23.2 Poland syndrome
Poland syndrome is a unilateral congenital chest deformity characterized by the absence of the sternal portion of the pectoralis major muscle. The morphological consequence of the missing muscle is that the anterior axillary fold is absent. The incidence of this anomaly ranges from 1 in 10 000 to 1 in 100 000 births. In females the diagnosis is often made only after breast development and patients are often referred to specialists because of breast asymmetry. Ipsilateral breast anomalies range from mild hypoplasia to total agenesia. Breast tissues are often fibrotic since the missing pectoralis major muscle is replaced by fibrotic bands or by a compact fibrous layer. In males, Poland syndrome is often misdiagnosed as a “chest asymmetry” and it is often recognized only after full development. The absence of the sternal component of the pectoralis major and breast anomalies can be associated with one or more of the following malformations:
Sir Alfred Poland (1822–1872) was a 19th century British surgeon best known for his description of a congenital deformity described as an underdevelopment or absence of the pectoralis major muscle on one side of the body as well as syndactyly on the ipsilateral hand.
Poland described the condition in 1841, in a paper entitled “Deficiency of the pectoral muscles”.1 This was based on dissections of the body of a deceased convict, Marc DeYoung. These dissections were conducted while Poland was still a medical student. He did not receive the eponym for the condition for more than a century. In 1962, Patrick Wensley Clarkson (1911–1969), a British surgeon operated on a case similar to that of Poland and attributed the description, quite rightly, to Poland.
Absence of the sternal component of the pectoralis major and the associated breast anomalies can be also associated with several other malformations, though presence of all of these phenomena is rarely seen and presence or absence of these associated lesions is not necessary to make the diagnosis of Poland syndrome. Absence of the pectoralis minor muscle is frequently seen in patients with this condition. Furthermore, aplasia or hypoplasia of ribs 3–5 have been reported. In fact, ipsilateral anomalies of the hand, lower arm or even the entire upper limb have been associated with Poland syndrome. These have ranged in severity from a simple partial syndactyly, to a complete mitten hand. Occasionally, digital anomalies are also associated, particularly in digits 2, 3 and 4. This has led to descriptions of shortened hands and even limbs in association. Several theories have been advanced to explain these anomalies. These include the temporary disruption of blood supply to the subclavian/vertebral systems during weeks 6–7 of embryological development. Another theory is that there is disruption of the mesodermal plate during weeks 3–4 of embryonal development. Though this syndrome appears sporadically, a small number of patients appear to have a heritable component to their condition.
The most frequent presentation is that of chest wall asymmetry. In both male and female, this is often unnoticed in childhood. In boys it generally is noticed at full or near full skeletal maturity whereas in girls, it is generally noticed at the time of breast development. It should always be suspected in a young patient presenting with chest wall deformity. At presentation, a full history should be taken. Physical examination should include examination of the chest wall, and, particularly, palpation of the ribs, looking for hypoplasia. The status of the pectoralis major and minor, latissimus, serratus anterior muscles should be documented. Also, the ipsilateral upper limb should be carefully examined with particular attention being paid to the hand, looking for syndactyly and digital abnormalities. Imaging tests (such as chest X-ray, ultrasound, CT scan, or MRI – and what the indications for these are), etc. should be used. There has been a diagnosis of Poland syndrome made by mammography in the past, with a rate of 1 : 19 000.
In all groups of patients, the absent sternal head of the pectoralis muscle should be replaced by anterior transposition of the ipsilateral latissimus dorsi muscle. The following minimal incisions are used in these usually young patients:
1. The latissimus muscle flap is harvested through a dorsal incision positioned above the lateral border of the muscle: this 5–8 cm long incision can be either vertically or horizontally oriented. The S-shaped vertical incision proposed in 1985 provides easy visualization of the whole muscle.2,3 However, a straight incision along the brassiere line is easier to hide and is the authors’ current preferred option.4 Through this approach, the entire surface of the anterior fascia of the latissimus dorsi is detached from the subcutaneous layer. The deep surface of the muscle is then freed from underlying structures. Care must be taken at the inferior angle of the scapula in order to avoid dissection under the Teres major muscle. The inferior border of the muscle flap is then severed as distally as possible using bipolar forceps.
2. An incision positioned in an axillary horizontal crease is used to gain access to the posterior axillary fold: the latissimus dorsi muscle is freed until the tendon is reached. The tendon is then transected at its insertion on the humerus. The whole muscle is isolated on the thoracodorsal neurovascular pedicle as in a microsurgical operation. The tendon is then sutured to the anterior bicipital sulcus of the humerus, in the position where the pectoralis major is inserted when anatomy is normal.