Porous High-density Polyethylene Research Articles

Application for MEDPOR Surgical Implant in Modified Penile Elongation: Review of 19 Cases.

To investigate the application of MEDPOR surgical implant in modified penile elongation. The suspensory ligaments were divided, and cavernous bodies of crus were partially mobilized, so as to release part of the cavernous bodies from inferior ramus of pubis. Then, the penis was elongated sufficiently. MEDPOR surgical implants (MEDPOR; high-density porous polyethylene, Howmedica Osteonics Corp. Newnan, Ga) were inserted between the cavernous bodies and pubic symphysis. Local fat flap was transposed to fill the front space of pubis to make sure of the effective elongation of penis and improve the appearance of mons pubis. Nineteen cases of micropenis were treated. The average length of the penis was 5.23 cm in the static state and 7.83 cm in erectile state before operation. After the operation, it increased to 8.63 cm in the static state and 11.36 cm in erectile state. Application for MEDPOR surgical implant in modified penile elongation can make sure of the effective elongation of penis and improve the appearance of mons pubis.

Solid Implants in Facial Plastic Surgery: Potential Complications and How to Prevent Them.

Allogenic implants are an effective alternative to autologous grafts in the reconstruction of facial defects. These implants are used to reconstruct a variety of bony and soft-tissue defects, including the frontal and temporal regions; internal orbit; infraorbital rim; malar, paranasal, and nasal regions; mandible; and chin. In comparison to their autologous counterparts, alloplastic materials are more readily available, lack donor-site morbidity, decrease surgical time and cost, and still have relatively good postoperative tissue tolerance. However, these implants are not without their own spectrum of complications. Common solid implant materials include silicone, GoreTex (expanded polytetrafluorethylene; W. L. Gore & Associates Inc., Flagstaff, AZ), MedPor (high-density porous polyethylene; Porex Industries, Fairburn, GA), and Mersilene mesh (nonresorbable polyester fiber; Ethicon, Somerville, NJ). Each of these materials poses certain complication risks based on their surface contour (smooth vs. porous), pliability, and reactivity with surrounding tissue. In addition, certain implant locations within the head and neck are at risk for different postoperative complications. Although there are no evidence-based guidelines for implant reconstruction to help avoid common complications, there are several principles and techniques that are commonly employed by surgeons to help reduce complication rates. These include careful patient selection, proper choice of operative procedure, infection control practices (including pre/intraoperative systemic antibiotics, meticulous aseptic technique, impregnation/soaking of implant in antibiotic, irrigation of implant pocket with antibiotic, careful closure of tissue layers, and postoperative oral antibiotics), preoperative implant shaping, choice of surgical approach, and intraoperative surgical techniques. Larger, controlled trials are needed to confirm the efficacy of the aforementioned techniques in the reduction of postoperative complications.

Comparative study of the safety and efficacy of the Ahmed glaucoma valve model M4 (high density porous polyethylene) and the model S2 (polypropylene) in patients with neovascular glaucoma

Abstract Objective To prospectively evaluate the safety and efficacy of the Ahmed glaucoma valve model M4 (high density porous polyethylene plate; Medpor) compared with the model S2 (polypropylene plate). Method Mexican patients with neovascular glaucoma were randomly included for each group (M4 and S2). They were operated on using conventional techniques and creating a sub-episcleral tunnel to place the valve tube in the anterior chamber. After one year of follow-up, the results were evaluated with respect to a post-operative reduction in pressure, changes in visual acuity, the need for drugs, and complications, as well as the demographic characteristics of each group. Each operation using the M4 valve was performed by a single surgeon (FGC). Those operated on using the S2 model had their surgery performed by the staff surgeons at the Glaucoma Department of the Mexican Association to Prevent Blindness (APEC). Results Each group (M4 and S2) contained 21 eyes of 21 Mexican patients with a diagnosis of neovascular glaucoma, leading to a total of 42 patients undergoing surgery. The mean preoperative intraocular pressure (IOP) was 43.5 (±11.8), and 42.24 (±12.84) mmHg for the M4 and S2 groups, respectively. After one year of follow-up, the IOP reported was 18.9 (±9.7) mmHg for the final 18 patients in the M4 group, and 16.38 (±9.76) mmHg for the 21 patients in the S2 group. Discussion The design of a drainage valve device such as that of Ahmed has characteristics such as moderate control of IOP, thanks to the valve component in the immediate post-operative period, which makes them safer than other non-valve devices. This avoids an excess of flat chambers and the presence of low IOPs, which can lead to bleeding in the early post-operative period due to the weak desmosomal junctions of the newly formed vessels, with the advantage of maintaining suitable control of IOP from the first day after surgery. Conclusion Further studies with longer follow-up with a larger number of patients are needed to evaluate the effectiveness of this porous coating in the control of neovascular glaucoma.

Application of implantation of high-density porous polyethylene artificial nasolacrimal canal for complex orbital fracture combined with lacrimal duct obstruction

Objective To evaluate the curative effect of high-density porous polyethylene artificial nasolacrimal canal (medpor) implantation for complex orbital fracture combined with lacrimal duct obstruction. Methods Seventeen eyes of 17 patients with traumatic lacrimal duct obstruction were treated with artificial nasolacrimal canal implantation. The patients were followed up for 6-36 months after the surgery. Results The epiphora disappeared or improved in all the patients. Postoperative complications including granulation hyperplasia and polyps growing in conjunctival side of the artificial nasolacrimal canal happened in 2 cases(11.8%) and scar covering around the nasolacrimal canal happened in 2 cases (11.8%). Conclusion Artificial nasolacrimal canal (medpor) implantation can obviously improve epiphora in patients with traumatic lacrimal duct obstruction. The method is safe and effective. Key words: Lacrimal duct obstruction, traumatic; Orbital fracture, complex; Artificial nasolacrimal canal(medpor)

Estudio comparativo de la seguridad y eficacia entre el dispositivo valvular de Ahmed modelo M4 (polietileno poroso de alta densidad) y el modelo S2 (polipropileno) en pacientes con diagnóstico de glaucoma neovascular

ObjectiveTo prospectively evaluate the safety and efficacy of the Ahmed glaucoma valve model M4 (High density porous polyethylene plate; Medpor) compared with the model S2 (polypropylene plate). MethodMexican patients with neovascular glaucoma were randomly included for each group (M4 and S2). They were operated on using conventional techniques and creating a sub-episcleral tunnel to place the valve tube in the anterior chamber.After one year of follow-up, the results were evaluated with respect to a post-operative reduction in pressure, changes in visual acuity, the need for drugs, and complications, as well as the demographic characteristics of each group.Each operation using the M4 valve was performed by a single surgeon (FGC). Those operated on using the S2 model had their surgery performed by the staff surgeons at the Glaucoma Department of the Mexican Association to Prevent Blindness (APEC). ResultsEach group (M4 and S2) contained 21 eyes of 21 Mexican patients with a diagnosis of neovascular glaucoma, leading to a total of 42 patients undergoing surgery. The mean preoperative intraocular pressure (IOP) was 43.5 (±11.8), and 42.24 (±12.84) mmHg for the M4 and S2 groups, respectively. After one year of follow-up, the IOP reported was 18.9 (±9.7) mmHg for the final 18 patients in the M4 group, and 16.38 (±9.76) mmHg for the 21 patients in the S2 group. DiscussionThe design of a drainage valve device such as that of Ahmed has characteristics such as moderate control of IOP, thanks to the valve component in the immediate post-operative period, which makes them safer than other non-valve devices. This avoids an excess of flat chambers and the presence of low IOPs, which can lead to bleeding in the early post-operative period due to the weak desmosomal junctions of the newly formed vessels, with the advantage of maintaining suitable control of IOP from the first day after surgery. ConclusionFurther studies with longer follow-up with a larger number of patients are needed to evaluate the effectiveness of this porous coating in the control of neovascular glaucoma.

Postoperative Complications in Craniomaxillofacial Reconstruction With Medpor.

Bone reconstruction in craniofacial surgery is a challenge for surgeons, who most commonly adopt the autogenous bone grafting and alloplastic implants in such procedures. Among the alloplastic materials, the high-density porous polyethylene is highlighted-Medpor (Medpor, Porex Surgical Inc, Newman, GA), considered to be pure polyethylene, with only 1 manufacturing process and standard pore size. The purpose of the current study has been to present through a review of literature and the types of complications derived from the use of Medpor in craniomaxillofacial bone surgery. A specific and sensitive database was initially created via PubMed, focusing on studies published in English peer-reviewed journals between 2004 and 2014, including case reports, experimental studies in humans, and prospective and retrospective studies. Forty articles were found at PubMed database. After analyzing their abstracts, 19 were selected, totaling 1453 patients and 121 complications, being the most commonly reported diplopia with 56 patients and infection with 6 patients. Most of the complications reported in the articles used for the development of the current review are not directly related to the use of the Medpor implant. The only complications directly related to the use of this biomaterial were cases of infection.

Analysis of complications after orbital reconstruction with Medpor implantation for the orbital blowout fracture

Objective To analyze the causes of complications after orbital reconstruction with high density porous polyethylene (Medpor) for the repair of orbital blowout fracture. Methods A retrospective analysis of patients with orbital blowout fracture treated with Medpor in our department was carried out. Results In 232 cases after postoperative follow up of 3 months, the visual function decreased significantly in 2 cases, endophthalmos was undercorrection in 7 cases, residual diplopia was observed in 2 cases and implant displacement was detected in 1 case. Conclusion There are many kinds of complications after orbital reconstruction with Medpor implantation for blow-out fracture of orbital floor wall, such as vision loss, enophthalmos, diplopia exacerbation, infection, and so on. The causes are related to the degrees of fracture, location, doctor's skill and experience, and postoperative functional training. The key points for successful repair of orbital fracture include effective prevention, correct analysis of causes and timely treatment. Key words: Blowout fracture, orbital; Medpor; Surgery, reconstrution; Effect, undesirable

Effect of wall suction on rotating disk absolute instability

This research investigates the effect of uniform suction on the absolute instability of Type I cross-flow modes in the boundary layer on a rotating disk. Specifically, it is designed to investigate whether wall suction would transform the absolute instability into a global mode, as first postulated in the numerical simulations of Davies & Carpenter (J. Fluid Mech., vol. 486, 2003, pp. 287–329). The disk is designed so that with a suction parameter of $0.2$, the radial location of the absolute instability critical Reynolds number, $Re_{c_{A}}=650$, occurs on the disk. Wall suction is applied from $Re=317$ to 696.5. The design for wall suction follows that of Gregory & Walker (J. Fluid Mech., 1960, pp. 225–234) where an array of holes through the disk communicate between the measurement side of the disk and the underside of the disk which is inside of an enclosure that is maintained at a slight vacuum. The enclosure pressure is adjustable so that a range of suction or blowing parameters can be investigated. The holes in the measurement surface are covered by a compressed wire porous mesh to aid in uniformizing the suction on the measurement surface of the disk. The mesh is covered by a thin porous high-density polyethylene sheet featuring a $20~{\rm\mu}\text{m}$ pore size which provides a smooth finely porous surface. A companion numerical simulation is performed to investigate the effect that the size and vacuum pressure of the underside enclosure have on the uniformity of the measurement surface suction. Temporal disturbances are introduced using the method of Othman & Corke (J. Fluid Mech., 2006, pp. 63–94). The results document the evolution of disturbance wavepackets in space and time. These show a temporal growth of the wavepackets as the location of the absolute instability is approached which is in strong contrast to the temporal evolution without suction observed by Othman and Corke. The results appear to support the effect of wall suction on the absolute instability postulated by Thomas (PhD thesis, 2007, Cardiff University, UK) and Thomas & Davies (J. Fluid Mech., vol. 663, 2010, pp. 401–433).

Ear Reconstruction in Young Children.

The use of a porous high-density polyethylene ear implant, rather than a costal cartilage framework, allows ear reconstruction in young children before they enter school. The fact that the growth of the normal ear matures early allows for good symmetry. If the implant is covered completely with a large, well-vascularized superficial parietal fascia flap and appropriately color-matched skin, an ear with excellent projection and definition can be obtained with minimal complications and long-term viability. Ear reconstruction in young children is preferred by the author because the necessary fascial flap coverage is thinner, easier to harvest than in older patients, and can be done in a single outpatient procedure with minimal discomfort or psychological trauma.

Plasma polymerization and rhBMP-2 immobilization on porous high density polyethylene for osteoinduction

Plasma polymerization and rhBMP-2 immobilization on porous high density polyethylene for osteoinduction

Application of computer-aided designing and manufacturing technology in the reconstruction of orbital blow-out fracture

Background Orbital blow-out fracture often results in the abnormalities of appearance and function of eye. Because of the special and complex anatomical structure of orbital cavity, it is difficult to design and manufacture the corresponding orbital implants. The computer-aided designing and manufacturing (CADM) technology provides a new approach to orbital implants. However, the clinical value of this method is still under evaluation. Objective This study was to investigate the application and the therapeutic effect of CADM for orbital blow-out fracture. Methods The clinical data of 74 eyes of 74 patients who received surgery for orbital blow-out fracture from July 2006 to July 2012 in Henan Eye Institute, Henan Eye Hospital were retrospectively analyzed. Fifty-eight patients underwent CADM implanted surgery and 16 patients received non-CADM surgery in the same period with matched age, gender and lateral eyes in both groups. The individualized 3D orbital implants were designed and manufactured by the technology of CADM and then were implanted in the bone defects in the CADM group, while the traditional hydroxyapatite artificial bone or high density porous polyethylene material (Medpor) was utilized in the non-CADM group with a fellow-up duration for 22 to 69 months. The best corrected visual acuity (BCVA), eyeball exophthalmos, ocular position, eye movement, diplopia and postoperative complications were evaluated. Results The preoperative BCVA were 0. 71±0. 37 and 0. 69±0. 41, and the postoperative BCVA were 0. 74±0. 38 and 0. 72±0. 41 in the CADM group and the non-CADM group, respectively, showing an insignificant intergroup difference (Fgroup=0. 043, P=0. 837), but a significant variation was found over time (Ftime =13. 576, P<0. 01). The BCVA was significantly improved after surgery compared with before surgery in both groups (both at P<0. 05). No significant differences were found in the number of eyes with curative and improved diplopia and eye movement disorders between the two groups during the fellow-up duration (Z=-0. 298, P=0. 766; Z=-0. 548, P=0. 584). The preoperative eyeball exophthalmos values were (3. 93±0. 99)mm and (3. 88±0. 97)mm and the postoperative ones were (0. 91±0. 67)mm and (1. 84±0. 80) mm in the CADM group and the non-CADM group, respectively, without significant difference between the two groups (Fgroup=3. 558, P=0. 063). However, the eyeball exophthalmos values after operation were remarkably lower than those before operation in both groups (both at P<0. 05). CT imaging displayed implants fitting well with fracture defect and attached to bone tissue accurately in all of the eyes in the CADM group, but in the non-CADM group, the bulge of implants damaging extraocular muscles or optical nerve was found in 2 eyes. No postoperative complication was seen throughout the fellow-up duration in the CADM group. Conclusions CADM technology for orbital blow-out fracture can reconstruct a 3D bony orbit and effectively repair ocular position and appearance, and furthermore restore eye movement and visual functions. The therapeutic outcome of CADM technology for orbital blow-out fracture is superior to conventional implants. Key words: Orbital fractures/surgery; Surgery, computer-assisted/methods; Titanium meshes/therapeutic use; Tomography, X-ray computed; Treatment outcome; Human

Porous polyethylene implants in facial reconstruction: Outcome and complications

The aim of the present study was to assess the indications, results and complications of patients treated with porous polyethylene (Medpor(®)) implants in the Department of Oral and Maxillofacial Surgery of VU Medical Centre, Amsterdam over 17 years. A total of 69 high-density porous polyethylene implants (Medpor(®) Biomaterial; Porex Surgical, Newman, GA) were used in forty patients (22 males, 18 females). All patients were analysed for gender, age, diagnosis, indications for surgery, follow-up period and postoperative complications. A mean age of 34.1 years was observed. The main reason for implant surgery was post-traumatic functional impairment (27.5%). Most implants were placed at the mandibular angel and the orbital floor. Unsatisfactory appearance scored the highest in postoperative complications (10.1%) followed by infection rate (7.2%). Comparing the number of implants placed over the years and the incidence of complications, makes the overall complications rate of porous polyethylene very low. A consensus about antibiotic prophylaxis is needed. The objective measurements in patient satisfaction and proper implant design would be of great use.

Acceleration of Medpor implant fibrovascularization with local vascular endothelial growth-factor injections: An experimental study

Objective: Medpor is a biocompatible, high-density porous polyethylene implant that is used for multiple indications in plastic surgery. The most frequent complications associated with the Medpor implant are infection and implant exposure. The primary cause of these complications is poor fibrovascularization of the Medpor implant and poor nourishment of the overlying skin. The present experimental study aimed to determine whether vascular endothelial growth factor (VEGF) could accelerate and increase Medpor implant fibrovascularization in vivo, and thereby improve local nourishment and prevent complications. Materials and Methods: The Medpor implant was inserted under the dorsal skin area in 40 Sprague-Dawley rats. 20 rats receiving local VEGF injections comprised the study group. The control group received saline injections. Fibrovascularization of the Medpor implants was compared. Results: In the rats injected with VEGF, the Medpor implant fibrovascularized faster, and there were more newly formed blood vessels, as compared with those in the control group. Conclusion: These findings have led to our use of VEGF-like agents that the accelerate angiogenesis in the Medpor implant as a means to reduce the incidence of such complications as infection and implant exposure.

Use of porous high-density polyethylene grafts in open rhinoplasty: no infectious complication seen in spreader and dorsal grafts.

ObjectiveThe aim of this study is to use porous high-density polyethylene grafts (Medpor) in open rhinoplasty and then assess complication rate and aesthetic outcomes.MethodsIn a prospective cohort study, we performed open rhinoplasty and employed Medpor as rhinoplasty grafts. Then we compared their complication rate.ResultsIn a total of 64 patients, 84 Medpor grafts -38 dorsal grafts, 23 strut grafts, 8 rim grafts, 5 button grafts and 10 spreader grafts – were utilized. Moreover, 5septal perforation repairs with Medpor were performed. The complication rates were 5.3% in dorsal graft (complication in dorsal graft was only movement of implant), 21.7% in strut graft and 25.0% in rim graft. No complication was seen in spreader and button grafts. All 5septal perforation repairs were successfully performed with the same rhinoplasty approach.ConclusionMedpor can be used as dorsal and spreader graft in reconstruction of severe nose deformity with lowest complication rate and without infectious complication and extrusion.

The application and progress of high-density porous polyethylene in the repair of orbital wall defect.

High-density porous polyethylene is a type of polymeric biomaterial. When used to efficiently fill the extensive orbital volume and correct enophthalmos caused by orbital wall defect, it has a significant advantage of biocompatibility, which results in a low rate of postoperative exposure and infection. The major disadvantage of this material is its radiolucency. However, with the development of imaging techniques, it is now possible to use multidetector computed tomography to directly contour the implant and describe its position. The use of tissue engineering involving high-density porous polyethylene will further improve its biocompatibility. At the same time, composite materials will play an important role in the repair of orbital wall defect.

Porous high-density polyethylene in functional rhinoplasty: Excellent long-term aesthetic results and safety

Experience with the use of porous high-density polyethylene (PHDPE) for reconstruction of the nasal framework has been limited. To confirm the safety and utility of PHDPE by analyzing aesthetic outcomes and assessing the frequency of complication related to PHDPE in a large, population-based, long-term follow-up study. A total of 151 patients who had undergone septoplasty and/or functional rhinoplasty using PHDPE were enrolled. PHDPE sheets were used for diverse purposes such as septal extension graft, spreader graft, columellar strut or dorsal augmentation graft. After a long-term follow-up period (mean [± SD] 39.5±27.8 months; range six to 101 months), postoperative aesthetic outcome was evaluated objectively (by independent surgeons) and subjectively (patient self-report). Complications related to PHDPE were estimated through review of medical records. The most common use of the PHDPE graft was for septal extension (n=80 [42.6%]) and spreader graft (n=58 [30.9%]). Results of aesthetic evaluation by surgeons were excellent in 61 cases (40.4%), good in 54 (35.8%) and fair in 34 (22.5%). According to patient self-report, 100 were 'satisfied' (66.2%) and 36 rated their new profile as 'better than the preoperative profile' (23.8%). Complications were reported in six cases (4.0% [five cases of extrusion and one case of infection]). All complications were resolved after the surgical removal of PHDPE sheets under local anesthesia. The present study demonstrated that PHDPE could be used in functional primary rhinoplasty with excellent long-term aesthetic results and safety.

Treatment of Postsurgical Temporal Hollowing With High-Density Porous Polyethylene

Temporal hollowing is most frequently an acquired defect and can be caused by a volumetric deficiency of bone, soft tissue, or both. Given high-density porous polyethylene's ease of use, customizability, long-term strength and resiliency, and successful application in other areas of the craniofacial skeleton, the authors have used it as the first-line material for reconstruction of temporal hollowing. Herein, we present 4 illustrative cases demonstrating this technique and further describe subtypes of the temporal defect with appropriate means of reconstruction. The cases were reviewed for comorbidities, intraoperative details, and the postoperative course. There were no complications, and all patients were pleased with their final result. High-density porous polyethylene is a safe, well-studied, and easily handled biomaterial that is useful for the treatment of temporal hollowing.

Ovine Model for Auricular Reconstruction

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. 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. 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. 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.

Problems associated with alloplastic materials in rhinoplasty.

PurposeAugmentation rhinoplasty using alloplastic materials is a relatively common procedure among Asians. Silicon, expanded polytetrafluoroethylene (Gore-tex®), and porous high density polyethylene (Medpor®) are most frequently used materials. This study was conducted to analyze revisional rhinoplasty cases with alloplastic materials, and to investigate the usage of alloplastic materials and their complications. We also reviewed complications caused by various materials used in plastic surgery while operating rhinoplasty.Materials and MethodsWe report 581 cases of complications rhinoplasty with alloplastic implants and review of the literature available to offer plastic surgeons an overview on alloplastic implant-related complications.ResultsAmong a total 581 revisional rhinoplasty cases reviewed, the alloplastic materials used were silicone implants in 376, Gore-tex® in 183, and Medpor® in 22 cases. Revision cases and complications differed according to each alloplastic implant.ConclusionOptimal alloplastic implants should be used in nasal structure by taking into account the properties of the materials for the goal of minimizing their complications and revision rates. A thorough understanding of the mechanism involved in alloplastic material interaction and wound healing is the top priority in successfully overcoming alloplastic-related complications.

Porous high-density polyethylene in functional rhinoplasty: Excellent long-term aesthetic results and safety

Porous high-density polyethylene in functional rhinoplasty: Excellent long-term aesthetic results and safety