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Biomedical subjects

G G Hallock

Publications and source records attributed to G G Hallock.

At least 37 records · Page 2Linked to original sources
PubMed1999

Consideration of the UltraPulse carbon dioxide laser as a tool for skin deepithelialization.

Laserbrasion is essentially skin deepithelialization. The continuous-wave carbon dioxide (CO2) laser has a long history during which this capability to ablate the epidermis has been used in multiple clinical applications. The "improved" UltraPulse CO2 laser has been advocated as a safer method, primarily for skin resurfacing. The authors show in Sprague-Dawley rats by gross and histological examination that the UltraPulse CO2 laser can also be used effectively to achieve skin deepithelialization, with efficacy in clinical simulations without untoward effects on wound healing. The advantage of the UltraPulse CO2 laser appears to be less destruction to surrounding tissues.

Animals↗
PubMed1999

An endoscopic technique for decompressive fasciotomy.

A guiding principle of minimally invasive techniques in plastic surgery is improvement of the aesthetic outcome, usually by reducing morbidity from postsurgical scarring. The elimination or reduction of scars has already been so achieved during elevation of fascial flaps and for the harvest of fascial grafts. A natural extension of this endoscopic experience is decompressive fasciotomy, which has now been performed successfully in the upper extremity. Using endoscopic guidance, this is actually a simple, rapid, and safe procedure with minimal morbidity, and should also be apropos for the lower extremity, where compartment syndromes are a more common malady.

Adult↗
PubMed1999

Secondary expansion of a replanted scalp salvaged by an intrinsic arteriovenous shunt.

1. Although scalping injuries reported in most large series rarely involve young children, partial scalp replantation, even in a 2-year-old boy after a dog-bite avulsion, should also be warranted. However, technical difficulties because of the diminutive vasculature can be expected. 2. Unconventional methods for reestablishing inflow or outflow for the replanted scalp may become the only practical alternative and must not be overlooked. In this case, an arteriovenous shunt between the frontal branch of the superficial temporal artery within the amputated part itself to a more distal scalp vein at the superior edge of the fragment allowed high-output flow to maintain patency after recurrent thromboses of the conventional superficial temporal arterial anastomosis. This fistula was assumed to be the major contributor to nutrient flow of the remaining scalp, as the parietal branch was truncated along the margin of the avulsion. 3. Delayed tissue expansion is also an option. In this case, delayed expansion of the replanted scalp that survived allowed elimination of the skin grafts needed to cover areas where necrosis ensued, restoration of the anterior hairline, and resulted in a more normal appearance.

Animals↗
PubMed1999

Minimally invasive harvest of the gracilis muscle.

Acceptance of minimally invasive plastic surgery has been predicated on decreasing morbidity while maintaining the quality and costs of outcomes. The major patient complaint about the gracilis muscle donor site has almost solely been related to the length of the thigh scar, and thus would appear to be an ideal indication for outcome improvement using minimally invasive techniques. A method of endoscopically assisted gracilis muscle harvest, therefore, was developed, starting with a transverse incision just proximal to the knee to identify the gracilis tendon. This endoscopic port allows retrograde subfascial dissection of the muscle and precise identification of its anatomic course, whereupon a small proximal medial thigh incision can be made secondarily for direct access to the vascular pedicle. This variation has now been used successfully in 10 patients. The mean proximal thigh scar length was 8.30 +/- 0.74 (SD) cm, and total surgical scars measured 11.84 +/- 0.95 cm, compared with 27.73 +/- 9.55 cm for 16 patients for whom an open method had been used. This diminished scar length was a statistically significant improvement (p < 0.05), verifying the value of the surgical endoscope as an adjunct for harvest of the gracilis muscle as a free flap.

Endoscopy↗
PubMed1999

The anatomy of the extended peroneal venous system.

The fibula has deservedly become a workhorse flap for vascularized bone grafts. As with most flaps, much is known regarding idiosyncrasies of its arterial supply, and the corresponding venous system has generally been assumed to be comparable. Because this donor site has become increasingly versatile, a detailed anatomic study that would verify this latter assertion should be important. Therefore, venous mapping specifically of the peroneal venae comitantes was completed in 29 fresh lower limbs. In every specimen, paired venae comitantes of large caliber indeed paralleled the course of the peroneal artery. All were of quality satisfactory for microanastomoses, which should provide reassurance that preoperative evaluation of the peroneal venous system is not routinely indicated. However, anatomic variations proved to be the norm. The two venae comitantes did not necessarily coalesce into a single common peroneal vein [6 of 29 (21 percent)]. Usually, the lateral peroneal vein was the larger and continued proximally either alone (17 percent) or as the common peroneal vein (66 percent) to form the lateral tibioperoneal vena comitans. Thus, the venous pedicle of a fibula flap could be lengthened up to its confluence with the popliteal vein, a maneuver that potentially could obviate the need for a vein graft at least on the venous side. Although anomalies of the peroneal artery could preclude use of the fibula altogether, there appeared to be no such contraindications from a venous standpoint, despite the fact that the venous anatomy was unique in every individual. Some important similarities in patterns, though, do exist. For example, a common peroneal vein was formed by the juncture of the lateral peroneal vein and some combination of branches joining the lateral posterior tibial vein and medial peroneal vein in 63 percent of all limbs. Because exceptions are the rule, the choice of donor vein and venous pedicle length best remains an intraoperative decision dependent on the presenting anatomy.

Arteries↗
PubMed1999

A systematic approach for improvement of the donor sites of fasciocutaneous flaps.

Fasciocutaneous flaps as a group have been maligned more often for fear of potential donor-site morbidity than any concern for reliability. Typically, this is related to limitations imposed by the skin graft necessary to close most such donor sites, as admittedly has been required for the majority (52 percent) of our 313 flaps over the past 2 decades. Nevertheless, 48 percent did not require skin grafts, reflecting the adoption of strategies that evolved to minimize this shortcoming. These included use of fascia-only flaps, primary closure with small composite flaps, direct closure possible by use of rotation or advancement flaps or a second flap, or a delayed closure utilizing either pretransfer or posttransfer tissue expansion. Donor-site complications were actually fewest when a skin graft or primary closure was possible and occurred at the same rate regardless of body region. However, because the skin-grafted donor site was always a cosmetic compromise, a systematic approach to circumvent its use whenever possible is emphasized as a valuable tool to enhance the role of fasciocutaneous flaps as a vascularized flap alternative.

Arthroplasty, Replacement, Knee↗
PubMed1999

The cosmetic split-thickness skin graft donor site.

Any split-thickness skin graft donor site is obvious to some degree because of pigment alterations and, at the worst, it can develop hypertrophic scarring. A predictably superior aesthetic result is possible if this site is converted to a full-thickness defect followed by primary closure, because a linear scar is the only residuum. Using a modified tumescent technique, the groin can also be readily used as a split-thickness donor site if a thin graft is preferred; it captures the attributes of an ideal donor site in which pain is diminished, healing rapid, and the scar inconspicuous, just as when it is used as a full-thickness skin graft donor site.

Groin↗
PubMed1999

Deepithelialization prior to onlay grafting using the UltraPulse carbon dioxide laser.

When used in a defoeused mode, the UltraPulse carbon dioxide laser causes skin vaporization at a subepidermal level with minimal surrounding thermal destruction, allowing early reepithelialization from retained skin appendages. This attribute is of paramount importance if only skin resurfacing is desired. However, because the effect essentially is total removal of the epidermis, such a sequela can also be used advantageously to prepare a vascularized dermal bed prior to onlay of composite grafts or secondary overgrafting. This skin deepithelialization can be achieved in a bloodless field, permitting constant visualization of the depth of penetration, and an integrated computerized pattern generator scanner allows rapid, precise, and consistent desurfacing to the desired level. This preliminary investigation demonstrates that successful overgrafting is possible on a viable dermal plane exposed by the UltraPulse carbon dioxide laser, as another example of its role in skin deepithelialization.

Dermatologic Surgical Procedures↗
PubMed1998

Multiple, synchronous ipsilateral soleus muscle flaps, including the Achilles' "wraparound" flap.

Versatility of the soleus muscle beyond its traditional role for the middle third of the leg is often overlooked. Substantial muscle bulk frequently extends even to the calcaneus, although this is quite variable. Its distal reach as a muscle flap then may potentially include encircling the Achilles' tendon itself as a local "wraparound" flap in an area otherwise notorious for requiring the complexity of a free tissue transfer. Since this maneuver only envelops the Achilles' tendon by stretching its own inserting soleus muscle, no muscle dissection per se is required, and nutrition from minor pedicles is sustained. Therefore, concomitant proximally based hemisoleus flaps can be utilized simultaneously and safely for more conventional coverage of midtibial defects. In this fashion, multiple, independent local flaps from a single soleus muscle can achieve coverage of disparate leg wounds, while sacrificing a minimum of donor site function.

Achilles Tendon↗
PubMed1998

An endoscopic subcutaneous dissector for obtaining vein grafts.

Recent improvements in internal mechanical retractors have resulted in a commercially available endoscopic subcutaneous dissector that has an inverted pistol grip for ease of retraction, an end-mounted endoscope channel, and a distal, translucent spoon-shaped shield that maintains the optical cavity. This provides an effective reach that is valuable for the minimally invasive harvest of any long, narrow structure--the greater saphenous vein in particular--as shown in this preliminary study with 2 patients. Such extracted vein grafts taken grossly from above and below the knee appear normal. Long-term histological changes and rates of conduit patency are still unknown. The limited-access incisions necessary for this endoscopic vein harvest definitely are smaller, and can be oriented transversely to minimize further the disfigurement from any resulting scar when compared with traditional methods.

Endoscopes↗
PubMed1998

Prospective study of the accuracy of the surgeon's diagnosis in 2000 excised skin tumors.

Expeditious yet efficacious removal of skin tumors is a common responsibility for the plastic surgeon. The need to minimize potential risks for mortality or morbidity from undue or excessive surgical resections and to control costs by avoiding unnecessary procedures behooves us to make a precise clinical diagnosis preceding any decision even for such "minor" surgery. Just how accurate these decisions can be expected to be for a typical surgical practice was scrutinized by means of this prospective 4-year study involving the resection of 2058 skin lesions. Each lesion was initially assigned a clinical diagnosis after a brief gross examination and then compared with the pathology report, which was always considered to be the correct answer. Within these parameters, only 65 percent of all tumors were identified correctly preoperatively. Two-thirds of all lesions were benign. Three-quarters of benign lesions were as assumed, and 92 percent of all presumed benign lesions were benign even if incorrectly identified initially, whereas fortunately only 3 percent proved to be malignant. On the other hand, only three-fifths of malignant lesions were identified correctly clinically, yet only 11 percent were benign, implying that most such lesions properly deserved excision anyway. Therefore, approximately 90 percent of all lesions whether benign or malignant were removed appropriately without compromising the patient, but to expect a clinical acumen of 100 percent in this setting may not be realistic. The accuracy of the surgeon in identifying lesions as probably benign was certainly high enough that cost-containment mechanisms designed to deny authorization for their removal probably would be justifiable and difficult to appeal. Any suspicious or equivocal lesions still will require mandatory intervention despite such constraints, because often only histologic examination will allow a definitive diagnosis.

Basal Cell Carcinoma↗
PubMed1998

Fate of the TRAM flap after abdominoplasty in a rat model.

During a classical abdominoplasty, all musculocutaneous perforators from the deep inferior epigastric vessels are normally divided. Even if somehow neovascularization could relink the abdominal skin and rectus abdominis muscles, reestablishing these same discrete perforators would be unlikely because of the barrier effect of the abdominal wall fascia. Therefore, a lower transverse rectus abdominis musculocutaneous (TRAM) flap intuitively should not regain sufficient vascularity for viability after a prior abdominoplasty, and a history of the latter should be expected to be a major contraindication for this procedure. Nevertheless, anecdotal observations of successful lower TRAM flaps following abdominoplasty seem to contradict our basic principles, which may need better further elucidation. Consequently, this two-stage study in Sprague-Dawley rats was undertaken, initially performing an abdominoplasty in all rats. This was followed 1 or 10 months later by the creation of an unipedicled superiorly based TRAM flap that incorporated virtually all of the abdominal skin. From our identical historical TRAM flap control (n = 5) except without prior abdominoplasty, 72.8 +/- 12.83 percent of this area survived. TRAM flaps raised 1 month after the abdominoplasty (n = 6) had 2.2 +/- 3.4 percent or essentially no viability. Unexpectedly, the long-term group (n = 7) demonstrated 13.7 +/- 10.0 percent viability, ranging from 0 to 30 percent. Both groups of TRAM flaps after abdominoplasty had a flap survival area significantly less than that of the control by two-tailed group t test (p < 0.001), and that of the long-term group area was significantly greater than that of the short-term (p = 0.022). Lead oxide studies 10 months after abdominoplasty revealed no irrefutable evidence of the reestablishment of rectus abdominis perforators to the integument, although obviously some reconnections had formed at the microcirculatory level to partially revascularize some flaps. The range of viability of the long-term rat TRAM flaps documented that for the majority, surviving surface area was minuscule even following a delay equivalent to a human decade after abdominoplasty (1 rat month - 1.1 human years), yet rarely sufficient revascularization did indeed occur, which could explain the prior unusual clinical successes. However, the basic principle that a TRAM flap raised following a classical abdominoplasty at any time would be a risky maneuver seems to still be a valid concept.

Abdominal Muscles↗
PubMed1997

Macrovascular surgery and the microsurgeon.

The improvement of success rates in microsurgery can be attributed as much to better technical skills, as to the more frequent selection of donor or recipient sites with consistent, larger-caliber vessels. Often, these vessels may be larger than major limb source vessels, and anastomoses using loupes can then be successful, even without requiring an operating microscope Thus, distinguishing our capabilities from the domain of the general vascular surgeon, who traditionally deals only with the ravages of disease or trauma to such large vessels, has become blurred. For some free-tissue transfers, and especially limb replantations, perhaps it would be appropriate for the microsurgeon sometimes to enter the realm of the macrovascular surgeon for enhancement of the overall outcome. A review of our 202 free flaps and pediatric limb revascularizations has validated this opinion, as significant portions in 19 of these cases required unequivocal macrovascular surgery. These included vein-graft bypasses (9) of major segmental arterial defects of limbs (that incidentally improved collateral circulation, although intended primarily to simplify arterial inflow to a free flap simultaneously needed to cover a concomitant soft-tissue defect). Similarly, arterial grafts as part of a "flow-through" free flap (3) were used for immediate coverage and concurrent limb revascularization. Finally, two toddlers who sustained disruption of named leg vessels had microsurgical repair after referral from the vascular service; they believed we were better able to deal with such diminutive vasculature. These observations are not intended as evidence that vascular surgery may be better performed by the microsurgeon; rather, that the best results of microsurgery often will incorporate technical aspects usually considered as macrovascular surgery.

Adult↗
PubMed1997

Permutations of combined free flaps using the subscapular system.

Over five dozen permutations of free-flap combinations based on the subscapular system are possible. Although this has been the most common single flap donor site in the author's overall experience (38.5 percent), the use of a combined flap has been required in only seven cases, representing only 10 percent of all free flaps selected from this region, indeed implying that their indications are limited. When muscle flaps per se were specifically desired, the latissimus dorsi and serratus anterior muscles could be simultaneously transferred, while requiring only a single microanastomosis to their common subscapular pedicle. Additional advantages of using this most common form, or with other combined flaps, are not only augmentation of available surface area for wound coverage, but also disparate sites can be closed individually: microanastomoses are easily protected by the second flap; circumferential gliding surfaces are provided to minimize tendon adhesions; and dynamic restoration of multiple paralyzed muscles is achieved, while violating but a single donor site.

Adult↗
PubMed1997

Repair of an untreated cleft palate in an adult using a prefabricated radial forearm flap.

The untreated isolated cleft of the palate in an adult is rarely encountered today. It can also be difficult to close using conventional techniques because of the disparity between the extremely wide cleft and the paucity of available local tissues. One possible solution is a thin radial forearm free flap. If used as a bilaminar flap prefabricated by placement of a skin graft on its fascial undersurface at an initial stage, both the requisite nasal lining and oral mucosa can simultaneously be introduced to close the palate. This maneuver may reduce the potential for late flap contracture and avoids cumbersome methods for immobilizing a skin graft if this were attempted after flap transfer.

Adult↗
PubMed1997

The role of local fascial flaps as an adjunct to free flaps.

Local fascial flaps independently are a versatile option, reliable when properly designed, and technically simple to execute especially when compared to microsurgical tissue transfers. Although free flaps continue to be the method of choice to repair major distal extremity defects, for smaller wounds it could be preferable to use a local fascial flap instead. In reviewing the 194 local fascial/fasciocutaneous flaps used by us since 1982, 46 were specifically used in lieu of a free flap that had been initially considered. Only two of these failed to achieve their objective, indeed then requiring salvage by a free flap. In addition, a local fascial flap was concurrently advantageous as a second flap on 17 occasions to simplify coverage of the microanastomoses, to facilitate closure of the free flap donor site, or as the backup method for a failed free flap with limb preservation. Therefore, 32.5% (63 of 194) of all of our local fascial flaps were either used as a substitute for or improved the overall success rate as an integral part of our microsurgical experience during this same time period.

Anastomosis, Surgical↗