Cervical, Thoracic, and Spinopelvic Compensation After Proximal Junctional Kyphosis (PJK): Does Location of PJK Matter?

Study Design: Retrospective case series. Objective: Compensatory changes above a proximal junctional kyphosis (PJK) have not been defined. Understanding these mechanisms may help determine optimal level selection when performing revision for PJK. This study investigates how varying PJK location changes proximal spinal alignment. Methods: Patients were grouped by upper instrumented vertebrae (UIV): lower thoracic (LT; T8-L1) or upper thoracic (UT; T1-7). Alignment parameters were compared. Correlation analysis was performed between PJK magnitude and global/cervical alignment. Results: A total of 369 patients were included; mean age of 63 years, body mass index 28, and 81% female, LT (n = 193) versus UT (n = 176). The rate of radiographic PJK was 49%, higher in the LT group (55% vs 42%, P = .01). The UT group displayed significant differences in all cervical radiographic parameters ( P < .05) between PJK versus non-PJK patients, while the LT group displayed significant differences in T1S and C2-T3 sagittal vertical axis (SVA) (CTS). In comparing UT versus LT patients, UT had more posterior global alignment (smaller TPA [T1 pelvic angle], SVA, and larger PT [pelvic tilt]) and larger anterior cervical alignment (greater cSVA [cervical SVA], T1S-CL [T1 slope–cervical lordosis] mismatch, CTS) compared to LT. Correlation analysis of PJK magnitude and location demonstrated a correlation with increases in CL, T1S, and CTS in the UT group. In the LT group, PT increased with PJK angle ( r = 0.17) and no significant correlations were noted to SVA, cSVA, or T1S-CL. Conclusions: PJK location influences compensation mechanisms of the cervical and thoracic spine. LT PJK results in increased PT and CL with decreased CTS. UT PJK increases CL to counter increases in T1S with continued T1S-CL mismatch and elevated cSVA.

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The utility of supine radiographs in the assessment of thoracic flexibility and risk of proximal junctional kyphosis

Journal of Neurosurgery Spine ◽

10.3171/2020.11.spine201565 ◽

2021 ◽

pp. 1-7

Author(s):

Francis Lovecchio ◽

Renaud Lafage ◽

Jonathan Charles Elysee ◽

Alex Huang ◽

Bryan Ang ◽

...

Keyword(s):

Thoracic Spine ◽

Lumbar Lordosis ◽

Pelvic Tilt ◽

Pelvic Incidence ◽

Vertical Axis ◽

Control Analysis ◽

Proximal Junctional Kyphosis ◽

Sagittal Vertical Axis ◽

Significant Difference ◽

Junctional Kyphosis

OBJECTIVE Supine radiographs have successfully been used for preoperative planning of lumbar deformity corrections. However, they have not been used to assess thoracic flexibility, which has recently garnered attention as a potential contributor to proximal junctional kyphosis (PJK). The purpose of this study was to compare supine to standing radiographs to assess thoracic flexibility and to determine whether thoracic flexibility is associated with PJK. METHODS A retrospective study was conducted of a single-institution database of patients with adult spinal deformity (ASD). Sagittal alignment parameters were compared between standing and supine and between pre- and postoperative radiographs. Thoracic flexibility was determined as the change between preoperative standing thoracic kyphosis (TK) and preoperative supine TK, and these changes were measured over the overall thoracic spine and the fused portion of the thoracic spine (i.e., TK fused). A case-control analysis was performed to compare thoracic flexibility between patients with PJK and those without (no PJK). The cohort was also stratified into three groups based on thoracic flexibility: kyphotic change (increased TK), lordotic change (decreased TK), and no change. The PJK rate was compared between the cohorts. RESULTS A total of 101 patients (mean 63 years old, 82.2% female, mean BMI 27.4 kg/m2) were included. Preoperative Scoliosis Research Society–Schwab ASD classification showed moderate preoperative deformity (pelvic tilt 27.7% [score ++]; pelvic incidence–lumbar lordosis mismatch 44.6% [score ++]; sagittal vertical axis 42.6% [score ++]). Postoperatively, the average offset from age-adjusted alignment goals demonstrated slight overcorrection in the study sample (−8.5° ± 15.6° pelvic incidence–lumbar lordosis mismatch, −29.2 ± 53.1 mm sagittal vertical axis, −5.4 ± 10.8 pelvic tilt, and −7.6 ± 11.7 T1 pelvic angle). TK decreased between standing and supine radiographs and increased postoperatively (TK fused: −25.3° vs −19.6° vs −29.9°; all p < 0.001). The overall rate of radiographic PJK was 23.8%. Comparisons between PJK and no PJK demonstrated that offsets from age-adjusted alignment goals were similar (p > 0.05 for all). There was a significant difference in the PJK rate when stratified by thoracic flexibility cohorts (kyphotic: 0.0% vs no change: 18.4% vs lordotic: 35.0%; p = 0.049). Logistic regression revealed thoracic flexibility (p = 0.045) as the only independent correlate of PJK. CONCLUSIONS Half of patients with ASD experienced significant changes in TK during supine positioning, a quality that may influence surgical strategy. Increased thoracic flexibility is associated with PJK, possibly secondary to fusing the patient’s spine in a flattened position intraoperatively.

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Beyond Pelvic Incidence–Lumbar Lordosis Mismatch: The Importance of Assessing the Entire Spine to Achieve Global Sagittal Alignment

Global Spine Journal ◽

10.1177/2192568217699405 ◽

2017 ◽

Vol 7 (6) ◽

pp. 536-542 ◽

Cited By ~ 8

Author(s):

Robert K. Merrill ◽

Jun S. Kim ◽

Dante M. Leven ◽

Joung Heon Kim ◽

Samuel K. Cho

Keyword(s):

Lumbar Lordosis ◽

Pelvic Incidence ◽

Adult Spinal Deformity ◽

Case Series ◽

Vertical Axis ◽

Retrospective Case ◽

Sagittal Vertical Axis ◽

Global Sagittal Alignment ◽

Sagittal Parameters ◽

Combined Parameters

Study Design: Retrospective case series. Objective: To investigate which sagittal parameters contribute to a normal sagittal vertical axis (SVA) when there is a pelvic incidence-lumbar lordosis (PI-LL) mismatch >10° following adult spinal deformity (ASD) correction. Methods: We performed a retrospective review of ASD patients with >5 levels fused. Sagittal measurements between cohorts of postoperative PI-LL >10° and PI-LL<10° were compared. We correlated SVA to pelvic tilt (PT), thoracic kyphosis (TK), PI-LL, cervical lordosis (CL), and correlated the pre- to postoperative change in SVA to change in PT, change in TK, change in PI-LL, and change in CL. We also correlated SVA and the change in SVA to combined parameters of ((PI-LL) − PT + TK). Results: We analyzed 52 patients with a mean age of 59 ± 16 years. In patients with a postoperative SVA <5cm, a smaller TK was seen when PI-LL >10° than when PI-LL<10° (15.45° vs 33.04°, P = .0004). Additionally, PT was larger when PI-LL >10° than when PI-LL <10° (25.73° vs 19.07°, P = .006). SVA correlated better with ((PI-LL) − PT + TK) ( R2 = 0.51) than with PI-LL alone ( R2 = 0.33). Lastly, there was no significant correlation between change in pre- to postoperative SVA with change in TK for all cases ( P = .73), but in cases where change in PI-LL was <10°, there was a significant correlation between change in TK and change in SVA ( P = .009). Conclusion: Our results demonstrate that PT and TK, and not just PI-LL, play an important role in maintaining sagittal balance when there is a PI-LL mismatch >10°.

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Significance of various risk factors for proximal junctional kyphosis and instability of instrumentation in surgical treatment for adult spinal deformities

Hirurgiâ pozvonočnika ◽

10.14531/ss2021.1.14-23 ◽

2021 ◽

Vol 18 (1) ◽

pp. 14-23

Author(s):

I. V. Basankin ◽

D. A. Ptashnikov ◽

S. V. Masevnin ◽

A. A. Afaunov ◽

A. A. Giulzatyan ◽

...

Keyword(s):

Risk Factors ◽

Surgical Treatment ◽

Lumbar Lordosis ◽

Significant Risk ◽

Vertical Axis ◽

Type I ◽

Proximal Junctional Kyphosis ◽

Sagittal Vertical Axis ◽

Transpedicular Instrumentation ◽

Junctional Kyphosis

Objective. To analyze the significance of the influence of various risk factors on the development of proximal junctional kyphosis (PJK) and instability of instrumentation.Material and Methods. The results of surgical treatment of 382 patients with scoliotic deformities of the lumbar spine of type I and IIIb according to Aebi were analyzed. Patients were operated on through the posterior approach using the TLIF-PLIF technique with extended rigid transpedicular instrumentation. Potential risk factors influencing the development of proximal junctional kyphosis and instability of instrumentation were analyzed.Results. It was found that only three risk factors significantly affect the development of PJK: correction of lumbar lordosis more than 30° (p = 0.036) increases the likelihood of its development by 1.5 times, osteoporosis (p = 0.001) – by 2.5 times, and proximal junctionalangle ≥10° (p = 0.001) – by 3.5 times. Three factors showed a statistically significant effect on the incidence of instrumentation instability: correction of lumbar lordosis more than 30° (p = 0.034) increases the likelihood of its occurrence by 1.7 times, osteoporosis (p = 0.018) – by 1.8 times, and deviation of the sagittal vertical axis by more than 50 mm (p = 0.001) – by 3.3 times.Conclusion. The most significant risk factors for the occurrence of PJK and instability of instrumentation are osteoporosis, correction of lumbar lordosis more than 30°, an increase in the proximal junctional angle ≥10°, and an anterior deviation of sagittal vertical axis more than 50 mm. Consideration of these factors in the preoperative period, as well as during surgery, can decrease likelihood of the occurrence of PJK and instability of instrumentation.

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Risk factor analysis of proximal junctional kyphosis after posterior osteotomy in patients with ankylosing spondylitis

Journal of Neurosurgery Spine ◽

10.3171/2017.11.spine17228 ◽

2018 ◽

Vol 29 (1) ◽

pp. 75-80 ◽

Cited By ~ 8

Author(s):

Tianhao Wang ◽

Yongfei Zhao ◽

Yan Liang ◽

Haocong Zhang ◽

Zheng Wang ◽

...

Keyword(s):

Risk Factors ◽

Ankylosing Spondylitis ◽

Oswestry Disability Index ◽

Vertical Axis ◽

Pedicle Subtraction Osteotomy ◽

Proximal Junctional Kyphosis ◽

Sagittal Vertical Axis ◽

Radiographic Measurements ◽

Lowest Instrumented Vertebra ◽

Junctional Kyphosis

OBJECTIVEThe aim of this paper was to analyze the incidence and risk factors of proximal junctional kyphosis (PJK) in patients with ankylosing spondylitis (AS) who underwent pedicle subtraction osteotomy.METHODSThe records of 83 patients with AS and thoracolumbar kyphosis who underwent surgery at the authors’ institution between 2007 and 2013 were reviewed. The patients were divided into 2 groups based on the presence or absence of PJK. The radiographic measurements, including proximal junctional angle (PJA), sagittal parameters, and pelvic parameters of these 2 groups, were compared at different time points: before surgery and 2 weeks, 12 months, and 2 years after surgery. Oswestry Disability Index scores were also evaluated.RESULTSOverall, 14.5% of patients developed PJK. Before surgery, the mean PJAs in the 2 groups were 13.6° and 8.5°, respectively (p = 0.008). There were no significant differences in age, sex, and body mass index between groups. Patients with PJK had a larger thoracolumbar kyphotic angle (50.8° ± 12.6°) and a greater sagittal vertical axis (21.7 ± 4.3 cm) preoperatively than those without PJK. The proportion of patients with PJK whose fusion extended to the sacrum was 41.2% (7/17), which is significantly greater than the proportion of patients with PJK whose lowest instrumented vertebra was above the sacrum. Oswestry Disability Index scores did not significantly increase in the PJK group compared with the non-PJK group.CONCLUSIONSThe authors found that PJK occurs postoperatively in patients with AS with an incidence of 14.5%. Risk factors of PJK include larger preoperative sagittal vertical axis, PJA, and osteotomy angle. Reducing the osteotomy angle in some severe cases and extending fusion to a higher, flatter level would be also beneficial in decreasing the risk of PJK.

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Does Minimally Invasive Percutaneous Posterior Instrumentation Reduce Risk of Proximal Junctional Kyphosis in Adult Spinal Deformity Surgery? A Propensity-Matched Cohort Analysis

Neurosurgery ◽

10.1227/neu.0000000000001002 ◽

2015 ◽

Vol 78 (1) ◽

pp. 101-108 ◽

Cited By ~ 27

Author(s):

◽

Praveen V. Mummaneni ◽

Paul Park ◽

Kai-Ming Fu ◽

Michael Y. Wang ◽

...

Keyword(s):

Minimally Invasive ◽

Pedicle Screw ◽

Posterior Instrumentation ◽

Vertical Axis ◽

Screw Placement ◽

Proximal Junctional Kyphosis ◽

Pedicle Screw Placement ◽

Sagittal Vertical Axis ◽

Spinal Deformity Surgery ◽

Junctional Kyphosis

Abstract BACKGROUND: Proximal junctional kyphosis (PJK) is a known complication after spinal deformity surgery. One potential cause is disruption of posterior muscular tension band during pedicle screw placement. OBJECTIVE: To investigate the effect of minimally invasive surgery (MIS) on PJK. METHODS: A multicenter database of patients who underwent deformity surgery was propensity matched for pelvic incidence (PI) to lumbar lordosis (LL) mismatch and change in LL. Radiographic PJK was defined as proximal junctional angle >10°. Sixty-eight patients made up the circumferential MIS (cMIS) group, and 68 were in the hybrid (HYB) surgery group (open screw placement). RESULTS: Preoperatively, there was no difference in age, body mass index, PI-LL mismatch, or sagittal vertical axis. The mean number of levels treated posteriorly was 4.7 for cMIS and 8.2 for HYB (P < .001). Both had improved LL and PI-LL mismatch postoperatively. Sagittal vertical axis remained physiological for the cMIS and HYB groups. Oswestry Disability Index scores were significantly improved in both groups. Radiographic PJK developed in 31.3% of the cMIS and 52.9% of the HYB group (P = .01). Reoperation for PJK was 4.5% for the cMIS and 10.3% for the HYB group (P = .20). Subgroup analysis for patients undergoing similar levels of posterior instrumentation in the cMIS and HYB groups found a PJK rate of 48.1% and 53.8% (P = .68) and a reoperation rate of 11.1% and 19.2%, respectively (P = .41). Mean follow-up was 32.8 months. CONCLUSION: Overall rates of radiographic PJK and reoperation for PJK were not significantly decreased with MIS pedicle screw placement. However, a larger comparative study is needed to confirm that MIS pedicle screw placement does not affect PJK.

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Posterior Displacement of L1 May be a Risk Factor for Proximal Junctional Kyphosis After Adult Spinal Deformity Correction

Global Spine Journal ◽

10.1177/21925682211015651 ◽

2021 ◽

pp. 219256822110156

Author(s):

Zhuo Xi ◽

Ping-Guo Duan ◽

Praveen V. Mummaneni ◽

Jinping Liu ◽

Jeremy M.V. Guinn ◽

...

Keyword(s):

Thoracic Spine ◽

Spinal Deformity ◽

Adult Spinal Deformity ◽

Deformity Correction ◽

Vertical Axis ◽

Proximal Junctional Kyphosis ◽

Sagittal Vertical Axis ◽

Posterior Displacement ◽

Increased Risk ◽

Junctional Kyphosis

Study Design: Retrospective cohort study. Objective: Overcorrection in adult spinal deformity (ASD) surgery may lead to proximal junctional kyphosis (PJK) because of posterior spinal displacement. The aim of this paper is to determine if the L1 position relative to the gravity line (GL) is associated with PJK. Methods: ASD patients fused from the lower thoracic spine to sacrum by 4 spine surgeons at our hospital were retrospectively studied. Lumbar-only and upper thoracic spine fusions were excluded. Spinopelvic parameters, the L1 plumb line (L1PL), L1 distance to the GL (L1-GL), and Roussouly type were measured. Results: One hundred fourteen patients met inclusion criteria (63 patients with PJK, 51 without). Mean age and follow up was 65.51 and 3.39 years, respectively. There was no difference between the PJK and the non-PJK groups in baseline demographics, pre-operative and immediate post-operative pelvic incidence-lumbar lordosis mismatch, sagittal vertical axis, or coronal Cobb. The immediate postoperative L1-GL was -7.24 cm in PJK and -3.45 cm in non-PJK ( P < 0.001), L1PL was 1.71 cm in PJK and 3.07 cm in non-PJK ( P = 0.004), and PT (23.76° vs 18.90°, P = 0.026) and TK (40.56° vs 31.39°, P < 0.001) were larger in PJK than in non-PJK. After univariate and multivariate analyses, immediate postoperative TK and immediate postoperative L1-GL were independent risk factors for PJK without collinearity. Conclusions: A dorsally displaced L1 relative to the GL was associated with an increased risk of PJK after ASD surgery. The postoperative L1-GL distance may be a factor to consider during ASD surgery.

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Is Sacral Extension a Risk Factor for Early Proximal Junctional Kyphosis in Adult Spinal Deformity Surgery?

Asian Spine Journal ◽

10.31616/asj.2018.0314 ◽

2020 ◽

Vol 14 (2) ◽

pp. 212-219

Author(s):

Sebastian Decker ◽

Renaud Lafage ◽

Christian Krettek ◽

Robert Hart ◽

Christopher Ames ◽

...

Keyword(s):

Spinal Deformity ◽

Adult Spinal Deformity ◽

Vertical Axis ◽

Proximal Junctional Kyphosis ◽

Sagittal Vertical Axis ◽

Increased Risk ◽

Spinal Deformity Surgery ◽

One Year ◽

Junctional Kyphosis

Study Design: Retrospective cohort study.Purpose: To investigate the role of sacral extension (SE) for the development of proximal junctional kyphosis (PJK) in adult spinal deformity (ASD) surgery.Overview of Literature: The development of PJK is multifactorial and different risk factors have been identified. Of these, there is some evidence that SE also affects the development of PJK, but data are insufficient. Methods: Using a combined database comprising two propensity-matched groups of fusions following ASD surgery, one with fixation to S1 or S1 and the ilium (SE) and one without SE but with a lower instrumented vertebra of L5 or higher (lumbar fixation, LF), PJK and the role of further parameters were analyzed. The propensity-matched variables included age, the upper-most instrumented vertebra (UIV), preoperative sagittal alignment, and the baseline to one year change of the sagittal alignment.Results: Propensity matching led to two groups of 89 patients each. The UIV, pelvic incidence minus lumbar lordosis, sagittal vertical axis, pelvic tilt, age, and body mass index were similar in both groups (p >0.05). The incidence of PJK at postoperative one year was similar for SE (30.3%) and LF (22.5%) groups (p =0.207). The PJK angle was comparable (p =0.963) with a change of −8.2° (SE) and −8.3° (LF) from the preoperative measures (p =0.954). A higher rate of PJK after SE (p =0.026) was found only in the subgroup of patients with UIV levels between T9 and T12.Conclusions: Instrumentation to the sacrum with or without iliac extension did not increase the overall risk of PJK. However, an increased risk for PJK was found after SE with UIV levels between T9 and T12.

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Cervical Alignment Changes in Patients Developing Proximal Junctional Kyphosis Following Surgical Correction of Adult Spinal Deformity

Neurosurgery ◽

10.1093/neuros/nyx479 ◽

2017 ◽

Vol 83 (4) ◽

pp. 675-682 ◽

Cited By ~ 5

Author(s):

Peter G Passias ◽

Samantha R Horn ◽

Cyrus M Jalai ◽

Subaraman Ramchandran ◽

Gregory W Poorman ◽

...

Keyword(s):

Spinal Deformity ◽

Adult Spinal Deformity ◽

Surgical Correction ◽

Proximal Junctional Kyphosis ◽

Cervical Alignment ◽

Junctional Kyphosis

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Diagnostic Accuracy of Magnetic Resonance Imaging for Sagittal Cervical Spine Alignment: A Retrospective Cohort Study

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph182413033 ◽

2021 ◽

Vol 18 (24) ◽

pp. 13033

Author(s):

Chahyun Oh ◽

Chan Noh ◽

Jieun Lee ◽

Sangmin Lee ◽

Boohwi Hong ◽

...

Keyword(s):

Cobb Angle ◽

Rotation Angle ◽

Vertical Axis ◽

Resonance Imaging ◽

Sagittal Vertical Axis ◽

Predictive Values ◽

Cervical Alignment ◽

The Subject ◽

Cervical Spine Alignment ◽

Mri Measurements

(1) Background: Although radiography performed on the subject in an upright position is considered the standard method for assessing sagittal cervical alignment, it is frequently determined, or reported, based on MRI performed on the subject in a supine position. (2) Methods: Cervical alignment observed in both imaging modalities was assessed using four methods: the C2-7 Cobb angle, the absolute rotation angle (ARA), Borden’s method, and the sagittal vertical axis (SVA). Cervical alignment was determined (lordosis, kyphosis, and straight) based on radiography. Then, the diagnostic cut-off values for the MRI images and their corresponding diagnostic accuracies were assessed. (3) Results: The analysis included 142 outpatients. The determined diagnostic cut-off values for lordosis, using three measurements (Cobb angle, ARA, and Borden’s method), were −8.5°, −12.5°, and 3.5 mm, respectively, and the cut-off values for kyphosis were −4.5°, 0.5°, and −1.5 mm, respectively. The cut-off value for SVA > 40 mm was 19.5 mm. The Cobb angle, ARA, and Borden’s method, on MRI, showed high negative predictive values for determining kyphosis. The SVA on MRI measurements also showed high negative predictive values for determining >40 mm. (4) Conclusions: MRI measurements may be predictive of cervical alignment, especially for the exclusion of kyphosis and SVA > 40 mm. However, caution is needed in the other determinations using MRI, as their accuracies are limited.

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Outcomes of Surgical Treatment for One Hundred Thirty-Eight Patients With Severe Sagittal Deformity at a Minimum 2-Year Follow-up: A Case Series

Operative Neurosurgery ◽

10.1093/ons/opab153 ◽

2021 ◽

Author(s):

Justin K Scheer ◽

Lawrence G Lenke ◽

Justin S Smith ◽

Darryl Lau ◽

Peter G Passias ◽

...

Keyword(s):

Adult Spinal Deformity ◽

Case Series ◽

Major Complication ◽

Vertical Axis ◽

Surgical Correction ◽

Complication Rates ◽

Sagittal Vertical Axis ◽

Estimated Blood Loss ◽

Sagittal Deformity

Abstract BACKGROUND Operative treatment of adult spinal deformity (ASD) can be very challenging with high complication rates. It is well established that patients benefit from such treatment; however, the surgical outcomes for patients with severe sagittal deformity have not been reported. OBJECTIVE To report the outcomes of patients undergoing surgical correction for severe sagittal deformity. METHODS Retrospective review of a prospective, multicenter ASD database. Inclusion criteria: operative patients age ≥18, sagittal vertical axis (SVA) ≥15 cm, mismatch between pelvic incidence and lumbar lordosis (PI-LL) ≥30°, and/or lumbar kyphosis ≥5° with minimum 2 yr follow-up. Health-related quality of life (HRQOL) scores including minimal clinically important difference (MCID)/substantial clinical benefit (SCB), sagittal and coronal radiographic values, demographic, frailty, surgical, and complication data were collected. Comparisons between 2 yr postoperative and baseline HRQOL/radiographic data were made. P < .05 was significant. RESULTS A total of 138 patients were included from 502 operative patients (54.3% Female, Average (Avg) age 63.3 ± 11.5 yr). Avg operating room (OR) time 386.2 ± 136.5 min, estimated blood loss (EBL) 1829.8 ± 1474.6 cc. A total of 71(51.4%) had prior fusion. A total of 89.9% were posterior fusion only. Mean posterior levels fused 11.5 ± 4.1. A total of 44.9% had a 3-column osteotomy. All 2 yr postoperative radiographic parameters were significantly improved compared to baseline (P < .001 for all). All 2yr HRQOL measures were significantly improved compared to baseline (P < .004 for all). A total of 46.6% to 73.8% of patients met either MCID/SCB for all HRQOL. A total of 74.6% of patients had at least 1 complication, 11.6% had 4 or more complications, 33.3% had minimum 1 major complication, and 42(30.4%) had a postop revision. CONCLUSION Patients with severe sagittal malalignment benefit from surgical correction at 2 yr postoperative both radiographically and clinically despite having a high complication rate.

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