Background: Adult spinal deformity (ASD) is a disorder characterized by abnormal curvature of the spine resulting from progressive degeneration of spinal elements. Although operative intervention for ASD is commonplace, it is associated with several complications, including proximal junctional kyphosis (PJK) and proximal junctional failure (PJF). The objective of this review is to outline the role of proximal fixation in preventing PJK and PJF.
Methods: We conducted a literature search using the Embase, Scopus, Web of Science, CINHAL, Cochrane Library, and PubMed MEDLINE databases. We considered only studies focusing on adult patients and selected clinical studies investigating proximal fixation techniques.
Results: There was mixed evidence of the efficacy of hooks and other instrumentation methods in preventing PJK, although most studies supported the use of hooks. Selection of lower thoracic vertebrae was associated with higher rates of PJK and PJF in several studies, although the relationship was inconsistent, and many studies reported no significant difference in rates of PJK or PJF between different upper instrumented vertebra (UIV) levels. Other techniques that are not related to specific instrumentation or vertebral selection, such as adjusting UIV screw trajectory, were also referenced. However, the evidence supporting these techniques was limited.
Discussion: Despite the presence of numerous studies in the literature discussing proximal fixation strategies to reduce the incidence of PJK/PJF, the lack of prospective studies and high variability in study methods make direct comparison challenging. We could not draw strong conclusions regarding the superiority of any one technique, despite promising clinical results with a strong biomechanical basis in several studies.
Clinical relevance: This systematic literature review showed that a variety of proximal fixation techniques have been used to prevent PJK/PJF without clear evidence in favor of any particular technique.
Keywords: outcomes; prevention; proximal junctional kyphosis.
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