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Biomedical subjects

Y Har-Shai

Publications and source records attributed to Y Har-Shai.

At least 55 records · Page 3Linked to original sources
PubMed1993

Chordee: different concept and new trend of treatment.

Chordee or ventral curvature of the penis is commonly associated with and occasionally without hypospadias. The usual recommended treatment is excision of the fibrous tissue that is responsible for the bowing. This results in a proximal retraction of the meatus. With a different concept and explanation of the ventral curvature, we treat this abnormal condition as a shortage of tissue. More than a hundred consecutive cases of chordee with and without hypospadias were treated by skin release and dorsal to ventral transposition of preputial skin as well as hypospadias repair. The whole procedure is simple, planned as a single-stage operation with less morbidity or fewer complications. The meatus is not pushed back proximally, no dissection distal to the meatus is performed, and there is no need for tissue excision. The results were very successful, with no recurrence of the ventral curvature.

Follow-Up Studies↗
PubMed1992

The viability of revascularized calvarial bone graft in a pig model.

This study compared the vascularity and resorption of calvarial bone flaps based on an undisturbed pedicle and on a previously (4 weeks) detached pedicle of the superficial fascia (galea) and periosteum and free calvarial bone grafts. Nine adult pigs were used, in three of which a silicone rubber compound was injected intravascularly immediately after the transfer confirmed the vascularity of both pedicled bone flaps. In six pigs, volume changes were assessed intraoperatively by a water displacement method and also 12 weeks postoperatively. Both pedicled bone flaps preserved their original volume, whereas free skull grafts showed approximately 50% of volume loss (p less than 0.001). Decalcified hematoxylin and eosin sections of the specimens obtained 12 weeks postoperatively showed a normal calvarial appearance in both pedicled bone flaps and extensive fibrous tissue infiltration into free grafts. It is suggested that a previous detachment of galea and periosteum does not interfere with the use of vascularized calvarial bone graft, which may provide a more predictable result than a free bone graft.

Animals↗
PubMed1992

Comparison of inorganic bovine bone mineral particles with porous hydroxyapatite granules and cranial bone dust in the reconstruction of full-thickness skull defect.

Twenty adult rabbits were used to evaluate the biocompatibility and osteoconductivity of Bio-Oss, an inorganic bovine bone mineral, in the reconstruction of full-thickness skull defects. Skull defects were treated with either autogenous bone dust, porous hydroxyapatite granules, Bio-Oss particles, or were left untreated as controls. Histological examination of decalcified sections showed incorporation of Bio-Oss into the host tissue without a significant inflammatory reaction. Measurement of the profile area occupied by the bone revealed that Bio-Oss, hydroxyapatite, and the control had the same amount of bone ingrowth, whereas autogenous bone dust produced a greater amount of bone (p < 0.01). We conclude that Bio-Oss, like porous hydroxyapatite, has sufficient osteoconductive properties and can also be used as a bone substitute material.

Animals↗
PubMed1992

Muscle microcirculatory impairment following acute compartment syndrome in the dog.

Visualization of the intramuscular microcirculation during and after compartmental syndrome was studied by microangiograms and histologic cross sections. A marked reduction in the circulation of the endomysial capillary network was found during compartment tamponade, whereas the perimysium arteriolar system was patent. Revascularization took place by formation of distorted blood vessels accompanied by intramuscular hematomas in muscles 7 and 14 days after the compartment insult. The cross sections show massive fibroblastic activity around blood vessels that caused concealed intramuscular pressure-ischemic contracture resulting in the foci of myofibrillar necrosis seen within normal muscle tissue. The muscle located in the tamponaded compartment profusely bleeds when it is touched, even though its viability is in doubt. The explanation for this clinical observation might be the abnormal intramuscular revascularization that was found in this work.

Acute Disease↗
PubMed1992

The vascular anatomy of the galeal flap in the interparietal and midline regions.

The potential extension of the galeal flap in the interparietal area was studied on 17 fresh human cadaver heads by intravascular dye injection technique. It was demonstrated that an ipsilateral superficial temporal artery that supplies the galeal flap does not cross the midline or anastomose with the contralateral superficial temporal artery but ensures the survival of a flap extended up to 1 cm proximal to the sagittal suture line. The width of the temporoparietal flap can be extended up to 15 cm, depending on the vascular pattern of the superficial temporal artery. When required, the lateral extension may provide the required soft-tissue bulk despite the reduced flap length.

Aged↗
PubMed1991

Hypertonic mannitol ameliorates intracompartmental tamponade in model compartment syndrome in the dog.

Acute compartment syndrome (ACS) is a devastating complication of rhabdomyolysis caused by muscle tamponade secondary to increased intracompartmental pressure (Pi). ACS requires emergency surgical decompression when Pi greater than 30 mmHg (normal less than 4.0 mmHg) and clinical signs exist. The present study was undertaken to examine whether mannitol which has been used extensively for prevention of acute renal failure in rhabdomyiolysis may also improve muscular hemodynamics in ACS. ACS was produced in dogs by injecting dog plasma into the anterolateral compartment of the hind limb. The Pi was directly monitored. Control dogs received saline, whereas experimental dogs received intravenously 20% mannitol (0.15 ml/min/kg) over a period of 1 h. The initial Pi was set arbitrarily at 100 mm Hg. Following the establishment of ACS, the spontaneous mean decrease in Pi in the control group was 40% of initial value over 60 min (n = 5) versus a decrease of 65%/60 min in the experimental (mannitol) group (n = 7, p less than 0.01). The net mean decompressive effect of mannitol treatments was approximately 28 mm Hg (mean control Pi minus mean experimental Pi at time 60 min). Extrapolated to man with ACS, such a decrease in Pi induced by mannitol theoretically could relieve compartmental tamponade noninvasively.

Angiography↗
PubMed1990

The management of exposed cardiac pacemaker pulse generator and electrode using restricted local surgical interventions; subcapsular relocation and vertical-to-horizontal bow transposition techniques.

This paper describes an approach to the treatment of exposed pacemaker generator and electrode. Local infection is controlled by the administration of systemic antibiotics and topical antibacterial solutions. Because the generator and lead are enveloped by an inert synthetic coating, it is possible to eradicate an infection without their removal if it is due to a weak opportunist pathogen fully sensitive to antibiotics. Thereafter, subcapsular relocation of the exposed generator or vertical-to-horizontal transposition of the exteriorised lead is carried out. These surgical interventions are designed to overcome the vertical force which tends to cause the extrusion of the pacing hardware.

Aged↗
PubMed1989

Free-fat injections for the correction of hemifacial atrophy.

Three adult patients with long-standing hemifacial atrophy were treated with repeated free-fat injections at 4- to 8-week intervals. The longest follow-up study to date is 18 months, and following the expected postoperative resorption, no further loss of bulk of injected fat has been observed. On palpation, the feel of the fat is normal, and facial expression is also good. The relative ease of this procedure, which does not entail any scarring, appears to justify more widespread use of free-fat injections to restore facial soft-tissue depressions.

Adipose Tissue↗
PubMed1988

External longitudinal splitting of the biceps brachii muscle for coverage of repaired brachial vessels: an anatomical study and clinical application.

The external longitudinal splitting of the biceps brachii muscle offers a convenient and safe method for covering exposed vessels in the medial aspect of the arm in cases with loss of soft tissue. This anatomical study reveals rather variable and inconsistent patterns of blood supply to the biceps brachii muscle. The common denominator among the patterns is the fact that the nutrient vessels to the muscle originate in its posterior deep surface and course thereafter in a fan shape upward to the surface of the anterior aspect of the muscle. This microcirculatory pattern permits the external longitudinal splitting of the biceps brachii muscle along the whole anteromedial aspect of the short-headed belly without compromising its blood supply and function. An illustrative case is described.

Adult↗
PubMed1987

External longitudinal splitting of the tibialis anterior muscle for coverage of compound fractures of the middle third of the tibia.

In this modern era, compound fractures of the middle third of the tibia are relatively common. With the advent of external fixation, these fractures can be more rapidly and effectively dealt with, and attention can be directed to immediate coverage of the exposed bone. External longitudinal splitting of the anterior tibialis muscle offers a convenient and safe method for converting the open fracture to a closed one. The uniqueness of the tibialis anterior muscle is two-fold. It is circumpennate, and it has an internal axial tendon corresponding to almost its total length. Both these features impart to it considerable strength, and the muscle splitting herewith described does not appear to impair its function. Five treated limbs, each with loss of soft tissues overlying compound mid-third tibial fractures, are presented. Rapid healing and virtual absence of bone infection was observed in all cases.

Adult↗
PubMed1984

Blood supply and innervation of the supermedial thigh flap employed in one-stage reconstruction of the scrotum and vulva--an anatomical study.

The supermedial thigh flap is an arterial and sensate flap. Anatomical studies reveal both large and small nutrient arteries. Its largest and most consistent artery is the superficial branch of the deep external pudendal artery, which constitutes the main circulation. The secondary blood supply to the base of the flaps is contributed by musculocutaneous perforators of the medial circumflex femoral artery. Subcutaneous branches of the superficial femoral artery, when present, are an additional source of arterial supply. Branches of the ilioinguinal nerve provide sensory innervation to the flaps.

Arteries↗
PubMedDate not supplied

Large liponecrotic pseudocyst formation following cheek augmentation by fat injection.

A case in which a growing cystic mass developed in the submandibular area, 6 months following fat injection to the cheek and mandibular area, is described. Histological examination revealed a liponecrotic pseudocyst. It is suggested that subcutaneous masses appearing in an area, which was previously injected with fat, should be excised. Diagnostic aspiration procedures may cause leakage of its oily content and possible further granulomatotic reactions and cysts.

Adipose Tissue↗
PubMedDate not supplied

Viscoelastic properties of the superficial musculoaponeurotic system (SMAS): a microscopic and mechanical study.

A study was undertaken to determine the physical properties and microscopic structure of the superficial musculoaponeurotic system (SMAS) tissue. Forty virginal specimens and eight reoperated specimens were examined. The following findings were discovered. 1) Microscopic appearance shows the SMAS to consist of collagen fibers, a relatively high concentration of elastic fibers interspersed with fat cells. 2) On scanning electron microscopy, the virginal SMAS shows the collagen fibers to have a similar convoluted appearance as in the dermis. There is some evidence of parallelization of the collagen fibers in the reexcised SMAS specimens. 3) Mechanical testing (Instron) demonstrates that both the SMAS and preauricular skin were subjected to a series of loading/ unloading tests at various rates, amplitudes, and stress relaxation tests. Both sets of specimens indicated definite viscoelastic properties. Although the mechanical behavior of both tissues was somewhat similar, the viscoelastic effect of the SMAS was less pronounced. A slackening effect of the SMAS indicated a gradual expansion of the SMAS postoperatively. These results could provide some indication of the long-term effects of SMAS surgery.

Collagen↗
PubMedDate not supplied

The volume limitation of the galeal temporalis flap in facial augmentation.

Galeal temporalis flaps based on the superficial temporal vessels have been used for facial augmentation and can be extended to the contralateral side beyond the midline in order to achieve maximum volume. In five patients, the volumes of extended galeal flaps were measured intraoperatively using a water displacement method. The calculated volume varied between 28 and 38 cm3. Experience with this flap showed satisfactory results with no complications; therefore, it is concluded that the extended galeal temporalis flap may be a first choice in the correction of facial soft tissue deficits less than 40 cm3. Clinical cases are presented.

Adult↗