Regenerating nerve fiber innervation of extraocular muscles and motor functional changes following oculomotor nerve injuries at different sites

In the present study, the oculomotor nerves were sectioned at the proximal （subtentorial） and distal （superior orbital fissure） ends and repaired. After 24 weeks, vestibulo-ocular reflex evaluation confirmed that the regenerating nerve fibers following oculomotor nerve injury in the superior orbital fissure had a high level of specificity for innervating extraocular muscles. The level of functional recovery of extraocular muscles in rats in the superior orbital fissure injury group was remarkably superior over that in rats undergoing oculomotor nerve injuries at the proximal end （subtentorium）. Horseradish peroxidase retrograde tracing through the right superior rectus muscle showed that the distribution of neurons in the nucleus of the oculomotor nerve was directly associated with the injury site, and that crude fibers were badly damaged. The closer the site of injury of the oculomotor nerve was to the extraocular muscle, the better the recovery of neurological function was. The mechanism may be associated with the aberrant number of regenerated nerve fibers passing through the injury site.

Technical Nuances of Minimal Invasive Interlaminar Decompression in Lumbar Spinal Stenosis: The Role of Minimal Invasive Bilateral Approach

We report a series of patients operated for one or multilevel lumbar spinal stenosis (with and without spondylolisthesis) using the minimal invasive bilateral interlaminar decompression. We discuss our results, comparing this procedure (from a technical point of view) with the muscle-preserving interlaminar decompression (MILD) and the unilateral approach for bilateral decompression (ULBD). Clinical and outcome data of 62 consecutive patients were reviewed, using the Visual Analogue Scale for both low back pain (LBP) and legs pain and the Oswestry Disability Index (ODI) for the degree of disability. Mean age was 68.88 ± 9.54 years and mean follow-up (FU) was 16.38 ± 11.12 months. A statistically significant improvement of LBP, legs pain and ODI was globally observed. At latest FU, patients with multilevel lumbar spinal stenosis significantly improved all scores and patients with spondylolisthesis significantly decreased their disability. No major complications occurred. Two cerebrospinal fluid (CSF) collections were treated conservatively. No wound infection occurred. No progression of spondylolisthesis was observed. No reoperation was needed. Although efficacious in patients with lumbar spinal stenosis, MILD and ULBD can have both some limitations. MILD has been found to decrease lumbar function in multilevel decompression (increasing sagittal translation and lumbar lordosis probably due to the removal of half of the spinous processes) and ULBD shows some disadvantages due to the difficulty of manipulating instruments through a small portal and the inadequate decompression due to a minimal exposure. The minimal invasive bilateral interlaminar decompression (in this technique, the access is bilateral but the supraspinous and interspinous ligaments and the spinous processes are preserved) allows wide access (bilateral exposure) with minimal invasiveness and very low morbidity in patients with lumbar spinal stenosis at one or more levels.

Bringing sensation to prosthetic hands-chronic assessment of implanted thin-film electrodes in humans

Direct stimulation of peripheral nerves with implantable electrodes successfully provided sensory feedback to amputees while using hand prostheses.Longevity of the electrodes is key to success,which we have improved for the polyimide-based transverse intrafascicular multichannel electrode(TIME).The TIMEs were implanted in the median and ulnar nerves of three trans-radial amputees for up to six months.We present a comprehensive assessment of the electrical properties of the thin-film metallization as well as material status post explantationem.The TIMEs stayed within the electrochemical safe limits while enabling consistent and precise amplitude modulation.This lead to a reliable performance in terms of eliciting sensation.No signs of corrosion or morphological change to the thin-film metallization of the probes was observed by means of electrochemical and optical analysis.The presented longevity demonstrates that thin-film electrodes are applicable in permanent implant systems.