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Biomedical subjects

G R Tobin

Publications and source records attributed to G R Tobin.

At least 55 records · Page 3Linked to original sources
PubMed1989

Pectoralis major muscle-musculocutaneous flap for chest-wall reconstruction.

Pectoralis major muscle and musculocutaneous flaps are the most frequently selected for the ventral chest wall, sternum, and anterior mediastinum because of their proximity, reliability, and versatility. These advantages are derived from consistent anatomic features that allow knowledgeable surgeons to use a variety of flap designs tailored to defect needs. The flaps can be transferred on either thoracoacromial or internal mammary vascular pedicles and can be segmentally split to achieve defect closure while retaining portions of the muscle in situ to preserve donor motor function and surface form. The musculocutaneous paddles can be placed in a variety of locations and extended beyond the muscle borders to meet specific defect needs. This anatomic versatility gives pectoralis major muscle and musculocutaneous flaps a most useful role in the reconstruction of defects of the sternum and anterior mediastinum, defects of the ventral and lateral chest wall, and intrathoracic defects such as empyema cavities and bronchopleural fistula. A detailed knowledge of surgical anatomy is essential for optimal application of these flaps in the full spectrum of clinical needs.

Humans↗
PubMed1988

Vaginal and pelvic reconstruction with distally based rectus abdominis myocutaneous flaps.

This report introduces a new method of vaginal reconstruction using a single rectus abdominis myocutaneous flap based distally. Applications of this flap in reconstruction of major abdominal wall and pelvic defects, such as hemipelvectomies, are also described. The flap is designed to carry a paddle of upper abdominal skin on a distally based muscle and vascular pedicle. Advantages of this flap design are (1) the technique is straightforward and rapid, (2) flap viability is reliable, (3) the epigastric skin-fascial donor defect preserves the anterior rectus fascia distal to the linea semicircularis, which prevents hernia, (4) a large arc of rotation is provided, and (5) the epigastric donor site does not interfere with colostomy and urinary conduit stomas in the pelvic exenteration patient. We have done 11 vaginal reconstructions and 9 major pelvic defect reconstructions with this flap during the last 3 1/2 years. In these 20 patients, the only complications were two partial flap losses. No major flap losses or ventral hernias occurred.

Abdominal Muscles↗
PubMed1986

Enhancement of epidermal regeneration by biosynthetic epidermal growth factor.

Epidermal regeneration depends on mitosis and migration of keratinocytes. Epidermal growth factor is known to stimulate growth of keratinocytes in vitro, thus it might be expected to promote wound healing. The results of this study show that topical application of biosynthetic human epidermal growth factor accelerates epidermal regeneration in split-thickness wounds and partial-thickness burns. The significant enhancement of epidermal regeneration suggests the potential for clinical use of epidermal growth factor for accelerating healing of burns, wounds from trauma, diabetic ulcers, skin graft donor sites, and others.

Animals↗
PubMed1986

One-stage simple mastectomy with immediate reconstruction for high-risk patients. An improved technique: the biologic basis for ductal-glandular mastectomy.

The heterogeneity of human breast carcinoma appears to be a cumulative interrelationship of genetic and environmental factors that may be identifiable with a high risk for carcinogenesis. Until breast cancer prevention is realized, one-stage total ductal-glandular mastectomy with immediate reconstruction may be offered as an alternative to simple mastectomy for women at high risk for developing cancer. This technique affords the complete extirpation of breast tissue at a deep plane with flaps that are identical in thickness to those elevated in classic mastectomies for invasive cancer. Breast reconstruction with submuscular prostheses in a one-stage procedure gives an aesthetically acceptable result. The role of ductal-glandular mastectomy as prophylaxis for invasive carcinoma warrants future prospective trials.

Adult↗
PubMed1985

Comparison of prosthetic materials for abdominal wall reconstruction in the presence of contamination and infection.

Abdominal wall defects resulting from trauma, invasive infection, or hernia present a difficult problem for the surgeon. In order to study the problems associated with the prosthetic materials used for abdominal wall reconstruction, an animal model was used to simulate abdominal wall defects in the presence of peritonitis and invasive infection. One hundred guinea pigs were repaired with either polytetrafluorethylene (PTFE) or polypropylene mesh (PPM). Our experiments included intra-operative contamination with Staphylococcus aureus. We found significantly fewer organisms (p less than 0.05) adherent to the PTFE than to the PPM when antibiotics were administered after surgery, as well as when no antibiotics were given. In the presence of peritonitis, we found no real difference in numbers of intraperitoneal bacteria present whether PTFE or PPM was used. In all instances, the PTFE patches produced fewer adhesions and were more easily removed. From these experiments, it appears that PTFE may be associated with fewer problems than PPM in the presence of contamination and infection.

Abdominal Muscles↗
PubMed1985

Vastus medialis myocutaneous and myocutaneous-tendinous composite flaps.

This report describes a new myocutaneous territory and introduces a new myocutaneous flap based on the vastus medialis muscle. Dissection, arterial dye perfusion, and specimen angiography of 32 fresh cadaver legs defined a vastus medialis myocutaneous territory directly overlying the muscle and also defined a segment of quadriceps femoris tendon vascularized by the muscle. This vascular unit provides a myocutaneous flap for closure of anterior knee defects. This flap can also be designed as a composite myocutaneous-tendinous flap by inclusion of the vascularized quadriceps femoris tendon segment, which allows reconstruction of missing patellar tendon segments. The distal advancement flap design with retention of motor innervation preserves vastus medialis contribution to knee extension. Clinical applications of vastus medialis myocutaneous and myocutaneous-tendinous flaps are illustrated by their use in three patients with knee defects and patellar tendon losses. The potential value of vascularized tendon (versus vascular free tendon grafts) for patellar tendon reconstruction is discussed.

Adult↗
PubMed1985

Pectoralis major segmental anatomy and segmentally split pectoralis major flaps.

This report presents the anatomic studies, animal studies, and initial clinical experience that provide a basis for splitting pectoralis major muscle and myocutaneous flaps into independent segmental subunits. The anatomic study of 105 human cadaver pectoralis major muscle and myocutaneous units and their neurovascular supply indicated a consistent segmentation of muscle morphology, neurovascular supply, and myocutaneous territory. Three major independent segments (clavicular, sternocostal, and external) were identified. These findings provide the anatomic basis for segmentally splitting pectoralis major flaps, and the surgical technique that evolved is described. Segmentally split pectoralis flaps were experimentally tested in animals and subsequently used in 36 clinical reconstructions. The variety of forms of segmentally split pectoralis major flaps used in this series is described and analyzed. The technique of segmentally splitting flaps provides a method both for leaving innervated muscle segments in situ to preserve donor motor function and for deriving two independent flaps from one muscle.

Animals↗
PubMed1985

Hemisoleus and reversed hemisoleus flaps.

This paper reports an anatomic study of the soleus muscle and clinical applications of the findings derived from the study. Soleus neurovascular anatomy was studied in 86 limbs by dissection and specimen angiography. A consistently present bipenniform muscle morphology was found with medial and lateral subunits that had independent distal neurovascular supplies. This anatomic feature allows surgically splitting the muscle for transfer of one-half the muscle as a flap (hemisoleus muscle flaps). A series of 33 patients using both medial and lateral hemisoleus flaps in both proximally and distally based transfer is analyzed and illustrative examples are presented. The primary value of this technique is the ability to retain one-half the innervated soleus muscle in situ to preserve foot plantar flexion power in ambulatory patients. In addition, hemisoleus flaps have an extended arc of rotation as compared with that of conventional soleus muscle flaps.

Female↗
PubMed1985

Epithelial lining methods in esophageal repair: a comparative study using pedicle flaps in cats.

Methods of restoring luminal lining in repair of partial-circumferential esophageal defects were evaluated to compare incidences of strictures and fistulas and quality of surface lining. In cats 50% and 67% circumferential esophageal defects were repaired by direct closure or pedicle flaps (latissimus dorsi) that were unlined (lining restored by epithelialization from wound margins) or that carried lining of normal skin (myocutaneous flaps), skin grafts, or mucosal grafts. Repairs were evaluated for esophagocutaneous fistulas, luminal stricture, flap luminal surface area, and quality of epithelial surface 6 weeks after surgery. Direct closure of 50% circumferential defects was as satisfactory as any flap repair method. Direct closure of 67% circumferential defects caused high incidences of fistulas and strictures, which were lessened by flap reconstructions. Among flap lining methods, normal skin (myocutaneous flaps) gave the lowest incidence of fistulas and strictures and the highest surface quality, but a high incidence of skin paddle loss occurred in this model. Split-thickness epithelial grafts were nearly as satisfactory as myocutaneous flaps, and less lining loss occurred. Epithelialization of unlined flaps gave the poorest results since lining was thin and often incomplete, and wound contraction produced loss of surface area and strictures. The findings are discussed from a perspective of wound healing physiology, and implications for clinical application are presented.

Animals↗
PubMed1984

Experimental and clinical observations of the effects of cytotoxic chemotherapeutic drugs on wound healing.

The administration of perioperative doxorubicin HCl (Adriamycin) had profound effects on wound healing for 5 out of 7 breast cancer patients and 5 of 5 melanoma patients following intravenous and intra-arterial infusional chemotherapy, respectively. The clinical observation of significant reduction in wound tear strength (WTS) and wound tear energy ( WTE ) in the group of patients with cutaneous melanoma initiated this experimental analysis. A study of WTS ( kNm -2) in nontumor-bearing (non-TB) and Morris Hepatoma (MH)-7777 (TB) rats treated with therapeutic doses of Adriamycin (ADR) and methotrexate (MTX) was compared with saline-treated controls. Mean tumor volume (cm3) was unaffected by MTX, while significant tumor inhibition (p less than 0.01) was evident for ADR-treated TB animals. A correlation (r = 0.516, p less than 0.01) was observed for tumor volume and WTS. Separate analysis of TB and non-TB animals identified a significant correlation (r = 0.6259, p less than 0.01) between advancing cachexia in TB rats and WTS. A 21-day analysis was done for 160 animals to determine the effect of MTX and ADR on WTS ( kNm -2) and WTE ( Ncm -1). The presence of MH-7777 significantly (p less than 0.01) reduced WTE for TB animals not treated with chemotherapy. TB animals treated with ADR had significant (p less than 0.01) improvement in WTE at day 21 compared with TB controls. This enhancement in WTE was not observed in rats treated with MTX. These clinical and experimental observations suggest significant retardation of the early phases of wound fibroplasia as determined by WTS and WTE following operative trauma and subsequent administration of therapeutic dosages of cytotoxic agents.

Adult↗
PubMed1983

Reconstruction of complex thoracic defects with myocutaneous and muscle flaps. Applications of new flap refinements.

This report describes reconstructions of complex thoracic defects with myocutaneous and muscle flaps that were modified by several recent refinements of flap design. These refinements comprise a second generation of myocutaneous and muscle flaps, which have substantially increased versatility and extended applications, as compared with the originally described flaps. These refinements include the following: (1) segmentally split latissimus dorsi and pectoralis major flaps, which transfer only one muscle segment as the flap and leave other segments of the same muscle in situ to preserve motor function; (2) pectoralis major fasciocutaneous flaps, which are extended by abdominal skin and fascia to provide longer, larger flaps; (3) reversed pectoralis major and latissimus dorsi flaps, which are supplied by secondary, distal vascular pedicles that permit flap use when the primary vascular supply is interrupted; and (4) island vascular pedicle muscle flaps, which allow intercostal passage for reconstruction of intrathoracic defects and cavities. The anatomic bases for these flap refinements are described, and the advantages provided are discussed.

Adult↗
PubMed1982

One-stage pharyngoesophageal and oral mucocutaneous reconstruction with two segments of one musculocutaneous flap.

This report describes a one-stage technique that provides both cover and lining to mucocutaneous defects of the head and neck with either latissimus dorsi or pectoralis major musculocutaneous units that are split into anatomic segments to create two independent flaps from one musculocutaneous unit. In addition, this technique further refines reconstruction of pharyngoesophageal defects. Techniques of simultaneous mandibular reconstruction with vascularized bone carried on these same segmental flaps are also commented on.

Animals↗