Composite Prosthesis Research Articles

Traitement laparoscopique des éventrations de la paroi abdominale

Current management of incisional hernias is based on the tension free parietoplasty with prosthesis. This option is considered as the gold standard leading to a recurrence rate lower than 10%. Laparoscopic approach involves the placement of a composite intraperitoneal prosthesis obstructing the wall defect without anatomic reconstruction or peritoneal excision. This article describes the standard technique of the laparoscopic insertion of a prosthesis.

Tumeurs malignes osseuses du fémur proximal : exérèses et reconstructions

The femur upper extremity is the second most frequent localisation of bone primitive tumours. In most cases, reconstruction must be performed by the implementation of a composite total hip prosthesis with combined allograft. Resection includes the upper extremity of the femur together with the surrounding muscles, and the gluteï tendons. An allograft composite prosthesis is used, with the suture of the patient’s gluteal tendons on the allograft gluteal tendons. The distal prosthetic stem is fixed in the recipient femur. The prosthesis stability is ensured by a capsuloplasty and the tendon suture allows restoring adequate abduction. Rarely, the tumour spreads to the joint; in such case a total resection of the upper femur, capsule and acetabulum must be performed, using the Ollier approach. Femoral reconstruction consists of a combined composite prosthesis, while the pelvis is reconstructed by acetabular allograft in which a cup is fixed. Alternative solutions exist, such as a saddle prosthesis. Upper extremity of the femur is the most frequent site of limb metastases. Palliative therapy is undergone for metastatic osteolysis, using a reconstruction prosthesis implanted in the healthy bone after resection of the osteolytic zone. The approach is a digastric trochanteric slide. A capsuloplasty stabilises the hip. This simple intervention allows rapid restoration of full weight bearing and early complementary radiotherapy.

Les reconstructions après résection tumorale de l’extrémité supérieure de l’humérus: À propos d’une série de 29 reconstructions avec un recul moyen de 7 ans

Purpose of the study Techniques available for shoulder reconstruction after resection of a tumor of the proximal humerus include scapulohumeral arthrodesis, humerus prosthesis with or without an allograft, inverted prostheses, and massive allografts. The purpose of this study was to review clinical and radiological outcomes in a series of 29 patients (20 men and 9 women) who underwent resection-reconstruction of the proximal humerus and to establish from these cases a decision making algorithm for therapeutic indications as a function of tumor invasion. Material and methods The tumors were 20 chondrosarcomas, five osteosarcomas, two Ewing sarcomas and one malignant hemangiopericytoma. In 17 patients epiphyso-metaphyseal or epiphyso-metaphyso-diaphyseal resection was performed with preservation of the abductor muscles (type S34A or S345A according to the Musculoskeletal Tumor Society classification). For 12 patients epiphyso-metaphyseal or epiphyso-metaphyso-diaphyseal resection was performed without preservation of the abductor muscles (type S34B or S345B). Reconstruction was achieved using a centromedullary cemented nail in one patient, scapulohumeral arthrodesis in three, a massive humerus prosthesis in 15, and composite humerus prosthesis in three and an inverted prosthesis in seven. The functional score of the Musculoskeletal Tumor Society (MSTS) and standard x-rays were used to assess outcome. Results Mean follow-up was 85 months (range 16-300). The mean MSTS score was 88% for inverted prostheses, 76% for composite prostheses, 72.6% for massive prostheses, 75% for scapulohumeral arthrodeses, 67% for massive prostheses, and 80% for cemented centromendullary nail. Five patients died from their malignant disease and one from another cause. Four patients are alive but with active disease after a mean follow-up of 108 months and 19 patients (65.5%) are alive and free of locoregional recurrence or metastasis after a mean 83.5 months. We had 28 complications. Glenohumeral instability was the most frequent (11 cases). Discussion Resection of the upper portion of the humerus should be performed to achieve cancerologically satisfactory tumor resection and enable shoulder resection, if possible, with preservation of a viable and functional abductor system. The functional outcome after such reconstruction depends on the type of bony resection, but also on the sacrifice of the rotator cuff and the deltoid muscle. In light of our experience and results in the literature, we advocate, despite the small number of cases for the different reconstructions, the following decision-making algorithm after resection of the proximal humerus without joint invasion: when the resection removes the rotator cuff and the deltoid (or the axillary nerve), there are two options: scapulohumeral arthrodesis or massive humerus prosthesis for patients who do not desire a complex therapy with a long postoperative period; when the resection preserves the rotator cuff and/or the deltoid muscle, reconstruction can be achieved with a composite (inverted or not) prosthesis with suture of the cuff tendons. We prefer the inverted composite prosthesis; if the deltoid muscle can be preserved but not the rotator cuff, the composite inverted prosthesis appears to be the most logical solution, but scapulohumeral arthrodesis can be proposed in selected cases.

Temporary closure of the abdomen using a new composite prosthesis (PL-PU99)

Background Temporary abdominal wound closure is sometimes desirable when tension-free approximation of the wound edges is impractical or when reexploration is planned. Methods The behavior of a composite prosthesis (PL-PU99) designed by our group was evaluated as a method of temporary abdominal closure in white New Zealand rabbits. After a 7 cm long midline laparotomy, a spindle-shaped 4 cm (maximum width) by 7 cm (length) fragment of PL-PU99 was sutured to the edges of the peritoneal, muscular, and fascial abdominal tissues, so that the biomaterial remained in contact with the exterior. The PL-PU99 composite is composed of a polypropylene mesh adhered to a sheet of polyurethane with an acrylic cement. At 7 and 14 days after implant, animals were sacrificed and specimens taken for morphological, ultrastructural, morphometry of the neoperitoneum, and immunohistochemical (macrophage reaction, RAM-11) analysis. Results No death or signs of infection or rejection of the prostheses were recorded. No adhesions could be macroscopically observed between the composite and the intestinal loops. The biomaterial achieved a good seal, no leakage of fluids being detected. Fourteen days after implant, the neoperitoneum formed on the prosthesis was of an even structure and was made up of organized, vascularized connective tissue covered by an uninterrupted mesothelium. Conclusions The PL-PU99 prosthesis shows optimal behavior at the prosthesis/visceral peritoneum interface, making it ideal for its use in the temporary closure of the abdomen. The implanted composite may also prove useful for the permanent repair of the abdominal wall.

Coculture of Mesenchymal Stem Cells and Respiratory Epithelial Cells to Engineer a Human Composite Respiratory Mucosa

In this study, we describe a novel in vitro reconstitution system for tracheal epithelium that could be useful for investigating the cellular and molecular interaction of epithelial and mesenchymal cells. In this system, a Transwell insert was used as a basement membrane on which adult bone marrow mesenchymal stem cells (MSCs) were cultured on the lower side whereas normal human bronchial epithelial (NHBE) cells were cultured on the opposite upper side. Under air-liquid interface conditions, the epithelial cells maintained their capacity to progressively differentiate and form a functional epithelium, leading to the differentiation of mucin-producing cells between days 14 and 21. Analysis of apical secretions showed that mucin production increased over time, with peak secretion on day 21 for NHBE cells alone, whereas mucin secretion by NHBE cells cocultured with MSCs remained constant between days 18 and day 25. This in vitro model of respiratory epithelium, which exhibited morphologic, histologic, and functional features of a tracheal mucosa, could help to understand interactions between mesenchymal and epithelial cells and mechanisms involved in mucus production, inflammation, and airway repair. It might also play an important role in the design of an composite prosthesis for tracheal replacement.

Sternal resection and reconstruction for primary malignant tumors

Background Primary malignant sternal tumors (PMST) are locally aggressive and their optimal surgical management still continues to evolve. Methods From 1986 to 2002, 38 patients (25 females/13 males) underwent radical resection of PMST. This series included 33 sarcomas, 17 of which had been radiation-induced, 3 hematologic tumors, and 2 carcinomas. Seventeen were high-grade tumors. Nine patients had received preoperative chemotherapy. Twelve patients required extensive skin excision. Eight total, seven subtotal, and 23 partial sternectomies were performed. Resection was extended to the anterior chest-wall in 4 patients, lung in 4, brachiocephalic vein in 3, superior vena cava in 2, and pericardium in 1. In 36 patients, chest wall stability was obtained by Marlex (n = 21) or Vicryl (n = 2) mesh and polytetrafluoroethylene patch (n = 13), with methylmethacrylate reinforcement in 12 patients. Soft tissue coverage was done by the pectoralis major muscles with skin advancement in 25 patients, a myocutaneous flap in 11, a breast transposition in 1, and a skin flap in 1. Omentoplasty was performed in 3 patients. Results One patient died from pneumonia. Two patients needed a tracheostomy after total sternectomy. No flap-related complication was observed. Four local septic complications required removal of the composite prosthesis with reoperations. Local recurrence occurred in 9 patients, 7 patients having a repeat resection. Metastases developed in eight. The 5-year overall and disease-free survival was 66% and 53%, respectively. The histologic grade of sarcomas was a survival predictor (high grade versus others p = 0.035). Conclusions Wide resection of PMST is necessary to minimize local recurrence. Large sternal defects are safely reconstructed with a musculocutaneous flap. We suggest that the use of methylmethacrylate should be limited to reconstruction after total sternectomy.

Tracheal Replacement in Rabbits with a New Composite Silicone-Metallic Prosthesis

A new composite silicone-metallic prosthesis was tested, studying the potential for respiratory epithelial covering over the biocompatible inner lining, in a rabbit survival model. Seven New Zealand White rabbits underwent near-total excision of their trachea and implantation of a sterile prosthesis. After 2 months, they were sacrificed and the prostheses were retrieved. Specimens were fixed and histologically examined for tissue reaction around the prosthesis, at the anastomotic lines, and particularly for the presence or absence of epithelialization of the inner lumen over the biocompatible surface. All rabbits survived the operation. At 2 months, the outer layer of the prosthesis was consistently covered with fibrosis and neutrophils. The inner layer showed necrotic cells and scant re-epithelialization over the biocompatible lining, up to 5 mm beyond the anastomosis, with no evidence of organized respiratory epithelium in the middle sections. The new prosthesis is a viable temporary solution for airway replacement in rabbits. Granulation tissue was not observed at the anastomosis, and re-epithelialization did occur, but failed to achieve full-length luminal covering. The potential for granulation tissue does not yet make this an ideal long-term solution. Improvements in prosthesis design or biocompatibility are required, and need to be re-evaluated before applicability for chronic use.

Shear in Flexure of Fiber Composites with Different End Supports

The integrity of fiber-reinforced composite (FRC) prostheses is dependent, in part, on flexural rigidity. The object of this study was to determine if the flexure behavior of uniform FRC beams with restrained or simply supported ends and various length/depth (L/d) aspect ratios could be more accurately modeled by correcting for shear. Experimental results were compared with three analytical models. All models were accurate at high L/d ratios, but the shear-corrected model was accurate to the lowest, more clinically relevant, L/d values. In this range, more than 40% of the beam deflection was due to shear.

Hand‐Modelled Composite Prostheses after Resection of Peri‐Acetabular Bone Malignancies

Purpose: To improve function after pelvic resection involving the acetabulum, using an anatomic composite implant built with screws and cement. Material and method: Since 1990, 66 patients with peri-acetabular bone malignancies have been treated by extensive resection followed by hand-modelled innominate prosthesis with partially constrained total hip prosthesis. The hand-modelled innominate prosthesis was made of a titanium cup, a set of long titanium screws and two or three packs of gentamycine-loaded cement. Results: Many postoperative complications were observed: deep infection (14%), hip prosthesis dislocation (25%) and local recurrence (15%). Sixteen patients (25%) had to be reoperated. Nevertheless, at last follow-up, 62 patients still had composite prosthesis. The mean functional result, rated according to a modified Enneking's staging system, was 80% with unlimited walking without support, average hip flexion 100°, length discrepancy less than 1 cm. Discussion: These results were similar to those described in the literature for custom-made innominate prostheses and much better than those of alternative reconstructive procedures. Hand-modelled composite prostheses are cheaper, easier, more adaptable and enables better anchorage than custom-made prostheses. Such a procedure can be used even after total iliac wing resection. Conclusion: The advantages of such a procedure plead for its extensive use after acetabular resection. But long-term follow-up is necessary to validate indications.

The design and fabrication of fiber-reinforced implant prostheses

The use of fiber composite technology in the creation of metal-free implant prostheses may solve many of the problems associated with a metal alloy substructure such as corrosion, toxicity, complexity of fabrication, high cost, and esthetic limitations. Laboratory and clinical research evaluating glass fiber-reinforced composite prostheses used to restore and replace teeth has shown that these materials exhibit excellent mechanical properties and can form a chemical bond to resin-based veneer materials such as those used in the fabrication of certain types of implant prostheses. Two different designs of fiber-reinforced composite implant prostheses have been developed and placed in human subjects. One design (screw-retained, retrievable prosthesis) is used with implant abutments that allow for screw-retained prostheses; the other design is used with abutments that retain prostheses with a luting material. Both designs are described in this article. The prostheses have functioned well in a small group of preliminary subjects, but clinical trials with larger subject populations are needed to more completely evaluate the potential of fiber-reinforced composites in implant prosthodontics. (J Prosthet Dent 2002;88:449-54.)

Reconstructions majeures de la hanche par association de prothèses et d’allogreffes (résultats à long terme de 34 prothèses composites)

Reconstruction after major resections of malignant tumors can be achieved by association of prostheses and of massive allografts. In 34 patients, we could reconstruct: the proximal femur in 21 cases, after an average resection of 180 mm, with a "composite" allograft prosthesis (with a bone graft around the stem) or a "composite and combined" allograft prosthesis (in which the femur allograft was associated with the trochanteric tendons, to facilitate the reinsertion of the glutei muscles); 10 hemipelvis in which the cup was inserted in an hemipelvic allograft; 3 proximal femurs and acetabulum (with composite cups and stems). In comparison with metallic reconstruction prostheses, composite prostheses improved function, limited complications, and increased longevity. The association of allografts and prostheses not only allows reconstructions which could be hardly achieved with only prostheses (especially for the pelvis), but also improves functional result and longevity, thanks to the biological fixation of the osseous and tendinous allografts. Considering our 15 years follow up in oncology, we have now extended these procedures to the major bone losses of the femur and pelvis following iterative revisions of standard prostheses for arthritis.

Healing process induced by three composite prostheses in the repair of abdominal wall defects

Healing process induced by three composite prostheses in the repair of abdominal wall defects

Percutaneous implantation of subcutaneous prosthetic ureters: long-term outcome.

We have used an extra-anatomic subcutaneous alloplastic ureteral replacement initially to bypass ureteral obstruction secondary to advanced pelvic malignancies in patients with a short life expectancy. Following the encouraging preliminary results, our list of indications has broadened to include complex benign ureteral strictures. We herein report the long-term outcome. A series of 35 subcutaneous prosthetic ureters were implanted percutaneously in 27 patients (19 unilateral and 8 bilateral) to bypass extrinsic ureteral obstructions. The nature of obstruction was neoplastic in 22 patients and benign in 5. A composite prosthesis, consisting of two coaxial tubes--internal pure smooth silicone covered by coiled e-PTFE--has been designed to serve as the ureteral replacement. This tube is inserted percutaneously into the renal pelvis, tunnelled subcutaneously, and introduced through a small suprapubic incision in the bladder. All patients were followed to date or until death from tumor. The mean follow-up was 6.3 months for the deceased patients and 47 months for the surviving ones, the longest follow-up being 84 months. No operative or immediate postoperative deaths were observed. Initial difficulty in placing the prosthesis was encountered in 5 of the 27 patients (19%). Secondary parietal complications occurred in 8.5% of cases (3/35). The prosthetic ureter had to be removed in one patient because of skin erosion. Return to a standard percutaneous nephrostomy was needed in two patients because of local tumor progression with bladder fistulae. Five patients are alive with the prosthesis in place and a follow-up as long as 84 months without encrustation, infection, obstruction, or skin problems and with normally functioning kidneys. The subcutaneous urinary diversion using a silicone-PTFE prosthesis is an efficient and minimally invasive way to bypass malignant or complex benign obstructions of the ureters that otherwise would necessitate permanent nephrostomy drainage.

Parietal reinforcement prostheses: an original intraperitoneal experimental study

The use of prosthetic materials is widely accepted for incisional and complex hernias, but the type of prosthesis in the abdominal wall still arouses acute controversy. We report an original experimental protocol testing three material placed intraperitoneally in the rat: a polyester mesh, a compound prosthesis (juxtaposition of a polyester mesh and a mesh of polyglactin 910) and a composite prosthesis (where fibers of polyester and polyglactin 910 were woven in the same mesh). There were two main criteria for assessment: the biologic tolerance to the material on the one hand, characterized histologically by the ratio of the surface of fibrosis to the surface of the inflammatory granuloma in contact with the material, and the nature of the adhesions between prosthesis and abdominal wall and the intraperitoneal viscera on the other. Statistical analysis of the results led to a preference for the homogeneous polyester prosthesis, compared with compound and composite prostheses (polyester and polyglactin 910) and to abandonment of the intraperitoneal site for insertion of such materials.

Replacement of the proximal aorta and aortic valve using a composite bileaflet prosthesis and gelatin-impregnated polyester graft (Carbo-Seal): Early results in 143 patients

Objective: We report the combined early results from two centers in the United Kingdom using a composite conduit consisting of a bileaflet mechanical valve incorporated into a gelatin-impregnated, ultra-low porosity, woven polyester graft (Carbo-Seal; Sulzer Carbomedics, Inc, Austin, Tex). Methods: Between August 1992 and March 1997, 143 patients underwent aortic root replacement with the Carbo-Seal composite prosthesis. The indication for surgery was acute type A dissection in 31 (22%), chronic type A dissection in 9 (6%), ascending aortic aneurysm without dissection in 100 (70%), and false aneurysm of the ascending aorta in 3 (2%). Twenty-seven patients (19%) had undergone previous sternotomy, and 40 (28%) were seen as emergencies. Concomitant procedures were performed in 38 (27%), including 18 aortic arch or hemiarch replacements. Total follow-up is 270 patient-years. Follow-up is 100% complete. Results: The early (30-day) mortality was 7% (10 patients). Permanent neurologic events occurred in 2%. At a mean follow-up of 23 months, 94% of survivors were in New York Heart Association functional class I. Freedom from reoperation was 97.2% ± 1.6% (1 standard error [1 SE]) at 12 months and 95.7% ± 2.2% at 48 months. Including early mortality, survival was 90.1% ± 2.6% at 12 months and 83.1% ± 3.5% at 48 months. Conclusions: Aortic root replacement with use of the Carbo-Seal prosthesis can be undertaken with a relatively low early mortality and morbidity. A low reoperation rate and high intermediate-term survival can be expected, but continued follow-up is needed to determine the long-term efficacy of this prosthesis. (J Thorac Cardiovasc Surg 1999;118:1014-20)

Aortic root replacement with the Carboseal composite graft: 7-year experience with the first 100 implants

Background. Aortic root replacement remains a challenging surgical procedure. A variety of techniques and prosthetic devices have thus far been used. In order to assess the performance of the Carboseal (Sultzer Carbomedics, Inc, Austin TX) composite graft, review of the experience with composite root replacement was undertaken.Methods. Between January 1979 and December 1998, 273 patients underwent composite aortic root replacement. One-hundred-six received the Carboseal composite prosthesis (group 1) and 84 other types of composite grafts (group 2). Demographic and operative variables were similar in the 2 patient groups, except for an older mean age in group 1 (58 ± 12 versus 50 ± 12 years, p = 0.001).Results. Operative mortality was lower in group 1 patients (3 of 106, 3% versus 10 of 84, 12%, p = 0.04). Follow-up of survivors was longer in group 2 due to more recent adoption of the Carboseal grafts (93 ± 57 versus 36 ± 23 months, p = 0.01). Late mortality was higher in group 2 (3 of 103, 3% versus 13 of 74, 18%, p = 0.04), with higher prevalence of prosthetic-related complications (2 of 103, 2% versus 12 of 74, 15%, p = 0.002). Reoperation was more prevalent in group 2 (1 of 103, 1% versus 5 of 74, 8%, p = 0.04), and limited to patients having root replacement using the inclusion technique. Functional status of survivors was comparable in the 2 groups (83 of 103, 80% versus 45 of 74, 61% of patients in New York Heart Association class I, p = 0.1).Conclusions. Aortic root replacement using the Carboseal composite graft offers excellent long-term results, with negligible prevalence of prosthetic-related complications. Superior performance compared to other available composite grafts in the present series may be influenced by more recent adoption of the Carboseal conduit and concomitant uniform adoption of coronary button technique.

Preliminary Study on Composite Hip Prostheses Made by Resin Transfer Molding

Metal hip implants used in arthroplastic surgery have an elastic modulus which is an order of magnitude higher than the modulus of the surrounding cortical bone. Therefore the metal implant assumes most of the applied loads resulting in resorption of the unloaded bone material by the human body which can cause the impant to loosen. In addition, patients may experience allergic reaction due to the release of metal ions or particles caused by friction, wear or enzymatic effects. Composite materials offer potential benefits such as tailorable mechanical properties, enhanced damage tolerance and fatigue life and improved biocompatibility. Based on structural analysis and mold filling simulation, prototypes of a hip prosthesis were manufactured using the resin transfer molding process. The preform of the prototype consists of braided high strength carbon fiber socks which are wrapped around a balsa wood insert. Two fiber architectures with different fiber angles (20° and 15° relative to the stem axis) were used. The maximum average fiber volume fraction obtained was about 38%. The mechanical performance of the composite hip prostheses was evaluated by static, fatigue and impact testing. Static testing verified that composite prostheses with the 20° braid carbon fiber preform exhibited an ultimate load of 7.5 kN, which is ten times the body weight of a 75 kg person. Fatigue testing showed that two million load cycles can be performed with a maximum load of 5 kN for the implants with the 20° reinforcement and 5.5 kN with 15° preform. The use of this type of prostheses in press fit applications was verified by conducting impact tests, simulating the hammer blows executed during the surgery. The study lays out the scientific base for a new manufacturing technique for composite hip prostheses using the resin transfer molding process and shows that prostheses with similar stiffness to the surrounding bone can be manufactured. All steps of the development cycle, including design, structural analyis, mold filling simulation, manufacturing and evaluation of performance, were performed on a basic level. The mechanical performance, especially fatigue and impact resistance were found to be excellent. The design of the implant and the mold need further revision in order to enhance mechanical performance, to ease manufacturing and to improve quality.

Computer-aided manufacturing of implants for the repair of large cranial defects: An improvement of the stereolithography technique

The objective of this study is to demonstrate the utility of geometric modeling in cranioplasty; in other words, to use geometric modeling to generate a prototype that will be used as the base structure of a composite prosthesis for covering cranial defects. This geometric model is easy to manipulate and can be modified. To achieve this goal, the top surface of a cranial bone flap is digitized using a portable coordinate measurement machine. Intentionally; a sub-surface of the bone flap, representing the skull defect, was not digitized. A geometric model of the bone flap is generated that includes the undigitized region. With the technique described in this paper the authors generated the geometric model of the undigitized region (the skull defect). The geometric model of the bone flap is further manipulated and a series of conical cavities are introduced. Prototypes of the geometric models are manufactured using stereolithography. The clinical implications of this technique are discussed. [Neurol Res 1999; 21: 281-286]

Towards the development of composite synthetic vascular prostheses

Towards the development of composite synthetic vascular prostheses

Composite hip prosthesis design. II. Simulation.

An investigation was performed to study the mechanical performance of fiber-reinforced composite hip prostheses. In Part I of the study, a three-dimensional finite element code was developed for analyzing a composite hip prosthesis in a femur. The material properties of the composite were treated as anisotropic and inhomogeneous while the properties of the femoral bone were treated as anisotropic and homogeneous. All the materials were assumed to behave linear-elastically. Thermoplastic graphite/PEEK material was selected for the study. No slippage was assumed at the interface between the implant and the surrounding femoral bone. In Part II, numerical simulations were performed using the code to study the performance of a composite prosthesis in the femur. The stress/strain distributions, micromotions, and strain energy density of the surrounding femoral bone were evaluated and found to be related to initial fixation and long-term stability of the prosthesis in the femur. Numerous fiber orientations were studied, and the results of the calculations were compared with those generated from a prosthesis made of cobalt chrome and Ti-6Al-4V titanium alloys. Based on the analysis, it was shown that compared to conventional metallic implants more favorable stresses and deformations could be generated in the femur using composite implants. In addition, by changing fiber orientations according to femoral loads, a composite implant could be designed specifically for the left or the right femur.