Koyyalamudi, Veerandra

Background and objectives Studies show variable spread with thoracic erector spinae plane (ESP) injections. Injection sites vary from lateral end of the transverse process (TP) to 3 cm from the spinous process, with many not describing the precise site of injection. This human cadaveric study examined dye spread of ultrasound-guided thoracic ESP block at two needle locations. Methods Ultrasound-guided ESP blocks were performed on unembalmed cadavers. Methylene blue (20 mL, 0.1%) was injected in the ESP at the medial TP at level T5 (medial transverse process injection (MED), n=7) and the lateral end of the TP between T4 and T5 (injection between transverse processes (BTWN), n=7). The back muscles were dissected, and the cephalocaudal and medial-lateral dye spread documented. Results Dye spread cephalocaudally from C4-T12 in the MED group and C5-T11 in the BTWN group, and laterally to the iliocostalis muscle in five MED injections and all BTWN injections. One MED injection reached serratus anterior. Dorsal rami were dyed in five MED and all BTWN injections. Dye spread to the dorsal root ganglion and dorsal root in most injections, though more extensively in the BTWN group. The ventral root was dyed in 4 MED and 6 BTWN injections. Epidural spread in BTWN injections ranged from 3 to 12 levels (median: 5 levels), with contralateral spread in two cases and intrathecal spread in five injections. Epidural spread in MED injections was less extensive (median (range): 1 (0–3) levels); two MED injections did not enter the epidural space. Conclusion An ESP injection administered between TPs exhibits more extensive spread than a medial TP injection in a human cadaveric model.

Psychotropic drugs are used in the treatment of psychiatric and non-psychiatric conditions. Many patients who are on psychotropic medications may present for procedures requiring anesthesia. Psychotropic medications can have dangerous interactions with drugs commonly used in anesthesia, some of which can be life-threatening. In this review, we describe the current anesthetic considerations for patients on psychotropic drug therapies, including antidepressants, antipsychotics, mood stabilizers, anxiolytics, and stimulants. The pharmacology, side effects, and potential drug interactions of the commonly prescribed psychotropic drug therapies with anesthetic agents are described. Further, we highlight the current recommendations regarding the cessation and continuation of these medications during the perioperative period.

Background and objectives The costoclavicular brachial plexus block is performed deep and posterior to the midpoint of the clavicle. There are limited data evaluating the spread of the costoclavicular brachial plexus block. We performed a cadaveric study to evaluate the spread of injectate after a costoclavicular brachial plexus block. Methods Five ultrasound-guided costoclavicular block injections were performed with 20 mL of 0.1% methylene blue. The brachial plexus and its branches were dissected from the level of C4 to the lower axilla. The extent of dye spread was recorded including spread to the phrenic nerve, suprascapular nerve, roots, trunks, divisions, cords and terminal branches of the brachial plexus. Results The dye extended cephalad to the level of the cricoid cartilage in two of the five injections; three injections had dye extending 0.75 cm, 1.5 cm and 2 cm caudad to the level of the cricoid cartilage, respectively. The C7, C8 and T1 nerve roots were stained in all injections. The dye did not extend cephalad to the C5 and C6 nerve roots. All trunks, cords and divisions of the brachial plexus were stained, as was the suprascapular nerve. There was no spread of dye to the phrenic nerve in any of the specimens. Conclusions This cadaveric study demonstrates that ultrasound-guided injection in the costoclavicular space spreads cephalad to the brachial plexus in the supraclavicular space, consistently reaching the suprascapular nerve and all trunks and cords of the brachial plexus, while sparing the phrenic nerve.

Background and objectives The erector spinae plane (ESP) block is a relatively new interfascial block technique. Previous cadaveric studies have shown extensive cephalocaudal spread with a single ESP injection at the thoracic level. However, little data exist for lumbar ESP block. The objective of this study was to examine the anatomical spread of dye following an ultrasound-guided lumbar ESP block in a human cadaveric model. Methods An ultrasound-guided ESP block was performed in unembalmed human cadavers using an in-plane approach with a curvilinear transducer oriented longitudinally. 20 mL of 0.166% methylene blue was injected into the plane between the distal end of the L4 transverse process and erector spinae muscle bilaterally in four specimens and unilaterally in one specimen (nine ESP blocks in total). The superficial and deep back muscles were dissected, and the extent of dye spread was documented in both cephalocaudal and medial–lateral directions. Results There was cephalocaudal spread from L3 to L5 in all specimens with extension to L2 in four specimens. Medial–lateral spread was documented from the multifidus muscle to the lateral edge of the thoracolumbar fascia. There was extensive dye in and around the erector spinae musculature and spread to the dorsal rami in all specimens. There was no dye spread anteriorly into the dorsal root ganglion, ventral rami, or paravertebral space. Conclusions A lumbar ESP injection has limited craniocaudal spread compared with injection in the thoracic region. It has consistent spread to dorsal rami, but no anterior spread to ventral rami or paravertebral space.