Cellular and molecular mechanisms involved in the analgesic effects of botulinum neurotoxin: A literature review.

Botulinum neurotoxins (BoNTs), derived from Clostridium botulinum, have been employed to treat a range of central and peripheral neurological disease. Some studies indicate that BoNT may be beneficial for pain conditions as well. It has been hypothesized that BoNTs may exert their analgesic effects by preventing the release of pain-related neurotransmitters and neuroinflammatory agents from sensory nerve endings, suppressing glial activation, and inhibiting the transmission of pain-related receptors to the neuronal cell membrane. In addition, there is evidence to suggest that the central analgesic effects of BoNTs are mediated through their retrograde axonal transport. The purpose of this review is to summarize the experimental evidence of the analgesic functions of BoNTs and discuss the cellular and molecular mechanisms by which they can act on pain conditions. Most of the studies reviewed in this article were conducted using BoNT/A. The PubMed database was searched from 1995 to December 2022 to identify relevant literature.

EFFECT OF ULTRASOUND-GUIDED SUBSARTORIAL APPROACH FOR SAPHENOUS NERVE BLOCK IN CASES WITH SAPHENOUS NERVE ENTRAPMENT IN ADDUCTOR CANAL FOR CONTROLLING CHRONIC KNEE PAIN.

BACKGROUND: Saphenous nerve neuropathy is one of the causes of chronic pain of the knee. Blockade of saphenous nerve under sonographich guide has been used for controlling pain in recent years. The goal of this study was to evaluate the effect of saphenous nerve block for controlling pain in patients with chronic knee pain. METHOD: Thirty five patients with chronic knee pain referred to Amir Alam hospital during June 2012-June 2013 were enrolled in this study. Under sonographic approach, subsartorial blockade of saphenous nerve conducted and patients were followed up for 3 months after treatment. Demographic data, ASA (American Society of Anesthesiologists) category, weight, height, complications of intervention and pain scores were recorded. RESULTS: In 54%, the NRS was zero 30 minutes after intervention. In one patient (2.8%) all NRSs were 0 after intervention. We observed no sensory dysfunction in enrolled cases. CONCLUSION: The result of current study showed that ultrasound guided subsartorial approach is moderately effective in blockade of saphenous nerve in cases with saphenous nerve entrapment in adductor canal for controlling chronic knee pain.

Comparing Three Different Modified Sitting Positions for Ease of Spinal Needle Insertion in Patients Undergoing Spinal Anesthesia.

BACKGROUND: The most important point for performing a neuroaxial block in a sitting position is reducing lumbar lordosis, resulting in easier access to interspinous space and dura mater. There are a few studies comparing 2 different sitting positions including a traditional sitting position (TSP) versus forward bending or hamstring stretch position (HSP) as well as TSP versus squatting position (SP) for reversing the lumbar lordosis and improving access to intervertebral space for neuroaxial block. OBJECTIVES: We compared 3 different sitting positions including traditional sitting position vs. hamstring stretch position vs. squatting position and hypothesized that squatting position reverses the lumbar lordosis and reduces the number of spinal needle bone contacts more than TSP and HSP. METHODS: A total of Thirty hundred and sixty ASA class I or II patients aged 18 to 60 years were scheduled for elective surgeries under spinal anesthesia were randomized into 3 groups. Our primary endpoint was the number of spinal needle-bone contacts and our secondary endpoint was ease of needle insertion or space identification. RESULTS: Demographic data were statistically different between the study groups. There was no statistical difference between the study groups regarding the number of needle bone contacts and the ease of finding intervertebral space (P = 0.63, P = 0.56, respectively). CONCLUSIONS: There was no statistical difference between the TSP, HSP, and SP regarding the number of needle bone contacts and the ease of finding of intervertebral space. In this regard, each of these 3 positions can be used as an alternative sitting position for administration of spinal anesthesia.