Different types of mechanical complications after surgical correction of adult spine deformity with osteotomy

AIM To determine the incidence and risk factors for mechanical complications （MC） after surgical correction of adult spinal deformity （ASD） with osteotomy.METHODSA retrospective study was performed. Inclusion criteria： Surgical correction of ASD using osteotomy; male or female; 〉 20 years old; follow-up ≥ 24 mo or revision. The MC of spine and spinal instrumentation were studied separately. Risk analysis included assessment of the association between more than 50 different characteristics （demographic, clinical, radiographic, and instrumentation） with different types of MC.RESULTSThe medical records of 94 operations in 88 subjects were analyzed： Female （68%）, mean age 58.6 （SD, 12.7） years. Cumulative incidence of MC at 2 year follow-up was 43.6%. Of these, 78% required revision （ P 〈 0.001）. The following characteristics had significant （ P ≤ 0.05） association with MC： （1） Preoperative： osteoporosis, smoking, previous spinal operation, sagittal vertical axis （SVA） 〉 100 mm, lumbar lordosis （LL） 〈 34°; （2） postoperative： SVA 〉 75 mm; operative correction： SVA 〉 75 mm, LL 〉 30°, thoracic kyphosis 〉 25°, and pelvic tilt 〉 9°; a fall; pseudarthrosis; and （3） device and surgical technique： use of previously implanted instrumentation; use of domino and/or parallel connectors; type of osteotomy （PSO vs SPO） if preoperative SVA 〈 100 mm; lumbar osteotomy location; in-situ rod contouring 〉 60°; and fxation to sacrum/pelvis.CONCLUSIONRisk of MC after surgical correction of ASD is substantial. To decrease this risk over- and/or insuffcient correction of the sagittal imbalance should be avoided.

Adjacent Segment Disease after Long Spinal Fusion Ending at L5 for Adult Spinal Deformity: A Retrospective Cohort Study

Study Design: This is a retrospective cohort study using data from the adult spinal deformity (ASD) database of a single institution. Purpose: To investigate the incidence of proximal junctional failure and distal junctional failure (DJF) after ASD surgery with a lower instrumented vertebra (LIV) at L5. Overview of Literature: Spinopelvic fixation from the lower thoracic vertebra to the pelvis is the current gold standard treatment for ASD. However, the LIV at L5 is acceptable in some cases. Methods: Fifty-six patients who underwent corrective surgery for ASD with LIV at L5 were included. The upper instrumented vertebra (UIV) was T7 in one patient, T9 in 14, T10 in three, T11 in four, T12 in eight, L1 in 10, and L2 in 16. Regarding clinical parameters, age, sex, curve types of Scoliosis Research Society-Schwab classification, number of levels fused, follow-up period, hip bone mallow density, revision surgery rate, and radiographic measurements were compared between the T (UIV: T7 - 10) and TL (UIV: T11 - L2) groups. Results: The revision surgery rate was 19.6% overall. In the T and TL groups, it was 27.8%, and 15.8%, respectively (p = 0.305). The rate of DJF in the T group (33.3%) was significantly higher than in the TL group (5.3%). The rate of proximal junctional kyphosis in the T group (55.6%) was higher than in the TL group (28.9%), with no significant difference. The mean global alignment, sagittal vertical axis, and C7 plumb line-central sacral vertical line were not different between both groups. Conclusions: ASD surgery with LIV set at L5 and UIV set at the thoracic vertebrae (T7 - T10) has a risk of adjacent segment disease.