Prefabrication of composite free flaps through staged microvascular transfer: an experimental and clinical study

The feasibility of prefabricating free flaps by inducing, through the process of staged reconstruction, an arteriovenous bundle and its surrounding fascia to perfuse a selected block of tissue was investigated experimentally and clinically. Sixteen rat knee joints were wrapped with their ipsilateral superficial inferior epigastric (SIE) fascia. In 8 joints, the composite flaps were resected en bloc and were immediately replaced orthotopically pedicled upon the superficial inferior epigastric vessels. In the remaining joints, the resection and orthotopic transfer were performed 2 weeks later. Only the joints in the latter group, which benefited from the staging period, were found to be perfused. The long finger proximal interphalangeal joint of a child was reconstructed by the staged microvascular transfer of his second toe proximal interphalangeal joint. At the first stage, a temporalis fascia flap was wrapped around the toe proximal interphalangeal joint and revascularized to the dorsalis pedis vessels. Six weeks later, the joint and its temporalis fascia envelope were dissected, and the "prefabricated" joint flap was transferred to the hand and revascularized to the wrist vessels. Bony union progressed uneventfully with excellent recovery of the range of motion. We conclude that regardless of the indigenous vascular anatomy, an unlimited array of composite free flaps can be constructed and transferred based on induced large vascular pedicles.     

The thigh flap: an osteomyocutaneous free-flap model in the rat

A new experimental model for free-flap transfer has been developed in the rat. This "thigh flap" is an osteomyocutaneous free flap of bone (femur), muscle (thigh), and skin (groin) based on the femoral vessels. The flap is harvested from the left groin and thigh of an inbred female rat and is transferred to a subcutaneous pocket in the left groin of a male rat of the same inbred strain. The femoral vessels supplying the flap are anastomosed end-to-end with the femoral vessels of the recipient. Thirty flaps have been transferred, with 5 technical failures. Three of the remaining 25 flaps developed necrosis within 24 hours. The other 22 flaps remained viable until the rat was sacrificed at 7 days. The survival rate of the thigh flap was thus 88 percent. The model is suitable for use in metabolic, vascular, and immunologic studies of composite free flaps.     

Microautoradiographic studies of phloem loading and transport in the leaf of Zea mays L.

Microautoradiographs showed that [¹⁴C]sucrose taken up in the xylem of small and intermediate (longitudinal) vascular bundles of Zea mays leaf strips was quickly accumulated by vascular parenchyma cells abutting the vessels. The first sieve tubes to exhibit ¹⁴C-labeling during the [¹⁴C]sucrose experiments were thick-walled sieve tubes contiguous to the more heavily labeled vascular parenchyma cells. (These two cell types typically have numerous plasmodesmatal connections.) With increasing [¹⁴C]sucrose feeding periods, greater proportions of thick- and thin-walled sieve tubes became labeled, but few of the labeled thin-walled sieve tubes were associated with labeled companion cells. (Only the thin-walled sieve tubes are associated with companion cells.) When portions of leaf strips were exposed to ¹⁴CO₂ for 5 min, the vascular parenchyma cells-regardless of their location in relation to the vessels or sieve tubes-were the most consistently labeled cells of small and intermediate bundles, and label (¹⁴C-photosynthate) appeared in a greater proportion of thin-walled sieve tubes than thick-walled sieve tubes. After a 5-min chase with ¹²CO₂, the thin-walled sieve tubes were more heavily labeled than any other cell type of the leaf. After a 10-min chase with ¹²CO₂, the thin-walled sieve tubes were even more heavily labeled. The companion cells generally were less heavily labeled than their associated thin-walled sieve tubes. Although all of the thick-walled sieve tubes were labeled in portions of leaf strips fed ¹⁴CO₂ for 5 min and given a 10-min ¹²CO₂ chase, only five of 72 vascular bundles below the ¹⁴CO₂-exposed portions contained labeled thick-walled sieve tubes. Moreover, the few labeled thick-walledsieve tubes of the transport region always abutted ¹⁴C-labeled vascular parenchyma cells. The results of this study indicate that (1) the vascular parenchyma cells are able to retrieve at least sucrose from the vessels and transfer it to the thick-walled sieve tubes, (2) the thick-walled sieve tubes are not involved in long-distance transport, and (3) the thin-walled sieve tubes are capable themselves of accumulating sucrose and photosynthates from the apoplast, without the companion cells serving as intermediary cells.     

Strategic considerations on the configuration of free flaps and their vascular pedicles combined with Ilizarov distraction in the lower extremity

For the injury of the lower leg associated with both bone and soft-tissue defect, the combined free flap and the Ilizarov distraction method were described as a useful treatment modality. During the procedure of distraction, however, revisions were frequently needed to change the pin position or to change the flap configuration. In case of flap ischemia, distraction should be delayed or abandoned. Then, a vascularized bone transfer might be necessary. To avoid these complications and achieve safe distraction, the configuration of the flap with its vascular pedicle should be carefully planned in terms of the future bony lengthening procedures and the concomitant soft-tissue changes of the lower leg. According to the response of local tissue to the distraction process, the lower limb can be divided into four compartments (active mobile, passive mobile, receptive, and restrictive). The configuration of the transferred free flap with its vascular pedicle can be classified into five types. To minimize the undue forces to the vascular pedicle and reduce the possibility of vascular compromise, the transferred free flap should have the configuration that its vascular pedicle lies in the territory of the mobile compartment. In performing free-tissue transfer combined with the Ilizarov method in the lower extremity, the configuration of the flap with its vascular pedicle should be carefully planned, and the characteristics of lower leg tissue should be kept in mind during the distraction.     

Deltopectoral skin flap as a free skin flap revisited: further refinement in flap design, fabrication, and clinical usage

The deltopectoral skin flap is an axial flap; therefore, it can be fashioned as a free skin flap. Although color and texture of the skin are well suited for facial resurfacing, the structural features of inconsistent thickness of the skin, a short vascular pedicle, a minute caliber of the nutrient vessel, and donor site morbidity often preclude the use of this flap for this purpose. The deltopectoral skin flap fabricated as a free skin flap transferred by means of a microsurgical technique was used in 27 patients between 1985 and 1998 at our hospital. The anterior perforating branches of the internal mammary vessels were the primary nutrient vessels of the flap in seven instances. The external caliber of this artery varied between 0.6 mm and 1.2 mm, with an average size of 0.9 mm. The size of the accompanying vein varied between 1.5 mm and 3.2 mm, with an average of 2.3 mm. Coaptation of these vessels with those in the recipient site was technically difficult. Thrombosis occurred at the anastomotic site in three patients, requiring reoperation. Two flaps were saved. The flap failure was drastically reduced in the remaining 20 patients by including a segment of the internal mammary vessel when fabricating the vascular pedicle. The size of the internal mammary arterial segment averaged 2.1 mm, and the average size of the accompanying vein was 2.9 mm. The problem of a bulky flap was managed by surgical defatting/thinning of the flap at the time of flap fabrication and transfer. A V-to-Y skin flap advancement technique of wound closure was used in eight individuals. The flap donor-site morbidities were minimized with this method of wound closure.     

Usefulness of a first transferred free flap vascular pedicle for secondary microvascular reconstruction in the head and neck

The authors found that a previously transferred free flap vascular pedicle, distal to the first microvascular anastomosis, can be used as a recipient vessel for an additional free flap transfer. Free flap transfers were performed by using the standard procedure in patients with head and neck cancer. The mean age of the patients was 62 years. Five patients were men and three were women. A second free flap was transferred for secondary primary head and neck cancer in two cases, facial deformity in two cases, osteomyelitis of the skull in two cases, recurrent cancer in one case, and exposure of a mandibular reconstruction plate in one case. The interval between the two operations was from 4 months to 12 years (median, 21 months). All secondary free flaps were performed successfully. In two cases, the external jugular vein proximal to the previously anastomosed site was used for venous drainage. In another case, additional venous anastomosis was performed for flap congestion. It became clear that a previously transferred free flap vascular pedicle could be used as a recipient vessel for microvascular anastomosis. This is an excellent procedure for additional free flap transfers.     

Notch receptor expression in human brain arteriovenous malformations

The roles of the Notch pathway proteins in normal adult vascular physiology and the pathogenesis of brain arteriovenous malformations are not well‐understood. Notch 1 and 4 have been detected in human and mutant mice vascular malformations respectively. Although mutations in the human Notch 3 gene caused a genetic form of vascular stroke and dementia, its role in arteriovenous malformations development has been unknown. In this study, we performed immunohistochemistry screening on tissue microarrays containing eight surgically resected human brain arteriovenous malformations and 10 control surgical epilepsy samples. The tissue microarrays were evaluated for Notch 1–4 expression. We have found that compared to normal brain vascular tissue Notch‐3 was dramatically increased in brain arteriovenous malformations. Similarly, Notch 4 labelling was also increased in vascular malformations and was confirmed by western blot analysis. Notch 2 was not detectable in any of the human vessels analysed. Using both immunohistochemistry on microarrays and western blot analysis, we have found that Notch‐1 expression was detectable in control vessels, and discovered a significant decrease of Notch 1 expression in vascular malformations. We have demonstrated that Notch 3 and 4, and not Notch 1, were highly increased in human arteriovenous malformations. Our findings suggested that Notch 4, and more importantly, Notch 3, may play a role in the development and pathobiology of human arteriovenous malformations.     

Tissue engineering skin flaps: which vascular carrier, arteriovenous shunt loop or arteriovenous bundle, has more potential for angiogenesis and tissue generation?

This study was designed to clarify which vascular carrier, the arteriovenous shunt loop or the arteriovenous bundle, has more potential as a vascular carrier for an artificial skin flap in rats. An arteriovenous shunt loop was constructed between the femoral artery and vein using an interpositional artery (group I) or vein (group II) graft. For arteriovenous bundle groups, the femoral artery and vein were used and subdivided into two groups: distal ligation type (group III) and flow-through type (group IV). The vascular pedicle was wrapped with an artificial dermis and implanted beneath the inguinal skin for 4 weeks. For the control group, a folded sheet of artificial dermis without any vascular carrier was embedded. In experiment 1, the volumes of generated tissue within the artificial dermis were measured in the experimental and control groups (n = 5 in each group). In experiment 2, the origin of new blood vessels sprouting from the arteriovenous shunt loop and arteriovenous bundle were evaluated histologically. The volume of generated tissue in the shunt groups was significantly greater than that in the bundle groups (p < 0.01). However, the bundle groups also showed a great potential for producing new tissue. Serial histological studies showed that new capillaries were derived not only from the vasa vasorum of the femoral vessels but directly from the femoral vein in both the shunt and the bundle groups. This "sprouting" was extensively exhibited in the group III. Although the arteriovenous shunt loop showed a greater potential for producing new tissue and capillaries, the distal ligation type of bundle was thought to be an effective and practical vascular carrier for producing a tissue-engineered skin flap.     

Leaf structure in relation to solute transport and phloem loading in Zea mays L.

Small and intermediate (longitudinal) vascular bundles of the Zea mays leaf are surrounded by chlorenchymatous bundle sheaths and consist of one or two vessels, variable numbers of vascular parenchyma cells, and two or more sieve tubes some of which are associated with companion cells. Sieve tubes not associated with companion cells have relatively thick walls and commonly are in direct contact with the vessels. The thick-walled sieve tubes have abundant cytoplasmic connections with contiguous vascular parenchyma cells; in contrast, connections between vascular parenchyma cells and thin-walled sieve tubes are rare. Connections are abundant, however, between the thin-walled sieve tubes and their companion cells; the latter have few connections with the vascular parenchyma cells. Plasmolytic studies on leaves of plants taken directly from lighted growth chambers gave osmotic potential values of about-18 bars for the companion cells and thin-walled sieve tubes (the companion cell-sieve tube complexes) and about-11 bars for the vascular parenchyma cells. Judging from the distribution of connections between various cell types of the vascular bundles and from the osmotic potential values of those cell types, it appears that sugar is actively accumulated from the apoplast by the companion cell-sieve tube complex, probably across the plasmalemma of the companion cell. The thick-walled sieve tubes, with their close spatial association with the vessels and possession of plasmalemma tubules, may play a role in retrieval of solutes entering the leaf apoplast in the transpiration stream. The transverse veins have chlorenchymatous bundle sheaths and commonly contain a single vessel and sieve tube. Parenchymatic elements may or may not be present. Like the thick-walled sieve tubes of the longitudinal bundles, the sieve tubes of the transverse veins have plasmalemma tubules, indicating that they too may play a role in retrieval of solutes entering the leaf apoplast in the transpiration stream.     

Venous malformations of skeletal muscle

Intramuscular venous malformations are often mistaken for tumors because of a similar presentation and improper nomenclature. This is a review of 176 patients with venous malformations localized to skeletal muscle compiled from the Vascular Anomalies Center at Children's Hospital from 1980 through 1999. The female-to-male ratio was 2:1. Two-thirds of skeletal muscle venous malformations were noted at birth; the remainder manifested in childhood and adolescence. Venous malformations occurred in every muscle group, most often in the head and neck and extremities. Pain and swelling were the usual presenting complaints. Skeletal problems, such as fracture, deformation, or growth abnormalities, were rare. Hormonal exacerbation and intralesional bleeding were infrequent. Magnetic resonance imaging showed the lesions to be isointense to surrounding muscle on T1-weighted sequences and hyperintense on T2-weighted images. Characteristic tubular or serpentine components were oriented along the muscular long axis. Thrombi were hyperintense on T1-weighted and hypointense on T2-weighted sequences; phleboliths were seen as signal voids on all sequences. Gross examination of resected specimens revealed multicolored tissue with dilated vascular channels, frequently containing phleboliths. Light microscopy showed aggregates of primarily medium-sized, thin-walled vascular channels with flat endothelium and variable smooth muscle, most closely resembling dysplastic veins. Three lesions had a different histologic appearance consisting predominantly of small vessels with capillary structure and proliferative activity admixed with large feeding and draining vessels, similar to a lesion called intramuscular capillary hemangioma in the literature. The endothelium in these three lesions was negative for glucose transporter-1 by immunostaining. Eight percent of the patients, who had minor or no symptoms, were not treated. Twenty-four percent of the patients were managed conservatively (with aspirin and compressive garments); for 17 of these patients (10 percent of 176), noninvasive therapy was not successful, and they proceeded to sclerotherapy, excision, or both. A total of 31 percent of the patients had sclerotherapy, 20 percent had excision, and 27 percent had combined sclerotherapy and excision. Sclerotherapy was used for diffuse lesions, except for those with multiple intralesional thromboses, neurologic impairment, or compressive signs and symptoms. Resection was preferred for venous malformations well localized to a single muscle or muscle group, particularly if the muscles are expendable. Therapeutic outcomes were recorded in the charts or obtained by telephone interview in 122 of the patients (69 percent). Of these, compression garment and aspirin, resection, sclerotherapy, or combined excision and sclerotherapy improved symptoms in 121 patients (92 percent); no change was noted in 10 patients (8 percent). Only one patient was worse (self-reported) after intervention.     

Formation of independently revascularized bowel segments using the rectus abdominis muscle flap: a rat model for jejunal prefabrication

Reconstruction of the pharyngoesophagus with free jejunal transfer is a major challenge when recipient neck vessels are absent because of previous surgery or irradiation. In such instances, jejunal transfer using a muscle flap as a "vascular carrier" may be a problem-solving alternative. Pretransfer vascularization of the jejunum is achieved by wrapping the muscle flap around the small bowel segment. After a short staging period, the mesenteric pedicle is divided and the bowel segment is transferred up to the neck based on its new blood supply. The objectives of this study were to develop an animal model for prefabricating independently revascularized jejunal segments using the rectus abdominis muscle flap and to determine the minimal time required for independent bowel survival. Twenty-four mature (500-g to 700-g) rats were divided into six experimental groups of four animals each. In each animal, a 1.5-cm segment of proximal jejunum was isolated on two jejunal arteries and wrapped with a superior pedicled rectus abdominis muscle flap. To determine the time of neovascular takeover, the mesenteric pedicles were ligated on postoperative day 2 (group I), day 3 (group II), day 4 (group III), day 5 (group IV), day 6 (group V), and day 7 (group VI). At the time of pedicle ligation, the composite flap was transposed to a new subcutaneous position. Viability of bowel was assessed according to gross appearance and histologic examination 48 hours after transfer. Complete survival of revascularized jejunum in 11 of 12 animals was obtained after pedicle ligation on postoperative day 5 and beyond (p < 0.0001, Fisher's exact test). These bowel segments demonstrated luminal patency, intact pink mucosa, mucus production, and visible peristalsis. Histologic examination showed healthy intestinal epithelium and tissue integration along the serosa-muscle interphase. In contrast, pedicle ligation on day 4 and earlier resulted in varying degrees of bowel necrosis characterized by flattening or ulceration of mucosa (day 4), mucosal sloughing and necrosis of mural musculature (day 3), and complete loss of bowel architecture with lumen obliteration (day 2). These findings suggest that jejunal segments may be independently revascularized with the rectus abdominis muscle flap in the rat model. Complete survival and gross normal bowel function may be obtained without mesenteric perfusion after a minimal time of 5 days.     

数字化血管三维模型对烧伤患者面部修复术术后皮瓣存活的影响

目的:探讨数字化血管三维模型对烧伤患者面部修复术术后皮瓣存活的影响。方法:选择2012年4月至2017年4月在我院接受组织瓣转移面部修复术的烧伤患者146例,分为对照组(n=64)和研究组(n=82)。对照组术前采用超声多普勒探测患者供区皮瓣的血管位置,走向并标记探测结果,根据多普勒探测结果结合术前设计行皮瓣转移术。观察组术前3~5 d采用CTA技术检查患者供区皮瓣面部受区血管位置、血管走向等,将检查结果通过计算机进行血管三维重建,根据皮瓣血管与受区血管重建模型修订手术方案后行皮瓣转移术。观察和比较手术时间、术后感染发生率、皮瓣断蒂时间、皮瓣血运障碍发生率和术后皮瓣坏死率。结果:研究组手术时间显著短于对照组(P0.01),两组术后感染发生率分别为7.81%和1.21%,研究组明显低于对照组(P0.01)。研究组的皮瓣断蒂时间为17.1±2.5 d,明显短于对照组(21.3±2.8 d,P0.01);对照组皮瓣血运障碍发生率为17.19%,研究组并未发现血运障碍病例。对照组术后皮瓣坏死率为7.81%,而研究组未出现皮瓣坏死病例,存活率为100%,明显高于对照组(P0.05)。结论:术前数字化血管三维模型的建立用于烧伤患者面部修复术可缩短手术时间,提高手术效率,降低术后皮瓣供血障碍的发生率及皮瓣死亡率,有利于患者术后恢复。     

Light microscopic study of blood vessels of the nasal cavity of the pig

4 adult pigs were used for light microscopic studies to depict the relationship between nasal blood vessels and the surface epithelium, and to describe the histomorphology of these vessels. After giving an electric shock, animals were bled to death. Tissues were collected from three regions in the nasal cavity after splitting heads sagitally. Different types of vessels were described and a new classification was suggested. Arteries were muscular in type with, as well as without, internal elastic laminae. Thick-walled veins (characterized by smooth muscle cells in the tunica media) were present throughout the nasal cavity, while thin-walled veins or cavernous spaces were discernible only in the caudal one third of the nasal cavity. Further, arteriovenous anastomoses, epithelioid arterioles, and free smooth muscle cells in the propria submucosa were observed throughout the nasal cavity.     

The trauma of suction-assisted lipectomy cannula on flap circulation in rats.

The effect of suction-assisted lipectomy on cutaneous blood vessels of inguinal skin flaps was studied and compared in 191 rats. Different types of cannula tips were used; the number of passes was standardized. In one experiment, following suctioning, 3 X 2 cm groin island flaps based on inferior epigastric pedicles were raised and then reattached. Fluorescein dye study and microangiography were performed to evaluate flap viability. Flap survival was determined clinically and by histologic examination on the fifth postoperative day. Three-sided inguinal random-pattern flaps were raised in a second experiment and reattached following suctioning. On the fifth postoperative day, surviving flap areas were measured using standard photographs and an imaging computer and were compared with controls. Results showed that cannula passes accompanied by vacuum are harmful to vessels, while those unaccompanied by vacuum are not. The greater the number of suctioning passes, the more trauma there is to vessels and the greater is the likelihood of flap necrosis. Conical and spatula tips were more harmful to vessels than spherical, cobra, keel cobra, or Fournier tips. These results support the conclusion that suction-assisted lipectomy enhances the possibility of skin necrosis by traumatizing the vascular pedicle of a flap, especially when it is used as an adjunct to flap elevation.     

An outcome analysis comparing the thoracodorsal and internal mammary vessels as recipient sites for microvascular breast reconstruction: a prospective study of 100 patients

The thoracodorsal vessels have been the standard recipient vessels for the majority of surgeons performing free transverse rectus abdominis musculocutaneous (TRAM) flap reconstructions. Recently, the internal mammary vessels have been recommended as the first-choice recipient vessels for microvascular breast reconstruction. This approach requires a shorter pedicle length, allows for central placement of flap tissue, and avoids axillary scarring. The use of the internal mammary vessels may provide for a shorter operative time and a higher-quality aesthetic reconstruction. The authors performed a prospective trial examining the differences in operative and aesthetic outcomes between each recipient site. A prospective trial of 108 consecutive free-tissue transfers was conducted in 100 patients. The first 60 TRAM flap patients were randomized so that 30 flaps were anastomosed to the internal mammary vessels and 30 were anastomosed to the thoracodorsal vessels, whereas the recipient vessels for the remaining 40 patients were left to the discretion of the surgeon. Of the 40 nonrandomized patients, 10 patients underwent reconstruction using the internal mammary vessels and 30 patients underwent reconstruction using the thoracodorsal vessels. The patients' medical history and hospital course were noted. To evaluate aesthetic outcome, a group of five blinded nonmedical observers and three blinded plastic surgeons graded the reconstructions in the 60 TRAM flap patients for symmetry and overall aesthetic result on a scale of 1 to 5. Blinded practitioners administered postoperative questionnaires to patients regarding recovery time and satisfaction with the aesthetic result. Forty-three flaps were transferred to the internal mammary vessels and 65 were transferred to the thoracodorsal vessels. No significant differences existed between groups with regard to age of preoperative risk factors. Average operative time was 6 hours in each group. Average hospital stay was 5.8 days in each group. Conversion from initial recipient vessel to a secondary recipient site occurred in 12.5 percent of internal mammary reconstructions and 7 percent of thoracodorsal reconstructions. All converted internal mammary cases occurred in left-sided reconstructions and were attributable to problems with the veins. Overall, 20 percent of left-sided internal mammary reconstructions were found to have an inadequate recipient vein. Unusable thoracodorsal vessels were found only in delayed reconstructions, at a rate of 15 percent in the delayed setting. All flaps from converted procedures survived without complications. Average follow-up was 20 months, during which time there was one flap loss in the thoracodorsal group. There were no significant differences in complication rates between groups. Average aesthetic grade was 3.6 in each group. Postoperative recovery time and overall patient satisfaction were not significantly different between groups. Either recipient site can provide for a safe and acceptable result; however, surgeons should be aware of conversion rates and plan appropriately if recipient vessels appear unusable for free-tissue transfer.     

Factors affecting outcome in free-tissue transfer in the elderly

Free-tissue transfers have become the preferred surgical technique to treat complex reconstructive defects. Because these procedures typically require longer operative times and recovery periods, the applicability of free-flap reconstruction in the elderly continues to require ongoing review. The authors performed a retrospective analysis of 100 patients aged 65 years and older who underwent free-tissue transfers to determine preoperative and intraoperative predictors of surgical complications, medical complications, and reconstructive failures. The parameters studied included patient demographics, past medical history, American Society of Anesthesiology (ASA) status, site and cause of the defect, the free tissue transferred, operative time, and postoperative complications, including free-flap success or failure. The mean age of the patients was 72 years. A total of 46 patients underwent free-tissue transfer after head and neck ablation, 27 underwent lower extremity reconstruction in the setting of peripheral vascular disease, 10 had lower extremity traumatic wounds, nine had breast reconstructions, four had infected wounds, two had chronic wounds, and two underwent transfer for lower extremity tumor ablation. Two patients had an ASA status of 1, 49 patients had a status of 2, 45 patients had a status of 3, and four had a status of 4. A total of 104 flaps were transferred in these 100 patients. There were 49 radial forearm flaps, 34 rectus abdominis flaps, seven latissimus dorsi flaps, seven fibular osteocutaneous flaps, three omental flaps, three jejunal flaps, and one lateral arm flap. Four patients had planned double free flaps for their reconstruction. Mean operative time was 7.8 hours (range, 3.5 to 16.5 hours). The overall flap success rate was 97 percent, and the overall reconstructive success rate was 92 percent. There were six additional reconstructive failures related to flap loss, all of which occurred more than 1 month after surgery. Patients with a higher ASA designation experienced more medical complications (p = 0.03) but not surgical complications. Increased operative time resulted in more surgical complications (p = 0.019). All eight cases of reconstructive failure occurred in patients undergoing limb salvage surgery in the setting of peripheral vascular disease. Free-tissue transfer in the elderly population demonstrates similar success rates to those of the general population. Age alone should not be considered a contraindication or an independent risk factor for free-tissue transfer. ASA status and length of operative time are significant predictors of postoperative medical and surgical morbidity. The higher rate of reconstructive failure in the elderly peripheral vascular disease population compares favorably with other treatment modalities for this disease process.     

Prefabrication of jejunum for challenging reconstruction of cervical esophagus

A significant benefit exists for a jejunal replacement of the cervical esophagus, if indicated. The absence of available recipient vessels may impede free tissue transfer. If vascular induction between a vascular carrier and the selected jejunal segment is done as a kind of flap prefabrication, the jejunal interposition flap can be used without the need for complex microsurgery.     

Superiority of the deep circumflex iliac vessels as the supply for free groin flaps. Clinical work.

In this paper we present 16 cases of free transfer of compound flaps from the groin, 11 using the deep circumflex iliac vessels as a stem and 5 using the superficial circumflex iliac vessels as a stem. We found the deep vessels superior in many ways to the superficial vessels for this purpose; they are larger, permitting greater ease in anastomoses and providing more reliable blood flow. We believe that larger osteocutaneous or myocutaneous flaps can be transferred on the deep vessels than on the superficial ones-and that the deep circumflex iliac flap may supplant the conventional free going flap in most situations. The method evolved in response to patient need, not for surgical éclat.     

Posterior interosseous free flap with extended pedicle for hand reconstruction

The anatomy of the posterior interosseous vessels makes them suitable as a donor area of free flap. The skin island can be designed on the perforating vessels of the distal third of the forearm, up to the dorsal wrist crease, to increase the pedicle length (7 to 9 cm). A series of nine flaps transferred to reconstruct hand defects is presented. All flaps were designed over the dorsal distal forearm, and dimensions permitted direct closure of the donor site (up to 4 to 5 cm wide). Apart from a linear scar, donor morbidity was negligible. All transfers were successful. Although its dissection is somewhat tedious, the anatomy of the vascular pedicle is suitable for microanastomosis and the skin island is thin, although hairy. The posterior interosseous free flap with extended pedicle may be a good choice when limited amounts of thin skin and a long vascular pedicle are needed.     

Aphid (Sitobion yakini) investigation suggests thin-walled sieve tubes in barley (Hordeum vulgare) to be more functional than thick-walled sieve tubes

Barley, like most other grasses that have been studied, contains two kinds of sieve tube. The first formed are called thin-walled sieve tubes because of their thin wall compared to the late-formed, and are associated with companion cells. The late-formed are thick-walled sieve tubes, which differentiate next to the metaxylem vessels and lack companion cells. Aphid ( Sitobion yakini (Eastop) feeding was studied using light microscopy to determine if they preferentially feed from thin- or thick-walled sieve tubes in the barley leaf. Penetration of the stylets through the leaf epidermis and mesophyll was largely intercellular, becoming partly intercellular and, partly, intracellular inside the vascular bundle. Sixteen of 19 pairs of stylets (84%), and 293 of 317 (92%) stylet tracks terminated at the thin-walled sieve tubes, suggesting that Sitobion yakini feeds preferentially on the thin-walled sieve tubes which seem to be more attractive to the aphid. These thin-walled sieve tubes are thus probably the most functional in terms of phloem loading and transport.