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Biomedical subjects

Y B Tang

Publications and source records attributed to Y B Tang.

At least 19 recordsLinked to original sources

Reconstruction of the voice after laryngectomy.

Voice reconstruction and rehabilitation are important for quality of life for patients after surgical ablation of tumors in the larynx or pharynx. In addition to the esophageal voice, the artificial larynx, and external voice devices, the following procedures have been developed: (1) after laryngectomy with preservation of pharynx, neoglottis or TEP can be performed; (2) after laryngopharyngectomy a forearm flap with TEP, or a jejunal transfer with TEP or voice tube shunt can be selected; and (3) after laryngopharyngoesophagectomy, either pharyngogastrotomy with TEP, or colon segment interposition with TEP can be employed. The voice tube shunt is improving, and allograft transplantation is currently under investigation.

Esophagus↗

Replantation of the thumb, especially avulsion.

In replantation for avulsion amputation of the thumb, high survival rate of replanted digits depends on good debridement, good arterial repair with vein grafts or neurovascular bundles, and good coverage, with loose closure of the wound. The functional success depends on liberal use of nerve and tendon grafts or transfer; subsequent procedures, such as tenolysis and opponensplasty; and backup procedures for cases with severe soft tissue avulsion or long ischemic periods. All thumb amputations should be explored in the operating room for evaluation of replantability. If it is still questionable, an experienced microsurgeon should be consulted to choose between replantation and an alternative reconstructive procedure.

Adolescent↗

Microcirculation of a venous flap: an experimental study with microspheres in rabbits.

In recent years, it has been found that maintenance of venous circulation alone may support a small flap with no direct arterial inflow. The clinical application of a venous flap has potential in the field of microsurgery. The purpose of this study was to evaluate the haemodynamics within a pedicled venous flap in rabbits, compared with those of a composite graft. Pedicled venous flaps and composite grafts were raised from the abdominal walls of 30 adult New Zealand rabbits. Flap survival was measured and recorded and blood flow studies with microspheres were done for seven days. The viability of the pedicled venous flaps was much better than that of the composite grafts. At two weeks 24 of the venous flaps (80%) showed more than 75% surviving, but 29 (97%) of the composite grafts had less than 25% surviving. The results suggest that the blood flow through a patent vein maintained in a venous skin flap can provide enough nutrients for the flap to survive during the initial three days until neovascularisation. The venous flap receives more blood flow than a composite graft. We conclude that a venous flap depends on blood supply from the axial vein in addition to neovascularisation to maintain its survival.

Animals↗

Microvascular vastus lateralis muscle flap for chronic empyema associated with a large cavity.

Thoracic empyema can be disabling and may need microvascular free flaps in some intractable cases. After repeated failure of conventional thoracic surgical procedures, 2 patients with empyema were treated with microvascular free vastus lateralis muscle flaps for obliteration of the large empyema cavity. The reconstruction was successful in wound closure and eradication of infection. The donor site morbidity was minimal, and the patients resumed normal daily activities. Microvascular vastus lateralis muscle flap is the best option if free flaps are required for reconstruction of empyema.

Aged↗

Microvascular prefabricated free skin flaps for esophageal reconstruction in difficult patients.

BACKGROUND: Reconstruction of the esophagus for complicated benign stricture or after resection of malignant lesion is still a challenge for surgeons. When abdominal viscera cannot be used, skin flaps are selected for esophageal reconstruction. However, skin flaps for esophageal reconstruction are notorious for leakage, and have not been widely accepted. Prefabrication before microvascular transfer to its final site can improve the result of esophageal reconstruction when skin flaps are used. METHODS: Eight patients with complicated corrosive esophagitis had been treated with prefabricated skin flaps for esophageal reconstruction. The procedures are described in detail. RESULTS: All patients healed well without leakage. The barium study showed smooth passage. There was no dysphasia or regurgitation after education. Pulmonary complication happened in only 1 patient. Revision for the distal anastomosis was required in 1 patient due to narrowing. When the skin tube is long, the patients need water (or soup) to facilitate swallowing and occasionally use their hand to help the food passage. This method has the following advantages: (1) healing of the long suture line before transfer to withstand the intestinal juice; (2) reliable viability in the distal part of the flap, especially when an extended length of the flap is required; (3) more length of stable tissue for two-layered, tension-free anastomosis at the junction of skin and gastrointestinal mucosa to prevent leakage; and (4) the flap can be placed in the substernal position to meet the aesthetic requirement of young patients. The disadvantage was the staged operations. However, after prefabrication the transfer becomes safe and free of leakage. The overall morbidity is minimal. CONCLUSIONS: In rare situations when skin flaps are used for esophageal reconstruction, prefabrication provides advantages over conventional one-stage methods, although it needs additional procedures. This method is a combination of conventional technique and microsurgery.

Adult↗

Prefabrication of jejunum for challenging reconstruction of cervical esophagus.

A significant benefit exists for a jejunal replacement of the cervical esophagus, if indicated. The absence of available recipient vessels may impede free tissue transfer. If vascular induction between a vascular carrier and the selected jejunal segment is done as a kind of flap prefabrication, the jejunal interposition flap can be used without the need for complex microsurgery.

Adult↗

Economy of donor site incisions: multiple free flaps of the subscapular family for extensive extremity wounds and bilateral foot defects.

One of the most important goals of modern microsurgical reconstruction is to decrease donor site morbidity as much as possible. With free flaps for lower limb reconstruction, economy of donor sites was designed and performed in 39 patients. Among these 39 patients, 17 had multiple flaps raised from a single incision for reconstruction of multiple defects in one or both lower extremities. Microvascular reconstruction of multiple defects is a challenging problem, particularly if it is to be performed simultaneously. The patients were followed for more than 3 years. Immediate complications and long-term disabilities were analyzed. From the data we conclude that this method has the following advantages: (1) economy of donor site incisions, (2) less harvest time, and (3) availability of any composite tissue for transfer. Donor site morbidity can be reduced by good planning, careful dissection, meticulous hemostasis, and adequate postoperative management.

Adult↗

Posterior interosseous flap and its variations for coverage of hand wounds.

BACKGROUND: Conventional posterior interosseous flap has the disadvantage of partial or even complete necrosis of the flap when there is anatomical variation or contusion around its distal pedicle. To make it a more reliable flap, three types of auxiliary procedures were designed. METHODS: (1) When there is congestion after inset of the distally based flap, an additional venous anastomosis was carried out. (2) When there is anatomical variation so that a distally based flap could not be raised without compromising the nerve branches, or when contusion was found around the distal pedicle, the flap was changed into a free flap. This design is also indicated for coverage of the distal fingers. (3) When the patient is elderly with possible peripheral arterial disease, the flap was raised with a wide base, incorporating the branches of both the anterior and posterior interosseous arteries. There were eight, 36, and five patients in each group, respectively. RESULTS: There was only one failure in the free flap group. No partial necrosis of the flap was found. Other complications were analyzed. CONCLUSION: With these backup procedures, the posterior interosseous flap can be more widely used with safety. By combining various reconstructive armaments, the result of a conventional procedure can be improved.

Adolescent↗

Turning of nerve growth cones induced by the activation of protein kinase C.

Pathfinding by growing nerve processes in the developing nervous system depends on the turning response of the growth cone to extracellular guidance cues. Embryonic spinal neurons were prepared from 1-day-old Xenopus embryos. After 4 h incubation, a repetitive pulse application was used to produce microscopic chemical gradients near the growth cone. A micropipette containing the protein kinase C (PKC) activator 12-O-tetradecanoyl-phorbol 13-acetate (TPA) or phorbol 12,13-dibutyrate, produced a significant growth cone turning response. A micropipette containing adenosine 5'-triphosphate (ATP) also induced growth cone turning towards the pipette tip. H-7, a PKC inhibitor, inhibited the ATP-induced turning response of the growth cone. Our results suggest that the activation of PKC in developing motoneurons may induce the turning response of growth cones.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗

Chronic osteomyelitis of the spine managed with a free flap of latissimus dorsi. A case report.

STUDY DESIGN: A patient with intractable spinal osteomyelitis who underwent surgery 12 times with persistent exposed bone is presented. OBJECTIVES: To demonstrate the effectiveness of free-flap grafting for managing difficult spinal osteomyelitis wounds. SUMMARY OF BACKGROUND DATA: Conventional procedures can usually achieve wound closure, but they may not work for advanced cases. METHODS: A free latissimus dorsi flap was transferred for reconstruction. The muscle component was used to obliterate the dead space and cover the exposed bone, and the skin component was used for tension-free closure of the wound. RESULTS: The wound healed dramatically. There was no recurrence of infection at 2-year follow-up evaluation. CONCLUSIONS: For an intractable spinal osteomyelitis wound, a free flap should be considered, although the surgery is difficult. Technical precautions in performing this operation are given.

Chronic Disease↗

Microvascular free posterior interosseous flap and a comparison with the pedicled posterior interosseous flap.

The posterior interosseous flap has been used as a pedicled flap for coverage of hand wounds. However, the pedicled flap is associated with partial or even complete loss when there is venous congestion. This happens because it depends on retrograde venous drainage. Another pitfall of the pedicled posterior interosseous flap is the undetected damage to the communicating vessels between the anterior and posterior interosseous arteries before surgery. This would result in failure if the flap is used as a distally based flap. Thirty-four patients had been reconstructed with the microvascular free posterior interosseous flap. The free flap has a large draining vein. Flap survival rate was 97%. There was no venous congestion and no partial loss of the flap. It is thin, sensate, and reliable. The free posterior interosseous flap is indicated for coverage of the following wounds: (1) first web space and thumb, (2) radial side of the index and ulnar side of the small finger if a cross-finger flap cannot be used, and (3) defects at the dorsum of multiple fingers. It can also be used as a free fascial flap. The free posterior interosseous flap provides a reliable option for coverage of hand wounds. Previously, another 14 patients with hand wounds had been reconstructed with a pedicled posterior interosseous flap. The results of pedicled and free posterior interosseous flaps are compared.

Adolescent↗

Salvage of a devascularized digit with free arterialized venous flap: a case report.

Significant soft tissue and vascular loss is always encountered in salvage of a devascularized digit that has sustained crush or avulsion injury. Ideal reconstruction should include repair of the vascular defect and provision of stable soft tissue coverage simultaneously in a single operation to facilitate early recovery and early rehabilitation. A venous flap is a composite cutaneous flap that contains a segment of vein traversing it. A free venous flap is used in a devascularized digit to cover the soft tissue defect and restore the digital circulation by perfusion of arterial blood through the flap's venous network (i.e., free arterialized venous flap). Satisfactory result, both for the flap and for the digit, is obtained. The free arterialized venous flap is a useful, up-to-date option for such dual-purpose reconstruction.

Debridement↗

Endoscopically-assisted duodenal feeding tube placement using a nasogastric tube: preliminary two-year experience.

Our initial 2-year experience using a new technique of nasoduodenal feeding tube placement with a soft nasogastric tube is presented. This technique was used for patients with major burns to initiate early, safe enteral feeding. With the use of double loops in the tube and endoscopic assistance, the placement of the nasogastric tube beyond the second portion of the duodenum was accomplished in approximately 20 minutes. A method of transpyloric duodenal intubation using a soft, unstented nasogastric tube that allowed rapid bedside nasoduodenal intubation, with the patient in the supine position, was used. The tube placement technique minimizes the suffering of critically ill patients and the labor of clinicians performing the tube placement.

Burns↗

Fournier's gangrene as the initial clinical manifestation of diabetes mellitus.

Fournier's gangrene is a true urosurgical emergency requiring prompt surgical intervention. Diabetes mellitus is not uncommon among the sufferers of Fournier's gangrene. In rare instances, Fournier's gangrene may present as the initial clinical manifestation of diabetes mellitus in an undiagnosed diabetic. An unknown, and hence uncontrolled, diabetic situation and its associated pathophysiologic changes will adversely aggravate the infectious process. Alertness to this possibility together with efforts to control the diabetes and urosurgically manage the gangrene afford the promise of successful cure.

Adult↗

Pseudocyst formation after trapezius myocutaneous flap reconstruction: management with chemical obliteration.

A trapezius myocutaneous flap is frequently used in head and neck reconstruction surgery. Pseudocyst formation over the flap donor area after its dissection is a rare occurrence. When a cyst occurs after flap application in reconstructive surgery for head and neck malignancies, or is noted concomitantly with a local recurrence of a head and neck malignancy, differentiation between malignant effusion and pseudocyst is important. Differentiation is made by cytologic and biochemical analyses of the cystic contents. Instillation of a chemical irritant can successfully obliterate such pseudocysts.

Aged↗

Transposed replantation of fingers at forearm bones in severe segmental injuries across the hand and wrist.

There are situations in which amputated hands or fingers cannot be replanted directly back to their original positions. When there is severe segmental injury across the hand and wrist but one or several fingers are still healthy, the fingers can be selected to be replanted at the forearm bones to restore pinch function. This is different from the toe to antebrachial stump transplantation presented by Dr. Vilkki. From the results in four patients, the following conclusions are drawn: (1) When the fingers are replanted at the forearm bone(s), only pinch function can be obtained. There is no opposition. (2) Grip function is weak because the intrinsics are lost and only a few fingers are replanted. The forearm bones are often shortened, as are the flexors. (3) Of particular importance is the creation of a large web space between the radial digit and ulnar digit(s), because fingers are longer than toes. (4) The sensory recovery is not so good as in ordinary finger replantation. However, this is a salvage procedure. Regardless of these facts, the patients are still satisfied with the results out of such severe injuries. With good pinch function, not only are they independent in daily life, but they also can do a lot of work. It is a worthwhile procedure. A functional prosthesis can be added distally after this replantation.

Adult↗