Cervical Lamina Research Articles

Feasibility of Using Intraoperative Neurophysiological Monitoring for Detecting Bone Layer of Cervical Spine Surgery.

Intraoperative neurophysiological monitoring (IONM) as a guide to bone layer estimation was examined during posterior cervical spine lamina grinding. To explore the feasibility of IONM to estimate bone layer thickness. Cervical laminoplasty is a classic operation for cervical spondylosis. To increase safety and accuracy, surgery-assistant robots are currently being studied. It combines the advantages of various program awareness methods to form a feasible security strategy. In the field of spinal surgery, robots have been successfully used to help place pedicle screws. IONM is used to monitor intraoperative nerve conditions in spinal surgery. This study was designed to explore the feasibility of adding IONM to robot safety strategies. Chinese miniature pig model was used. Electrodes were placed on the lamina, and the minimum stimulation threshold of DNEP for each lamina was measured (Intact lamina, IL). The laminae were ground to measure the DNEP threshold after incomplete grinding (Inner cortical bone preserved, ICP) and complete grinding (Inner cortical bone grinded, ICG). Subsequently, the lateral cervical mass screw canal drilling was performed, and the t-EMG threshold of the intact and perforated screw canals was measured and compared. The threshold was significantly lower than that of the recommended threshold of DENP via percutaneous cervical laminae measurement. The DNEP threshold decreases with the process of laminae grinding. The DNEP threshold of the IL group was significantly higher than ICP and ICG group, while there was no significant difference between the ICP group and the ICG group. There was no significant relationship between the integrity of the cervical spine lateral mass screw path and t-EMG threshold. It is feasible to use DENP threshold to estimate lamina thickness. Cervical lateral mass screw canals by t-EMG showed no help to evaluate the integrity.

Surgical Treatment for Cervical Lamina Metastasis from Parathyroid Carcinoma: A Case Report.

Surgical Treatment for Cervical Lamina Metastasis from Parathyroid Carcinoma: A Case Report.

Freehand Regional Techniques for Subaxial Cervical Pedicle Screw Placement.

Although various subaxial cervical pedicle screw implantation techniques have been proposed, clinical operators have been unable to exactly determine the entry points and trajectory . The objective of this article is to propose freehand regional techniques (FRT) for subaxial cervical pedicle screw placements and to investigate the clinical effectiveness of FRT. A total of 80 consecutive patients who underwent open subaxial cervical pedicle screw fixation using FRT from January 2015 to December 2020 were retrospectively reviewed, and preoperative cervical computed tomography (CT) images were used to observe the entry point and screw trajectory. The horizontal and vertical lines at the center of the cervical lateral mass was marked, and the entry point was chosen at the outer upper quadrant of the lateral mass. Both sagittal and axial trajectories were determined by CT images, generally perpendicular to the cervical laminae. Screw implantation accuracy was assessed using postoperative CT. After virtually inserting pedicle screws by FRT on preoperative cervical CT images, all of the entry points were located in the outer upper quadrant of the lateral mass and the trajectory perpendicular to the cervical laminae was just parallel to the pedicle's axis. A total of 694 pedicle screws were placed by FRT clinically, with a 96% accuracy rate. Pedicle screw implantation by FRT for subaxial cervical spine can be performed with acceptable safety and accuracy.

SCANNING ELECTRON MICROSCOPIC (SEM) STUDY OF NEMATODE PARASITES OF GOAT IN LUCKNOW DISTRICT UTTAR PRADESH

The goat is a vital milk and meat production source in India and contributes to the national and international economy. Goat production faces multiple challenges; one major problem is parasites leading to high mortality and economic losses. Nematode parasites are major problems to livestock globally, characterized clinically by enteritis, anaemia, emaciation, dehydration, and death. This study revealed the morphological identification of nematode parasites (Haemonchus sp., Oesophagostomum sp., and Trichuris sp.) in goats in the Lucknow region (India). Morphological identification was done by SEM (Scanning Electron Microscope) with the help of Souls in 1982. Scanning electron microscope exposed some species-specific characters, total body length of parasites, posterior region of Haemonchus having well-developed Copulatory Bursa (CB), spicules, Dorsal ray (DR) Anterior region of Haemonchus having cervical papillae (CP), vulval flap, knob, and cervical lamina. Oesophagostomum showed that the collar region on the mouth part and Buccal Capsule (BC) is surrounded by External Corona Radiate (ECR) and Internal Corona Radiate (ICR). Trichuris sp. was showed the anterior end vulva region of the female, and the posterior end of the male was spirally coiled and spicular sheath covered with minute spines (S).

Presynaptic Interactions between Trigeminal and Cervical Nociceptive Afferents Supplying Upper Cervical Lamina I Neurons.

Cervical and trigeminal afferents innervate neighboring cranial territories, and their convergence on upper cervical dorsal horn neurons provides a potential substrate for pain referral in primary headache syndromes. Lamina I neurons are central to this mechanism, as they relay convergent nociceptive input to supraspinal pain centers. Unfortunately, little is known about the interactions between trigeminal and cervical afferents supplying Lamina I neurons. Here, we used rats of both sexes to show that cervical and trigeminal afferents interact via presynaptic inhibition, where monosynaptic inputs to Lamina I neurons undergo unidirectional as well as reciprocal presynaptic control. This means that afferent-driven presynaptic inhibition shapes the way trigeminal and cervical Aδ-fiber and C-fiber input reaches Lamina I projection neurons (PNs) and local-circuit neurons (LCNs). We propose that this inhibition provides a feedforward control of excitatory drive to Lamina I neurons that regulates their convergent and cervical-specific or trigeminal-specific processing modes. As a consequence, disruption of the trigeminal and cervical afferent-driven presynaptic inhibition may contribute to development of primary headache syndromes.SIGNIFICANCE STATEMENT Cervical and trigeminal afferents innervate neighboring cranial territories, and their convergence on upper cervical dorsal horn neurons provides a potential substrate for pain referral in primary headache syndromes. Lamina I neurons are central to this mechanism as they relay convergent nociceptive input to supraspinal pain centers. Here, we show that cervical and trigeminal afferents interact via presynaptic inhibition, where inputs to Lamina I neurons undergo unidirectional as well as reciprocal control. The afferent-driven presynaptic inhibition shapes the trigeminocervical Aδ-fiber and C-fiber input to Lamina I neurons. This inhibition provides control of excitatory drive to Lamina I neurons that regulates their convergent and cervical-specific or trigeminal-specific processing modes. Disruption of this control may contribute to development of primary headache syndromes.

Processing of trigeminocervical nociceptive afferent input by neuronal circuity in the upper cervical lamina I.

Afferents from the C2 spinal nerve (SN) and trigeminal nerve (TN) innervate neighboring cranial territories, and their convergence on the upper cervical dorsal horn neurons represents neural substrate of pain referral in primary headache disorders. Unfortunately, little is known about trigeminocervical input to the major spinal nociceptive projection area lamina I. Here, we used ex vivo brainstem-cervical cord preparation for the visually guided whole-cell recording from the upper cervical lamina I neurons. We show that 50% of them receive convergent monosynaptic input from both nerves, whereas 35% and 11% of neurons receive specific supply from the C2 SN and TN, respectively. Altogether, 10 distinct patterns of synaptic input from the C2 SN and TN to lamina I neurons could be identified. Although stimulation of both nerves evoked excitatory/inhibitory responses, more numerous pure inhibitory inputs arose from the TN. We show that cervical and trigeminal nociceptors converge on to lamina I projection and inhibitory neurons. Thus, trigeminocervical input in lamina I is processed in both nerve-specific and convergent circuitries. Afferent convergence on to inhibitory interneurons serves as a feedforward mechanism balancing excitatory drive to projection neurons. Disruption of this balance may cause pain in primary headache syndromes.

The feasibility of digital guidance drill template assisted expansive open-door laminoplasty

Objective: To explore The feasibility of digital guidance drill templates assisted expansive open-door laminoplasty. Methods: Ten specimens of normal adult cervical spine (C3-7) were selected, including six males and four females. The specimens aged 42-67 years, with an average age of (43.6±4.2) years. After CT scanning, the date was imported into Mimics software in DICOM format. 3D models were reconstructed and the position and depth of troughs on the open side and hinge side were selected for expansive open-door laminoplasty. Drill templates were designed and exported in STL, manufactured by 3D printing finally. Then drill templates were attached to the posterior part of cervical lamina and spinous process. Under guidance of templates, troughs of both sides were conducted by using a high-speed drill. Then the lamina is elevated and instrumentations were implanted. Postoperative CT scanning was conducted to record the fracture of trough on the hinge side. 3D reconstruction was performed again to compare the position and depth between theory and actual trough on both sides by paired t test. Results: A total of 50 drill templates were designed and manufactured. There was no occurrence of hinge fracture after operation. In C3-7, the distance range between the theory position of troughs on the open side and the midline was 11.8-14.4 mm, while in actual it was 11.4-14.0 mm. The distance range between the theory position of troughs on the hinge side and the midline was 11.6-14.3 mm; in actual, it was 10.9-14.0 mm. The theory depth range of trough on the hinge side was 3.0-3.8 mm, while the actual depth was 3.1-3.8 mm. According to the statistical analysis, the difference in the position of trough on the open side, the position of trough on the hinge side and the depth of trough on the hinge side between theory and actual were not statistically significant (all P>0.05). Conclusion: Digital guided template assisted open-door laminoplasty is a feasible technique, which can improve the accuracy and safety of the position and depth of the trough, and has clinical application value.

A New Solution to an Old Problem: Ultrasound-guided Cervical Retrolaminar Injection for Acute Cervical Radicular Pain: Prospective Clinical Pilot Study and Cadaveric Study.

Prospective clinical pilot study and cadaveric study. The aim of this study was to evaluate the spread of an ultrasound-guided interfascial plane blocks (UGIPBs) and its potential efficacy for cervical radiculopathy. Cervical radiculopathy is a common disorder, potentially leading to severe pain and disability. Conservative treatment with cervical epidural steroid injections (ESI) is limited by concerns regarding their safety. UGIPBs are used in cervical surgical procedures as part of the multimodal postoperative analgesia regimen however, were not described for cervical radiculopathy. Twelve patients with acute cervical radicular pain who failed conservative treatment and were candidates for surgery were offered a cervical retrolaminar injection. A solution of 4 mL lidocaine 0.5% and 10 mg dexamethasone was injected, assisted by ultrasound guidance, at the posterior aspect of the cervical lamina corresponding to the compressed nerve root level. Additionally, a cadaver study was carried to evaluate the contrast spread and infiltration into near structures, both anatomically and radiographically. Twelve patients underwent the procedure, with a mean follow-up time of 14.5 weeks. Average numerical rating scale improved from 7.25 at baseline to 2.83 following the injection (P < 0.001). Three patients received 2 to 3 injections without significant improvement and were eventually operated. No adverse events were reported.In the cadaver study, fluoroscopy demonstrated contrast spread between T1 and T3 caudally, C2 to C5 cranially and facet joints laterally. Anatomically, the dye spread was demonstrated up to C2 cranially, T1 caudally, the articular pillars of C4 to C7, and the neural foramen of C6 laterally. A solution injected into the cervical retrolaminar plane can diffuse in the cranial-caudal axis to C2-T3 and laterally to the facet joints and the cervical neural foramen. Our pilot study confirmed the feasibility of our study protocol. Future studies are needed to support our early results.Level of Evidence: 4.

Suitability of the Subaxial Cervical Laminae for Laminar Screws in the Pediatric Population: A Radiologic Anatomical Study

Introduction: The laminar screw method was popularized during recent years. Since no data exist in the literature on its suitability for subaxial levels in the pediatric population, a radiologic anatomical study was planned to evaluate the suitability of the laminae for laminar screws in children. Methods: The laminar thicknesses from C3 to C7 were measured in axial sections in 120 pediatric patients using computed tomography. The patients were divided into 3 age-groups: ages 4–6, 7–9, and 10–12. Each age-group consisted of 20 boys and 20 girls. The suitability of the laminae was evaluated for 3.5-mm-thick commercially available screws and also for the 3-mm screws that could be produced in the future. If the height of the base of the spinous process is ≥ 9 mm, the segment was accepted as suitable for the bilateral screw, and ≥5 mm is for the unilateral screw. Additionally, laminar thickness and length were measured for possible short screws longer than 15 mm in the laminae that were distally thin but proximally thick. Results: The C4 and C5 levels had the thinnest (2.77 ± 0.6 mm and 2.81 ± 0.6 mm, respectively) and C7 had the thickest laminae (4.66 ± 0.6 mm) in all age-groups. No significant differences were found between boys and girls and right and left laminae. According to the age-groups, an increase in laminar thickness was possible by growing, but only C7 laminae thickness was statistically different between 10–12 and 4–6 age-groups (p < 0.001). The last rate of the suitability was 9.1% for the 3.5-mm-thick screws and 13.75% for the 3-mm-thick screws after deletion of the bilateral insertion due to the short base of the spinous process and adding the possible short screws in the distally thin but proximally thick laminae. The rates increased with age, but the only statistically significant difference was found between 4–6- and 10–12-year-old age-groups (p < 0.001). Conclusions: Laminar screws may be suitable for some levels of C7, C6, and C3 even in the young pediatric population. The use of thinner screws (3 mm) may increase the suitability rate. Therefore, laminar screw choice may be considered as a salvage method in pediatric patients, and all laminae may be evaluated individually for suitability. This study did not evaluate the safety and efficacy of the method in children, and these issues must be studied further.

Sprengel Deformity with Omovertebral Bone Encroaching the Spinal Canal Causing Progressive Cervical Myelopathy: A Technical Case Report

An adult with Sprengel deformity and Klippel-Feil syndrome associated with an omovertebral bone has rarely been reported in literature. The omovertebral bone is an abnormal cartilaginous connection between the scapula and the cervical spine. Limited cases have previously been reported in the literature describing surgical intervention when neurologic deficits such as cervical myelopathy or radiculopathy are present. In the present case, an omovertebral bone extended into the cervical lamina resulting in cervical myeloradiculopathy requiring resection of the bony anomaly and cervicothoracic fusion. The omovertebral bone as an etiology for radiculopathy or myelopathy is rarely seen in an adult population, and surgical decompression and fusion should be considered with this constellation of anomalies.

A reproduceable in situ xenograft model of spinal glioma

BackgroundSpinal glioma is a nervous system tumor that tends to relapse and has no specific prognostic molecular biomarkers. Thus, a stable and reproduceable animal research model of spinal glioma is urgently needed. New methodWe established a new in situ tumor xenograft model of spinal glioma using nude mice. In this study, we implanted tumors into the cervical spinal cord of nude mice to mimic the pathological characteristics of the original tumors. ResultsThrough anatomical experiments, we found that the cervical lamina of mice was thinner, the intervertebral space was much wider, and the adhesion muscles were more easily separated. According to the examination of spinal cord sections, the best puncture point we identified was located 0.9 mm lateral to the posterior median line at the level of the line between the midpoints of the scapulae and at a depth of 0.9 mm. In the nude mouse xenograft experiment, the implanted tumor tissue retained the pathological characteristics of the original tumor. Comparison with existing method(s)This model used the cervical spinal cord as the puncture site and patient-derived primary tumor cells, which has never been performed before. Tumor cells could be injected directly without damaging the lamina. Thus, we could reduce the risk of man-made spinal cord injury and infection and avoid destroying the stability and integrity of the spine. ConclusionsThis study established a stable and reliable animal model of spinal glioma for further molecular research and targeted therapy development.

Dimensional Characterization of the Human Cervical Interlaminar Space as a Guide for Safe Application of Minimally Invasive Dilators.

The risk of interlaminar passage of a dilator into the cervical spinal canal in minimally invasive approaches is currently unknown. Among the various anthropometric data reported in the literature, there is no report of the interlaminar dimensions in the cervical spine. To report the cervical interlaminar dimensions in neutral, flexion, and extension. A total of 8 spines were sectioned into cervical (C2-T1) segments. Digitized coordinate data defining the locations and movements of chosen anatomic points on the laminar edges at a given spinal level were used to compute the dimensions during a static neutral posture, flexion, and extension positions to mimic the positions during surgery. Interlaminar dimensions were averaged and categorized for each vertebral level and spinal posture. Based on the reported measurements, the smallest diameter dilator in commonly used dilator sets has the potential to traverse the interlaminar space at all levels in flexion. In a neutral posture, the average interlaminar distance at C2-3, C6-7, and C7-T1 was still greater than 2.0 mm, the smallest diameter of the initial dilator. The largest interlaminar distance was at C6-7 in flexion (7.68±1.60 mm). Because dilators pass directly onto the cervical lamina without visualization of the midline structures, the interlaminar distances have increased relevance in the minimally invasive cervical approaches of foraminotomy and laminectomy. The data in this report demonstrate the theoretical risk of interlaminar passage with small diameter dilators in posterior minimally invasive approaches to the cervical spine.

Functional Pathway Between Cervical Spinal and Sympathetic Ganglia: A Neurochemical Foundation Between Neck Pain and Vertigo

Background: Cervical vertigo commonly concurs in patients with neck pain, but the concurrent mechanism of these 2 symptoms still remains unclear. We previously reported a bidirectional segmental nerve fiber connection between cervical spinal and sympathetic ganglia, which provided a hypothesis that this connection between the 2 ganglia may be the anatomic basis for the concurrence of neck pain and cervical vertigo. However, this concurrent mechanism needs biochemical and functional evidence. Objectives: This study aimed to investigate a possible noradrenergic pathway between cervical spinal and sympathetic ganglia. Study Design: We performed both clinical and laboratory research. Clinical observation was a prospective case–control study. Setting: Clinical study took place in our hospital; laboratory study was in an orthopedic laboratory. Methods: Cervical lamina block therapy used in patients with cervical vertigo was clinically evaluated; norepinephrine (NE) expressions in cervical sympathetic ganglia were analyzed using immunohistochemical staining after electrical stimulation to the cervical spinal ganglia; the influence of phentolamine local injection to the vertebrobasilar artery flow was experimentally measured. Results: Cervical lamina block therapy could significantly shorten the clinical hospital stays of patients with cervical vertigo (P = 0.000) and improve vertebral artery flow (P &lt; 0.05). NE expressions in superior cervical sympathetic ganglia (SCG) or inferior cervical sympathetic ganglia (ICG) increased significantly when ipsilateral C2 to C3 or C6 to C8 spinal ganglia were electrically stimulated, respectively. Adrenergic receptor block with phentolamine significantly inhibited the decrease of basilar artery (BA) flow induced by electrical stimulation of the cervical spinal ganglia. The change range of BA flow caused by stimulations of C2 to C3 and C6 to C8 spinal ganglia was more than that of C4 and C5. Limitations: The inpatients observed in this clinical study might be influenced by some factors including emotion, diet, sleep, and others. The limitations of the laboratory study included animal species and small sample size. Conclusions: Adrenergic system could play a part in cervical spinal ganglia altering the vertebrobasilar artery system. It could provide a neurochemical foundation between neck pain and vertigo, and that segmental functional connections exist between cervical spinal and sympathetic ganglia.

Trigeminal Aδ- and C-afferent supply of lamina I neurons in the trigeminocervical complex.

Nociceptive trigeminal afferents innervating craniofacial area, eg, facial skin and cranial meninges, project to a broad region in the medullary and upper cervical dorsal horn designated as the trigeminocervical complex. Lamina I neurons in the trigeminocervical complex integrate and relay peripheral inputs, thus playing a key role in both cranial nociception and primary headache syndromes. Because of the technically challenging nature of recording, the long-range trigeminal afferent inputs to the medullary and cervical lamina I neurons were not intensively studied so far. Therefore, we have developed an ex vivo brainstem-cervical cord preparation with attached trigeminal nerve for the visually guided whole-cell recordings from the medullary and cervical lamina I neurons. Two-thirds of recorded neurons generated intrinsic rhythmic discharges. The stimulation of the trigeminal nerve produced a complex effect; it interrupted the rhythmic discharge for hundreds of milliseconds but, if the neuron was silenced by a hyperpolarizing current injection, could elicit a discharge. The monosynaptic inputs from the trigeminal Aδ, high-threshold Aδ, low-threshold C, and C afferents were recorded in the medullary neurons, as well as in the cervical neurons located in the segments C1 to C2 and, to a lesser degree, in C3 to C4. This pattern of supply was consistent with our labelling experiments showing extensive cervical projections of trigeminal afferents. Excitatory inputs were mediated, although not exclusively, through AMPA/kainate and NMDA receptors, whereas inhibitory inputs through both GABA and glycine receptors. In conclusion, the trigeminocervical lamina I neurons receive a complex pattern of long-range monosynaptic and polysynaptic inputs from a variety of the trigeminal nociceptive afferents.

Feasibility of Sub-Axial Cervical Laminar Screws, Including C7, in the Indian Population: A Study on 50 Patients Using Computed Tomography-Based Morphometry Measurements.

Study DesignObservational study of computed tomography (CT) data.PurposeWe performed a CT-based radiographic analysis of sub-axial cervical lamina in the Indian population to assess the feasibility of laminar screws.Overview of LiteratureMorphometric studies have been performed for populations of various ethnic groups, but none exist for Indian populations.MethodsCervical spine CT scans of 50 adults with a minimum slice thickness of <2 mm (0.5–2 mm) were obtained from the database of a single center in northern India. Measurements (e.g., length, thickness, and height) were taken in millimeters along the axial, coronal, and sagittal planes. Three measurements were made to assess laminar anatomy, namely, the translaminar/screw length, laminar thickness, and sagittal laminar height.ResultsThe final sample comprised 500 laminae in 50 patients, resulting in 1,500 measurements. The mean translaminar lengths of the C3, C4, C5, C6, and C7 laminae were 19.48 mm, 19.60 mm, 19.61 mm, 20.49 mm, and 22.85 mm, respectively. The mean thick- , 19.60 , 19.60 mm, 19.61 mm, 20.49 mm, and 22.85 mm, respectively. The mean thick- mm, 19.61 mm, 20.49 mm, and 22.85 mm, respectively. The mean thick- , 19.61 , 19.61 mm, 20.49 mm, and 22.85 mm, respectively. The mean thick- mm, 20.49 mm, and 22.85 mm, respectively. The mean thick- , 20.49 , 20.49 mm, and 22.85 mm, respectively. The mean thick- mm, and 22.85 mm, respectively. The mean thick- , and 22.85 mm, respectively. The mean thick , and 22.85 mm, respectively. The mean thicknesses of these cervical laminae were 3.12 mm, 2.62 mm, 2.56 mm, 3.47 mm, and 5.20 mm, respectively. The mean sagittal heights of these laminae were 9.38 mm, 9.80 mm, 10.12 mm, 11.31 mm, and 13.84 mm, respectively. Except for the C7 vertebrae, all other levels had a success rate of <10% in the Indian population using the criteria of a laminar height of at least 9 mm and thickness of 4.5 mm. Limited success was achieved at the C5, C6, and C3 levels.ConclusionsTo the best of our knowledge, the present study is the only series on the feasibility of laminar screws in the sub-axial cervical spine in the Indian population. We found that Indian patients have smaller anatomical dimensions and thus, are not suitable for laminar screws in the sub-axial cervical spine, barring C7, which is contrary to findings for populations in western and south Asian countries.

Cervical lift-up laminoplasty with titanium basket plates after resection of intradural tumor.

Background:Performing cervical laminoplasty after wide laminectomy may be technically demanding. The unique technique of cervical lift-up laminoplasty using titanium basket plates was applied for the reconstruction of cervical laminae after wide laminectomy for the resection of intradural tumors.Materials and Methods:This technical study included 14 cases that could be followed periodically for at least 6 months after surgery. Participants were 8 male and 6 female, with a mean age of 41.6 years (range, 13–71 years). Tumors were intramedullary in 11 cases and extramedullary in 3 cases. After resection of intradural tumors, custom-designed titanium baskets were fitted to expand the spinal canal. Combining baskets of different sizes are also possible for each side at one level. A mixture of hydroxyapatite granules and collagen was packed into the basket. The reconstructed posterior laminae were secured using titanium mini plates. The fascia of the paravertebral muscles was sutured to the spino-ligamentous complex to further stabilize the posterior elements of the cervical spine.Results:No wounds or implant problems requiring revision surgery were recognized. Imaging analysis demonstrated no significant change in C2–C7 angle cervical range of motion between before and after surgery, suggesting sequential spinal stability at the base of the laminae.Conclusions:This technical note suggests that cervical lift-up laminoplasty with titanium basket plates appears practical and useful as a procedure to reconstruct cervical laminae after wide laminectomy.

Experimental rat model for cervical compressive myelopathy.

Previously, a rat model of chronic compressive myelopathy that uses a water-absorbing polymer inserted under a spinal lamina was reported. However, the best size and coefficient of expansion of the polymer sheet have not yet been established. The aim of the present study was to optimize these properties in an ideal rat model of cervical compressive myelopathy. Thirty rats were used in this study. A sheet of water-absorbing polymer was inserted under the cervical laminae. Rats were divided randomly into five experimental groups by the expansion rate (350 or 200%) and thickness (0.5 or 0.7 mm) and the control. After the surgery, the severity of paralysis was evaluated for 12 weeks. At 12 weeks after the surgery, cresyl violet staining was performed to assess the number of motor neurons in the anterior horn at the C4/C5 segment and Luxol Fast Blue staining was performed to assess demyelination in the corticospinal tract at the C7 segment. ‘Slow-progressive’ paralysis appeared at 4–8 weeks postoperatively in rat models using sheets with 200% expansion. By contrast, only temporary paralysis was observed in rat models using sheets with 350% expansion. A loss of motor neurons in the anterior horn was observed in all groups, except for the control. Demyelination in the corticospinal tract was observed in rat models using sheets with 200% expansion, but not rat models using sheets with 350% expansion. A polymer sheet that expands its volume by 200% is an ideal material for rat models of cervical compressive myelopathy.

Serotonergic mechanisms of trigeminal meningeal nociception: Implications for migraine pain

Serotonergic mechanisms play a central role in migraine pathology. However, the region-specific effects of serotonin (5-HT) mediated via multiple types of receptors in the nociceptive system are poorly understood. Using extracellular and patch-clamp recordings, we studied the action of 5-HT on the excitability of peripheral and central terminals of trigeminal afferents. 5-HT evoked long-lasting TTX-sensitive firing in the peripheral terminals of meningeal afferents, the origin site of migraine pain. Cluster analysis revealed that in majority of nociceptive fibers 5-HT induced either transient or persistent spiking activity with prevailing delta and theta rhythms. The 5-HT3-receptor antagonist MDL-72222 or 5-HT1B/D-receptor antagonist GR127935 largely reduced, but their combination completely prevented the excitatory pro-nociceptive action of 5-HT. The 5-HT3 agonist mCPBG activated spikes in MDL-72222-dependent manner but the 5HT-1 receptor agonist sumatriptan did not affect the nociceptive firing. 5-HT also triggered peripheral CGRP release in meninges, which was blocked by MDL-72222.5-HT evoked fast membrane currents and Ca2+ transients in a fraction of trigeminal neurons. Immunohistochemistry showed expression of 5-HT3A receptors in fibers innervating meninges. Endogenous release of 5-HT from degranulated mast cells increased nociceptive firing. Low pH but not histamine strongly activated firing. 5-HT reduced monosynaptic inputs from trigeminal Aδ- and C-afferents to the upper cervical lamina I neurons and this effect was blocked by MDL-72222. Consistent with central inhibitory effect, 5-HT reduced CGRP release in the brainstem slices. In conclusion, 5-HT evokes powerful pro-nociceptive peripheral and anti-nociceptive central effects in trigeminal system transmitting migraine pain.

Digital navigation enhances cervical pedicle screw placement accuracy and safety: study protocol of a randomized controlled trial

Background: A unified standard for cervical pedicle screw placement does not currently exist; therefore, it is difficult to quantitatively evaluate the clinical effects of the technique. Digital navigation can provide a reference for accurate and safe location, orientation, and placement of cervical pedicle screws. We hypothesized that compared with partial cervical lamina excision or the pipeline-dredge discharge method, digital navigation can greatly increase the accuracy and safety of cervical pedicle screw placement. Methods/Design: This was a prospective, single-center, randomized controlled, open-label trial. Seventy-six patients with cervical spine fracture scheduled to receive treatment in the Department of Orthopedics, Affiliated Hospital of Nantong University, China were randomly divided into three groups to undergo cervical pedicle screw internal fixation. Patients in the cervical lamina partial excision group ( n = 26, 160 screws) underwent partial cervical lamina excision and cervical pedicle screw internal fixation; those in the pipeline-dredge discharge group ( n = 27, 156 screws) underwent pipeline-dredge discharge and cervical pedicle screw internal fixation; and those in the digital navigation group ( n = 23, 162 screws) underwent digital navigation-assisted cervical pedicle placement. All patients were evaluated at 12 and 36 months. The primary outcome was the percentage of screws graded I when evaluating the penetration degree of the cervical pedicle screws, which evaluates the accuracy of screw placement, 12 months after internal fixation. Secondary outcomes included: (1) the percentage of screws graded I when evaluating the penetration degree of cervical pedicle screws 36 months after internal fixation; (2) bony fusion rate of the atlantoaxial joint, used to evaluate fracture healing, 12 and 36 months after internal fixation; (3) Visual Analogue Scale spine score, used to evaluate cervical neck pain, prior to and 12 and 36 months after internal fixation; (4) American Spinal Injury Association Classification, used to evaluate improvement in neurological function, prior to and 12 and 36 months after internal fixation; and (5) adverse events, used to evaluate the safety of each pedicle screw implantation method, 12 and 36 months after internal fixation. Discussion: This trial protocol compared the effects of three cervical pedicle screw internal fixation methods for the treatment of cervical spine fracture, and investigated and compared the accuracy and safety of digital navigation-assisted cervical pedicle screw placement with partial cervical lamina excision and pipeline-dredge discharge. We hoped to provide quantitative evidence for the clinical use of digital navigation in orthopedics, especially in cervical pedicle screw placement. Trial registration: ClinicalTrial.gov identifier: NCT02880839; registered on 19 August 2016. Ethics: This trial protocol has been approved by Medical Ethics Committee, Affiliated Hospital of Nantong University, China, and was performed in accordance with the guidelines of the Declaration of Helsinki , formulated by the World Medical Association. Informed consent: Signed informed consent regarding trial procedure and treatment was obtained from each patient.

A New Source of Structural Autograft for ACDF Surgery: Cervical Laminae

Background Autograft bone as a fusion substrate is still the gold standard in the procedure. However, few studies have reported that using autologous cervical laminae as the bone graft in ACDF during the combined posteroanterior cervical spine surgery. Objective This study aims to evaluate the feasibility of using autologous cervical laminae as the bone graft in ACDF and to describe the clinical and radiographic outcomes in patients undergoing combined posteroanterior cervical surgery using autologous laminae as bone graft in ACDF. Material and Methods Computed tomography (CT) scan of the cervical spine were performed in 50 adult cases. The heights of the laminae and the middle intervertebral space from C3 to C7 were measured on the CT planes. Then, 16 patients (nine males and seven females) with cervical spondylotic myelopathy underwent one-level combined posteroanterior procedure with anterior plate fixation from January 2010 to January 2013. Patients underwent combined posteroanterior surgery with laminectomy and ACDF. The structural laminae obtained from laminectomy were used as bone graft in ACDF. The clinical and radiographic outcomes of the patients were analyzed and the effectiveness and safety of the surgery was evaluated. Results The average height of the laminae and the middle intervertebral space from C3 to C7 were 11.18 ± 1.05 mm and the 5.75 ± 0.58 mm, respectively. Statistical significant difference was found between the heights of the laminae and the space ( p &lt; 0.001). All the patients were followed up and the average follow-up period was 25.5 ± 3.1 months. All patients had immediate postoperative resolution of symptoms and radiographic evidence of solid fusion 3 months later. Postoperatively, excellent results were reported in 62.5%, good results in 18.8%, and fair results in 18.8% of the patients according to Odom criteria. Visual analog scale score of the neck and extremities pain was significantly decreased after the surgery ( p = 0.014). The average preoperative and postoperative lordosis angles of the cervical spine were 24.42 ± 13.84 degrees and 32.91 ± 7.79 degrees, and the difference was significant ( p &lt; 0.01). Little loss of the angle was noted at final follow-up (32.91 ± 7.79 vs. 29.30 ± 7.88 degrees, p = 0.51). Anterior intervertebral space height was significantly increased ( p &lt; 0.001) after the surgery and a little declined at final follow-up ( p = 0.43). No intraoperative complication was noted in the patients and three patients got self-limiting dysphagia postoperatively, who recovered spontaneously. Conclusion The height of the cervical laminae is adequate for bone graft in ACDF. Structural autograft harvested from the laminae provides a viable alternative to AIC grafting.