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Honis HR, Gruber H, Honold S, Konschake M, Moriggl B, Brenner E, Skalla-Oberherber E, Loizides A. Anatomical considerations of US-guided carpal tunnel release in daily clinical practice. J Ultrason 2023; 23:e131-e143. [PMID: 37732109 PMCID: PMC10508271 DOI: 10.15557/jou.2023.0022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Accepted: 04/28/2023] [Indexed: 09/22/2023] Open
Abstract
Carpal tunnel syndrome is the most frequent compression neuropathy with an incidence of one to three subjects per thousand. As specific anatomical variations might lead to unintended damage during surgical interventions, we present a review to elucidate the anatomical variability of the carpal tunnel region with important considerations for daily clinical practice: several variants of the median nerve branches in and around the transverse carpal ligament are typical and must - similarly to the variant courses of the median artery, which may be found eccentric ulnar to the median nerve - be taken into account in any interventional therapy at the carpal tunnel. Unintended interference in these structures might lead to heavy arterial bleeding and, in consequence, even underperfusion of segments of the median nerve or, if neural structures such as variant nerve branches are impaired or even cut, severe pain-syndromes with a profound impact on the quality of life. This knowledge is thus crucial for outcome- and safety-optimization of different surgical procedures at the volar aspect of the wrist and surgical therapy of the carpal tunnel syndrome e.g., US-guided carpal tunnel release, as injury might result in dysfunction and/or pain on wrist motion or direct impact in the region concerned. For most variations, anatomical and surgical descriptions vary, as official classifications are still lacking.
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Affiliation(s)
- Hanne-Rose Honis
- Institute of Clinical and Functional Anatomy, Medical University Innsbruck, Innsbruck, Austria
| | - Hannes Gruber
- Department of Radiology, Medical University Innsbruck, Innsbruck, Austria
| | - Sarah Honold
- Department of Radiology, Medical University Innsbruck, Innsbruck, Austria
| | - Marko Konschake
- Institute of Clinical and Functional Anatomy, Medical University Innsbruck, Innsbruck, Austria
| | - Bernhard Moriggl
- Institute of Clinical and Functional Anatomy, Medical University Innsbruck, Innsbruck, Austria
| | - Erich Brenner
- Institute of Clinical and Functional Anatomy, Medical University Innsbruck, Innsbruck, Austria
| | | | - Alexander Loizides
- Department of Radiology, Medical University Innsbruck, Innsbruck, Austria
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Li ZM. Non-Surgical Carpal Arch Space Augmentation for Median Nerve Decompression. J Biomech Eng 2023; 145:080801. [PMID: 36628998 PMCID: PMC10259465 DOI: 10.1115/1.4056651] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Revised: 01/04/2023] [Accepted: 01/07/2023] [Indexed: 01/12/2023]
Abstract
The carpal tunnel is a tightly bounded space, making the median nerve prone to compression and eventually leading to carpal tunnel syndrome. Carpal tunnel release surgery transects the transverse carpal ligament to expand the tunnel arch space, decompress the median nerve, and relieve the associated symptoms. However, the surgical procedure unavoidably disrupts essential anatomical, biomechanical and physiological functions of the wrist, potentially causing reduced grip strength, pillar pain, carpal bone instability, scar tissue formation, and perineural fibrosis. It is desirable to decompress the median nerve without surgically transecting the transverse carpal ligament. This paper is to review several approaches we have developed for nonsurgical carpal arch space augmentation (CASA), namely, radio ulnar wrist compression, muscle-ligament interaction, palmar pulling, and collagenolysis of the transverse carpal ligament. Briefly summarized is the research work on the CASA topic about theoretical considerations, in vitro and in situ experiment, computational modeling, and human subject studies with asymptomatic and carpal tunnel syndrome hands.
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Affiliation(s)
- Zong-Ming Li
- Departments of Orthopaedic Surgery and Biomedical Engineering, Hand Research Laboratory, University of Arizona, Tucson, AZ 85724
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Peng L, Wu Y, Lakshminarayanan K, Zhang A, Gan Y, Li Y, Yao Y. The relationship between shear wave velocity in transverse carpal ligament and carpal tunnel pressure: A finite element analysis. Med Eng Phys 2023; 116:103995. [PMID: 37230698 DOI: 10.1016/j.medengphy.2023.103995] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2022] [Revised: 05/12/2023] [Accepted: 05/14/2023] [Indexed: 05/27/2023]
Abstract
Elevated carpal tunnel pressure in carpal tunnel syndrome (CTS) patients is one of the major causes of nerve damage but cannot be measured non-invasively. This study proposed to use shear wave velocity (SWV) in the transverse carpal ligament (TCL) to measure the surrounding carpal tunnel pressure. The relationship between the carpal tunnel pressure and the SWV in the TCL was investigated through a subject-specific carpal tunnel finite element model reconstrued by MRI imaging. Parametric analysis was conducted to study the effect of TCL Young's modulus and carpal tunnel pressure on the TCL SWV. The SWV in TCL was found to be strongly dependent on the carpal tunnel pressure and TCL Young's modulus. The calculated SWV ranged from 8.0 m/s to 22.6 m/s under a combination of carpal tunnel pressure (0-200 mmHg) and TCL Young's modulus (1.1-11 MPa). An empirical equation was used to fit the relationship between the SWV in TCL and carpal tunnel pressure, with TCL Young's modulus as a confounding factor. The equation proposed in this study provided an approach to estimate carpal tunnel pressure by measuring the SWV in the TCL for a potential non-invasive diagnosis of CTS and may shed light on the mechanical nerve damage mechanism.
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Affiliation(s)
- Linjing Peng
- School of Biomedical Engineering, Shanghai Jiao Tong University, 1954 Huashan Road, Shanghai, 200030, China; Engineering Research Center of Digital Medicine and Clinical Translation, Ministry of Education, Shanghai Jiao Tong University, 1954 Huashan Road, Shanghai, 200030, China
| | - Yu Wu
- School of Biomedical Engineering, Shanghai Jiao Tong University, 1954 Huashan Road, Shanghai, 200030, China; Olin College of Engineering, 1000 Olin Way, Needham, 02492, US
| | - Kishor Lakshminarayanan
- Department of Sensors and Biomedical Engineering, Vellore Institute of Technology, Ranipet Katpadi Road Vellore, 632 014, Tamil Nadu, India
| | - Aili Zhang
- School of Biomedical Engineering, Shanghai Jiao Tong University, 1954 Huashan Road, Shanghai, 200030, China
| | - Yaokai Gan
- Engineering Research Center of Digital Medicine and Clinical Translation, Ministry of Education, Shanghai Jiao Tong University, 1954 Huashan Road, Shanghai, 200030, China; Department of Orthopedics, Shanghai Ninth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, 639 Zhizaoju Road, Shanghai, China, 200011
| | - Yiming Li
- Department of Orthopedics, Shanghai Ninth People's Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, 639 Zhizaoju Road, Shanghai, China, 200011
| | - Yifei Yao
- School of Biomedical Engineering, Shanghai Jiao Tong University, 1954 Huashan Road, Shanghai, 200030, China; Engineering Research Center of Digital Medicine and Clinical Translation, Ministry of Education, Shanghai Jiao Tong University, 1954 Huashan Road, Shanghai, 200030, China.
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Zhang H, Jordan D, Li ZM. Carpal arch space increased by volar force applied to the skin surface above the carpal tunnel. Clin Biomech (Bristol, Avon) 2023; 102:105888. [PMID: 36640747 PMCID: PMC9975036 DOI: 10.1016/j.clinbiomech.2023.105888] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Revised: 12/23/2022] [Accepted: 01/09/2023] [Indexed: 01/12/2023]
Abstract
BACKGROUND Carpal arch space augmentation can help decompress the median nerve. The augmentation can be achieved by mechanical manipulations utilizing the biomechanics of the tunnel structure. The purpose of this study was to expand the carpal arch in vitro by applying volar forces on the surface of the wrist. METHODS The mechanism was implemented in eight cadaver hands by attaching a volar force transmitter to the palmar surface of the wrist and pulling the transmitter volarly at six force levels (0, 3, 6, 9, 12, and 15 N). Ultrasound images of the cross section at the distal carpal tunnel were collected for morphological analysis. FINDINGS The carpal arch height, width, and area were significantly altered by the volarly applied force (P < 0.001). The arch height and area were increased but the arch width was decreased by the force. Pearson's correlation coefficient showed that there was a positive correlation between the arch height and force magnitude; and between the arch area and force magnitude. A negative correlation existed between the arch width and force magnitude (P < 0.001). The magnitude of change of the arch height, width, and area was increased as the force magnitude increased. INTERPRETATION This study demonstrated that applying external forces on the wrist skin to increase the carpal arch space was feasible. The magnitude of the force influenced its effect on altering the carpal arch. Study limitations include small sample size and inclusion of male specimens. Future in vivo work is needed for clinical translation feasibility.
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Affiliation(s)
- Hui Zhang
- Hand Research Laboratory, Department of Orthopaedic Surgery and Arthritis Center, University of Arizona College of Medicine, Tucson, USA
| | - David Jordan
- Hand Research Laboratory, Department of Orthopaedic Surgery and Arthritis Center, University of Arizona College of Medicine, Tucson, USA
| | - Zong-Ming Li
- Hand Research Laboratory, Department of Orthopaedic Surgery and Arthritis Center, University of Arizona College of Medicine, Tucson, USA; Department of Biomedical Engineering, University of Arizona, Tucson, USA.
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Li ZM, Jordan DB. Carpal tunnel mechanics and its relevance to carpal tunnel syndrome. Hum Mov Sci 2023; 87:103044. [PMID: 36442295 PMCID: PMC9839559 DOI: 10.1016/j.humov.2022.103044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2022] [Accepted: 11/20/2022] [Indexed: 11/27/2022]
Abstract
The carpal tunnel is an elaborate biomechanical structure whose pathomechanics plays an essential role in the development of carpal tunnel syndrome. The purpose of this article is to review the movement related biomechanics of the carpal tunnel together with its anatomical and morphological features, and to describe the pathomechanics and pathophysiology associated with carpal tunnel syndrome. Topics of discussion include biomechanics of the median nerve, flexor tendons, subsynovial tissue, transverse carpal ligament, carpal tunnel pressure, and morphological properties, as well as mechanisms for biomechanical improvement and physiological restoration. It is our hope that the biomechanical knowledge of the carpal tunnel will improve the understanding and management of carpal tunnel syndrome.
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Affiliation(s)
- Zong-Ming Li
- Hand Research Laboratory, Departments of Orthopaedic Surgery and Biomedical Engineering, University of Arizona, Tucson, AZ, United States of America.
| | - David B Jordan
- Hand Research Laboratory, Departments of Orthopaedic Surgery and Biomedical Engineering, University of Arizona, Tucson, AZ, United States of America
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Yu L, Jia J, Lakshminarayanan K, Li Y, Gan Y, Yao Y. A finite element analysis of the carpal arch with various locations of carpal tunnel release. Front Surg 2023; 10:1134129. [PMID: 37206350 PMCID: PMC10189137 DOI: 10.3389/fsurg.2023.1134129] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Accepted: 04/13/2023] [Indexed: 05/21/2023] Open
Abstract
Objective The purpose of this study was to investigate the effects of the location of transverse carpal ligament (TCL) transection on the biomechanical property of the carpal arch structure. It was hypothesized that carpal tunnel release would lead to an increase of the carpal arch compliance (CAC) in a location-dependent manner. Methods A pseudo-3D finite element model of the volar carpal arch at the distal carpal tunnel was used to simulate arch area change under different intratunnel pressures (0-72 mmHg) after TCL transection at different locations along the transverse direction of the TCL. Results The CAC of the intact carpal arch was 0.092 mm2/mmHg, and the simulated transections ranging from 8 mm ulnarly to 8 mm radially from the center point of the TCL led to increased CACs that were 2.6-3.7 times of that of the intact carpal arch. The CACs after radial transections were greater than those ulnarly transected carpal arches. Conclusion The TCL transection in the radial region was biomechanically favorable in reducing carpal tunnel constraint for median nerve decompression.
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Affiliation(s)
- Lu Yu
- School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China
| | - Jingyi Jia
- School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China
| | - Kishor Lakshminarayanan
- Department of Sensors and Biomedical Engineering, Vellore Institute of Technology, Vellore, Tamil Nadu, India
| | - Yiming Li
- Orthopedic Department, Shanghai Ninth People’s Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Yaokai Gan
- Orthopedic Department, Shanghai Ninth People’s Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
- Correspondence: Yaokai Gan Yifei Yao
| | - Yifei Yao
- School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, China
- Correspondence: Yaokai Gan Yifei Yao
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Correlations between transverse carpal ligament thickness measured on ultrasound and severity of carpal tunnel syndrome on electromyography and disease duration. HAND SURGERY & REHABILITATION 2022; 41:377-383. [DOI: 10.1016/j.hansur.2022.02.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Revised: 02/09/2022] [Accepted: 02/18/2022] [Indexed: 11/24/2022]
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Simcox T, Seo L, Dunham K, Huang S, Petchprapa C, Wollstein R. Palmar Musculature: Does It Affect the Development of Carpal Tunnel Syndrome? A Pilot Study. J Wrist Surg 2021; 10:196-200. [PMID: 34109061 PMCID: PMC8169161 DOI: 10.1055/s-0040-1721437] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/03/2020] [Accepted: 10/28/2020] [Indexed: 10/22/2022]
Abstract
Background The etiology of carpal tunnel syndrome (CTS) is multifactorial. Static mechanical characteristics of CTS have been described, but dynamic (muscular) parameters remain obscure. We believe that musculature overlying the transverse carpal ligament may have an effect on carpal tunnel pressure and may explain the prevalence of CTS in manual workers. Questions/Purposes To utilize magnetic resonance imaging (MRI) imaging to estimate the amount of muscle crossing the area of the carpal tunnel and to compare these MRI measurements in patients with and without documented CTS. Methods A case-control study of wrist MRI scans between January 1, 2018, and December 1, 2019, was performed. Patients with a diagnosis of CTS were matched by age and gender with controls without a diagnosis of CTS. Axial MRI cuts at the level of the hook of the hamate were used to measure the thenar and hypothenar muscle depth overlying the carpal tunnel. Muscle depth was quantified in millimeters at three points: midcapitate, capitate-hamate border, capitate-trapezoid border. Average depth was calculated by dividing the cross-sectional area (CSA) by the transverse carpal ligament width. Statistical analysis included Student's t -test, chi-square test, and Pearson's correlation coefficient calculation. Results A total of 21 cases and 21 controls met the inclusion criteria for the study. There were no significant differences in demographics between case and control groups. The location and depth of the musculature crossing the carpal tunnel were highly variable in all areas evaluated. A significantly positive correlation was found between proximal median nerve CSA and muscle depth in the capitate-hamate area (correlation coefficient = 0.375; p = 0.014). CSA was not significantly associated with chart documented CTS. Conclusions We found large variability in our measurements. This likely reflects true anatomical variation. The significance of our findings depends on the location of the muscles and the line of pull and their effect on the mechanics of the transverse carpal ligament. Future research will focus on refining measurement methodology and understanding the mechanical effect of the muscular structure and insertions on carpal tunnel pressure. Level of Evidence This is a Level 3, case-control study.
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Affiliation(s)
- Trevor Simcox
- Departments of Orthopaedic Surgery and Radiology, School of Medicine, New York University, New York
| | - Lauren Seo
- Departments of Orthopaedic Surgery and Radiology, School of Medicine, New York University, New York
| | - Kevin Dunham
- Departments of Orthopaedic Surgery and Radiology, School of Medicine, New York University, New York
| | - Shengnan Huang
- Departments of Orthopaedic Surgery and Radiology, School of Medicine, New York University, New York
| | - Catherine Petchprapa
- Departments of Orthopaedic Surgery and Radiology, School of Medicine, New York University, New York
| | - Ronit Wollstein
- Departments of Orthopaedic Surgery and Radiology, School of Medicine, New York University, New York
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The Influence of Transverse Carpal Ligament Thickness on Treatment Decisions for Idiopathic Mild to Moderate Carpal Tunnel Syndrome. Ann Plast Surg 2021; 85:127-134. [PMID: 32332386 DOI: 10.1097/sap.0000000000002386] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE The main cause of carpal tunnel syndrome (CTS) is pathological changes in the flexor synovium, which is a known cause of pressure elevation in the carpal tunnel. The importance of the transverse carpal ligament (TCL) in the pathogenesis of CTS has hitherto been overlooked. However, the TCL significantly affects carpal biomechanics; the TCL is known to affect the carpal bone to a greater extent when intra carpal tunnel pressure is high. In addition, the effect of TCL properties on the progression course of idiopathic CTS is unknown.Therefore, we hypothesized that TCL thickness, measured using ultrasonography, would influence the results of conservative treatment for CTS patients with mild to moderate symptoms. We aimed to investigate the relationship between the ultrasound-measured TCL thickness and idiopathic carpal tunnel conservative treatment surgery rate. MATERIALS AND METHODS We analyzed the wrists of 127 patients with mild to moderate symptoms of CTS. The patients were diagnosed on the basis of electrophysiological assessment outcomes, median nerve cross-sectional area in the carpal tunnel, and clinical symptoms. The Boston carpal tunnel questionnaire score was also measured. Patients with a TCL thinner than 1.5 mm were classified into group A (n = 62), and those with a TCL thicker than 1.5 mm were classified into group B (n = 65). Patients with severe symptoms or other diseases were excluded. The patients were initially treated with night splinting after diagnosis. If symptoms were not ameliorated, steroid injection and surgical treatment were performed consecutively. The procedures were determined by a single surgeon. RESULTS The mean TCL thickness was 1.51 mm: 0.98 mm in group A and 2.28 mm in group B. The percentages of patients who underwent surgery were 43.0% in group A and 67.7% in group B. Group B was 1.77 times more likely to have surgery, and the interval between diagnosis and surgery and/or steroid injection was shorter. The TCL thickness in group B was also related to cross-sectional area and symptom duration. CONCLUSIONS Transverse carpal ligament thickness affects disease progression and may affect treatment efficacy, depending on the treatment method. Transverse carpal ligament thickness may be a criterion for deciding between surgical and conservative treatments based on a thickness threshold of 1.5 mm.
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