Depth of cervical plexus block and phrenic nerve blockade: a randomized trial

Background and objectivesCervical plexus blocks are commonly used to facilitate carotid endarterectomy (CEA) in the awake patient. These blocks can be divided into superficial, intermediate, and deep blocks by their relation to the fasciae of the neck. We hypothesized that the depth of block would have a significant impact on phrenic nerve blockade and consequently hemi-diaphragmatic motion.MethodsWe enrolled 45 patients in an observer blinded randomized controlled trial, scheduled for elective, awake CEA. Patients received either deep, intermediate, or superficial cervical plexus blocks, using 20 mL of 0.5% ropivacaine mixed with an MRI contrast agent. Before and after placement of the block, transabdominal ultrasound measurements of diaphragmatic movement were performed. Patients underwent MRI of the neck to evaluate spread of the injectate, as well as lung function measurements. The primary outcome was ipsilateral difference of hemi-diaphragmatic motion during forced inspiration between study groups.ResultsPostoperatively, forced inspiration movement of the ipsilateral diaphragm (4.34±1.06, 3.86±1.24, 2.04±1.20 (mean in cm±SD for superficial, intermediate and deep, respectively)) was statistically different between block groups (p<0.001). Differences were also seen during normal inspiration. Lung function, oxygen saturation, complication rates, and patient satisfaction did not differ. MRI studies indicated pronounced permeation across the superficial fascia, but nevertheless easily distinguishable spread of injectate within the targeted compartments.ConclusionsWe studied the characteristics and side effects of cervical plexus blocks by depth of injection. Diaphragmatic dysfunction was most pronounced in the deep cervical plexus block group.Trial registration numberEudraCT 2017-001300-30.

Using the BBraun BSmartTM Pressure Manometer to Prevent Unsafe Injection Pressures During Simulated Peripheral Nerve Blockade: A Pilot Study

Background: Peripheral nerve injury during regional anaesthesia may result from accidental intraneural placement of the needle, or forceful needle nerve contact. Intraneural injections are associated with increased resistance to injection, typically >15 psi. The BBraun BSmart™ is an inline mechanical manometer, offering a visual display of injection pressures. Objective: The primary objective of this study was to determine if using the BBraun BSmartTM manometer successfully prevents 90% of anaesthetists and anaesthetic assistants from injecting at pressures > 15 psi during simulated nerve block. Methods: This was a prospective observational study involving anaesthetists and anaesthetic assistants. Two 20 ml injections were performed by each participant, once when the BBraun BSmartTM manometer was obscured from view, and once with the manometer visible. A PendoTech PressureMATTMS recorded injection pressures. Results: 39 participants completed the study, with a total of 78 injections recorded. During the study, 32 peak pressures during the 78 procedures were recorded above the recommended upper limit of 15 psi, 41% of the total injections. The peak pressure rose above 15 psi in 24/39 (62%) injections when the BBraun Bsmart™ manometer was obscured, but only in 8/39 (21%) injections when the manometer was visible. Conclusion: The BBraun Bsmart™ manometer did not successfully prevent 90% of anaesthetists or anaesthetic assistants from injecting at unsafe pressures. However, using the BBraun BSmart™ did reduce the number of unsafe injection pressures generated by participants. When utilised in conjunction with PNS and ultrasound guidance, this may offer additional safety during peripheral nerve blockade.

Greater occipital nerve blockade using ultrasound guidance for the headache of spontaneous intracranial hypotension - A case report -

BackgroundSpontaneous intracranial hypotension occurs due to cerebrospinal fluid leakage from the spinal column, and orthostatic headache is the most common clinical presentation. Recent studies showed that bilateral greater occipital nerve blockade demonstrated clinical efficacy in relieving post-dural puncture headache after caesarean section. CaseA 40-year-old male who presented severe orthostatic headache was consulted to our pain clinic from neurology department. He initially felt a dull nature pain over the whole occipital area which then spread over the frontal and parietal areas. His headache was combined with nausea and vomiting. An epidural blood patch was delayed until final cisternography, and bilateral greater occipital nerve blockade using ultrasound guidance was performed instead. After the blockade, the previously existing headache around the occipital and parietal areas disappeared completely, but mild headache persisted around the frontal area.ConclusionsGreater occipital nerve blockade could be a good therapeutic alternative to improve headache resulting from spontaneous intracranial hypotension.

Addition of lesser occipital nerve blockade to greater occipital nerve blockade in patients with chronic migraine

Objectives: The aim of this study was to compare greater occipital nerve blockade (GONB) alone and GONB combined with lesser occipital nerve blockade (LONB) in chronic migraine patients. Methods: Patients were randomly divided into two groups: Group A consisted of 22 patients who received only GONB; while Group B consisted of 20 patients who underwent GONB and LONB. The demographics and clinical characteristics of the patients were evaluated. The injections were given unilaterally and to the side where the subjects experienced greater pain. GONB with or without LONB was performed on each patient once a week for 4 weeks and then two more times a month apart; 6 times in total. The number of headache days, severity of attacks and duration of headache episodes was recorded from headache diaries before treatment and the on the first, second and third month following the start of treatment. Treatment efficiencies were evaluated within and between the groups. Results: The duration of pretreatment headaches was significantly longer in Group B (p=0.032). There were no differences between the groups in terms of other demographic and clinical characteristics. When the treatments applied in group A and group B were evaluated separately compared to the control group, there was a statistically significant decrease in the number of headache days, VAS scores and headache duration (p <0.05). When the results of treatment between groups were compared, there was no difference in terms of the number of headache days and VAS scores. Although the duration of headache was longer in the pretreatment period in group B, this difference disappeared on posttreatment follow-up (p>0.05). Conclusions: This study suggests that there is no difference in the number of headache days or headache intensity between GONB alone or in combination with LONB in chronic migraine patients. GONB combined with LONB in patients may be more effective than GONB alone when headaches of longer duration are present.

Use of Liposomal Bupivacaine in Pediatric Peripheral Nerve Blocks after Traumatic Amputation

Liposomal bupivacaine has been explored for indications in regional anesthesia, but little has been reported about its use in pediatric patients. In March 2021, the FDA approved an indication for liposomal bupivacaine as an infiltrated local anesthetic in children older than the age of six. Despite this recently expanded indication, the literature lacks reports of use for peripheral nerve blockade in children. We describe a case where liposomal bupivacaine was used for femoral and sciatic nerve blocks in a 5-year-old child with traumatic amputation of his lower leg. Pain control was excellent, with no pain or opioid use reported during the first 62 hours. After the regional anesthesia subsided, the patient required in total 4 oral doses of oxycodone 0.1 mg/kg prior to discharge. The patient did not develop chronic pain or phantom limb syndrome. While liposomal bupivacaine is not currently FDA-approved for peripheral nerve blockade in children, this case highlights a potentially effective use of this drug and possible area for further investigation.