A lumbar sympathetic ganglion block (LSB) is a therapeutic method for complex regional pain syndrome (CRPS) affecting the lower limbs. Recently, LSB with botulinum toxin type A and B was introduced as a novel method to achieve longer duration of analgesia. In this study, we compared the botulinum toxin type A (BTA) with botulinum toxin type B (BTB) in performing LSB on patients with CRPS. LSB was performed with either BTA or BTB on patients with CRPS in their lower extremities. The length of time taken for patients to return to the pre-LSB pain score and the adverse effect of LSB with BTA/BTB were investigated. The median length of time taken for the patients to return to the pre-LSB pain score was 15 days for the BTA group and 69 days for the BTB group (P = 0.002). Scores on a visual analogue scale decreased in the patients of both groups, and no significant adverse effects were experienced. In conclusion, the administration of either BTA or BTB for LSB is a safe method to prolong the sympathetic blocking effect in patients with CRPS. BTB is more effective than BTA to prolong the sympathetic blocking effect in CRPS patients.

For over a thousand years, various substances have been applied to the skin to treat pain. Some of these substances have active ingredients that we still use today. However, some have been discontinued due to their harmful effect, while others have been long forgotten. Recent concerns regarding the cardiovascular and renal risk from nonsteroidal anti-inflammatory drugs, and issues with opioids, have resulted in increasing demand and attention to non-systemic topical alternatives. There is increasing evidence of the efficacy and safety of topical agents in pain control. Topical analgesics are great alternatives for pain management and are an essential part of multimodal analgesia. This review aims to describe essential aspects of topical drugs that physicians should consider in their practice as part of multimodal analgesia. This review describes the mechanism of popular topical analgesics and also introduces the most recently released and experimental topical medications.

Grisuna Singh, Sejin Song, Eunjoo Choi, Pyung-Bok Lee, and Francis Sahngun Nahm. Korean J Pain 2020;33:201-7. https://doi.org/10.3344/kjp.2020.33.3.201

Balloon kyphoplasty is a minimally invasive procedure used in the treatment of vertebral compression fractures. Although cement leakage is a well-known complication of the procedure, delayed displacement of the injected bone cement material, occurring several weeks after kyphoplasty, is a rare occurrence. In this report, we describe a case of delayed dislodgement of the bone cement occurring 4 weeks after successful kyphoplasty for an osteoporotic compression fracture of L4. A balloon kyphoplasty was successfully performed for the clinical management of an osteoporotic compression fracture of the L4 vertebral body in a 74-year-old patient with Kummel disease. However, further progression of the collapse of L4 vertebra was identified on radiographic imaging obtained 4 weeks after the kyphoplasty. A cystic filling pattern of the bone cement was observed, rather than the expected matrix-like pattern, which contributed to the continued progression of the collapse of the vertebral body. As delayed displacement of bone cement can result in progression of an osteoporotic compression fracture of the vertebrae, we propose that sufficient penetration of bone cement into the microstructure of the trabecular bone of the vertebral body during kyphoplasty could reduce the risk of this phenomenon.

Purpose: Particulate steroids used in epidural steroid injections have been suspected as a cause of post-procedural embolic events. Some particulate steroids have been suspended only when the transforaminal approach is used for an epidural block of the spine. In contrast, non-particulate steroids are generally accepted for safety during epidural steroid injections. However, the safety of using a mixture of non-particulate steroids and local anesthetics is unknown. This study analyzed whether mixtures of commonly used non-particulate steroids and local anesthetics form crystals in solution. Methods: We mixed non-particulate steroids (betamethasone sodium phosphate, dexamethasone sodium phosphate, and dexamethasone palmitate) and local anesthetics (ropivacaine, levobupivacaine, bupivacaine, and lidocaine) at different ratios. We used fluorescence microscopy to observe whether crystals formed in mixed solutions; we also measured the pH of each steroid, local anesthetic, and the mixtures. Results: Ropivacaine or levobupivacaine and betamethasone sodium phosphate produced large crystals (> 50 μm). Ropivacaine or levobupivacaine and dexamethasone sodium phosphate produced small crystals (< 10 μm). Lidocaine and all non-particulate steroids produced no identifiable crystals; dexamethasone palmitate and all local anesthetics did not form significant particulates. Betamethasone sodium phosphate and dexamethasone sodium phosphate demonstrated basic pH, while all local anesthetics demonstrated acidic pH. Mixtures showed a wide pH range. Conclusion: Non-particulate steroids can form crystals upon combination with local anesthetics. Crystal formation may be caused by alkalinization of steroids. The mixing of ropivacaine or levobupivacaine and betamethasone sodium phosphate may require caution during an epidural steroid injection. Lidocaine or bupivacaine is recommended as a local anesthetic. Dexamethasone palmitate is a candidate for a mixture, but additional studies on its safety and effectiveness are needed.