Novel posterior apical short-segment correction of adolescent idiopathic scoliosis: a prospective multicentre study

Oral Presentations / The Spine Journal 16 (2016) S97–S99 RESULTS: 106 cases included, 94 female. 78 Lenke 1. Mean age 14 years (9–26). Mean main thoracic (MT)2 Cobb angle 63° corrected to 22° (66%). No significant correlations were present between metal density and (1) coronal curve correction rates of the MT (r=0.13, p=.19); (2) lumbar curve frontal correction (r=−0.15 p=.12); (3) FBCI in MT curve (r=−0.10 p=.32); (4) FBCI in lumbar curve (r=0.11, p=.28). Metal density was not correlated with change in thoracic kyphosis (r=0.22 p=.04) or lumbosacral lordosis (r=0.27 p=.01). Longer fusions were associated with greater loss of thoracic kyphosis (r=−0.31 p=.003). Groups differing by preoperative curve size or stiffness had comparable corrections with similar metal density. The pedicle screw cost represented 21%–29% of overall cost of inpatient treatment depending on metal density. CONCLUSIONS: Metal density affects cost but not the coronal and sagittal correction of thoracic AIS. Both larger and stiffer curves do not necessitate high metal density. CONFLICTS OF INTEREST: No conflicts of interest. FUNDING SOURCES: No funding obtained. http://dx.doi.org/10.1016/j.spinee.2015.12.039 A preoperative radiological measurement that can predict poor results after a selective thoracic fusion (STF) in patients with adolescent idiopathic scoliosis (AIS) Amy Lambert, Ashley Cole, Lee Breakwell, A.L. Rex Michael; Sheffield Children’s Hospital, Sheffield BACKGROUND CONTEXT: Criteria have been suggested for the correct determination of the lowest instrumented vertebra (LIV) in selective thoracic fusion (STF) to decrease the likelihood of postoperative decompensation, progression of the unfused lumbar curve and hence the need for revision surgery. However, there is no standardised preoperative measurement currently implemented. PURPOSE: To identify a preoperative radiographic measurement able to predict a poor surgical outcome when using modern surgical techniques. STUDY DESIGN/SETTING: A retrospective radiological analysis of a cohort of adolescent idiopathic scoliosis (AIS) patients. PATIENT SAMPLE: 67 patients, 89.6% female, 10.4% male. Mean age at first surgery is 13.4 years ±1.6, range 9–16 years. OUTCOME MEASURES: Radiological measurement from preoperative, 8-week and 1-year postoperative postero-anterior (PA) radiographs. METHODS: Patient inclusion criteria ensured all patients had an STF for their AIS, and a minimum of preoperative and 1-year follow up radiographs. All patients had a Lenke type 1B, 1C or 3C curve before surgery. The data were checked for normality and equal variances, and the significance level was set at p<.05. Intra-individual measurement reproducibility was calculated on preoperative and 1-year postoperative PA radiograph measurements for eight of the patients included in the study. Group “R” of nine patients were offered extension of their STF into the lumbar spine for a perceived poor radiological/clinical result (four patients had extension). 58 had a good radiological/clinical outcome (group NR). RESULTS: The most significant preoperative radiographic measurement that predicted a poor surgical outcome was vertebral displacement of the LIV from the central sacral vertical line (CSVL, p=.001). For patients offered fusion extension, the mean displacement for the LIV was significantly further towards the convexity of the main thoracic curve (R=17.9 mm±12.8), compared to those patients not offered revision surgery (group NR) where the mean displacement for the LIV was close to the CSVL (NR=2.3 mm±13.1). Similarly, LIV tilt (R=33o, NR=26o, p=.03). CONCLUSIONS: In general, an STF has a very good radiological outcome after surgery. The results suggest that the LIV in patients with a poor radiological outcome can be incorrectly determined using modern surgical techniques. If the proposed LIV is more than 10 mm to the thoracic convexity away from the CSVL, then 30% (7 of 23) were considered to have a poor radiological/ clinical outcome and were offered extension of the fusion into the lumbar spine. This is compared to 5% (2/44) with LIV displacement less than 10 mm. In this circumstance, consideration should be given to extending the fusion one level caudal.

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CONFLICTS OF INTEREST: No conflicts of interest. FUNDING SOURCES: No funding obtained. http://dx.doi.org/10.1016/j.spinee.2015.12.040

Novel posterior apical short-segment correction of adolescent idiopathic scoliosis: a prospective multicentre study Ľuboš Rehák, Martin Repko, Michael Grevitt, Ufuk Aydinli, Allen Carl, Behrooz A. Akbarnia, Colin Nnadi, Steven Seme, Dennis G. Crandall; Comenius University, MS, I-st OTD & UHB, Ružinovska 6, 82606 Bratislava, Slovakia BACKGROUND CONTEXT: Posterior instrumentation with fusion is routinely utilised to treat patients with adolescent idiopathic scoliosis (AIS). The implant density and levels requiring fusion remain controversial. The technique in this study provides an alternative to conventional fusion constructs by utilising less exposure, lower implant density and fewer levels of fusion. PURPOSE: To report 1-year performance and safety outcomes of a new posterior technique for surgical treatment of AIS employing fewer instrumented vertebrae and fewer fused spinal segments. STUDY DESIGN/SETTING: Prospective, non-randomised, multicentre study. PATIENT SAMPLE: 21 female patients with Lenke 1A/1B curves. OUTCOME MEASURES: Thoracic kyphosis, Cobb angle, SRS22 score, revision rate. METHODS: A novel pedicle screw and rod-connection system applied translational and derotational forces over a short apical region. The short apical region was prepared for fusion while proximal and distal vertebral segments were not prepared for fusion. Clinical and radiographic data were collected preoperatively, at surgery/discharge, and at 6 and 12 months after surgery. RESULTS: Twenty-one female patients, mean age of 14.2 years (11–17 years) with Lenke 1A/1B curves were enrolled. Average levels stabilised for fusion were 5.0 levels (4–6 levels). Average main thoracic Cobb angle improved from 56.1° (42–78°) to 20.8° (9–36°), resulting in a 62.2% improvement at 12 months (p<.001). The average preoperative thoracic kyphosis (T5– T12) was 16.0° (2–26°), which improved to 23.7° (14–43°) at 12 months. Mean thoracic rib prominence as measured by scoliometer decreased from 16.7° (7–24°) to 10.4° (5–17°) at 12 months. SRS22r total score improved from 3.7 (1.7–4.6) to 4.1 (2.7–5.0) at 12 months (p=.024). There were no rod, screw or connector failures at 12 months post-op. One unplanned revision was performed to remove an asymptomatic misplaced screw identified by protocol-required postoperative computerised tomography (CT) assessment. CONCLUSIONS: Through 1 year, this new technique achieved and maintained similar AIS correction to current posterior fusion techniques while limiting exposure and arthrodesis of motion segments. This technique was safe and successful at limiting implant density and levels intended for fusion. CONFLICTS OF INTEREST: L Rehák—DePuy Synthes Spine (A,B), Kspine (A); M Repko—Kspine (A); M Grevitt—DePuy Synthes Spine (A,B), Medtronic (A); U Aydinli—Kspine (A); A Carl—K2M (E), Kspine (B,E,G); BA Akbarnia—Alphatec (C), DePuy Synthes Spine (A,G), Ellipse Technology (B,G), K2M (B,G), Kspine (B,E,G), Nuvasive (A,B,C,G); C Nnadi—No conflicts; S Seme—Kspine (F,G); D Crandall—Ellipse Technology (B), Kspine (B,E,G), Medtronic (B,G), Spinewave (B), Stryker (B,D), Zyga (B). (A) Grants/Research Support; (B) Consultant; (C) Stock/ Shareholder; (D) Speaker’s Bureau; (E) Advisory Board or Panel; (F) Salary, Contractual Services; (G) Other Financial or Material Support (royalties, patents, stock options, etc.). FUNDING SOURCES: Corporate/Industry funds were received in support of this work from Kspine, Inc. One or more of the author(s) has/have received or will receive benefits for personal or professional use from a commercial party related directly or indirectly to the subject of this manuscript (eg, honoraria, gifts, consultancies, royalties, stocks, stock options, decision-making position). http://dx.doi.org/10.1016/j.spinee.2015.12.041