Mechanical Complications in Adult Spine Deformity Surgery: Retrospective Evaluation of Incidence, Clinical Impact and Risk Factors in a Single-Center Large Series

Abstract

The advancement of deformity-specific implants and surgical techniques has improved the surgical treatment of Adult Spine Deformity (ASD), allowing surgeons to treat more complex deformities. Simultaneously, high rates of medical and surgical complications have been reported. The aim of this study is to describe the risk factors, the rate and the clinical impact of mechanical complications in ASD surgery. A retrospective review of a large, single-center database of consecutive ASD patients was conducted. Inclusion criteria were as follows: Cobb coronal curve > 20° or alteration of at least one of sagittal vertical axis (SVA > 40 mm), thoracic kyphosis (TK > 60°), pelvic tilt (PT > 20°) and pelvic incidence minus lumbar lordosis mismatch (PI-LL > 10°), at least four levels of posterior instrumented fusion and 2-year follow-up. At the baseline and at each follow-up end point, the authors collected clinical and radiographic outcomes and recorded any mechanical complications that occurred. One hundred and two patients were enrolled. Clinical outcomes significantly were improved at the last follow-up (mean 40.9 months). Postoperative mechanical complications occurred in 15 patients (14.7%); proximal junctional disease was the most common complication (60%) and the revision rate was 53.3%. Patients who experienced mechanical complications were older (61.2 vs. 54.8 years, p = 0.04); they had also a higher rate of pelvic fusion and posterior-only approach, a lower LL (−37.9 vs. −46.2, p = 0.02) and a higher PT (26.3 vs. 19.8, p = 0.009), TK (41.8 vs. 35.7, p = 0.05), PI–LL (12.9 vs. 5.4, p = 0.03) and Global Alignment and Proportion score (6.9 vs. 4.3, p = 0.01). This study showed a significant improvement in pain and disability after ASD surgery. Regarding the risk of developing a mechanical complication, not only postoperative radiographic parameters affected the risk but also patient age and surgical features.

The Clinical Impact of Failing to Achieve Ideal Proportional Realignment in Adult Spinal Deformity Patients

“…Despite advancements in surgical technique and perioperative management over the last two decades, postoperative morbidity and longer-term mechanical failure remain common events in patients receiving surgery for adult spinal deformity (ASD). 2–6…”

“…Despite advancements in surgical technique and perioperative management over the last two decades, postoperative morbidity and longer-term mechanical failure remain common events in patients receiving surgery for adult spinal deformity (ASD). [2][3][4][5][6] Preoperative surgical planning for ASD patients focuses on an individualized, patient-tailored approach to realignment, recently incorporating age into the sagittal alignment goals. 1,7 There have been multiple major systems proposed within the last decade, including the Scoliosis Research Society (SRS)-Schwab classification system, age-adjusted alignment ideals, and the Roussouly spinal shape classification.…”

“…In the original study, patients proportioned in GAP have demonstrated mechanical complication rates as low as 6%, substantially lower than those found to be moderately or severely disproportioned on the GAP scale. 4,5,10 Although this method was initially established to predict mechanical complications, we hypothesize this score may also be predictive of other postoperative adverse events.…”

Preoperative Malnutrition-Associated Spinal Malalignment with Patient-Reported Outcome Measures in Adult Spinal Deformity Surgery: A 2-Year Follow-Up Study

“…Higher BMI, older age, osteoporosis, and radiographic parameters are risk factors [16][17][18] . Rod breakage may cause severe pain and loss of correction, frequently requiring revision surgery 19) .…”

Long-term Morbidity in Patients After Surgical Correction of Adult Spinal Deformity

“…With advances in modern surgical techniques, 1,2 adult spinal deformity (ASD) correction has been shown to lead to significant improvement in patient functionality and quality of life 3,4 . However, the durability of ASD surgery remains a clinical challenge, 5,6 and has been associated with high rates of intraoperative and postoperative complications 7–9 …”