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Biomedical subjects

G G Hallock

Publications and source records attributed to G G Hallock.

At least 55 records · Page 3Linked to original sources
PubMed1997

Adipofascial flap harvest using endoscopic assistance.

Minimally invasive plastic surgery has expanded beyond the original confines of aesthetic applications to encompass all our endeavors in an attempt to restrict the size of surgical scars, limit postoperative discomfort, and hasten recovery of function. This evolution has already delineated methods to raise our workhorse muscle flaps and has negated the risks of laparotomy for various visceral flaps. It is then only a logical progression to use these endoscopic techniques to harvest fascial flaps so as to avoid the notorious donor site morbidity of the fasciocutaneous flap, which has certainly hindered the rapid acceptance of these otherwise valuable flaps. Endoscopic-facilitated elevation of a local adipofascial flap is described for which little or no additional skin incisions need ever be made.

Accidents, Occupational↗
PubMed1997

The role of pedicled or free fibular grafts in knee arthrodesis.

Arthrodesis of the knee can be facilitated by using a vascularized fibular graft if a large skeletal defect encompasses the knee joint or if conventional attempts at fusion have been unsuccessful. Solitary or double fibular grafts incorporated as part of a free tissue transfer or an ipsilateral pedicled flap rotated proximally about the knee are acceptable alternatives. Either version requires the technical expertise well known to reconstructive microsurgeons, as emphasized in this review, as a familiarity with this donor site and the nuances of graft elevation are essential for success.

Adult↗
PubMed1997

Mechanisms of burn injury secondary to airbag deployment.

The efficacy of airbags as a vital, supplemental restraining device has been proven by their role in diminishing the rate of fatalities and severity of injury in motor vehicle crashes. Unfortunately, as with any developing technology, deployment of the airbag itself has caused some new problems. Most airbag-related injuries are minor and, surprisingly, more than 5% are burns typically involving the upper extremity or head and neck. These are a result of the high temperature of the gases released during inflation or of direct contact with the corrosive alkaline plume created as a combustion by-product. Fortunately, these are superficial burns that usually require only expectant treatment, but a high degree of suspicion in these circumstances is needed to make the proper diagnosis.

Aged↗
PubMed1997

Nonoperative estimation of the soleus musculotendinous junction using magnetic resonance imaging.

Although it is recognized as the muscle flap of choice for middle-third defects of the lower limb, the capability for even more distal transposition of the soleus muscle remains controversial. Such reach depends directly on the site of insertion of the muscle and previously has not been assessed convincingly without surgical intervention. Magnetic resonance imaging (MRI) may be a noninvasive alternative for determining the distal extent of the musculotendinous junction of the soleus muscle. In our last four patients, preoperative MRI scans were obtained prior to an elective soleus muscle transfer. The distance from the ankle joint to the most distal site of the soleus insertion was measured on the MRI scan and compared with the actual intraoperative measurement, which had a significant correlation (r = 0.98, p = 0.019). A retrospective review of 42 other sagittal ankle MRI scans predicted the mean of this distance to be 1.92 +/- 1.23 cm (range -0.4 to 4.5 cm), compared with gross anatomic dissections in 30 unrelated fresh cadavers, where this was 4.06 +/- 3.11 cm (range -0.7 to 12.5 cm). These additional data are pertinent because they reinforce recognition of the great variation in soleus anatomy, which would limit clinical applications for the distal third of the leg only for those individuals with very distal insertions. The MRI scan can reliably identify the soleus muscle and provides a nonoperative method for evaluation of potential feasibility for its use as a local muscle flap for distal lower extremity defects.

Ankle↗
PubMed1997

Partial failure of a free flap salvaged by using the surviving portion as a "bridge" flap for revascularizing a second free flap.

Partial failure of a free flap can create an unusual dilemma, as guidelines suggesting appropriate further intervention are not well defined. The increased complexity of a second free flap attempt is not necessarily contraindicated, but must be minimized if the same fate as the first is to be avoided. For the unique circumstance where the initial failed flap contained a vascular flow-through, the most distal patent vessels can then secondarily serve in an expeditious manner as the recipient vessels for the second or salvage free flap. The efficacy of this concept has been here validated after limited necrosis occurred in the distal portion of a radial forearm free flap. Following the requisite debridement, the residual flap still maintained a satisfactory arterial and venous flowthrough as a "bridge flap" that supported the attachment of a gracilis muscle free flap, and both flaps in turn preserved a sensate transtarsal amputation stump.

Amputation, Surgical↗
PubMed1997

Clinical scrutiny of the de facto superiority of proximally versus distally based fasciocutaneous flaps.

Just as the dogma that skin flap survival depends on rigid length-to-width ratios has been refuted as a consequence of advances in understanding the anatomical basis of the cutaneous circulation, the generalization that distally based flaps are inherently inferior to proximally based flaps also deserves to be challenged. All else being equal, the truly critical factor for flap viability in either case is the nature of their intrinsic blood supply rather than any arbitrary configuration or orientation. Previous laboratory evidence has proved this fact and is now further validated by a clinical experience with 194 local fascia flaps in 174 patients. There was a 22.2 percent overall incidence of complications, but no statistically significant difference in this rate was observed whether the flap was distally based (18.8 percent of 16 flaps) or proximally based (23.5 percent of 162 flaps) (p = 0.669). Major complications, usually a failure of the intended coverage, actually were more common for proximally based flaps (12.9 percent) than those distally based (6.3 percent), although not statistically different (p = 0.436). Bipedicled fasciocutaneous flaps, which should have had augmented perfusion from their dual sources of inflow, sustained complications in 12.5 percent of 16 flaps. Although none was classified as a major problem, again no difference was apparent when compared with proximally based (Pprox = 0.316) or distally based (pdis = 0.626) flaps. Some caution is prudent in interpreting these retrospective data, not because of an admitted bias for more frequent selection of proximally based flaps, but because the choice for any of these local fasciocutaneous flap always followed a careful assessment of the status of the fascial plexus adjacent to any defect. Audible or color Doppler ultrasound localization of available cutaneous perforators can predetermine the feasibility of any option, thereby ensuring a reasonable success rate regardless of pedicle orientation.

Anastomosis, Surgical↗
PubMed1996

Use of a micropunch for arteriotomy in end-to-side anastomosis.

A micropunch can mechanically create a precise, clean microarteriotomy that is a simple and perhaps more accurate method, especially in atherosclerotic vessels where plaque or the risk of intimal dissection may sometimes interfere with conventional incision or excision techniques. A 1.5-mm. prototype micropunch was tested in seven Sprague-Dawley rats to create;l an end-to-side femoral vein to artery fistula, with a traditional traction suture method used on the contralateral side as a control. All anastomoses were patent immediately and at 2 weeks, implying no compromise, even in small vessels, by using a micropunch. However, the technique had to be modified, as the 1.5-mm anvil could not be inserted directly into the vessel lumen because of the small size of the rat femoral artery. This indicates a significant limitation of this device for use in vessels with an internal diameter less than that of the chosen anvil size.

Anastomosis, Surgical↗
PubMed1996

Liability of recipient vessels distal to the zone of injury when used for extremity free flaps.

The selection of recipient vessels distal to an extremity defect can be tantalizing option, offering the potential advantage of rapid accessibility to relatively large vessels that, in turn, would simplify revascularization of any desired microsurgical tissue transfer. However, such a maneuver contradicts the traditional dictum that any microanastomosis should be proximal to the zone of injury. A retrospective review of experiences with free flaps to the extremities corroborated this predilection for proximally-based flaps, which were successful in 115 of 136 cases (84.6 percent). Eleven distally-based flaps were also attempted: four were converted intraoperatively to proximally-based flaps; one was moved to an even more distal site, necessitating an interposition vein graft; and one totally failed. Although six (54.5 percent) distally-based flaps were ultimately successful, the incidence of problems encountered overall negated most benefits, so that this option for recipient vessels would rarely be justified.

Extremities↗
PubMed1996

Getting the most from the soleus muscle.

The bipennate soleus muscle has properly become entrenched as the muscle flap of choice for coverage of the middle third of the leg. Yet its potential versatility in fulfilling many other indications has been understated. With minor alterations in the methodology for transfer, often the reach of the muscle can be extended to more proximal or even distal defects in lieu of more complex solutions. Function preservation with hemisoleus flaps, the possibility of a cutaneous version, and use as a dynamic muscle demonstrate the diversity of additional alternatives. The merit of several techniques for augmenting circulation to the unreliable "reversed" soleus flap further prove the limitations of this option. Recognizing that we can often "get more" from the soleus muscle than traditionally considered deserves reemphasis.

Follow-Up Studies↗
PubMed1996

Distraction lengthening following growth cessation due to thumb replantation in a child.

Growth disturbance due to premature physeal closure as a sequela of digit replantation, on occasion, can cause shortening, resulting in suboptimal function. A simple method for correction using only local tissues is possible via gradual bony distraction. This was attempted in a toddler, whose dominant thumb was amputated by a riding lawn mower when he was an infant, because replantation caused significant growth cessation. The first metacarpal distraction over 64 days netted 22 mm of lengthening. Because a further immobilization period to allow spontaneous consolidation by neo-osteogenesis was aborted at the family's insistence, a fibular autograft of that dimension was inserted into the created bony gap. Ultimately, after 24 months of follow-up, the distracted thumb had been increased 26% in length and was 88% of the length of the contralateral thumb at that time, compared to only 74% prior to initiating the distraction.

Amputation, Traumatic↗
PubMed1996

Tendon-graft harvest using endoscopic guidance.

Traditional methods for harvesting tendon grafts using direct visualization commonly require multiple minute incisions or possibly a single incision if blind dissection by means of a tendon stripper is acceptable. Endoscope-assisted tendon-graft retrieval also can be limited to a solitary incision but, simultaneously because of the advantage of continuous visualization, permits a more precise and safer dissection as regards important contiguous anatomic structures. Upper extremity tendons can be readily manipulated by this technique, but at least with currently available equipment the more rigid deep fascia of the lower extremity so far has made such an adaptation cumbersome. The value of the surgical endoscope as an adjunct not only for tendon-graft harvest but perhaps someday for minimally invasive tendon transfer or tenolysis is encouraging.

Adolescent↗
PubMed1996

Distally based flaps for skin coverage of the foot and ankle.

Skin loss about the foot and ankle is notorious for creating a difficult challenge for limb salvage. Local tissue rearrangements rarely prove satisfactory, so a free flap as a solution can be readily justified. Distally based flaps utilizing unviolated ipsilateral proximal lower limb donor territories offer new possibilities in lieu of the complexity of microsurgery. Yet some unique disadvantages must be acknowledged particularly for island flaps, depending on retrograde circulation via major collateral source vessels, where venous congestion can occur and risk of limb devascularization may be unacceptable. Antegrade perfused, distally based flaps nourished by a single septocutaneous perforator or communicating branches may be more reliable options. This introduction to these three potential types of distally based lower extremity flaps is intended to promote this concept with appropriate reservations as another relatively simple alternative for wound coverage in the lower extremity.

Ankle↗
PubMed1996

Dog bites of the face with tissue loss.

Children are most frequently the victims of dog bites; the face is often the favored target. Even in apparently extensive injuries, enough skin generally remains to allow a reasonably direct closure, which is the preferred treatment. Infrequently, when significant soft tissue loss occurs, more complex methods require the surgeon's ingenuity in order to restore function and cosmesis without risking widespread infection or disfigurement. This article discusses the use of local flaps, skin grafts, or regional flaps in the proper circumstances. These options must be chosen carefully following an appropriate hierarchy of priorities, in order to achieve wound closure, to simultaneously restore anatomic landmarks, and to lessen the need for subsequent surgical revisions and psychological trauma.

Animals↗
PubMed1996

"Microleaps" in the progression of flaps and grafts.

No momentous upheavals in the past decade have altered radically the knowledge or application of "flaps and grafts," but "microleaps" in slow and steady increments have ensured a continuum of progress. Fasciocutaneous flaps, owing to an intimate relationship with the superficial nerves, may be neurocutaneous flaps in disguise. Distal-based flaps that recruit orthograde circulation may be made even more reliable for extremity coverage in lieu of complex microsurgical techniques. As success at the recipient site has not become so routine, further outcome improvement has been directed toward enhancing the appearance and residual function at the previously neglected donor site. The future of plastic surgery will continue to parallel advances in the principles of flaps, constrained only by the boundaries of imagination.

Female↗
PubMed1995

Forearm arterial loop as an expedient source for inflow to upper extremity free flaps.

Challenging wounds of the upper extremity requiring free tissue transfers are relatively infrequent. As a direct consequence, methods to access recipient vessels or acceptable alternatives may not be as familiar as in the lower extremity. In rare circumstances, creation of an arterial loop by elevation of a portion of either major forearm artery provides an easily accessible, pristine source of inflow for a planned free flap matching vessels of comparable caliber. Such a maneuver may also be important to ensure preservation of optimal hand function by avoiding any dissection in the vicinity of essential musculotendinous and neurovascular structures that might reside within or adjacent to the zone of injury.

Adult↗
PubMed1995

Closure of an ischial pressure sore using a free gastrocnemius musculocutaneous flap with a long venous pedicle.

The recurrent pressure sore in an active paraplegic can become a frustrating challenge as available simple flap options become depleted. The medial gastrocnemius musculocutaneous free flap is an alternative that offers the benefits of muscle from an expendable donor site and still preserves the remainder of the donor limb for future use. Inclusion of an intact greater saphenous vein could augment venous drainage and potentially might be the sole means of outflow if veins at the recipient site were inadequate. This case report describes the closure of a recurrent ischial pressure sore with a free medial gastrocnemius flap, including a greater saphenous vein pedicle.

Humans↗