Akosman Izzet, Hirase Takashi, Chow Jarred Lihan, Subramanian Tejas, Uzzo Robert, Jones Charlotte Henry, Persaud Steven Govinda, Demopoulos Bryce, Tuma Olivia, Cunningham Matthew, Kim Han Jo, Lovecchio Francis
Hospital for Special Surgery, New York, NY.
Weill Cornell Medicine, New York, NY.
Spine (Phila Pa 1976). 2025 Apr 1;50(7):485-492. doi: 10.1097/BRS.0000000000005096. Epub 2024 Jul 19.
Systematic review.
To describe the various definitions of PJK and PJF used in spinal deformity literature and their utility over time.
Proximal junctional kyphosis or failure (PJK/PJF) is among the most common complications after long-segment fusions, but there is no consensus on their definitions. This presents challenges in understanding risk factors, management, and prevention strategies.
A systematic literature review was performed on studies specifying a definition of PJK and/or PJF. PJK definitions were categorized as radiographic versus nonradiographic, and data were collected on PJK criteria, including the threshold for proximal junctional angle (PJA), change in PJA, vertebra selection for PJA measurement, and follow-up time points. PJF definitions were categorized as structural failure, need for revision, symptomatic failure, and radiographic (angular).
A total of 359 studies defining PJK and/or PJF were identified. While 56% of studies used the definition PJA>10 ° and PJA change from baseline>10 ° , the remainder expressed significant heterogeneity with respect to criteria for the magnitude of PJA and degree of PJA change. The most common vertebrae assessed were UIV/UIV+2 (74%), and the most common minimum follow-up (mFU) listed was two years (60%). Mean FUs for studies varied considerably even in studies with the same mFU, from 2.1 to 8.9 years (2-yr mFU) and 1.1 to 4.0 years (1-yr mFU). PJF definitions were most commonly structural (58%) or defined as a need for revision (48%), with a much less common use of PJA thresholds (23%).
The challenges faced in preventing proximal junctional complications are mired in the heterogenous groundwork by which PJK and PJF are defined. Most definitions of PJK use radiographic thresholds without consideration of clinical relevance and variations in individual alignment. Conversely, definitions of PJF are based on clinical criteria, which are often subjective. Future research should focus on understanding the mechanisms of PJK/PJF, as only then will we be able to accurately define and prevent these complications.
系统评价。
描述脊柱畸形文献中使用的近端交界性后凸（PJK）和近端交界性失败（PJF）的各种定义及其随时间的效用。
近端交界性后凸或失败（PJK/PJF）是长节段融合术后最常见的并发症之一，但对其定义尚无共识。这给理解危险因素、管理和预防策略带来了挑战。
对明确PJK和/或PJF定义的研究进行系统的文献综述。PJK定义分为影像学定义和非影像学定义，并收集有关PJK标准的数据，包括近端交界角（PJA）阈值、PJA变化、PJA测量的椎体选择以及随访时间点。PJF定义分为结构失败、翻修需求、症状性失败和影像学（角度）定义。
共确定了359项定义PJK和/或PJF的研究。虽然56%的研究使用PJA>10°且PJA相对于基线变化>10°的定义，但其余研究在PJA大小标准和PJA变化程度方面表现出显著的异质性。评估的最常见椎体是上位融合椎（UIV）/UIV+2（74%），列出的最常见最短随访时间（mFU）是两年（60%）。即使在具有相同mFU 的研究中，各研究的平均随访时间差异也很大，2年mFU的研究中为2.1至8.9年，1年mFU的研究中为1.1至4.0年。PJF定义最常见的是结构方面的（58%）或定义为需要翻修（48%），使用PJA阈值的情况则少得多（23%）。
预防近端交界性并发症面临的挑战因PJK和PJF定义的异质性基础而陷入困境。大多数PJK定义使用影像学阈值，而未考虑临床相关性和个体对线情况。相反，PJF定义基于临床标准，而这些标准往往是主观的。未来的研究应专注于了解PJK/PJF的机制，只有这样我们才能准确地定义和预防这些并发症。
