What is a cleft?

Cleft lip and palate is the most common congenital oro-facial malformation. It affects approximately 1 in 700 live births with considerable geographic and racial variation. Worldwide, 15000 children are born each hour. This equals one child with a cleft being born every 2.5 minutes. In India, there are 32,000 per annum.

Why do they occur? As with any disorder, these malformations are the result of a combination of genetic and environmental factors. For example, malnutrition which may be due to poverty resulting in a deficient diet. Other possible factors are exposure to certain drugs during the first trimester, or exposure to radiation, or cultural habits such as consanguinity.  Due to poor development of the anatomy, there are problems with appearance, speech and hearing.

Clefts represent a major impact on feeding, appearance, speech and hearing, psychological well-being and integration into the community.

They represent potentially long-term consequences for the affected person of an emotional and cultural nature due, in particular, to their appearance and poor communication, and there is a burden of care for the family and the State, where the tensions of the economic status of a particular region are often at odds with cultural beliefs.

Oral and facial clefts develop during the first four to eight weeks of pregnancy when lip and palate tissues would normally fuse together. If these tissues do not join properly, the result is a cleft, the type of which can vary, being unilateral (one side) or bilateral ( both sides). They may involve just the soft tissues or both soft and hard (bony) tissues. On average, about 25% are cleft of the lip only, 25% are cleft lip and palate and 50% are cleft palate alone. 20% are associated with underlying genetic or chromosomal disorders.

Depending on the extent of the cleft, some represent greater challenges to the patient, family and carer. But the principal aim of surgery is to restore, as close to normal, appearance and speech with the establishment of good function through careful muscle reconstruction. In turn and with time, this leads to the best results in subsequent growth and development of the face.

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The anatomy of the non cleft face

The lower margin of the upper lip is called the vermilion and is characterized by its rosy colour. The line or ridge between the skin of the upper lip and the vermilion is called the white roll or mucocutaneous junction. The concave or dipped portion in the centre of the upper lip is called the Cupid’s bow and above this is a “dimple”, the philtrum, with raised ridges on either side. The upper lip is composed of the orbicularis oris muscle covered by skin on the outside and mucous membrane on the inside. Many other muscles are attached to the orbicularis oris muscle, and together they work to create the movements and power required for speaking, eating and forming facial expression. The orbicularis oris muscle constitutes the major bulk of the upper and lower lips.

The nose can be thought of as a tent of skin supported in the centre by a strut of cartilage called the nasal septum which separates the nose into the right and left chambers. The nasal septum also separates the two large sinuses underlying the cheek bones which are called the maxillary sinuses. The shelves on the lateral walls of the nasal cavities are called turbinates. The nostrils include the external ports or openings as well as the skin and cartilage surrounding them. In unilateral and bilateral cleft, the nostrils are mis-shapen. The palate is the roof of the mouth. It consists of two portions the hard (bony) palate and the soft, muscular palate.

The palate separates the nasal cavity from the oral cavity. The hard palate constitutes the anterior portion of the entire palate and lies directly behind a horseshoe-shaped bony arch within which lie the teeth. This arch is called the alveolus. The hard palate is immobile. The flesh that covers the hard palate is called mucoperiosteum. It is used in cleft palate repair to close the hard palate defect. The soft palate lies behind the hard palate. It ends with a little flap that hangs down from the soft palate called the uvula.

The soft palate is composed of several muscles and fibrous tissue (all of which is attached to the posterior edge of the bony palate). The soft palate is mobile and plays a decisive role in speech production. This primary function of the soft palate is dependent on the levator muscle. Reconstruction of this muscle is an important part of cleft palate surgery.

Behind the palate lies the pharynx or throat. The pharynx begins behind the mouth is called the oropharynx. The soft palate performs many functions. One of its roles is to close off the back of the nose during swallowing. This keeps food and fluids from being forced through the nose when a person eats and drinks.

The soft palate also plays a major role in speech. Since it acts like a veil over the pharynx, it is sometimes called the velopharynx. When the soft palate does not close completely or properly while making certain sounds, the patient is said to have velopharyngeal insufficiency or velopharyngeal incompetence. This functional impairment in cleft patients is marked with a nasal quality of speech called hypernasality.

The anatomy of the cleft face

The cleft is a splitting of tissue that occurs in the upper lip, alveolus and/or palate. The degree to which these structures are deficient, malformed or displaced depends on the form and severity of the cleft. The nose, which is not split, is severely affected by the split of anatomic structures at its base. If the split is one side of the lip it is called a unilateral cleft lip and if the split is on both sides it is known as bilateral cleft lip.

The cleft lip may be associated with cleft of alveolus and palate. The cleft could also be isolated to the palate only. This is known as isolated cleft palate.

Unilateral cleft lip and/or alveolus and/or palate

The unilateral cleft lip defect can be complete or incomplete. It can be associated with cleft of alveolus and/or cleft of palate. The unilateral cleft lip defect is formed by the improper fusion of the orbicularis oris muscle and its accessory muscle on one side. In a complete cleft the whole orbicularis oris muscle does not fuse but in an incomplete cleft part of the orbicularis oris develops normally.

Bilateral cleft lip and/or alveolus and/or palate

The bilateral cleft lip defect can also be complete or incomplete. It can also be complete on one side and incomplete on the other. It can also be associated with cleft of alveolus and/or cleft of palate. The bilateral cleft lip defect is formed by the non fusion of the orbicularis oris muscle over the premaxillary segment of the alveolus. In a complete cleft the whole orbicularis oris muscle does not fuse but in an incomplete cleft part of the orbicularis oris develops normally.

Cleft palate may be present without clefting of the lip and alveolus. It may involve only the soft palate, the soft and part of the hard palate, or the entire palate, soft and hard. The clefts, especially complete clefts of the palate, may vary in width.

The cleft palate is divided into the hard palate and the soft palate as mentioned earlier. Cleft of the hard palate involves the bony shelf of the palate that does not fuse leaving a gap down the centre of the palate. The cleft of the soft palate involves non-fusion of the soft palatal muscles, which are then abnormally attached.

Diagram of the muscles of the soft palate, cleft side on the left

It is common for children with cleft palate to have associated problems with the middle ear and therefore with hearing. Most of these problems are caused by a malfunctioning of the Eustachian tubes which are small passages that lead from the middle ear to the throat. Their function is to allow pressure to equalize on the inside of the eardrum or tympanic membrane. They also serve to drain any fluid that may accumulate in the middle ear. Yawning allows air to pass through the Eustachian tubes to relieve pressure on the eardrum. When the Eustachian tubes are not functioning properly, fluid can build up in the middle ear, sometimes called glue ear, causing discomfort and temporary or even permanent hearing loss. This is treated by inserting small drainage tubes called grommets into the ear drum. With surgical treatment and continued regular assessment and care, hearing loss can be prevented.