Instrumentation Techniques to Prevent Proximal Junctional Kyphosis and Proximal Junctional Failure in Adult Spinal Deformity Correction: A Systematic Review of Clinical Studies

Abstract

Study Design: Systematic review. Objectives: To summarize the results of clinical studies investigating spinal instrumentation techniques aiming to reduce the postoperative incidence of proximal junctional kyphosis (PJK) and/or failure (PJF) in adult spinal deformity (ASD) patients. Methods: EMBASE and Medline® were searched for articles dating from January 2000 onward. Data was extracted by 2 independent authors and methodological quality was assessed using ROBINS-I. Results: 18 retrospective- and prospective cohort studies with a severe or critical risk of bias were included. Different techniques were applied at the upper instrumented vertebra (UIV): tethers in various configurations, 2-level prophylactic vertebroplasty (2-PVP), transverse process hooks (TPH), flexible rods (FR), sublaminar tapes (ST) and multilevel stabilization screws (MLSS). Compared to a pedicle screw (PS) group, significant differences in PJK incidence were found using tethers in various configurations (18% versus 45%, P = 0.001, 15% versus 38%, P = 0.045), 2-PVP (24% vs 36%, P = 0.020), TPH (0% vs. 30%, P = 0.023) and FR (15% versus 38%, P = 0.045). Differences in revision rates for PJK were found in studies concerning tethers (4% versus 18%, P = 0.002), 2-PVP (0% vs 13%, P = 0.031) and TPH (0% vs 7%, P = n.a.). Conclusion: Although the studies are of low quality, the most frequently studied techniques, namely 2-PVP as anterior reinforcement and (tensioned) tethers or TPH as posterior semi-rigid fixation, show promising results. To provide a reliable comparison, more controlled studies need to be performed, including the use of clinical outcome measures and a uniform definition of PJF.

Percutaneous Vertebroplasty and Upper Instrumented Vertebra Cement Augmentation Reducing Early Proximal Junctional Kyphosis and Failure Rate in Adult Spinal Deformity: Case Series and Literature Review

“…Multiple in vivo studies have gone on to use this surgical technique in long-segment fusions. [15][16][17][18][19][20][21][22] In our literature search, we found 4 retrospective studies, 15,17,19,20 2 prospective studies, 16,18 and 2 systematic reviews 21,22 regarding PVP in the prevention of adjacent segment disease. Of these, Raman et al 18 had the largest cohort of patients treated with cement augmentation at the UIV and rostral adjacent vertebra (UIV + 1) with a total of 39 patients.…”

“…There are numerous reported modalities used to help prevent PJK/ PJF, such as 2-level prophylactic vertebroplasty (PVP) at the UIV and UIV + 1. [15][16][17][18][19][20][21][22] In this study, we report the largest current series of prophylactic cement augmentation with UIV + 1 vertebroplasty and an updated literature review. This was a cohort analysis and not a case-control study.…”

Failure in Adult Spinal Deformity Surgery

“…PJK and PJF are common mechanical complications following ASD surgery and have been extensively studied and reviewed. [112][113][114] The incidence of PJK following ASD surgery has been investigated in several studies and review series, and is estimated to occur in 20% to 50% of cases [114][115][116][117][118] (Table 4). A recent metaanalysis of 2215 unique patients across 14 studies found that the primary risk factors for PJK included: older age, long-segment fusion to the rigid spine (sacrum/ilium), a large thoracic kyphotic angle, osteoporosis, and sagittal malalignment.…”

“…Accordingly, several investigators have focused on risk-reduction techniques to prevent PJK, which generally fall into three categories: (1) implementing tailored surgical plans, (2) instrumentation techniques, and (3) augmentation and preservation of the posterior tension band. 112,113,121,127 First, several studies have suggested that excess LL in ASD correction predisposes to higher PJK risks. 119 Ageappropriate correction of sagittal malalignment has been proposed as a means of reducing PJK risk.…”

“…PJK refers to the radiographic phenomenon of the tendency of the levels above the upper-most instrumented vertebra (UIV) to fall into kyphosis relative to the UIV itself, such that the angle between the lower endplate of the UIV and the upper endplate of the UIV+2 is >10° or >10° of the preoperative angle. PJK and PJF are common mechanical complications following ASD surgery and have been extensively studied and reviewed 112–114. The incidence of PJK following ASD surgery has been investigated in several studies and review series, and is estimated to occur in 20% to 50% of cases114–118 (Table 4).…”