Medium (1–2 cm) and/or large (> 2 cm) size nasal septal perforations
Nasal septal perforation without osteocartilaginous support
Rescue flap for nasal septal reperforation
History of cauterization or embolization of sphenopalatine artery
History of cauterization of anterior ethmoidal artery
History of dacryocystorhinostomy on the ipsilateral side of the flap
Understanding the vascular anatomy of the lateral nasal wall is crucial for harvesting the PLNW. 1, 2 The useful area of mucosa of the PLNW ( ▶ Fig. 12.1a, b) covers superiorly from the axilla of the middle turbinate, then goes inferiorly up to the piriform aperture until the floor of the nose, and inferiorly it goes to the posterior insertion of the inferior turbinate. Finally, a superior sagittal plane limits it extension at the level of the lateral wall of the maxillary sinus till the perpendicular plate of the palatine bone where the posterolateral nasal artery (PLNA) is found. Depending on the defect, one can use anteriorly or posteriorly based flaps. The anteriorly based flaps will receive most of its blood supply from the anterior ethmoidal artery branch of the ophthalmic artery and anterior-lateral nasal artery (ALNA) branch of the facial artery. Posteriorly based flap are based on the branches of the sphenopalatine artery, mainly from the PLNA ( ▶ Fig. 12.2). In the mucosa of the lateral nasal wall, the PLNA runs anteroinferiorly over the perpendicular plate of the palatine bone and gives branches to the middle and inferior turbinates and fontanelle. Lee et al 3 studied 50 cadaveric specimens and observed that the PLNA ran downward on the perpendicular plate of the palatine bone and then coursed a little posterior to the posterior wall of the maxillary sinus in 42% and anterior to the posterior wall in 18%. Wu et al 4 studied the vascular anatomy of the PLNA in 11 cadavers. They observed that the PLNA mean outer diameter is 1.10 ± 0.11 (range: 0.82–1.30) mm and enters the inferior turbinate on the superior aspect of its lateral attachment, 1 to 1.5 cm from its posterior tip, and divides in 2.50 ± 0.52 (range: 2–3) arteries as part of inferior turbinate circulation.
Fig. 12.1 (a) Incision of the lateral nasal wall flap. Right lateral nasal wall, cadaveric preparation. (a) anterosuperior incision; (b) anterior incision; (c) inferior incision; (d) posterior incision; (e) fontanelle incision; (f) maxillary line incision. (b) Schematic drawing of right posterior pedicle lateral wall flap. AEA, anterior ethmoidal artery; ALNA, anterior-lateral nasal artery; MT, middle turbinate; PLNA, posterior-lateral nasal artery; dotted line, surface of the right posterior pedicle lateral wall flap.
Fig. 12.2 Endoscopic photograph of the inferior turbinate arteries. PLNA, posterior lateral nasal artery; <, superior lateral inferior turbinate artery; >, inferior medial inferior turbinate artery; *, branch of the descending palatine artery to the inferior turbinate.
Regarding the anatomy of the flap, Alobid et al 5 conducted a study on 40 de-identified computed tomographic (CT) angiographies and 20 hemicranial cadaver specimens to correlate the area and length of the PLNW flap with the nasal septum in order to plan surgery for septal perforation. On CT angiographies they demonstrated an average PLNW flap area of 10.80 ± 1.13 cm2, with a septal area (22.54 ± 21.32 cm2) that was significantly larger than the total PLNW flap area (14.59 ± 1.21 cm2). The average length of the flap was 5.58 ± 0.39 cm, whereas the septum was 6.66 ± 0.42 cm; therefore, the PLNW flap is insufficient to reconstruct the entire septum. On the cadaver study, they showed that the length of the PLNW flap was 5.28 ± 0.40 cm. These results demonstrate that measurements obtained from CT scans are reliable data and similar to those found in the radiologic study, and one can repair at least 80% defect with a PLNW flap. Regarding anteriorly based flap for septal perforation, there is no evidence available, and even though it is feasible, the managing of the flap itself is difficult and it has a limited range of movement.
12.4 Surgical Steps
12.4.1 Sinonasal Cavity Preparation
Cottonoids impregnated with a solution of 1:10,000 epinephrine are placed in the nasal cavity bilaterally during the surgical setup. At the beginning of surgery, the sites corresponding to the planned incisions are injected with lidocaine 1% with epinephrine 1:100,000. One must avoid injecting the area adjacent to the flap’s vascular pedicle (i.e., it causes vasospasm of the pedicle potentially impairing its viability) and the inferior turbinate (i.e., it may be equivalent to an intravascular injection).
12.4.2 Detailed Surgical Technique
The PLNW flap is designed according to the size and shape of the defect. The floor and lateral nasal wall is infiltrated with a solution of bupivacaine (0.25%) containing epinephrine (1:100,000).
Incisions can be made with a monopolar electrocautery using an extended, insulated, needle tip (Valley Lab, Boulder, Colorado) or an extended Colorado tip (Stryker Corporation, Kalamazoo, Michigan). Alternatively, the mucoperiosteum can be incised with a contact laser, Cottle elevator, or any other sharp instrument of preference.
Start with an incision following the maxillary line (corresponded intranasally to the junction of the uncinate and the frontal process of the maxillary bone).
Then continue with an anterosuperior incision ( ▶ Fig. 12.3) that runs anterior to the axilla of the middle turbinate downward down to the piriform aperture in front of the head of the inferior turbinate.
The inferior incision ( ▶ Fig. 12.4) goes on the nasal floor from the posterior border of the hard palate to the anterior nasal spine. Then unite the anterosuperior incision with the inferior incision.
The pedicle’s posterior incision joins a sagittally oriented incision that extends over the superior aspect of the inferior turbinate, just inferior to the uncinate process. Posterior to the uncinate process, the incision can migrate superiorly to incorporate the fontanelle of the maxillary sinus. Alternatively, an ipsilateral maxillary antrostomy can be opened to facilitate the previously described incision.
At the most posterior aspect of this incision, the sphenopalatine foramen and its corresponding arteries will be encountered. In this step it is critical to preserve all the arteries, as the flap will nourish from them.
The flap is elevated subperiosteally with a Cottle or other periosteal elevator, and the dissection is continued along the medial aspect (bone) of the inferior turbinate.
The opening of the lacrimal duct is spared by curving the anterior horizontal incision around it or performing an elliptical incision around the opening. Once the incisions around the nasolacrimal duct are completed, the mucosa is elevated medially. It is useful to “greenstick” fracture of the inferior turbinate medially as this facilitates the visualization and elevation of mucoperiosteum from its meatal aspect.
The remaining mucosa of the lateral aspect of the inferior turbinate and the inferior meatus is elevated, and the residual turbinate bone is removed with rongeurs or through-cutting instruments.
Once the flap is harvest ( ▶ Fig. 12.5), the perforation edges are rimmed to obtain fresh margins.
The flap is sutured with absorbable suture to the surrounding tissue. Usually sutures are placed anterosuperiorly, anteroinferiorly, posterosuperiorly, and posteroinferiorly ( ▶ Fig. 12.6a, b).
Silastic sheets are inserted to support the flap and prevent adhesions. The floor and lateral nasal wall are left bare for closure by secondary intention.
Patients are advised to use saline douches to minimize crust formation.
Division of the pedicle and suture of the posterior margin of the flap, under general anesthesia, is done 3 months postoperatively.
Fig. 12.3 Endoscopic view, 45-degree scope. Left lateral nasal wall anterosuperior incision (black arrow). MT, middle turbinate.