FP6.4 Exploration of the subgluteal space during endoscopic sciatic nerve release guided by indocyanine green fluorescence

The subgluteal space (SS) includes several vascular-nerve structures (sciatic nerve (SN), posterior femoral cutaneous nerve (PFCN), the superior and inferior gluteal artery, and others), so there is a high risk of iatrogenic injury. Indocyanine green (ICG) fluorescence-guided surgery gained popularity to identify complex structures intraoperatively, but its use is not frequent in endoscopic orthopedic procedures. In this case report, we evaluated the usefulness of ICG during endoscopic SN release.

We reported the findings in two ICG-fluorescence-guided releases in two patients aged 65 (Case 1) and 68 years (Case 2), who were diagnosed with deep gluteal syndrome due to SN entrapment after physical examination and block injection. Access to the SS, was through the anterolateral, posterior, and accessory posterior portals. ICG was administered before and after SN release intravenously using a bolus dose of 0.2 mg/kg, with dilution of the 25mg/vial in 10 ml of distilled water. Prior to release and under near-infrared light, 3:15 (Case 1) and 2:50 (Case 2) minutes after administration of ICG, we observed the fluorescent images in the PFCN.

Additionally, in case 2, the inferior gluteal artery and a part of the SN were visualized after 4 minutes of administration of ICG. After SN release, luminescence began 30 seconds after ICG administration in both cases, allowing visualization of the PFCN, inferior gluteal artery and SN. In conclusion, ICG allows the correct identification of the main vascular-nerve structures within the SS, as well as objectively verifying the restoration of blood flow after SN release.

The inferior gluteal artery, located below the SN, showed a higher intensity compared to the luminance of the SN and PFCN.