Search PubMed⌕ Search

Biomedical subjects

G G Hallock

Publications and source records attributed to G G Hallock.

At least 91 records · Page 5Linked to original sources
PubMed1994

Color duplex imaging for identifying perforators prior to pretransfer expansion of fasciocutaneous free flaps.

Pretransfer expansion of a fasciocutaneous free flap simultaneously creates a flap of large dimensions and allows primary closure to minimize donor site deformity. Although simple in concept, initial placement of the expander envelope must be done to ensure that the ultimate vascular integrity of the flap has not been compromised. This approach necessitates a precise knowledge of the dominant perforator to the flap and its location. Unfortunately, the perforators nourishing fasciocutaneous flaps are notorious for their variability. As a means to circumvent this potential obstacle, preoperative color duplex imaging was performed in 4 patients, who then underwent pre-expansion of a fasciocutaneous free flap. All perforators within the chosen donor flap territory were identified and measured to ascertain dominance. Preoperative mapping delineated safe regions that could be undermined for expander placement. At the time of ultimate free flap elevation, in vivo dissection of all perforators proved their caliber to be as predicted. No perforators had been violated by the expansion process. Concomitant linear closure of all donor sites after flap transfer obviated any need for skin grafts.

Adult↗
PubMed1994

Mutilating shredder/chipper hand injuries.

Outdoor recreational and vocational hand injuries occur with a predictable seasonal fluctuation and regional variation. An increasing demand in less urban areas for efficient yard and garden waste removal, combined with the availability of more affordable shredder/chipper machines, has increased their utilization. Potential hazards have been well recognized, but, not surprisingly, this behavior pattern has concomitantly introduced another characteristic syndrome of self-inflicted operator injury most prevalent in the fall and spring months. The seriousness of the possible upper extremity mutilation caused by these devices cannot be understated, as invariably, complex reconstruction modalities are essential to restore a useful hand.

Accidents, Home↗
PubMed1994

The Mitek Mini GII anchor introduced for tendon reinsertion in the hand.

The Mitek Mini GII anchor is showcased as a relatively new device that provides a rapid, simple method for bony reattachment; here, it is introduced for the fixation of flexor or extensor tendons at their insertion. Transosseous tunnels with limited visualization, pull-out sutures, and external devices can now be avoided if desired. Applications for soft-tissue fixation should in no way be limited to the small bones of the hand. Expense of the apparatus remains its only major drawback.

Adolescent↗
PubMed1994

Evaluation of fasciocutaneous perforators using color duplex imaging.

Technological improvements in conventional ultrasound, including color duplex imaging, have greatly facilitated the evaluation of vascular-related problems for virtually every specialty. Higher-frequency transducers now permit the scanning of superficial depths beneath the skin surface with high sensitivity for an analysis specific to the microcirculation. This attribute has already been recognized as a valuable tool for the preoperative mapping of musculocutaneous perforators. A logical extension of this capability would be for the localization and calibration of deep fascial perforators, which may have even greater clinical significance because anomalies at this level are more the rule rather than the the exception. Over the preceding 10-month period, all eight elective fasciocutaneous flaps performed in eight patients had initial scans using color duplex imaging to identify and calibrate all relevant cutaneous perforators. All fasciocutaneous flap subtypes were included. If feasible at the time of flap elevation, all identified perforators were dissected and measured. All were found at the exact site as marked preoperatively, and their diameter closely approximated that predicted. The occasional unanticipated presence in vivo of minor perforators suggests that color duplex imaging may not be reliable for fascial perforators less than 0.5 mm in diameter. Since perforator caliber qualitatively is a major determinant of flow, color duplex imaging can then objectively establish a hierarchy of the importance of perforators in a given region. From such data, the definition of new and more reliable fasciocutaneous flap donor territories should be forthcoming.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1994

An adult with juvenile hyaline fibromatosis of the foot.

An unusual consideration in the differential diagnosis of benign, solid tumors of the foot is juvenile hyaline fibromatosis, which only superficially resembles the better known myofibromatosis. The onset of the typical cutaneous lesions of this affliction, more frequently found in the head, trunk, or upper extremity, usually begins in childhood, with a progressive increase in their size and number. No cure is known, but early surgical excision of smaller lesions will minimize bony erosion and skin ulceration that otherwise risks toe amputation, thereby preserving function and a reasonable esthetic result. Incomplete excisions are doomed to recurrence, but, fortunately, this normally is a slowly growing tumor.

Adult↗
PubMed1993

The cephalic vein in microsurgery.

A working knowledge of the venous anatomy is seldom emphasized but is an essential element in all microvascular procedures. The cephalic vein has been chosen here to serve as a model, since it is an important source for both afferent and efferent flow for flap transfers as well as in limb replantations. The better known, lower extremity superficial veins, especially as a source for long vein grafts, are not necessarily the best option. The cephalic vein represents the most versatile of the large superficial veins of the upper extremity and has numerous roles in microsurgery other than as a viable alternative for vein grafts.

Arm↗
PubMed1993

Cylindrical nipple reconstruction using an H flap.

Just as a successful breast reconstruction cannot be achieved using a solitary method for every patient, no single surgical technique is a panacea for the final stage of nipple creation. For breast mounds with a thin subcutaneous layer, as commonly associated with the implanted breast, local flaps using a central subcutaneous core have strong advocates. The H-shaped local flap introduced here is a variant of the latter where large, well-vascularized side tabs provide adequate projection with minimal risk for flap slough. More importantly, a cylindrical shape geometrically identical to the norm avoids the bulbous appearance frequently resulting from many of the other central-core flap designs.

Female↗
PubMed1993

Futility of muscle flaps for self-inflicted wounds.

Unacceptable forms of self-mutilation usually are resistant to surgical intervention and have a basis in psychopathology. Establishing this diagnosis may be as difficult as is the treatment, frequently involving a prolonged process of exclusion of other known disease entities. Management of these chronic self-inflicted wounds demands flexibility by the surgeon who must be aware of this possibility and willing to deviate from the normal approach to wound healing. Simplicity is of paramount importance. The use of vascularized tissues and, in particular, the sacrifice of scarce muscle flaps probably is unwarranted except as a last resort because these wounds nevertheless remain recalcitrant to permanent healing. Instead, a nonconfrontational approach with long-term psychotherapy should be a major part of the initial therapy with surgery considered only important in an adjunctive role.

Adolescent↗
PubMed1993

The ontogenetic transition of collagen deposition in rat skin.

Minimizing the morbidity of in utero surgery or, perhaps more important, capturing the unique characteristics of scarless remodeling, as is the fetal response to injury, demands better elucidation of the observed variations from adults in whom the normal progression of wound healing leads to fibrosis. Species-dependent fetal phlogistic responses and wound scar formation represent a temporal continuum before the onset of adult patterns. We have analyzed skin collagen synthesis and content in Sprague-Dawley rats as one possible factor in this evolution showing that the fetal characteristics of a high percentage of type III collagen relative to type I and low total collagen content are maintained as long as the first 10 to 15 days postpartum. Although extrapolation of such a crucial "golden period" to justify the delay of human surgical procedures while still capturing the benefits of the fetal milieu remains speculative, anecdotal observations of minimal scar formation lend some credibility for performing less invasive maneuvers in the neonate.

Animals↗
PubMed1993

The triceps muscle flap for axillary contracture release.

Previously overlooked, the concept of a triceps muscle flap has been recently proven valid. By using only the long head portion, necessary function preservation may be achieved. A distinct proximal neurovascular source to this component alone allows an axis of rotation at the level of the teres major muscle. This permits transposition either in an anterior or posterior direction as a local muscle flap that has usefulness, albeit in a secondary role, for axillary reconstruction such as commonly required as a sequela to burn contracture.

Adolescent↗
PubMed1993

Myonecrosis as a sequela of calf implants.

Calf augmentation using alloplastic implants primarily is intended to enhance body contour. Usually this is a safe and efficacious procedure. However, in this unique report, significant myonecrosis occurred as a direct consequence of calf implantation, which resulted in a residual functional disability as well as aesthetic deformity. An awareness of the potential for a similar catastrophe hopefully will mitigate against future overzealous attempts at augmentation.

Adult↗
PubMed1993

Increased sensitivity in objective monitoring of tissue expansion.

The end point for incremental filling of any tissue expander normally may reliably be assessed using subjective parameters, especially pain, as a guideline. However, in unusual circumstances, such as within denervated areas, the presence of marginal skin circulation, or if rapid expansion is required, an objective monitor may be beneficial to ensure safer expansion. We have previously examined the role of serial measurement of transcutaneous oxygen in this regard. In an effort to refine this sometimes cumbersome approach, a comparison using laser Doppler flowmetry as well has been undertaken in 13 consecutive patients. Both monitoring devices demonstrated a progressive impediment to blood flow with increased expansion. At the pain threshold, both techniques recorded values consistent with adequate skin circulation, thereby proving in general the relative safety of subjective evaluation during the usual course of tissue expansion. Greater sensitivity was noted for the laser Doppler as a monitor, though, via the recording of earlier changes in flow characteristics and more rapid identification of critical thresholds for nonviability. From a more practical standpoint, immediate application without a period for equilibration is another major asset of laser Doppler flowmetry as a system for objective monitoring.

Adolescent↗
PubMed1993

Salvage by tattooing of areolar complications following breast reduction.

Even partial areolar loss following breast reduction must be considered an aesthetic disaster for which there are few surgical options for correction. Tattooing, as directly borrowed from postmastectomy techniques for nipple-areola creation, permits reconstitution of a reasonable facsimile of the areola. Discoloration or loss of nipple contour as may also occur in composite nipple-areola grafts may be enhanced and/or an illusion of nipple projection achieved by appropriate regional micropigmentation. Tattooing provides another simple method that can be repeated with virtually no morbidity for salvage of an unacceptable result following breast reduction.

Female↗
PubMed1993

The surgical anatomy of the principal nutrient vessel of the tibia.

Large segmental long-bone defects deserve consideration for reconstruction by vascularized, straight, high-density cortical bone grafts of comparable diameter. If available, the tibial diaphysis would be an option superior to the fibula, since the latter has known limitations when a large size discrepancy exists at the recipient site. However, the former choice is unrealistic except in the most unusual circumstances, since the tibia is a nonexpandable bone required for weight bearing. In anticipation of just such a unique opportunity, we have investigated the surgical anatomy of the principal nutrient vessel of the shaft of the tibia in 53 fresh lower limb specimens. Classical descriptions of the pertinent vascular anatomy of the tibial shaft are inadequate, since the origin of its principal nutrient vessel actually may be from the popliteal bifurcation or anterior or posterior tibial vessels. In every dissection at least a single artery and vein of large caliber (both exceeding 1.5 mm in diameter in 85 percent of cadavers) were discovered entering a nutrient foramen, usually at the upper third of the tibia. Lead oxide injection studies of the nutrient artery alone in nine cadavers demonstrated no contiguous muscle or cutaneous communications. The large size of these nutrient vessels would simplify ipsilateral pedicled transfers of an autologous tibial shaft as well as facilitate microanastomoses for its distant transfer to other humeral, femoral, or contralateral tibial defects as in a salvage replantation. Once immunologic barriers have been conquered, these data should have even greater practical clinical significance for the use of vascularized tibial allografts for substitution in lieu of autogenous fibula or other conventional bone donor sites.

Bone Transplantation↗
PubMed1993

Relative donor-site morbidity of muscle and fascial flaps.

Accusations of excessive donor-site morbidity as an unavoidable sequela of fasciocutaneous flaps has negatively prejudiced this option for coverage of adjacent defects such that a muscle flap, if available, would instead be preferable even at the risk of loss of marginally expendable function. Our entire experience with 147 juxtaposed muscle-type and 122 fascia-type flaps was analyzed to confirm instead that actual donor-site morbidity was extremely uncommon for either type. Overall, there were 20 (14 percent) complications of the donor site of muscle flaps and 17 (14 percent) for fascial flaps, with only 4 (3 percent) major complications in each group. This almost minuscule incidence of major morbidity was about five times less than the rate of major complications involving the flaps themselves (14 percent for muscle and 15 percent for fascial flaps). Unless aesthetic considerations are of paramount importance, at least from a functional standpoint, no difference in donor-site complications could be discerned between these two disparate flap types. However, the skin-grafted donor site of the fasciocutaneous flap results in a significant cosmetic disadvantage similar to that of a large musculocutaneous flap.

Adult↗
PubMed1993

Comparison of the contact neodymium:YAG and carbon dioxide lasers for skin deepithelialization.

The application of laserbrasion by the carbon dioxide (CO2) laser for skin deepithelialization previously has been proven efficacious in numerous clinical experiences. This study in adult Sprague-Dawley rats was designed to compare those known effects of the CO2 laser with the contact neodymium:yttrium-aluminum-garnet (Nd:YAG) laser for skin deepithelialization, since tactile feedback from the handpiece of the latter is a theoretical advantage. This proved that although the contact Nd:YAG laser does have the capability to achieve skin deepithelialization, when compared with more conventional methods, it is laboriously inefficient and therefore at present impractical.

Animals↗