Interventional approaches to pain management

Lidocaine-loaded reduced graphene oxide hydrogel for prolongation of effects of local anesthesia: In vitro and in vivo analyses

Lidocaine is widely used as a local anesthetic for alleviation of post-operative pain and for management of acute and chronic painful conditions. Although several approaches are currently used to prolong the duration of action, an effective strategy to achieve neural blockage for several hours remains to be identified. In this study, a lidocaine-loaded Pluronic® F68-reduced graphene oxide hydrogel was developed to achieve sustained release of lidocaine. Fourier transform infrared spectroscopy, X-ray diffraction, and Raman spectroscopy confirmed the synthesis of Pluronic® F68-reduced graphene oxide. Transmission electron microscopy showed wrinkled, flat nanosheets with micelles attached. The developed hydrogel showed desirable pH, viscosity, adhesiveness, hardness, and cohesiveness for topical application. The ex vivo release study demonstrated the ability of the Pluronic® F68-reduced graphene oxide hydrogel to prolong release up to 10 h, owing to the strong π-π interactions between the graphene oxide and the lidocaine. In comparison with a commercial lidocaine ointment, the developed graphene oxide hydrogel showed sustained anesthetic effect in the radiant heat tail flick test and sciatic nerve block model. Thus, this study demonstrates the potential of using Pluronic® F68-reduced graphene oxide nanocarriers to realize prolonged effects of local anesthesia for effective pain management.

[Single needle versus double needle celiac trunk neurolysis in abdominal malignancy pain management: a randomized controlled trial]

BACKGROUND

Computerized tomography-guided celiac plexus neurolysis has become almost a safe technique to alleviate abdominal malignancy pain. We compared the single needle technique with changing patients' position and the double needle technique using posterior anterocrural approach.

METHODS

In Double Needles Celiac Neurolysis Group (n = 17), we used two needles posterior anterocrural technique injecting 12.5 mL phenol 10% on each side in prone position. In Single Needle Celiac Neurolysis Group (n = 17), we used single needle posterior anterocrural approach. 25 mL of phenol 10% was injected from left side while patients were in left lateral position then turned to right side. The monitoring parameters were failure block rate and duration of patient positioning, technique time, Visual Analog Scale, complications (hypotension, diarrhea, vomiting, hemorrhage, neurological damage and infection) and rescue analgesia.

RESULTS

The failure block rate and duration of patient positioning significantly increased in double needles celiac neurolysis vs. single needle celiac neurolysis (30.8% vs. 0.13.8±1.2 vs. 8.9 ± 1; p = 0.046, p ≤ 0.001 respectively). Also, the technique time increased significantly in double needles celiac neurolysis than single needle celiac neurolysis (24.5 ± 5.1 vs. 15.4 ± 1.8; p ≤ 0.001). No significant differences existed as regards visual analogue scale: double needles celiac neurolysis = 2 (0-5), 2 (0-4), 3 (0-6), 3 (2-6) and single needle celiac neurolysis = 3 (0-5), 2 (0-5), 2 (0-4), 4 (2-6) after 1 day, 1 week, 1 and 3 months respectively. However, visual analogue scale in each group reduced significantly compared with basal values (p ≤ 0.001). There were no statistically significant differences as regards rescue analgesia and complications (p > 0.05).

CONCLUSION

Single needle celiac neurolysis with changing patients' position has less failure block rate, less procedure time, shorter duration of patient positioning than double needles celiac neurolysis in abdominal malignancy.

Single needle versus double needle celiac trunk neurolysis in abdominal malignancy pain management: a randomized controlled trial

Background

Methods

Results

Conclusion

Does sensory stimulation threshold affect lumbar facet radiofrequency denervation outcomes? A prospective clinical correlational study

BACKGROUND

Radiofrequency facet denervation is one of the most frequently performed procedures for chronic low back pain. Although sensory stimulation is generally used as a surrogate measure to denote sufficient proximity of the electrode to the nerve, no study has examined whether stimulation threshold influences outcome.

METHODS

We prospectively recorded data in 61 consecutive patients undergoing lumbar facet radiofrequency denervation who experienced significant pain relief after medial branch blocks. For each nerve lesioned, multiple attempts were made to maximize sensory stimulation threshold (SST). Mean SST was calculated on the basis of the lowest stimulation perceived at 0.1-V increments for each medial branch. A positive outcome was defined as a ≥50% reduction in back pain coupled with a positive satisfaction score lasting ≥3 months. The relationship between mean SST and denervation outcomes was evaluated via a receiver's operating characteristic (ROC) curve, and stratifying outcomes on the basis of various cutoff values.

RESULTS

No correlation was noted between mean SST and pain relief at rest (Pearson's r=-0.01, 95% confidence interval [CI]: -0.24 to 0.23, P=0.97), with activity (r=-0.17, 95% CI: -0.40 to 0.07, P=0.20), or a successful outcome. No optimal SST could be identified.

CONCLUSIONS

There is no significant relationship between mean SST during lumbar facet radiofrequency denervation and treatment outcome, which may be due to differences in general sensory perception. Because stimulation threshold was optimized for each patient, these data cannot be interpreted to suggest that sensory testing should not be performed, or that high sensory stimulation thresholds obtained on the first attempt should be deemed acceptable.