Coated poly-4-hydroxybutyrate (Phasix ST™) mesh is safe and effective for hiatal hernia repair: our institutional experience and review of the literature.

BACKGROUND: Poly-4-hydroxybutyrate (P4HB) is a bioabsorbable mesh with a non-adhesive coating on one side that is being used to reinforce the hiatus during hiatal hernia repair; however, there is limited data regarding its use. The aim of this study was to investigate outcomes after hiatal hernia repair using this mesh at our institution and through a review of the literature. METHODS: An institutional review board-approved prospective database was retrospectively reviewed for all patients undergoing hiatal hernia repair from April 2018 to December 2022. A systematic review with meta-analysis was conducted to evaluate outcomes using P4HB coated mesh. RESULTS: In our institutional cohort, there were 230 patients (59 males; 171 females) with a mean follow-up of 20 ± 14.6 months. No mesh-related complications occurred. Hernia recurrence was diagnosed in 11 patients (4.8%) with a median time to recurrence of 16 months. In the systematic review, 4 studies with 221 patients (76 males; 145 females) were included. Median follow-up ranged from 12 to 27 months. Recurrence rate in these studies was reported from 0 to 8.8%, with a total of 12 recurrences identified. Like our institutional cohort, no mesh-related complications were reported. After our recurrences were combined with those from the systematic review, a total of 23 recurrences were included in the meta-analysis. Our meta-analysis revealed a low recurrence rate following hiatal hernia repair with P4HB coated mesh (incidence rate per 100 person-years, 2.82; 95% confidence interval, 1.60, 4.04). CONCLUSION: P4HB coated mesh is safe and effective for hiatal hernia repairs.

Patient-tailored algorithm for laparoscopic cruroplasty standardization: comparison with hiatal surface area and medium-term outcomes.

BACKGROUND: Different methods have been described for laparoscopic hiatoplasty and hiatus hernia (HH) repair. All techniques are not standardized and the choice to reinforce or not the hiatus with a mesh is left to the operating surgeon's preference. Hiatal surface area (HSA) has been described as an attempt at standardization; in case the area is > 4 cm2, a mesh is used to reinforce the repair. OBJECTIVE: The aim of this study was to describe a new patient-tailored algorithm (PTA), compare its performance in predicting crura mesh buttressing to HSA, and analyze outcomes. METHODS: Retrospective, single-center, descriptive study (September 2018-September 2021). Adult patients (≥ 18 years old) who underwent laparoscopic HH repair. Outcomes and quality of life measured with the disease-specific gastroesophageal reflux disease health-related quality of life (GERD-HRQL) and reflux symptom index (RSI) were analyzed. RESULTS: Fifty patients that underwent laparoscopic hiatoplasty and Toupet fundoplication were included. The median age was 61 years (range 32-83) and the median BMI was 26.7 (range 17-36). According to the PTA, 27 patients (54%) underwent simple suture repair while crural mesh buttressing with Phasix-ST® was used in 23 (46%). According to the HSA, the median hiatus area was 4.7 cm2 while 26 patients had an HSA greater than 4 cm2. The overall concordance rate between PTA and HSA was 94% (47/50). The median hospital stay was 1.9 days (range 1-8) and the 90-day complication rate was 4%. The median follow-up was 18.6 months (range 1-35). Hernia recurrence was diagnosed in 6%. Postoperative dysphagia occurred in one patient (2%). The GERD-HRQL (p < 0.001) and RSI (p = 0.001) were significantly improved. CONCLUSIONS: The application of PTA for cruroplasty standardization in the setting of HH repair seems effective. While concordance with HSA is high, the PTA seems easier and promptly available in the operative theater with a potential increase in procedure standardization, reproducibility, and teaching.

Onlay Poly-4-Hydroxybutyrate (P4HB) Mesh for Complex Hernia: Early Clinical and Patient Reported Outcomes.

BACKGROUND: While mesh re-enforcement and advanced surgical techniques are cornerstones of complex ventral hernia repair (CVHR), the risk of complications and recurrence is common. We aim to evaluate the efficacy, safety, and patient reported outcomes (PROs) of patients undergoing CVHR with onlay Poly-4-hydroxybutyrate (P4HB). METHODS: Adult (>18 y old) patients undergoing VHR with P4HB (Phasix) in the onlay plane by a single surgeon from 01/2015 to 05/2020 were reviewed. VHR was considered complex if patients had significant co-morbidities, large abdominal wall defects, a history of extensive abdominal surgery, and/or concurrent intra-abdominal pathology. A composite of postoperative outcomes including surgical site occurrences (SSO), surgical site infection (SSI), and surgical site occurrences requiring procedural intervention (SSOpi), as well as PROs as defined by the Abdominal Hernia-Q (AHQ), were analyzed. RESULTS: A total of 51 patients were included with average age and body mass index of 56.4 and 29.9 kg/m2. Median follow up was 20 mo with a hernia recurrence rate of 5.9% (n = 3). 21 patients had an SSO (41.2%), 8 had an SSI (15.7%), and 6 had an SSOpi (11.8%). There was an association with Ventral Hernia Working Group ≥ 2 and development of SSO. There was a significant improvement in overall PROs (P < 0.0001) with no difference in those patients with and without complications (P > 0.05). CONCLUSION: For hernia patients with large defects and complex intra-abdominal pathology, a safe and effective repair is difficult. The use of onlay P4HB was associated with acceptable postoperative outcomes and recurrence rate.

Evaluation of a fully absorbable poly-4-hydroxybutyrate/absorbable barrier composite mesh in a porcine model of ventral hernia repair.

BACKGROUND: The objective of this study was to evaluate the mechanical and histological properties of a fully absorbable poly-4-hydroxybutyrate/absorbable barrier composite mesh (Phasix™ ST) compared to partially absorbable (Ventralight™ ST), fully absorbable (Phasix™), and biologically derived (Strattice™) meshes in a porcine model of ventral hernia repair. METHODS: Bilateral abdominal surgical defects were created in twenty-four Yucatan pigs, repaired with intraperitoneal (Phasix™ ST, Ventralight™ ST) or retromuscular (Phasix™, Strattice™) mesh, and evaluated at 12 and 24 weeks (n = 6 mesh/group/time point). RESULTS: Prior to implantation, Strattice™ demonstrated significantly higher (p < 0.001) strength (636.6 ± 192.1 N) compared to Ventralight™ ST (324.3 ± 37.1 N), Phasix™ ST (206.9 ± 11.3 N), and Phasix™ (200.6 ± 25.2 N). At 12 and 24 weeks, mesh/repair strength was significantly greater than NAW (p < 0.01 in all cases), and no significant changes in strength were observed for any meshes between 12 and 24 weeks (p > 0.05). Phasix™ mesh/repair strength was significantly greater than Strattice™ (p < 0.001) at 12 and 24 weeks, and Ventralight™ ST mesh/repair strength was significantly greater than Phasix™ ST mesh (p < 0.05) at 24 weeks. At 12 and 24 weeks, Phasix™ ST and Ventralight™ ST were associated with mild inflammation and minimal-mild fibrosis/neovascularization, with no significant differences between groups. At both time points, Phasix™ was associated with minimal-mild inflammation/fibrosis and mild neovascularization. Strattice™ was associated with minimal inflammation/fibrosis, with minimal neovascularization at 12 weeks, which increased to mild by 24 weeks. Strattice™ exhibited significantly less neovascularization than Phasix™ at 12 weeks and significantly greater inflammation at 24 weeks due to remodeling. CONCLUSIONS: Phasix™ ST demonstrated mechanical and histological properties comparable to partially absorbable (Ventralight™ ST) and fully resorbable (Phasix™) meshes at 12 and 24 weeks in this model. Data also suggest that fully absorbable meshes with longer-term resorption profiles may provide improved mechanical and histological properties compared to biologically derived scaffolds.

The use of poly-4-hydroxybutyrate (P4HB, Phasix™) mesh in ventral hernia repair: a systematic review and meta-analysis.

PURPOSE/BACKGROUND: Despite the growing use of bioabsorbable mesh in ventral hernia repairs (VHR), the evidence of its impact on patient outcomes remains limited. This study aims to investigate the efficacy and safety profile of poly-4-hydroxybutyrate (P4HB) mesh for ventral hernia repair through a systematic review and meta-analysis. METHODS: A literature search of five databases (PubMed, Embase, Ovid, Medline, and Google Scholar) produced a list of publications that analyzed the use of P4HB mesh in ventral hernia repair in both clean and contaminated cases. The primary postoperative outcomes of hernia recurrence, surgical site infections (SSI), and any complications were analyzed through a pooled meta-analysis. RESULTS: In our systematic review, 21 studies met the inclusion criteria with a total of 1858 patients (933 males and 925 females) and an average age of 56.8 years. The median follow-up ranged from 1.6 to 62.3 months. In our meta-analysis, the use of P4HB mesh in VHR in proportion of events demonstrated a recurrence rate of 9% [6%; 15%], SSI of 10% [6%; 16%] and 35% [9%; 42%] for rate of any complications. Sub-meta-analysis restricted to studies with follow up > 18 months continues to show low rates of recurrence of 9% (95%CI, 4-17%), SSI of 9% (95%CI, 4-16%), and 31% (95%CI, 23-41%) for any complications. CONCLUSION: Our study demonstrates that the use of P4HB mesh is both safe and effective in ventral hernia repairs. When further analyzed past 18 months, the time where P4HB mesh fully resorbs, the rates of hernia recurrence, SSI, and any complications remain low of upwards of 5 years and comparable to the rates seen in synthetic and biologics in similar patient populations.

Medium term (> 12 months) outcomes after laparoscopic hiatal hernia repair without conventional fundoplication using PH4B-mesh implant (Phasix™) in 176 reflux patients: experience and technique.

BACKGROUND: Hiatal mesh repair remains a controversial topic among anti-reflux surgeons. Biosynthetic mesh cruroplasty may prevent early recurrence while avoiding late esophageal erosion and strictures associated with non-resorbable materials. So far, medium-term results on hiatal PH4B (Poly-4-Hydroxybutyrate) mesh repair from high-volume centers are lacking. METHODS: We analyzed the medium-term efficacy and safety of PH4B mesh cruroplasty in 176 consecutive patients (≥ 18 years) with symptomatic hiatal hernias. Treatment failure was defined as the clinical recurrence of reflux symptoms. Patients could choose between mesh augmented hiatal repair (combined with a modified anterior hemifundoplication and fundophrenicopexy), Nissen fundoplication, and magnetic sphincter augmentation at their discretion. We also describe the surgical approach to mesh augmented hiatal repair used at our center. RESULTS: On average, patients were 55 (± 14) years old and followed up for 22 (± 7; sum: 3931) months. Treatment failed in 6/176 (3%, 95% CI: 2-7%) patients. The 24-month Kaplan-Meier failure estimate was 2.8% (95% CI: 0.4-5%). Each centimeter in hernia size increased the risk of failure by 52% (p = 0.02). Heavier patients (BMI > 27) had an 11% higher probability of clinical symptom recurrence (p = 0.03). The dysphagia and bloating/gas rate were 13/176 (7%), each. 8 (5%) patients required endoscopy due to dysphagia but without intervention. No serious complications, including mesh infection and erosion, or fatalities, occurred. CONCLUSION: Augmented PH4B mesh cruroplasty without conventional fundoplication shows excellent intermediate-term results in patients with reflux disease due to hiatal hernia. Around one in thirty patients experience treatment failure within 2 years of surgery. Hernia size and overweight are key determinants of treatment failure.

Long-term results with biosynthetic absorbable P4HB mesh in ventral abdominal wall repair: a multicentre analysis.

BACKGROUND: The aim of this multicentre study was to analyse the outcomes of biosynthetic absorbable poly-4-hydroxybutyrate (P4HB) prosthesis implantation in patients undergoing ventral hernia repair (VHR) in the context of different degrees of contamination. METHODS: From May 2016 to December 2021, a multicentre retrospective analysis of patients who underwent elective or urgent hernia repair with P4HB prosthesis was performed in seven hospitals in Spain and Portugal. Patients with a postoperative follow-up of less than 20 months and those within the theoretical period of prosthesis resorption were excluded from the study. Regarding the degree of contamination, patients were assessed according to the modified Ventral Hernia Working Group (VHWG) classification. Epidemiological data, hernia characteristics, surgical and postoperative variables (Clavien-Dindo classification) of these patients were analyzed. Risk factors related to long-term recurrence were studied by a multivariate analysis. RESULTS: In 236 cases of P4HB prosthesis implantation, repair in cases of Grade 3 was the most frequent (49.1%), followed by Grade 2 in 42.3% of cases and Grade 1 in 8.4%. The most frequent complications were Grade 1, with the majority occurring during the first year. The overall rate of surgical site occurrences (SSO) was 30%. The hernia recurrence rate was 14.4% (n = 34), with a mean postoperative follow-up time of 41 months (22-61). The multivariate analysis showed that the onlay location of the mesh (OR 1.07; CI 1.42-2.70, p = 0.004) was a significant independent risk factor for recurrence. CONCLUSIONS: The use of a P4HB bioresorbable mesh for the VHR with different degrees of contamination leads to favourable results overall, with an acceptable rate of hernia recurrence. The onlay location of the P4HB prosthesis is the main factor in recurrence in both elective and emergency settings.

Characterization of poly-4-hydroxybutyrate mesh for hernia repair applications.

BACKGROUND: Phasix mesh is a fully resorbable implant for soft tissue reconstruction made from knitted poly-4-hydroxybutyrate monofilament fibers. The objectives of this study were to characterize the in vitro and in vivo mechanical and resorption properties of Phasix mesh over time, and to assess the functional performance in a porcine model of abdominal hernia repair. MATERIALS AND METHODS: We evaluated accelerated in vitro degradation of Phasix mesh in 3 mol/L HCl through 120 h incubation. We also evaluated functional performance after repair of a surgically created abdominal hernia defect in a porcine model through 72 wk. Mechanical and molecular weight (MW) properties were fully characterized in both studies over time. RESULTS: Phasix mesh demonstrated a significant reduction in mechanical strength and MW over 120 h in the accelerated degradation in vitro test. In vivo, the Phasix mesh repair demonstrated 80%, 65%, 58%, 37%, and 18% greater strength, compared with native abdominal wall at 8, 16, 32, and 48 wk post-implantation, respectively, and comparable repair strength at 72 wk post-implantation despite a significant reduction in mesh MW over time. CONCLUSIONS: Both in vitro and in vivo data suggest that Phasix mesh provides a durable scaffold for mechanical reinforcement of soft tissue. Furthermore, a Phasix mesh surgical defect repair in a large animal model demonstrated successful transfer of load bearing from the mesh to the repaired abdominal wall, thereby successfully returning the mechanical properties of repaired host tissue to its native state over an extended time period.

Surgical treatment of large and complicated hiatal hernias with the new resorbable mesh with hydrogel barrier (Phasix™ ST): a preliminary study.

Evaluation of the efficacy and safety of the new monofilament fully resorbable mesh with hydrogel barrier (Phasix™ ST), for large and complex hiatal hernia repair. Between December 2017 and December 2020, 60 patients with large or complicated hiatal hernia were treated (40 robotic and 20 laparoscopic procedures). The mesh was placed after primary closure of the hiatal defect, in an onlay fashion around the esophagus, followed by 360o fundoplication. Follow-up at 3, 6, 12, 18, 24 months from intervention included clinical evaluation and upper GI endoscopy. In cases of recurrence, radiologic survey and manometry were utilized. There were no conversions to open repair or significant postoperative incidents. Over a median follow-up of 21 months (range 3-36), no recurrences or mesh related complications were observed. From our early experience, Phasix™ ST mesh seems to be safe and effective for the reinforcement of crural defects in large and complex hiatal hernia.

Fully resorbable poly-4-hydroxybutyrate (P4HB) mesh for soft tissue repair and reconstruction: A scoping review.

Background: Poly-4-hydroxybutyrate (P4HB) is a fully resorbable, biologically-produced polymer with a strength and flexibility comparable to permanent synthetic polymers. The objective was to identify/summarize all peer-reviewed publications involving P4HB mesh. Methods: A scoping review was conducted within PubMed and included articles published through October 2022. Results: A total of n = 79 studies were identified (n = 12 in vitro/bench; n = 14 preclinical; n = 6 commentaries; n = 50 clinical). Of the clinical studies, n = 40 reported results applicable to hernia and n = 10 to plastic/reconstructive surgery and involved patients of all Centers for Disease Control (CDC) wound classes and Ventral Hernia Working Group (VHWG) grades. Conclusion: P4HB mesh provides long-term hernia repair strength and exhibits promising clinical outcomes beyond its resorption period. Future studies should include randomized controlled trials comparing P4HB to other biomaterials, as well as optimal patient selection, operative technique, long-term outcomes, minimization of potential mesh-related complications, and potential contraindications/complications for P4HB in hernia/abdominal wall reconstruction.

Shifting the Goalpost in Ventral Hernia Care: 5-year Outcomes after Ventral Hernia Repair with Poly-4-hydroxybutyrate Mesh.

PURPOSE: Ventral hernia repair (VHR) can be augmented with biosynthetic poly-4-hydroxybutryate mesh (P4HB). Long-term outcomes, including quality of life outcomes, after VHR with P4HB mesh are not well established. Our study sought to assess these outcomes 5 years after repair. METHODS: Patients who received VHR using P4HB by the senior author between 01/2015 and 09/2017 were retrospectively identified. Patients were prospectively interviewed for quality of life assessment using the Hernia-Related Quality-of-Life Survey (HerQLes) and Abdominal Hernia-Q (AHQ) and screened for recurrence. Those who screened positive were asked to follow up in clinic to confirm recurrence. Both 5-year quality of life and recurrence were univariately assessed with patient and operative factors. RESULTS: 51 patients met inclusion criteria. 43 patients completed 5-year quality of life assessment (84.3% response rate). Quality of life scores at all postoperative time periods were greater than preoperative scores. Further, quality of life at 5 years is greater than that assessed 0-2 years following VHR. Most patients achieve their best quality of life in the 5-year time period. Thirty-five patients had clinical follow-up in the 5-year time period, 7 experienced recurrences (20% recurrence rate). There was no difference in 5-year quality of life assessment between those who had a recurrence and those who did not. CONCLUSION: Patient quality of life following VHR with P4HB improves immediately and continues to improve 5 years following repair. There are no differences in quality of life with onset of recurrence. Quality of life should be the primary outcome of success in VHR.

Mechanical and Histological Characteristics of Phasix™ ST Mesh in a Porcine Model of Hernia Repair.

PURPOSE: The objective of this study was to determine mechanical and histological properties of Phasix™ ST Mesh in various defect sizes and characterize the tissue replacing Phasix™ ST Mesh in a porcine model of ventral hernia repair. METHODS: Simulated hernia defects were surgically created in the midline of twenty-four (n = 24) Yucatan pigs. Treatment groups included 8 cm defect sutured closed (buttress) and unclosed 4 cm and 8 cm defect groups. Phasix™ ST Mesh (15 cm diameter circle) was implanted laparoscopically and fixated circumferentially with SorbaFix™ Absorbable Fixation System fasteners. The repair sites underwent mechanical, molecular weight, and histological evaluation at 48 and 72 weeks postimplantation. RESULTS: Mechanical testing of Phasix™ ST Mesh-repaired sites revealed similar strengths at both time points for all three repair types, p > 0.05 in all cases (48 weeks: 142.4 ± 6.0 N, 142.3 ± 16.5 N, and 168.8 ± 38.5 N; 72 weeks: 110.0 ± 18.3 N, 138.6 ± 42.2 N, and 160.6 ± 42.0 N for 4 cm defect, 8 cm defect, and 8 cm buttress, respectively. mean ± SEM) No significant differences were observed over time except at 72 weeks postimplantation when the 4 cm defect group exhibited significantly lower strength than the T0 strength of Phasix™ ST Mesh (204.6 ± 5.0 N, p < 0.05). The molecular weight of Phasix™ ST Mesh decreased over time, regardless of repair type. Histological analysis showed comparable mature collagen/fibrovascular tissue around and within the Phasix™ ST Mesh interstices, including the segment of mesh overlying the defect. CONCLUSION: Phasix™ ST Mesh-repaired sites exhibited similar mechanical strengths and histological properties across all defect sizes in this porcine model.

Outcomes of mid-term and long-term degradable biosynthetic meshes in single-stage open complex abdominal wall reconstruction.

OBJECTIVE: To assess clinical outcomes in patients that underwent open single-stage complex abdominal wall reconstruction (CAWR) with biosynthetic mesh. METHODS: Retrospective observational study of two prospectively registered series of consecutive patients undergoing CAWR with either long-term degradable (LTD) Phasix™ or mid-term degradable (MTD) BIO-A® biosynthetic mesh in a single institution between June 2016 and December 2019. RESULTS: From 169 patients with CAWR, 70 consecutive patients were identified who underwent CAWR with either LTD or MTD biosynthetic mesh. More than 85% of patients had an incisional hernia that could be classified as moderately complex to major complex due to a previous wound infection (67%), one or more complicating comorbidities (87.1%), one or more complicating hernia characteristics (75.7%) or contaminated or dirty defects (37.1%). Concomitant component separation was performed in 43 of 70 patients (61.4%). Overall surgical site infection (SSI) rate in these CAWR patients was 45.7%. Seventeen of 70 patients (24.3%) had computed tomography (CT) - and culture-confirmed SSI in direct contact of mesh, suspicious of mesh infection. Mesh removal for persistent local infection occurred in 10% (7 of 70) after a median of 229 days since surgery. Salvage rate of mesh after direct contact with infection was 58.8%. All removed meshes were in the LTD group. Seven patients (10%) had a recurrence; four patients in the LTD group (10%) had a recurrence at a median follow-up of 35 months and three patients in the MTD group (10%) at a median follow-up of 11 months. Three of the seven recurrences occurred in patients with SSI in persistent and direct contact with mesh. CONCLUSIONS: Comorbid patients undergoing open complex abdominal wall reconstruction are at high risk of postoperative wound complications regardless of which type of biosynthetic mesh is used. When in persistent and direct contact with infection, long-term biodegradable biosynthetic meshes may need to be removed, whereas mid-term biodegradable biosynthetic meshes can be salvaged.

A Novel Use of Fully Absorbable PhasixTM Mesh for Laparoscopic Inguinal Hernia Repair.

BACKGROUND AND OBJECTIVES: An inguinal hernia is usually repaired with synthetic nonabsorbable mesh, resulting in collagen formation, chronic inflammation, and fibrosis, with significantly reduced hernia recurrence. However, chronic pain may affect the quality of life. Poly-4-hydroxybutyrate (P4HB) mesh was introduced to minimize complications, and starts to degrade in 12-18 months. This study assesses the consequences and results of patients undergoing transabdominal preperitoneal (TAPP) inguinal hernia repair using P4HB mesh (PhasixTM, C.R. Bard Inc., Murray Hill, NJ, USA). METHODS: We performed a pilot study of laparoscopic TAPP repair for inguinal hernias using P4HB mesh in 15 patients (14 male and one female) with an average age of 55.8 y, and an average body mass index of 27.4 kg/m2. We assessed the recurrence rate and patients' chronic pain for 30 months, with institutional review board approval (E-19-3735). The study was conducted from January 2016 to July 2017 in Medical City, King Saud University. We measured postoperative pain, reactions, mesh sensation, discomfort, and recurrence. RESULTS: In 15 patients, we encountered no recurrence or mesh sensation, except in one patient, who experienced mild chronic inguinal pain for one year, without activity restrictions. CONCLUSION: Laparoscopic TAPP inguinal hernia repair using P4HB mesh is safe for combined, direct (medial), and indirect (lateral) inguinal hernia, with no recurrence. P4HB absorbable mesh caused less chronic pain and discomfort. Longer follow-up, more patients and 15 patients repaired using synthetic mesh are necessary to assess the utility of P4HB for inguinal hernia repair globally.

Characterization of host response, resorption, and strength properties, and performance in the presence of bacteria for fully absorbable biomaterials for soft tissue repair.

PURPOSE: The objective was to evaluate the host response, resorption, and strength properties, and to assess the performance in the presence of bacteria for Phasix™ Mesh (Phasix™) and Gore® Bio-A® Tissue Reinforcement (Bio-A®) in preclinical models. METHODS: In a rat model, one mesh (2 × 2 cm) was implanted subcutaneously in n = 60 rats. Animals were euthanized after 2, 4, 8, 12, 16, or 24 weeks (n = 5/mesh/time point), and implant sites were assessed for host inflammatory response and overall fibrotic repair thickness. In a rabbit model, meshes (3.8 cm diameter) were bilaterally implanted in subcutaneous pockets in n = 20 rabbits (n = 10 rabbits/mesh) and inoculated with 108 CFU clinically isolated methicillin-resistant Staphylococcus aureus (MRSA). One mesh type was implanted per animal. Animals were euthanized after 7 days, and implants were assessed for abscess formation, bacterial colonization, and mechanical strength. RESULTS: In the rat study, Phasix™ and Bio-A® exhibited similar biocompatibility, although Bio-A® demonstrated a significantly greater inflammatory response at 4 weeks compared to Phasix™ (p < 0.01). Morphometric analysis demonstrated rapid resorption of Bio-A® implants with initially thicker repair sites at 2, 4, 8, and 12 weeks (p < 0.0001), which transitioned to significantly thinner sites compared to Phasix™ at 16 and 24 weeks (p < 0.0001). In the rabbit bacterial inoculation study, Phasix™ exhibited significantly lower abscess score (p < 0.001) and bacterial colonization (p < 0.01), with significantly greater mechanical strength than Bio-A® (p < 0.001). CONCLUSIONS: Host response, resorption, repair thickness, strength, and bacterial colonization suggest a more stable and favorable outcome for monofilament, macroporous devices such as Phasix™ relative to multifilament, microporous devices such as Bio-A® over time.