Nasal valve collapse (NVC) is a physical condition that significantly restricts airflow through the nose, leading to difficulty breathing. This restriction occurs when the sidewalls of the nasal passage physically narrow or close inward during inhalation, creating a blockage. The nasal valve is recognized as the narrowest segment of the entire nasal airway, making it the primary point where minimal structural change can cause major obstruction. Understanding the factors that contribute to the weakening of this structure is key to effective diagnosis and treatment.
Understanding the Nasal Valve Structure and Function
The nasal valve is a functional area divided into two distinct parts: the internal and the external valve. The internal nasal valve is a slit-like opening located approximately half an inch inside the nose, representing the most flow-limiting area of the airway. It is formed by the triangular angle between the nasal septum, the upper lateral cartilage, and the head of the inferior turbinate.
The external nasal valve is the nostril opening itself, which is primarily supported by the lower lateral cartilage (alar cartilage). Both the upper and lower lateral cartilages are C-shaped components that provide the necessary spring-like tension to keep the nasal passages open. NVC occurs when the structural integrity of these cartilages or the surrounding soft tissue weakens. When this support fails, the negative pressure created by inhaling causes the sidewall to be sucked inward, restricting airflow.
External Factors Trauma and Surgical Complications
One category of causes involves external forces that acutely or progressively compromise the nasal structure, such as trauma. Direct, high-impact injury to the face or nose, common in sports accidents or falls, can fracture the nasal bones or permanently displace the upper and lower lateral cartilages. This structural disruption immediately destabilizes the valve area, leading to a static, or permanent, form of collapse.
A significant cause of NVC is iatrogenic, meaning it is a complication arising from a medical intervention, most often previous nasal surgery. Procedures like cosmetic rhinoplasty, especially those involving aggressive reduction of the nose’s size, can inadvertently remove too much supporting cartilage. Removing or over-resecting the lower lateral cartilage strips the external valve of its necessary support, often leading to a visible “pinching” of the nostril.
Surgical Complications
During a septoplasty or a dorsal hump reduction, the fibrous attachments between the nasal septum and the upper lateral cartilages may be disrupted. If these attachments are not adequately repaired or reinforced, the upper lateral cartilage loses its anchor, allowing the internal nasal valve to collapse inward. This loss of structural scaffolding may not manifest immediately but can result in progressive weakness that leads to valve failure months or even years after the initial surgery.
Internal Factors Congenital and Degenerative Weakness
The cause of nasal valve collapse is often rooted in the natural processes of aging or inherent anatomical predisposition. Aging is a common degenerative cause because the collagen and elastin fibers that provide strength and elasticity to the nasal cartilage naturally weaken and thin over time. This process creates a flaccid or droopy structure, which is particularly susceptible to dynamic collapse, where the valve only closes during the negative pressure of a deep breath.
Congenital Factors
Some individuals are born with anatomical variations that predispose them to NVC, even without a history of injury or surgery. These factors include naturally narrower nasal valves, weaker or poorly oriented cartilage, or a nose tip with long, thin nostrils. These anatomical characteristics mean the valve area starts with less structural reserve, making it more prone to collapse under normal breathing conditions.
Pre-existing Conditions
Pre-existing nasal conditions can also contribute to the development of collapse by placing chronic asymmetrical stress on the valve. A severely deviated septum (the wall separating the nasal passages) can physically push into the internal valve area, narrowing the passage and accelerating weakness. Chronic inflammation or hypertrophy (enlargement) of the inferior turbinates can crowd the internal valve region, forcing the lateral wall to compensate and eventually leading to secondary weakening and collapse.