Perioperative shear wave elastography for the evaluation of spinal cord release in pediatric dysraphism: first experience in 21 patients

Abstract

OBJECTIVE Shear wave elastography (SWE) is a recent method for evaluating soft tissue stiffness. Its application to the spinal cord is limited by the ultrasound bone barrier. Spinal dysraphism can cause neurological symptoms impairing bladder, bowel, and lower limb function due to a mechanical stress known as tethered cord syndrome. Detethering of the spinal cord is a part of surgical treatment. This study aimed to assess the feasibility of intraoperative elastography to guide surgery in patients with spinal dysraphism involving traction of the spinal cord. METHODS This single-center retrospective study included all patients who underwent surgery for spinal dysraphism between November 2023 and July 2024. SWE was performed under general anesthesia with the patient in the prone position before and after spinal cord detethering. All SWE measurements were performed using the Aixplorer system. Demographic, clinical, and radiological data (age at surgery, neurological status, and MRI findings) were collected. RESULTS Twenty-one patients with a mean $\pm$ SD (range) age of 3.7 $\pm$ 5.3 (0--17.5) years were included. Etiologies included open saccular dysraphism (n = 3), spinal cord conus lipoma (n = 6), limited dorsal myeloschisis (n = 3), and fibrolipomatous filum (n = 9). In 85% of patients, at least 1 clip was of sufficient quality for analysis both before and after release. The mean $\pm$ SD (range) spinal cord stiffness at the beginning of surgery was 25.2 $\pm$ 9.2 (12.3--39.1) kPa and 11.2 $\pm$ 3.8 (6.2--16.5) kPa at the end of release, with a significant stiffness decrease (p = 0.018). No complications attributable to SWE were observed. CONCLUSIONS SWE of the spinal cord in patients with spinal dysraphism is a safe and feasible imaging method. This technique may assist in assessing the adequacy of untethering during surgery. However, no established normative SWE values for the pediatric spinal cord currently exist. Until it does, the intraoperative interpretability and clinical utility of this technique remain limited.