Post-traumatic nasal cavity synechiae and choanal atresia

Understanding Nasal Synechiae and Atresia

Nasal synechiae and atresia are conditions characterized by abnormal tissue connections or blockages within the nasal cavity, leading to impaired nasal function. While the term "choanal atresia" specifically refers to a congenital blockage of the posterior nasal apertures, the broader terms "atresia" and "synechiae" can also describe acquired obstructions resulting from various insults to the nasal lining.

 

Definitions and Causes

• Nasal Synechiae: These are adhesions or scar bands that form between opposing mucosal surfaces within the nasal cavity, such as between the nasal septum and the turbinates, or between different parts of the lateral nasal wall. Synechiae can be localized to various parts of the nasal cavity.
• Nasal Atresia (Acquired): This refers to a complete or partial blockage or closure of a nasal passage that develops after birth. This is distinct from congenital choanal atresia.

The primary causes of acquired nasal synechiae and atresia include:

• Nasal Trauma: Injuries to the nose, including fractures or significant mucosal lacerations, can lead to abnormal healing and scar formation.
• Nasal Surgery: Procedures such as septoplasty, turbinate surgery, endoscopic sinus surgery, or polypectomy can sometimes result in synechiae formation if opposing raw mucosal surfaces heal together. This is one of the more common causes of postoperative synechiae.
• Nasal Packing: Prolonged or traumatic nasal packing.
• Cauterization: Aggressive or extensive cauterization of the nasal mucosa (e.g., for epistaxis).
• Burns: Thermal or chemical burns to the nasal cavity.
• Chronic Inflammatory Conditions: Severe or prolonged inflammation from conditions like chronic rhinosinusitis, granulomatous diseases (e.g., sarcoidosis, Wegener's granulomatosis/GPA), or infections can lead to scarring.
• Repeated Nasal Intubation or Instrumentation.

Congenital choanal atresia, by contrast, is a developmental anomaly present at birth where the posterior nasal passage (choana) fails to open into the nasopharynx.

Impact on Nasal Function

The presence of significant synechiae or atresia within the nose often leads to a disturbance of normal nasal physiology. Key functions affected include:

• Nasal Breathing: Obstruction to airflow is a primary symptom, leading to mouth breathing.
• Sense of Smell (Olfaction): If synechiae or atresia block airflow to the olfactory region (superior nasal cavity), the sense of smell can be impaired (hyposmia) or lost (anosmia).
• Resonator Function: The nose contributes to voice resonance; obstruction can lead to a hyponasal voice quality.
• Mucociliary Clearance: Scarring and adhesions can disrupt the normal flow of mucus, leading to stagnation of secretions and predisposition to infections like sinusitis.
• Paranasal Sinus Drainage: Obstruction of sinus outflow tracts by synechiae can lead to sinusitis.

 

Diagnosis of Nasal Synechiae and Atresia

Diagnosis is typically made through:

1. Clinical History: Inquiring about previous nasal trauma, surgeries, burns, chronic nasal conditions, and symptoms such as nasal obstruction, impaired smell, or recurrent sinusitis.
2. Anterior Rhinoscopy: May reveal visible adhesions or blockages in the anterior nasal cavity.
3. Nasal Endoscopy: This is the most important diagnostic tool, allowing for direct visualization of the entire nasal cavity, precise localization of synechiae or atretic segments, and assessment of their thickness and extent (e.g., mucosal, fibrous, cartilaginous, or bony).
4. Imaging Studies:
   • Computed Tomography (CT) Scan: Useful for evaluating bony atresia, the extent of scarring, associated sinus disease, and for surgical planning. Contrast may be used if an underlying inflammatory or neoplastic process is suspected.
5. Probing: Gentle probing under direct vision can help determine the nature and attachment of synechiae.

 

Surgical Treatment of Nasal Synechiae and Acquired Atresia

The primary treatment for symptomatic nasal synechiae and acquired atresia is surgical intervention aimed at restoring nasal patency and normal physiological airflow.

 

Principles of Surgical Intervention

The main goals of surgery are:

• To re-establish an adequate nasal airway.
• To ensure the air stream passes along the physiological channel, rising superiorly towards the olfactory region to facilitate smell.
• To free the natural openings of the paranasal sinuses from adhesions or obstruction to improve sinus ventilation and drainage.
• To restore overall physiological functions of the nose and paranasal sinuses, including breathing and olfaction.

Simply creating a canal along the floor of the nose during atresia repair may not be sufficient, as this does not restore the natural arcuate upward flow of air necessary for olfaction or proper sinus ventilation.

 

Techniques for Atresia Repair

The surgical technique for atresia depends on its nature (bony, cartilaginous, or soft tissue) and location:

• Bony Atresia: This is typically excised submucosally. If the atresia is located in the area of the piriform aperture (the bony entrance to the nasal cavity), submucosal bone excision is performed along its edge to widen the opening. Great care is taken to preserve as much healthy mucosa as possible to line the newly created passage.
• Soft Tissue or Cartilaginous Atresia: May involve excision of the obstructing tissue, often with mucosal flap reconstruction or grafting to prevent restenosis.

Operations for atresia are performed with the aim of restoring both nasal breathing and the sense of smell for the patient.

Techniques for Synechiae Excision and Prevention of Recurrence

Surgical intervention for synechiae consists of their precise excision. This is often done endoscopically with sharp instruments (e.g., sickle knife, microdebrider) or sometimes with a laser.

A significant challenge after synechiae lysis is preventing their recurrence as the opposing raw mucosal surfaces heal. Several methods are used to keep these surfaces separated during the healing process:

• Placement of Spacers/Stents: After excision, a non-adherent material is often inserted into the nasal cavity to separate the raw surfaces. Common materials include:
  • Celluloid sheets or X-ray film (cut to size).
  • Silicone sheeting or splints.
  • Foil (less common now).
  These materials are typically fixed in place, for example, with a silk thread that is brought out and secured externally (e.g., behind the ear or taped to the face with plaster). The spacer is usually left in the nose for a period of up to 10 days or more, depending on the extent of raw surfaces and healing progress.
• Nasal Packing: A light nasal tampon, often soaked in an antibiotic emulsion (e.g., 5-10% synthomycin emulsion), may be introduced into the nasal cavity for 1 day to provide initial hemostasis and separation.
• Meticulous Postoperative Care: Regular nasal saline irrigations and debridement of crusts and fibrin by the surgeon are crucial during the healing phase to prevent re-adhesion.
• Application of Mitomycin C: In some cases, topical application of Mitomycin C (an antimetabolite) at the time of surgery has been used to try to inhibit fibroblast proliferation and reduce scar formation, though its routine use is debated.

 

Congenital Choanal Atresia (Brief Overview)

While this article primarily discusses post-traumatic and acquired conditions, it's important to briefly mention congenital choanal atresia, as it is a significant cause of nasal obstruction from birth. This condition is a developmental failure of the posterior nasal cavity to communicate with the nasopharynx. It can be unilateral or bilateral, and the obstructing plate can be bony, membranous, or mixed.

• Bilateral Congenital Choanal Atresia: Presents as a neonatal emergency with severe respiratory distress (cyclic cyanosis, relieved by crying) because newborns are obligate nasal breathers. Urgent airway management and surgical repair are required.
• Unilateral Congenital Choanal Atresia: May go undiagnosed until later in childhood, presenting with persistent unilateral nasal obstruction and discharge.

Surgical repair is the definitive treatment, aiming to create a patent posterior nasal airway. Various techniques exist, including transnasal endoscopic approaches (often with drills or microdebriders) and, historically, transpalatal approaches.

 

Differential Diagnosis of Nasal Obstruction

Nasal synechiae and atresia must be differentiated from other causes of nasal obstruction, especially if the history of trauma or surgery is unclear:

Condition	Key Differentiating Features
Nasal Synechiae/Acquired Atresia	History of trauma, surgery, or chronic inflammation. Visible adhesions or complete/partial blockage on endoscopy. CT confirms bony/soft tissue obstruction.
Congenital Choanal Atresia	Present from birth (especially bilateral). Diagnosed by inability to pass catheter, endoscopy, CT scan showing atretic plate.
Deviated Nasal Septum	Midline cartilage/bone is bent, causing fixed obstruction. No adhesions unless complicated by trauma/surgery.
Turbinate Hypertrophy	Enlarged inferior or middle turbinates. Mucosa may be boggy or firm. No bridging scar tissue.
Nasal Polyps	Pale, grape-like, mobile masses, often from middle meatus. Usually bilateral in adults (unless antrochoanal).
Sinonasal Tumors (Benign/Malignant)	Often unilateral, may cause pain, bleeding, facial swelling. Mass visible on endoscopy/imaging. Biopsy required.
Chronic Rhinosinusitis with Severe Mucosal Edema	Diffuse mucosal swelling, purulent discharge. No fixed adhesions, though apposition of swollen surfaces can occur.
Nasal Foreign Body (long-standing)	Usually unilateral, foul purulent discharge. Object may be surrounded by granulation tissue that can mimic adhesions.

 

Complications and Prevention

Potential complications of untreated or inadequately treated synechiae/atresia include:

• Chronic nasal obstruction and mouth breathing.
• Persistent hyposmia or anosmia.
• Recurrent or chronic sinusitis due to impaired drainage.
• Recurrent otitis media (especially in children with significant nasopharyngeal obstruction).
• Sleep-disordered breathing.

Prevention of acquired synechiae involves:

• Meticulous surgical technique during nasal procedures to minimize mucosal trauma and preserve healthy tissue.
• Careful hemostasis during surgery.
• Use of spacers or stents between raw mucosal surfaces in high-risk situations.
• Good postoperative care, including saline irrigations and debridement.
• Prompt management of nasal trauma.

 

When to Consult an ENT Specialist

Consultation with an Ear, Nose, and Throat (ENT) specialist is necessary if:

• Persistent nasal obstruction occurs, especially following nasal trauma or surgery.
• There is a noticeable decrease or loss of the sense of smell.
• Symptoms of chronic or recurrent sinusitis develop.
• A newborn exhibits signs of severe respiratory distress or difficulty feeding that might suggest bilateral choanal atresia.
• Persistent unilateral nasal obstruction or discharge is noted in a child (to rule out unilateral choanal atresia, foreign body, or other pathology).

An ENT specialist can accurately diagnose the cause of nasal obstruction using endoscopy and imaging, and can perform the necessary surgical interventions to correct synechiae or atresia, aiming to restore normal nasal function.