Patrick Jaminet

Evaluation of sensory recovery after reconstruction of digital nerves of the hand using muscle-in-vein conduits in comparison to nerve suture or nerve autografting

Muscle‐in‐vein conduits are a good alternative solution to nerve autografts for bridging peripheral nerve defects since enough graft material is available and no loss of sensation at the harvesting area is expected. The purpose of this study was to compare regeneration results after digital nerve reconstruction with muscle‐in‐vein conduits, nerve autografts, or direct suture.

An improved electrophysiological method to study peripheral nerve regeneration in rats.

After restitution of motor function the grasping test alone is insufficient to figure out any further differences of axonal nerve regeneration of the median nerve in rats. To avoid this problem we developed a standardized electrophysiologic method for testing median nerve regeneration. Threshold, latency, compound muscle action potentials (CMAP) and velocity of neuromuscular transduction were recorded in 54 rats 20 weeks post-operatively. Animals of group 1 served as control group, no transection of the median nerve was carried out. Animals of groups 2 and 3 underwent either primary nerve coaptation or autologous nerve grafting after transection of the median nerve. To ensure validity of the method additional correlation between all parameters was investigated. Reliable electrophysiological results were observed in all animals. As expected, group 1 animals showed lowest threshold and latency and highest CMAP levels. Transection of the median nerve and additional nerve repair leads to significant increase of threshold and latency as well as reduction of CMAP. Furthermore, animals of group 3 showed higher levels for threshold and latency and reduced CMAP levels compared with animals of group 2. The grasping test alone could not demonstrate these slight differences 20 weeks post-operatively. Additionally, we observed strong correlations between threshold, latency and CMAP using the Spearman correlation ranking. We describe the usage of motor neurography as a reproducible and valid tool which should be mandatory for detailed analysis of regeneration in the rat median nerve model.

Fibulo-scapho-lunate arthrodesis after resection of the distal radius for giant-cell tumor of the bone

Giant‐cell tumors of the distal radius are rare. They have a high‐risk of local recurrence and a risk of pulmonary metastasis. Curettage alone or combined with adjunctive agents is often associated with local recurrence.

Development of an animal frostbite injury model using the Goettingen-Minipig

BACKGROUND A standardized reproducible animal model is desirable to gain a better understanding in the pathophysiology of frostbite injury and to develop novel therapies. Little has been studied about frostbite injury models. The depth and extent were not always being controllable and consistent. Therefore, we developed a frostbite injury model using the Göttingen Minipigs. METHODS 42 frostbite injuries were inflicted on the abdomen of seven minipigs using an aluminium bar (300g, circular with a radius of 1cm) frozen with liquid nitrogen to -196°C. The bar was applied for 1, 3, 6, 12, 30 and 60s. Five hours after injury biopsies were performed and evaluated by the presence of denatured collagen, blood vessels, follicular epithelial cells and mesenchymal cells. RESULTS A large spectrum of frostbite injuries was obtained ranging from superficial, superficial partial, deep partial to full thickness. The depth of injury in the sets of frostbites was highly consistent (Pearson correlation ranged from r=0.89 to 0.94). CONCLUSION We described a simple, inexpensive and safe swine frostbite model. The accurate reproducibility of the depth of the frostbite injuries allows researchers to accurately plan frostbite studies.

Reimbursement of burns by DRG in four European countries: An analysis

PURPOSE To analyze the German, Austrian, Italian and Spanish Diagnosis-Related Group (DRG)-systems regarding burns. METHODS We analyzed 78 cases of inpatients with burns which were processed by national DRG-groupers. DRGs were linked to thresholds concerning length of stay as well as reimbursement tables of the respective countries. MAIN FINDINGS Fifty-one % of cases showed higher reimbursement in Germany compared to Austria, 55% compared to Italy and 67% as against Spain. Total proceeds are highest in Austria with 1,577,000 €, followed by Italy with 1,569,000 €, Germany with 1,502,000 € and Spain with 902,596 €. No correlation was found between macroeconomic key figures and our data. CONCLUSIONS International comparison of reimbursement of burns by DRG could be a useful instrument for benchmarking while not depending solely on political decisions or country-specific cost data. For better comparability, hospital indices based on healthcare baskets should be discussed.

A quantitative analysis of microcirculation in sore-prone pressure areas on conventional and pressure relief hospital mattresses using laser Doppler flowmetry and tissue spectrophotometry

BACKGROUND Pressure ulcers are associated with severe impairment for the patients and high economic load. With this study we wanted to gain more insight to the skin perfusion dynamics due to external loading. Furthermore, we evaluated the effect of different types of pressure relief mattresses. METHODS A total of 25 healthy volunteers were enrolled in the study. Perfusion dynamics of the sacral and the heel area were assessed using the O2C-device, which combines a laser light, to determine blood flow, and white light to determine the relative amount of hemoglobin. Three mattresses were evaluated compared to a hard surface: a standard hospital foam mattress bed, a visco-elastic foam mattress, and an air-fluidized bed. RESULTS In the heel area, only the air-fluidized bed was able to maintain the blood circulation (mean blood flow of 13.6 ± 6 versus 3.9 ± 3 AU and mean relative amount of hemoglobin of 44.0 ± 14 versus 32.7 ± 12 AU.) In the sacral area, all used mattresses revealed an improvement of blood circulation compared to the hard surface. CONCLUSION The results of this study form a more precise pattern of perfusion changes due to external loading on various pressure relief mattresses. This knowledge may reduce the incidence of pressure ulcers and may be an influencing factor in pressure relief mattress selection.

A Postoperative Analysis of Perfusion Dynamics in Deep Inferior Epigastric Perforator Flap Breast Reconstruction A Noninvasive Quantitative Measurement of Flap Oxygen Saturation and Blood Flow

Background The blood supply of microvascular free flaps is rated as very critical, particularly in the first postoperative days. Only a timely recognition of a complication and its treatment can ensure the survival of the flap. To quantify the postoperative perfusion dynamics, we measured the oxygen supply and blood flow of the deep inferior epigastric perforator (DIEP) flaps. Method A total of 23 patients undergoing DIEP flap breast reconstruction were involved in this study. Noninvasive measurements were performed with the O2C-device, which combines the determination of hemoglobin oxygenation and blood flow using white light and laser light. The first measurement was performed immediately after the flap anastomosis. Further measurements were carried out on the first, third, fifth, and seventh postoperative days. Results The preoperative value represents our baseline. With the exception of the third day, all postoperative measurements were above the baseline. On the third postoperative day, there was a decrease in the cutaneous oxygen saturation of 22% and a decrease in blood flow of 18% on average, regardless of the individual fluctuations of patient’s blood pressure. Conclusions The postoperative perfusion characteristics of the DIEP flap showed a critical drop in the cutaneous oxygen supply and blood flow on the third postoperative day. This represents a potential risk and should be considered in the postoperative management of the DIEP flap.

The Effect of Repetitive Intraperitoneal Anesthesia by Application of Fentanyl-Medetomidine and Midazolam in Laboratory Rats

ABSTRACT Background: Literature reviews show numerous options for anesthesia in the small laboratory animals. Many methods are associated with complications, such as high technical effort, difficult monitoring, respiratory and cardiovascular depression, and prolonged sedation. In the present study, we report first time results after repeated use of an intraperitoneal combined anesthesia with a high tolerability. Methods: Three hundred and seventy-four anesthesias were performed on 38 adult male lewis rats (280–460g). Each animal was anesthetized repeatedly over a period of three months, using an intraperitoneal combination of Fentanyl-Medetomidine and Midazolam (FMM). The time required for the animals to lose ear pinch response and the ability to perform a righting and pedal withdrawal reflex was measured. For evaluation of the clinical state, a four-point vitality scale was developed. The anesthesia was antagonized with Naloxone, Flumazenil, and Atipamezole (s.c.). Results: The animals lost all three reflex responses within 5 (± 2.4) min of injection. Without antagonism of anesthesia, the ear pinch response returned on average within 125 (± 21.5) min. After antagonism of anesthesia, the rats needed 5 (± 2.9) min to regain all three reflex responses. No significant differences of vitality-index were measured after repeated use of FMM during the investigation period. Conclusions: A repeatable and secure anesthesia is indispensable for any experimental studies that require multiple anesthesia of a single animal. Intraperitoneal combination of FMM provides an adequate procedure to induce a well tolerable, repeatable state of anesthesia, which conforms to all the necessary requirements for laboratory rats.

Nervenrekonstruktion und Nervenersatzoperationen

The surgical treatment of peripheral nerve injuries is still a challenging and highly demanding procedure. Past results have been improved upon by different advances in microsurgical techniques and algorithms. Nevertheless, results are not always satisfying, making secondary procedures necessary. Thus, these secondary procedures such as tendon transfers and arthrodesis of different joints must be taken into account during reconstructive planning. This review gives an overview of peripheral nerve reconstruction (nerve grafting, nerve repair) and the pertinent secondary procedures.ZusammenfassungDie Versorgung von Nervenverletzungen und Nervendefekten stellt eine anspruchsvolle chirurgische Maßnahme dar. Verschiedene Techniken und Algorithmen haben in den vergangenen Jahren zu einer Verbesserung der chirurgischen Ergebnisse geführt. Trotz dieser Verfahren kommt es allerdings immer wieder zu einer Persistenz von Ausfällen und Lähmungserscheinungen. Daher ist es unabdingbar, dass der rekonstruktive Plan des Chirurgen auch so genannte Sekundär- oder Palliativmaßnahmen berücksichtigt, die sekundär zum Einsatz kommen können. Der vorliegende Beitrag gibt eine kurze Übersicht über die Versorgung peripherer Nervenverletzungen, die Nerventransplantation und verschiedene palliative Maßnahmen (Arthrodesen, motorische Ersatzoperationen usw.), die sekundär eingesetzt werden können.AbstractThe surgical treatment of peripheral nerve injuries is still a challenging and highly demanding procedure. Past results have been improved upon by different advances in microsurgical techniques and algorithms. Nevertheless, results are not always satisfying, making secondary procedures necessary. Thus, these secondary procedures such as tendon transfers and arthrodesis of different joints must be taken into account during reconstructive planning. This review gives an overview of peripheral nerve reconstruction (nerve grafting, nerve repair) and the pertinent secondary procedures.

Assessment of microcirculatory changes of cold contact injuries in a swine model using laser Doppler flowmetry and tissue spectrophotometry

BACKGROUND Until now, the exact pathophysiology of frostbite injuries is poorly understood. The aim of the study is to evaluate the perfusion changes of frostbite injuries to get a better understanding of the exact mechanism underlying the resulting tissue damage. Particular attention has been given to the differentiation of changes between the various injury depths. METHODS Cold contact injury ranging from superficial, superficial-partial, deep-partial to full thickness were generated using seven goettingen minipigs. The perfusion dynamics were assessed before and 3 h after the injuries were inflicted using the O2C-device, which combines a laser light, to determine blood flow, and white light to determine hemoglobin oxygenation and relative amount of hemoglobin. A total of 42 cold contact injuries were inflicted and 84 measurements were carried out. RESULTS In superficial and superficial partial injuries there was an increase in the blood flow (mean, 20 ± 2.4%, 15 ± 5.1%, respectively) and in the relative amount of hemoglobin (mean, 29 ± 9.1%, 28 ± 7.2%, respectively), whereas the hemoglobin oxygenation did not alter (mean, -0.15 ± 2.4%, -0.8 ± 3.1%, respectively). In deep partial injuries there was a decrease in the blood flow (mean range, -4 ± 2.1 to -17 ± 4.7%) and an increase in the relative amount of hemoglobin (mean range, 79 ± 17.2 to 93 ± 17.7%), whereas the hemoglobin oxygenation did not alter (mean range, -0.7 ± 3.1 to -2.9 ± 3.3%). In full thickness injuries there was a drop in the blood flow (mean range, -24 ± 7.6 to -27 ± 11.8%) and in the hemoglobin oxygenation (mean range, -16 ± 3.5 to -19 ± 2.5%) and an increase in the relative amount of hemoglobin (mean range, +126 ± 19.8 to 145 ± 10.9%). CONCLUSION The results of this study form a more precise pattern of cold contact injury perfusion changes, which can be a valuable tool to assess the degree of cold contact injury and furthermore the efficacy of novel diagnostic aids, therapeutics and treatment modalities.