Robert D. Acland

The Lateral Upper Arm Flap: Anatomy and Clinical Applications

There is a highly dependable free flap donor site of moderate size on the posterolateral aspect of the distal upper arm. The area is supplied by the posterior radial collateral artery, a direct continuation of the profunda brachii. The flap area is supplied by a direct cutaneous nerve. It can be raised on its own, with underlying tendon, with bone, or with fascia only. This article describes our findings in 32 cadaver dissections and in 23 clinical cases.

Experience with the temporoparietal fascial free flap

The temporoparietal fascia is an ideal tissue source for free transfer to distant sites where ultrathin coverage is either desirable or mandatory. The fascias dependable vascular anatomy facilitates the technical aspects of microvascular transfer by means of its large vessels, ample pedicle, and ability to be grafted on either side. Furthermore, this highly vascular tissue is available in surprisingly large quantities, and its donor scar is hidden in the hair. The authors have found this flap useful (1) in covering exposed bone and tendon without adding unwanted bulk, (2) in providing thin flap coverage or lining in major facial reconstruction, (3) in covering vital structures such as exposed nerves and vessels, (4) in providing neovascularity both as a recipient graft bed and for control of chronic infection, and (5) in reestablishing gliding-tendon mechanisms. The authors have successfully employed this free flap in 15 cases which involved deformities of the ankle, foot, Achilles tendon, forearm, hand, nose, and contralateral ear and scalp. Seven cases are utilized to illustrate the broad application of this unique and versatile free flap.

Surgical anatomy and blood supply of the fascial layers of the temporal region.

In 15 fresh cadavers (30 sides), we studied the two layers of fascia in the temporal region, with particular regard to their blood supply and to their usefulness– together or separately–as microvascular free-tissue autografts. The superficial temporal fascia (temporoparietal fascia, epicranial aponeurosis) lies immediately deep to the hair follicles. It is part of the subcutaneous musculo-aponeurotic system and is continuous in all directions with other structures belonging to that layer–including the galea above and the SMAS layer of the face below. The deep temporal fascia (temporalis fascia, investing fascia of temporalis) is separated from the superficial fascia by an avascular plane of loose areolar tissue. It completely invests the superficial aspect of the temporalis muscle down to (but not beyond) the zygomatic arch. It is firmly attached to periosteum all around the margin of the muscles. Below it is attached to the upper border of the zygomatic arch.

Revascularized periosteal grafts--a new method to produce functional new bone without bone grafting.

In the replacement of bone lost from trauma, tumor, or infection, and also for the correction of certain congenital abnormalities, conventional bone grafting is not always successful. The survival of these grafts, as such or as materials for new bone, is often unpredictable, and they may become resorbed.1,2 Recently, the microvascular transfer of living bone has been performed—but there are strict limitations on thé size and configuration of such free vascularized grafts.3, 4 We will discuss an alternative to bone grafting—vascularized periosteal grafts— by means of which new bone may be intentionally formed.

The histopathology of small arteries following experimental microvascular anastomosis.

We studied the histopathological changes present at various intervals after microsurgical anastomoses in the femoral arteries of 30 rats. The principal findings were (1) widespread loss of intima, (2) widespread necrosis of media, and (3) dehiscence of sutures. The possible causes for these, and their possible significance, are discussed.

Vascular isolation of the rat cremaster muscle

The vascular supply to the rat cremaster muscle was completely isolated to provide a microvascular preparation with a controllable blood flow. The anatomy of the cremaster vascular supply and the surgical approach to isolate the cremaster muscle on its neurovascular pedicle are described. The functional integrity of this isolated cremaster preparation was tested using intravital video microscopy to evaluate the tissues response to vasoactive agents and to peripheral nerve stimulation. The isolated cremaster muscle was positioned in situ in a controlled tissue bath and concentration response curves to the topical application of norepinephrine (NE) and acetylcholine (Ach) were determined. Vasoconstriction elicited by the topical application of NE or by stimulation of the genitofemoral nerve trunk was similar for both the isolated and standard cremaster preparations. Application of 10(-5) M Ach caused maximal vasodilation equal to that produced by 10(-3) M papaverine in both preparations. In summary, the isolated cremaster muscle of the rat is an acceptable model of a skeletal muscle microcirculation which can be used to investigate microvascular function when precise monitoring or control of perfusion to the entire muscle is needed.

Prevention of thrombosis in microvascular surgery by the use of magnesium sulphate

Summary A new technique has been developed for the prevention of thrombosis at suture anastomoses in small blood vessels. The technique consists of irrigating the outside of the anastomosed vessel with isotonic magnesium sulphate solution throughout the first 20 minutes of blood flow. Use of this technique gave 90 per cent success in end-to-end anastomosis of arteries 0·5 mm. in diameter. A description of the technique is preceded by an account of the behaviour of platelet thrombi at sites of surgical injury, and a brief account of the physiology of platelets.

Direct in Vivo Observations of Embolic Events in the Microcirculation Distal to a Small-vessel Anastomosis

This study was done to determine whether microemboli are produced by an arterial anastomosis. Direct in vivo observations were made in an isolated microcirculatory bed lying directly downstream from a newly made anastomosis. The tissue used was the isolated rat cremaster muscle, a new experimental model. The vessel anastomosed was the external iliac artery. Following anastomosis, microemboli were clearly observed in eight of eight animals during the first 30 minutes after clamp release. Embolic events were sometimes of impressive magnitude and in one case were associated with cessation of blood flow throughout the preparation. No microemboli were observed in eight of eight animals subjected only to dissection of the cremaster, nor were any observed in eight of eight animals in which the isolated cremaster was subjected only to 2 hours of clamp ischemia. These findings may be significant in explaining perturbations to blood flow following free-tissue transfer and instances of partial tissue necrosis following apparently successful arterial repair. These findings also identify an important factor (microemboli) to be considered in research on reperfusion injury.

Inframammary fold: a histologic reappraisal.

The inframammary fold is a defining element in the shape and structure of the female breast. It should be preserved whenever possible in ablative procedures and recreated accurately when the breast is reconstructed after mastectomy. To date, no accurate anatomic description of this essential structure exists. Previous studies have suggested that the fold is produced by a supporting ligament running from the dermis in the fold region to a variety of locations on the rib cage. This clinic’s experience with mastectomy, augmentation mammaplasty, and breast reconstruction does not support the existence of a ligamentous structure. To define the structure of the inframammary fold, 10 female and 2 male cadavers were studied. The anterior chest wall was removed en bloc and frozen in orthostatic position. Parasagittal sections were made of the inframammary fold with the chest wall intact. After decalcification of the ribs and routine histologic preparation, thin sections were stained with Gomori’s trichrome. On light microscopic examination, no demonstrable ligamentous structure of dense regular connective tissue could be identified in the fold region in any of the 12 specimens. Superficial and deep fascial layers were uniformly observed anterior to the pectoralis major and serratus anterior muscles. The superficial fascia was connected to the dermis in the fold region in a variety of configurations. In some cases, the deep fascia fused with the superficial fascia and dermis at the fold level. In other cases, bundles of collagen fibers arising from the superficial fascial layer were found to insert into the dermis at the inframammary fold, slightly inferior to it, or both. These bundles were observed consistently in sections from the sternum to the middle axillary line. They were distinct from Cooper’s suspensory ligaments, which are seen more superiorly in the glandular tissue. (Plast. Reconstr. Surg. 105: 549, 2000.)

lack of Nitric Oxide Contributes to Vasospasm during Ischemia/reperfusion Injury

&NA; Vasospasm can be a complication after free tissue transfer and replant operations. Recent studies suggest that vasospasm may be due to endothelium dysfunction, resulting in impairment of nitric oxide production. The present experiment was designed to investigate acute responses of the microcirculation of skeletal muscle to local interarterial infusion of sodium nitroprusside (a direct donor of nitric oxide and thus an endothelium‐independent vasodilator) or acetylcholine chloride (which stimulates endothelium release of endogenous nitric oxide) during reperfusion after 4 hours of warm ischemia. Male Sprague‐Dawley rats, each weighing 100 to 120 gm, were anesthetized with sodium pentobarbitone and were surgically prepared with vascular isolated and denervated cremaster muscles that were subjected to 4 hours warm ischemia and 2 hours of reperfusion. Sodium nitroprusside (10−3 M), acetylcholine chloride (10−4 M), or normal saline (eight rats for each group) were administered by local infusion (0.1 ml/hour) through the femoral artery into the natural blood flow of the cremaster. The arterial tree in the cremaster was observed and arteriole diameters (A1‐A4) were measured using intravital microscopy. The number of arteriole branches having temporary stoppage of flow were counted in each cremaster. The results from this study show that local infusion of sodium nitroprusside, but not acetylcholine chloride, prevents ischemia/reperfusion vasoconstriction in A3 and A4 arterioles and thus improves microvascular blood flow. Generalized vasoconstriction caused by topically applied norepinephrine (10−6 M) to sham ischemia cremasters could be completely reversed by the local infusion of 10−4 M acetylcholine chloride. These results indicate that vasospasm after ischemia/reperfusion may be related to temporary endothelial cell dysfunction, resulting in the inability to produce sufficient nitric oxide during early reperfusion. Vascular smooth muscle, however, is responsive to locally administered sodium nitroprusside infusion (which is thought to provide exogenous nitric oxide).