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Ulnar nerve neurotization - Coggle Diagram
Ulnar nerve neurotization
Introduction
Epidemio
most common peripheral nerve injury of the upper limb (United states between 1993 and 2006)
(Lad et al 2010)
Sensibility recovery after acute repair
Despite a microsurgical epineural of fascicular 10-0 suture, within 24 hours after ulnar nerve section; long term results showed that 55% of the patients have not regain any protective sensation
(Vordemvenne et al 2007)
following an interfascicular sural nerve graft, only 28% of the patients were able to report some two-points discrimination after 2 years of minimal follow-up (
Millesi & Berger 1976)
brachial plexus injury
In C8–T1 root injuries, diminished protective sensation was observed on the ulnar aspect of the hand.
(Bertelli et al 2010)
functional consequences of ulnar sensibility loss
Loss of sensation on the ulnar side of the hand leads to injuries like repeated self-mutilation (
Ruchelsman et al 2010)
and functional impairments
part of the sensory recovery relies on the motor recovery
tactile gnosis could not be improve without voluntary motor activity
(Omer et al 1982)
Discussion
LABCN to DoBUN (ETE)
avec greffe
(Oberlin et al 2003)
sans greffe
(Ruchelsman et al 2013)
mais pas d'éval par BMRC
cf Wrinckle test
(O'Riain 1973)
SBRN to SBUN (ETE)
through the 4th intermetacarpal space to the dorsum of the hand
over 12 patients, only 3 of them had recovered a 2PD equals to 6 mm on dIVu and 9 mm on dV, or less
(Matloubi 1988)
Donor zone deficit
(Moore et al 2014)
distal stump of the fascicle of the third webspace could be sutured to the median nerve in an ETS fashion, in order to limit the donor zone deficit
regeneration after peripheral injury
dorsal root ganglion primary sensory neurons : the peripheral branch which innervates the sensory organs, regenerates spontaneously after injury. Conversely, the central branch which enters the spinal cord and terminates in the brain does not, due to myelin-associated inhibitory molecules in their environment. However, thanks to a phenomenon known as conditioning peripheral lesion, a peripheral branch injury can activates the intrinsic growth capacity and overcome the myelin-associated inhibitory effect
(Chen et al 2007)
2 points discrimination test
Reproduciblity under specific stimulus conditions : speed of 5.0 mm/s or 10.0 mm/s + penetration depth of 1.0 mm
(Yokota et al 2020)
¨
lack of standardization, should always be accompanied by a detailed description of the testing protocol, especially regarding the pressure applied.
(Lundborg et al 2004)
could vary with the measurement site
(Catley et al 2013)
dependent on : innervation density, neural pathway, primary sensory cortex cells (S1)
(Lotze et al 2007)
sensory discrimination and cortical reorganisation
(Flor et al 2001)
Slowly adapting type 1 fibers (SA1 fibers) and rapidly adapting type 1 fibers (RA 1 fibers) play a major role in defining the threshold of discriminative touch [17–19]
(Yokoto et al 2020)
2 points discrimination tester Diskirminator, modified by Mackinnon and Dellon
(Mackinnon and Dellon 1985)
vs paperclip or a caliper
descending-ascending or descending with randomization protocol
(Zimney et al 2022)
Mobergs protocole 1958 : final threshold value : smallest distance at which the patient was able to discriminate 7 out of 10 random applications of one or two points
(Jerosh Herold 1993)
dynamic 2PD : lower threshold than static 2PD
(Menier et al 2008)
the static 2-PD test correlates significantly with both tests of integrated hand function even when controlling for the patient’s age, delay before surgery and follow-up time, it should be used rather than the moving 2-PD test.
(jerosh Herold 1993)
M2PD
(Dellon et al 1978)
collateral sprouting is triggered by wallerian degeneration
¨(Lemaitre et al 2020)
Pathophysiology of nerve damage in leprosy relies on M. leprae molecular affinity to Schwann cells, leading to early nerve demyelination mediated by ErB2 receptor tyrosine kinase signaling. Moreover, another in vitro study suggested that M. Leprae triggers glial cell proliferation and inflammatory response
(Wilder-Smith et al 2008)
, leading to appareance of immune-mediated lesions (Aarao et al 2018)*
Wallerian degeneration : anterograde axonal degeneration + demyelinization
(Chen et al 2016)