A sheep model of chronic cervical compressive myelopathy via an implantable wireless compression device

Zihe Li; Shuheng Zhai; Shanshan Liu; Chunhua Chen; Xinhu Guo; Panpan Hu; Ben Wang; Youyu Zhang; Feng Wei; Zhongjun Liu

doi:10.1007/s00586-022-07138-6

A sheep model of chronic cervical compressive myelopathy via an implantable wireless compression device

Eur Spine J. 2022 May;31(5):1219-1227. doi: 10.1007/s00586-022-07138-6. Epub 2022 Feb 22.

Authors

Zihe Li^#^{1

2

3}, Shuheng Zhai^#^{1

2

3}, Shanshan Liu^{1

2

3}, Chunhua Chen⁴, Xinhu Guo^{1

2

3}, Panpan Hu^{1

2

3}, Ben Wang^{1

2

3}, Youyu Zhang^{1

2

3}, Feng Wei^{5

6

7}, Zhongjun Liu^{1

2

3}

Affiliations

¹ Department of Orthopaedics, Peking University Third Hospital, 49 North Garden Road, Haidian District, Beijing, 100191, China.
² Engineering Research Center of Bone and Joint Precision Medicine, Ministry of Education, Beijing, China.
³ Beijing Key Laboratory of Spinal Disease Research, Beijing, China.
⁴ Department of Anatomy and Embryology, School of Basic Medical Sciences, Peking University Health Science Center, Beijing, China.
⁵ Department of Orthopaedics, Peking University Third Hospital, 49 North Garden Road, Haidian District, Beijing, 100191, China. weifeng@bjmu.edu.cn.
⁶ Engineering Research Center of Bone and Joint Precision Medicine, Ministry of Education, Beijing, China. weifeng@bjmu.edu.cn.
⁷ Beijing Key Laboratory of Spinal Disease Research, Beijing, China. weifeng@bjmu.edu.cn.

^# Contributed equally.

PMID: 35192070
DOI: 10.1007/s00586-022-07138-6

Abstract

Purpose: This study aimed to establish an animal model in which we can precisely displace the spinal cord and therefore mimic the chronic spinal compression of cervical spondylotic myelopathy.

Methods: In vivo intervertebral compression devices (IVCDs) connected with subcutaneous control modules (SCCMs) were implanted into the C2-3 intervertebral disk spaces of sheep and connected by Bluetooth to an in vitro control system. Sixteen sheep were divided into four groups: (Group A) control; (Group B) 10-week progressive compression, then held; (Group C) 20-week progressive compression, then held; and (Group D) 20-week progressive compression, then decompression. Electrophysiological analysis (latency and amplitude of the N1-P1-N2 wave in somatosensory evoked potentials, SEP), behavioral changes (Tarlov score), imaging test (encroachment ratio (ER) of intraspinal invasion determined by X-ray and CT scan), and histological examinations (hematoxylin and eosin, Nissl, and TUNEL staining) were performed to assess the efficacy of our model.

Results: Tarlov scores gradually decreased as compression increased with time and partially recovered after decompression. The Pearson correlation coefficient between ER and time was r = 0.993 (p < 0.001) in Group B at 10 weeks and Groups C and D at 20 weeks. And ER was negatively correlated with the Tarlov score (r = -0.878, p < 0.001). As compression progressed, the SEP latency was significantly extended (p < 0.001), and the amplitude significantly decreased (p < 0.001), while they were both partially restored after decompression. The number of abnormal motor neurons and TUNEL-positive cells increased significantly (p < 0.001) with compression.

Conclusion: Our implantable and wireless intervertebral compression model demonstrated outstanding controllability and reproducibility in simulating chronic cervical spinal cord compression in animals.

Keywords: Animal model; Cervical spinal cord; Cervical spondylotic myelopathy; Digital control; Implantable wireless compression device.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Animals
Cervical Vertebrae / diagnostic imaging
Cervical Vertebrae / pathology
Cervical Vertebrae / surgery
Evoked Potentials, Somatosensory / physiology
Humans
Reproducibility of Results
Sheep
Spinal Cord Compression* / etiology
Spinal Cord Compression* / pathology
Spinal Cord Compression* / surgery
Spinal Cord Diseases* / pathology
Spinal Osteophytosis*