Also, a better outcome?
Employing this approach, Agarwal, Aker and Ahmad, found that the wedging at the apex was substantially reduced.
It is well described in the literature that loss of correction in traditional SHILLA is linked to the inability of the apical fusion to halt progression of deformity as a child grows. With the APC approach, the ability to substantially reduce apical wedging provides a tool to mitigate such occurrences.
As Agarwal and colleagues explained to OTW, “The result of this study provides clinical evidence of reverse vertebral modulation at the apex of the curve in patients with scoliosis and kyphoscoliosis, when modifying the traditional SHILLA technique with APC.”
The researchers also compared this technique with traditional growth rods, which are commonly used in developing countries; in contrast developed countries have completely transitioned into magnetically controlled growth rods. A major problem with traditional growth rod technique is that it requires repeated invasive surgeries to distract the spine.
The researchers demonstrated equivalent clinical results between APC and growth rods, without the need for repeated surgeries with the latter, thus recommending it as a safer substitute to traditional growth rods.
A Closer Look at Methodology
The hospital’s institutional review board approved the 6-year study. The investigators enrolled 20 children who they’d diagnosed with scoliosis and kyphoscoliosis and were scheduled to undergo either index surgery or revision surgery. According to the study researchers, each patient’s imaging showed “clear evidence of vertebral wedging at the apex.” The investigators also included a subgroup of children with congenital disease. Finally, the researchers noted that the patients they’d enrolled presented with malformation, malsegmentation and unilateral bony bar.
The study authors acknowledged the limitations of their study, including the number of patients and the fact that the precise amounts of applied compression at the apex was not measured.
The researchers performed all of the pediatric spinal surgeries with an intraoperative neuromonitor and C-arm. In the modified SHILLA version of the study, the researchers used Medtronic’s SHILLA screws. When these screws were not available, they used rod to domino sliding.
The authors selected the most severely wedged vertebra, and inserted pedicle screws into the convex side of the vertebrae both above and below the noted wedged vertebra. They did not insert any screws on the concave side of the apex.
The researchers primarily used an extraperiosteal technique, with the exception of the convex side of the apical/wedged vertebrae. The authors placed screws at this site for compression and placed rods and domino subfascially to avoid prominence.
The researchers used computed tomography to measure the convex and concave heights of wedged vertebrae at the time of surgery and at follow up.
Finally, the investigators chose patient-specific control vertebra with similar physical dimensions to the wedged vertebra to record standard growth rates for the duration of follow up and the age of each patient. They did not apply compression forces at the convex end of the control vertebra.
The patients did not use post-operative casts or braces. The average duration of follow-up was 32 months; 8 months was the minimum.
