Postsurgical breast pain can be a complex problem, with a number of etiologies. This pain can cause great frustration for both the practitioner and the patient if a peripheral nerve compression or neuritis is not properly identified. In particular, breast pain can be anxiety provoking in the patient who has undergone a resection of breast cancer, creating a misleading concern for cancer recurrence. During the evaluation and initial management of postsurgical breast pain, the diagnosis of somatic pain from intercostal nerve entrapment is often overlooked until quite late. This diagnosis is relatively simple to make if the examiner is cognizant of it during the initial history and physical examination. Early diagnosis can save both patient suffering and the cost of unnecessary and sometimes invasive medical procedures.

Pain after breast surgery is typically of low intensity and decreases with time. It is relatively common and has been reported in up to 63% of all patients (1). A study of 282 patients found the highest incidence of postoperative breast pain to be in those women who had a mastectomy with implant reconstruction (2). Pain located at or near the surgical scar has been reported in 6% of patients (3). Postoperative breast pain has also been reported after sternotomy, internal mammary artery grafting, and thoracotomy (4,5,6). Most frequently, pain is rather well controlled with oral analgesics and decreased activity for 2 to 3 days. However, in the patient in whom severe, and frequently debilitating, pain persists beyond expected postoperative recovery period, a high suspicion for a peripheral nerve etiology must be considered. In a study performed by deVries et al., scarring following tissue healing could cause entrapment of local nerves, and transected nerve fibers could proliferate into a painful neuroma (1). Surgical treatment of postoperative breast pain after mastectomy or breast reduction that is attributed to an intercostal nerve lesion has been discussed in the literature (7,8).

The distribution of sensory innervation to the breast is derived from the anterior and lateral cutaneous branches of the second through sixth intercostal nerves. The lateral cutaneous branch of these nerves passes through the internal and external intercostal muscles, anterior to the serratus anterior, and run along the pectoralis fascia before turning into the parenchyma of the breast. The anterior cutaneous branches pierce the pectoralis major in the parasternal line (9). The nipple is typically innervated through the lateral cutaneous branch of the fourth intercostal nerve, but the third and fifth intercostals nerves can also contribute to its innervation (10).

Figure 81.1 demonstrates the intercostal nerve branches in relation to the breast and chest wall. It should be noted that the primary sensation to the nipple-areolar complex is through intercostal nerves 3 and 4, which emerge at the superior-lateral and lateral margin of the breast. As such, these nerves are in an anatomic position that is frequently dissected and potentially can be damaged during breast reduction and mastectomy procedures, especially if there are variations to normal nerve path.

The diagnosis of a postoperative nerve entrapment syndrome is relatively simple, provided the examiner entertains the possibility in the differential diagnosis. More serious pathology should always be ruled out as the specific patient presentation warrants. More infrequent pathologic syndromes such as neural tumors, which are usually asymptomatic, can present with pain (11). Symptoms suggestive of intercostal nerve entrapment include pain that is sharp and burning in character, often located near the scar of a previous operation (8,12). The pain is often constant or fluctuating and is sometimes worse with changing position (13). Usually, the pain can be duplicated with light pinching of the skin in the affected area (14). Similarly, patients can often localize a discrete area of maximum tenderness, and a Tinel’s sign might or might not be present (6). Pain can be segmental in distribution along the dermatome of one or possibly more involved nerve roots (8,14). Most frequently following breast reduction or mastectomy procedures, the intercostal nerves involved are the lateral row, branches 3 through 5. Less frequently the medial row or more-caudal lateral branches may be involved. Nerve conduction studies or electromyography can be obtained (15). Their yield in this anatomic location can be questionable; therefore we do not find electrodiagnostic studies reliable or useful. In addition to physical exam, the diagnosis can be confirmed with administration of a 1% lidocaine nerve block to the suspected intercostal nerve performed proximal to the site of pain (7,8,13). Pain might present early or late after an operation, with a report in the literature of a patient who began experiencing pain some 25 years postoperatively (16). The most common scenario is that it usually follows surgery and continues beyond the expected postoperative period, or starts within a few months later.