Search PubMed⌕ Search

Biomedical subjects

H Weinberg

Publications and source records attributed to H Weinberg.

At least 73 records · Page 4Linked to original sources
PubMed1991

Latissimus dorsi musculocutaneous flap for elbow extension.

The latissimus dorsi mycocutaneous flap has developed a reputation for its versatility in both skin and soft tissue coverage and for restoration of elbow function in both flexion and extension. In a case presented, a large extra-abdominal desmoid was removed along with the entire deltoid and three-quarters of the triceps. The latissimus dorsi was elevated with a large overlying skin island and rotated on its neurovascular pedicle into the defect in the posterior shoulder and upper arm to replace the resected triceps and deltoid muscle, and to provide coverage in this region.

Back↗
PubMed1991

The use of a new perfusate in experimental microvascular flaps: a threefold increase in ischemic tolerance.

The benefit of perfusion washout in both experimental and clinical skin flaps has long been debated. By perfusing ischemic rat pedicled flaps with UW solution, a recently developed, high-molecular-weight, organ-preservation medium, a 170 percent increase in the critical ischemia time of treated versus untreated control flaps was demonstrated. Sixty rats were used in this study. A 3- x 6-cm unilateral abdominal skin flap based on the superficial inferior epigastric artery and vein was raised. The flaps were divided into three groups: Group 1 (control--no perfusion washout (n = 15); Group 2 (LR)--perfusion washout with lactated Ringer's solution (n = 15); Group 3 (UW)--perfusion washout with UW solution (n = 30). Flaps were subjected to varying periods of ischemia, ranging between 8 and 30 hr. The primary ischemia time at which 50 percent of the flaps survived clinically was 10 hr for Group 1, 15 hr for Group 2, and 27 hr for Group 3. The differences between the survival rates for flaps in Groups 1, 2, and 3 were statistically significant (p less than .0005). By bathing the vascular and parenchymal cells in an impermeant preservation solution, it was hypothesized that cellular swelling would be inhibited, thereby significantly improving a skin flap's tolerance to warm ischemia. Furthermore, after reviewing the pertinent literature, it is evident that the primary critical ischemia time of 27 hr is the highest reported to date for the normothermic experimental rat pedicled flap. Clinical application of these findings, as well as the need for further studies, are discussed.

Abdomen↗
PubMed1991

The internal oblique-iliac crest free flap in composite defects of the oral cavity involving bone, skin, and mucosa.

The reconstruction of oromandibular defects following ablative surgery is a challenging undertaking. When the defect involves skin as well as mucosa, the challenge becomes even greater. The internal oblique iliac crest osteomyocutaneous free flap is particularly useful for reconstruction of through-and-through composite defects due to the inclusion of two separate soft-tissue flaps on the same vascular pedicle. We report our experience with this flap in the reconstruction of 10 patients with such defects. The utility, and the limitations of this form of reconstruction are discussed in detail.

Aged↗
PubMed1991

Functional evaluation following microvascular oromandibular reconstruction of the oral cancer patient: a comparative study of reconstructed and nonreconstructed patients.

Over the past decade, the use of free flap transfers in head and neck surgery has led to remarkable advances in the reliability and the ultimate results of oromandibular reconstruction. Stable and retentive dental restorations have been achieved using enosseous implants placed directly into the vascularized bone flaps. However, the functional assessment of patients who underwent primary mandibular reconstruction with these techniques has not been previously reported. A group of 10 reconstructed and 10 nonreconstructed segmental hemimandibulectomy patients were compared using a battery of tests to assess their overall well-being, cosmesis, deglutition, oral competence, speech, length of hospitalization, and dental rehabilitation. In addition, objective measures of the masticatory apparatus (interincisal opening, bite force, chewing performance, and chewing stroke) were used to compare these two groups as well as normal healthy subjects and edentulous patients restored with conventional and implant-borne dentures. The results show a clear advantage for the reconstructed patients in almost all categories. Persistent problems and future directions in oromandibular reconstruction are discussed.

Adult↗
PubMed1991

Imaging techniques in the localization of epileptiform abnormalities.

The success of surgical intervention in the partial epilepsies is crucially affected by the accuracy of pre- and intraoperative source location techniques. Several approaches to the localization problem have been employed, that with the longest history being scalp-recorded EEG. Despite considerable advances in other imaging technologies such as MRI and PET, localization via the electrical signals generated by epileptic brain continues to provide the data most relied upon in pre-operative assessment. The present paper presents an overview of the contribution of various localization techniques. It is argued that electrical signals of the brain, as represented by EEG and MEG, remain the best methods to locate sources, and that the application of analysis techniques presently under investigation will further improve the accuracy of the non-invasive scalp-EEG approach.

Electroencephalography↗
PubMed1991

Abortion attitudes.

Explore the source record for details and available documents.

Abortion, Induced↗
PubMed1990

Use of multiple dipole analysis for the classification of benign rolandic epilepsy.

The clinical literature has suggested that while the clinical features and presentation of benign rolandic epilepsy in children (BREC) are known, the neuronal mechanism of the epileptic focus is poorly understood. Classification of clinical subtypes is usually made by determining whether there are supplementary clinical signs of brain damage, in which case the epilepsy is classified as non-benign or "atypical". Studies of EEG findings in BREC have suggested that the source of the epilepsy is in the Rolandic fissure. We investigated dipole source modelling in 24 children, comparing the results of one and two dipole models. The results indicate that atypical BREC patients have a more complex distribution of dipoles and that single dipole fits may be more predictive of typical BREC than multiple dipole fits. The implications of these results are discussed.

Brain Mapping↗
PubMed1990

Asthma in primary care patients. Challenges and controversies.

Asthma varies in intensity, and patients must be treated as individuals to whom formulas do not apply. Often, the most difficult person to treat is the first-time patient whose clinical course is unknown and whose response to medications is totally untested. Although exacerbating substances should be avoided whenever possible, medication unfortunately is still needed by most asthmatic patients. At present, the choice of initial medication is subject to individual physician preference; beta 2-adrenergic agonists, cromolyn sodium (Intal), theophylline, and aerosol corticosteroids are all acceptable as first-line treatment. Addition of a second, third, or fourth medication again depends on individual response and physician choice. Patients with asthma need to be educated regarding the nature of the disease and its almost total unpredictability. Equally important is a frequent review of medications and a willingness to alter regimens as situations require.

Adrenal Cortex Hormones↗
PubMed1990

The neurofasciocutaneous radial forearm flap in head and neck reconstruction: a preliminary report.

The radial forearm free flap has achieved considerable popularity as a reconstructive technique due to its thin, pliable tissue and long vascular pedicle. The successful use of this flap as a carrier of a vascularized nerve to bridge motor nerve gaps and as a sensate flap has not been previously reported in head and neck reconstruction. The superficial branch of the radial nerve was used as a vascularized nerve graft to bridge a facial nerve defect following radical parotidectomy. The medial and lateral antebrachial cutaneous nerves were used to re-establish sensation in a reconstructed pharyngeal mucosal defect. The published clinical and experimental studies on vascularized nerves and sensate flaps are reviewed in detail.

Adolescent↗
PubMed1990

Electroencephalographic and magnetoencephalographic studies of motor function.

Although a great deal has been learned from the study of scalp-recorded movement-related potentials, the exact origin of the various components described above remains unclear, mainly because of the limited spatial resolution of the EEG and the consequent difficulty in predicting sources from the surface distribution of these components. The introduction of the MEG and source localization methods based on neuromagnetic recordings has provided a new means by which to study the cortical activation during movement in humans. The study of movement-related magnetic fields of the brain is still at an early stage of development. However, the data reviewed to date indicate that the MEG offers a promising means by which to study (noninvasively) cortical motor function. With regard to the data reviewed here, the following conclusions can be made: 1. Slow "readiness" magnetic fields can be recorded prior to a variety of voluntary movements and display a topography which indicates the activation of bilateral sources, even if the instructed movement is unilateral. Sources in the contralateral hemisphere appear as early as 0.5 sec before the movement and appear to be localized in the sensorimotor cortex. Consequently, the assumption of a contralateral source being the only or primary generator of the readiness potential, based on EEG data, must be tempered. 2. A large-amplitude "movement-evoked field" (occurring at a post-EMG-onset latency of about 110 msec for finger movements) is probably the counterpart of the MP and appears to be the result of a dipolar source localized to the contralateral sensorimotor area. This source is probably the first sign of movement reafferent input to cortex. 3. Variability in the movement-evoked field across individuals, which are much more evident in MEG than in EEG, may reflect the summation of multiple sources active in the region of the sensorimotor cortex during movement onset (i.e., both pre- and postcentral generators). In some instances, it may be possible to extract simpler elements of these complex sources based on assumptions of temporal overlapping of pre-movement and movement-evoked activity.

Brain Mapping↗
PubMed1989

The internal oblique-iliac crest osseomyocutaneous free flap in oromandibular reconstruction. Report of 20 cases.

Microvascular free tissue transfer techniques using composite flaps are the most reliable method for the combined bone and soft-tissue reconstitution of oromandibular defects. Functional oromandibular reconstruction requires that maximum tongue mobility be achieved along with dental prosthetic rehabilitation. The internal oblique-iliac crest osseomyocutaneous microvascular free flap was used in 20 patients for oromandibular reconstruction. The internal oblique muscle, based on the ascending branches of the deep circumflex iliac artery and vein, was used to resurface mucosal defects of the oral cavity and pharynx. The iliac bone, because of its length, width, and natural contour, is the best source of vascularized bone for mandibular reconstruction. The improved soft-tissue component of this composite flap markedly improved the functional results. Reconstruction failed in one patient. Eleven patients underwent dental rehabilitation with either a tissue-borne or osseointegrated implant-borne denture. Follow-up of longer than one year showed minimal donor site morbidity.

Adult↗
PubMed1989

Geometry of the vascular pedicle in free tissue transfers to the head and neck.

Traditionally, the most important parameters for success in free tissue transfer have been expertise in performing small vessel anastomoses, meticulous donor site dissection, and careful recipient vessel preparation. It has been our experience, in free flap transfers for head and neck reconstruction, that a very crucial, often unrecognized, parameter is the geometry of the vascular pedicle. This term encompasses the three-dimensional positioning of the nutrient vascular pedicle as well as vessel tension and redundancy. The ideal axis for the lie of the vascular pedicle in the neck is in the longitudinal direction. This configuration helps to eliminate the kinking of the pedicle that is observed with side-to-side movements of the head. The primary objectives in recipient vessel selection are to use a healthy artery and vein and to perform the anastomoses in a location that provides easy access for the surgeon and assistant. Recipient vessel selection is also a major determining factor in the achievement of the desired pedicle geometry. We believe that the transverse cervical artery and the external jugular vein are the best recipient vessels for free tissue transfer. The reasons for this selection, as well as technical details to improve pedicle geometry, are discussed in depth. Representative cases that demonstrate pitfalls in vascular pedicle geometry are presented.

Adult↗
PubMed1989

Free flap design in head and neck reconstruction to achieve an external segment for monitoring.

Postoperative monitoring of the perfusion of a free flap used in head and neck reconstruction is vitally important in achieving a favorable outcome. There are a wide range of methods that have been advocated to assist in this surveillance. However, at this time, there is no one technique that is universally efficacious in detecting early arterial and venous occlusion. In our experience, the most reliable means of monitoring has been the clinical assessment of flap color, capillary refill, tissue turgor, and bleeding. To assess these parameters, a portion of the flap must be accessible for observation. When the defect is buried, as is often the case in head and neck reconstruction, flap design is critical to achieve a reliable external segment for monitoring. The methods for exteriorizing a well-vascularized portion of tissue in the most commonly used flaps are described.

Gastric Mucosa↗
PubMed1989

Neuromagnetic fields accompanying unilateral finger movements: pre-movement and movement-evoked fields.

Neuromagnetic fields accompanying voluntary flexions of the right index finger were studied in five subjects. In all subjects, slow magnetic fields were observed over the central scalp beginning about 1 second prior to movement onset. These fields displayed a similar time course to the electrically recorded "readiness potential", but with reversals of field direction over regions of the rolandic fissure over both hemispheres. Least-squares fitting of two current dipole sources for the pre-movement fields resulted in a consistent localization of one source in the region of the rolandic fissure contralateral to the side of movement in four subjects. Ipsilateral dipole sources fitted inconsistently at deeper locations or outside the head indicating the inability of a single dipole source to account for the ipsilateral fields. A large field reversal was also observed over the contralateral (left) hemisphere, 90-130 ms after onset of EMG activity in the active muscles. In some subjects, single dipole sources could be fitted to this "movement-evoked" field at locations slightly deeper and posterior to the pre-movement source locations in the contralateral hemisphere, possibly indicating unilateral activation of somatosensory cortex related to sensory feedback during the onset of this movement. Subtraction of pre-movement field activity from post-movement fields improved the ability to fit a single contralateral rolandic source for all subjects suggesting that pre-movement sources continue to be active during movement onset. These findings confirm previous reports that voluntary finger movements are preceded by slow magnetic fields.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

Functional mandibular reconstruction of patients with oral cancer.

For the patient with oral cancer who has undergone quadrant resection, mandibular reconstruction provides normalization of the lower facial contour, regained architectural support, and reestablishment of occlusal relationships. Reconstruction with vascularized bone offers the most rapid rehabilitation. Replacement of dentition provides improved deglutition, mastication, and speech. In eligible patients the use of osteointegrated implants can provide rigid stabilization for dental prostheses. In previous studies these implants were placed in a secondary procedure. In the present study microvascular mandibular reconstruction was combined with primary placement of osteointegrated implants in the treatment of seven patients. Preliminary results indicate that the combination of procedures can provide more rapid and effective rehabilitation for the patient with cancer. Issues for further study are also identified.

Adult↗
PubMed1989

Perfusion washout: increasing a microvascular free flap tolerance to ischemia.

Thirty-five Sprague-Dawley rats were divided into control (non-exsanguinated) groups of 8 and 10 hr of ischemia, and exsanguinated groups of 8, 10, 14, 16, and 18 hr of ischemia. Free flaps based on the superficial inferior epigastric artery were anastomosed to the contralateral femoral vessels after their designated ischemia period. Reperfusion was assessed by measuring fluorescein uptake in the free flaps after clamp release. In the exsanguinated groups, 100 percent (5/5) of the 8-hr, 10-hr, and 14-hr ischemia groups survived; 80 percent (4/5) of the 16-hr ischemia group free flaps survived; and none (0/5) of the 18-hr ischemia flaps survived. In the control groups, 100 percent (5/5) of the 8-hr ischemia flaps survived, while none (0/5) of the control 10-hr ischemia flaps survived. Fluorescein uptake correlated well with flap survival. By exsanguinating an experimental microvascular free flap prior to its ischemia period, it is possible to dramatically increase flap tolerance to ischemia.

Animals↗
PubMed1989

The internal oblique-iliac crest osseomyocutaneous microvascular free flap in head and neck reconstruction.

The iliac crest osseocutaneous free flap, based on the deep circumflex iliac artery and vein, was a landmark contribution to head and neck reconstruction. Two major problems associated with this flap are the lack of flexibility in placement of the skin paddle with relation to the bone graft, and the excessive thickness of the skin paddle when used in the oral cavity. The scapular osseocutaneous flap has achieved recent popularity for mandibular reconstruction based, in part, on its thin skin paddle that is easily positioned in three dimensions with relation to the bone graft. However, the segment of bone that can be harvested from the iliac crest is superior to that of the lateral border of the scapula because of its increased length, thickness, and natural contour. In 1984 the internal oblique free muscle flap based on the ascending branch of the deep circumflex iliac artery was described for use in reconstruction of the extremities only. The authors introduce the application of the internal oblique-iliac crest osseomyocutaneous free flap for mandibular reconstruction. The mobility of the internal oblique muscle with relation to the iliac bone graft has permitted its use for inner mucosal defects or outer cutaneous defects when covered with a skin graft. Following denervation atrophy, the muscle component becomes a thin, pliable piece of tissue that easily conforms to three-dimensional defects of the head and neck. This increased flexibility, the established benefits of the iliac bone, and the ease of intraoperative positioning for a two-team approach make this composite flap an outstanding tool for mandibular reconstruction. Two representative cases and a detailed description of flap harvesting, insetting, and donor-site closure are presented.

Carcinoma, Squamous Cell↗