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Proximal junctional kyphosis in pediatric spinal deformity surgery: a systematic review and critical analysis

Abstract

Purpose

Proximal junctional kyphosis (PJK) is a commonly encountered clinical and radiographic phenomenon after pediatric and adolescent spinal deformity surgery that may lead to post-operative deformity, pain, and dissatisfaction. Understanding the risk factors of PJK can be useful for pre-operative informed consent as well as to identify any potential preventative strategies.

Methods

We performed a systematic review and critical analysis following the PRISMA statement in July 2019 by searching the PubMed, Scopus, and Embase databases, including all prior published studies. We included articles with data on PJK in patients with operative pediatric and adolescent scoliosis and those that detailed risk factors and/or preventative strategies for PJK. Levels of evidence were determined based on consensus. Findings were summarized and grades of recommendation were assigned by consensus. This study was registered in the PROSPERO database; 202,457.

Results

Six hundred and thirty five studies were identified. Thirty-seven studies met criteria for inclusion into the analysis. No studies including neuromuscular scoliosis met inclusion criteria. No findings had Grade A evidence. There were 4 findings found to contribute to PJK with Grade B evidence in EOS: higher number of distractions, disruption of posterior elements, greater sagittal plane correction. There was no difference in incidence noted between etiology of the curvature. Five findings with Grade B evidence were found to contribute to PJK in AIS populations: higher pre-operative thoracic kyphosis, higher pre-operative lumbar lordosis, longer fusion constructs, greater sagittal plane correction, and posterior versus anterior fusion constructs.

Conclusion

Greater sagittal plane correction has Grade B evidence as a risk factor for PJK in both EOS and AIS populations. In EOS patients, an increased number of distractions and posterior element disruption are Grade B risk factors. In AIS patients, longer fusion constructs, higher pre-operative thoracic kyphosis and lumbar lordosis, and posterior (as opposed to anterior) constructs also contributed to PJK with Grade B evidence. These findings can guide informed consent and surgical management, and provide the foundation for future studies.

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References

  1. 1.

    Reames DL, Kasliwal MK, Smith JS et al (2015) Time to development, clinical and radiographic characteristics, and management of proximal junctional kyphosis following adult thoracolumbar instrumented fusion for spinal deformity. J Spinal Disord Tech 28:106–114

    Article  Google Scholar 

  2. 2.

    Lee GA, Betz RR, Clements DH 3rd et al (1999) Proximal kyphosis after posterior spinal fusion in patients with idiopathic scoliosis. Spine (Phila Pa 1976) 24:795–799

    CAS  Article  Google Scholar 

  3. 3.

    Glattes RC, Bridwell KH, Lenke LG et al (2005) Proximal junctional kyphosis in adult spinal deformity following long instrumented posterior spinal fusion. Incidence, outcomes, and risk factor analysis. Spine 30:1643–1649

    PubMed  Article  PubMed Central  Google Scholar 

  4. 4.

    Helgeson MD, Shah SA, Newton PO et al (2010) Evaluation of proximal junctional kyphosis in adolescent idiopathic scoliosis following pedicle screw, hook, or hybrid instrumentation. Spine (Phila Pa 1976) 35:177–181

    Article  Google Scholar 

  5. 5.

    Joukhadar N, Kubat O, Heflin J et al (2019) Superior extension of upper instrumented vertebrae in distraction-based surgery: a surrogate for clinically significant proximal junctional kyphosis. Spine Deform 7:371–375

    PubMed  Article  Google Scholar 

  6. 6.

    Chen X, Xu L, Qiu Y et al (2018) Incidence, risk factors, and evolution of proximal junctional kyphosis after posterior hemivertebra resection and short fusion in young children with congenital scoliosis. Spine 43:1293–1300

    Google Scholar 

  7. 7.

    Balioglu MB, Atici Y, Albayrak A et al (2016) The effect of distraction-based growth-friendly spinal instrumentation on growth in early-onset scoliosis. Acta Orthop Belg 82:715–722

    CAS  PubMed  Google Scholar 

  8. 8.

    Chen Z, Li S, Qiu Y et al (2017) Evolution of the postoperative sagittal spinal profile in early-onset scoliosis: is there a difference between rib-based and spine-based growth-friendly instrumentation? J Neurosurg Pediatr 6:513–606

    Google Scholar 

  9. 9.

    Chen X, Chen ZH, Qiu Y et al (2017) Proximal junctional kyphosis after posterior spinal instrumentation and fusion in young children with congenital scoliosis: a preliminary report on its incidence and risk factors. Spine (Phila Pa 1976) 20:1197–1203

    Article  Google Scholar 

  10. 10.

    Chen Z, Qiu Y, Zhu Z et al (2017) How does hyperkyphotic early-onset scoliosis respond to growing rod treatment? J Pediatr Orthop 37:e593–e598

    PubMed  Article  PubMed Central  Google Scholar 

  11. 11.

    Inaparthy P, Queruz JC, Bhagawati D et al (2016) Incidence of proximal junctional kyphosis with magnetic expansion control rods in early onset scoliosis. Eur Spine J 25:3308–3315

    CAS  PubMed  Article  PubMed Central  Google Scholar 

  12. 12.

    Carender CN, Morris WZ, Poe-Kochert C et al (2016) Low pelvic incidence is associated with proximal junctional kyphosis in patients treated with growing rods. Spine 9:792–797

    Article  Google Scholar 

  13. 13.

    El-Hawary R, Sturm P, Cahill P et al (2017) What is the risk of developing proximal junctional kyphosis during growth friendly treatments for early-onset scoliosis? J Pediatr Orthop 37:86–91

    PubMed  Article  PubMed Central  Google Scholar 

  14. 14.

    Watanabe K, Uno K, Suzuki T et al (2016) Risk factors for proximal junctional kyphosis associated with dual-rod growing-rod surgery for early-onset scoliosis. Clin Spine Surg 29:428–433

    Article  Google Scholar 

  15. 15.

    Shah SA, Karatas AF, Dhawale AA et al (2014) The effect of serial growing rod lengthening on the sagittal profile and pelvic parameters in early-onset scoliosis. Spine (Phila Pa 1976) 39:1311–1317

    Article  Google Scholar 

  16. 16.

    Li Y, Gold M, Karlin L (2013) Proximal junctional kyphosis after vertical expandable prosthetic titanium rib insertion. Spine Deform 1(6):425–433

    PubMed  Article  PubMed Central  Google Scholar 

  17. 17.

    Wang Y, Kawakami N, Tsuji T et al (2017) Proximal junctional kyphosis following posterior hemivertebra resection and short fusion in children younger than 10 years. Clin Spine Surg 4:37–76

    Google Scholar 

  18. 18.

    Lampe LP, Bovingloh AS, Gosheger G et al (2019) Magnetically controlled growing rods in treatment of early-onset scoliosis. Spine 44:1201–1210

    PubMed  Article  PubMed Central  Google Scholar 

  19. 19.

    Pan A, Hai Y, Yang J et al (2018) Upper instrumented vertebrae distal to T2 leads to a higher incidence of proximal junctional kyphosis during growing-rod treatment for early onset scoliosis. Clin Spine Surg 31:E337–E341

    PubMed  Article  PubMed Central  Google Scholar 

  20. 20.

    Erdogan S, Polat B, Atici Y et al (2019) Comparison of the effects of magnetically controlled growing rod and traditional growing rod techniques on the sagittal plane in the treatment of early-onset scoliosis. J Korean Neurosurg Soc 62(5):577–585

    PubMed  PubMed Central  Article  Google Scholar 

  21. 21.

    Alzakri A, Vergari C, Van den Abbeele M et al (2019) global sagittal alignment and proximal junctional kyphosis in adolescent idiopathic scoliosis. Spine Deform 7:236–244

    PubMed  Article  Google Scholar 

  22. 22.

    Ohrt-Nissen S, Bari T, Dahl B et al (2018) Sagittal alignment after surgical treatment of adolescent idiopathic scoliosis-application of the roussouly classification. Spine Deform 6:537–544

    PubMed  Article  Google Scholar 

  23. 23.

    Li J, Zhao Z, Tseng C et al (2018) selective fusion in lenke 5 adolescent idiopathic scoliosis. World Neurosurg 118:e784–e791

    PubMed  Article  Google Scholar 

  24. 24.

    Zhao J, Yang M, Yang Y et al (2018) Proximal junctional kyphosis following correction surgery in the Lenke 5 adolescent idiopathic scoliosis patient. J Orthop Sci 23:744–749

    PubMed  Article  Google Scholar 

  25. 25.

    Pahys JM, Vivas AC, Samdani AF et al (2018) Assessment of proximal junctional kyphosis and shoulder balance with proximal screws versus hooks in posterior spinal fusion for adolescent idiopathic scoliosis. Spine 43:E1322–E1328

    PubMed  Article  Google Scholar 

  26. 26.

    Lonner BS, Ren Y, Newton PO et al (2017) Risk factors of proximal junctional kyphosis in adolescent idiopathic scoliosis-the pelvis and other considerations. Spine Deformity 3:181–188

    Article  Google Scholar 

  27. 27.

    Angelliaume A, Ferrero E, Mazda K et al (2017) Titanium vs cobalt chromium: what is the best rod material to enhance adolescent idiopathic scoliosis correction with sublaminar bands? Eur Spine J 26:1732–1738

    PubMed  Article  Google Scholar 

  28. 28.

    Dubory A, Miladi L, Ilharreborde B et al (2017) Cobb-1 versus cobb-to-cobb anterior fusion for adolescent idiopathic scoliosis Lenke 5C curves: a radiological comparative study. Eur Spine J 26:1711–1720

    PubMed  Article  Google Scholar 

  29. 29.

    Sun Z, Qiu G, Zhao Y, Guo S et al (2015) Risk factors of proximal junctional angle increase after selective posterior thoracolumbar/lumbar fusion in patients with adolescent idiopathic scoliosis. Eur Spine J 24:290–297

    PubMed  Article  Google Scholar 

  30. 30.

    Liu T, Hai Y (2014) Sagittal plane analysis of selective posterior thoracic spinal fusion in adolescent idiopathic scoliosis: a comparison study of all pedicle screw and hybrid instrumentation. J Spinal Disord Tech 5:277–282

    Article  Google Scholar 

  31. 31.

    Wang J, Zhao Y, Shen B et al (2010) Risk factor analysis of proximal junctional kyphosis after posterior fusion in patients with idiopathic scoliosis. Injury Int J Care Injured 41:415–420

    Article  Google Scholar 

  32. 32.

    Sponseller PD, Betz R, Newton PO et al (2009) Differences in curve behavior after fusion in adolescent idiopathic scoliosis patients with open triradiate cartilages. Spine 8:827–831

    Article  Google Scholar 

  33. 33.

    Hollenbeck SM, Glattes RC, Asher MA et al (2008) The prevalence of increased proximal junctional flexion following posterior instrumentation and arthrodesis for adolescent idiopathic scoliosis. Spine 15:1675–1681

    Article  Google Scholar 

  34. 34.

    Kim YJ, Lenke LG, Bridwell KH et al (2007) Proximal junctional kyphosis in adolescent idiopathic scoliosis after 3 different types of posterior segmental spinal instrumentation and fusions: incidence and risk factor analysis of 410 cases. Spine 24:2731–2738

    Article  Google Scholar 

  35. 35.

    Hee HT, Yu ZR, Wong HK (2007) Comparison of segmental pedicle screw instrumentation versus anterior instrumentation in adolescent idiopathic thoracolumbar and lumbar scoliosis. Spine 14:1533–1542

    Article  Google Scholar 

  36. 36.

    Yang SH, Chen PQ (2003) Proximal kyphosis after short posterior fusion for thoracolumbar scoliosis. Clin Orthop Relat Res 411:152–158

    Article  Google Scholar 

  37. 37.

    Rhee JM, Bridwell KH, Won DS et al (2002) Sagittal plane analysis of adolescent idiopathic scoliosis: the effect of anterior versus posterior instrumentation. Spine 21:2350–2356

    Article  Google Scholar 

  38. 38.

    Ferrero E, Bocahut N, Lefevre Y et al (2018) Proximal junctional kyphosis in thoracic adolescent idiopathic scoliosis: risk factors and compensatory mechanisms in a multicenter national cohort. Eur Spine J 27:2241–2250

    PubMed  Article  PubMed Central  Google Scholar 

  39. 39.

    Homans JF, Kruyt MC, Schlösser TPC et al (2020) Changes in the position of the junctional vertebrae after posterior spinal fusion in adolescent idiopathic scoliosis: implication in risk assessment of proximal junctional kyphosis development. J Pediatr Orthop 40(2):e84–e90

    PubMed  Article  PubMed Central  Google Scholar 

  40. 40.

    Yan C, Li Y, Yu Z (2016) Prevalence and consequences of the proximal junctional kyphosis after spinal deformity surgery: a meta-analysis. Medicine (Baltimore) 95(20):e3471

    Article  Google Scholar 

  41. 41.

    Akbarnia BA, Emans JB (2010) Complications of growth-sparing surgery in early onset scoliosis. Spine 35:2193–2204

    PubMed  Article  Google Scholar 

  42. 42.

    Cahill PJ, Wang W, Asghar J et al (2012) The use of a transition rod may prevent proximal junctional kyphosis in the thoracic spine after scoliosis surgery: a finite element analysis. Spine (Phila Pa 1976) 37(12):E687-95

    Article  Google Scholar 

  43. 43.

    Cammarata M, Aubin CÉ, Wang X et al (2014) Biomechanical risk factors for proximal junctional kyphosis: a detailed numerical analysis of surgical instrumentation variables. Spine (Phila Pa 1976) 39(8):E500-7

    Article  Google Scholar 

  44. 44.

    Pasha S, Baldwin K (2019) Surgical outcome differences between the 3D subtypes of right thoracic adolescent idiopathic scoliosis. Eur Spine J 28(12):3076–3084

    PubMed  Article  Google Scholar 

  45. 45.

    Pasha S, Hassanzadeh P, Ecker M et al (2019) A hierarchical classification of adolescent idiopathic scoliosis: identifying the distinguishing features in 3D spinal deformities. PLoS One 14:e0213406

    CAS  PubMed  PubMed Central  Article  Google Scholar 

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Acknowledgements

SP thanks the National Institute of Health for support (R21AR075971-02).

Funding

No funds, grants, or other support was received.

Author information

Affiliations

Authors

Contributions

ME study design, data collection, statistical analysis, manuscript draft and final approval. KDB study design, statistical analysis, manuscript review, final approval. SP manuscript draft, final approval. RJM study design, data collection, statistical analysis, manuscript draft, manuscript review and final approval

Corresponding author

Correspondence to R. Justin Mistovich.

Ethics declarations

Conflict of interest

R. Justin Mistovich serves as a paid consultant to OrthoPediatrics and Philips Healthcare Companies. Keith D. Baldwin owns stock in Pfizer. Mehmet Erkilinc and Saba Pasha have no financial interest.

Ethical approval

Systematic review. No patient information was accessed for this manuscript. IRB exempt.

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Appendices

Appendix 1

EOS findings with inconclusive evidence

Coronal plane curve magnitude

Rationale: two Level 3 manuscript reported > 40° of proximal thoracic scoliosis as a risk factor [14, 19]. One Level 3 paper found coronal curve magnitude did not affect rates of PJK [5].

Pre-operative cervical lordosis

Rationale: one Level 3 study found that patients who developed PJK had higher pre-operative cervical lordosis [13].

Pelvic incidence

Rationale: one Level 4 study reported a lower PI associated with increased PJK [12] while two Level 3 studies reported increased risk ratio of developing PJK with a higher PI [13, 19].

Malpositioned screw at UIV

Rationale: one Level 3 study reported that 6/7 patients who developed PJK had ≥ 1 malpositioned screw [17].

Longer fusion constructs

Rationale: two Level 3 studies reported a greater number of fused levels in the PJK group when compared to controls [6, 9].

Selection of UIV influences the rate of PJK

Rationale: one level 3 study reported that UIV distal to T2 (hazard ratio = 5.474; P = 0.044) were found to be independent risk factors of PJK in the multivariate analyses [19].

Selection of LIV influences the rate of PJK

Rationale: one Level 3 study described LIV at or cranial to L3 as a risk factor for PJK [14].

Gender

Rationale: one Level 3 study reported higher incidence of PJK in males [11] while a Level 4 study reported a higher incidence in females [12]. One Level 3 study showed no difference [19].

AIS findings with inconclusive evidence

High lordosis/pelvic incidence ratio

Rationale: one Level 2 study reported higher pre-op and post-op lumbar lordosis/PT ratios in patients who developed PJK [26].

Disruption of posterior elements

Rationale: one Level three study reported a greater frequency of disrupted junctional ligaments in the PJK group [24], and another study reported a single case of posterior ligamentous failure in a patient with PJK [27].

Rod material

Rationale: a Level 3 study found no difference in PJK risk between titanium and cobalt chrome rods [30]. Another Level 3 study reported that significantly higher risk with cobalt chromium (28%), compared to titanium and stainless steel (12%) (p < 0.0001) [38].

Bone graft material

Rationale: a single Level 3 study described autologous bone graft as a risk factor for PJK [31].

Use of distraction

Rationale: a single Level 3 study described distraction during deformity correction as a risk factor [31].

Body mass index

Rationale: one Level 2, one Level 3 and one Level 4 study found no significant difference in BMI between PJK and non-PJK cohorts [26, 33, 38]. A level 3 study reported a significantly increased BMI in the PJK group [4].

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Erkilinc, M., Baldwin, K.D., Pasha, S. et al. Proximal junctional kyphosis in pediatric spinal deformity surgery: a systematic review and critical analysis. Spine Deform (2021). https://doi.org/10.1007/s43390-021-00429-w

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Keywords

  • Proximal junctional kyphosis
  • Adolescent idiopathic scoliosis
  • Early-onset scoliosis
  • Pediatric
  • Spine