Severe caudal cartilage deviation frequently involves the L-strut, and symptom improvement in patients with caudal septal deviation is not likely to be achieved without direct modification of the L-strut. However, most surgeons inevitably adopt defensive measures to avoid postoperative cosmetic issues. Surgical techniques such as the suture technique, tongue-in-groove, and swinging door were invented to correct caudal septal deviation, but these techniques cannot effectively manage the excess cartilage length, which is the main problem in anteroposterior caudal septal deviation [16].

The C&S technique, which effectively reduces excess cartilage length without affecting the original tip height, was introduced by Jang et al. in 2009 [3]. However, the superposition of the cartilage on the remaining natural curvature in the C&S technique may reduce the cross-sectional area of the nasal cavity in patients with severe caudal septal deviation. To minimize the effect of the overlapping cartilage, complete removal of the deviated portion and end-to-end anastomosis are required. Hosokawa et al. introduced modified technique that connects the cartilage bank to the anterior nasal spine to avoid adding batten grafts, but the risk of pollybeak deformity persists if the cartilage is cut excessively [17]. Jeon et al. devised a triangular excision and submucosal rejoining technique using the natural fracture line formed on the quadrangular cartilage, but it is of limited use when the fracture line does not involve the most-bent portion of the caudal septum [18]. The wedge resection technique used in this study is not only useful for reducing the cartilage length, but also effective in eliminating septal curvature and internal cartilage memory by removing most of the deviated portion of the cartilage. The upper and lower margins of the remaining cartilage are sutured together to reconstruct the attachment, and the increased concern for a weakened L-strut can be alleviated by adopting batten grafts, such as the bioabsorbable mesh used in this study.

Cartilaginous or bony autografts are often used as batten grafts to reinforce the modified septal cartilage. However, autografts large and strong enough to support the deviated septum cannot always be obtained from the patient. Moreover, harvesting autografts can cause loss of tip support [13]. Cartilaginous grafts are more likely to cause saddle nose or external deformity due to their inability to bear nasal weight, and bony grafts need drilling to be sutured on the residual cartilage, which is a bothersome procedure for surgeons [2, 5]. Thus, allografts that can be surgically manipulated and have sufficient strength to withstand nasal weight are needed to replace autografts.

In 2016, Kang et al. implanted a PDS-like bioabsorbable plate as a batten graft for caudal septal deviation, and no major complications were reported in the enrolled patients [1]. However, in our experience, the PDS-like plate is not strong enough to support the modified septum. Other alloplastic implants have been used for the reconstruction of the septum, but most of the materials have major drawbacks in terms of ease of surgical manipulation [10].

PCL has been approved by the U.S. Food and Drug Administration for use in the human body, specifically as a drug delivery device, suture, or adhesion barrier. In a previous animal study, a 3-D printed PCL mesh showed efficacy in maintaining tip refinement without material-related complications, and its micropores allowed for fibroblastic growth and fibrovascular permeation from the surrounding host tissue [13]. The 3-D printed PCL mesh is more affordable and allows better surgical manipulation than other biodegradable plates. In addition, its porous structure contributes to the reconstruction of the damaged septum by allowing migration of the nearby normal tissue, which helps enhance the stability of the modified septum. The compressive stiffness of PCL implants is similar to that of cartilage, which means that the mechanical properties of the PCL mesh correspond with those of the cartilage [19, 20]. Additionally, the 0.5-mm-thick mesh used in this study did not reduce the cross-sectional area of the nasal cavity, preventing possible secondary nasal obstruction caused by the batten graft. To our knowledge, there is no marketed PCL mesh for reconstructive surgery or graft in USA or Europe so far. However, the research is ongoing for its use on stress urine incontinence or pelvic prolapse with satisfying results, so we expect the PCL mesh soon to be available worldwide [21, 22].

A previous study evaluating the mechanical properties of PCL mesh also reported surgical outcomes in caudal septal deviation [10]. However, the techniques applied to the caudal septum before implanting the mesh were heterogeneous, and the overall severity of deviation before surgery could not be assessed. Most of the patients enrolled in the present study had severe caudal septal deviation almost reaching the lateral nasal wall (Fig. 4), and caudal deviations were mostly modified using the wedge resection technique (Table 2). Moreover, significant symptomatic improvements were noted, and postoperative endoscopy confirmed a straight septum in most of the patients without any complications (Figs. 2, 3, 4). None of the patients presented with re-deviation or external deformity of the nose during the follow-up period of up to 1 year after the surgery, which demonstrates the long-term stability of the PCL mesh. In addition, no inflammatory signs or foreign body reactions to the PCL mesh, which is known to be degraded in the body within 2–3 years after implantation, were noted during the observation period, proving its biocompatibility in the human body. Meanwhile, patient no. 6 complained of persistent nasal obstruction after surgery, even though postoperative endoscopy confirmed a straight septum and no visible anatomic cause for obstruction could be identified.