Study Design: Retrospective cohort study. Background: Percutaneous pedicle screws (PPS) have the advantage of being able to better preserve the paraspinal muscles when compared with a traditional open approach. However, the nature of changes in postoperative paraspinal muscle after damage by lumbar fusion surgery has remained largely unknown. It is clinically important to clarify and compare changes in paraspinal muscles after the various surgeries. Objective: (1) To determine postoperative changes of muscle density and cross-sectional area using computed tomography (CT), and (2) to compare paraspinal muscle changes after posterior lumbar interbody fusion (PLIF) with traditional open approaches and minimally invasive lateral lumbar interbody fusions (LLIF) with PPS. Methods: We included data from 39 consecutive female patients who underwent open PLIF and 23 consecutive patients who underwent single-staged treatment with LLIF followed by posterior PPS fixation at a single level (L4-5). All patients underwent preoperative, 6 months postoperative, and 1-year postoperative CT imaging. Measurements of the cross-sectional area (CSA) and muscle densities of paraspinal muscles were obtained using regions of interest defined by manual tracing. Results: We did not find any decrease of CSA in any paraspinal muscles. We did find a decrease of muscle density in the multifidus at 1 year after surgery in patients in the PILF group, but not in those in LLIF/PPS group. Conclusions: One year after surgery, a significant postoperative decrease of muscle density of the multifidi was observed only in patients who underwent open PLIF, but not in those who underwent LLIF/PPS.
The manuscript submitted does not contain information about medical device(s)/drug(s). There were no relevant financial activities outside the submitted work. We did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors for this research. The study was approved by our institutional review board (application No. 1183).
BACKGROUND
Upper cervical spine instability is one of the most serious orthopedic problems in patients with Down syndrome. Despite the recent advancement of instrumentation techniques, occipitocervical fusion remains technically challenging in the very young pediatric population with small and fragile osseous elements.
OBSERVATIONS
A 27-month-old boy with Down syndrome was urgently transported to the authors’ hospital because of difficulty in standing and sitting, weakness in the upper limbs, and respiratory distress. Radiographs showed os odontoideum, irreducible atlantoaxial dislocation, and substantial spinal cord compression. Emergency posterior occipitoaxial fixation was performed using O-arm navigation. Improvement in the motor paralysis of the upper left limb was observed from the early postoperative period, but revision surgery was needed 14 days after surgery because of surgical site infection. The patient showed modest but substantial neurological improvement 1 year after the surgery.
LESSONS
There are several clinical implications of the present case. It warns that Down syndrome in the very young pediatric population may lead to rapid progression of spinal cord injury and life crisis. This 27-month-old patient represents the youngest case of atlantoaxial instability in a patient with Down syndrome. O-arm navigation is useful for inserting screws into very thin pedicles.
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