Perfusion maintains functional potential in denervated mimic muscles in early persistent facial paralysis which requires early microsurgical treatment – the histoanatomic basis of the extratemporal facial nerve trunk assessing axonal load in the context of possible nerve transfers1

Kehrer, Andreas; Engelmann, Simon; Ruewe, Marc; Geis, Sebastian; Taeger, Christian D.; Kehrer, Michael; Tamm, Ernst R.; Bleys, Ronald L. A. W.; Prantl, Lukas; Mandlik, Veronika

doi:10.3233/ch-189905

Cited by 9 publications

(11 citation statements)

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“…Our automated method counted an average axon capacity of 6684 ± 1884 (Range 2655-12457) in facial nerve main trunks (n = 87) 21 . This matches well with average axon quantities found in facial nerve main trunks in several other study groups (Hembd 5329 ± 1376, Captier 6490, Kondo 6245 ± 860) [36][37][38] .…”

Section: Discussionmentioning

confidence: 99%

“…The samples were then serially dehydrated in alcohol and impregnated with epoxy resin. Finally, the labelled samples were embedded in rubber moulds with epoxy resin for 24 hours at 60 °C 21 . After removal from the rubber moulds, the resin blocks were ready for histologic sectioning.…”

Section: Methodsmentioning

confidence: 99%

“…Kehrer et al designed a large macro and microscopic study to further examine anatomical characteristics of the seventh cranial nerve 21,22 . Further morphometry of the fifth cranial nerve was executed (unpublished data).…”

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confidence: 99%

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Rapid and Precise Semi-Automatic Axon Quantification in Human Peripheral Nerves

Engelmann

Ruewe

Geis

et al. 2020

Sci Rep

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We developed a time-efficient semi-automated axon quantification method using freeware in human cranial nerve sections stained with paraphenylenediamine (PPD). It was used to analyze a total of 1238 facial and masseteric nerve biopsies. The technique was validated by comparing manual and semiautomated quantification of 129 (10.4%) randomly selected biopsies. The software-based method demonstrated a sensitivity of 94% and a specificity of 87%. Semi-automatic axon counting was significantly faster (p < 0.001) than manual counting. It took 1 hour and 47 minutes for all 129 biopsies (averaging 50 sec per biopsy, 0.04 seconds per axon). The counting process is automatic and does not need to be supervised. Manual counting took 21 hours and 6 minutes in total (average 9 minutes and 49 seconds per biopsy, 0.52 seconds per axon). Our method showed a linear correlation to the manual counts (R = 0.944 Spearman rho). Attempts have been made by several research groups to automate axonal load quantification. These methods often require specific hard-and software and are therefore only accessible to a few specialized laboratories. Our semi-automated axon quantification is precise, reliable and time-sparing using publicly available software and should be useful for an effective axon quantification in various human peripheral nerves. Microscopic analysis of peripheral nerves is key for many clinical and research based projects. Peripheral nerves have been analyzed through multiple methods, which can generally be categorized into 'manual' , 'automated' and 'semi-automated' methods. Here, the terms for 'manual' and 'fully automated' morphometry will be used as previously described 1-4. 'Semi-automated' will be used synonymously with Urso-Baiardas 'interactive automated' approach; an automated method with the opportunity for manual preparation or alteration 3. In the past, no prime and uniform method could be found, that is simple, cost efficient and time sparing. Therefore, tendentially, small research collectives use manual methods for analysis 1,2,5. Attempts have been made by several research groups throughout medical and scientific research, to automate this process 3,6-8. Unfortunately, it is often found, that these methods are either highly specialized, thus accessible to only few expert laboratories, or, in the case of highly developed software and hardware, very costly 3,9. By example, Marina et al. have coined a method which, similar to this project, focuses on simpler semi-automated anaylsis 10. Other research groups such as Hunter et al. focus on highly specialized methods, which are able to produce a wide range of data and process numerous variables 11. The semi-automated quantification method proposed in this study was developed as part of a greater study on Human facial nerves, for which a time sparing, cost efficient and user-friendly method of axonal quantification was required. Patients with facial palsy, caused by dysfunction of the seventh cranial nerve, suffer emotional distress and are often socially isolated 1...

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Section: Discussionmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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Rapid and Precise Semi-Automatic Axon Quantification in Human Peripheral Nerves

Engelmann

Ruewe

Geis

et al. 2020

Sci Rep

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“…Several studies and classification systems for facial nerve branch patterns already exist (Davis et al, ; Katz and Catalano, ; Kopuz et al, ; Kim et al, ; Gataa and Faris, ). Nerve morphometry and number of fascicles of the extratemporal facial nerve trunk were described in a previous study of ours (Kehrer et al, ).…”

Section: Discussionmentioning

confidence: 95%

Anatomical study of the zygomatic and buccal branches of the facial nerve: Application to facial reanimation procedures

et al. 2019

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The facial nerve is responsible for any facial expression channeling human emotions. Facial paralysis causes asymmetry, lagophthalmus, oral incontinence, and social limitations. Facial dynamics may be re-established with cross-face-nervegrafts (CFNG). Our aim was to reappraise the zygomaticobuccal branch system relevant for facial reanimation surgery with respect to anastomoses and crossings. Dissection was performed on 106 facial halves of 53 fresh frozen cadavers. Study endpoints were quantity and relative thickness of branches, correlation to "Zuker's point", interconnection patterns and crossings. Level I and level II branches were classified as relevant for CFNG. Anastomoses and fusion patterns were assessed in both levels. The zygomatic branch showed 2.98 AE 0.86 (range 2-5) twigs at level II and the buccal branch 3.45 AE 0.96 (range 2-5), respectively. In the zygomatic system a single dominant branch was present in 50%, two co-dominant branches in 9% and three in 1%. In 66% of cases a single dominant buccal twig, two co-dominant in 12.6%, and three in 1% of cases were detected. The most inferior zygomatic branch was the most dominant branch (P = 0.003). Using Zuker's point, a facial nerve branch was found within 5 mm in all facial halves. Fusions were detected in 80% of specimens. Two different types of fusion patterns could be identified. Undercrossing of branches was found in 24% at levels I and II. Our study describes facial nerve branch systems relevant for facial reanimation surgery in a three-dimensional relationship of branches to each other. Clin. Anat. 32:480-488, 2019.

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“…Pelo fato de inervar cerca de vinte e quatro músculos da mímica facial, o sétimo par de nervo craniano intermedia importante papel na comunicação verbal e não verbal. Assim, disfunções no nervo facial podem causar graves prejuízos funcionais, motores, estéticos e sociais (KEHRER et al, 2018). Tais disfunções podem ser secundárias a traumas, patologias e manipulações cirúrgicas (CHHABRA et al, 2018), situações em que o conhecimento sobre marcos anatômicos como a VRM é essencial para prevenção de lesões no nervo .…”

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