Prior Spinal Fusion Research Articles

Can titanium surface technology reduce cost for biologics in anterior lumbar interbody fusion?

Advances in surface architecture and technology have made interbody fusion devices more bioactive, with the hope of facilitating the fusion process more successfully. The advent of these increasingly bioactive implants may reduce reliance on more expensive biologics that have previously been used to achieve high fusion rates. A retrospective review of prospectively collected data (August 2018-December 2019) was conducted of consecutively performed anterior lumbar interbody fusions in which an acid-etched, nanosurface-modulated, titanium interbody device packed only with corticocancellous allograft chips and local blood was used. Minimum follow-up was 1 year, and inclusion required available imaging and outcome metrics preoperatively and at 1 year. Fusion and subsidence were assessed via CT scans and/or dynamic radiographs. Health-related quality-of-life measures (Oswestry Disability Index [ODI], visual analog scale [VAS] back/leg) were collected pre- and postoperatively. In total, 55 patients met inclusion criteria (1 year of follow-up, available imaging, and outcome metrics). A total of 69 lumbar levels were treated in these 55 patients. The mean age was 67 ± 12.1 years, with 47% female patients. Roughly one-third (35%) had previous spine surgery, and approximately one-tenth (9.1%) had prior spinal fusion. A total of 20.6% were treated at multiple levels (mean levels per patient 1.2, minimum 1, maximum 3). The mean preoperative patient-reported outcomes were as follows: ODI 39.71 ± 18.15, VAS back 6.49 ± 2.19, and VAS leg 5.41 ± 2.71. One year after surgery, the mean improvements in patient-reported outcomes (vs preoperative scores) were as follows: ODI -22.9 ± 13.08 (p < 0.001), VAS back -3.75 ± 2.03 (p < 0.001), VAS leg -3.73 ± 2.32 (p < 0.001). All levels achieved fusion at 1 year postoperatively based on CT scans (65/69 levels) or dynamic radiographs (4/69 levels, change in score < 5% on flexion-extension radiographs). Four of the 65 levels were assigned to the grade 3 category according to a CT-based grading system, meaning cranial and caudal endplate bone apposition to the implant on both surfaces with no clear intervertebral bone connection through or around the implant. Sixty-one of 65 were found to have contiguous intervertebral bone bridging and thus were assigned to grade 1 (n = 54) or grade 2 (n = 7). Low-grade graft subsidence (Marchi grade 0 or I) occurred in 9 levels (13.0%) and high-grade subsidence (Marchi grade II or III) in 4 levels (5.8%). No patients required reoperation at the level of anterior lumbar interbody fusion and no radiographic or clinical evidence of pedicle screw loosening or failure was observed. The combination of advances in materials science and surface technology as demonstrated with a nanotechnology titanium cage resulted in the ability to obtain lumbar interbody fusion with allograft chips and local blood alone. Achieving high fusion rates with low-cost biologics/allograft provides for an attractive pathway toward reducing the cost of reconstructive spine care, and a potential incremental benefit for healthcare economics.

Impact of prior spinal fusion surgery on complications and functional outcomes following total hip arthroplasty: an updated systematic review and meta-analysis.

This study aimed to compare the complication rates and functional outcomes between patients with and without a history of spinal fusion undergoing THA. A systematic search was conducted across PubMed, EMBASE, Scopus, and Cochrane databases. Studies that compared adults with and without a history of spinal fusion after primary THA were included. The methodological quality of the studies was evaluated using MINORS criteria. Meta-analyses were performed utilizing mean differences (MD), standardized mean differences (SMD), and odds ratios (OR), along with 95% confidence intervals (CI). Seventeen studies involving 1,789,356 patients (31,786 in the SF group and 1,757,570 in the Non-SF group) were analyzed. The spinal fusion group exhibited significantly higher rates of dislocation (OR 2.50, 95% CI 1.78-3.52), periprosthetic fracture (OR 1.96, 95% CI 1.39-2.77), overall complications (OR 1.73, 95% CI 1.10-2.71), and revision rates (OR 1.86, 95% CI 1.74-1.99). Furthermore, within the first three months, there was an increased risk of dislocation (OR 4.38, 95% CI 1.36-14.14) and revisions (OR 3.87, 95% CI 1.63-9.18). Longer spinal fusions were significantly associated with a higher risk of dislocations (OR 0.62, 95% CI 0.53-0.71). Additionally, prior spinal fusion was linked to higher levels of pain (SMD 0.11, 95% CI 0.02-0.19) and poorer functional outcomes (MD - 0.09, 95% CI - 0.18 to - 0.00). Patients with a history of spinal fusion undergoing THA exhibit increased complication rates, higher levels of pain, and greater functional limitations than those without prior fusion. These findings have significant clinical implications for optimizing perioperative care in high-risk patient populations.

Impact of prior spinal fusion surgery on complications and functional outcomes following total hip arthroplasty: An updated systematic review and meta-analysis

Impact of prior spinal fusion surgery on complications and functional outcomes following total hip arthroplasty: An updated systematic review and meta-analysis

Comparison of complications, revisions, spinopelvic parameters, and health-related quality of life after posterior spinal fusion using multiple-rod constructs or two-rod constructs for adult spinal deformity: a systematic review and meta-analysis.

The incidence of mechanical complications is high in patients undergoing posterior spinal fusion (PSF) for adult spinal deformity (ASD), especially for cases with severe sagittal malalignment or a prior spinal fusion requiring three-column osteotomy (3-CO) or spinopelvic fixation (SPF). The purpose of this systematic review and meta-analysis was to compare the complications, revisions, radiographic spinopelvic parameters, health-related quality of life (HRQoL), and surgical data of PSF using multiple-rod constructs to those of two-rod constructs for the treatment of ASD. A comprehensive literature search was performed for relevant studies in PubMed, EMBASE, Web of Science, and the Cochrane Library. Complications, revisions, spinopelvic parameters, HRQoL, and surgical date were compared between patients with ASD who underwent PSF using multiple-rod constructs (multi-rod group) and two-rod constructs (two-rod group). Ten studies, comprising 797 patients with ASD (399 in the multi-rod group and 398 in the two-rod group), were included. All these studies were retrospective cohort studies. There were no significant differences in the surgical, wound-related, and systemic complications between the groups. In the multi-rod group, we noted a significantly lower incidence of rod fracture (RR, 0.43; 95% CI 0.33 to 0.57, P < 0.01), pseudoarthrosis (RR, 0.38; 95% CI 0.28 to 0.53, P < 0.01), and revisions (RR, 0.44; 95% CI 0.33 to 0.58, P < 0.01); a superior restoration of PI-LL (WMD, 3.96; 95% CI 1.03 to 6.88, P < 0.01) and SVA (WMD, 31.53; 95% CI 21.16 to 41.90, P < 0.01); a better improvement of ODI score (WMD, 6.82; 95% CI 2.33 to 11.31, P < 0.01), SRS-22 total score (WMD, 0.44; 95% CI 0.06 to 0.83, P = 0.02), and VAS-BP score (WMD, 1.02; 95% CI 0.31 to 1.73, P < 0.01). Compared with the two-rod constructs, PSF using multiple-rod constructs was associated with a lower incidence of mechanical complications, a lower revision rate, a superior restoration of sagittal alignment, and a better improvement of HRQoL, without increasing surgical invasiveness. Multiple-rod constructs should be routinely considered to for ASD patients, especially for cases with severe sagittal malalignment or a prior spinal fusion requiring 3-CO or SPF.

No Difference in Two-Year Revisions Between Hybrid Fusion and Two-Level Anterior Discectomy and Fusion: A National Database Study.

Retrospective Cohort. This study utilized a large national database to compare two-year revision rates, in addition to complications and costs, of hybrid surgery (HS) compared to two-level anterior cervical discectomy and fusion (ACDF). This study used the PearlDiver Mariner dataset selecting for patients aged 18 and older who had at least 90-day active longitudinal follow-up who underwent two-level ACDF or two-level Hybrid surgery (single level ACDF and single level CDA). Patients with prior spinal trauma, infection, cancer, or posterior fusion were excluded. Primary outcomes measures were 90-day major and minor medical complications, ED visits, readmissions, as well as two-year revisions. Patients were also assessed for postoperative dysphagia, incidental durotomy, vascular injury, 90-day surgical site, and implant complications. Additionally, hospitalization and postoperative costs were evaluated. There were 4570 two-level ACDF surgeries and 888 hybrid surgeries. After matching the cohorts, no statistical differences in demographics were found. There were no differences in reoperation rates at all measured time points nor 2-year complications. HS had a lower incidence of major (1.6% vs 3.1%, P = .003) and minor complications (3.0% vs 4.6%, P = .009) than ACDF. 90-day readmission was lower in the HS cohort (2.8% vs 4.2%), P = .024. HS was associated with reduced hospitalization costs -$2614 (-$3916 to -$904, P < .001). 3516 patients had ACDF, and 699 had HS with at least 2years of follow-up. Hybrid surgery is a safe and effective surgical treatment for cervical disease in appropriately selected patients.

Cardiac Complications After 3-Column Osteotomy for Adult Spinal Deformity Patients With Formal Cardiac Clearance: Identifying Key Risk Factors and Threshold Cutoffs Via Recursive Partitioning Analysis.

Despite formal cardiac clearance, a subset of 3-column osteotomy (3CO) patients still experience cardiac complications (CCs). To define the incidence and risk factors for CC in 3CO patients who had formal cardiac clearance and assess the utility of the Revised Cardiac Risk Index (RCRI) and preoperative metabolic equivalent (MET) functional ability in predicting perioperative CC. Patients with adult spinal deformity (ASD) who underwent 3CO deformity correction from 2006 to 2019 were retrospectively reviewed. Multivariate and recursive partitioning analyses were performed to assess risk factors. A total of 390 patients with ASD were included. The mean age was 64.6 years, and 60.3% were female. The CC rate was 9.7%. Patients with CCs were older ( P &lt; .001), had an increased history of heart disease ( P = .001), and higher blood loss ( P = .045). RCRI score ( P = .646) or MET functional ability ( P = .493) were not associated with CC. On multivariate analysis, age ( P &lt; .001), blood loss ( P = .008), and prior spinal fusion ( P = .025) were independent risk factors for CC. Patients age older than 81 years had a significantly higher CC rate than those younger than 81 years. In patients age 81 years and younger, if blood loss was &gt;3900 mL, CC rate was significantly higher. Among patients age 81 years and younger and with &gt;3900 mL blood loss, CC rate is significantly higher in patients with ejection fraction (EF) ≤54.5%. RCRI and MET functional ability are limited risk assessment tools in ASD 3CO patients with formal cardiac clearance. Patients older than 81 years are at high risk for CC. In younger patients, cardiac EF and blood loss are significant components to risk stratify for CC.

Nusinersen for Patients With Spinal Muscular Atrophy: 1415 Doses via an Interdisciplinary Institutional Approach

BackgroundSpinal deformity and prior spinal fusion pose technical challenges to lumbar puncture (LP) for nusinersen administration for patients with spinal muscular atrophy (SMA). In this retrospective study over two study phases, we evaluated (1) factors associated with difficult LP or unscheduled requirement for image guidance and (2) effectiveness of a triage pathway for selective use of image guidance and nonstandard techniques, particularly for patients with spinal instrumentation/fusion to the sacrum. MethodsWith institutional review board approval, electronic health records, imaging, and administrative databases were analyzed for patients receiving nusinersen from January 2012 through September 2021. Descriptive statistics and univariate analyses were used. ResultsFrom January 2012 to March 2018 (phase 1), among 82 patients with SMA, 461 of 464 (99.4%) LP attempts were successful. Univariate analyses associated difficulty with prior spinal instrumentation, higher body mass index, and severity of the spinal deformity. Based on this experience, starting in April 2018 (phase 2), 125 patients were triaged selectively for ultrasound, fluoroscopy, or Dyna computed tomography. Patients with spinal instrumentation/fusion to the sacrum were treated primarily via intrathecal ports (137 doses) or transforaminal LP (55 doses). From April 2018 through September 2021, 704 of 709 (99.3%) LPs were successful. In total from January 2012 to September 2021, 1415 doses were administered. Over 50% of LPs were performed by neurology nurse practitioners without image guidance. Safety outcomes were excellent. ConclusionsA stratified approach resulted in successful intrathecal nusinersen delivery and efficient resource allocation for patients with SMA, with or without complex spinal anatomy.

Lumbar Spine Fusion and Symptoms of Leg Length Discrepancy After Hip Arthroplasty

BackgroundHip length discrepancy (HLD) is common after total hip arthroplasty (THA); however, the effect of spinal fusion on perceived leg length discrepancy (LLD) symptoms after THA has not been examined. This study tested the hypothesis that LLD symptoms are increased in patients who underwent lumbar spinal fusion and THA, compared with patients with THA only. MethodsThis retrospective cohort study included 67 patients who underwent lumbar spinal fusion and THA, along with 78 matched control patients who underwent THA only. Hip and spine measurements were taken on postoperative, standing anterior-posterior pelvic, lateral lumbar, and anterior-posterior lumbar spinal radiographs. Perceived LLD symptoms were assessed via telephone survey. ResultsBetween the spinal fusion and control groups, there was no significant difference in HLD (M = 7.10 mm, SE = 0.70 and M = 5.60 mm, SE = 0.49) (P = .403). The spinal fusion patients reported more frequently noticing a difference in the length of their legs than the control group (P = .046) and reported limping “all the time” compared with the control group (P = .001). Among all patients with an HLD ≤10 mm, those in the spinal fusion group reported limping at a higher frequency than patients in the control group (P = .008). Patients in the spinal fusion group were also more likely to report worsened back pain after THA (P = .011) than the control group. ConclusionFrequencies of a perceived LLD, limping, and worsened back pain after THA were increased in patients with THA and a spinal fusion compared with patients who had THA only, even in a population with HLD traditionally considered to be subclinical. The results indicate that in patients with prior spinal fusion, precautions should be taken to avoid even minor LLD in the setting of THA.

Prevalence of Lumbosacral Transitional Vertebrae in Patients With Symptomatic Femoroacetabular Impingement Requiring Hip Arthroscopy

The primary aim of this study was to determine the prevalence of lumbosacral transitional vertebrae (LSTVs) in patients with symptomatic femoroacetabular impingement (FAI) requiring hip arthroscopy. The secondary aim was to determine whether there is an association between LSTV anatomy and patient-reported outcomes. This retrospective study included patients aged 18 to 45 years with symptomatic FAI who underwent arthroscopy between March 2010 and March 2016 and had anteroposterior pelvic radiographs. The exclusion criteria included lack of an FAI diagnosis, hip osteoarthritis (Tönnis grade ≥ 2), prior spinal fusion surgery, prior total hip arthroplasty, indications for total hip arthroplasty, and revision surgery on the affected hip. All radiographs were assessed by an interventional spine and sports fellow. The primary outcome was the prevalence of LSTVs, classified using the criteria of Castellvi etal. Secondary outcomes included the modified Harris Hip Score, Hip Outcome Score, and International Hip Outcome Tool 33 score. A total of 1,880 patients were included. Review of the patients' radiographs yielded 262 LSTVs, for an overall prevalence of 13.9% (type IA in 104 [5.5%], type IB in 53 [2.8%], type IIA in 60 [3.2%], type IIB in 25 [1.3%], type IIIA in 8 [0.4%], type IIIB in 0 [0%], and type IV in 12 [0.64%]). The prevalence of type II, III, and IV LSTVs was 5.6% (n=105). Unilateral LSTV sidedness did not correlate with symptom laterality (κ= 0.07). There were no differences in patient-reported outcomes between patients with LSTV anatomy and those without it. In this large cohort of 1,880 patients with symptomatic FAI, the prevalence of LSTVs was 13.9%. There was no correlation between sidedness of unilateral LSTVs and the symptomatic hip. Furthermore, there was no association between LSTV anatomy and patient-reported outcomes. The prevalence of LSTVs in this cohort was similar to the prevalence rates previously reported in patients with low-back pain. Level IV, case series.

231. The use of fusion mass screws in revision spinal deformity surgery: preliminary results and analysis

BACKGROUND CONTEXT Revision spinal deformity surgery in a previously fused spine often presents a number of challenges. Conventional landmarks for pedicle screw placement may be obscured or nonexistent, increasing the potential for inadequate fixation and spinal cord or nerve root injury. In these situations, screws through an existing fusion mass in patients with prior spinal fusion represent an alternative to pedicle screw fixation. This may provide stable fixation while reducing the risk of complications related to pedicle screw placement. PURPOSE To further elucidate the safety and efficacy of fusion mass screws (FMS) in revision spinal deformity surgery as an alternative and/or adjunct to pedicle screw fixation. STUDY DESIGN/SETTING Case series. PATIENT SAMPLE Adult patients undergoing revision spinal deformity surgery. OUTCOME MEASURES BMD of fusion mass, AP thickness of fusion mass, presence and degree of canal breach, screw loosening, screw failure, pseudarthrosis. METHODS Fourteen freehand FMSs were placed in six cases of revision adult spinal deformity surgery between 2016 and 2018. All screws were 5 mm in diameter. FMSs were used to save distal levels from fusion, assist in closing a three-column osteotomy, stabilize a Charcot spine with severe degeneration, and achieve fixation in the setting of pedicular dysplasia associated with NF-1. The bone mineral density (BMD) and thickness of the posterolateral fusion mass was assessed on preoperative CT scans at the level of each planned FMS when available. The accuracy of FMS placement and presence of pseudarthrosis were evaluated on postoperative CT scans. RESULTS Fourteen freehand FMSs were placed in six cases of adult spinal deformity. In all cases, FMSs were combined with pedicle screws, at times at the same levels. There were no neurophysiologic alerts observed during FMS placement and no neurologic deficits or complications postoperatively. On postoperative CT, 1/14 screws had a low-grade breach into the canal ( CONCLUSIONS A mature fusion mass consists of a dense, vacant surface for screw fixation. FMSs may be used to achieve stable fixation in revision spinal deformity cases when pedicles are dysplastic and/or normal anatomical landmarks are obscured by an extensive fusion mass. Additionally, FMSs may provide an additional anchor at a level where two pedicle screws are already placed to increase the strength and rigidity of the construct, assist in osteotomy closure, and potentially shorten the construct. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.

Dual-Mobility Constructs in Primary Total Hip Arthroplasty in High-Risk Patients With Spinal Fusions: Our Institutional Experience

BackgroundPrior spinal fusion significantly increases the risk of dislocation in patients after total hip arthroplasty (THA). Owing to these high risks, surgeons may use dual-mobility (DM) constructs in these patients to optimize hip stability. However, there is a paucity of data on the outcomes of DM constructs in patients who underwent prior spinal fusions. MethodsWe retrospectively identified 80 patients (86 THAs) who underwent a spinal arthrodesis and a subsequent posterior approach THA with a DM construct. The median number of levels fused was 4, with 59 (74%) patients having 2 or more levels fused; in addition, 50 (63%) patients were fused to the sacrum. Ninety percent and 55% of THAs were within the Lewinnek safe zone for inclination and anteversion, respectively. Patients were evaluated for any episode of hip instability, complications, and patient reported outcome measures. ResultsAt 3-year mean follow-up, no patients sustained a postoperative dislocation or intraprosthetic dislocation (0%). Overall, there were 6 (7.5%) complications during the study period leading to reoperation in 3 (4%) patients, none related to the acetabular component or instability. Hip Injury and Osteoarthritis Outcome Score, Joint Replacement scores significantly improved from a mean of 50 preoperatively to 87 postoperatively (P < .001), and the Veterans Rand 12 Item Health Survey physical score improved from a mean of 31 preoperatively to 44 postoperatively (P < .001). ConclusionIn a high-risk series of patients who underwent prior spinal fusion, posterolateral primary THA with a DM construct demonstrated no dislocations at mean 3-year follow-up. Although these early data are clearly encouraging, more patients with longer term follow-up are needed.

Outcomes following primary total hip arthroplasty with pre-existing spinal fusion surgery.

There is inconsistent evidence on whether prior spinal fusion surgery adversely impacts outcomes following total hip arthroplasty (THA). We conducted a systematic review and meta-analysis to assess the association between pre-existing spinal fusion surgery and the rate of complications following primary THA. We searched MEDLINE, Embase, Web of Science, and Cochrane Library up to October 2019 for randomized controlled trials (RCTs) and observational studies comparing outcomes of dislocation, revision, or reasons for revision in patients following primary THA with or without pre-existing spinal fusion surgery. Furthermore, we compared short (two or less levels) or long (three or more levels) spinal fusions to no fusion. Summary measures of association were relative risks (RRs) (with 95% confidence intervals (CIs)). We identified ten articles corresponding to nine unique observational studies comprising of 1,992,366 primary THAs. No RCTs were identified. There were 32,945 cases of spinal fusion and 1,752,362 non-cases. Comparing prior spinal fusion versus no spinal fusion in primary THA, RRs (95% CI) for dislocation was 2.23 (1.81 to 2.74; seven studies), revision 2.14 (1.63 to 2.83; five studies), periprosthetic joint infection 1.71 (1.53 to 1.92; four studies), periprosthetic fracture 1.52 (1.28 to 1.81; three studies), aseptic loosening 1.76 (1.54 to 2.01; three studies), and any complications 2.82 (1.37 to 5.80; three studies) were identified. Both short and long spinal fusions, when compared with no fusion, were associated dislocation, revision, or reasons for revision. Patients with prior spinal fusion are at risk of adverse events following primary THA. Measures that reduce the risk of these complications should be considered in this high-risk population when undergoing primary THA. These patients should also be counselled appropriately around their risks of undergoing THA. Cite this article: Bone Joint J 2020;102-B(6):664-670.

Association of Cost Savings and Surgical Quality With Single-Vendor Procurement for Spinal Implants

Significant cost savings can be achieved from consolidating purchases of spinal implants with a single vendor. However, it is currently unknown whether sole-source contracting or vendor rationalization more broadly affects patient care. To describe the single-vendor procurement of spinal implants, characterize the economic benefits of sole-source contracting, and gauge whether vendor rationalization is associated with a diminished quality of care. This retrospective cohort study assessed adult patients receiving single-level lumbar interbody fusions at a single institution from January 1, 2009, to July 31, 2017. Exclusion criteria included multilevel fusions and prior spinal fusions. Patients were analyzed based on the number of vendors available to surgeons at the time of the patient's surgery. January 1, 2009, to December 31, 2010, was defined as the multivendor period (10 vendors); January 1, 2011, to December 31, 2014, was defined as the dual-vendor period; and January 1, 2015, to July 31, 2017, was defined as the single-vendor period. Rates of 12-month revision surgery, complications, 30-day readmissions, and postoperative patient-reported outcomes, as measured by 5-dimension European Quality of Life (EQ-5D) and Patient-Reported Outcomes Measurement Information System-Global Health (PROMIS-GH) utilities. Propensity score weighting was performed to control for confounding. The Holm method was used to correct for multiple testing. Annual cost savings associated with the dual-vendor and single-vendor periods were also reported. A total of 1373 patients (mean [SD] age, 59.2 [12.6] years; 763 [55.6%] female; 1161 [84.6%] white) were analyzed. Rates of revisions after adjusting for confounding were 3.2% (95% CI, 1.5%-6.7%) for the multivendor period, 4.5% (95% CI, 3.1%-6.5%) for the dual-vendor period, and 3.0% (95% CI, 1.7%-5.0%) for the single-vendor period. Complication rates were 5.3% (95% CI, 2.7%-10.1%) for the multivendor period, 7.2% (95% CI, 5.4%-9.6%) for the dual-vendor period, and 6.4% (95% CI, 4.6%-8.8%) for the single-vendor period. Readmission rates were 14.2% (95% CI, 9.7%-20.2%) for the multivendor period, 12.6% (95% CI, 10.1%-15.5%) for the dual-vendor period, and 9.7% (95% CI, 7.4%-12.7%) for the single-vendor period. Revisions, complications, and patient-reported outcomes were statistically equivalent across all periods. Readmissions were not statistically equivalent but not statistically different. The savings attributable to vendor rationalization were 24% for the dual-vendor and 21% for the single-vendor periods. The single-vendor procurement of spinal implants was associated with significant cost savings without evidence of an associated decline in the quality of care. Large hospital systems may consider sole-source purchasing as a viable cost reduction strategy.

Spinopelvic Compensatory Mechanisms for Reduced Hip Motion (ROM) in the Setting of Hip Osteoarthritis

Study DesignRetrospective review from a single institution. ObjectiveTo investigate the effect of hip osteoarthritis (OA) on spinopelvic compensatory mechanisms as a result of reduced hip range of motion (ROM) between sitting and standing. Summary of Background DataHip OA results in reduced hip ROM and contracture, causing pain during postural changes. Hip flexion contracture is known to reduce the ability to compensate for spinal deformity while standing; however, the effects of postural spinal alignment change between sitting and standing is not well understood. MethodsSit-stand radiographs of patients without prior spinal fusion or hip prosthesis were evaluated. Hip OA was graded by Kellgren-Lawrence grades and divided into low-grade (LOA; grade 0–2) and severe (SOA; grade 3 or 4) groups. Radiographic parameters evaluated were pelvic incidence (PI), pelvic tilt (PT), lumbar lordosis (LL), PI-LL, thoracic kyphosis (TK), SVA, T1-pelvic angle (TPA), T10–L2, proximal femoral shaft angle (PFSA), and hip flexion (PT change–PFSA change). Changes in sit-stand parameters were compared between LOA and SOA groups. Results548 patients were included (LOA = 311; SOA = 237). After propensity score matching for age, body mass index, and PI, 183 LOA and 183 SOA patients were analyzed. Standing analysis demonstrated that SOA had higher SVA (31.1 vs. 21.7), lower TK (−36.2 vs. −41.1), and larger PFSA (9.1 vs. 7.4) (all p < .05). Sitting analysis demonstrated that SOA had higher PT (29.7 vs. 23.3), higher PI-LL (21.6 vs. 12.4), less LL (31.7 vs. 41.6), less TK (−33.2 vs. −38.6), and greater TPA (27.9 vs. 22.5) (all p < .05). SOA had less hip ROM from standing to sitting versus LOA (71.5 vs. 81.6) (p < .05). Therefore, SOA had more change in PT (15.2 vs. 7.3), PI-LL (20.6 vs. 13.7), LL (−21.4 vs. −13.1), and T10–L2 (−4.9 vs. −1.1) (all p < .001), allowing the femurs to change position despite reduced hip ROM. SOA had greater TPA reduction (15.1 vs. 9.6) and less PFSA change (86.7 vs. 88.8) compared with LOA (both p < .001). ConclusionsSpinopelvic compensatory mechanisms are adapted for reduced hip joint motion associated with hip OA in standing and sitting. Level of EvidenceLevel III.

Thursday, September 27, 2018 8:30 AM–9:30 AM Best Papers: 108. Spinopelvic compensatory mechanisms for reduced hip motion (ROM) in the setting of hip osteoarthritis

BACKGROUND CONTEXT Spinopelvic compensatory mechanisms for reduced hip motion (ROM) in the setting of hip osteoarthritis. PURPOSE Hip osteoarthritis (OA) results in reduced hip range of motion, which affects sitting and standing posture. Spinal pathology (eg, fusion or deformity) may alter the ability to compensate for reduced joint mobility associated with hip OA in sitting and standing postures; however, the effect of hip OA on postural spinal alignment between sitting and standing remains unreported. In patients with severe hip OA, spinopelvic compensatory mechanisms can be compromised leading to greater pelvic tilt (PT) and lumbar lordosis (LL) change. STUDY DESIGN/SETTING Retrospective clinical and radiographic analysis at a single institution of patients with OA between 2012 and 2017. PATIENT SAMPLE A total of 548 patients with sit-stand radiographs. OUTCOME MEASURES Spinal and lower limb alignment Pelvic Incidence (PI), PT, LL, PI-LL, Thoracic Kyphosis (TK), Global alignment (SVA & T1-Pelvic Angle (TPA), T10-L2, proximal femoral shaft angle (PFSA: as measured from the vertical), sacrofemoral angle (SFA), Knee Flexion (KA) and hip ROM (difference between PT change and PFSA change). METHODS Hip OA severity was graded by Kellgren-Lawrence scale and divided into two groups: low-grade (LOA; grades 0-2) and severe (SOA; grades 3-4). Patients were excluded if they had transitional lumbosacral anatomy, prior spinal fusion or hip prosthesis. Changes in sit-stand alignment were compared between LOA and SOA by unpaired t-test RESULTS A total of 548 patients were identified with sit-stand radiographs, of which there were 311 patients with LOA and 237 with SOA. After propensity score matching for age, BMI, PI and standing SVA, 183 LOA & 183 SOA patients were analyzed. Standing alignment analysis demonstrated that SOA patients had lower PT (14.49 ± 9.2 vs. 16.78 ± 8.14, p CONCLUSIONS Spinopelvic compensatory mechanisms are adapted for reduced hip ROM in SOA between standing and sitting. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.

Decompression and instrumentation without fusion for spinal metastases: Loosening rate and consequences

Background/PurposeFor patients with spinal metastases, decompression surgery was usually followed by instrumentation without fusion. Over time, mechanical stress would lead to loosening of implants. Yet, there is a lack of studies concerning the loosening rate, or the impact on patients when the implants are loosened. We aim at finding the postoperative loosening rate of implant, postoperative survivorship of patients, as well as their correlation with the mode of instrumentation. MethodsA retrospective study including patients with metastatic spinal cord compression, who received decompression and instrumentation without fusion in a local hospital in Hong Kong from 2007 to 2014 was carried out. Patients with primary spinal tumour or prior spinal fusion were excluded. Demographics, tumour characteristics, mode of instrumentation, loosening rate of implants, as well as survivorship of patients were retrieved. Radiographs at 1 year postoperation were counter-examined by 2 Orthopaedic specialists on the Electronic Patient Record System. ResultsTotal of 65 operations were retrieved. The age ranged from 27 to 84 years old. The most frequent primary source of malignancy was lung (26.5%), followed by breast (24.62%). Thoracic level (60%) was the most frequent site of spinal metastases. The survivorship at 1 year postoperation was 61.54%. The overall loosening rate of implants was 44.44%, with the Luque rods and sublaminar wire system being the most (70%). None of the cases required revision or removal of implants at 1 year postoperation. ConclusionThe loosening rate of implants was high, and it is expected to grow even higher as oncological patients continue to improve in their survivorship with the medical advances such as target therapy. Yet there is still no definite evidence on how the implant loosening would affect patients' quality of life and clinical performance.

Posterior-Only Vertebral Column Resection for Fused Spondyloptosis

Study DesignRetrospective review. ObjectivesTo describe 3 cases of a posterior-only vertebral column resection (pVCR) for the treatment of spondyloptosis in the setting of prior spinal fusions. Summary of Background DataLumbosacral spondyloptosis is a rare spinal deformity with a number of surgical options, none of which demonstrate clear superiority. The use of an L5 vertebral column resection, via combined anterior and posterior approaches, to restore lumbosacral alignment has been described though is accompanied by high rates of neurological deficit. MethodsReview of 3 cases of spondyloptosis with prior spinal fusions in which a staged pVCR was used for deformity reconstruction. ResultsThree females, ages 39, 54, and 28, developed spondyloptosis with progressive lumbosacral kyphosis and sagittal malalignment after prior in-situ posterolateral spinal fusions. All were treated with staged pVCRs. At ultimate follow-up, imaging revealed improvement in sagittal balance of 6.1 cm (56%) in the 39-year-old and 12 cm (67%) in the 54-year-old, 21.1 cm (92%) in the 28-year-old. All patients had improvement in outcome scores with perfect satisfaction scores despite the 54-year-old having a persistent right foot drop. ConclusionPosterior-only VCR for spondyloptosis is a technically demanding surgical option offering significant radiographic and clinical improvement, but carries a risk for L5 nerve root deficit as in any spondyloptosis treatment.

The impact of curve severity on obstetric complications and regional anesthesia utilization in pregnant patients with adolescent idiopathic scoliosis: a preliminary analysis.

OBJECTIVE Adolescent idiopathic scoliosis (AIS), the most common type of scoliosis, often presents immediately prior to a woman's childbearing years; however, research investigating the impact of AIS on women's health, particularly pregnancy delivery outcomes, is sparse, with existing literature reporting mixed findings. Similarly limited are studies examining the change in scoliotic curve during or after pregnancy. Therefore, this study aims to determine 1) the impact of scoliotic curvature on obstetric complications (preterm births, induction of labor, and urgent/emergency caesarean section delivery), 2) regional anesthetic decision making and success during delivery for these patients, and 3) the effect of pregnancy on curve progression. METHODS Records of all pregnant patients diagnosed with AIS at the authors' institution who delivered between January 2002 and September 2016 were retrospectively reviewed. Demographic information, pre- and postpartum radiographic Cobb angles, and clinical data for each pregnancy and delivery were recorded and analyzed. The Wilcoxon rank-sum test and the Wilcoxon signed-rank test were used for statistical analyses. RESULTS Fifty-nine patients (84 deliveries) were included; 14 patients had undergone prior posterior spinal fusion. The median age at AIS diagnosis was 15.2 years, and the median age at delivery was 21.8 years. Overall, the median major Cobb angle prior to the first pregnancy was 25° (IQR 15°-40°). Most births were by spontaneous vaginal delivery (n = 45; 54%); elective caesarean section was performed in 17 deliveries (20%). Obstetric complications included preterm birth (n = 18; 21.4%), induction of labor (n = 20; 23.8%), and urgent/emergency caesarean section (n = 12; 14.0%); none were associated with severity of scoliosis curve or prior spinal fusion. Attempts at spinal anesthesia were successful 99% of the time (70/71 deliveries), even among the patients who had undergone prior spinal fusion (n = 13). There were only 3 instances of provider refusal to administer spinal anesthesia. In the subset of 11 patients who underwent postpartum scoliosis radiography, there was no statistically significant change in curve magnitude either during or immediately after pregnancy. CONCLUSIONS The results of this study suggest that there was no effect of the severity of scoliosis on delivery complications or regional anesthetic decision making in pregnant patients with AIS. Moreover, scoliosis was not observed to progress significantly during or immediately after pregnancy. Larger prospective studies are needed to further investigate these outcomes, the findings of which can guide the prenatal education and counseling of pregnant patients with AIS.

143 - Do Prior Spinal Fusions Affect Physical Activity following Total Hip Arthroplasty? Results from a National Spine and Hip Registry

BACKGROUND CONTEXT: Physical activity (PA) has been used as a patient outcome measure after surgical procedures such as spine and hip surgery. The effect on PA with the combination of both these procedures is unknown. It is hypothesized that patients with prior spinal fusions (SF) would have slower recoveries and decreased PA after total hip arthroplasties (THA).

Effect of Spinal Fusion Surgery on Total Hip Arthroplasty Outcomes: A Matched Comparison Study

BackgroundStudies regarding postoperative outcomes after primary total hip arthroplasty (THA) in patients who have comorbid factors tend to focus on medical diseases. However, there is a paucity of literature examining the effect of a patient's orthopedic surgical history on outcomes after THA. Significantly, there are currently no studies on the effect of spinal fusion surgery on THA outcomes. MethodsA review of 82 consecutive patients who had prior spinal fusion surgery who underwent elective THA from January 1, 2006 to December 31, 2015, was conducted. A matching cohort of 82 patients was selected from the remaining THA patients to maintain a 1:1 ratio control group. This cohort of 82 patients was matched for age, gender, body mass index ±5, preoperative Oxford score ±10, total Short Form-36 score ±10, and total Western Ontario and McMaster Universities Arthritis Index (WOMAC) score ±50. Data on the same functional outcomes were prospectively collected at 6-month and 2-year follow-up for comparison. ResultsPatients without spinal fusion had better outcome scores than patients with prior spinal fusion, specifically in their 6-month WOMAC scores (253.33-225.07; P = .046), their 2-year Short Form-36 total scores (79.71-69.21; P = .041), and their 2-year WOMAC scores (213.5-267.41; P = .054). ConclusionThis study demonstrates that patients with prior spinal fusion had worse outcomes after THA than patients without prior spinal fusion. This has clinical significance in counseling patients with previous spinal fusion undergoing THA.