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External nasal valve collapse — Clinical Guidelines

Overview

External nasal valve collapse, also known as external nasal valve dysfunction, is a condition characterized by the inward collapse of the lateral nasal alar cartilages, leading to compromised nasal airflow and often aesthetic deformities of the nasal tip. This condition significantly impacts both the functional breathing capacity and the cosmetic appearance of the nose, commonly affecting individuals post-rhinoplasty or due to congenital anomalies, aging, trauma, or iatrogenic causes. In day-to-day practice, recognizing and addressing external nasal valve collapse is crucial for achieving optimal outcomes in both aesthetic and reconstructive nasal surgeries 1 6 13 18 29.

Pathophysiology

The external nasal valve (ENV) is a critical zone for airflow regulation, situated between the nasal ala and the nasal vestibule. Pathophysiologically, collapse of the ENV often results from structural weaknesses or malpositions in the lower lateral cartilages (LLC). Specifically, cephalic malpositioning or concavity of the lateral crura can lead to inadequate support of the nasal alae, causing inward collapse during inspiration 1 13 18 29. This collapse not only restricts airflow but also contributes to aesthetic issues such as alar retraction and a pinched appearance of the nasal tip. Additionally, thick skin and soft tissue hypertrophy, particularly in East Asian patients, can exacerbate these functional and aesthetic problems 2.

Epidemiology

The incidence of external nasal valve collapse varies widely depending on the population and underlying causes. It is frequently observed post-rhinoplasty, especially in revision surgeries where previous interventions may have compromised the structural integrity of the LLC 1 6 13 29. Age and ethnic factors also play roles; older patients and those with thicker nasal skin, particularly in East Asian populations, may be at higher risk 2 11. While precise prevalence figures are not universally reported, clinical experience suggests that the condition is more prevalent in patients undergoing secondary rhinoplasties compared to primary procedures 1 13 29. Trends indicate an increasing awareness and diagnosis due to advancements in surgical techniques and patient expectations for both form and function 8 29.

Clinical Presentation

Patients with external nasal valve collapse typically present with symptoms of nasal obstruction, particularly during inspiration, and may report a sensation of nasal collapse or pinching at the nasal tip. Aesthetically, there is often observed alar retraction, a pinched appearance of the nasal tip, and overall narrowing of the nasal aperture. Red-flag features include severe breathing difficulties that impact daily activities and significant cosmetic dissatisfaction post-surgery. These presentations necessitate a thorough clinical evaluation to differentiate from other nasal pathologies 1 13 18 29.

Diagnosis

The diagnostic approach for external nasal valve collapse involves a combination of clinical assessment and specific diagnostic criteria:

Clinical Examination: Detailed inspection and palpation of the nasal alae to assess for concavity, alar retraction, and structural integrity of the lateral crura.

Functional Assessment: Nasal endoscopy and rhinomanometry to evaluate airflow dynamics and quantify obstruction.

Specific Criteria:

- Visual Inspection: Presence of alar retraction and nasal tip concavity. - Palpation: Weakness or inward collapse of the lateral crura during inspiration. - Rhinomanometry: Reduced nasal airflow resistance indicative of valve dysfunction. - Grading Systems: Utilization of grading scales such as the External Nasal Valve Efficacy Index (ENVEI) to quantify severity 21.

Differential Diagnosis:

- Internal Nasal Valve Dysfunction: Distinguished by symptoms localized to the nasal septum and assessed via endoscopic evaluation. - Inferior Turbinate Hypertrophy: Identified by enlarged turbinates visible on examination and responsive to decongestant trials. - Aging and Thin Skin: Characterized by generalized nasal changes rather than localized collapse 1 13 18 29.

Management

First-Line Management

Conservative Measures:

- Nasal Dilators: Use of external nasal dilators to improve airflow temporarily. - Surgical Techniques: - Cephalic Lateral Crural Advancement (CLCA): Advancing the lateral crura to provide better support and prevent collapse 1. - Lower Lateral Crural Reverse Plasty: Correcting severe concavities of the lateral crura to restore structural integrity 29. - Lateral Crural Reinforcement Grafts: Utilizing grafts like the sandwiched lateral crural reinforcement graft to stabilize weak lateral crus 24.

Second-Line Management

Advanced Surgical Interventions:

- Rainbow Graft Technique: Replacing lower lateral cartilages to improve tip projection and correct external valve dysfunction 25. - Hybrid Dorsal Preservation Rhinoplasty: Ensuring proper dorsal aesthetic lines while addressing structural weaknesses 5. - External Cantilever Sling: Employing this technique in septorhinoplasty to manage severe deviations and support the nasal structure 37.

Refractory Cases / Specialist Escalation

Revision Rhinoplasty: Referral to experienced rhinoplasty surgeons for complex reconstructions involving multiple grafts and advanced techniques.

Alloplastic Grafts: Consideration of materials like porous polyethylene or titanium mesh for severe structural deficiencies 16 39.

Contraindications

Active Infections: Avoid surgical interventions until infections are resolved.

Severe Systemic Diseases: Postpone surgery in patients with uncontrolled systemic conditions that could impair healing 1 13 18 29.

Complications

Acute Complications:

- Scar Tissue Formation: Potential for hypertrophic scarring, particularly with external approaches. - Nasal Obstruction Persistence: Inadequate correction leading to continued breathing difficulties.

Long-Term Complications:

- Alar Retraction: Persistent aesthetic deformities requiring further surgical intervention. - Implant-Related Issues: Infection, migration, or extrusion of alloplastic materials 1 13 18 29.

Prognosis & Follow-Up

The prognosis for external nasal valve collapse varies based on the severity and timeliness of intervention. Early diagnosis and appropriate surgical correction generally yield favorable outcomes with restored nasal function and improved aesthetics. Prognostic indicators include the initial structural integrity of the LLC and the skill level of the surgeon. Recommended follow-up intervals typically include:

Initial Follow-Up: 1-2 weeks post-surgery to assess healing and address immediate complications.

Subsequent Follow-Ups: Every 3-6 months for the first year to monitor long-term stability and functional outcomes 1 13 18 29.

Special Populations

Pediatric Patients: Nasal growth considerations necessitate conservative approaches and careful monitoring of developmental changes 41.

East Asian Populations: Thicker skin and soft tissue require specialized techniques like supratip excision and cartilage reshaping to address bulbous tips and external valve issues 2.

Elderly Patients: Increased risk of complications necessitates meticulous surgical planning and possibly staged interventions 1 13 18 29.

Key Recommendations

Perform Comprehensive Preoperative Assessment: Include detailed clinical examination and functional assessments like rhinomanometry to identify external nasal valve dysfunction (Evidence: Moderate) 1 13 18 29.

Utilize Advanced Surgical Techniques: Employ techniques such as cephalic lateral crural advancement and lateral crural reinforcement grafts for structural support (Evidence: Strong) 1 24 29.

Consider Patient-Specific Factors: Tailor surgical approaches based on ethnic characteristics (e.g., thicker skin in East Asian patients) and individual anatomical variations (Evidence: Moderate) 2 11.

Monitor for Complications: Regular follow-up to detect and manage complications such as scar tissue formation and persistent obstruction (Evidence: Moderate) 1 13 18 29.

Refer Complex Cases to Experts: Escalate to experienced rhinoplasty surgeons for revision surgeries involving multiple grafts and advanced techniques (Evidence: Expert opinion) 1 13 18 29.

Use of Functional Assessment Tools: Implement tools like the External Nasal Valve Efficacy Index for objective grading of severity (Evidence: Moderate) 21.

Avoid Overpacked Instrument Trays: Optimize surgical efficiency by using only frequently utilized instruments in rhinoplasty procedures (Evidence: Expert opinion) 10.

Consider Alloplastic Materials Cautiously: Evaluate the use of alloplastic grafts like porous polyethylene for severe structural deficiencies, weighing risks and benefits (Evidence: Moderate) 16 39.

Address Aesthetic and Functional Goals Simultaneously: Ensure surgical interventions aim to correct both aesthetic deformities and functional impairments (Evidence: Moderate) 1 13 18 29.

Educate Patients on Post-Operative Care: Provide detailed instructions to minimize complications and ensure optimal healing (Evidence: Expert opinion) 1 13 18 29.

References

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External nasal valve collapse