Effects of nasal wall lateralization and pyriform turbinoplasty on nasal air conditioning

Background: The inferior turbinate, as part of the nasal valve area, plays a key role in directing the airflow and moisturizing and heating the inspired air. Excessive resection of the inferior turbinate leads to a significant reduction in heating and humidification of inhaled air. Different types of turbinate surgery are described in the current literature. Pyriform Turbinoplasty is a new endoscopically performed procedure which includes a submucosal reduction of the bone of the frontal process of the maxilla and the lacrimal bone yet it preserves the mucosal surface. This new surgical technique is able to improve nasal airflow without hampering nasal climatization. Objective: Effects of Nasal Wall Lateralization and Pyriform Turbinoplasty on nasal climatization were analyzed using Computational Fluid Dynamics. Methods: A three dimensional model of the nasal cavity and paranasal sinuses was created basing on the CT-scans of a patient with nasal obstruction and hypertrophy of the inferior turbinates. The simulation was performed using transient boundary conditions and a breathing cycle with a length of 4.2 seconds. Results: Nasal resistance was reduced after performing Nasal Wall Lateralization and Pyriform Turbinoplasty. The main area of airflow and humidification increased and was elevated from the inferior to the medial turbinate. A homogeneous distribution of airflow around all nasal turbinates was observed. In contrast to many other techniques that include partial resection of the inferior turbinate, heating and humidifying of respiratory air during inspiration takes place in the entire nasal cavity postoperatively. Conclusion: Pyriform Turbinoplasty and Nasal Wall Lateralization are endoscopic procedures that widen the nasal valve area without mucosal resection. Computational Fluid Dynamics prove that these procedures produce a homogeneous distribution of airflow along the inferior and middle turbinate. The Pyriform Turbinoplasty and the nasal wall lateralization substantially improve nasal breathing without altering nasal climatization essentially. Correspondence to: Fabian Sommer, University Hospital Ulm, Department of Otorhinolaryngology, Head and Neck Surgery, Germany Received: November 15, 2016; Accepted: December 15, 2016; Published: December 19, 2016 Introduction Many different types of turbinate surgery have been described including partial and total turbinectomy, turbinoplasty techniques, electrocautery, laser cautery, radiofrequency, laser therapy, microdebrider submucous reduction and ultrasound turbinate reduction. There is no general agreement or recommendation which surgical technique is most effective in improving nasal breathing and does not harm nasal physiology [1,2]. In previous studies it has been demonstrated that the nasal valve area, which includes the head of inferior turbinate, is the most influential region to effect humidification and heating of inspired air [3-5]. The nasal valve area is formed by the septum medially, the caudal margin of the upper lateral cartilages laterally, the floor of the pyriform aperture and, finally, the head of the inferior turbinate. It represents a three-dimensional space [6]. The inferior turbinate, as part of the nasal valve area, plays a key role in directing the airflow and moisturizing and heating the inspired air. The inferior turbinate increases nasal resistance and simultaneously enables the mucosa to come into direct contact with large amounts of inspired air. For that reason, all surgical procedures regarding the inferior turbinate influence intranasal air conditioning, in a positive or negative sense. Additionally, the effect of the nasal cycle must be taken into consideration [7]. Excessive resection of the inferior turbinate leads to a significant reduction in heating and humidification of inhaled air [8-10]. Nasal air conditioning is more influenced by medial than inferior resection of the turbinate. Yet nasal resistance curves reveal no relevant changes between these in virtual surgery [11]. Partial reduction of hypertrophic turbinates results in improved nasal aerodynamics, which is most evident following resection of the lower third [12]. Partial reduction of the inferior turbinate can maintain its heating capacity whereas extensive or total turbinate resection can lead to significant impairment in the heating function of the nose [13]. Mucosa-preserving surgical techniques in turbinate surgery are able to improve both nasal airflow and air conditioning that has been demonstrated in recent in-vivo measurements [14,15]. Pyriform Turbinoplasty is a new endoscopically performed Sommer F (2016) Effects of nasal wall lateralization and pyriform turbinoplasty on nasal air conditioning Volume 2(1): 2-5 Otorhinolaryngol Head Neck Surg, 2016 doi: 10.15761/OHNS.1000135 procedure which includes a submucosal reduction of the bone of the frontal process of the maxilla and the lacrimal bone (Figure 1a and 1b) yet it preserves the mucosal surface. Due to this technique, part of the lateral margin of the nasal valve area is opened by forming a mucosal flap. The resection of bone in this area can be extended by a “Nasal wall lateralization”. Here, the lacrimal bone that joins the uncinate process behind the lacrimal duct as well as the base of the inferior turbinate and the edge of the maxilla at the rim of the pyriform aperture is removed. This new surgical technique is able to improve nasal airflow [16]. The tremendous advantage of this technique is minimal damage to the mucosa because the Pyriform Turbinoplasty is directed at the bone changing the architecture without removing any of the mucosa of the inferior turbinate. A significant improvement in ventilation after performing a Pyriform Turbinoplasty has been demonstrated [17]. The aim of this study was to analyze the effect of the Pyriform Turbinoplasty on intranasal heating and humidification of inspired air before and after surgery. This was realized by using Computational Fluid Dynamics (CFD) which are a valuable examination method regarding nasal physiology [5,7,18-20]. Materials and methods Pyriform turbinoplasty A 1 cm mucosal incision is made horizontally from the anterior lacrimal bulge towards the pyriform aperture. The head of the inferior turbinate is not easily lateralized as its bone is thick and often any lateralization is limited. The anterior aspect of the inferior turbinate is called the “shoulder” which comprises the frontal process of the maxilla and part of the lacrimal bone (Figures 1a and 1b). An inferior mucoperiosteal flap is folded downward by blunt dissection using a cottle elevator to expose the inferior part of the nasolacrimal canal and the maxillary conchal crest of the inferior turbinate (Figure 2a and 3b). This flap should ideally expose the piriform aperture. A 3mm osteotome is used to remove the maxillary conchal crest of the inferior turbinate and the antero-medial bone of the inferior part of the nasolacrimal canal while the membranous of the nasolacrimal duct are preserved (Figures 2b and 3d). Only a gentle tap is needed to mobilize this fragment of bone before it is dissected free and removed. The lacrimal duct lies just behind this segment of bone and it is important not to damage this. The mucosa can then be replaced over this area (Figures 2c and 3c). Nasal wall lateralization To gain space between the septum and the inferior turbinate one can continue the submucosal dissection more posteriorly to enable the entire inferior turbinate to be lateralized all the way back to its posterior attachment (Figure 4). Following a Pyriform Turbinoplasty the lacrimal duct is identified and pushed laterally to expose where the lacrimal fossa attaches onto the maxilla. The subperiosteal dissection can be extended more posteriorly by following the medial wall of the maxillary sinus until you reach the posterior attachment of the inferior turbinate to the pterygoid plate. The exposed bone posterior, lateral and inferior to the lacrimal duct is then freed using an osteotome. With gentle dissection this bone can be removed and then the mucosal flap can be repositioned (Figures 3d and 3f). This bone comprises the junction of the lacrimal fossa with the inferior insertion of the uncinate process and medial wall of the maxillary sinus. This results in a more substantial widening of the lateral nasal wall from the piriform aperture all the way back to the pterygoid bone. If there is an indication for a maxillary sinusotomy this technique can be extended to expose the primary ostium of the maxillary sinus in what is called an anterior approach to the sinus ostium (Figure 3e). This allows a maxillary sinus ostioplasty to be done by the submucosal removal of bone from the medial wall of the sinus as well as creating mucosal flaps that can cover any exposed area inferiorly. This is an elegant way of lowering the maxillary sinusotomy and preserving the overlying mucosa. This provides an entrance through which it is possible to visualize and operate on the maxillary sinus with straight instruments. At the end of this procedure when mucosal flaps have been placed in position, check that the maxillary sinusotomy is lower than the middle turbinate. The advantages of this procedure are direct access and visualisation of the ostium and by removing the maxillary 1a 1b Figure 1. 1a: A coronal CT-Scan showing the level of the “shoulder” of the inferior turbinate (red circle) and 1b the same area at the level of the pyriform aperture. 2a 2b 2c Figure 2. Diagrammatic representation of a pyriformturbinoplasty; left side. a: To define where the incision should be made the inferior turbinate is lateralized as much as possible and this reveals the “shoulder” which is too firm to outfracture with a freer‘s elevator. b: A mucosal flap is elevated and an osteotome is used to mobilize the shoulder and a piece of thick bone is then removed. c: The mucosal flap is replaced.