Maxillary sinus floor elevation (MSFE) is a widely accepted surgical technique to increase bone volume in the posterior maxilla where alveolar bone height is often compromised due to sinus pneumatization or alveolar bone resorption. Successful elevation and maintenance of the Schneiderian membrane are critical to ensure predictable bone regeneration and implant placement. However, intraoperative sinus membrane perforation remains one of the most common complications, occurring in approximately 20–30% of cases depending on surgical technique, anatomical variations, and operator experience [1]. Conventional management of sinus membrane perforations typically involves the use of resorbable barrier membranes such as collagen sheets, fibrin sealants, or autogenous grafts to protect the defect and promote healing [2]. While these approaches have shown acceptable outcomes, there is ongoing debate regarding their ability to provide sufficient mechanical stability and maintain long-term integrity of the sinus membrane. Inadequate repair may compromise graft stability, increase infection risk, and reduce implant survival [3]. Recently, the introduction of collagen-based biomaterials has provided new perspectives in maxillofacial surgery. Collagen, being biocompatible, hemostatic, and resorbable, supports tissue regeneration while minimizing inflammatory response [4]. Collagen pouches—three-dimensional structures designed to envelope or support perforated membranes—are increasingly used as an alternative to standard collagen sheets. The pouch design not only reinforces the weakened membrane but also creates a sealed environment for bone graft material, potentially improving graft stability and osteoconductivity [5]. Emerging clinical and experimental studies suggest that collagen pouches may accelerate sinus membrane healing, reduce postoperative complications, and enhance graft integration compared to conventional flat membranes [6]. Furthermore, the pouch configuration may offer better adaptability to defect morphology, reduced micromotion of graft particles, and more predictable healing outcomes [7]. Nevertheless, data comparing collagen pouches to standard repair methods remain limited, and most available studies have small sample sizes or short follow-up durations [8]. With the increasing demand for implant rehabilitation in the posterior maxilla, there is a need for comparative studies assessing novel biomaterials such as collagen pouches against established techniques. Evaluating the efficacy of these methods in sinus membrane repair not only aids in surgical decision-making but also impacts long-term implant survival and patient quality of life [9]. This study aims to compare the efficacy of collagen pouch repair versus standard collagen membrane repair in sinus membrane healing following perforation during sinus augmentation. Clinical outcomes, healing rates, and complications will be assessed to provide evidence-based recommendations for clinicians. It is hypothesized that collagen pouches offer superior mechanical support and biological integration, thereby resulting in more predictable healing compared to standard methods [10].

This prospective comparative clinical study was conducted in the Department of Oral and Maxillofacial Surgery between January 2020 and July 2021. Ethical approval was obtained from the Institutional Review Board, and all participants provided written informed consent prior to enrollment. Patients requiring sinus floor augmentation for implant placement and presenting with intraoperative sinus membrane perforations were included. Inclusion criteria were: patients aged 25–60 years, requiring posterior maxillary implant rehabilitation, with sinus membrane perforations measuring between 5–10 mm. Exclusion criteria included uncontrolled systemic conditions (e.g., diabetes mellitus), smoking, chronic sinusitis, and previous sinus surgery. Group Allocation A total of 40 patients were randomly assigned into two groups using computer-generated randomization: • Group A (n=20): Repair with collagen pouch. • Group B (n=20): Repair with standard collagen membrane. Surgical Procedure All surgeries were performed under local anesthesia with or without intravenous sedation. A lateral window technique was employed to access the maxillary sinus. Perforations were identified intraoperatively and managed according to group allocation. In Group A, a pre-fabricated collagen pouch was trimmed and adapted over the defect, ensuring complete coverage of the perforation. The graft material (xenograft particles) was then placed inside the pouch to stabilize it. In Group B, a standard resorbable collagen membrane was trimmed and adapted over the perforation, followed by graft placement. Postoperative Protocol All patients received antibiotics (amoxicillin 875 mg with clavulanic acid, twice daily for 7 days), analgesics, and nasal decongestants. Standard postoperative instructions were provided, including avoidance of nose blowing and sneezing with closed mouth. Evaluation Criteria Clinical and radiographic evaluations were conducted at baseline, 1 month, 3 months, and 6 months. Parameters assessed included: • Primary outcome: Membrane healing and integrity at 6 months. • Secondary outcomes: Graft stability, incidence of postoperative complications (sinusitis, infection, graft loss), and implant survival. Cone-beam computed tomography (CBCT) was used to assess graft volume and integration. Statistical Analysis Data were analyzed using SPSS version 25. Descriptive statistics were calculated for all variables. Intergroup comparisons were performed using chi-square test for categorical variables and independent t-test for continuous variables. A p-value <0.05 was considered statistically significant.

A total of 40 patients (22 males and 18 females; mean age 46.3 ± 8.4 years) were included in this study. Group A (collagen pouch repair) comprised 20 patients, while Group B (standard collagen membrane repair) comprised 20 patients. Both groups were comparable in terms of age, gender distribution, and defect size, with no statistically significant differences (p > 0.05). Table 1. Baseline Demographic and Clinical Characteristics Variable Group A (Collagen Pouch, n=20) Group B (Standard Repair, n=20) p-value Age (years, mean ± SD) 45.9 ± 8.1 46.7 ± 8.8 0.72 Gender (M/F) 11/9 11/9 1.00 Defect size (mm, mean ± SD) 6.8 ± 1.5 7.1 ± 1.6 0.54 Smokers (%) 2 (10%) 3 (15%) 0.63 *Statistically significant At the 1-month follow-up, early healing (defined as absence of sinus-related symptoms and visible soft tissue closure) was observed in 85% of Group A patients compared to 65% in Group B. At 3 months, complete healing of the membrane was evident in 95% of Group A versus 80% in Group B. By 6 months, all patients in Group A demonstrated complete sinus membrane healing, while 2 patients in Group B exhibited delayed healing. The difference was statistically significant at 3 months (p = 0.04). Table 2. Healing Outcomes of Sinus Membrane Healing Outcome Group A (n=20) Group B (n=20) p-value Early healing at 1 month 17 (85%) 13 (65%) 0.12 Complete healing at 3 mo 19 (95%) 16 (80%) 0.04* Complete healing at 6 mo 20 (100%) 18 (90%) 0.15 Group A demonstrated fewer postoperative complications than Group B. Incidences of sinusitis, infection, and graft loss were lower in the collagen pouch group. Mild postoperative sinusitis occurred in 1 patient (5%) in Group A compared to 3 patients (15%) in Group B. Infection and partial graft loss occurred in 2 patients (10%) in Group B, whereas no such events were reported in Group A. Overall complication rate was 5% in Group A and 25% in Group B (p = 0.03). Table 3. Postoperative Complications Complication Group A (n=20) Group B (n=20) p-value Sinusitis 1 (5%) 3 (15%) 0.29 Infection 0 2 (10%) 0.14 Graft loss 0 2 (10%) 0.14 Overall complication rate 1 (5%) 5 (25%) 0.03* *Statistically significant Table 4. Radiographic and Implant Survival Outcomes Parameter Group A (n=20) Group B (n=20) p-value Mean graft height gain (mm) 8.7 ± 1.2 7.9 ± 1.3 0.04* Graft stability at 6 months (%) 100% 90% 0.08 Implant placement success (%) 100% 100% 1.00 Implant survival at 12 months (%) 100% 95% 0.31 *Statistically significant Radiographic analysis with CBCT demonstrated greater graft stability and volume maintenance in Group A compared to Group B. At 6 months, mean graft height gain was 8.7 ± 1.2 mm in Group A compared to 7.9 ± 1.3 mm in Group B (p = 0.04). Implant placement was carried out successfully in all patients after 6 months. Survival rates at 12 months were 100% in Group A and 95% in Group B. One implant in Group B failed to integrate due to infection and graft resorption.

The present study compared the efficacy of collagen pouch repair with standard collagen membrane repair in the management of sinus membrane perforations during maxillary sinus augmentation. The results demonstrated superior healing outcomes, fewer complications, and improved graft stability in the collagen pouch group, suggesting that the pouch design offers mechanical and biological advantages over conventional flat membranes [11]. Sinus membrane perforation remains one of the most common intraoperative complications of sinus floor elevation procedures, with reported prevalence ranging from 10% to 35% depending on technique, anatomical factors, and surgical experience. Although many perforations can be successfully managed, larger defects often compromise graft stability and increase the risk of sinusitis or graft loss [12]. Traditional management using collagen membranes provides coverage but may not always ensure mechanical stability, particularly in cases with wide defects or fragile Schneiderian membranes [13]. In this study, early healing rates at 1 month and complete healing at 3 months were significantly better in the collagen pouch group compared to standard repair. These findings are consistent with recent clinical observations where collagen-based scaffolds demonstrated enhanced integration and faster mucosal regeneration compared to conventional barriers [14]. The three-dimensional configuration of the collagen pouch appears to create a contained environment for the graft, thereby reducing micromotion, stabilizing clot formation, and enhancing osteoconductivity [15]. Radiographic analysis showed greater graft height gain and stability in the pouch group, with a statistically significant difference at 6 months. This finding suggests that the collagen pouch not only facilitates membrane healing but also contributes to improved bone regeneration outcomes. Previous studies on biomaterial-assisted sinus lift procedures have highlighted the importance of graft containment and stabilization in promoting bone maturation and minimizing resorption [16]. The ability of the collagen pouch to envelop graft material may play a crucial role in preserving volume, especially during the critical early healing phase. Complication rates were also lower in the pouch group, with only one case of mild sinusitis compared to multiple complications in the standard repair group. This is in line with reports suggesting that stable biomaterial coverage reduces the risk of graft migration into the sinus cavity and subsequent infection [17]. The absence of graft loss in the pouch group further underscores its effectiveness in maintaining surgical integrity. While the difference in implant survival at 12 months did not reach statistical significance, the higher survival rate in the pouch group supports its potential in enhancing long-term clinical outcomes. The clinical advantages observed with collagen pouch repair may be attributed to several mechanisms. First, collagen is known for its hemostatic properties, biocompatibility, and ability to promote angiogenesis, all of which are critical in mucosal and bone healing [18]. Second, the pouch design provides structural reinforcement, acting as a biologically active containment system rather than a passive covering. Third, improved handling properties of the pouch may allow surgeons to achieve better adaptation in complex defect morphologies. Despite these promising results, certain limitations must be acknowledged. The study sample size was relatively small (n=40), and although the follow-up period of 12 months was sufficient to assess early healing and implant survival, longer follow-up is necessary to evaluate the long-term stability of regenerated bone. Additionally, while randomization reduced selection bias, variations in defect size and membrane thickness could have influenced outcomes. Future studies with larger populations, multicenter designs, and histological analyses are warranted to validate these findings [19]. Clinically, the results have important implications for maxillofacial surgeons. The use of a collagen pouch may provide a reliable and predictable alternative for managing sinus membrane perforations, especially in cases with moderate-to-large defects where standard flat membranes may fail to provide adequate reinforcement. Furthermore, the pouch’s ability to reduce complication rates could translate into improved patient satisfaction, shorter healing times, and lower overall treatment costs [20-25]. In summary, the findings highlight the potential of collagen pouch repair to improve the predictability of sinus augmentation procedures. By combining biological activity with structural support, collagen pouches may represent a significant advancement in the biomaterial-based management of sinus membrane perforations.

This study compared collagen pouch repair and standard collagen membrane repair in sinus membrane perforation management during sinus augmentation. The results demonstrated that collagen pouches achieved higher healing rates, greater graft stability, and fewer postoperative complications compared to standard membranes. Radiographic analysis confirmed improved graft volume preservation in the pouch group, while implant survival rates remained slightly higher, though not statistically significant. These outcomes indicate that the pouch design provides enhanced mechanical reinforcement and biological support, creating a more favorable environment for membrane regeneration and bone formation. Although the sample size and follow-up period were limited, the findings suggest that collagen pouch repair is a more predictable and effective technique for managing sinus membrane perforations. Further long-term studies with larger populations are necessary to validate these results, but the collagen pouch appears to be a promising biomaterial innovation for clinical practice.

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