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Biomedical subjects

H Weinberg

Publications and source records attributed to H Weinberg.

At least 55 records · Page 3Linked to original sources
PubMed1994

Microvascular free flaps in head and neck reconstruction. Report of 200 cases and review of complications.

OBJECTIVE: Microvascular free-tissue transfer to the head and neck has become an accepted method of reconstruction owing to increased success rates and superior aesthetic and functional results. Although the large number of arteries and veins in the neck make free-flap revascularization easier than in other recipient sites of the body, there are also unique problems that pose significant risks to the success of the procedure. We report our experience with 200 microvascular free flaps performed between 1987 and 1992. SETTING: This study was conducted at a tertiary referral center. PATIENTS: The majority of patients in this series underwent surgery for squamous cell cancer. Approximately 75% of the reconstructions were performed for defects of the oral cavity. There were 120 vascularized bone-containing free flaps for mandibular and midface reconstruction. The remaining 80 soft-tissue flaps were used for a variety of defects ranging from the scalp to the pharyngoesophagus. RESULTS: An overall success rate of 93.5% for free-tissue transfers is reported. Greater experience with this technique has resulted in a reduction and a change in the nature of the complications encountered compared with those seen in the early part of our series. Donor and recipient site complications, including flap failures and anastomotic revisions, are analyzed in detail with respect to age, radiation status, donor site, and whether the ablative procedure was done for a primary or recurrent neoplasm.

Adolescent↗
PubMed1994

Substance use among the mentally ill: prevalence, reasons for use, and effects on illness.

Substance use among a random sample of mentally ill, community-based patients was examined. Current use was found to have declined substantially from a high lifetime prevalence, and a family history of substance abuse was associated with moderate to heavy use. No association was found between heavy substance use and elevated psychopathology, hospitalization, or medication noncompliance. Hospital admissions and some symptoms were less prevalent among users preferring marijuana.

Adolescent↗
PubMed1994

Use of urokinase during secondary ischemia in experimental skin flaps.

The ability of urokinase to salvage experimental flaps after a secondary ischemic insult was investigated in a rat model. Unilateral abdominal island skin flaps based on the superficial inferior epigastric vessels were raised and subjected to either 4 or 6 hours of primary ischemia followed by 12 hours of reperfusion and varying lengths of secondary ischemia. At the conclusion of secondary ischemia, the flaps were perfused with either lactated Ringer's solution or urokinase. One group of flaps served as a control and received no postischemic perfusion washout. The secondary critical ischemia time at which 50% of the flaps failed clinically was greater for flaps perfused with urokinase. Furthermore, the survival rates for all flaps perfused with urokinase were significantly greater than either control flaps or flaps perfused with lactated Ringer's solution (p < 0.05). Flap survival decreased significantly in all groups with increasing primary and/or secondary ischemia time (p < 0.05).

Animals↗
PubMed1994

Iloprost improves survival of ischemic experimental skin flaps.

The ability of the prostacyclin analogue iloprost to improve survival of ischemic experimental skin flaps was investigated. Unilateral island skin flaps based on the superficial inferior epigastric vessels were raised in 70 rats and subjected to varying lengths of primary ischemia. The flaps were divided into the following four groups: group I, no perfusion washout; group II, postischemic washout with lactated Ringer's solution; group III, postischemic washout with urokinase; and group IV, postischemic washout with iloprost. Flap survival rates for group IV were significantly higher than all other groups (p < 0.05). The primary ischemia time at which 50% of the flaps failed was 8.9 hours for group I, 9.5 hours for group II, 13.3 hours for group III, and 15.3 hours for group IV. This is the first study to investigate the effect of iloprost on skin flap survival. Iloprost was found to be significantly more effective than urokinase in salvaging ischemic experimental skin flaps.

Animals↗
PubMed1993

UW solution as an experimental microvascular skin flap perfusate.

UW solution has been found to be an effective organ perfusate for transplantation. Initial studies in experimental pedicle skin flaps have also demonstrated its unique effectiveness in prolonged ischemia. To understand better the limits of its preservation properties without the influence of endothelial clamp damage, we have undertaken to study the properties of UW solution in experimental microvascular free flaps. Control, lactated Ringer's, and UW solutions were utilized in pedicle and microvascular free flaps in Sprague-Dawley rats over varying periods of ischemia. UW solution demonstrated a clear superiority over all other solutions in both flap models. In addition there also was a significant prolongation of critical ischemia time in UW-treated free flaps compared to pedicle flaps.

Adenosine↗
PubMed1993

The additive beneficial effect of UW solution and urokinase on experimental microvascular free-flap survival.

Pharmacologic manipulation of free flaps to enhance tolerance to ischemia has become a subject of great interest in the research literature. In an effort to improve survival, perfusion washout of experimental free flaps was performed following an episode of primary ischemia. The perfusates utilized were lactated Ringer's solution (LR), University of Wisconsin solution (UW), a high-molecular-weight medium used in organ preservation, and urokinase, a thrombolytic agent. Seventy-five rats were used in this study and divided into groups of 5 each. A 3 x 6-cm abdominal free flap based on the superficial inferior epigastric vessels was raised in each rat. The free flaps were subjected to either 12 or 18 hr of primary ischemia. Following the period of ischemia, perfusion washout was performed with either LR, UW solution, or urokinase at increasing concentrations alone or in combination with UW solution. Urokinase was first evaluated as a perfusate alone at increasing concentrations. In the 12-hr ischemia group, free-flap survival was shown to increase from 0 percent in the LR-perfused flaps to 20 percent, 60 percent, and 80 percent in flaps perfused with 12,500, 25,000, and 100,000 U of urokinase, respectively (p < 0.05). A similar increase in survival was demonstrated in the 18-hr ischemia group, where 0 percent, 20 percent, and 40 percent of flaps survived following perfusion with 12,500, 25,000, and 100,000 U of urokinase, respectively (p < 0.05). Urokinase was then perfused along with UW solution to evaluate the combined effect on flap survival.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine↗
PubMed1993

Enhancement of fluorescein perfusion in experimental skin flaps following postischemic washout with iloprost, urokinase, verapamil, and University of Wisconsin solution.

The enhancement of blood flow in experimental skin flaps following postischemic perfusion washout was investigated in rats. Unilateral island skin flaps based on the superficial epigastric vessels were raised and subjected to 6 hr of primary ischemia. Group 1 was designated as a control and did not undergo postischemic perfusion washout. In the remaining rats, postischemic washout was performed with one of five agents: Group 2--lactated Ringer's solution; Group 3--University of Wisconsin solution, an organ preservation medium; Group 4--verapamil, a calcium channel blocker; Group 5--urokinase, a thrombolytic agent; Group 6--iloprost, a stable prostacyclin analog. Two hours following perfusion washout, fluorometric analysis revealed a statistically significant enhancement of blood flow in Groups 4, 5, and 6, compared to Groups 2 and 3 (p < 0.05). Furthermore, a significant increase in skin surface fluorescence was demonstrated in all the flaps that underwent perfusion washout, compared to the control flaps (p < 0.05). By analyzing skin surface fluorescence, the enhancement of nutritive blood flow in flaps, following postischemic perfusion washout, was evaluated. This is the first study in which the above pharmacologic agents were compared in a quantitative manner.

Adenosine↗
PubMed1993

The role of microvascular surgery in limb-sparing procedures for malignant tumors of the knee.

Limb-sparing surgery has proven to be a feasible alternative to amputation for treatment of malignant tumors about the knee. Microvascular surgery and the possibility of providing healthy, stable soft-tissue coverage to the affected limb have expanded the possible role of limb-sparing techniques. Microvascular free flaps were utilized in 26 patients undergoing resection for large malignant tumors of the knee or adjacent to the knee. Patients were then followed for a minimum of 3 years to a maximum of 7 years and evaluated for tumor recurrence and limb function. Survival and disease-free interval were 68 and 77 percent, respectively, in stage II patients and only 50 and 0 percent, respectively, in stage III patients. Function, as determined by the MSTS functional evaluation system, was found to be fair to good in all patients. Microvascular free-tissue transfer has proven to be a valuable adjunct in limb-sparing surgery.

Adolescent↗
PubMed1993

Prolongation of secondary critical ischemia time of experimental skin flaps using UW solution as a normothermic perfusate.

A myriad of investigations have been published on the pharmacologic manipulation of flaps to enhance tolerance to ischemia. We recently reported a threefold increase in ischemic tolerance of the rat abdominal skin flap pedicle after 6 hours of primary ischemia and 12 hours of reperfusion. Flaps underwent normothermic perfusion washout with lactated Ringer's or U.W. solution, a newly developed organ preservation medium. Perfusion washouts were performed at one of three different points in the protocol: (1) onset of primary ischemia; (2) onset of secondary ischemia; or (3) 2 hours after onset of secondary ischemia. The last group was used to simulate the clinical situation in which flaps are discovered and salvage procedures instituted at a delayed time interval. This is the longest normothermic ischemic interval reported. We undertook the present study to determine the utility of the U.W solution in prolonging the tolerance of the flap to a second ischemic insult after a period of reperfusion. Seventy-five unilateral rat abdominal skin flaps were raised. Secondary ischemia was produced by placing a microvascular clamp across the inferior epigastric pedicle. Flap survival was assessed at 1 week postoperatively. While none of the nonperfused flaps survived 8 hours of secondary ischemia, at least 50% of the U.W. perfused flaps survived an average of 14 hours of secondary ischemia. Lactated Ringer's perfusion washout only modestly increased the ischemic tolerance. Perfusion washout in the secondary ischemic phase improved the ischemic tolerance to a significantly greater degree than in the primary ischemic interval.

Adenosine↗
PubMed1993

Hemodynamics of the rodent abdominal skin flap following primary ischemia.

The effect of varying periods of ischemia and reperfusion times on subsequent blood flow was studied in the rodent abdominal skin flap. Using perfusion fluorometry, measurements of blood flow were quantified in 60 Sprague-Dawley rats undergoing clamp-induced ischemic periods ranging from 0 to 6 hours and reperfusion times ranging from 2 to 8 hours. Flaps subjected to ischemia times of 0, 2, 4, or 6 hours require 8 hours of reperfusion time before reaching baseline levels of blood flow. Blood flow in flaps subjected to 6 hours of ischemia was statistically less than the flow in flaps ischemic for 0, 2, and 4 hours and was directly related to length of reperfusion. These results demonstrate that flap perfusion does not fully take place immediately after clamp release. The factors thought to be responsible for these findings and the implications for the design and interpretation of flap ischemia experiments are discussed.

Abdomen↗
PubMed1992

Chest wall resection for locally recurrent breast cancer: indications, technique, and results.

A series of 100 patients with locally advanced carcinoma of the breast was analyzed for chest wall recurrence alone after primary treatment. Five patients were found to have had chest wall recurrence alone and were treated with en bloc chest wall resection. This group of patients was analyzed for the pathophysiology of recurrence including characteristics of the primary tumor, location of the chest wall recurrence, and overall local salvage and survival after chest wall recurrence. In this series, local recurrence after radical chest wall resection was 20%. The incidence of systemic recurrence after chest wall resection was 60%. The mean survival for the entire group was 17 months after chest wall recurrence and radical resection. The main surgical objectives, including relief from painful, inflammatory, and bleeding complications, were achieved in all patients after chest wall resection. Although patients with isolated chest wall recurrence included a highly selected group, chest wall resection with myocutaneous reconstruction may provide long-term disease-free survival for these patients.

Aged↗
PubMed1992

Surface sensibility of the floor of the mouth and tongue in healthy controls and in radiated patients.

Increased areas of anesthesia in the oral cavity have been shown to significantly impair oral function in normal individuals. In patients who undergo oral cavity reconstruction, loss of sensation plays a major role in producing disturbances in postoperative oral function. Free tissue transfer techniques have permitted the problem of sensory loss to be addressed through the use of sensate cutaneous free flaps, in which microneural anastomoses are performed between a sensory nerve supplying the flap and a recipient nerve in the head and neck. To critically assess the results of such reconstructions, the effect of sensory restoration on oral cavity rehabilitation must be studied. As a first step toward this goal, normal values for sensory discrimination of the floor of mouth and tongue are needed. Previous studies of oral sensation failed to examine the ventral tongue and floor of mouth. The purpose of this study is to determine the surface sensibility of these regions in healthy patients and in patients who received radiation therapy to the oral cavity. Sensation was evaluated using static and moving two-point discrimination in 90 healthy subjects divided equally into three age groups: 20 to 40 years, 41 to 60 years, and 61 to 80 years. In addition, 20 patients who received radiation therapy were studied. The mucosa of the dorsal and ventral aspects of the lateral tongue, tongue tip, and floor of mouth was examined. The tongue tip is the most sensitive area, followed by the dorsal lateral tongue, ventral lateral tongue, and floor of mouth. The effects of age and radiation therapy on sensory discrimination are discussed.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

The combined sensate radical forearm and iliac crest free flaps for reconstruction of significant glossectomy-mandibulectomy defects.

The loss of motor and sensory function of the tongue following ablative surgery has a devastating effect on oral function. At the present time, there is no way to restore lost tongue musculature following partial glossectomy. The use of sensate cutaneous flaps has been shown to restore sensory feedback to reconstructed areas of the oral cavity. No single composite flap supplies a sensate soft-tissue component together with an osseous component of sufficient bone stock for functional mastication. In this article, the combination of the radial forearm free flap with the iliac crest osteocutaneous or osteomyocutaneous free flap is reported. The radial forearm free flap was used to resurface the resected portion of the tongue to provide maximum mobility and sensation. The lingual nerve was the recipient nerve for anastomosis to the antebrachial cutaneous nerves in all but one case. The iliac bone was used to reconstruct the mandible, with the iliac skin paddle or the internal oblique muscle used to reconstruct the neoridge. This combination of flaps was used in 10 patients. There was one flap failure due to vascular kinking from "piggybacking" the iliac crest to the distal end of the radial forearm flap. As a result, the use of two separate sets of recipient vessels is now advocated. Although a single composite free flap offers an excellent form of oromandibular reconstruction in most cases, it has been shown that oral function deteriorates when large areas of anesthesia are present in the oral cavity. We believe that this combination of two free flaps offers an opportunity for superior function in select patients with significant glossectomy and/or large mucosal defects.

Anastomosis, Surgical↗
PubMed1991

Oromandibular reconstruction using microvascular composite free flaps. Report of 71 cases and a new classification scheme for bony, soft-tissue, and neurologic defects.

We describe 71 cases of oromandibular reconstruction using microvascular composite free flaps. There was an overall flap success rate of 94%, while 97% of the patients in this series had their mandibles reconstructed with free vascularized bone flaps. Fifteen patients were rehabilitated with implant-borne dental prostheses. Primary repair of discontinuity defects of the inferior-alveolar nerve using a variety of nerve grafts was performed in 16 patients. A new classification scheme for composite defects of the oral cavity involving bone, soft tissue, and neurologic defects is proposed and applied in the description of each of the patients in this series.

Adult↗
PubMed1991

The rectus abdominis free flap in head and neck reconstruction.

The rectus abdominis musculocutaneous free flap, based on the deep inferior epigastric artery and vein, has been used widely in reconstruction of the breast and extremities. The number of reports on its applications in the head and neck is limited. The rectus abdominis free flap is one of the most versatile soft-tissue flaps. The deep inferior epigastric artery and vein are long, large-diameter vessels that are ideal for microvascular anastomoses. The area of skin that can be transferred is probably the largest of all flaps presently in use. The versatility of this donor site is due to the ability to transfer large areas of skin with varying thicknesses and varying amounts of underlying muscle. We have successfully used this flap in 15 consecutive patients to reconstruct defects of the neck, face, mouth, pharynx, skull base, and scalp. No major complications involving either the recipient or donor sites occurred. The literature on the use of the rectus abdominis flap in head and neck reconstruction is reviewed in detail. The advantages and disadvantages of this soft-tissue free flap are thoroughly discussed in an effort to better define its proper place among the reconstructive options available to the head and neck surgeon.

Adult↗
PubMed1991

The combined latissimus dorsi-scapular free flap in head and neck reconstruction.

Microvascular free tissue transfer techniques offer great versatility in the selection of tissue for reconstruction of head and neck defects. The system of flaps based on the subscapular artery and vein provides the widest array of composite free flaps. The possible flaps that can be harvested based on this single vascular pedicle include the scapular and parascapular skin flaps, the serratus anterior and latissimus dorsi muscle flaps, and the lateral scapular bone flap. In addition, a segment of vascularized rib can be transferred with the serratus anterior and latissimus dorsi muscles. Large cutaneous defects can be resurfaced by combining the latissimus dorsi and scapular flaps. Another advantage of this combined flap is the independent vascular pedicles of its components, which allow freedom in orientation of the various tissue segments. Thus, the combined flap can be helpful in reconstructing complex three-dimensional composite defects of the head and neck. In addition, by reinnervating the muscle portions of this flap, bulk can be preserved and an improved functional reconstruction of the oral cavity achieved. A review of the literature shows three previous reports utilizing this combination of flaps in five patients. We report the use of the combined latissimus dorsi-scapular free flap in six patients to reconstruct massive composite defects of the oral cavity, midface, and scalp. There was one flap failure, which was successfully reconstructed with the contralateral latissimus dorsi-scapular flap. The anatomy of this flap is reviewed, and the indications for its application are discussed.

Adult↗
PubMed1991

Temporal factors affecting the secondary critical ischemia of normothermic experimental skin flaps.

In free tissue transfer surgery all flaps are subjected to a primary ischemic episode prior to reperfusion. Some flaps may fail due to a second ischemic insult in the postoperative period. The maximum allowable time for salvage of such failing flaps is referred to as the secondary critical ischemia time. Unilateral abdominal island skin flaps based on the superficial inferior epigastric vessels were raised in 96 Sprague-Dawley rats. Animals were divided into 24 groups of four rats each. Normothermic ischemia was produced by applying microvascular clamps to the vascular pedicles. The flap groups were subjected to combinations of primary ischemia, reperfusion, and secondary ischemia. Flap survival was assessed on the seventh postoperative day. Flap survival decreases significantly with increased primary and/or secondary ischemia time and decreased reperfusion period. Moreover, a longer primary ischemia and/or shorter reperfusion decrease the tolerance of the flap to a second ischemic insult.

Animals↗