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Biomedical subjects

G G Hallock

Publications and source records attributed to G G Hallock.

At least 19 recordsLinked to original sources
PubMed1992

Feasibility of skin deepithelialization using the contact neodymium-yttrium-aluminum-garnet laser.

In a manner similar to laserbrasion, the carbon dioxide (CO2) laser has a proven role for expediting skin deepithelialization, which is an essential component of many reconstructive procedures. However, the contact Neodymium-Yttrium-Aluminum-Garnet (Nd:YAG) laser has many additional attributes such as tactile feedback and less plume that theoretically offer an advantage over the CO2 laser for this adjunctive maneuver. In rat experimental models and clinical applications, removal of the epidermis necessary for skin deepithelialization may indeed be achieved using a rounded probe for vaporization with the contact Nd:YAG laser. Unfortunately, the length of time necessary for skin deepithelialization with the Nd:YAG laser exceeded even conventional methods, such that this role with the present technology, although possible, is inefficient and impractical.

Aluminum Silicates↗
PubMed1992

Microsurgical repair of the parotid duct.

Because of its relatively small caliber lumen, traumatic injuries of the parotid duct appropriately lend themselves to microsurgical repair. With the evolution of more modern techniques and materials, inert nylon microsutures placed under magnification permit an ideal atraumatic anastomosis of the divided ends of the parotid duct. Such an exact approach may also obviate the need for long-term stenting across the site of repair, which remains a controversial issue.

Adult↗
PubMed1992

The random fasciocutaneous flap for upper extremity coverage.

Rapid and appropriate healing of any upper extremity wound is essential for preservation of normal hand function. If vascularized tissue must be used, local cutaneous flaps nourished by the multiple perforators to the fasciocutaneous plexus avoid the complexity of microsurgical tissue transfers or prolonged immobilization required for distant pedicled flaps. For small or moderate-sized defects, assuming that adequate adjacent deep fascia has remained intact, these simple, rapidly elevated, so-called random fasciocutaneous flaps deserve initial consideration, as demonstrated in all 11 cases in this reported series.

Adult↗
PubMed1992

Transient single-digit ectopic implantation.

Although immediate replantation of an amputated digit is always preferable, mitigating circumstances (such as a severe concomitant injury involving the appropriate recipient neurovascular structures) might preclude such an attempt altogether. However, if these local structures have the potential, following adequate debridement and/or other tissue transfer, to accept this digit later, than an alternative for transient storage for delayed replantation should be considered. The deep inferior epigastric vessels are a recognized convenient site that could provide temporary ectopic revascularization of such a solitary finger. An example of this approach for thumb preservation is presented, although amputation of the hand before performing the secondary transfer unfortunately proved prudent.

Abdomen↗
PubMed1992

Temporary tarsorrhaphy "zipper".

Reconstructive eyelid procedures on occasion justify the concomitant use of a temporary, reversible tarsorrhaphy to provide corneal protection. A dilemma ensues in the trauma patient when frequent neurological evaluations simultaneously requires examination of the pupils. To circumvent the inconvenience of repeated suturing of the eyelids as in an occlusive suture, a technique with the facility of the opening and closing of a zipper is reviewed that allows rapid removal and reestablishment of the desired temporary tarsorrhaphy.

Eyelids↗
PubMed1992

Zones of the lower transverse rectus abdominis musculocutaneous flap based on laser Doppler flowmetry.

Improvement in the reliability of the lower transverse rectus abdominis musculocutaneous flap for breast reconstruction using autogenous tissues has been predicated on a thorough analysis of the vascularization of this flap and methods for its preservation. The arbitrary division of the skin paddle into zones based on relative perfusion has simplified an appreciation of the underlying vascular anatomy. Laser Doppler flowmetry has been used to confirm these anatomical findings and establish a single system based on descending values of observed blood flow. Zone I has been assigned to that region overlying the ipsilateral and zone III the contralateral rectus sheath, whereas zone II corresponds to the ipsilateral and zone IV the contralateral superficial inferior epigastric territory.

Abdominal Muscles↗
PubMed1992

Assessment of TRAM flap perfusion using laser Doppler flowmetry: an adjunct to microvascular augmentation.

Any necrosis after reconstruction of the modified radical mastectomy defect using a superior epigastric based unipedicled lower transverse rectus abdominis myocutaneous flap should be unusual. Identification of the marginal flap at risk for this complication is important as this would permit immediate microvascular augmentation to enhance total survival. The dilemma, then, is how to define which flaps would benefit. We believe this is possible using laser Doppler flowmetry as a continuous, noninvasive, objective monitor of flap perfusion. Flow characteristics have been obtained in 16 consecutive transverse rectus abdominis myocutaneous flaps using the laser Doppler, where 2 were shown to have been in jeopardy for major flap loss. After appropriate microanastomoses as indicated, all flaps totally survived as predicted.

Abdominal Muscles↗
PubMed1992

Dorsal thoracic fasciocutaneous flap salvage of the failed transverse rectus abdominis musculocutaneous flap.

The pedicled lower transverse rectus abdominis musculocutaneous flap, now considered the standard for breast reconstruction using autologous tissues, still may be plagued occasionally by significant flap necrosis in spite of the best intentions. Rather than discarding the residual flap, it may suffice as an autologous implant if an additional source of tissue can be used for surface coverage. The dorsal thoracic fasciocutaneous free flap provides such a large, yet reasonably thin, skin territory that can uniformly cover the new breast, ultimately salvaging an acceptable result after a partially failed transverse rectus abdominis musculocutaneous flap.

Female↗
PubMed1992

Laser deepithelialization of the transverse rectus abdominis musculocutaneous flap.

Total or partial skin deepithelialization of the transverse rectus abdominis musculocutaneous (TRAM) flap is an integral component of this technique for achieving a successful breast reconstruction. In a manner similar to dermabrasion, the carbon dioxide laser in a defocused mode permits precise removal by vaporization of the epidermis and outer dermis. The extended application of this method for deepithelializing the TRAM flap is simple, rapid, and safe. Because a portion of the dermis always remains intact, another inherent advantage of this method is preservation of the subdermal vascular plexus that may be important for maintaining any precarious flap perfusion.

Abdominal Muscles↗
PubMed1992

Intrathoracic application of the transverse rectus abdominis musculocutaneous flap.

The use of extrathoracic muscles for intrathoracic transposition of healthy tissues for correction of intrathoracic pathology has many precedents. The lower transverse rectus abdominis musculocutaneous flap as elevated in a manner identical to that more commonly used for breast reconstruction may also serve that role especially for basilar thoracic defects if more traditional muscle flap options are unavailable. A unique case of intrathoracic transfer of a lower transverse rectus abdominis musculocutaneous flap for obliteration of a chronic empyema cavity is presented.

Abdominal Muscles↗
PubMed1992

Bipedicled fasciocutaneous flaps in the lower extremity.

It is well known that a bipedicled skin flap permits survival of longer flaps due to the secondary recruitment of vascularity. Inclusion of the deep fascia with such a flap, obeying the principles of the single-pedicled fasciocutaneous flap, provides even greater security for the immediate transposition of yet larger or riskier flaps without the need for delay maneuvers. This variation is especially valuable for the management of difficult wounds encountered in the lower extremity when no other local options may be available. Thirteen local bipedicled fasciocutaneous flaps including both vertical and horizontal orientations, without isolation of any discrete fascial perforators, have been successfully used for soft tissue coverage in the distal leg and ankle with only three (23%) minor complications as untoward sequelae. Another major advantage of this bipedicled version of the fasciocutaneous flap was that the inclusion of a distal pedicle simultaneously may be designed to prevent bone or tendon exposure at the donor site that otherwise frequently is a concern with a unipedicled flap.

Adolescent↗
PubMed1992

Prediction of nipple viability following reduction mammoplasty using laser Doppler flowmetry.

The assessment of viability of a pedicled nipple-areola complex after reduction mammoplasty frequently may be frustrating due to equivocal clinical signs of adequate blood flow. Although conversion to a composite graft is always a safe option, the aesthetic result may be inferior. An objective monitor might be beneficial to maximize the surgical outcome while minimizing the risk of nipple necrosis. Laser Doppler flowmetry provides a safe, simple, and noninvasive objective monitor that allows continuous intra-operative or postoperative evaluation of nipple perfusion. An evaluation of 31 nipples in 16 patients undergoing breast reduction based solely on the surgeon's judgment would have resulted in 9 false positive or negative results as compared with 3 using the laser Doppler. Four nipples that may otherwise have been converted to free grafts were instead preserved. However, conclusions from this data limit the laser Doppler as a valuable supplement, but not a replacement, for experienced clinical acumen.

Female↗
PubMed1992

The role of local fasciocutaneous flaps in total burn wound management.

The majority of acute burn wounds or delayed reconstructions are best managed simply with a skin graft. However, if vascularized tissue is mandatory, the local fasciocutaneous flap may have an important role in providing a single-stage technique for obtaining tissue nearly identical in color, texture, and consistency to that of the defect being restored. This review of 182 consecutive burn patients needing surgery found that they underwent 233 separate episodes for skin grafting. Appropriately, only a fraction of this number required some form of vascularized flap, with 14 patients having 21 local fasciocutaneous flaps. Six were elevated in previously skin-grafted regions, which is an advantage peculiar to this flap type. Three flaps (14 percent) suffered major complications requiring a second surgical intervention. Only six of all flaps were used for acute burn wounds, but two of the three complications accrued in this subset, with one directly attributable to wound infection. Since most flaps were required for either coverage or release of contractures about joints, it has been recommended that the initial surgical approach for treatment of the acute wound in these regions be altered to preserve the fascial plexus whenever possible to permit the use of this simple and expedient alternative if it is needed later.

Burns↗
PubMed1992

Critical threshold for tissue viability as determined by laser Doppler flowmetry.

As a noninvasive method for continuous evaluation of tissue perfusion, laser Doppler flowmetry fulfills many of the prerequisites of an ideal objective monitor. A critical threshold for insuring flap viability, however, has not been universally accepted. In this experimental design using pedicled epigastric flaps in rats, it was determined that if flow alterations in an otherwise healthy flap always exceeded 30% of the initial baseline value, consistent viability could be predicted. Although this relative critical index could be established, the variability of even intraspecies flow rates precluded defining any specific numerical index of flow that could always predict flap survival.

Animals↗
PubMed1991

Complications of the free-flap donor site from a community hospital perspective.

Techniques for achieving appropriate wound healing with minimal aesthetic or functional deformity of the microsurgical flap donor site are often assumed to be of minor importance or blatantly overlooked. Surprisingly, an analysis of 115 consecutive free-tissue transfers by a single surgeon within a community hospital setting, revealed an overall donor-site complication rate of 31 percent, with significant disability from major complications occurring in 10 percent of cases. Recognition of the projected morbidity of alternative donor sites therefore deserves scrutiny, with the same intensity as does consideration for flap selection, previously done solely to fulfill the requirements of the recipient site. While flap viability has previously been the criterion for success, the future dictates that morbidity at the donor site be an equally important consideration.

Hospitals, Community↗
PubMed1991

Intimal staining for visibility enhancement during microanastomoses.

Absolute perfection in microvascular surgery continues to be thwarted by technical inadequacies in construction of the microanastomosis. Occasionally this is a consequence of limited visualization or misidentification of the intima proper predisposing to thrombosis. At least in rats, we have demonstrated that intimal staining with clinically inert vital dyes has enhanced gross appreciation of the exact intimal location. This maneuver has simplified suture placement without evidence of any associated increased risk of anastomotic failure.

Anastomosis, Surgical↗
PubMed1991

Isle of palm and sole fillet flaps.

Extensive extremity injuries appropriately managed by immediate amputation may be compromised if retained soft tissues are inadequate to permit a simple wound closure. In usual circumstances, if the foot or hand from the soon-to-be-discarded part has not been violated and, by chance, remains viable through a major neurovascular pedicle, then a fillet of the sole or palm fashioned as a local island flap may be used for durable and potentially sensate stump coverage. Function preservation by salvaging maximal amputation stump length could then be achieved in lieu of more complex microsurgical techniques.

Adult↗