Axiality and randomness: intention and reality.
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Blood Vessels↗
Biomedical subjects
R D Acland
Publications and source records attributed to R D Acland.
Fundamental laws of vascular anatomy.
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Blood Vessels↗
Refinements in lower extremity free flap surgery.
This chapter recommends numerous factors that are significant refinements in approach and execution of lower extremity free flaps. I encourage a clear conceptual separation between the two essential phases of successful reconstruction of problem wounds: wound preparation and flap transfer. I have found that antibiotic beads maintain the sterility of temporary bony dead space. Due emphasis should be given to preparation of the surgeon, patient, and wound, allowing a nonemergency approach to lower extremity free flap coverage. The surgeon needs to be familiar with a variety of flaps beyond the usual workhorse group. Also, attention should be paid to perioperative warmth and hydration, and vessels affected by posttraumatic vessel disease must be avoided. A positive attitude toward the use of vein grafts whenever necessary is important. I also favor careful planning of the exact size and shape of the flap and length of the vessels along with use of a widely spatulated technique of end-to-side anastomoses.
Anti-Bacterial Agents↗
Aneurysms and the sleeve technique for vessel anastomosis.
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Aneurysm↗
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.
Animals↗
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 tissue's 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.
Acetylcholine↗
Microvascular reconstruction after electrical and deep thermal injury.
Six cases are presented demonstrating uncomplicated primary healing following early microvascular reconstruction for complex electrical and deep thermal injuries. We advocate early preservation of eschar and the prevention of infection with the use of penetrating topical antibacterial agents, removal of the soft-tissue eschar when clinically indicated, and immediate coverage of the undebrided bone through the provision of well-vascularized tissue. Microvascular free tissue transfer should be considered as a primary method of reconstruction for complex electrical or thermal injury whenever clinically feasible. These reconstructive techniques offer an early, reliable means of definitive reconstruction, preserving function, providing uncomplicated healing, and promoting early rehabilitation.
Adult↗
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 musculoaponeurotic 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. We found the deep temporal fascia to be supplied solely by the middle temporal artery, a constant branch of the superficial temporal. The middle temporal artery arises 1 to 3 cm below the upper border of the zygomatic arch, runs always superficial to the arch, and enters the deep temporal fascia immediately above that layer's attachment to the zygomatic arch. If the middle temporal vessels are protected, the two layers of temporal fascia can be raised together as a fully vascularized tissue island. This island can be fashioned as a bilobed or a double-layered flap, depending on the manner of dissection. The potential surgical usefulness of these findings is discussed.
Adult↗
Mandibular reconstruction with microvascular bone transfer. Series of 10 patients.
Mandibular reconstruction with microvascular bone transfer was carried out in 10 patients, including 8 with far advanced intraoral carcinoma and 2 with posttraumatic facial and mandibular defects. Eight patients presented with compromised defects as a result of radiation injury, infection, and scarring. Nine patients experienced primary bony union with complete functional and esthetic reconstruction of the mandible, and two patients eventually received dentures. This technique has resulted in a more effective, more reliable, and earlier reconstruction compared with conventional methods.
Adult↗
Monitoring free vascularised jejunum grafts.
A reliable method of monitoring free vascularised jejunum to the head and neck region has been used in six patients. Preliminarily, the jejunum island flap is subdivided into major and minor segments. Transferred to the neck, the major part is used to reconstruct the oesophageal or pharyngeal defect, while the minor part supplied by the same segmental mesenteric artery is exteriorised through the neck incision. After five days direct monitoring, the marker segment is clamped, tied and excised before suturing the neck wound under local anaesthesia. No failures of the graft occurred. The effectiveness of this technique has surpassed all previously published and unpublished methods.
Aged↗
Distal revascularization and microvascular free tissue transfer: an alternative to amputation in ischemic lesions of the lower extremity.
Most lower extremity amputations result from complications of diabetes and arterio-sclerotic occlusive diseases below the inguinal ligament. Improved limb salvage has been achieved by an aggressive approach to distal revascularization in the severely ischemic lower extremity. There remains, however, a high incidence of amputation resulting from progression of the ulceration or gangrene into deeper and less well-vascularized tissues, such as tendon and bone. Even in the nonischemic extremity, such wounds rarely heal without flap coverage. Microvascular free tissue transfers promote healing by providing coverage with healthy, nondiseased, well-vascularized tissue for these difficult defects. Successful free flap transfer requires a high-pressure recipient inflow vessel. In contrast to individuals with nonarteriosclerotic lesions, many individuals with nonhealing ischemic lesions have no acceptable artery demonstrated on high-resolution angiography to serve as a recipient vessel. Limb salvage has been achieved in four candidates for amputation utilizing distal revascularization followed by free tissue transfer coverage of the ischemic lower leg defects.
Aged↗
Fasciocutaneous vessels of the upper arm.
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Arm↗
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 fascia's 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.
Achilles Tendon↗
Managing the outer limits of reconstruction with microsurgical free tissue transfer.
Six patients had major deficits reconstructed with microsurgical free tissue transfer. In contrast to some opinions that free tissue transfer is a "method of last resort," these patients were selected for microsurgical reconstruction as a method of first choice due to the qualities desired in the reconstruction, the reliability of the technique, and the desire to minimize the functional or aesthetic deficit at the donor site. Microsurgical techniques allowed a reconstruction in these cases that would have been difficult or impossible by conventional techniques, while they markedly improved the quality and reliability of the reconstruction and decreased the donor morbidity. Microsurgical free tissue transfer has been reported to have a success rate of 94% in centers where a significant volume of surgery is done. We believe the continued refinement of microsurgical techniques and their increased application will improve the results of reconstruction in a large category of severe traumatic and cancer defects.
Adult↗
Microvascular free tissue transfer in head and neck and esophageal surgery.
Successful reconstruction for excisional defects of the head and neck and esophagus was accomplished in 93 percent of our patients using microvascular free tissue transfer. Complete failure occurred in 7 percent of the patients. Major defects after head and neck cancer surgery constituted the main indication for use of microvascular free tissue transfer for reconstruction. Ninety-four percent of the patients had undergone an extensive excisional procedure. A wide range of cutaneous, myocutaneous, and osteocutaneous free flaps, as well as free bowel autotransfers were used. Complete failure was three times higher in the previously irradiated patients (4 of 41 patients) compared with nonirradiated patients (1 of 34 patients). Morbidity and mortality rates were consistent with expected ranges in patients who were undergoing major head and neck resection. Donor site complications occurred in 23 percent. Thin flaps are favored for reconstruction of anterior defects in the oral cavity, whereas bulkier flaps are more suitable for deeper defects in the oropharynx and hypopharynx. The advantages are both aesthetic and functional. The free jejunal autograft is considered the reconstructive method of choice for defects produced by laryngopharyngoesophagectomy. Highly developed and sophisticated microsurgical skills continue to be the mainstay of success. The implication of free tissue transfer failure, especially for defects of the upper aerodigestive tract, are impressive in terms of morbidity, mortality, and cost. These considerations limit the application of this method of reconstruction to centers that have sophisticated and productive reconstructive surgeons with microsurgical skills.
Adolescent↗
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.
Aged↗
Free flap neo-vascularisation: case report.
This report records the unusual occurrence of occlusion of the artery of a free flap on the ninth post-operative day. Careful clinical observation strongly suggested that good neo-vascularisation had already occurred at this early date. The pattern of capillary refill suggested that neo-vascularisation originated from the periphery of the recipient site. The decision was made not to re-explore the flap vessel. The flap survived.
Adolescent↗
Scanning electron microscopic study of disturbances in arterial walls following microsurgical needle perforations.
In the canine femoral artery we studied the extent of endothelial and subendothelial damage caused by the passage of seven different commonly used microsurgical needles. Precautions were taken to prevent collapse and risk of early vascular trauma prior to needle perforations and fixation for SEM. Since surgical anastomosing procedures are done with grafted vascular segments maintained at normal length and Omm Hg pressure, prior to clamp removal and redilation, SEM specimens were prepared under similar conditions. Under normal vessel tension, needles were passed through the vessel thus producing an entry and exit wound. Vascular templates were constructed with sagittally sectioned arteries pinned to cardboard mounts to display the needle puncture sites and prevent vascular shrinkage. Mounted vessels were maintained in oxygenated lactate-ringers at body temperature prior to glutaraldehyde fixation. Intimal folds consisting of normal undislodged endothelial cells were seen in all areas except at needle puncture sites. Needles produced varying degrees of gross damage at entry and exit wounds. Most taper point needles tend to spread apart intimal folds while some cutting edge needles slice through endothelial cells. Cutting edge needles tend to tear off endothelial cells surrounding the wound exposing the internal elastic lamina. We have observed intact cytoplasmic extensions between endothelial cells of adjacent intimal folds remote from the wound. These extensions appear broken in the vicinity of the wound. At certain lesion sites smooth muscle cells are regularly spaced between intact and cut elastic fibers. SEM provides ultrastructural information of mechanical disturbances to the walls of arteries caused by common microsurgical needles.
Animals↗