Three-dimensional personalized porous polyethylen cranioplasty in patients at increased risk of surgical site infection.

BACKGROUND: Surgical site infection (SSI) is the most consistently reported complication of cranioplasty. No material showed a categorical superiority in the incidence of infection. Porous polyethylene (PE) is considered a low risk material regarding SSI. However, the literature data are very limited. Thus, our objective was to verify the assumed low incidence of SSI after PE cranioplasty in patients at high risk of SSI. The primary objective was the infection rate, while secondary objectives were implant exposure, revision and cosmetic results. METHOD: Patients who underwent three-dimensional (3D) personalized PE cranioplasty in the period 2014-2023 were evaluated prospectively. Only patients with an increased risk of SSI, and a satisfactory clinical conditions were included in the study. RESULTS: Thirty procedures were performed in 30 patients. Cranioplasty was performed 23 times after hemispheric decompressive craniectomy, five times after limited size craniotomy and two times after bifrontal decompressive craniectomy. Risk factors for the development of infection were 18 previous SSIs, 16 previous repeated revision surgeries, four intraoperatively opened frontal sinuses and two times radiotherapy. Neither infection nor implant exposure was detected in any patient. All patients were satisfied with the aesthetic result. In two cases, a revision was performed due to postoperative epidural hematoma. CONCLUSIONS: Three-dimensional personalized PE cranioplasty is associated with an extremely low incidence of SSI even in high-risk patients. However, our conclusions can only be confirmed in larger studies.

Porous Polyethylene Terephthalate Nanotemplate Electrodes for Sensitive Intracellular Recording of Action Potentials.

New strategies for intracellular electrophysiology break the spatiotemporal limitation of the action potential and lead a notable advance in the investigation of electrically excitable cells and their network. Although successful applications of intracellular recording have been achieved by 3D micro/nanodevices, complex micro/nanofabrication processes preclude the progress of extensive applications. We address this challenge by introducing porous polyethylene terephthalate (PET) membrane to develop a new type of nanotemplate electrode. This nanotemplate electrode is manufactured following a fabrication process on a porous PET membrane by atomic layer deposition. The 3D nanotemplate electrodes afford intracellular access to cardiomyocytes to report intracellular-like action potentials. These controllable nanotemplate electrodes exhibit sensitive and prolonged intracellular recordings of action potentials compared with free-growing 3D nanoelectrodes. This study indicates that the optimized structure of the nanoelectrode significantly promotes the performance of intracellular recording to assess electrophysiology in the fields of cardiology and neuroscience at an action potential level.

Vertically Oriented Porous PET as Template to Integrated Metal Halide for High-Performance Large-Area and Ultra-Flexible X-Ray Detector.

High-performance X-ray detectors have immense potential in medical and security inspections. However, the current X-ray detectors are limited in flexible, high-spatial-resolution large-scale detection, and integration for imaging. Here, nuclear track-etched porous polyethylene terephthalate (PET) is developed as the template for preparing uniform, large-area (≥105 cm2 ), and flexible metal halide (MH)-based X-ray detectors. Adjustable high-density vertically oriented porous PET with adjustable thickness can provide proper physical support for flexible thick absorption film, thus improving X-ray absorption ability with excellent bending stability. Moreover, vertical channels can block the ion migration, lateral charge diffusion, and water/oxygen attacks, increasing activation energy for ionic transport, charge collection rate of electrodes, and environmental stability. Hence, the related detectors eventually obtain large sensitivity (6722 µC Gyair -1 cm-2 ), low detection limit (1.87 nGyair s-1 ), and high spatial resolution (5.17 lp mm-1 ) compared to the detectors without porous PET template. Meanwhile, the device shows no degradation after storage or working under various thermal attacks. MH-filled-PET is also monolithically integrated on the bottom circuit with different MHs and it is applied to single-pixel mode and fast linear-array imaging in a broad range of X-rays photon energy (20 to 160 keV).

Single-incision endoscopic-assisted temporoparietal fascia harvest for single stage auricular reconstruction.

INTRODUCTION: The temporoparietal fascia flaps (TPFF) have been widely used to cover the framework in auricular reconstructions. However, flap harvesting is mostly done by open surgery which may be easier but often results in bad scarring and hair loss. We would like to present a series of cases using endoscopic-assisted flap harvesting techniques with only one single cosmetic auricular incision. PATIENTS AND METHODS: Prospective studies from June 2018 to September 2021 on patients who underwent single-stage total auricular reconstruction using autologous costal cartilage and porous polyethylene (PPE) framework. Variables include age, gender, flap survivability as well as visual results and complications. RESULTS: A total of 61 TPFFs were harvested to cover 15 autologous costal cartilages and 46 PPE frameworks in 60 patients (one patient had operation on both sides). TPFF harvests are performed by endoscopic techniques with one single auricular incision. There was no flap necrosis, no bleeding and no cases required framework removal. Only 7/61 (11.5%) ears had small framework exposure which resolved on their own or only required local skin flap coverage and 1 ear had frontal nerve injury. CONCLUSION: Single-stage auricular reconstruction is a difficult surgery, yet greatly beneficial to young children. Through a single-incision endoscopic technique, we can obtain sufficiently large high-survivability TPFFs ensuring full coverage of the autologous costal cartilage or PPE framework. This method is reliable, and reproducible with advanced training. After reviewing the literature, we can state that our report probably includes the largest endoscopic-assisted TPFF harvesting series and the first to implement single-incision endoscopic technique in auricular reconstructions.

Delayed onset porous polyethylene implant-related inflammation after orbital blowout fracture repair: four case reports.

BACKGROUND: Porous polyethylene implants are commonly used in orbital blowout fracture repair because of purported biocompatibility, durability, and low frequency of complications. Delayed inflammation related to porous polyethylene sheet implants is very rare and no case series of this condition have been reported. CASE PRESENTATION: This is a retrospective review of clinical presentations, radiographic findings, histopathological findings, treatments, and outcomes of patients who developed delayed complications in orbital blowout fracture repair using porous polyethylene sheets. Four male patients were included with a mean age of 49 years (range 35-69 years). Blowout fracture repair was complicated with implant-related inflammation 10 months, 2 years, 3 years, and 8 years after surgery. Chronic and subacute orbital inflammatory signs were noted in two patients and acute fulminant orbital inflammation was found in two patients. Three patients developed peri-implant abscesses and one patient had a soft tissue mass around the implant. All patients underwent implant removal and two of these patients with paranasal sinusitis had sinus surgery. Histopathological findings revealed chronic inflammatory changes with fibrosis, and one patient had foreign body granuloma with culture positive Staphylococcus aureus. CONCLUSIONS: Delayed complications with porous polyethylene sheets used in orbital blowout fracture repair may occur many years following the initial surgery in immunocompetent patients. Low-grade or fulminant inflammation could complicate blowout fracture repair related with the implant.

Ovine model for auricular reconstruction: porous polyethylene implants.

OBJECTIVES: We developed a large animal model for auricular reconstruction with engineered cartilage frameworks and evaluated the performance of porous polyethylene auricular implants in this model. METHODS: Eighteen high-density porous polyethylene auricular frameworks were implanted subcutaneously in the infra-auricular areas of 9 sheep. The implants were harvested 17 weeks later for gross and histologic examination. The perioperative and postoperative courses were carefully documented. RESULTS: Five implants became exposed, and 2 implants needed to be removed at 7 weeks. Additionally, 1 infected implant was removed at 2 weeks. Seromas developed in 2 implants because of drain failures and were drained successfully during the first postoperative week. There were no other surgical site complications. The remaining 10 implants had an acceptable cosmetic appearance at 17 weeks. CONCLUSIONS: The perioperative complication rate in the ovine porous polyethylene auricular implant model was higher than that reported for auricular reconstructions in humans. The implant exposures were likely caused by ischemia and excessive stress on the thin overlying skin, because vascularized flap coverage was not used. The histologic findings were comparable to the results reported for other animal models. This large animal model is appropriate for auricular reconstruction experiments, including engineered constructs.

Salvage of Infected Alloplastic Ear Reconstructions via Negative Pressure Wound Therapy.

This is the first description of Negative Pressure Wound Therapy (NPWT) use in rescuing alloplastic ear reconstructions. Previously considered a sign of certain impending failure, severe infections with frank purulence can be salvaged. As a more recently developed technique, porous polyethylene (PPE) ear reconstruction provides benefits when compared to rib techniques. Increasing surgeon awareness of complication management may lead to further adoption of the technique and improve reconstructive results. Described herein are two cases of draining infections following PPE ear reconstruction that were salvaged with satisfactory results. Laryngoscope, 134:4122-4125, 2024.

Hemifacial Microsomia Surgical Approach and Anotia Reconstruction: A Case Report.

BACKGROUND/AIM: Hemifacial microsomia (HFM) is the second most common congenital anomaly of the craniomaxillofacial region after the cleft lip and palate. This malformation is characterized by unilateral mandible and ear hypoplasia. Treatment varies and depends on different phenotypes. Severe deficiencies require multiple reconstructive surgeries to address facial asymmetries. This study aimed to review the surgical approach and evaluate the postoperative results of a case with right hemifacial microsomia and anotia. CASE REPORT: This is the case of a 35-year-old female patient who, after multiple graft operations in the right mandible due to hemifacial microsomia, was operated for auricle reconstruction. Initially, a three-dimensional custom made Medpor (porex) was used, covered by the superficial temporal fascia. Subsequently, due to inflammation and partial exposure of this porous polyethylene implant (PPI), a temporalis muscular flap along with the deep temporal fascia were used as a salvage operation. Ten months later, the patient underwent deep plane face lift combined with open rhinoplasty. Lefort I osteotomies and transoral lip lengthening through a transection of the levator nasi septi muscle were also performed. Ear helix reconstruction was completed with a rotation scalp flap after tissue expansion. The patient had an uncomplicated postoperative course with an aesthetically acceptable result. CONCLUSION: As a congenital disorder, hemifacial microsomia is present at birth and successful reconstruction is of fundamental importance for the smooth integration of these individuals into society. The multiple asymmetries, the affected topographic area of the face, as well as the onset in neonatal age constitute a challenge for reconstructive surgery.

Appropriate Use of Implants in the Nose.

Alloplastic materials are well suited for use in rhinoplasty in the right clinical scenarios, specifically in patients with platyrrhine noses and in challenging revision cases. The most commonly used materials today are silicone and high-density porous polyethylene. Both implant materials carry a unique set of properties and offer various advantages and disadvantages for use. Complications can be minimized with appropriate utilization of implants and using proper technique.

Implants and spacers for paralytic ectropion: Literature review and assessment of a thin-profile porous polyethylene implant.

Purpose: There is no ideal treatment paradigm for paralytic ectropion. This study evaluated lower eyelid spacers and the efficacy of a novel lower eyelid thin profile, bio-integratable, porous polyethylene. Methods: A retrospective review of 15 consecutive patients who underwent thin-profile porous polyethylene implantation and canthoplasty for paralytic ectropion was carried out. A comprehensive literature review of spacers for paralytic ectropion and retraction using the Pubmed database with search terms "[implant or graft or spacer] and [paralytic ectropion or paralytic retraction]," "graft and paralysis and ectropion," "implant and paralysis and ectropion," "graft and paralysis and retraction," and "implant and paralysis and retraction" was carried out. Results: The mean patient age was 69 years (range: 50-88). Lagophthalmos improved from a mean of 5.7 mm (SD = 3.3, range 3-14 mm) to 1.4 mm (SD = 1.1, range 0-3.5 mm), P < 0.0001. MRD 2 improved from a mean of 6.7 mm (SD = 2.3, range 2-12 mm) to 4.2 mm (SD = 0.9, range 3-6 mm), P = 0.0005. No patients needed additional lower eyelid surgery. There were no implant exposures at a mean follow-up of 7.6 months (SD = 7.9, range 0.7-21.6 months). Detailed literature review revealed that hard palate and ear cartilage are the most reported spacers, each with unique disadvantages. Conclusion: The thin-profile porous polyethylene implant is a useful addition to the management of symptomatic paralytic ectropion. Meaningful comparison of lower eyelid spacers is difficult because of variations in surgical technique, spacer size, and poorly reported outcome data. No spacer proves superior.

Novel method for high-density porous polyethylene ear reconstruction stent remodeling to achieve high satisfactory outcomes.

OBJECTIVE: We aimed to explore a novel method for ear reconstruction stent remodeling to achieve high patient satisfactory outcomes. METHODS: This study is a retrospective review of patients with congenital or acquired ear defects who were prepared for one-stage ear reconstruction with high-density porous polyethylene stent between May 2020 and May 2021. A standardized data collection template was used to collect related variables. In this study, the detailed reconstruction surgery process is carefully described, and the postoperative healing process of the ear reconstruction was closely observed. RESULTS: A total of 26 patients for one-stage ear reconstruction with high-density porous polyethylene stent or autogenous costal cartilage scaffolds were admitted to the department of plastic surgery in our hospital between May 2020 and May 2021. All patients were followed until their ear flaps were alive and details of the ear shape were revealed. The patients with new remolding method were no severe complications and only a patient had stent exposure, and were highly satisfied with both appearance and function. CONCLUSIONS: The application of novel remodeling method is a promising way for ear reconstruction stent shaping with little postoperative complication and excellent postoperative patient satisfaction.

TNF-α-Inhibition Improves the Biocompatibility of Porous Polyethylene Implants In Vivo.

BACKGROUND: To improve the biocompatibility of porous polyethylene (PPE) implants and expand their application range for reconstructive surgery in poorly vascularized environments, implants were coated with tumor necrosis factor α (TNFα) inhibitor Etanercept. While approved for systemic application, local application of the drug is a novel experimental approach. Microvascular and mechanical integration as well as parameters of inflammation were analyzed in vivo. METHODS: PPE implants were coated with Etanercept and extracellular matrix (ECM) components prior to implantation into dorsal skinfold chambers of C57BL/6 mice. Fluorescence microscopy analyses of angiogenesis and local inflammatory response were thrice performed in vivo over a period of 14 days to assess tissue integration and biocompatibility. Uncoated implants and ECM-coated implants served as controls. RESULTS: TNFα inhibition with Etanercept led to a reduced local inflammatory response: leukocyte-endothelial cell adherence was significantly lowered compared to both control groups (n = 6/group) on days 3 and 14, where the lowest values were reached: 3573.88 leukocytes/mm-2 ± 880.16 (uncoated implants) vs. 3939.09 mm-2 ± 623.34 (Matrigel only) vs. 637.98 mm-2 + 176.85 (Matrigel and Etanercept). Implant-coating with Matrigel alone and Matrigel and Etanercept led to significantly higher vessel densities 7 and 14 days vs. 3 days after implantation and compared to uncoated implants. Mechanical implant integration as measured by dynamic breaking strength did not differ after 14 days. CONCLUSION: Our data show a reduced local inflammatory response to PPE implants after immunomodulatory coating with Etanercept in vivo, suggesting improved biocompatibility. Application of this tissue engineering approach is therefore warranted in models of a compromised host environment.

Effectiveness of bilayer porous polyethylene membrane for alveolar ridge preservation: A randomized controlled trial.

BACKGROUND: Porous polyethylene has been successfully used in several medical applications with good outcomes. Based on this, a new bilayer porous polyethylene membrane (B-PPM) was developed for possibly being used as a membrane in alveolar ridge preservation. PURPOSE: To evaluate the clinical efficacy of a new B-PPM in comparison to high-density polytetrafluoroethylene membrane (d-PTFE) in alveolar ridge preservation. MATERIALS AND METHODS: Thirty patients were randomized into two groups according to the membranes used to cover the socket (B-PPM or d-PTFE). Wound healing was monitored at day 1, 3, 7, 14, 28, and 4 months postoperatively. Dimensional changes of alveolar ridge were measured immediately after tooth extraction and at 4 months later using intraoral scanner and cone beam computed tomography. Bone cores were harvested before implant placement. Implant stability at insertion and prior to prosthesis delivery were also measured. RESULTS: No significant difference in socket wound closure between groups was observed excepting at day 14 that B-PPM showed a faster wound closure than d-PTFE (P = .03). Greater bone resorptions were seen on buccal than lingual side and on coronal than apical part of the alveolar ridge. No significant difference in dimensional changes of alveolar ridge, new bone formation, connective tissue content, residual bone grafts, and implant stability between two groups. CONCLUSION: B-PPPM was safe and effective for alveolar ridge preservation.

Vascularization Strategies for Porous Polyethylene Implants.

Porous polyethylene (pPE) is a frequently implanted biomaterial in craniofacial reconstructive surgery. Its rapid vascularization and tissue incorporation are major prerequisites to prevent complications, such as material infection, migration, and extrusion. To achieve this, several sophisticated strategies have been introduced and evaluated during the last 20 years. These include (i) the angiogenic stimulation of the host tissue with epidermal growth factor, basic fibroblast growth factor or macrophage-activating lipopeptide-2, (ii) material modifications, such as increase of surface roughness and incorporation of bioactive glass particles, (iii) surface coatings with growth factors, glycoproteins, acrylic acid, arginine/glycine/aspartic acid peptide as well as components of the plasminogen activation system and autologous clotted blood or serum, and (iv) the seeding with fibroblasts, chondrocytes, stem cells, or adipose-tissue-derived microvascular fragments. The majority of these approaches showed promising results in experimental studies and, thus, may be capable of improving the success rates after pPE implantation in future clinical practice.

Biological coating with platelet-rich plasma and adipose tissue-derived microvascular fragments improves the vascularization, biocompatibility and tissue incorporation of porous polyethylene.

Porous polyethylene (pPE) is a commonly used biomaterial in craniofacial reconstructive surgery. However, implant failure due to insufficient vascularization represents a major issue. To overcome this problem, we herein introduce an effective strategy to improve the vascularization and incorporation of pPE. Adipose tissue-derived microvascular fragments (MVF) from transgenic green fluorescent protein (GFP)+ mice were suspended in platelet-rich plasma (PRP) for the coating of pPE. PRP/MVF-coated pPE as well as PRP-coated and uncoated controls were subsequently implanted into the dorsal skinfold chamber and the flanks of GFP- wild-type mice to analyze their in vivo performance throughout 2, 4 and 8 weeks by means of intravital fluorescence microscopy, histology and immunohistochemistry. The GFP+/GFP- cross-over design allowed the identification of GFP+ MVF within the implants. Shortly after implantation, they rapidly reassembled into new blood-perfused microvascular networks, resulting in a significantly accelerated vascularization of PRP/MVF-coated pPE when compared to both controls. The overall numbers of rolling and adherent leukocytes within the microcirculation as well as macrophages, multi-nucleated giant cells and mast cells around the implants did not differ between the three groups. However, in contrast to uncoated controls, PRP/MVF-coated and PRP-coated pPE promoted pro-angiogenic M2 macrophage polarization at the implantation site. These findings demonstrate that PRP/MVF-coating represents a highly effective strategy to enhance the vascularization, biocompatibility and tissue incorporation of pPE. STATEMENT OF SIGNIFICANCE: The clinical in vivo performance of implanted biomaterials is crucially dependent on their adequate incorporation into the body. To achieve this, we herein introduce an effective biological coating strategy. Our results demonstrate that coating with PRP and MVF accelerates and enhances the vascularization, biocompatibility and tissue incorporation of porous polyethylene. Because this type of biological coating is easily applicable on any type of biomaterial, our approach may rapidly be translated into clinical practice to improve the outcome of various regenerative approaches.

Clinical and histological evaluations of alveolar ridge augmentation using a novel bi-layered porous polyethylene barrier membrane.

Guided bone regeneration (GBR) is an effective alveolar ridge reconstruction technique used before or at implant placement. The combination of various barrier membranes and bone substitutes has been employed. This study aimed to perform a preliminarily evaluation of the safety and performance of a new nonabsorbable bi-layered porous polyethylene (PPE) membrane, in combination with a freeze-dried cortical bone allograft in posterior mandibular ridge augmentation. Fifteen adults who had combined posterior mandibular defects were included for ridge augmentation via GBR using PPE membrane and allograft before implant placement. The keratinized mucosa width (KW), ridge width (RW), ridge height (RH), distance from measurement matrix to bone (DMB), and horizontal alveolar width at 14.0 mm apical to the occlusal plane (HAW) were clinically measured at 15 intended implant sites before and after the augmentation. Fifteen biopsy specimens were harvested at the implant sites for histological analysis. All the subjects completed the whole study. The KW and RH showed minor gains by 0.2 ± 1.4 mm and 0.9 ± 2.3 mm respectively; however, no statistically significant differences were found between, before, and after the augmentation (P > 0.05). In contrast, the RW and HAW significantly increased by 4.8 ± 1.6 mm and 2.3 ± 1.7 mm, respectively, (P ≤ 0.001), while DMB significantly decreased by 1.0 ± 0.8 mm after treatment (P < 0.001). Histological analysis revealed that allograft underwent active bone remodeling. The PPE membrane was adequately safe and efficient to use with allograft in GBR for the reconstruction of combined ridge defects. Although some complications were observed, these were manageable and subsequently lead to successful implant placement for all the subjects. However, further randomized controlled trials are still needed to confirm these findings.

Porous Polyethylene Ear Reconstruction.

The use of a porous polyethylene implant covered with a well-vascularized fascial flap allows ear reconstruction at an early age (before school) with minimal morbidity and psychological trauma. Excellent outcomes with minimal morbidity can be obtained using this technique. This type of microtia reconstruction provides a more holistic approach because it is done at a younger age, in a single stage, as an outpatient and could address the functional hearing issues earlier.

Development of Chronic Sphenoid Sinusitis After Sellar Reconstruction with Medpor Porous Polyethylene Implant.

OBJECTIVE: The Medpor porous polyethylene implant is reported to be safe and effective for sellar reconstruction after transsphenoidal surgery (TSS). However, we have observed several cases of delayed chronic sphenoid sinusitis related to the implant. The purpose of this study is to describe the presentation and management of implant-related sphenoid sinusitis after sellar reconstruction. METHODS: This is a retrospective study of patients who underwent endonasal TSS with Medpor sellar reconstruction between December 2008 and January 2013 at a tertiary care institution. Patient demographics, initial surgical management, sinonasal symptoms, postoperative imaging, sinusitis management, and resulting outcomes were analyzed. RESULTS: From 2008-2013, 139 patients underwent sellar reconstruction using Medpor. Five patients (3.6%) presented between 8 and 60 months after surgery with chronic sphenoid sinusitis that required surgical management. All 5 patients presented as outpatients for management of headaches and nasal drainage, 4 patients experienced chronic nasal congestion, and 3 patients noted recurrent sinusitis. At the time of revision surgery, all 5 patients were found to have mucosal inflammation and edema surrounding the implant, and 4 of the 5 had an exposed or partially extruded implant that was removed. CONCLUSIONS: Reconstruction of the sellar floor may be performed after TSS to prevent postoperative complications. Although porous polyethylene implants have previously been described as safe and effective for this purpose, surgeons should be aware of the risk of subsequent implant extrusion and chronic sphenoid sinusitis that can occur in a delayed manner.

Auricular Reconstruction Using Porous Polyethylene Implant Technique.

Alloplast-based ear reconstruction has become more popular over the years because it offers many advantages compared with the traditional staged autologous costal cartilage approach. Advantages include earlier reconstruction in the setting of microtia, fewer procedures, less donor site morbidity, shorter surgeon learning curve, and improved consistency in the final aesthetic result. Although other implantable materials have been used in auricular reconstruction with variable success, porous high-density polyethylene frameworks combined with recent advances in the creation of the soft tissue coverage have significantly improved outcomes with minimal complications and long-term viability. This article describes the authors' technique.

Auricular reconstruction with polyethylene implants or silicone prosthesis: A single institution experience.

Auricular reconstruction is usually necessary in patients with congenital malformations, after traumatic ear amputations or in cases of neoplastic ear disease. Thirty-nine patients who underwent an auricular reconstruction with either silicon prosthesis (21 patients) or porous polyethylene (18 patients) between 2002 and 2013 were retrospectively analyzed at a tertiary academic institution. A total of 25 male und 14 female patients were included in the study. In all, 43 implants were installed in 39 patients. An implant failure was not observed in any of the examined groups. An operative revision was necessary in 5 patients in the silicon prosthesis group (N = 21) and in 4 patients in the porous polyethylene group (N = 18). The most common side effect in the porous polyethylene group was the formation of retroauricular adhesions in 11.1 % by postoperative scaring, while in the silicone prosthesis group 71.4 % of the patients presented with skin reactions around the titanium implants. Our study shows that both techniques are valuable and should be offered to patients in cases of auricular reconstruction due to the low rate of severe complications and the good functional results of both techniques.