A Platform for Testing the Biocompatibility of Implants: Silicone Induces a Proinflammatory Response in a 3D Skin Equivalent.

Biocompatibility testing of materials is carried out in 2D cell cultures or animal models despite serious limitations. 3D skin equivalents are advanced in vitro models for human skin. Silicone has been shown to be noncytotoxic but capable of eliciting an immune response. Our aim was to (1) establish a 3D skin equivalent to (2) assess the proinflammatory properties of silicone. We developed a coculture of keratinocytes and fibroblasts resulting in a 3D skin equivalent with an implant using samples from a breast implant. Samples with and without the silicone implant were studied histologically and immunohistochemically in comparison to native human skin samples. Cytotoxicity was assessed via LDH-assay, and cytokine response was assessed via ELISA. Histologically, our 3D skin equivalents had a four-layered epidermal and a dermal component. The presence of tight junctions was demonstrated in immunofluorescence. The only difference in 3D skin equivalents with implants was an epidermal thinning. Implanting the silicone samples did not cause more cell death, however, an inflammatory cytokine response was triggered. We were able to establish an organotypical 3D skin equivalent with an implant, which can be utilised for studies on biocompatibility of materials. This first integration of silicone into a 3D skin equivalent confirmed previous findings on silicone being non-cell-toxic but capable of exerting a proinflammatory effect.

Immunofluorescence analysis of sensory nerve endings in the periarticular tissue of the human elbow joint.

INTRODUCTION: To investigate the dynamic aspects of elbow stability, we aimed to analyze sensory nerve endings in the ligaments and the capsule of elbow joints. MATERIALS AND METHODS: The capsule with its anterior (AJC) and posterior (PJC) parts, the radial collateral ligament (RCL), the annular ligament (AL), and the ulnar collateral ligament with its posterior (PUCL), transverse (TUCL) and anterior parts (AUCL) were dissected from eleven human cadaver elbow joints. Sensory nerve endings were analyzed in two levels per specimen as total cell amount/ cm2 after immunofluorescence staining with low-affinity neurotrophin receptor p75, protein gene product 9.5, S-100 protein and 4',6-Diamidin-2-phenylindol, Carbonic anhydrase II and choline acetyltransferase on an Apotome microscope according to Freeman and Wyke's classification. RESULTS: Free nerve endings were the predominant mechanoreceptor in all seven structures followed by Ruffini, unclassifiable, Golgi-like, and Pacini corpuscles (p ≤ 0.00001, respectively). Free nerve endings were observed significant more often in the AJC than in the RCL (p < 0.00002). A higher density of Ruffini endings than Golgi-like endings was observed in the PJC (p = 0.004). The RCL contained significant more Ruffini endings than Pacini corpuscles (p = 0.004). Carbonic anhydrase II was significantly more frequently positively immunoreactive than choline acetyltransferase in all sensory nerve endings (p < 0.05). Sensory nerve endings were significant more often epifascicular distributed in all structures (p < 0.006, respectively) except for the AJC, which had a pronounced equal distribution (p < 0.00005). CONCLUSION: The high density of free nerve endings in the joint capsule indicates that it has pronounced nociceptive functions. Joint position sense is mainly detected by the RCL, AUCL, PUCL, and the PJC. Proprioceptive control of the elbow joint is mainly monitored by the joint capsule and the UCL, respectively. However, the extreme range of motion is primarily controlled by the RCL mediated by Golgi-like endings.

Development of a 3D-immunofluorescence analysis for sensory nerve endings in human ligaments.

BACKGROUND: The analysis of ligamentous mechanoreceptors is difficult due to a high amount of unclassifiable mechanoreceptors, which result from incomplete visualization through limited microscopic techniques. NEW METHOD: The method was developed using dorsal intercarpal ligaments and dorsal regions of the scapholunate interosseous ligament from human cadaver wrists. Consecutive 70 µm thick cryosections were stained with immunofluorescence markers for protein S100B, neurotrophin receptor p75 (p75), protein gene product 9.5 (PGP 9.5) and 4',6-diamidino-2-phenylindole (DAPI). 3D images of sensory nerve endings were obtained using a confocal laser scanning microscope. Experimental point spread functions (PSF) were used to deconvolve images. Sensory nerve endings were localised in each section plane and classified according to Freeman and Wyke. Finally, confocal data was visualized as 3D-images. RESULTS: The method produced excellent image quality, revealing detailed three-dimensional structures. The created 3D-model of sensory nerve endings could be analyzed in all three dimensions, augmenting visualization of the form and immunoreactive pattern of sensory nerve endings. Deconvolution with experimentally measured PSFs aided in enhancing image quality. COMPARISON WITH EXISTING METHODS: Using a triple immunofluorescent staining method allows to visualize the structure of sensory nerve endings more precisely than techniques with serial analysis of different monostaining of neural markers. Imaging in three dimensions enhances morphologic details, which are limited in 2D-microscopy. CONCLUSION: 3D-triple immunofluorescence produces high quality visualization of mechanoreceptors, thereby improving their analysis. As an elaborate technique, it is ideal for defined research questions concerning the microstructure of sensory nerve endings.

Closing the Gap: Bridging Peripheral Sensory Nerve Defects with a Chitosan-Based Conduit a Randomized Prospective Clinical Trial.

Introduction: If tensionless nerve coaptation is not possible, bridging the resulting peripheral nerve defect with an autologous nerve graft is still the current gold standard. The concept of conduits as an alternative with different materials and architectures, such as autologous vein conduits or bioartificial nerve conduits, could not replace the nerve graft until today. Chitosan, as a relatively new biomaterial, has recently demonstrated exceptional biocompatibility and material stability with neural lineage cells. The purpose of this prospective randomized clinical experiment was to determine the efficacy of chitosan-based nerve conduits in regenerating sensory nerves in the hand. Materials and methods: Forty-seven patients with peripheral nerve defects up to 26 mm distal to the carpal tunnel were randomized to receive either a chitosan conduit or an autologous nerve graft with the latter serving as the control group. Fifteen patients from the conduit group and seven patients from the control group were available for a 12-month follow-up examination. The primary outcome parameter was tactile gnosis measured with two-point discrimination. The secondary outcome parameters were Semmens Weinstein Monofilament Testing, self-assessed pain, and patient satisfaction. Results: Significant improvement (in static two-point discrimination) was observed six months after trauma (10.7 ± 1.2 mm; p < 0.05) for chitosan-based nerve conduits, but no further improvement was observed after 12 months of regeneration (10.9 ± 1.3 mm). After six months and twelve months, the autologous nerve graft demonstrated comparable results to the nerve conduit, with a static two-point discrimination of 11.0 ± 2.0 mm and 7.9 ± 1.1 mm. Semmes Weinstein Filament Testing in the nerve conduit group showed a continuous improvement over the regeneration period by reaching from 3.1 ± 0.3 after three months up to 3.7 ± 0.4 after twelve months. Autologous nerve grafts presented similar results: 3.3 ± 0.4 after three months and 3.7 ± 0.5 after twelve months. Patient satisfaction and self-reported pain levels were similar between the chitosan nerve conduit and nerve graft groups. One patient required revision surgery due to complications associated with the chitosan nerve tube. Conclusion: Chitosan-based nerve conduits are safe and suitable for bridging nerve lesions up to 26 mm in the hand. Tactile gnosis improved significantly during the early regeneration period, and functional outcomes were similar to those obtained with an autologous nerve graft. Thus, chitosan appears to be a sufficient substitute for autologous nerve grafts in the treatment of small nerve defects in the hand.

Comparative histomorphological analysis of elbow ligaments and capsule.

This study aimed to compare the histomorphology of the elbow capsule and its ligaments to gain a better understanding of the clinically relevant biomechanical stabilization. Eleven human elbows were dissected including the joint capsule with its anterior (AJC) and posterior (PJC) parts, the annular ligament (AL), the radial collateral ligament (RCL) and the ulnar collateral ligament with its anterior (AUCL), posterior (PUCL) and transverse (TUCL) parts. Hematoxylin-Eosin and Elastica van Gieson as conventional histology stainings were applied to determine collagenous and elastic fiber arrangements in transmission and polarization light microscopy. The radial collateral ligament and the anterior part of the ulnar collateral ligament showed significantly more densely packed parallel fiber arrangement than the anterior joint capsule, the posterior joint capsule, and the posterior part of the ulnar collateral ligament (p < 0.02, respectively). The PUCL had significantly more mixed tight and loose parallel arrangements than the PJC, the annular ligament, the RCL, the AUCL and the transverse part of the ulnar collateral ligamentp < 0.02, respectively), while the PJC showed significantly more interlaced mixed tight and loose fiber arrangement than the AL, the RCL and the AUCL (p < 0.003, respectively). The AJC had a significantly higher amount of elastic fibers as compared to the AL, the RCL, the AUCL and the TUCL in fascicular regions (p < 0.04, respectively), while the AUCL had significantly lesser elastic fibers than the AJC and the PJC (p < 0.004, respectively). The densely packed parallel fiber arrangement and few elastic fibers of the AUCL, RCL, and AL indicate a strong biomechanically stabilizing function. The fiber arrangement of the PUCL and the TUCL with few elastic fibers support the medial elbow stabilization. Crimping and elastic fibers provide the viscoelasticity of the joint capsule.

[Establishing a standardized diagnostic Procedure for sonographic Imaging and Evaluation of the scapholunate Ligament]. / Etablierung eines standardisierten Untersuchungsverfahrens zur sonographischen Darstellung und Beurteilung des skapholunären Bandes.

BACKGROUND: Ultrasound has not yet been established in the diagnostic workup of scapholunate ligament lesions. We aimed to develop a standardised examination procedure to visualise and evaluate the SL ligament. PATIENTS AND METHODS: Forty patients (70 hands) were examined prospectively with ultrasonography and the results were compared with arthroscopy and MRI findings. We studied the visibility of the SL ligament and the SL distance on side-to-side comparison and performed a method comparison between MRI/arthroscopy and ultrasound, testing for distinction and accordance. Cut-off values for the SL distance indicating a lesion were determined and all parameters were used for developing a score. RESULTS: An intact ligament appears as a hyperechogenic, fibrillary structure and shows discontinuity or a hypoechogenic space when injured. An intact ligament was visible dorsally in 89.6 % and palmarly in 83.3 %. The SL distance for an intact ligament was 5/2/5.1 mm for the dorsal/middle/palmar aspect (range 3.2-6.7/0.9-4/3.1-7.8 mm) and 6.4/3/6.3 mm (range 5-9.4/2-6.2/4-9.3 mm) for a lesion. The difference between the right and left hand with an intact ligament was a maximum of 2.1/1.1/1.8 mm, an average of 0.4/0.2/0.2 mm; in case of an injury, the maximum difference was 1.2/0.9/1.1 mm. Distance values for radial and ulnar deviation were physiological but partly unpredictable. The cut-off values determined for a lesion are 5.05 mm for the dorsal aspect (sensitivity/specificity 0.95/0.60), 1.95 mm for the middle (1/0.62) and 6.15 mm for the palmar aspect (0.55/0.85). The created sonographic SL ligament score has a high AUC (area under the curve) of 0.93, a sensitivity of 85 % and a specificity of 90 %. CONCLUSION: The parameters, especially when combined to a score, allow to state whether the SL ligament is intact or not. Ultrasound can, therefore, be recommended as a diagnostic and screening method for an SL ligament lesion und should be used as a routine tool. The criteria must be checked from a perspective with high case numbers.

Burn depth assessment using hyperspectral imaging in a prospective single center study.

BACKGROUND: The assessment of thermal burn depth remains challenging. Over the last decades, several optical systems were developed to determine burn depth. So far, only laser doppler imaging (LDI) has been shown to be reliable while others such as infrared thermography or spectrophotometric intracutaneous analysis have been less accurate. The aim of our study is to evaluate hyperspectral imaging (HSI) as a new optical device. METHODS: Patients suffering thermal trauma treated in a burn unit in Germany between November 2019 and September 2020 were included. Inclusion criteria were age ≥18 years, 2nd or 3rd degree thermal burns, written informed consent and presentation within 24 h after injury. Clinical assessment and hyperspectral imaging were performed 24, 48 and 72 h after the injury. Patients in whom secondary wound closure was complete within 21 days (group A) were compared to patients in whom secondary wound closure took more than 21 days or where skin grafting was indicated (group B). Demographic data and the primary parameters generated by HSI were documented. A Mann Whitney-U test was performed to compare the groups. A p-value below 0.05 was considered to be statistically significant. The data generated using HSI were combined to create the HSI burn index (BI). Using a logistic regression and receiver operating characteristics curve (ROC) sensitivity and specificity of the BI were calculated. The trial was officially registered on DRKS (registration number: DRKS00022843). RESULTS: Overall, 59 patients with burn wounds were eligible for inclusion. Ten patients were excluded because of a poor data quality. Group A comprised 36 patients with a mean age of 41.5 years and a mean burnt body surface area of 2.7%. In comparison, 13 patients were allocated to group B because of the need for a skin graft (n = 10) or protracted secondary wound closure lasting more than 21 days. The mean age of these patients was 46.8 years. They had a mean affected body surface area of 4.0%. 24, 48, and 72 h after trauma the BI was 1.0 ± 0.28, 1.2 ± 0.29 and 1.55 ± 0.27 in group A and 0.78 ± 0.14, 1.05 ± 0.23 and 1.23 ± 0.27 in group B. At every time point significant differences were demonstrated between the groups. At 24 h, ROC analysis demonstrated BI threshold of 0.95 (sensitivity 0.61/specificity 1.0), on the second day of 1.17 (sensitivity 0.51/specificity 0.81) and on the third day of 1.27 (sensitivity 0.92/specificity 0.71). CONCLUSION: Changes in microcirculation within the first 72 h after thermal trauma were reflected by an increasing BI in both groups. After 72 h, the BI is able to predict the need for a skin graft with a sensitivity of 92% and a specificity of 71%.

Stevens-Johnson syndrome and toxic epidermal necrolysis: a systematic review and meta-analysis.

OBJECTIVE: Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN) are rare and severe skin and mucosal reactions that are associated with high mortality. Despite the severity, an evidence-based treatment protocol for SJS/TEN is still lacking. METHOD: In this systematic review and meta-analysis, the PubMed database was searched using the following terms: [Stevens-Johnson syndrome] OR [toxic epidermal necrolysis] AND [therapy] OR [treatment] over a 20-year period (1999-2019) in the German and English language. All clinical studies reporting on the treatment of SJS/TEN were included, and epidemiological and diagnostic aspects of treatment were analysed. A meta-analysis was conducted on all comparative clinical studies that met the inclusion criteria. RESULTS: A total of 88 studies met the inclusion criteria, reporting outcomes in 2647 patients. Treatment was either supportive or used systemic corticosteroid, intravenous immunoglobulin, plasmapheresis, cyclosporine, thalidomide or cyclophosphamide therapy. The meta-analysis included 16 (18%) studies, reporting outcomes in 976 (37%) patients. Systemic glucocorticoids showed a survival benefit for SJS/TEN patients in all analyses compared with other forms of treatment. Cyclosporine treatment also showed promising results, despite being used in a small cohort of patients. No beneficial effects on mortality could be demonstrated for intravenous immunoglobulins. CONCLUSION: Glucocorticoids and cyclosporine may be tentatively recommended as the most promising immunomodulatory therapies for SJS/TEN, but these results should be investigated in future prospective controlled trials.

Stevens-Johnson syndrome and toxic epidermal necrolysis: a 10-year experience in a burns unit.

OBJECTIVE: Stevens-Johnson syndrome (SJS) and its more severe counterpart, toxic epidermal necrolysis (TEN), are skin hypersensitivity reactions defined by epidermal blistering and necrosis. The exact pathophysiology of SJS/TEN is yet to be deciphered, but a number of risk factors have been identified including adverse drug reactions. The diagnosis of SJS/TEN is made on a clinical basis, and treatment consists of supportive care and occasionally immunosuppressants, such as cyclosporin, high-dose intravenous immunoglobulins and/or corticosteroids. Mortality rates can reach 20-25% in adults but are reduced with early intervention. To identify optimal treatment regimens, to better understand the patient cohort affected, and to help identify key risk factors for mortality, we report our experience with the treatment and management of SJS/TEN patients. METHODS: A retrospective review of consecutive patients with SJS and/or TEN admitted to a single burns centre in Germany, between 2008 and 2018, was conducted. The primary outcomes of demographics, clinical course, treatment and patient-reported outcomes were recorded and compared with a control group of patients with burns without a diagnosis of SJS/TEN. RESULTS: A total of 23 patients with SJS/TEN met the inclusion criteria: 17 (74%) with TEN; four (17%) with SJS/TEN overlap; and two (9%) with SJS. Of the patients, 14 (61%) were female and nine (39%) were male. Patient age ranged from 32-78 years (mean: 52 years). A matched cohort of 23 patients with burns served as the control group. All patients received standard of care with a multidisciplinary team. Compared with the control group, SJS/TEN patients had higher mortality rates (n=6, 26% versus n=8, 35%, respectively). The average age of death was 69 years in SJS/TEN patients versus 63 years in control group patients. Age and SCORTEN scores were significant predictors of mortality. CONCLUSIONS: SJS and TEN are rare but extreme reactions of the skin and mucosa, associated with high disease mortality rates. This 10-year single-centre retrospective review contributes to the bank of information for reviews evaluating the management of SJS/TEN patients.

3D-perfusion analysis of burn wounds using hyperspectral imaging.

BACKGROUND: Determination of the depth of burn wounds is still a challenge in clinical practise and fundamental for an optimal treatment. Hyperspectral imaging (HSI) has a high potential to be established as a new contact-free measuring method in medicine. From hyperspectral spectra 3D-perfusion parameters can be estimated and the microcirculatory of burn wounds over the first 72h after thermal injury can be objectively described. METHODS: We used a hyperspectral imaging camera and extended data processing methods to calculate 3D-perfusion parameters of burn wounds from adult patients. The data processing results in the estimation of perfusion parameters like volume fraction and oxygenation of haemoglobin for 6 different layers of the injured skin. The parameters are presented as depth profiles. We analyzed and compared measurements of wounds of different degrees of damage and present the methodology and preliminary results. RESULTS: The depth profiles of the perfusion parameters show characteristic features and differences depending on the degree of damage. With Hyperspectral Imaging and the advanced data processing the perfusion characteristics of burn wounds can be visualized in more detail. Based on the analysis of this perfusion characteristics, a new and better reliable classification of burn degrees can be developed supporting the surgeon in the early selection of the optimal treatment.

[Hyperspectral imaging for postoperative flap monitoring of pedicled flaps]. / Hyperspektralimaging zum postoperativen Lappenmonitoring von lokoregionären Lappenplastiken.

BACKGROUND: Since pedicle flaps were first described by the Indian physician Sushruta Samhita in the 6th century B. C., they have become an integral part of reconstructive surgery. As more and more research has been conducted into the underlying physical principles, flap monitoring has developed steadily in the last few decades. Hyperspectral Imaging (HSI) is a new quantitative measuring method for assessing the perfusion of the underlying tissue. OBJECTIVE: This study aims to evaluate HSI as a monitoring method for pedicle flaps. PATIENTS AND METHODS: In 16 patients who had undergone reconstructive surgery, oxygen saturation, haemoglobin and water concentration of the locoregional flap, necrotic flap areas as well as intact skin were measured on postoperative days 1 to 7. Subsequently, the data were statistically described and graphically illustrated. RESULTS: HSI revealed increased haemoglobin concentration and decreased oxygen and water concentration in necrotic flap areas compared with the monitor island and healthy skin. The distribution of the values collected from the vital skin areas and the monitor island was almost identical. CONCLUSION: HSI allows for safe, immediate, non-contact measurement of tissue perfusion of transferred tissue areas in patients after pedicle flap surgery. The use of HSI may improve postoperative flap monitoring.

Structural topography of the interosseous membrane of the human forearm.

The aim of this study was to evaluate the morphology of the six different parts of the interosseous membrane (IOM) in 11 human cadaver forearms, including the distal oblique bundle (DOB), the distal accessory band (DAB), the central band (CB), the proximal accessory band (PAB), the dorsal oblique accessory cord (DOAC), and the proximal oblique cord (POC). Hematoxylin-eosin and Elastica van Gieson stained slices were used to investigate the tissue morphology. The DOB and DOAC were absent in one IOM and the POB in two IOMs, respectively. The CB and DAB were longer than all other structures except for each other. The DOAC was longer than the DOB. The DAB, CB, and PAB, were broader than the DOB, DOAC, and POC. No significant differences were observed regarding structure thickness. All structures were found to consist of densely packed parallel collagen fiber arrangement. The DOB and POC had a higher amount of elastic fibers in the fascicular collagen tissue than the other structures. Elastic fibers were more often equally distributed throughout the structures than condensed epifascicular or at the insertion into bone. The tight parallel collagen composition within the different structures reflects the central stabilizing role of the IOM in the forearm. The higher amount of elastic fibers within the DOB and POC can be attributed to their location close to the distal and proximal radioulnar joints, respectively. Here elastic fibers allow adaption to forearm rotation, whereas the structures of the central part of IOM have less elasticity reflecting the predominant stabilizing function.

Burns: modified metabolism and the nuances of nutrition therapy.

OBJECTIVE: To review the effects of burn injury on nutritional requirements and how this can best be supported in a healthcare setting. METHOD: A literature search for articles discussing nutrition and/or metabolism following burn injury was carried out. PubMed, Embase and Web of Science databases were searched using the key search terms 'nutrition' OR 'metabolism' AND 'burn injury' OR 'burns'. There was no limitation on the year of publication. RESULTS: A total of nine articles met the inclusion criteria, the contents of which are discussed in this manuscript. CONCLUSION: Thermal injury elicits the greatest metabolic response, among all traumatic events, in critically ill patients. In order to ensure burn patients can meet the demands of their increased metabolic rate and energy expenditure, adequate nutritional support is essential. Burn injury results in a unique pathophysiology, involving alterations in endocrine, inflammatory, metabolic and immune pathways and nutritional support needed during the inpatient stay varies depending on burn severity and idiosyncratic patient physiologic parameters.

Mechanical ventilation as a surrogate for diagnosing the onset of abdominal compartment syndrome (ACS) in severely burned patients (TIRIFIC-study Part II).

Intra-abdominal compartment syndrome (ACS) is a devastating complication in burn patients with a high mortality. Apart from high-volume resuscitation as known risk factor, also mechanical ventilation seems to influence the development of ACS. The TIRIFIC trial is a retrospective, matched-pair analysis. Thirty-eight burn patients with ACS were matched for burned total body surface area (TBSA), age and mechanical ventilation (MV). In contrast to the already published part I addressing fluid resuscitation as a risk factor, the parameters analyzed in part II were maximum and average PEEP and peak pressure levels as well as serum lactate levels and prokinetic therapy. For subgroup-analysis the ACS-group was split up into an early-onset and late-onset ACS-group according to the median time between burn trauma and ACS. The groups were analyzed with a two-sided Mann-Whitney-U-test with significance set at p < 0.05. In the ACS-group all ventilation pressures (maximum and average PEEP and peak pressure levels) were significantly increased compared to control. The subgroup-analysis showed significantly increased maximum PEEP and peak pressure levels in early- and late-onset ACS-groups versus control. However, the average ventilation pressure levels were only increased in the early-onset ACS-group (average PEEP p = 0.0069; average peak pressure p = 0.05). The TIRIFIC trial showed significantly increased ventilation pressures in the ACS group in general as a surrogate parameter to support early diagnostics. Especially, maximum PEEP levels and peak pressures are significantly increased in both, early- and late-onset ACS. As an addition to the actual WSACS guidelines we suggest IAP measurement in mechanically ventilated burn patients if ventilating pressures are rising continuously without a clear pulmonary or otherwise identifiable reason.

Molecular Mechanisms of Hair Growth and Regeneration: Current Understanding and Novel Paradigms.

Hair is a defining feature of mammals and has critical functions, including protection, production of sebum, apocrine sweat and pheromones, social and sexual interactions, thermoregulation, and provision of stem cells for skin homeostasis, regeneration, and repair. The hair follicle (HF) is considered a "mini-organ," consisting of intricate and well-organized structures which originate from HF stem and progenitor cells. Dermal papilla cells are the main components of the mesenchymal compartments in the hair bulb and are instrumental in generating signals to regulate the behavior of neighboring epithelial cells during the hair cycle. Mesenchymal-epithelial interactions within the dermal papilla niche drive HF embryonic development as well as the postnatal hair growth and regeneration cycle. This review summarizes the current understanding of HF development, repair, and regeneration, with special focus on cell signaling pathways governing these processes. In particular, we discuss emerging paradigms of molecular signaling governing the dermal papilla-epithelial cellular interactions during hair growth and maintenance and the recent progress made towards tissue engineering of human hair follicles.

Evaluation of proprioception in denervated and healthy wrist joints.

We recruited 25 patients after complete wrist denervation and 60 healthy adults to investigate conscious and unconscious proprioception of the wrist. Ipsi- and contralateral joint-position sense, force sense, and wrist reflexes were measured. The latter were triggered by a trapdoor, recording electromyographic signals from the extensor carpi radialis brevis, extensor carpi ulnaris, flexor carpi radialis, and flexor carpi ulnaris muscles. No significant differences were found for joint position sense, force sense, and wrist reflexes between both groups, except for reflex time of the flexor carpi ulnaris after denervation of the left wrist as compared with the left flexor carpi ulnaris in controls or in right operated wrists. At a mean follow-up of 32 months (range 8 to 133), we found no proprioceptive deficit of the conscious proprioceptive qualities of joint position sense, force sense, and the unconscious proprioceptive neuromuscular control of wrist reflex time for most muscles after complete wrist denervation. We conclude from this study that complete wrist denervation does not affect the proprioceptive senses of joint position, force sense, and reflex time of the wrist.

[Microsurgical soft tissue reconstruction in lower extremity osteitis]. / Mikrochirurgische Weichteilrekonstruktion bei Osteitis der unteren Extremität.

BACKGROUND: The aim of this study was to analyse retrospectively the pre- and intraoperative factors influencing flap loss after free flap coverage of septic skin defects caused by osteitis of the lower extremity with an anterolateral thigh flap (ALT) or latissimus dorsi (LD) flap. MATERIAL AND METHODS: Twenty-seven patients were surgically treated with LD flap coverage and 45 patients with ALT flap coverage between 2004 and 2013. Their anthropometric, pre- and intraoperative parameters were investigated retrospectively. RESULTS: Flap survival was 81.5 % for LD flaps and 82.2 % for ALT flaps. Major complications led to a significantly higher flap loss both in LD (p = 0.01) and ALT flaps (p < 0.0001). Furthermore, there was a significant increase in flap loss with pre-existing diabetes mellitus in the LD group (p = 0.001) and with acute osteomyelitis being the underlying cause of the soft tissue defect in the ALT group (p = 0.034). Regardless of the flap's postoperative success, LD flaps were used for significantly larger soft tissue defects to be reconstructed (p = 0.001), with the duration of surgery (p < 0.0001) and cold ischaemia time (p = 0.001) being significantly longer compared with ALT flaps. CONCLUSIONS: The success of microsurgical flap reconstruction in lower extremities after osteitis was influenced by a low number of cases with preexisting diabetes mellitus, causative acute osteomyelitis, and major complications. Therefore, optimal management of both parameters and precise microsurgical anastomosis are prerequisites for successful plastic reconstruction of soft tissue defects.

Immunofluorescence analysis of sensory nerve endings in the interosseous membrane of the forearm.

The human interosseous membrane (IOM) is a fundamental stabilizer during forearm rotation. To investigate the dynamic aspects of forearm stability, we analyzed sensory nerve endings in the IOM. The distal oblique bundle (DOB), the distal accessory band (DAB), the central band (CB), the proximal accessory band (PAB), the dorsal oblique accessory cord (DOAC) and the proximal oblique cord (POC) were dissected from 11 human cadaver forearms. Sensory nerve endings were analyzed at two levels per specimen as total cell amount/mm2 after immunofluorescence staining with low-affinity neurotrophin receptor p75, protein gene product 9.5, S-100 protein and 4',6-diamidino-2-phenylindole on an Apotome microscope, according to Freeman and Wyke's classification. Sensory nerve endings were significantly more commonly found to be equally distributed throughout the structures, rather than being epifascicular, interstitial, or close to the insertion into bone (P ≤ 0.001, respectively). Free nerve endings were the predominant mechanoreceptor in all six structures, with highest density in the DOB, followed by the POC (P ≤ 0.0001, respectively). The DOB had the highest density of Pacini corpuscles. The DOAC and CB had the lowest amounts of sensory innervation. The high density of sensory corpuscles in the DOB, PAB and POC indicate that proprioceptive control of the compressive and directional muscular forces acting on the distal and proximal radioulnar joints is monitored by the DOB, PAB and POC, respectively, due to their closed proximity to both joints, whereas the central parts of the IOM act as structures of passive restraint.

Extended Perfusion Parameter Estimation from Hyperspectral Imaging Data for Bedside Diagnostic in Medicine.

Background: Hyperspectral Imaging (HSI) has a strong potential to be established as a new contact-free measuring method in medicine. Hyperspectral cameras and data processing have to fulfill requirements concerning practicability and validity to be integrated in clinical routine processes. Methods: Calculating physiological parameters which are of significant clinical value from recorded remission spectra is a complex challenge. We present a data processing method for HSI remission spectra based on a five-layer model of perfused tissue that generates perfusion parameters for every layer and presents them as depth profiles. The modeling of the radiation transport and the solution of the inverse problem are based on familiar approximations, but use partially heuristic methods for efficiency and to fulfill practical clinical requirements. Results: The parameter determination process is consistent, as the measured spectrum is practically completely reproducible by the modeling sequence; in other words, the whole spectral information is transformed into model parameters which are easily accessible for physiological interpretation. The method is flexible enough to be applicable on a wide spectrum of skin and wounds. Examples of advanced procedures utilizing extended perfusion representation in clinical application areas (flap control, burn diagnosis) are presented.