A deviated septum and obstructive sleep apnea (OSA) are two common respiratory conditions that frequently affect sleep quality. Many people who struggle to breathe through their nose wonder if this anatomical issue directly causes their sleeping disorder. While a deviated septum does not typically initiate the throat collapse that defines sleep apnea, it significantly worsens its severity and complicates effective treatment. This article examines how the nasal structure influences the lower airway and explores combined strategies to manage both conditions.
Anatomy and Impact of Deviated Septum
The nasal septum is the thin internal wall of bone and cartilage that divides the nasal cavity into two passages. A deviated septum occurs when this wall is displaced or crooked, meaning it is not perfectly centered. This common anatomical variation can be present from birth or result from an injury later in life.
When the septum is significantly off-center, it makes one or both nasal passages smaller, creating a physical nasal obstruction. This structural narrowing restricts airflow and increases nasal resistance to breathing. The reduced airflow causes difficulty breathing through the nose, which is often more noticeable when lying down or when the nasal lining swells due to allergies.
Defining Obstructive Sleep Apnea
Obstructive Sleep Apnea (OSA) is a serious sleep disorder characterized by repeated episodes of partial or complete upper airway collapse during sleep. As the body enters deeper sleep cycles, the muscles supporting the soft tissues of the throat, including the tongue and soft palate, relax. This relaxation allows the tissues to collapse, temporarily blocking the airway.
These blockages are known as apneas (complete cessation) or hypopneas (partial reduction in breathing). They can last for ten seconds or longer and reduce the body’s oxygen levels. The brain senses this drop and briefly rouses the person from sleep to restore muscle tone and open the airway, often accompanied by a loud snort or gasp. This cycle can occur hundreds of times a night, leading to fragmented sleep and symptoms such as loud snoring and excessive daytime fatigue.
OSA is distinct from Central Sleep Apnea (CSA), where the brain fails to send signals to the breathing muscles. OSA is purely a mechanical problem involving the collapse of soft tissue in the throat. Severity is measured by the Apnea-Hypopnea Index (AHI), which records the average number of breathing events per hour of sleep.
The Relationship Between Nasal Obstruction and Sleep Apnea Severity
A deviated septum does not cause the soft tissue collapse defining OSA, but it is a significant factor that worsens an existing condition. When nasal passages are severely blocked by a septal deviation, the body is forced to rely on mouth breathing during sleep.
Mouth breathing is detrimental to the lower airway’s stability. Breathing through the mouth bypasses the nose’s natural filtering and humidifying functions, leading to a less stable pharyngeal airway.
Furthermore, the rapid flow of air through a narrowed nasal passage increases the negative pressure created in the throat, known as the Venturi effect. This increased negative pressure makes the pharyngeal soft tissues more prone to collapse, increasing the frequency and severity of apneic events.
Studies show that surgically correcting nasal obstruction does not consistently reduce the Apnea-Hypopnea Index (AHI) to a non-apneic level, suggesting the nasal issue is not the primary cause of OSA. However, experimentally blocking the nose in healthy individuals can induce temporary sleep apnea, highlighting the nose’s role in maintaining airway patency.
Treatment Strategies for Improved Airflow
Managing the combined issues of a deviated septum and sleep apnea requires a coordinated approach addressing both nasal obstruction and pharyngeal collapse. The standard treatment for a deviated septum causing breathing difficulties is septoplasty, a surgical procedure. Septoplasty aims to straighten the nasal septum and reduce nasal resistance, improving airflow through the nose.
While septoplasty alone rarely cures OSA, it is valuable for improving a patient’s tolerance for the primary sleep apnea treatment, Continuous Positive Airway Pressure (CPAP). By correcting the nasal obstruction, septoplasty allows patients to breathe more comfortably through their nose while wearing the CPAP mask.
This improved nasal patency can significantly increase CPAP adherence. Reducing nasal resistance through surgery can also allow for a reduction of the required pressure setting on the CPAP machine. For less severe nasal obstruction, non-surgical options may be used to temporarily reduce resistance and support easier breathing, including nasal steroid sprays, decongestants, or external nasal dilator strips.