Tissue expander capsule as an induced vascular bed to prefabricate an axial vascularized buccal mucosa-lined flap for tubularized posterior urethral reconstruction: Preliminary results in an animal model / 亚洲男科学杂志(英文版)

Surgical repair of complex posterior urethral disruptions remains one of the most challenging problems in urology. The efficacy of using a tissue expander capsule as an induced vascular bed to prefabricate axial vascularized buccal mucosa-lined flaps for tubularized posterior urethral reconstruction in a rabbit model was tested. The experiments were performed in three stages. First, silicone tissue expanders were inserted into the groin to induce vascularized capsule pouch formation. Next, buccal mucosa grafts were transplanted into the newly formed capsular tissue supplied by axial vessels for buccal mucosa-lined flap prefabrication. Then, circumferential posterior urethral defects were created and repaired with the buccal mucosa graft (Group 1), the capsule flap (Group 2), and the prefabricated capsule buccal mucosa composite flap (Group 3). After surgery, notable contracture of the tubularized buccal mucosa graft was observed in the neourethra, and none of the rabbits in Group 1 maintained a wide urethral caliber. In Group 2, the retrieved neourethra showed little evidence of epithelial lining during the study period, and the lumen caliber was narrowed at the 3-month evaluation. In Group 3, the buccal mucosa formed the lining in the neourethra and maintained a wide urethral caliber for 3 months. The capsule may serve as an induced vascular bed for buccal mucosa-lined flap prefabrication. The prefabricated buccal mucosa-lined flap may serve as a neourethra flap for posterior urethral replacement.

Tubularized urethral reconstruction using a prevascularized capsular tissue prelaminated with buccal mucosa graft in a rabbit model / 亚洲男科学杂志(英文版)

Tubularized graft urethroplasty fails largely because of inadequate graft take. Prefabrication of buccal mucosa lined flap has theoretical indications for constructing neourethra with an independent blood supply. The efficacy of using a tissue expander capsule as an induced vascular bed to prefabricate an axial vascularized buccal mucosa-lined flap for tubularized urethral reconstruction in a rabbit model was tested. The experiments were performed in three stages. First, silicone tissue expanders were inserted into the groin to induce vascularized capsule pouch formation. Next, buccal mucosa grafts were transplanted to the newly formed capsular tissue supplied by the axial vessel for buccal mucosa-lined flap prefabrication. Then, circumferential urethral defects were created and repaired by buccal mucosa graft (Group 1), capsule flap (Group 2) and prefabricated capsule buccal mucosa composite flap (Group 3). With retrograde urethrography, no rabbits in Group 1 maintained a wide urethral caliber. In Group 2, the discontinued epithelial layer regenerated at 1 month, and the constructed neourethra narrowed even though the lumen surface formed intact urothelial cells at 3 months. In Group 3, buccal mucosa formed the lining in the neourethra and kept a wide urethral caliber for 3 months. The capsule may serve as an induced vascular bed for buccal mucosa-lined flap prefabrication. The prefabricated buccal mucosa-lined flap may serve as a neourethra flap for circumferential urethral replacement.

Tubularized urethral reconstruction using a prevascularized capsular tissue prelaminated with buccal mucosa graft in a rabbit model / 亚洲男科学杂志(英文版)

Tubularized graft urethroplasty fails largely because of inadequate graft take. Prefabrication of buccal mucosa lined flap has theoretical indications for constructing neourethra with an independent blood supply. The efficacy of using a tissue expander capsule as an induced vascular bed to prefabricate an axial vascularized buccal mucosa-lined flap for tubularized urethral reconstruction in a rabbit model was tested. The experiments were performed in three stages. First, silicone tissue expanders were inserted into the groin to induce vascularized capsule pouch formation. Next, buccal mucosa grafts were transplanted to the newly formed capsular tissue supplied by the axial vessel for buccal mucosa-lined flap prefabrication. Then, circumferential urethral defects were created and repaired by buccal mucosa graft (Group 1), capsule flap (Group 2) and prefabricated capsule buccal mucosa composite flap (Group 3). With retrograde urethrography, no rabbits in Group 1 maintained a wide urethral caliber. In Group 2, the discontinued epithelial layer regenerated at 1 month, and the constructed neourethra narrowed even though the lumen surface formed intact urothelial cells at 3 months. In Group 3, buccal mucosa formed the lining in the neourethra and kept a wide urethral caliber for 3 months. The capsule may serve as an induced vascular bed for buccal mucosa-lined flap prefabrication. The prefabricated buccal mucosa-lined flap may serve as a neourethra flap for circumferential urethral replacement.

Preconstruction of the pars pendulans urethrae for phalloplasty with vaginal mucosa in female to male transsexuals / 中华医学美学美容杂志

Objective To investigate the feasibility of urethral prefabrication with vaginal mucosa in female-to-male transsexuals and to compare the urologic complications after penile reconstruction in female-to-male transsexuals between prefabrication group and forearm group.Methods Prefabrication of the neourethra with tubed vaginal mucosal graft was performed for 22 female-to-male transsexual patients from 2007 to 2016,while radial forearm flap,known as the traditional tube-within-tube method,was used to construct the neourethra for other 31 cases.Results All of the reconstructed penises survived completely and allowed the patients to urinate while standing in the prefabrication group.Phalloplasty by using the vaginal mucosal graft for urethroplasty significantly decreased the donor scar,the duration of the second operation and the incidence rates of urologic strictures,comparing with the forearm group (P＜0.05).Conclusions It is reliable to use the prefabrication of the neourethra with tubed vaginal mucosal graft in phalloplasty female-to-male transsexual patients.

Prefabrication of Axially Vascularized Bone by Combining β-Tricalciumphosphate, Arteriovenous Loop, and Cell Sheet Technique

The repair of bone defects poses a great challenge for reconstructive surgeons. Although the development of tissue engineering has exhibited promise in replacing damaged bone, the fabrication of large constructs with functional blood vessels remains an obstacle. From the orthopedic surgeon's point of view, the generation of axially vascularized bone, which can anastomose with the recipient vessel, might be a solution to this medical problem. In this study, we aimed to prefabricate an axially vascularized bone by combining a β-TCP scaffold, arteriovenous loop (AVL), and cell sheet in a bioreactor in vivo. Twelve rabbits were randomly allocated into two groups: the experimental group (presence of AVL) and the control group (absence of AVL). The constructs were explanted at 8 weeks postoperatively. The histomorphometric results showed 42.8±5.9% of the bone area in the AVL group and 26.6±3.5% in the control group. Similarly, vessel analysis revealed the average vessel density in the AVL group (12.5±3.3) was significantly more than that in the control group (6.1±1.5, p<0.05). Our research indicated that the combination of a β-TCP scaffold, AVL and cell sheet might engineer vascularized bone. This prefabrication strategy might facilitate clinical translation of bone tissue engineering in reconstructing large bone defects.

An experimental study for prefabrication of skin flap with frozen allogeneic bone / 中华显微外科杂志

Objective To research the feasibility of the prefabrication of skin flap with frozen allogeneic bone.Methods From November 2010 to July 2011,fifteen miniature pigs were randomly divided into three groups(n =5) according to different implanted positions.Rewarming,deep-frozen allogenic bone was implanted in subcutaneous tissue,subfascial compartment and muscle respectively.Emission Computed Tomography (ECT) was used in the 4th week,the 8th week and the 12th week postoperatively.Angiography and pathological examination was used in the 12th week.Results The difference of the result of ECT was statistically significant betweent the 4th week and the 8th week (P ＜ 0.05),and there was not statistically significant difference betweent the 12th week and the 8th week (P ＞ 0.05).Angiography showed that all allogeneic bone was vascularized in each group.Pathological examination showed that the vascularization and the inducing osteogenesis of the allogeneic bone which was implanted in the subfascial compartment or muscle was better than that in the subcutaneous tissue.Conclusion The deep-frozen allogenic bone can be used for the prefabrication of the bone-skin flap.

Reconstruction of Hard Palatal Defect using Staged Operation of the Prelaminated Radial Forearm Free Flap

PURPOSE: The radial forearm fasciocutaneous free flap is currently considered as the ideal free flap for reconstruction of mucosal and soft tissue defects of the palate. But the availability of stably attached oral and nasal mucosal lining is needed. In addition to this, for better operation field, operating convenience and esthetics, we planned a prelaminated radial forearm free flap. METHODS: A 64-year-old male patient was admitted due to a 4x4.5cm full through defect in the middle of the hard palate caused by peripheral T cell lymphoma with actinomycosis. In the first stage, the radial forearm flap was elevated, tailored to fit the hard palate defect, and then it positioned up-side down with split thickness skin graft. Two weeks later, the prelaminated radial forearm free flap was re-elevated and transferred to the palatal defect. One side covered with grafted skin was used to line the nasal cavity, and the other side(the cutaneous portion of the radial forearm flap) was used to line the oral cavity. RESULTS: The prelamination procedure was relatively easy and useful. The skin graft was well taken to the flap. After 2nd stage operation, the flap survived uneventfully. There was no prolapse of the inset flap into the oral cavity and the cutaneous portion of the flap was mucosalized. The procedure was very successful and the patient can enjoy normal rigid diet and speech. CONCLUSION: The use of prelaminated radial forearm free flap for hard palate reconstruction is an excellent method to restore oral function. Based upon the result of this case, microvascular free flap transfer with prelaminated procedure is a valid alternative to the prosthetic obturator for palatal defect that provides an improved quality of life. It should be considered as an integral component of head and neck cancer therapy and rehabilitation.

The structural study of prefabrication stress stent and the hemodynamics in percutaneous transhepatic portacaval shunt / 介入放射学杂志

Objective To present a preliminary latest procedure for portal hypertension and evaluate the technical feasibility and efficacy of portacaval shunt creation through the percutaneous transhepatic approach in order to make a hemodynamic comparison with that of the classic TIPS.Methods Thirty-eight patients with portal hypertension(36 men;mean age 57 years,range 32～73)were referred for PTPS procedure because of bleeding varices(n=36),intractable ascites(n=1),and hepatopulmonary syndrome(n=1).The severity of liver disease was classified as Child-Pugh B in 27 and C in 11.The PTPS was created by a percutaneous transhepatic puncture into right portal vein and then through left portal vein to the hepatic segment of IVC followed by a prefabrication stress stent-graft placement at the very site.Results Technical and functional success of 100% was achieved in all patients,without related complications.The postprocedural portal vein-IVC gradients mean 13 cmH_2O was achieved with the follow-up period mean 493 days.No recurrence of variceal bleeding and controlled refractory ascites were achieved,and still more with primary patency rate of the involved vascular structure up to 94.8% at 365 days,much better than classic TIPS. Conclusions Portacaval shunt creation using the prefabrication stress stent via percutaneous transhepatic technique is safe and feasible.The compact coincidence was obtained between the stent and the involved vessel with restoration of intrahepatic portal venous bemodynamics together with partial lowering of portal venous pressure and guaranteeing intrahepatic perfusion through right portal vein.It is also obviously to have postoperative prevention of shunt restenoses and lowering postoperative incidence of hepato-encephalopathy.

Functional reconstruction of dento-palatal and maxillary defect using staged operation of prefabricated scapular free flap and dental implants

The flap considered at first for the reconstruction of large maxillary defect, especially mid-face defect, is scapular free flap, because it provides ample composite tissue which can be designed 3-dimensionally for orbital, facial and oral reconstruction. In case of maxillary defect involving hard palate, however, this flap has some limitations. First, its bulk prevents oral function and physio-anatomic reconstruction of nasal and oral cavity. Second, mobility and thickness of cutaneous paddle covering the alveolar area reduce retention of tissue-supported denture and give rise to peri-implantitis when implant is installed. Third, lateral border of scapula that is to reconstruct maxillary arch and hold implants is straight, not U-shaped maxillary arch form. To overcome these problems, new concept of step prefabrication technique was provided to a 27-year-old male patient who had been suffering from a complete hard palate and maxillary alveolar ridge defect. In the first stage, scapular osteomuscular flap was elevated, tailored to fit the maxillary defect, particulated autologous bone was placed subperiosteally to simulate U-shaped alveolar process, and then wrapped up with split thickness skin graft(STSG, 0.3mm thickness). Two months later, thus prefabricated new flap was elevated and microtransferred to the palato-maxillary defect. After 6 months, 10 implant fixtures were installed along the reconstructed maxillary alveolus, with following final prosthetic rehabilitation. The procedure was very successful and patient is enjoying normal rigid diet and speech.

Effect of prefabrication on the survival of venous island flap

There are some attempts to improve the survival of venous island flap, such as delay procedure and pharmacological agents. This study includes prefabrication of vein which could enhance the survival of the venous island flap. The venous island flap was created by a branch of the central vein in rabbit auricle. At 1.5 cm away from the distal margin of the designed flap, the central vein was dissected and transferred under the random part of the future venous flap for 1 week. The survival of prefabricated venous flap was compared with unprefabricated flap 1 week after the flap elevation. The vasculature in the flap were also visualized by microfil cast. The results were as follows: 1. The prefabrication improved the survival of the venous flap significantly. 2. The transferred veins in the prefabricated flap were well visualized 1 week after the flap elevation. In conclusion, it is inferred that the prefabrication enhance the survival of the venous island flap.

Experimental study on the prefabricated tram flap of rabbits with enhanced neovascularization

There are occasions when standard techniques of reconstructive surgery for traumatic injury, tumor resection, and correction of congenital anomalies cannot be used as a result of the unavailability of tissues, absence of healthy vascular pedicle or excessive morbidity in donor area. It is established that autogenous skin, muscle, bone, and other composite tissue can retain their viability in varying degree as a prefabricated `flap with vascular pedicle implantation and the survival rate of these flaps has increased with tissue expansion or PGE1 infusion. The purpose of this study was to demonstrate the reliability of the secondary or prefabricated rectus abdominis musculocutaneous flap, and to evaluate the effect of the several factors on the survival routes of these flaps. Fifty New Zealand white rabbits weighing from 250 to 350 gm were used for the study. On the abdominal area bipedicled skin flaps are elevated as a random pattern flaps and were prefabricated using with rectus muscle. The fifty flaps were studied. They were divided into the five groups as follows; group I, 10 x4 cm classic axial pattern transverse rectus abdominis muscle (TRAM ) flaps were made as a control group (n = 10); groupII, 10 x4 cm random pattern bipedicled skin flaps were prefabricated using right rectus muscle with the delay procedure(n = 10); group III, 5 x4 cm prefabricated musculocutaneous flap were made same as group II on the right, side, tissue expansion was performed on the left side (n = 10); group IV, same procedure was performed as group II, and in addition postoperative intravenous infusion of PGE1 was given(n = 10); group V, same procedure was performed as group III, and in addition postoperative intravenous infusion of PGE1 and tissue expansion was performed(n = 10). Flap survival rates of each group were evaluated and compared. The following results were obtained: 1. Survival rates of prefabricated flaps were lower than that of classic axial pattern flaps regardless of using tissue expansion and PGE1 infusion(p < 0.05). 2. In making a comparison between flap with and without PGE1 infusion, survival rates of prefabricated flaps infused with PGE1 were higher than that of flaps without PGE1 infusion. 3. The prefabricated flaps managed with tissue expansion had higher survival rates than that of flaps without using tissue expansion. 4. The survival rates of prefabricated flaps managed in combination with tissue expansion and PGE1 infusion were significantly higher than that of other groups except control group. In conclusion, this study demonstrated the significance of combiring use of tissue expansion and PGE1 infusion in a prefabricated musculocutaneous flaps as a reliable method.

PREFABRICATION OF AURICLE WITH ABDOMINAL FLAP AND CARTILAGE IN RABBIT

Ear reconstruction with conventional modalities necessitates time consumming, expenses and multi-stage operations, a lot of time, and cost. Although single stage ear reconstruction with vascularized temporoparietal fascia has been developed, it is not always suitable due to precious surgery or trauma. Recently, prefabrication of a secondary island flap by transferring axial vessels and revascularizing target tissues has been attempted. The prefabricated composite secondary island flap can be transferred to other sites by micro-vascular anastomoses of the axial vessels in a second stage operation. In 10 rabbits, a 5x11cm sized bipedicled abdominal flap including panniculus carnosus muscle, concomitantly pedicled on the superficial inferior epigastric vessels was elevated. A 2.5x4cm sired auricular cartilage carried in the shape of a human auricle was tacked on the inner surface of the flap, and the flap was tubed with 4-0 nylon sutures. The abdominal donor wound was primarily closed. At 17 days after elevation, the tubed abdominal flap was trimmed into a human ear shaped composite island flap connected only by the superficial epigastric vascular bundles, and the caudal pole was sutured back to the abdominal skin. Skin surface fluorometry was performed to assess the degree of skin perfusion. The percentage of skin flap survival was recorded 14 days later. The mean Dye Fluorescence Index was 68 14% of normal. Almost 100% of the skin was survived in all rabbits. The histologic study revealed infiltration of homogeneous granulation tissue between the cartilage and flap. The grafted cartilage was healthy and showed normal appearance. Using this principal of ear prefabrication through delay and revascularization of various tissues as an island composite flap, it can be applied in humans with scaring of the temporo-parietal region.