In anulus fibrosus samples from macroscopically normal discs, a general marker for nerve endings can be found at a depth of a few millimeters, whereas neuropeptide markers show nerves only in the outermost layers of the anulus fibrosus. This absence of demonstrable nerves in deeper anulus fibrosus in normal discs is probably not a methodologic artifact, because blood vessels have also been demonstrated only at the disc surface. It is, however, possible that neuropeptide nerves also penetrate to a depth of a few millimeters, but that methodologic limitations permit the visualization of only the neuropeptide nerves closest to the disc surface. The results of the present study lend support to previous suggestions that, except at the surface, a normal intervertebral disc is almost without innervation.
Small nerve terminals in disc herniations, both sensory substance P endings and sympathetic C-flanking peptide of neuropeptide Y endings, could be involved in mechanisms of discogenic pain, disc tissue neurogenic inflammation, tissue repair processes after injury, and control of local blood circulation in the newly formed blood vessels. Disc cells may be directly affected by the neuropeptides released from nearby nerve terminals.
The aim of this study was to examine sensory changes of the hand in brachial plexus birth injury (BPBI). Ninety‐five patients (43 females, 52 males) comprising two age groups, 6 to 8 years (mean age 7y 6mo) and 12 to 14 years (mean age 13y 2mo), were included. Sixty‐four had upper (cervical [C] 5–6), 19 upper and middle (C5‐7), and 12 had total (C5‐thoracic (Th)1) plexus injury. Obstetric plexus surgery had been performed on 14 patients at the age of 1 to 6 months. The sensibility of 32 palmar areas of both hands was tested with Semmes‐Weinstein filaments (calibres 2.83, 3.61, 4.31, 4.56, and 6.65). In upper plexus injuries, abnormal values (4.31‐4.56) were recorded in seven out of 64 affected hands. In C5‐7 and total plexus‐involvement, decreased sensibility was found in five out of 19 (4.31‐6.65) and in four out of 12 (4.31‐no sensation) affected hands respectively. Conservatively treated patients had better sensation than those treated surgically. Sensory recovery of the hands in BPBI is generally good, especially in upper plexus injuries. Impairment of fine sensation is not uncommon in more extensive permanent BPBI. In total injuries, protective sensation of the hand is not always restored.
By immunocytochemistry with endothelial cell markers, blood vessels can be observed to be numerous, and their prevalence in herniated discs is very high, presumably as a result of a very intense neovascularization process after the disc injury. A close apposition to disc cells may suggest attempts to increase the nutrition of these cells and will influence the metabolism of the cells.
SummaryIntervertebral disc surgery leads to changes in the segmental anatomy and mobility, and subsequently to degenerative changes in the lumbar spine. Artificial intervertebral disc implants sufficient to replace the human lumbar intervertebral disc have been developed and the requirements for these defined. This is to our knowledge the first study on bioabsorbable intervertebral disc replacement implants. SR-PLLA screws, previously used in orthopaedic internal fixations, and cylindrical implants, specifially developed for this experimental preliminary study, were used to replace lumbar intervertebral discs of growing pigs. After a 15-week follow-up period, the radiological and histological changes in the intervertebral spaces were analyzed. The cylindrical implants were able to prevent narrowing of discectomied spaces, and tissue regeneration in the intervertebral space was induced and occured simultaneously with degradation of the implant.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.