Nasal Biopsy
Blind nasal biopsy can be used to diagnose masses and inflammatory conditions. Advanced imaging (CT or MRI) prior to biopsy greatly aids in the diagnosis as well as helps to guide the biopsy procedure. Rhinoscopy allows visualization of the nasal passages and can directly guide biopsy attempts.
Summary of Procedure:
| Indications | Chronic nasal discharge. |
| Limitations | May not be diagnostic. |
| Complications | Hemorrhage, hemorrhage, hemorrhage (with potential for aspiration pneumonia).
Perforation of cribiform plate. |
| Contraindications | Bleeding disorder. |
| Supplies/instruments | Alligator forceps, rubber ear bulb. |
| Position | Sternal recumbency. |
| Restraint | Anesthesia |
Details of Procedure:
- Pack pharynx with a tied role of gauze with end sticking out of mouth (to facilitate removal after procedure). The gauze roll will decrease any blood or fluid from entering the trachea around the ET tube.
- Measure distance from tip of nose to medium canthus of eye. Mark this distance on the biopsy forceps (e.g., place some white tape to make a marker).
- Insert forceps via naris into ventral nasal cavity and direct the forceps until resistance (nasal tissue) is met. You might need to redirect several times before meeting resistance. Slightly withdraw the forceps and open them. Advance the open forceps into the tissue (where you met resistance) and press the open forceps into the tissue. Close forceps, and withdraw. Do not advance forceps beyond medial canthus of eye (this is to prevent penetration of the cribiform plate should forceps be inadvertently directly into dorsal nasal cavity).
- Submit sample for histology +/- culture.
- Remove gauze and recover animal slowly from anesthesia with head down.
- Alternative less traumatic technique: Fill rubber ear bulb with cold saline, direct tip into ventral nasal cavity as per passing nasoesophageal tube, LODGE FIRMLY into nasal cavity, and squeeze bulb with one large forceful action. It is recommended to wear protective eyewear and clothing for this procedure. Remove pharyngeal gauze and remove samples (if present).
Alternate procedure (especially useful if tumour is present):
- Attach a plastic cannula or large gauge intravenous catheter (with stylet removed) to a syringe.
- Measure the length of the cannula/catheter to the medial canthus and place a mark at this length.
- Introduce the cannula into the nasal passage through the nare. Resistance might be met as your cannula meets a nasal tumour.
- Advance the cannula into the tumour, and apply negative pressure with the syringe. Redirect several times, using negative pressure with each redirect.
- Remove the cannula, and expel tissue into formalin, or cytology samples onto slides.