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PubMedDate not supplied

Experimental reconstruction of the intrathoracic trachea using a new prosthesis made from collagen grafted mesh.

Intrathoracic tracheal replacement was performed in dogs using a tracheal prosthesis we had constructed from mesh. The prosthesis consists of Marlex mesh (polypropylene) reinforced with a continuous polypropylene spiral, and is grafted and coated with pig collagen (Types I and III). Complete surgical resection of the mediastinal trachea was performed in seven adult mongrel dogs. In 1 dog, a 4 tracheal ring segment (2 cm) was resected and replaced with a 3 cm prosthesis, and in 6 dogs, a 7 to 8 tracheal ring segment (4 cm) was resected and replaced with a 5 cm prosthesis. In the latter six dogs, a silicone tube was temporarily inserted into the replacement, and removed by bronchoscopy one month after surgery. In one dog that received a 4 cm replacement, we added omentopexy around the reconstructed trachea. The prostheses in all dogs were promptly infiltrated by surrounding tissue and incorporated by the host trachea. No dehiscence or air leakage was observed after surgery. Mild luminal stenosis was evident in one dog, and partial exposure of the mesh (ulceration) was observed in five dogs within an observation period of 3 to 26 months. However, in the dog that received omentopexy after tracheal reconstruction, no stenosis or ulceration was observed, and the luminal surface seemed lustrous even after 6 weeks. Formation of respiratory epithelium, which lined the prosthetic lumen, was seen to various degrees: in the 2 dogs killed 12 months and 26 months after surgery, confluent epithelization was confirmed histologically from the upper to the lower anastomosis of the prosthesis. The tracheal prosthesis is useful for the repair of intrathoracic tracheal defects and shows promise for clinical application with further investigation.

Animals↗
PubMedDate not supplied

A new porous tracheal prosthesis sealed with collagen sponge.

We have designed a new tracheal prosthesis to overcome problems with an earlier device, which included stenosis and exposure of its constituent mesh. A polypropylene mesh cylinder, reinforced with a polypropylene spiral, is sealed with collagen sponge made from porcine dermal collagen. Using this prosthesis, we performed cervical tracheal reconstructions on 11 dogs. Three dogs died within 3 months of reconstruction. Their causes of death were anesthetic accident, diarrhea, and suffocation, respectively. Bronchoscopically, the inner surface of the prosthesis was almost covered with host tissue by 2 months. However, in one dog, a relatively large area of the mesh was exposed in the tracheal lumen at 6 months; a smaller area was exposed in two other dogs. The appearance of the inner surface rapidly became lustrous, and central stenosis was not significant, even after 12 months. Histologically, an incomplete epithelial lining at 6 months was seen on the reconstructed surface and included ciliated columnar, cuboidal, and squamous epithelium. These observations have revealed that this prosthesis has high biocompatibility and the potential to overcome problems of stenosis of the prosthesis lumen. However, because ulceration persists with this prosthesis, additional improvement is needed to reduce the incidence of mesh exposure.

Animals↗
PubMed2003

The incudostapedial joint angle: implications for stapes surgery prosthesis selection and crimping.

OBJECTIVE: To evaluate the role of the incudostapedial joint (ISJ) angle in stapes prosthesis size selection and crimping. METHODS: The ISJ of 13 cadaveric human temporal bones were photographed, then measured using computer-aided design software. The relationship of ISJ angle to prosthesis length was modeled. A literature review evaluated factors contributing to stapedectomy failure. RESULTS: The mean ISJ angle was 93.0 degrees (SD = 8.3 degrees ) (range, 75.0 degrees -104.0 degrees ). The mean ISJ angle deviation from 90 degrees was 7.35 degrees (SD = 4.45 degrees ) (range, 0.3 degrees -15.0 degrees ). The mean distance along the incus accessible for prosthesis placement was 3.21 mm (SD = 0.55 mm) (range, 2.00-4.00 mm). CONCLUSIONS: Significant deviation of the ISJ angle from 90 degrees was found (P <.0001). The length along the incus accessible for prosthesis placement was sufficient to result in errors in prosthesis size selection and crimping with only small variations in the ISJ angle. Incorrect prosthesis sizing and crimping are frequently associated with stapedectomy failure. Variations in ISJ anatomy should be considered when selecting stapes prostheses lengths and may affect crimping technique.

Culture Techniques↗
PubMed1976

Haemolysis after mitral valve replacement with the Björk-Shiley and the Lillehei-Kaster disc valve prosthesis.

The present study reports on the incidence and degree of intravascular haemolysis in 33 patients with Björk-Shiley tilting disc prosthesis and in 34 patients with Lillehei-Kaster pivoting disc valve prosthesis in the mitral position examined 12 to 24 months after the operation. Serum haptoglobin, serum lactate dehydrogenase, serum bilirubin, and haemoglobin estimations were performed. Significant haemolysis was detected in 85 per cent of the patients. Haptoglobin was absent or reduced in 72 per cent, while raised values for serum lactate dehydrogenase were found in 43 per cent. The increase in lactate dehydrogenase was moderate and showed no correlation with blood flow through the prosthesis or with the gradient across the prosthesis. Most patients had normal haemoglobin and normal serum bilirubin values. Although intravascular haemolysis was of little clinical significance, the increase in lactate dehyrdrogenase was significantly higher in patients with the Lillehei-Kaster prosthesis than in patients with the Björk Shiley prosthesis, indicating a slightly shorter red cell lifespan in the former group. The possible reasons for the difference between the two groups are discussed.

Adult↗
PubMed1986

The ossicle-cup prosthesis: five years later.

The ossicle-cup prosthesis is a semibiologic prosthesis that incorporates a synthetic portion into the remaining (or transplant) ossicle. This assembly is positioned on the stapes capitulum, with the synthetic cup forming a dynamic joint. During 1978, 114 patients underwent surgical procedures in which an ossicle cup prosthesis was used. After 1 year 84% of these patients were within 20 dB of their preoperative bone hearing levels. Patients with a concurrent mastoidectomy did worse than those who underwent only a tympanoossiculoplasty. Five years later, 74% of the successful cases were still within 20 dB of the preoperative hearing levels. Eighteen patients underwent a revision surgical procedure to regain hearing. The postoperative hearing results at 1 year were 50% within 20 dB. The causes of failure included further ossicle necrosis (28%), a laterally healed tympanic membrane (39%), and fixation of the prosthesis (33%). Extrusion of the prosthesis during the 5-year period was between 1% and 2%. Overall, the ossicle cup prosthesis has proved to be a stable assembly, easy to revise, and longlasting. Once successful, three of four cases will retain successful hearing for more than 5 years.

Adolescent↗
PubMed2003

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.

Animals↗
PubMed2000

The design and testing of a composite lower limb prosthesis.

In unilateral lower limb prosthetic gait, the intact limb, together with the hip on the affected side, strive to compensate for the loss of the missing below-knee musculature. The resultant abnormal gait patterns can eventually lead to pathologies of the spine and other joints. The aim of this research was to design a trans-tibial dynamic elastic response (DER) prosthesis which could simulate the power generation and absorption properties of an intact foot and shank segments. A carbon fibre sickle-shaped prosthesis was developed in which the strain energy from the early part of the stride was stored, and was released again at the point of take-off, to simulate the action of the missing musculature. Stress analysis techniques were used in the design of the prosthesis, for the purposes of computing and maximizing the strain energy of the elements. A force transducer was designed into the prosthesis to verify the analysis. Video motion analyses of the prosthesis were carried out in order to determine the most appropriate shape that would reduce gait asymmetries. The research shows that biomechanical techniques, together with good engineering design and the selection of modern materials, can lead to a prosthesis which approaches the function of a natural foot.

Artificial Limbs↗
PubMed2001

In vitro evaluation of a malleus head to stapes head 'incus replica' prosthesis.

An ossicular prosthesis produced by making a mould from a cadaveric incus and injecting ionomeric cement into it (incus replica prosthesis, IRP) has been cemented to the malleus head and stapes head and evaluated in fresh human temporal bones using a laser vibrometer. Stapes velocity was recorded under acoustic stimulation and foot plate displacements were derived. Fourteen frequencies between 125 Hz and 8000 Hz have been used. Measurements were made with the ossicular chain intact, following removal of the incus, with the prosthesis cemented to the malleus, but not the stapes, and with the incudo-stapedial joint cemented. In a second series of experiments the performance of the IRP was compared with that of a Causse partial ossicular replacement prosthesis, using the same experimental set-up. The results indicate that the prosthesis performs almost as well as the intact ossicular chain and that cementing the incudo-stapedial joint gives better sound transmission than leaving it uncemented. In addition the IRP outperforms the conventional partial ossicular replacement prosthesis.

Bone Cements↗
PubMed2003

Conversion of a fused knee with use of a posterior stabilized total knee prosthesis.

BACKGROUND: Typically a hinged or condylar constrained prosthesis is recommended for total knee arthroplasty in a fused knee, to substitute for the absent or deficient collateral ligaments. The purpose of this study was to evaluate the stability and clinical results after the use of a posterior stabilized prosthesis in the conversion of a fused knee to a total knee arthroplasty. METHODS: Thirty-six patients (thirty-six knees) with a mean age of 39.2 years underwent conversion of a fused knee to a total knee arthroplasty with a posterior stabilized prosthesis. The mean duration of ankylosis had been 24.5 years. Clinical and radiographic evaluation was carried out preoperatively; at six weeks and three, six, and twelve months postoperatively; and annually thereafter. The mean duration of follow-up was 7.7 years. RESULTS: The mean preoperative Hospital for Special Surgery knee score of 60 points improved to 83.2 points at the final follow-up examination. Twenty-two knees were pain-free, and the remaining fourteen were mildly painful after prolonged walking. The mean amount of active flexion in the entire group was 77.7 degrees. The extension lag in the entire group averaged 12.5 degrees. Complications included necrosis of the skin edges in eighteen knees (50%), a rupture of the quadriceps tendon in two patients, and a pyogenic infection in two. No prosthesis required revision because of clinical or radiographic loosening. CONCLUSIONS: We believe that when the soft-tissue sleeves in a previously fused knee are carefully preserved intraoperatively, they can provide adequate stability after total knee arthroplasty with a posterior stabilized prosthesis. Therefore, we believe that use of that type of prosthesis is a reasonable alternative to the use of a more constrained implant in the treatment of this condition.

Adult↗
PubMed2000

In vitro evaluation of a novel prosthesis for laryngoplasty of horses with recurrent laryngeal neuropathy.

A prosthesis, composed of a steel cable and stress-reducing washers, was developed to prevent failure of laryngoplasty, a common treatment for horses affected by recurrent laryngeal neuropathy. Laryngoplasties were performed on 15 cadaveric larynges using a polyester suture on one side and the cable prosthesis on the other. Each prosthesis was distracted at a displacement rate of 20 mm/s using a servohydraulic materials testing machine until laryngoplasty failed. Distraction force and actuator displacement were recorded and analysed. All 15 laryngoplasties performed with a suture failed at the muscular process at a mean +/- s.d. force of 55.8 +/- 13.1 N. Six laryngoplasties performed with the cable prosthesis failed at the muscular process at mean force 219.6 +/- 125.0 N. In the other 9, the arytenoid cartilage was avulsed from the larynx at mean force 206.4 +/- 75.3 N, and the cable then tore through the muscular process at mean force 357.0 +/- 32.0 N. The difference in force required to cause failure of laryngoplasty was significant (P<0.0001). Although the prosthesis resisted substantially higher forces than did the suture, the effects of the prosthesis in vivo must be evaluated.

Animals↗
PubMed1978

Ideas on the suspension of the below-knee prosthesis.

Comparative studies with the PTB-suction prosthesis and the ordinary PTB prosthesis have provided opportunities to analyze and understand some functional differences in the suspension of below-knee prostheses. In a roentgenological study of the stump-socket contact signficantly less vertical displacement in the PTB-suction prosthesis has been shown. A study of the pressure variations in the suction socket verified the theory of the necessary pressure gradient in the PTB-suction socket. Added negative pressure by muscle action was also observed. An electromyographic study suggested a muscular activity pattern in the suction prosthesis similar to that of a normal leg, as a contrast to the ordinary PTB prosthesis where simultaneous contractions of antagonistic muscles seemed to be the usual pattern. The latter is interpreted as a defence reaction. An optimal prosthesis has been deduced. It shall have a soft prosthetic socket with a perfect fit, a suction, adhesion and friction fixation and a pressure gradient between the skin and the socket wall with minimum compression distally. The plaster casting shall be done in a downward modelling manner making available space for soft tissue without compression.

Amputation, Surgical↗
PubMed1999

A new alignment jig for quantification and prescription of three-dimensional alignment for the patellar-tendon-bearing trans-tibial prosthesis.

Clinically, it is hard to achieve and reproduce prosthesis alignment at will during daily prosthesis fitting. A new alignment jig was designed and developed to facilitate quantification and prescription of prosthesis alignment for patellar-tendon-bearing (PTB) trans-tibial prostheses. The alignment jig provided instantaneous readings of the three-dimensional orientation and position of the socket relative to the prosthetic foot in standardised units. The inter- and intra-tester errors of the alignment jig in measuring prosthesis alignment were evaluated and demonstrated to have good reliability. The alignment jig was recommended to be used clinically after the conventional dynamic alignment procedure to document the prosthesis alignment. Further application of the alignment jig for systematic evaluation of the effects of prosthesis alignment on gait for trans-tibial amputees is suggested.

Artificial Limbs↗
PubMed1981

Haemodynamic evaluation of the convexo-concave Björk-Shiley prosthesis in patients with narrow aortic annulus.

A late haemodynamic re-evaluation at rest and during exercise was performed in 22 patients with isolated aortic valvular disease and narrow aortic annulus, operated upon with the convexo-concave Björk-Shiley prosthesis. The 21 mm prosthesis had been inserted in 11 patients and the 23 mm one in the other 11 patients. Left ventricular pump function improved and was normalized in half of the patients. The mean systolic pressure difference across the 21 mm convexo-concave prosthesis was 16.2 +/- 8.1 mmHg at rest and 20.7 +/- 7.9 mmHg during exercise (32 +/- 10 watts). It was 14.9 +/- 6.0 mmHg at rest and 18.6 +/- 6.3 mmHg during exercise (34 +/- 156 watts) across the 23 mm convexo-concave prosthesis. Compared with the earlier investigated standard model Björk-Shiley prosthesis, the 21 mm convexo-concave version creates a lower resistance to blood flow (less than 0.01), whereas no such difference could be demonstrated in the two models of 23 mm tissue diameter. It was concluded that the new convexo-concave tilting disc valve constitutes an improvement over the standard model in the management of the narrow aortic annulus permitting insertion of a 21 mm prosthesis.

Adult↗
PubMed1998

[Traissac voice prosthesis. Apropos of 9 years experiences].

BACKGROUND: Long term results are discussed. PATIENTS: A retrospective study of 9 years (1/01/89, 1/01/98) concern 107 laryngectomized patients with 9 patients a part from this period, and 30% without prosthesis. Among 80 patients with prosthesis, 57% had received primary TEPs (tracheoesophageal puncture), 21% delayed primary TEPs and 22% secondary TEPs. Oesophageal voice is always learned with tracheoesophageal voice. RESULTS: We find a success rate (1 month) in 75% of cases, with a maximum follow up time of 8 years (the average is 3 years 1 month). We find a success rate with a long-term result in 66% of cases. Prosthesis removal exists in 30% of cases and oesophageal voice is successfull once out of 3 in this cases. Mean lifetime Traissac's prosthesis is 18 months. After removal, non closed fistulas can exist in 40% of cases, and surgery is always successful. DISCUSSION: Material Traissac's prosthesis explains extended lifetime. CONCLUSION: Traissac's prosthesis gave us satisfaction during a use of 8 years.

Equipment Failure Analysis↗
PubMed1976

Comparison of an EMG-controlled prosthesis and the normal human biceps brachii muscle.

An electromyographically-controlled elbow prosthesis, the "Boston arm", was tested with constant and sinusoidally-modulated inputs under different loading conditions. These tests were used to determine the frequency response of the EMG amplifier, the range of motor speeds, the force-velocity curve, and the frequency response of the prosthesis for cyclic movements. Human biceps muscle was tested during movements under similar loads, and under isometric conditions using random, electrical stimuli to determine its frequency response. The results were compared to evaluate the performance of the prosthesis and contrast its characteristics to those of the physiological system it replaces. The prosthesis minimizes quiescent power drain, and the possibilities of instability or "tremor" by employing velocity control, an overdamped mechanical system, and an electrical "dead-band". These factors limit the ability of the prosthesis to follow rapidly changing inputs or to move rapidly and accurately to a desired position. These comparisons should provide a useful supplement to the usual clinical evaluations, and a starting point for further improvements in prosthesis design.

Arm↗
PubMed2003

The Stout prosthesis: an alternate means of restoring speech in selected laryngectomy patients.

We discuss the effectiveness of the Stout prosthesis, a device that was developed more than 30 years ago to restore speech in postlaryngectomy patients. This prosthesis has not been previously described in the literature. The placement of this device entails the creation of a pharyngeal cutaneous fistula that extends to the musculature at the base of the tongue. The prosthesis is then used to connect the fistula and the stoma. Central to this discussion was our evaluation of a patient who had used the Stout prosthesis for 30 years. In this patient, the prosthesis produced excellent long-term voice production with minimal leakage of saliva or other liquids. We conclude that in light of the device's simplicity, low cost, and minimal maintenance requirements with regard to the fistula site, the Stout prosthesis should be considered as an alternative to the standard tracheosophageal puncture method for patients who are unable to comply with the latter's maintenance requirements and for those in poorly developed countries where costs and hygiene are paramount considerations. Moreover, because the Stout technique does not involve the esophagus and does not require invasive procedures around the stoma, it is also practical for patients who have esophageal rigidity or stomal problems.

Humans↗
PubMed2003

[Flexor tendoplasty with a tendon prosthesis for zone II flexor tendon injuries].

OBJECTIVES: We evaluated two-staged flexor tendoplasty with tendon prosthesis in patients with flexor tendon injuries in which conventional tendon grafting would fail to yield an acceptable result. METHODS: We performed flexor tendoplasty with tendon prosthesis in 37 hands of 31 patients (24 males, 7 females; mean age 23 years; range 4-46 years). Twenty-six patients had penetrating injuries, four had occupational injuries, and one patient had an electric burn. Preoperatively, all patients were evaluated according to the Boyes' classification. At the first stage, a silicone prosthesis, 4-6 mm in diameter was placed according to the patient's age and the recipient bed; after 3 to 5 months, silicone prosthesis was removed and flexor tendoplasty with a tendon graft was performed. The results were calculated according to the Strickland's formula. The mean follow-up period after the second operation was 37 months (range 12-80 months). RESULTS: The results were excellent in 11 hands (Strickland 75-100%), good in 15 hands (50-74%), moderate in nine hands (25-49%), and poor in two hands (0-24%), with a mean of 58%. Tenolysis was performed in seven patients at least four months after the second stage. Removal of the tendon prosthesis was required in one patient because of infection. CONCLUSION: Satisfactory results can be obtained with two-staged flexor tendoplasty with a tendon prosthesis in patients with joint injuries restricting finger movements, digital nerve injuries causing trophic changes in the finger, and multiple tissue injuries.

Adolescent↗
PubMed2005

[The evaluation of early and late results of using Codubix cranial prosthesis].

The filling of the cranial defect is an essential problem in neurosurgery on account of the necessity of brain protection as well as for cosmetic reasons. The aim of this study was to evaluate the direct and distant outcome after polypropylene-polyester Codubix prosthesis implantation. This research was based on the analysis of 41 patients treated surgically in the Department of Neurosurgery at the Jagiellonian University in Cracow between 1995-2004. All patients had the Codubix prosthesis implanted. The implantation was performed either synchronously or after the surgery which caused the cranial defect. Directly after the surgery proper healing of the prosthesis could be observed in all patients. The exception was one patient who died directly after the surgery but the cause of his death was not connected with the prosthesis implantation. Seven patients (17,1%) had the temperature temporarily elevated. Three had haematoma collection in the subgaleal space, one (2,4%) developed meningitis which was successfully treated with antibiotics, one (2,4%) suffered from temporary circulation disturbances of the scalp. The late evaluation was performed with help of a questionnaire to which 30 patients (73,2%) responded. The answer ranged 73,2% (30 patients). In this group 16 patients (53,4%) described the cosmetic effect as very good, 10 patients (33%) as good and 4 (13,3%) as unsatisfactory. The commonest reason for the critical note was the depression of the plate which happened to 3 patients. The other 3 patients complained about inappropriate profile of the plate causing the asymmetry of the cranial vault. Seven patients felt temporary pain in the postoperative scar, in one case the pain was took as the friction between the prosthesis and bone margin. Properly performed implantation of accurate bone prosthesis Codubix is safe and usually brings a good cosmetic effect. Direct complications are transitional and occur in the small percent of cases. Distant examinations show generally good therapeutic results but implanted Codubix requires suitable shape and careful fixation.

Adolescent↗