomy. The OCI showed weak, but significant, correlation with blood loss values: acute blood loss anemia (r = 0.21) and treatment with blood products (r = 0.12) (p < 0.001). High OCI also was also associated with increased length of stay (r = 0.27) and total charges (r = 0.41) (p < 0.001).

CONCLUSIONS

The operative complexity index (OCI) for ASDS increases with high-volume surgeons and centers, indicating it can be useful to adjust for surgical invasiveness in the NIS database. Operative complexity must be considered when evaluating patient safety and quality indices among hospitals and surgeons.

Pre-Operative Autologous Blood Donation Does Not Affect Pre-Incision Hematocrit in Adolescent Idiopathic Scoliosis Patients. A Retrospective Cohort of a Prospective Randomized Trial

BACKGROUND

Pre-donation of autologous blood prior to spine fusion for adolescent idiopathic scoliosis (AIS) has been used in deformity surgery. The effect of pre-donation on pre-operative hematocrit (Hct) remains debated. Multiple factors may influence pre-operative Hct including intravascular volume status, patient factors, and timing of pre-operative blood donation. The purpose of this study was to determine if pre-donation significantly lowers pre-incision Hct in AIS patients.

METHODS

A retrospective cohort study of a Level-1 prospective randomized trial was conducted. 125 patients from the homogeneous population were included. AIS patients undergoing a posterior only spinal fusion for AIS were separated into two groups based on their pre-operative blood donation history. Demographic variables, pre-incision Hct, and transfusion rates were compared between the two groups using the Student's T-test.

RESULTS

Pre-donation and non pre-donation groups had 28 and 97 patients, respectively. Pre-donation group was 75% female (21F, 7M) and non pre-donation group was 78% female (76F, 21M). There was no difference between pre-donation and non pre-donation groups in mean age (15.6 ± 2.2 vs 14.8 ± 2.2, p = 0.081), BMI (23.1 ± 4.2 vs 21.7 ± 5.3, p = 0.219), and pre-incision Hct (32.8 ± 3.4 vs 33.8 ± 3.1, p = 0.628). The overall transfusion rates were equivalent (32.1± 48.0% vs 25.8 ± 44.0%, p = 0.509), however, the rate of allogenic transfusion for the pre-donation group was significantly lower (3.6 ± 18.9% vs 25.8 ± 44.0%, p = 0.011).

CONCLUSIONS

This study supports the use of pre-donation for AIS, without a significant drop in pre-incision Hct. Patients that donate are also much less likely to be exposed to allogenic blood. There may be a surgeon bias to recommend pre-donation in patients with a larger BMI and older age. Future studies are needed from a larger population of patients including those with non-AIS pathology.

LEVEL OF EVIDENCE

Level III.

Reversible Intraoperative Neurophysiologic Monitoring Alerts in Patients Undergoing Arthrodesis for Adolescent Idiopathic Scoliosis: What Are the Outcomes of Surgery?

BACKGROUND

Confidence in intraoperative neurophysiologic monitoring (IONM) data can allow scoliosis surgeons to proceed with surgery even after a monitoring alert, assuming the recovery of signals. We sought to determine the outcomes of surgical treatment of adolescent idiopathic scoliosis (AIS) after a notable IONM alert.

METHODS

We identified 676 patients who underwent arthrodesis with use of IONM for the treatment of AIS. The patients were divided into 2 cohorts: those who experienced a lower-extremity IONM alert and those who did not. An alert was defined as a notable change in IONM data, specifically, a ≥50% drop in somatosensory evoked potentials (SSEPs) and/or in transcranial motor evoked potentials (tcMEPs).

RESULTS

Of the 676 patients, 36 (5.3%) experienced IONM alerts. Those patients had a larger preoperative major Cobb angle (mean of 61° ± 13° compared with 55° ± 12° for the no-alert group; p < 0.01), a greater number of levels fused (mean of 12 ± 2 compared with 11 ± 2; p < 0.01), a longer operative duration (mean of 357 ± 157 minutes compared with 298 ± 117 minutes; p < 0.01), a higher estimated blood loss (1,857 ± 1,323 mL compared with 999 ± 796 mL; p < 0.01), and a greater volume of autologous blood transfused (mean of 527 ± 525 mL compared with 268 ± 327 mL; p < 0.01). Among patients who experienced an alert and had a completed operation (34 of 36 patients), mean postoperative radiographic measurements were similar to those of the no-alert group in terms of the percentage of correction of the major Cobb angle (alert, 66% ± 13%; no alert, 64% ± 19%; p = 0.53) and of rib prominence (alert, 49% ± 36%; no alert, 47% ± 46%; p = 0.83) and measurement of thoracic kyphosis (alert, 23° ± 10°; no alert, 22° ± 2°; p = 0.58). The Scoliosis Research Society (SRS)-22 outcome scores were also similar between the 2 cohorts.

CONCLUSIONS

Notable IONM changes occurred in 5.3% of the patients who underwent arthrodesis for AIS. Those patients had larger preoperative deformity, a longer operative duration, a greater number of levels fused, a higher estimated blood loss, and a greater volume of autologous blood transfused. Return of IONM data guided the surgeon to safely complete the procedure in 34 of 36 patients, with correction similar to that of patients who did not experience an alert.

LEVEL OF EVIDENCE

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

Analysis of Postoperative Thoracolumbar Spine Infections in a Prospective Randomized Controlled Trial Using the Centers for Disease Control Surgical Site Infection Criteria

INTRODUCTION

Wound infections following spinal surgery place a high toll on both the patient and the healthcare system. Although several large series studies have examined the incidence and distribution of spinal wound infection, the applicability of these studies varies greatly since nearly every study is either retrospective and/or lacks standard inclusion criteria for defining surgical site infection. To address this void, we present results from prospectively gathered thoracolumbar spine surgery data for which the Centers for Disease Control (CDC) criteria were stringently applied to define a surgical site infection (SSI).

METHODS

A prospective randomized trial of 314 patients who underwent multilevel thoracolumbar spinal surgery with instrumentation followed by postoperative drain placement was completed (Takemoto et al., 2015). The trial consisted of two antibiotic arms: one for 24-hours, and the other for the duration of the drain; no differences were found between the arms. All infections meeting CDC criteria for SSI were included.

RESULTS

A total of 40 infections met CDC criteria for SSI, for an overall incidence of 12.7%. Of these, 20 (50%) were culture-positive. The most common organism was Staphylococcus aureus (4 total: methicillin-sensitive=2; methicillin-resistant=2), followed by coagulase-negative Staphylococcus (3 cases), Propionibacterium acnes and Escherichia coli (2 cases each). Six infections grew multiple organisms, most commonly involving coagulase-negative staphylococcus and enterococcus.

CONCLUSIONS

Our findings indicate that thoracolumbar SSI occurs at the higher end of the range cited in the literature (2-13%), which is largely based on retrospective data not subjected to the inclusivity of SSI as defined by the CDC. The three most common organisms in our analysis (S. aureus, P. acnes, E. coli) are consistent with previous reports. Staphylococcus aureus continues to be the most common causative organism and continued vigilance and searching for preventive measures need to be a high priority. This study provides Level I evidence.

What would be the annual cost savings if fewer screws were used in adolescent idiopathic scoliosis treatment in the US?

OBJECT

There is substantial heterogeneity in the number of screws used per level fused in adolescent idiopathic scoliosis (AIS) surgery. Assuming equivalent clinical outcomes, the potential cost savings of using fewer pedicle screws were estimated using a medical decision model with sensitivity analysis.

METHODS

Descriptive analyses explored the annual costs for 5710 AIS inpatient stays using discharge data from the 2009 Kids’ Inpatient Database (Healthcare Cost and Utilization Project, Agency for Healthcare Research and Quality), which is a national all-payer inpatient database. Patients between 10 and 17 years of age were identified using the ICD-9-CM code for idiopathic scoliosis (737.30). All inpatient stays were assumed to represent 10-level fusions with pedicle screws for AIS. High screw density was defined at 1.8 screws per level fused, and the standard screw density was defined as 1.48 screws per level fused. The surgical return for screw malposition was set at $23,762. A sensitivity analysis was performed by varying the cost per screw ($600–$1000) and the rate of surgical revisions for screw malposition (0.117%–0.483% of screws; 0.8%–4.3% of patients). The reported outcomes include estimated prevented malpositioned screws (set at 5.1%), averted revision surgeries, and annual cost savings in 2009 US dollars, assuming similar clinical outcomes (rates of complications, revision) using a standard- versus high-density pattern.

RESULTS

The total annual costs for 5710 AIS hospital stays was $278 million ($48,900 per patient). Substituting a high for a standard screw density yields 3.2 fewer screws implanted per patient, with 932 malpositioned screws prevented and 21 to 88 revision surgeries for implant malposition averted, and a potential annual cost savings of $11 million to $20 million (4%–7% reduction in the total cost of AIS hospitalizations).

CONCLUSIONS

Reducing the number of screws used in scoliosis surgery could potentially decrease national AIS hospitalization costs by up to 7%, which may improve the safety and efficiency of care. However, such a screw construct must first be proven safe and effective.

Complication rates are reduced for revision adult spine deformity surgery among high-volume hospitals and surgeons

BACKGROUND CONTEXT

Revision adult spinal deformity surgery (RASDS) is a particularly high-risk intervention.

PURPOSE

The aim was to assess complication rates in RASDS by surgeon and hospital operative volume.

STUDY DESIGN/SETTING

This was a retrospective analysis of prospectively collected data.

PATIENT SAMPLE

Based on a Nationwide Inpatient Sample (NIS) database (2001-2010), patients aged older than 21 years (International Classification of Diseases, Ninth Revision, Clinical Modification) with spine arthrodesis for scoliosis were included. For longitudinal analysis, the 2008-2011 New York State Inpatient Database (NY SID) was queried.

OUTCOME MEASURES

The outcome measures included complication rate after RASDS.

METHODS

Cases were identified as primary or revision surgery with or without osteotomy performed. Annual surgeon and hospital volumes were stratified into quartiles via identifier codes. Case complexity was determined using a novel operative complexity index, based on available NIS operative parameters: levels fused, approach, osteotomy, and revision status. The primary end point was morbidity during the hospital stay. New York State Inpatient Database analysis allowed for identification of rate of reoperation for infection or pseudarthrosis/implant failure. One-way analysis of variance was used to assess continuous measures, chi-square for categorical measures.

RESULTS

Of 139,150 adult spinal deformity surgery (ASDS) cases, 4,888 revision with hospital identifiers and 1,978 with surgeon identifiers were identified. Higher-volume surgeons performed more revision cases and cases requiring osteotomy. With increasing hospital volume, complication rate for RASDS decreased (9.7% vs. 12.9% at highest- vs. lowest-volume centers, p< .001). The highest-volume surgeons showed significant decreases in the rate of major complications for RASDS (8.8% vs. 10.7% for lowest-volume surgeons, p< .001). A similar trend was observed for ASDS cases requiring osteotomy. Multiple logistic regression analysis showed that the highest-volume hospitals and surgeons showed a reduced odds ratio for all complications compared with lowest-volume hospitals. For the NY SID, 528 RASDS cases indicated reoperation rates for infection and pseudarthrosis/implant failure after RASDS were increased for the lowest-volume hospitals and surgeons.

CONCLUSIONS

Perioperative complication rate associated with RASDS is lower when patients are treated by high-volume surgeons at high-volume centers. As complex cases requiring osteotomy and combined approaches are more frequent at high-volume centers, an operative complexity index helps predict the likelihood of volume-dependent complication rates. Future interhospital and intersurgeon comparisons should account for these case characteristics so that similar case complexity is compared in these analyses.

High-Volume Hospitals and Surgeons Experience Fewer Early Reoperation Events After Adolescent Idiopathic Scoliosis Surgery

STUDY DESIGN

Retrospective analysis of relevant in-hospital patient records from the New York State Inpatient Database.

OBJECTIVE

We aimed to assess reoperation risk in adolescent idiopathic scoliosis (AIS) by surgeon and hospital operative volume.

SUMMARY OF BACKGROUND DATA

The need for early reoperation can be devastating for patient and family, is a burden to the physician and adds significant cost. Previous studies have shown improved outcomes associated with higher volume surgeons and hospitals, but reoperation events have not yet been explored.

METHODS

The 2008-2011 New York State Inpatient Database was queried using International Classification of Diseases, Ninth Revision, Clinical Modification (ICD-9-CM) codes for adolescent idiopathic scoliosis patients aged 10-21 undergoing spine arthrodesis. Patient identifiers and revisit linkage variables were used to identify reoperation events. Annual surgeon and hospital volumes were stratified into tertiles (low, medium, high) via identifier codes. The relative risk of reoperation after spine arthrodesis was computed based on relevant patient inpatient stays.

RESULTS

Over 2008 to 2011, a total of 3,928 primary fusion operations for AIS were identified. The overall rate of reoperation after spine fusion for idiopathic scoliosis was 7.1%. Low volume surgeons performed less than 6 AIS fusions per year, medium volume surgeons performed less than 43, and high volume surgeons performed from 43 to 228. Reoperation after a primary fusion for adolescent idiopathic scoliosis showed reduced frequency among higher volume surgeons (14.1% for low vs. 5.1% for high, p<0.001, see Table for Hospitals).

CONCLUSIONS

Early reoperation after spine fusion for idiopathic scoliosis is seen more frequently in lower volume institutions and surgeons. Appreciating the resources and limitations at a clinician's institution is important to developing practices to prevent these devastating events. This work also has implications for strategies that aim to direct limited healthcare resources to centers with low complication rates.

Body Mass Index in Adolescent Spinal Deformity: Comparison of Scheuermann's Kyphosis, Adolescent Idiopathic Scoliosis, and Normal Controls

STUDY DESIGN

Prospective, multicenter study of Scheuermann's kyphosis (SK) and adolescent idiopathic scoliosis (AIS) compared to a control group.

OBJECTIVES

Compare body mass index (BMI) and Scoliosis Research Society Questionnaire-22 (SRS-22) scores among two diagnosis and one control group.

SUMMARY OF BACKGROUND DATA

BMI has been reported as increased in SK patients; however, there are few recent data on this subject or comparing SK to AIS.

METHODS

Ninety-two SK patients (37 female, 55 male, average age 16 years), 1,051 AIS patients (814 female, 237 male, average age 15 years), and 380 adolescents without scoliosis (controls) were compared based on age, gender, race, height (m), weight (kg), BMI, and SRS-22 scores. An analysis of variance was used to test differences in BMI and SRS-22 scores between the groups and between males and females. Pearson correlations determined the relationship between AIS T5-T12 kyphosis and BMI, SK max kyphosis and BMI, and to determine the relationship between BMI and SRS-22 scores in each group.

RESULTS

More SK patients were "obese" and "overweight" (28% and 22%) compared to the AIS (6% and 9%) and Control groups (5.8% and 17.9%) (p < .001). More AIS patients were "underweight" (27%, SK: 13%, Control: 12.1%; p < .03). T5-T12 kyphosis was weakly correlated with BMI (r = 0.17), whereas max kyphosis correlated well with BMI (r = 0.39, p < .00). The SK group had significantly lower (worse) SRS-22 scores than AIS patients in the Pain (3.97 vs. 4.10), Self-Image (2.86 vs. 3.35), Mental Health (3.72 vs. 4.02), and Total Score domains (3.62 vs. 3.92, p < .001). Increased pain scores were weakly correlated with decreasing BMI in all three groups.

CONCLUSIONS

SK patients are at increased risk for elevated BMI and worse SRS-22 scores, indicating that they may suffer from delayed diagnosis and increased surgical complications. AIS patients are at increased risk for issues related to low BMI and should also be monitored.

Disease severity and treatment in adolescent idiopathic scoliosis: the impact of race and economic status

BACKGROUND CONTEXT

Ethnic disparities have been documented in the incidence and treatment of many diseases. Additionally, race and socioeconomic status (SES) have been shown to affect disease severity and access to care in the recent orthopedic literature.

PURPOSE

To assess the role, if any, that race, SES, and health insurance type play in disease severity and treatment decisions in patients with adolescent idiopathic scoliosis.

STUDY DESIGN

Retrospective chart review.

PATIENT SAMPLE

Pediatric patients seen in a single surgeon's practice over 6 years (2004-2009).

OUTCOME MEASURES

Treatment modality (observation, bracing, or surgery).

METHODS

Data were obtained from 403 patients seen over 6 years (2004-2009). A patient-reported questionnaire was used to collect race, age, family income, and parent marital status data. Race was self-reported as "Asian," "black or African American," "Hispanic or Latino," "white or Caucasian," or "Other." Socioeconomic status was determined using family income and type of health insurance as indicators. Major curve magnitude and prescribed initial treatment (observation, brace, or surgery) were assessed from physician records. An independent sample t test was used to detect differences in curve magnitude of the different racial groups. A Pearson chi-square analysis was used to detect group differences for curves in surgical patients, defined as curves greater than 40°, and their initial treatment.

RESULTS

Patients self-identified with one of the following racial groups: white (N=219), black (N=86), Hispanic (N=44), Asian (N=37), or Other (N=17). Mean curve magnitude was greater in black than in white patients (33° vs. 28°, p<.05). Black patients were more likely to present with curves in the surgical range (34% vs. 24%, p<.05) and were more likely to have surgery as their initial treatment than white patients (34% vs. 19%, p<.05). Black patients had more limited health care plans and lower incomes compared with whites (p<.001). Patients with higher access insurance plans presented at a younger age than patients with more limited access plans, irrespective of race (13.6 vs. 14.1, p<.05). There was no difference in Cobb angle at presentation by income or type of insurance.

CONCLUSIONS

Curve magnitude and percentage of patients with curves in the surgical range were greater in black than in white patients. There was no difference in age on presentation or treatment offered across all racial groups. Black patients were more likely to have surgery as their initial treatment than white patients. While race did have an impact on disease severity in this single surgeon's practice, SES did not.

Sagittal Spinopelvic Parameters in Scheuermann's Kyphosis: A Preliminary Study

STUDY DESIGN

Retrospective, controlled, clinical study.

OBJECTIVES

To define the average values for sagittal spinopelvic parameters including pelvic incidence (PI), pelvic tilt (PT), and sacral slope (SS) in Scheuermann's kyphosis (SK); evaluate the differences in spinopelvic parameters among patients with SK and unaffected normal controls; and evaluate the correlation of various sagittal spinopelvic parameters to each other in SK and normal controls.

METHODS

Prospectively collected radiographic data from a study on SK were compared with those from previously published series of unaffected patients. Measures were made according to standard, defined measurement methods. Parameters measured included PT, PI, SS, thoracic kyphosis, lumbar lordosis, and radiographic sagittal alignment. Values were compared using independent-samples t test. Pearson correlation coefficient was used to analyze relationships between variables.

RESULTS

A total of 47 patients with SK and 50 control patients, mean age 16.1 and 13.5 years, respectively, were included. In SK, average PI was 42°, average PT was 7°, and average SS was 35°. These values were not different from those of normal controls (PI, 46° [p = .084]; PT, 8° [p = .476]; SS, 37° [p = .162]). Pelvic incidence directly correlated with lordosis in both groups (p < .005). T5-12 kyphosis correlated with lordosis in normal controls (p ≤ .05) but not in the SK group. Kyphosis in SK as quantified by greatest measurable Cobb angle did not correlate with PI or lordosis.

CONCLUSIONS

Sagittal pelvic alignment in patients with SK is not different from that in normal subjects. Furthermore, in SK thoracic kyphosis did not correlate with any distal region of the spine (lumbar or pelvic). Further understanding of the relationship between sagittal spinopelvic alignment in various conditions causing spinal deformity will lead to better treatment of these conditions.

Efficacy of tranexamic acid on surgical bleeding in spine surgery: a meta-analysis

BACKGROUND CONTEXT

Spine surgery is usually associated with large amount of blood loss, necessitating blood transfusions. Blood loss-associated morbidity can be because of direct risks, such as hypotension and organ damage, or as a result of blood transfusions. The antifibrinolytic, tranexamic acid (TXA), is a lysine analog that inhibits activation of plasminogen and has shown to be beneficial in reducing surgical blood loss.

PURPOSE

To consolidate the findings of randomized controlled trials (RCTs) investigating the use of TXA on surgical bleeding in spine surgery.

STUDY DESIGN

A metaanalysis.

STUDY SAMPLE

Randomized controlled trials investigating the effectiveness of intravenous TXA in reducing blood loss in spine surgery, compared with a placebo/no treatment group.

METHODS

MEDLINE, Embase, Cochrane controlled trials register, and Google Scholar were used to identify RCTs published before January 2014 that examined the effectiveness of intravenous TXA on reduction of blood loss and blood transfusions, compared with a placebo/no treatment group in spine surgery. Metaanalysis was performed using RevMan 5. Weighted mean difference with 95% confidence intervals was used to summarize the findings across the trials for continuous outcomes. Dichotomous data were expressed as risk ratios with 95% confidence intervals. A p<.05 was considered statistically significant.

RESULTS

Eleven RCTs were included for TXA (644 total patients). Tranexamic acid reduced intraoperative, postoperative, and total blood loss by an average of 219 mL ([-322, -116], p<.05), 119 mL ([-141, -98], p<.05), and 202 mL ([-299, -105], p<.05), respectively. Tranexamic acid led to a reduction in proportion of patients who received a blood transfusion (risk ratio 0.67 [0.54, 0.83], p<.05) relative to placebo. There was one myocardial infarction (MI) in the TXA group and one deep vein thrombosis (DVT) in placebo.

CONCLUSIONS

Tranexamic acid reduces surgical bleeding and transfusion requirements in patients undergoing spine surgery. Tranexamic acid does not appear to be associated with an increased incidence of pulmonary embolism, DVT, or MI.

Incidence and Risk Factors for Major Surgical Complications in Patients With Complex Spinal Deformity: A Report From an SRS GOP Site

STUDY DESIGN

Retrospective analysis of a prospectively collected single-center database.

OBJECTIVES

To report the incidence of and identify risk factors for perioperative complications in surgically treated pediatric and adult patients with complex spine deformities in an underserved region and Scoliosis Research Society Global Outreach Program site.

SUMMARY OF BACKGROUND DATA

Surgical treatment for complex spinal deformity is challenging and requires a multidisciplinary approach for optimal management. The incidence and risk factors for major perioperative complications in outreach sites with limited resources are unknown.

METHODS

A total of 427 consecutive patients who underwent instrumented spinal fusion for complex spinal deformities were reviewed. Clinical, radiographic, and demographic data were reviewed at preoperative and postoperative time points, and potential risk factors for perioperative complications were assessed. The authors performed multivariate logistic regression analysis (LRA) to determine independent risk factors for postoperative complications and neurological deficits.

RESULTS

Major complications were seen in 85 cases, which consisted of neurologic deficits (n = 27; 17 transient and 10 permanent), wound infections (n = 17), implant-related problems (n = 35), progressive deformity (n = 13), and death (n = 6). Among the possible risk factors, univariate LRA indicated 3-column osteotomies as a risk factor for postoperative major complications and multivariate LRA indicated 3-column osteotomies as an independent risk factor for neurological deficit. Curves 100° and above were at higher risk for complications.

CONCLUSIONS

Postoperative complications were seen in 20% of surgically treated patients with complex spine deformities at a Scoliosis Research Society SRS Global Outreach Program site. Three-column osteotomies were identified as an independent risk factor of both postoperative complications and neurological deficits. The significant observed correlation of 3-column osteotomies and postoperative neurological deficits should serve as a guide for surgeons in the preoperative planning and management of severe spinal deformities, especially in locations with limited resources. Patients undergoing correction of large curves may also have a higher complication rate.

Surgical Risk Stratification Based on Preoperative Risk Factors in Severe Pediatric Spinal Deformity Surgery

STUDY DESIGN

Retrospective review.

OBJECTIVE

The purpose of this study is to review the postoperative complications in pediatric patients undergoing spine surgery and to establish a preoperative classification that stratifies surgical risk and case difficulty.

SUMMARY OF BACKGROUND DATA

Pediatric spinal deformity (PSD) surgery can be challenging technically as well as economically. Often, a multidisciplinary approach to managing these patients is necessary. In an environment where resources are limited, such as in global outreach efforts, a method for stratifying PSD surgical cases can be useful for allocating appropriate resources and assigning appropriate skill sets in order to optimize patient outcomes and to streamline efforts.

MATERIALS AND METHODS

A total of 145 consecutive PSD patients who underwent instrumented spinal fusion were reviewed. Radiographic measurements and demographic data were reviewed. A classification was established based on the curve magnitude, etiology, ASA grade, number of levels fused, the preoperative neurologic status, body mass index and type of osteotomies. Multiple regression analysis (MRA) and logistic regression analysis (LRA) were applied to indicate risk factors for complications.

RESULTS

The average age was 14.3 years (10-20 years). The etiology was idiopathic scoliosis (n = 71), congenital scoliosis (n = 38), infectious (n = 11), and others. 23 patients had neurologic deficits preoperatively. Twenty-three patients had a posterior vertebral column resection. Patients were classified as Level 1 (n = 5), Level 2 (n = 19), Level 3 (n = 24), Level 4 (n = 58), and Level 5 (n = 39). Intraoperative neuro-monitoring changes were observed in 46 cases. Major complications were seen in 45 cases. A major complication consisted of implant related (n = 13), deep wound infection (n = 8), neurologic deficit (n = 7), death (n = 2), and others (n = 9). MRA demonstrated a significant correlation between classified level and %EBL/TBV, operative time, and complication rate. The risk level predicted the occurrence of general (odds ratio [OR] = 1.54; 95% confidence interval [CI] = 1.08-2.21; p = .019) and neurologic (OR = 3.34; 95% CI = 1.06-17.70; p = .036) complications. Osteotomy and resection procedures were independent predictors for postoperative neurologic complications (OR = 1.7, 95% CI = 1.11-2.85; p = .015).

CONCLUSION

Corrective spine surgery for complex pediatric deformity is challenging and carries a substantial risk. No single parameter appears to independently predict postoperative complications. However, when all risk factors are considered, there is a trend toward increased intraoperative electromonitoring change and postoperative neurologic risk with the higher level score in our classification. The newly established surgical risk stratification based on patient-specific clinical and radiographic factors can guide surgeons in their preoperative planning and surgical management of severe spine deformity in order to achieve optimal outcomes.

The effect of surgeon experience on outcomes of surgery for adolescent idiopathic scoliosis

BACKGROUND

Single-surgeon series investigating the learning curve involved in surgery for spinal deformity may be confounded by changes in technology and techniques. Our objective with this multicenter, prospective study was to present a cross-sectional analysis of the impact of surgeon experience on surgery for adolescent idiopathic scoliosis.

METHODS

All posterior-only surgical procedures for adolescent idiopathic scoliosis performed in the 2007 to 2008 academic year, with a minimum of two years of patient follow-up, were included. Two groups were created on the basis of surgeon experience: a young surgeons' group, which included patients of surgeons with less than five years of experience, and an experienced surgeons' group, which included patients of surgeons with five or more years of experience.

RESULTS

Nine surgeons (four young and five experienced) operated on a total of one hundred and sixty-five patients with adolescent idiopathic scoliosis. The surgeons' experience ranged from less than one year to thirty-six years in practice. The two groups had similar preoperative curve-magnitude measurements, SRS-22 (Scoliosis Research Society-22) scores, and distribution by Lenke curve type. There were significant operative and postoperative differences. The young surgeons fused an average of 1.2 levels more than the experienced surgeons (p = 0.045). The mean intraoperative estimated blood loss (EBL) of the young surgeons' group was more than twice that of the experienced surgeons' group (2042 mL compared with 1013 mL; p < 0.001). The duration of surgery was 458 minutes for the young surgeons compared with 265 minutes for the experienced surgeons (p < 0.001). The overall SRS-22 scores were significantly worse in the young surgeons' group (a mean of 4.1 compared with 4.5; p = 0.001). The difference between groups was also significant for the domains of pain (p = 0.016), self-image (p = 0.008), and function (p < 0.001). Complication rates did not differ significantly between the groups.

CONCLUSIONS

Operative results and health-related quality of life following surgery for adolescent idiopathic scoliosis were significantly and positively correlated with surgeon experience.

LEVEL OF EVIDENCE

Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.

The relative efficacy of antifibrinolytics in adolescent idiopathic scoliosis: a prospective randomized trial

BACKGROUND

Antifibrinolytics can reduce intraoperative blood loss. The primary aim of this study was to determine the efficacy of intraoperative tranexamic acid, epsilon-aminocaproic acid, and placebo at reducing perioperative blood loss and the transfusion rate in patients with adolescent idiopathic scoliosis undergoing posterior spinal arthrodesis.

METHODS

This is a prospective, randomized, double-blind comparison of tranexamic acid, epsilon-aminocaproic acid, and placebo used intraoperatively in patients with adolescent idiopathic scoliosis. One hundred and twenty-five patients with adolescent idiopathic scoliosis were randomly assigned to the tranexamic acid, epsilon-aminocaproic acid, or control groups. Parameters recorded included estimated blood loss, hematocrit, blood product usage, drain output, and total blood losses. The primary outcomes were intraoperative blood loss and postoperative drainage. Secondary outcomes were transfusion requirements and hematocrit changes both intraoperatively and postoperatively.

RESULTS

One hundred and twenty-five patients (ninety-seven female and twenty-eight male, with a mean age of fifteen years) were randomized to receive tranexamic acid (thirty-six patients), epsilon-aminocaproic acid (forty-two patients), or saline solution (forty-seven patients). The groups were similar at baseline, with one exception: the saline solution group had a higher estimated blood volume at baseline than the tranexamic acid group. Both tranexamic acid and epsilon-aminocaproic acid reduced the estimated blood loss per degree and estimated blood loss per pedicle screw. Epsilon-aminocaproic acid, but not tranexamic acid, reduced estimated blood loss and estimated blood loss per level. Tranexamic acid also reduced total blood losses compared with epsilon-aminocaproic acid or saline solution. In an analysis controlling for level, degree, and number of anchors, tranexamic acid reduced drain output and total blood losses. Tranexamic acid or epsilon-aminocaproic acid had a smaller decrease in hematocrit postoperatively. In an analysis controlling for the mean arterial pressure during surgical exposure, tranexamic acid reduced estimated blood loss and total blood losses. Overall, antifibrinolytics (tranexamic acid or epsilon-aminocaproic acid) reduced estimated blood loss, total blood losses, and the decline in hematocrit postoperatively compared with saline solution. There was no difference among the groups with respect to the transfusion rate, duration of surgery, levels fused, or pedicle screws placed.

CONCLUSIONS

Tranexamic acid and epsilon-aminocaproic acid reduced operative blood loss but not transfusion rate. Tranexamic acid is more effective at reducing postoperative drainage and total blood losses compared with epsilon-aminocaproic acid. Maintenance of the mean arterial pressure at &lt;75 mm Hg during surgical exposure appears to be critical for maximizing antifibrinolytic benefit.

LEVEL OF EVIDENCE

Therapeutic Level I. See Instructions for Authors for a complete description of levels of evidence.