Maolin Tang

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.

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.

Relationship Between Hypovascular Zones and Patterns of Ruptures of the Quadriceps Tendon

BACKGROUND Compromised vascularity and hypoxia have been proposed as risks for tendon ruptures. The density of vascularity of the quadriceps tendon may explain the pattern of ruptures of this muscle-tendon unit. METHODS Twenty adult human cadavers underwent whole-body arterial perfusion with a mixture of lead oxide, gelatin, and water through the femoral artery. Thirty-three quadriceps tendons were dissected and radiographed, and each angiogram was analyzed with use of image statistical software. RESULTS We consistently identified a hypovascular zone located between 1 and 2 cm from the superior pole of the patella. This finding correlates with the location of spontaneous ruptures of the quadriceps tendon reported in the literature. These findings indicate that the vascular supply of the quadriceps tendon is separated into three arcades, or arches, which are medial, lateral, and peripatellar. CONCLUSIONS Hypovascularity may determine the site of spontaneous ruptures of the quadriceps tendon. CLINICAL RELEVANCE Understanding the vascular zones of the quadriceps tendon may facilitate the use of nonoperative as well as operative treatments to increase the vascularity of the tendon. An understanding of the vascular arcades may facilitate and enhance healing following reparative and reconstructive surgery on the tendon.

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.

The Vascular Basis of Perforator Flaps Based on the Source Arteries of the Lateral Lumbar Region

Background: Perforator flaps based on the integument of the trunk have been well described in the literature; however, the anatomy of many donor sites has yet to be adequately documented. The integument of the lateral lumbar region of the trunk is supplied by a number of source arteries (lower posterior intercostal, lumbar, superior epigastric, deep inferior epigastric, superficial inferior epigastric, superficial circumflex iliac, deep circumflex iliac) whose large perforators may be suitable for perforator flap harvest. The purpose of the current study was to describe the vascular anatomy of these perforators in the lateral lumbar region. Methods: A series of five fresh human cadavers were studied using a lead oxide–gelatin injection technique. The integument of the trunk (10 sides or hemitrunk specimens) was dissected, and the perforating vessels (diameter ≥0.5 mm) were identified, noting vascular origin, diameter, and pedicle length. Radiographs of tissue specimens were digitally analyzed using the software Scion Image for Windows (Scion Corp., Frederick, Md.) to determine vascular territories. Results: The source vessels contributed a summed mean of 33 perforators per hemitrunk, with a mean emerging vessel diameter of 0.7 ± 0.2 mm and a corre- sponding mean superficial pedicle length of 31 ± 24 mm. The total area of skin supplied directly by these 33 perforators was 1200 cm2, equating to a mean area of 37 cm2 per perforator. Conclusion: The authors have comprehensively described the anatomy of perforators of the lateral lumbar region of the trunk.

A pilot study on three-dimensional visualization of perforator flaps by using angiography in cadavers.

Background: Perforator flaps have become popular worldwide, in part because of their ability to reliably support a large skin territory on a single perforator. Although the lead oxide injection technique provides excellent images for anatomical study, it is not possible to show the location, course, and direction of the source artery. Materialise’s Interactive Medical Image Control System allows microvascular anatomy to be evaluated in three-dimensions to design perforator flaps. Methods: Two fresh cadavers were injected using the lead oxide–gelatin injection technique. The cadavers were imaged using a spiral computed tomography scanner. The computed tomographic data were transferred to Digital Imaging and Communications in Medicine format and imported to a personal computer. Three-dimensional reconstructions of various parts of the body were then performed using Materialise’s Interactive Medical Image Control System software. Results: Three-dimensional visualization of various parts of the body was obtained. This technique clearly shows the bone, soft tissue, skin, and vascular structures in a layer-by-layer transparent process. The detailed views of the microvasculature provide extensive information regarding the course of vessels in all layers of tissue. Conclusions: The intricate vascular details captured by this technique clearly demonstrate the three-dimensional anatomy of the integument, bone, and soft tissue in a layer-by-layer transparent process. It is a powerful, quick, easy method with which to demonstrate cadaver vascular anatomy that may be useful in the design of surgical flaps.

The anatomical basis of the deep circumflex iliac artery perforator flap with iliac crest

Background: Perforator flaps are increasingly used because of advantages including reduced flap bulk, less donor-site morbidity, and more donor-site options. The deep circumflex iliac artery (DCIA) osteomusculocutaneous flap with iliac crest has been one of the most useful flaps used for mandibular reconstruction. However, its use has been limited by its bulkiness and added donor-site morbidity because of the inclusion of an “obligatory muscle cuff” of abdominal muscle. Early results at designing a DCIA perforator flap to circumvent this problem have been varied. Details regarding the location, number, and reliability of DCIA musculocutaneous perforators have been conflicting. The purpose of this study was to comprehensively document the anatomical basis of the DCIA perforator flap. Methods: Six fresh bodies underwent whole-body lead oxide injection (n = 12 specimens). Landmarks were identified with radiopaque markers. Dissection, angiography, and photography were used to document the precise course of individual perforators in the flank region. Angiograms were assembled with Adobe Photoshop and analyzed with Scion Image Beta. Results: An average of 1.6 DCIA perforators with a diameter of 0.7 mm was present in 92 percent of specimens. Perforators were located 5 to 11 cm posterior to the anterior superior iliac spine, 1 to 35 mm superior to the iliac crest, with a perforator zone of 31 cm2. The DCIA perfused the medial aspect of the iliac crest. Conclusions: This article establishes the anatomical basis of the DCIA perforator flap with iliac crest. This perforator flap, along with a split iliac crest, will likely diminish donor-site morbidity and facilitate oromandibular reconstruction.

Three-dimensional analysis of perforators of the posterior leg.

Background: Three-dimensional evaluations of cutaneous perforator vessels provide useful clinical information to aid in the design of perforator flaps. By combining three-dimensional digital imaging and angiography, the authors developed a new three-dimensional visualization technique for vascular perforators. Their purpose was to produce a digitized model of the posterior leg to determine the anatomical relationships of perforators in each zone of the posterior leg. Methods: Eight cadavers were injected with a modified lead oxide–gelatin mixture. Two cadavers were selected for three-dimensional reconstruction using a spiral computed tomography scanner and specialized volume-rendering software. Dissection, angiography, and photography of each layer were performed to outline the course of every perforator in the posterior leg. The area of the vascular territory supplied by each source vessel was calculated. Surface areas were measured using Scion Image software. Results: The arterial supply to the integument of the posterior leg was divided into proximal, middle, and distal zones. There were 13 ± 2.3 perforators with diameters of greater than or equal to 0.5 mm; the average external diameter was 0.8 ± 0.2 mm. Each perforator supplied an average area of 38 ± 9.0 cm2. Perforators from the popliteal artery were large and consistent and supplied an average area of 55 ± 20 cm2; there were multiple anastomoses between perforators from the popliteal, posterior tibial, and peroneal arteries. The distal zone received its arterial supply from two to three smaller septocutaneous perforators, which are arranged longitudinally in one to two parallel chains. Conclusions: The posterior leg is an excellent donor site for local and distant flaps. Perforator flaps could be based in a variety of ways from each zone.

Reversed forearm island flap supplied by the septocutaneous perforator of the radial artery: anatomical basis and clinical applications.

The cutaneous perforators of the radial artery adjacent to the superficial branch of the radial nerve and the lateral antebrachial cutaneous nerve were investigated, and the vascular anatomical features of the reversed forearm island flap supplied by those accompanying perforators were documented. Ten fresh cadavers were systemically injected with lead oxide, gelatin, and water. Twenty forearms were then dissected, and an overall map of the cutaneous vasculature and source vessels was constructed. The accompanying arteries were observed to lie along the lateral antebrachial cutaneous nerve and the superficial branch of the radial nerve and to nourish the skin through cutaneous branches. Vascular communication among these cutaneous vessels was evaluated, to determine the cutaneous vascular territory of the radial forearm flap. This anatomical information facilitates flap design in the forearm region. Clinical experience regarding the usefulness of the reversed forearm island flap for hand reconstruction for a series of five patients is presented.