Geoffrey G. Hallock

Type I and Type III Collagen Content of Healing Wounds in Fetal and Adult Rats

Abstract Full-thickness, dermal wounds were surgically created on the dorsa of fetal rats on the 17th day of gestation. The granulation tissue which developed after 2 days (19 days of gestation) was harvested from six to nine animals and pooled and the collagen was extracted with 0.5 M acetic acid and acetic acid plus pepsin. The ratio of type III:type I collagen was estimated from densitometer scans of electrophoretically separated α-chains. Full-thickness (to fascia depth) wounds were also produced on the dorsa of adult rats and granulation tissue which had developed for different periods of time up to 30 days was excised. Relative proportions of type III and type I collagen were assessed in normal and granulation tissues taken from the adult rats. Both fetal and adult granulation tissues have elevated type III collagen content but normal fetal tissue has a much higher content of type III than does normal adult tissue.

Direct and Indirect Perforator Flaps: the History and the Controversy.

LEARNING OBJECTIVES After studying this article, the participant should be able to: 1. Recognize the major role of the vascular supply to a cutaneous flap. 2. Predict its reliability. 3. Understand basic schemes for classification. 4. Realize that the evolution of these concepts is an ongoing dynamic process. Currently, the vascular supply to the fascial plexus is considered the factor of greatest importance in ensuring the reliability of any skin-bearing flap. The multiplicity of origins of the deep fascial perforators to this plexus has led to a bewildering array of terminology intended to encompass all possible flap options. A brief review of the history of the evolution of cutaneous flaps provides insight essential in understanding a simple proposal for their classification. Because all fascial perforators course either directly from a source vessel or indirectly first through some other tissue to ultimately reach the suprafascial layer, the corresponding flaps based on any such perforators could most simply be termed either direct perforator flaps or indirect perforator flaps, respectively.

Refinement of the radial forearm flap donor site using skin expansion

The radial forearm flap has proven to be versatile for free vascularized composite tissue transfers as well as for ipsilateral upper extremity reconstructions that require no microsurgical expertise. The most common objection to this otherwise advantageous donor area has been the subsequent nonaesthetic donor-site deformity. In addition, skin grafts frequently fail over the flexor carpi radialis tendon leading to chronic skin breakdown or at best tendon adhesions. Both these concerns may be ameliorated by means of tissue expansion of the remaining dorsal forearm skin to then allow removal of the skin-grafted portion of the donor site. These problems should be anticipated at the time of initial flap elevation so that the same incisions can be used for immediate placement of expanders.

Simultaneous transposition of anterior thigh muscle and fascia flaps: an introduction to the chimera flap principle.

A compound flap implies that more than a single tissue structure has been linked together to achieve a common purpose. In this sense then, a composite flap is the simplest form of a compound flap because by definition it incorporates multiple tissue types, but the latter are restricted in that the vascularization of all contained parts are interdependent and inseparable if total viability of the unit is to be maintained. More complex compound flaps may have components with separate vascular sources but remain physically attached, or may be fabricated by joining disparate flaps together using microsurgical methods. The chimeric flap, as still another type of compound flap, differs in that its tissue components may be independently maneuvered, remaining ultimately attached together only by some common regional source vessel or plexus. Concurrent, independent local transposition of the anterior thigh fasciocutaneous flap and rectus femoris muscle flap is used to demonstrate the chimera principle where these disparate flaps have been harvested from the same anterior thigh region.

In Utero Cleft Lip Repair in A/J Mice

Reconstructive in utero microsurgery for repair of unilateral cleft lips has been technically achieved in the A/J mouse fetus. The period of gestation was undisturbed, and following birth, the gross and histologic appearance of the lips was nearly normal with no evidence of scar formation. The absence of a lip scar after human cheiloplasty may require the as yet undefined advantages of fetal wound healing.

The propeller flap version of the adductor muscle perforator flap for coverage of ischial or trochanteric pressure sores

Recidivism after flap coverage of ischial and trochanteric pressure sores is predictably common. Available local flap options are limited in number and must be cautiously preserved as long as possible for these patients who are destined to have a lifelong vulnerability for recurrence. Muscle perforator flaps have been introduced as another set of alternatives to solve this conundrum. Since the posteromedial thigh often has been previously unviolated by the usual workhorse flaps selected for this problem, the adductor perforator flap will then usually still be available as an important “backup” option. If designed as a propeller flap, this version after rotation will cover the defect and simultaneously allow direct donor-site closure to avoid the need for a skin graft.

Anatomic basis of the gastrocnemius perforator-based flap

The gastrocnemius muscle is rarely considered today as a musculocutaneous flap. Yet, the posterior calf skin by itself can still be used to advantage as a source of local or perhaps free flaps. Fascial perforators in this region were reexamined in an anatomic study in 10 fresh cadaveric specimens to investigate the possibility of a gastrocnemius muscle perforator-based flap. At least two substantive perforators were found in all limbs, and there was always one overlying the medial gastrocnemius muscle (overall mean, 4.0 ± 1.8 perforators; range, 2–7 perforators). The origin of these perforators in any given specimen was most commonly as a secondary branch from the medial or lateral sural arteries alone (60%), from the median sural artery as a direct cutaneous branch alone (10%), or from either of the muscle pedicles and/or the median sural artery (30%). Thus, in 90% of limbs, the potential for elevating a gastrocnemius perforator-based flap exists without the need for any muscle sacrifice. Otherwise, a more traditional posterior calf fasciocutaneous flap was possible. Other deeper intramuscular collaterals were also identified so that sequential use of the muscle as a separate flap does not seem to be compromised.

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)

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 Workers 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. Our observed outcomes documented no clear superiority for endoscopic carpal tunnel release and should justify the continued use of a minimally invasive “open” technique by experienced hand surgeons without fear of personal obsolescence, especially if materiel expense is relevant or the risk for inadvertent injury is problematic. (Plast. Reconstr. Surg. 96: 941, 1995.)

Further clarification of the nomenclature for compound flaps.

Learning Objectives: After studying this article, the participant should be able to: 1. Understand the attributes and unique niche for compound flaps and their limitations. 2. Comprehend a proposed schema for further clarifying the classification of all types of compound flaps that is differentiated on the basis of the distinct vascular supply to each flap subtype. 3. Appreciate that minor technical modifications of known flaps of any type in general do not necessarily create a new category of flap. Background: A unique niche exists for compound flaps because of their extraordinary capability to allow repair of massive defects where the simultaneous restoration of multiple missing tissue components is demanded. The guidelines from the previous “simplified” classification schema need to be updated to allow a more complete clarification and further standardization of this concept. Methods: Compound flaps can be partitioned into two major classes that in turn are further differentiated into various subtypes according to their inherent pattern of circulation. Results: The subdivisions of compound flaps are those with a solitary source of vascularization and those with combinations of sources of vascularization. Those with a solitary source include composite flaps, defined as multiple tissue components all served by the same single vascular supply, and thereby consisting of dependent parts. Those flaps with combinations of sources of vascularization include (1) conjoined flaps, defined as multiple flap territories, dependent because of some common physical junction, yet each retaining its independent vascular supply; and (2) chimeric flaps, defined as multiple flap territories, each with an independent vascular supply, and independent of any physical interconnection except where linked by a common source vessel. Conclusions: Although many technical modifications have improved and will improve the reliability and versatility of compound flaps, these maneuvers alone should not be confused with creating distinct flap types but rather acknowledged to be only important variations. With this understanding, this revised nomenclature system for compound flaps is intended to be a means of standardizing communication and to facilitate research agendas on a common ground, fully realizing its primary role still only to serve as a convenient guideline.