Long-term follow-up of AIS surgical treatment reveals “less than ideal” results

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scoliosis_featuredAn analysis of ≥10 year outcomes data for patients treated surgically for major thoracic adolescent idiopathic scoliosis (AIS) has found that 23% of the surgical outcomes in this cohort were “less than ideal”. The prospective study from the Harms Study Group sought to critically assess changes in radiographic and patient-reported outcomes from preoperative to longer-term postoperative follow-up, and evaluate factors associated with less desirable outcomes and understand the impact on patients.

The team, led by Peter Newton (San Diego, USA), enrolled patients in this institutional review board, multicentre study from 1995 onwards. Data was analysed for 92 patients who were treated surgically for AIS major thoracic curves (Lenke 1-4), and who had completed at least 10 years’ follow-up. The data was presented at the Scoliosis Research Society Annual Meeting (SRS; 21-24 September 2016, Prague, Czech Republic) by co-author, Michelle Claire Marks. The purpose of the study was to “understand the factors associated with less desirable outcomes and the impact on patients,” according to Marks.

Thirty-nine patients were treated via a posterior approach, 36 thorascopic anterior, and 17 open anterior. The researchers reviewed complications and perioperative data, radiographs and Scoliosis Research Society (SRS) questionnaire results, evaluating changes in coronal and sagittal radiographic parameters) and SRS-24 questionnaire scores.

To define “less than ideal” radiographic results, 10 surgeons rated X-rays according to concern for revision due to loss of fixation, implant failure and/or deformity progression. A majority consensus would classify an X-ray as “less than ideal”. Cases in which revision surgery had already been performed were also deemed “less than ideal”.

The authors found significant improvements in thoracic Cobb (52 to 25 degrees), coronal balance (1.8 to 0.9cm) and thoracic kyphosis (20 to 25 degrees). However, proximal junctional kyphosis showed a slight increase (4.8 to 7.6 degrees) in the pre- to 10 year postoperative results.

Surgeons rated 69 of the sets of radiographic results as “ideal”, with no consensus on two. Of the 21“less than ideal” sets of results, 11 were due to implant failures/pseudoarthritis, eight to residual/deformity progression, one to a misplaced implant and one due to infection. Revision surgery had been performed in seven of the “less than ideal” cases. Four of these surgeries had been performed before two years post-procedure, with one occurring at four years, one at seven years, and one at eight years post-procedure. The percentage of “less than ideal” outcomes in each of the surgical approaches (posterior, thoracoscopic anterior, open anterior) were not statistically different (p=0.33).

Radiographic comparison of the “ideal” versus “less than ideal” patient groups revealed the “less than ideal” patients had significantly greater thoracic curves at 10 years. They also had greater preoperative thoracic kyphosis, which remained significantly greater at 10 years.

With regards to average SRS scores, the “ideal” and “less than ideal” groups were similar preoperatively, but at 10 years the “less than ideal” patients had lower scores in self-image, function, total score and satisfaction.

“This cohort of 10 year follow-up was limited by a 20-25% follow-up rate,” Marks told Spinal News International. “However, 
we can still learn from evaluating the poor outcomes that were uncovered.”

The authors concluded this prospectively collected cohort of 10 years of follow-up revealed a 8% revision rate.Twenty-three per cent of the 10 year outcome radiographs were graded as ‘less than ideal’, which were associated with less correction in the thoracic curve and failure to restore the thoracic sagittal profile, which impacts 
patients by poorer self-image, reduced function and decreased satisfaction.

“We remain hopeful that our advancements in improved surgical techniques and decision-making will help us reduce these less-than-ideal outcomes in the future,” Marks concluded. “Our patients deserve this ongoing critical analysis of long-term prospectively-collected outcomes.”

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