Large Difference Between Proximal Junctional Angle and Rod Contouring Angle is a Risk Factor for Proximal Junctional Kyphosis

Wang, Jie; Yang, Ningning; Luo, Ming; Xia, Lei; Li, Ning

doi:10.1016/j.wneu.2020.01.136

Cited by 19 publications

(30 citation statements)

References 20 publications

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“…[2][3][4][5][6] A plethora of literature exists on the clinical and radiographic risk factors for PJK. 3,[7][8][9][10][11][12][13][14][15][16][17][18] However, prevention of PJK remains unsolved and is still a relatively common postoperative complication.…”

Section: Introductionmentioning

confidence: 99%

Can Machine Learning Accurately Predict Postoperative Compensation for the Uninstrumented Thoracic Spine and Pelvis After Fusion From the Lower Thoracic Spine to the Sacrum?

Lee

Sardar

Boddapati

et al. 2020

Global Spine Journal

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Study Design: Consecutively collected cases. Objective: To determine if a machine-learning (ML) program can accurately predict the postoperative thoracic kyphosis through the uninstrumented thoracic spine and pelvic compensation in patients who undergo fusion from the lower thoracic spine (T10 or T11) to the sacrum. Methods: From 2015 to 2019, a consecutive series of adult (≥18 years old) patients with adult spinal deformity underwent corrective spinal fusion from the lower thoracic spine (T10 or T11) to the sacrum. Deidentified data was processed by a ML system-based platform to predict the postoperative thoracic kyphosis (TK) and pelvic tilt (PT) for each patient. To validate the ML model, the postoperative TK (T4-T12, instrumented thoracic, and uninstrumented thoracic) and the pelvic tilt were compared against the predicted values. Results: A total of 20 adult patients with a minimum 6-month follow-up (mean: 22.4 ± 11.3 months) were included in this study. No significant differences were observed for TK (predicted 37.6° vs postoperative 38.3°, P = .847), uninstrumented TK (predicted 33.9° vs postoperative 29.8°, P = .188), and PT (predicted 23.4° vs postoperative 22.7°, P = .754). The predicted PT and the TK of the uninstrumented thoracic spine correlated well with postoperative values (uninstrumented TK: R 2 = 0.764, P < .001; PT: R 2 = 0.868, P < .001). The mean error with which kyphosis through the uninstrumented thoracic spine can be measured was 4.8° ± 4.0°. The mean error for predicting PT was 2.5° ± 1.7°. Conclusion: ML algorithms can accurately predict the spinopelvic compensation after spinal fusion from the lower thoracic spine to the sacrum. These findings suggest that surgeons may be able to leverage this technology to reduce the risk of proximal junctional kyphosis in this population.

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Section: Introductionmentioning

confidence: 99%

Can Machine Learning Accurately Predict Postoperative Compensation for the Uninstrumented Thoracic Spine and Pelvis After Fusion From the Lower Thoracic Spine to the Sacrum?

Lee

Sardar

Boddapati

et al. 2020

Global Spine Journal

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show abstract

“…Depending on the definition employed in previous studies, the incidence of PJK varies between 14% and 46 %. [4][5][6][7][8][9][10][11] The big variation in literature comes from having studies analyzing different types of scoliosis, such as AIS, neuromuscular or adult spinal deformities. Different and more risk factors have been identified in adults and patients with neuromuscular scoliosis than in patients with idiopathic scoliosis.…”

Section: Discussionmentioning

confidence: 99%

“…[2,3] One of the currently most discussed problems is Proximal Junctional Kyphosis (PJK), a radiological finding that can manifest itself in the clinical problem of Proximal Junctional Failure. Depending on the used definition of PJK the incidence varies between 14 and 46 % [4][5][6][7][8][9][10][11] with a revision rate of about 10%. [12] The etiology of PJK seems to be multifactorial and has not yet been conclusively clarified.…”

Section: Introductionmentioning

confidence: 99%

“…[6,13,14] In addition, it was recently shown that two interesting parameters representing the spine's sagittal alignment at the proximal part of the instrumentation, namely the rod contouring angle (RCA) and its mismatch with the proximal junctional angle (PJA), are associated with the occurrence of PJK. [15,16] Decreased RCA, representing the amount of kyphotic curvature bent into the rod, has been suggested to be a risk factor for PJK, but the importance of a mismatch between PJA and RCA (PJA-RCA) has not been fully understood and has rarely been studied in AIS. [15] Furthermore, spinous processes are often sacrificed during posterior surgery harvesting cancellous bony material for spondylodesis.…”

Section: Introductionmentioning

confidence: 99%

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Risk Factors of Proximal Junctional Kyphosis in Adolescent Idiopathic Scoliosis – the Spinous Processes and Proximal Rod Contouring

Boeckenfoerde¹,

Boevingloh²,

Gosheger³

et al. 2022

Preprint

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Proximal Junctional Kyphosis (PJK) as one of the most discussed problems after corrective surgery in adolescent idiopathic scoliosis (AIS), is still not fully clarified and seems to be multifactorial. Biome-chanical and few clinical studies have shown the influence of destruction of posterior ligaments by re-section of spinous processes and some parameters concerning rod contouring as risk factors for PJK. To verify these results 192 patients with AIS and corrective surgery via posterior approach between 2009 and 2017 were included. Radiographic parameters were analyzed preoperatively (preOP), postoperatively (postOP), and with a mean follow up (FU) of 27 months. The participants were divided into two groups (PJK group and non-PJK group). The incidence of PJK was 15.6%. Contrary to the results of biomechanical studies, we could not find any significant influence of the spinous process resection. However, the PJK group had significantly larger preOP T4-T12 kyphosis (31.1°±13.93° vs. 23.3°±14.93°, p=.016). Furthermore, the PJK group showed a significantly larger rod contour angle (RCA) (8.0°±4.44° vs. 5.9°±3.28°, p=.003) and mismatch of postOP proximal junctional angle (PJA) and RCA (3.5°±5.72° vs. 0.9°±4.86°, p=.010) compared to the non-PJK group. An increase of the mismatch of postOP PJA and RCA (OR=1.14, p=.008) and a high RCA are risk factors for PJK and need to be focused on by surgeons.

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“…Yan [ 16 ] demonstrated that mismatch between postoperative PJA and PRCA led to a proximal compensation, namely PJK in degenerative scoliosis. After reviewing 84 adolescent idiopathic scoliosis patients, Wang et al [ 24 ] found that larger postoperative PJA-PRCA, especially those with PJA-PRCA greater than 5° were risk factors for PJK.…”

Section: Discussionmentioning

confidence: 99%

Unmatched rod contouring at the proximal end predisposes to occurrence of junctional kyphosis in early-onset scoliosis patients undergoing traditional growing rods treatment

Yang

Wang

et al. 2022

BMC Musculoskelet Disord

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Study design A retrospective case series. Objective To investigate whether unmatched rod contouring at the proximal end predisposed to the occurrence of proximal junctional kyphosis (PJK) in early-onset scoliosis (EOS) patients after traditional growing rods (TGR) treatment. Summary of background data TGR treatment has become a mainstay of treatment for EOS patients. PJK is one of the most common alignment-related complications. Methods A consecutive series of EOS patients who had undergone TGR treatment were retrospectively reviewed. They were divided into PJK and non-PJK groups according to the occurrence of PJK or not. Demographic data, surgical strategies, and radiographic parameters were recorded and compared between groups. Proximal junctional angle (PJA) was defined as the angle between the caudal endplate of the UIV and the cephalad endplate of the second supradjacent vertebra above the UIV, while proximal rod contouring angle (PRCA) was defined as the angle of proximal rod contouring, which was represented by the angle between the cephalad endplate of the UIV and the caudal endplate of the second vertebra caudal to the UIV. Unmatched proximal rod contouring was regarded if the postoperative PRCA-PJA difference was greater than 5°. Results This study finally included 73 patients. The mean age at the index surgery was 6.5 ± 2.2 years (range, 2–10 years). Mean follow-up lasted 5.0 ± 1.7 years (range, 2–9 years). They received mean 4.6 ± 1.6 lengthening procedures. There were 13 patients who were observed with PJK (18%). In comparison with the non-PJK group, the PJK group showed a larger preoperative major curve (82 ± 21° vs 70 ± 17°, P = 0.041) and global kyphosis (57 ± 6° vs. 44 ± 15°, P = 0.044). In addition, the PJK group had significantly larger postoperative PJA (10 ± 3 vs. 5 ± 3, P<0.001) and greater postoperative PJA-PRCA (6 ± 3 vs. 3 ± 3, P = 0.031). The proportion of patients with unmatched proximal rod contouring in PJK group was significantly higher than that in the non-PJK group (69% vs. 25%). Multiple logistic regression showed that preoperative GK>50°, postoperative PJA>10 and postoperative unmatched proximal rod contouring were the risk factors in predicting PJK after TGR treatment. Conclusion Approximately 18% EOS patients experienced PJK after TGR treatment. Unmatched proximal rod contouring may be an independent risk factor of PJK occurrence, in addition to greater preoperative GK and larger postoperative PJA. Level of evidence 3.

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Large Difference Between Proximal Junctional Angle and Rod Contouring Angle is a Risk Factor for Proximal Junctional Kyphosis

Cited by 19 publications

References 20 publications

Can Machine Learning Accurately Predict Postoperative Compensation for the Uninstrumented Thoracic Spine and Pelvis After Fusion From the Lower Thoracic Spine to the Sacrum?

Can Machine Learning Accurately Predict Postoperative Compensation for the Uninstrumented Thoracic Spine and Pelvis After Fusion From the Lower Thoracic Spine to the Sacrum?

Risk Factors of Proximal Junctional Kyphosis in Adolescent Idiopathic Scoliosis – the Spinous Processes and Proximal Rod Contouring

Unmatched rod contouring at the proximal end predisposes to occurrence of junctional kyphosis in early-onset scoliosis patients undergoing traditional growing rods treatment

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