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A case of esophageal cancer infiltrating the left bronchus pars membranacea and the aneurysmal aortic wall was resected en bloc with the bronchial and aortic wall. Descending aorta was substituted by means of a Dacron prosthesis fitted with expandable devices at both ends, allowing a very significant reduction of the clamping time and simplification of this part of the procedure.
A 14-year-old girl with a congenitally deformed and shortened right leg and foot is described. The patient could not bear weight on the deformed limb and had to hop on the left leg. The deformed foot faced backwards and had nine toes. The right leg was shorter than the left by 26 centimetres. Radiologically, the lower end of the right femur was ill-developed and there was no knee joint. There were two fibulae and the tibia and the patella were absent. A through-knee disarticulation was done and a prosthesis fitted later. The amputated leg and foot were dissected. Many of the muscles in the leg and foot were duplicated. There were two calcanei, one talus, one navicular, two cuboids and four cuneiforms. Ther were nine metatarsals, and all the toes had three phalanges except for one which had two.
Very often clinicians prescribe a limited number or only one type of knee mechanism because it has been found reliable or perhaps specific information on the range and variety of all available mechanisms has not been on hand. The clinician rarely has the opportunity to see all the mechanisms in a common perspective to compare the relative merits of one mechanisms with another. An attempt has been made to enumerate the available human knee-prostheses, both implants and external prostheses, according to their motion. An historical development of knee prosthesis is discussed. A classification procedure is developed for both internal and external prostheses based on their primary functions. The two major classifications in either of these prostheses are monocentric and polycentric mechanisms. A mechanism whose center of rotation does not change through out the range of motion is considered as monocentric mechanism and a mechanism whose center of rotation changes during its operation is considered as polycentric mechanism. The implants are categorized as hinged and non-hinged knee joints. The external prostheses are further classified based on certain primary functions like control in swing phase and/or in stance phase and in extension. The hierarchical classification scheme will benefit kinematicians and designers to analyze the available mechanisms and make necessary improvements. This will also provide a ready-reference to the prosthetists in selecting the best-fit prosthesis from a large family of prostheses.
In the last few years hip arthroplasty has been increasingly used and both metaphysis and diaphysis of the proximal femur are studied preoperatively for best compliance between prosthesis and bone. Indeed, the best results can be obtained by reducing the risk of stem end mobilization, which means to choose the prosthesis fitting the femoral canal best and to limit the use of cement prostheses, which are at high risk of mobilization in time, to advanced osteoporosis patients. We used a simple and repeatable CT technique to study femoral canal structure and size. After accurately positioning the patients inside the gantry, we acquired some axial scans at scheduled levels referring to the horizontal midline of the lesser trochanter. The axial scans were acquired 2 cm above and 5 and 10 cm below the horizontal midline in 105 patients. Measurements were bilateral in 13 patients. Finally, the results were compared with the surgical outcome. Femoral canal cross-diameters and cortical bone width varied greatly, which variations were confirmed in bilateral measurements and in the same patient between the two femurs. Femoral canal structure, which can be remodelled, influences the choice of the stem and thus the amount of cement. We believe this method to be fundamental for correct surgical planning and for best treatment outcome.
The Hofer-Imhof cup consists of a parabola-shaped titanium acetabular component with flat threads. These flat threads are designed to be self-cutting and allow accurate insertion without incarceration, even in sclerotic bone. In a prospective study conducted from May 1988 to July 1989, 143 Hofer-Imhof cups were implanted. Radiographic assessment included initial bone contact, cup position, fixation on osteophytes, presence of any radiolucencies or sclerosis, cup migration and bone ingrowth. Initial prosthesis fit was evaluated with a 20 degrees caudally angled anteroposterior X-ray for accurate demonstration of the threads. 119 of the Hofer-Imhof cups (83.2%) were available for radiographic follow-up at a mean of 65 months (min. 37 mo., max. 95 mo.). One cup required revision after 23 months due to infection. The cups had an average inclination of 47 degrees, and complete bone contact was evident in 86.6% on the postoperative X-ray. In 8.4% of the cups, some threads were not in contact with bone at the edge of the acetabulum. At final follow-up, 82.4% had complete bone ingrowth without any evidence of radiolucency (type I), 15.1% had near-complete bone ingrowth with minimal radiolucencies (type II), and 2.5% had predominantly fibrous fixation (type III). One cup (0.8%) showed excessive migration. The technique of anchorage using a flat thread, minimal bone resection as a result of the parabolic shape and the sandblasted titanium surface are the characteristic features of the Hofer-Imhof threaded cup and produce good medium-term results in primary hip arthroplasty.
Bio-engineered cartilage has made substantial progress over the last years. Preciously few cases, however, are known where patients were actually able to benefit from these developments. In orthopaedic surgery, there are two major obstacles between in-vitro cartilage engineering and its clinical application: successful integration of an autologuous graft into a joint and the high cost of individually manufactured implants. Computer Assisted Surgery techniques can potentially address both issues at once by simplifying the therapy, allowing pre-fabrication of bone grafts according to a shape model, individual operation planning based on CT images and providing optimal accuracy during the intervention. A pilot study was conducted for the ankle joint, comprising a simplified rotational symmetric bone surface model, a dedicated planning software and a complete cycle of treatment on one cadaveric human foot. The outcome was analysed using CT and MRI images; the post-operative CT was further segmented and registered with the implant shape to prove the feasibility of computer assisted arthroplasty using bio-engineered autografts.
Traumatic loss of bone substance or post - decompression defects require the reconstruction of the skull. In cases of simple geometry there are handy, secure and cost effective procedures such as using autologuous cryopreserved bone flaps or polymerized Methylmethacrylat. For large sized defects CAD - taylored implants developed to provide a comfortable procedure to ensure high biocompatibility and perfect anatomical results by one - stage surgery. Furthermore cranioplasty does not only imply anatomical reconstruction but also functional recovery of awareness, cognition and motoric functions as shown in several studies according to changes in cerebral hemodynamics and metabolism. In our series of 286 patients who underwent cranioplasty during the past 10 years (1993-2003) we used taylored implants in 15 cases starting in 1999. All the patients included showed large sized defects > 64 cm2, complications did not occur neither during surgery nor the postoperative course, cosmetical results were excellent in all the patients. Neurological findings and the functional state improved in 11/15 patients, 4/15 patients showed no change, nevertheless these patients had reached a good recovery before surgery. Application of this technique is limited by cost, nonetheless it is recommended for extensive reconstruction of the skull.
We have reviewed 505 cases of surviving total hip replacement for primary osteoarthritis and studied the functional result and pain relief obtained between four and fourteen years after implantation. The risk factors were stratified and evaluated by multivariate statistical analysis. The patients were satisfied with the result of arthroplasty, and long-term function was improved in 95% of cases. The risk of postoperative hip pain was increased by knee pain, a snap-fit prosthesis with a 35 mm head, and a short wedge-shaped femoral stem, and by replacement at an early age. Function was impaired postoperatively by hip pain, bilateral hip disorders, intercurrent disease affecting locomotion and by old age at the time of surgery. The functional result was not related to the time from operation. The functional result after hip arthroplasty can be evaluated in a logical, unbiased and thorough way using multivariate statistical analysis.
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UNLABELLED: The authors present a new implant for vertebral body replacement in the thoracic and lumbar spine. The titanium implant is designated for reconstruction of the anterior column in injury, posttraumatic kyphosis or tumor of the thoracolumbar spine. The instrumentation has to be supplemented by a stabilizing implant. After positioning, the implant is distracted in situ, through which best contact to adjacent end-plates and 3-dimensional stability should be provided. The possibility of secondary dislocation or loss of correction should thereby be minimized. OBJECTIVES: We investigated the biomechanical 3-dimensional stability in vitro, using Synex in combination with an anteriorly (Ventrofix) or a posteriorly (USS) stabilizing implant. The differences between both stabilizing implants were to be determined. Synex was compared with the "Harms titanium mesh cage" (MOSS) as vertebral body replacement. METHODS: In a 3-dimensional spinal loading simulator, we determined the bisegmental (T12-L2) neutral zone (NZ), elastic zone (EZ), and range of motion (ROM) of 12 human cadaveric spines. After corpectomy of L1 we tested 4 groups of implant combinations: USS/Synex, USS/MOSS, Ventrofix/Synex, Ventrofix/MOSS. We analyzed the differences between each of the instrumentations as well as differences compared to the intact spine. RESULTS: In most directions, significantly higher stability was achieved with USS, compared with Ventrofix and the intact specimen. For axial rotation, with no instrumentation the stability of the intact spine was restored. With Synex a significantly higher stability was noted for extension, lateral bending, and axial rotation in comparison with the Harms cage. A tendency towards more stability for flexion was additionally observed with Synex. When using MOSS in combination with USS, it was necessary to perform a third operative step for induction of intervertebral compression via the posterior fixator. CONCLUSIONS: The posterior fixation was found to offer superior stability compared to the anterior one. Synex was at least comparable to MOSS for suspensory replacement of the vertebral body in the thoracolumbar spine. The evidence of higher biomechanical stability with Synex leads to the probability of a higher rigidity in vivo. Due to the distractability of Synex, a better intervertebral compression was achieved. Therefore, an additional tightening of the posterior fixator after insertion of Synex was not necessary, in contrast to the Harms cage.
This study investigated whether after a nucleotomy and implantation of a prosthetic disk nucleus (PDN) the original height and mobility of an L4/L5 disk can be restored. Compared to the intact state (100%), nucleotomy increased the median values of the normalized range of motion (ROM) in flexion/extension to 118%, lateral bending to 112%, and axial rotation to 121%. PDN implantation reduced ROM to 102%, 88%, and 90%. These differences were even more distinct when comparing the neutral zone (NZ) with 210%, 173%, and 107% after nucleotomy and 146%, 149%, and 44% after PDN implantation. With an axial preload of 200 N, disk height after nucleotomy was reduced by about 1.3 mm and could be restored with PDN implantation. PDN implantation can restore disk height and ROM after nucleotomy to normal values and reduce the strong NZ increase. Further biomechanical characterization of this therapy with PDN is necessary.
We report on the transcatheter closure of ventricular septal defects (VSD) in 26 patients with Amplatzer Occluders and Nit- Occlud Coil Systems. Twenty-one patients had a perimembranous and 5 patients a muscular VSD. Patients' age range was 5 months to 59 years (median 8 years) and their body weight 4.5 kg to 167 kg (median 28 kg). Defect diameters were 3-11 mm (median 5 mm). Sixteen patients had left ventricular volume overload and 7 patients pulmonary hypertension (median 50% of systemic pressure). Seven patients suffered from trivial or mild aortic regurgitation. Twenty-eight devices (4-12 mm; median 8 mm) were implanted (16 Amplatzer, 12 Nit-Occlud) through sheaths of 4F to 9F (median 7F). Fluoroscopy times were 8.3- 56.5 min (median 26.2 min). One coil was surgically explanted directly after intervention. One patient needed pulmonary banding due to additional VSDs. After a follow-up of 7 months (1-12 months), 2 patients had a small and 9 a minimal residual shunt. Thirteen defects were completely closed. Transcatheter closure of VSDs with new devices seems to be a promising therapy for suitable defects in different hemodynamic conditions in patients of every age.
UNLABELLED: In recent years many different systems for transcatheter closure of an atrial septal defect (ASD) have been developed and tested. However, all systems presently available have some special disadvantages. The recently introduced Amplatzer Septal Occluder (ASO), though, appears promising. It is a self-expanding and self-centering double disc made from a Nitinol mesh, which is tightly woven to give mechanical strength. Both discs are separated by a connecting cylindrical portion. Its diameter may be chosen, so that it corresponds to that of the ASD. Discs of polyester patches are sewn into the retention discs as well as into the cylindrical portion of the device in order to augment thrombogenicity. After measuring the diameter of the ASD with a balloon, an appropriate ASO is selected and advanced into the left atrium through a 7 or 8 French sheath. Then the distal disc and part of the connecting cylindrical portion is developed in the left atrium and pulled against the atrial septum, so that the cylindrical portion is occluding the ASD. Thereafter, proximal disc is deployed and the delivery cable disconnected. As long as the cable is connected to the device repositioning is easily achieved by pulling the device back into the sheath. Within a time period of 4 months in 29 out of 31 patients (median age: 12.1 years, median weight: 45.0 kg) complete closure of the ASD with a mean diameter of 11.0 mm (6-20 mm) was achieved without complications, the average fluoroscopy time being 8.3 min (2.9-21.5 min). Mean Qp:Qs was 1.5 (0.9-2.2). During a mean follow-up period of 2.1 months post implantation fixed seating of the ASO without residual shunt, arrhythmias, thrombembolic events and impairment of A-V valves was observed in all patients. CONCLUSION: The Amplatzer septal occluder allows quick, safe, and complete closure of atrial septal defects without complications if one adheres to strict implantation criteria. For a final judgement, however, long-term follow-up studies are necessary.
Titanium implants can be shaped by traditional hand forming, press shaping, modular construction by welding, construction on full-size models shaped from CT coordinates and, most recently, by computer-assisted design and computer-assisted manufacturing (CAD/CAM) that consist in the direct prefabrication of individual implants by milling them out of a solid block of titanium. The aim of our study was to present a set of preliminary cases of an ongoing program of reconstructive procedures of the skull base using titanium implants. The subjects underwent ablative procedures of the skull base with reconstruction either by titanium mesh or individual prefabricated CAD/CAM implants. Six patients have been operated on successfully since 2000: two received prefabricated CAD/CAM titanium plates and four others underwent reconstruction with titanium mesh. The stability of CAD/CAM plates is superior to that of mesh, thus it is more useful in reconstructing large lesions of the frontal skull base and the temporal and occipital bones. Titanium mesh was successfully used for defects smaller than 100 cm(2) or where selected viscerocranial defects are complicated in design and less reproducible by CAD/CAM. The intraoperative design, shaping and adjustment characteristic of titanium mesh can be dispensed with when CAD/CAM implants are used. The 3-D data set used in the CAD/CAM process also operates in the navigated simulation and planning of the ablation contours, the latter being of great assistance in establishing the optimal future defect. As a disadvantage, CAD/CAM technology is more expensive than titanium mesh, and the process is time-consuming as it is carried out in advance of surgery.
BACKGROUND: After presenting two sisters with the rare form of congenital arrhinia, this syndrome is reviewed, an explanation of the pathogenesis is offered and the therapeutic options of the functional and aesthetic reconstruction are discussed. DISCUSSION: In cases of congenital arrhinia different degrees of respiratory distress, cyanotic episodes, and impaired food intake are described. Therefore after birth respiration and food intake need to be monitored to alleviate the situation through intubation or tracheotomy. The following conclusions could be made based on the literature overview. Little is known about the pathophysiology and a great variety of therapeutic interventions and reconstruction solutions with a wide spectrum of complications are described. Due to the numerous forms of complications, which need to be compared with the reconstructive results, indications for surgical reconstruction of the airway and plastic reconstruction of the nose during childhood must be defined very stringently. CONCLUSION: One method to achieve a satisfactory plastic result is with an osseointegrated prosthesis. This facial prosthesis can be inserted without complications and can guarantee an adequate result, whereas no impairment of maxillofacial development was noted.
BACKGROUND: The preoperative manufacturing of individual skull implants using computer aided design (CAD) and computer aided manufacturing (CAM) is based on the use of titanium, although the use of other materials is also potentially possible. THE USE OF OTHER MATERIALS: The use of poly-(D,L-lactide) (PDLLA) as an implant material was investigated using an adult, formalin fixed sheep's head with a complex frontolateral defect. A standard individual titanium implant as well as a resection template made of aluminium were milled in order to allow bone resection and reconstruction within one operation. A mould was made of Teflon for the fabrication of the PDLLA implant using carbon dioxide at high pressure. This procedure allowed a critical comparison to be made of both implant materials and showed that the production of a biodegradable PDLLA implant is possible. At present the titanium implant is superior to the PDLLA implant, as PDLLA settled with slightly larger dimensions than the mould, although the structure itself was exact. DISCUSSION: The goal of the present research is the fabrication of a functionally graded material made of polylactide, polyglycolide, calcium phosphate and osteoinductive proteins using existing technology, which will meet all of the requirements for stability, resorption kinetics, biocompatibility, radiotranslucence and osteogenic potency of an ideal implant material.
Thirty-nine patients with maxillofacial defects were restored by prostheses. A questionnaire was completed both before and after the prosthetic rehabilitation, measuring such psychological aspects as changes in self-image, optimism, and feelings of health. Thirty-three patients were found to respond favorably. Improvement was most pronounced where the facial defect had been caused by trauma (accidents). It was less conspicuous in patients with congenital malformations, whereas oncologic patients' average experimental change was minimal. It is concluded that cancer patients require more than a well-fitting prosthesis for successful rehabilitation.
OBJECTIVES: We assessed the use of intracardiac echocardiography (ICE) as the primary means for both selection of the Amplatzer Septal Occluder (ASO) and the guidance of transcatheter closure of secundum atrial septal defects (ASDs). BACKGROUND: The standard method for transcatheter closure of ASDs requires balloon-sizing maneuver and transesophageal echocardiographic (TEE) monitoring. The role of ICE during transcatheter closure of ASDs has not yet been established. METHODS: In 91 patients with ASDs, two standardized orthogonal sections were used to obtain ICE-derived measurements of the fossa ovalis and to assess optimal device deployment: the transverse section on the aortic valve plane, and the longitudinal section on the four-chamber plane. RESULTS: In all patients, ICE planes were identified with excellent resolution, providing proper measurements of the fossa ovalis, from which to derive geometric assumptions for the selection of an appropriately sized device. The ASO waist diameter was chosen on the basis of the r value (r = [square root c(2) + p(2)], where r is the radius of an ideal circle that intersects the elliptical fossa ovalis in its semi-latus rectum, c is the foci half-distance of the fossa ovalis, and p is its semi-latus rectum). During the procedure, the four-chamber plane allowed us to obtain easily interpretable images of all stages of device deployment. Midterm complete occlusion rate was 97.8%. No ICE-related complications occurred. CONCLUSIONS: The ICE evaluation of ASDs allows quantitative and qualitative information for both proper ASO selection and optimal device placement, thus eliminating the cumbersome balloon-sizing maneuver and the need for general anesthesia during TEE monitoring.