Proximal Junctional Kyphosis Following Long Instrumented Spinal Fusion: The Effect of Implant Selection

Proximal Junctional Kyphosis Following Long Instrumented Spinal Fusion: The Effect of Implant Selection

The treatment of adult deformity has improved with the development and use of modern segmental instrumentation, including posterior instrumentation. However, the incidence of proximal junctional kyphosis (PJK) caused by the accelerated degeneration of the joint capsules and smaller articular processes in the proximal junctional region has also been noted.

One potential way of decreasing PJK is to decrease the structural rigidity of the construct at the top thereby providing a transition to the non-instrumented spine and allowing for less facet capsule and muscle disruption.

While a possible solution to PJK is to reduce structural rigidity at the top of the construct, there is a need to investigate it. In the proposed study, the investigators will compare the rate of proximal junctional kyphosis in patients treated with a stainless steel rod (REVERE Stabilization System) versus those treated with TRANSITION Stabilization System.

Patient outcome measures (Scoliosis Research Society (SRS-22), SF12 and ODI) and radiographic measurements (including lumbar lordosis (L1-S1), adjacent segment kyphosis, thoracolumbar kyphosis (T10-L2), sagittal balance, sacral slope, and pelvic incidence) will be analyzed.

Inclusion Criteria:

• Adult patients with degenerative spondylolisthesis with objective evidence of neurologic impairment, kyphosis, and failed previous fusion (pseudoarthrosis) requiring treatment with an instrumented posterior fusion from the thoracolumbar junction (T10-L1) to the sacrum
• At least 18 years of age and maximum 70 years of age
• Ability to provide Informed Consent for study participation and patients to return for all follow-up visits

Exclusion Criteria:

• Presence of systemic or localized infection
• Previous fusion attempt at the involved level(s)
• More than three previous open, posterior, lumbar spinal surgical procedures at the involved level(s)
• Trauma at the levels to be fused
• Previous documentation of osteopenia or osteomalacia
• Diagnosis of a condition or requires postoperative medication(s), which may interfere with bony/soft tissue healing
• Presence of a disease entity or condition which totally precludes possibility of bony fusion (e.g. metastatic cancer, HIV, long term use of steroids, etc.)
• Immunosuppressive disorder
• Pregnancy
• History of alcohol and/or drug abuse
• Any known allergy to a metal alloy
• Mentally incompetent or prisoner
• Currently a participant in another study
• Preoperative structural deformity in the thoracic spine (kyphosis >60 degrees, Coronal curve >40 degrees)
• Circumferential fusion above L1