Spinal Cord Nerve Roots Research Articles

Clinical diagnosis and surgical treatment of cervical spondylosis with distal upper extremity amyotrophy

Objective To summarize the clinical features of cervical spondylosis with distal upper extremity amyotrophy; and further analyze the clinical efficacy of cervical anterior decompression and fusion on cervical spondylosis with distal upper extremity amyotrophy. Methods Thirty cases of cervical spondylosis with distal upper extremity amyotrophy were analyzed retrospectively from June 2006 to June 2015. nineteen males and eleven females with an average age of 55.20±9.08 years (41 to 72 years) were included. The preoperative course was 1 to 108 months with a median of 6 months. The muscle extent of the affected group, the segmentation and location of spinal canal stenosis, and the results of neurophysiological examination were analyzed. The muscular strength recovery of atrophic muscles was evaluated by Manual Muscle Testing (MMT), and the clinical satisfaction was assessed at the last followed up. Results The muscles involved in patients of cervical spondylosis with distal upper extremity amyotrophy are mainly the thenar muscle (17 cases, 56.7%), interosseous muscle (15 cases, 50.0%), and shypothenar muscles (13 cases, 43.3%). Most cases of imaging findings showed multi-segmental degeneration, of which C5, 6 (24 cases, 80.0%), C6,7 (21 cases, 70.0%) segments were most common, and the types of anterior compression: 23 segments (33.5%) of the central type, 37 segments (54.4%) of the lateral-central type, and 8 segments (11.8%) of the foramen type. Neuroelectrophysiological examination showed that cervical spinal cord anterior horn cells or nerve root damage, the most commonly involved segments of C7, C8, T1(18 cases, 60.0%). The average follow-up time was 36.8 months. At the last follow-up, MMT assessment showed that thirteen patients (43.3%) in this group had muscle strength recovery for more than one grade at the last follow-up. The average clinical satisfaction was 73.4%. Conclusion The clinical diagnosis of cervical spondylosis with distal upper extremity amyotrophy requires a combination of clinical symptoms, imaging findings and neurophysiological examination results for comprehensive judgment. Cervical anterior decompression and fusion can effectively prevent the progression of cervical spondylosis in distal upper extremity amyotrophy patients, and some patients can get a good muscle recovery. Key words: Cervical vertebrae; Spinal cord compression; Muscular atrophy; Spinal fusion

Efficacy comparison between minimally invasive fixation and routine fixation of tracer in robot-assisted pedicle screw placement

Objective To investigate the clinical efficacy of modified tracer minimally invasive fixation in robot-assisted pedicle screw placement. Methods A prospective randomized controlled study was conducted to analyze the clinical data of 41 patients with thoracolumbar fresh fracture at the orthopaedics department of Karamay Central Hospital from July 2017 to December 2017. There were 20 males and 21 females, aged 25-55 years, with an average of 40.6 years. According to AO fracture typing, there were 28 patients with type A and 13 patients with type B. The patients underwent robot-assisted pedicle screw placement. Random number table method was used to divide the patients into the conventional group (20 patients) and modified group (21 patients). The conventional group was treated with conventional tracer fixation, and the modified group modified tracer minimally invasive fixation. A total of 92 pedicle screws were implanted in the conventional group and 96 pedicle screws were implanted in the modified group. The size of wound, wound bleeding, time of fixing the tracer, complications (spinal cord injury and nerve root injury when fixing the tracer), development of the tracer fixator and artifacts were recorded. The accuracy of nail placement was evaluated by 320-slice CT scan and Gertzbein-Robbins criteria. Results There was no significant difference in age, sex, diagnosis, transverse diameter of pedicle and e angle between the two groups (P>0.05). The wound size, wound bleeding, and time of fixing the tracer in the modified group were (6.00±1.26)mm, (1.38±0.22)ml and (1.42±0.17)minutes, respectively, while those of the conventional group were (40.16±5.71)mm, (11.61±1.15)ml, and (5.12±0.64)minutes respectively (P 0.05). Conclusion In the robot-assisted pedicle screw placement, the modified tracer minimally invasive fixation method is safe and less traumatic, with no side effect on the accuracy of pedicle screw placement. Key words: Robotics; Spinal fractures; Surgical procedures, minimally invasive; Tracer fixation

Biomechanical investigation of post-operative C5 palsy due to ossification of the posterior longitudinal ligament in different types of cervical spinal alignment

Post-operative C5palsies are among the most common complications seen after cervical surgery for ossification of the posterior longitudinal ligament (OPLL). Although C5 palsy is a well-known complication of cervical spine surgery, its pathogenesis is poorly understood and depends on many other factors. In this study, a finite element model of the cervical spine and spinal cord-nerve roots complex structures was developed. The changes in stress in the cord and nerve roots, posterior shift of the spinal cord, and displacement and elongation of the nerve roots after laminectomy for cervical OPLL were analyzed for three different cervical sagittal alignments (lordosis, straight, and kyphosis). The results suggest that high stress concentrated on the nerve roots after laminectomy could be the main cause of C5 palsy because ossification of ligaments increases spinal cord shifting and root displacement. The type of sagittal alignment had no influence on changes in cord stress after laminectomy, although cases of kyphosis with a high degree of occupying ratio resulted in greater increases in nerve root stress after laminectomy. Therefore, kyphosis with a high OPLL occupying ratio could be a risk factor for poor surgical outcomes or post-operative complications and should be carefully considered for surgical treatment.

A numerical investigation of intrathecal isobaric drug dispersion within the cervical subarachnoid space.

Intrathecal drug and gene vector delivery is a procedure to release a solute within the cerebrospinal fluid. This procedure is currently used in clinical practice and shows promise for treatment of several central nervous system pathologies. However, intrathecal delivery protocols and systems are not yet optimized. The aim of this study was to investigate the effects of injection parameters on solute distribution within the cervical subarachnoid space using a numerical platform. We developed a numerical model based on a patient-specific three dimensional geometry of the cervical subarachnoid space with idealized dorsal and ventral nerve roots and denticulate ligament anatomy. We considered the drug as massless particles within the flow field and with similar properties as the CSF, and we analyzed the effects of anatomy, catheter position, angle and injection flow rate on solute distribution within the cerebrospinal fluid by performing a series of numerical simulations. Results were compared quantitatively in terms of drug peak concentration, spread, accumulation rate and appearance instant over 15 seconds following the injection. Results indicated that solute distribution within the cervical spine was altered by all parameters investigated within the time range analyzed following the injection. The presence of spinal cord nerve roots and denticulate ligaments increased drug spread by 60% compared to simulations without these anatomical features. Catheter position and angle were both found to alter spread rate up to 86%, and catheter flow rate altered drug peak concentration up to 78%. The presented numerical platform fills a first gap towards the realization of a tool to parametrically assess and optimize intrathecal drug and gene vector delivery protocols and systems. Further investigation is needed to analyze drug spread over a longer clinically relevant time frame.

The Impact of Spinal Cord Nerve Roots and Denticulate Ligaments on Cerebrospinal Fluid Dynamics in the Cervical Spine

Cerebrospinal fluid (CSF) dynamics in the spinal subarachnoid space (SSS) have been thought to play an important pathophysiological role in syringomyelia, Chiari I malformation (CM), and a role in intrathecal drug delivery. Yet, the impact that fine anatomical structures, including nerve roots and denticulate ligaments (NRDL), have on SSS CSF dynamics is not clear. In the present study we assessed the impact of NRDL on CSF dynamics in the cervical SSS. The 3D geometry of the cervical SSS was reconstructed based on manual segmentation of MRI images of a healthy volunteer and a patient with CM. Idealized NRDL were designed and added to each of the geometries based on in vivo measurments in the literature and confirmation by a neuroanatomist. CFD simulations were performed for the healthy and patient case with and without NRDL included. Our results showed that the NRDL had an important impact on CSF dynamics in terms of velocity field and flow patterns. However, pressure distribution was not altered greatly although the NRDL cases required a larger pressure gradient to maintain the same flow. Also, the NRDL did not alter CSF dynamics to a great degree in the SSS from the foramen magnum to the C1 level for the healthy subject and CM patient with mild tonsillar herniation (∼6 mm). Overall, the NRDL increased fluid mixing phenomena and resulted in a more complex flow field. Comparison of the streamlines of CSF flow revealed that the presence of NRDL lead to the formation of vortical structures and remarkably increased the local mixing of the CSF throughout the SSS.

Analysis of neurological complications of spinal osteotomy for thoracolumbar and lumbar kyphosis in ankylosing spondylitis

Objective To analyze cause and preventative measures of neurological complications of spinal osteotomy for thoracolumbar and lumbar kyphosis in ankylosing spondylitis.Methods Data of 126 patients with kyphosis caused by ankylosing spondylitis,who had undergone spinal osteotomy in our hospital from January 2006 to January 2012,were retrospectively analyzed.Among them,18 patients developed neurological complications after spinal osteotomy,including 15 males and 3 females,aged from 25 to 56 years.The average preoperative Cobb angle of these patients was 76.3°.According to American Spinal Injury Association (ASIA) classification,all patients were rated as grade E.Results All 18 patients were followed up for 6 to 49 months (average,35 months).The postoperative Cobb angle ranged from 19° to 38° (average,27°).The average Cobb angle was corrected 49.3°.Neurological complications included spinal cord injury (3 cases) and nerve root injury (15 cases).The reasons of spinal cord injury consisted of sagittal migration of vertebra,spinal stenosis due to operation and iatrogenic cervical spine fracture and dislocation.The reasons of nerve root injury included compression injury (2 cases),malposition of screw (1 case) and excessive drag of nerve root during osteotomy (12 cases).Conclusion Nerve injury is one of the most serious complications of spinal osteotomy in the treatment of kyphosis in ankylosing spondylitis.The incidence of the neurological complications could be obviously reduced by fully decompressing,making patients in a proper surgical position,recognizing the pathological nature of ankylosing spondylitis and avoiding sagittal migration of osteotomy part. Key words: Spondylitis, ankylosing; Kyphosis; Osteotomy; Postoperative complications

9H-11 神経根の衝撃強度に及ぼす負荷方向の影響(OS-13(4) 組織特性の診療デバイスと臨床応用)

9H-11 神経根の衝撃強度に及ぼす負荷方向の影響(OS-13(4) 組織特性の診療デバイスと臨床応用)

Experimental bypass surgery between the spinal cord and caudal nerve roots for spinal cord injuries

Spinal cord injuries often cause permanent neurological deficits and are still considered as inaccessible to efficient therapy. Injured spinal cord axons are unable to spontaneously regenerate in adult mammalians. Re-establishing functional activity especially in the lower limbs by reinnervating the caudal infra-lesional territories could represent an attractive therapeutic strategy. For several years, we have studied and developed surgical bypasses using peripheral nerve grafts bridging the supra-lesional rostral spinal cord to the caudal infra-lesional lumbar roots. Main objectives were: 1- to overcome the spinal cord lesion and the consecutive glial barrier blocking the axonal regeneration; 2- to find and bring an alternative source of regenerating axons; 3- to guide those axons toward precisely definite targets (for example, lower limb muscles). We report here the results of our experimental research, which led us from animal experimental models (rodents, primates) to the first human experimentation. Limitations of the method (especially technical pitfalls) are numerous. However, we have obtained encouraging results in our attempts to "repair" the motor pathway. Functional recovery with strong evidence of centrifugal axonal regeneration from the spinal cord to the periphery has been observed. Regarding the sensory pathway, we have found evidence of centripetal axonal regeneration from the periphery toward the spinal cord. Further studies are obviously advocated, but our experimental model of spinal cord - nerve roots bypasses may be integrated in future "repair" strategies of both motor and sensory pathways following spinal cord injury.

Schwann cell myelination of the myelin deficient rat spinal cord following X-irradiation.

The myelin-deficient (md) rat is an X-linked myelin mutant that has an abnormality of oligodendrocytes and a severe paucity of myelin throughout the CNS. This lack of myelin makes it an ideal model in which to study the cellular interactions that occur when "foreign" myelinating cells are induced in the milieu of this nonmyelinated CNS. In this study, Schwann cells were induced in the lumbosacral spinal cord by exposing it to radiation, a technique demonstrated repeatedly in other nonmutant strains of rats. Md rats and their age-matched littermates were irradiated (3,000 to 4,000 R) at 3 days of age and perfused 16-22 days later after pulse labeling with tritiated thymidine. In the md rat, Schwann cell invasion progressed from the area of the spinal cord-nerve root junction and extended into the dorsal columns and adjacent gray matter. Autoradiographic evidence revealed that many of these cells incorporated 3H-thymidine, indicating that they were undergoing proliferation. Ultrastructural observations showed that there was an integration of these intraspinal Schwann cells with the cells normally occurring in this environment, i.e., oligodendrocytes and astrocytes. The extent of migration and division of Schwann cells, as well as their interactions with glial cells, were similar to those seen in the nonmutant irradiated littermates. These studies provide conclusive evidence that md rat axons are normal with respect to their ability to provide trophic and mitogenic signals to myelinating cells.

Idiopathic scoliosis from the point of view of the neuroradiologist.

There is a simple morphological interrelation between the growing spinal cord-nerve root complex and the vertebral column, not unlike that between the growing brain and skull. The shape of the enveloping vertebral skeleton mirrors the anatomical features of the enclosed neural contents. During the cranio-caudally directed growth, spurts of elongation of the vertebral column may be too rapid for the slower growth rate of the spinal cord and nerve roots. The resulting disproportion of growth between spine and nervous system is compensated for by adaptive scoliotic curvature of the otherwise normally growing spine. The proposed pathogenetic concept readily explains the main clinical features of the deformity and is supported by a spring model experiment.