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Wilcox M, Dos Santos Canas L, Hargunani R, Tidswell T, Brown H, Modat M, Phillips JB, Ourselin S, Quick T. Volumetric MRI is a promising outcome measure of muscle reinnervation. Sci Rep 2021; 11:22433. [PMID: 34789795 PMCID: PMC8599480 DOI: 10.1038/s41598-021-01342-y] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Accepted: 10/18/2021] [Indexed: 11/09/2022] Open
Abstract
The development of outcome measures that can track the recovery of reinnervated muscle would benefit the clinical investigation of new therapies which hope to enhance peripheral nerve repair. The primary objective of this study was to assess the validity of volumetric Magnetic Resonance Imaging (MRI) as an outcome measure of muscle reinnervation by testing its reproducibility, responsiveness and relationship with clinical indices of muscular function. Over a 3-year period 25 patients who underwent nerve transfer to reinnervate elbow flexor muscles were assessed using intramuscular electromyography (EMG) and MRI (median post-operative assessment time of 258 days, ranging from 86 days pre-operatively to 1698 days post- operatively). Muscle power (Medical Research Council (MRC) grade) and Stanmore Percentage of Normal Elbow Assessment (SPONEA) assessment was also recorded for all patients. Sub-analysis of peak volitional force (PVF), muscular fatigue and co-contraction was performed in those patients with MRC > 3. The responsiveness of each parameter was compared using Pearson or Spearman correlation. A Hierarchical Gaussian Process (HGP) was implemented to determine the ability of volumetric MRI measurements to predict the recovery of muscular function. Reinnervated muscle volume per unit Body Mass Index (BMI) demonstrated good responsiveness (R2 = 0.73, p < 0.001). Using the temporal and muscle volume per unit BMI data, a HGP model was able to predict MRC grade and SPONEA with a mean absolute error (MAE) of 0.73 and 1.7 respectively. Muscle volume per unit BMI demonstrated moderate to good positive correlations with patient reported impairments of reinnervated muscle; co- contraction (R2 = 0.63, p = 0.02) and muscle fatigue (R2 = 0.64, p = 0.04). In summary, volumetric MRI analysis of reinnervated muscle is highly reproducible, responsive to post-operative time and demonstrates correlation with clinical indices of muscle function. This encourages the view that volumetric MRI is a promising outcome measure for muscle reinnervation which will drive advancements in motor recovery therapy.
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Affiliation(s)
- Matthew Wilcox
- Peripheral Nerve Injury Research Unit, Royal National Orthopaedic Hospital, Stanmore, UK. .,UCL Centre for Nerve Engineering, University College London, London, UK. .,Department of Pharmacology, UCL School of Pharmacy, University College London, London, UK. .,University College London Medical School, London, UK.
| | | | - Rikin Hargunani
- Department of Radiology, Royal National Orthopaedic Hospital, Stanmore, UK
| | - Tom Tidswell
- Department of Clinical Neurophysiology, Royal Free Hospital, London, UK
| | - Hazel Brown
- Peripheral Nerve Injury Research Unit, Royal National Orthopaedic Hospital, Stanmore, UK.,UCL Centre for Nerve Engineering, University College London, London, UK
| | - Marc Modat
- Biomedical Engineering and Imaging Sciences, King's College London, London, UK
| | - James B Phillips
- UCL Centre for Nerve Engineering, University College London, London, UK.,Department of Pharmacology, UCL School of Pharmacy, University College London, London, UK
| | - Sebastien Ourselin
- Biomedical Engineering and Imaging Sciences, King's College London, London, UK
| | - Tom Quick
- Peripheral Nerve Injury Research Unit, Royal National Orthopaedic Hospital, Stanmore, UK.,UCL Centre for Nerve Engineering, University College London, London, UK
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Rasouli B, Pederson K, Wilkinson MF, Zarrabian M. Peripheral leg ischemia detected via intraoperative neurophysiological monitoring during a multilevel complex anterior and posterior operation. J Surg Case Rep 2020; 2020:rjaa049. [PMID: 32440330 PMCID: PMC7232934 DOI: 10.1093/jscr/rjaa049] [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: 02/08/2020] [Accepted: 02/26/2020] [Indexed: 11/13/2022] Open
Abstract
Intraoperative neurophysiologic monitoring is a technique utilized during spinal operations to minimize sensory and motor function morbidity. We herein report a case of a 73-year-old female with renal cell carcinoma and metastatic involvement of the cervical and thoracic spine, who underwent a multilevel complex anterior and posterior operation. Neurophysiological monitoring was able to localize the lower limb ischemia utilizing somatosensory evoked potentials. This prompted intraoperative investigation of the peripheral ischemia, and the patient was found to have an Angio-Seal device embolus in the right popliteal artery that dislodged from the right femoral artery.
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Affiliation(s)
- Bobak Rasouli
- School of Medicine, St. George's University of London, Nicosia, Cyprus
| | | | | | - Mohammad Zarrabian
- Division of Orthopaedic Surgery, University of Manitoba, Winnipeg, Canada
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Characterising cellular and molecular features of human peripheral nerve degeneration. Acta Neuropathol Commun 2020; 8:51. [PMID: 32303273 PMCID: PMC7164159 DOI: 10.1186/s40478-020-00921-w] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2019] [Accepted: 03/26/2020] [Indexed: 12/23/2022] Open
Abstract
Nerve regeneration is a key biological process in those recovering from neural trauma. From animal models it is known that the regenerative capacity of the peripheral nervous system (PNS) relies heavily on the remarkable ability of Schwann cells to undergo a phenotypic shift from a myelinating phenotype to one that is supportive of neural regeneration. In rodents, a great deal is known about the molecules that control this process, such as the transcription factors c-Jun and early growth response protein 2 (EGR2/KROX20), or mark the cells and cellular changes involved, including SOX10 and P75 neurotrophin receptor (p75NTR). However, ethical and practical challenges associated with studying human nerve injury have meant that little is known about human nerve regeneration.The present study addresses this issue, analysing 34 denervated and five healthy nerve samples from 27 patients retrieved during reconstructive nerve procedures. Using immunohistochemistry and Real-Time quantitative Polymerase Chain Reaction (RT-qPCR), the expression of SOX10, c-Jun, p75NTR and EGR2 was assessed in denervated samples and compared to healthy nerve. Nonparametric smoothing linear regression was implemented to better visualise trends in the expression of these markers across denervated samples.It was found, first, that two major genes associated with repair Schwann cells in rodents, c-Jun and p75NTR, are also up-regulated in acutely injured human nerves, while the myelin associated transcription factor EGR2 is down-regulated, observations that encourage the view that rodent models are relevant for learning about human nerve injury. Second, as in rodents, the expression of c-Jun and p75NTR declines during long-term denervation. In rodents, diminishing c-Jun and p75NTR levels mark the general deterioration of repair cells during chronic denervation, a process thought to be a major obstacle to effective nerve repair. The down-regulation of c-Jun and p75NTR reported here provides the first molecular evidence that also in humans, repair cells deteriorate during chronic denervation.
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Wilcox M, Quick TJ, Phillips JB. The Effects of Surgical Antiseptics and Time Delays on RNA Isolated From Human and Rodent Peripheral Nerves. Front Cell Neurosci 2019; 13:189. [PMID: 31178696 PMCID: PMC6538796 DOI: 10.3389/fncel.2019.00189] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Accepted: 04/12/2019] [Indexed: 01/25/2023] Open
Abstract
Peripheral Nerve Injury (PNI) is common following blunt or penetrating trauma with an estimated prevalence of 2% among the trauma population. The resulting economic and societal impacts are significant. Nerve regeneration is a key biological process in those recovering from neural trauma. Real Time-quantitative Polymerase Chain Reaction (RT-qPCR) and RNA sequencing (RNA seq) are investigative methods that are often deployed by researchers to characterize the cellular and molecular mechanisms that underpin this process. However, the ethical and practical challenges associated with studying human nerve injury have meant that studies of nerve injury have largely been limited to rodent models of renervation. In some circumstances it is possible to liberate human nerve tissue for study, for example during reconstructive nerve repair. This complex surgical environment affords numerous challenges for optimizing the yield of RNA in sufficient quantity and quality for downstream RT-qPCR and/or RNA seq applications. This study characterized the effect of: (1) Time delays between surgical liberation and cryopreservation and (2) contact with antiseptic surgical reagents, on the quantity and quality of RNA isolated from human and rodent nerve samples. It was found that time delays of greater than 3 min between surgical liberation and cryopreservation of human nerve samples significantly decreased RNA concentrations to be sub-optimal for downstream RT-qPCR/RNA seq applications (<5 ng/μl). Minimizing the exposure of human nerve samples to antiseptic surgical reagents significantly increased yield of RNA isolated from samples. The detrimental effect of antiseptic reagents on RNA yield was further confirmed in a rodent model where RNA yield was 8.3-fold lower compared to non-exposed samples. In summary, this study has shown that changes to the surgical tissue collection protocol can have significant effects on the yield of RNA isolated from nerve samples. This will enable the optimisation of protocols in future studies, facilitating characterisation of the cellular and molecular mechanisms that underpin the regenerative capacity of the human peripheral nervous system.
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Affiliation(s)
- Matthew Wilcox
- Peripheral Nerve Injury Research Unit, Royal National Orthopaedic Hospital, Stanmore, United Kingdom.,Department of Pharmacology, UCL School of Pharmacy, University College London, London, United Kingdom.,UCL Centre for Nerve Engineering, University College London, London, United Kingdom
| | - Tom J Quick
- Peripheral Nerve Injury Research Unit, Royal National Orthopaedic Hospital, Stanmore, United Kingdom.,Department of Pharmacology, UCL School of Pharmacy, University College London, London, United Kingdom.,UCL Centre for Nerve Engineering, University College London, London, United Kingdom
| | - James B Phillips
- Department of Pharmacology, UCL School of Pharmacy, University College London, London, United Kingdom.,UCL Centre for Nerve Engineering, University College London, London, United Kingdom
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Saponaro-González Á, Pérez-Lorensu PJ. Novel approach to continuous neurophysiological monitoring during surgery of peripheral nerve tumors. Surg Neurol Int 2017; 8:184. [PMID: 28868196 PMCID: PMC5569406 DOI: 10.4103/sni.sni_414_16] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2016] [Accepted: 06/07/2017] [Indexed: 11/15/2022] Open
Abstract
Background: Intraoperative neurophysiological monitoring (IONM) with nerve action potential (NAP) can be useful during peripheral nerve surgery. However, current methodologies are not optimized for continuous recording of the NAP. The use of newer electrodes may make it possible to more conveniently obtain continuous recordings of the NAP during surgery. Methods: After localizing the nerve of interest and dissecting it from the adjacent soft tissue, two APS® (Automatic Periodic Stimulation) electrodes, originally designed for stimulation of the vagus nerve during thyroid surgery, are placed on the nerve on either sides of the tumor for stimulation and recording using two subdermal electroencephalogram (EEG) needles as anode and reference, respectively. Both monopolar and bipolar recordings can be used as appropriate. Anesthesia regime comprised sevoflurane or total intravenous anesthesia (TIVA). No muscle relaxant after intubation, local anesthesia, or blood pressure cuff is used during the surgery. Results: Twelve patients (6 male, 6 female) with peripheral nerve tumors (motor, sensitive, or mixed nerves) or tumors affecting the peripheral nerves were monitored in our center since 2014 (mean age: 50 years; 28–79). In 10 patients, the NAP was monitored without experiencing any changes from the beginning till the end of the surgery; in these patients, no postoperative deficit was adverted. In the last 2 patients, who departed from a complete neurological deficit, no NAP was recorded at the baseline or during the surgery, and they did not experience any neurological improvement. Conclusion: The vagus nerve stimulation electrodes open new possibilities in peripheral nerve IONM. We have used them for continuous monitoring without additional problems with the traditional probes.
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Affiliation(s)
- Ángel Saponaro-González
- Intraoperative Neurophysiological Monitoring Unit, Hospital Universitario de Canarias, San Cristobal de la Laguna, Santa Cruz de Tenerife, Spain
| | - Pedro Javier Pérez-Lorensu
- Intraoperative Neurophysiological Monitoring Unit, Hospital Universitario de Canarias, San Cristobal de la Laguna, Santa Cruz de Tenerife, Spain
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