Cara Michelle Le Roux

The perforator angiosome: A new concept in the design of deep inferior epigastric artery perforator flaps for breast reconstruction

Background: The previously described “perfusion zones” of the abdominal wall vasculature are based on filling of the deep inferior epigastric artery (DIEA) and all its branches simultaneously. With the advent of the DIEA perforator flap, only a single or several perforators are included in supply to the flap. As such, a new model for abdominal wall perfusion has become necessary. The concept of a “perforator angiosome” is thus explored. Methods: A clinical and cadaveric study of 155 abdominal walls was undertaken. This comprised the use of 10 whole, unembalmed cadaveric abdominal walls for angiographic studies, and 145 abdominal wall computed tomographic angiograms (CTAs) in patients undergoing preoperative imaging of the abdominal wall vasculature. The evaluation of the subcutaneous branching pattern and zone of perfusion of individual DIEA perforators was explored, particularly exploring differences between medial and lateral row perforators. Results: Fundamental differences exist between medial row and lateral row perforators, with medial row perforators larger (1.3 mm vs. 1 mm) and more likely to ramify in the subcutaneous fat toward the contralateral hemiabdomen (98% of cases vs. 2% of cases). A model for the perfusion of the abdominal wall based on a single perforator is presented. Conclusion: The “perforator angiosome” is dependent on perforator location, and can mapped individually with the use of preoperative imaging.

The venous anatomy of the anterior abdominal wall: an anatomical and clinical study.

Background: Despite improving outcomes, venous problems in the harvest of deep inferior epigastric artery perforator (DIEP) flaps remain the more common vascular complications. However, it is apparent that the venous anatomy of the anterior abdominal wall has not been described to the same extent as the arterial anatomy. Previous anatomical studies have focused on cadaveric anatomy or excisional specimens. The current study uses in vivo computed tomographic angiography to evaluate this anatomy, in combination with a cadaveric radiographic study. Methods: Both cadaveric and in vivo studies were undertaken using eight whole fresh cadaveric specimens (16 sides) and 100 patients undergoing DIEP flap breast reconstruction (200 sides). The cadaveric component used direct catheter venography and the in vivo studies were undertaken using preoperative computed tomographic angiography, mapping in vivo venous flow. Results: The location, caliber, course, and distribution of the superficial and deep inferior epigastric veins were recorded. The dominance of each system and their direction of drainage were described. Mechanisms for poor venous drainage were postulated, including perforator size, midline crossover of the superficial inferior epigastric vein, and the superficial and deep inferior epigastric vein communications. The incidence of each of these anatomical factors was evaluated. Conclusion: The cause of venous compromise is multifactorial, with the current study showing that preoperative computed tomographic angiography may predict venous problems during flap harvest, by demonstrating perforator diameter, midline crossover, and deep-superficial venous communications.

The arterial supply of the long head of biceps tendon: Anatomical study with implications for tendon rupture.

Zones of hypovascularity are thought to exist in several tendons of the shoulder, contributing to localized tendon weakness and subsequent rupture in clinical practice. Although these zones have been demonstrated in many frequently ruptured tendons, the existence of a similar area in the often ruptured long head of biceps (LHB) tendon is largely unknown. Twenty cadaveric upper limb specimens were dissected after injection with either a radio‐opaque lead oxide/milk mixture or India ink, followed by histological sectioning of the tendons. The LHB tendon was consistently supplied via its osteotendinous and musculotendinous junctions by branches of the thoracoacromial and brachial arteries respectively. In two specimens, additional branches from the anterior circumflex humeral artery travelling in a mesotenon vascularized the midsection of tendon. These source arteries divided the LHB tendon into either two or three vascular territories, depending upon the presence of the mesotenon‐derived vascular supply. A zone of hypovascularity was consistently found in the region of the LHB tendon most frequently prone to rupture. This zone covered an area 1.2–3 cm from the tendon origin, extending from midway through the glenohumeral joint to the proximal inter‐tubercular groove. This hypovascular region occurred on the border of two adjacent vascular territories, where reduced caliber choke vessels provide limited arterial supply. While it is probable that the limited arterial supply contributes to the susceptibility of this area to rupture, similar to other tendons the true pathogenesis is likely to be a combination of both vascular and mechanical factors. Clin. Anat. 23:683–692, 2010.

Preserving the neurovascular supply in the Hall-Findlay superomedial pedicle breast reduction: an anatomical study.

BACKGROUND The Hall-Findlay superomedial pedicle technique is widely used for breast reduction, and, despite low complication rates, nipple-areola complex (NAC) necrosis and denervation are still the two most common complications, particularly when resection volumes exceed 600g. An understanding of the anatomy of the neurovascular pedicle of the NAC is paramount in avoiding these complications. METHODS An anatomical study was undertaken on 11 female cadaveric breast specimens (nine fresh and two embalmed). The neurovascular anatomy of the breast was explored through dissection, microdissection, radiographic, computed tomographic, photographic and cross-sectional studies. The superomedial pedicle was mapped out on each specimen, and the course of the relevant nerves and vasculature was identified. RESULTS The arterial supply to the superomedial pedicle was found to originate from a single dominant vessel in each specimen, while the venous drainage was via an extensive branching network. Both vascular patterns traversed the pedicle in a superficial plane. The innervation of the pedicle was via intercostal branches, which coursed extremely superficially in the pedicle. CONCLUSION De-epithelialisation or superficial thinning of the superomedial pedicle for breast reduction is at high risk for complications related to vascular compromise or denervation. Where greater resection is needed, this should be done from the deep surface or the base of the pedicle, contrary to previous descriptions.

Variations in the lymphatic drainage pattern of the head and neck: Further anatomic studies and clinical implications

Background: There is an increasing clinical need for accurate evaluation of the lymphatic anatomy of the head and neck. Methods: Fourteen halves of the superficial tissues of the head and neck and six specimens of the anterior superficial neck tissue from 13 unembalmed human cadavers were studied. Six percent hydrogen peroxide was used to detect the lymphatic vessels by using a surgical microscope. These vessels were then injected with a radio-opaque lead oxide mixture. Each specimen was dissected, photographed, and radiographed to demonstrate lymphatic vessels in the tissue. The final results were then transferred to the computer for analysis. Results: Lymph-collecting vessels were found in three regions of the superficial tissue of the head and neck: the scalp, face, and cervical region. They were dense in the scalp and lateral neck area but sparse in the facial, anterior, and posterior neck. Most vessels in the lateral neck were internodal lymphatics. Two layers of lymphatic vessels were found in the anterior superficial neck tissue coursing in different directions. Conclusions: An actual and accurate lymphatic map of the head and neck lymphatic drainage patterns is presented to upgrade our anatomical knowledge. This map will be of benefit for the clinical management of trauma and malignancies in this region.

The Unfavorable Anatomy of Vastus Lateralis Motor Nerves: A Cause of Donor-site Morbidity after Anterolateral Thigh Flap Harvest

Background: The anterolateral thigh flap is a popular reconstructive option, with a major advantage being its low donor-site morbidity. However, donor-site morbidity following anterolateral thigh flap harvest does occur, with postulated causes including damage to muscle, deep fascia, and the motor nerves to the vastus lateralis. No anatomical studies have yet described the relationship of these motor nerves to the vascular pedicle of the anterolateral thigh flap. Methods: Thirty-six human cadaveric thighs underwent dissection studies, and the innervation of the vastus lateralis and the relationship of the nerves to the descending branch of the lateral circumflex femoral artery were documented. Variations were recorded. Results: The nerve to the vastus lateralis branches extensively before entering the muscle, with four to seven nerves identified per thigh. Two particular variations of the nerve anatomy are uniquely susceptible to damage: where the motor nerve passes through the vascular pedicle itself or passes between perforators supplying the flap. At least one unfavorable variation was present in 28 percent of cases. Conclusions: The nerves innervating the vastus lateralis are intimately related to the vascular pedicle of the anterolateral thigh flap. These nerves may be damaged during flap harvest and may contribute to donor-site morbidity after anterolateral thigh flap surgery.

Preventing venous congestion of the nipple-areola complex: an anatomical guide to preserving essential venous drainage networks.

Background: Venous congestion leading to partial or total nipple necrosis is a relatively uncommon complication of breast reduction and mastopexy procedures but still occurs, particularly in larger reduction procedures. This is largely preventable if the surgeon has an understanding of the venous drainage to the nipple and carefully preserves it. Methods: An anatomical study was undertaken on 16 fresh female cadaveric breast specimens. The venous drainage of the breast was explored through vascular injection, radiographic, and cross-sectional studies. Results: The venous drainage of the breast consists of an extensive network of vessels. The nipple-areola complex is drained by a superficial subareolar ring of veins that drains by means of medial and lateral veins. Laterally, superolateral and inferolateral veins drain into the subclavian veins, whereas medially, two veins drain into the internal mammary veins. An inferior vein drains the inferior quadrant of the breast in the midmammary line. Medially, the veins have a superficial course, whereas laterally, the veins follow a deeper course. Conclusions: The breast contains an extensive venous network. To avoid necrosis of the nipple-areola complex, this venous network should be preserved. The superomedial/medial and inferior pedicles contain the most extensive and more reliable venous drainage patterns.

The morphology of the human lymphatic vessels in the head and neck

Previously little has been written about the morphology of the human lymphatic vessels since Sappey (Sappey [ 1874 ] Anatomie, Physiologie, Pathologie des Vaisseaux Lymphatiques, Paris: Adrien Delahaye) over 100 years ago. There needs to be an accurate re‐evaluation of scientific observations to aid clinical management. Forty‐nine combinations of tissue from the head and neck of 20 unembalmed human cadavers were studied. Six percent hydrogen peroxide was used to find the vessels. They were injected with radio‐opaque mixture, dissected, photographed, and radiographed. Final results were transferred to the computer for analysis. Different sized lymphatic valves were found in the precollecting and collecting lymph vessels, the lymphatic trunks, and ducts. The intervals between the valves were of various lengths. Diverse lymphatic ampullae and diverticula were seen in precollecting and collecting lymph vessels. Initial lymph vessels arose from the dermis, the galea, and the mucosal membrane. The vasculature of the direct and indirect precollecting and collecting lymph vessels, lymphatic trunks, and ducts was recorded. The morphology of the human lymphatic vessels in the head and neck has been described and recorded using radiographs and photographs. Clin. Anat. 23:654–661, 2010.

Predictors of blood transfusion in deep inferior epigastric artery perforator flap breast reconstruction.

Perioperative blood loss during and following breast reconstruction surgery can have substantial impact on free flap survival and patient morbidity. Transfusion rates of up to 95% have been reported following transverse rectus abdominis myocutaneous flap breast reconstruction, with blood loss described as significant in most cases. However, there has been little reported of such requirements in patients undergoing deep inferior epigastric perforator (DIEP) flap breast reconstruction. We present the transfusion requirements of 152 consecutive patients who underwent DIEP flap breast reconstruction, with a view to quantifying transfusion requirements and identifying risk factors for such loss. In this cohort, 80.3% of patients required blood transfusion, with a mean volume of 3.9 U per patient. There was a statistically significant correlation for increased transfusion requirement in patients with preoperative anemia ( P < 0.001) and in bilateral cases ( P < 0.001), but not for cases of immediate reconstruction ( P = 0.72). Although blood loss in breast reconstructive surgery is rarely large enough to be life-threatening, relative anemia does have significant effect on flap survival and patient morbidity. With risk factors for increased transfusion requirements identified in the current study, high-risk patients can be predicted preoperatively.

The postauricular fascia: classification, anatomy, and potential surgical applications

AbstractIn recent times, there has been evolving interest in the fascial structure of the ear, especially in relation to otoplasty techniques. Although the fascial tissues used in these procedures are referred to as “postauricular/retroauricular fascia,” the sparse anatomical studies that exist use this terminology to describe what is the adjacent thicker and more fibrous structure of the superficial temporal area continuous with the mastoid region, rather than the tissue actually used in these procedures which is adherent to the posterior surface of the ear. There are clear clinical differences in the properties of these two structures, and this study set out to identify the anatomical nature of these differences, looking in detail at the anatomy and vascularity of the fascia directly posterior and adherent to the ear itself, highlighting its unique properties, and how it interfaces with the rest of the fascia. We provide a nomenclature to differentiate the fascia adherent to the posterior of the ear (the intrinsic postauricular fascia) from the more fibrous tissues continuous with the scalp fascia (the extrinsic postauricular fascia). Clinical applications for the fascia are suggested based on the vascularity and anatomy described, and our clinical experience.