Browsing by Author "Kim, Han J"

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    ItemOpen Access
    Are the Arbeitsgemeinschaft Für Osteosynthesefragen (AO) Principles for Long Bone Fractures Applicable to 3-Column Osteotomy to Reduce Rod Fracture Rates?
    (Clinical spine surgery, 2022-06) Virk, Sohrab; Lafage, Renaud; Bess, Shay; Shaffrey, Christopher; Kim, Han J; Ames, Christopher; Burton, Doug; Gupta, Munish; Smith, Justin S; Eastlack, Robert; Klineberg, Eric; Mundis, Gregory; Schwab, Frank; Lafage, Virginie; International Spine Study Group

    Objective

    The aim was to determine whether applying Arbeitsgemeinschaft für Osteosynthesefragen (AO) principles for external fixation of long bone fracture to patients with a 3-column osteotomy (3CO) would be associated with reduced rod fracture (RF) rates.

    Summary of background data

    AO dictate principles to follow when fixating long bone fractures: (1) decrease bone-rod distance; (2) increase the number of connecting rods; (3) increase the diameter of rods; (4) increase the working length of screws; (5) use multiaxial fixation. We hypothesized that applying these principles to patients undergoing a 3CO reduces the rate of RF.

    Methods

    Patients were categorized as having RF versus no rod fracture (non-RF). Details on location and type of instrumentation were collected. Dedicated software was used to calculate the distance between osteotomy site and adjacent pedicle screws, angle between screws and the distance between the osteotomy site and rod. Classic sagittal spinopelvic parameters were evaluated.

    Results

    The study included 170 patients (34=RF, 136=non-RF). There was no difference in age (P=0.224), sagittal vertical axis correction (P=0.287), or lumbar lordosis correction (P=0.36). There was no difference in number of screws cephalad (P=0.62) or caudal (P=0.31) to 3CO site. There was a lower rate of RF for patients with >2 rods versus 2 rods (P<0.001). Patients with multiplanar rod fixation had a lower rod fracture rate (P=0.01). For patients with only 2 rods (N=68), the non-RF cohort had adjacent screws that trended to have less angulation to each other (P=0.06) and adjacent screws that had a larger working length (P=0.03).

    Conclusions

    A portion of AO principles can be applied to 3CO to reduce RF rates. Placing more rods around a 3CO site, placing rods in multiple planes, and placing adjacent screws with a larger working length around the 3CO site is associated with lower RF rates.
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    ItemOpen Access
    Baseline Patient-Reported Outcomes Correlate Weakly With Radiographic Parameters: A Multicenter, Prospective NIH Adult Symptomatic Lumbar Scoliosis Study of 286 Patients.
    (Spine, 2016-11) Chapman, Todd M; Baldus, Christine R; Lurie, Jon D; Glassman, Steven D; Schwab, Frank J; Shaffrey, Christopher I; Lafage, Virginie; Boachie-Adjei, Oheneba; Kim, Han J; Smith, Justin S; Crawford, Charles H; Lenke, Lawrence G; Buchowski, Jacob M; Edwards, Charles; Koski, Tyler; Parent, Stefan; Lewis, Stephen; Kang, Daniel G; McClendon, Jamal; Metz, Lionel; Zebala, Lukas P; Kelly, Michael P; Spratt, Kevin F; Bridwell, Keith H

    Study design

    Prospective, cross-sectional study.

    Objective

    The aim of the study was to determine which radiographic parameters drive patient-reported outcomes (PROs) in primary presentation adult symptomatic lumbar scoliosis (ASLS).

    Summary of background data

    Previous literature suggests correlations between PROs and sagittal plane deformity (sagittal vertical axis [SVA], pelvic incidence-lumbar lordosis [PI-LL] mismatch, pelvic tilt [PT]). Prior work included revision and primary adult spinal deformity patients. The present study addresses only primary presentation ASLS.

    Methods

    Prospective baseline data were analyzed on 286 patients enrolled in an NIH RO1 clinical trial by nine centers from 2010 to 2014.

    Inclusion criteria

    40 to 80 years old, lumbar Cobb (LC) 30° or higher and Scoliosis Research Society-23 score 4.0 or less in Pain, Function or Self-Image domains, or Oswestry Disability Index (ODI) 20 or higher. Patients were primary presentation (no prior spinal deformity surgery) and had complete baseline data: standing coronal/sagittal 36" radiographs and PROs (ODI, Scoliosis Research Society-23, Short Form-12). Correlation coefficients were calculated to evaluate relations between radiographic parameters and PROs for the study population and a subset of patients with ODI 40 or higher. Analysis of variance was used to identify differences in PROs for radiographic modifier groups.

    Results

    Mean age was 60.3 years. Mean spinopelvic parameters were: LL = -39.2°; SVA = 3.1 cm; sacral slope = 32.5°; PT = 23.9°; PI-LL mismatch = 16.8°. Only weak correlations (0.2-0.4) were identified between population sacral slope, SVA and SVA modifiers, and SRS function. SVA and SVA modifiers were weakly associated with ODI. Although there were more correlations in subset analysis of high-symptom patients, all were weak. Analysis of variance identified significant differences in ODI reported by SVA modifier groups.

    Conclusion

    In primary presentation patients with ASLS and a subset of "high-symptom" patients (ODI ≥ 40), only weak associations between baseline PROs and radiographic parameters were identified. For this patient population, these results suggest regional radiographic parameters (LC, LL, PT, PI-LL mismatch) are not drivers of PROs and cannot be used to extrapolate effect on patient-perceived pathology.

    Level of evidence

    2.
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    ItemOpen Access
    Defining Spino-Pelvic Alignment Thresholds: Should Operative Goals in Adult Spinal Deformity Surgery Account for Age?
    (Spine, 2016-01) Lafage, Renaud; Schwab, Frank; Challier, Vincent; Henry, Jensen K; Gum, Jeffrey; Smith, Justin; Hostin, Richard; Shaffrey, Christopher; Kim, Han J; Ames, Christopher; Scheer, Justin; Klineberg, Eric; Bess, Shay; Burton, Douglas; Lafage, Virginie; International Spine Study Group

    Study design

    Retrospective review of prospective, multicenter database.

    Objective

    The aim of the study was to determine age-specific spino-pelvic parameters, to extrapolate age-specific Oswestry Disability Index (ODI) values from published Short Form (SF)-36 Physical Component Score (PCS) data, and to propose age-specific realignment thresholds for adult spinal deformity (ASD).

    Summary of background data

    The Scoliosis Research Society-Schwab classification offers a framework for defining alignment in patients with ASD. Although age-specific changes in spinal alignment and patient-reported outcomes have been established in the literature, their relationship in the setting of ASD operative realignment has not been reported.

    Methods

    ASD patients who received operative or nonoperative treatment were consecutively enrolled. Patients were stratified by age, consistent with published US-normative values (Norms) of the SF-36 PCS (<35, 35-44, 45-54, 55-64, 65-74, >75  y old). At baseline, relationships between between radiographic spino-pelvic parameters (lumbar-pelvic mismatch [PI-LL], pelvic tilt [PT], sagittal vertical axis [SVA], and T1 pelvic angle [TPA]), age, and PCS were established using linear regression analysis; normative PCS values were then used to establish age-specific targets. Correlation analysis with ODI and PCS was used to determine age-specific ideal alignment.

    Results

    Baseline analysis included 773 patients (53.7 y old, 54% operative, 83% female). There was a strong correlation between ODI and PCS (r = 0.814, P < 0.001), allowing for the extrapolation of US-normative ODI by age group. Linear regression analysis (all with r > 0.510, P < 0.001) combined with US-normative PCS values demonstrated that ideal spino-pelvic values increased with age, ranging from PT = 10.9 degrees, PI-LL = -10.5 degrees, and SVA = 4.1 mm for patients under 35 years to PT = 28.5 degrees, PI-LL = 16.7 degrees, and SVA = 78.1 mm for patients over 75 years. Clinically, older patients had greater compensation, more degenerative loss of lordosis, and were more pitched forward.

    Conclusion

    This study demonstrated that sagittal spino-pelvic alignment varies with age. Thus, operative realignment targets should account for age, with younger patients requiring more rigorous alignment objectives.
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    ItemOpen Access
    How Much Lumbar Lordosis does a Patient Need to Reach their Age-Adjusted Alignment Target? A Formulated Approach Predicting Successful Surgical Outcomes.
    (Global spine journal, 2022-04) McCarthy, Michael H; Lafage, Renaud; Smith, Justin S; Bess, Shay; Ames, Christopher P; Klineberg, Eric O; Kim, Han J; Shaffrey, Christopher I; Burton, Douglas C; Mundis, Gregory M; Gupta, Manish C; Schwab, Frank J; Lafage, Virginie; International Spine Study Group (ISSG)

    Study design

    Retrospective cohort study.

    Objectives

    Identify optimal lumbar lordosis in adult deformity correction to achieve age-adjusted targets and sustained alignment.

    Methods

    Surgical adult spinal deformity patients reaching an age-adjusted ideal alignment at one year were identified. Multilinear regression analysis was used to identify the relationship between regional curvatures (LL and TK) that enabled achievement of a given global alignment (T1 pelvic angle, TPA) based on pelvic incidence (PI).

    Results

    347 patients out of 1048 available reached their age-adjusted TPA within 5° (60-year-old, 72% women, body mass index 29 ± 6.2). They had a significant improvement in all sagittal parameters (except PI) from pre-operative baseline to 1 year following surgery (P < .001). Multilinear regression predicting L1-S1 based on TK, TPA, and PI demonstrated excellent results (R2 = .85). Simplification of the coefficients of prediction combined with a conversion to an age-based formula led to the following: LL = PI - 0.3TK - 0.5Age + 10. Internal validation of the formula led to a mean error of -.4°, and an absolute error of 5.0°. Internal validation on patients with an age-adjusted alignment revealed similar accuracy across the entire age-adjusted TPA spectrum (ranges of LL errors: ME = .2° to 1.7°, AE = 4.0° to 5.3°).

    Conclusion

    This study provides a simple guideline to identify the amount of LL needed to reach a given alignment (i.e., age-adjusted target) based on PI and associated TK. Implementation of this predictive formula during pre-operative surgical planning may help to reduce unexpected sub-optimal post-operative alignment outcomes.
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    ItemOpen Access
    Magnitude of preoperative cervical lordotic compensation and C2-T3 angle are correlated to increased risk of postoperative sagittal spinal pelvic malalignment in adult thoracolumbar deformity patients at 2-year follow-up.
    (The spine journal : official journal of the North American Spine Society, 2015-08) Passias, Peter G; Soroceanu, Alexandra; Scheer, Justin; Yang, Sun; Boniello, Anthony; Smith, Justin S; Protopsaltis, Themistocles; Kim, Han J; Schwab, Frank; Gupta, Munish; Klineberg, Eric; Mundis, Gregory; Lafage, Renaud; Hart, Robert; Shaffrey, Christopher; Lafage, Virginie; Ames, Christopher; International Spine Study Group

    Background context

    Cervical deformity (CD) is prevalent among patients with adult spinal deformity (ASD). The effect of baseline cervical alignment on achieving optimal thoracolumbar alignment in ASD surgery is unclear.

    Purpose

    This study assesses the relationship between preoperative (preop) cervical spinal parameters and global alignment after thoracolumbar ASD surgery at 2-year follow-up.

    Study design/setting

    This study is a retrospective review of a multicenter, prospective database.

    Patient sample

    Surgical ASD patients with 2-year follow-up and cervical X-rays were included.

    Outcome measures

    The outcome measures were radiographic parameters and self-reported health-related quality-of-life measures (Short-Form 36 [SF-36], Oswestry Disability Index [ODI], and Scoliosis Research Society 22 [SRS-22]).

    Methods

    Surgical ASD patients of 18 years and older with scoliosis greater than or equal to 20° and one of the following radiographic parameters were included: sagittal vertical axis (SVA) greater than or equal to 5 cm, pelvic tilt (PT) greater than or equal to 25°, or thoracic kyphosis (TK) greater than 60°. The SRS-Schwab sagittal modifiers (PT, global alignment, and pelvic incidence and lumbar lordosis [PI-LL]) were assessed at 2-year postoperatively as either normal ("0") or abnormal ("+" or "++"). Patients were classified in the aligned group (AG) or malaligned group (MG) at 2-year follow-up if all three sagittal modifiers were normal or abnormal, respectively. Patients were assessed for CD based on the following criteria: C2-C7 SVA greater than 4 cm, C2-C7 SVA less than 4 cm, cervical kyphosis (CL greater than 0), cervical lordosis (CL less than 0), any deformity (C2-C7 SVA greater than 4 cm or CL greater than 0), and both CD (C2-C7 SVA greater than 4 cm and CL greater than 0). Univariate testing was performed using t or chi-square test, looking at the following preop parameters: CD, C2-C7 SVA, C2-T3 SVA, CL, T1 slope (T1S), T1S-CL, C2-T3 angle, LL, TK, PT, C7-S1 SVA, and PI-LL.

    Results

    One hundred four patients met the initial inclusion criteria with 70 in the AG and 34 in MG. Preoperative, patients in the MG had a higher CL (11.7 vs. 4.9, p=.03), higher C2-T3 angle (13.59 vs 4.9 p=.01), higher PT (p<.0001), higher SVA (p<.0001), and higher PI-LL (p<.0001) compared with the AG. Interestingly, the prevalence of CD at baseline was similar for both groups. There was no statistically significant difference among groups in the amount of improvement more than 2 years on the ODI or the Physical Component Summary of SF-36.

    Conclusions

    Patients with sagittal spinal malalignment associated with significant cervical compensatory lordosis are at increased risk of realignment failure at 2-year follow-up. Assessment of the degree of cervical compensation may be helpful in preop evaluation to assist in realignment outcome prediction.
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    ItemOpen Access
    Total hospital costs of surgical treatment for adult spinal deformity: an extended follow-up study.
    (The spine journal : official journal of the North American Spine Society, 2014-10) McCarthy, Ian M; Hostin, Richard A; Ames, Christopher P; Kim, Han J; Smith, Justin S; Boachie-Adjei, Ohenaba; Schwab, Frank J; Klineberg, Eric O; Shaffrey, Christopher I; Gupta, Munish C; Polly, David W; International Spine Study Group

    Background context

    Whereas the costs of primary surgery, revisions, and selected complications for adult spinal deformity (ASD) have been individually reported in the literature, the total costs over several years after surgery have not been assessed. The determinants of such costs are also not well understood in the literature.

    Purpose

    This study analyzes the total hospital costs and operating room (OR) costs of ASD surgery through extended follow-up.

    Study design/setting

    Single-center retrospective analysis of consecutive surgical patients.

    Patient sample

    Four hundred eighty-four consecutive patients undergoing surgical treatment for ASD from January 2005 through January 2011 with minimum three levels fused.

    Outcome measures

    Costs were collected from hospital administrative data on the total hospital costs incurred for the operation and any related readmissions, expressed in 2010 dollars and discounted at 3.5% per year. Detailed data on OR costs, including implants and biologics, were also collected.

    Methods

    We performed a series of paired t tests and Wilcoxon signed-rank tests for differences in total hospital costs over different follow-up periods. The goal of these tests was to identify a time period over which average costs plateau and remain relatively constant over time. Generalized linear model regression was used to estimate the effect of patient and surgical factors on hospital inpatient costs, with different models estimated for different follow-up periods. A similar regression analysis was performed separately for OR costs and all other hospital costs.

    Results

    Patients were predominantly women (n=415 or 86%) with an average age of 48 (18-82) years and an average follow-up of 4.8 (2-8) years. Total hospital costs averaged $120,394, with primary surgery averaging $103,143 and total readmission costs averaging $67,262 per patient with a readmission (n=130 or 27% of all patients). Operating room costs averaged $70,514 per patient, constituting the majority (59%) of total hospital costs. Average total hospital costs across all patients significantly increased (p<.01) after primary surgery, from $111,807 at 1-year follow-up to $126,323 at 4-year follow-up. Regression results also revealed physician preference as the largest determinant of OR costs, accounting for $14,780 of otherwise unexplained OR cost differences across patients, with no significant physician effects on all other non-OR costs (p<.05).

    Conclusions

    The incidence of readmissions increased the average cost of ASD surgery by more than 70%, illustrating the financial burden of revisions/reoperations; however, the cost burden resulting from readmissions appeared to taper off within 5 years after surgery. The estimated impact of physician preference on OR costs also highlights the variation in current practice and the opportunity for large cost reductions via a more standardized approach in the use of implants and biologics.
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    ItemOpen Access
    Under Correction of Sagittal Deformities Based on Age-adjusted Alignment Thresholds Leads to Worse Health-related Quality of Life Whereas Over Correction Provides No Additional Benefit.
    (Spine, 2018-03) Scheer, Justin K; Lafage, Renaud; Schwab, Frank J; Liabaud, Barthelemy; Smith, Justin S; Mundis, Gregory M; Hostin, Richard; Shaffrey, Christopher I; Burton, Douglas C; Hart, Robert A; Kim, Han J; Bess, Shay; Gupta, Munish; Lafage, Virginie; Ames, Christopher P; International Spine Study Group

    Study design

    Retrospective review of prospectively-collected database.

    Objective

    This study aims to compare 2-year clinical outcomes of patients who underwent surgical reconstructions based on their achievement to age-adjusted alignment ideals.

    Summary of background data

    Recent research in sagittal plane has proposed age-adjusted alignment thresholds. However, the impact of these thresholds on postoperative health-related quality of life (HRQOL) is yet to be investigated.

    Methods

    Patients were included if they were more than 18-years old and underwent surgical correction of adult spinal deformity with a complete 2-year follow-up. Patients were stratified into three groups based on achievement of age-adjusted thresholds in pelvic tilt (PT), pelvic incidence minus lumbar lordosis (PI-LL), and sagittal vertical axis (SVA). First group included patients who reached the exact age-adjusted threshold ± 10 years (MATCHED), other two groups included patients who were over corrected (OVER), and under corrected (UNDER). Clinical outcomes including actual value and offset from age-adjusted Oswestry Disability Index, Short-Form-36 (SF-36) -physical component summary, and Scoliosis Research Society-22r (SRS-22r) were compared between groups at 2 years follow-up.

    Results

    A total of 343 patients (mean, 57 yrs and 83% females) were included. Sagittal profile of the population was: PT = 23.6°, SVA = 65.8 mm, and PI-LL = 15.6°. At 2-year follow-up, there was significant improvement in all sagittal modifiers with 25.7%, 24.3%, and 33.1% of the patients matching their age alignment targets in terms of PT, PI-LL, and SVA, respectively. For PT and PI-LL, the three groups (MATCHED, OVER, and UNDER) had comparable values and offsets from age-adjusted patient reported outcome. However, for SVA groups, patients in UNDER had significantly worse HRQOL than the two other groups. Patients in PT, PI-LL, and SVA UNDER groups were significantly younger than the other groups, P < 0.05.

    Conclusion

    At 2 years after adult spinal deformity surgical treatment, only 24.3% to 33.1% of the patients reached age-adjusted alignment thresholds. Those under corrected in SVA demonstrated worse clinical outcomes. No significant improvements were found between matched and overcorrected patients, with overcorrection being an established risk for proximal junctional kyphosis. These results further emphasize the need for patient specific operative planning.

    Level of evidence

    3.