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Biomedical subjects

G G Hallock

Publications and source records attributed to G G Hallock.

At least 73 records · Page 4Linked to original sources
PubMed1995

Microsurgical transfer of vascularized tissue to close problem wounds.

Interventions to achieve optimal wound healing challenge the skills of all health care professionals. Although most wounds are best managed by appropriate nursing intervention outside the OR, some complex wounds require more expeditious closure to ensure maximum preservation of vital structures and their functions. Microsurgical transfer of vascularized tissue (ie, flaps) often is the only method of achieving immediate wound coverage. Perioperative team members who treat such wounds must be aware of the distinct attributes and potential morbidity associated with flap procedures.

Female↗
PubMed1995

Efficacy of free flaps for pediatric trauma patients in an adult trauma center.

Although many trauma centers are primarily "adult-oriented," the presentation of unusual life- or limb-threatening wounds in children occasionally have mandated urgent microvascular tissue transfer for salvage. For these rare instances, should a microsurgical team accustomed to dealing with adult trauma patients even attempt to meet such a specialized challenge? A retrospective analysis of all free flaps performed by the author's team in trauma patients from 1984 to 1993, revealed only 10 pediatric patients who had had 11 separate free flaps. Their ultimate success rate was 90.9 percent--statistically the same rate (87.0 percent) as for 93 adult free flaps. The majority of these pediatric flaps were for urgent coverage of the lower extremity and they were all successful, eliminating any need for traditional pedicled flaps during the same time period. Improvement in technical expertise and judgment seemed to be more important factors than actual chronological age in determining free-flap success in general, and in children in particular. Therefore, free flaps in the pediatric population can be appropriately performed in an adult trauma center.

Adolescent↗
PubMed1995

Endoscopic retrieval of the sural nerve.

The rapid proliferation and applications of endoscopic-guided systems have transcended all surgical specialties. The future as regards reconstructive microneurosurgery is uncertain but inevitable, as already characterized by efforts to seek an alternative method for harvest of the sural nerve. Although still a primitive technique, endoscopic assistance in the retrieval of long, sural-nerve grafts has been found to minimize the trauma and morbidity of dissection; can simplify identification of frequently anomalous branches; and allows a reduction of the number of incisions, to improve the aesthetic result.

Endoscopes↗
PubMed1995

Endoscope-assisted suction extraction of lipomas.

The blunt technique of suction-assisted lipectomy partially evolved while proving to be an efficient, albeit blind, method for the removal of lipomas. Larger or poorly encapsulated tumors were acknowledged to be at a greater risk for recurrence probably because of an unrecognized residua. Just as liposuction has enhanced body-contour surgery because of the potential for smaller and fewer scars hidden in strategically camouflaged locations, the identical advantages are possible for liposuction extraction of lipomas, with a greater assurance for their entire removal via direct visualization using a surgical endoscope.

Endoscopy↗
PubMed1995

Transverse rectus abdominis musculocutaneous (TRAM) flap from TRAM flap for sequential bilateral breast reconstruction.

Sequential as opposed to synchronous autogenous tissue bilateral breast reconstruction imposes a dilemma because of the increasing complexity of the usually few remaining options. This fact became evident 4 years after an ipsilateral superior-pedicled lower transverse rectus abdominis musculocutaneous (TRAM) flap for left-breast reconstruction was successful in a patient who only then desired a prophylactic contralateral mastectomy but also demanded breast symmetry without implants. Without resorting to microsurgical transfers and foregoing local delay tactics, a right-breast facsimile was formed via an adaptation of breast-sharing principles. Transverse splitting of the original TRAM flap with re-elevation of the inframammary half of the reconstructed breast still maintained viability through the retained medial left rectus abdominis muscle pedicle. This second TRAM flap was immediately transposed to the opposite side without incident. Although only a fair overall aesthetic result was possible, the patient's expectation for having two "breasts" was met.

Female↗
PubMed1995

Physiologic superiority of the anatomic dominant pedicle of the TRAM flap in a rat model.

Despite an extensive knowledge of the anatomic nuances of the rectus abdominis muscle and corresponding relationship to the vascularization of the skin of the abdomen, the clinical outcome when used as a musculocutaneous flap cannot always be predictable. Only a few human physiologic studies have been attempted to explain this discrepancy. Further laboratory investigations of the anatomy and physiology of the rat transverse rectus abdominis musculocutaneous (TRAM) flap suggest that this is a safer, comparable, yet inexpensive animal model for studying further the dynamics of this flap. By caliber and course, the major source vessel to the rectus abdominis muscle in the Sprague-Dawley rat enters superiorly as the cranial epigastric artery, which is a continuation of the internal thoracic (mammary) artery. Anatomic dissections in 13 rats revealed, on average, that 4.7 +/- 0.97 large musculocutaneous perforators emanated from each cranial epigastric artery at regular intervals which then proceeded directly to the overlying abdominal integument. Just below the umbilicus, a watershed is formed by small "choke" anastomoses to a frequently vestigial caudal epigastric artery or, more commonly, a true anastomosis with a branch of the deep circumflex iliac artery. In 10 additional rats, TRAM flaps encompassing the skin of the entire abdominal wall were then elevated so as to rely on a single pedicle, alternating randomly from either source. By laser Doppler flowmetry, blood flow by means of the larger-caliber superior pedicle exceeded twice that of the subservient inferior pedicle.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

Safety of clinical overinflation of tissue expanders.

Despite adherence to a rigorous methodology with precise preexpansion calculations that culminate in the selection of an appropriate implant, the predicted surface area gain after completion of tissue expansion often falls short of the clinical requirements. Rather than then resorting to serial expansions, cutaneous overexpansion usually can be achieved to reach the desired dimensions by overinflation of the implant even well beyond the vendor's stated maximum volume. Over the past decade in a series of 69 patients using 97 tissue expanders, some degree of overexpansion was utilized in 53 implants (54.6 percent). No adverse sequelae due to mechanical failure specifically attributable to this hyperinflation occurred. Complications in the overinflation group (18.9 percent) actually were significantly fewer than those observed in the underexpanded (41.9 percent) (p < 0.03) but were similar in classification. Rather than any inherent superiority in the former group, this observation probably more accurately reflects the fact that overexpansion rarely could be done practically after a significant complication. In any event, the proven safety of limited clinical overexpansion allows a margin of error in the initial choice of implant volume and later permits continued expansion if more tissue than originally anticipated is needed.

Equipment Failure↗
PubMed1995

Prospective comparison of minimal incision "open" and two-portal endoscopic carpal tunnel release.

Part of the groundswell for endoscopic plastic surgery initially gained momentum in hand surgery, with claims that endoscopic carpal tunnel release allowed less invasive surgery and a more rapid recovery due to diminished pain and scarring than was possible with traditional "open" methods. Admittedly, no ultimate difference in their efficacy as regards symptom relief had been observed. However, in our opinion, some of these conclusions may be flawed, since an "open" method employing the most minimal possible incisions was not necessarily used. Therefore, a more apropos study should compare an acceptable minimally invasive "open" technique versus endoscopic carpal tunnel decompression. A prospective, consecutive series of 96 patients with medically unresponsive, confirmed carpal tunnel syndrome with no other concomitant hand pathology was selected. Fifty-three patients (71 hands) underwent "open" release using a minimal incision, which was comparable in composition to a group of 47 patients (66 hands) who had a two-portal endoscopic release. Scar length (p = 0.999), need for hand therapy (p = 0.798), rate of complications (p = 0.359), length of time before resuming routine activities (p = 0.255), and length of time before return to work (p = 0.373) were not statistically different whether an "open" or "closed" procedure had been performed. Regardless of the technique employed, individuals receiving Worker's Compensation more often required hand therapy (p < 0.02) and had a significantly longer recovery period (p < 0.005). A subgroup of 15 patients with bilateral carpal tunnel syndrome who had decompression using opposing methods had no significant difference in preference.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1995

Evidence for the efficacy of TRAM flap delay in a rat model.

The dilemma in selecting a variant of the transverse rectus abdominis musculocutaneous (TRAM) flap for autogenous tissue breast reconstruction is to balance maximal flap perfusion against the sacrifice of abdominal-wall integrity. A surgical delay has been suggested as one very simple fascia-sparing technique that simultaneously augments flap volume, but no randomized clinical studies have been performed to prove whether there is any benefit whatsoever following such a maneuver. Because large groups of nearly identical subjects may be more readily available for comparison in an animal model, the rat TRAM flap provides an inexpensive method to further investigate the delay phenomenon in this setting. Staged procedures were performed in 15 Sprague-Dawley rats initially causing a delay by division of one or both dominant vessels (cranial epigastric) supplying the rectus abdominis muscles. Either 2 or 4 weeks later, TRAM flaps were elevated based only on the subservient (caudal epigastric) pedicle. A control group of 7 rats with immediate formation of a TRAM flap had a mean survival of 46.3 +/- 15.37 percent of their original flap surface area. After a 2-week delay, viability was 50.2 +/- 17.54 percent for ipsilateral and 39.4 +/- 7.57 percent for flaps with prior bilateral dominant pedicle division. Neither was significantly different from control (p = 0.68 and 0.38, respectively). However, the ipsilateral 4-week delayed group had 67.8 +/- 8.96 percent flap survival, which represented a significant enhancement when compared with the undelayed control TRAM flaps (p < 0.02).(ABSTRACT TRUNCATED AT 250 WORDS)

Abdominal Muscles↗
PubMed1995

The fallacy of presumed superiority of proximally based versus distally based flaps.

As our knowledge of the origin of the cutaneous circulation becomes more precise, many preconceived notions continue to be abandoned. In this context, the general rule that distally based flaps are inherently inferior to proximally based flaps also should appropriately be challenged. To disprove this long-standing dictum, multiple abdominal flaps were simultaneously elevated in 15 Sprague-Dawley rats that included or excluded all possible combinations of musculocutaneous or axial skin perforators from each major source vessel (cranial or caudal epigastrics, superficial epigastric or lateral thoracic, respectively). These flaps were sequenced randomly in each rat to have superior (proximal) or inferior (distal) pedicles such that at least five flaps of each subtype were analyzed. Mean flap survival when the specific source vessel was retained uniformly was significantly greater than in all flaps where the source vessel had been excluded regardless of the orientation of the flap pedicle. All flaps with intact circulation had no significant difference in mean flap survival. Similarly, when normal flap circulation was excluded, no difference was observed in mean flap survival. Again, both these observations were true irrespective of the location of the flap base. Thus the major factor in determining flap viability was not whether its pedicle was proximally or distally based but rather the origin and quality of its intrinsic blood supply.

Animals↗
PubMed1995

Preoperative identification of perforating vessels to the skin by color duplex imaging.

Recent improvements in high-frequency linear array transducers with color duplex imaging permit the precise identification and estimation of the caliber of minute perforating vessels to the skin as small as 0.5 mm. An obvious corollary role would be the accurate preoperative delineation of the vascular anatomy of a skin flap, which could be essential to ensure its viability. This technology was then applied to map the blood supply to skin flaps in eight patients, which was subsequently verified at the time of their actual surgical dissection. Because anomalies of the skin circulation are not uncommon, this extended capability for color duplex imaging can facilitate a more optimal design of skin flaps to better ensure their chance for survival by the inclusion of appropriate nutritive blood vessels.

Blood Vessels↗
PubMed1995

Self-inflicted gunshot wounds of the lower half of the face: the evolution toward early reconstruction.

The self-inflicted gunshot wound of the lower half of the face traditionally has been treated by multistaged and prolonged reconstructive maneuvers that often left significant and uncorrectable secondary deformities. Modern cranio-maxillofacial methods for reduction and rigid fixation of the facial skeleton, using immediate autogenous bone grafts when required, also has been efficacious for the acute management of these severe gunshot injuries. These methods can reduce the previously expected morbidity. Today's improved outcomes also are a consequence of the use of more reliable regional flaps and microsurgical techniques, which permit the early and simultaneous restoration of bone and soft tissue loss once all devitalized tissues have been adequately debrided.

Aged↗
PubMed1994

Identical rectus abdominis donor-site morbidity in compromised and healthy patients.

As microvascular capabilities improve, donor-site complications may become of greater concern. This has become an issue, particularly with the rectus abdominis muscle which is unique, as weakening of abdominal-wall integrity is always a potential problem. The author has reviewed all 50 of his pedicled and free-flap transfers of the rectus abdominis muscle, comparing healthy and chronically ill patients, for elective and emergent indications. Twelve percent of patients had donor-site complications, identical for both healthy and ill patients; 11.4 percent of pedicled flaps and 13.3 percent of free flaps had compromised outcomes. Three hernias occurred as major complications, which probably could not have been avoided. Nevertheless, these frequencies were within the range of expected complications, as with any muscle-flap donor site. The merit of this flap at the recipient site usually justified the risks and, in spite of appropriate risks and, in spite of appropriate trepidation regarding this donor site, the benefit of this flap should not be denied, even for the unhealthy patient.

Adult↗
PubMed1994

The random upper posterior thigh fasciocutaneous flap.

A superiorly based random posterior thigh fasciocutaneous flap has evolved as a coexisting variant of the gluteal thigh composite flap, which is frequently important due to commonly encountered vascular anomalies in this region, such as absence of the descending branch of the inferior gluteal artery. This flap is distinguished by its reliance on the longitudinally oriented axis of the fascial plexus of the upper posterior thigh that is serviced predictably by multiple perforators from the cruciate anastomosis. In a series of 8 such flaps used in 7 patients over the past 10 years, only a single major complication has ensued. Therefore, it has proved to be of tremendous value as another simple, rapidly elevated option to close adjacent ischial or trochanteric defects; it supplements the other known flaps needed here because there is always a high risk of pressure sore recurrence. No muscle needs to be sacrificed, making this flap also a reasonable alternative for the ambulatory patient.

Dermatologic Surgical Procedures↗
PubMed1994

The medial approach to the sural vessels to facilitate microanastomosis about the knee.

Complex wounds about the knee in rare instances may justify the selection of a distant microvascular tissue transfer for coverage. A major preoperative consideration then is the choice of an appropriate recipient site for revascularizing the flap that is outside the zone of injury, and preferably avoids the need for vein grafts. In many cases, the heads of the gastrocnemius muscles have protected the sural vessels from injury, allowing these to be used as a vascular extension of the popliteal system to simplify the required microanastomoses in an end-to-end fashion. Access to the sural vessels can be readily achieved through a medial approach to the popliteal fossa that permits the patient to remain supine or lateral on the operating table for simultaneous exposure of multiple privileged donor sites.

Anastomosis, Surgical↗