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PubMed1985

Deep neck abscess after tracheoesophageal puncture and insertion of a voice button prosthesis.

A deep neck abscess and cervical osteomyelitis developed in a 37-year-old laryngectomy patient 6 weeks after TE puncture and insertion of a voice button prosthesis. This complication resulted in voice prosthesis failure, multiple surgical procedures, 83 days of hospitalization while receiving parenteral antibiotics, and exposure to potentially fatal complications. Some factors contributing to this problem may include an improperly fitting prosthesis, rough insertion of the prosthesis, and altered tissue response to infection from radiation therapy and surgery.

Abscess↗
PubMed2001

Micromotion and dynamic fatigue properties of the dental implant-abutment interface.

STATEMENT OF PROBLEM: Clinical loading may result in micromotion and metal fatigue in apparently stable implant screw joints. This micromotion may contribute to tissue inflammation and prosthesis failure. PURPOSE: This study investigated dental implant screw joint micromotion and dynamic fatigue as a function of varied preload torque applied to abutment screws when tested under simulated clinical loading. MATERIAL AND METHODS: Fifteen noble alloy single-tooth implant restorations, each containing a hexed UCLA-style gold cylinder, were randomly assigned to 3 preload groups (16, 32, and 48 N.cm). Each group consisted of 5 implants (each 3.75 x 15 mm) and 5 square gold alloy abutment screws. A mechanical testing machine applied a compressive cyclic sine wave load between 20 and 130 N at 6 Hz to a contact point on each implant crown. A liquid metal strain gauge recorded the micromotion of the screw joint interface after 100, 500, 1,000, 5,000, 10,000, 50,000, and 100,000 cycles. Baseline data at 0 N.cm were collected before the application of the specified preload torque. RESULTS: The 16 N.cm group exhibited greater micromotion (P<.001) than both the 32 and 48 N.cm groups at all cycle intervals (2-way ANOVA, Tukey HSD). Micromotion of the implant-abutment interface remained constant (P=.99) for each of the preload groups through 105 cycles. CONCLUSION: Under the loading parameters of this study, no measurable fatigue of the implant-abutment interface occurred. However, dental implant screw joints tightened to lower preload values exhibited significantly greater micromotion at the implant-abutment interface.

Analysis of Variance↗
PubMed2006

[Clinical use of a voice prosthesis with a flap valve containing silver oxide (Blom-Singer Advantage), biofilm formation, in-situ lifetime and indication].

BACKGROUND: Fungal growth and the resulting leakage through an indwelling voice prosthesis remains the most frequent reason of prosthesis failure and renewal. In some patients leakage caused by fungal growth occurs in very short intervals (below 12 weeks in-situ lifetime) and causes frequent treatments and high costs. METHODS: The Blom-Singer(R) Advantage voice prosthesis is a new prosthesis type with a modified flange design, a flap valve containing 7 % silver oxide in the silicon matrix and is expected to be resistant against biofilm formation and fungal growth. PATIENTS: In a clinical trial we used the Blom-Singer(R) Advantage prosthesis in 33 patients with short in-situ lifetimes of their voice prosthesis and analysed the effects on in-situ lifetime and complications statistically. RESULTS: The clinical use of the Blom-Singer(R) Advantage prosthesis was similar to other types of indwelling voice prosthesis (Provox(R) II, Blom-Singer Indwelling(R)) and did not cause any special problems. Prosthesis specific side effects (i. e. allergy against silver oxide) did not occur. Statistical analysis of the aquired data showed an interindividually changing, but significantly longer in-situ lifetime for the Blom-Singer(R) Advantage prosthesis. The mean device lifetime increased from 36 days (median 36 days) to a mean lifetime of 110 days (median 87 days) with the use of the Blom-Singer(R) Advantage prosthesis. CONCLUSIONS: Using a voice prosthesis with a valve containing silver oxide can normalize and even increase the in-situ lifetime in patients with frequent changing procedures caused by fungal growth on the valve. Therefore we recommend the use of this type of voice prosthesis for those patients as reduction of costs and effort results.

Aged↗
PubMed1991

Endoprosthetic replacement for stage IIB osteosarcoma.

Over an eight-year period, 100 patients with IIB osteosarcoma have been managed. Eighty-one were treated with limb-salvage procedures, 78 of which involved reconstruction utilizing endoprostheses. Only 19 patients received amputation as the primary treatment for local control. Since 1984, all patients received preoperative and post-operative adjuvant chemotherapy. Those patients who received chemotherapy had a statistically significant improvement in five-year survival over those who did not (57% and 32%, respectively, p = 0.014). The functional results were good overall, with excellent results seen in distal femoral reconstruction. Twenty-eight of the 78 patients treated with endoprosthetic reconstruction experienced 30 complications (36%). Mechanical failure was the most common complication (10%) but was generally correctable. The local recurrence rate was 5% and the infection rate was 3%. Local complications were manageable. A statistical analysis revealed that the relative risk of patient death was 2.5 times higher than prosthesis failure for the 78 patients with endoprosthetic reconstruction. The intermediate-term results, with a median follow-up period of 43 months, remains encouraging.

Adolescent↗
PubMed2002

Structural alterations of prosthetic meshes in humans.

The use of prosthetic mesh in abdominal wall hernia surgery is a well-accepted practice. What is not settled, however, is the type of prosthesis that best suits the purpose. The narrow choice today means a prosthesis of polyester or polypropylene. These are available in many designs, configuration of weave, thickness of weave and strand, and size of pore. There has been a pervasive feeling that these materials "shrink". To what extent they do has not been accurately defined. This study was designed to measure such "shrinkage". Interestingly, our measurements revealed that prosthetic meshes could "expand" as well as "shrink". The extent to which they do varies between -40% and 58.5%. Whereas it was felt that fibrocyte activity and its eventual scar formation accounted for the "shrinkage" of the mesh, we have discovered that structural alterations in the size of the mesh pores can be affected by distilled water, saline, blood, formalin, bleach, as well as in vivo implantation. Prosthetic meshes are, therefore, not the inert materials they are claimed to be and can expand as well as shrink. We have, unfortunately, not been able to correlate the degree or direction of change to any known parameter.

Adult↗
PubMed2002

Early and late complications associated with transcatheter occlusion of secundum atrial septal defect.

OBJECTIVES: The goal of this study was to report the early and late complications experienced in atrial septal defect (ASD) transcatheter closure. BACKGROUND: Atrial septal defect transcatheter occlusion techniques have become an alternative to surgical procedures. A number of different devices are available for transcatheter ASD closure. The type and rate of complications are different for different devices. METHODS: Between December 1996 and January 2001, 417 patients (mean age: 26.6 +/- 19 years) underwent transcatheter occlusion of secundum type ASD. Complications were categorized into major and minor. Two different devices were used: the CardioSEAL/STARFlex in 159 patients and the Amplatzer septal occluder in 258 patients. RESULTS: Thirty-four patients experienced 36 complications during the hospitalization (8.6%, 95% confidence interval: 6.1% to 11.1%). Ten patients underwent elective surgical repair because of device malposition (three patients) or device embolization (seven patients). Twenty-four patients experienced 25 minor complications: unsatisfactory device position or embolization. Devices were retrieved using a gooseneck snare and/or a basket; 11 patients experienced arrhythmic problems. Other complications were: pericardial effusion, thrombus formation on the left atrial disc, right iliac vein dissection, groin hematoma, hemorrhage in the retropharynx and sizing balloon rupture. Two patients had late complications: peripheral embolization in the left leg one year after implantation of an Amplatzer device and sudden death 1.5 year later. CONCLUSIONS: Our series of patients with ASD by transcatheter occlusion shows that the procedure is safe and effective in the vast majority of cases. To further reduce the complications rate, the criteria of device selection according to ASD morphology and some technical tips during implantation are discussed.

Adolescent↗
PubMed2001

Cervical disc prosthesis in humans: first failure.

STUDY DESIGN: Prospective preliminary trial of a cervical disc prosthesis. OBJECTIVE: To study the feasibility, efficacy in maintaining intervertebral mobility, and complications of a low-profile disc prosthesis implanted after single-level cervical discectomy. SUMMARY OF BACKGROUND DATA: Since studies reported by Baba et al, there is fear that degeneration of the intervertebral disc levels adjacent to cervical arthrodesis may be exacerbated by this arthrodesis. For this reason, several cervical prostheses have been designed as an alternative to arthrodesis. None of these prostheses, some of which are bulky, has been shown to be efficacious. METHODS: Five women and five men (average age, 36 years) underwent implantation of the present disc prosthesis after single-level discectomy. The discectomy was performed for cervical disc herniation that resulted in cervicobrachial pain for more than 3 months. None of the patients exhibited intervertebral instability on bending films. Preoperative magnetic resonance studies showed a noncontained disc herniation in all 10 patients and osteophytes in 2 of the patients. RESULTS: The cervicobrachial pain resolved in all 10 patients. Intense neck pain developed in 1 patient who underwent revision surgery to remove the prosthesis and perform an arthrodesis. Another patient developed neck pain but refused the proposed revision operation. Bending films showed mobility of the intervertebral space containing the prosthesis in both of these patients. In the 8 patients who remained pain free after the operation, lateral bending films at follow-up found no mobility of the implanted disc level. Five of these eight patients had circumferential fusion, 2 had posterior fusion, and 1 had anterior fusion. CONCLUSION: This prosthesis failed to achieve the desired effect because the intended mobility failed to persist in 8 of the 10 patients and pain developed in the other 2 patients, in whom the mobility persisted.

Adult↗
PubMed1987

Experience with St. Jude Medical valve prosthesis in children. A word of caution regarding right-sided placement.

Thirty-six children aged 6 months to 18 years, underwent insertion of 37 St. Jude Medical cardiac prostheses. In 20, the valve was placed in the aortic or mitral position, and in 16 in the pulmonary or tricuspid position. There was one (2.8%) hospital death. All patients received maintenance doses of salicylates and dipyridamole after the operation. Follow-up data are available for all patients for 12 to 24 postoperative months. There was no incidence of valve dysfunction or thromboembolic complication in any of the 20 patients with valves in the systemic (left) side of the circulation, and all manifested improvement in their functional class. In contrast, six (37%) of the 16 patients with valves in the pulmonary (right) side of the circulation developed dysfunction of the prosthesis 1 to 6 months after insertion. Prosthesis failure was associated with fibrous tissue growing into the struts, leading to leaflet immobilization. At 2 years, the actuarial functional life was 100% for mitral and aortic valves and 70% for pulmonary and tricuspid valves. The data illustrate the excellent hemodynamic function of the St. Jude Medical valve in children. The absence of thromboembolic complications warrant continued implantation of the prosthesis in the left side without warfarin anticoagulation therapy, but the high incidence of valve dysfunction in the pulmonary position does not justify its continued use in the right side.

Adolescent↗
PubMedDate not supplied

Finite element analysis study of the effect of superstructure material on stress distribution in an implant-supported fixed prosthesis.

This study used three-dimensional finite element analysis to investigate the effect of three different occlusal surface materials (resin, resin composite, and porcelain) and four different framework materials (gold, silver-palladium, cobalt-chromium, titanium alloys) on the stress distribution in a six-implant-supported mandibular fixed prosthesis and surrounding bone. A total of 172 N vertical load was distributed over the entire occlusal surface of the finite element model. Generated stress values were calculated in the occlusal surface material, framework, prosthesis retaining screws, implants, and surrounding cortical and spongy bones. The results obtained demonstrated that using a prosthesis superstructure material with a lower elastic modulus (1) did not lead to substantial differences in stress patterns nor in values at the cortical and spongy bones surrounding the implants; and (2) concentrated stresses in the retaining screws for the prosthesis and thus increased the potential risk of prosthesis failure. For the single loading condition investigated, the optimal combination of materials was found to be cobalt-chromium for the framework and porcelain for the occlusal surface.

Acrylic Resins↗
PubMedDate not supplied

Thrombotic disc impediment in a Medtronic-Hall aortic valve prosthesis diagnosed by Doppler echocardiography followed by successful reoperation.

A case with impeded disc movement caused by thrombus formation in a Medtronic-Hall aortic valve prosthesis is reported. A correct diagnosis, including both mechanism and severity of the prosthesis failure, was established by Doppler echocardiography. The patient was promptly referred for surgery without invasive or other supplementary investigations.

Aortic Valve↗
PubMed2002

The Lichtenstein repair in 2002: an overview of causes of recurrence after Lichtenstein tension-free hernioplasty.

Lichtenstein tension-free hernioplasty began in 1984. Based on our own mistakes, in the late 1980s, we established a set of key principles and reported the causes of our recurrences. Recently, other authors analyzing the causes of their own recurrences with tension-free repair are drawing the same conclusions. This indicates that others are repeating our previously reported mistakes. To prevent recurrence, the mesh size was increased to 7.5x15 cm to extend well beyond the boundary of the inguinal floor and give the mesh a dome-shaped laxity to compensate for the increased intra-abdominal pressure and mesh shrinkage. Wide extension of the mesh beyond the inguinal floor and the dome-shaped laxity of the mesh served to further reduce recurrence rate. Following the key principles of the Lichtenstein tension-free hernioplasty, which can be facilitated by using a recently developed prosthesis that addresses all the key principles of the procedure, achieves the best result.

Abdominal Wall↗
PubMed1998

Lipid uptake in expanded polytetrafluoroethylene vascular grafts.

PURPOSE: The mechanisms of vascular prosthesis failure are reported to be associated, in part, with an atherosclerotic degenerative process that is related to an abnormal lipid infiltration. The lipid uptake in expanded polytetrafluoroethylene (ePTFE) vascular grafts was reproduced in vitro, and the effect of time on the permeability of these prostheses was studied. METHODS: Water permeability tests were carried out under dynamic flow conditions at various hydrostatic pressures. Lipid uptake was simulated by circulating a phosphatidylcholine suspension inside an expanded Teflon prosthesis under pulsatile or continuous transmural pressure ranging between 80 mm Hg and 180 mm Hg, at a flow rate of 500 mL/min and 2000 mL/min, for a duration ranging from 2 hours to 1 month. RESULTS: Water permeability tests indicated that under hydrostatic pressures of 180 mm Hg and 300 mm Hg, water percolated through the prosthesis wall after an exposure of 720 minutes and 75 minutes, respectively. After exposing the prostheses to the lipid dispersion under the various flow conditions, the fluid convection through the wall occurred. Preferential convection pathways with a constant periodicity were observed across the length of each prosthesis and were, therefore, associated with regularly spaced perforations depicted in the structure of the devices. Phospholipids gradually agglomerated within the prosthesis wall, allowing a restrictive molecular mobility. Infrared spectroscopy results indicated that the lipid uptake depended on the transmural pressure and time of exposure. CONCLUSION: The occurrence of the membrane permeability may be associated with the dilatation and plastic deformation of the prosthesis. Lipid uptake occurs in ePTFE grafts after an aggressive kinetic process.

Blood Vessel Prosthesis↗
PubMedDate not supplied

Aorto-iliac reconstruction with Dacron double velour.

Dacron double velour grafts were evaluated in an animal preparation and utilized in 318 patients undergoing elective aortic reconstruction for aneurysmal and occlusive disease. Dacron double velour forms an adherent inner lining, preclots easily, is soft, pliable and easy to handle and suture. Clinical studies revealed excellent patency with a low incidence of prosthesis related complications. No clinical evidence of overt prosthesis failure, dilation, aneurysm formation, or pseudointimal embolization occurred during an average follow-up of 2.3 years.

Actuarial Analysis↗
PubMed1997

Candida glabrata prosthesis infection following pyelonephritis and septicaemia.

Candida glabrata is a well-known cause of lower urinary tract infections. Systemic infections caused by this organism are less common, but have increased dramatically in recent years. Prosthesis infection caused by C. glabrata is extremely rare. We report a case of prosthesis failure due to C. glabrata 5 y after candidaemia and pyelonephritis caused by this organism. The same C. glabrata strain was isolated from both infections, as confirmed by the random amplified polymorphic DNA (RAPD) method.

Antifungal Agents↗
PubMed2003

No bias of ignored bilaterality when analysing the revision risk of knee prostheses: analysis of a population based sample of 44,590 patients with 55,298 knee prostheses from the national Swedish Knee Arthroplasty Register.

BACKGROUND: The current practice of the Swedish Knee Register is not to take into consideration if one or both knees in a patient are subject to surgery when evaluating risk of revision after arthroplasty. Risk calculations are typically done by statistical methods, such as Kaplan-Meier analyses and Cox's proportional hazards models, that are based on the assumption that observed events are independent, and this is rarely appreciated. The purpose of this study was to investigate if ignoring bilateral operations when using these methods biases the results. METHODS: The bias of not taking bilateral operations into account was investigated by statistically analysing 55 298 prostheses in 44 590 patients, undergoing knee arthroplasty surgery in Sweden during 1985-1999, using traditional proportional hazards analysis, which assumes that all observations are independent, and a shared gamma frailty model, which allows patients to contribute repeated observations. RESULTS: The effect of neglecting bilateral prostheses is minute, possibly because bilateral prosthesis failure is a rare event. CONCLUSION: We conclude that the revision risk of knee prostheses in general can be analysed without consideration for subject dependency, at least in study populations with a relatively low proportion of subjects having experienced bilateral revisions.

Adolescent↗
PubMed2003

Long-term results of Bentall composite aortic root replacement for ascending aortic aneurysms and dissections.

STUDY OBJECTIVES: The aim of this study was to evaluate the early and long-term outcomes in patients undergoing aortic root replacement (ARR) with the Bentall procedure. DESIGN: Retrospective study. SETTING: Cardiothoracic surgery unit. PATIENTS AND METHODS: Between January 1986 and January 2002, 72 patients (mean age 58.3 +/- 12.4 years, 81.9% males) underwent ARR by means of a Bentall operation. Annuloaortic ectasia was the most frequent cause of aortic disease in this series of patients (31 patients; 43.1%), followed by type A dissection (19 patients; 26.3%), atherosclerotic aneurysm (18 patients; 25.1%), and poststenotic dilatation (4 patients; 5.5%). Nine patients (12.5%) had Marfan syndrome, and 10 patients (13.8%) underwent a concomitant replacement of the aortic arch. Follow-up ranged from 2 to 192 months (mean [+/- SD], 86.6 +/- 23.8 months). RESULTS: The mean 30-day mortality rate was 5.5 +/- 2%. The mean early mortality rate was 21 +/- 4% and 0% (p < 0.001), respectively, in patients with and without dissecting aortic aneurysms. There were two late deaths that were due to a pulmonary neoplasm and a cerebrovascular accident. The mean 16-year survival rate was 91.7 +/- 3.2%. The mean hazard of freedom from death was constant beyond 3 years (8.5 +/- 3.5%). No patient required reoperation. Furthermore, the long-term clinical follow-up was marked by a complete absence of endocarditis, anticoagulant-related hemorrhage, valve thrombosis, and prosthesis failure. Finally, patients showed a significant improvement in mean New York Heart Association functional status (1.3 +/- 0.1; p < 0.001 [postoperatively vs preoperatively]). CONCLUSIONS: In our experience, the late results of the Bentall operation were satisfactory. Our findings confirm that this technique still represents the procedure of choice for ARR with coronary reimplantation.

Actuarial Analysis↗
PubMed2003

Antibiotics to prevent complications following dental implant treatment.

BACKGROUND: Some dental implant failures may be due to bacterial contamination at implant insertion. Infections around biomaterials are difficult to treat and almost all infected implants have to be removed. In general, antibiotic prophylaxis in surgery is only indicated for patients at risk of infectious endocarditis, for patients with reduced host-response, when surgery is performed in infected sites, in cases of extensive and prolonged surgical interventions and when large foreign materials are implanted. To minimise infections after dental implant placement various prophylactic systemic antibiotic regimens have been suggested. More recent protocols recommended short term prophylaxis, if antibiotics have to be used. With the administration of antibiotics adverse events may occur, ranging from diarrhoea to life-threatening allergic reactions. Another major concern associated with the widespread use of antibiotics is the selection of antibiotic-resistant bacteria. The use of antibiotics in implant dentistry is controversial. It would be useful to know whether prophylactic antibiotics are effective in reducing failures of dental implants. OBJECTIVES: To assess the beneficial or harmful effects of the administration of prophylactic antibiotics for dental implant placement versus no antibiotic/placebo administration and if antibiotics are of benefit, to find which type, dosage and duration is the most effective. SEARCH STRATEGY: We searched the Cochrane Oral Health Group's Trials Register, the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE and EMBASE. We handsearched several dental journals. No language restrictions were applied. Personal contacts and manufacturers of dental implants were contacted to identify unpublished trials. Most recent search: March 2003. SELECTION CRITERIA: Randomised controlled clinical trials (RCTs) with a follow up of at least 3 months comparing the administration of various prophylactic antibiotics regimens and no antibiotics/placebo to patients undergoing dental implant placement. Outcome measures were prosthesis failures, implant failures, postoperative infections and adverse events (gastrointestinal, hypersensitivity). DATA COLLECTION AND ANALYSIS: Screening of eligible studies, assessment of the methodological quality of the trials and data extraction were to be conducted in duplicate and independently by two reviewers. Results were to be expressed as random effects models using weighted mean differences for continuous outcomes and relative risk for dichotomous outcomes with 95% confidence interval. Heterogeneity was to be investigated including both clinical and methodological factors. MAIN RESULTS: No RCTs were identified. REVIEWER'S CONCLUSIONS: There is not appropriate scientific evidence to recommend or discourage the use of prophylactic systemic antibiotics to prevent complications and failures of dental implants. Even though the present review did not assess the effectiveness of prophylactic antibiotics for patients at risk for endocarditis, it seems sensible to recommend the use of prophylactic antibiotics for patients at high and moderate risk for endocarditis, with immunodeficiencies, metabolic diseases, irradiated in the head and neck area and when an extensive or prolonged surgery is anticipated.

Antibiotic Prophylaxis↗
PubMed2004

Should the ascending aorta be replaced more frequently in patients with bicuspid aortic valve disease?

OBJECTIVE: The optimal diameter at which replacement of the ascending aorta should be performed in patients with bicuspid aortic valve disease is not known. METHODS: We reviewed all patients with bicuspid aortic valves undergoing aortic valve replacement at our institution from 1979 through 1993 (n = 201). Patients undergoing concomitant replacement of the ascending aorta were excluded. RESULTS: Follow-up was obtained on 98% of patients and was 10.3 +/- 3.8 (mean +/- SD) years. The average patient age was 56 +/- 15 years, and 76% were male. The ascending aorta was normal (<4.0 cm) in 115 (57%) patients, mildly dilated (4.0-4.4 cm) in 64 (32%) patients, and moderately dilated (4.5-4.9 cm) in 22 (11%) patients. All patients with bicuspid aortic valves with marked dilation (>5.0 cm) underwent replacement of the ascending aorta and were therefore excluded. Fifteen-year survival was 67%. During follow-up, 44 patients required reoperation, predominantly for aortic valve prosthesis failure. Twenty-two patients had long-term complications related to the ascending aorta: 18 required an operative procedure to replace the ascending aorta (for aortic aneurysm), 1 had aortic dissection, and 3 experienced sudden cardiac death. Fifteen-year freedom from ascending aorta-related complications was 86%, 81%, and 43% in patients with an aortic diameter of less than 4.0 cm, 4.0 to 4.4 cm, and 4.5 to 4.9 cm, respectively ( P < .001). CONCLUSIONS: Patients undergoing operations for bicuspid aortic valve disease should be considered for concomitant replacement of the ascending aorta if the diameter is 4.5 cm or greater.

Aged↗