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Shamli Oghli Y, Ashok A, Glener S, Ailes I, Syed M, Kang KC, Naghizadehkashani S, Fayed I, Mohamed FB, Talekar K, Krisa L, Wu C, Matias C, Alizadeh M. Multimodal functional imaging and clinical correlates of pain regions in chronic low-back pain patients treated with spinal cord stimulation: a pilot study. FRONTIERS IN NEUROIMAGING 2024; 3:1474060. [PMID: 39399386 PMCID: PMC11470492 DOI: 10.3389/fnimg.2024.1474060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/31/2024] [Accepted: 09/09/2024] [Indexed: 10/15/2024]
Abstract
Objective Spinal cord stimulation (SCS) is an invasive treatment option for patients suffering from chronic low-back pain (cLBP). It is an effective treatment that has been shown to reduce pain and increase the quality of life in patients. However, the activation of pain processing regions of cLBP patients receiving SCS has not been assessed using objective, quantitative functional imaging techniques. The purpose of the present study was to compare quantitative resting-state (rs)-fMRI and arterial spin labeling (ASL) measures between SCS patients and healthy controls and to correlate clinical measures with quantitative multimodal imaging indices in pain regions. Methods Multi-delay 3D GRASE pseudo-continuous ASL and rs-fMRI data were acquired from five patients post-SCS with cLBP and five healthy controls. Three ASL measures and four rs-fMRI measures were derived and normalized into MNI space and smoothed. Averaged values for each measure from a pain atlas were extracted and compared between patients and controls. Clinical pain scores assessing intensity, sensitization, and catastrophizing, as well as others assessing global pain effects (sleep quality, disability, anxiety, and depression), were obtained in patients and correlated with pain regions using linear regression analysis. Results Arterial transit time derived from ASL and several rs-fMRI measures were significantly different in patients in regions involved with sensation (primary somatosensory cortex and ventral posterolateral thalamus [VPL]), pain input (posterior short gyrus of the insula [PS]), cognition (dorsolateral prefrontal cortex [DLPC] and posterior cingulate cortex [PCC]), and fear/stress response (hippocampus and hypothalamus). Unidimensional pain rating and sensitization scores were linearly associated with PS, VPL, DLPC, PCC, and/or amygdala activity in cLBP patients. Conclusion The present results provide evidence that ASL and rs-fMRI can contrast functional activation in pain regions of cLBP patients receiving SCS and healthy subjects, and they can be associated with clinical pain evaluations as quantitative assessment tools.
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Affiliation(s)
- Yazan Shamli Oghli
- Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA, United States
- Jefferson Integrated Magnetic Resonance Imaging Center, Department of Radiology, Thomas Jefferson University, Philadelphia, PA, United States
- Department of Neurosurgery, Thomas Jefferson University, Philadelphia, PA, United States
| | - Arjun Ashok
- Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA, United States
- Jefferson Integrated Magnetic Resonance Imaging Center, Department of Radiology, Thomas Jefferson University, Philadelphia, PA, United States
- Department of Neurosurgery, Thomas Jefferson University, Philadelphia, PA, United States
| | - Steven Glener
- Department of Neurosurgery, Thomas Jefferson University, Philadelphia, PA, United States
| | - Isaiah Ailes
- Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA, United States
- Jefferson Integrated Magnetic Resonance Imaging Center, Department of Radiology, Thomas Jefferson University, Philadelphia, PA, United States
- Department of Neurosurgery, Thomas Jefferson University, Philadelphia, PA, United States
| | - Mashaal Syed
- Jefferson Integrated Magnetic Resonance Imaging Center, Department of Radiology, Thomas Jefferson University, Philadelphia, PA, United States
- Department of Neurosurgery, Thomas Jefferson University, Philadelphia, PA, United States
| | - Ki Chang Kang
- Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA, United States
- Jefferson Integrated Magnetic Resonance Imaging Center, Department of Radiology, Thomas Jefferson University, Philadelphia, PA, United States
- Department of Neurosurgery, Thomas Jefferson University, Philadelphia, PA, United States
| | - Sara Naghizadehkashani
- Jefferson Integrated Magnetic Resonance Imaging Center, Department of Radiology, Thomas Jefferson University, Philadelphia, PA, United States
| | - Islam Fayed
- Department of Neurosurgery, Cooper University Health Care, Camden, PA, United States
| | - Feroze B. Mohamed
- Jefferson Integrated Magnetic Resonance Imaging Center, Department of Radiology, Thomas Jefferson University, Philadelphia, PA, United States
| | - Kiran Talekar
- Jefferson Integrated Magnetic Resonance Imaging Center, Department of Radiology, Thomas Jefferson University, Philadelphia, PA, United States
| | - Laura Krisa
- Jefferson Integrated Magnetic Resonance Imaging Center, Department of Radiology, Thomas Jefferson University, Philadelphia, PA, United States
- Department of Occupational Therapy, Thomas Jefferson University, Philadelphia, PA, United States
| | - Chengyuan Wu
- Jefferson Integrated Magnetic Resonance Imaging Center, Department of Radiology, Thomas Jefferson University, Philadelphia, PA, United States
- Department of Neurosurgery, Thomas Jefferson University, Philadelphia, PA, United States
| | - Caio Matias
- Department of Neurosurgery, Thomas Jefferson University, Philadelphia, PA, United States
| | - Mahdi Alizadeh
- Jefferson Integrated Magnetic Resonance Imaging Center, Department of Radiology, Thomas Jefferson University, Philadelphia, PA, United States
- Department of Neurosurgery, Thomas Jefferson University, Philadelphia, PA, United States
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Increased substance P and synaptic remodeling occur in the trigeminal sensory system with sustained osteoarthritic temporomandibular joint sensitivity. Pain Rep 2021; 6:e911. [PMID: 33977183 PMCID: PMC8104398 DOI: 10.1097/pr9.0000000000000911] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2020] [Revised: 11/24/2020] [Accepted: 12/18/2020] [Indexed: 12/15/2022] Open
Abstract
Supplemental Digital Content is Available in the Text. Increased substance P and a loss of inhibitory synapses occurs within the brain's trigeminal sensory system with persistent, but not transient, temporomandibular joint sensitivity. Introduction: Temporomandibular joint (TMJ) pain is among the most prevalent musculoskeletal conditions and can result from atypical joint loading. Although TMJ pain is typically self-resolving, 15% of patients develop chronic TMJ pain that is recalcitrant to therapy and may be attributed to changes in pain processing centers. Although TMJ overloading induces pain and osteoarthritis, whether neuronal modifications in the trigeminal sensory system contribute to persistent TMJ pain is unknown. Objective: This study investigates changes in excitatory neuropeptides and synaptic transmission proteins in cases of transient and persistent TMJ sensitivity in a rat model. Methods: Rats underwent repeated jaw loading that produces transient (2N-load) or persistent (3.5N-load) sensitivity. In both groups, immunolabeling was used to assess substance P in the spinal trigeminal nucleus caudalis (Sp5C) and glutamate transporter 1 in the ventroposteriomedial thalamus early after loading. Synaptosomal Western blots were used to measure synaptic proteins in the caudal medulla and thalamus at a later time after loading. Results: Substance P increases transiently in the Sp5C early after loading that induces persistent sensitivity. However, glutamate transporter 1 is unchanged in the ventroposteriomedial thalamus. At a later time, synaptosomal Western blots show loss of the presynaptic tethering protein, synapsin, and the inhibitory scaffolding protein, gephyrin, in the thalamus with persistent, but not transient, sensitivity. No changes are identified in synapsin, phosphorylated synapsin, homer, or gephyrin in the caudal medulla. Conclusions: Substance P in the Sp5C and later loss of inhibitory synapses in the thalamus likely contribute to, or indicate, persistent TMJ pain.
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Quindlen-Hotek JC, Kent AR, De Anda P, Kartha S, Benison AM, Winkelstein BA. Changes in Neuronal Activity in the Anterior Cingulate Cortex and Primary Somatosensory Cortex With Nonlinear Burst and Tonic Spinal Cord Stimulation. Neuromodulation 2020; 23:594-604. [PMID: 32027444 DOI: 10.1111/ner.13116] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Revised: 11/20/2019] [Accepted: 01/02/2020] [Indexed: 12/14/2022]
Abstract
INTRODUCTION Although nonlinear burst and tonic SCS are believed to treat neuropathic pain via distinct pain pathways, the effectiveness of these modalities on brain activity in vivo has not been investigated. This study compared neuronal firing patterns in the brain after nonlinear burst and tonic SCS in a rat model of painful radiculopathy. METHODS Neuronal activity was recorded in the ACC or S1 before and after nonlinear burst or tonic SCS on day 7 following painful cervical nerve root compression (NRC) or sham surgery. The amplitude of nonlinear burst SCS was set at 60% and 90% motor threshold to investigate the effect of lower amplitude SCS on brain activity. Neuronal activity was recorded during and immediately following light brush and noxious pinch of the paw. Change in neuron firing was measured as the percent change in spikes post-SCS relative to pre-SCS baseline. RESULTS ACC activity decreases during brush after 60% nonlinear burst compared to tonic (p < 0.05) after NRC and compared to 90% nonlinear burst (p < 0.04) and pre-SCS baseline (p < 0.03) after sham. ACC neuron activity decreases (p < 0.01) during pinch after 60% and 90% nonlinear burst compared to tonic for NRC. The 60% of nonlinear burst decreases (p < 0.02) ACC firing during pinch in both groups compared to baseline. In NRC S1 neurons, tonic SCS decreases (p < 0.01) firing from baseline during light brush; 60% nonlinear burst decreases (p < 0.01) firing from baseline during brush and pinch. CONCLUSIONS Nonlinear burst SCS reduces firing in the ACC from a painful stimulus; a lower amplitude nonlinear burst appears to have the greatest effect. Tonic and nonlinear burst SCS may have comparable effects in S1.
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Affiliation(s)
| | | | - Patrisia De Anda
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA
| | - Sonia Kartha
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA
| | | | - Beth A Winkelstein
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA, USA.,Department of Neurosurgery, University of Pennsylvania, Philadelphia, PA, USA
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Regional Hyperexcitability and Chronic Neuropathic Pain Following Spinal Cord Injury. Cell Mol Neurobiol 2020; 40:861-878. [PMID: 31955281 DOI: 10.1007/s10571-020-00785-7] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Accepted: 01/02/2020] [Indexed: 12/15/2022]
Abstract
Spinal cord injury (SCI) causes maladaptive changes to nociceptive synaptic circuits within the injured spinal cord. Changes also occur at remote regions including the brain stem, limbic system, cortex, and dorsal root ganglia. These maladaptive nociceptive synaptic circuits frequently cause neuronal hyperexcitability in the entire nervous system and enhance nociceptive transmission, resulting in chronic central neuropathic pain following SCI. The underlying mechanism of chronic neuropathic pain depends on the neuroanatomical structures and electrochemical communication between pre- and postsynaptic neuronal membranes, and propagation of synaptic transmission in the ascending pain pathways. In the nervous system, neurons are the only cell type that transmits nociceptive signals from peripheral receptors to supraspinal systems due to their neuroanatomical and electrophysiological properties. However, the entire range of nociceptive signaling is not mediated by any single neuron. Current literature describes regional studies of electrophysiological or neurochemical mechanisms for enhanced nociceptive transmission post-SCI, but few studies report the electrophysiological, neurochemical, and neuroanatomical changes across the entire nervous system following a regional SCI. We, along with others, have continuously described the enhanced nociceptive transmission in the spinal dorsal horn, brain stem, thalamus, and cortex in SCI-induced chronic central neuropathic pain condition, respectively. Thus, this review summarizes the current understanding of SCI-induced neuronal hyperexcitability and maladaptive nociceptive transmission in the entire nervous system that contributes to chronic central neuropathic pain.
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Kent AR, Weisshaar CL, Venkatesan L, Winkelstein BA. Burst & High-Frequency Spinal Cord Stimulation Differentially Effect Spinal Neuronal Activity After Radiculopathy. Ann Biomed Eng 2019; 48:112-120. [DOI: 10.1007/s10439-019-02336-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2019] [Accepted: 07/30/2019] [Indexed: 01/21/2023]
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Sperry MM, Ita ME, Kartha S, Zhang S, Yu YH, Winkelstein B. The Interface of Mechanics and Nociception in Joint Pathophysiology: Insights From the Facet and Temporomandibular Joints. J Biomech Eng 2017; 139:2597611. [PMID: 28056123 DOI: 10.1115/1.4035647] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2016] [Indexed: 12/16/2022]
Abstract
Chronic joint pain is a widespread problem that frequently occurs with aging and trauma. Pain occurs most often in synovial joints, the body's load bearing joints. The mechanical and molecular mechanisms contributing to synovial joint pain are reviewed using two examples, the cervical spinal facet joints and the temporomandibular joint (TMJ). Although much work has focused on the macroscale mechanics of joints in health and disease, the combined influence of tissue mechanics, molecular processes, and nociception in joint pain has only recently become a focus. Trauma and repeated loading can induce structural and biochemical changes in joints, altering their microenvironment and modifying the biomechanics of their constitutive tissues, which themselves are innervated. Peripheral pain sensors can become activated in response to changes in the joint microenvironment and relay pain signals to the spinal cord and brain where pain is processed and perceived. In some cases, pain circuitry is permanently changed, which may be a potential mechanism for sustained joint pain. However, it is most likely that alterations in both the joint microenvironment and the central nervous system (CNS) contribute to chronic pain. As such, the challenge of treating joint pain and degeneration is temporally and spatially complicated. This review summarizes anatomy, physiology, and pathophysiology of these joints and the sensory pain relays. Pain pathways are postulated to be sensitized by many factors, including degeneration and biochemical priming, with effects on thresholds for mechanical injury and/or dysfunction. Initiators of joint pain are discussed in the context of clinical challenges including the diagnosis and treatment of pain.
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Affiliation(s)
- Megan M Sperry
- Department of Bioengineering, University of Pennsylvania, 240 Skirkanich Hall, 210 S. 33rd Street, Philadelphia, PA 19104-6321 e-mail:
| | - Meagan E Ita
- Department of Bioengineering, University of Pennsylvania, 240 Skirkanich Hall, 210 S. 33rd Street, Philadelphia, PA 19104-6321 e-mail:
| | - Sonia Kartha
- Department of Bioengineering, University of Pennsylvania, 240 Skirkanich Hall, 210 S. 33rd Street, Philadelphia, PA 19104-6321 e-mail:
| | - Sijia Zhang
- Department of Bioengineering, University of Pennsylvania, 240 Skirkanich Hall, 210 S. 33rd Street, Philadelphia, PA 19104-6321 e-mail:
| | - Ya-Hsin Yu
- Department of Endodontics, School of Dental Medicine, University of Pennsylvania, 240 Skirkanich Hall, 210 S. 33rd Street, Philadelphia, PA 19104-6321 e-mail:
| | - Beth Winkelstein
- Departments of Bioengineering and Neurosurgery, University of Pennsylvania, 240 Skirkanich Hall, 210 S. 33rd Street, Philadelphia, PA 19104-6321 e-mail:
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Differential effect of motor cortex stimulation on unit activities in the ventral posterior lateral thalamus in cats. Pain 2017; 159:157-167. [DOI: 10.1097/j.pain.0000000000001080] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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Weisshaar CL, Kras JV, Pall PS, Kartha S, Winkelstein BA. Ablation of IB4 non-peptidergic afferents in the rat facet joint prevents injury-induced pain and thalamic hyperexcitability via supraspinal glutamate transporters. Neurosci Lett 2017; 655:82-89. [PMID: 28689926 DOI: 10.1016/j.neulet.2017.07.006] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2017] [Revised: 07/04/2017] [Accepted: 07/05/2017] [Indexed: 12/12/2022]
Abstract
The facet joint is a common source of neck pain, particularly after excessive stretch of its capsular ligament. Peptidergic afferents have been shown to have an important role in the development and maintenance of mechanical hyperalgesia, dysregulated nociceptive signaling, and spinal hyperexcitability that develop after mechanical injury to the facet joint. However, the role of non-peptidergic isolectin-B4 (IB4) cells in mediating joint pain is unknown. Isolectin-B4 saporin (IB4-SAP) was injected into the facet joint to ablate non-peptidergic cells, and the facet joint later underwent a ligament stretch known to induce pain. Behavioral sensitivity, thalamic glutamate transporter expression, and thalamic hyperexcitability were evaluated up to and at day 7. Administering IB4-SAP prior to a painful injury prevented the development of mechanical hyperalgesia that is typically present. Intra-articular IB4-SAP also prevented the upregulation of the glutamate transporters GLT-1 and EAAC1 in the ventral posterolateral nucleus of the thalamus and reduced thalamic neuronal hyperexcitability at day 7. These findings suggest that a painful facet injury induces changes extending to supraspinal structures and that IB4-positive afferents in the facet joint may be critical for the development and maintenance of sensitization in the thalamus after a painful facet joint injury.
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Affiliation(s)
- Christine L Weisshaar
- Department of Bioengineering, University of Pennsylvania, 240 Skirkanich Hall, 210 S. 33rd St Philadelphia, PA 19104, USA
| | - Jeffrey V Kras
- Department of Bioengineering, University of Pennsylvania, 240 Skirkanich Hall, 210 S. 33rd St Philadelphia, PA 19104, USA
| | - Parul S Pall
- Department of Bioengineering, University of Pennsylvania, 240 Skirkanich Hall, 210 S. 33rd St Philadelphia, PA 19104, USA
| | - Sonia Kartha
- Department of Bioengineering, University of Pennsylvania, 240 Skirkanich Hall, 210 S. 33rd St Philadelphia, PA 19104, USA
| | - Beth A Winkelstein
- Department of Bioengineering, University of Pennsylvania, 240 Skirkanich Hall, 210 S. 33rd St Philadelphia, PA 19104, USA; Department of Neurosurgery, University of Pennsylvania, 105 Hayden Hall, 3320 Smith Walk, Philadelphia, PA 19104, USA.
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Gee LE, Walling I, Ramirez-Zamora A, Shin DS, Pilitsis JG. Subthalamic deep brain stimulation alters neuronal firing in canonical pain nuclei in a 6-hydroxydopamine lesioned rat model of Parkinson's disease. Exp Neurol 2016; 283:298-307. [PMID: 27373204 DOI: 10.1016/j.expneurol.2016.06.031] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2016] [Revised: 06/18/2016] [Accepted: 06/28/2016] [Indexed: 01/13/2023]
Abstract
INTRODUCTION Chronic pain is one of the most common non-motor symptoms of Parkinson's disease (PD) affecting up to 85% of patients. Previous studies have established that reduced mechanical and thermal thresholds occur in both idiopathic PD patients and animal models of PD, suggesting that changes may occur in sensory processing circuits. Improvements in sensory thresholds are achieved using subthalamic nucleus (STN) deep brain stimulation (DBS), however the mechanism by which this occurs remains unresolved. MATERIALS AND METHODS We examined unilateral medial forebrain bundle 6-hydroxydopamine (6OHDA) rat model of PD to determine whether STN DBS alters neuronal firing rates in brain areas involved in ascending and descending pain processing. Specifically, single unit in vivo recordings were conducted in the anterior cingulate cortex (ACC), the periaqueductal grey (PAG), and the ventral posteriolateral nucleus of the thalamus (VPL), before, during and after stimulation was applied to the STN at 50 or 150Hz. RESULTS Sham and 6OHDA lesioned animals have similar neuronal firing activity in the VPL, ACC and PAG before stimulation was applied (p>0.05). In 6OHDA lesioned rats, both low frequency stimulation (LFS) (p<0.01) and high frequency stimulation (HFS) (p<0.05) attenuated firing frequency in the ACC. In shams, only LFS decreased firing frequency. A subset of neurons in the PAG was significantly attenuated in both sham and 6OHDA lesioned animals during HFS and LFS (p<0.05), while another subset of PAG neuronal activity significantly increased in 6OHDA lesioned rats during HFS (p<0.05). Finally, low or high frequency STN DBS did not alter neuronal firing frequencies in the VPL. CONCLUSIONS Our results suggest that STN DBS alters neuronal firing in descending pain circuits. We hypothesize that STN DBS attenuates excitatory projections from the ACC to the PAG in 6OHDA lesioned rats. Following this, neurons in the PAG respond by either increasing (during HFS only) or decreasing (during both LFS and HFS), which may modulate descending facilitation or inhibition at the level of the spinal cord. Future work should address specific neuronal changes in the ACC and PAG that occur in a freely moving parkinsonian animal during a pain stimulus treated with STN DBS.
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Affiliation(s)
- Lucy E Gee
- Department of Neuroscience and Experimental Therapeutics, Albany Medical College, Albany, NY, United States; Department of Neurosurgery, Albany Medical Center, Albany, NY, United States
| | - Ian Walling
- Department of Neuroscience and Experimental Therapeutics, Albany Medical College, Albany, NY, United States; Department of Neurosurgery, Albany Medical Center, Albany, NY, United States
| | | | - Damian S Shin
- Department of Neuroscience and Experimental Therapeutics, Albany Medical College, Albany, NY, United States
| | - Julie G Pilitsis
- Department of Neuroscience and Experimental Therapeutics, Albany Medical College, Albany, NY, United States; Department of Neurosurgery, Albany Medical Center, Albany, NY, United States.
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Relevant Anatomic and Morphological Measurements of the Rat Spine: Considerations for Rodent Models of Human Spine Trauma. Spine (Phila Pa 1976) 2015; 40:E1084-92. [PMID: 26731709 DOI: 10.1097/brs.0000000000001021] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
STUDY DESIGN Basic science study measuring anatomical features of the cervical and lumbar spine in rat with normalized comparison with the human. OBJECTIVE The goal of this study is to comprehensively compare the rat and human cervical and lumbar spines to investigate whether the rat is an appropriate model for spine biomechanics investigations. SUMMARY OF BACKGROUND DATA Animal models have been used for a long time to investigate the effects of trauma, degenerative changes, and mechanical loading on the structure and function of the spine. Comparative studies have reported some mechanical properties and/or anatomical dimensions of the spine to be similar between various species. However, those studies are largely limited to the lumbar spine, and a comprehensive comparison of the rat and human spines is lacking. METHODS Spines were harvested from male Holtzman rats (n = 5) and were scanned using micro- computed tomography and digitally rendered in 3 dimensions to quantify the spinal bony anatomy, including the lateral width and anteroposterior depth of the vertebra, vertebral body, and spinal canal, as well as the vertebral body and intervertebral disc heights. Normalized measurements of the vertebra, vertebral body, and spinal canal of the rat were computed and compared with corresponding measurements from the literature for the human in the cervical and lumbar spinal regions. RESULTS The vertebral dimensions of the rat spine vary more between spinal levels than in humans. Rat vertebrae are more slender than human vertebrae, but the width-to-depth axial aspect ratios are very similar in both species in both the cervical and lumbar regions, especially for the spinal canal. CONCLUSION The similar spinal morphology in the axial plane between rats and humans supports using the rat spine as an appropriate surrogate for modeling axial and shear loading of the human spine.
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