Discussion
Neonatal facial palsy is a condition characterized by weakness or paralysis of the facial muscles that appears at birth or shortly after, typically manifesting as an inability to fully close the affected eyelid, a shallow nasolabial fold, lateral deviation of the mouth, and difficulty in sucking. It is an extremely rare disease, with only a few reported cases; the incidence in live births is 0.23% [1]. Clinically, it is defined as facial nerve palsy resulting from injury to the seventh cranial nerve at birth or shortly thereafter. High-risk factors for this condition include prolonged labor, cephalopelvic disproportion, large-for-gestational-age infants, epidural anesthesia, and the use of oxytocic agents [2].
The etiology of congenital neonatal facial palsy is complex and multifaceted, primarily due to external or environmental factors or congenital developmental issues before birth. External factors mainly include trauma, compression, iatrogenic injury, or infection during delivery, with 78% to 90% of cases being caused by perinatal trauma [1]. Common causes of congenital facial palsy include perinatal trauma, abnormal fetal position in utero, and compression during delivery [3]. Given the relatively superficial course of the facial nerve, it is susceptible to injury during childbirth. Possible mechanisms of injury include compression from instruments used to assist delivery, pressure on the fetal shoulder causing displacement of the jaw and head region, which can compress the facial nerve and cause facial weakness; additionally, the fetal head may be compressed against bony prominences of the mother's pelvis, such as the pubic ramus, ischial spine, or sacral promontory. In some cases, traumatic facial palsy can occur even without the use of forceps [4]. Our patient did not experience any of these conditions. A descriptive study [5] over four years found that with the reduced use of forceps, common causes of congenital neonatal facial palsy included positive end-expiratory pressure (PEEP) devices, intrauterine procedures, central nervous system or ear infections, and perinatal asphyxia. Furthermore, Aakash Pandita [6] reported three cases of neonatal facial palsy caused by excessive CPAP pressure on the facial nerve. Our patient had a history of non-invasive ventilator support but was a small-for-gestational-age infant who presented with left eye open and right eye closed on the first day of life and had concurrent ear deformities, ruling out compression as the cause.
Developmental congenital facial palsy is often bilateral and frequently associated with other syndromes, rooted in developmental abnormalities such as absent or hypoplastic cranial nerve nuclei, or absent or hypoplastic facial nerves. In rare cases, patients may present with unilateral facial nerve palsy and ear deformities. Developmental neonatal facial palsy is often associated with abnormalities of the outer ear and external auditory canal, with approximately 10-15% of patients having both auricular malformations and facial nerve palsy, ranging from minor defects to complete auricular malformations or atresia, and about 1 in 20,000 live births presenting with auricular agenesis [7]. Syndromes associated with ear deformities and facial nerve palsy include cardio-facial syndrome, Moebius syndrome, and Poland syndrome. Cardio-facial syndrome involves spinal and cardiac defects; patients with Moebius syndrome have abducens nerve palsy; and patients with Poland syndrome have absence of the pectoralis major muscle [4]. In this case, the patient presented with unilateral facial nerve palsy and ipsilateral ear deformities. A brain MRI (including facial and acoustic nerve MRI) did not reveal any abnormalities in the course of the facial nerve or development of the facial nerve nucleus, and the clinical presentation did not match the described syndromes. The patient's facial nerve anatomy was normal, but the conduction function of the facial nerve was impaired. New genetic loci associated with congenital facial palsy have been identified in a few families [8]. There were no similar cases in the patient's family, and the parents declined further genetic testing.
Congenital facial palsy caused by delivery trauma is often temporary and usually resolves spontaneously within 3-6 months [9]. Compared to congenital facial palsy caused by external factors, developmental congenital facial palsy is more challenging to treat and has poorer outcomes. A multidisciplinary team consisting of otolaryngologists, pediatricians, ophthalmologists, plastic surgeons, and psychologists should develop a treatment plan. Initial treatment focuses on eye care to prevent visual abnormalities, monitoring hearing to prevent speech impairment, and avoiding the use of steroids, which have shown poor efficacy in treating developmental congenital facial nerve palsy [4]. Research [10] suggests that facial muscle training can be used as an adjunctive therapy to improve facial muscle control, inhibit synkinesis, and enhance emotional expression and functional movements to improve facial symmetry and reduce the severity of facial palsy. If the palsy affects normal development or quality of life, surgical intervention should be considered. In this case, the patient was treated with oral methylcobalamin and vitamin B1 tablets combined with physical therapy (acupressure), and treatment effectiveness was assessed through serial photography. The patient continues to be followed up by our multidisciplinary team.
The clinical diagnosis of congenital neonatal facial palsy is challenging, and delays in diagnosis are common. Because congenital facial nerve palsy with ear deformities due to developmental reasons is difficult to restore to a completely normal state, early diagnosis and treatment are crucial. This case report emphasizes the importance of early diagnosis in the neonatal period to prevent potential visual and auditory impairments and psychological issues, and to identify the underlying cause and implement appropriate interventions to improve facial function.
