The effect of erector spinae plane block on respiratory and analgesic outcomes in multiple rib fractures: a retrospective cohort study.

Regional anaesthesia is often helpful in improving respiratory function and analgesia following multiple rib fractures. The erector spinae plane block has become the technique of choice in our institution due to its relative simplicity and purported safety. The aim of this retrospective cohort study was to determine its effectiveness in improving respiratory and analgesic outcomes. We reviewed electronic medical records of patients with traumatic rib fractures admitted to a level-one trauma centre between January 2016 and July 2017, who also received erector spinae plane blocks. We analysed the following outcomes before and up to 72 h after erector spinae plane blockade: incentive spirometry volume; maximum numerical rating scale static pain scores; and 12-h opioid consumption. Pre- and post-block data were compared. We included 79 patients, 77% of whom received continuous erector spinae plane block for a mean (SD) of 3.7 (1.9) days. The majority (85%) had other associated injuries. Incentive spirometry volumes improved from 784 (694) to 1375 (667) ml (p < 0.01) during the first 24 h following erector spinae plane blockade. Pain scores were reduced from 7.7 (2.5) to 4.7 (3.2) in the first three hours (p < 0.01). Reductions in opioid consumption were observed but did not achieve statistical significance. These improvements were largely sustained for up to 72 h. Mean arterial blood pressure remained unchanged from baseline. In conclusion, erector spinae plane blocks were associated with improved inspiratory capacity and analgesic outcomes following rib fracture, without haemodynamic instability. We propose that it should be considered to be a viable alternative to other regional analgesic techniques when these are not feasible.

A radiologic and anatomic assessment of injectate spread following transmuscular quadratus lumborum block in cadavers.

We performed bilateral transmuscular quadratus lumborum blocks in six cadavers using iodinated contrast and methylene blue. Computed tomography imaging was performed in four cadavers and anatomical dissection was completed in five. This demonstrated spread to the lumbar paravertebral space in 63% of specimens, laterally to the transversus abdominis muscle in 50% and caudally to the anterior superior iliac spine in 63% of specimens. There was no radiographic evidence of spread to the thoracic paravertebral space. Anatomical dissection revealed dye staining of the upper branches of the lumbar plexus and the psoas major muscle in 70% of specimens. Further clinical studies are required to confirm if the quadratus lumborum block might be a suitable alternative to lumbar plexus block.

Perineural entrapment of an interscalene stimulating catheter.

A patient undergoing elective total shoulder arthroplasty had an Arrow Stimucath™ (Arrow International Reading, PA, USA) stimulating catheter inserted in the region of the interscalene brachial plexus using an ultrasound-guided in-plane approach. There was subsequent difficulty in removing the catheter and traction was associated with painful paraesthesia in the patient's thumb. Plain X-ray revealed a hook-shaped deformity of the tip and surgical exploration was required to remove the catheter, the tip of which appeared to be trapped within the sheath of the brachial plexus. We speculate that the mechanism for entrapment in this case was deformation of the catheter tip into a hook-like shape. The subsequent catheter-neural interaction prevented asymptomatic removal. We recommend that removal of peripheral nerve catheters be attempted only after resolution of sensory block so as to enable patients to report pain or paraesthesia. Imaging with ultrasound or X-rays may help ascertain catheter tip location and confirm whether deformity is present. We also recommend a low threshold for proceeding to surgical extraction, particularly if neurological symptoms are present.

The saphenous nerve and its relationship to the nerve to the vastus medialis in and around the adductor canal: an anatomical study.

BACKGROUND: Recently, ultrasound-guided saphenous nerve blocks within and distal to the adductor canal have shown success. However, a potential side effect is an unintentional block of branches of the nerve to the vastus medialis resulting in undesired motor weakness. METHODS: We dissected 40 embalmed cadaver thighs to determine the course and relation of the saphenous nerve to the nerve to the vastus medialis. Measurements were taken between various landmarks, and descriptive statistics were used to present the collected data. RESULTS: In 72.5% of specimens, the most distal visible branch of the nerve to the vastus medialis pierced the muscle proximal to the site where the saphenous nerve crosses the anterior surface of the superficial femoral artery to become medial to the vessel. CONCLUSION: Knowledge of this anatomy may help establish a safe region in preventing motor blockade when performing saphenous nerve blocks.