Volume Navigation with Fusion of Real-Time Ultrasound and CT Images to Guide Posterolateral Transforaminal Puncture in Percutaneous Endoscopic Lumbar Discectomy.

Background: The use of percutaneous endoscopic lumbar discectomy (PELD) is increasing in the treatment of lumbar disc herniations (LDH). Nerve and vessel injury may happen during the establishment of the transforaminal working channel. Also, there is usually exposure to intraop radiation when the C-arm is used to help establish the location of the transforaminal working channel.

Objective: To evaluate the accuracy and safety of the volume navigation technique for guiding transforaminal puncture in cadaver and clinical patient treatment.

Study Design: Cadaver experiment and comparative clinical research.

Setting: Changhai Hospital, the Second Military Medical University.

Method: Volume navigation guided transforaminal puncture was performed in 15 cadavers. The registration error, time of overall puncture, ultrasound (US) observed distance between needle tip and target (DNT), and puncture error were recorded. Clinical research was performed in 63 patients who had undergone PELD. Comparative research was done between 2 groups: Those who had transforaminal puncture carried out under C-arm guidance (n = 30), and those patients whose transforaminal puncture was carried out under volume navigation guidance (n = 33). Puncture times and frequency of fluoroscopy were recorded. Both groups were evaluated with Oswestry Disability Index (ODI), and visual analog scale (VAS) before surgery at 1, 3, and 6 months, and 1 year post-surgery.

Results: In the cadaver experiment, mean registration error was 2.66 ± 1.10 mm; DNT 20.08 ± 1.32 mm; puncture error 2.91 ± 1.29 mm; overall time of puncture 22.10 ± 5.20 min. In the clinical patient research, puncture times and frequency of fluoroscopy were significantly lower in the volume navigation group compared with the C-arm group (P < 0.001). There were no significant differences between the 2 groups in ODI and VAS scores (P > 0.05) at different time points.

Limitations: The correlation between the registration errors and the puncture errors requires further analysis. Also, due to the relatively small number of cases studied, additional cases need to be collected to obtain reliable results.

Conclusion: The volume navigation technique can be used for PELD because it helps to guide percutaneous posterolateral transforaminal puncture accurately with reduced puncture times and intraop radiation.

Key Words: Lumbar disc herniation (LDH), ultrasound volume navigation (US VNav), percutaneous endoscopic lumbar discectomy (PELD), foramen, puncture.