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Biomedical subjects

Edgar Biemer

Publications and source records attributed to Edgar Biemer.

17 recordsLinked to original sources
PubMed2006

Comparison between breast volume measurement using 3D surface imaging and classical techniques.

Quantification of the complex breast region can be helpful in breast surgery, which is shaped by subjective influences. However, there is no generally recognized method for breast volume calculation. Three-dimensional (3D) body surface imaging represents a new alternative for breast volume computation. The aim of this work was to compare breast volume calculation with 3D scanning and three classic methods, focusing on relative advantages, disadvantages, and reproducibility. Repeated breast volume calculations of both breasts in six patients (n=12) were performed using a 3D laser scanner, nuclear magnetic resonance imaging (MRI), thermoplastic castings, and anthropomorphic measurements. Mean volumes (cc) and mean measurement deviations were calculated, and regression analyses were performed. MRI showed the highest measurement precision, with a mean deviation (expressed as a percentage of mean breast volume) of 1.56+/-0.52% compared with 2.27+/-0.99% for the 3D scanner, 7.97+/-3.53% for thermoplastic castings, and 6.26+/-1.56% for the anthropomorphic measurements. Breast volume calculations using MRI showed the best agreement with 3D scanning measurement (r=0.990), followed by anthropomorphic measurement (r=0.947), and thermoplastic castings (r=0.727). Compared with three classical methods of breast volume calculation, 3D scanning provides acceptable accuracy for breast volume measurements, better spatial interpretation of the anatomical area to be operated on (due to lack of chest deformation), non-invasiveness, and good patient tolerance. After this preliminary study and further development, we believe that 3D body surface scanning could provide better preoperative planning and postoperative control in everyday clinical practice.

Adult↗
PubMed2006

Amnion cells engineering: a new perspective in fetal membrane healing after intrauterine surgery?

In this study we aimed to set up an in vitro culture of the rabbit amnion in order to support in vivo fetal membrane healing capacity following fetoscopy. Fetal membranes were collected from a mid-gestational rabbit, and cultured on collagen support material for 14 days. 34 rabbits at 22-23 days gestational age (GA) underwent fetoscopy. The entry site was randomly allocated to 4 closure technique study groups: group I, human amnion membrane (n = 23); group II, collagen foil (n = 16); group III, collagen plug (n = 19), and group IV, collagen plug with cultured amnion cells (n = 19). In all groups membrane access sites were additionally sealed with fibrin sealant, and the myometrium was closed with sutures. Fetal survival, amnion membrane integrity, and the presence of amniotic fluid were evaluated at 30 days GA. Cultures showed good survival in the collagen support material. Increased cellularity, survival and proliferations were observed. The amnion at the access site resealed in 58-64% of cases in groups II-IV, but none of the tested techniques was significantly better than the other. Histological examination indirectly revealed the anatomic repair of the membranes, since no entrapment of the membranes could be demonstrated in the myometrial wound.

Amnion↗
PubMed2006

Optimization of 3-dimensional imaging of the breast region with 3-dimensional laser scanners.

The anatomic conditions of the female breast require imaging the breast region 3-dimensionally in a normal standing position for quality assurance and for surgery planning or surgery simulation. The goal of this work was to optimize the imaging technology for the mammary region with a 3-dimensional (3D) laser scanner, to evaluate the precision and accuracy of the method, and to allow optimum data reproducibility. Avoiding the influence of biotic factors, such as mobility, we tested the most favorable imaging technology on dummy models for scanner-related factors such as the scanner position in comparison with the torso and the number of scanners and single shots. The influence of different factors of the breast region, such as different breast shapes or premarking of anatomic landmarks, was also first investigated on dummies. The findings from the dummy models were then compared with investigations on test persons, and the accuracy of measurements on the virtual models was compared with a coincidence analysis of the manually measured values. The best precision and accuracy of breast region measurements were achieved when landmarks were marked before taking the shots and when shots at 30 degrees left and 30 degrees right, relative to the sagittal line, were taken with 2 connected scanners mounted with a +10-degree upward angle. However, the precision of the measurements on test persons was significantly lower than those measured on dummies. Our findings show that the correct settings for 3D imaging of the breast region with a laser scanner can achieve an acceptable degree of accuracy and reproducibility.

Breast↗
PubMed2006

New aspects of breast volume measurement using 3-dimensional surface imaging.

Precise and objective calculation of breast volume is helpful to evaluate the aesthetic result of breast surgery, but traditional methods are unsatisfactory. Three-dimensional (3D) scanning of the body surface allows reproducible and objective assessment of the complex breast region but requires further investigation before clinical application. The main goal of this study was to investigate the precision and accuracy of breast volume measurement using 3D body scanning. Five independent observers standardized the 3D scanning method using 2 dummy models (n = 200) and examined its applicability with 6 test subjects and 10 clinical patients (n = 2220). Breast volume measurements obtained with the 3D-scanner technology were compared with reference measurements obtained from test subjects through nuclear magnetic resonance imaging. The mean deviation of the breast volume measurements of 1 test subject by all observers, expressed as percentage of volume, was 2.86 +/- 0.98, significantly higher than the deviation for the dummy models, 1.65 +/- 0.42 (P < 0.001). With respect to all clinical patients, the mean measurement precision obtained preoperatively was less precise than that obtained postoperatively (3.31 +/- 1.02 versus 1.66 +/- 0.49, respectively). Interobserver differences in measurement precision were not statistically significant. The mean breast volumes obtained by nuclear magnetic resonance imaging (441.42 +/- 137.05 mL) and 3D scanning (452.51 +/- 141.88 mL) significantly correlated (r = 0.995, P < 0.001). Breast volume measurement with 3D surface imaging represents a sufficiently precise and accurate method to guarantee objective and exact recording.

Breast↗
PubMed2006

Three-dimensional cephalometric evaluation of maxillary growth following in utero repair of cleft lip and alveolar-like defects in the mid-gestational sheep model.

OBJECTIVE: To evaluate maxillary growth following in utero repair of surgically created cleft lip and alveolar (CLA)-like defects by means of three-dimensional (3D) computer tomographic (CT) cephalometric analysis in the mid-gestational sheep model. METHODS: In 12 sheep fetuses a unilateral CLA-like defect was created in utero (untreated control group: 4 fetuses). Four different bone grafts were used for the alveolar defect closure. After euthanasia, CT scans of the skulls of the fetuses, 3D reconstructions, and a 3D-CT cephalometric analysis were performed. RESULTS: The comparisons between the operated and nonoperated skull sides as well as of the maxillary asymmetry among the experimental groups revealed no statistically significant differences of the 12 variables used. CONCLUSIONS: None of the surgical approaches used for the in utero correction of CLA-like defects seem to affect significantly postsurgical maxillary growth; however, when bone graft healing takes place, a tendency for almost normal maxillary growth can be observed.

Alveolar Process↗
PubMed2005

Neovascularization in prefabricated flaps using a tissue expander and an implanted arteriovenous pedicle.

Creating prefabricated flaps using tissue expanders in combination with the implantation of maximal blood flow vascular pedicles into suitable tissue areas represents a new tendency in the reconstruction of large skin defects. In 42 Chinchilla Bastard female rabbits weighing 3,700-4,600 g, skeletonized arteriovenous pedicles with maximal blood flow, dissected from the femoral and saphena magna bundles, were implanted underneath abdominal fasciocutaneous flaps. Oval tissue expanders of 250 ml were placed and fixed on the abdominal wall to expand these prefabricated flaps. The evaluation parameters were macroscopic observation, blood analysis, selective microangiography, histology, and scintigraphy. The study results showed that neovascularization in expanded prefabricated flaps was established from newly formed vessels generated from the implanted pedicles and their vascular connections with the originally available vasculature in the flap. After 20 days of prefabrication, the entirety of the expanded prefabricated flaps was perfused by blood flow supplied from newly implanted arteriovenous pedicles. The study indicated that an expanded prefabricated flap can be successfully created by the simultaneous implantation of a maximal blood flow pedicle in combination with flap expansion.

Animals↗
PubMed2005

Proposed new method for angiographically quantifying neovascularization in prefabricated flaps.

Prefabricated flaps have many potential applications in plastic and reconstructive surgery. Despite numerous experimental investigations and clinical applications, a standard quantification procedure for analyzing neovascularization in prefabricated flaps has not yet been established in the literature. In this study, we developed a new method for quantifying neovascularization, using a standard integral line plate including 25 evenly spaced lines corresponding to a 15-cm flap length, which was subsequently analyzed under a 2x magnification loupe. Vessel quantity was determined by counting the total number of times that vessels perfused by Micropaque intersected the integral lines over the entire surface of the flap. This new method was used for quantifying neovascularization in 156 prefabricated flaps, and we concluded that this technique is very simple and useful, allowing precise determination of the amount of neovascularization in prefabricated flaps on angiograms. Based on this principle, the quantification of neovascularization in any size of prefabricated flap can be easily performed using suitably modified integral line plates corresponding to the various flap dimensions.

Angiography↗
PubMed2005

Three-dimensional fetal cephalometry: an evaluation of the reliability of cephalometric measurements based on three-dimensional CT reconstructions and on dry skulls of sheep fetuses.

AIM: To develop a 3D CT cephalometric analysis for maxillary growth evaluation of sheep fetuses operated in utero, and to evaluate the reliability of this analysis by comparing it with a direct cephalometric analysis on dry skulls. MATERIAL AND METHODS: Five skulls of operated sheep fetuses were used, which after preparation were CT scanned and a 3D reconstruction was performed. A cephalometric analysis was performed directly on the dry skulls as well as on the reconstructed 3D CT images. In total, 56 linear distances were measured. In order to access the error of the method, the procedure was repeated after a 2 week interval. RESULTS: The comparison between the direct cephalometric and the 3D CT analysis revealed that only 5 variables were significantly different. The evaluation of the error of method revealed that 7 variables of the direct cephalometric analysis and none of the 3D CT analysis differed significantly. CONCLUSIONS: According to the results of this study, it can be concluded that a cephalometric analysis on 3D CT reconstructed images of the skulls includes fewer identification errors and seems to be an accurate and reliable method that could be regarded at least as equivalent to conventional cephalometry.

Animals↗
PubMed2005

Patterns of subchondral bone mineralization in the distal radioulnar joint.

PURPOSE: Studies have shown that it is possible to derive direct knowledge about the actual mechanical conditions of the wrist by analyzing the subchondral mineralization. The aim of the present study was to evaluate the distribution of the subchondral bone mineralization of the distal radioulnar joint (DRUJ) noninvasively in living subjects by using computed tomography (CT) osteoabsorptiometry to gain new information about the long-term loading conditions. METHODS: Twenty-two wrist joints were investigated in 11 healthy young subjects by means of CT osteoabsorptiometry. The CT scans of the DRUJ were taken in the axial plane in neutral position of the forearm and in both maximum pronation and supination. The CT datasets of 1.5-mm sections were obtained and then transferred to an image-analyzing system. The subchondral bone plate in each section was isolated, reconstructed in 3 dimensions, and converted into a false color series. RESULTS: The maximum subchondral bone density in the sigmoid notch of the radius was found along the distal border in all wrists. It was located dorsally in 10 wrists, palmarly in 8 wrists, and centrally in 4 wrists. The maximum bone density on the corresponding articular surface of the ulna was found dorsally in 10 cases, centrally in 8 cases, and palmarly in 4 cases. In 13 cases the maximum bone density was found in direct opposition on radius and ulna in neutral position. A statistically significant difference could not be detected in subjects with an ulna minus variance nor in those with a DRUJ angulation greater than 10 degrees . CONCLUSIONS: Our results show that in the sigmoid notch the load is transmitted through either the dorsal or palmar parts of the joint. In contrast the maximum bone density on the side of the ulna was found dorsally and centrally. We conclude that the ulna receives the maximum load in neutral position and supination, whereas because of the dorsopalmar translation of the ulnar head the radius may lead the ulna with either its palmar or dorsal borders during pronosupination. The ligamentous apparatus, the shape of the joint, and the ulna variance, however, may influence load transmission.

Adult↗
PubMed2005

Study of the neovascularisation of prefabrication of flaps using a silicone sheet and an isolated arterial pedicle: experimental study in rabbits.

Use of an isolated artery as an implanted pedicle in prefabricated flaps has rarely been reported either clinically or experimentally. In Chinchilla Bastard rabbits (n = 36), we dissected an isolated arterial pedicle from the femoral and saphenous artery, anastomosed it end-to-end to the femoral vein at the inguinal ligament and created an isolated arterial loop pedicle. This was implanted and fixed with polyglactin 9/0 under a random-pattern vascularised abdominal fasciocutaneous flap. The neovascularisation in the prefabricated flaps was evaluated macroscopically, by blood analysis, selective microangiography, and histology. The results showed a progressive degree of neovascularisation that corresponded to the increasing length of time that the pedicle was implanted in the flaps. Twenty days after prefabrication, the abdominal fasciocutaneous flap was readily perfused by the blood supply from the arterial pedicle. The capacity of the vessels in this group as seen on angiograms had increased to 258 vessels (108%) compared with the control group (239 vessels, 100%).

Anastomosis, Surgical↗
PubMed2004

Intrauterine autogenous foetal bone transplantation for the repair of cleft-like defects in the mid-gestational sheep model.

AIM: The success of intrauterine surgery in treating non-life-threatening malformations such as myelomeningocoele, has also renewed strong interest in using this technique for treating craniofacial malformations. Nevertheless, the only experimental cleft-like defect models known, are those concerning wound healing of soft tissues. MATERIAL AND METHODS: Attempts were made to repair artificial cleft-like defects including transplantation of 11 autogenous foetal bone grafts from the iliac crest or ulna, and were randomly assigned to three study groups, using the mid-gestational sheep model. In a 4th study group, lyophilized collagen, a bone-regenerating bioresorbable implant material, was used to fill the alveolar defect. RESULTS: In all groups, there was a slight degree of asymmetry and thinning of the lip. Radiological studies demonstrated a variable degree of abnormality of the maxilla, ranging from none to a mild deviation. Three-dimensional computer tomography, two-dimensional maximal intensity projection findings, and histological analysis confirmed bony healing of the alveolar cleft-like defect. DISCUSSION/CONCLUSION: Intrauterine autogenous foetal bone transplantation for the repair of cleft-like defects in the sheep is feasible. This is a reliable and valuable model toward a possible clinical application for intrauterine treatment of clefts.

Absorbable Implants↗
PubMed2004

Ulnar variance and subchondral bone mineralization patterns in the distal articular surface of the radius.

PURPOSE: Based on biomechanical experiments in specimens it is accepted widely that ulnar length determines loading of distal articular surface of the radius with ulna-minus variance increasing and ulna-plus variance decreasing the loading of the lunate compartment. Nevertheless a direct assessment of the actual loading conditions in the living is currently impossible. The aim of the present study is therefore to evaluate subchondral bone mineralization patterns to provide further information about the role of ulnar length in load transmission through the radiocarpal joint. METHODS: Twelve wrists of healthy subjects with an average age of 33 years and an average congenital ulna-minus wrist of -2.8 mm (range, -4 to -1 mm) were examined by means of computed tomography-osteoabsorptiometry. A further 5 wrists in healthy subjects with an average age of 52 years and an average congenital ulna-plus variance of +3.0 mm (range, +2 to +4 mm) were examined with the same technique. Seventeen wrist joints of 9 healthy subjects with ulna-zero variance were examined in the control group. RESULTS: The results show a mainly lunate mineralization pattern in subjects with ulna-minus wrists in 75% of the cases, which is more frequent than in subjects with ulna-zero wrists. The results in ulna-plus variance show a mainly scaphoid mineralization pattern in 100% of cases. The differences in mineralization patterns are statistically significant. CONCLUSIONS: We conclude from these morphologic results in living subjects that ulnar length determines the peak mineralization patterns of the distal articular surface of the radius with a relatively lesser loading of the lunate fossa in ulna-plus variance and a relatively higher loading history in most cases of ulna-minus variance. The hypothesis, however, that ulna-minus variance is always a sign of a relatively higher loading history of the lunate fossa cannot be supported.

Absorptiometry, Photon↗
PubMed2004

Clinical outcome and patients' satisfaction after simultaneous bilateral breast reconstruction with free transverse rectus abdominis muscle (TRAM) flap.

In the study presented, the long-term outcome and satisfaction of 34 patients who underwent simultaneous bilateral breast reconstruction with a free transverse rectus abdominis muscle (TRAM) flap between 1988 and 2001 were assessed. Flap complications affected 13 of 68 flaps (19.1%). Anastomosis revision was needed in 6 cases (8.8%), the salvage rate being 50%. The rates of total and partial flap loss were 4.4% and 1.5%, respectively. Bilateral flap loss did not occur. Four patients developed donor site complications (11.7%), with wound healing problems being the most common (5.8%). Most patients were satisfied with their decision to have had breast reconstruction with free TRAM, 91% would choose the same operation again, and 91% would recommend this procedure to other patients. Of the operated patients, 20.8% felt an improvement in their sexual life; more patients, however, reported an improvement concerning their social life (37.5%) and life in general (50%).

Adult↗
PubMed2002

Donor site morbidity after harvest of free osteofasciocutaneous fibular flaps with an extended skin island.

Since 1993, a total of 41 free osteofasciocutaneous fibular flaps with an extended skin island (average dimensions, 16.9 cm long [range, 12-22 cm] x 10.7 cm wide [range, -16 cm], or 180.8 cm [range, 112-352 cm ]) have been used in by the authors in various clinical applications. To evaluate donor site morbidity, the 41 patients involved were asked to answer a questionnaire and to present themselves for clinical and radiological examination. The subjective findings reported by these patients, and the examinations, showed that donor site morbidity was moderate. Apart from some occurrence of mild edema and pain, as well as modest motor weakness of the great toe, and deficiency of distal nervous segments, only 7 patients were found to have a slightly positive anterior drawer of the talus (anterior subluxation of the talus), but no instability. In conclusion, donor site morbidity after harvest of osteofasciocutaneous fibular flaps for different clinical indications, where extended skin islands were needed, is moderate.

Adult↗
PubMed2002

Long-term fate of the bony component in neophallus construction with free osteofasciocutaneous forearm or fibula flap in 18 female-to-male transsexuals.

Female-to-male transsexuals have been operated on in the authors' department since 1975. Between 1981 and 1995, 46 patients underwent neophallus construction with a free osteofasciocutaneous forearm or fibula flap. The bony part of these flaps is embedded in tissue with excellent blood circulation, has no contact with the skeleton, and is free of mechanical stress. To evaluate the long-term fate of the bony component of these flaps, the authors examined 18 of the 46 patients (39.1 percent) who had received a neophallus by means of one of these methods (12 with forearm and six with fibula flap) and who were willing to participate in the updating of the results of the previous two decades; this represented a follow-up of 5 to 112 months postoperatively (average, 27.4 months). The following investigations were undertaken: clinical and radiologic examination, bone scintigraphy, magnetic resonance imaging, and histologic examination of the neophallus bony component. In all patients, the clinical examination showed no significant variations in the shape and rigidity of the neophallus bone. The radiologic examination showed a compact bone structure, and the magnetic resonance imaging proved the vitality of the neophallus in all patients, with no significant changes over time. Bone scintigraphy did not prove to be useful in determining the long-term fate of the neophallic bony component. Histologically, subperiosteal neoformation of fibrous bone was shown, whereas the lamellar cortical bone was predominantly avital. The results of this study reveal the vitality of the bony component in neophallus construction with free osteofasciocutaneous flaps. Even 112 months after the procedure, it provided sufficient stiffness for sexual intercourse. This continuing adequate rigidity of the bony component, in addition to the well-known advantages of the free osteofasciocutaneous flap, is further evidence of its usefulness in neophallus construction.

Female↗