Axonal regeneration into chronically denervated distal stump

Vuorinen, V.; Siironen, J.; R�ytt�, M.

doi:10.1007/s004010050239

Cited by 2 publications

(4 citation statements)

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“…The observed lower fiber count trend is not surprising given overall nerve atrophy and nerve fiber degeneration following peripheral nerve injury. 23,26,27 Fiber density and packing were both found to be significantly lower in nerves from patients with UVP, while mean g-ratio values were found to be significantly higher. Because of the aforementioned findings that both areas and counts trended lower in paralyzed nerves, it is notable that the decrease in fiber counts was sufficiently more than the decrease in fascicular area so that a significant difference in fiber density was detected.…”

Section: Discussionmentioning

confidence: 84%

“…Previous studies have found that decreased success of reinnervation is linked to degenerative changes in the distal nerve stump which increase in severity with denervation time. 23,24 Therefore, to investigate the role of the chronically denervated RLN in laryngeal reinnervation, we examined morphometric data collected from explanted LRLN sections of paralysis patients with emphasis on the characteristic parameters of myelinated axons and compared those data to control RLNs as well as explored the correlation of those data to time since paralysis onset.…”

Section: Introductionmentioning

confidence: 99%

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Morphometric Differences in the Recurrent Laryngeal Nerve in Patients with Vocal Fold Paralysis

Chao

Howe

Pierce

et al. 2019

Ann Otol Rhinol Laryngol

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Objectives: Injury to the recurrent laryngeal nerve (RLN), if severe enough, can result in vocal fold paralysis. Reinnervation surgery can improve patient outcomes, but previous studies have reported a negative correlation between time since onset of paralysis and surgical outcomes. The ability of the paralyzed nerve to serve as a conduit for donor nerve fibers may be a factor in the success of reinnervation; however, changes in RLN composition after paralysis have not been well studied. Therefore, we investigated the morphometric composition of explanted RLN sections from patients who had experienced vocal fold paralysis for varying length of times. Methods: Nine nerve sections from unilateral vocal fold paralysis (UVP) patients and seven control nerve sections were analyzed for morphometric parameters including fascicular area, fiber count, fiber density, fiber packing, mean g-ratio, and fiber diameter distribution. Nerves from UVP patients were also compared as a function of time since UVP onset. Results: In comparison to control nerves, paralyzed nerves were found to have significantly lower fiber densities and fiber packing, higher mean g-ratio values, and a shift in diameter distributions toward smaller diameter fibers. With respect to paralysis duration, no significant differences were observed except in fiber diameter distributions, where those with paralysis for >2 years had distributions that were significantly shifted toward smaller diameter fibers. Conclusions: The morphometric data presented here suggest that correlations between the time since onset of vocal fold paralysis and reinnervation outcomes may be due to fiber size changes in the paralyzed nerve over time.

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Section: Discussionmentioning

confidence: 84%

Section: Introductionmentioning

confidence: 99%

Morphometric Differences in the Recurrent Laryngeal Nerve in Patients with Vocal Fold Paralysis

Chao

Howe

Pierce

et al. 2019

Ann Otol Rhinol Laryngol

View full text Add to dashboard Cite

show abstract

“…Preliminary observations of regenerated axon profiles in predegenerated stumps 12 months after nerve repair show that regenerated axons are myelinated (Petrov and Gordon, unpublished data). It has also been demonstrated that, even 16 months post denervation, some Schwann cells are capable of synthesizing myelin if they come in contact with regenerating axons (Vuorinen et al, 1995). Thus, atrophic Schwann cells retain a capacity, though limited, for trophic and substrate support and myelination.…”

Section: Long-term Responsementioning

confidence: 99%

“…However, studies of denervation induced changes in gene expression of p75, EGF receptor, and S100 were limited to a period of 3-20 days (Heumann et al, 1987b;Neuberger and Cornbrooks, 1989;Toma et al, 1992). Although light and electron microscopic studies have indicated that Schwann cells and their basement membranes become severely atrophic (Giannini and Dyck, 1990;Roytta and Salonen, 1988;Vuorinen et al, 1995;Weinberg and Spencer, 1978), there has been relatively little interest in the long-term capacity of non-neuronal cells to express regeneration associated genes.…”

Section: Introductionmentioning

confidence: 99%