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Biomedical subjects

P Mailänder

Publications and source records attributed to P Mailänder.

At least 19 recordsLinked to original sources
PubMed2007

[Bridging peripheral nerve defects by means of nerve conduits].

BACKGROUND: The nerve autograft is the gold standard for the reconstruction of peripheral nerve defects. In short gaps, nerve repair by means of tubulization has become an alternative. This technique is discussed based on the current literature and our own experience. PATIENTS AND METHODS: Nerve reconstruction by means of tubulization was performed in 11 patients. Nerve gaps in the hand of up to 18 mm were reconstructed. Sensibility was assessed using static and dynamic two point discrimination (s-, d2PD) and monofilament testing 3, 6 and 12 months postoperatively. RESULTS: Three out of 11 patients complained of a temporary foreign body sensation in the area of the implant; this was persistent in one case. Four out of six patients showed excellent results with s2PD of 15 mm, S0), another poor sensibility (s2PD 15 mm, S3). D2PD and monofilament testing confirmed these results. CONCLUSIONS: Nerve reconstruction by means of tubulization seems to be a suitable method for certain indications in the reconstruction of short defects of digital and palmar nerves. Donor site morbidity can be avoided. Similarly to nerve transplantation, the operation requires microsurgical skills.

Absorbable Implants↗
PubMed2006

[Clinical impact of operative multidisciplinarity for severe defect injuries of the lower extremity].

BACKGROUND: The aim of this study was to examine the impact of our multidisciplinary therapeutical concept (MTC) on the clinical outcome in posttraumatic defect injuries of the lower extremity. PATIENTS AND METHODS: Since 1999, we have performed a free tissue transfer in 37 patients. In group 1 (n = 21), our MTC was started more than two weeks (range: 17 to 83 days) after trauma and in group 2 (n = 16) within two weeks (range: four to twelve days) after trauma. Both groups were comparable with respect to trauma severity. RESULTS: 100 % patients of group 1 and 25 % patients of group 2 had clinical and microbiological manifestations of wound infection after admission in our clinic. Significantly more operations were necessary in group 1 compared to group 2 (7.3 +/- 2.6 versus 2.9 +/- 0.8; p < 0.05), until definitive wound closure could be achieved. The postoperative course was uneventful in 35 cases. All injured extremities could be salvaged. Multistaged bone reconstructions by means of spongious or tricortical bone from the iliac crest were successful in all cases. Hospital stay after admission to our clinic was significantly longer in group 1 compared to group 2 (57 +/- 12 days versus 31 +/- 7 days, p < 0.05). CONCLUSIONS: In our study, the early start of MTC significantly reduced the risk for wound infection, the number of surgical revisions before definite wound closure and time until bone and wound healing was completed.

Adolescent↗
PubMed2005

A technique to detect and to quantify fasciocutaneous blood vessels in small laboratory animals ex vivo.

PURPOSE: A microangiographical technique is described, which allows visualization of small and capillary blood vessels and quantification of fasciocutaneous blood vessels by means of digital computer analysis in very small laboratory animals. MATERIALS AND METHODS: The left carotid artery of 20 nu/nu mice was cannulated (26 gauge) and a mixture of gelatin, bariumsulfate, and green ink was injected according to standardized protocol. Fasciocutaneous blood vessels were visualized by digital mammography and analyzed for vessel length and vessel surface area as standardized units [SU] by computer program. RESULTS: With the described microangiography method, fasciocutaneous blood vessels down to capillary size level can be clearly visualized. Regions of interest (ROIs) can be defined and the containing vascular network quantified. Comparable results may be obtained by calculating the microvascular area index (MAI) and the microvascular length index (MLI), related to the ROIs size. Identical ROIs showed a high reproducibility for measured [SU] < 0.01 +/- 0.0012%. CONCLUSION: Combining microsurgical techniques, pharmacological knowledge, and modern digital image technology, we were able to visualize small and capillary blood vessels even in small laboratory animals. By using our own computer analytical program, quantification of vessels was reliable, highly reproducible, and fast.

Angiography↗
PubMed2005

[Regenerative medicine and plastic surgery].

Regenerative medicine recently evolved as a new medical field that includes tissue engineering, cell/system biology, nanotechnology, pharmacology, stem-cell biology, and bioengineering. Regenerative medicine targets new forms of therapy to promote and support the intrinsic, autologous, regenerative potential of human biological systems. All fields of surgery have profited from these developments, and spectacular experimental results and clinical benefits have been obtained. Plastic surgery has shown interest in regenerative medicine due to its focus on reconstructive surgery. Early on, several interdisciplinary experimental working groups were founded including plastic surgery. This overview takes a closer look at common experimental and clinical results of regenerative medicine and plastic surgery.

Animals↗
PubMed2005

[Mechanisms and therapeutic strategies for the induction of angiogenesis in plastic surgery].

Plastic Surgery has been focussing on wound healing and therefore also on angiogenic regulatory mechanisms since many years. Nowadays most of the pioneering work including different plastic surgical techniques like tissue transfer and microsurgery are surgical standard. But only since 10 to 15 years we have tools and methods to investigate the molecular mechanisms of functional angiogenesis in vivo. This article presents some mechanisms and therapeutic strategies for angiogenesis, which can be applied both clinically and experimentally in plastic surgery.

Adult↗
PubMed2005

[A microangiography technique to quantify fasciocutaneous blood vessels in small laboratory animals].

PURPOSE: A microangiographic technique is described, which allows visualization of small blood vessels with a diameter of approximately 20 microm and quantification of fasciocutaneous blood vessels by means of digital computer analysis in very small laboratory animals. METHOD: The left carotid artery of 45 nu/nu mice was cannulated (26 gauge) and a mixture of gelatine, barium sulfate and green ink was injected according to standardized protocol. Fasciocutaneous blood vessels were visualized by digital mammography and analyzed for vessel length and vessel surface area as standardized units (pixel) by computer program. RESULTS: With the described microangiography method fasciocutaneous blood vessels can be clearly visualized. Regions of interest (ROIs) can be defined and the containing vascular network quantified. Identical ROIs showed a high reproducibility for measured unit (pixel) < 6.5 +/- 2.4 %. By the use of digital image, processing the quantification of vessels was reliable, reproducible and fast. CONCLUSION: Combining microsurgical techniques, pharmacological knowledge and modern computer imaging analysis systems, we were able to visualize and quantify blood vessels with a diameter of approximately 20 microm even in small laboratory animals.

Angiography↗
PubMed2004

[Positron emission tomography (PET) in soft-tissue sarcoma].

Positron emission tomography (PET) uses the significantly increased glucose metabolism to differentiate malignancies from healthy tissue. This method is well established in the oncologic diagnostics of solid epithelial tumours and also in breast cancer. In low-grade soft tissue sarcomas specificity and sensitivity are limited, however. Not only conventional systems, but also dual headed coincidence cameras requiring considerably less technical and economical expenditure can be used to produce PET-scans. We have studied the outcome of this technology in 13 patients with different types of soft-tissue sarcoma. It is our impression that both conventional and gamma camera based PET-systems result in similar results in soft-tissue sarcoma. Furthermore, in one of the cases presented, PET was able to detect metastases considerably earlier than conventional radiography.

Adult↗
PubMed2003

A rare vasoproliferative lesion: angiolymphoid hyperplasia with eosinophilia of the hand.

Angiolymphoid hyperplasia with eosinophilia (ALHE) is a rare vasoproliferative lesion of uncertain aetiology, involving the skin and subcutaneous tissue. The predilection of the tumour-like lesion is for the head and neck region. Radical surgical excision is still regarded as the most effective treatment. We present the case of a 33-year-old female with ALHE of the right hand. Preoperative MRI and angiography demonstrated involvement of the fourth and fifth rays, with complete occlusion of the ulnar artery, and a small lesion at the level of the metacarpophalangeal joint of the index finger. Complete tumour excision could not be achieved without resection of the fourth and fifth rays. One year postoperatively, there were no clinical signs of recurrence. The patient refused any further invasive diagnostic and follow-up examinations. Angiolymphoid hyperplasia of the hand is a rare disease, and patients should undergo early surgical treatment to achieve complete excision of the lesion.

Adult↗
PubMed2001

Computer-guided microsurgery: surgical evaluation of a telerobotic arm.

A new telerobotic arm was evaluated in different microsurgical procedures. The system consisted of a robotic arm bearing a microsurgical forceps controlled by a joystick-like master unit operated by the surgeon's hand. The robotic arm functioned as an operating as well as assisting instrument. Advantages of the system were its precise functioning, which was especially important when tissue or instruments had to be held for a longer period of time, as well as its ability to replace an assisting person to some extent. Deficiencies of the system were its 10-min startup, the spatial conflict with in the operative field, and the poor rotation of the robotic tip. In some procedures, the telerobotic arm could replace the standard microsurgical instrument guided by the surgeon's second hand; in other maneuvers it could function as the surgeon's third hand with precision and void of tremor.

Anastomosis, Surgical↗
PubMed2001

Modified dorsalis pedis flap for coverage of a pretibial pressure sore after hip rotationplasty.

Rotationplasty is a well-established procedure after total femur resection, especially in children. Rehabilitation is superior to disarticulation of the hip or hemipelvectomy because patients regain hip and knee function.(1) A tight fit of the prosthetic shaft is essential. The pretibial area has a low physiological resistance to pressure and shear forces, and is thus at increased risk of developing pressure-related complications. Skin defects with exposure of skeletal elements require flap coverage. The dorsalis pedis flap is one of the surgical options available for skin coverage of the proximal anterior leg. It can be rotated to cover almost any site on the anterior aspect of the leg if the pedicle is mobilised up to the anterior tibial artery.(2)Since donor site complications are common, this flap has few indications.(3)

Antineoplastic Agents↗
PubMed2001

[Treatment costs in initially underestimated infections of the hand].

Summary. Infections that develop as a complication of minor injuries to the hand, frequently are underestimated by the patient or by the physician initially consulted. Between 1990 and 2000, we have treated 172 in-patients as a result of this underestimation. In a retrospective study we have tried to evaluate the economic consequences. According to our results, treatment costs of 210,000 D-Mark could have been saved, if adequate treatment had been initiated on time.

Adolescent↗
PubMed2000

[Gene therapy possibilities in plastic surgery].

Advances in gene technologies have meanwhile reached plastic surgery. Important contributions in this field (which are not all included in the paper) come not only from plastic surgeons, but also from neighboring specialities like dermatology, trauma surgery, orthopedics and vascular surgery. The uniting principle for all this work is improving wound healing and reconstructing tissue defects taking into consideration functional and aesthetic aspects. Gene-therapy is gaining further importance in the clinical field of plastic surgery. In this regard, every clinician has to be aware of the fact that progress in experimental and experimental-clinical work will be achieved only with the help of basic science. On the other hand, basic science needs the clinical input to get relevant patient-oriented studies started. Further intensive cooperation between clinicians and basic scientists is therefore mandatory. In plastic surgery, 2 years ago we founded a forum called ECSAPS (European Conference of Scientists and Plastic Surgeons), which takes place in European city every year.

Animals↗
PubMed2000

[Does tissue perfusion after free microvascular tissue transplantation remain autonomous?].

In a retrospective study, including 60 patients, after free latissimus dorsi transplantation (FLDT) to the lower leg, we found persistent pedicle blood flow up to ten years postoperatively. After uncomplicated FLDT, the pedicle supported the flap in all cases. After complicated FLDT (hematoma, thrombosis, infection) only 50% of all flaps after ten years were perfused by the vascular pedicle.

Adolescent↗
PubMed2000

Flap perfusion after free musculocutaneous tissue transfer: the impact of postoperative complications.

In a previous study, the authors found persistence of pedicle blood flow up to 10 years after uncomplicated free latissimus dorsi transfer. In this study, the impact of postoperative complications (hematoma, thrombosis, infection) and successful surgical revision was tested. Since 1982, more than 1200 free tissue transfers have been performed at the authors' institution (Hannover Medical School). Of these, the authors selected two groups of 30 patients each who had received a free latissimus dorsi transfer to the lower leg without microsurgical nerve coaptation for wound coverage. All patients included in this study were carefully selected for clinical homogeneity, with one difference: group I comprised patients who had no postoperative complications after free latissimus dorsi transfer. Group II included only patients with major postoperative complications after the procedure. All flaps in group II survived after successful surgical revision. The arteries, which nourished the lower leg, were visualized and documented by means of a duplex scanner in both groups. Three different time intervals were chosen for measurements of blood flow: 4 to 6 months (groups I.I and II.I), 4 to 6 years (groups I.II and II.II), and 8 to 10 years (groups I.III and II.III). Quantitative measurements of local flap perfusion in milliliters per minute per 100 g tissue were performed by means of the hydrogen clearance technique. In each patient, a total of nine measurements was performed in three phases: phase A, before closing the vascular pedicle by manual compression (n = 3); phase B, with a closed pedicle (n = 3); and phase C, after releasing the vascular pedicle from manual compression (n = 3). Each measurement took approximately 10 minutes. One hundred percent closure of each pedicle in phase B was confirmed by the duplex scanner. Furthermore, all patients were monitored both clinically and by means of the hydrogen clearance technique during phase B for adequate blood supply to the lower leg. Lower leg perfusion showed no statistical differences for phases A, B, and C in all groups of patients. In group I, no statistical differences in local flap perfusion were encountered for phases A and C. In phase B, however, a statistically significant (p < 0.01) complete extinction of local flap perfusion was registered in all patients of group I at the site of the flap's skin paddle. In group II, however, persistent flap perfusion was registered during phase B in up to 50 percent of cases in one subgroup (II.III). No statistically significant alterations of local blood flow were registered in the surrounding tissue of group II during phases A, B, and C. Patients with thrombosis of the venous anastomosis (n = 7) seemed to have the highest incidence of loss of autonomous blood supply through the vascular pedicle (5 out of 11 cases). No inconstant results were found during the repetitive measurements (n = 3) for each patient in each phase. After uncomplicated free tissue transfer, the flap's intact vascular pedicle seems to play an important role in permanent flap survival up to 10 years after the procedure. Postoperative complications after free tissue transfer with successful surgical revision, especially venous thrombosis of the vascular anastomosis, may lead to loss of vascular flap autonomy over time.

Adult↗
PubMed1999

Arterial crush injury causes decrease in tissue perfusion at the level of the microcirculation in skeletal muscle flap.

This study was designed to evaluate the effects of crush injuries to the feeding arteries of a muscle flap on microcirculatory haemodynamics. Eighteen male Sprague-Dawley rats were divided into three experimental groups for intravital microscopy of the cremaster muscle flap. Group 1 served as control. In group 2 the common iliac artery and in group 3 additionally the lower abdominal aorta was crushed with a Kocher clamp (17.4 N) over 5 min. Microcirculatory parameters (red blood cell velocity, vessel diameter, and capillary perfusion) were monitored before and 2 h after crush. In the one-level crush group, red blood cell velocities significantly decreased by 39.17% (P=0.046) in first order arterioles and by 32. 91% (P=0.0106) in second order arterioles. In capillary perfusion, a drop of 48.02% (P=0.0039) was noted. In the two-level crush group, red blood cell velocities significantly dropped over 32.06% (P=0. 0250) in first order arterioles, 35.91% (P=0.0065) in second order arterioles, and 45.69% (P=0.0782) in first order venules. Capillary perfusion was reduced by 20.16% (P=0.374). Arterial crush injuries as possible thrombogenic insults may result in a significant decrease in skeletal muscle perfusion although the blood supply through the crushed supplying vessel is maintained.

Animals↗
PubMed1999

Failure in developing a model for complete vascular thrombosis in the common iliac artery in the rat.

The purpose of this study was to develop a model for complete arterial thrombosis proximal to the rat cremaster flap for subsequent fibrinolytic studies at the microcirculatory level. We divided 20 male Sprague-Dawley rats into four experimental groups of five animals each. We assigned each group to an established thrombosis model using crush and standard microsurgical anastomosis, crush and intimal abrasion, inverted arterial suture, and intravascular silk sutures combined with microsurgical anastomosis at the common iliac artery. Vessel patency was examined using the milking test 30, 60, 90, and 120 min after the thrombogenic insults. The model of perpendicular silk sutures and anastomosis caused complete arterial thrombosis in one animal over 120 min. The other models failed in all animals. In conclusion, the thrombogenic models used in this study are not capable of creating a reliable complete arterial thrombosis in the common iliac artery of the rat.

Animals↗