Selective Intraoperative Administration of Local Anesthesia in Breast Reconstruction

One in eight women will develop breast cancer in her lifetime, and many of these women
undergo mastectomy followed by breast reconstruction by insertion of a tissue expander below
the pectoralis major muscle. Women undergoing breast reconstruction have been shown to have
a significantly higher level of acute postoperative pain and postoperative narcotic
requirement compared to women who undergo mastectomy alone without reconstruction. In
addition to the inherently worthwhile end of providing patient comfort in the immediate
postoperative period, decreased narcotic use carries with it the potential benefit of
decreasing the incidence of other adverse effects such as nausea, vomiting, allergic
reaction, and respiratory depression.

Importantly, the intensity of pain in the immediate postoperative period has been implicated
as an important factor predisposing patients to the development of chronic postoperative
pain. Chronic pain following mastectomy is a significant and disabling problem, affecting up
to 49% of patients in some series. Though breast reconstruction has been shown not to be an
independent predictor of the development of chronic breast pain, improved control of acute
pain in the immediate postoperative period carries significant promise in decreasing the
incidence of this disabling condition for all breast cancer survivors treated with
mastectomy. In addition, improving management of acute postoperative pain can shorten
hospital stay, expedite return to daily normal activities and increase patient satisfaction.

A variety of other adjuncts for pain control have been attempted in studies of variable
methodological rigor, including injection of botulinum toxin into the pectoralis muscle,
indwelling pain catheters, paravertebral blocks under ultrasound guidance, or simple
irrigation of the general area of dissection during breast surgery with a solution
containing local anesthestic. While each of these adjuncts has demonstrated some success,
none has been widely adopted. Problems with these methods include cost, risk of adverse
events, as well as anatomically incomplete or non-selective application.

During mastectomy all breast tissue is removed, leaving the patient with denervated skin
flaps. For breast reconstruction, a tissue expander is placed in a subpectoral pocket
dissected between the pectoralis major and minor muscles. At the end of the procedure the
pectoralis major muscle is placed under variable degree of tension depending on the amount
of fluid placed inside the expander. This muscle stretch believed to be at least partially
responsible for postoperative pain. In addition cut nerve endings in the superficial fascia
likely contribute as well. The anatomy of nerves supplying the breast and involved muscles
are well-described in rigorous cadaver studies.

In this study we hypothesize that performing a block of the intercostal nerves responsible
for innervating the breast tissue and skin and the pectoral nerves innervating the
pectoralis major muscle should optimize immediate postoperative pain control in this patient
population. Of adjuncts described in the literature, paravertebral blocks are the most
anatomically targeted, but drawbacks include the need for a separate procedure
preoperatively while the patient is awake by an anesthesiologist with facility performing
these blocks as well as the risk of pneumothorax. Advantages of our proposed method include
lack of pain as the patient is asleep, easy and speed of application, a decreased risk of
pneumothorax as the injections are under direct visualization, as well as a decrease in cost
and improved efficiency as the only a single provider (i.e. the operative surgeon) is
required. Precedent for our technique has been described in the context of breast
augmentation and breast lift, with a favorable safety profile and providing adequate
analgesia to perform these procedures without the use of a general anesthetic.

Inclusion Criteria:

- Patients who undergo mastectomy surgery with immediate reconstruction involving
insertion of a tissue expander performed by the principal investigator beginning from
the time of study approval until study enrollment is complete.

Exclusion Criteria:

- Patients under the age of 18, or over the age of 79

- Allergy to local anesthetics or corticosteroids

- Patients with history of chronic pain or with chronic use of opioid analgesics

- Patients with history of lung disease or prior anterior thoracotomy or median
sternotomy