Paul Sponseller, president of the Scoliosis Research Society (SRS) 2019–2020, talks to Spinal News International about the society’s 54th annual meeting (18–21 September, Montreal, Canada), which attracted over 1,400 attendees from around the world.
The conference began with a pre-course, “Improving Patient Outcomes through Peak Surgeon Performance”. Using examples from the aerospace industry, the speakers discussed the importance of team attitudes, the use of dashboards in MOC, AIS, CP and adult deformity. Hospital and payors may increasingly be keeping dashboards on surgeon performance.
One hundred and seventy one papers were presented from the podium, covering all aspects of spine deformity. Vertebral Body Tethering was the topic of several papers: Results of anterior vertebral body tethering at skeletal maturity in 14 patients were presented by Ahmet Alanay. Starting with a mean 46 degree curve, main thoracic curve correction was 78% at maturity. Pulmonary function improved. Over-correction occurred in Sanders 2 patients. Pulmonary function improved by maturity. Parent et al compared HRQoL scores between fusion and anterior VBT. Both groups improved over the preoperative scores. They showed that patients with VBT, who were slightly younger and start with better HRQoL Scores, maintain this slight difference at final follow up although the gap narrows slightly. Samdani presented the results of an FDA IDE study with a minimum of 2 (mean=3) year follow up. Their indications were Lenke 1 A or B curves of 30–65 degrees. At follow up, 85% of major curves were less than 30 degrees. Kyphosis did not increase but remained stable. Revision rate was 9.4%, mostly due to over-correction. There were no neurologic complications. Further refinement of the indications, improvement of the prediction of growth, and longer term follow up of this technique is suggested.
Spinal fusion for AIS with posterior segmental instrumentation and pedicle screw constructs is currently the mainstay of treatment. There is variability in the implant density used by different surgeons. It is not known whether higher implant density adds important corrective ability, freedom from re-instrumentation, or has disadvantages. Larson presented the results of a prospective randomised study of implant density for Lenke 1A curves of up to 65 degrees (the MIMO study—Minimise implants, maximise outcomes). Patients were randomised to a mean anchor density of greater than 1.8 screws per level versus less than 1.4 screws per level. At two-year follow-up, they found no significant difference in coronal or sagittal curve correction, blood loss, or reoperation rate. The authors concluded that lower implant density represents an opportunity for cost savings with no apparent loss of quality in patients with this type of curve.
Skeletal maturity assessment is important for surgical decision making. Risser sign is not informative about peak height velocity. Although the hand is increasingly used for scoring, it requires a separate radiograph. Smith received the Hibbs award for best clinical paper, “Using humerus ossification and Cobb angle to predict progression to surgery in scoliosis patients”. The proximal humerus is often visible in the scoliosis radiograph, and undergoes characteristic changes as the epiphysis widens to match the metaphysis, develops a “J” shape, and then narrows and fuses. Using serial radiographs to maturity or surgery, he showed that the risk of progression to surgery can be quantified by the equation, risk = 10- (cobb angle x humeral score).
Quality improvement studies were also a feature of the meeting. In his paper, “Promising but imperfect: The effectiveness of quality programs for Surgical site Infections in Pediatric Spinal Surgery Diminishes over Time”, Vitale showed that decreases in infection incidences occurred in all diagnostic subcategories but the incidence increased again as time from implementation increased. This phenomenon was seen in congenital, neuromuscular, and syndromic scoliosis. There was no decline in infection rates for idiopathic scoliosis. The authors called for strategies to insure both adherence to and the effectiveness of programmes. A paper by Walter Klyce and coauthors showed that pedicle screw plowing occurred in 4% of idiopathic scoliosis patients and was primarily in a cranial direction. It occurred more often in larger curves and in those with lower implant density. One-fourth of these experienced loss of correction, especially at the lowest instrumented vertebra, and plowing increased the revision risk by 16 fold.
The next SRS meetings with be IMAST in Athens, Greece (1–4 April, 2020) and the Annual Meeting in Phoenix, USA (9–12 September, 2020).
Paul Sponseller is a professor of orthopaedic surgery at the Johns Hopkins School of Medicine (Baltimore, USA), and serves as the chief of the Division of Paediatric Orthopaedics at the Johns Hopkins Children’s Centre.