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At least 829 records · Page 46Linked to original sources
PubMed1991

[Autologous corium-plasty in closure of muscle hernia. A case report].

The case involving a 33-year-old patient is presented who developed a muscle hernia through a fascia late defect subsequent to removal of internal fixation devices from the left femur. Because primary closure of the fascia could not be achieved, an autologous dermis graft harvested from the margin of the skin incision was used. A firm closure of the fascial gap was achieved and the patient has no complaints. Having used an autologous dermis graft, we were able to avoid an alloplastic substitute.

Adult↗
PubMed1999

Alternatives to tracheostomy in infants and children with obstructive sleep apnea.

PURPOSE: Since 1989, 70 children have been treated surgically with varying degrees of obstructive sleep apnea (OSA). Of these, 29 patients had completely failed conventional medical and surgical treatment and were considered tracheostomy (T) candidates, whereas five had previously undergone T for severe OSA as infants and did not respond to standard decannulation protocols. The preoperative diagnoses were cerebral palsy (n = 5), Down's syndrome (n = 5), hemifacial microsomia (n = 4), Pierre Robin sequence (n = 6), and a mixed group of craniofacial disorders (n = 14). The patients ranged in age from 2.5 weeks to > or =18 months (mean, 7.32 years). Preoperatively, four patients were on ventilators and one suffered a cardiac arrest, attesting to the severity of OSA. METHODS: To enlarge the caliber of the airway, each patient underwent an aggressive surgical treatment protocol. All sites of upper airway obstruction were treated simultaneously by a combination of craniofacial skeletal expansion and soft-tissue reduction. RESULTS: Tracheostomy was avoided in 90.4% of patients. Temporary or "permanent T" were required in three patients (9.6%). One patient with cerebral palsy had recurrent OSA and died. A second patient with severe laryngotracheomalacia and retrognathia who did not respond to apnea surgery underwent a tracheostomy and ultimately died of pulmonary causes. Four patients (7.8%) required supplemental home oxygen or continuous positive airway pressure. The average preoperative respiratory disturbance index, defined as the average number of apneic and hypopneic events per hour of sleep, dropped from 25.9 to 4.4 after surgery. The average lowest recorded oxygen saturation during overnight polysomnography rose from 61% to 92% after surgery. Of the five patients with permanent T, four had thus far been decannulated. Complications occurred in 10 patients, 50% of which were related to minor problems with mandibular distraction devices. CONCLUSION: Our results confirm the efficacy of an aggressive surgical approach to the treatment of OSA in children, avoiding the necessity for tracheostomy or permitting decannulation of permanent T in the majority of cases.

Child↗
PubMed2004

The mechanical consequences of mineralization in embryonic bone.

The purpose of this study was to examine the effect of mineralization on the mechanical properties of embryonic bone rudiments. For this purpose, four-point bending experiments were performed on unmineralized and mineralized embryonic mouse ribs at 16 and 17 days of gestational age. Young's modulus was calculated using force-displacement data from the experiment in combination with finite element analysis (FEA). For the unmineralized specimens, a calculated average for the Young's modulus of 1.11 (+/- 0.62) MPa was established after corrections for sticking to the four-point bending device and aspect ratio, which is the ratio between the length of the bone and its diameter. For the mineralized specimens, the value was 117 (+/- 62) MPa after corrections. Hence, Young's moduli of embryonic bone rudiments increase by two orders of magnitude within 1 day, during endochondral ossification. As an effect, the hypertrophic chondrocytes in the calcifying cartilage experience a significant change in their mechanical environment. The chondrocytes are effectively stress shielded, which means that they do not carry stresses since stresses are supported by the stiffest parts of the tissue, which are in this case the diaphyseal cortex and the calcified matrix. The deformability of the hypertrophic chondrocytes is, therefore, severely reduced. Since the transition is so sudden and enormous, it can be seen as a process of 'catastrophic' proportion for the hypertrophic chondrocytes. The subsequent resorption of calcified cartilage and the expansion of the marrow cavity could be consequential to stress shielding.

Animals↗
PubMed2000

Distraction osteogenesis for craniosynostosis.

OBJECT: The authors describe the use of distraction devices and surgical techniques of distraction osteogenesis for the treatment of patients with craniosynostosis. METHODS: Since 1994, the authors have performed distraction procedures in 23 patients with craniosynostosis in whom osteogenesis was achieved. Thirteen of the 23 patients underwent a complete Le Fort III midface osteotomy and distraction. In 10 patients the distraction osteogenesis involved the cranial bone; six underwent combined forehead and midface distraction (Le Fort IV distraction) in which multiple internal devices were used after performing a Le Fort IV osteotomy. An external distraction procedure was used to treat the first two cases. Since 1996, the authors have used internal devices developed in their unit. Distraction was initiated 1 week after the osteotomy at the rate of 0.5 mm per day for the cranium and 1.0 mm per day for the midface. The consolidation phase after distraction was initiated was 2 to 3 months. No major complications such as intracranial infection or neurological deficits were observed during the course of distraction osteogenesis. The osteogenesis generated at the distraction site was considerably satisfactory; and recurrence of the deformity in the follow-up period was minimal. CONCLUSIONS: Distraction osteogenesis for craniofacial deformity has numerous advantages: 1) bone grafting is unnecessary; 2) the procedure is less invasive, has short operating time, and less blood loss occurs than in conventional craniofacial procedures; 3) no intracranial dead space is created; 4) there is a good amount of blood flow to the bone segment; and 5) soft-tissue expansion occurs. The authors believe that distraction osteogenesis is a versatile and stable option for the treatment of patients with craniosynostosis.

Adolescent↗
PubMed2000

Techniques for management of size discrepancies in microvascular anastomosis.

Size discrepancy in microvascular anastomosis is a common issue in free flap transfer. The sudden change of caliber may cause turbulence to the blood flow and predisposes to platelet aggregation. Discrepancies in the cut end diameters have been managed by many geometrical methods in order to reduce the risk to thrombosis. In this paper, we pretended to summarize the techniques described and published about the management of size discrepancies in microvascular anastomosis, from the simple mechanical expansion with the jeweler's forceps to the sophisticated hardware such as devices or laser. Advantages and disadvantages are analyzed for many geometrical designs of anastomosis. We may conclude there is not an ideal technique to manage every size discrepancy, rather to question for the best method with the less complications, we should search for the best procedure to fit a specific case. A small caliber discrepancy may be well managed only with mechanical expansion. In traumatic or ischemic leg reconstruction, an end to side anastomosis will offer the continuity of the blood flow to both the vessel and the flap. In head and neck reconstruction, when a great discrepancy may be anticipated and the upstream donor vessel is smaller than the recipient one, a sleeve anastomosis can be performed. In the clinical set of a gap between the vessel ends, a graft must be used. Other geometrical designs (fish mouth or oblique cut), devices, glues or adhesives and laser helped anastomosis should be considered according the surgeon experience.

Anastomosis, Surgical↗
PubMed2000

[Mechanics of palatal expansion in the occlusal plane].

The mechanics of a transpalatal arch in the occlusal plane (symmetrical V-bends, asymmetrical V-bends and step-bends) is studied through four methods: simulation of the teeth movements with a typodont, measure of the forces and the moments with a mechanical system composed of pulleys and dead load devices, photo-elastic stress analysis, finite element stress analysis. Typodont experimentations display the dental movements: the easiest one is rotation; it is more difficult to observe distalization and mesialisation that occur with a version of the tooth. An experimental apparatus, composed of pulleys and dead load devices, allows to measure forces and moments released by a transpalatal arch, depending on the level of the activations. The authors notice that the distalization force for an asymmetrical V-bend activation is low, about 0.2 Newton for 5 degrees of activation. Photo-elastic stress analysis affords a visualization of the shear stresses induced by a transpalatal arch within the supporting structures of a root, thanks to the observation of colored fringes in a model constituted with two molars included in a birefringent resin. Meanwhile, the manipulation of the photo-elastic resin is not easy and the interpretation of the results remains difficult. The finite element method is a numerical analysis and consists in the fragmentation of the studied structure in a certain number of elements, where forces and moments can be applied: the three dimensional program analyses the stress and strains in these elements. Thus, we can: 1.--visualize strains and stresses of a transpalatal arch, when it is inserted in the lingual molar sheaths; 2.--observe the dental movements due to the activations of the transpalatal arch (rotation, version, mesialisation, distalization); 3.--study the stress induced in the periodontal tissue. The results of these studies are complementary and in agreement. Particularly, the second method (measure of forces and moments) and the finite element method provide a mathematical and visual model that could explain clinical results: thus, the main purpose of this research is to understand the orthodontic mechanics used in the edgewise or segmented technique.

Adult↗
PubMed1999

Maxillary distraction in cleft lip palate patients: a review of six cases.

Cleft lip and palate patients can present with a maxillary retrusion with tendency to Class III malocclusion after cleft repair. Maxillary distraction osteogenesis is a technique that provides simultaneous skeletal advancement and expansion of the soft tissues. Six nonsyndromic cleft lip and palate patients, ages 12 to 16 years (mean, 13.8 years), underwent maxillary distraction; four had a unilateral and two a bilateral cleft lip and palate. After an incomplete LeFort I osteotomy; a latency period of 3 days was respected. On Postoperative Day 4, distraction was initiated through anterior traction on a Delaire facial mask using distraction forces of 900 gm. Photographs and lateral cephalometric radiographs were obtained preoperatively and 4 months after distraction. A cephalometric analysis was performed to compare the sagittal dentocraniofacial morphology before and after distraction. The aesthetic improvement obtained by maxillary distraction osteogenesis during the permanent dentition to correct maxillary retrusion in our cleft lip and palate patients was impressive. Skeletal advancement varying from 1 to 3.5 mm (mean, 1.7 mm) was found. However, significant dentoalveolar compensations occurred in three patients. This was due to the dental anchorage of the distraction device and can be avoided only by the use of skeletal fixation.

Adolescent↗
PubMed2001

The "Nordstrom suture" to enhance scalp reductions.

The authors compared the results of 10 scalp reductions using the "Nordstrom suture" with the earlier published results of scalp reductions without a device to prevent stretch-back and of reductions with extenders. At 1 month postoperatively, the Nordstrom suture eliminated the stretch-back of 8.3 mm seen in earlier studies and, in fact, it shrank the bald area. The average shrinking achieved with the Nordstrom suture was 16.9 mm (i.e., 143 percent improvement over scalp reductions alone). Scalp extenders shrank the bald area, but the Nordstrom suture shrank the area about three times more than extenders at 1 month postoperatively.

Alopecia↗
PubMed2002

[Clinical results of skeletal class III malocclusion in 11 children aged from 10 to 14 years].

OBJECTIVE: The aim of this study is to investigate the clinical effects of combined protraction facemask and rapid maxillary expansion in the treatment of Class III malocclusion in 11 children aged from 10 to 14 years. METHODS: The observation group included 11 subjects in late mixed dentition or early permanent dentition, and the control group included 32 subjects in early mixed dentition. Protraction facemask and rapid maxillary expansion device was used and the mean treatment time was 6 months. Cephalometric radiographs were taken at the initiation of treatment (T1) and after 6 months of treatment (T2). In this way,(T2-T1) represented cephalometric changes after the treatment and cephalometric analysis based on a new basecranical reference system was used to compare the changes. RESULTS: All the subjects had the following changes: the maxilla moved forward,the mandible exhibited a downward and backward rotation and the forward growth was restricted. The overjet correction of the observation group was 5.3mm, 51% of the overjet correction was due to skeletal changes and 49% due to dental changes.9 cases obtained normal overjet and overbite and molar relationship. CONCLUSION: The combination of protraction facemask and rapid maxillary expansion is helpful to the correction of Class III malocclusion in children aged from 10 to 14 years. It can alleviate the degree of deformation,avoid surgery, and improve the relationship between hard and soft tissue.

English Abstract↗
PubMed1998

Measurement of the expansion of the calcaneal fat pad upon weightbearing.

The width of the calcaneal fat pad during weightbearing differs from its width during nonweightbearing. In this study, the medial-to-lateral width of the calcaneal fat pad was measured during weightbearing as well as nonweightbearing, and the two measurements were compared. The difference between weightbearing width and nonweightbearing width was found to vary widely across individuals. This measurement has implications for the manufacture of functional foot orthoses, which are made from nonweightbearing impressions of the foot. The significance of the authors' findings with regard to patient comfort is discussed.

Adipose Tissue↗
PubMed2002

Rapid alignment of collagen fibers in the dermis of undermined and not undermined skin stretched with a skin-stretching device.

A controlled, quantitative histochemical study was performed in five piglets to establish changes in undermined and not undermined stretched skin. The skin was stretched with a stretching device for 30 minutes to close a large skin defect. On each flank of the piglet, at a standard position, 9 x 9-cm wounds were created under general anesthesia. On one flank, the surrounding skin was undermined cranially and caudally over a 10-centimeter area. Sections of skin biopsies obtained during stretching were stained with picrosirius red and studied with routine light microscopy and polarized light microscopy in combination with image analysis. The length of collagen fibers was analyzed as a parameter of changes in the dermis resulting from skin stretching. This newly developed quantitative method appeared to be valid, specific, and reproducible, allowing for objective determination of changes in the length of the fibers in the plain of the sections. Changes in the orientation of collagen fibers in the dermis as a result of skin stretching were thereby determined. Epidermal thickness did not change significantly under the influence of stretching forces in both undermined and not undermined skin. However, the orientation of the collagen fibers changed significantly as a result of skin stretching. In undermined wounds, parallel alignment and elongation of the fibers in the plane of the sections was already observed after 15 minutes of stretching. The fibers became aligned in the direction of the stretching force, perpendicular to the wound margin. After 30 minutes of stretching, the mean major axes of the collagen fibers were longest in the plane of the sections (p < 0.001). This meant that elongation and parallel alignment of the collagen fibers had occurred. Stretching of not undermined skin for 15 minutes resulted in significantly stronger parallel alignment in the plane of the sections as compared with undermined skin. This was less well defined after 30 minutes of stretching in not undermined skin. It is concluded that skin stretching with a skin-stretching device for 30 minutes results in significant histomorphological changes of collagen fibers in the dermis of both undermined and not undermined skin. The fibers realign rapidly as a result of stretching forces and become aligned in the direction of the stretching force, perpendicular to the wound margin. These dynamic changes in collagen fibers explain the significantly decreased wound closing tension resulting from skin stretching and explain how skin stretches beyond its inherent extensibility.

Animals↗
PubMed1997

Implementation of parameters in the expansion ratio of mesh skin grafts.

Expansion of a mesh skin graft depends on factors pertaining to the graft itself as well as on parameters of the meshing device. With regard to the graft, we examine the efficiency of graft handling and thickness of the skin graft. With regard to the parameters of the meshing apparatus, which determine the expansion ratio: (1) d equals the distance between the cutting blades, which will become the width of the mesh ribbons and is an underestimated parameter for expansion; and (2) L equals the length of cut, which determines proportionally the expansion ratio. This length defines the maximal distance of the raw square of the expanded mesh and therefore the healing time by epithelialization. The authors present a mathematical formula of expansion ratio that allows for an objective comparison of skin meshing apparatuses. It is concluded that optimal mesh skin grafting is based on mathematical principles rather than on inventive instrumentation. Furthermore, an analysis of the mechanical parameters as given by the manufacturers is important in anticipating healing time per expansion ratio.

Humans↗
PubMedDate not supplied

Dosimetry of a 188rhenium-labeled self-expanding stent for endovascular brachytherapy in peripheral arteries.

PURPOSE: Radioactive stents have been proposed as endovascular irradiation device to prevent in-stent restenosis by inhibiting neointimal proliferation. 32P-stents have been used in several studies so far, but require large-scale labeling procedures and endovascular barotrauma for stent expansion supporting the development of edge restenosis. Purpose of this study was to establish dosimetry of a self-expanding nitinol stent for peripheral vascular disease, which was radiolabeled with 188rhenium (188Re) by a dip coating technique. METHODS AND MATERIALS: The surface of nitinol Memotherm FLEXX stents was polymer-coated providing functional NH(2) groups for diethylenetriaminepentaacetic acid (DTPA) binding, providing the ligand for the complexation of 188Re onto the stent surface. Stability of radiolabeling was tested over 48 h using an in vitro blood circulation (Chandler Loop). Radial and longitudinal dose distributions of a radiolabeled stent were obtained with a plastic scintillator dosimetry system. RESULTS: Stents with a length of 30 mm and a diameter of 8 mm were labeled with up to 33 MBq 188Re. A total of 69+/-4% of the labeled 188Re remained stable on the stent surface after 48 h. Ninety-five percent of the infinitely accumulated dose was supplied to the target tissue within 72 h. Including correction for radioactivity washout from the stent, the infinitely accumulated dose at 1 mm radial distance from the stent surface was 1.85+/-0.19 Gy/MBq 188Re/cm stent length. CONCLUSIONS: We developed a technique for radiolabeling of self-expanding nitinol stents with 188Re by dip coating and formation of 188Re chelate complexes. We provide dosimetry data useful for application of this beta-emitting stent for endovascular brachytherapy in peripheral vascular occlusive disease.

Brachytherapy↗
PubMed1996

Graether pupil expander for managing the small pupil during surgery.

The Graether pupil expander, a device for mechanically dilating the pupil, is a soft silicone ring grooved to engage the iris sphincter and maintain pupil dilation during cataract surgery and intraocular lens implantation. The ring is incomplete; the gap is bridged by a slender strap that provides access to the pupil aperture. The pupil expander will be preloaded on a disposable insertion tool that permits the expander to be inserted through the primary surgical incision. Stretching the pupil and placing the pupil expander is facilitated by an iris glide-retractor that fixates the iris sphincter at the incision prior to insertion of the pupil expander. Clinical experience with over 100 cases is briefly discussed.

Cataract Extraction↗
PubMed2006

Use of a biodegradable patch for reconstruction of large thoracic cage defects in growing children.

BACKGROUND/PURPOSE: At our institution, procedures were developed to enlarge and stabilize the thoracic cavity of children born with severe-enough abnormalities of the thoracic cage as to result in lack of normal lung growth and function. In addition to the device known as the vertical expandable prosthetic titanium rib (VEPTR), some type of patch material was needed to cover large congenital defects of the chest cage owing to rib absence or to cover defects created because of the expansion process. Initially, synthetic material, polytetrafluorethylene (Gore-Tex, WL Gore and Associates, Flagstaff, Ariz) was used, but this proved itself to be restrictive over time and required removal. Thus, a nonsynthetic biodegradable patch material was adopted for coverage of the defects (Surgisis, Cook, Bloomington, Ind). METHODS: From October 2001 through October 2004, 26 growing children undergoing thoracic cage reconstruction received the biodegradable extracellular matrix patch derived from porcine SIS (Cook). A patch was deemed necessary if any one of the following conditions was obtained: (a) herniation of the lung was likely; (b) chest wall musculature was significantly diminished; (c) injury to the lung was likely at reoperation; (d) the defect was greater than 2 x 2 cm. RESULTS: During the follow-up period, 41 months thus far, each of the 26 children has undergone routine, scheduled expansions or change-out procedures every 6 months. The SIS has not required removal for any reason and has not restricted growth of the thoracic cage. CONCLUSIONS: Compared with synthetic soft tissue patch material, the nonsynthetic, biodegradable soft tissue patch (SIS) has proven to be a superior alternative, thus far, to others for use in our population of patients for reconstruction of the thoracic cage in the growing child.

Absorbable Implants↗
PubMed1996

Closure of wounds in the upper extremity using a skin stretching device.

A skin stretching device (SSD) harnessing the viscoelastic properties of skin using incremental traction has been used in 20 patients with skin deficits in the upper extremity. Complications were few considering the extensive damage to the skin and included slight partial dehiscence, necrosis of skin edges, local infection and hypertrophic scars. All wounds healed without the need for further surgical procedures. Application of the SSD is simple and it can even be used at the bedside under local anaesthesia. It reduces the need for more complicated surgical procedures like grafts or flaps.

Adult↗
PubMed1996

Determining the safety of the silicone envelope: in search of a silicone antibody.

In the controversy surrounding breast implants, one of the crucial questions is whether patients ca form antibodies directed against the silicone shell of the implant. If this were the case, implications for current breast implant development, indeed, for all silicone medical devices, are far-reaching. To evaluate this hypothesis, sera from 18 patients who had tissue expanders and 15 control patients who had no silicone implant exposure were tested retrospectively for antibodies to the silicone using an enzyme-linked immunosorbent assay previously documented as a case report in the literature. Contrary to previous studies, no significant difference in antibody levels was found between test subjects and the controls. Additionally, this enzyme-linked immunosorbent assay for silicone antibodies was poorly reproducible. This study calls into question the existence of specific antibodies to the silicone shell. It also provides further data that the enzyme-linked immunosorbent assay may not be reliable as a silicone antibody test.

Antibodies↗
PubMed1992

Three decades of antiarrhythmic therapy.

Over the last several decades there has been an impressive expansion in the study and management of cardiac arrhythmias. New developments in diagnostic and interventional clinical electrophysiology as well as research at the cellular tissue and whole heart levels have improved our understanding of the mechanisms of arrhythmias and have allowed the development of new and effective treatment modalities. During the 1960s (Early Decade-Enabling) the first lifesaving measures such as cardiac resuscitation, external defibrillation, and temporary pacing were introduced in the new coronary care units. Cardiac catheterization and reproducible techniques for recording of intracardiac potentials were developed. The decade of 1970 to 1980 (Middle Decade-Diagnosis) was characterized by the development of programmed stimulation for initiation and termination of arrhythmias. This represented a real revolution in clinical cardiology that led to the understanding of the nature of several tachyarrhythmias and related them to experimental mechanisms of arrhythmogenesis. In the same decade, two other diagnostic tools emerged for assessing cardiac arrhythmias and monitoring the efficacy of antiarrhythmic drug therapy: ambulatory ECG monitoring and exercise testing. In addition, the impact of antiarrhythmic drugs on ionic currents was studied and drug classifications based on these properties appeared. The decade 1980-1990 (Recent Decade-Therapy), witnessed the development of interventional electrophysiology techniques such as transcatheter ablation, and the use of cardiac surgery for the ablation of arrhythmogenic substrates. Another major advance was the design of implantable devices capable of recognizing tachyarrhythmias and treating them by programmed stimulation or defibrillation shocks. In parallel, the efficacy and safety of antiarrhythmic drugs has been reassessed and new compounds are being developed.(ABSTRACT TRUNCATED AT 250 WORDS)

Anti-Arrhythmia Agents↗