Poland-Moebius Syndrome

Both the Poland and the Moebius syndromes are well-described malformations. The Moebius syndrome is characterized by multiple cranial nerve palsies, orofacial malformations, and limb anomalies. The Poland syndrome consists of unilateral symbrachydactyly and ipsilateral aplasia of the sternal head of the pectoralis major muscle. The association probably represents a formal genesis malformation syndrome of unknown etiology.

Moebius syndrome, anomalies first described by Henry Thomas in 1898. The Poland disorder was first described by Sir Alfred Poland in 1841.

1:32,000 to 1:87,550 live births for Poland syndrome.

Most patients with Poland syndrome are the result of mutation or sporadic with rarely familial (autosomal dominant) reports. Moebius syndrome is inherited as an autosomal dominant trait with the gene map locus localized to 13q12.2-q13. Alternately, all three genetic conditions may belong to the spectrum of the same syndrome; perhaps both syndromes are expressions of the same gene.

Poland syndrome and Moebius syndrome are each the result of interruption of the early embryonic blood supply in the subclavian arteries, the vertebral arteries and/or their branches. The term subclavian artery supply disruption sequence (SASDS) was suggested for this group of birth defects.

The Poland syndrome consists of usually unilateral absence of the pectoralis muscle, syndactyly, brachydactyly, and hypoplasia of the hand. Absence of ribs may result in paradoxical chest wall movement. Classically, lung herniation through the chest defect may be seen during crying or a Valsalva maneuver. Patients with Moebius syndrome are usually diagnosed soon after birth because of incomplete closure of eyelids during sleep, drooling, and difficulties in sucking. A “mask-like facies” is present, with the child not smiling or moving its facial muscles on crying. Moebius syndrome consists of bilateral palsies of cranial nerves VI and VII, but occasionally also cranial nerves V, X, XI, and XII, resulting in difficulties with chewing, swallowing, and coughing, often leading to aspiration with respiratory complications. Arthrogryposis, limb deficiencies, contractures of the fingers, and strabismus may also occur with this condition.

Patients with Poland syndrome do not often have any functional disability and can present either for diagnostic radiological procedures or for cosmetic breast reconstructive surgery. Associated anomalies may include cardiovascular (dextrocardia, atrial septal defect), musculoskeletal (scoliosis), genitourinary (renal aplasia, hypospadias, inguinal hernia), gastrointestinal (extension of liver through chest), and hematological (lymphoma, leukemia). Patients with Moebius syndrome have congenital paralysis of the sixth and seventh cranial nerves, resulting in esotropia and facial paralysis. Occasionally, cranial nerves V, X, XI, and XII are also involved, resulting in chewing, swallowing, and coughing, and repeated aspiration with respiratory complications. Patients with Moebius syndrome have a high incidence of other anomalies, including congenital cardiac disease, spinal anomalies, corneal abrasions, and peripheral neuropathies, and a careful preoperative assessment is essential. Affected children most commonly present for anesthesia for correction of strabismus, or for orthopedic procedures to improve limb function.

The presence of associated anomalies should be determined in patients and appropriate investigations ordered. Concomitant respiratory infections in patients with Moebius syndrome should be optimally treated prior to elective surgery. Investigations: arterial blood gas, chest radiograph, ECG, serum urea and electrolytes, cell blood count. Antisialagogue premedication to decrease pharyngeal secretions. Ensure full cardiac investigations, including echocardiography, if there is suspicion of any cardiac lesion. Ensure respiratory function is optimized and infections treated with appropriate antibiotics and physiotherapy. Chest radiograph to elucidate acute or chronic lung changes and/or chest wall deformity. Blood examination: urea, creatinine, and electrolytes if renal abnormalities are present. Arterial blood gas analysis if indicated by respiratory status.

Problems can arise during anesthesia for children with Moebius syndrome; there is a high incidence of difficult or failed tracheal intubation. The use of a face mask or laryngeal mask airway and spontaneous breathing technique is reported to be safe, although laryngospasm may occur from the accumulation of pharyngeal secretions and special attention should be given to this eventuality. The potential for problems with aspiration of oral secretions should be remembered and the use of antisialagogue premedication is recommended. In the Poland syndrome, unilateral absence of ribs leads to poor development of subatmospheric pressure in the thorax and paradoxical respiration, and may cause inadequate pulmonary ventilation and hypoxia. Positive-pressure ventilation is recommended to maintain ventilation during surgery. The anesthetic technique and the need for invasive monitoring is influenced by, among other factors, the presence and severity of cardiovascular disease and respiratory impairment secondary to the spinal anomalies. Ophthalmic ointments should be applied and the eyes taped closed to prevent further ocular complications in those patients with corneal injuries. Where a regional anesthetic technique is to be used, careful documentation of existing neuropathies should be done. Recurrent aspiration may cause acute and chronic pulmonary changes and increased oxygen requirement. Paradoxical chest movement during spontaneous ventilation may result in inadequate ventilation; therefore mechanical ventilation is recommended. A period of postoperative mechanical ventilation may be required to facilitate bronchial toilet in these patients. Antibiotic prophylaxis may be required for invasive procedures in the presence of cardiac defects. Renal aplasia requires care with fluid balance and administration of renally excreted drugs.

Antisialagogues such as atropine and glycopyrrolate are recommended to reduce upper airway secretions. Atracurium, cis-atracurium, and mivacurium are suitable muscle relaxants if renal aplasia exists. Suxamethonium should be avoided. If there is compromised respiratory function, extreme care should be taken with the administration of opioids and benzodiazepines.