Foraminal Diameter Research Articles

Consistency of Radiological Grading of Cervical Foraminal Stenosis

Background:: The degree of cervical foraminal stenosis on MRI scans may be measured and categorised using the Kim or modified Kim methods. These grading scales have not previously been validated in a cohort of patients awaiting surgery. Objectives:: To establish the normal foraminal and root diameters as well as the consistency of inter and intra-rater grading using the Kim and modified Kim grading systems in pre-operative surgical patients. Methods:: Asymptomatic cervical nerve roots and foramina demonstrated on the pre-operative MRI scans of adult surgical patients with cervical radiculopathy were measured and categorised by six raters using the Kim and modified Kim grading methods. Repeat “second pass” measurements were made by the same assessors on the same images a minimum of one month later. Results:: Foraminal diameters (mm) in asymptomatic foramina were C2/C3 (mean±SD): 4.18±1.44, C3/C4 2.96±1.23, C4/C5 3.02±1.19, C5/C6 3.15±1.33, C6/C7 3.53±1.36, C7/T1 3.93±1.34. Nerve root diameters were C3 3.11±0.87, C4 2.95±0.77, C5 2.56±0.73, C6 2.26±0.76, C7 2.56±0.82, C8 3.83±0.86. Inter-rater consistency was kappa [95% CI]: Kim 0.01 [0.00, 0.03], modified Kim 0.08 [0.05, 0.10]. Intra-rater consistency was kappa [95% CI]: Kim 0.81 [0.77, 0.86], modified Kim 0.69 [0.62, 0.76]. Conclusion:: There was poor inter-rater consistency but good intra-rater consistency when assessing the severity of foraminal stenosis on axial T2 MRI scans. Foraminal diameter was narrowest at C3/C4 and C4/C5, whereas the smallest root diameter was C5/C6. Volumetric or oblique MR may improve consistency.

Additional benefit of ultrasonography to evaluate nerve root condition of degenerative cervical spine disease.

A cross-sectional explanatory study. To clarify the nerve root condition and the association between nerve root cross-sectional area (CA) on ultrasonography (US) and other examinations such as MRI or compound muscle action potentials (CMAPs) in degenerative cervical spine diseases. A university hospital in Japan. Fifty-one patients diagnosed with proximal cervical spondylotic amyotrophy (CSA) (13 patients), cervical radiculopathy of C5 or C6 nerve root (CR) (26 patients), or cervical spondylotic myelopathy (CSM) (12 patients), and twenty-nine healthy volunteers were included in this study. Neurological findings, US findings and CMAPs of deltoid and biceps muscles of all participants were evaluated. In addition, CSA, CR, and CSM patients underwent MRI. A significant correlation was not observed between CA and CMAP amplitude or foraminal diameter on MRI (P > 0.05). In the US examination, the C6 CA of the affected side of the CR group was significantly larger than that of both the normal side and the other groups (P < 0.001). The C5 CA of the affected side of the CSA group clearly showed a bimodal distribution: enlarged and small CA groups. In the CMAP findings, CSA cases respectively showed the lower amplitude of deltoid and bicep CMAPs on both the normal and the affected side (P ≦ 0.01). CSM and healthy volunteers were nearly identical in CA and CMAPs. Utilizing US in addition to NCS and MRI can contribute towards an evaluation of the nerve root condition of degenerative cervical spine disease. no sponsorship.

Comparative Analysis With Modified Inclined Technique for Posterior Endoscopic Cervical Foraminotomy in Treating Cervical Osseous Foraminal Stenosis: Radiological and Midterm Clinical Outcomes.

ObjectiveWe compared the midterm clinical and radiological outcomes between 2 types of full endoscopic posterior cervical foraminotomy, including conventional posterior endoscopic cervical foraminotomy (PECF) and modified inclined technique for PECF. MethodsOne of the 2 types of PECF surgery was performed for defined cervical foraminal stenosis. The foraminal expansion ratio and facet resection rate and foraminal stenosis grade were measured using magnetic resonance imaging. Visual analogue scale (VAS) scores for neck and arm pain, neck disability index, MacNab criteria, operation time, hospital stay, and complications, including postoperative dysesthesia, were assessed. Clinical and radiological parameters were compared between the 2 surgical groups. ResultsThere were 49 and 46 patients in the PECF and modified-PECF groups, respectively. The modified-PECF group showed significantly higher expansion of distal foraminal diameter and foraminal height, and a lower facet resection rate compared to PECF group (in all, p<0.001). The modified-PECF group displayed significantly lower VAS score for neck pain at 1 day and 1 week after surgery and lower arm pain VAS score after 6-month follow-up (p=0.002, p=0.001, p=0.002, respectively). ConclusionCompared with the PECF, the modified inclined technique has radiologic benefits, including enhanced facet joint preservation, restoration of the natural course of nerve roots, and prevention of restenosis by expanding the superior articular process base, especially in grade 2 foraminal stenosis. Furthermore, the modified inclined technique significantly improved the postoperative VAS score for neck pain within the 1-week follow-up and that of arm pain after 6-month follow-up.

Solids retention time dependent, tunable diatom hierarchical micro/nanostructures and their effect on nutrient removal

The hierarchical three-dimensional (3D) micro/nanostructures of diatoms make them a promising biomaterial for fabricating nanomaterials, producing bioactive pharmaceuticals or nutraceuticals, and removing micropollutants. For diatom production in a continuous flow system, little is known how bioreactor operating parameters, especially solids retention time (SRT), affect the 3D structures of diatoms. This study demonstrated that tunable diatom micro/nanostructures could be produced by varying the SRT of membrane bioreactors (MBRs). A diatom strain (Stephanodiscus hantzschii) was cultivated in two identical MBRs with a fixed hydraulic retention time (HRT) of 24 h and staged SRTs from 5, to 10, and to 20 d. As SRTs increased from 5 to 20 d, important characteristics of diatom micro/nanostructures showed linear decreases: the diameters of foramina on the areola layer decreased from 170 ± 10 to 130 ± 12 nm, the numbers of nanopores per cribrum layer decreased from 20 ± 3 to 12 ± 2, and the specific surface areas of the diatoms decreased from 36.01 ± 1.27 to 12.67 ± 2.45 m2·g−1. However, the average diatom heights increased from 2.9 ± 0.3 to 3.9 ± 0.4 µm, while diatom cell diameter (5 µm) and nanopore size (20 nm) remained unchanged. The silicon content of diatoms also linearly increased with SRT. The decrease in diatom porosity and increase in silicon content were probably due to the reduced diatom growth rates (likely resulting in less pores) at increasing SRTs, which also facilitated silica deposition as the overall diatom population stayed longer in the MBRs. As the SRTs increased from 5 to 10, and to 20 d, the nitrate (NO3−) removal efficiency decreased from 75% to 70%, and to 60%, respectively, whereas phosphorus (P) removal efficiency increased from 74% to 80%, and to 90%, respectively. The opposite trends in efficiencies were because NO3−-N was removed by cellular uptake and biomass waste whereas P was mainly removed through diatom-assisted chemical precipitation.

Análise clínica do diâmetro do forame dos molares de acordo com a faixa etária e diagnóstico pulpar e perirradicular

Introdução: A compreensão das características do diâmetro foraminal contribui para o trabalho do clínico pois permite a seleção dos instrumentos apropriados para o preparo dos canais radiculares. O objetivo deste trabalho foi avaliar o diâmetro foraminal, in vivo, em canais de molares superiores e inferiores e verificar a influência de fatores como faixa etária e diagnóstico pulpar e perirradicular. Métodos: 150 canais radiculares de 48 primeiros e segundos molares superiores e inferiores, foram divididos em grupos de acordo com a faixa etária: A1 - Menores de 15 anos; A2 - 16 a 34 anos e A3 - 34 a 50 anos, e de acordo com o diagnóstico: Pulpite irreversível; necrose pulpar e necrose pulpar com periodontite apical assintomática. Limas tipo K foram inseridas até o comprimento real do dente (CRD) para a seleção do instrumento anatômico foraminal (IAF). O diâmetro inicial da ponta (D0) do IAF foi considerado para a determinação do diâmetro foraminal. Os dados foram analisados por meio da análise de variância a três critérios e para as comparações múltiplas empregou-se o teste de Tukey. Resultados: Houve diferença estatística significante na interação entre faixa etária e diagnóstico (p &lt; 0.001), sendo que dentes de pacientes mais jovens (A1) com pulpite irreversível apresentaram maiores diâmetros. Ainda, verificou-se que, independente da faixa etária e do diagnóstico, o diâmetro foi significativamente influenciado pelo tipo de dente/canal (p &lt; 0.001). Conclusão: O diâmetro foraminal pode variar conforme o tipo de dente/canal radicular, sendo que faixa etária e diagnóstico também influenciam os resultados quando analisados concomitantemente.

Three-dimensional computed tomographic evaluation of lateral lumbar interbody fusion: morphometric change of intervertebral structure.

Two-dimensional (2D) analyses of intervertebral disc (IVD) height and foramen measurements following lateral lumbar interbody fusion (LLIF) have been reported. However, three-dimensional (3D) morphometric analysis of intervertebral structure using 3D computed tomography (3D CT) provides increased precision for measuring morphological changes. The purpose of this study was to evaluate 3D changes of lumbar IVD height and foramen diameter in degenerative lumbar disease patients following LLIF. Subject-based 3D CT lumbar models were created for 26 patients before and following LLIF. IVD height (whole and five anatomical zones) and foramen diameter (minimum and maximum) were measured based on the model using custom software. The sagittal placement of cages (SPC) and cross-sectional area of the thecal sac (CSA) were measured. Changes in these parameters by LLIF were quantified and statistically analysed. Following LLIF, disc height increased by an average of 2.9mm (P < 0.01). Post-operative measurements of both minimum and maximum diameters of the foramen were significantly increased by 1.0mm and 1.9mm, respectively (P < 0.01). Change in maximum foramen diameter was significantly correlated with change in disc height (P < 0.05). The SPC was significantly correlated with the changes in disc height and foraminal diameters (P < 0.05, respectively). No significant change between the change in disc height and CSA was found. This preliminary study quantifies disc height and foramen diameter changes in 3D following LLIF. The presented data provide baseline intervertebral changes for future comparisons with follow-up studies and clinical outcomes. Diagnostic: individual cross-sectional studies with the consistently applied reference standard and blinding.

Evaluation of apical transportation and apical root sealing in root canals prepared with mtwo rotary system with and without apical enlargement – an in vitro study

The aim of this study was to evaluate apical transportation and apical root canal sealing after root canal filling in human teeth prepared with MTwo® Rotary System with and without apical foramen enlargement. Twenty mandibular premolars were divided into two groups (n=10). Group 1 had root canals prepared 1mm beyond the apical foramen. Group 2 had root canals prepared 1mm below the root canal length. After chemo-mechanical preparation, samples were submitted to scanning electronic microscopy. Apical foramen images had 75x magnification at standardized positions, allowing measurements from the apical foramen area before and after root canal preparation, and after root canal filling. Apical foramen shape and apical transportation, as well as its level of circumferential filling after root canal preparation were accessed using the Image Subtraction System. Scanning electronic microscopy analysis demonstrated that samples of Group 1 showed larger foraminal diameter than samples of Group 2 (p&lt;0.05). Apical foramen transportation was statistically different between Groups 1 and 2 (p=0.0108). Furthermore, the apical foramen sealing also differed statistically between groups 1 and 2 (p=0.0007) and 100% of samples of Group 1 showed apical root canal sealing. Apical root canal sealing was more effective when the root canal was prepared with apical foramen enlargement, even when the apical transportation was detected.

In vivo 3D tomography of the lumbar spine using a twin robotic X-ray system: quantitative and qualitative evaluation of the lumbar neural foramina in supine and upright position

ObjectivesSupine lumbar spine examinations underestimate body weight effects on neuroforaminal size. Therefore, our purpose was to evaluate size changes of the lumbar neuroforamina using supine and upright 3D tomography and to initially assess image quality compared with computed tomography (CT).MethodsThe lumbar spines were prospectively scanned in 48 patients in upright (3D tomographic twin robotic X-ray) and supine (30 with 3D tomography, 18 with CT) position. Cross-sectional area (CSA), cranio-caudal (CC), and ventro-dorsal (VD) diameters of foramina were measured by two readers and additionally graded in relation to the intervertebral disc height. Visibility of bone/soft tissue structures and image quality were assessed independently on a 5-point Likert scale for the 18 patients scanned with both modalities. Descriptive statistics, Wilcoxon’s signed-rank test (p < 0.05), and interreader reliability were calculated.ResultsNeuroforaminal size significantly decreased at all levels for both readers from the supine (normal intervertebral disc height; CSA 1.25 ± 0.32 cm2; CC 1.84 ± 0.24 cm2; VD 0.88 ± 0.16 cm2) to upright position (CSA 1.12 ± 0.34 cm2; CC 1.78 ± 0.24 cm2; VD 0.83 ± 0.16 cm2; each p < 0.001). Decrease in intervertebral disc height correlated with decrease in foraminal size (supine: CSA 0.88 ± 0.34 cm2; CC 1.39 ± 0.33 cm2; VD 0.87 ± 0.26 cm2; upright: CSA 0.83 ± 0.37 cm2, p = 0.010; CC 1.32 ± 0.33 cm2, p = 0.015; VD 0.80 ± 0.21 cm2, p = 0.021). Interreader reliability for area was fair to excellent (0.51–0.89) with a wide range for cranio-caudal (0.32–0.74) and ventro-dorsal (0.03–0.70) distances. Image quality was superior for CT compared with that for 3D tomography (p < 0.001; κ, CT = 0.66–0.92/3D tomography = 0.51–1.00).ConclusionsThe size of the lumbar foramina is smaller in the upright weight-bearing position compared with that in the supine position. Image quality, especially nerve root delineation, is inferior using 3D tomography compared to CT.Key Points• Weight-bearing examination demonstrates a decrease of the neuroforaminal size.• Patients with higher decrease in intervertebral disc showed a narrower foraminal size.• Image quality is superior with CT compared to 3D tomographic twin robotic X-ray at the lumbar spine.

Molecular Basis for Craniofacial Phenotypes Caused by Sclerostin Deletion

Some genetic disorders are associated with distinctive facial features, which can aid in diagnosis. While considerable advances have been made in identifying causal genes, relatively little progress has been made toward understanding how a particular genotype results in a characteristic craniofacial phenotype. An example is sclerosteosis/van Buchem disease, which is caused by mutations in the Wnt inhibitor sclerostin (SOST). Affected patients have a high bone mass coupled with a distinctive appearance where the mandible is enlarged and the maxilla is foreshortened. Here, mice carrying a null mutation in Sost were analyzed using quantitative micro–computed tomographic (µCT) imaging and histomorphometric analyses to determine the extent to which the size and shape of craniofacial skeleton were altered. Sost−/− mice exhibited a significant increase in appositional bone growth, which increased the height and width of the mandible and reduced the diameters of foramina. In vivo fluorochrome labeling, histology, and immunohistochemical analyses indicated that excessive bone deposition in the premaxillary suture mesenchyme curtailed overall growth, leading to midfacial hypoplasia. The amount of bone extracellular matrix produced by Sost−/− cells was significantly increased; as a consequence, osteoid seams were evident throughout the facial skeleton. Collectively, these analyses revealed a remarkable fidelity between human characteristics of sclerosteosis/van Buchem disease and the Sost−/− phenotype and provide clues into the conserved role for sclerostin signaling in modulating craniofacial morphology.

The F2RaD Score: A Novel Prediction Score and Calculator Tool to Identify Patients at Risk of Postoperative C5 Palsy.

Postoperative C5 palsy is a debilitating complication following posterior cervical decompression. To create a simple clinical risk score predicting the occurrence of C5 palsy. We retrospectively reviewed all patients who underwent posterior cervical decompressions between 2007 and 2017. Data was randomly split into training and validation datasets. Multivariable analysis was performed to construct the model from the training dataset. A scoring system was developed based on the model coefficients and a web-based calculator was deployed. The cohort consisted of 415 patients, of which 65 (16%) developed C5 palsy. The optimal model consisted of: mean C4/5 foraminal diameter (odds ratio [OR] = 9.1 for lowest quartile compared to highest quartile), preoperative C5 radiculopathy (OR=3.5), and dexterity loss (OR=2.9). The receiver operating characteristic yielded an area under the curve of 0.757 and 0.706 in the training and validation datasets, respectively. Every characteristic was worth 1 point except the lowest quartile of mean C4/5 foraminal diameter, which was worth 2 points, and the factors were summarized by the acronym F2RaD. The median predicted probability of C5 palsy increased from 2% in patients with a score of 0 to 70% in patients with a score of 4. The calculator can be accessed on https://jhuspine2.shinyapps.io/FRADscore/. This study yielded a simplified scoring system and clinical calculator that predicts the occurrence of C5 palsy. Individualized risk prediction for patients may facilitate better understanding of the risks and benefits for an operation, and better prepare them for this possible adverse outcome. Furthermore, modifying the surgical plan in high-risk patients may possibly improve outcomes.

Predicting Unilateral Post-laminectomy C5 Palsy by Measuring C5 Exit Foramen Area on Preoperative Computed Tomography

Background and aim: Postoperative C5 motor palsy is known as a common complication, not only after cervical laminectomy but also after anterior discectomy. There is no consensus on any of the proposed mechanisms of C5 palsy following posterior cervical decompression. It was found that C5 palsy is more common in patients with smaller C5 root foramen area. The purpose of this study was to define a cut-off value for C4-C5 foraminal area on preoperative computed tomography images to predict post-laminectomy C5 palsy. Methods and Materials/Patients: In this prospective clinical study, C4-C5 foraminal area of 119 patients with cervical spondylotic myelopathy calculated on reformatted pure sagittal computed tomography images value was defined by measuring maximal height and transverse diameter of foramina and a cut-off in which with lesser amounts, post-laminectomy C5 palsy was more common. Results: Of 119 patients with spondylotic myelopathy undergoing cervical laminectomy,23 ones experienced postoperative C5 palsy with mean C4-C5 foraminal area of 44.54±0.72 mm2.Mean C5 root exit foraminal area in patients with intact post-operative root function was calculated 56.78±5.48 mm2 and the difference between these two groups was statistically significant (P&lt;0.05). No patient with C5 exit foraminal area more than 46 mm2had C5 palsy after laminectomy. Conclusion: The incidence of post-laminectomy C5 palsy is significantly higher in patients with C5 exit foraminal area less than 46 mm2. Prophylactic C4-C5 foraminotomy in this group may significantly reduce the risk of postoperative C5 nerve motor palsy, although the effect of this procedure is still debatable.

Factors Associated With C5 Palsy Following Cervical Spine Surgery: A Systematic Review.

Study Design:Systematic review.Objectives:C5 palsy (C5P) is a not uncommon and disabling postoperative complication with a reported incidence varying between 0% and 30%. Among others, one explanation for its occurrence includes foraminal nerve root tethering. Although different risk factors have been reported, controversy about its causation and prevention persists. Inconsistent study findings contribute to the persistent ambiguity leading to an assumption of a multifactorial nature of the underlying C5P pathophysiology. Here, we report the results of a systematic review on C5P with narrow inclusion criteria in the hope of elucidating risk factors for C5P due to a common pathophysiological mechanism.Methods:Electronic databases from inception to March 9, 2019 and references of articles were searched. Narrow inclusion criteria were applied to identify studies investigating demographic, clinical, surgical, and radiographic factors associated with postoperative C5P.Results:Sixteen studies were included after initial screening of 122 studies. Eighty-four risk factors were analyzed; 27 in ≥2 studies and 57 in single studies. The pooled prevalence of C5P was 6.0% (range: 4.2%-24.1%) with no consistent evidence that C5P was associated with demographic, clinical, or specific surgical factors. Of the radiographic factors assessed, specifically decreased foraminal diameter and preoperative cord rotation were identified as risk factors for C5P.Conclusion:Although risk factors for C5P have been reported, ambiguity remains due to potentially multifactorial pathophysiology and study heterogeneity. We found foraminal diameter and cord rotation to be associated with postoperative C5P occurrence in our meta-analysis. These findings support the notion that factors contributing to, and acting synergistically with foraminal stenosis increase the risk of postoperative C5P.

Spinal cord float back is not an independent predictor of postoperative C5 palsy in patients undergoing posterior cervical decompression

BACKGROUNDOf the more than 30,000 posterior cervical spine fusions performed annually, 7%–12% will be complicated by postoperative C5 palsy, a condition characterized by new-onset deltoid weakness with or without C5 dermatomal findings and biceps weakness. Posterior translation of the cervical spinal cord has been proposed as a risk factor for this complication. PURPOSETo evaluate if C5 palsy can be predicted by spinal cord float back. STUDY DESIGN/SETTINGRetrospective cohort. PATIENT SAMPLEPatients ≥18 years of age undergoing posterior cervical decompression between 2002 and 2017 for degenerative cervical spine pathologies. OUTCOME MEASURESOccurrence of C5 palsy as evaluated by manual motor testing (MMT). METHODSWe recorded baseline neurological status, operative notes, details of postoperative course, and both pre- and postoperative magnetic resonance imaging images. Float back was defined by the change in the distance between the spinal cord and posterior face of the C4/5 annulus from preoperative to postoperative imaging. C5 palsy was defined by new-onset deltoid weakness on MMT. RESULTSWe identified 242 patients with a mean age of 62.4 years and mean follow-up of 27.9 months. Forty-two (17.4%) experienced postoperative C5 palsy. On univariable analysis, significant predictors of postoperative C5 palsy were mean C4/5 foraminal diameter (2.8 vs. 3.2 mm; p<.001), anterior projection of the C5 superior articular process (4.12 vs. 3.70 mm; p=.04), cord float back (0.35 vs. 0.28 cm; p=.02), undergoing laminectomy of the C5 (p=.02) or C4 and C5 levels (p=.02), and undergoing instrumented fusion extending one level above and below the C4/5 level. Foraminotomy of the C4/5 level was not predictive of postoperative palsy. On multivariable analysis mean C4/5 foraminal diameter (odds ratio=0.38 per mm; p<.01) predicted C5 palsy; cord float back at the C4/5 level was not predictive of C5 palsy. CONCLUSIONSSpinal cord float back was not an independent predictor of C5 palsy on multivariable analysis. Only smaller foraminal diameter was independently predictive of postoperative C5 palsy. This suggests that chronic preoperative compression of the C5 roots, not postdecompression float back may be the biggest contributor to the etiology of postoperative C5 palsy.

Quantitative radiographic analysis of foraminal re-stenosis after posterior cervical foraminotomy with laminoplasty

Few studies have performed detailed radiographic evaluation of the cause of recurrent cervical radiculopathy. In this study, we aimed to perform quantitative analyses of foraminal re-stenosis after posterior cervical foraminotomy (PCF) concomitant with laminoplasty. Seventy-eight consecutive patients (50 males and 28 females, mean age of 62 years at surgery) with cervical spondylotic radiculomyelopathy who underwent PCF concomitant with open-door laminoplasty were included. A total of 133 foramina undergoing PCF were radiographically evaluated using the following parameters: disc height, focal range of motion at the corresponding disc level, foraminal diameter (FD) and facet joint width (FJW) in the axial view on computed tomography, and re-stenosis rate (RR) of foramina. RR was calculated as follows: (foraminal regrowth at 2 years after surgery)/(foraminal enlargement immediate postoperatively) × 100% (RR2y). FDs preoperatively, postoperatively, and at 2-year follow-up were 2.2, 6.6, and 4.6 mm, respectively, and FJWs were 14.5, 9.0, and 10.6 mm, respectively. Both parameters significantly increased at the 2-year follow-up (p < 0.001). The mean RR2y was 42% (range, −16 to 108%). On logistic regression analysis of risk factors for higher RR2y (>50%), only preoperative posterior disc height (PDH) (OR = 0.33; 95% CI = 0.193–0.563; p < 0.001) was identified. Receiver operating characteristic curve analysis showed that the cut-off value of RR2y 50% was 1-mm PDH (AUC 0.73, sensitivity 52%, specificity 86%, p value < 0.001). After posterior foraminotomy with laminoplasty, the enlarged foraminal space gradually decreased during the 2-year follow-up. Foraminal re-stenosis was mainly due to bone regrowth of the resected facet joint, which is caused by disc degeneration with loss of PDH.

Preoperative Clinical and Radiographic Variables Predict Postoperative C5 Palsy

Postoperative C5 palsy affects 8% of patients undergoing posterior cervical decompression. It is associated with a period functional disability that may exceed 12 months and increase direct care costs > $2000. All patients undergoing posterior cervical decompression at a single tertiary-care facility for degenerative conditions were evaluated for preoperative imaging, clinical presentation, surgical operation, and postoperative course. We sought to identify those variables predictive of postoperative C5 palsy. Of 221 included patients (mean age, 63 years; 54% male), 12.2% experienced C5 palsy. On univariate analysis, C5 palsy was associated with foraminal diameter (P= 0.0005), spinal cord cross-sectional area (P= 0.11), number of levels undergoing laminectomy (P= 0.14), and clinical presentation of dropping objects (P= 0.07), hand clumsiness (P= 0.13), or paresthesias in the upper extremities (P= 0.08). Foraminal diameter (odds ratio, 0.31 per mm increase; 95% confidence interval, 0.16-0.60; P < 0.001) and patient report of gait disturbance (odds ratio, 0.53; 95% confidence interval, 0.33-0.85; P= 0.008) were the only significant predictors on multivariate analysis. A foraminal diameter <2 mm had 2-fold greater odds of postoperative C5 palsy. A receiver operating curve for the multivariate logistic model had an associated C-statistic of 0.7818. The absolute error of this model was 9.3% on internal validation. Foraminal stenosis most strongly predicted postoperative C5 palsy. A proof-of-concept model incorporating foramen size, as well as clinical complaints of paresthesias, hand clumsiness, and gait abnormality, successfully predicts the occurrence of postoperative palsy with an overall accuracy of 78%.

The Relationship amongst Intervertebral Disc Vertical Diameter, Lateral Foramen Diameter and Nerve Root Impingement in Lumbar Vertebra

Introduction: The vertical diameter of the foramen is dependent upon the vertical diameter of the corresponding intervertebral disc. A decrease in disc vertical diameter has direct anatomic consequences to the foraminal diameter and area available for the nerve root passing through it. This study is to establish the relationship amongst the intervertebral disc vertical diameter, lateral foramen diameters and nerve root compression in the lumbar vertebra.Materials and Methods: Measurements of the study parameters were performed using sagittal MRI images. The parameters studied were: intervertebral disc vertical diameter (DVD), foraminal vertical diameter (FVD), foraminal transverse diameter (FTD) and nerve root diameter (NRD) of both sides. The relationship between the measured parameters were then analyzed.Results: A total of 62 MRI images were available for this study. Statistical analysis showed moderate to strong correlation between DVD and FVD at all the lumbar levels except at left L23 and L5S1 and right L3L4 and L4L5. Correlation between DVD and FTD were not significant at all lumbar levels. Regression analysis showed that a decrease of 1mm of DVD was associated with 1.3, 1.7, 3.3, 3.3 and 1.3mm reduction of FVD at L1L2, L2L3, L3L4, L4L5 and L5S1 respectively.Conclusion: Reduction of DVD was associated with reduction of FVD. However, FVD was relatively wide for the nerve root even with complete loss of DVD. FTD was much narrower than the FVD making it more likely to cause nerve root compression at the exit foramina. These anatomical details should be given consideration in treating patients with lateral canal stenosis.

The Clinical Usefulness of Preoperative Imaging Studies to Select Pathologic Level in Cervical Spondylotic Myelopathy: Comparative Analysis of Three-Position MRI and Post-Myelographic CT.

To compare the accuracy of determining pathologic segment between three-position MRI (3P-MRI) and post-myelographic CT (PMCT) in cervical spondylotic myelopathy (CSM) by assessing the degree of inter-observer and intra-observer agreement. We retrospectively reviewed 3P-MRI and PMCT for the diagnosis of multilevel CSM in 136 patients who underwent surgery. Using an assessment scale, 8 blind observers with various clinical experiences examined 5 parameters: spinal canal narrowing, foraminal stenosis, bony abnormality, intervertebral disc herniation, and nerve root compression. Spinal canal, neural foraminal, spinal cord and disc protrusion diameters were measured. Intra-observer and inter-observer agreement of each image was analyzed. Spinal canal width and foraminal diameter was found to be significantly smaller in 3P-MRI compared to PMCT. No significant differences of cervical cord diameter and the size of disc protrusion measured in 3P-MRI compared to PMCT were observed. Comparing between 3P-MRI and PMCT, disc abnormality and nerve root compression showed better agreement on 3P-MRI, whereas foraminal stenosis and bony lesion showed better agreement on PMCT. In the present study, PMCT was still useful in diagnosis of the foraminal stenosis and bony lesion compared to 3P-MRI but showed limitation in disc abnormality and nerve root compression. Even though PMCT may provide valuable additional information in difficult or ambiguous cases, universal standard of 3P-MRI showed higher reliability in detecting pathologic levels in CSM patients.

Short-term clinical outcome and radiographic assessment of indirectly decompression of oblique lateral interbody fusion for degenerative lumbar spinal stenosis

Objective To investigate the short-term clinical outcome and radiographic assessment of Oblique Lateral Interbody Fusion to indirectly decompress for the degenerative lumbar spinal stenosis with or without lumbar spine instability. Methods All of 15 patients with diagnosis of degenerative lumbar spinal stenosis with or without lumbar spine instability (7 males and 8 females, age from 36y to 86, mean age 53.5±15.2 y) were treated with OLIF surgery in our spine surgery center. The main symptoms included lumbar pain with unilateral or bilateral leg pain or intermittent claudication. The Visual analogue scale (VAS), Oswestry disability index (ODI), Japanese Orthopaedic Association (JOA) and SF-36 scores were used to assess the clinical effect pre and post-operatively while radiographic assessments were compared as well as comprehensive evaluation of the radiography, MRI, and CT images. Results All patients were followed up for an average of 12.5 (6-21) months. And all the patients enjoyed alleviation of symptoms although varying in extent. The radiographic results showed satisfactory indirect decompression of the neuro-elements, as well as reduction of the lumbar spine. The DH, VH and FH increased by 3.6mm, 4.8mm and 5.7mm respectively. The foraminal area (FA) and canal area (CA) enlarged by 44.2mm2 and 24.8mm2. The canal diameters (CD) and disk-flavum ligamentum space (DLFS) increased by 2.5mm and 2mm respectively. The foraminal diameters (FD) increased by 0.3mm, but there was not significantly different. The segment angle and lumbar lordosis angle were partially restored after operation, and the angle increased by 14 ° and 13.6 °respectively. One of the patients had a transient paresthesia and mild weakness of muscle when hip flexor and recovered within 3 months. Another one case encountered serious back pain after a month and alleviated after reoperation with PPF. Conclusion OLIF can provide a satisfactory outcome for the patients with degenerative lumbar spinal stenosis through indirectly decompression, which can increase the disc height, foramen height, canal diameter and disk-flavum ligamentum space. Key words: Lumbar vertebrae; Spinal stenosis; Spinal fusion

C5 nerve palsy after posterior reconstruction surgery: predictive risk factors of the incidence and critical range of correction for kyphosis.

It has been reported that the incidence of post-operative segmental nerve palsy, such as C5 palsy, is higher in posterior reconstruction surgery than in conventional laminoplasty. Correction of kyphosis may be related to such a complication. The aim of this study was to elucidate the risk factors of the incidence of post-operative C5 palsy, and the critical range of sagittal realignment in posterior instrumentation surgery. Eighty-eight patients (mean age 64.0years) were involved. The types of the disease were; 33 spondylosis with kyphosis, 27 rheumatoid arthritis, 17 athetoid cerebral palsy and 11 others. The patients were divided into two groups; Group P: patients with post-operative C5 palsy, and Group NP: patients without C5 palsy. The correction angle of kyphosis, and pre-operative diameter of C4/5 foramen on CT were evaluated between the two groups. Multivariate logistic regression analysis was used to determine the critical range of realignment and the risk factors affecting the incidence of post-operative C5 palsy. Seventeen (19.3%) of the 88 patients developed C5 palsy. The correction angle of kyphosis in Group P (15.7°) was significantly larger than that in Group NP (4.5°). In Group P, pre-operative diameters of intervertebral foramen at C4/5 (3.2mm) were significantly smaller than those in Group NP (4.1mm). The multivariate analysis demonstrated that the risk factors were the correction angle and pre-operative diameter of the C4/5 intervertebral foramen. The logistic regression model showed a correction angle exceeding 20° was critical for developing the palsy when C4/5 foraminal diameter reaches 4.1mm, and there is a higher risk when the C4/5 foraminal diameter is less than 2.7mm regardless of any correction. This study has indicated the risk factors of post-operative C5 palsy and the critical range of realignment of the cervical spine after posterior instrumented surgery.

Clinical outcomes following sublaminar decompression and instrumented fusion for lumbar degenerative spinal pathology

Traditional treatment for lumbar stenosis with instability is laminectomy and posterolateral arthrodesis, with or without interbody fusion. However, laminectomies remove the posterior elements and decrease the available surface area for fusion. Therefore, a sublaminar decompression may be a preferred approach for adequate decompression while preserving bone surface area for fusion. A retrospective review of 71 patients who underwent sublaminar decompression in conjunction with instrumented fusion for degenerative spinal disorders at a single institution was performed. Data collected included demographics, preoperative symptoms, operative data, and radiographical measurements of the central canal, lateral recesses, and neural foramina, and fusion outcomes. Paired t-tests were used to test significance of the outcomes. Thirty-one males and 40 females with a median age 60years underwent sublaminar decompression and fusion. A median of two levels were fused. The mean Visual Analog Scale pain score improved from 6.7 preoperatively to 2.9 at last follow-up. The fusion rate was 88%, and the median time to fusion was 11months. Preoperative and postoperative mean thecal sac cross-sectional area, right lateral recess height, left lateral recess height, right foraminal diameter, and left foraminal diameter were 153 and 209mm2 (p<0.001), 5.9 and 5.9mm (p=0.43), 5.8 and 6.3mm (p=0.027), 4.6 and 5.2mm (p=0.008), and 4.2 and 5.2mm (p<0.001), respectively. Sublaminar decompression provided adequate decompression, with significant increases in thecal sac cross-sectional area and bilateral foraminal diameter. It may be an effective alternative to laminectomy in treating central and foraminal stenosis in conjunction with instrumented fusion.