What is Turbinate Hypertrophy?
Turbinates are two spongy curled bones that protrude into the nasal passages. They are located bilaterally on both sides of the nasal cavity and are separated by the nasal septum. Turbinates are covered by respiratory epithelium covering a thick layer of vascular tissue. Anatomically, the structures are layered from near the floor of the nose to the top of the nasal cavity and are referred to as the inferior, middle and superior turbinates. The inferior turbinate is the largest and functionally most important turbinate.
Turbinates are responsible for conditioning the inhaled air
The turbinates are responsible for directing the airflow inside the nasal cavity. The name “turbinate” actually comes from the word turbulence- meaning the irregular flow of water or air. Respiratory epithelium covering the turbinates plays an important role in humidifying, heating and filtering the inhaled air. Humid air helps to prevent potential damage to delicate olfactory receptors located in the nasal cavity. These receptors are responsible for recognition of odors. The epithelium also represents a first line of immunological defense providing access to the lymphatic system. This is a place where immune-competent cells reside. The cells trigger quick immune response in the form of an inflammatory reaction at the signs of microbial or chemical irritation.
Turbinate hypertrophy can develop in response to various environmental factors and infections
Mucosal membranes covering the turbinates contain a large supply of blood vessels and can easily shrink or swell in response to various factors. As a result, turbinates can expand due to allergies, chemical or physical irritants, temperature changes, or infections which will congest the nose. This enlargement is reversible and turbinates normally will return back to normal size. However, persistent inflammation, allergic reactions and exposure to various environmental irritants may lead to the chronic swelling of the turbinates (usually inferior turbinates), resulting in a condition referred to as turbinate hypertrophy. Enlargement of the turbinates results in difficulty breathing through the nose. Troubles with breathing at night and snoring are common in such cases. Also, turbinate hypertrophy is associated with chronic sinus infections and nosebleeds that can potentially stem from an untreated deviated septum.
Septal deviation can lead to turbinate hypertrophy
The nasal septum is a bone and cartilage structure between the two nostrils that separates the nasal cavities into a left and right side. A perfectly straight nasal septum is rarely ever seen. It is estimated that around 80% of people have some degree of moderate to severe nasal septum deviation. Significant deformity of the nasal septum, either congenital or traumatic, can lead to compensatory turbinate hypertrophy. It is rather common for doctors to see patients who have one side of the nose blocked due to a deviated septum, and the other side obstructed due to hypertrophy of inferior turbinate.
Treatment of turbinate hypertrophy
Removal of irritating factors or treatment of underlying allergies can diminish the swelling of turbinates. Nasal steroid sprays can reduce mucosal inflammation and improve nasal breathing caused by turbinate hypertrophy.
However, when the bony structure of turbinates is enlarged, a surgery addressing the underlying problem may be required. Turbinoplasty (turbinate reduction) aims to reduce the size of the turbinates to help open the nasal airways. It can be performed in conjunction with rhinoplasty (correction or reconstruction of the nose) or septoplasty (straightening of the septum).
There are several surgical techniques that can be used to reduce the size of the turbinates. Some methods involve the removal of some of the turbinates’ bony structure, while others help to achieve the shrinkage of turbinates by reducing the existing soft tissue. One of the commonly used techniques, radio-frequency reduction, relies on heating up a part of turbinates using a special electrical device. The heated tissue gradually become scarred which helps in reducing the size of turbinates. Another technique is stereotactic image-guided surgery, which uses non invasive three dimensional diagramming.
Turbinoplasty involves making an incision at the mucosa lining of the turbinates, and removing a section of the bony structure. A device called microdebrider is commonly used for this procedure. This device drastically reduces the surgical time needed. A partial turbinectomy involves surgically removing the forward end of the inferior turbinate, thereby removing a portion of both the bone and mucosa.
References and comments:
- This Wikipedia article provides a detailed description of the structure and function of turbinates. The article also contains relevant illustrations.
- This article analyses the connection between septal deviations of different origin and the inferior turbinate hypertrophy. Findings support the excision of inferior turbinates in conjunction with septoplasty.
- Detailed analysis of medical and surgical management of turbinate dysfunction.