Proximal junctional kyphosis in thoracic adolescent idiopathic scoliosis: risk factors and compensatory mechanisms in a multicenter national cohort

Ferrero, Emmanuelle; Bocahut, Nicolas; Lefèvre, Yan; Roussouly, Pierre; Pesenti, Sébastien; Lakhal, Walid; Odent, Thierry; Morin, C.; Clément, Jean-Luc; Compagnon, Roxane; Gauzy, Jérôme Sales de; Jouve, Jean-Luc; Mazda, Keyvan; Abelin-Genevois, Kariman; Ilharreborde, Brice; Scoliose, Groupe d’Etude sur la

doi:10.1007/s00586-018-5640-y

Cited by 56 publications

(62 citation statements)

References 17 publications

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“…Although Wang et al reported greater Scoliosis curve correction to be associated with PJK, 49 we and others did not observe this. 54 Patients with PJK had smaller PI and larger PI–LL mismatch after surgery compared to the noPJK group. Yang et al suggested that a smaller PI implied poor capacity for pelvic compensation to sagittal imbalance and proposed that a critical PI for compensation was greater than 39°, 41 which is close to the pre- and post-operative PI seen in PJK patients within our cohort, 37.8° and 39.8°, respectively.…”

Section: Discussionmentioning

confidence: 88%

Sagittal spinopelvic changes after posterior spinal fusion in adolescent idiopathic scoliosis

Burton

Karkenny

Schulz

et al. 2020

Journal of Children's Orthopaedics

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Purpose This article examines if longer posterior spinal fusions with instrumentation (PSFI) into the lumbar spine (L3/4) alter spinopelvic parameters compared with selective fusions to T12/L1/L2 in adolescent idiopathic scoliosis (AIS) patients. Methods We analysed radiographs of 84 AIS patients, 58 (69%) females and 26 (31%) males, who underwent PSFI at an mean age of 15 years ± 2.5 years, range 10 years to 21 years, between 1st January 2007 and 31st December 2014. Radiographic parameters were measured pre- and post-operatively at most recent follow-up (range 2 years to 8.2 years): pelvic incidence (PI), lumbar lordosis (LL, L1–S1 and L4–S1), sagittal vertical alignment (SVA), scoliosis angle and proximal junctional kyphosis (PJK). PI–LL was calculated. Data was analysed using t-tests or Wilcoxon rank-sum tests. Results In total, 32 patients underwent a selective fusion with lowest instrumented vertebra (LIV) T12–L2, and 52 patients underwent a fusion with LIV L3–L4. In both groups, scoliosis angle was significantly corrected at follow-up (p < 0.005). Pre-operatively, both groups had similar LL (L1–S1) and PI–LL. Post-operatively, LL increased in the L3–4 fusion group (p < 0.005) but did not change in the selective fusion group (p = 0.116). This change in LL in the L3–4 fusion group affected the post-operative PI–LL (T12–L2 fusion -4.9° versus L3–4 fusion -13.6°, p = 0.002). No differences were seen in PI, SVA or LL L4–S1 between groups. Radiographic PJK occurred in seven of the L3–4 patients with and without PJK (noPJK –8.8° versus PJK –25.8°, p = 0.026). Conclusions In patients who underwent a fusion ending at L3 or L4, LL was increased. This altered the PI–LL relationship, and appeared to increase the risk of PJK. Level of evidence III

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Section: Discussionmentioning

confidence: 88%

Sagittal spinopelvic changes after posterior spinal fusion in adolescent idiopathic scoliosis

Burton

Karkenny

Schulz

et al. 2020

Journal of Children's Orthopaedics

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“…This was lower than previously reported incidence at 7% to 46%. 3,4,6,[8][9][10]12 This discrepancy may be due to the difference of PJA/PJK definition, which varied among studies. Some studies measure the difference between pre-and postoperative radiographs, while others, similar to this study, measure the difference between the immediate postoperative and latest follow-up film.…”

Section: Discussionmentioning

confidence: 99%

“…Interestingly, in our study, one-hook/one-screw at UIV had no PJK with average 2.2 years follow-up. Ferrero et al 12 analyzed the incidence of PJK in AIS and reported one-hook/one-screw was equivalent to bilateral hooks at UIV in terms of PJK 12 . We speculate that one-hook/one-screw constructs reduced the rate of PJK by allowing us to keep at least one facet capsule away from violation.…”

Section: Discussionmentioning

confidence: 99%

“…PJA was defined as the caudal endplate of the UIV to the cephalad endplate of the UIV+2 vertebrae. 9 PJK was evaluated using lateral whole-spine upright radiographs immediate after surgery and at the final follow-up based on following criteria as previously described 12 : PJA ≥ 10° and PJA progression of ≥10° at the final follow-up. Spinal levels were assigned a number increasing caudally with C0 being 1 and T1 being 8.…”

Section: Methodsmentioning

confidence: 99%

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Incidence of Proximal Junctional Kyphosis With Pedicle Screws at Upper Instrumented Vertebrae in Posterior Spinal Fusion for Adolescent Idiopathic Scoliosis

Ogura

Glassman

Sucato

et al. 2020

Global Spine Journal

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Study Design: Longitudinal cohort. Objectives: Posterior spinal fusion (PSF) using all-pedicle screw constructs has become the standard procedure in the treatment of adolescent idiopathic scoliosis (AIS). However, there have been several reports that all-pedicle screw constructs or the use of pedicle screws at the upper instrumented vertebrae (UIV) increases the incidence of proximal junctional kyphosis (PJK). We aimed to evaluate the impact of instrumentation type on the incidence of PJK following PSF for AIS. Methods: We performed a stratified random sampling from 3654 patients enrolled in a multicenter database of surgically treated AIS to obtain a representative sample from all Lenke types. Patients were then allocated into 3 groups based on the instrumentation type: all-pedicle screw (PS), hook at UIV with pedicle screws distally (HT), and hybrid constructs (HB). We measured proximal junctional angle (PJA) and defined PJK as PJA ≥ 10° and PJA progression of >10° at the final follow-up. Results: Fifteen (4.3%) of 345 cases had PJK. PJK was significantly more common in PS (11%) compared with HB (1%) and HT (0%) ( P < .001). PJK patients were similar to non-PJK patients regarding age, sex, curve type, UIV, and preoperative coronal Cobb angle. Thoracic kyphosis was significantly higher in the PJK group before surgery. Patients who developed PJK had a statistically significantly larger negative sagittal balance compared with the non-PJK group. Conclusion: The incidence of PJK was 4.3% and was more common in all-pedicle screw constructs. Using hooks at UIV might be a treatment strategy to limit PJK.

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“…[21][22][23][24] Furthermore, inadequate restoration of TK at the instrumented segments may lead to a compensatory increase in TK at the noninstrumented upper junction, thus increasing the chance of PJK in such patients. 25,26 Based on our analysis of the asymptomatic volunteers, the ideal relationship between thoracic and lumbar curves was established as TK to be 41% of LL, with a deviation from this relationship indicating either inadequate or excessive kyphotic restoration. Our study showed that patients who had a lack of kyphosis restoration in relation to lordosis correction (defined as DTK < 41% DLL) exhibited a higher rate of PJK in comparison to those who achieved kyphosis restoration in excess (DTK > 41%).…”

Section: Discussionmentioning

confidence: 99%

In the Relationship Between Change in Kyphosis and Change in Lordosis: Which Drives Which?

Ang

Lafage

Elysée

et al. 2020

Global Spine Journal

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Study Design: Retrospective single-center study. Objective: Investigate the effect of posterior instrumentation on the relationship between lordosis and kyphosis. Methods: Surgically treated patients with a minimum of 6 months of follow-up were analyzed. Asymptomatic volunteers served to show the normal anatomical relationship between thoracic and lumbar curves. Patients were stratified based on postoperative instrumentation: “Thoracic Fusion” = complete fusion of thoracic spine; “Lumbar Fusion” = complete fusion of lumbar spine; and “Complete Fusion” = fusion from sacrum to at least T5. Bivariate correlations and regression analysis were used to evaluate the relationship between change in thoracic kyphosis (ΔTK) and change in spinopelvic mismatch (ΔPI-LL; pelvic incidence-lumbar lordosis) before and after fusion. Analyses were repeated in “Lumbar Fusion” patients with flexible preoperative thoracic spines. Results: For asymptomatic volunteers, the natural anatomical relationship between TK and LL was found to be TK = 41% of LL ( r = 0.425, P < .001). A total of 153 of 167 adult spinal deformity patients were included (62 years old, 26.7 kg/m2, 78% female). Mean follow-up was 11.5 ± 6.8 months. “Thoracic Fusion” group showed no alteration in the natural relationship between TK and LL (ΔTK = 39% ΔPI-LL), whereas “Lumbar Fusion” group had a reduction in reciprocal change (ΔTK = 34% ΔPI-LL) although a subanalysis of patients in the “Lumbar Fusion” group with flexible thoracic spines showed a marked compensation in reciprocal change with (ΔTK = 58% ΔPI-LL). Conclusion: The relationship between ΔTK and ΔPI-LL is dependent on level instrumented. “Thoracic Fusion” drives change in LL while this relationship is affected by TK’s natural stiffness in “Lumbar Fusion” patients.

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Proximal junctional kyphosis in thoracic adolescent idiopathic scoliosis: risk factors and compensatory mechanisms in a multicenter national cohort

Cited by 56 publications

References 17 publications

Sagittal spinopelvic changes after posterior spinal fusion in adolescent idiopathic scoliosis

Sagittal spinopelvic changes after posterior spinal fusion in adolescent idiopathic scoliosis

Incidence of Proximal Junctional Kyphosis With Pedicle Screws at Upper Instrumented Vertebrae in Posterior Spinal Fusion for Adolescent Idiopathic Scoliosis

In the Relationship Between Change in Kyphosis and Change in Lordosis: Which Drives Which?

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