Regional Anesthesia for Breast Reconstruction

Anatomy and Physiology

Anatomy and landmarks will depend on the different types of blocks that can be made:

Paravertebral Block

First discovered by Hugo Sellheim from Leipzig in 1905 and described by Lawen (1911) and Kappis (1919), but did not have much success until the late 1970s, thanks to the efforts of Eason and Wyatt who reevaluated thoracic paravertebral block (TPVB) and showed its beneficial effect on reducing postoperative pain.[9]

The paravertebral space is delimited anterolaterally by the parietal pleura, posteriorly by the costotransverse ligament, medially by the vertebrae and intervertebral foramina, and inferior and superior by the ribs. In this space, we perceive the division of the vertebral root, which emerges from the intervertebral foramen to give dorsal and ventral branches. The sympathetic chain lies in the same plane, in front of the intercostal nerve, and communicates with it via the rami communicates.

Local anesthetic injection along the thoracic vertebra near where the spinal nerves emerge from the intervertebral foramen will cause unilateral, segmental, somatic, and sympathetic anesthesia, including the posterior ramus in multiple thoracic dermatomes.[10] This extension of the somatic and sympathetic blockade was evaluated by Cheema et al. (1995) using a thermographic imaging technique.[11] A contralateral distribution of the paravertebral block was reported by Karmakar et al. (2000) with a contrast agent.[12]

Intercostal Nerve Block

First described in the Die Lokalanastesie manual by Braun in 1907, today, it is used in thoracic and abdominal surgery to manage acute and chronic pain.

The thoracic nerves T1 to T12, after they emerge from the respective intervertebral foramina, give rise to the following rami:

1. The anterior communicates rami, which passes anteriorly to the sympathetic ganglion and chain. 
2. The posterior cutaneous rami, responsible for the innervation of the skin and muscles of the paravertebral region
3. The ventral ramus: gives rise to intercostal nerves.

Each intercostal nerve exists in a neurovascular bundle with an intercostal artery and vein; the nerve remains inferior to the two blood vessels—their paths in the thorax pass between the parietal pleura and the internal and external intercostal muscles. Near the midaxillary line, the nerves divide into a dorsal and ventral branch.

T1 and T2 support the innervation of the upper limbs and upper thorax, T3 to T6 cover the thorax, T7 to T11 supply the lower thorax and abdomen, and T12 the anterior gluteal region.[13]

The injection of local anesthetic into the subcostal groove spreads distally and proximally to block the intercostal nerves' ipsilateral sensory and motor fibers.

Erector Spinae Plane Block

First described by Forero m et al.[14] It concerns the paraspinal interfascial plane in which the infiltration applies between the erector muscle of the spine and the thoracic transverse processes.

The local anesthetic ensures the blocking of the dorsal and ventral rami of the thoracic and abdominal spinal nerves. This leads us to a multi-dermatomal sensory block of the anterior, posterior, and lateral thoracic and abdominal walls.[14] due to the cranial and caudal spread of the injected product.

Recent studies based on imagery highlight this diffusion of the injected local anesthetic, which passes through the connective tissues and towards the spinal nerve roots, thus allowing coverage of 3 to 4 cephalic and caudal dermatomes.[15][16]

Pectoralis Nerve Block

The nerves involved in pectoral nerve block (PECS) I and II are the pectoral nerve, intercostal nerve 3-6, intercostobrachial nerve, and long thoracic nerve.

The Pecs I block anesthetizes both the medial and lateral pectoral nerve. It focuses on the interfacial region between the pectoralis major muscle and the pectoralis minor muscle at the level of the third rib.

The PECS II, the anatomical region concerned, is located between the pectoralis major and the pectoralis minor as for a Pecs I block, followed by infiltration between the pectoralis minor and the serratus anterior, which will block the anterior skin branches of intercostal nerves 3 to 6, intercostobrachial nerves, and the long thoracic nerve.

Serratus Anterior Plane Blocks

First described by Blanco et al. in 2013, the anatomical region concerned is located between the latissimus dorsi and the anterior serratus muscle, on the mid-axillary line at the level of the fifth rib, thus exerting its analgesic effects on the lateral thoracic region.[17][18][19] This effect is achieved by blocking the nerves of the axillary fossa, which includes the intercostobrachial nerve, the cutaneous intercostal nerve (T3-T9), the long thoracic nerve, and the thoracodorsal nerve located in the compartment between the serratus anterior muscle and latissimus dorsi muscle, and between the posterior and midaxillary lines.[20]

Indications

According to current literature, two-thirds of women who have had breast cancer surgery develop chronic pain.[21]

Several recent studies suggest that regional anesthesia combined with general anesthesia is involved in controlling acute postoperative pain avoiding a transition to chronicity and reducing opioid consumption, which prevents side effects like nausea and vomiting, respiratory depression, and hallucinations in elderly patients, leading to early revalidation, and reduced patient length of stay.[22][7][23]

Regional anesthesia has been widely implemented nowadays by anesthesiologists in breast cancer clinics because of its beneficial effects on reducing the resurgence of cancers demonstrated by several retrospective studies.[24] Neshith Govil et al. even demonstrated that injecting lignocaine to block the pectoral nerves allows better postoperative analgesia compared to other patients without regional anesthesia and decreases the secretion of angiogenesis markers, contributing to tumor generalization.[24][25]

Therefore, regional anesthesia is best indicated in patients with a history of chronic neuropathy who present with high opioid consumption before surgery or in patients with significant comorbidity factors in whom reduction of general anesthetics may be beneficial for their cardiorespiratory function and cerebral function.

Contraindications

The contraindications for regional anesthesia include:

• Patient refusal
• Infection at the site of injection
• Allergy to local anesthetics
• Systemic anticoagulation (INR >1.4 or inadequate time since cessation of anticoagulant per ASRA guidelines)[26]

Equipment

The various locoregional anesthesia techniques for breast reconstruction surgery are currently performed under ultrasound to minimize the risks of nerve damage and pneumothorax for certain nerve blocks and require the following equipment:

• Ultrasound guidance with the high-frequency probe or low-frequency curvilinear probe, depending on the depth of the block and the patient's body[27]
• Sterile sleeve and gel
• One 23 to 25-gauge needle for skin infiltration
• 20 mL of local anesthetic
• Needle size: 80 mm B-bevel nerve block needle
• One pack of gauze 4-inch x 4-inch
• Chlorhexidine gluconate solution for skin asepsis
• Sterile gloves
• Marking pen

Personnel

Locoregional anesthesia must be performed by qualified anesthesia and resuscitation personnel capable of managing the complications. For some nerve blocks, sedation is recommended depending on the patient's stress level.

The assistance of a nurse trained in regional anesthesia is beneficial to assist the anesthesiologist with proper procedure performance and patient sedation management if necessary.[28]

Preparation

According to WHO recommendations and guidelines, a complete checklist assessment should be performed before performing a medical procedure on the patient. In addition, a review of the patient's morbidity and mortality should be performed before. This evaluation should include medical history, physical examination, airway assessment, and analysis of preoperative tests.[29]

The patient should be informed of the risks and benefits of regional anesthesia and the possible complications before obtaining informed consent.

The procedure should be performed in a clinic specializing in regional anesthesia. Patient monitoring is mandatory and should monitor pulse oximetry, electrocardiography, and blood pressure, as described in the American Society of Anesthesiologist's standards for basic anesthetic monitoring.

Technique or Treatment

Thoracic Paravertebral Block

The conventional technique relies on the loss of resistance described by Eason and Wyatt (1979) to locate the paravertebral space after penetration and passage of the needle through the superior costotransverse ligament to end in the space. However, this technique is less used by locoregional anesthesia centers because the importance of failure rates and complications such as the invasion of the parietal pleura that can lead to pneumothorax have led the authors to modify their technique and to use an ultrasound-guided approach to ensure the correct location of the space.[9]

In 2009, a study based on cadaveric imaging by Luyet et al. described a catheter placement in the paravertebral space under ultrasound guidance. Surgical disinfection should include the cervicothoracic para-vertebral areas up to the lower edge of the scapula. Protection of the ultrasound probe and cable with a sterile ultrasound probe cover is mandatory. Therefore, an initial ultrasound examination of T2 to T6 of the paravertebral region on the surgical site is performed. Transportable ultrasound equipment and a 50 mm 15-6 MHz linear probe are used.[30]

After identifying the spinous process T4 or T5 by decrementing from the prominent vertebra of C7, the ultrasound probe is positioned on the spinous process of T4; a lateral movement is then made to visualize the transverse process. An oblique movement of the probe allows visualizing the typical double layer of the internal intercostal membrane,  the transverse process, and the pleura.

After skin infiltration with 1% lidocaine (1 ml), the guidance of the needle out of the plane with the needle positioned 1 cm caudal from the ultrasound probe is performed. Once the needle tip is in position between the internal intercostal membrane and the pleura, a local anesthetic is administered 30 seconds after negative aspiration.

Erector Spinae Plane Block

After identifying the spinous process of the 5th thoracic vertebra (T5), the transverse process is traced laterally about 2.5 to 3 cm from the midline in a longitudinal position; it is identified as a hyperechoic curvilinear structure with acoustic shading below (a sign of the trident) we can also see the vertebral lamina (sawtooth pattern) and the spinous processes medially with the costochondral junction laterally. One can identify the famous three muscles, the trapezius, rhomboid major, and erector spinae deeper, which insert on the transverse process of T5. The parietal pleura moves according to the patient's breathing and is visible as a hyperechogenic line between the transverse processes.

After skin disinfection, an 8 cm 22-G needle is inserted in the craniocaudal direction and advanced through the trapezius, rhomboid major, and erector spinae to contact the transverse process. The action must be done delicately. Hydrodissection with an injection of 2 to 3 ml of normal saline is necessary to confirm the correct placement of the needle. An injection of 20 ml of the local anesthetic into the interfascial plane deep to the erector spinae and a linear pattern lifting the muscle is visible after this injection.

Serratus Plane Block

After skin disinfection around the mid-axillary line area, moving the probe laterally and distally allows viewing of the 4th and 5th ribs. Next, the probe can be rotated in the coronary plane and tilted posteriorly until the serratus anterior muscle and latissimus dorsi muscle are identified. After local infiltration, a local anesthetic is injected into the fascia between the serratus anterior muscle and latissimus dorsi muscle.

Pectoralis Nerve Block

The patient is placed in the supine position with the arm in abduction. The ultrasound probe (high frequency) is placed infraclavicular to the lateral third of the clavicle. It is then moved laterally to locate the axillary artery and the vein directly above the first rib. This allows us to identify the pectoralis major and pectoralis minor muscles. The pectoral branch of the thoracoacromial artery becomes visible on color Doppler at the level of the 2nd rib or sometimes pulsatile for good examiners. The needle is inserted under ultrasound control from the superomedial to the inferolateral direction between the pectoral muscles. The local anesthetic solution can then be injected (Pectoralis nerve block I). Then, the probe is moved towards the axilla to identify the serratus anterior muscle above the 2nd, 3rd, and 4th ribs, the lateral border of the pectoralis minor, and Gerdy's ligament. The needle is then reinserted into the fascial plane between the pectoralis minor muscle and the serratus anterior muscle; the local anesthetic is injected after a negative aspiration test (pectoralis nerve block II).

Intercostal Nerve Block

It blocks the intercostal nerves' ipsilateral sensory and motor fibers; local anesthetic solution injected into the subcostal groove spreads distally and proximally. In adults, the injection site is at the angle of the rib (6 to 8 cm from the spinous processes). In children, the block is performed at the axillary line level posterior to the angle of the rib.

Ultrasound guidance reduces the risk of intravascular injection and pneumothorax. The probe is placed in a sagittal plane 4 cm laterally to the spinous process; the practitioner then visualizes the costal shadow and the parietal pleura, which moves with the patient's breathing. The needle can then be inserted in or out of a transducer plane and advanced to the lower edge of the rib. An injection of local anesthetic is then performed.

Complications

The practice of locoregional anesthesia requires a thorough knowledge of the potential complications of each procedure.

Complications include, as with any act of regional anesthesia: infections related to sterilization errors, bleeding with the appearance of hematomas at the puncture site, nerve damage, and local anesthetic toxicity. History of coagulopathy or anticoagulation should be reported before any regional anesthesia procedure. Thanks to the existence and progress of ultrasound devices, ultrasound-guided techniques seem to have less risk of nerve or vascular damage.

A paravertebral and intercostal block should preferably be practiced in the awake patient because of the risk of pneumothorax and intraneural injection for the intercostal block.

For certain nerve blocks, dissemination of the local anesthetic is possible from the injection site far from its target, leading to serious complications.[31]

 Total spinal block with subarachnoid spread has been reported after intercostal block for thoracotomy. Lekhak and colleagues described a total spinal block after inserting a paravertebral catheter.[32] Naja. Z et al. report a higher probability of vascular puncture and pneumothorax in the paravertebral bilateral block than in the unilateral block.[33]

Other authors have cited inadvertent vascular puncture (6.8%), hypotension (4%), and epidural or intrathecal spread.[34][35]

Pulmonary hemorrhage has also been reported in patients who underwent thoracic surgery and paravertebral block.[36][37]

Finally, Burlacu et al. (2005) and Crawley S M also reported an ipsilateral Horner syndrome after unilateral paravertebral anesthesia for breast cancer surgery by diffusion to the ipsilateral stellate ganglion.[38][39]

 These complications should raise the awareness of the anesthesiologist and emphasize the importance of understanding anatomy before any regional anesthesia act or procedure.

Clinical Significance

Breast cancer surgery with breast reconstruction is a potentially long and stressful surgery that can lead to complications and nerve damage manifested by acute postoperative pain, including phantom breast pain, intercostobrachial neuralgia, or even neuropathic pain.[40]

In some breast clinic centers, chronic pain symptoms at the operative site and ipsilateral upper limb may persist for up to 1 year after breast surgery or longer.[41] Studies have reported a correlation between chronic pain and the extent of the invasiveness of surgical procedures: 49% for a mastectomy with reconstruction, 31% for a mastectomy, and 22% for breast reduction.[42]

The factors influencing this transition to chronicity are linked to the intensity of the acute postoperative pain, the type of operation performed with total lymph node dissection, the involvement of regional lymph nodes, and the per- and postoperative radiotherapy.

In the literature, several authors have demonstrated the impact and positive effect of locoregional anesthesia in breast surgery on the incidence of chronic pain, which decreases morbidity and, therefore, reduces the length of hospital stay due to a decrease in opioid needs.[43][44][45] Aside from the beneficial effects on pain, some authors (Exadaktylos AK et al.) study the impact of regional anesthesia techniques during breast surgery on long-term oncological results. Thus an association between women who received regional paravertebral anesthesia and a significant decrease in the recurrence rate was demonstrated.[46][47]

Postoperative morbidity after cancer surgery can delay oncological treatment, adversely affecting cancer recurrence.[48] Several studies have shown that regional anesthesia suppresses surgical stress response and reduces immunosuppression during the perioperative period because of reduced consumption of volatile anesthesia and opioids. It allows the immune system to eliminate residual cancer cells.[49][24][50]

Randomized controlled trials (Wang L et al.) have shown a significant reduction in NK and T cell activity in patients who received locoregional anesthesia combined with general anesthesia.[51] The effects of this regional anesthesia on tumor mediators are still poorly understood. Uncontrolled pain in animals is known to suppress NK cells and promote metastasis.[52]

Enhancing Healthcare Team Outcomes

Skills

In today's healthcare environment, breast reconstruction surgery must be performed in specialized breast clinics with multimodal pain management to reduce acute postoperative pain and its progression to chronicity. This also implies collaboration between inter-professional and multidisciplinary teams. The choice of the locoregional anesthesia technique in this surgery must take into account various factors, in particular, the opinion of the patient, the surgeon, and the preferences of the anesthesiologists who must be able to perform the nerve block without difficulty for patient safety it is advisable to follow specific guidelines and protocols to conduct adequate regional anesthesia procedures.

Strategy

It is most appropriate and ideal to maintain continuous closed-loop communication between all members of the perioperative care team regarding the need, technique, and potential management issues associated with the regional anesthetic utilized.

Ethics

It is necessary to obtain thorough and comprehensive informed consent from either the patient or, in the case of patients without the capacity to consent, from their designated and authorized decision maker before the placement of any regional anesthesia. It is most appropriate for all team members to feel empowered to state, to the team and/or the patient, any concerns that they might have regarding the process, as this ensures buy-in from all stakeholders as well as provide additional layers of review and insight into any problematic matters as soon as possible.

Responsibilities

All team members have a duty to communicate their concerns, responsibilities, and activities with all other team members both contemporaneously and as indicated throughout the perioperative period based on their professional discretion.

Interprofessional Communication

All team members should respect the free flow of information and concerns among team members without allowing or producing an environment of hostility.

Care Coordination

All team members should consider it their duty to neither disrupt the work done by other team members nor, through their actions or inactions, create additional issues or increase the workload for other team members. [Level 4]

Nursing, Allied Health, and Interprofessional Team Interventions

To perform locoregional anesthesia safely qualified nursing team for the operating room and postoperative recovery is required. The nurses should be trained in post-anesthesia care units (PACU) and monitoring recovery from anesthesia and the success of analgesia.

Nursing, Allied Health, and Interprofessional Team Monitoring

Nerve blocks must be performed in a center equipped with vital sign monitoring devices for optimal monitoring of vital parameters and management of complications related to the toxicity of local anesthetics and nerve block and access to anesthesiologists for vigilant identification and treatment if complications arise.