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°.

Guideline update for the performance of fusion procedures for degenerative disease of the lumbar spine. Part 15: Electrophysiological monitoring and lumbar fusion

2014 ◽  
Vol 21 (1) ◽  
pp. 102-105 ◽  
Author(s):  
Alok Sharan ◽  
Michael W. Groff ◽  
Andrew T. Dailey ◽  
Zoher Ghogawala ◽  
Daniel K. Resnick ◽  
...  
Keyword(s):  
Nerve Root ◽  
Lumbar Fusion ◽  
Pedicle Screws ◽  
Limited Evidence ◽  
Direct Stimulation ◽  
Nerve Roots ◽  
Fusion Surgery ◽  
Nerve Root Injury ◽  
Root Injury ◽  
Stimulation Of

Intraoperative monitoring (IOM) is commonly used during lumbar fusion surgery for the prevention of nerve root injury. Justification for its use stems from the belief that IOM can prevent nerve root injury during the placement of pedicle screws. A thorough literature review was conducted to determine if the use of IOM could prevent nerve root injury during the placement of instrumentation in lumbar or lumbosacral fusion. There is no evidence to date that IOM can prevent injury to the nerve roots. There is limited evidence that a threshold below 5 mA from direct stimulation of the screw can indicate a medial pedicle breach by the screw. Unfortunately, once a nerve root injury has taken place, changing the direction of the screw does not alter the outcome. The recommendations formulated in the original guideline effort are neither supported nor refuted with the evidence obtained with the current studies.

scholarly journals A novel anatomo-physiologic high-grade spondylolisthesis model to evaluate L5 nerve stretch injury after spondylolisthesis reduction

2021 ◽  
Author(s):  
Basem Ishak ◽  
Clifford A. Pierre ◽  
Darius Ansari ◽  
Stefan Lachkar ◽  
Alexander von Glinski ◽  
...  
Keyword(s):  
Nerve Root ◽  
Nerve Palsy ◽  
Mechanical Strain ◽  
Pedicle Screws ◽  
High Grade ◽  
Nerve Roots ◽  
Nerve Root Injury ◽  
Root Injury ◽  
Fresh Frozen ◽  
Measurable Change

AbstractL5 nerve palsy is a well-known complication following reduction of high-grade spondylolisthesis. While several mechanisms for its occurrence have been proposed, the hypothesis of L5 nerve root strain or displacement secondary to mechanical reduction remains poorly studied. The aim of this cadaveric study is to determine changes in morphologic parameters of the L5 nerve root during simulated intraoperative reduction of high-grade spondylolisthesis. A standard posterior approach to the lumbosacral junction was performed in eight fresh-frozen cadavers with lumbosacral or lumbopelvic screw fixation. Wide decompressions of the spinal canal and L5 nerve roots with complete facetectomies were accomplished with full exposure of the L5 nerve roots. A 100% translational slip was provoked by release of the iliolumbar ligaments and cutting the disc with the attached anterior longitudinal ligament. To evaluate the path of the L5 nerves during reduction maneuvers, metal bars were inserted bilaterally at the inferomedial aspects of the L5 pedicle at a distance of 10 mm from the midpoint of the L5 pedicle screws. There was no measurable change in length of the L5 nerve roots after 50% and 100% reduction of spondylolisthesis. Mechanical strain or displacement during reduction is an unlikely cause of L5 nerve root injury. Further anatomical or physiological studies are necessary to explore alternative mechanisms of L5 nerve palsy in the setting of high-grade spondylolisthesis correction, and surgeons should favor extensive surgical decompression of the L5 nerve roots when feasible.

scholarly journals Accidental Strangulation with Cervical Nerve Root Injury Caused by the Entrapment of Clothing in a Soybean Milling Machine

2019 ◽  
Vol 2019 ◽  
pp. 1-3
Author(s):  
Kazuhiko Omori ◽  
Ikuto Takeuchi ◽  
Youichi Yanagawa
Keyword(s):  
Nerve Root ◽  
Electrical Machine ◽  
Milling Machine ◽  
Cervical Nerve Root ◽  
Cervical Nerve ◽  
Pattern Of Injury ◽  
Nerve Root Injury ◽  
Root Injury ◽  
Creatine Phosphokinase Level ◽  
The Right

The clothing of a forty-five-year-old man became entrapped by the mixing rotator while he was operating a soybean milling machine. His clothing was wound around the rotator, and tightened around his neck and chest, causing strangulation and a loss of consciousness. He was rescued by his coworkers and transported to our hospital by helicopter. Upon arrival, he regained consciousness. A physiological examination revealed multiple petechiae on his face and strangulation marks with subcutaneous hemorrhage on his neck and upper trunk. In addition, he had motor weakness of the right upper extremity and bilateral paresthesia from C5 to Th1. All radiological studies were negative. He was admitted for observation. After the patient’s creatine phosphokinase level peaked and his focal neurological signs improved, he was discharged on foot on the 6th hospital day. Accidental ligature strangulation with cervical nerve root injury, in which an article of clothing is caught in an electrical machine and strangles the wearer, is very rare. This case is presented for its rarity and the unique pattern of injury.

Placement of thoracolumbar pedicle screws using three-dimensional image guidance: experience in a large patient cohort

2009 ◽  
Vol 10 (1) ◽  
pp. 33-39 ◽  
Author(s):  
Eric W. Nottmeier ◽  
Will Seemer ◽  
Phillip M. Young
Keyword(s):  
Revision Surgery ◽  
Nerve Root ◽  
Image Guidance ◽  
Three Dimensional ◽  
Pedicle Screws ◽  
Ct Scanning ◽  
3D Image ◽  
Nerve Root Injury ◽  
Large Patient ◽  
Root Injury

Object The goal of this study was to analyze the placement accuracy and complications of thoracolumbar pedicle screws (PSs) inserted using 3D image guidance in a large patient cohort. Methods The authors reviewed the charts of 220 consecutive patients undergoing posterior spinal fusion using 3D image guidance for instrumentation placement. A total of 1084 thoracolumbar PSs were placed using either the BrainLAB Vector Vision (BrainLAB, Inc.) or Medtronic StealthStation Treon (Medtronic, Inc.) image guidance systems. Postoperative CT scanning was performed in 184 patients, allowing for 951 screws to be graded by an independent radiologist for bone breach. All complications resulting from instrumentation placement were noted. Using the intraoperative planning function of the image-guided system, the largest diameter screw possible in each particular case was placed. The screw diameter of instrumentation placed into the L3–S1 levels was noted. Results No vascular or visceral complications occurred as a result of screw placement. Two nerve root injuries occurred in 1084 screws placed, resulting in a 0.2% per screw incidence and a 0.9% patient incidence of nerve root injury. Neither nerve root injury was associated with a motor deficit. The breach rate was 7.5%. Grade 1 and minor anterolateral “tip out” breaches accounted for 90% of the total breaches. Patients undergoing revision surgery accounted for 46% of the patients in this study. Accordingly, 154 screws placed through previous fusion mass could be evaluated using postoperative CT scanning. The breach rate in this specific cohort was 7.8%. A total of 765 PSs were placed into the L3–S1 levels in this study; 546 (71%) of these screws were ≥ 7.5 mm in diameter. No statistical difference in breach rate was noted in PSs placed through revision spinal levels versus nonrevision spinal levels (p = 0.499). Additionally, no increase in breach rate was noted with placement of 7.5-mm-diameter screws. Conclusions Three-dimensional image guidance is a useful adjunct to placement of spinal instrumentation. The complication rate in this study was low, and accurate placement of instrumentation was achieved despite the high percentage of revision surgery cases in our patient population. Additionally, because active fluoroscopy was not used for instrumentation placement, there was minimal to no radiation exposure to the surgeon or operating room staff.

Riluzole effects on behavioral sensitivity and the development of axonal damage and spinal modifications that occur after painful nerve root compression

2014 ◽  
Vol 20 (6) ◽  
pp. 751-762 ◽  
Author(s):  
Kristen J. Nicholson ◽  
Sijia Zhang ◽  
Taylor M. Gilliland ◽  
Beth A. Winkelstein
Keyword(s):  
Spinal Cord ◽  
Dorsal Horn ◽  
Nerve Root ◽  
Mechanical Allodynia ◽  
Thermal Hyperalgesia ◽  
Neuronal Firing ◽  
Nerve Roots ◽  
Nerve Root Injury ◽  
Root Injury ◽  
Behavioral Sensitivity

Object Cervical radiculopathy is often attributed to cervical nerve root injury, which induces extensive degeneration and reduced axonal flow in primary afferents. Riluzole inhibits neuro-excitotoxicity in animal models of neural injury. The authors undertook this study to evaluate the antinociceptive and neuroprotective properties of riluzole in a rat model of painful nerve root compression. Methods A single dose of riluzole (3 mg/kg) was administered intraperitoneally at Day 1 after a painful nerve root injury. Mechanical allodynia and thermal hyperalgesia were evaluated for 7 days after injury. At Day 7, the spinal cord at the C-7 level and the adjacent nerve roots were harvested from a subgroup of rats for immunohistochemical evaluation. Nerve roots were labeled for NF200, CGRP, and IB4 to assess the morphology of myelinated, peptidergic, and nonpeptidergic axons, respectively. Spinal cord sections were labeled for the neuropeptide CGRP and the glutamate transporter GLT-1 to evaluate their expression in the dorsal horn. In a separate group of rats, electrophysiological recordings were made in the dorsal horn. Evoked action potentials were identified by recording extracellular potentials while applying mechanical stimuli to the forepaw. Results Even though riluzole was administered after the onset of behavioral sensitivity at Day 1, its administration resulted in immediate resolution of mechanical allodynia and thermal hyperalgesia (p < 0.045), and these effects were maintained for the study duration. At Day 7, axons labeled for NF200, CGRP, and IB4 in the compressed roots of animals that received riluzole treatment exhibited fewer axonal swellings than those from untreated animals. Riluzole also mitigated changes in the spinal distribution of CGRP and GLT-1 expression that is induced by a painful root compression, returning the spinal expression of both to sham levels. Riluzole also reduced neuronal excitability in the dorsal horn that normally develops by Day 7. The frequency of neuronal firing significantly increased (p < 0.045) after painful root compression, but riluzole treatment maintained neuronal firing at sham levels. Conclusions These findings suggest that early administration of riluzole is sufficient to mitigate nerve root–mediated pain by preventing development of neuronal dysfunction in the nerve root and the spinal cord.

scholarly journals Nerve injury following ultrasound-guided nerve root block with 2% lidocaine for shoulder manipulation: a case report

2021 ◽  
Vol 49 (9) ◽  
pp. 030006052110477
Author(s):  
Soyoung Kwak ◽  
Min Cheol Chang
Keyword(s):  
Nerve Root ◽  
Rating Scale ◽  
Adhesive Capsulitis ◽  
Numeric Rating Scale ◽  
University Hospital ◽  
Nerve Root Block ◽  
Nerve Root Injury ◽  
Root Injury ◽  
Shoulder Abductor ◽  
The Right

Shoulder manipulation under ultrasound (US)-guided C5 and C6 nerve root block is effective for treating refractory adhesive capsulitis (AC). We herein report the development of cervical nerve root injury following manipulation under anesthesia (MUA) in a patient with AC. A 47-year-old woman underwent shoulder manipulation under US-guided C5 and C6 root block with 2% lidocaine for the management of AC-induced shoulder pain. For the procedure, 3 mL of 2% lidocaine (total of 6 mL) was injected around each C5 and C6 nerve root under US guidance. Seven days after the procedure, the patient visited a university hospital because of severe neuropathic pain (numeric rating scale score of 9) in the right anterior arm, lateral arm, and forearm areas. Sensory deficits in the corresponding C5 and C6 dermatomes and motor weakness of the right shoulder abductor, elbow flexor, and wrist extensor were observed. Electrophysiologic studies demonstrated C5 and C6 nerve root injury. The patient was diagnosed with right C5 and C6 nerve root injury following MUA, and lidocaine toxicity or ischemia was the suspected cause. Clinicians should be mindful of the possibility of this complication.

scholarly journals L5 nerve root injury caused by anterolateral malpositioning of loosened S1 pedicle screws: illustrative cases

2021 ◽  
Vol 1 (25) ◽  
Author(s):  
Shota Tamagawa ◽  
Takatoshi Okuda ◽  
Hidetoshi Nojiri ◽  
Rei Momomura ◽  
Muneaki Ishijima
Keyword(s):  
Conservative Treatment ◽  
Nerve Root ◽  
Pedicle Screws ◽  
Spinal Nerve ◽  
Leg Pain ◽  
Spinal Nerve Root ◽  
Nerve Root Injury ◽  
Initial Surgery ◽  
Root Injury ◽  
Correct Direction

BACKGROUND Although malpositioning of pedicle screws into the spinal canal and intervertebral foramen can cause spinal nerve root injuries, there are few reports of L5 nerve root injuries when S1 pedicle screws have been inserted anterolaterally. The authors report two cases of L5 nerve root injury caused by anterolateral malpositioning of loosened S1 pedicle screws. OBSERVATIONS In both patients, S1 pedicle screws were inserted toward the outside of the S1 anterior foramen, and the tip of the screws perforated the anterior sacral cortex. L5 nerve root impairment was not observed immediately after surgery. However, severe leg pain in the L5 area was observed after the S1 pedicle screws became loosened. In case 1, the symptoms could not be controlled with conservative treatment. Reoperation was performed 3 months after the initial surgery. In case 2, the symptoms gradually improved with conservative treatment because the area around the loosened S1 screw was surrounded by newly formed bone that stabilized the screws, as observed with computed tomography 1 year after surgery. LESSONS Surgeons should recognize that anterolateral malpositioning of S1 pedicle screws can cause L5 nerve root injury. The screws should be inserted in the correct direction without loosening.

PATHOANATOMIC BASIS FOR STRETCH-INDUCED LUMBAR NERVE ROOT INJURY WITH A REVIEW OF THE LITERATURE

Neurosurgery ◽  
2009 ◽  
Vol 65 (1) ◽  
pp. 161-168 ◽  
Author(s):  
Sameer A. Kitab ◽  
Vincent J. Miele ◽  
William F. Lavelle ◽  
Edward C. Benzel
Keyword(s):  
Spinal Deformity ◽  
Nerve Root ◽  
Nerve Roots ◽  
Nerve Root Injury ◽  
Functional Spinal Unit ◽  
Root Injury ◽  
Lumbar Nerve Root ◽  
The Face ◽  
Anterior Posterior

Abstract OBJECTIVE Persistent pain originating from a dysfunctional lumbar motion segment poses significant challenges in the clinical arena. Although the predominance of the existing spine literature has addressed nerve root compression as the principal cause of pain, it is equally likely that a stretch mechanism may be responsible for all or part of the pathology. METHODS The literature supporting the role of stretch damage as a primary cause of nerve root injury and pain was systematically reviewed. Pathoanatomic considerations between nerve roots and juxtaposed environment are described and correlated with the available literature. Potential anatomic relationships that may lead to stretch-induced injury are delineated. RESULTS A dynamic lumbar functional spinal unit that encloses a tethered nerve root can create significant stretch and/or compression. This phenomenon may be present in a variety of pathological conditions. These include anterior, posterior, and rotatory olisthesis as well as degenerative conditions such as the loss of disc interspace height and frank multisegment spinal deformity. Although numerous studies have demonstrated that stretch can result in nerve damage, the pathophysiology that may associate nerve stretch with chronic pain has yet to be determined. CONCLUSION The current literature concerning stretch-related injury to nerve roots is reviewed, and a conceptual framework for its diagnosis and treatment is proposed and graphically illustrated using cadaveric specimens. The dynamic biomechanical and functional interrelationships between neural structures and adjacent connective tissue elements are particularly important in the face of spinal deformity.

scholarly journals Utility of diffusion tensor imaging for guiding the treatment of lumbar disc herniation by percutaneous transforaminal endoscopic discectomy

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Jiaqi Li ◽  
Hao Cui ◽  
Zhipeng Liu ◽  
Yapeng Sun ◽  
Fei Zhang ◽  
...  
Keyword(s):  
Nerve Root ◽  
Diffusion Tensor ◽  
Lumbar Disc ◽  
Lateral Nerve ◽  
Nerve Roots ◽  
Nerve Root Injury ◽  
Post Surgery ◽  
Root Injury ◽  
Significant Difference ◽  
Endoscopic Discectomy

AbstractThe purpose of this study was to evaluate the utility of diffusion tensor imaging (DTI) for guiding the treatment of lumbar disc herniation (LDH) by percutaneous transforaminal endoscopic discectomy (PTED). We collected the clinical data of a total of 19 patients: 10 with unilateral S1 nerve root injury, 6 with unilateral L5 nerve root injury, and 3 with unilateral L5 and S1 nerve root injury. All patients underwent DTI before surgery, 3 days post-surgery, 30 days post-surgery, and 90 days post-surgery. The comparison of the fractional anisotropy (FA) values of compressed lateral nerve roots before surgery and 3, 30, and 90 days post-surgery demonstrated the recovery of nerve roots to be a dynamic process. A significant difference was found in the FA values between compressed lateral nerve roots preoperatively and normal lateral nerve roots before surgery, 3 days post-surgery and 30 days post-surgery (p < 0.05). There was no significant difference in FA values between compressed lateral nerve roots and normal ones 90 days post-surgery (p > 0.05). DTI can be used for the accurate diagnosis of LDH, as well as for postoperative evaluation and prognosis, and it is thus useful for the selection of surgical timing.

Rating Spinal Nerve Extremity Impairment Using the Sixth Edition

2009 ◽  
Vol 14 (4) ◽  
pp. 1-6
Author(s):  
Christopher R. Brigham
Keyword(s):  
Nerve Root ◽  
Spinal Nerve ◽  
Upper Extremities ◽  
Motor Deficits ◽  
Nerve Injuries ◽  
Sixth Edition ◽  
Federal Employee ◽  
Nerve Root Injury ◽  
Root Injury ◽  
Rating Process

Abstract The AMAGuides to the Evaluation of Permanent Impairment (AMA Guides), Sixth Edition, does not provide a separate mechanism for rating spinal nerve injuries as extremity impairment; radiculopathy was reflected in the spinal rating process in Chapter 17, The Spine and Pelvis. Certain jurisdictions, such as the Federal Employee Compensation Act (FECA), rate nerve root injury as impairment involving the extremities rather than as part of the spine. This article presents an approach to rate spinal nerve impairments consistent with the AMA Guides, Sixth Edition, methodology. This approach should be used only when a jurisdiction requires ratings for extremities and precludes rating for the spine. A table in this article compares sensory and motor deficits according to the AMA Guides, Sixth and Fifth Editions; evaluators should be aware of changes between editions in methodology used to assign the final impairment. The authors present two tables regarding spinal nerve impairment: one for the upper extremities and one for the lower extremities. Both tables were developed using the methodology defined in the sixth edition. Using these tables and the process defined in the AMA Guides, Sixth Edition, evaluators can rate spinal nerve impairments for jurisdictions that do not permit rating for the spine and require rating for radiculopathy as an extremity impairment.

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