Study Design.

A retrospective cohort study.

Objectives.

The aim of this study was to evaluate radiographic and patient-reported outcomes at minimum 2 years after revision surgery for proximal junctional kyphosis (PJK), correlating these results with PJK etiology.

Summary of Background Data.

There are no studies detailing the results of revision surgery for PJK following posterior segmental instrumentation.

Methods.

Thirty-two consecutive patients treated with revision surgery after PJK above posterior fusions (25 women/7 men, average age at surgery 60.6 yrs) were reviewed for radiographic and patient-reported outcomes (mean follow-up, 4.5 yrs; range, 2–10 yrs). Patients were subdivided into fracture (F) and nonfracture (NF) groups on the basis of PJK etiology.

Results.

Radiographic severity of PJK improved significantly with revision surgery and was maintained at ultimate follow-up (P< 0.001). However, initial sagittal vertical axis (SVA) correction was not maintained through ultimate follow-up (P= 0.04). There were significant postrevision improvements in mean Oswestry scores (P< 0.001) and SRS total scores (P< 0.001) in all patients. In patients with pelvic incidence-lumbar lordosis (PI-LL) mismatch< 11, final PJK measurement was smaller than in patients with mismatch≥ 11 (9.4 vs. 19.8, P= 0.009). Six patients (19%) developed new postrevision PJK, with two (6%) requiring additional surgery. Patients who sustained PJK through a fracture had greater improvements in Oswestry (P= 0.004), total SRS (P= 0.04), pain (P< 0.001), and satisfaction (P= 0.05) scores, although the fracture patients had less maintained SVA correction (P= 0.002).

Conclusion.

Revision surgery for PJK following posterior instrumentation achieved acceptable radiographic and clinical outcomes at minimum 2-year follow-up. Patients with PI-LL mismatch< 11 experienced more ultimate PJK correction than patients with mismatch≥ 11. Although the NF group experienced more sustained correction of sagittal balance, the F group reported greater improvements in patient-reported outcomes. Ultimate clinical outcomes after revision surgery for PJK were similar between patients with and without compression fractures.

Level of Evidence: 3

Adjacent segment pathology after spinal deformity surgery remains one of the greatest challenges in treating adult spinal deformity. The incidence of adjacent segment pathology requiring revision surgery has been cited as up to 27% following adult deformity surgery. 1–4 Proximal junctional kyphosis (PJK) after a long thoracolumbar fusion is of particular concern, due to its multifactorial causes and risk of neurologic injury to the cervicothoracic spinal cord. Patients undergoing revision spine fusions are at a greater risk for complications, so identifying which patients will most benefit from a revision procedure is paramount. In addition, if a patient's fusion is extended proximally due to PJK, the risk of recurrent PJK at this new upper instrumented vertebra (UIV) remains.