Techniques of Uncinectomy

Introduction

Anatomy Relevant to Uncinectomy

• A vertical segment (superior 2/3): attaches anteriorly to the lacrimal line (anterior maxillary line)
• A horizontal segment (inferior 1/3): attaches inferiorly to the inferior turbinate
• A free posterior edge facing the hiatus semilunaris
• Medially it forms the lateral wall of the middle meatus; laterally lies the lamina papyracea (LP)

• Attachment to LP (80%) → frontal drains medial to UP into middle meatus (recessus terminalis formed superiorly)
• Attachment to fovea ethmoidalis or middle turbinate (20%) → frontal drains lateral to UP into infundibulum

Key danger: the lamina papyracea (orbit) lies immediately lateral. Violation = orbital injury.

Instruments Used

Techniques of Uncinectomy

1. Retrograde Uncinectomy (Preferred / Standard Technique)

1. The uncinate process is identified with a 0° endoscope as a sickle-shaped structure. The posterior free margin (often with a rolled or everted edge when polyps present) is located.
2. A ball-tipped probe is slid into the infundibulum behind the posterior free edge to medialize the UP away from the lamina papyracea - especially useful when the UP is atelectatic over the orbit (Silent Sinus Syndrome).
3. A pediatric backbiter punch is introduced via the hiatus semilunaris and used to retrogradely incise the UP in an axial plane at the junction of the inferior 1/3 and superior 2/3 - this low position avoids inadvertent orbital penetration and corresponds to the natural maxillary ostium.
4. The incision is continued anteriorly until the harder lacrimal bone (anterior maxillary line) is encountered. Penetrating further damages the nasolacrimal duct.
5. The middle third is removed with cutting instruments or the microdebrider.
6. The superior third may be preserved (to prevent frontal recess scarring) or used later to assist frontal recess dissection.
7. The inferior horizontal segment is rotated medially with a maxillary sinus probe and removed with a downbiting instrument and microdebrider.

Steps in left-sided retrograde uncinectomy: (A) Initiation with backbiter; (B) Retrograde incision; (C) Lower 1/3 uncinate remaining; (D) Maxillary os identified; (E) Probe in maxillary os; (F) Final antrostomy - Cummings Otolaryngology

2. Anterograde (Antegrade) Uncinectomy

1. A sickle knife (or Freer elevator) is used to make a vertical incision starting on the anterior aspect of the uncinate.
2. The incision is continued inferiorly and posteriorly along the crescent-shaped anterior margin of the UP.
3. The freed UP is then removed using graspers or microdebrider.

3. Backbiter Technique (Inferior Uncinectomy Incision)

• Either adult or pediatric back-biting forceps are introduced behind the posterior free margin at the transition zone of the vertical and horizontal segments.
• The incision is made anteriorly to the maxillary line (junction of anterior uncinate border and medial vertical buttress of the maxilla housing the nasolacrimal duct).
• Safer than the sickle knife inferiorly due to reduced risk of orbital entry.

Pediatric back-biting forcep for inferior uncinectomy incision - Scott-Brown's Otorhinolaryngology

4. Standard KJ Lee Sequence (Step-by-Step Protocol)

5. Removal of the Horizontal Segment (Inferior Uncinectomy)

• The horizontal portion extends inferior to the natural ostium of the maxillary sinus.
• Bone of the horizontal portion is dissected free from the mucosa.
• The natural ostium can be stretched open with an angled probe or sucker without removing mucosa (for minimal disease).
• For advanced disease or revision cases, mucosa is removed to create a large middle meatal antrostomy.
• Angled through-biting forceps or the UP can be dislocated forward using a double right-angled ball probe and cautiously removed with the microdebrider.
• Rough edges are removed with a 2 mm Kerrison's punch.

6. Microdebrider-Assisted Uncinectomy

• Used as an adjunct after initial incision with a backbiter or sickle knife.
• The uncinate is mobilized (medialized off the LP) and then the microdebrider is used to resect the freed uncinate in a controlled manner.
• Reduces traction, minimizes mucosal trauma, and handles difficult anatomy (atelectatic UP, polypoid disease) more safely.
• Particularly useful in revision cases where landmarks are distorted.

Key Hazards and How Techniques Address Them

Summary

• Retrograde uncinectomy is preferred - reduces orbital penetration risk (Cummings, KJ Lee)
• Sickle knife is safe superiorly but dangerous inferiorly (Scott-Brown's)
• Always address the horizontal segment - retained horizontal UP is the most common cause of incomplete uncinectomy and failed maxillary antrostomy
• Stop anteriorly at the maxillary/lacrimal line to protect the nasolacrimal duct
• Ball probe medialization of the UP before incision is a critical safety step in atelectatic UP