Utilizing pre-operative MR imaging and adapting optimal needle puncture approach to improve radiofrequency ablation fraction of thoracic dorsal root ganglia

This experimental study evaluates the location of thoracic dorsal root ganglions (DRGs) through magnetic resonance imaging (MRI) scans, and evaluates the radiofrequency ablation (RFA) fraction of different puncture approaches on distinct DRG locations. Eight normal adult corpse specimens were used as thoracic spine specimens. An MRI examination was performed on each specimen using the following MRI sequences: STIR T2WI, fs-FRFSE T2WI, and 3D FIESTA-c. Then thoracic spine specimens (n = 14) were divided into three groups for RFA: Group A, using a transforaminal approach irrespective of DRG location; Group B, using a transforaminal, trans-lateral-zygapophysial or translaminar approach according to the DRG location; and Group C using a combination of puncture approaches. The quality of visualization of thoracic DRGs on STIR T2WI, fs-FRFSE T2WI, and 3D FIESTA-c scans were 53.5% (77/144), 88.2% (127/144), and 93.1% (134/144), respectively. In group A, the RFA fractions of the extraforaminal DRGs (N = 29), intraforaminal DRGs (N = 12) and intraspinal DRGs (N = 7) via a transforaminal approach were 72.6 ± 18.9%, 54.2 ± 24.8% and 32.9 ± 28.1% respectively. In group B, RFA of extraforaminal DRGs via a transforaminal approach (N = 43) or a trans-lateral zygapophysial approach (N = 45) led to ablation fractions of 71.9 ± 15.2% and 72.0 ± 17.9%, respectively; RFA of intraforaminal DRGs via a transforaminal approach (N = 14) or a translaminar approach (N = 16) led to ablation fractions of 57.1 ± 18.0% and 52.5 ± 20.6%, respectively; RFA of intraspinal DRGs via a transforaminal approach (N = 12) or a translaminar approach (N = 14) led to ablation fractions of 34.8 ± 24.6% and 71.8 ± 16.0%, respectively. In group C, the combined approach led to an ablation fraction for extraforaminal DRGs (N = 69) of 82.5 ± 14.1%, for intraforaminal DRGs (N = 39) of 81.5 ± 11.8%, and for intraspinal DRGs (N = 36) of 80.8 ± 13.3%. MRI can accurately assess DRG location before RFA. Adopting different and combined puncturing approaches tailored to different DRG locations can significantly increase the DRG RFA fraction.

Full Endoscopic Technique for High-Grade Up-Migrated Lumbar Disk Herniation via a Translaminar Keyhole Approach: Preliminary Series and Technical Note

Background and Study Aims Technically and anatomically, accessing a high-grade migrated lumbar disk herniation (LDH) using traditional full endoscopic lumbar diskectomy (FELD) approaches (either transforaminal or interlaminar) is challenging. The objective of this study was to present an effective and safe surgical approach for high-grade up-migrated LDH by translaminar FELD. Patients and Methods Thirteen patients with soft high-grade up-migrated LDH treated with a translaminar FELD between May 2015 and July 2018 were reviewed in this study. Five of these patients had very high-grade up-migration. Clinical outcomes were assessed including preoperative and postoperative visual analog scale (VAS) for back and leg pain, Oswestry Disability Index (ODI), and MacNab criteria. Results Overall, 7 of the 13 patients had disk-fragment migration at L4–L5: three at L5–S1, two at L3–L4, and the remaining one at L2–L3. In all cases, the highly up-migrated LDH was removed successfully through the translaminar approach, as confirmed by postoperative magnetic resonance imaging. The improvements of VAS for back and leg pain were 4.5 ± 0.9 to 1.3 ± 1.3 and 7.1 ± 1.0 to 1.6 ± 0.7, respectively (both p < 0.05). The ODI decreased from preoperative 41.9 ± 6.0 to postoperative 13.0 ± 4.1 (p < 0.05). According to the MacNab criteria, the satisfaction rate was 92.3% (excellent or good outcomes). None of the patients experienced any perioperative complications or recurrence during the follow-up period. Conclusion Although full endoscopic technique via the translaminar keyhole route may not be used as a routine surgical approach, it could serve as a feasible alternative method for patients with highly up-migrated disk herniation.