Not all rhinoplasty procedures are performed for cosmetic reasons alone – a deformed exterior often indicates an equally significant deformity of the internal nose with impaired function.

Rhinoplasty reshapes both the internal and external components of the nose, so the functional and cosmetic aspects are invariably intricately intertwined. Functional surgery cannot be separated from cosmetic surgery because, in order to adequately restore function, the surgeon must often change the outside of the nose.

A typical example of this is deviation of the nose to one side of the face, which is often the result of a trauma. The deformity of the internal nose is often more extensive than the outside appearance indicates.

The subsequent procedure to restore full function includes repositioning the deviated nasal bones to the midline and a consequent change in the outside appearance of a straighter nose.

The nose is made up of a fleshy casing over cartilage, a little like a tent. In the same fashion as a tent, the support system can change the appearance of the covering. Understanding nasal airflow is a complex balance of the laws of fluid dynamics, in which changes in radius affect flow rate.

Difficulties in breathing through one or both nostrils, frequent sinus infections, headaches, snoring, absence of smell and taste, stuffiness and postnasal drip are all signs of improper nasal function. Breathing problems can be caused by variables such as thickening of the lining of the nose, due to allergies or sinusitis.

It can also be caused by fixed obstacles, which include the septum (which is rarely straight and can sometimes block the nasal passage), internal structures called turbinates or the internal nasal valve, which is the narrowest section of the airway.

Over time, nasal obstructions, both variable and fixed,  can affect the function of the lungs and heart, causing asthma, chronic bronchitis and heart attacks. In such patients, rhinoplasty can significantly improve not only their health but also their life expectancy.

The most common functional problem is a deviated septum (a midline cartilage structure that divides the nose into right and left sides). A severely deviated septum results in a blocked nasal airway and a visibly crooked nose. A functional rhinoplasty candidate patient may also have a nasal airway obstruction and an unattractive bump on the bridge.

Several areas of the nose should be addressed: the opening of the nose; the septum; the turbinates; and the internal nasal valve. The surgeon will also evaluate the back of the nose and the adenoids, which can be enlarged and contribute to difficulty breathing. Each of these areas can contribute to functional difficulty and may need to be addressed separately or together to achieve the desired results.

When there is a structural problem, the nasal structural support needs to be restored. One of the most common causes of nasal obstruction is internal valve collapse, which may be caused by trauma or previous surgery. The degree of collapse is determined by the angle of the valve to the septum and wall. Surgery to address this problem can affect the appearance even though the primary goal is to improve breathing by widening the airway.

Impairment of nasal breathing is considered a health problem and is typically covered by health insurance.

Surgical treatment can result in improved airflow and sense of smell. The 10,000 different scents that humans recognise as tastes are often actually flavours – so a majority of tasting food is actually smelling.

The loss of taste often associated with a cold when the nose is blocked is similar to the effect of nasal deformity. It is not uncommon for rhinoplasty that straightens the structure of the nose to actually heighten the senses of smell and taste by improving the airflow.

In any rhinoplasty, function must be considered along with aesthetics, which is why seeing an experienced surgeon is imperative. There is no ideal candidate for functional rhinoplasty, as each patient needs to be evaluated individually, assessing breathing, their nasal structure, overall health, expectations and goals, and prior surgeries.