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Kollech HG, Chao MR, Stark AC, German RZ, Paniello RC, Christensen MB, Barkmeier-Kraemer JM, Vande Geest JP. Extracellular matrix deformations of the porcine recurrent laryngeal nerve in response to hydrostatic pressure. Acta Biomater 2022; 153:364-373. [PMID: 36152909 PMCID: PMC10627241 DOI: 10.1016/j.actbio.2022.09.039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2021] [Revised: 08/22/2022] [Accepted: 09/15/2022] [Indexed: 11/25/2022]
Abstract
Damage to the recurrent laryngeal nerve (RLN) caused by supraphysiological compression or tension imposed by adjacent tissue structures, such as the aorta, may contribute to onset of idiopathic unilateral vocal fold paralysis (iUVP) resulting in difficulty speaking, breathing, and swallowing. We previously demonstrated in adolescent pigs that the right RLN epineurium exhibits uniform composition of adipose tissue, with larger quantities along its length within the neck region in contrast to the left RLN that shows greater collagen composition in the thoracic region and greater quantities of adipose tissue in the neck region. In contrast, the epineurium in piglets was primarily composed of collagen tissue that remained uniform along the length of the left and right RLNs. Tensile testing of the left and right RLN in piglets and pigs showed associated differences in strain by RLN side and segment by age. The goal of this study was to investigate how external hydrostatic compression of the RLN affects the nerve's connective tissue and microstructure. RLN segments were harvested from the distal (cervical/neck) regions and proximal (subclavian for the right RLN, thoracic for the left RLN) regions from eight adolescent pigs and nine piglets. RLN segments were isolated and assessed under fluid compression to test hypotheses regarding epineurium composition and response to applied forces. Second harmonic generation (SHG) imaging of epineurial collagen was conducted at 0, 40, and 80 mmHg of compression. The cartesian strain tensor, principal strain (Eps1), and principal direction of the RLN collagen fibers were determined at each pressure step. Significantly larger values of the 1st principal strain occurred in the proximal segments of the pig left RLN when compared to the same segment in piglets (p = 0.001, pig = 0.0287 [IQR = 0.0161 - 0.0428], piglet = 0.0061 [IQR = 0.0033 - 0.0156]). Additionally, the median transverse strain Eyy) for the second pressure increment was larger in the right proximal segment of pigs compared to piglets (p < 0.001, pig = 0.0122 [IQR = 0.0033 - 0.0171], piglet = 0.0013 [IQR = 0.00001 - 0.0028]). Eyy values were significantly larger in the right proximal RLN versus the left proximal RLNs in pigs but not in piglets (p < 0.001). In contrast to piglets, histological analysis of pig RLN demonstrated increased axial alignment of epineurial and endoneurial collagen in response to compressive pressure. These findings support the hypothesis that the biomechanical response of the RLN to compressive pressure changed from being similar to being different between the right and left RLNs during development in the porcine model. Further investigation of these findings associated with age-related onset of idiopathic UVP may illuminate underlying etiologic mechanisms. STATEMENT OF SIGNIFICANCE: Damage to the recurrent laryngeal nerve (RLN) caused by compression imposed by the aorta may contribute to the onset of left-sided idiopathic unilateral vocal fold paralysis resulting in difficulty speaking, breathing, and swallowing. The goal of this study was to investigate how compression affects the connective tissue and microstructure of the RLN. We quantified the pressure induced deformation of the RLN using multiphoton imaging as a function of both location (proximal versus distal) and age (piglets, adolescent pigs). Our results demonstrate that the biomechanical response of the RLN to compression changes in the right versus left RLN throughout development, providing further evidence that the the left RLN is exposed to increasing dynamic loads with age.
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Affiliation(s)
- Hirut G Kollech
- Computational Modeling and Simulation Program, University of Pittsburgh, Pittsburgh, PA, USA
| | - Melissa R Chao
- Department of Bioengineering, University of Utah, Salt Lake City, UT, USA
| | - Amanda C Stark
- National Center for Voice and Speech, University of Utah, Salt Lake City, UT, USA
| | - Rebecca Z German
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University (NEOMED), Rootstown, OH, USA
| | - Randal C Paniello
- Department of Otolaryngology - Head and Neck Surgery, Washington University School of Medicine, St. Louis, MO, USA
| | | | - Julie M Barkmeier-Kraemer
- Department of Surgery, Division of Otolaryngology-Head and Neck Surgery, University of Utah, UT, USA
| | - Jonathan P Vande Geest
- Department of Bioengineering, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, PA, USA; McGowan Institute for Regenerative Medicine, University of Pittsburgh, Pittsburgh, PA, USA; Department of Mechanical Engineering and Material Science, Swanson School of Engineering, University of Pittsburgh, Pittsburgh, PA, USA.
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Im JH, Shin SH, Lee MK, Lee SR, Lee JJ, Chung YG. Evaluation of anatomical and histological characteristics of human peripheral nerves: as an effort to develop an efficient allogeneic nerve graft. Cell Tissue Bank 2022; 23:591-606. [DOI: 10.1007/s10561-022-09998-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Accepted: 02/13/2022] [Indexed: 12/14/2022]
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Troiani F, Nikolic K, Constandinou TG. Simulating optical coherence tomography for observing nerve activity: A finite difference time domain bi-dimensional model. PLoS One 2018; 13:e0200392. [PMID: 29990346 PMCID: PMC6039043 DOI: 10.1371/journal.pone.0200392] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2018] [Accepted: 06/24/2018] [Indexed: 11/19/2022] Open
Abstract
We present a finite difference time domain (FDTD) model for computation of A line scans in time domain optical coherence tomography (OCT). The OCT output signal is created using two different simulations for the reference and sample arms, with a successive computation of the interference signal with external software. In this paper we present the model applied to two different samples: a glass rod filled with water-sucrose solution at different concentrations and a peripheral nerve. This work aims to understand to what extent time domain OCT can be used for non-invasive, direct optical monitoring of peripheral nerve activity.
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Affiliation(s)
- Francesca Troiani
- Centre for Bio-Inspired Technology, Imperial College London, London, United Kingdom
| | - Konstantin Nikolic
- Centre for Bio-Inspired Technology, Imperial College London, London, United Kingdom
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Williams MJ, Ayylasomayajula A, Behkam R, Bierhals AJ, Jacobs ME, Edgar JD, Paniello RC, Barkmeier-Kraemer JM, Vande Geest JP. A computational study of the role of the aortic arch in idiopathic unilateral vocal-fold paralysis. J Appl Physiol (1985) 2014; 118:465-74. [PMID: 25477351 DOI: 10.1152/japplphysiol.00638.2014] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Unilateral vocal-fold paralysis (UVP) occurs when one of the vocal folds becomes paralyzed due to damage to the recurrent laryngeal nerve (RLN). Individuals with UVP experience problems with speaking, swallowing, and breathing. Nearly two-thirds of all cases of UVP is associated with impaired function of the left RLN, which branches from the vagus nerve within the thoracic cavity and loops around the aorta before ascending to the larynx within the neck. We hypothesize that this path predisposes the left RLN to a supraphysiological, biomechanical environment, contributing to onset of UVP. Specifically, this research focuses on the identification of the contribution of the aorta to onset of left-sided UVP. Important to this goal is determining the relative influence of the material properties of the RLN and the aorta in controlling the biomechanical environment of the RLN. Finite element analysis was used to estimate the stress and strain imposed on the left RLN as a function of the material properties and loading conditions. The peak stress and strain in the RLN were quantified as a function of RLN and aortic material properties and aortic blood pressure using Spearman rank correlation coefficients. The material properties of the aortic arch showed the strongest correlation with peak stress [ρ = -0.63, 95% confidence interval (CI), -1.00 to -0.25] and strain (ρ = -0.62, 95% CI, -0.99 to -0.24) in the RLN. Our results suggest an important role for the aorta in controlling the biomechanical environment of the RLN and potentially in the onset of left-sided UVP that is idiopathic.
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Affiliation(s)
- Megan J Williams
- Graduate Interdisciplinary Program of Biomedical Engineering, University of Arizona, Tucson, Arizona
| | | | - Reza Behkam
- Department of Aerospace and Mechanical Engineering, University of Arizona, Tucson, Arizona
| | - Andrew J Bierhals
- Mallinckrodt Institute of Radiology, Washington University School of Medicine, St. Louis, Missouri
| | - M Eileen Jacobs
- Mallinckrodt Institute of Radiology, Washington University School of Medicine, St. Louis, Missouri
| | | | - Randal C Paniello
- Department of Otolaryngology-Head and Neck Surgery, Washington University School of Medicine, St. Louis, Missouri
| | - Julie M Barkmeier-Kraemer
- Department of Surgery, Division of Otolaryngology-Head and Neck Surgery, Voice Laboratory, University of Utah, Salt Lake City, Utah
| | - Jonathan P Vande Geest
- Graduate Interdisciplinary Program of Biomedical Engineering, University of Arizona, Tucson, Arizona; Department of Aerospace and Mechanical Engineering, University of Arizona, Tucson, Arizona; Department of Biomedical Engineering, University of Arizona, Tucson, Arizona; and BIO5 Institute, University of Arizona, Tucson, Arizona
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5
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Jensen VFH, Mølck AM, Bøgh IB, Lykkesfeldt J. Effect of insulin-induced hypoglycaemia on the peripheral nervous system: focus on adaptive mechanisms, pathogenesis and histopathological changes. J Neuroendocrinol 2014; 26:482-96. [PMID: 24921897 DOI: 10.1111/jne.12170] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/16/2014] [Revised: 05/22/2014] [Accepted: 06/05/2014] [Indexed: 12/31/2022]
Abstract
Insulin-induced hypoglycaemia (IIH) is a common acute side effect in type 1 and type 2 diabetic patients, especially during intensive insulin therapy. The peripheral nervous system (PNS) depends on glucose as its primary energy source during normoglycaemia and, consequently, it may be particularly susceptible to IIH damage. Possible mechanisms for adaption of the PNS to IIH include increased glucose uptake, utilisation of alternative energy substrates and the use of Schwann cell glycogen as a local glucose reserve. However, these potential adaptive mechanisms become insufficient when the hypoglycaemic state exceeds a certain level of severity and duration, resulting in a sensory-motor neuropathy with associated skeletal muscle atrophy. Large myelinated motor fibres appear to be particularly vulnerable. Thus, although the PNS is not an obligate glucose consumer, as is the brain, it appears to be more prone to IIH than the central nervous system when hypoglycaemia is not severe (blood glucose level ≤ 2 mm), possibly reflecting a preferential protection of the brain during periods of inadequate glucose availability. With a primary focus on evidence from experimental animal studies investigating nondiabetic IIH, the present review discusses the effect of IIH on the PNS with a focus on adaptive mechanisms, pathogenesis and histological changes.
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Affiliation(s)
- V F H Jensen
- Department of Veterinary Disease, Biology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark; Department of Diabetes Toxicology and Safety Pharmacology, Novo Nordisk A/S, Maaloev, Denmark
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Morphologic Evaluation of the Fetal Recurrent Laryngeal Nerve and Motor Units in the Thyroarytenoid Muscle. J Voice 2013; 27:668-73. [DOI: 10.1016/j.jvoice.2013.07.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2013] [Accepted: 07/10/2013] [Indexed: 11/18/2022]
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Campbell EO, Samlan RA, McMullen NT, Cook S, Smiley-Jewell S, Barkmeier-Kraemer J. Developmental changes in the connective tissues of the porcine recurrent laryngeal nerve. J Anat 2013; 222:625-33. [PMID: 23590663 DOI: 10.1111/joa.12046] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/11/2013] [Indexed: 11/26/2022] Open
Abstract
The recurrent laryngeal nerve (RLN) branches from the vagus cranial nerve to innervate structures important for voicing and swallowing. Damage to this nerve, commonly associated with surgery or idiopathic etiologies that largely occur with aging, results in impaired voicing and swallowing (Myssiorek, 2004). Sunderland proposed a model of peripheral nerve damage whereby a nerve's ability to resist damage from stretch and compression is determined by the quantity and composition of its epineurial connective tissues (Sunderland, 1951). Thus, it would be expected that epineurium differs depending upon the forces imposed on a nerve within its anatomical setting. The purpose of this study was to investigate RLN epineurium quantity and composition with development. A porcine model (piglet vs. juvenile) was used because of the similarity between porcine and human laryngeal innervation, anatomy and function. The entire RLN was excised bilaterally, and stereological methods were used to quantify the composition of epineurial connective tissues. Compared with the piglet, the juvenile pig RLN was double the diameter. While the piglet had no differences in the percentage of epineurial collagen and adipose between proximal and distal segments of both sides of the RLN, the juvenile pig had a greater percentage of collagen in the proximal segment of both sides of the RLN and a greater percentage of adipose in the distal segment of the left RLN compared with the proximal segment. In addition, unlike the piglet, the juvenile pig had a greater number of fascicles in the proximal than distal segment of the RLN, regardless of nerve side. These findings are consistent with predicted patterns associated with the different anatomical settings of the left and right RLN, show that the RLN changes with age, and support Sunderland's model.
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Affiliation(s)
- Ellen O Campbell
- Department of Speech, Language, Hearing, University of Arizona, Tucson, AZ, USA
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Nadra K, Médard JJ, Quignodon L, Verheijen MHG, Desvergne B, Chrast R. Epineurial adipocytes are dispensable for Schwann cell myelination. J Neurochem 2012; 123:662-7. [PMID: 22849425 DOI: 10.1111/j.1471-4159.2012.07896.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2012] [Revised: 07/11/2012] [Accepted: 07/12/2012] [Indexed: 12/18/2022]
Abstract
Previous clinical observations and data from mouse models with defects in lipid metabolism suggested that epineurial adipocytes may play a role in peripheral nervous system myelination. We have used adipocyte-specific Lpin1 knockout mice to characterize the consequences of the presence of impaired epineurial adipocytes on the myelinating peripheral nerve. Our data revealed that the capacity of Schwann cells to establish myelin, and the functional properties of peripheral nerves, were not affected by compromised epineurial adipocytes in adipocyte-specific Lpin1 knockout mice. To evaluate the possibility that Lpin1-negative adipocytes are still able to support endoneurial Schwann cells, we also characterized sciatic nerves from mice carrying epiblast-specific deletion of peroxisome proliferator-activated receptor gamma, which develop general lipoatrophy. Interestingly, even the complete loss of adipocytes in the epineurium of peroxisome proliferator-activated receptor gamma knockout mice did not lead to detectable defects in Schwann cell myelination. However, probably as a consequence of their hyperglycemia, these mice have reduced nerve conduction velocity, thus mimicking the phenotype observed under diabetic condition. Together, our data indicate that while adipocytes, as regulators of lipid and glucose homeostasis, play a role in nerve function, their presence in epineurium is not essential for establishment or maintenance of proper myelin.
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Affiliation(s)
- Karim Nadra
- Department of Medical Genetics, University of Lausanne, Lausanne, Switzerland
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Prasad K, P BK, Chakravarthy M, Prabhu G. Applications of 'TissueQuant'- a color intensity quantification tool for medical research. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2012; 106:27-36. [PMID: 21924792 DOI: 10.1016/j.cmpb.2011.08.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/05/2011] [Revised: 06/05/2011] [Accepted: 08/20/2011] [Indexed: 05/31/2023]
Abstract
This paper demonstrates the use of TissueQuant - an image analysis tool for quantification of color intensities which was developed for use in medical research where the stained biological specimen such as tissue or antigen needs to be quantified. TissueQuant provides facilities for user interaction to choose and quantify the color of interest and its shades. Gaussian weighting functions are used to provide a color score which quantifies how close the shade is to the user specified reference color. We describe two studies in medical research which use TissueQuant for quantification. The first study evaluated the effect of petroleum-ether extract of Cissus quadrangularis (CQ) on osteoporotic rats. It was found that the analysis results correlated well with the manual evaluation, p < 0.001. The second study evaluated the nerve morphometry and it was found that the adipose and non adipose tissue content was maximum in radial nerve among the five nerves studied.
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Affiliation(s)
- Keerthana Prasad
- Manipal Centre for Information Science, Manipal University, India.
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Marx Chakravarthy S, Kumar P, Dhalapathy S, Marx A. A comparative microanatomical study on cross-sections of superficial branch of radial nerve in proximal and distal parts of the forearm: a cadaveric study. Morphologie 2010; 94:98-106. [PMID: 20951622 DOI: 10.1016/j.morpho.2010.03.009] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
PURPOSE OF STUDY Changes in peripheral nerve anatomy with age may be the cause for poor prognosis after nerve repair in elderly cases. The aim of the present study is to find out and compare the cross-sectional microanatomy as well as age-related changes in the non-fascicular components of superficial branch of radial nerve at cubital fossa (SBRN-1) and above wrist (SBRN-2). METHODS Thirty-eight fresh human (14 male and five female) cadaveric SBRN-1 and SBRN-2 were collected from both sides of 19 cadavers and study has been performed at different magnifications after routine histological (Masson's trichrome stain) processing was done for morphometric analysis (total cross-sectional area [Asc], fascicular area [Af], non-Af [Anonf], adipose [FAT] area and non-adipose area [nFAT]). RESULTS SBRN-1 and SBRN-2 belonged to polyfascicular type and showed difference in amount of connective and adipose tissues in Anonf. The number of fascicles in SBRN-1 ranged from 2 to 6 (3.66±0.21, mean±SEM) and in SBRN-2 ranged from 7.5 to 11.5 (9.24±0.26). On comparing the percentage level of adipose tissue (FAT) in total cross-section area (Asc) and in Anonf of SBRN-1 and SBRN-2, the level of adipose tissue was increased with age. CONCLUSIONS The amount of adipose tissue in SBRN-1 and SBRN-2 Anonf was found to be high in most of the elderly cases. On comparison, there was not much difference between SBRN-1 and SBRN-2, but, the fascicle count was found to be increasing gradually from proximal to distal part of the SBRN.
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Affiliation(s)
- S Marx Chakravarthy
- Department of Anatomy, Kasturba Medical College, 576104 Manipal, Karnataka, India.
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Ray B, D'Souza A, Kumar B, Marx C, Ghosh B, Gupta NK, Marx A. Variations in the course and microanatomical study of the lateral femoral cutaneous nerve and its clinical importance. Clin Anat 2010; 23:978-84. [DOI: 10.1002/ca.21043] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Marx SC, Kumar P, Dhalapathy S, Prasad K, Marx CA. Microanatomical and immunohistochemical study of the human lateral antebrachial cutaneous nerve of forearm at the antecubital fossa and its clinical implications. Clin Anat 2010; 23:693-701. [DOI: 10.1002/ca.20985] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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Marx SC, Kumar P, Dhalapathy S, Anitha Marx C. A comparative microanatomical study on cross sections of medial and lateral cutaneous nerves of forearm at the antecubital fossa: a cadaveric study. Ann Anat 2010; 192:107-15. [PMID: 20138488 DOI: 10.1016/j.aanat.2009.12.004] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2009] [Revised: 12/15/2009] [Accepted: 12/16/2009] [Indexed: 10/19/2022]
Abstract
BACKGROUND The anterior branch of the medial antebrachial cutaneous nerve of the forearm (AMACN) and the lateral antebrachial cutaneous nerve of the forearm (LACN) are used as potential donor grafts for repairing sensory nerves. A higher percentage of connective tissue plays an important role in predicting prognosis after nerve repair. The aim is to perform a comparative study on cross-sectional microanatomy and age related changes in non-fascicular components of the AMACN and LACN. METHODS Thirty six fresh human (from both sides of 14 male and 4 female) cadaveric AMACN and LACN were collected at antecubital fossae and studied at different magnifications for morphometric analysis (total cross-sectional area (Asc), fascicular area (Af) and non-fascicular area (Anonf)), after histological (Masson's trichrome stain) processing. RESULTS AMACN and LACN belong to polyfascicular type and showed differences in amount of connective and adipose tissues in non-fascicular areas. In the AMACN, there was less adipose tissue (19.38% in Asc and 25.57% in Anonf) with more collagen fibers (57.28% in Asc and 75.57% in Anonf) and in the LACN, there was more adipose tissue (47.51% in Asc and 58.19% in Anonf) with fewer collagen fibers (34.10% in Asc and 41.76% in Anonf) in interfascicular domains. CONCLUSIONS The amount of adipose tissue in LACN non-fascicular area was found to be high at all ages. The presence of less adipose tissue and collagen fibers in the non-fascicular area of the AMACN (below 60 years) could be used for successful nerve grafting when compared to LACN.
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Affiliation(s)
- S Chakravarthy Marx
- Department of Anatomy, Kasturba Medical College, Madhav nagar, Manipal 576104, Karnataka, India.
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Alexander MJ, Barkmeier-Kraemer JM, Vande Geest JP. Biomechanical properties of recurrent laryngeal nerve in the piglet. Ann Biomed Eng 2010; 38:2553-62. [PMID: 20369296 DOI: 10.1007/s10439-010-0013-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2009] [Accepted: 03/12/2010] [Indexed: 10/19/2022]
Abstract
Unilateral vocal fold paralysis (UVP) results from damage to the recurrent laryngeal nerve (RLN). The most common causes of UVP are associated with compromised RLN tissue. The purpose of this research was to investigate the biomechanical properties of piglet RLN and identify differences in these properties along its length and in between the left and right side. Quasi-static uniaxial tensile testing and isotropic constitutive modeling was performed on seven piglet RLNs. Stiffness and other biomechanical parameters were derived from these tests and compared from conducting two different statistical analysis for the between and within nerve comparisons. Results showed higher stiffness values in the left RLN segment than for the right. Descriptive data demonstrated a higher stiffness in RLN segments surrounding the aortic arch, indicating a more protective role of the extracellular matrix in these nerves. This research offers insight regarding the protective function of the RLN connective tissues and structural compromise due to its environment.
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Affiliation(s)
- Megan J Alexander
- Department of Aerospace and Mechanical Engineering, Soft Tissue Biomechanics Laboratory, University of Arizona, 1130 N Mountain Ave., PO Box 210119, Tucson, AZ 85721-0119, USA
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Jotz GP, de Campos D, Rodrigues MF, Xavier LL. Histological asymmetry of the human recurrent laryngeal nerve. J Voice 2010; 25:8-14. [PMID: 20083375 DOI: 10.1016/j.jvoice.2009.06.007] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2008] [Accepted: 06/23/2009] [Indexed: 11/30/2022]
Abstract
Histological studies of the human recurrent laryngeal nerves (RLNs) have described differences in fiber length and thickness between the right and left RLNs. This asymmetry is probably involved in the different times of arrival of the stimuli to the laryngeal musculature controlled by each nerve. Histological and structural differences between the right and left RLNs could explain the synchronicity of laryngeal musculature contraction despite the differing nerve lengths. The purpose of this investigation was to shed some light on this paradigm by obtaining estimates of some morphometric parameters, such as intraperineural area, intraperineural perimeter, fiber area, fiber perimeter, fiber density (number of fibers/mm(2)), and total number of fibers in the right and left RLN of humans. Thus, the right and left RLNs were studied in a total sample of eight human specimens obtained from necropsies. The nerves were analyzed using histology, and the morphometric parameters were measured using Image Pro Plus Software 4.1 (Media Cybernetics, Silver Spring, MD, USA). No statistical differences between the two RLNs were observed in the intraperineural area, intraperineural perimeter, density (number of fibers/mm(2)), and total number of fibers. However, the area and perimeter of fibers of the right RLN were statistically larger when compared with those of the left RLN--21% and 11%, respectively. In conclusion, we show that in humans, the area and perimeter of the right RLN are larger than those of the left RLN. This morphological finding is probably related to the different time of arrival of the stimulus to the laryngeal musculature.
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Affiliation(s)
- Geraldo Pereira Jotz
- Programa de Pós Graduação em Neurociências, Instituto de Ciências Básicas da Saúde, Universidade Federal do Rio Grande do Sul, Porto Alegre, Rio Grande do Sul, Brazil
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Chakravarthy Marx S, Kumar P, Dhalapathy S, Prasad K, Anitha Marx C. Microanatomical and immunohistochemical study of the human radial nerve at the antecubital fossa. Ann Anat 2009; 191:389-98. [DOI: 10.1016/j.aanat.2009.04.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2009] [Revised: 04/24/2009] [Accepted: 04/27/2009] [Indexed: 01/22/2023]
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17
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Microanatomical structure of the human sciatic nerve. Surg Radiol Anat 2008; 30:619-26. [DOI: 10.1007/s00276-008-0386-6] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2008] [Accepted: 05/29/2008] [Indexed: 11/25/2022]
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