Mechanical complications and patient-reported outcome measures associated with high pelvic incidence and persistent pelvic retroversion: the Roussouly “false type 2” profile

Thamrong Lertudomphonwanit Department of Orthopaedic Surgery, Faculty of Medicine, Ramathibodi Hospital, Mahidol University, Bangkok, Thailand;

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Munish C. Gupta Department of Orthopedic Surgery, University of California, San Francisco, California;

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Alekos A. Theologis Department of Orthopedic Surgery, Washington University, St. Louis, Missouri;

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Julio J. Jauregui Department of Orthopedic Surgery, University of California, San Francisco, California;

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Lawrence G. Lenke Department of Orthopedic Surgery, Columbia University Medical Center, New York, New York; and

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Keith H. Bridwell Department of Orthopedic Surgery, University of California, San Francisco, California;

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James P. Wondra II Department of Orthopedic Surgery, University of California, San Francisco, California;

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Michael P. Kelly Department of Orthopedic Surgery, Rady Children’s Hospital, University of California, San Diego, California

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OBJECTIVE

The objective of this paper was to report mechanical complications and patient-reported outcome measures (PROMs) for adult spinal deformity (ASD) patients with a Roussouly "false type 2" (FT2) profile.

METHODS

ASD patients treated from 2004 to 2014 at a single center were identified. Inclusion criteria were pelvic incidence ≥ 60° and a minimum 2-year follow-up. FT2 was defined as a high postoperative pelvic tilt (PT), as defined by the Global Alignment and Proportion target, and thoracic kyphosis < 30°. Mechanical complications, defined as proximal junctional kyphosis (PJK) and/or instrumentation failure, were determined and compared. Scoliosis Research Society–22r (SRS-22r) scores were compared between groups.

RESULTS

Ninety-five patients (normal PT [NPT] group 49, FT2 group 46) who met the inclusion criteria were identified and studied. Most surgeries were revisions (NPT group 30 [61%], FT2 group 30 [65%]), and most were performed via a posterior-only approach (86%) (mean ± SD 9.6 ± 5 levels). Proximal junctional angles increased after surgery in both groups, without differences between groups. Neither rates of radiographic PJK (p = 0.10), revision for PJK (p = 0.45), nor revision for pseudarthrosis (p = 0.66) were different between groups. There were no differences between groups for SRS-22r domain scores or subscores.

CONCLUSIONS

In this single-center experience, patients with high pelvic incidence fixed with persistent lumbopelvic parameter mismatch and engaged compensatory mechanisms (Roussouly FT2) had mechanical complications and PROMs not different from those with normalized alignment parameters. Compensatory PT may be acceptable in some cases of ASD surgery.

ABBREVIATIONS

ASD = adult spinal deformity; FT2 = false type 2; GAP = Global Alignment and Proportion; HRQOL = health-related quality of life; LL = lumbar lordosis; NPT = normal PT; PI = pelvic incidence; PJA = proximal junctional angle; PJK = proximal junctional kyphosis; PROM = patient-reported outcome measure; PT = pelvic tilt; rhBMP-2 = recombinant human bone morphogenetic protein–2; SRS-22r = Scoliosis Research Society–22r; SVA = sagittal vertical axis; TK = thoracic kyphosis; UIV = upper instrumented vertebra.

OBJECTIVE

The objective of this paper was to report mechanical complications and patient-reported outcome measures (PROMs) for adult spinal deformity (ASD) patients with a Roussouly "false type 2" (FT2) profile.

METHODS

ASD patients treated from 2004 to 2014 at a single center were identified. Inclusion criteria were pelvic incidence ≥ 60° and a minimum 2-year follow-up. FT2 was defined as a high postoperative pelvic tilt (PT), as defined by the Global Alignment and Proportion target, and thoracic kyphosis < 30°. Mechanical complications, defined as proximal junctional kyphosis (PJK) and/or instrumentation failure, were determined and compared. Scoliosis Research Society–22r (SRS-22r) scores were compared between groups.

RESULTS

Ninety-five patients (normal PT [NPT] group 49, FT2 group 46) who met the inclusion criteria were identified and studied. Most surgeries were revisions (NPT group 30 [61%], FT2 group 30 [65%]), and most were performed via a posterior-only approach (86%) (mean ± SD 9.6 ± 5 levels). Proximal junctional angles increased after surgery in both groups, without differences between groups. Neither rates of radiographic PJK (p = 0.10), revision for PJK (p = 0.45), nor revision for pseudarthrosis (p = 0.66) were different between groups. There were no differences between groups for SRS-22r domain scores or subscores.

CONCLUSIONS

In this single-center experience, patients with high pelvic incidence fixed with persistent lumbopelvic parameter mismatch and engaged compensatory mechanisms (Roussouly FT2) had mechanical complications and PROMs not different from those with normalized alignment parameters. Compensatory PT may be acceptable in some cases of ASD surgery.

In Brief

Cohorts of patients with high pelvic incidence were studied to examine mechanical complications and patient-reported outcomes after spinal fusion. Neither proximal junctional kyphosis nor pseudarthrosis rates were different between those fixed with appropriate lordosis and those with high pelvic tilt (Roussouly false type 2). Patient-reported outcomes were not different. In some patients, less surgery to allow for retroversion and horizontal gaze may be appropriate and durable.

Appropriate restoration of sagittal alignment is a tenet of surgery for adult spinal deformity (ASD). Prior studies have suggested poor results with lower health-related quality of life (HRQOL) and failures due to proximal junctional kyphosis (PJK) and pseudarthrosis in patients with global sagittal imbalance and lumbopelvic malalignment.17 The Global Alignment and Proportion (GAP) score has defined regional alignment goals to minimize the risks of pseudarthrosis and junctional failure.1 Reestablishment of lumbopelvic harmony can be challenging in patients with high pelvic incidence (PI; Roussouly types 3 and 4), and compensatory mechanisms in these patients may result in satisfactory global sagittal alignment in the setting of persistent lumbopelvic malalignment.8 Recent works have suggested that postoperative high pelvic tilt (PT) is associated with an increased risk of PJK and pseudarthrosis.1,7

Roussouly defined "false type 2" (FT2) as occurring in a patient with high PI fixed with inadequate lumbar lordosis (LL) and compensatory pelvic retroversion (high PT) and thoracic flattening to maintain horizontal gaze. This alignment may deceive surgeons when patients stand upright, and normalization of sagittal parameters may require more invasive interventions. The goal of this study was to investigate the rates of PJK and rod fracture after ASD surgery and to compare patient-reported outcome measures (PROMs) for patients whose alignment was restored to normal and patients fixed with an FT2 profile.

Methods

After approval from the institutional review board, medical records and radiographs of adult patients who underwent posterior spinal instrumented fusions for thoracolumbar spinal deformity from 2004 to 2014 at a single center were reviewed. The inclusion criteria were instrumentation to the pelvis, ≥ 5 levels of posterior spinal instrumented fusions, and > 24 months of follow-up. To define an FT2 profile, we included patients with PI ≥ 60°, a high postoperative PT, and thoracic kyphosis (TK) < 30°. High PT was defined as > 5° greater than the ideal PT per GAP score.1 For this study, we chose to calculate the ideal PT rather than choose a fixed value because PT increases with increasing PI in a normal, healthy population. Patients with PI > 60°, normal PT (NPT), and TK ≥ 30° formed a comparison group (NPT group).

Demographics and radiographic parameters (i.e., C7 sagittal vertical axis [SVA], PI, PT, LL, TK, proximal junctional angle [PJA], maximum coronal Cobb angle, and central sacral vertical line) at baseline and at follow-up were analyzed for each patient. Surgical details, including estimated blood loss, operative time, surgical approach, and number of levels instrumented/fused, were determined. Surgical techniques, including rod material, number of rods used, three-column osteotomies, interbody use, interbody type, recombinant bone morphogenetic protein (rhBMP-2; Medtronic) use, and type of bone grafts, were recorded. Mechanical failures counted were PJK as defined by Glattes et al. (increase in kyphotic angle from the upper instrumented vertebra [UIV] + 2 and UIV of at least 10°), rod fracture, and associated revision operations.9 Scoliosis Research Society–22r (SRS-22r) scores were collected at baseline, 1 year, and 2 years.

Statistical Analysis

Paired t-tests were used to compare within-group continuous data. PROMs are reported with median values and interquartile ranges. Comparisons of PROMs between groups were performed with the Mann-Whitney U-test for nonparametric data. This is an exploratory study, and no corrections for multiple comparisons were made. A p value < 0.05 determined statistical significance. All analyses were performed using IBM SPSS version 28.0 (IBM Corp.).

Results

Demographic data are summarized in Table 1. Ninety-five patients (NPT group 49, FT2 group 46) were analyzed. The majority were female (NPT group 80%, FT2 group 89%; p = 0.2). The average ages were not different (NPT group 56.0 years, FT2 group 58.9 years; p = 0.15). The mean ± SD follow-up was 57 ± 28 months (range 13–138 months). FT2 patients had higher baseline sagittal plane deformity but a small difference in C7 SVA at the last follow-up (NPT group 4.0 ± 4.2, FT2 group 5.4 ± 4.5; p = 0.013; Table 2). Coronal balance was not different at any point. Radiographic data are found in Table 2. A representative case illustration of FT2 is shown in Fig. 1.

TABLE 1.

Demographic data for 95 patients

NPT Group (n = 49)FT2 Group (n = 46)p Value
Female sex39 (80)41 (89)0.20
Age, yrs56.0 ± 10.358.9 ± 9.50.15
BMI26.7 ± 4.627.5 ± 4.20.42
FU, mos63 ± 3254 ± 250.14
Smoker2 (4)4 (9)0.36
DM22 (4)00.16
Osteoporosis9 (18)10 (22)0.96
ASA class0.86
 I3 (6)2 (4)
 II40 (82)37 (80)
 III6 (12)7 (15)
 IV00

ASA = American Society of Anesthesiologists; DM2 = diabetes mellitus type 2; FU = follow-up.

Values are given as number of patients (%) or mean ± SD unless otherwise indicated.

TABLE 2.

Radiographic data for 95 patients

NPT Group (n = 49)FT2 Group (n = 46)p Value
C7 SVA, cm
 Preop6.4 ± 6.99.8 ± 7.10.02
 6 wks postop2.4 ± 3.73.5 ± 4.50.21
 Latest FU4.0 ± 4.25.4 ± 4.50.013
PT, °
 Preop28.7 ± 6.937.5 ± 10.3<0.001
 6 wks postop19.8 ± 533.7 ± 7.6<0.001
 Latest FU24.6 ± 6.635.3 ± 8.9<0.001
LL, °
 Preop−49.6 ± 19.1−31.7 ± 22.9<0.001
6 wks postop−66.1 ± 8.2−46.5 ± 15.2<0.001
 Latest FU−61.7 ± 10.3−2.5 ± 15.3<0.001
PI-LL, °
 Preop19.6 ± 19.240.9 ± 23.7<0.001
 Immediately postop2.7 ± 8.725.9 ± 16.0<0.001
 Latest FU7.2 ± 10.730.3 ± 16.6<0.001
PJA, °
 Preop1.1 ± 10.60.6 ± 9.40.84
 6 wks postop11.0 ± 5.77.4 ± 7.70.03
 Latest FU15.6 ± 8.612.3 ± 13.90.23
TK, °
 Preop36.5 ± 19.718.5 ± 18.0<0.001
6 wks postop40.4 ± 8.219.6 ± 9.8<0.001
 Latest FU42.2 ± 11.023.5 ± 11.4<0.001
CSVL, cm
 Preop2.6 ± 2.73.5 ± 2.50.09
 6 wks postop2.2 ± 1.32.5 ± 2.10.42
 Latest FU2.4 ± 1.62.7 ± 1.60.50

CSVL = central sacral vertical line.

Values are given as mean ± SD unless otherwise indicated.

FIG. 1.
FIG. 1.

Representative case illustration of a patient with postoperative high PT with good alignment (Roussouly FT2). A: Baseline radiographs obtained in a 69-year-old woman who underwent posterior segmental spinal instrumented fusion from T10 to the pelvis for adult degenerative scoliosis. B: Six-week postoperative standing radiographs show good global sagittal balance in the spine with high PT. C: Two-year postoperative standing radiographs demonstrate no PJK or pseudarthrosis. The preoperative (A), 6-week postoperative (B), and 2-year postoperative (C) PJAs are 2°, 10°, and 9°, respectively.

Operative data are presented in Table 3. The majority of surgeries were revisions (63%), performed via a posterior-only approach (86%) with interbody fusions (65%) using rhBMP-2 (98%). The median number of levels instrumented was 15 (IQR 9–16) and was not different between groups.

TABLE 3.

Operative details for 95 patients

NPT Group (n = 49)FT2 Group (n = 46)p Value
Primary op19 (39)16 (35)0.69
UIV
 Upper thoracic (T1–5)32240.07
 Middle thoracic (T6–9)28
 Lower thoracic (T10–L2)1514
Total no. of rods0.59
 237 (76)35 (76)
 38 (16)5 (11)
 44 (8)6 (13)
Rod material0.36
 CC16 (33)22 (48)
 SS33 (67)24 (52)
Approach0.54
 Posterior only41 (84)41 (89)
Pelvic fixation46 (94)41 (89)0.41
Mean no. of levels fused/instrumented10 ± 49 ± 50.44
3CO
 PSO12 (24)8 (17)0.40
 VCR1 (2)3 (7)0.28
Interbody fusion0.50
 ALIF9 (18)5 (11)
 TLIF25 (51)23 (50)
rhBMP-249 (100)44 (96)0.14
 Interbody34 (69)24 (52)0.09
 Posterior48 (98)44 (96)0.52
 Total dose, mg117 ± 58106 ± 730.42
 Per level, mg13.5 ± 7.514.5 ± 11.30.61
EBL, ml1917 ± 12671651 ± 12060.30
Op time, mins512 ± 1564988 ± 1490.45

ALIF = anterior lumbar interbody fusion; CC = cobalt-chrome; EBL = estimated blood loss; ICBG = iliac crest bone graft; PSO = pedicle subtraction osteotomy; SS = stainless steel; TLIF = transforaminal lumbar interbody fusion; VCR = vertebral column resection; 3CO = three-column osteotomy.

Values are given as number of patients (%) or mean ± SD unless otherwise indicated.

The average PJA between UIV and UIV+2 increased in both groups from preoperatively to 6 weeks postoperatively. The PJA continued to increase through the final follow-up in both groups. The overall rate of radiographic PJK using Glattes’ criteria was 40% (n = 38/95; NPT group 47%, FT2 group 33%; p = 0.10). The rate of revision surgery for PJK was 6.3% (n = 6/95) and was not different between groups. The rate of instrumentation failure was 23% (n = 22/95) and was not different between groups. Overall, the revision rate for pseudarthrosis with instrumentation failure was 11.6% (n = 11/95) (Table 4).

TABLE 4.

PJK and rod failure data for 95 patients

NPT Group (n = 49)FT2 Group (n = 46)p Value
PJK
 Radiographic (Glattes’ criteria)23 (47)15 (33)0.10
 Revision4 (8)2 (4)0.45
Rod failure0.63
 None36 (73)32 (70)
 16 (12)7 (15)
 26 (12)3 (7)
Revision for pseudarthrosis5 (10)6 (13)0.66

Values are given as number of patients (%) unless otherwise indicated.

SRS-22r scores were available for 43% of the NPT group and 98% of the FT2 group. Baseline, 1-year, and 2-year domain and subscore median (IQR) values are found in Table 5. There were no differences at baseline or at 1 year after surgery. The lone difference between the two groups was worse pain in the NPT group at 2 years (NPT group 3.7, FT2 group 3.8; p = 0.03), although the difference falls within the minimum detectable measurement difference.

TABLE 5.

PROMs for 95 patients

NPT Group (n = 21)FT2 Group (n = 45)p Value
Baseline SRS scores
 Pain2.4 (1.7–2.8)2.4 (1.8–3.1)0.78
 Activity2.8 (2.1–3.1)3.0 (2.4–3.4)0.46
 Self-Image2.3 (1.8–3.0)2.3 (1.9–3.0)0.88
 Mental Health3.2 (2.4–4.0)3.8 (3.0–4.2)0.22
 Subscore2.7 (2.1–3.3)2.9 (3.3–3.2)0.39
1-yr SRS scores
 Pain4.2 (2.8–4.2)3.7 (3.2–4.2)0.29
 Activity3.4 (3.0–3.9)3.6 (2.8–3.9)0.93
 Self-Image3.5 (2.7–3.9)3.7 (3.3–4.2)0.78
 Mental Health4.1 (3.0–4.5)4.2 (3.8–4.5)0.70
 Subscore3.7 (3.2–4.3)4.5 (4.0–5.0)0.87
2-yr SRS scores
 Pain3.7 (2.6–4.2)3.8 (3.0–4.5)0.03
 Activity3.4 (2.4–4.0)3.7 (3.2–4.0)0.13
 Self-Image3.4 (2.2–4.1)3.7 (3.2–4.0)0.31
 Mental Health3.9 (3.3–5.0)4.2 (3.6–4.6)0.54
 Subscore3.5 (2.6–4.1)3.8 (3.4–4.2)0.18

Values are given as median (IQR).

Discussion

ASD surgery can be associated with mechanical complication rates exceeding 50%.24 Restoration of a normal sagittal alignment is proposed as a critical goal to minimize these complications, particularly for pseudarthrosis with implant failure and PJK.1,57,10 There are wide variations on what is considered normal alignment.8,11,12 The GAP score has proposed alignment goals to decrease the occurrence of mechanical complications.1 This study aimed to investigate the durability of ASD surgeries fixed with persistent lumbopelvic parameter mismatch and high PT in patients with high PI (Roussouly FT2). We found that patients with high PI fixed with persistent lumbopelvic parameter mismatch and high PT had rates of Glattes’ PJK (40%) and bilateral rod fracture (9%) consistent with historical norms and not different from patients fixed to normal sagittal alignment.3,5,1319 Subsequent revision surgery rates for PJK (6.3%) and pseudarthrosis (11.6%) were also comparable with previous studies.3,5,13,1618,20

The rate of radiographic PJK (40%) in our cohort was consistent with previous reports (range 6%–61.7%), although our use of Glattes’ criteria identifies many PJKs of little clinical relevance.9,1316 Importantly, the rate of revision surgery (6.3%) for PJK was not substantially different from previous reports (range 2.3%–17%).13,16,17,20 Factors contributing to PJK after ASD are multifactorial. Prior studies have identified age, BMI, low bone mineral density, proximal anchor type, amount of sagittal plane correction, and global sagittal malalignment as risk factors for PJK.13,14,2124 Undercorrection with good global alignment maintained by pelvic compensation (high PT) may be an attractive surgical plan in some patients, as it may help avoid some factors associated with PJK, such as large changes in LL. Furthermore, the surgical morbidity required of some large sagittal plane corrections, such as three-column osteotomies, may not be appropriate for some patients. In these situations, the potential benefits of an FT2 profile may outweigh the risks associated with large sagittal plane correction surgeries. In our cohort, there were no patients with severe, immediate postoperative forward sagittal malalignment (SVA > 10 cm). This may explain the similarity between rates of PJK and revisions for PJK between our cohort and previous reports.

Our instrumentation failure rate of 23% is consistent with prior studies (range 9%–31.7%), although only 11.6% underwent revision surgery.3,5,18,19 It is important to note that the historical nonunion rate at our institution using rhBMP-2 in operations for ASD is 6.4%, and the majority of patients in this cohort were revision surgeries.25 That the FT2 patients may sustain more frequent pseudarthroses supports the hypothesis that lumbopelvic harmony is an important biomechanical consideration for a successful surgery. One must weigh the risks and benefits of the surgery proposed, however, given the generally more invasive and morbid nature of surgeries producing large changes in LL. Interestingly, the revision rate for pseudarthrosis (11.6%) in our cohort was similar to previous reports and substantially lower than the rate of implant failure.3,5,18 Longer follow-up may reveal a higher rate of reoperation, as pseudarthrosis is associated with poor outcomes over time.26

One cannot conclude that the absence of mechanical failure means that the surgery was a success, however. Data do suggest that restoration of the appropriate Roussouly profile is associated with better PROMs.27 While we are missing PROM responses from the NPT cohort, our data suggest that the FT2 cohort is no worse than the NPT cohort; i.e., it does not have worse 2-year postoperative PROMs. SRS-22r Pain, Activity, and Self-Image scores are substantially better at 1 and 2 years after surgery in the FT2 group. The changes between groups were not different.

There are limitations to this study. It is a retrospective single-center analysis that offers opportunities for selection bias, recall bias, and performance bias. Although not the objective of the study, the potential impact on HRQOL measures related to this specific type of postoperative spinal alignment is imperfectly assessed, as we have substantial missing data from the NPT cohort. Further work to determine the relationship between the FT2 profile and HRQOL is needed, as it is possible that these patients do well or do poorly in the setting of no PJK and a successful fusion, as our conclusions are different from prior studies.27 The use of Glattes’ criteria to define PJK overestimates the rate of clinically relevant PJK. The difference in rates of PJK and revision for PJK is large, supporting this hypothesis. However, one must consider that patients may have been indicated for revision surgery but no surgery was performed, thus causing the mechanical complications requiring revision to be underestimated. Unilateral rod fractures in this series rarely went on to become bilateral fractures, although loss to follow-up may affect this conclusion. While the rates of implant failure and revision for pseudarthrosis approximate historical ASD estimates, we must note that all patients in this cohort received rhBMP-2 at the time of surgery and we may be observing a higher than expected rate of failure. We do not know the surgical decision-making that led to these two distinct alignment profiles, although these surgeries were performed at a time when spinal alignment was often judged by plumb lines and not distribution and magnitude of sagittal curvatures. Finally, no prophylactic techniques were used for PJK prevention, aside from a goal of a balanced postoperative sagittal plane. These techniques may reduce PJK in the near and long term and affect the conclusions of this study.28,29

Conclusions

In this single-center experience, well-balanced patients with high PI fixed with persistent lumbopelvic parameter mismatch and high PT (Roussouly FT2) had rates of PJK and instrumentation failure consistent with historical norms for well-aligned patients and not different from a cohort of well-aligned patients from the same time span. High postoperative PT may be durable in some cases of ASD surgery, and the risks and benefits of individual surgical plans should be discussed and considered with the patient. Further investigations into patients with high postoperative PT are needed to delineate the effect of persistent lumbopelvic malalignment and the risks associated with this postoperative condition.

Disclosures

Dr. Gupta reported royalties from Innomed; royalties from and being a consultant for DePuy and Globus; being a consultant for and fees for travel from Medtronic; nonfinancial support for travel from Globus, Medtronic, DePuy, and Zimmer; being on the Board of Directors of and nonfinancial support for travel from the Scoliosis Research Society; and stock ownership in Johnson & Johnson, outside the submitted work. Dr. Theologis reported personal fees from DePuy Spine, Alphatec, Icotec, Carbofix, Restor3D, Surgalign, and Stryker/K2M, outside the submitted work. Dr. Lenke reported a grant (money to institution) from AO Spine; and being a consultant for Medtronic, Abryx, Acuity Surgical, and EOS Technology, outside the submitted work. Dr. Kelly reported being a Deputy Editor for Wolters Kluwer; being on the Board of Directors of the Scoliosis Research Society; and being on the Steering Committee of AO Spine, outside the submitted work. Dr. Bridwell reported a grant from the Scoliosis Research Society, administered by the International Spine Study Group Foundation, outside the submitted work.

Author Contributions

Conception and design: Kelly, Lertudomphonwanit, Theologis, Bridwell. Acquisition of data: Kelly, Lertudomphonwanit, Gupta, Theologis, Jauregui, Bridwell. Analysis and interpretation of data: Kelly, Lertudomphonwanit, Theologis, Jauregui, Bridwell, Wondra. Drafting the article: Kelly, Lertudomphonwanit, Theologis, Jauregui, Lenke, Bridwell, Wondra. Critically revising the article: Kelly, Gupta, Theologis, Lenke, Bridwell. Reviewed submitted version of manuscript: all authors. Approved the final version of the manuscript on behalf of all authors: Kelly. Statistical analysis: Kelly, Theologis. Administrative/technical/material support: Jauregui. Study supervision: Gupta.

References

  • 1

    Yilgor C, Sogunmez N, Boissiere L, et al. Global Alignment and Proportion (GAP) score: development and validation of a new method of analyzing spinopelvic alignment to predict mechanical complications after adult spinal deformity surgery. J Bone Joint Surg Am. 2017;99(19):16611672.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 2

    Soroceanu A, Diebo BG, Burton D, et al. Radiographical and implant-related complications in adult spinal deformity surgery: incidence, patient risk factors, and impact on health-related quality of life. Spine (Phila Pa 1976). 2015;40(18):14141421.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 3

    Smith JS, Shaffrey CI, Klineberg E, et al. Complication rates associated with 3-column osteotomy in 82 adult spinal deformity patients: retrospective review of a prospectively collected multicenter consecutive series with 2-year follow-up. J Neurosurg Spine. 2017;27(4):444457.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 4

    Riouallon G, Bouyer B, Wolff S. Risk of revision surgery for adult idiopathic scoliosis: a survival analysis of 517 cases over 25 years. Eur Spine J. 2016;25(8):25272534.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 5

    Lertudomphonwanit T, Kelly MP, Bridwell KH, et al. Rod fracture in adult spinal deformity surgery fused to the sacrum: prevalence, risk factors, and impact on health-related quality of life in 526 patients. Spine J. 2018;18(9):16121624.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 6

    Yagi M, Rahm M, Gaines R, et al. Characterization and surgical outcomes of proximal junctional failure in surgically treated patients with adult spinal deformity. Spine (Phila Pa 1976). 2014;39(10):E607E614.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 7

    Cho KJ, Suk SI, Park SR, et al. Risk factors of sagittal decompensation after long posterior instrumentation and fusion for degenerative lumbar scoliosis. Spine (Phila Pa 1976). 2010;35(17):15951601.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 8

    Roussouly P, Gollogly S, Berthonnaud E, Dimnet J. Classification of the normal variation in the sagittal alignment of the human lumbar spine and pelvis in the standing position. Spine (Phila Pa 1976). 2005;30(3):346353.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 9

    Glattes RC, Bridwell KH, Lenke LG, Kim YJ, Rinella A, Edwards C II. Proximal junctional kyphosis in adult spinal deformity following long instrumented posterior spinal fusion: incidence, outcomes, and risk factor analysis. Spine (Phila Pa 1976). 2005;30(14):16431649.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 10

    Sebaaly A, Riouallon G, Obeid I, et al. Proximal junctional kyphosis in adult scoliosis: comparison of four radiological predictor models. Eur Spine J. 2018;27(3):613621.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 11

    Laouissat F, Sebaaly A, Gehrchen M, Roussouly P. Classification of normal sagittal spine alignment: refounding the Roussouly classification. Eur Spine J. 2018;27(8):20022011.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 12

    Bao H, Lafage R, Liabaud B, et al. Three types of sagittal alignment regarding compensation in asymptomatic adults: the contribution of the spine and lower limbs. Eur Spine J. 2018;27(2):397405.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 13

    Hostin R, McCarthy I, O'Brien M, et al. Incidence, mode, and location of acute proximal junctional failures after surgical treatment of adult spinal deformity. Spine (Phila Pa 1976). 2013;38(12):10081015.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 14

    Kim HJ, Bridwell KH, Lenke LG, et al. Proximal junctional kyphosis results in inferior SRS pain subscores in adult deformity patients. Spine (Phila Pa 1976). 2013;38(11):896901.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 15

    Lee JH, Kim JU, Jang JS, Lee SH. Analysis of the incidence and risk factors for the progression of proximal junctional kyphosis following surgical treatment for lumbar degenerative kyphosis: minimum 2-year follow-up. Br J Neurosurg. 2014;28(2):252258.

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    • Search Google Scholar
    • Export Citation
  • 16

    Park SJ, Lee CS, Chung SS, Lee JY, Kang SS, Park SH. Different risk factors of proximal junctional kyphosis and proximal junctional failure following long instrumented fusion to the sacrum for adult spinal deformity: survivorship analysis of 160 patients. Neurosurgery. 2017;80(2):279286.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 17

    Sebaaly A, Sylvestre C, El Quehtani Y, et al. Incidence and risk factors for proximal junctional kyphosis: results of a multicentric study of adult scoliosis. Clin Spine Surg. 2018;31(3):E178E183.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 18

    Smith JS, Shaffrey E, Klineberg E, et al. Prospective multicenter assessment of risk factors for rod fracture following surgery for adult spinal deformity. J Neurosurg Spine. 2014;21(6):9941003.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 19

    Kim YJ, Bridwell KH, Lenke LG, Cho KJ, Edwards CC II, Rinella AS. Pseudarthrosis in adult spinal deformity following multisegmental instrumentation and arthrodesis. J Bone Joint Surg Am. 2006;88(4):721728.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 20

    Annis P, Lawrence BD, Spiker WR, et al. Predictive factors for acute proximal junctional failure after adult deformity surgery with upper instrumented vertebrae in the thoracolumbar spine. Evid Based Spine Care J. 2014;5(2):160162.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 21

    Bridwell KH, Lenke LG, Cho SK, et al. Proximal junctional kyphosis in primary adult deformity surgery: evaluation of 20 degrees as a critical angle. Neurosurgery. 2013;72(6):899906.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 22

    Yagi M, King AB, Boachie-Adjei O. Incidence, risk factors, and natural course of proximal junctional kyphosis: surgical outcomes review of adult idiopathic scoliosis. Minimum 5 years of follow-up. Spine (Phila Pa 1976). 2012;37(17):14791489.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 23

    Nicholls FH, Bae J, Theologis AA, et al. Factors associated with the development of and revision for proximal junctional kyphosis in 440 consecutive adult spinal deformity patients. Spine (Phila Pa 1976). 2017;42(22):16931698.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 24

    Liu FY, Wang T, Yang SD, Wang H, Yang DL, Ding WY. Incidence and risk factors for proximal junctional kyphosis: a meta-analysis. Eur Spine J. 2016;25(8):23762383.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 25

    Kim HJ, Buchowski JM, Zebala LP, Dickson DD, Koester L, Bridwell KH. RhBMP-2 is superior to iliac crest bone graft for long fusions to the sacrum in adult spinal deformity: 4- to 14-year follow-up. Spine (Phila Pa 1976). 2013;38(14):12091215.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 26

    Kornblum MB, Fischgrund JS, Herkowitz HN, Abraham DA, Berkower DL, Ditkoff JS. Degenerative lumbar spondylolisthesis with spinal stenosis: a prospective long-term study comparing fusion and pseudarthrosis. Spine (Phila Pa 1976). 2004;29(7):726734.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 27

    Passias PG, Pierce KE, Raman T, et al. Does matching Roussouly spinal shape and improvement in SRS-Schwab modifier contribute to improved patient-reported outcomes?. Spine (Phila Pa 1976). 2021;46(18):12581263.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 28

    Buell TJ, Bess S, Xu M, et al. Optimal tether configurations and preload tensioning to prevent proximal junctional kyphosis: a finite element analysis. J Neurosurg Spine. 2019;30(5):574584.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 29

    Martin CT, Skolasky RL, Mohamed AS, Kebaish KM. Preliminary results of the effect of prophylactic vertebroplasty on the incidence of proximal junctional complications after posterior spinal fusion to the low thoracic spine. Spine Deform. 2013;1(2):132138.

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    • Search Google Scholar
    • Export Citation
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Figure from Yu et al. (pp 238–246).
  • FIG. 1.

    Representative case illustration of a patient with postoperative high PT with good alignment (Roussouly FT2). A: Baseline radiographs obtained in a 69-year-old woman who underwent posterior segmental spinal instrumented fusion from T10 to the pelvis for adult degenerative scoliosis. B: Six-week postoperative standing radiographs show good global sagittal balance in the spine with high PT. C: Two-year postoperative standing radiographs demonstrate no PJK or pseudarthrosis. The preoperative (A), 6-week postoperative (B), and 2-year postoperative (C) PJAs are 2°, 10°, and 9°, respectively.

  • 1

    Yilgor C, Sogunmez N, Boissiere L, et al. Global Alignment and Proportion (GAP) score: development and validation of a new method of analyzing spinopelvic alignment to predict mechanical complications after adult spinal deformity surgery. J Bone Joint Surg Am. 2017;99(19):16611672.

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    • Search Google Scholar
    • Export Citation
  • 2

    Soroceanu A, Diebo BG, Burton D, et al. Radiographical and implant-related complications in adult spinal deformity surgery: incidence, patient risk factors, and impact on health-related quality of life. Spine (Phila Pa 1976). 2015;40(18):14141421.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 3

    Smith JS, Shaffrey CI, Klineberg E, et al. Complication rates associated with 3-column osteotomy in 82 adult spinal deformity patients: retrospective review of a prospectively collected multicenter consecutive series with 2-year follow-up. J Neurosurg Spine. 2017;27(4):444457.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 4

    Riouallon G, Bouyer B, Wolff S. Risk of revision surgery for adult idiopathic scoliosis: a survival analysis of 517 cases over 25 years. Eur Spine J. 2016;25(8):25272534.

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    • Search Google Scholar
    • Export Citation
  • 5

    Lertudomphonwanit T, Kelly MP, Bridwell KH, et al. Rod fracture in adult spinal deformity surgery fused to the sacrum: prevalence, risk factors, and impact on health-related quality of life in 526 patients. Spine J. 2018;18(9):16121624.

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    • Search Google Scholar
    • Export Citation
  • 6

    Yagi M, Rahm M, Gaines R, et al. Characterization and surgical outcomes of proximal junctional failure in surgically treated patients with adult spinal deformity. Spine (Phila Pa 1976). 2014;39(10):E607E614.

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    • Search Google Scholar
    • Export Citation
  • 7

    Cho KJ, Suk SI, Park SR, et al. Risk factors of sagittal decompensation after long posterior instrumentation and fusion for degenerative lumbar scoliosis. Spine (Phila Pa 1976). 2010;35(17):15951601.

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    • Search Google Scholar
    • Export Citation
  • 8

    Roussouly P, Gollogly S, Berthonnaud E, Dimnet J. Classification of the normal variation in the sagittal alignment of the human lumbar spine and pelvis in the standing position. Spine (Phila Pa 1976). 2005;30(3):346353.

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    • Search Google Scholar
    • Export Citation
  • 9

    Glattes RC, Bridwell KH, Lenke LG, Kim YJ, Rinella A, Edwards C II. Proximal junctional kyphosis in adult spinal deformity following long instrumented posterior spinal fusion: incidence, outcomes, and risk factor analysis. Spine (Phila Pa 1976). 2005;30(14):16431649.

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    • Search Google Scholar
    • Export Citation
  • 10

    Sebaaly A, Riouallon G, Obeid I, et al. Proximal junctional kyphosis in adult scoliosis: comparison of four radiological predictor models. Eur Spine J. 2018;27(3):613621.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 11

    Laouissat F, Sebaaly A, Gehrchen M, Roussouly P. Classification of normal sagittal spine alignment: refounding the Roussouly classification. Eur Spine J. 2018;27(8):20022011.

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    • Search Google Scholar
    • Export Citation
  • 12

    Bao H, Lafage R, Liabaud B, et al. Three types of sagittal alignment regarding compensation in asymptomatic adults: the contribution of the spine and lower limbs. Eur Spine J. 2018;27(2):397405.

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    • Search Google Scholar
    • Export Citation
  • 13

    Hostin R, McCarthy I, O'Brien M, et al. Incidence, mode, and location of acute proximal junctional failures after surgical treatment of adult spinal deformity. Spine (Phila Pa 1976). 2013;38(12):10081015.

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    • Export Citation
  • 14

    Kim HJ, Bridwell KH, Lenke LG, et al. Proximal junctional kyphosis results in inferior SRS pain subscores in adult deformity patients. Spine (Phila Pa 1976). 2013;38(11):896901.

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    • Search Google Scholar
    • Export Citation
  • 15

    Lee JH, Kim JU, Jang JS, Lee SH. Analysis of the incidence and risk factors for the progression of proximal junctional kyphosis following surgical treatment for lumbar degenerative kyphosis: minimum 2-year follow-up. Br J Neurosurg. 2014;28(2):252258.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 16

    Park SJ, Lee CS, Chung SS, Lee JY, Kang SS, Park SH. Different risk factors of proximal junctional kyphosis and proximal junctional failure following long instrumented fusion to the sacrum for adult spinal deformity: survivorship analysis of 160 patients. Neurosurgery. 2017;80(2):279286.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 17

    Sebaaly A, Sylvestre C, El Quehtani Y, et al. Incidence and risk factors for proximal junctional kyphosis: results of a multicentric study of adult scoliosis. Clin Spine Surg. 2018;31(3):E178E183.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 18

    Smith JS, Shaffrey E, Klineberg E, et al. Prospective multicenter assessment of risk factors for rod fracture following surgery for adult spinal deformity. J Neurosurg Spine. 2014;21(6):9941003.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 19

    Kim YJ, Bridwell KH, Lenke LG, Cho KJ, Edwards CC II, Rinella AS. Pseudarthrosis in adult spinal deformity following multisegmental instrumentation and arthrodesis. J Bone Joint Surg Am. 2006;88(4):721728.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 20

    Annis P, Lawrence BD, Spiker WR, et al. Predictive factors for acute proximal junctional failure after adult deformity surgery with upper instrumented vertebrae in the thoracolumbar spine. Evid Based Spine Care J. 2014;5(2):160162.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 21

    Bridwell KH, Lenke LG, Cho SK, et al. Proximal junctional kyphosis in primary adult deformity surgery: evaluation of 20 degrees as a critical angle. Neurosurgery. 2013;72(6):899906.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 22

    Yagi M, King AB, Boachie-Adjei O. Incidence, risk factors, and natural course of proximal junctional kyphosis: surgical outcomes review of adult idiopathic scoliosis. Minimum 5 years of follow-up. Spine (Phila Pa 1976). 2012;37(17):14791489.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 23

    Nicholls FH, Bae J, Theologis AA, et al. Factors associated with the development of and revision for proximal junctional kyphosis in 440 consecutive adult spinal deformity patients. Spine (Phila Pa 1976). 2017;42(22):16931698.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 24

    Liu FY, Wang T, Yang SD, Wang H, Yang DL, Ding WY. Incidence and risk factors for proximal junctional kyphosis: a meta-analysis. Eur Spine J. 2016;25(8):23762383.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 25

    Kim HJ, Buchowski JM, Zebala LP, Dickson DD, Koester L, Bridwell KH. RhBMP-2 is superior to iliac crest bone graft for long fusions to the sacrum in adult spinal deformity: 4- to 14-year follow-up. Spine (Phila Pa 1976). 2013;38(14):12091215.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 26

    Kornblum MB, Fischgrund JS, Herkowitz HN, Abraham DA, Berkower DL, Ditkoff JS. Degenerative lumbar spondylolisthesis with spinal stenosis: a prospective long-term study comparing fusion and pseudarthrosis. Spine (Phila Pa 1976). 2004;29(7):726734.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 27

    Passias PG, Pierce KE, Raman T, et al. Does matching Roussouly spinal shape and improvement in SRS-Schwab modifier contribute to improved patient-reported outcomes?. Spine (Phila Pa 1976). 2021;46(18):12581263.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 28

    Buell TJ, Bess S, Xu M, et al. Optimal tether configurations and preload tensioning to prevent proximal junctional kyphosis: a finite element analysis. J Neurosurg Spine. 2019;30(5):574584.

    • PubMed
    • Search Google Scholar
    • Export Citation
  • 29

    Martin CT, Skolasky RL, Mohamed AS, Kebaish KM. Preliminary results of the effect of prophylactic vertebroplasty on the incidence of proximal junctional complications after posterior spinal fusion to the low thoracic spine. Spine Deform. 2013;1(2):132138.

    • PubMed
    • Search Google Scholar
    • Export Citation

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