Pharmacologic manipulation of the microcirculation in cutaneous and myocutaneous flaps in pigs

The vascular effects of isoxsuprine, diazoxide, and isoproterenol were studied in arterial buttock flaps and latissimus dorsi myocutaneous flaps in pigs. Capillary blood flow to the skin and muscle of these flaps was measured by the radioactive microsphere (15-mu diameter) technique 6 hours postoperatively under pentobarbital anesthesia. It was observed that isoproterenol, a beta-adrenergic receptor agonist, was not effective in augmentation of skin blood flow in the arterial buttock flaps. However, isoproterenol significantly increased capillary blood flow to the arterialized portion of latissimus dorsi myocutaneous flaps compared with controls. Isoxsuprine and diazoxide (vascular smooth muscle relaxants) significantly (p less than 0.05) increased total capillary blood flow to the skin of arterial buttock flaps and to the skin and muscle of the latissimus dorsi myocutaneous flaps. However, the increase in capillary blood flow occurred mainly in the arterialized portion of these flaps. The capillary blood flow, which was supplied by the small arteries in the distal portion of the arterial buttock and latissimus dorsi flaps, was not increased by treatment with isoxsuprine or diazoxide. Therefore, there was also no increase in the maximum distance of capillary blood flow from the pedicle to the distal end of the flaps. These observations led us to hypothesize that different sizes (diameters) of arteries in the skin and muscle have different reactivity (or sensitivity) to vasodilatory drugs. In the present experiment, the large dominant artery of the arterial buttock and latissimus dorsi flaps responded to isoxsuprine or diazoxide (vascular smooth-muscle relaxants), resulting in an increase in blood supply to the capillaries in the proximal portion of the flaps. On the other hand, the small arteries in the distal portion (random portion) of these flaps were not sensitive to isoxsuprine or diazoxide. Therefore vasodilation did not occur, and there was no increase in blood supply to the capillaries in the distal portion of arterial buttock and latissimus dorsi flaps. This explanation also lent support to our previous report that treatment with isoxsuprine did not augment skin viability in the distal portion of arterial buttock and latissimus dorsi flaps. It is suggested that research in pharmacologic manipulation of skin blood flow and viability in skin flap surgery should emphasize the sensitivity of small arteries to various drug actions.(ABSTRACT TRUNCATED AT 400 WORDS)     

The anatomy of the subscapular artery and its effects on flap design in the rabbit

The course of the subscapular artery was studied in 20 rabbits. Its course was constant, giving two branches to the latissimus dorsi muscle after which the vessel sent a branch (S1) that perforated the panniculus carnosus to supply a large territory of skin. In a separate experiment, the contribution of the S1 branch to the viability of the rabbit latissimus dorsi musculocutaneous flap was evaluated. From this experiment it can be concluded that, first, it is possible in a rabbit to elevate a large skin flap based solely on a muscle perforator (S1), which survives completely. Second, in the rabbit latissimus dorsi musculocutaneous flap, S1 is the major blood supply to the skin component. Damage to it severely diminishes skin flap survival, even if the vascular supply to the underlying muscle is completely intact.     

Blood flow after warm ischemia in island flaps: latissimus dorsi myocutaneous and epigastric flaps in the dog

Island latissimus dorsi myocutaneous flaps are compared with island epigastric flaps in the dog in terms of their ability to reestablish blood flow and maintain tissue viability after increasing periods of warm ischemia. Blood flow in the vascular pedicles of the flaps was measured after one minute to ten hours of ischemia with an electromagnetic flowmeter. The histological condition of the cutaneous and muscular portions of these flaps was examined with light microscopy at the end of the ischemia period and after reflow. In comparison to the epigastric flap, the latissimus dorsi myocutaneous flap had a greater baseline flow before ischemia, a greater rise in flow above baseline (reactive flow) after ischemia, and an equal resistance to ischemia in terms of preservation of reactive hyperemia, recovery of nutritive flow to the skin, degree of histological changes in the skin, and patency of the vascular pedicle. Despite the vulnerability of the muscular component of the latissimus dorsi myocutaneous flap to ischemia, the muscle perforators remain patent and the dermis survived even after eight hours of warm ischemia.     

A rat musculocutaneous flap model: the biceps femoris musculocutaneous flap

The purpose of this study was to describe a new musculocutaneous flap model in the rat. A total of 25 Wistar rats weighing 200 to 280 g were used in this experiment. In 15 rats, the vascular anatomy of the biceps femoris muscle and the cutaneous blood supply of its overlying posterior thigh skin were studied by anatomic dissection, dye injection, and microangiography using 5 rats in each group. The anatomic studies revealed that the main axial vessel supplying the biceps femoris muscle was the caudal femoral branch of the popliteal vessels. The posterior thigh skin overlying the biceps femoris muscle received a consistent musculocutaneous perforator at the center of the mid-posterior line of the posterior thigh. Based on the caudal femoral-popliteal vascular pedicle, the biceps femoris musculocutaneous flap was created in the rat, comprised of the whole muscle and its overlying posterior thigh skin. The skin paddle was designed as an ellipse with its longitudinal axis paralleling that of the extremity, generally measuring 4 x 2 cm. Island flaps were raised as described and replaced either in situ (N = 5) or transposed to a sacral defect (N = 5). Results showed that the cutaneous islands of all the flaps survived completely. Tetrazolium blue stain used to indicate muscle survival revealed that the average muscle viability was 86.7+/-3.4%. The authors conclude that the biceps femoris musculocutaneous flap is a reliable and true musculocutaneous flap model for future biological and pharmacological studies. It offers the following advantages: It has a consistent vascular pedicle and a musculocutaneous perforator, it supports a relatively large skin island, and there is no risk of autocannibalization of the flap because the flap is located dorsally.     

The transverse gracilis musculocutaneous flap.

Through detailed anatomical study and latex injection of 24 cadaver legs, the blood supply to the skin overlying the gracilis muscle was examined. The proximal pedicle entered the gracilis muscle 10 +/- 2 cm below the pubic tubercle. The dissections identified both septocutaneous and musculocutaneous perforators from the proximal gracilis pedicle. These branches had a pronounced tendency to travel in a transverse direction, supplying the cutaneous territory over the adductor longus and sartorius anteriorly and extending for > 5 cm beyond the posterior margin of the gracilis muscle. This information led to a "new" transverse design of the gracilis musculocutaneous flap, such that the vascular perforators are invariably included in the cutaneous portion of the flap. In contrast, the traditional design, because of skin mobility, may allow elevation outside the skin territory of the muscle perforators.     

Latissimus dorsi muscle and its short perforator-based skin compound free flap

Some authors have described the latissimus dorsi muscle and its short perforator-based skin compound flap based on the same thoracodorsal vessels. This flap procedure involves separating the skin island from the underlying latissimus dorsi muscle and rotating the skin island over the musculocutaneous perforator emerging from the latissimus dorsi muscle. As with all surgical procedures, there are various advantages and disadvantages. However, to the best of the authors' knowledge, there are no reports on the use of the flap in a consecutive series.Between 1997 and 2005, the flap was used to reconstruct below-knee structures in 26 patients (23 males and 3 females) by the 2 senior authors at the Chonnam National University Medical School. The clinical outcomes of this procedure were evaluated.Satisfactory results were obtained in most patients. However, there were 2 marginal necroses in the excessively large skin flaps, 1 partial necrosis over the distal edge of a skin flap, and 1 total flap failure caused by infection. The marginally and partially necrotized skin flaps were treated successfully with split-thickness skin grafts. However, another flap procedure was required to cover the defect in the case of flap failure. The donor sites were closed primarily in all patients, and the skin flaps were rotated between 40 degrees and 180 degrees. This flap allows the surface of the latissimus dorsi musculocutaneous flap to be expanded without additional donor morbidity. In addition, the flap procedure is safe and easy to perform. Moreover, the flap provides sufficient flexibility, even though it has less independent flap mobility than the chimeric flap. Therefore, the flap may be a convenient and reliable alternative for the reconstruction of large and irregular-shaped wounds.     

Comparison of bacterial inoculation and transcutaneous oxygen tension in the rabbit S1 perforator and latissimus dorsi musculocutaneous flaps

Muscle and musculocutaneous flaps have been used reliably in reconstruction of soft-tissue defects for many years. Previous experimental studies have shown musculocutaneous flaps to be superior to the random pattern and fasciocutaneous flaps in the management of infected wounds. Over the past decade, perforator flaps have gained acceptance as alternative methods of reconstruction in the clinical setting that can decrease donor-site morbidity and hospital stay, and increase patient satisfaction. The authors theorized that perforator flaps may be able to handle infected wounds better than random pattern and fasciocutaneous flaps because their blood supply is essentially the same as many of their musculocutaneous counterparts. The goal of this study was to compare the S1 perforator-based skin flap and latissimus dorsi musculocutaneous flap in the dorsal flank of the rabbit with the introduction of bacteria to simulate both superficial and deep wound infection. Measurements of oxygen tension and regional perfusion index were performed on both types of flaps to ascertain their viability and capacity to heal. The authors found no statistical significance between latissimus dorsi musculocutaneous and S1 perforator flaps in the rabbit with respect to superficial and deep wound infections. The regional perfusion index was calculated for postoperative days 1, 2, and 4. No statistically significant difference between the two flaps using the regional perfusion index could be identified. Additionally, regional perfusion for both types of flaps was greater than 0.6, indicating that their capacity to heal wounds is similar.     

Extended latissimus dorsi musculocutaneous flaps for extremely wide cervical skin defects involving the cervical esophagus.

Two cases using island distally and anteriorly extended latissimus dorsi musculocutaneous flaps for one-stage reconstruction of pharyngoesophageal defects of the entire front of the neck are reported. The advantage of this flap is its extremely large skin territory, which provides a reliable vascular supply. This flap is suitable for extremely wide cervical defects where the recipient vessels are damaged after severe infection and irradiation.     

One-stage reconstruction of facial paralysis associated with skin/soft tissue defects using latissimus dorsi compound flap.

Neurovascular free muscle transfer is now the mainstay for smile reconstruction in the treatment of established facial paralysis. Since facial paralysis due to ablative surgery or some specific disease sometimes accompanies defects of the facial skin and soft tissue, simultaneous reconstruction of defective tissues with facial reanimation is required. The present paper reports results for 16 patients who underwent reconstruction by simultaneous soft tissue flap transfer with latissimus dorsi muscle for smile reconstruction of the paralysed face. Soft tissue flaps comprised skin paddle overlying the latissimus dorsi muscle (n=6), serratus anterior musculocutaneous flap (n=5), serratus anterior muscle flap (n=2), and latissimus dorsi perforator-based flap with a small muscle cuff (n=3). The latissimus dorsi muscle can be elevated as a compound flap of various types, and thus offers the best option as a donor muscle for facial reanimation when soft tissue defects require simultaneous reconstruction.     

Pre-expanded Muscle-sparing Latissimus Dorsi Flaps for Reconstruction of Severe Scar Contractures on the Anterior Chest

ObjectiveTo investigate the utility of pre-expanded muscle-sparing latissimus dorsi flaps in the reconstruction of deformities secondary to severe scar contractures on the anterior chest.MethodsThe function of the latissimus dorsi was preserved with blood supply from the main or lateral branch of the thoracodorsal artery. The entire treatment period was divided into two stages, during which segmental latissimus dorsi flaps were pre-expanded in stage I and anterior chest scar deformities were reconstructed in stage II.During stage I, the musculocutaneous perforators arising from the lateral branch of the thoracodorsal artery were determined by ultrasound preoperatively; the flap design included the anterior segment of the latissimus dorsi supplied by the musculocutaneous perforators from the lateral branch; and a tissue expander was placed following flap dissection and then infused with saline intermittently for 4–6 months.In stage II, the chest scars were excised, and breast tissues were repositioned; the continuity of the medial branch of the thoracodorsal nerve to the muscle was preserved when reconstruction was performed using the segmental latissimus dorsi flaps supplied by the main or lateral branch of the thoracodorsal artery.ResultsFrom October 2010 to October 2019, 21 patients (on 24 sides) underwent reconstructive procedures for extensive scar contractures on the anterior chest. All flaps survived, and their donor sites were sutured directly. During a follow-up of 3 months to 8 years, the flaps became soft and exhibited color similar to that of the adjacent tissues. The limited neck and shoulder movements improved, and postoperatively, all female patients were satisfied with the shape of their breasts. Additionally, neither apparent weakening on the adduction, internal rotation, or extension strength of the shoulder joint on the affected side nor marked depression deformity in the back was observed.ConclusionPre-expanded muscle-sparing latissimus dorsi flaps with blood supply from the main or lateral branch of the thoracodorsal artery proved to be a desirable option for the reconstruction of extensive scar contractures on the anterior chest.     

应用背阔肌岛状肌皮瓣修复烧伤后乳房畸形

目的 介绍应用背阔肌岛状肌皮瓣修复前胸壁烧伤后所致乳房瘢痕挛缩畸形的临床效果.方法 应用扩张或未扩张的背阔肌岛状肌皮瓣修复烧伤后乳房瘢痕、部分缺损畸形,其中轻、中度烧伤后乳房缺失2例,采用背阔肌岛状肌皮瓣修复重度乳房缺失5例,采用扩张的背阔肌岛状肌皮瓣修复.结果 共治疗7例,术后肌皮瓣完全成活,乳房形态明显改善,无肌皮瓣坏死、背部伤口感染、裂开及肩部功能障碍等并发症发生.供区无明显后遗畸形及功能障碍.结论 背阔肌岛状肌皮瓣血运良好,操作简便易行,是修复烧伤乳房畸形的较好方法.     

Reconstruction of large soft tissue defects of the lower torso with rectus abdominis musculocutaneous flaps

Summary Seven large defects of the lower torso were closed with rectus abdominis musculocutaneous flaps: two large roin defects, three abdominal wall defects, and two open lateral pelvic wounds. Five of the flaps were inferiorly based and two superiorly based. The donor site was closed primarily unless a large skin paddle was taken, in which case the donor site was skin grafted. The central location, excellent blood supply (superior and inferior epigastric arteries plus abundant cutaneous perforators), and length and thickness of the rectus abdominis muscle make it a versatile flap for abdominal wall and lower torso defects.     

Reconstruction of complex thoracic defects with myocutaneous and muscle flaps. Applications of new flap refinements

This report describes reconstructions of complex thoracic defects with myocutaneous and muscle flaps that were modified by several recent refinements of flap design. These refinements comprise a second generation of myocutaneous and muscle flaps, which have substantially increased versatility and extended applications, as compared with the originally described flaps. These refinements include the following: (1) segmentally split latissimus dorsi and pectoralis major flaps, which transfer only one muscle segment as the flap and leave other segments of the same muscle in situ to preserve motor function; (2) pectoralis major fasciocutaneous flaps, which are extended by abdominal skin and fascia to provide longer, larger flaps; (3) reversed pectoralis major and latissimus dorsi flaps, which are supplied by secondary, distal vascular pedicles that permit flap use when the primary vascular supply is interrupted; and (4) island vascular pedicle muscle flaps, which allow intercostal passage for reconstruction of intrathoracic defects and cavities. The anatomic bases for these flap refinements are described, and the advantages provided are discussed.     

Peripheral neovascularisation of muscle and musculocutaneous flaps

The collateral vascularisation of muscle flaps covered by a skin graft and of musculocutaneous island flaps was studied in a pig model using the latissimus dorsi muscle. Vascular ingrowth from the underlying bed was stopped by using silastic sheeting. The time taken for peripheral vascularisation of flaps to render them independent of pedicle blood supply was studied. In addition microangiograms were performed at the time of sacrifice of the animals (4 weeks postop.) to give a visual conception of the sites and sizes of new vessel growth at the periphery of the flaps. Results showed significant delay, in muscle flaps with skin grafts reset onto a poor bed, in obtaining a blood supply independent of the pedicle supply.     

带蒂背阔肌皮瓣修复锁骨区恶性肿瘤切除术后皮肤软组织缺损

目的 探讨带蒂背阔肌皮瓣在修复锁骨区恶性肿瘤切除术后皮肤软组织巨大缺损的疗效.方法 对2015年11月-2018年1月收治的9例锁骨区恶性肿瘤患者,术前常规穿刺病检,病检结果证实后手术扩大切除,切除后所形成的巨大缺损创面采用带蒂背阔肌皮瓣进行修复.结果 术后经15～24个月随访,皮瓣全部成活,供区均一期愈合.近、远期随...     

股后侧岛状皮瓣和肌皮瓣的临床应用

目的 探讨应用股后侧岛状皮瓣修复大转子、骶部等处软组织缺损的临床效果.方法 应用顺行股后侧岛状皮瓣修复大转子软组织缺损4例、骶部2例;逆行股后侧岛状皮瓣修复腘窝部皮肤缺损2例;肌皮瓣修复坐骨结节褥疮4例;供区直接缝合.结果 除 1例岛状皮瓣远端发生尖部坏死经植皮愈合外,余病例术后全部成活.随访1～5年,供区愈合良好、受区外形、质地及厚薄均较满意.结论 该皮瓣以臀下动脉股后皮支及股深动脉穿动脉为其血供,解剖恒定,具有血运丰富、血管蒂长和切取容易等优点,适宜修复大转子、骶部坐骨结节及腘窝部等处软组织缺损.     

Skin paddle vascularity of free fibula flap �C A study of 386 cases and a classification based on contribution from axial vessels of the leg

Objective:

The skin paddle of the free fibula flap receives its vascular supply from septocutaneous perforators, musculocutaneous perforators or from both, and these perforators might originate from the peroneal or posterior tibial vessels or from both. The objective of this study was to classify the skin paddles based on the dominance of vascular contribution by these axial vessels through their different perforator systems.

Materials and Methods:

A retrospective analysis of 5-year data of 386 free fibula flaps used in oro-mandibular reconstruction was done and the skin paddle vascularity was studied. While majority of the skin paddles received their blood supply from the peroneal septocutaneous perforators, a few had their dominant supply from the soleus musculocutaneous perforators in addition to peroneal septocutaneous perforators. In few cases, the soleus musculocutaneous perforators were the sole source of blood supply to the skin paddle. The limitation in this study was the inability to augment the clinical observation with cadaveric study.

Results:

The skin paddle of the free fibula flap was classified into four different types (a–d) based on the dominance of vascular contribution by axial vessels of the leg.

Conclusion:

The skin paddle of the free fibula flap has reliable blood supply, but a thorough knowledge of the variations in vascular pattern of the skin paddle is required especially to salvage the larger paddles used in the reconstruction complex oro-mandibular defects.KEY WORDS: Free fibula flap, musculocutaneous perforators, septo cutaneous perforators, skin paddle, vascular supply     

Transaxillary latissimus dorsi flap reconstruction in head and neck cancer. Limitations and refinements in 56 cases

The transaxillary latissimus dorsi musculocutaneous flap is suitable whenever a large volume of tissue is required for head and neck reconstruction. Fifty-six transaxillary latissimus dorsi musculocutaneous flap reconstructions were performed in 55 patients. There were two cases of complete flap necrosis and eight cases of partial flap necrosis. The latissimus dorsi vascular pedicle is separate from the irradiated field. The pedicled latissimus dorsi flap provides coverage of the orbitocranium, including the supraorbital region and central portion of the upper face. In the event that the pedicled latissimus dorsi flap does not reach far enough cephalad, the nutrient vessels may be separated from the axillary artery and anastomosed to vessels in the neck. Combined defects of the esophagus, mandibulofacial region, and neck may be reconstructed with a single large latissimus dorsi flap. Hairless skin particularly suitable for oral cavity reconstruction is usually available. Aesthetic and functional deficits are minimal after latissimus dorsi reconstruction. Disadvantages of this technique include repositioning of the patient, increased blood loss, and longer operating time. Permanent brachial plexus injury may occur. The latissimus dorsi musculocutaneous flap should not be used when defects can be reconstructed by simpler methods.     

Muscle flap monitoring in a rat model with a variable gain quantitative fluorometer.

A variable gain dermofluorometer with a wide range of sensitivities capable of quantifying fluorescein emission from both skin and muscle was tested in a rat latissimus dorsi island muscle flap model. Quantitative fluorometric readings directly from muscle and skin sites that did not undergo surgery were taken at intervals over 2 hours after intravenous fluorescein injection. Muscle flaps with intact pedicles gave an inflow-outflow pattern. A no-outflow pattern was seen in muscle flaps with ligated pedicle veins and a no-inflow pattern was seen in muscle flaps with ligated pedicle arteries. These patterns were similar to the flow pattern seen with quantitative fluorometric monitoring in flaps with cutaneous components. These results suggest that quantitative fluorometry may be applicable to circulation monitoring in muscle flaps.     

Anatomic basis of the gastrocnemius perforator-based flap.

The gastrocnemius muscle is rarely considered today as a musculocutaneous flap. Yet, the posterior calf skin by itself can still be used to advantage as a source of local or perhaps free flaps. Fascial perforators in this region were reexamined in an anatomic study in 10 fresh cadaveric specimens to investigate the possibility of a gastrocnemius muscle perforator-based flap. At least two substantive perforators were found in all limbs, and there was always one overlying the medial gastrocnemius muscle (overall mean, 4.0 +/- 1.8 perforators; range, 2-7 perforators). The origin of these perforators in any given specimen was most commonly as a secondary branch from the medial or lateral sural arteries alone (60%), from the median sural artery as a direct cutaneous branch alone (10%), or from either of the muscle pedicles and/or the median sural artery (30%). Thus, in 90% of limbs, the potential for elevating a gastrocnemius perforator-based flap exists without the need for any muscle sacrifice. Otherwise, a more traditional posterior calf fasciocutaneous flap was possible. Other deeper intramuscular collaterals were also identified so that sequential use of the muscle as a separate flap does not seem to be compromised.