Proplast implants used in otology and in facial reconstructive surgery

Proplast, a self-stabilising alloplastic material, was evaluated in ear surgery and in facial reconstructive surgery. Proplast implants were used on 33 patients to reconstruct the ossicular chain (total or partial ossicular replacement prosthesis), or to rebuild the mastoid cavity. The lack of extrusion over a 24-month period is encouraging. In facial reconstructive surgery 11 patients received Proplast implants to augment and restore facial contours. Contamination with saliva remains a problem, owing to the high porosity of Proplast, which could harbour infection. When Proplast was sterile when implanted, no extrusion appeared over a 12-month period. Although the patients presented here were followed up for a relatively short time, they provide reason for some optimism that the vexed question of alloplastics applied in the field of ear, nose and throat surgery may be solved.     

Implantation of electromagnetic ossicular replacement device

Semi-implantable hearing aids consisting of permanent middle ear implanted magnet, either partial ossicular replacement prostheses (PORP's) or total ossicular replacement prostheses (TORP's) driven by an electromagnet placed in the ear canal have been tested on six patients undergoing surgery for chronic otitis. The surgical and audiological problems are described. The audiological results were excellent in all six cases. A functional gain of 40-70 dB can be obtained for entire frequency range of the audiogram.     

Tragus perichondrium-cartilage island transplant in middle ear surgery. Method and results after 5 years

Temporalis fascia remains the most widespread material for reconstructing the tympanic membrane in tympanomastoid surgery. If total or partial ossicular replacement prostheses are needed or pathology of the eustachian tube causes ventilation impairment, a more rigid transplant material is required. Between 1989 and 1994 perichondrium-cartilage composite grafts were used in a series of 597 cases of tympanomastoid surgery performed at the University ENT Clinic of Würzburg. The graft was taken from the tragus and prepared as a cartilage island with perichondrium attached to one side, the perichondrium-cartilage island transplant (PCI). If reconstruction of the ossicular chain was necessary, glass ionomer cement protheses (IONOS) were used. Closure of the tympanic membrane could be achieved in 90% of all cases. In those cases where ossicular chain reconstruction was postponed to a second procedure, closure of the drum was achieved in 96%. The audiological results of the different type III procedures were evaluated. By using the PCI technique a favorable closure of the air-bone gap to 10-25 dB was achieved, even in cases with advanced ear pathology technique and results are presented in detail.     

Bladder cancer in a patient on long-term haemodialysis

OBJECTIVE: The results of the first cohort of 60 cavity reconstructions with hydroxyapatite with a minimum follow-up period of 15 years were studied. STUDY DESIGN: The study design was a retrospective study. PATIENTS: A total of 60 patients had a follow-up period of >15 years. In four patients, not all data were available. Therefore, 56 patients were included in the study. They had a combination of cavity problems and hearing loss. INTERVENTION: The ear canal was reconstructed with a canal wall prosthesis of porous hydroxyapatite. The ossicular chain was reconstructed with an incus or incus-stapes prosthesis of dense hydroxyapatite. RESULTS: After 15 years, 42 patients (75%) had an intact reconstructed ear canal. The main problem for failure was the recurrent purulent middle ear infection and not cholesteatoma. The histology of the retrieved canal wall showed a good remodeling in living bone tissue. After 15 years, 34 patients had a normal ear canal and an ossicular chain. Of these patients, 7.05% had an air-bone gap closure within 20 dB. CONCLUSIONS: Long-term results of cavity reconstruction with hydroxyapatite are possible. The main problem is recurrent mucosal disease of the new middle ear-mastoid cleft.     

Prosthetic replacement of the ureters

STUDY AIM: The aim of this study is to demonstrate the reliability of silicone prosthesis for the replacement of ureters. This prosthesis derives from the biliary prosthesis developed after a personal experimental study continued by Triboulet. PATIENTS AND METHODS: In 38 patients suffering from a malignant disease, a right silicone prosthesis was used for the replacement of an ureter during a 20-year period. There were 30 female and eight male patients. The mean age was 71 (range: 51-88 years). Forty one prostheses were used; one patient underwent two successive operations on the same side with a change of prosthesis, and two patients required a bilateral prosthesis. There were 12 gynaecological carcinomas (three with ureteral fistula), three prostatic carcinomas, 16 cancers of the rectum and recto-sigmoid junction, four cancers of the right colon with retroperitoneal carcinomatosis, and three ureteral fistulas after extended colonic resection. RESULTS: Early complications were limited to ureteral fistulas (n = 6, 16%) in patients who had already a preoperative fistula (n = 3) and in patients with peritoneal metastases on the superior wall of the bladder. The secondary destruction of the kidney (four secondary nephrectomies) occurred when the function of the kidney was already impaired at the time of the procedure. There were no secondary fistulas, no secondary obstruction of the prosthesis. The longest follow-up was 69 months. CONCLUSION: The silicone prostheses used for the replacement of ureters are reliable and still permeable beyond 5 years. The protection of the renal function in patients often submitted to chemotherapy improves the duration and quality of survival. These prostheses must be reserved to advanced malignant diseases with a rather long life expectancy.     

Titanium as a biomaterial for ossicular replacement: results after implantation in the middle ear of the rabbit

The middle ear poses unique challenges when finding suitable materials for ossicular reconstruction, primarily because of its link to the external environment via the eustachian tube and, hence, its greater exposure to infectious agents. In this study, the biocompatability of titanium was examined in the middle ear of rabbits by using light and scanning electron microscopy. Implants were placed as middle ear prostheses or as free implants. These were inspected at 28 days, 84 days, 168 days, 336 days and 504 days following implantation for mucosal coverage, percent epithelization and any sign of foreign-body reaction. After 28 days, the prostheses were covered by regular mucosa. Although a majority of the free implants took up to 336 days for complete epithelialization, some of the free implants were not epithelialized even at day 504. There were no inflammatory cells observed on the surface of the material, nor were unusual amounts of fibrous tissue seen. In addition, the titanium material exhibited an affinity toward bone. The results of this animal experiment indicate that titanium is a favorable material for ossicular replacement prostheses.     

Immunodiffusion and immunohistochemical investigations on the reactivity of oxide ceramic middle-ear implants

Oxide ceramic materials (partial and total ossicular replacement prostheses) have been implants of preference for the reconstruction of the ossicular chain because of their excellent biocompatibility. The reaction on the surface of the implants takes place at three biodynamic levels according to the model of Stern's bilayer. We investigated the adsorption of proteins, which is determined by the cellular reaction and degradation to the surface using radial immunodiffusion and immunohistochemical methods. First, ceramic implants of aluminum oxide, hydroxyapatite, glass ceramic and zirconium oxide have individual actual (i.e. biological) surfaces. With a perthometer and the contact-free laser Focodyn method we determined each actual (i.e. biological) surface of the various ceramic implants mentioned above. Using radial immunodiffusion, the adsorption of albumin, glycoprotein, plasminogen, fibronectin, IgA, IgG and IgM shows characteristic rates of adsorption to the respective ceramic surfaces in correlating to the actual surface. A cross-check with fluorescent antibodies confirmed the protein adsorption. The individual surface adsorption of the proteins remains characteristic and is the basis for the recording of cellular reactions after implantation.     

Successful chemotherapy in a patient with recurrent carcinoma of the urachus

OBJECTIVE: Titanium in other parts of the body, well known for its biocompatibility, was examined in an animal model for its use as an ossicular replacement material. STUDY DESIGN: The biocompatibility of titanium was studied in the middle ear of rabbits using light and scanning electron microscopy. Titanium pins were placed as middle ear prostheses or as free implants and were examined after 28, 84, 168, and 336 days. RESULTS: After 28 days, the prostheses were covered by regular mucosa. The free implants took up to 336 days to be totally epithelialized. There were no inflammatory cells observed on the surface of the material nor were unusual amounts of fibrous tissue seen. In addition, the titanium material exhibited an affinity toward bone. CONCLUSIONS: The results of this animal experiment indicate that titanium is a useful material for ossicular replacement prostheses.     

Tissue reactions to glass ceramics in the middle ear

The bioactive glass ceramic "Ceravital" was used to fashion prostheses for the replacement of various ossicles in the middle ear. They were tested in 70 rabbit ears, where they were accepted in osseous areas without formation of surrounding fibrous tissue. Histological examinations regularly showed an osseous bond with the surrounding bony tissue. Mucous membrane covered these ossicular chain prostheses and showed no evidence of inflammatory reactions. Glass ceramic implants were also used to reconstruct the ossicular chain and the posterior wall of the outer ear canal in 100 patients. The functional results were satisfactory in all cases.     

Reconstruction of the stapes superstructure with bioactive ceramics

In this study we examined the feasibility of rebuilding a stable stapes superstructure for a new articulated ossicular chain by using bioactive ceramics. Dense hydroxylapatite and ceravital were tested in guinea pigs. The ceramic prosthesis was placed on the remnants of the footplate to create a bony connection without touching the tympanic membrane, thereby protecting it from relative movements. The implants were explanted together with the stapes footplate at six weeks and three months, respectively. Histologically, bony connections were found between all ceramic implants and the remnants of the crura even at six weeks and became more pronounced after three months.     

Thrombosis: relation to fibrinolysis]

Prosthetic voice restoration has considerably improved the results of vocal rehabilitation after total laryngectomy, and is presently the method of choice for many health-care providers treating laryngectomized patients. The Provox voice prosthesis, developed in the Netherlands Cancer Institute, is an indwelling device that has been applied in recent years with regular success. Its retrograde replacement method, using a disposable guide wire, assures reliable, atraumatic positioning of the prosthesis in the tracheoesophageal fistula. However, the method sometimes may be uncomfortable for the patient; therefore an adapted prosthesis and new replacement equipment were developed, which enable bidirectional insertion, i.e. not only in the traditional retrograde manner through the pharynx, but especially in an anterograde manner through the stoma. This second-generation voice prosthesis (Provox 2) was studied in a prospective clinical trial in 44 patients (33 experienced patients, seven first-time replacements and four primary insertions). The study demonstrated that the anterograde insertion with the Provox 2 system was applicable in all patients, making the voice prosthesis even easier to handle than with the traditional retrograde method. A stenosis of the pharyngoesophageal segment no longer interfered with the replacement. In addition, the patients judged the new method as being favourable, reporting significantly less discomfort during the replacement procedure (paired Student's t-test: p < 0.0001). Furthermore, the adapted voice prosthesis could be removed from the tracheoesophageal fistula without excessive force (mean 7.9 N, range 6.0-14.0 N), more easily than the original Provox (mean 20.9 N, range 5.5-25.0 N). It can be concluded that this second-generation indwelling voice prosthesis (Provox 2) seems to be a further improvement in the application of this voice rehabilitation system, not only simplifying the replacement procedure, but also diminishing the discomfort for the patient.     

Results of knee replacement with the Walldius and geometric prostheses. A comparative study

Sixty-two knees that were replaced with Walldius prostheses and twenty-five knees with geometric replacements were studied prospectively. The follow-up ranged from twenty-four to 162 months (average, seventy-four months) for the knees with the Walldius prostheses and from twenty-four to seventy-five months (average, forty-seven months) for those with the geometric prostheses. Using a 100-point clinical rating scale, the knees of patients who underwent Walldius replacement improved from their preoperative status by an average of 33 points (from 44 to 77 points) and those with geometric prostheses, an average of 24 points (from 54 to 78 points). Twelve patients with twenty Walldius prostheses were followed for more than 100 months (average, 127 months). The greater average improvement (36 points) in this group was due primarily to the absence of any major complications. Six patients underwent replacement of one knee with a Walldius prosthesis and one knee with a geometric implant. Although the ratings for the two knees were similar in each patient, four patients preferred the Walldius implant; one, the geometric replacement; and one had no preference. Significant technical errors or complications (defined as those affecting the end result) occurred in 8 per cent of the knees with Walldius implants and in 12 per cent of the knees in the geometric group. There were two late infections in each group. One Walldius prosthesis was removed and the knee was fused. The other three prostheses (one Walldius and two geometric) associated with infection were salvaged.     

Influence of local air suction on the density of air-borne bacteria during cementation of alloplasties

At joint replacement operations local air suction is used to reduce the air pollution from organic solvents in the operation theatre during insertion of cement and prosthesis. In order to find out whether the local suction in an ultraclean-air operation theatre with laminar airflow influenced the number of colony forming units (cfu) of bacterial in vicinity of the wound, one m3 of air was sampled 20 cm and one metre from the wound before, during and after use of local suction during insertion of cement and prosthesis using a Sartorius membrane filter sampler. There was no significant difference between the groups in the numbers of cfu of bacteria found. It is concluded that use of local air suction over the operative area while cementing hip prosthesis does not affect the number of bacteria in the vicinity of the operation.     

Results of disc prosthesis after a minimum follow-up period of 2 years

STUDY DESIGN: This study analyzed retrospectively 46 patients undergoing artificial disc replacement. OBJECTIVE: To assess the clinical and radiographic outcomes of patients who had Charitè SB III disc prosthesis. SUMMARY OF BACKGROUND DATA: Results of disc prosthesis have been reported only at very short-term follow-up periods; preoperative diagnosis and criteria used to evaluate the clinical outcomes were not reported. METHODS: Forty-six patients who had had a disc prosthesis were evaluated clinically and radiographically at least 2 years after surgery. Preoperative diagnosis included disc degeneration in 22 patients and failed disc excision in 24 patients. Disc prosthesis was implanted at a single vertebral level in 36 patients and at two levels in 10 patients. Follow-up evaluation was performed after an average of 3.2 years (range, 2-5 years). RESULTS: Sixty-three percent of patients reported satisfactory results. The success rate was 69% in patients who underwent isolated disc replacement and 77% in those with no previous back surgeries. Seven patients who had unsatisfactory results underwent posterolateral fusion without removing the artificial disc. Two patients underwent removal of the prosthesis. No failure of the implants or loosenings or wear of the polyethylene core were found. Vertebral motion averaged 9 degrees at the operated levels and 16 degrees at the adjacent levels. CONCLUSION: A wrong surgical indication, rather than failure of the prosthesis, appears to be the main cause of unsatisfactory results of disc replacement at medium-term evaluations. Prospective and longer term studies are needed to establish whether disc prosthesis may offer advantages compared with spinal fusion.     

Ossicular coupling of an implantable hearing aid transducer using an Er:YAG laser

Special coupling devices made of pure gold or titanium have been developed to connect a new implantable hearing aid transducer (Tübingen implant) to the ossicular chain. They allow piezotransducer probe-tip connection to the long process of the incus or the stapedial head. Similar to the design of conventional PORPs (partial ossicular replacement prostheses), the coupling devices can be fixed at the ossicular chain, e.g., with the eye loop of stapedial piston prostheses or the bell element of golden wire PORPs. A crimp technique allows connection between coupling device and transducer probe tip [5]. The main disadvantage in connecting the long process of the incus or the stapes having is to drill a dorsal tympanotomy in the posterior wall of the ear canal during surgery. The short distance between tympanotomy and N. facialis contains serious surgical risks. To avoid the risk of facial paralysis, Fredrickson's alternative coupling technique for the body of the incus is investigated in this paper [2]. In this case, the transducer probe tip will be positioned to the incus body and placed on its surface with controlled elastic displacement of the ossicular chain. The simple direct attachment of the probe-tip end on the surface of the incus, however, will not guarantee a stable long-term connection. Thus, by creating a conical, 0.5-to 0.7-mm-deep hole in the incus, the probe tip will be fitted much better. With a novel surgical Erbium-YAG laser this can be done in a contactless procedure. In this paper, first results of microsurgical laser applications with human temporal bones will be shown.     

Skin flaps and expanded full-thickness skin grafts. Indications in the repair of burn sequelae

The great majority of sequelae of deep burns concern the skin. Their correction essentially raises problems of replacement of scarred skin by good quality skin. Sequelae of burns logically constitute one of the best indications for progressive mechanical skin expansion by prosthesis, which allows for considerable improvement of the aesthetic results. This improvement is related to the use of skin replacement tissues with the same quality as the original tissue. Local expanded flaps and expanded full-thickness skin grafts are the two essential techniques used. The authors review the general rules concerning the use of expansion prostheses, then describe the various indications for expanded flaps and expanded full-thickness skin grafts in the sequelae of burns of the face, neck, thorax and limbs. The main indications are illustrated by clinical cases.     

Studies on the surface and new joint capsule of McKee-Farrar prosthesis implanted for several years (author''s transl)

These studies are intended as a critical contribution to the question, wether the McKee-Farrar (MF) prosthesis, on account of its stronger friction and the consequences of this, as compared to other models, still has its justification or wether these "secundary" manifestations indicate that this prosthesis should be abandoned. Studies on primary and secundary alteration of the surface were carried out on exchanged MF prosthesis with the aid of the grid electron microscope. The signs of wear are clearly visible and can be differenciated from production artefacts. The movement and deposit of abraded particles into the new joint capsule was studied qualitatively and quantitatively with the aid of radioisotopes. All samples showed an increased accumulation of chrome in the tissues as compared to cobalt. There is no indication of significant damage. On the basis of the results of these studies and on account of the favourable personal experience from a surgical and clinical point of view -- particulary with reference to minimal preparation of the acetabulum and ready replacement, the MF prosthesis will continue to hold its place as the standard model for total prosthetic hip joint replacement.     

Systemic hypertension as a risk factor for complications with an aortic mechanical valve

We sought to determine the effect of preoperative systemic hypertension on prosthesis related complications or postoperative aortic dissection after valve replacement in patients with aortic regurgitation. The patients were divided into two groups according to the presence or absence of systemic hypertension: Group I, with hypertension (n = 35), and Group II, without hypertension (n = 37). The survival rate and event free rate were examined for 72 patients who were alive 30 days after valve replacement with a St. Jude Medical valve for aortic regurgitation. The cumulative 10 year survival rate of Group I (65% +/- 12%) was lower than that of Group II (79% +/- 15%). The 10 year event free rate of all prosthesis related complications was 62% +/- 13% in Group I, and 96% +/- 3% in Group II (p < 0.05). The 10 year event free rate for ascending aortic dissection was 73% +/- 12% in Group I and 100% in Group II (p < 0.05). The linearized event rate of all prosthesis related complication was 3.8% per patient-year in Group I and 0.5% per patient-year in Group II. In conclusion, systemic hypertension was a risk factor for prosthesis related complications and for complicated aortic lesions after aortic valve replacement. Careful postoperative management for hypertension is necessary in patients with systemic hypertension after aortic valve replacement. Tissue valves may be recommended in patients with aortic valve disease and severe hypertension.     

Gnathosonic study of occlusion in patients wearing complete dentures

The results of the placement of endoscopic endoprosthesis in 51 patients with choledocholithiasis from October 1991 to December 1995 are reviewed. In 13 cases the endoprosthesis was provisionally placed. Surgical or endoscopic treatment was electively completed in all the cases. Thirty-eight patients received the endoprosthesis on a permanent basis. During the follow up (mean 15.2 months) extraction was completed and the prosthesis removed in three cases, one by emigration. Six patients presented recurrent biliary obstruction and underwent surgery or replacement of another prosthesis. In the latter cases, another two underwent surgery due to repeated obstructions. The remaining patients remained asymptomatic until the end of follow up or until death (8 cases) due to unrelated causes. Only three mild episodes of cholangitis were observed as complications related to prosthesis placement. The authors conclude that endoscopic endoprosthesis is an effective provisional treatment to solve acute situations and is a permanent alternative for unextracted choledocholithiasis following sphincterotomy in patients who cannot undergo other techniques and who have a short life expectancy.     

The effect of hydroxyapatite coating on the fixation of hip prostheses. A comparison of clinical and radiographic results of hip replacement in a matched-pair study

The efficacy of a total hip replacement with a hydroxyapatite-coated hip prosthesis was compared with that of an uncoated, cementless prosthesis of the same type. Preoperatively, there was no difference in the patient's diagnosis, hip score, age, and sex. All operations were performed by one surgeon in a standardized manner. The choice of the implant was randomized, and the follow-up period was equal for both types. The implant used was associated with a poor outcome due to a high incidence of early aseptic loosening. Probably because of a poor initial fixation, there was a significant difference in the clinical results after a short follow-up period when an additional HA layer was used. According to the patients' pain, migration of the implant, and presence of a progressive radiolucent line, use of the HA-coated prosthesis led to a significantly better result; however, we also found an increased rate of heterotopic bone formation in the HA-coated group. It was concluded that the HA coating improves the initial fixation of a hip prosthesis.