Steven F. Morris

The neurovascular territories of the skin and muscles: anatomic study and clinical implications.

In 1987, the results of a series of total-body investigations of the arterial system of the skin and underlying deep tissues were published. This resulted in the angiosome concept. In 1990, a similar series of studies of the venous network was published. In both investigations, it was noted that “vessels hitchhike with nerves.” This anatomic study analyzes these neurovascular relationships in the skin and in the underlying muscles. Seven fresh human cadavers and nine animals were studied over a 2-year period. The entire integument of each and a total of 538 human and 72 animal muscles were removed and analyzed. Either the arterial or the venous system was injected with a radiopaque lead oxide mixture, and the dissected nerves were labeled with fine wires, being segregated later by a subtraction radiography technique. The results of these investigations are presented, with special emphasis placed on the design of long axial skin flaps placed along neurovascular systems and their relationship with the current design of skin flaps. The muscles are classified according to their extrinsic and intrinsic neurovascular supplies, and suggestions are made as to how they may or may not be subdivided into functional units for local and distant transfer. The cutaneous nerves, as well as the motor nerves of the muscles, were invariably accompanied by a longitudinal system of arteries and veins that often was the dominant supply to the region. Whether the nerves appeared together with the vessels, whether the nerves crossed them at an angle, or whether they approached the vessels from opposite directions, in each case the main trunk of the vessel or some of its branches soon “peeled off” to course parallel to the nerve. This information provides the basis for the design of long skin flaps placed along neurovascular systems. Indeed, it reveals that many of the current “axial” or “fasciocutaneous” skin flaps used in clinical practice are in fact neurovascular flaps. The muscles are classified into four types according to their extrinsic and intrinsic neurovascular supplies. Type I muscles are supplied by a single unbranched nerve. In type II muscles, the nerve branches before entering the muscle. Type III muscles receive multiple motor nerves from the same nerve trunk, and type IV muscles are supplied from multiple nerve trunks. Suggestions are made as to how muscles of each type may or may not be subdivided into functional neurovascular units for local and distant transfer. Our studies in the pig, monkey, dog, and rabbit reveal that the “blueprint” of the nerves is very similar when the animals are compared with each other and with humans. This information may help in planning future studies that focus on the neurovascular supply of the tissues in both the adult and the embryo.

Pharmacological Augmentation of Skin Flap Viability: A Hypothesis to Mimic the Surgical Delay Phenomenon or a Wishful Thought

The importance of the research in skin flap pharmacology is two-fold. First, observations made from the vasoactive drug actions in the vasculature of skin flaps can provide insight into the regulatory mechanism of cutaneous circulation and the pathophysiology of ischemic necrosis in skin flap surgery. Second, there is the possibility that the aforementioned information may eventually contribute to the development of a drug treatment for the augmentation of skin blood flow and viability in acute skin flaps (i.e., to mimic the surgical delay mechanism). To this end, the objectives of this article are: (1) to present a brief review of the recent research progress in the pharmacological treatment of ischemic skin necrosis in experimental flap surgery, and (2) to attempt to identify the future directions and important areas of research to be pursued in the pharmacology of skin flaps.

The superior and inferior gluteal artery perforator flaps.

Background: Perforator flaps have allowed reconstruction of soft-tissue defects throughout the body. The superior and inferior gluteal artery perforator flaps have been used clinically, yet the published anatomical studies describing the blood supply to the gluteal skin are inadequate. This study comprehensively evaluated the anatomical basis of these flaps to present anatomical landmarks to facilitate flap dissection. Methods: In six fresh cadavers, the integument of the gluteal region was dissected. Cutaneous perforators of the superior and inferior gluteal arteries were identified. Their course, size, location, and type (septocutaneous versus musculocutaneous) were recorded based on dissection, angiography, and photography. The surface areas of cutaneous territories and perforator zones were measured and calculated. Results: The average number of superior and inferior cutaneous perforators greater than or equal to 0.5 mm in the gluteal region was 5 ± 2 and 8 ± 4, respectively, with all of the superior and 99 percent of the inferior gluteal artery perforators being musculocutaneous. Their average perforator internal diameter was 0.6 ± 0.1 mm. The average superior and inferior gluteal artery cutaneous vascular territory was 69 ± 56 cm2 and 177 ± 38 cm2, respectively. The superior gluteal perforators were found adjacent to the medial two-thirds of a line drawn from the posterior superior iliac spine to the greater trochanter. The inferior gluteal artery perforators were concentrated along a line in the middle third of the gluteal region above the gluteal crease. Conclusion: The reliable size and consistency of the superior and inferior gluteal artery perforators allow the use of pedicled and free superior and inferior gluteal artery perforator flaps in a variety of clinical situations.

Neurovascular anatomy of the rectus femoris muscle related to functioning muscle transfer.

To describe the intramuscular neurovascular anatomy of the rectus femoris muscle and to evaluate whether the muscle can be split into two functional units, 40 rectus femoris muscle specimens were studied. Ten fresh human cadavers were injected with a mixture of lead oxide, gelatin, and water through the femoral arteries. The rectus femoris muscle with its neurovascular pedicles was dissected out and then radiographed. Computer wire was sutured to each nerve branch in the muscle, and the muscle was radiographed again. Radiographs with and without radiopaque wire were then analyzed. In 10 preserved cadavers, the rectus femoris muscle was dissected out. Note was made of the vessel and nerve to the muscle. All muscles were cut serially into 2-cm cross-sections, and the position and course of the intramuscular tendon were then grossly examined. Three different vascular patterns in 40 rectus femoris muscles were found, based on the number of vascular pedicles and their relative dominance within the muscle. The rectus femoris muscle received either a single vascular pedicle (12.5 percent), a dominant vascular pedicle and one or two minor pedicles (80 percent), or two dominant vascular pedicles (7.5 percent). The rectus femoris was innervated by a large nerve branch from the posterior division of the femoral nerve, and the branch generally divided into two sub-branches before it reached the muscle. Both branches were respectively accompanied by arterial branches to form neurovascular hila. Furthermore, this present study has provided a detailed description of the intramuscular neurovascular territories. Also, the pattern of neurovascular supply of the muscle makes it possible to subdivide the muscle into two functional units for segmental muscle transfer.

A review of vascular injection techniques for the study of perforator flaps.

Background: With a new era of flap surgery, additional anatomical information is required. The relatively recent interest in musculocutaneous perforator flaps has once again sparked interest in the vascular anatomy of surgical flaps. There are a variety of anatomical techniques available to define the vascular anatomy of tissues of interest. In this article, the authors review vascular injection techniques available and describe the technique currently used in their laboratory. Methods: A comprehensive review of vascular injection techniques is summarized. Barium sulfate and lead oxide in particular are reviewed in detail. Results: This article reviews the historical development of vascular injection techniques, outlines current investigative methods, and expands on a radiopaque lead oxide and gelatin injection method that provides high-quality angiograms. Conclusions: The standard method for the study of perforator flap is the lead oxide–gelatin technique. However, other methods can provide complementary information on vascular anatomy.

The vascular basis of the thoracodorsal artery perforator flap.

Background: Musculocutaneous perforator flaps, or more simply, perforator flaps, have become increasingly popular in microsurgery because of numerous advantages, including reduced donor-site morbidity. The thoracodorsal artery perforator flap is a cutaneous flap based on cutaneous perforators of the thoracodorsal vessels. The objective of this study was to document the vascular anatomy of this flap in human cadaveric studies. Methods: The anatomy of the perforators of the thoracodorsal artery was studied using a modified lead oxide–gelatin injection technique in 15 fresh human cadavers. Each fresh cadaver was injected with lead oxide, gelatin, and water, and then cooled to 4°C for 24 hours before dissection. The torso was dissected to identify all cutaneous perforators in the region of the back and flank. Results: The mean area of the primary and secondary zones supplied by the thoracodorsal artery was 255 cm2 and 345 cm2, respectively. The mean length of the major and minor axes was 18 cm and 13 cm, respectively. The maximum dimensions of the skin that could potentially be supplied by the thoracodorsal artery averaged 600 cm2, with a major axis length of 28 cm and a minor axis length of 27 cm. A mean number of 5.5 perforators with a mean diameter of 0.9 mm (range, 0.5 to 1.5 mm) supplied this zone. The ratio of musculocutaneous to septocutaneous perforators from the thoracodorsal artery was 3:2. The length of the thoracodorsal pedicle when harvested along with the perforator was 14.0 cm, with the vessel diameter being 2.8 mm at the origin. The most proximal perforator was seen at the level of the inferior angle of the scapula, 3.0 cm medial to the anterior border of the muscle. The intramuscular course of the perforators averaged 5 cm (range, 3 to 7 cm). Septocutaneous perforators from the thoracodorsal artery supplying the skin in addition to the musculocutaneous perforators were seen in 60 percent of specimens. Conclusions: The thoracodorsal artery perforator flap is a reliable cutaneous perforator flap that is very useful in a wide variety of clinical applications.

Local delivery of adipose-derived stem cells via acellular dermal matrix as a scaffold: a new promising strategy to accelerate wound healing.

Wounds, characterized by leading to a loss of integrity of the skin and a major cause of morbidity and mortality, are common challenges encountered in plastic and reconstructive surgery. The primary goals of treatment are rapid closure, restoration of function, and aesthetical satisfaction. Adult stem cells may provide new strategies to treat cutaneous wounds because of their prolonged self-renewal capacity and ability to differentiate into various tissues. In the past five years, some researches discovered bone marrow mesenchymal cells (BMSCs) could accelerate wound healing. However, there exist several disadvantages of BMSCs mainly including the limitation of the obtainable amount and the impairment of their differentiation abilities with the increasing age. Due to the limitation of BMSCs in clinical application, we turn to consider adipose-derived stem cells (ASCs) as seeding cells in tissue repair for their own advantages. ASCs could not only possess capacity to differentiate into various lineages under appropriate conditions, but also release angiogenic factors that stimulate angiogenesis in ischemia injury models. Here we propose the hypothesis that ASCs locally delivered via acellular dermal matrix as a scaffold would enhance wound healing through both differentiation into endothelial and epithelial cells and production of angiogenic growth factors in cutaneous wounds. Furthermore, ASCs seeded acellular scaffold can be believed to offer more benefits for introducing stem cells to the local ischemia environment as it provides a framework for the support of their regenerative capacity. Therefore, if the hypothesis is proved to be practical, it might represent a novel therapeutic approach and enhance cutaneous wound healing more effectively.

Prospective Study of Outcomes after Reduction Mammaplasty

Background: The purpose of this study was to prospectively assess changes in overall health-related quality of life and breast-related symptoms in women undergoing reduction mammaplasty, and to compare preoperative and postoperative health-related quality of life with that of the normal population. Methods: Fifty-six patients were evaluated preoperatively and 6 months postoperatively with three questionnaires: the Short Form-36 Health Survey, the Symptom Inventory Questionnaire, and the Rosenberg Self-Esteem Scale. Surgeons completed preoperative patient assessment forms, operative note forms, and postoperative patient assessment forms. Results: Comparison of preoperative and postoperative health-related quality of life showed significant improvements in Short Form-36 Health Survey scores (p < 0.005), the Rosenberg Self-Esteem Scale (p < 0.001), and all symptoms on the Symptom Inventory Questionnaire (p < 0.003). Preoperative mean Short Form-36 Health Survey scores were lower than in the normal population in several areas (p < 0.005). Postoperatively, none of the mean Short Form-36 Health Survey scores were significantly lower than population norms. Conclusions: This study determined that there is a significant improvement of physical symptoms and health-related quality of life in women undergoing reduction mammaplasty at 6 months after surgery. Before surgery, these patients have a significantly worse health-related quality of life than the normal population, but they normalize postoperatively.

Assessment of ischemia-induced reperfusion injury in the pig latissimus dorsi myocutaneous flap model.

Experiments were conducted to assess ischemia-induced reperfusion injury in the pig latissimus dorsi myocutaneous flap model. Forty Yorkshire pigs (19.5 +/- 0.6 kg) were assigned to groups A, B, C, and D (n = 10 pigs). Bilateral 8 x 13 cm latissimus dorsi myocutaneous flaps were constructed in each pig, and one flap was assigned to ischemic treatment and the contralateral flap served as a nonischemic control. The treatment flaps in groups A, B, C, and D were subjected to 2, 4, 6, and 8 hours of warm global ischemia, respectively. Pigs in groups A, B, C, and D were divided into two subgroups (n = 5 pigs), and extents of skin and muscle necrosis in control and treatment flaps were assessed with the fluorescein and nitroblue tetrazolium dye stain tests, respectively, after 2 and 7 days of reperfusion. Significantly (p < 0.01) greater extents of skin and muscle necrosis were observed in latissimus dorsi myocutaneous flaps subjected to 4, 6, or 8 hours of ischemia compared with their contralateral controls. Extents of skin and muscle necrosis also increased significantly (p < 0.01) with increases in ischemia time in treatment flaps. Of particular importance was the observation that there was no significant difference in the extent of skin or muscle necrosis between 2 and 7 days of reperfusion in all control and treatment groups. This observation indicates that 2 days of reperfusion time is adequate to assess the maximum extent of skin and muscle ischemia-induced reperfusion injury in pig latissimus dorsi myocutaneous flaps. Furthermore, it was observed that 1-cm segments of latissimus dorsi muscle were not too thick to allow the use of the nitroblue tetrazolium dye stain test for assessment of muscle viability, as judged by the highly correlated (r = 0.98, n = 40) linear relationship between assessment of muscle viability from one transverse cut surface of muscle segments and by weighing total viable and nonviable muscles dissected from the flaps according to the nitroblue tetrazolium dye stain on both transverse cut surfaces. It is important to note that the maximum length of the latissimus dorsi myocutaneous flap model for ischemia-induced reperfusion injury research should not exceed the maximum length of skin viability in the nonischemic control in order to avoid the complication of skin necrosis due to excessive length of skin.(ABSTRACT TRUNCATED AT 400 WORDS)

The Posterior Thigh Perforator Flap or Profunda Femoris Artery Perforator Flap

Background: The thigh donor site has been used extensively for microsurgical tissue transfer; however, the posterior thigh has been neglected as a potential donor site. The perforators of the profunda femoris artery supply large cutaneous territories that could be useful for lower extremity coverage. The purpose of this article is to evaluate the anatomical basis of the posterior thigh perforator flap and to provide anatomical landmarks with which to facilitate flap dissection. Methods: Six fresh cadavers underwent a whole-body, intraarterial injection of a lead oxide and gelatin preparation. The integument of the posterior thigh was dissected (n = 11), and perforators of the profunda femoris artery were identified. Their type (septocutaneous versus musculocutaneous), course, size, and location were documented by angiography and photography. Surface areas were measured with Scion Image Beta 4.02. Results are reported as mean ± SD. Results: The average number of profunda femoris cutaneous perforators in the posterior thigh was 5 ± 2 (65 percent septocutaneous and 35 percent musculocutaneous), the average internal diameter was 0.8 ± 0.3 mm, and the pedicle length was 29 ± 14 mm from the deep fascia and 68 ± 33 mm from the profunda femoris artery. The average profunda femoris cutaneous vascular territory was 229 ± 72 cm2, with a 46 ± 13-cm2 perforator zone. Cutaneous perforators can be found on a line extending from the ischium to the lateral femoral condyle. Conclusions: The profunda femoris provides cutaneous perforators of large caliber supporting a substantial cutaneous territory. This flap will likely be clinically useful in lower extremity reconstruction as a free or pedicled flap.