The arterial supply of the cervical and thoracic spinal muscles and overlying skin: Anatomical study with implications for surgical wound complications.

Postoperative spinal wound dehiscence is a significant complication following the posterior midline approach. It is postulated that this approach disrupts the vasculature supplying the paraspinal muscles and overlying skin. Although the spinal vasculature has been investigated previously, the smaller arterioles have not been described in the context of the posterior midline approach. Eight cadaveric neck and posterior torso specimens were dissected after injection with a radio-opaque lead oxide mixture and subsequent radiographs taken were analyzed. The deep cervical, vertebral, superficial cervical, and occipital arteries consistently supplied the cervical paraspinal muscles. The latter two arteries also vascularized the overlying skin. The deep cervical arteries were found to be located lateral to the C3 to C6 vertebrae, vulnerable to damage with the posterior approach. In the thoracic region, the superior and posterior intercostal arteries consistently supplied the spinal muscles. In all specimens, two small anastomotic vessels posterior to the laminae were found connecting the intercostal artery perforators. Both the arterial perforators and their anastomotic channels were situated in the surgical field and susceptible to damage with the posterior approach. It is likely that the disruption in spinal vasculature contributes to the multifactorial problem of wound dehiscence with the posterior midline approach.

Arterial supply of the tendinous rotator cuff insertions: an anatomical study.

BACKGROUND: Confirming the presence of arteries crossing the osteotendinous junctions (OTJs) of the rotator cuff may explain why rates of avascular necrosis (AVN) of the humeral head vary between three- and four-part proximal humeral fractures. It is hypothesized that the humeral head remains better vascularized in three-part fractures because one tuberosity with its inserting rotator cuff tendons is still attached to the articular fragment and supplying it with blood. METHODS: Eighty rotator cuff tendons from 20 shoulder girdles of cadavers aged 68-94 years were studied. In six shoulder girdles, the anterior circumflex humeral artery and posterior circumflex humeral artery (PCHA) were injected with ink, and the extra- and intraosseous courses of the vasculature were dissected until the OTJs of the rotator cuff. RESULTS: The rotator cuff insertions received an arterial supply across their OTJs in 50% of cases (75% in supraspinatus, 67% in subscapularis, 33% in infraspinatus and 20% in teres minor). Supraspinatus and subscapularis insertions were vascularized by the arcuate artery, while the insertions of infraspinatus and teres minor were supplied by an unnamed terminal branch of the PCHA. This was named 'posterolateral artery'. CONCLUSION: The presence of arteries crossing the OTJs of the rotator cuff, as well as the differences in the frequency arteries crossed the OTJs of individual rotator cuff tendons, may help explain why there is a lower rate of AVN of the humeral head in thee-part, compared with four-part proximal humeral fractures.

New approach to the study of intraosseous vasculature.

BACKGROUND: The study of intraosseous vasculature has always been challenging due to the hard, calcified structure of bone. Techniques used to study intraosseous vasculature usually involve diaphanization with a Spalteholz technique, followed by X-ray imaging to display the radio contrast-injected blood vessels. These techniques produce results with fine detail when successfully executed. However, high failure rates and the extensive length of time required to perform these techniques are drawbacks. This paper describes a faster, alternative method for the study of intraosseous vasculature. METHOD: Five embalmed and two fresh shoulder girdles were harvested from six cadavers. Cannulas were inserted into the origins of the anterior (ACHA) and posterior (PCHA) circumflex humeral arteries and injected with ink diluted in water or 6% hydrogen peroxide. The arteries and their branches were dissected until they entered their respective bony foraminae. A hammer, chisel, bone nibbler and mounted needles were used to follow the intraosseous course of these arteries and their branches. RESULTS: The intraosseous vasculature was seen in all specimens. The branches of the main nutrient artery to the proximal humerus were followed until they reached articular cartilage or crossed cortical bone again to enter the rotator cuff tendons. DISCUSSION: An innovative, new approach to the study of intraosseous vasculature with direct visualization of the intraosseous arteries of the proximal humerus is described.

The gracilis myocutaneous free flap: a quantitative analysis of the fasciocutaneous blood supply and implications for autologous breast reconstruction.

BACKGROUND: Mastectomies are one of the most common surgical procedures in women of the developed world. The gracilis myocutaneous flap is favoured by many reconstructive surgeons due to the donor site profile and speed of dissection. The distal component of the longitudinal skin paddle of the gracilis myocutaneous flap is unreliable. This study quantifies the fasciocutaneous vascular territories of the gracilis flap and offers the potential to reconstruct breasts of all sizes. METHODS: Twenty-seven human cadaver dissections were performed and injected using lead oxide into the gracilis vascular pedicles, followed by radiographic studies to identify the muscular and fasciocutaneous perforator patterns. The vascular territories and choke zones were characterized quantitatively using the 'Lymphatic Vessel Analysis Protocol' (LVAP) plug-in for Image J® software. RESULTS: We found a step-wise decrease in the average vessel density from the upper to middle and lower thirds of both the gracilis muscle and the overlying skin paddle with a significantly higher average vessel density in the skin compared to the muscle. The average vessel width was greater in the muscle. Distal to the main pedicle, there were either one (7/27 cases), two (14/27 cases) or three (6/27 cases) minor pedicles. The gracilis angiosome was T-shaped and the maximum cutaneous vascular territory for the main and first minor pedicle was 35 × 19 cm and 34 × 10 cm, respectively. CONCLUSION: Our findings support the concept that small volume breast reconstructions can be performed on suitable patients, based on septocutaneous perforators from the minor pedicle without the need to harvest any muscle, further reducing donor site morbidity. For large reconstructions, if a 'T' or tri-lobed flap with an extended vertical component is needed, it is important to establish if three territories are present. Flap reliability and size may be optimized following computed tomographic angiography and surgical delay.

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.

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.

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.

Lymphatic drainage of the external ear.

BACKGROUND: Lymphoscintigraphy reveals inconsistencies in our knowledge of the lymphatic anatomy of the external ear. METHODS: Fifteen external ears from 9 unembalmed human cadavers were studied. Six percent hydrogen peroxide was used to find the lymphatic vessels using a surgical microscope. They were injected with a radio-opaque mixture, dissected, photographed, and radiographed to demonstrate lymphatic vessels in the tissue. Final results were transferred to the computer for analysis. RESULTS: Four groups of lymph collecting vessels were found. The anterior branch, in all specimens, drained directly or indirectly (having merged with a vessel descending from the scalp) into the preauricular lymph nodes. The superior, middle, and inferior (lobule) branches drained to their multiple first tier lymph nodes. CONCLUSION: An accurate lymphatic map of the external ear is described to upgrade our anatomic knowledge. It will be of benefit for the clinical management of malignancies in this region.

Alternative lymphatic drainage routes from the lateral heel to the inguinal lymph nodes: anatomic study and clinical implications.

BACKGROUND: The route of lymphatic drainage from the heel to the inguinal lymph nodes is required to be accurately evaluated for clinical needs. METHODS: Seven lower limbs from four unembalmed human cadavers were studied. Under a surgical microscope, 6% hydrogen peroxide was used to detect the lymphatic vessel on the lateral side of the heel. The vessel was then injected with a radio-opaque lead oxide mixture. The vessel was traced, photographed and radiographed to demonstrate the lymphatic pathways from the lateral heel to the inguinal lymph nodes. The final results were transferred to the computer for image analysis. RESULTS: The lymph collecting vessel arising from the skin of the fossa between the lateral malleolus and the Achilles tendon ran along the posterolateral side of the leg, deep to the superficial fascia. From the popliteal fossa to the inguinal lymph nodes, three lymphatic routes were found: (i) via the superficial tissue of the medial side of the thigh; (ii) running with the superficial femoral blood vessels; (iii) running between the sciatic nerve and the profunda femoral vessels. The number and type of lymph nodes found in the popliteal fossa and femoral triangle were different from person to person. CONCLUSION: Actual and accurate lymphatic routes from the skin above the posterolateral heel to the inguinal lymph nodes have been described. This information upgrades our anatomical knowledge and the results will be of benefit for the clinical management of trauma and malignancies in the lower limb.

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.

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.

Blood supply to the lymphatic vessels in the leg: an incidental finding.

There are no reports or images of the blood supply to the lymphatic vessels. One lower limb of an unembalmed human cadaver was studied. Hydrogen peroxide (6%) was applied to find the lymphatic vessels by using a surgical microscope. The vessels were injected with a radio-opaque mixture and dissected. During the dissection, several sites of paralymphatics arteriole nutrient (PAN) vessels were found in close proximity to collecting lymphatic vessels in the medial aspect of the leg. The caliber of the lymphatic vessels was about 1 mm. The caliber of PAN vessels was <0.1 mm. The blood vessels were seen running along the lymphatic vessels. Some of them crossing the lymphatics and supplying the fatty tissue nearby and some running parallel on the lymph vessel walls. Histology sections show different-sized PAN vessels containing blood cells situated close to the lymphatic wall and within the lymphatic vessel wall. PAN vessels have been found and described. It will upgrade our anatomical knowledge and also be of benefit for medical and/or scientific research.

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 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.

The use of clinical contrast media for lymphangiography in cadaveric studies.

BACKGROUND: Radiographic contrast media have not been previously used in human lymphatic cadaver studies. As these will have further clinical applications, we sought to investigate their use in this role. METHODS: Both lower legs from an unembalmed human cadaver were studied. We used hydrogen peroxide to identify the lymphatics of the dorsum of the foot, and a single lymphatic was microsurgically injected with 1 ml of 76% 'Urografin.' A series of radiographs were taken 1 min after injection and for 2.5 h until the Urografin vanished. Images were digitalized for analysis. RESULTS: The series of lymphangiograms generated showed the size, location, and course of the lymphatics in the leg. Over time, the density of the iodinated contrast in the lymphatic vessels reduced and disappeared completely after 2.5 hours postinjection. A 'digitally subtracted' image provided a clear and high-contrast lymphangiogram. The lymphatic network identified was shown to diverge and converge twice as it coursed proximally up the limb. CONCLUSION: Urografin, a clinical radiographic contrast medium, was shown to lose contrast density 2.5 h following cadaveric intralymphatic injection. The use of a new technique, that of 'digital subtraction lymphangiography,' was able to demonstrate the lymphatic vessel pathways clearly, and is a useful technique for cadaveric lymphatic studies.