Trans-canine-fossa maxillary sinoscopy for biopsy via the Stammberger technique.

A wide variety of masses can arise in the maxillary sinuses. Pathologies range from polyps, cysts, and other benign entities to a number of malignant processes. One way of evaluating a mass in the maxillary sinus is to obtain a transnasal biopsy from the middle meatus. However, this technique can be exceedingly difficult to perform, depending on the position of the mass. Another way to biopsy such a mass is via the canine fossa approach as described by Draf [1] and Stammberger. [2]

To perform the trans-canine-fossa maxillary sinoscopy procedure, locate the canine fossa, which lies between the canine and the first premolar, and inject the area with a local anesthetic. Place a sinoscopy trocar with sheath (length: 8.5 cm; outer diameter: 5 mm) at the superolateral aspect of the fossa (figure, A). The direction to which the trocar is pointed is of utmost importance. The trocar should be pointed posteromedially because this is typically the direction of greatest sinus depth.

Apply pressure with a careful to-and-fro rotating movement until the trocar penetrates the maxillary sinus. The width of the anterior maxillary wall bone will determine how much pressure is required. As the pressure is applied, the surgeon must be careful to properly brace himself for the passage of the trocar into the sinus.

Once the trocar is passed into the sinus, withdraw it and leave the sheath in place. The sheath allows for the passage of a 4-mm telescope, which can provide a full view of the maxillary sinus. At this point, use a 0[degrees] scope to visualize the mass in question. The mass should be centered within the scope's field (figure, B). Without moving the sheath, withdraw the scope, pass a biopsy forceps through the sheath, and take the biopsy blindly (figure, C). Withdraw the forceps and reinsert the scope to revisualize the area to confirm that the biopsy was taken correctly (figure, D). Stammberger writes that with some experience, the surgeon should find this to be faster and more effective than using an optical biopsy forceps. [2] Two other advantages of this method are that it allows the surgeon to biopsy masses in difficult sinus positions and it can be performed in an outpatient setting.

Prior to any trocar placement, the surgeon must study the appropriate sinus radiographs to determine if there are any anatomic variations of the sinus. This will help determine the optimal angle for trocar introduction and thereby avoid complications. [1-3] If the trocar is placed too inferiorly within the canine fossa, it might damage one of the tooth roots. If it is placed too medially, it might penetrate the antral wall and enter the nasal cavity. [1] More worrisome complications are disruption of the lacrimal duct and violation of the lateral sinus wall, which could disrupt the soft tissues of the face. If the trocar enters the pterygomaxillary space, it could damage the internal maxillary artery, the infraorbital nerve, or branches of the trigeminal nerve. Finally, the surgeon should be most careful not to point the trocar toward the orbit because this could result in blindness; it might be helpful to palpate the inferior orbital rim during the procedure to reinforce the limit of positioning.

References

(1.) Draf W; Pohl WE, trans. Endoscopy of the Paranasal Sinuses: Technique, Typical Findings, Therapeutic Possibilities. Berlin; New York: Springer-Verlag, 1983.

(2.) Stammberger HR. Functional Endoscopic Sinus Surgery. The Messerklinger Technique. Philadelphia: B.C. Decker, 1991.

(3.) Yanagisawa E. Atlas of Rhinoscopy: Endoscopic Sinonasal Anatomy and Pathology. San Diego: Singular Publishing Group, 2000.