The Value and Application of Personalized Needle Modification in Percutaneous Infrazygomatic Radiofrequency in Isolated Maxillary Nerve Pain through the Foramen Rotundum

Background: Percutaneous infrazygomatic radiofrequency (PIR) is a common approach used toblock isolated maxillary nerve (V2) pain through the foramen rotundum (FR) in patients with trigeminalneuralgia (TN). Nevertheless, when using this method, there is a risk of accidental penetration of thesuperior orbital fissure (SOF) and the optic canal (OC) that may result in the injury of the vessels andnerves in that area, and in some severe cases may lead to blindness. According to the blocking ofthe external orifice of the FR and whether a curved needle was used, combined angle deviation fromthe path of percutaneous infrazygomatic approach, the FR to the SOF or the OC in the treatmentof V2 pain, in which no research has reported the angle, we analyzed the value and application ofpersonalized needle modification in PIR in isolated maxillary nerve pain through the FR.Objectives: The following study examined the relationship between the FR and the SOF, and analyzedthe clinical significance of personalized needle modification in computed tomography (CT)-guided PIRablation of the maxillary nerve through the FR in patients with TN.Study Design: Randomized, review, clinical research study.Setting: Department of Anesthesiology and Pain Medical Center, Jiaxing, China.Methods: Three-dimensional reconstruction was performed in 88 patients and 136 patients withPIR ablation in isolated maxillary nerve pain through the FR. According to the blocking of the externalorifice of the FR and whether a curved needle was used, patients were divided into 4 groups: curvedneedle blocking group (CB), straight-needle blocking group (SB), straight needle no-blocking group(SN), and curved-needle no-blocking group (CN).Results: The results obtained revealed minimum H (shortest diameter of the FR) = 1.0 mm andminimum L (length of the FR tubes) = 3.7 mm. The distance between the external orifice of the FR andthe SOF (FS) was 5.16 ± 1.33 mm. The angle A (between the radiofrequency needle and the sagittalplane) was 39 ± 3.95°; the angle between the canthomeatal line and the CT scan line (ACT) was 58.99± 6.23°; the puncture depth (LS) was 63.99 ± 4.24 mm; the deviation angle of the misplacement intothe SOF (SAF) was 2.96 ± 0.71°; the deviation angle of the misplacement into the OC (OAF) was 4.95± 0.73°. In addition, the postoperative Numeric Rating Scale scores in the CB group were significantlylower compared with the SB group, whereas the probability of entering the SOF in the CB group wassignificantly lower compared with the SB group. The total number of punctures in the SN group wasless than that in the CN group.Limitations: Additional clinical data should be collected to preserve the results in future work.Conclusions: The distance between the FR and the SOF or the OC was only few millimeters, andslight angle error could lead to the SOF and the OC. For patients with blockage in the path, thetreatment of radiofrequency with personalized needle modification could improve the curative effectand reduce the risk of accidental SOF penetration.Key words: Trigeminal neuralgia, foramen rotundum, superior orbital fissure, radiofrequency,personalized needle modification