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Biomedical subjects

M L Urken

Publications and source records attributed to M L Urken.

At least 91 records · Page 5Linked to original sources
PubMed1991

The lower trapezius island musculocutaneous flap revisited. Report of 45 cases and a unifying concept of the vascular supply.

The lower trapezius island musculocutaneous flap is valuable in head and neck reconstruction. It offers thin, pliable tissue and a long arc of rotation to reach virtually any defect in the head and neck. Recent reports have shown unacceptably high rates of failure and have questioned the reliability of the vascularity. We report our experience with 45 reconstructions using the lower trapezius island musculocutaneous flap. The literature is reviewed and the vascular anatomy is described in detail. The concept of angiosomes is applied to the trapezius muscle to help explain the reasons for flap failure and to provide guidelines for flap design and harvest.

Face↗
PubMed1991

Composite free flaps in oromandibular reconstruction. Review of the literature.

The transfer of vascularized bone containing free flaps is the most effective method of achieving a functional oromandibular reconstruction in the primary setting. All of the reported series on mandibular reconstruction using microvascular free flaps, totaling 513 cases, are reviewed. The collective success rates of free flap transfers compiled from these series have steadily increased to 96% during the latter portion of this review. The experimental studies demonstrating the viability of vascularized bone following an ischemic insult are presented. The issues regarding primary and secondary mandible reconstruction are reviewed. Each of the eight donor sites for vascularized bone are discussed and rated with respect to the ideal qualities of the bone and soft-tissue components of a composite free flap to achieve an optimal oromandibular reconstruction.

Bone Transplantation↗
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↗
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

Jejunal transplantation for pharyngoesophageal reconstruction.

The reconstruction of circumferential and noncircumferential defects of the pharynx and cervical esophagus remains a challenging problem. A variety of different techniques are presently in use for this reconstruction. Free jejunal autografts were the first tissue to be transferred to the head and neck using microvascular techniques. A review of the literature on free jejunal autografts provides a collective experience that permits evaluation of the success rates and complications of the procedure. The results of this review reveal that this method of reconstruction is highly successful in restoring various ablative defects with an acceptable morbidity.

Animals↗
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↗
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↗