Enrique Monzó1, André P Boezaart2,3,4, Richard Shane Tubbs5,6,7,8,9, Margarita Sanromán-Junquera10, Olga C Nin4, Miguel Angel Reina11. 1. Department of Anesthesiology, Madrid-Montepríncipe University Hospital, Madrid, Spain. 2. The Alon P. Winnie Research Institute, Gainesville, Florida, USA. 3. The Alon P. Winnie Research Institute, Still Bay, South Africa. 4. Division of Acute and Perioperative Pain Medicine, Department of Anesthesiology and Department of Orthopedic Surgery, University of Florida College of Medicine, Gainesville, Florida, USA. 5. Department of Neurosurgery, Tulane Center for Clinical Neurosciences, Tulane University School of Medicine, New Orleans, Louisiana, USA. 6. Department of Anatomical Sciences, St. George's University, St. George's, West Indies. 7. Department of Structural and Cellular Biology, Tulane University School of Medicine, New Orleans, Louisiana, USA. 8. Department of Neurosurgery and Ochsner Neuroscience Institute, Ochsner Health System, New Orleans, Louisiana, USA. 9. Department of Neurology, Tulane University School of Medicine, New Orleans, Louisiana, USA. 10. Department of Signal Theory and Communications, Telematics, and Computing Systems, Rey Juan Carlos University, Madrid, Spain. 11. CEU San Pablo University School of Medicine and Department of Anesthesiology, Madrid-Montepríncipe University Hospital, Madrid, Spain.
Abstract
BACKGROUND AND OBJECTIVES: The ultrasound-guided proximal infraclavicular costoclavicular block (PICB) appears popular but its results are inconsistent. We sought an accurate demonstration of septae formed between the brachial plexus cords. METHODS: We performed in-plane, lateral-to-medial PICBs on 120 patients and recorded images. Once the most superficial lateral cord component was entered, a 0.4-0.6 mA current was applied to confirm needle placement; 5 ml of local anesthetic (LA) solution was then injected and its spread was observed and recorded. As the needle was advanced, the presence or absence of a hyperechoic linear structure was noted before the deeper compartment was reached, specifically looking for the possible displacement of such a septum. RESULTS: Upon initial scanning, a septum was observed in 67 of the 120 patients (46.2%). However, there was clear displacement of a linear septum between the lateral cord compartment and the medial and posterior cord compartments that prevented spread between the compartments in 94.16% of patients. Piercing the septum evoked motor responses from the medial or posterior cord. The same anatomical regions were studied microanatomically by analyzing cross-sections obtained with the same approach angle as the ultrasound probe. CONCLUSIONS: Intraplexus fascial septae that bundled the medial and posterior cords into one compartment and separated them from the lateral cord were demonstrated and confirmed microanatomically. This suggests the need for two separate injections (or two separate catheter placements for continuous peripheral nerve blockade) into the superficial and deep compartments to ensure LA spread around all three cords of the brachial plexus at this level.
BACKGROUND AND OBJECTIVES: The ultrasound-guided proximal infraclavicular costoclavicular block (PICB) appears popular but its results are inconsistent. We sought an accurate demonstration of septae formed between the brachial plexus cords. METHODS: We performed in-plane, lateral-to-medial PICBs on 120 patients and recorded images. Once the most superficial lateral cord component was entered, a 0.4-0.6 mA current was applied to confirm needle placement; 5 ml of local anesthetic (LA) solution was then injected and its spread was observed and recorded. As the needle was advanced, the presence or absence of a hyperechoic linear structure was noted before the deeper compartment was reached, specifically looking for the possible displacement of such a septum. RESULTS: Upon initial scanning, a septum was observed in 67 of the 120 patients (46.2%). However, there was clear displacement of a linear septum between the lateral cord compartment and the medial and posterior cord compartments that prevented spread between the compartments in 94.16% of patients. Piercing the septum evoked motor responses from the medial or posterior cord. The same anatomical regions were studied microanatomically by analyzing cross-sections obtained with the same approach angle as the ultrasound probe. CONCLUSIONS: Intraplexus fascial septae that bundled the medial and posterior cords into one compartment and separated them from the lateral cord were demonstrated and confirmed microanatomically. This suggests the need for two separate injections (or two separate catheter placements for continuous peripheral nerve blockade) into the superficial and deep compartments to ensure LA spread around all three cords of the brachial plexus at this level.