Work

Lateral Mucosal Flap With Steroid‐Eluting Implant in Revision Draf Type III Frontal Sinus Surgery

Year: 2026

Type: article

Abstract: This technical note introduces a novel endoscopic strategy that integrates a laterally based endonasal mucosal flap with a bioabsorbable steroid-eluting implant to prevent restenosis following revision of Draf type III frontal sinus surgery. The vascularized flap is stabilized and maintained in close apposition to the underlying bone by a self-expanding bioabsorbable stent, which simultaneously provides sustained local corticosteroid delivery to reduce postoperative inflammation. By combining mechanical stabilization with targeted anti-inflammatory therapy, this technique represents a potentially innovative solution to promote mucosalization and maintain patency of the frontal neo-ostium in complex revision cases. Draf type III frontal sinusotomy, also known as the Modified Lothrop Procedure (MLP), is an endoscopic-assisted endonasal technique that entails removal of the frontal beak, the floor of both frontal sinuses, the intersinus frontal septum, and the adjacent superior portion of the nasal septum. The goal is to create the largest possible drainage pathway, extending from one lamina papyracea to the contralateral side. Indications for such an extensive procedure are heterogeneous in the literature and include refractory frontal sinus disorders such as severe chronic recalcitrant sinusitis and frontal sinus mucocele, as well as benign and malignant sinonasal tumors [1]. However, partial stenosis or complete closure of the frontal neo-ostium occurs in 5%–32% of cases, posing a significant concern for clinicians [2]. The main factors contributing to restenosis, even after a wide drainage pathway as achieved with Draf type III, are extensive mucosal stripping with large areas of exposed bone, postoperative inflammatory reaction with neo-osteogenesis, scar tissue formation, and unfavorable anatomical conditions of the frontal recess (e.g., reduced antero-posterior diameter) [3]. Several techniques have been proposed to prevent restenosis after Draf type III, including pedicled or random local flaps, free mucosal grafts, and laterally based endonasal flaps [3, 4]. However, most of these techniques are primarily described in primary surgical settings and are often not feasible in revision cases due to prior harvesting, extensive mucosal damage, or lack of native healthy mucosa. In addition to this, steroid-eluting sinus stents have been introduced as a device to maintain postoperative patency of sinus openings while simultaneously delivering topical corticosteroids into the sinonasal cavity. This anti-inflammatory action reduces, theoretically, scar tissue formation and neo-osteogenesis, thus improving both patients' symptoms and quality of life [5]. The aim of this study is to describe a novel lateral-based endonasal mucosal flap, stabilized by a steroid-eluting stent, for revision of Draf type III frontal sinusotomy. A retrospective observational study was conducted at the Department of Otorhinolaryngology, Sant'Anna Hospital, University of Insubria, Como, Italy. Clinical databases were reviewed to identify patients undergoing revision of Draf type III frontal sinusotomy between November 2023 and November 2024. Inclusion criteria were patients treated with a lateral-based flap and steroid-eluting implant (PROPEL mini, Medtronic, Jacksonville, USA). The study adhered to the ethical standards of the 1964 Declaration of Helsinki (amended in 2011) and was approved by the Local Ethics Committee of ASST Lariana (No. 212/2024), Italy. Informed consent was obtained from all patients. The surgical technique is shown in Video S1 and summarized below (Figure 1). Surgery is performed under general anesthesia with the patient in a supine reverse Trendelenburg position. The nasal cavities are packed with neurosurgical patties soaked in 0.05%–0.2% oxymetazoline and adrenaline (1:100,000–1:200,000), depending on age and comorbidities, for 5–10 min. Both 0° and 45° endoscopes (4 mm, Karl Storz, Tuttlingen, Germany) are used. Two horizontal mucosal incisions, an anterior and a posterior, at a distance of 15 mm from each other, are made on the neo-mucosa in front of the anterior margin of the previous Draf type III sinusotomy, and prolonged laterally along the course of the frontal process of both maxillary bones until the height of the inferior turbinate is reached (Figure 2A). This flap is elevated from one side, leaving the pedicle attached contralaterally. Since this is a random-vascularized flap, a broad pedicle should be preserved. The lateral-based U-shaped flap is temporarily stored in the ipsilateral maxillary sinus during the revision procedure. The newly formed bone obstructing the frontal drainage is removed with a Kerrison punch and drilled out using straight and angled 4 mm diamond burrs (30 K high-speed; Medtronic, Jacksonville, USA) to re-establish patency (Figure 2B). Once the neo-osteogenesis is drilled away and residual inflamed mucosa excised, the flap is repositioned upward to resurface the anterior circumference of the neo-ostium, covering the exposed bone and thereby reducing scar deposition and circular restenosis risk (Figure 2C). Finally, the steroid-eluting sinus stent (PROPEL mini) is deployed (Figure 3A,B). In this setting, the device has a dual role [1] sustained steroid release to mitigate postoperative inflammation and edema, and [2] mechanical support to secure the flap in place and prevent displacement. Nasal packing is applied for one day to minimize bleeding and prevent nose blowing. The first endoscopic debridement under local anesthesia is performed 48 h postoperatively to inspect flap and stent positioning and clear blood clots/fibrin. Further debridement procedures are scheduled every 15 days until 45–60 days, promoting mucosal healing and maintaining drainage patency (Figure 4A). By this time, the stent is fully resorbed, the mucosa healed, and the flap integrated (Figure 4B). Subsequent follow-up is tailored to the underlying pathology. Three patients met the inclusion criteria. Clinical data are summarized in Table 1. All patients presented with frontal headache and nasal obstruction preoperatively, and all had previously undergone at least one Draf type III procedure. Diagnosis of frontal restenosis was confirmed in the outpatient clinic via nasal endoscopy and maxillofacial CT scan. All underwent revision Draf type III with a lateral-based flap and steroid-eluting stent. Surgical time ranged from 178 to 245 min (Table 1). No intra- or postoperative complications were encountered. After a follow-up ranging from 9 to 21 months (Table 1), all patients reported complete resolution of preoperative symptoms. One patient developed mild granulation tissue at the anterior stent site, which resolved spontaneously after stent resorption. Another patient experienced purulent discharge and mucosal edema with reduced neo-ostium diameter due to Haemophilus influenzae and Staphylococcus aureus infection, which was successfully treated with oral and topical antibiotics. At final follow-up, no cases of restenosis of the frontal neo-ostium were observed. The Draf type III procedure is a well-established technique for managing extensive frontal sinus disease [1]. Despite providing the widest possible endonasal drainage pathway, restenosis remains a significant challenge. Several strategies have been proposed to reduce this adverse event, including: [1] limiting excessive drilling, as overheating of bone can induce inflammation and stimulate neo-osteogenesis; [2] using systemic and topical antibiotics to minimize postoperative infection, inflammation, and edema; and [3] avoiding leaving exposed bone, since this promotes scar tissue deposition and neo-osteogenesis. To address the latter, several pedicled flaps, including laterally based endonasal flaps, have been described to resurface exposed bone and enhance mucosal healing [3, 4]. In revision cases, however, classical flaps are often not feasible because the superior nasal septum and lateral nasal wall mucosa have already been resected and replaced by cicatricial neo-mucosa. Free mucosal grafts harvested from the nasal floor or turbinates may be attempted, but their lack of vascularization results in unpredictable integration and variable outcomes. In this challenging scenario, the novel laterally-based pedicled flap offers a reliable alternative. Although its vascularization is less solid than that of primary flaps, since it is derived from scarred neo-mucosa formed after the previous surgery, it theoretically remains more effective than free grafts and provides a vascularized surface that promotes mucosal healing. By covering exposed bone, this flap also limits the osteitic process that would otherwise serve as a stimulus for inflammation, neo-osteogenesis, and fibrosis. The possibility to place a vascularized flap even in revision cases is therefore of high clinical relevance, as concentric fibrosis is one of the main factors leading to failure after Draf type III. Another strategy to limit restenosis is stenting. Traditional silicone stents have long been used but are associated with drawbacks such as pressure ulcer with local necrosis, impaired ventilation, granulation tissue, edema, and early infection. More recently, bioabsorbable steroid-eluting stents have been developed, representing an important technological advance [5]. These devices are self-expanding, resorb within 4–6 weeks, and thanks to their lightweight, non-obstructive design, might create more favorable conditions for mucosal healing, with restoration of sinus ventilation and mucociliary clearance over time. Moreover, the slow release of topical corticosteroids reduces postoperative inflammation and edema, creating more favorable conditions for mucosal healing. In our experience, the synergistic use of the lateral-based flap and steroid-eluting stent enhances each other's benefits. The flap provides coverage of exposed bone and helps prevent scarring, while the steroid-eluting stent reduces postoperative inflammation through corticosteroid delivery and provides temporary positional support during the intraoperative and very early postoperative phase, helping to minimize flap displacement while inflammation and edema subside. This combined approach proved safe and effective in our series, promoting mucosal healing and maintaining frontal neo-ostium patency in all patients. Such results are encouraging, especially in the setting of revision frontal sinus surgery, which is notoriously associated with high failure rates and repeated surgical interventions over time. The main limitations of this study include the small and heterogeneous population of patients, lack of a control group, and relatively short follow-up. Nevertheless, the positive outcomes suggest that this combined strategy may represent a valuable addition to the armamentarium of rhinologists dealing with complex frontal sinus revisions. Larger prospective studies with longer follow-up are warranted to confirm these findings and to better define the indications for intra-frontal steroid-eluting implants. Revision frontal sinus surgery after Draf type III restenosis remains a major challenge for rhinologists. This study suggests that the combined use of a novel lateral-based flap and a steroid-eluting stent is a safe and effective strategy to promote mucosal healing and prevent restenosis of the frontal median drainage. Further research with larger cohorts is required to validate the reproducibility and long-term efficacy of this combined approach. Mario Turri-Zanoni made substantial contributions to conception, design and acquisition of data, drafted the article, revised it critically for important intellectual content, gave final approval of the version to be published, and agreed to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. Gloria Schiavo and Andrea Vinciguerra made substantial contributions to conception of the article and revised it critically for important intellectual content, gave final approval of the version to be published, and agreed to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. Macro Valentini, Federico Russo and Paolo Battaglia made substantial contributions to conception of the data, revised it critically for important intellectual content, gave final approval of the version to be published, and agreed to be accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved. Open access publishing facilitated by Azienda Socio Sanitaria Territoriale Lariana, as part of the Wiley – SBBL agreement. The authors have nothing to report. The authors have nothing to report. The authors declare no conflicts of interest. Data sharing not applicable to this article as no datasets were generated or analysed during the current study. Video S1: Representative clinical case illustrating the step-by-step endoscopic execution of the lateral mucosal flap with steroid-eluting implant during revision Draf type III frontal sinus surgery (duration: 1:51 min). The video presents the main intraoperative phases, including mucosal incision, flap elevation, drilling of neo-osteogenesis, flap repositioning, and deployment of the PROPEL mini stent. The full English transcript of the narration is available as Supporting Information. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.

Source: The Laryngoscope

DOI: 10.1002/lary.70520