(HealthDay News) − Pre-existing and perioperative factors may trigger proximal junctional kyphosis (PJK) in about 22% of patients with adult idiopathic scoliosis who undergo long instrumented spinal fusion surgery.

To evaluate the incidence and risk factors of PJK, Mitsuru Yagi, MD, PhD, of the Hospital for Special Surgery in New York City, and associates conducted a retrospective review of the charts and X-rays of 76 consecutive patients (mean age, 48.8 years) who underwent long instrumented spinal fusion. Radiographic measurements and demographic data were reviewed before surgery, immediately after surgery, at two- and five-years post-surgery, and at follow-up (average 7.3 years).

The researchers identified PJK in 17 patients, 76% of whom were identified within three months of surgery. Fifty-three percent of the total PJK was progressed within three months of surgery, and progression continued until the final follow-up. There were no significant differences between the PJK and non-PJK groups in the Scoliosis Research Society Patient Questionnaire (SRS) scores and Oswestry Disability Index (ODI). Significant risk factors for PJK were pre-existing low bone mineral density (BMD), posterior spinal fusion (PSF), fusion to sacrum, inappropriate global spine alignment, and greater sagittal vertical axis change.

“No significant differences were found in SRS outcome scores and ODI between PJK and non-PJK patients. Pre-existing low BMD, PSF, and fusion to sacrum were identified as risk factors,” the authors write. “PJK can be minimized by postoperative normalization of global spine alignment and balance.”

One of the authors disclosed financial ties to the medical device industry.

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