A comparison of analgesic efficacy and safety of clonidine and methylprednisolone as additives to 0.25% ropivacaine in stellate ganglion block for the treatment of complex regional pain syndrome: a prospective randomised single blind study

Background

The role of the sympathetic nervous system appears to be central in causing pain in complex regional pain syndrome (CRPS). The stellate ganglion block (SGB) using additives with local anesthetics is an established treatment modality. However, literature is sparse in support of selective benefits of different additives for SGB. Hence, the authors aimed to compare the efficacy and safety of clonidine with methylprednisolone as additives to ropivacaine in the SGB for treatment of CRPS.

Methods

A prospective randomized single blinded study (the investigator blinded to the study groups) was conducted among patients with CRPS-I of the upper limb, aged 18-70 years with American Society of Anaesthesiologists physical status I-III. Clonidine (15 μg) and methylprednisolone (40 mg) were compared as additives to 0.25% ropivacaine (5 mL) for SGB. After medical treatment for two weeks, patients in each of the two groups were given seven ultrasound guided SGBs on alternate days.

Results

There was no significant difference between the two groups with respect to visual analogue scale score, edema, or overall patient satisfaction. After 1.5 months follow-up, however, the group that received methylprednisolone had better improvement in range of motion. No significant side effects were seen with either drug.

Conclusions

The use of additives, both methylprednisolone and clonidine, is safe and effective for the SGB in CRPS. The significantly better improvement in joint mobility with methylprednisolone suggests that it should be considered promising as an additive to local anaesthetics when joint mobility is the concern.

Pharmacological and non-pharmacological strategies for preventing postherpetic neuralgia: a systematic review and network meta-analysis

Background

Postherpetic neuralgia (PHN) is a refractory complication of herpes zoster (HZ). To prevent PHN, various strategies have been aggressively adopted. However, the efficacy of these strategies remains controversial. Therefore, we aimed to estimate the relative efficacy of various strategies used in clinical practice for preventing PHN using a network meta-analysis (NMA).

Methods

We performed a systematic and comprehensive search to identify all randomized controlled trials. The primary outcome was the incidence of PHN at 3 months after acute HZ. We performed both frequentist and Bayesian NMA and used the surface under the cumulative ranking curve (SUCRA) values to rank the interventions evaluated.

Results

In total, 39 studies were included in the systematic review and NMA. According to the SUCRA value, the incidence of PHN was lower in the order of continuous epidural block with local anesthetics and steroids (EPI-LSE), antiviral agents with subcutaneous injection of local anesthetics and steroids (AV + sLS), antiviral agents with intracutaenous injection of local anesthetics and steroids (AV + iLS) at 3 months after acute HZ. EPI-LSE, AV + sLS and AV + iLS were also effective in preventing PHN at 1 month after acute HZ. And paravertebral block combined with antiviral and antiepileptic agents was effective in preventing PHN at 1, 3, and 6 months.

Conclusions

The continuous epidural block with local anesthetics and steroid, antiviral agents with intracutaneous or subcutaneous injection of local anesthetics and a steroid, and paravertebral block combined with antiviral and antiepileptic agents are effective in preventing PHN.

Effects of Linearly Polarized Near-Infrared Irradiation Near the Stellate Ganglion Region on Pain and Heart Rate Variability in Patients with Neuropathic Pain

Background

Neuropathic pain associated with sympathetic overactivity can be effectively relieved by light irradiating the region near stellate ganglion (SGI), applied as an alternative to a conventional sympathetic blockade. The clinical effect of SGI on heart rate variability (HRV) and its association with pain outcomes require investigation.

Objective

This study attempted to identify the effects of SGI on pain outcomes and HRV indices and to determine the association between pain and HRV outcomes.

Design

A prospective double-blind, randomized study.

Setting

An outpatient pain medicine clinic.

Subjects and Methods

A total of 44 patients were enrolled and randomized into the experimental group ( n = 22) and control group ( n = 22). The experimental group received 12 sessions (twice weekly) of standard SGI, whereas the control group received the same protocol with sham irradiation. Pain and HRV were measured before and after each irradiation session. All outcome measures used in the first- and second-half treatment courses were analyzed.

Results

Pain and HRV outcome measures of the experimental group significantly improved after SGI when compared with the control group in both courses. Considering time and frequency domains, the changes in HRV in the second-half treatment course exceeded those in the first-half treatment course. Pain was significantly associated with postirradiated HRV indices ( P < 0.001).

Conclusions

Twelve sessions of SGI exerted time-dependent positive effects on pain and sympathovagal imbalance. HRV outcomes, including time and frequency domains, were an independent indicator of the clinical efficiency of SGI for treating pain in patients with neuropathic pain.

Transient neuronal injury followed by intravascular injection during an ultrasound guided stellate ganglion block

Ultrasound guidance for pain interventions is becoming increasing recognized as a useful imaging tool. One of the common interventions where it is gaining wider acceptance is during the performance of a stellate ganglion block. The following is a unique report where intravascular and neuronal injury occurred during the performance of an ultrasound guided stellate ganglion block followed by dysphagia. 41 year old male, with a diagnosis of complex regional pain syndrome, was referred to our clinic for further management. He underwent a diagnostic ultrasound guided stellate ganglion block after having tried conservative therapies. The stellate ganglion block provided him with complete pain relief for over five weeks. During a subsequent therapeutic stellate ganglion block, performed by an experienced pain medicine fellow with more than 50 ultrasound guided proceduresclinician, the patient developed a transient injury to the brachial plexus upon needle entry. Subsequent redirection and injection of an ml of injectate resulted in an intravascular injection producing tinnitus. After the tinnitus decreased, he underwent another stellate block using an out of plane approach without any further complications. Two days later, he reported chest and throat discomfort which resolved over the next few days possibly due to a retropharyngeal hematoma. He declined further interventions and was subsequently managed with 3 tablets of oxycodone a day. This report highlights the importance of vigilance and meticulous planning during the performance of ultrasound guided pain interventions.