Bony Spinal Canal Research Articles

Full-Endoscopic Posterior Lumbar Interbody Fusion: A Review and Technical Note

Remarkable innovations in spinal endoscopic surgery have broadened its applications over the past 20 years. Full-endoscopic fusions have been widely reported, and several full-endoscopic approaches for interbody fusion have been published. In general, full-endoscopic lumbar interbody fusion (LIF) is called Endo-LIF, and facet-preserving endo-LIF through the transforaminal route is called trans-Kambin’s triangle LIF, which has a relatively longer history than facet-sacrificing endo-LIF via the posterolateral route. Both approaches can reduce intraoperative and postoperative bleeding. However, there is a higher risk of subsidence and exit nerve root injury. There is no direct decompression in either of the interbody fusions, and additional decompression is required if there is severe lumbar bony canal stenosis. However, the posterior interlaminar approach, which is a well-known standard in full-endoscopic spine surgery, has rarely been applied in the field of endoscopic lumbar fusion surgery. Full-endoscopic posterior LIF (FE-PLIF) via an interlaminar approach can accomplish direct decompression of bony canal stenosis and safe interbody fusion. FE-PLIF via an interlaminar approach demonstrated a longer operation time, less blood loss, and shorter hospitalization duration than minimally invasive transforaminal LIF. FE-PLIF, which can accomplish direct decompression for bony spinal canal stenosis, is superior to other Endo-LIFs. However, FE-PLIF requires technical dexterity to improve efficiency and reduce technical complexity.

Establishment of the Lunar Phase Morphological Classification for Cervical Spinal Canal.

Retrospective clinical trial. To establish a morphological classification of the cervical spinal canal using its parameters. Cervical spine computed tomography (CT) data of 200 healthy volunteers in 2 years were analyzed. The morphology of the spinal cord was also analyzed. The median sagittal diameter and transverse diameter of the spinal canal from C2 to C7 were measured on CT images. The ratio of the median sagittal diameter to the transverse diameter was calculated. Accordingly, the spinal canal shape of each segment was classified into four, and the specific criteria of lunar phase classification were determined through linear discriminant analysis based on the ratio of the median sagittal diameter to the transverse diameter. The inter-rater reliability of the classification was explored using Kappa coefficients. Finally, the morphology of the different segments of the cervical spinal canal in healthy volunteers was revised and compared. According to the ratio of the median sagittal diameter and the transverse diameter of the cervical spinal canal, the lunar phase classification of the cervical bony spinal canal was determined as follows: full-moon >0.65, 0.55< convex-moon ≤0.65, 0.46≤ quarter-moon ≤0.55, and residual-moon <0.46. The Kappa values of C2-C7 were 0.851, 0.958, 0.823, 0.927, 0.793, and 0.946, and the Kappa value of all C2-C7 segments was 0.854 that mainly presented two forms of full-moon (76.5%) and convex-moon (23.0%). A quarter-moon spinal canal was mainly distributed in C3, C4, C5, and C6; a residual-moon spinal canal was mainly distributed in C4 and C5; and the morphological distribution of C4 and C5 were similar (p>0.05). The frequency of the spinal canal of the residual-moon type was the highest, and the full-moon (6.5%) and residual-moon (7.5%) types of C7 were rare. The morphological classification of the cervical spinal canal was established to present anatomical variations. The classification showed good inter-rater reliability.

Machine Learning Predicts Decompression Levels for Lumbar Spinal Stenosis Using Canal Radiomic Features from Computed Tomography Myelography.

The accurate preoperative identification of decompression levels is crucial for the success of surgery in patients with multi-level lumbar spinal stenosis (LSS). The objective of this study was to develop machine learning (ML) classifiers that can predict decompression levels using computed tomography myelography (CTM) data from LSS patients. A total of 1095 lumbar levels from 219 patients were included in this study. The bony spinal canal in CTM images was manually delineated, and radiomic features were extracted. The extracted data were randomly divided into training and testing datasets (8:2). Six feature selection methods combined with 12 ML algorithms were employed, resulting in a total of 72 ML classifiers. The main evaluation indicator for all classifiers was the area under the curve of the receiver operating characteristic (ROC-AUC), with the precision-recall AUC (PR-AUC) serving as the secondary indicator. The prediction outcome of ML classifiers was decompression level or not. The embedding linear support vector (embeddingLSVC) was the optimal feature selection method. The feature importance analysis revealed the top 5 important features of the 15 radiomic predictors, which included 2 texture features, 2 first-order intensity features, and 1 shape feature. Except for shape features, these features might be eye-discernible but hardly quantified. The top two ML classifiers were embeddingLSVC combined with support vector machine (EmbeddingLSVC_SVM) and embeddingLSVC combined with gradient boosting (EmbeddingLSVC_GradientBoost). These classifiers achieved ROC-AUCs over 0.90 and PR-AUCs over 0.80 in independent testing among the 72 classifiers. Further comparisons indicated that EmbeddingLSVC_SVM appeared to be the optimal classifier, demonstrating superior discrimination ability, slight advantages in the Brier scores on the calibration curve, and Net benefits on the Decision Curve Analysis. ML successfully extracted valuable and interpretable radiomic features from the spinal canal using CTM images, and accurately predicted decompression levels for LSS patients. The EmbeddingLSVC_SVM classifier has the potential to assist surgical decision making in clinical practice, as it showed high discrimination, advantageous calibration, and competitive utility in selecting decompression levels in LSS patients using canal radiomic features from CTM.

Lumbar spinal bony canal measurement in a Palestinian population using CT scan: a retrospective study

Purpose: Establishing the normal range of lumbar spinal canal in the Palestinian population helps provide a quantitative method for assessing spinal canal abnormalities in the lumbar region. Materials and Methods: The data was gathered from Governmental Hospital in Nablus from January to July 2018. It is a cross-sectional descriptive study among 400 patients (201 males, 199 females), ranging from 20 to 60 years. CT scan radiographs were used to measure the canal and the vertebral body diameters to obtain the canal body ratio. Results: The results represent the normal ratio of dimensions at each level of the bony lumbar spinal canal. The measurements presented are taken at the level of each lumbar vertebra starting from the 1st down to the fifth lumbar vertebra. It was found that the mean ratio of the spinal canal increases from L1 down to L5. Conclusion: After analyzing each lumbar level's results, the mean ratio of the spinal canal increases from L1 to L5. In addition, there were no significant differences between males and females regarding the measurement tool.

Complete removal of intraspinal extradural mass with unilateral biportal endoscopy.

Unilateral biportal endoscopic (UBE) technique can easily decompress the bony spinal canal and accommodate all open surgical instruments under endoscopic guidance. However, indications and reports of this technique have been limited to degenerative and infectious diseases. We used the UBE technique for the decompression and removal of extradural mass lesions in five patients. Under endoscopic guidance, a unilateral approach was used, and decompression and flavectomy were performed. After decompression, removal of the tumor was performed using various forceps. We evaluated the technical process of the procedure, the patient's pre- and postoperative symptoms, and operative radiology and pathologic results. Postoperative pain and disability improved clinically for all patients. Four patients were confirmed as having an epidural cyst and one patient was diagnosed with hemangioma. During follow-up, no recurrence was observed. We successfully removed five extradural mass lesions using a biportal endoscopic posterior approach without complications. The biportal endoscopic approach may have advantages, such as minimizing trauma to the normal structures, magnified endoscopic view, and early recovery after the surgery. Biportal endoscopy may be used as an alternative surgical treatment for symptomatic intraspinal extradural benign lesions.

Spinal Epidural Lipomatosis Causing Lumbar Canal Stenosis: A Pictorial Essay on Radiological Grading and the Role of Bariatric Surgery Versus Laminectomy

Spinal epidural lipomatosis (SEL) is a rare condition characterized by an excessive accumulation of adipose tissue in the spinal canal that can have a compressive effect on intraspinal neuroanatomical structures, leading to clinical symptoms. Several different conservative and surgical treatment strategies have been proposed but the treatment and outcomes remain controversial. There is a lack of severity-based evidence documenting the success of decompressive laminectomy in SEL and there are only anecdotal reports of clinico-radiological success with weight loss from bariatric surgery. This article demonstrates the resolution of SEL in two patients with bariatric surgery with the help of pre and postoperative MR imaging. The authors also highlight the classic “types” of spinal epidural lipomatosis with a surgically relevant grading system and elucidate the existence of concurrent extraspinal lipomatosis (i.e. mediastinal and intra-abdominal lipomatosis), drawing parallels with the natural history of SEL. The controversial question remains whether a symptomatic SEL patient needs a multilevel laminectomy for spinal decompression or bariatric surgery that can indirectly help the spinal condition. We propose that bariatric intervention could be better frontline management in patients with multifocal/multisystem lipomatosis (i.e., combined spinal and extraspinal) and spinal decompression would be ideal for those SEL patients with coexisting bony and/or ligamentous spinal canal or foraminal stenosis. This manuscript serves as a comprehensive and contemporary update on the radiological profile and two plausible treatment paths and will look toward further verification by a randomized clinical trial.

Abnormal spinal cord motion at the craniocervical junction in hypermobile Ehlers-Danlos patients.

The craniocervical junction (CCJ) is anatomically complex and comprises multiple joints that allow for wide head and neck movements. The thecal sac must adjust to such movements. Accordingly, the thecal sac is not rigidly attached to the bony spinal canal but instead tethered by fibrous suspension ligaments, including myodural bridges (MDBs). The authors hypothesized that pathological spinal cord motion is due to the laxity of such suspension bands in patients with connective tissue disorders, e.g., hypermobile Ehlers-Danlos syndrome (EDS). The ultrastructure of MDBs that were intraoperatively harvested from patients with Chiari malformation was investigated with transmission electron microscopy, and 8 patients with EDS were compared with 8 patients without EDS. MRI was used to exclude patients with EDS and craniocervical instability (CCI). Real-time ultrasound was used to compare the spinal cord at C1-2 of 20 patients with EDS with those of 18 healthy control participants. The ultrastructural damage of the collagen fibrils of the MDBs was distinct in patients with EDS, indicating a pathological mechanical laxity. In patients with EDS, ultrasound revealed increased cardiac pulsatory motion and irregular displacement of the spinal cord during head movements. Laxity of spinal cord suspension ligaments and the associated spinal cord motion disorder are possible pathogenic factors for chronic neck pain and headache in patients with EDS but without radiologically proven CCI.

Minimally Invasive Short-Segment Anteroposterior Surgery for Thoracolumbar Osteoporotic Fractures with Canal Compromise: A Prospective Study with a Minimum 2-Year Follow-up

Study DesignA prospective study with a minimum follow-up of 24 months.PurposeThis study aimed to evaluate the results of minimally invasive anteroposterior surgery for osteoporotic vertebral fractures (OVFs) associated with bony spinal canal compromise in elderly patients.Overview of LiteratureThere is a recent increase in the incidence of osteoporosis with OVFs, causing an increasing burden on medical systems.MethodsThe study included 47 patients, of whom 45 completed a minimum of 24-month follow-up. The inclusion criteria were OVF types 3 and 4 according to the osteoporotic fracture classification in patients aged ≥65 years with bony stenosis. The surgical management consisted of anterior corpectomy and decompression using a thoracoscopic or mini-laparotomy approach, together with posterior percutaneous cement-augmented short-segment fixation. Self-reported outcome measures included Visual Analog Scale (VAS) and Oswestry Disability Index (ODI) in the preoperative phase and regular follow-up at a minimum of 24 months. Radiological measures included segmental lordosis, dual-energy X-ray absorptiometry for osteoporosis assessment, and radiological fracture healing.ResultsThere were 33 patients with lumbar fracture and 12 patients with thoracic fracture. Thirteen patients had preoperative neurological deficits. The mean age was 77.4±8.3 years. The mean preoperative VAS score was 8.12±1.5, and the mean ODI score was 24.4±8.2. The mean preoperative sagittal Cobb angle was 6.3°±4.2° kyphosis. The mean operative time was 220.3±55.5 minutes, with a mean blood loss of 360.75±200.6 mL. After a mean follow-up of 32.6±6.4 months, the mean VAS significantly improved to 2.3, and the ODI to 12. Only three patients still had a partial neurological deficit. The mean final sagittal Cobb angle was significantly better, with 12.5°±4.3° of lordosis.ConclusionsShort-segment percutaneous fixation with cement augmentation combined with minimally invasive anterior decompression and corpectomy is a less invasive and safe approach in elderly patients with OVF and canal compromise.

Can a relatively large spinal cord for the dural sac influence severity of paralysis in elderly patients with cervical spinal cord injury caused by minor trauma?

Retrospective reviewThe degree of spinal cord compression and bony spinal canal stenosis are risk factors for the occurrence of spinal cord injury (SCI) without major fracture or dislocation, but they do not affect the severity of neurological symptoms. However, whether a relatively large spinal cord for the dural sac influences the severity of symptoms in SCI cases is unknown.The purpose of this study was to verify the influence of spinal cord size relative to dural sac on the severity of paralysis in elderly patients with cervical SCI caused by minor trauma.Subjects were 50 elderly patients with SCI caused by falls on flat ground. At 72 hours after injury, neurological assessment was performed using the Japanese Orthopaedic Association (JOA) scoring system. Bony canal anteroposterior diameters (APD) at mid C5 vertebral body were measured with computed tomography. We measured dural sac and spinal cord APD at the injured level and mid C5 with magnetic resonance imaging. Spinal cord compression ratio was calculated by dividing spinal cord at the injured level by spinal cord at mid C5. As the evaluation of spinal cord size relative to the dural sac, spinal cord/dural sac ratio was calculated at the injured level and mid C5. To clarify the factors influencing the severity of paralysis, the relationships between JOA score and those parameters were examined statistically.A significant negative correlation was observed between JOA score and spinal cord/dural sac ratio at mid C5. No clear relationship was observed between JOA score and bony canal APD or spinal cord compression ratio.In elderly patients with SCI caused by minor trauma, a relatively large spinal cord for the dural sac was shown to be a factor that influences the severity of paralysis. This result can be useful for the treatment and prevention of SCI in the elderly.

Individualized artificial titanium alloy spinal lamina with 3D printing technology

Background: Laminectomy and decompression is a common procedure for treating spine diseases. However, due to the lack of a posterior, bony braced structure, the dural sac and nerve roots can adhere to the surrounding tissues, and scar formation can occur in muscle and soft tissues. This can cause new compression post surgery, and failure of the operation. Objective: This study aimed to produce an individualized titanium alloy spine lamina using 3D printing technology, and to evaluate its effectiveness by implantation in human cadaveric spines. Methods: Six adult lumbar cadaver specimens were used, and computed tomography (CT) was used to obtain DICOM medical digital image standard data. The lumbar vertebrae structure was reconstructed by three-dimensional (3D) modeling software, and then simulated lumbar laminectomy was performed. Based on the characteristics of the original lamina, an artificial spine lamina was designed, including suture holes at the posterior ligament attachment point and a locking screw hole for fixation. A titanium alloy spine lamina was fabricated by 3D printing, and a guide plate to assist artificial lamina implantation was designed. Using the guide plated, L4 lumbar vertebrae segment laminectomy was performed on the 6 lumbar spine specimens, titanium alloy spine lamina were implanted and fixed with cortical bone trajectory screws. After implantation, CT was performed to record the length of the screw, the trajectory of the screw in the pedicle, and changes of bony spinal canal volume and anteroposterior diameter of the spinal canal. Results: The morphology of artificial spine lamina matched that of the original lamina. The artificial lamina was easy to implant, and matched the original lamina. The laminas were fixed by 12 cortical screws (diameter, 4.5 mm; median length, 34.67 ± 1.97 mm). CT scan indicated that all screws passed through the pedicle cortex by &lt; 2 mm (2 screws penetrated the inner wall). The bony canal volume of the L4 vertebral pedicle was 311.23 ± 38.17 mm2 before operation and 356.17 ± 43.11 mm2 after operation, and there was statistical difference (P &lt; 0.001). The anteroposterior diameter of spinal canal was 17.82 ± 2.03 mm before surgery and 20.67 ± 2.38 mm after surgery, and they were statistically different (P &lt; 0.001). Conclusion: An individualized artificial titanium alloy spine lamina designed and produced with 3D printing technology can be used to reconstruct the structure of the posterior spine complex after lumbar laminectomy. The artificial lamina can increase the volume of the spinal canal and provide a posterior ligament reconstruction attachment point.

Lumbar Canal Diameter Evaluation by CT Morphometry-Study of Indian Population.

A cross-sectional study. To document dimensions of the lumbar vertebrae and bony canal in an Indian population and to compare with other studies from the subcontinent as well as from other parts of world. An observational study was conducted on the basis of a review of thin-cut (3 mm) computed tomographic images of lumbar vertebrae. A total of 302 patients were studied, and various dimensions were analyzed. In general, the vertebral and bony spinal canal dimensions were found to be greater in male patients. Comparison of populations revealed statistically significant differences in the spinal canal between an Indian population and others. Lumbar canal stenosis is a condition in which the anteroposterior and lateral dimensions of the bony spinal canal are less than normal for corresponding age and sex. Numerous studies have been conducted to determine morphometry of the lumbar vertebrae and spinal canal, mostly in western populations, using fresh cadaver or osteologic specimens. These studies did not mention the difference between the vertebral parameters in men and women. Moreover, many of these studies have limitations such as a small sample size and lack of demographic data including race, age, and sex. In this study, we have conducted morphometric analysis of the lumbar vertebrae in a relatively large number of Indian patients by using computed tomography scan. The morphometric data thus compiled may provide a baseline of body and canal dimensions that could guide clinical experts in their practice. The dimensions of the lumbar vertebrae and bony canal thus obtained shall provide a baseline normative data for evaluation of patients presenting with low backache and lumbar canal stenosis in an Indian population.

Primitive neuroectodermal tumor of spine - A case report

Primitive neuroectodermal tumors (PNETs) are malignant soft tissue tumors of uncertain origin. They usually occur in the deep soft tissues. PNET of the spine are rare. We herein report a case of PNET occurring in thoracic region in an adult male. A 44-year-old male presented with acute onset lower extremity weakness and urinary retention. Magnetic resonance imaging revealed a mass lesion well defined moderately homogenously enhancing extradural lesion at D6. D7 and D8 level, extending into bony spinal canal and left neural foramina causing their widening at D6 and D7 level. On examination patient was conscious and oriented, higher mental functions are normal, cranial nerves normal. Paraplegia was seen with bowel and bladder fully involved. There was no sensation below D6 level. Deep tendon reflexes were absent. The patient’s neurological examination improved dramatically after the surgery. The histopathological and immunohistochemical evaluations revealed PNET. Surgery remains the treatment of choice and immunohistochemistry is required for confirming the diagnosis. Keywords: Primitive neuroectodermal tumor, Extradural, Thoracic region, Paraplegia.

Novel compression rat model for developmental spinal stenosis.

Developmental spinal stenosis (DSS) is characterized by pre-existing circumferential narrowing of the bony spinal canal which predisposes neural tissue to compression. This study aims to create a reproducible animal model mimicking DSS for investigation of its pathoanatomy. Developmental spinal canal constriction was simulated using circumferential compression. Eighteen female Sprague-Dawley rats (13.0-14.5 weeks-old) underwent circumferential compression at L4-L5 using silicone sheets; or dorsal compression using overlapping silicone sheets; or as controls. A series of outcome scores were used for locomotor function assessment, together with electrophysiological and histological assessment. Assessment time-points were at preoperative, postoperative 1-week, 2-weeks, 3-weeks, 1-month, and pre-sacrifice. Statistical analyses were performed. At all postoperative time-points, circumferential group had the worst mean Basso, Beattie and Bresnahan locomotor scores with significant difference from the control group (p < 0.05), as well as the lowest mean Louisville Swim Scale scores, as compared to the dorsal (p < 0.05) and to the control (p < 0.01) groups. Circumferential group had worse mean foot fault score for both hindlimbs (p < 0.01 to p < 0.05) and highest error rate in foot placement accuracy, especially higher than dorsal (p < 0.05) and control (p < 0.05) groups at pre-sacrifice. Electrophysiological assessment revealed postoperative increase in P1 latency was higher in circumferential than dorsal compression. Highest postoperative mean P1 latency was observed for both paws at all postoperative time-points for circumferential group (except at postoperative 1-week). Circumferential group had lower myelin-to-axonal area ratio and higher g-ratio than both the dorsal and control groups (p < 0.001). For each study group, hindlimb P1 latency and P1-N1 amplitude were each correlated with g-ratio (p < 0.05); and mean myelin-to-axonal area ratio correlated with P1 latency of both hindlimbs (p < 0.05). Based on these more severe axonal demyelination and neurological deficits, a valid DSS rat model is created with somatosensory evoked potential neuro-monitoring technique. © 2019 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res.

The influence of developmental spinal stenosis on the risk of re-operation on an adjacent segment after decompression-only surgery for lumbar spinal stenosis.

The aim of this study was to determine the influence of developmental spinal stenosis (DSS) on the risk of re-operation at an adjacent level. This was a retrospective study of 235 consecutive patients who had undergone decompression-only surgery for lumbar spinal stenosis and had a minimum five-year follow-up. There were 106 female patients (45.1%) and 129 male patients (54.9%), with a mean age at surgery of 66.8 years (sd 11.3). We excluded those with adult deformity and spondylolisthesis. Presenting symptoms, levels operated on initially and at re-operation were studied. MRI measurements included the anteroposterior diameter of the bony spinal canal, the degree of disc degeneration, and the thickness of the ligamentum flavum. DSS was defined by comparative measurements of the bony spinal canal. Risk factors for re-operation at the adjacent level were determined and included in a multivariate stepwise logistic regression for prediction modelling. Odds ratios (ORs) with 95% confidence intervals were calculated. Of the 235 patients, 21.7% required re-operation at an adjacent segment. Re-operation at an adjacent segment was associated with DSS (p = 0.026), the number of levels decompressed (p = 0.008), and age at surgery (p = 0.013). Multivariate regression model (p < 0.001) controlled for other confounders showed that DSS was a significant predictor of re-operation at an adjacent segment, with an adjusted OR of 3.93. Patients with DSS who have undergone lumbar spinal decompression are 3.9 times more likely to undergo future surgery at an adjacent level. This is a poor prognostic indicator that can be identified prior to index decompression surgery.

Bioinspired Hydrogel Electrospun Fibers for Spinal Cord Regeneration

AbstractFully simulating the components and microstructures of soft tissue is a challenge for its functional regeneration. A new aligned hydrogel microfiber scaffold for spinal cord regeneration is constructed with photocrosslinked gelatin methacryloyl (GelMA) and electrospinning technology. The directional porous hydrogel fibrous scaffold consistent with nerve axons is vital to guide cell migration and axon extension. The GelMA hydrogel electrospun fibers soak up water more than six times their weight, with a lower Young's modulus, providing a favorable survival and metabolic environment for neuronal cells. GelMA fibers further demonstrate higher antinestin, anti‐Tuj‐1, antisynaptophysin, and anti‐CD31 gene expression in neural stem cells, neuronal cells, synapses, and vascular endothelial cells, respectively. In contrast, anti‐GFAP and anti‐CS56 labeled astrocytes and glial scars of GelMA fibers are shown to be present in a lesser extent compared with gelatin fibers. The soft bionic scaffold constructed with electrospun GelMA hydrogel fibers not only facilitates the migration of neural stem cells and induces their differentiation into neuronal cells, but also inhibits the glial scar formation and promotes angiogenesis. Moreover, the scaffold with a high degree of elasticity can resist deformation without the protection of a bony spinal canal. The bioinspired aligned hydrogel microfiber proves to be efficient and versatile in triggering functional regeneration of the spinal cord.

Risk factors for spinal cord injury progression after anterior fusion for cervical spine trauma: a retrospective case-control study.

Single-center, retrospective case-control study. This study aimed to determine the risk factors for progression of neurological symptoms after anterior fusion for cervical spine trauma with no or incomplete spinal cord injury. Community-based hospital with an acute care center in Japan. We retrospectively reviewed 54 consecutive unstable subaxial cervical spine fracture/dislocation cases that had undergone surgical treatment. A total of 20 patients with no or incomplete spinal cord injury who underwent anterior fusion were identified. Injury characteristics, bony spinal canal diameter (SCD) at the injured level on computed tomography (CT), diagnosis delay of more than 24 h, and other surgery-related parameters were documented as potential risk factors. The study population included 16 male and 4 female patients. The median age was 71.5 (range: 20-88) years. Two cases of SCI progression were identified (AIS E to C5-8 C and AIS D to C5-8 C). Both cases occurred in men who were older than the average age of all the patients. Only delayed diagnosis was significantly associated with the progression of SCI (p = 0.02). SCDs on CT demonstrated a tendency to be smaller than those of cases without progression, but this was not statistically significant (progression: median, 8.1 [7.2-8.9] mm; no progression: median, 10.1 [4.2-12.6] mm; p = 0.21). Our results suggested that a delay in diagnosis was associated with neurological progression after ACF. Furthermore, imposing ligamentous flavum might become a compression factor if the diagnosis is delayed.

Risk Factors for Dural Tears in Thoracic and Lumbar Burst Fractures Associated With Vertical Laminar Fractures.

Retrospective cohort study. To reveal the risk factors for dural tears in thoracic and lumbar (TL) burst fractures associated with vertical laminar fractures through multivariate analysis. Dural tears associated with laminar fractures in patients with TL burst fractures represents a special group requires distinct treatment with different surgical prognosis. It is still very difficult to predict dural tears in patients with vertical laminar fractures. The risk factors for dural tears have seldom been evaluated. Medical records of 113 patients of TL burst fractures with vertical laminar fractures were reviewed. The data were subdivided into two groups consisting of patients with and without dural tears. Demographic information, preoperative clinical, and radiological characteristics were compared between the groups. Multivariate logistic regression models were employed to determine the independent risk factors for dural tears. The incidence of dural tear was 27.4% in this retrospective cohort. When compared with the dural intact group, the dural tear group had significantly worse preoperative neurological status, wider interpedicular distance, greater separation of laminar fractures, and larger encroachment of retropulsed fragment in the bony spinal canal. Multivariate stepwise logistic regression analysis showed that the ratio of interpedicular distance greater than 125% (odds ratio = 9.5; P < 0.001) and the ratio of encroachment of retropulsed fragment in the bony spinal canal of more than 50% (odds ratio = 61.2; P < 0.001) were independent risk factors for dural tears. Patients with wider interpedicular distance and larger encroachment of retropulsed fragment in the bony spinal canal were more likely to have dural tears in TL burst fractures with vertical laminar fractures. 3.

Etiology of developmental spinal stenosis: A genome-wide association study.

Our study aimed to identify possible single nucleotide polymorphisms (SNPs) via a genome-wide association study (GWAS) approach and a candidate gene platform that were associated with lumbar developmental spinal stenosis (DSS). Southern Chinese population-based study volunteers were assessed (age range: 18-55 years). DSS was defined as the anteroposterior bony spinal canal diameter on T1-weighted axial MRI of L1 to S1. Genotyping was performed using the Illumina HumanOmniZhongHua-8 BeadChip. Using the canal diameter as the quantitative trait, genomic statistical analyses was performed. A total of 469 subjects were recruited. The mean axial AP measurements noted were: L1: 21.8 mm, L2: 21.9 mm, L3: 22.4 mm, L4: 20.2 mm, L5: 19.6 mm, and S1: 17.3 mm. Q-Q plots of genome-wide associations found significant differences in L4 and L5 measurements. More significant SNPs were found on chromosomes 8, 11, and 18. Low-density lipoprotein receptor-related protein 5 on chromosome 11 was found to be an important functional gene in canal bony development via candidate gene approach. We found two clusters in the findings with one including the upper levels (L1-L4) and the other the lower levels (L5 and S1). This is the first GWAS addressing DSS. The presence of multiple SNPs suggests a multi-factorial origin of DSS. Further analyses noted region-specific genetic predisposition, delineating distinct upper to lower lumbar regions of DSS. With better understanding of the DSS phenotype and genetic markers, the at-risk population can be identified early, preventative measures can be initiated, lifestyle/activity modification can be implemented, and more novel and precision-based therapeutics can be developed. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 36:1262-1268, 2018.

A practical radiographic visual estimation technique for the prediction of developmental narrowing of cervical spinal canal

To determine if visual spinal canal percentage of facet overlap could be used as a rapid visual pre-screening test to detect developmental bony spinal canal narrowing on lateral cervical radiographs. Lateral cervical spine radiographs with radiology report documenting developmental narrowing of the spine canal were retrospectively identified. Cohort was supplemented with additional images without such documentation. Utilizing a radiology work station, one reader (Orthopaedics) calculated the Torg ratio at C3-C6. Two readers (Radiology, Primary Care Sports Medicine) visually estimated percentage (≥80, ≥90, 100%) of spinal canal overlaid by facet articulations C3-C6 for all cases independently. Statistical analysis included accuracy tests and kappa test for comparing the gold standard and inter-, intra-observer reliability, respectively. 96 lateral images were included; 25 had abnormal radiology reports. High specificity (range, 91-93%) and true negative predictive values (range, 88-93%) achieved consistent statistical significance for relationship between facet/canal overlap and Torg ratio for both combined and individual data points. Sensitivity values (range, 59-75%) showed a trend toward association, with statistical significance for only the C3 level at 80% overlap. Interobserver agreement was substantial. Intra-observer reliability was moderate to perfect. Visual estimation of percentage of facet overlap of the spinal canal is a valid tool to identify individuals with potential developmental narrowing of the spinal canal as a screening prompt to select which patients may need formal calculation utilizing accepted metrics. Advances in knowledge Visual estimation of percentage of facet overlap from lateral radiographs can predict developmental narrowing of cervical spinal canal.

Approaches to paraspinal tumours – a technical note

Neurogenic tumours of the paraspinal space can occur in all age groups. It is common in adult population and relatively rare in elderly group. Usually they are benign, but in children, arising from the autonomic system, tends to be malignant in nature. Usually in adults, they arise from peripheral nerve sheath and are labelled as schwannomas. For a given tumour, determination of a correct surgical approach is mandatory to achieve a successful surgical outcome. Several factors like tumour size, histology, involvement of the bony spinal canal, etc. are some of the deciding factors for a correct surgical approach. Since many such tumours are benign, total excision is possible with a correct surgical approach. If the tumour involves the integrity of the spine then additionally a stabilization procedure may have to be carried out. Unfortunately, there are still no guidelines regarding the choice of surgical approach for the excision of such tumors. Presented here is a series of five patients managed by us over a period of 10 years. Four patients were adults and one female child was three years old. Four patients were operated upon successfully and the fifth one is waiting for surgery.