The pectoral plane nerve block—PECS II is simply a PEC I block with additional injection of local anesthetic between the pectoralis major muscle and the serratus anterior muscle. This allows for local anesthetic to enter to fascial compartments and block not only the medial and lateral pectoral nerves but also the lateral branches of the upper intercostal nerves and occasionally the long thoracic nerve. Pectoral plane nerve block— PECS II is utilized as an alternative to paravertebral nerve block and thoracic epidural block to provide surgical anesthesia for surgeries that require a larger field of anesthesia than that obtained by the PECS I block alone (Fig. 90.1). Such surgeries include major procedures involving the pectoralis major muscle, mastectomy, breast reconstruction, subpectoral implants, surgeries involving the axilla including AV fistula formations, transapical transcatheter aortic valve implantations, wide excisions of the breast, and sentinel node biopsy (Fig. 90.2). This technique has great clinical utility in both children and adults when managing acute postoperative and posttrauma pain in the above mentioned areas. PECS II block can also be used in combination with paravertebral block following mastectomy and/or axillary surgery to facilitate physical therapy to maintain upper extremity function.

The anatomic basis for the PECS II, PECS III, and serratus anterior plane blocks is the fact that the fascia at the pectoral level creates potential compartments that can contain local anesthetics when injected within the facial compartments. Because the nerves contained within these fascial compartments traverse these fascial compartments, they are amenable neural blockade at various points along their paths. Since these fascial compartments can potentially prevent the spread of local anesthetic to block other nerves, repositioning of the needle tip into adjacent fascial compartments may be required in order to
provide complete anesthesia and analgesia to the regions, especially to the axilla and lateral breast. The pectoral plane nerve block—PECS II is simply a PEC I block with additional injection of local anesthetic between the deep fascia or the pectoralis minor muscle and the superficial serratus anterior muscle to block the lateral branches of the T2-T4 intercostal nerves and occasionally the long thoracic nerve (Fig. 90.3).

To perform ultrasound-guided pectoral plane nerve block— PECS II, place the patient in the supine position with the arms resting comfortably by the patient’s side (Fig. 90.4). A total of 20 mL of local anesthetic is drawn up in a 20-mL sterile syringe. If the painful condition being treated is thought
to have an inflammatory component, 40 to 80 mg of depot steroid is added to the local anesthetic. The PECS I portion of the PECS II block is performed by identifying the middle of the clavicle and then placing a linear high-frequency ultrasound transducer in the transverse plane just below the previously identified midpoint of the clavicle with the inferior portion of the transducer pointed inferomedially toward the patient’s axilla (Fig. 90.5). Under continuous ultrasound imaging, the transducer is slowly moved inferolaterally to identify the pectoralis major and pectoralis minor muscles as well as the thoracoacromial vessels that lie in the plane between the two muscles (Fig. 90.6). Color Doppler may help identify the thoracoacromial vessels as will slight lateral rotation of the inferior portion of the transducer (Fig. 90.7). The bright sunset line of the pleura should also be identified to allow the operator to avoid placing the needle too deeply (see Fig. 90.7).