How Can We Achieve Infection‐Resistant Percutaneous Energy Transfer?

Clinical records show ever increasing functional times of rotary blood pumps implanted in patients. With longer functional time, the problem of driveline infection is becoming more urgent. No material or scaffold has been found, which allows a permanent and stable ingrowth of skin cells that would prevent (pathogenic) germs entering the body. Usually, the epithelial cells die at the exit site and new cells form a sulcus around the driveline, which grows deeper and finally becomes infected. The purpose of this project is to present a solution to this problem by elaborating a new mechanism, the active skin-penetrating device. The device is composed of a tube with a 5-mm diameter, a protective sleeve that surrounds the catheter exit site, and an active traction device. The protective sleeve is made of thin polyurethane covered with polyethylenterephtalat (PET, i.e. Dacron) fibers to permit the attachment of keratinocytes, similar to the standard driveline. The active traction device exerts a constant pull on the protective sleeve. The ingrown keratinocytes slowly give way and the protective sleeve gradually moves out of the body at a rate of a few millimeters per week. Meanwhile, the keratinocytes transform into horny cells and are then shed as in natural skin. Therefore, the formation of a sulcus is avoided, and the protective sleeve remains infection-free. In a first proof of the concept, four of the new devices and 10 control devices were implanted in goats. The devices remained infection-free for a period of 420 days, whereas four of the 10 control devices became infected. On the basis of these experiments, the active skin-penetrating device has been further developed and is being tested again in goats in a refined version. The results so far indicate that with the active-skin penetrating device an infection-resistant percutaneous energy transfer can be achieved for a prolonged period of time.     

Selected best demonstrated practices in peritoneal dialysis access

Many burdensome interventions that adversely affect the utilization of peritoneal dialysis as renal replacement therapy and patient satisfaction with this treatment modality can be avoided by early peritoneal access placement with embedded catheters, implantation techniques that preempt common catheter complications, and the use of access devices that provide flexibility in exit site location. Catheter embedding consists of subcutaneously burying the external limb of the catheter tubing at the time of the insertion procedure. Interval exteriorization of the catheter is performed when dialysis is needed. Earlier commitment by patients to peritoneal dialysis can be achieved by elimination of catheter maintenance until dialysis is necessary. Catheter embedding is a practical strategy to avoid temporary hemodialysis with vascular catheters and reduces stress on operating room access by allowing more efficient scheduling as non-urgent procedures. Laparoscopic catheter placement enables proactive techniques not available to other conventional insertion methods. These techniques include rectus sheath tunneling to prevent catheter tip migration, selective prophylactic omentopexy to prevent omental entrapment, selective resection of epiploic appendages to prevent catheter obstruction, adhesiolysis to eliminate compartmentalization, and diagnosis and simultaneous repair of previously undiagnosed abdominal wall hernias. Both standard and extended 2-piece catheter systems are necessary to customize the peritoneal access to a variety of body configurations. Catheters should be able to produce lower abdominal, mid-abdominal, upper abdominal, and upper chest exit site locations that facilitate management by the patient without sacrificing deep pelvic position of the catheter tip or resulting in excessive tubing stress during passage through the abdominal wall.     

Development of an infection-resistant LVAD driveline: a novel approach to the prevention of device-related infections.

BACKGROUND: Infection remains the single most important challenge to extended left ventricular assist device (LVAD) use and often arises from the percutaneous driveline exit site. We evaluated the ability of an LVAD driveline prototype impregnated with chlorhexidine, triclosan, and silver sulfadiazine to resist bacterial and fungal colonization. METHODS: The spectrum and duration of antimicrobial activity were evaluated in vitro by daily transfer of driveline segments embedded on agar plates inoculated with 10(8) colony-forming units (CFU) of Staphylococcus aureus (S. aureus), Staphlococcus epidermidis, Enterobacter aerogenes, Psuedomonas aeruginosa, and Candida albicans, and then measuring zones of inhibition around the sample subsequent to 24 hours of incubation at 37 degrees C. Antimicrobial activity was demonstrated against all organisms for greater than 14 days, and for over 21 days for gram-positive bacteria. To demonstrate in vivo efficacy of the treated driveline, 3-cm segments of driveline were implanted in the dorsal and ventral surface of rats. The exit site was inoculated with 10(6) CFU of S. aureus. After 7 days, driveline segments were aseptically explanted and assayed for bacterial colonization and retention of antimicrobial activity. One hundred percent of control segments were colonized (10(5) CFU S. aureus/cm) as against 13% of the test explants (< or = 330 CFU/cm; p < 0.0001). RESULTS: Subcultures of the insertion site and driveline pocket tissue resulted in 10(3) to 10(5) CFU per swab culture for control rats and 0 to 10(2) CFU/swab for test animals. Test drivelines retained 80% of anti-S. aureus activity. Gross and histological examination of the driveline and surrounding pocket revealed minimal tissue reactivity with positive signs of tissue ingrowth. CONCLUSION: An antimicrobial driveline may prevent early infections and facilitate ingrowth of tissue to provide long-term stability and protection against late infection.     

Laser-assisted reconstruction of the oculomotor nerve: experimental study on the feasibility of cranial nerve repair

In this experimental study the feasibility of microsurgical laser-assisted repair of the oculomotor nerve in the cat was investigated. The 3rd cranial nerve was explored after a temporobasal craniectomy from its exit at the brain stem to its entrance into the cavernous sinus and transected. The cut nerve ends were loosely reapproximated and welded together with a CO2 milliwatt laser using a power setting of 80 to 90 mW and a spot size of 150 mu. Regeneration of the oculomotor nerve within an observation period of 12 months as assessed by weekly examination of the pupil diameter was excellent in 4 animals and satisfactory in 2. In the two control groups consisting of 6 animals in which the nerve reconstruction had been performed with fibrin glue or by simple nerve reapproximation minimal nerve regeneration could be observed only in one animal. The histomorphological examinations revealed good regeneration across the laser anastomosis including new formation of a perineural sheath without any significant scarring effect or constriction at the anastomotic site. It is concluded that the CO2 milliwatt laser might be a useful tool for the microsurgical repair of cranial nerves and should possibly be incorporated into the neurosurgical armamentarium of reconstructive cranial nerve surgery.     

An Animal Study of a Newly Developed Skin‐Penetrating Pad and Covering Material for Catheters to Prevent Exit‐Site Infection in Continuous Ambulatory Peritoneal Dialysis

Because currently available peritoneal dialysis catheters are not sufficiently biocompatible with the skin and subcutaneous tissue at the site of penetration, exit‐site infection due to pericatheter pocket formation caused by epidermal downgrowth over a long period of time has increasingly become a problem. We developed a new, biocompatible, segmented polyurethane porous material and devised a novel skin‐penetrating pad, the form and material of which we optimized for application in peritoneal dialysis catheters. For the extent of tissue ingrowth into this porous material to be examined, test materials with different pore diameters were inserted into hollow silicone tubes and implanted in the subcutaneous tissue of a goat. Four weeks later, the tubes were extracted, and, after the extent of granulation tissue ingrowth was measured, histopathological evaluation was made. Our novel skin‐penetrating pad has three disklike layers of the segmented polyurethane material with different pore sizes, into the center of which a polyurethane catheter is inserted. These pads were implanted in the skin of a goat and clinically observed over a 2‐year period, after which they were extracted and histopathologically analyzed. In accordance with actual clinical procedures, a commercial CAPD catheter equipped with our skin‐penetrating pad was left indwelling in a goat for 4 months, and the performance of the pad was evaluated after repeated periodic infusion and drainage of the dialysate in and out of the abdominal cavity. There was no inflammation of the ingrown tissue in the pores of the segmented polyurethane material as well as the surrounding tissue, which indicated favorable tissue biocompatibility. The extent of tissue ingrowth was greater as the pore size of the material was larger, and the tissue tended to be mature, mainly consisting of collagenous fibers. The skin‐penetrating pad using the porous material, of which tissue ingrowth was thus optimized, tightly adhered to the goat skin throughout the 2‐year experimental period without any special wound care such as cleansing or disinfection. The performance of the skin‐penetrating pad was similarly favorable when attached to a commercial continuous ambulatory peritoneal dialysis catheter. The newly developed segmented polyurethane porous material had excellent tissue biocompatibility and tissue ingrowth. The skin‐penetrating pad devised by using this porous material did not cause epidermal downgrowth, suggesting that it may be effective for the prevention of exit‐site infection.     

The usefulness of basic fibroblast growth factor for radiation‐exposed tissue

A high dose of ionizing external radiation damage to the skin and soft tissue results in changes in function as well as in the general body condition. Once radiation surpasses the tissue safety or survival level, progressive alteration in the damaged tissue results in tissue loss and then flap loss. Local expression and action of stem cells or local growth factors in the irradiated tissue is mitigated, and external administration is sought to investigate the possibility of skin and soft tissue survival after an elevating flap. Basic fibroblast growth factor (bFGF) is primarily considered as a potent angiogenic growth factor. In burns, resurfacing with a dermal component is required, and bFGF stimulates wound healing and enhances human skin‐derived mesenchymal stem cells under serum‐free conditions in a dose‐dependent manner. Thirty‐five male, 4‐ to 8‐week‐old CLAWN miniature pigs received radiation exposure to assess the effectiveness of bFGF in terms of the progressive clinical course relevant to human skin and soft tissue. At 2 weeks following 10‐Gy irradiation, tissue was preserved in the group receiving subcutaneous placement of a round‐type tissue expander and bFGF. The expander plus bFGF group demonstrated significantly greater dermo‐epidermal proliferation than the radiation alone, radiation plus bFGF, or expander plus radiation plus vehicle‐solution groups, and new blood vessel formation was significantly increased in the expander tissue with bFGF after irradiation (p < 0.01). Electron microscopy revealed that tissue with expander and bFGF maintained more stable skin adnexae with preserved intact epidermis and dermis. Thus, bFGF improved and maintained the tissue viability after immediate irradiation in the skin and soft tissue.     

Postauricular percutaneous power delivery for permanent mechanical circulatory support

OBJECTIVE: Percutaneous driveline infection continues to detract from both quality and length of life in patients with a left ventricular assist device. We have pursued an alternative route by using a skull-mounted percutaneous pedestal similar to cochlear implant technology. We have now used this method in patients implanted with the Jarvik 2000 heart (Jarvik Heart, Inc, New York, NY) as destination therapy for end-stage (New York Heart Association class IV) heart failure. METHODS: Four men with cardiomyopathy aged 61 to 72 years received the Jarvik 2000 heart with postauricular power delivery for permanent mechanical circulatory support. The power cable was brought through the second posterior intercostal space and routed through the neck to a percutaneous titanium implant screwed to the skull. This joins with the cable to the external controller and battery. RESULTS: In 3 patients the pedestal healed well and remained free from infection up to 1 year. The system was user friendly, and the whole external apparatus is exchangeable. The second patient had a subdural hematoma. This caused us to improve the preparation and modify the implant procedure. CONCLUSION: For widespread use, permanent implantable circulatory support requires a reliable, user-friendly device with freedom from powerline infection. Our early experience with the Jarvik 2000 heart suggests that rigid fixation and the vascularity of scalp skin promote healing and reduce the risk of driveline infection.     

皮肤扩张器法治疗手套状皮瓣术后重度虎口挛缩

目的探讨采用皮肤扩张器治疗手套状皮瓣术后重度虎口挛缩畸形的临床疗效。方法自2017年2月至2018年10月,四川现代医院手外科采用皮肤扩张器治疗7例手部手套状皮瓣术后导致重度虎口挛缩的患者。一期在皮瓣下埋置50~100 ml的皮肤软组织扩张器1个,术后7~10 d开始注入生理盐水,5~10 ml/次,2次/周,扩张1~2个月;扩张后静置约2周行二期手术,取出皮肤扩张器,开大虎口,利用扩张的皮肤修复虎口创面。结果7例患者术后扩张皮瓣成活良好,切口均一期愈合。随访6~19个月,虎口开大60°~85°,皮瓣血运及质地良好。结论采用皮肤扩张器治疗手部手套状皮瓣术后虎口挛缩畸形,操作简单,是一种解决重度虎口挛缩皮肤不足的较好方法。     

自体皮源奇缺条件下瘢痕挛缩畸形的晚期临床修复

目的寻找对烧伤后畸形伴自体皮源奇缺患进行晚期修复的新方法。方法5例特重度、特大面积烧伤患治愈后伴较严重畸形，且自体皮源奇缺。采用柔软成熟的瘢痕皮肤作为修复的皮源，用扩张器扩张瘢痕皮肤后，切取中厚瘢痕皮片进行修复；不宜行瘢痕皮肤扩张术时，切取刃厚瘢痕皮片与异体脱细胞真皮基质组成复合皮进行修复。观察两种方法的疗效。结果所移植的扩张瘢痕皮片和复合皮均成活，功能和外形恢复良好，远期疗效近似正常自体中厚皮移植。结论采用不同厚度的瘢痕皮片修复烧伤畸形是可行的，可扩大自体皮源。此法对于皮源奇缺的瘢痕患尤其适用。     

Flexor tendon repair in "No Man's Land" an experimental study.

Twenty-five fingers of seven monkeys were used for an experimental study of a new concept of flexor tendon repair in "No Man's Land". Microsurgical aids were used to shift distally a sleeve of healthy flexor tendon sheath to cover the site of the repaired flexor tendon. There was a low success rate due to technical difficulties in the immobilisation of the monkey fingers. Where the finger was successfully immobilised the results were encouraging.     

上臂内侧扩张皮瓣修复面部瘢痕挛缩

目的探讨上臂内侧扩张皮瓣面部瘢痕挛缩的方法及效果。方法采用上臂内侧扩张皮瓣修复面部瘢痕挛缩17例。结果本组皮瓣面积(10 cm×8 cm)~(15 cm×9 cm),移植皮瓣全部成活。7例随访3个月~5年,皮瓣外形良好,色泽与面部皮肤相近,供瓣区遗留瘢痕较小。结论上臂内侧扩张皮瓣修复面部瘢痕挛缩效果良好,虽所需时间长,且需强迫体位固定,但仍不失为面部整形修复的可选之法。     

扩张皮瓣整复颈部瘢痕挛缩的技巧与美学问题

目的：探讨采用扩张皮瓣整复颈部瘢痕挛缩的技巧与相关的美学问题。方法：根据颈部瘢痕的部位,范围和病灶周围情况选择扩张器的数量、容量与埋植部位,注水过程中采用扩张器托以防止其移位,用改良的下颌部软组织瓣重建颏部与下颌缘关加深颌颈角,借助打包包扎法保证扩张皮瓣成活。结果：除1例因血肿改用全厚皮片移植治疗外,所有扩张皮瓣与移植皮片均100％成活,术后功能满意,外形良好,达到了预期的美学要求,结论：以美学理论为指导,结论适当的手术技巧有助于颈部瘢痕挛缩形术后功能与形态的恢复。     

S‐IV‐03 Ectopic Bone Formation Accelerated by Human Mesenchymal Stem Cells and Osteogenic Cytokines via Nutrient Vessel Injection in Nude Rat

Critically larger bone and skin defects often lack the enough nutrient blood supply to induce normal wound healing. Additionally, deteriorated environment such as poor vascularity due to the hard fibrosis after irradiation or extensive tissue loss due to the highly damaged tissue or severe bacterial contamination, leads to finding another donor sites or another methods to repair. Potential free vascularized flaps are widely accepted for reconstruction purpose, however, the donor‐site morbidity is sometimes concerned and its clinical application may be limited. Tissue engineered tissues are now most actively investigated and partially clinically appropriate for use. In order to assist the bone wound healing, the human mesenchymal stem cells (hMSCs), wrapped with the abdominal fascial flap, which is nutrient of superficial epigastric vascular systems in bone, and the full‐thickness dorsal defect covered by artificial skin substitute as a carrier in skin, are used as cell source with potential differentiation with specific cytokines in a nude rat model for eliminating T cell immunity. The hMSCs and osteogenic cytokines such as bone morphogenetic protein‐2 (BMP‐2) and basic fibroblast growth factor (bFGF) were intra‐arteriallly injected and incubated for 10 minutes and then the gelatin‐carrier were wrapped with the abdominal superficial fascia and investigated for the subsequent experiments. The heterotopic bone formation was most significantly observed in 4 weeks after injection and this may be used clinically to enhance the compromised bone healing.     

软组织扩张术在不规则表浅性瘢痕治疗中的应用

目的:探讨瘢痕与正常皮肤相间的不规则表浅性瘢痕的治疗方法。方法:对12例不规则表浅性瘢痕的患者采用皮肤软组织扩张术治疗。一期在瘢痕与正常皮肤下埋置一个扩张器,使瘢痕组织与正常皮肤共同扩张,二期切除瘢痕。结果:12例患者瘢痕均一次彻底切除。一期手术无扩张器外露、感染、切口愈合不良及扩张皮瓣血运不良等并发症发生;二期手术伤口均I期愈合,无血肿、感染及皮瓣坏死等并发症。结论:在瘢痕与正常皮肤相间的组织下埋置皮肤软组织扩张器,使瘢痕组织和正常皮肤组织同时扩张,可以最大限度地利用正常皮肤,使之得到有效扩张,有利于瘢痕的切除。     

圆形皮肤扩张器在面部旁正中瘢痕修复中的应用

目的:探讨应用圆形皮肤扩张器扩张皮瓣修复面部旁正中瘢痕的效果。方法:2014年1月至2019年5月收治面旁正中部瘢痕患者30例,于瘢痕外侧颧颊部埋置圆形皮肤扩张器,经注水扩张后,设计推进或异位扩张皮瓣修复面旁正中瘢痕。结果:30例患者完成扩张,注水扩张中3例发生感染经腔内灌洗引流控制,4例并发血肿行血肿清除术。30例面旁正中瘢痕成功修复,其中11例伴下睑外翻者完全矫正7例、改善4例;伴上唇外翻、口角歪斜、鼻翼畸形者均得到不同程度的改善。随访6~12个月,患者对瘢痕修复效果较满意。结论:选择圆形皮肤扩张器修复面旁正中瘢痕,皮肤利用率高、皮瓣设计方便、修复效果好。     

组织扩张器在额部皮瓣鼻再造术中应用探讨——临床报道10例

目的　减少扩张后的额部皮瓣再造鼻引起的严重继发挛缩 ,探讨组织扩张器在额部皮瓣鼻再造术中的应用。方法　对发际高的患者直接采用额部皮瓣行鼻再造 ,额部供区植皮 ,同期额部置入扩张器 ,Ⅱ期修复额部植皮区瘢痕。结果　共治疗了 1 0例患者 ,术后鼻外形良好 ,并对其进行随访 ,最长 3年 ,效果满意。结论　该方法证实具有远期鼻挛缩较少、额部瘢痕不明显等优点 ,临床效果良好     

Topical Polymyxin‐Trimethoprim Prophylaxis May Decrease the Incidence of Driveline Infections in Patients With Continuous‐Flow Left Ventricular Assist Devices

This retrospective cohort study evaluated the effect of topical polymyxin‐trimethoprim (poly) prophylaxis on the incidence of driveline infections (DLIs) in patients with continuous‐flow left ventricular assist devices. All 84 cases implanted 2005–2014 with device support ≥30 days were reviewed; support ranged 1 m–5.2 yrs. Beginning 2008, poly was applied to the exit site with dressing changes. Sixty‐five patients received poly (poly group) for duration of follow‐up, 19 did not (no‐poly); group baseline characteristics were similar. No patient developed side effects from poly. Nineteen DLIs (10 in no‐poly) occurred; not using poly was a risk factor. 89% of poly group DLIs were superficial, 4 were culture‐negative. DLI‐related bacteremia occurred in 11% of no‐poly group and 0% of poly group. Compared with no‐poly, poly group demonstrated improved freedom from DLI by Kaplan‐Meier analysis (P < 0.0001) and a 75% lower overall and 95% lower deep DLI incidence (P ≤ 0.001). Deep DLIs occurred in 31.6% of no‐poly vs. 1.5% of poly patients (P = 0.0004), although mean support duration (1 yr) and % support >1 yr (38%) were similar. These findings, which should be confirmed with larger comparative studies, suggest that topical polymyxin‐trimethoprim prophylaxis may be effective in preventing DLIs.     

Improved aftercare in LVAD patients: Development and feasibility of a smartphone application as a first step for telemonitoring

For the success of the treatment with a left ventricular assist device (LVAD), both adequate self-management by the patient and an optimum level of support from the implanting hospital are crucial. A smartphone application has recently been developed within the framework of a European research project for the close monitoring of LVAD patients in order to improve upon their current aftercare situation. Using this new tool, different relevant parameters (eg, weight, international normalized ratio [INR], medication, LVAD parameters, symptoms, and photos of the driveline exit) can be sent daily or as required to a corresponding clinical application at the hospital for evaluation. The objective of this study was to monitor the functionality, acceptance, and usability of this smartphone application in LVAD patients. Prospective single-center study: in total, 13 patients (60 ± 7 years, 92% male, 1027 ± 653 days after LVAD implantation) were requested to test the application for approx. 4 weeks. At the end of the study, all entered data were evaluated and the patients were questioned regarding the acceptance and the usability. During the study period of mean 34 ± 8 days, a total of 453 data records (mean 35 ± 7 per patient) arrived at the hospital. In addition, a total of 19 photos of the driveline exit site were also sent via smartphone. The clinical application registered a total of 160 conspicuities. These comprised 126 INR deviations (target range 2.3-2.8) and 34 symptoms (mainly nosebleeds). The smartphone application functioned reliably, was well received by the patients and was graded highly for acceptance and usability. The results show that smartphone applications can definitely be used to improve aftercare in LVAD therapy in selected patients. Long-term studies are now needed to investigate the extent to which complications can be prevented, healthcare costs reduced, and quality of life increased.     

应用超量扩张术修复大面积面颈部瘢痕

目的：探讨延长扩张时间、增大扩张量的皮肤软组织扩张术的临床效果。方法：应用皮肤软组织扩张术修复面颈部瘢痕切除后创面25例,手术分两期进行,Ⅰ期手术：在需要修复的瘢痕组织临近的正常皮肤上设计埋置扩张器的大小、形状及埋置方式,扩张器容量为100～400ml,扩张时间为3～6个月,扩张量为额定容量的2～5倍;Ⅱ期手术：取出扩张器,切除瘢痕,利用扩张皮瓣转移修复创面。结果：全部病例均获得满意效果,随访3个月至10年,皮瓣平整,外观色泽、质地均佳。结论：延长扩张时间,增加扩张量可以产生更多的额外皮肤,修复大面积面颈部瘢痕效果良好。     

皮肤外扩张器的研制与临床应用

我们自１９９３年６月起，开始研制皮肤外扩张器，其原理为通过持续对皮肤进行牵引，以获得＂额外＂皮肤组织。经临床应用３８例，表明本方法具有以下优点：操作简单，不需手术埋置扩张器，并发症少，安全可靠，并可提供准确的皮肤扩张面积数据。其中１８例已随访６个月，疗效稳定，外形及功能满意。为临床修复组织缺损提供了一种新途径。