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Biomedical subjects

G R Tobin

Publications and source records attributed to G R Tobin.

67 records · Page 4Linked to original sources
PubMed1982

Use of the rhomboid major muscle flap for esophageal repair.

A 16-year-old boy sustained vehicular blunt trauma with delayed esophageal rupture that resulted in empyema and an esophagopleurocutaneous fistula. Diverting esophagostomy, gastrotomy, and transpyloric jejunostomy were performed, and these procedures permitted satisfactory nutritional support of the patient. Staged direct closure of the esophagus buttressed by a rhomboid muscle flap preserved normal esophageal function. Both clinical application and cadaver dissections have demonstrated that the rhomboid flap has an excellent blood supply and that it can be used to repair lesions on either side in the upper half of the esophagus. Because this flap is extrathoracic, it is not usually distorted by intrathoracic sepsis or previous thoracic incisions. The rhomboid major muscle flap is an excellent alternative to conventional autogenous grafts for esophageal repair.

Accidents, Traffic↗
PubMed1981

The biceps femoris myocutaneous advancement flap: a useful modification for ischial pressure ulcer reconstruction.

We describe a modification of the biceps femoris myocutaneous flap for reconstruction of ischial pressure ulcer defects. In this modification, all neural and vascular pedicles are preserved and the flap is advanced into the ischial defect rather than transposed as described in the literature. With this method, no transferred tissue is lost. Besides ensuring good tissue survival, the flap preserves a maximum number of reconstructive options in the event of ischial pressure ulcer recurrence. These advantages make the biceps femoris myocutaneous advancement flap our first choice for reconstruction of ischial pressure ulcer defects.

Humans↗
PubMed1981

The split latissimus dorsi myocutaneous flap.

Consistent proximal branching of the latissimus dorsi neurovascular anatomy permits surgical splitting of the myocutaneous unit into two flaps. Either or both branches of the split flap can be independently transferred. Experimental and clinical applications of this flap, which illustrate several of its uses and advantages, are presented. Applications include simultaneous provision of cover and lining flaps for head and neck reconstruction, motor transfers with split muscle branches, preservation of motor function in the flap donor site with one split muscle branch, and microvascular free tissue transfer of the branched flap or of individual branches.

Adult↗
PubMed1981

Emergency abdominal wall reconstruction with polypropylene mesh: short-term benefits versus long-term complications.

The acute replacement of full-thickness abdominal wall has been facilitated by polypropylene mesh (Marlex) (PPM), allowing debridement of nonviable tissue and restoration of abdominal wall integrity without tension. However, no substantial long-term follow-up has been reported on the definitive wound coverage after the use of PPM in open wounds. Since 1976, we have placed PPM in 31 patients; 25 for infectious complication, three for massive bowel distension preventing abdominal closure, and three for shotgun wounds with extensive tissue loss. In 29 of 31 patients, the mesh was placed in heavily contaminated wounds; extensive fasciitis was present in 23 patients and 21 had intra-abdominal abscesses. Following mesh placement, 23 reoperations were required for continuing complications. No patients eviscerated, despite these multiple procedures. Polypropylene mesh was highly effective in restoring abdominal wall continuity. Despite advantages when PPM was used, significant long-term problems developed. Seven patients died from their primary illness in the postoperative period. Nine wounds were closed by granulation and subsequent split-thickness skin grafts. All nine developed mesh extrusion and/or enteric fistulae. Nine wounds healed by secondary intention, six developed enteric fistulae or continuing mesh extrusion. Full-thickness flap coverage after granulation provided the best means of wound closure. Polypropylene mesh had significant early advantages for providing abdominal wall integrity even in the presence of severe infection. However, long-term problems were common when wounds were closed to skin grafts or secondary intention. If the mesh cannot be completely removed, strong consideration should be given to myocutaneous flaps for coverage after the primary illness has resolved.

Abdominal Injuries↗
PubMed1981

The intramuscular neurovascular anatomy of the latissimus dorsi muscle: the basis for splitting the flap.

This study identifies and describes a consistent proximal branching of the neurovascular supply to the latissimus dorsi muscle. This anatomical feature makes possible splitting the muscle and overlying cutaneous territory into independent branched musculocutaneous units. A parallel study of neurovascular anatomy in dogs suggests that this animal is an appropriate model for testing and developing clinical applications of the split latissimus dorsi flap.

Anatomy, Comparative↗
PubMed1980

Collagen biosynthesis in healing wounds of the spinal cord and surrounding membranes.

Kinetics of collagen synthesis and deposition were studied in the canine spinal cord, pia mater, and dura mater and in wounds of these tissues over the first 8 weeks. Little collagen is present in unwounded spinal cord compared with surrounding mesenchymal membranes. Collagen synthetic potential was found within the spinal cord, a tissue of neurectodermal origin. Rate of collagen synthesis per collagen content in the unwounded spinal cord was high. This synthetic rate was as high as that of wounds at their maximum collagen synthetic rates. Substantial deposition of collagen followed spinal cord wounding. Wounding the spinal cord, pia mater, and dura mater caused substantial elevations in rates of collagen synthesis in each tissue. These synthetic rates remained at maximum levels throughout the 8-week study, a prolonged period when compared with other wounded tissues previously studied. The role of mesenchymal tissue physiology in central nervous system wound healing is discussed. The potential value of these findings for further studies and for experimental manipulation of the healing process in spinal cord and central nervous system wounds is presented. Implications of these findings on the hypothetical relationship of scar to spinal cord and central nervous system regeneration are noted.

Animals↗
PubMed1977

Correction of anomalous subdiaphragmatic inferior vena caval drainage of the right pulmonary veins (scimitar syndrome).

Correction of anomalous infradiaphragmatic inferior vena caval drainage of the right pulmonary veins can be repaired under conventional cardiopulmonary bypass by placing a circumferential tape below the diaphragm between the hepatic veins and the scimitar vein entrance. During repair, creation of an atrial septal defect in the distorted septal-left atrial junction of scimitar syndrome is facilitated by first incising the anteromedial aspect of the fossa ovalis to better delineate the optimal posterolateral margin. A case history illustrates the technique.

Child↗
PubMed1976

A neuromuscular basis for development of indirect inguinal hernia.

Specialized portions of the transversus abdominus muscles act on the internal inguinal rings and produce a closure mechanism during voluntary abdominal muscular activity. Abdominal muscular contractions may have a protective influence against development of indirect inguinal hernia. It follows, therefore, that injury or inactivation of this mechanism may be an etiologic factor in the development of indirect inguinal hernia. One cause of injury to this mechanism is by denervation and regional muscle paralysis occurring during a surgical procedure. Surgical denervation appears to have caused an indirect inguinal hernia in one of the authors.

Adult↗
PubMed1976

Relationship of splanchnic blood flow and portal venous resistance to elevated portal pressure in the dog.

To determine the relationship of splanchnic blood flow and portal venous resistance to elevated portal pressure, in situ perfusion of the splanchnic circuit was carried out in 12 freshly killed dogs at varying perfusion rates and degrees of acute and chronic portal vein constriction. In six normal dogs before being killed, portal pressure averaged 8-8 +/- 1-2 mmHg and portal flow 658 +/- 81 ml/min. In the absence of portal vein constriction, increasing splanchnic perfusion to 1800 ml/min, minimally raised portal pressure (12-8 +/- 1-5 mmHg). With progressive acute constriction of the portal vein, however, comparable perfusion rates lead to progressively higher portal pressure levels and with greater than 90% constriction, portal pressure was greater than 30 mmHg with minimal elevation in splanchnic flow rate. In six other dogs before being killed but live to nine weeks after placement of an ameroid constrictor on the portal vein, portal pressure averaged 13-6 +/- 1-4 mmHg or slightly higher than in normal dogs (P greater than 0-02). Mesenteric venography and necropsy findings uniformly demonstrated 90% occlusion of the portal vein with extensive portasystemic collateralization. With increased perfusion of the splanchnic bed, portal pressure rose rapidly to approximately 35 mmHg with a flow rate of 1 800 ml/min.. These data suggest that, in disorders where resistance to transhepatic portal flow is marked, a small increment in splanchnic blood flow, which normally exerts little or no influence on portal pressure, promotes profound portal hypertension and may account for spontaneous 'rupture' of oesophageal varices. On the other hand, where resistance to transhepatic portal flow is mild but splanchnic blood flow is markedly hyperdynamic, reducing inflow may be sufficient to ameliorate extreme portal hypertension and its sequelae.

Animals↗
PubMedDate not supplied

The hairless mouse ear: an in vivo model for studying wound neovascularization.

Microvascular ingrowth into damaged tissue is an essential component of the normal healing process. In fact, wound therapy is often aimed at promoting neovascularization. However, little is known about the mechanisms that regulate microvascular ingrowth into a healing wound. This limited knowledge is largely due to the lack of adequate models in which microvascular ingrowth can be quantitatively analyzed throughout the healing process. To address this deficiency, we developed a model in which a wound was created on the ear of the hairless mouse-a well established model for directly viewing and measuring skin microcirculation. While the animals were under ketamine and xylazine anesthesia, 2.25 mm diameter full-thickness wounds were created on the dorsum of hairless mouse ears down to but not including the cartilage (0.125 mm depth). With the use of video microscopy and computer-assisted digitized planimetry, the precise epithelial and neovascular wound edge was viewed and measured regularly throughout healing. Therefore, this model can provide objective data on wound epithelialization and neovascularization throughout healing. This model was used to examine the effect of topical wound agents on epithelialization and neovascularization. Differential effects by these anti-microbial agents on these two processes were observed, which suggests clinical implications for their use.

Journal Article↗
PubMedDate not supplied

Ketanserin accelerates wound epithelialization and neovascularization.

We investigated the acute effects of topical ketanserin, a 5-HT(2) (serotonin) receptor blocker, on wound epithelialization and vascularization with the use of the hairless mouse ear model. Varying concentrations of Ketanserin (0%, 0.2%, 2.0%, 20% weight/volume) were administered to standardized full-thickness skin wounds on the dorsum of the hairless mouse ear immediately after surgery and daily thereafter. With the use of video microscopy and computer-assisted planimetry, vascularization and epithelialization were traced every third day until the wounds were fully healed. Arteriole diameters at selected sites near the skin wound were measured before wound creation and after wounding. It was concluded that topically administered ketanserin significantly accelerates both the vascular (p < 0.001 at 2% and 20% concentrations) and epithelial (p < 0.001 at 20% concentration) rates of wound healing in full-thickness nonpathologic skin wounds. Vasodilation of terminal arterioles was not a major response to Ketanserin. Faster epithelialization was possibly due to direct effect of ketanserin on epithelial cells.

Journal Article↗
PubMedDate not supplied

Repair of infected pseudoaneurysm with aortic arch replacement after orthotopic heart transplantation.

Arterial wall infections are rare after orthotopic heart transplantation. An infected pseudoaneurysm developed in a patient at the site of aortic cannulation 6 months after his transplant procedure. Debridement of the infected tissue necessitated removal of a major portion of the aortic arch and reconstruction with in situ placement of a synthetic polyester (Dacron) graft. In situ placement of grafts is a controversial form of treatment of arterial wall infections in other portions of the aorta. Because of the extensive nature of the infection and its site, no other option was available. This patient represents the first reported case of successful aortic arch replacement for an infected pseudoaneurysm after orthotopic heart transplantation.

Adult↗