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PubMed2004

The decision to have a prosthesis: A qualitative study of men with testicular cancer.

The aim of this paper is to understand why some men decide to have a testicular prosthesis while others reject the idea and to explore the extent to which the option of a testicular prosthesis is adequately presented. Forty-five men with testicular cancer were interviewed about all aspects of their illness. Some men decided against a prosthesis for a number of reasons; they thought that the loss of a testicle was not visibly obvious, did not affect self-image, was not a long-term threat to masculinity, and that living with one testicle was comfortable. Some did not want additional surgery and others were concerned about safety issues. The men who decided to have a prosthesis were concerned about self-image and a threat to masculinity. They had a desire to look 'normal' and a wish to keep the orchidectomy secret. Some men felt that the decision had been rushed. Others wished that they had had information about the possibility of implants before the orchidectomy or they considered the information presented inadequate. We conclude that it is important to counsel men with testicular cancer about the advantages and disadvantages of having a testicular prosthesis and to give them time to consider issues such as cosmetic appearance, self-image, comfort, possible short term complications and long-term safety.

Adult↗
PubMed1990

[Hip tumor prosthesis--indication in a trauma center and results].

This is a report about six cases of replacement of the proximal femur by a cementless special prosthesis in modular system done in the Unfallkrankenhaus Wien-Meidling. One of the patients suffered by a lymphoma, three others had fractures caused by bone metastasis. One was a pertrochanteric fracture complicated by osteoporosis, and finally one fracture of the femur preceded by an insufficient implantation of a semitotal hip replacement. The hipsocket was supplied four times by a cementfree Polyäthylensocket, in one case a CLW-ring was implanted. Investigation showed that after a little more than two months the stump of femur became porous and by an average of eleven months the prosthesis was covered by bone. The complications were in one case an incomplete fracture of the diaphysis and in another case a luxation for three times. There are several indications for a tumor prosthesis: 1. Primary and secondary malignant tumors. 2. Bone metastasis with or without fractures. 3. Comminuted fractures complicated by various factors, e.g. osteoporosis. 4. Loosening of prosthesis with poor bone conditions or failed implantation of a standard prosthesis. Although the successes seem to be quite promisingly, this method should be applied in a quite differentiated way, as any retreat is nearly impossible, once started.

Aged↗
PubMed2006

Cervical disc prosthesis replacement and interbody fusion: a comparative study.

The purpose of this paper is to compare the new functional intervertebral cervical disc prosthesis replacement and the classical interbody fusion operation, including the clinical effect and maintenance of the stability and segmental motion of cervical vertebrae. Twenty-four patients with single C5-6 intervertebral disk hernias were specifically selected and divided randomly into two groups: One group underwent artificial cervical disc replacement and the other group received interbody fusion. All patients were followed up and evaluated. The operation time for the single disc replacement was (130 +/- 50) minutes and interbody fusion was (105 +/- 53) minutes. Neurological or vascular complications were not observed during or after operation. There was no prosthesis subsidence or extrusion. The JOA score of the group with prosthesis replacement increased from an average of 8.6 to 15.8. The JOA score of the group with interbody fusion increased from an average of 9 to 16.2. The clinical effect and the ROM of the adjacent space of the two groups showed no statistical difference. The short follow-up time does not support the advantage of the cervical disc prosthesis. The clinical effect and the maintenance of the function of the motion of the intervertebral space are no better than the interbody fusion. At least 5 years of follow-up is needed to assess the long-term functionality of the prosthesis and the influence on adjacent levels.

Adult↗
PubMed2001

Studies on the feasibility of a subretinal visual prosthesis: data from Yucatan micropig and rabbit.

BACKGROUND: To estimate the feasibility of the subretinal concept of a visual prosthesis, animal models and prototypes, each representing a certain aspect of the final prosthesis, were utilised to test for requirements for such a medical device: (1) the ability to elicit--by electrical stimulation--event-related central activity in the central visual system, and (2) the long-term biocompatibility and biostability of the implant within the subretinal space. METHODS: (1) In rabbit and Yucatan minipig, cortical evoked potentials were recorded with chronically implanted epidural electrodes during stimulation with light flashes as well as during electrical stimulation in the subretinal space. Voltage pulses ranging from -3 V to +3 V were applied via an acutely implanted electrode array on a wired prototype. (2) For biocompatibility studies a silicon-based micro-photodiode array (MPDA) was used that closely resembled the design and composition of the final prosthesis. Fourteen months after implantation, angiography was performed and the histological findings of the retina in the immediate vicinity of the implant were evaluated. RESULTS: (1) In both rabbit and minipig, subretinal electrical stimulation resulted in evoked cortical potentials that were comparable to visual evoked potentials. The lowest threshold levels for the subretinal stimulation were 0.6 V for rabbits and 2 V for minipigs. (2) Long-term stability of an implanted MPDA and its biocompatibility were proven for a postoperative period of 14 months. CONCLUSIONS: Data from animal experiments with certain prototypes of the final prosthesis suggest the feasibility of the concept of a subretinal visual prosthesis: Both requirements were met: (1) the functioning of the subretinal stimulation and (2) the biocompatibility of the MPDA implant.

Animals↗
PubMed2006

Biomechanics of the C5-C6 spinal unit before and after placement of a disc prosthesis.

The study consists of a biomechanical comparison between the intact C5-C6 spinal segment and the same segment implanted with the Bryan artificial disc prosthesis (Medtronic Ltd., Memphis, TN, USA), by the use of the finite element (FE) method. Our target is the prediction of the influence of prosthesis placement on the resulting mechanics of the C5-C6 spine unit. A FE model of the intact C5-C6 segment was built, employing realistic models of the vertebrae, disc and ligaments. Simulations were conducted imposing a compression preload combined to a flexion/extension moment, a pure lateral bending moment and a pure torsion moment, and the calculated results were compared to data from literature. The model was then modified to include the Bryan cervical disc prosthesis, and the simulations were repeated. The location of the instantaneous center of rotation (ICR) of C5 with respect to C6 throughout flexion/extension was calculated in both models. In general, the moment-rotation curves obtained from the disc prosthesis-implanted model were comparable to the curves obtained from the intact model, except for a slightly greater stiffness induced by the artificial disc. The position of the calculated ICRs was rather stable throughout flexion-extension and was generally confined to a small area, qualitatively matching the corresponding physiological region, in both models. These results imply that the Bryan disc prosthesis allows to correctly reproduce a physiological flexion/extension at the implanted level. The results of this study have quantified aspects that may assist in optimizing cervical disc replacement primarily from a biomechanical point of view.

Arthroplasty, Replacement↗
PubMed1980

The role of echocardiography in the selection of mitral valve prosthesis.

Assessment of the left ventricular outflow tract was made echographically in 70 patients who subsequently received a mitral prosthesis. Group A (44 patients) had normal left ventricular outflow tract width (greater than 20 mm.); 13 received the Starr-Edwards prosthesis and nine received the Braunwald-Cutter prosthesis. There were two patients with low cardiac output syndrome and no hospital deaths. Group B (26 patients) had a narrow left ventricular outflow tract (less than 20 mm.). Thirteen patients received the Starr-Edwards prosthesis. One patient had low cardiac output syndrome, and there were no hospital deaths. We conclude that the use of the ball-and-cage prosthesis in the mitral position in patients with a narrowed left ventricular outflow tract (less than 20 mm.) measured echographically is not associated with an increased surgical risk.

Adult↗
PubMed1978

An evaluation of the wire mesh prosthesis in primary reconstruction of the mandible.

A stainless steel wire mesh prosthesis was used as a primary mandibular replacement in 102 patients after resection of malignant neoplasms arising in the head and neck. In sixty-seven patients the prosthesis was considered successful. Failure of the host to tolerate the prosthesis was associated with a history of previous irradiation, extensive resections, and loss of distant skin flaps used for coverage of the prosthesis. We conclude that the wire mesh mandibular prosthesis is an excellent means to accomplish prompt functional and cosmetic reconstruction after mandibular loss and does not preclude the use of a more complex modality of reconstruction if the initial implant is removed.

Humans↗
PubMed1981

A surgical interim prosthesis.

This technique for making a surgical interim obturator allows for immediate replacement of the anterior teeth and maxillary arch form, greatly alleviating the physiologic and psychologic shock of a maxillectomy to the patient (Fig. 5). The technique also reduces the number of visits normally required to provide separate surgical and interim obturators. The tongue and lips can maintain a near normal anatomic relationship with the teeth and palate facilitating the return of normal eating, swallowing, and speaking. The initial prosthesis can be used until the patient is ready for his definitive prosthesis. As tissues change, the prosthesis can be modified, eliminating the need for a separate interim prosthesis, which reduces treatment time and cost. A second interim prosthesis can be made, if necessary, but the esthetic requirements will be easily attained since the patient's natural dental and gingival shape, position, and contour have been preserved. The palatal portions made of clear acrylic resin, which allows the surgical margins and pressure areas to be observed.

Humans↗
PubMed2005

A self-contained, mechanomyography-driven externally powered prosthesis.

The measurement of the low-frequency (5-50 Hz) "sounds" or vibrations produced by contracting muscles is termed mechanomyography (MMG). As a control signal for powered prostheses, MMG offers several advantages over conventional myoelectric control, including, nonspecific sensor placement, distal signal measurement, robustness to changing skin impedance, and reduced sensor costs. The objectives of this study were to demonstrate 2-function prosthesis control based on a triplet of distally recorded, normalized root mean square MMG signals and to identify necessary future research toward full clinical implementation of MMG signals in upper-limb externally powered prostheses. A novel self-contained MMG-driven prosthesis for below-elbow amputees was designed, implemented, and preliminarily tested on 2 subjects. This prosthesis was composed of specialized software and hardware modules that emulate a 2-site electromyography sensing system. Although the use of MMG signals for prosthesis control has been shown previously, we report, for the first time, successful control within a self-contained unit in unconstrained environments. Specifically, essential requirements for practical use, such as standardized sensor attachment, basic noise elimination, and miniaturization of the system, have been achieved. Both subjects were able to voluntarily open and close the prosthesis hand with no significant delays from intention to action (approximately 120 ms). Quantitative analyses revealed 88% and 71% control accuracy for subjects 1 and 2, respectively.

Adult↗
PubMed2005

Functional improvement with digital prosthesis use after multiple digit amputations.

PURPOSE: Patients who sustain traumatic amputation of multiple fingers suffer both a functional and psychologic loss. Previous studies of prosthesis use for finger amputees have focused primarily on the psychologic benefits. Clinically our group noticed a functional improvement on hand function tests when patients with multiple digit amputations used a prosthesis. Given the expense of multiple finger prostheses we sought to determine if they led to a consistent functional improvement in these patients. METHODS: Ten consecutive patients performed a battery of hand function tests and rated their ability to perform a variety of activities of daily living both with and without their prosthesis using the Disabilities of the Arm, Shoulder, and Hand questionnaire. RESULTS: Our results show a significant improvement in 3-finger-pinch strength and grip strength and a trend of improvement of tip-pinch, lateral-pinch, and grip strength in dynamometer positions 1, 2, 3, and 4 in these patients when tested with and without their prostheses. Function in activities of daily living, as assessed by the Disabilities of the Arm, Shoulder, and Hand questionnaire, was improved globally with prosthesis use. In addition, significant improvement was noted in several specific activities including opening a jar, writing, and turning a key, among others. CONCLUSIONS: These results show that prosthesis use provides a functional benefit to these patients in multiple activities.

Activities of Daily Living↗
PubMed2002

[Laparoscopic treatment of large hiatal hernias using a prosthesis. Report of ten cases].

OBJECTIVE: To evaluate prospectively the laparoscopic surgery for giant hiatal hernias treated by fundoplication and hiatal prosthesis. PATIENTS AND METHODS: Ten patients were included in this study. Surgical technic included the dissection of oesophageal hiatus, the sac excision and the dissection of the abdominal oesophagus to obtain a physiological length. The decision criterion for a prosthesis was the hiatus oesophagus diameter of 5 cm or more. The crura were closed and the hiatus was reinforce by a prosthesis of 15 x 15 cm. All patients underwent a fundoplication whether partial or complete. RESULTS: Eight patients had a type III hernia, and 2 had a type II. The mean size for the hiatus was 6.5 cm (5.5-8). Eight patients underwent a total fundoplicature and 2 a partial one. The prosthesis was made of polypropylene in 5 cases. Average operating time was 182 min (78-240). One patient had postoperative morbidity, with gastroplagia which resolved. There was no mortality. Mean hospitalisation duration was 7.7 days (5-12). No one case of recurrence have been noticed after a mean follow-up of 24 months (8-40). CONCLUSION: It appears that the large size hiatal hernia (more than 5 cm) can be treated with good results by using a prosthesis during laparoscopic fundoplication.

Aged↗
PubMed2005

[Ossiculoplasty with KURZ titanium prosthesis].

OBJECTIVES: Report the functional and anatomic results of ossicular reconstruction by titanium prosthesis. MATERIALS AND METHODS: Retrospective chart reviews were performed for 111 patients who had undergone titanium ossicular implants between November 1998 and 2002 (61 PORP, 50 TORP). The anatomical and audiometric data were analyzed on average at 3 and 20 months. RESULTS: At 20 months, the improvement of air-bone-gap mean was 12.7 dB with better results at low frequencies. The global success rate was 66% (PORP 77%, TORP 52%). It decreased significantly in the open techniques. Extrusion rate was low (2/111) and the labyrinthization rate was 3.6%. Twenty patients required a surgical revision (18%). In 9 patients, the prosthesis was too short. At long-term follow-up, the gains were stable in 60 patients, improved in 32 patients and worsened in 19 patients. CONCLUSION: The success rate is higher in the group of the PORP with the closed technique. The stability of the TORP in open technique still remains problematic. In all cases, the risk of extrusion requires a large cartilage graft recovering the plate of the prosthesis. The high rate of luxation (9/111 prosthesis too short) has led us to increase slightly the length of the prosthesis (+1.22 mm mean).

Adolescent↗
PubMed2000

Analysis of a femoral hip prosthesis designed to reduce stress shielding.

The natural stress distribution in the femur is significantly altered after total hip arthroplasty (THA). When an implant is introduced, it will carry a portion of the load, causing a reduction of stress in some regions of the remaining bone. This phenomenon is commonly known as stress shielding. In response to the changed mechanical environment the shielded bone will remodel according to Wolff's law, resulting in a loss of bone mass through the biological process called resorption. Resorption can, in turn, cause or contribute to loosening of the prosthesis. The problem is particularly common among younger THA recipients. This study explores the hypothesis that through redesign, a total hip prosthesis can be developed to substantially reduce stress shielding. First, we describe the development of a new femoral hip prosthesis designed to alleviate this problem through a new geometry and system of proximal fixation. A numerical comparison with a conventional intramedullary prosthesis as well as another proximally fixed prosthesis, recently developed by Munting and Verhelpen (1995. Journal of Biomechanics 28(8), 949-961) is presented. The results show that the new design produces a more physiological stress state in the proximal femur.

Adult↗
PubMed1978

Obturator prosthesis design for acquired maxillary defects.

Fabrication of obturator prostheses does not require a special ability to fabricate a prosthesis extension into a defect or an arbitrary extension of a prosthesis into a defect. Fabrication of an obturator prosthesis depends on the application of basic prosthodontic principles that are used in the treatment of patients without maxillary defects. Some principles must be modified because of the defect and the character and position of the remaining structures. The defect, in conjunction with the remaining structures, must be used to provide support, retention, and stability of an obturator prosthesis. If basic prosthodontic principles are applied the size and extension of the obturator will be determined, and the extensive variation so commonly seen in obturators will be minimized. Acceptable prosthodontic care for the patient with the acquired maxillary defect should include cautious prosthesis design combined with routine maintenance care to provide comfort, function, cosmetics, and minimal change to the compromised remaining structures.

Alveolar Process↗
PubMed1992

Management of preexisting inflatable penile prosthesis during radical retropubic prostatectomy.

A potentially difficult technical situation exists when a man with a functioning inflatable penile prosthesis elects radical prostatectomy as treatment for localized prostate cancer. Between February 1988 and June 1991 we encountered 8 men with a preexisting inflatable penile prosthesis who subsequently underwent radical retropubic prostatectomy. In 2 patients the reservoir portion of the prosthesis was in the perivesical space such that radical prostatectomy could be performed without difficulty. However, in 6 patients removal of the reservoir was necessary to complete the prostatectomy. In 3 of these 6 patients the reservoir was replaced at 3 to 6 months after radical prostatectomy and all 3 systems function well. The remaining 3 patients have not yet elected replacement of the reservoir. Only 1 patient had an infection and a complication attributable to the prosthesis. We believe that a preexisting inflatable penile prosthesis should not preclude successful radical retropubic prostatectomy, although temporary removal of the reservoir may be required.

Aged↗
PubMed1988

Evaluation of patients and partners 1 to 4 years after penile prosthesis surgery.

One to 4 years after penile prosthesis implantation 52 men and 22 partners were interviewed personally. All except 4 patients were having intercourse on a regular basis. A quarter of the patients reported restriction in intercourse positions, possibly because of a smaller penis postoperatively, and 15 per cent reported decreased orgasm intensity. Six men had an undiagnosed prosthesis malfunction or they used an inadequate pumping technique, suggesting that prosthesis patients should be followed on a continuing basis. The 52 men had experienced 10 malfunctions with the prosthesis. Partial erections were reported by 69 per cent of the patients but this could be confirmed in only 1 of 10 with visual sexual stimulation testing. It is suggested that differences between prosthesis models are more a result of psychological, relationship and health factors than mechanical factors. Of the patients 79 per cent would undergo the operation again but only 59 per cent of the partners had no hesitations. The longer the postoperative period the more hesitations. A satisfaction score was used to measure patient satisfaction.

Coitus↗
PubMed1985

Early problems encountered with the Mentor inflatable penile prosthesis.

We present 9 consecutive patients who underwent insertion of the Mentor inflatable penile prosthesis. Of these patients 3 had successful results after repeated problems with the Scott inflatable penile prosthesis. Complications included spontaneous inflation of the prosthesis, a tubing kink, aneurysmal cylinder ballooning and cylinder disruption. Slow deflation seems to be an inherent problem with the Mentor system. Although penile squeezing may be used to help deflation, traumatic urethritis may occur. However, concealment may not be possible without such squeezing. Interim use of a noninflatable prosthesis to treat a damaged corpus cavernosum is recommended. Although ingenious technology has enabled successful implant surgery, no penile prosthesis yet devised has proven to be ideal. Further refinements are being made. Ultimate evaluation will require years of followup in the spirit of the pre-700 series of Scott inflatable penile prostheses.

Aged↗
PubMed1998

Prosthesis size in stapedectomy.

Primary stapedectomies were performed on 60 patients with bilateral otosclerosis. Every patient had a 4 mm long Robinson prosthesis with a 0.4 mm wide shaft placed in one ear and a 4 mm long Robinson prosthesis with 0.6 mm wide shaft placed in the opposite ear. With the 0.4 mm wide prosthesis, 54 patients overclosed the air bone gap and 6 were within 10 dB of closing. With the 0.6 mm wide prosthesis, which was placed in the opposite ear, 51 patients overclosed their air-bone gap and 8 were within 10 dB of closing. We conclude that there is no statistical difference in hearing results between the 0.4 mm and the 0.6 mm wide Robinson prosthesis when they are used in a partial stapedectomy with a vein graft covering the oval window.

Adolescent↗