An overture to basic science aspects of nerve injuries

Scar Tissue Causing Saphenous Nerve Entrapment: Percutaneous Scar Release and Fat Grafting

Painful neuropathies can be caused by nerve compression or neuromas. Nerve compressions can arise from scar adhesions causing painful posttraumatic entrapment of nerve branches via fibrosis. The classical treatment methods include neurolysis and nerve transposition. In this case, we present the treatment of recurrent scar entrapment of the saphenous nerve with percutaneous neurolysis and lipofilling in a patient who had previously undergone an open neurolysis procedure. Resolution of the condition without any complications was noted during the 2-month clinical follow-up. Percutaneous neurolysis and lipofilling are shown to be safe and reproducible methods for the treatment of neuropathic compressive scars.

Alignment of the Fibrin Network Within an Autologous Plasma Clot

Autologous plasma clots with longitudinally aligned fibrin fibers could serve as a scaffold for longitudinal axonal regrowth in cases of traumatic peripheral nerve injuries. Three different techniques for assembling longitudinally oriented fibrin fibers during the fibrin polymerization process were investigated as follows: fiber alignment was induced by the application of either a magnetic field or-as a novel approach-electric field or by the induction of orientated flow. Fiber alignment was characterized by scanning electron microscopy analysis followed by image processing using fast Fourier transformation (FFT). Besides FFT output images, area xmin to xmax, as well as full width at half maximum (FWHM) of the FFT graph plot peaks, was calculated to determine the relative degree of fiber alignment. In addition, fluorescently labeled human fibrinogen and mesenchymal stem cells (MSCs) were used to visualize fibrin and cell orientation in aligned and nonaligned plasma clots. Varying degrees of fiber alignment were achieved by the three different methods, with the electric field application producing the highest degree of fiber alignment. The embedded MSCs showed a longitudinal orientation in the electric field-aligned plasma clots. The key feature of this study is the ability to produce autologous plasma clots with aligned fibrin fibers using physical techniques. This orientated internal structure of an autologous biomaterial is promising for distinct therapeutic applications, such as a guiding structure for cell migration and growth dynamics.

Feasibility of an endoscopic approach to the axillary nerve and the nerve to the long head of the triceps brachii with the help of the Da Vinci Robot

Surgery to transfer the axillary nerve and the nerve of the long head of the triceps presents two obstacles: 1) the access portals are not standardized and 2) the nerves are for their larger part approached through large incisions. The goal of this study was to explore the feasibility of an endoscopic microsurgical approach. The posterior aspect of a cadaver shoulder was approached through three communicating mini-incisions. The Da Vinci robot camera was installed on a central trocart, and the instrument arms on the adjacent trocarts. A gas insufflation distended the soft tissues up to the lateral axillary space. The branches of the axillary nerve and the nerve to the long head of the triceps brachii muscle were identified. The dissection of the axillary nerve trunk and its branches was easy. The posterior humeral circumflex veins and artery were dissected as well without any difficulty. Finding the nerve to the long head of the triceps brachii was found to be more challenging because of its deeper location. Robots properties allow performing conventional microsurgery: elimination of the physiologic tremor and multiplication of the movements. They also facilitate the endoscopic approach of the peripheral nerves, as seen in our results on the terminal branches of the axillary nerve and the nerve to the long head of the triceps brachii.

End-to-side nerve repair in a large animal model: how does it compare with conventional methods of nerve repair?

A large animal (sheep) model was used to compare nerve axon regeneration and return of muscle function after a median-to-ulnar nerve end-to-side neurorrhaphy technique with conventional, clinically established, methods of nerve repair and untreated controls. Three groups of sheep were allocated to end-to-side repair (12 animals), a conventional method of nerve repair (18 animals), or a control group (eight animals). After a year nerve repairs were assessed electrophysiologically and histologically, and the muscles supplied by the repaired nerves were assessed physiologically. There were no significant differences in the outcomes of nerve repair between different conventional techniques. Half of the end-to-side nerve repairs supported nerve regeneration. The functional outcomes of the end-to-side repairs were inferior to conventional techniques which were, in turn, inferior to controls. End-to-side neurorrhaphy supported nerve regeneration, but the reliability of this technique is called into question and its use as a clinical tool can only be recommended as a salvage procedure.

Perineural fat grafting in the treatment of painful end-neuromas of the upper limb: a pilot study

The purpose of this study was to evaluate the effectiveness and middle-term durability of the results achieved with perineural fat grafting of painful neuromas of the upper limb. We retrospectively analysed eight patients, affected by eight neuromas, treated by neuroma excision and fat grafting around the proximal nerve stump. Clinical parameters, the disabilities of the arm shoulder and hand score, and the visual analogue scale were recorded at 2, 6 and 12 months after surgery. A reduction of 23.2% was observed in the mean disabilities of the arm shoulder and hand scores at 12 months. The spontaneous baseline visual analogue scale score showed a mean improvement of 22% at 12 months, although not this was not statistically significant. Perineural fat grafting is a quick and useful procedure and could represent a useful primary operation in the treatment of pain syndromes of neuropatic origin.

Use of nerve conduits for peripheral nerve injury repair: A Web of Science-based literature analysis

OBJECTIVE:

To identify global research trends in the use of nerve conduits for peripheral nerve injury repair.

DATA RETRIEVAL:

Numerous basic and clinical studies on nerve conduits for peripheral nerve injury repair were performed between 2002–2011. We performed a bibliometric analysis of the institutions, authors, and hot topics in the field, from the Web of Science, using the key words peripheral nerve and conduit or tube.

SELECTION CRITERIA:

Inclusion criteria: peer-reviewed published articles on nerve conduits for peripheral nerve injury repair, indexed in the Web of Science; original research articles, reviews, meeting abstracts, proceedings papers, book chapters, editorial material, and news items. Exclusion criteria: articles requiring manual searching or telephone access; documents not published in the public domain; and several corrected papers.

MAIN OUTCOME MEASURES:

(a) Annual publication output; (b) publication type; (c) publication by research field; (d) publication by journal; (e) publication by funding agency; (f) publication by author; (g) publication by country and institution; (h) publications by institution in China; (i) most-cited papers.

RESULTS:

A total of 793 publications on the use of nerve conduits for peripheral nerve injury repair were retrieved from the Web of Science between 2002–2011. The number of publications gradually increased over the 10-year study period. Articles constituted the main type of publication. The most prolific journals were Biomaterials, Microsurgery, and Journal of Biomedical Materials Research Part A. The National Natural Science Foundation of China supported 27 papers, more than any other funding agency. Of the 793 publications, almost half came from American and Chinese authors and institutions.

CONCLUSION:

Nerve conduits have been studied extensively for peripheral nerve regeneration; however, many problems remain in this field, which are difficult for researchers to reach a consensus.