scholarly journals Biomechanical study of the C5–C8 cervical extraforaminal ligaments

2020 ◽  
Vol 15 (1) ◽  
Author(s):  
Qinghao Zhao ◽  
Yemei Yang ◽  
Penghuan Wu ◽  
Chengyan Huang ◽  
Rusen Zhang ◽  
...  
Keyword(s):  
Nerve Root ◽  
Bone Structure ◽  
Spinal Nerve ◽  
Biomechanical Study ◽  
Rate Of Change ◽  
Intervertebral Foramen ◽  
Nerve Roots ◽  
Load Range ◽  
Paravertebral Muscles ◽  
Intervertebral Foramina

Abstract Background The anatomical distribution of the extraforaminal ligaments in the cervical intervertebral foramina has been well studied. However, detailed descriptions of the biomechanical characteristics of these ligaments are lacking. Methods The paravertebral muscles were dissected, and the extraforaminal ligaments and nerve roots were identified. The C5 and C7 or C6 and C8 cervical nerve roots on both sides were randomly selected, and a window was opened on the vertebral lamina to expose the posterior spinal nerve root segments. Five needles were placed on the nerve root and the bone structure around the intervertebral foramen; the distal end of the nerve root was then tied with silk thread, and the weights were connected across the pulley. A weight load was gradually applied to the nerve root (50 g/time, 60 times in total). At the end of the experiment, segments of the extraforaminal ligaments were selectively cut off to compare the changes in nerve root displacement. Results The displacement of the C5, C6, C7, and C8 nerve roots increases with an increasing traction load, and the rate of change of nerve root displacement in the intervertebral foramen is smaller than that in the nerve root on the outside area (p < 0.05). Extraforaminal ligaments can absorb part of the pulling load of the nerve root; the C5 nerve root has the largest load range. Conclusions Cervical extraforaminal ligaments can disperse the tension load on the nerve root and play a role in protecting the nerve root. The protective effect of the C5 nerve root was the strongest, and this may anatomically explain why the C5 nerve roots are less prone to simple avulsion.

scholarly journals Biomechanical Study of the C5-C8 Cervical Extraforaminal Ligaments

2020 ◽  
Author(s):  
Qinghao Zhao ◽  
Yemei Yang ◽  
Penghuan Wu ◽  
Chengyan Huang ◽  
Rusen Zhang ◽  
...  
Keyword(s):  
Nerve Root ◽  
Bone Structure ◽  
Spinal Nerve ◽  
Biomechanical Study ◽  
Rate Of Change ◽  
Intervertebral Foramen ◽  
Nerve Roots ◽  
Load Range ◽  
Paravertebral Muscles ◽  
Intervertebral Foramina

Abstract Background:The anatomical distribution of the extraforaminal ligaments in the cervical intervertebral foramina has been well studied. However, detailed descriptions of the biomechanical characteristics of these ligaments are lacking.Methods: The paravertebral muscles were dissected, and the extraforaminal ligaments and nerve roots were identified. The C5 and C7 or C6 and C8 cervical nerve roots on both sides were randomly selected, and a window was opened on the vertebral lamina to expose the posterior spinal nerve root segments. Five needles were placed on the nerve root and the bone structure around the intervertebral foramen; the distal end of the nerve root was then tied with silk thread, and the weights were connected across the pulley. A weight load was gradually applied to the nerve root (50 g/ time, 60 times in total). At the end of the experiment, segments of the extraforaminal ligaments were selectively cut off to compare the changes in nerve root displacement.Results: The displacement of the C5, C6, C7, C8 nerve roots increases with an increasing traction load, and the rate of change of nerve root displacement in the intervertebral foramen is smaller than that in the nerve root on the outside area (p <0.05). Extraforaminal ligaments can absorb part of the pulling load of the nerve root; the C5 nerve root has the largest load range.Conclusions: Cervical extraforaminal ligaments can disperse the tension load on the nerve root and play a role in protecting the nerve root. The protective effect of the C5 nerve root was the strongest, and this may anatomically explain why the C5 nerve roots are less prone to simple avulsion.

scholarly journals Biomechanical Study of the C5-C8 Cervical Extraforaminal Ligaments

2020 ◽  
Author(s):  
Qinghao Zhao ◽  
Yemei Yang ◽  
Penghuan Wu ◽  
Chengyan Huang ◽  
Rusen Zhang ◽  
...  
Keyword(s):  
Nerve Root ◽  
Bone Structure ◽  
Spinal Nerve ◽  
Biomechanical Study ◽  
Rate Of Change ◽  
Intervertebral Foramen ◽  
Nerve Roots ◽  
Load Range ◽  
Paravertebral Muscles ◽  
Intervertebral Foramina

Abstract Background The anatomical distribution of the extraforaminal ligaments in the cervical intervertebral foramina has been well studied. However, detailed descriptions of the biomechanical characteristics of these ligaments are lacking. Methods The paravertebral muscles were dissected, and the extraforaminal ligaments and nerve roots were identified. The C5 and C7 or C6 and C8 cervical nerve roots on both sides were randomly selected, and a window was opened on the vertebral lamina to expose the posterior spinal nerve root segments. Five needles were placed on the nerve root and the bone structure around the intervertebral foramen; the distal end of the nerve root was then tied with silk thread, and the weights were connected across the pulley. A weight load was gradually applied to the nerve root (50 g/ time, 60 times in total). At the end of the experiment, segments of the extraforaminal ligaments were selectively cut off to compare the changes in nerve root displacement. Results The displacement of the C5, C6, C7, C8 nerve roots increases with an increasing traction load, and the rate of change of nerve root displacement in the intervertebral foramen is smaller than that in the nerve root on the outside area (p <0.05). Extraforaminal ligaments can absorb part of the pulling load of the nerve root; the C5 nerve root has the largest load range. Conclusions Cervical extraforaminal ligaments can disperse the tension load on the nerve root and play a role in protecting the nerve root. The protective effect of the C5 nerve root was the strongest, and this may anatomically explain why the C5 nerve roots are less prone to simple avulsion.

Clinical Characteristics of Spinal Nerve Sheath Tumors: Analysis of 149 Cases

Neurosurgery ◽  
2005 ◽  
Vol 56 (3) ◽  
pp. 510-515 ◽  
Author(s):  
Takahiro Jinnai ◽  
Minoru Hoshimaru ◽  
Tsunemaro Koyama
Keyword(s):  
Nerve Root ◽  
Spinal Nerve ◽  
Nerve Sheath Tumor ◽  
Spinal Nerve Root ◽  
Intervertebral Foramen ◽  
Nerve Roots ◽  
Nerve Sheath Tumors ◽  
Nerve Sheath ◽  
Caudal Portion ◽  
Rostral Portion

Abstract OBJECTIVE: Spinal nerve sheath tumors arise from the spinal nerve root and grow along it. There are two sites at which the growth of a tumor is restricted: the dural aperture for the spinal nerve root and the intervertebral foramen. This article describes the growth pattern of a spinal nerve sheath tumor along the spinal nerve root at various spinal levels. METHODS: We retrospectively reviewed the records for 149 patients with spinal nerve sheath tumors who were treated between 1980 and 2001. Of these, 176 resected tumors were classified into five groups according to the relationship to the dura mater and/or the intervertebral foramen. RESULTS: Strictly intradural tumors compose 8% of nerve sheath tumors of the first two cervical nerve roots. The percentage of these tumors increased gradually from the high cervical region to the thoracolumbar region, where it was more than 80%. In contrast, the percentage of strictly extradural tumors gradually decreased from the rostral portion to the caudal portion. Similarly, a percentage of tumors extending outside the spinal canal decreased from the rostral portion to the caudal portion. These changes of the growth pattern may be explained by the anatomic features of the spinal nerve roots, which have a longer intradural component at the more caudal portion of the spinal axis. CONCLUSION: The anatomic relationship of a nerve sheath tumor with the dura mater and the intervertebral foramen varies depending on the level of the tumor. This knowledge may help us to create a strategy for total resection of a nerve sheath tumor.

Extradural Characteristics of the Origins of Lumbosacral Nerve Roots

2018 ◽  
Vol 80 (02) ◽  
pp. 109-115 ◽  
Author(s):  
Viktor Matejcik ◽  
Roman Kuruc ◽  
Ján Líška ◽  
Juraj Steno ◽  
Zora Haviarova
Keyword(s):  
Nerve Root ◽  
Spinal Nerve ◽  
Intervertebral Foramen ◽  
Nerve Roots ◽  
Lumbosacral Region ◽  
Dural Sac ◽  
Comprehensive Knowledge ◽  
Different Types ◽  
Herniated Disk ◽  
Sacral Hiatus

Background and Study Aims A great number of unsuccessful intervertebral herniated disk surgeries in the lumbosacral region have highlighted the importance of a comprehensive knowledge of the different types of nerve root anomalies. That knowledge gained by anatomical studies (and intraoperative findings) might contribute to better results. In our study we focused on intraspinal extradural lumbosacral nerve root anomalies and their possible role in radiculopathy. Material and Methods The study was performed on 43 cadavers within 24 hours after death (32 men and 11 women). Bodies were dissected in the prone position, and a laminectomy exposed the entire spinal canal for the bilateral examination of each spinal nerve root from its origin to its exit through the intervertebral foramen or sacral hiatus. Uncommon extradural features in the lumbosacral region were pursued and documented. The spinal dural sac was also opened, aimed at recognizing the normotyped, prefixed, or postfixed type of plexus. Results A total of 20.93% of anomalies of extradural lumbosacral nerve root origins were observed, with the normotyped plexus prevailing. We observed atypical spacing of exits of lumbosacral roots (four cases), two roots leaving one intervertebral foramen (one case), extradural anastomoses (two cases), and missing extradural nerve root courses (two cases). The results were differentiated according to the normotyped, prefixed, or postfixed plexus type. Conclusion Results of similar studies dealing with anomalies of lumbosacral nerve roots were aimed at improving the results of herniated disk surgeries because ∼ 10% of misdiagnoses are related to ignorance of anatomical variability. Our observations may help explain the differences between the clinical picture and generally accepted anatomical standards.

Lumbosacral intersegmental epispinal axons and ectopic ventral nerve rootlets

1987 ◽  
Vol 67 (2) ◽  
pp. 269-277 ◽  
Author(s):  
Wesley W. Parke ◽  
Ryo Watanabe
Keyword(s):  
Nerve Root ◽  
Sensory Nerve ◽  
Conus Medullaris ◽  
Spinal Nerve ◽  
Nerve Fibers ◽  
Ventral Horn ◽  
Spinal Nerve Roots ◽  
Nerve Roots ◽  
Content Type ◽  
Almost All

✓ An epispinal system of motor axons virtually covers the ventral and lateral funiculi of the human conus medullaris between the L-2 and S-2 levels. These nerve fibers apparently arise from motor cells of the ventral horn nuclei and join spinal nerve roots caudal to their level of origin. In all observed spinal cords, many of these axons converged at the cord surface and formed an irregular group of ectopic rootlets that could be visually traced to join conventional spinal nerve roots at one to several segments inferior to their original segmental level; occasional rootlets joined a dorsal nerve root. As almost all previous reports of nerve root interconnections involved only the dorsal roots and have been cited to explain a lack of an absolute segmental sensory nerve distribution, it is believed that these intersegmental motor fibers may similarly explain a more diffuse efferent distribution than has previously been suspected.

Anatomy of the L5 nerve root in the pelvis for safe sacral screw placement: a cadaveric study

2021 ◽  
pp. 1-6
Author(s):  
Shota Tamagawa ◽  
Takatoshi Okuda ◽  
Hidetoshi Nojiri ◽  
Tatsuya Sato ◽  
Rei Momomura ◽  
...  
Keyword(s):  
Nerve Root ◽  
Sagittal Plane ◽  
Pedicle Screws ◽  
Cadaveric Study ◽  
Nerve Roots ◽  
Nerve Root Injury ◽  
Inflection Points ◽  
Root Injury ◽  
The Right ◽  
Intervertebral Foramina

OBJECTIVE Previous reports have focused on the complications of L5 nerve root injury caused by anterolateral misplacement of the S1 pedicle screws. Anatomical knowledge of the L5 nerve root in the pelvis is essential for safe and effective placement of the sacral screw. This cadaveric study aimed to investigate the course of the L5 nerve root in the pelvis and to clarify a safe zone for inserting the sacral screw. METHODS Fifty-four L5 nerve roots located bilaterally in 27 formalin-fixed cadavers were studied. The ventral rami of the L5 nerve roots were dissected along their courses from the intervertebral foramina to the lesser pelvis. The running angles of the L5 nerve roots from the centerline were measured in the coronal plane. In addition, the distances from the ala of the sacrum to the L5 nerve roots were measured in the sagittal plane. RESULTS The authors found that the running angles of the L5 nerve roots changed at the most anterior surface of the ala of the sacrum. The angles of the bilateral L5 nerve roots from the right and left L5 intervertebral foramina to their inflection points were 13.77° ± 5.01° and 14.65° ± 4.71°, respectively. The angles of the bilateral L5 nerve roots from the right and left inflection points to the lesser pelvis were 19.66° ± 6.40° and 20.58° ± 5.78°, respectively. There were no significant differences between the angles measured in the right and left nerve roots. The majority of the L5 nerves coursed outward after changing their angles at the inflection point. The distances from the ala of the sacrum to the L5 nerve roots in the sagittal plane were less than 1 mm in all cases, which indicated that the L5 nerve roots were positioned close to the ala of the sacrum and had poor mobility. CONCLUSIONS All of the L5 nerve roots coursed outward after exiting the intervertebral foramina and never inward. To prevent iatrogenic L5 nerve root injury, surgeons should insert the S1 pedicle screw medially with an angle > 0° toward the inside of the S1 anterior foramina and the sacral alar screw laterally with an angle > 30°.

Prostaglandin E2 catabolism in the spinal nerve roots of the cat

1980 ◽  
Vol 58 (2) ◽  
pp. 227-229 ◽  
Author(s):  
I. Bishai ◽  
F. Coceani
Keyword(s):  
Spinal Cord ◽  
Nerve Root ◽  
Peripheral Nerves ◽  
Spinal Nerve ◽  
Spinal Nerve Roots ◽  
Chromatographic Mobility ◽  
Nerve Roots ◽  
Spinal Roots ◽  
Metabolic Degradation ◽  
Rate Limiting

Catabolism of prostaglandin (PG) E2 was studied in homogenates of spinal cord and spinal nerve roots of the cat. Spinal roots enzymatically converted PGE2 to a product (metabolite I) with the chromatographic mobility of 15-keto-PGE2. Little metabolic degradation occurred in the spinal cord; however, incubation of PGE2 with combined spinal cord and nerve root tissue yielded a second metabolite (metabolite II) in addition to metabolite I. Metabolite II was identified as 15-keto-13,14-dihydro-PGE2. These results prove that spinal nerve roots, unlike the spinal cord, contain 15-hydroxyprostaglandin dehydrogenase (15-PGDH) which is the major and rate-limiting enzyme in the inactivation of prostaglandins. The location and functional significance of 15-PGDH in peripheral nerves remain to be elucidated.

Biomechanics of the lumbar spinal nerve roots and the first sacral root within the intervertebral foramina

1989 ◽  
Vol 11 (3) ◽  
pp. 221-225 ◽  
Author(s):  
F. de Peretti ◽  
J. P. Micalef ◽  
A. Bourgeon ◽  
C. Argenson ◽  
P. Rabischong
Keyword(s):  
Spinal Nerve ◽  
Spinal Nerve Roots ◽  
Nerve Roots ◽  
Lumbar Spinal ◽  
Intervertebral Foramina

Meningeal-neural relations in the intervertebral foramen

1974 ◽  
Vol 40 (6) ◽  
pp. 756-763 ◽  
Author(s):  
Sydney Sunderland
Keyword(s):  
Vertebral Column ◽  
Transverse Process ◽  
Spinal Nerve ◽  
Intervertebral Foramen ◽  
Nerve Roots ◽  
Content Type ◽  
Spinal Nerves ◽  
Strong Attachment ◽  
Relationship Of ◽  
The Relationship

✓ The relationship of the meninges internally to the nerve roots, posterior root ganglion, and spinal nerve, and externally to the wall of the intervertebral foramen, has been investigated. The neural structures and their coverings are not attached to the foramen. Only the fourth, fifth, and sixth cervical spinal nerves have a strong attachment to the vertebral column, and this is to the gutter of the vertebral transverse process. The observations have relevance to any local lesion that may fix, deform, or otherwise affect the nerve and nerve roots to the point of interfering with their function. They may also be important to traction injuries of nerve roots.

Ex Vivo Assessment of an Ultrasound-Guided Injection Technique of the Lumbosacral Disc in the Horse

2019 ◽  
Vol 32 (05) ◽  
pp. 383-388
Author(s):  
Mickaël Robert ◽  
Hadrien Manet ◽  
Guillaume Manneveau ◽  
Olivier Geffroy
Keyword(s):  
Clinical Practice ◽  
Ultrasound Guidance ◽  
Ex Vivo ◽  
Spinal Nerve ◽  
Injection Technique ◽  
Main Difficulty ◽  
Intervertebral Foramen ◽  
Spinal Nerve Roots ◽  
Ultrasound Guided ◽  
Nerve Roots

Abstract Objectives The aim of this study was to describe an ultrasound-guided injection technique of the lumbosacral disc in horses through the cranial vertebral notch of the sacrum and to evaluate both accuracy and potential complications of the technique on equine cadavers. Materials and Methods Twenty-four injections of the lumbosacral area were performed on 12 equine cadavers shortly after euthanasia under ultrasound guidance with the horse in recumbency using two different dyes (one colour for each side). The lumbosacral area was dissected in each horse and the accuracy of the technique, as well as its potential complications, was evaluated detecting the dyes and the structures that have been coloured. Results The lumbosacral area was correctly reached in only 11/24 injections. However, this technique allowed a lumbosacral peridiscal injection in 7/12 horses. The main difficulty was reaching the ventral opening of the L6-S1 intervertebral foramen that is partially hidden by the iliac wing on ultrasound. Puncture of the vertebral canal has been observed in 11/24 cases. The L6 spinal nerve roots emerging through the intervertebral foramen could potentially be damaged when inserting the needle. Clinical Significance The described ultrasound-guided technique allows peridiscal injection in the lumbosacral space in less than 60% of cases with potential sciatic nerve damage. Further investigations are warranted before using this technique in clinical practice in horses suffering from lumbosacral lesions.

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