Faculty Bibliography

Hypothesis: Mechanisms of relaxation after sagittal correction may differ from the compensation mechanisms of sagittal deformity development. Design: Retrospective cohort. Introduction: Adult spinal deformity patients recruit compensatory mechanisms to maintain alignment with increasing deformity. While attention has been paid to pre-operative compensatory adaptations, little is known regarding the sequence of relaxation of these parameters based upon the amount of residual PI-LL mismatch. This study details the progression of compensatory mechanism relaxation as PILL mismatch improves. Methods: Single site review of post-operative full-body x-rays of patients, at least 9 months after surgery. Radiographic measurements were obtained with dedicated spine software and included PT, knee flexion (KA), ankle dorsiflexion (AD), pelvic shift (PShift), T1 spinopelvic inclination (T1SPi), SVA and T1 pelvic angle (TPA). Patients were stratified by their remaining need for lordosis based on ageadjusted normative published values. Group comparisons were carried out via ANOVA analysis. Results: 262 patients were included, mean age 61.5, mean BMI 28, and males 31 %. PI-LL groups were significantly (p<0.05) different in terms of PT, KA, PShift, TPA, SVA and AD (Fig). Analysis of the sequence of correction revealed that the majority of age-adjusted offset in terms of SVA and PT was corrected (59 %, 57 %) during the first stage of correction ([>30degree] to [20degree-30degree] of remaining need for lordosis). This stage was associated with significant changes in PShift and T1SPi (p<0.05). Additional stages of corrections were associated with gradual decreases in SVA, while no additional decreases in PT were observed until the post-operative lordosis was near ideal. Conclusions: When improving from severe to moderate age-adjusted PI-LL mismatch, there is a correction in age-adjusted SVA to normal range. Nevertheless, these patients still exhibit high degree of compensation with respect to the pelvis and lower limbs to maintain alignment. PT and SVA can be corrected to an age-adjusted ideal when PI-LL is also corrected

Hypothesis: Global sagittal angle is clinically relevant. Design: Single center retrospective review. Introduction: According to Dubousset's "conus of economy" theory, deterioration of sagittal alignment requires higher energy expenditure to maintain erect posture. Since the clinical impact of sagittal alignment is affected both by the severity of the deformity and a patient's inability to recruit compensatory mechanisms, it is important to investigate new parameters that reflect both disability level and compensatory mechanisms for all patients. This study investigates the clinical relevance of the GSA. Methods: Retrospective review of patients who underwent full body X-rays and completed ODI and SRS-22. GSA was defined as the angle subtended by a line from the midpoint of the femoral condyles to the center of >7, and a line from the midpoint between the femoral condyles to the posterior superior corner of the S1 sacral endplate. After evaluating the correlation of GSA/ODI with classic sagittal parameters, linear regression models were generated to investigate how ODI related to radiographic parameters (TPA, PT). TPA and PT's relation to GSA was then investigated. Results: 143 patients (mean 44y) were identified. GSA correlated significantly with ODI, PT, SVA, TPA and lower limb alignment. Regression between ODI and classic parameters only retained GSA as independent predictor (r = 0.517, r2 = 0.267, p<0.001). Analysis of standardized coefficients revealed that GSA increases when TPA increases (beta: 1.991) with concurrent decrease in PT (-1.323). These findings echoed those of ODI, which increased with increased TPA (beta: 1.038) and decreased PT (-0.696). Conclusions: GSA goes further than classic parameters and quantifies the clinical impact of all patients' compensation mechanisms in addition to their malalignment. Analyzing the relationship between GSA and PT revealed that compensation is the body's defense against malalignment, and patients who lack compensation have both higher GSA and higher ODI scores. GSA is a significant and clinically relevant metric that quantifies both spinal deformity and disability even among those with alternative compensation mechanisms

Few studies about how heterotopic ossification (HO) affects functional outcome after metal-on-metal total hip resurfacing (MOMHR) have been reported. The purpose of this study was to evaluate the incidence and clinical significance of HO after MOMHR. We retrospectively reviewed 122 consecutive patients, who underwent MOMHR from June 2006 to October 2008, with adequate follow-up information. All patients had four weeks of aspirin (325 mg twice a day) for DVT prophylaxis and two weeks of celecoxib (400 mg once a day) for pain control. All data were collected prospectively including radiographs and functional scores preoperatively, at three months and at one year postoperatively. An independent musculoskeletal radiologist, using the Brooker classification, reviewed radiographs. Unbalanced ANOVA analyses were performed to evaluate the effect of HO on outcome. The overall incidence of HO at three months was 62.1% (grade 1: 39.8%, grade 2: 20.4%, grade 3: 1.9%) and 75% at one year (grade 1: 41.7%, grade 2: 27.8%, grade 3: 5.5%). There were no significant differences in the functional status scores among Brooker grade 0 to 3 groups at three months and one year follow-up. The incidence of HO after MOMHR was 62.1% at three months and 75% at one year despite a post-operative regimen of aspirin and celecoxib. We found no evidence that predominantly Brooker grade 1 or 2 HO affected the clinical outcome at three months or one year when compared across all Brooker classes of patients.

As quality measures may be increasingly used in knee surgery reimbursement, an important focus in outcome assessment will shift toward minimizing complications and increasing efficiency in knee arthroplasty reconstruction. The purpose of this study was to evaluate the efficacy of barbed, absorbable sutures in closure of the longitudinal surgical incision following knee arthroplasty, using post-operative complication occurrences. In 416 operations, primary outcomes assessed were deep infection, superficial infection, dehiscence, or stitch abscesses. Secondary outcomes included self-limiting eschar, severe effusion, arthrofibrosis, and keloid formation. Evaluation of overall primary outcomes showed a higher rate of wound complications using barbed sutures (P < 0.001). With increased rates of infection and overall closure related complications, this study shows that barbed suture use for superficial closure after knee arthroplasty should be avoided.

BACKGROUND CONTEXT: A large percentage of patients with adult spinal deformity (ASD), up to 52% in the literature, gain a minimal clinically important difference (MCID) in one or more of the health-related quality of life (HRQOLs) instruments. PURPOSE: This study attempts to identify and describe baseline characteristics of this subset of nonoperative patients who improve, and propose possible predictors of MCID gain in SRS Activity or Pain. STUDY DESIGN/SETTING: Post-hoc analysis of prospective, multicenter database of operative and nonoperative patients with ASD. PATIENT SAMPLE: 215 nonoperative patients with ASD with minimum 2-year follow-up and an MCID deficit in either SRS Activity or Pain. OUTCOME MEASURES: SRS Activity, SRS Pain, MCID, spinopelvic radiographic parameters. METHODS: Post-hoc analysis of prospective, multicenter, case series of 215 nonoperative patients with ASD with minimum 2-year follow-up and an MCID deficit (need for improvement) at baseline in SRS Pain or Activity scores compared to the normative population. Using a multivariate analysis, 2 groups were compared to identify possible predictors: those that reached an MCID in SRS Pain or Activity (n=86) at 2 years and those that missed MCID (n=129). RESULTS: At baseline, 215 nonoperative patients with ASD needed to improve in SRS Activity or Pain, and there were no statistically significant differences in age, BMI or baseline SVA (17.5mm v 20.5mm p 0.70) between the cohorts that improved and did not improve. At 2-year followup, 40% (n = 86) reached MCID and 60% (n = 129) missed MCID. Of the nonoperative patients who reached MCID at 2 years, they had at baseline a significantly lower SRS Pain (3.0 v 3.6, p<0.05), thoracolumbar Cobb (29.6degree v 36.5degree, p<0.05, 87 patients with Schwab classification Lumbar or Double), sacral slope (33.1degree v 36.4degree, p<0.05) and lumbar lordosis (46.5degree v 52.8degree, p<0.05). PI-LL was significant on univariate analysis but not by multivariate (7.5degree v 2.6degree, p 0.14). !

BACKGROUND CONTEXT: Corrective surgery for adult spinal deformity (ADS) provides long-term benefits but often at the cost of significant perioperative morbidity. The use of minimally invasive surgery (MIS) for correction of ADS has been theorized to lower the perioperative morbidity when compared to traditional open surgical approaches. However, there is concern that patients treated with MIS techniques will not achieve the same level of clinical improvement as those treated with traditional open surgery approaches. This study compared patients treated with MIS (MIS lateral or transforaminal interbody fusion (LIF or TLIF) with percutaneous pedicle screw fixation), hybrid techniques (HYB) (MIS LIF or TLIF in combination with open posterior pedicle screw fixation), and open techniques to assess ODI at 1 and 2 years. PURPOSE: To compare disability outcomes between open and MIS deformity surgery. STUDY DESIGN/SETTING: Retrospective review of propensity matched cohorts. PATIENT SAMPLE: 120 patients with adult deformity treated with MIS, hybrid or open surgeries. OUTCOME MEASURES: Radiographic parameters and ODI. METHODS: All cases were reviewed retrospectively. Inclusion criteria included: age>18yr, ASD, min 2-yr follow-up. Patients treated for adult spinal deformity using either less invasive or open surgical approaches were propensity matched by preop SVA, baseline ODI, and by number of fused levels. Patients' results were compared at 1 and 2 years postop. RESULTS: 40 patients were propensity matched into each group for a total number of 120. Mean number of levels fused and SVAwas HYB = 5.9, 37.7mm, MIS = 3.7, 30.7mm, OPEN = 6.0, 47.5 mm. At baseline, ODI was: HYB569.6, MIS549.7, Open549.6. At postop 1 year patients reported significantly improved ODI (P<0.01 when compared to baseline) (HYB537.3, MIS526.8, Open535.6) (between groups P>0.05). At 2 years the patients maintained improvement in disability (HYB537.5, SVA 43.6, MIS 28.0, SVA 34.5, and Open 30.6, SVA 33.5). CONCLUSIONS: Patients treated !

BACKGROUND CONTEXT: The maintenance of horizontal gaze is an essential function of upright posture and global sagittal spinal alignment. Horizontal gaze is classically measured by the Chin Brow Vertical Angle (CBVA), which is not readily measured on most lateral spine radiographs. PURPOSE: This study proposes to evaluate the correlation of CBVA with two more accessible angles: the Slope of the Line of Sight (SLS) (slope of Frankfort line: anterior/inferior margin of orbit to the top of the external auditory meatus) and the slope of McGregor's line (McGS). Furthermore, this study also aims to correlate these 3 angles with HRQOL, specifically the Oswestry Disability Index (ODI). STUDY DESIGN/SETTING: Single-center, retrospective, non-consecutive case series. PATIENT SAMPLE: 531 Patients with spinal pathologies (primary cervical, lumbar, or adult scoliosis) from November 2012 to November 2013. OUTCOME MEASURES: Oswestry Disability Index (ODI). METHODS: Patients were identified from a multicenter database of 531 spine patients who underwent full body EOS X-rays with a variety of presenting complaints (primary cervical, lumbar, or adult scoliosis). Exclusion criteria were age<18y, total hip arthroplasty, total knee arthroplasty, neuropathic scoliosis, fractures, and tumor. Correlations between CBVA, SLS, and McGS and were assessed. Using a quadratic regression with ODI and CBVA, we established a low disability range of values for the CBVA and then, by simple regression, a low disability range of values for SLS and McGS. RESULTS: 435 patients were included (67% females, mean age 57 +; 15yo, mean BMI 27.4 +; 6.4 kg/m²). CBVA strongly correlated with SLS (r=.996, p<.001) and McGS (r=.862, p<.001). A significant negative correlation was observed between ODI and all 3 angles (with CBVA: r= -0.232, p=.022, with SLS: r=-0.228, p=.024, with McGS: r=-0.213, p=.036). By applying a quadratic regression on the ODI and CBVA establishing range of values corresponding to low disability (-4.7degree to 17!

BACKGROUND CONTEXT: Previous force plate studies analyzing the impact of sagittal spinal deformity (SSD) on pelvic parameters have demonstrated compensatory mechanisms of translation in addition to rotation. However, compensatory changes in the hip, knee and ankle joints have not been assessed in patients with sagittal malalignment. PURPOSE: This study aims to 1) analyze the relationship between sagittal spinopelvic (SPP) and lower limb (LLP) parameters, 2) to clarify the role of pelvic translation (pelvic shift) and 3) to correlate Oswestry Disability Index with spinopelvic parameters and compensatory mechanisms. STUDY DESIGN/SETTING: Retrospective single center study. PATIENT SAMPLE: From November 2012 to November 2013, 409 patients with spinal deformity and full-body EOS images (EOS system) were included, without age or gender restriction. Patients with only a diagnosis of stenosis or low back pain were excluded. Subjects were grouped by T1 Spino Pelvic inclination (T1SPi): sagittal forward (FW, > 0.6degree), neutral (NE, -6.6degree to 0.6degree) and backward (BW,<-6.6degree). OUTCOME MEASURES: T1SPi, Pelvic Shift (P.Shift), sagittal vertical axis (SVA), pelvic tilt (PT), lumbar lordosis (LL), "pelvic incidence minus lumbar lordosis" (PI-LL), TK (T1T12 kyphosis), T9SPi (T9 spinopelvic inclination), Sacro Femoral Angle (SFA), Knee Angle, Ankle Angle, chin brow vertical angle, and ODI (Oswestry Disability Index). METHODS: Pelvic translation was quantified by Pelvic Shift (the sagittal offset between the postero-superior corner of the sacrum and the anterior cortex of distal tibia). SPP were measured such as: SVA, PT, PI-LL, TK, T9SPi. Hip extension was measured using the SFA (angle between a line from middle of sacral endplate to bicoxo femoral axis and the femoral mechanical axis), Knee Angle (KA, angle of knee flexion), and Ankle Angle (AA, between tibial axis and vertical reference line) were positive in case of flexion. CBVA (chin brow vertical angle, between the chin-brow line and the ver!

BACKGROUND CONTEXT: 3-column osteotomy (3CO) is an effective technique to correct sagittal malalignment, but is associated with high complication rates. However the distribution of correction of global truncal alignment versus pelvic retroversion remains unclear, with a belief that more caudal osteotomy leads to larger correction. PURPOSE: This study sought to investigate the impacts of osteotomy site and postoperative apex of lumbar lordosis 1) on sagittal correction and 2) on postoperative complications and revisions rates. STUDY DESIGN/SETTING: Radiographic retrospective study of a multicenter database. PATIENT SAMPLE: 347 adult spinal deformity patients with 2-year follow-up, upper instrumented vertebra above L1, and lumbar 3CO were included. OUTCOME MEASURES: 3CO resection angle, sagittal vertical axis (SVA), pelvic tilt (PT), lumbar lordosis (LL), LL apex, pelvic incidence minus lumbar lordosis (PI-LL). METHODS: Radiographic, demographic, and OR data, revisions and complications, were analyzed at baseline, 6m, 1Y, 2Y FU to quantify spinopelvic alignment, apex of lordosis, resection angle and complications or revisions rates. Uni- and multivariate analyses were performed and correlations were tested using Pearson for continuous variables and Spearman for apex or osteotomy level. RESULTS: 347 patients were included (mean age 60 yrs, BMI 28kg/m², 69% female). Preoperative parameters demonstrated a severe deformity (PT: 32.6degree +; 10.9, SVA: 145.6 +; 78.6mm, PI-LL: 36.8degree +; 19.3). Average resection angle was 25.3degree without significant difference across 3CO levels. Postoperatively, all these parameters were significantly improved (at 1 year, PT: 23.9degree +; 11.5, SVA: 45.7degree +; 63.4, PI-LL: 5.2degree +; 18.0, p<0.001). There were no significant correlations between 3CO level and amount of SVA or PT correction (postoperative change in SVA: -106.8degree +; 76.8, in PT: -8.7degree +; 9.2). Postop apex location, which was more caudal than 3CO level, significantly corre!

BACKGROUND CONTEXT: While the SRS-Schwab classification offers a framework defining the alignment categories of adult spinal deformity (ASD) patients, one can wonder if a "one-fits all" solution is appropriate as age-related changes in alignment and patient reported outcomes have been established in the literature. The objective of this study was to investigate age specific alignment thresholds based on US norms SF-36 Physical Component Score (PCS). PURPOSE: To investigate postoperative alignment parameters and HRQOL to determine the validity of targets of correction according to patient age. STUDY DESIGN/SETTING: Retrospective review of a multicenter, prospective consecutive database. PATIENT SAMPLE: 773 patients with adult spinal deformity who received operative and nonoperative treatment. OUTCOME MEASURES: Oswestry Disability Index (ODI) and Short- Form (SF)-36 Physical Component Score (PCS). METHODS: Retrospective review of a multicenter consecutive prospective database of ASD patients who received surgical (OP) or nonoperative (NON) treatment. Patients were stratified by age groups in line with the US norm published values of the SF-36 PCS (under 35 yo, 35-44 yo, 45-54 yo, 55-64 yo, 65-74 yo, over 75 yo). At baseline, relationship between radiographic alignment parameters (PI-LL, PT, SVA, and TPA), age and PCS were established using linear regression analysis and subsequently applied with US-norm PCS values to established agespecific thresholds of alignment. Finally a correlation analysis was performed between ODI and PCS to report alignment thresholds by age. This process was repeated at 2-year follow-up to investigate changes in radiographic parameters corresponding to 1 MICD improvement for the different age groups. RESULTS: Baseline analysis included 773 patients (53.7 yo, 54% OP, 83% female). There was a strong correlation between ODI and PCS (r=0.814, p<0.001) permitting an extrapolation of US norm ODI by age groups. Linear regression analysis (all with r > 0.510, p<0.001) combined w!