A SMILE FOR THE MOEBIUS SYNDROME PATIENT

A letter from Dr. R. M. Zuker, The Hospital for Sick Children, Toronto

I am delighted to have been asked to comment on my work on facial paralysis in Moebius Syndrome. I have had a major interest in Moebius Syndrome over the last ten years and have been impressed with the needs of these children to produce some degree of facial expression. My efforts in this regard revolve around muscle transplantation and I will try to outline to you the procedure which we have found most useful.

Moebius Syndrome is a congenital condition of unknown etiology which involve nuclear agenesis of the 6th and 7th nerves. Frequently the lower cranial nerves specifically 9, 10 and 12 are also involved. The most striking feature is an expressionless face as the facial musculature does not develop or is inactive. Although usually complete the incomplete form shows some mobility of the lower portions of the face, specifically the platysmal muscles. Feeding issues are paramount initially but then the expressionless face takes on greater importance as the children begin to interact at age 3 or 4. The psycho-social implications are enormous and unfortunately the children are often rejected by their peers with devastating consequences to self image.

Our efforts have been directed at providing some degree of facial expressions and specifically a smile. Previous attempts at transposition of regional muscles lead to other problems with deformities in the cheeks or temples. Our efforts have been directed at transplanting a muscle to the face where it is revascularized and reinnervated.

A segment of the gracilis muscle is taken from the thigh. We usually use about 40-50% of the circumference of the muscle and a length of about 9-11 cm depending on the size of the child. Fortunately, the donor defect with the harvest of the gracilis muscle is inconsequential. The gracilis muscle is quite suitable for this as it has an appropriate vascular supply and a specific motor nerve supply.

A pocket is made in the face through a preauricular incision with a small sub mandibular extension. The muscle is so positioned in the face that when it contracts it will elevate the corner of the mouth and upper lip. The positioning of the muscle is crucial and great care must be taken to place it appropriately and securely. In order for the muscle to survive it is revascularized. This involves microvascular anastomoses to the facial artery and vena comites of the gracilis. In a 5 year old these vessels are approximately 1.3mm in diameter and consequently the operating microscope must be used for reliable results. Then the muscle is reinnervated. Obviously there is no 7th and another regional motor nerve must be found.

We have been pleased with the results of utilizing the motor nerve to the masseter. This is a difficult nerve to find as it enters the masseter from its under surface. It is found beneath the zygomatic arch and then traced into the muscle where it is divided and reflected toward the surface. Only a portion of the masseter innervation is utilized and thus chewing is not compromised. A very exact micro neural repair is carried out under high magnification with 11-0 nylon sutures with precise fascicle to fascicle alignment. The muscle reinnervates in approximately 3 months and then a similar procedure is carried out on the opposite side. With reinnervation of the second muscle a exercise programme is begun. This is designed toward increasing the excursion of the muscle and also achieving symmetry. Biofeedback is often helpful to achieve this.

The results have been exceptional. Facial animation is provided and with some training the child is able to elevate the corner of the mouth and upper lip and achieve facial expression. This has been of enormous benefit in terms of interpersonal communication, self esteem and acceptance by their peers.

Although the procedures are lengthy, lasting about 8 hours each, we have encountered few complications. The children tolerate the long procedures well and recover quite rapidly. Although far from perfect as it does not provide for immediate spontaneous activity, it does accomplish our goals of a realistic method to achieve facial expression. It is at the present time the best method available to aid these unfortunate children.

Ronald M. Zuker,MD, FRCS(C), FACS.,
Head, Division of Plastic Surgery
The Hospital for Sick Children
Professor of Surgery
Department of Surgery
The University of Toronto