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Biomedical subjects

G G Hallock

Publications and source records attributed to G G Hallock.

At least 127 records · Page 7Linked to original sources
PubMed1991

Recontouring of the lateral forehead using the temporalis muscle.

Contour deformities of the lateral forehead are not uncommon after direct injuries or extirpative procedures, or as a sequela to iatrogenic maneuvers for juxtaposed craniomaxillofacial endeavors. Transposition of noncutaneous local vascularized autogenous tissues for augmentation of these defects has minimal inherent risks and little donor site morbidity. Although the temporoparietal fascia has previously been described as a first choice in this regard, if unavailable due to concomitant injury or absence of the superficial temporal vessels, the temporalis muscle itself provides an excellent second option that deserves consideration.

Adult↗
PubMed1991

Simultaneous transposition of anterior thigh muscle and fascia flaps: an introduction to the chimera flap principle.

A compound flap implies that more than a single tissue structure has been linked together to achieve a common purpose. In this sense then, a composite flap is the simplest form of a compound flap because by definition it incorporates multiple tissue types, but the latter are restricted in that the vascularization of all contained parts are interdependent and inseparable if total viability of the unit is to be maintained. More complex compound flaps may have components with separate vascular sources but remain physically attached, or may be fabricated by joining disparate flaps together using microsurgical methods. The chimeric flap, as still another type of compound flap, differs in that its tissue components may be independently maneuvered, remaining ultimately attached together only by some common regional source vessel or plexus. Concurrent, independent local transposition of the anterior thigh fasciocutaneous flap and rectus femoris muscle flap is used to demonstrate the chimera principle where these disparate flaps have been harvested from the same anterior thigh region.

Accidents, Occupational↗
PubMed1991

Methods for providing vascularized tissue protection of microanastomoses.

Perianastomotic thrombosis following free tissue transfer must be systematically prevented if even routine successes are to be expected. One possible culprit that must be considered is the method of soft tissue closure around the recipient site pedicle that frequently poses a challenge to avoid tension and the resultant compression that may then predispose to such thrombosis. One hundred sixteen consecutive free tissue transfers from 1982 to 1990 were analyzed; simple local soft tissue manipulations to provide adequate coverage were satisfactory in 67% of cases. Local flaps (5%) or extensions of the free flap itself (28%) as a source of vascularized tissues were necessary specifically to avoid this risk for the remainder. Ninety-seven percent of these latter flap alterations were required for the extremities where a paucity of local tissues (as would be expected) most frequently precluded local techniques. An appreciation of this seldom discussed but ubiquitous concern for coverage of the zone of microanastomoses to decrease the risk of thrombosis by intentional inclusion of vascularized tissues should serve to eliminate morbidity further in these complex procedures.

Anastomosis, Surgical↗
PubMed1991

Complications of 100 consecutive local fasciocutaneous flaps.

A resurgence of interest in the fasciocutaneous flap has been predicated on its simplicity, availability, and versatility. Its dependability in addition is documented in this analysis of complications accrued in 100 consecutive local applications. Major complications that required further surgical intervention occurred in 15 percent of patients, with an additional 11 percent of patients suffering other minor untoward events. Lower extremity wounds, particularly with concomitant peripheral vascular insufficiency, had a disproportionate share of complications. Early coverage of the acute wound ensured minimal problems, avoiding the enhanced risk of a contaminated wound. No difference in efficacy was apparent upon comparison of the various subtypes of these fasciocutaneous flaps. Not only did the fasciocutaneous flap provide salvage following failure of more conventional techniques, but it has even been proven in the proper circumstances to be a reliable initial alternative to free-flap or muscle-flap transpositions.

Dermatologic Surgical Procedures↗
PubMed1991

Skin recycling following neovascularization using the rat musculocutaneous flap model.

The recycling of a skin territory as part of a musculocutaneous flap despite prior division of existing musculocutaneous perforators or vice versa within an axial cutaneous flap using skin from a previous musculocutaneous flap may sometimes be done safely if an adequate time period has been allotted to permit sufficient neovascularization from adjacent tissues. In order to test this clinically observed phenomenon, a musculocutaneous flap model based on perforators from the rat rectus abdominis muscle was developed and observed to have complete reliability. Groups of five Sprague-Dawley rats each were sequentially utilized to prove that by a single week following creation of a rectus abdominis musculocutaneous flap adequate peripheral neovascularization would evolve to permit total viability of secondary axial epigastric cutaneous flaps incorporating the same skin that initially was the cutaneous portion of the muscle flap. The converse was also confirmed possible, again using sequential groups of five rats each, in that by 2 weeks the skin of an initial abdominal cutaneous flap could instead be safely transposed and nourished as part of a rectus abdominis musculocutaneous flap. The proposition concerning the reliable reuse of identical skin territories as part of disparate metachronous flap configurations appears to be valid.

Animals↗
PubMed1991

Local fasciocutaneous flap skin coverage for the dorsal foot and ankle.

Recalcitrant wounds of the distal leg and foot are notorious for requiring complex solutions even when deceptively small or benign in appearance. The simplicity of local flap options is always preferable, but is limited about the dorsal foot and ankle region. Inclusion of the well-defined deep fascia with the overlying integument in this area permits creation of local fasciocutaneous flaps that may be an important viable alternative. Over the past 6 years, 13 patients have had 15 such fasciocutaneous flaps for ankle or dorsal foot soft tissue reconstruction, with vascular ischemia being the most common etiology. Although four major complications occurred (27%), no limb amputation was a sequela as local wound care was satisfactory for eventual healing. Seven of these patients (54%) either declined or technically were not candidates for a complicated microvascular tissue transfer, which usually would have been preferable, but nevertheless all results proved satisfactory.

Adult↗
PubMed1990

Preliminary assessment of laser Doppler flowmetry for determining timing of division of the cross-finger flap.

The elapsed time before division of the cross-finger flap depends on adequate neovascularization from the recipient digit. Although subjective assessment of capillary filling in the flap after application of a tourniquet to the donor finger usually is accurate, on occasion, interpretation of observations may be equivocal. In these circumstances, noninvasive office measurement with use of the laser Doppler permits a sequential determination of relative flap perfusion. This objective data facilitates an appropriate clinical decision by the hand surgeon to ensure flap viability after pedicle division.

Fingers↗
PubMed1990

Polyurethane nipple prosthesis.

Long-term nipple projection remains the elusive ingredient for measuring the success of a nipple reconstruction. Augmentation of this projection without sacrifice of autogenous donor tissues may be achieved using a polyurethane-coated silicone gel implant affectionately and descriptively called the "gumdrop" nipple. Two patients who agreed to implantation with this device have each been observed over a one-year period with no loss of projection. The role of an internal nipple prosthesis, although perhaps of some value as a salvage procedure, appears to offer few advantages over other accepted methods of reconstruction that do not use any foreign body.

Adult↗
PubMed1990

Scrotal reconstruction following Fournier's gangrene using the medial thigh fasciocutaneous flap.

Scrotal reconstruction with adequate protection of the testicles remains the challenge following Fournier's gangrene. Early single-staged sensate flap coverage is ideal. This is readily accomplished using the medial thigh fasciocutaneous flap based on the longitudinal axiallty of the anteromedial thigh suprafascial plexus. Only a single lower extremity need be violated, and the ipsilateral gracilis muscle may be simultaneously independently elevated for closure of larger defects. Primary donor site closure obviates the need for skin grafts.

Aged↗
PubMed1990

External monitoring of vascularized jejunum transfers using laser Doppler flowmetry.

Any buried free tissue transfer presents a dilemma for postoperative monitoring, and the vascularized jejunum as used for head and neck reconstruction is no exception. Exteriorization of a small common segment of the jejunum in a sense permits direct visualization. Objective assessment may then simultaneously be possible with a harmless external probe sewn onto the serosa. The laser Doppler blood perfusion monitor as one such device provides a simple means for continuous analysis of the adequacy of the jejunal circulation. Intraperitoneal in situ monitoring of isolated island jejunal segments has shown significant, immediate alteration of flow regardless of whether the vein or artery has been occluded. The laser Doppler has also proved accurate after transfer in predicting impending flap failure even though peristalsis and serosal color appeared normal on direct inspection.

Humans↗
PubMed1990

The conjoint extensor digitorum brevis muscle and dorsalis pedis osteocutaneous island flap.

The privileged donor site of the foot is a well-recognized warehouse for spare parts particularly adaptable for composite tissue replacement of hand defects. Simultaneous microsurgical transfer of many of these parts is frequently performed. The ability to transfer these components on a common vascular leash as distinct yet dependent entities is another variation of this theme that enhances its flexibility. The extensor digitorum brevis muscle island and separate vascularized second metatarsal osteocutaneous flap represent one of many possible technical combinations of conjoined flaps based on the dorsalis pedis source vessel. The muscle portion of this flap provides any necessary soft tissue coverage. Sufficient dorsal foot skin is spared to allow primary closure of the foot, thereby minimizing morbidity in this notoriously difficult donor site.

Foot↗
PubMed1990

Miniplate washers for improving lag screw fixation.

Increased efficiency in using the lag screw principle for rigid fixation of bone, particularly for fragile cortical or soft cancellous grafts, is facilitated by dispersion of screw head compression forces with a biocompatible metallic washer. Although none is commercially available, such washers may be quickly fashioned from the residua of any adaptation miniplate in quantities as required.

Bone Plates↗
PubMed1990

A schema for local flap selection in the upper extremity: a hypothesis.

Whereas any contemplation suggesting routinization in a plastic surgery endeavor may engender abhorrence or bespeak heresy, some generalizations are essential at least as a foundation from which a logical divergence may proceed. Such an approach for the selection of preferable local flaps in wound coverage within the upper extremity can be developed based on available options as will be presented in schematic form to confirm this hypothesis.

Arm↗
PubMed1990

Distal lower leg local random fasciocutaneous flaps.

Significant open wounds of the distal third of the lower leg that require some form of vascularized flap have historically been covered with distant cross-leg flaps or more appropriately with microsurgical tissue transfers. The rediscovery of the "random" fasciocutaneous flap as a reliable single-stage option for proximal lower leg defects has been extended distally to allow an expedient alternative in lieu of these more complicated procedures. Over the past 7 years, 17 selected patients had closure of distal leg and ankle wounds with 19 local antegrade-oriented fasciocutaneous flaps. All eventually healed without serious sequelae, although 5 (26 percent) had minor complications, except for one case that could only be salvaged with a free-tissue transfer in order to prevent limb amputation. For small- or moderate-sized, uncontaminated injuries, this approach warrants consideration under appropriate circumstances as a simpler option that may permit satisfactory healing and avoids the known risks of microsurgical tissue transfers.

Aged↗
PubMed1990

Salvage of total knee arthroplasty with local fasciocutaneous flaps.

Six patients who had delayed healing of the wound after total knee replacement were treated by appropriate débridement and restoration of soft-tissue coverage with local fasciocutaneous flaps. This procedure was successful; deep infection and failure of the arthroplasty did not develop in any patient.

Aged↗
PubMed1989

In utero fetal surgery using a milliwatt carbon dioxide laser.

In utero surgery represents a future new frontier with unknown possibilities for medical intervention. Since the presently available microsurgery instruments are too cumbersome or indelicate, low-energy carbon dioxide lasers have been investigated as a tool that holds promise as a fetal scalpel and hemastatic device. Preliminary results demonstrate that continued investigation is necessary to limit the zone of tissue destruction in these most diminutive patients.

Animals↗