Prefabricated and prelaminated flaps for head and neck reconstruction

Flap prefabrication and prelamination are evolving, new techniques that are useful in reconstructing complex defects of the head and neck. Flap prefabrication involves the introduction of a new blood supply by means of a vascular pedicle transfer into a volume of tissue. After a period of neovascularization, this volume of tissue may be transferred, based only on its implanted vascular pedicle. The transfer may be local transposition or by microsurgical transfer. Flap prelamination refers to a technique in which additional tissue is added to an existing flap (without manipulation of its axial blood supply) to make a multilayered flap that may be used for complex, three-dimensional multilayered reconstructions. This technique may be used locally or at a distance, requiring microvascular transfer. Examples of each are described in this article.     

Experimental study on secondary living bone graft--method of creating new donor by vascular bundle implantation to isolated bone

The purpose of this study was to demonstrate the possibility of creating a new donor for a vascularized bone graft by a vascular bundle implantation to an isolated bone. Preliminary experiments on rats were performed preliminarily in order to investigate the revascularization of bone by a vascular bundle implantation and/or by implanting in muscular tissues (experiment-1). When a vascular bundle was implanted to the intramedullary cavity of an isolated bone and then the bone was implanted in muscular tissues, the isolated bone was more readily revascularized and revitalized than under other conditions. In experiment-2, the revascularized bone was transferred to the abdominal subcutaneous space on the vascular pedicle that was an implanted vascular bundle. Histologic and fluorochrome bone labeling studies showed that the revascularized bone was kept revitalized after the transfer. These results demonstrate that muscle and vascular bundle co-operated effectively in the revascularization of bone. Vascular bundle can also act as a pedicle for transferring the revascularized bone.     

Historical review of bone prefabrication

Prefabricated tissue represents a bridge between traditional reconstructive surgery and tissue engineering. Initially used in the 1960s in reconstructive plastic surgery, in the 1980s it was also used in orthopedics. The term “prefabricated” indicates a process of neovascularization of a tissue by implanting a vascular pedicle inside the tissue itself; this tissue can be then reimplanted either at a short distance through the pedicle itself, or as a free graft by microvascular anastomosis. The purpose of prefabrication is to build a tissue (muscle, bone, skin, or composite) with characteristics as similar as possible to those of the defect to fill, thus minimizing morbidity in the donor site and improving the reconstructive effectiveness. We present a review of the literature that includes the main experiments performed until now in which a bone segment has been reconstructed using scaffolds and growth factors in relationship to the local blood supply or to the use of a vascular pedicle.     

Severe trismus secondary to periosteal osteogenesis after fibula free flap maxillary reconstruction

BACKGROUND: Fibula free tissue transfer is routinely used for reconstruction of bony defects in the head and neck. During flap preparation, well-vascularized periosteum is left adjacent to the proximal vascular pedicle. It is known that periosteum can have significant osteogenic potential in the proper settings. Complications related to periosteal osteogenesis of a fibula free flap pedicle have not been previously reported. CASE HISTORY: A 12-year-old girl with a history of squamous cell carcinoma of the maxilla underwent delayed fibula free flap reconstruction of a maxillary defect. The patient had severe trismus develop postoperatively and was found to have osteogenesis along the vascular pedicle. This bone formed a solid bridge from the maxilla to the mandible. Two resections were required, which included excision of the vascular pedicle, to eliminate further osteogenesis and resolve the patient's trismus. CONCLUSIONS: The potential for periosteal osteogenesis does exist with fibula free tissue transfer and can have significant consequences. Potential promoters of osteogenesis should be identified and if possible altered in certain clinical scenarios to prevent complications from new bone growth.     

Reverse radial forearm flap as a source of soft tissue and blood supply for thumb reconstruction

Soft-tissue deficiency is sometimes a major problem in thumb reconstructive cases with toe-to-thumb transfer. In the patient presented, a reverse radial forearm flap was used to provide a vascular pedicle for anastomosis with the second toe vessels. The flap also provided soft-tissue coverage for the metatarsal bone of the transferred toe. The radial artery and concomitant vein were used for the dorsalis pedis artery and vein anastomosis. The skin island of the forearm flap was wrapped around the transferred metatarsal bone. Using this technique, two limiting problems in toe-to-hand transfers were solved at the same time. In the crushed hand, sometimes it is not possible to find enough soft tissue and a good vascular pedicle for a new thumb, and this option seems to be a reasonable choice.     

Evolution of an in vivo bioreactor.

The ideal bone graft substitute requires osteoconductive, osteoinductive, and osteogenic components. This study introduces an "in vivo bioreactor," a model in which pluripotent cells are recruited from circulating blood to a vascularized coralline scaffold supplemented with bone morphogenetic protein-2 (BMP-2). The bioreactor generates new, ectopic host bone with the capability of vascularized tissue transfer. More importantly, bone is reproducibly formed in a closed and malleable environment. In a rat model, the superficial inferior epigastric vessels were isolated, ligated, and then threaded through a prefabricated coral cylinder (hydroxyapatite, ProOsteon 500). Experimental groups were characterized by the following variables: (1) with/without incorporation of vascular pedicle; (2) with/without addition of BMP-2 (0.02 mg/cm3). Scaffolds were harvested 6 weeks after implantation, embedded and sectioned. Tissue samples were decalcified, fixed, and stained with H&E, trichrome green, and CD31/PECAM-1 (a marker of endothelial cells). Vascularized coral scaffolds supplemented with BMP-2 presumably recruited circulating mesenchymal stem cells to generate bone. Bone formation was quantified through histological analysis, and reported as a percentage, area bone/area cross section scaffold x 100. Mean bone formation was 11.30%+/-1.19. All scaffolds supplied by the vascular pedicle, regardless of BMP-2 supplementation, demonstrated neo-vascular ingrowth. Scaffolds lacking a pedicle showed no evidence of vascular ingrowth or bone formation. This paper introduces a model of a novel "in vivo bioreactor" that has future clinical and research applications. The tissue engineering applications of the "bioreactor" include treatment of skeletal defects (nonunion, tumor post-resection reconstruction). The bioreactor also may serve as a unique model in which to study primary and metastatic cancers of bone.     

Rabbit Tibial Periosteum and Saphenous Arteriovenous Vascular Bundle as an In Vivo Bioreactor to Construct Vascularized Tissue‐Engineered Bone: A Feasibility Study

The aim of this project was to construct vascularized tissue‐engineered living bone with an autologous vascular network by means of a rabbit bioreactor in vivo. The key components of the in vivo bioreactor for bone formation were the vascularized tibial periosteum and the saphenous vascular bundle. Beta‐tricalcium phosphate (β‐TCP) scaffolds were implanted into the in vivo bioreactor (vascular pedicle implantation and vascularized periosteum encapsulation). At 4 weeks postsurgery, new bone formation was mainly “cartilage‐bone inducing” in the inner periosteum, and was primarily seen in the outer aspects of the scaffold with some amount in the middle part as well. Microvascular infusion showed that direct revascularization of β‐TCP was obtained by means of vascular implantation. Triple staining results showed a large amount of blue collagen fibers. Vascular endothelial growth factor immunohistochemical staining displayed endothelial cells of new blood vessels in bone tissue. The bioreactor established in this study can be used to prepare tissue‐engineered bone with a vascular network.     

A new flap model in rats: iliac osteomusculocutaneous flap

Although osteomusculocutaneous flaps are used frequently in clinical practice to repair defects involving soft tissue and bone, there are still many questions that remain to be answered regarding their basic physiology. To accomplish such basic science studies, simple and reliable animal osteomusculocutaneous flap models are needed. The purpose of this study was to describe a new flap model in rats--namely, the iliac osteomusculocutaneous flap. Thirty adult Wistar rats weighing 200 to 250 g were used in this experiment. In 15 rats, the vascular anatomy of the iliolumbar vessels and their relation with adjacent soft tissues and the iliac bone was determined by anatomic dissection. Based on this anatomic study, the iliac osteomusculocutaneous flap model was created in rats. The flap is comprised of a skin island (3 x 3 cm) in the flank region, a 1 x 1-cm segment of iliac bone, and an abdominal wall muscle cuff. In 10 rats, the flap was raised as an island flap based on its vascular pedicle of iliolumbar vessels, and was replaced in situ. In the remaining 5 rats, the flap was transferred to the groin region as a free flap. Direct observation on postoperative day 7 revealed that the skin island of all the flaps was completely viable. Bone scintigraphy performed on postoperative day 3 in free flaps demonstrated radionuclide uptake, indicating viability of the bony segment. The dye injection study revealed ink staining within blood vessels of the bone, confirming its viability. Microangiography of the flap demonstrated vascularity of each component of the flap by the iliolumbar vessels, including a distinct branch to the iliac bone. The authors conclude that the iliac osteomusculocutaneous flap of the rat is a simple and reliable flap model that offers the following advantages: (1) It is a true osteomusculocutaneous flap, (2) it can be used as a free flap without the need for an isogeneic rat, (3) the vascular pedicle is consistent, and (4) it is harvested from a small-animal species.     

髂腰真皮下血管网轴型皮瓣在手部创面修复中的应用

目的:研究一种用于上肢远端皮肤软组织缺损的理想修复方法。方法:选择27例上肢远端(前臂及手部)皮肤软组织缺损创面进行修复研究。在同侧髂腰部设计所需大小和形状的髂腰轴型皮瓣,将该皮瓣进行精细减薄制成真皮下血管网轴型皮瓣,皮瓣中的旋髂浅动脉完好保留,带蒂转移修复上肢远端创面,3周后断蒂完成修复。结果:本组27个髂腰真皮下血管网轴型皮瓣移植后全部成活。12个月后随访18例,皮瓣组织无肿胀,表面美学效果满意,皮瓣感觉恢复较好。结论:髂腰轴型真皮下血管网带蒂皮瓣移植是修复上肢远端皮肤软组织缺损的理想方法。     

The healing of canine vascularized segmental tibial osteotomies. The effect of retained endosteal circulation

Forty-eight pairs of canine tibial segmental osteotomies, 4 cm in length, were investigated to determine the progress of regeneration. The tibial segment was stripped of all soft tissue in one limb and the vascular pedicle was preserved in the contralateral limb. This allowed the healing of the tibial segments, vascular versus nonvascular, to be compared using sequential blood flow and roentgenographic and angiographic data. The blood flow to the vascular bone segment quadrupled at three weeks and then gradually decreased to 1.5 times baseline at one year. The nonvascular tibial segment showed a linear increase in flow for three months, achieving a level comparable to the contralateral vascular tibia segment. Peak flow in the vascular tibia at three weeks was four times that of the nonvascular tibia. Blood-vessel ingrowth from each osteotomy site progressed at a linear rate but was three times faster in the vascular bone. The deposition of callus and the rate of osteotomy healing were accelerated significantly in the vascular group. At three months 87% of the vascular tibial osteotomies healed versus 43% of the nonvascular osteotomies; these results represent significant advantages in the rate of healing in vascular versus nonvascular segmental tibial osteotomies. Segmental vascular bone grafts that are internally fixed with plate and screws can preserve the vascular structure and its advantages in bone regeneration.     

Clinical significance of the secondary pedicle amputation of the repair of distal defects with pedicled axial flap

We aimed to explore the clinical significance of the secondary pedicle amputation of the repair of distal defects with pedicled axial flap. Five patients who underwent pedicled axial flap transfer to repair a large area of skin and soft tissue defects in our hospital were included in this retrospective study. Detailed information including general data and clinical data, such as preoperative complication, type of primary wound, the distance between the primary wound and the donor site (cm), postoperative complications, and types of axial flap were collected. The patients had good joint movement at 6 months after pedicle amputation. At 48 hours after transplantation, except for the last patient (NO.5), there were no obvious complications such as blood supply disorder, infection, and incision dehiscence of the patients, and the flaps survived well. Just after pedicle amputation, 3 and 6 months after pedicle amputation, the flaps survived well with good local morphology. Forty‐eight hours after operation, part of the distal flap in the last patient (NO.5) was necrotic. After 6 months of pedicle amputation, part of the flap was transferred to the distal wound again. At 6 months after pedicle amputation, these patients could accept local scars even though the scar of the last patient was obvious. The secondary pedicle amputation of the repair of distal defects with axial flap could avoid the compression of the vascular pedicle in the subcutaneous tunnel between the donor site and the primary wound, which may ensure the bold supply and increase the survival rate of the flap.     

腰椎滑脱后路不同融合术式的有限元研究

目的 建立L4.5，滑脱节段的有限元模型，研究椎弓根螺钉内固定加后外侧植骨融合、椎弓根螺钉内固定加双枚椎间融合器（cage）植入及椎弓根螺钉内固定加单枚融合器植入等3种融合术式的固定节段的稳定性。方法 选择一名56岁退变性腰椎滑脱女性患者，以k节段为研究对象，采用螺旋CT对其进行层厚1．0mm的连续水平扫描，将所得图像进行轮廓提取和阈值分割后，借助Ansys9．0软件，建立L4.5滑脱节段三维非线性有限元模型。同时根据椎弓根螺钉、融合器的几何尺寸，分别建立其相应的有限元模型。在此基础上，根据临床术式将上述模型进行不同组合，分别建立椎弓根螺钉固定加后外侧植骨融合、椎弓根螺钉固定加双枚融合器植入及椎弓根螺钉固定加单枚融合器植入等3种腰椎滑脱后路融合术式的有限元模型，然后分别施加压缩、前屈、后伸、侧屈及旋转等各种生理载荷，观察各模型不同载荷下螺钉、融合器的应力分布及融合节段的角位移变化，由此比较各模型的稳定性。结果 后外侧植骨融合术式的螺钉应力和角位移明显高于椎体间融合术（P〈0．01）；椎弓根螺钉内固定加单枚融合器植入与椎弓根螺钉内固定加双枚融合器植入两组之间螺钉应力、融合器应力及固定椎体的角位移的差异无统计学意义（P〉0．05）；各模型固定节段螺钉及融合器的最大有效应力均出现于前屈时。结论 椎弓根螺钉内固定加单枚或双枚融合器植入的稳定性优于椎弓根螺钉内固定加后外侧植骨融合；对于椎体间融合，植入单枚融合器和双枚融合器的稳定性无明显差别。     

Experimental fascial flap model in the dog: free flap of the dorsal thoracic fascia

For years, various types of fascial flaps have been used in clinical practice; however, there are many unanswered questions regarding their basic physiology, anatomy and histopathologic changes occurring after transfer. Simple and reliable flap models are needed to investigate these questions, but very few of these flap models have been described in experimental animals to date. The purpose of this study was to describe a new reliable fascia flap model in the dog-the dorsal thoracic fascia flap. This fascia is defined as the anatomic layer that contains the blood supply to the scapular and parascapular fasciocutaneous flaps. Fourteen adult dogs were used in this experiment. The vascular anatomy of the dorsal thoracic fascia was studied by anatomic dissection and microangiography. Anatomic dissection revealed that the main axial vessel supplying the dorsal thoracic fascia was the superficial branch of the thoracodorsal vessel. Based on the vascular pedicle, fascia flaps generally measuring 15 x 24 cm were created. At gross observation, all of these large flaps based solely on the vascular pedicle were observed to be well-perfused. Microangiographic examination revealed the intense vascularity of the superficial branches of the thoracodorsal vessels in the whole area of all flaps. It was concluded that this is a simple and reliable fascial flap model which can be prepared as a free or pedicled flap. It has a consistent, long vascular pedicle with large vessel diameters supporting a large fascial flap.     

足趾移植再造拇手指顽固性动脉痉挛的处理体会

目的 介绍足趾移植再造拇、手指术中和术后发生顽固性动脉痉挛的处理方法。方法 对19例拇手指缺损的患者，应用游离第二足趾移植再造拇手指术，其中10例在足趾游离后血管断蒂前发生动脉顽固性痉挛，术中仍按常规处理方法进行血管断蒂，拇、手指再造术。9例发生在第二足趾移植再造拇、手指血管吻合通血后至术后83h出现动脉顽固性痉挛而行手术探查，术中将痉挛段动脉切除，取前臂浅静脉作移植。结果 术后按显微外科常规方法处理，19例再造拇、手指全部获得成活。结论 对拇、手指再造术中和术后出现的顽固性动脉痉挛，采用即时性断蒂或静脉移植桥接动脉的方法是可行、有效的。     

Aerosol transfer of bladder urothelial and smooth muscle cells onto demucosalized colonic segments: a pilot study

PURPOSE: We developed a cell transfer technology for covering demucosalized colonic segments with bladder urothelium. This covering would be achieved through aerosol spraying of single cell suspension of bladder urothelial and smooth muscle cells with fibrin glue onto the demucosalized colonic segments. MATERIALS AND METHODS: In 6 piglets (20 kg.) a 4 cm.2 area of bladder was excised. Single cell suspension of bladder urothelial and smooth muscle cells was prepared. A segment of detubularized sigmoid colon was isolated on its vascular pedicle and demucosalized. The single cell suspensions were combined with an equal volume of fibrin glue and sprayed over the raw submucosal surface of the sigmoid segment. The sigmoid segment was retubularized and sutured to the posterior peritoneum. Animals were sacrificed 4 weeks later, and the segment was submitted to histological and immunohistochemical analysis. RESULTS: Sigmoid segments appeared grossly intact with no reduction in surface area. Hematoxylin and eosin architecture revealed an intact urothelial layer. Deep to this layer was a randomly aligned but distinctly segregated layer of smooth muscle cells. The urological new smooth muscle layer stained positive for calponin and the urothelial layer was cytokeratin-7 and uroplakin III positive. CONCLUSIONS: Separation, cell suspension and aerosol delivery of bladder urothelial and smooth muscle cells in fibrin glue can successfully transfer these urological cell populations to a new host tissue commonly used in urological reconstruction. In vivo co-culture of bladder smooth muscle and urothelial cells results in coverage of a large area of demucosalized gut providing new potential for transfer and reconstitution of urologically functionally appropriate tissue to the bladder itself.     

带血管蒂髂骨瓣复合骨基质明胶移植治疗股骨颈骨折不愈合

目的探讨带血管蒂髂骨瓣复合骨基质明胶移植治疗青壮年股骨颈骨折不愈合的疗效。方法本组28例股骨颈骨折经手术或非手术治疗6～9个月，骨折仍不愈合者，采用带血管蒂髂骨瓣复合骨基质明胶移植，术后观察骨折愈合，股骨头坏死及关节功能恢复情况。结果28例骨折全部愈合，关节功能按Ja-cobs标准评定，优19例，良7例，差2例。结论青壮年股骨颈骨折不愈合的手术治疗，带血管蒂髂骨瓣复合骨基质明胶(BMG)移植是有效术式，治疗结果体现了该术式具有“活骨移植”及诱导成骨的双重作用，疗效明显。     

带皮管蒂前臂皮瓣移植修复颌面部软组织缺损

目的：介绍前臂皮瓣带皮管蒂移植修复颌面部软组织缺损的方法。方法：应用带皮管蒂前辟以瓣移植修复颌面部软组织缺损4例,对其进行临床经验总结,结果：4例皮瓣均成活,软组织缺损修复后外形满意,无感染等并发症。结论：前臂皮瓣带皮管蒂移植解决了受区供给血管限制的问题,拓展了该皮瓣的应用途径,与局部区域条件差,无条件游离使用时,带皮管蒂前臂移植是颌面部软组织缺损修复可供采用的有效方法。     

异体下颌骨移植再血管化的三维结构观察与骨代谢研究

为了观察同种异体骨移植后再血管化的过程，用６只家兔制作下颌骨缺损模型，并用冷冻异体下颌骨移植修复缺损。采用血管铸型法，制备移植骨再血管化模型，立体地观察新生血管与周围组织的关系，并用放射性核素骨显像显示的骨生长代谢作为对照。结果显示：移植骨的新生血管可在骨膜下沿骨吸收通道长入移植骨，骨生长代谢较旺盛。表明，宿主软组织血管直接长入移植骨为再血管化的主要模式之一。     

带血管蒂大转子骨瓣及联合髂骨(膜)瓣治疗股骨头缺血性坏死

目的：为完善带血管蒂的不同骨瓣转移术治疗股骨头缺血性坏死。方法：应用带旋股外侧血管横支的大转子骨瓣，联合升支髂骨瓣和旋髂深血管蒂的髂骨（膜）瓣３种方法。６种术式对股骨头进行了修复和再造，临床应用１９１例２２０侧。结果：１１５例１３０侧经１年６个月至１１年随访取得了良好的效果。结论：带血管蒂的大转子骨瓣联合髂骨（膜）瓣转移的方法适合青壮年股骨头缺血性坏死的各期病变的治疗。