A self-made, low-cost infrared system for evaluating the sciatic functional index in mice

The sciatic functional index（SFI） is a popular parameter for peripheral nerve evaluation that relies on footprints obtained with ink and paper. Drawbacks include smearing artefacts and a lack of dynamic information during measurement. Modern applications use digitized systems that can deliver results with less analytical effort and fewer mice. However, the systems are expensive（€40,000）. This study aimed to evaluate the applicability and precision of a self-made, low-cost infrared system for evaluating SFI in mice. Mice were subjected to unilateral sciatic nerve crush injury（crush group; n = 7） and sham operation（sham group; n = 4）. They were evaluated on the day before surgery, the 2nd, 4th and 6th days after injury, and then every day up to the 23rd day after injury. We compared two SFI evaluation methods, i.e., conventional inkand-paper SFI（C-SFI） and our infrared system（I-SFI）. Our apparatus visualized footprints with totally internally reflected infrared light（950 nm） and a camera that can only detect this wavelength. Additionally we performed an analysis with the ladder beam walking test（LBWT） as a reference test. I-SFI assessment reduced the standard deviation by about 33 percent, from 11.6 to 7.8, and cut the variance around the baseline to 21 percent. The system thus requires fewer measurement repetitions and fewer animals, and cuts the cost of keeping the animals. The apparatus cost €321 to build. Our results show that the process of obtaining the SFI can be made more precise via digitization with a self-made, low-cost infrared system.

N-Propionylmannosamine stimulates axonal elongation in a murine model of sciatic nerve injury

Increasing evidence indicates that sialic acid plays an important role during nerve regeneration. Sialic acids can be modified in vitro as well as in vivo using metabolic oligosaccharide engineering of the N-awl side chain. N-Propionylmannosamine （ManNProp） increases neurite outgrowth and accelerates the reestablishment of functional synapses in vitro. We investigated the influence of systemic ManNProp application using a specific in vivo mouse model. Using mice expressing axonal fluorescent proteins, we quantified the extension of regenerating axons, the number of regenerating axons, the number of arborising axons and the number of branches per axon 5 days after injury. Sciatic nerves from non-expressing mice were grafted into those expressing yellow fluorescent protein. We began a twice-daily intraperitoneal application of either peracetylated ManNProp （200 mg/kg） or saline solution 5 days before injury, and continued it until nerve harvest （5 days after transection）. ManNProp significantly increased the mean distance of axonal regeneration （2.49 mm vs. 1.53 mm; P 〈 0.005） and the number of arborizing axons （21% vs. 16%; P = 0.008） 5 days after sciatic nerve grafting. ManNProp did not affect the number of regenerating axons or the number of branches per arborizing axon. The biochemical glycoengineering of the N-acyl side chain of sialic acid might be a promising approach for improving peripheral nerve regeneration.

Fibrin glue repair leads to enhanced axonal elongation during early peripheral nerve regeneration in an in vivo mouse model

Microsurgical suturing is the gold standard of nerve coaptation. Although literature on the usefulness of fibrin glue as an alternative is becoming increasingly available, it remains contradictory. Furthermore, no data exist on how both repair methods might influence the morphological aspects（arborization; branching） of early peripheral nerve regeneration. We used the sciatic nerve transplantation model in thy-1 yellow fluorescent protein mice（YFP; n = 10）. Pieces of nerve（1cm） were grafted from YFP-negative mice（n = 10） into those expressing YFP. We performed microsuture coaptations on one side and used fibrin glue for repair on the contralateral side. Seven days after grafting, the regeneration distance, the percentage of regenerating and arborizing axons, the number of branches per axon, the coaptation failure rate, the gap size at the repair site and the time needed for surgical repair were all investigated. Fibrin glue repair resulted in regenerating axons travelling further into the distal nerve. It also increased the percentage of arborizing axons. No coaptation failure was detected. Gap sizes were comparable in both groups. Fibrin glue significantly reduced surgical repair time. The increase in regeneration distance, even after the short period of time, is in line with the results of others that showed faster axonal regeneration after fibrin glue repair. The increase in arborizing axons could be another explanation for better functional and electrophysiological results after fibrin glue repair. Fibrin glue nerve coaptation seems to be a promising alternative to microsuture repair.

N-Propionylmannosamine:using biochemical glycoengineering to promote peripheral nerve regeneration

The peripheral nervous system,in contrast to the central nervous system,is capable of spontaneous regeneration.However,nerve reconstruction in the peripheral nervous system remains a major challenge,as the functional outcomes following nerve repair are variable.

The Preauricular Sinus:A Novel Approach for Complete Bilateral Excision via a Modified Face-Lift Incision

Objectives/Hypothesis: To present a novel technique based on the combination of aesthetic and reconstructive techniques for the radical and safe excision of preauricular sinus along with minimal cosmetic impairing. Study Design: Case report, description of surgical method and brief overview of the literature. Methods: In a patient with bilateral preauricular sinus, we used a modified face-lift incision and SMAS-fixation instead of solely excising the sinus with skin ellipse. Results: Total removal of the bilateral fistulous systems could be achieved, along with a very aesthetically pleasing result. Conclusions: The surgical approach shown here allows a radical excision with only minimal aesthetic impairment using a shortened facelift-incision and SMAS-fixation.