Central Canal Area Research Articles

The Role of Cage Placement Angle in Optimizing Short-Term Clinical Outcomes in Lateral Lumbar Interbody Fusion

OBJECTIVEThe purpose is to investigate the impact of cage angle on clinical outcomes and indirect decompression efficacy in patients undergoing lateral lumbar interbody fusion (LLIF). METHODSA retrospective review was conducted on 87 patients with single-level lumbar degenerative disease (LDD) who underwent LLIF. Patients were grouped based on the angle of cage placement: minimal (0°-5°), mild (>5° ≤ 15°), and severe (>15°). Clinical outcomes assessed included pain intensity, functional improvement, and complication rates. Magnetic resonance imaging (MRI) evaluations included measurements of canal diameter (CD) and central canal area (CCA) pre- and postoperatively. Patient-reported outcomes were also analyzed using the Japanese Orthopaedic Association Back Pain Evaluation Questionnaire (JOABPEQ). RESULTSClinical and radiographic outcomes were significantly improved across all cage angle groups. Reductions in low back pain, leg pain, and numbness were significant in all groups, with no significant differences. MRI evaluations revealed significant increases in CD and CCA postoperatively, confirming effective indirect decompression. JOABPEQ scores showed significant improvements in all domains, including low back pain, lumbar function, walking ability, social life function, and mental health. However, the severe angle group had higher rates of delayed cage subsidence (DCS). Complications such as transient motor weakness, thigh pain, numbness, and the need for revision surgery were consistent across groups, with no significant differences. CONCLUSIONSLLIF effectively treats LDD patients, providing significant short-term clinical and radiographic improvements regardless of cage angle. However, oblique cage placement increases the risk of cage subsidence, requiring careful surgical planning and postoperative following.

Assessment of Anteroposterior Diameter and Interpedicular Distance in the Approximation of Cervical Spinal Canal Area.

Rationale and objectives This study seeks to generate a model based on two linear measurements, anteroposterior (AP) diameter and interpedicular (IPD) distance, to approximate the cervical central canal (CCC) area in a non-pathologic patient population by employing area calculations of shapes such as ellipse, rectangle, and triangle. Secondarily, this study aims to generate second-order approximations (SOAs), using the aforementioned shape approximations, to increase the utility of this linear measurement-based model. Methods The authors reviewed medical and radiographic records of patients aged 18-35 who received computed tomography (CT) imaging of the cervical spine to collect AP diameter, IPD distance, and area of the CCC from C2-3 to C6-7. Subsequently, shape approximations were calculated for each patient at all cervical spine levels. Lastly, SOAs were generated by combining optimal ratios of shape approximations to improve the statistical reliability of approximations. Results The ellipse shows the closest approximation to manual measurements of the individual shape approximations. Percent error analysis demonstrated the superiority of the ellipse, followed by the rectangle, and lastly the triangular approximation. The highest correlation of approximations was observed at C6-7. All individual shape approximations demonstrated statistical differences from manual measurements. SOAs combining ellipse and rectangle measurements demonstrated superior accuracy and were not statistically different from manual measurements. Conclusion Individual shape approximations based on AP diameter and IPD distance show some value as a model for the assessment of the CCC area. SOAs demonstrated greater utility than individual shape approximations and show promise as a linear measurement-based tool to assess the CCC area.

Comprehensive Assessment of Indirect Decompression Through Lateral Lumbar Interbody Fusion for Degenerative Lumbar Spinal Stenosis: A Japanese Orthopedic Association Back Pain Evaluation Questionnaire-Based Analysis.

A retrospective study. This study aimed to comprehensively evaluate the clinical outcomes of lateral lumbar interbody fusion (LLIF) as an indirect decompression technique for degenerative spondylolisthesis (DS) and concomitant degenerative lumbar spinal stenosis (DLSS) patients. We utilized the Japanese Orthopedic Association Back Pain Evaluation Questionnaire (JOABPEQ) to assess treatment success and its impact on patient's quality of life (QOL). We included 124 patients who underwent LLIF. Pre- and postoperative JOABPEQ evaluations indicated treatment success. Subgroup analysis categorized patients' perceptions of surgery as beneficial or non-beneficial. 89% of patients (110/124) reported satisfaction with LLIF. Lateral lumbar interbody fusion achieved successful indirect decompression, increasing canal diameter and central canal area. Significant improvements occurred across all JOABPEQ domains, notably for low back pain, lumbar function, walking ability, social life function, and mental health. Patients who perceived the surgery as beneficial experienced fewer postoperative complications, lower numeric rating scale scores for pain relief, and greater functional outcome improvements compared to non-beneficial patients. Our findings highlight the utility of JOABPEQ as a valuable and sensitive tool for assessing treatment effectiveness and patient-reported outcomes in DS and concomitant DLSS patients. Patients undergoing LLIF. The results affirm the favorable outcomes of LLIF as a surgical option for DLSS patients and emphasize the importance of considering patient perspectives when evaluating overall treatment success. The study provides valuable insights into the impact of indirect decompression on patients' QOL, supporting the effectiveness of LLIF as a minimally invasive technique for DLSS and DS management.

The Analysis of Preoperative Roussouly Classification on Pain Scores and Radiological Data in Lateral Lumbar Interbody Fusion for Patients with Lumbar Degenerative Disease

A retrospective observational study. The type of sagittal profile defined by Roussouly has affected spinal degeneration and surgical outcome. This study aimed to investigate the effect of preoperative Roussouly classification on pain intensity and radiological data of patients with lumbar degenerative disease who underwent indirect decompression with lateral lumbar interbody fusion (LLIF). We retrospectively investigated 102 patients who underwent LLIF without direct decompression. Patients were subdivided into 4 groups according to the Roussouly classification determined from preoperative full-length and lateral spine X-rays, and classified according to Roussouly types I, II, and IV in the nonstandard group and Roussouly type III in the standard group. The nonstandard group showed improved sagittal vertical axis and lumbar lordosis after LLIF surgery, but the midsagittal canal diameter and axial central canal area of the thecal sac using T2-weighted sagittal and axial magnetic resonance imaging were smaller than those in the standard group. On the other hand, each numeric rating scale score 1year after surgery improved in all patients. Changes in numeric rating scale scores in low back pain, leg pain, and numbness were not statistically significant between Roussouly classification types. These results suggest that the nonstandard group may have less indirect decompression effect from LLIF than the standard group. In the short term, we show for the first time after LLIF surgery that preoperative sagittal spinal alignment and the pelvic position may not significantly impact pain improvement.

P133. Measuring the radiographic efficacy of indirect decompression following minimally invasive lumbar interbody fusion: a computed tomography (CT) analysis study

<h3>BACKGROUND CONTEXT</h3> The advancement of MIS techniques has led to increased reliance on indirect decompression techniques. The latest generation of MIS TLIF cages are typically expandable cages that restore disc height and achieve ligamentum flavum unbuckling with associated increased central canal area. While prior studies have measured the extent of indirect decompression associated with ALIF and LLIF, the degree of decompression achieved via MIS-TLIF has not been described. <h3>PURPOSE</h3> Assess the degree of indirect decompression following minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF). <h3>STUDY DESIGN/SETTING</h3> Single-center, multi-surgeon, retrospective review. <h3>PATIENT SAMPLE</h3> Patients undergoing MIS-TLIF without direct decompression between 3/2017 and 3/2021. Patients were included if they had a pre- and postoperative CT scan. <h3>OUTCOME MEASURES</h3> Pre- and postoperative CT scans were used to measure disc height, foraminal area (left and right) and central canal area at the operative level(s). The most recent postoperative patient reported outcome measures (PROMs) between 6 months and 2 years were used to compare against preoperative values. <h3>METHODS</h3> Postoperative CT was performed at 1-43 months based on surgeon-specific protocols. Both pre- and postoperative CT measurements were performed by two observers. PROMs were collected in a prospectively maintained database. Paired tests were used to compare changes in CT measurements and PROMs. Bivariate analysis was also done to assess correlations between the changes in CT measures and PROMs improvement. <h3>RESULTS</h3> A total of 40 patients (48 operative levels) were assessed; 16 (33.3%) of the subjects were female and 24 (50%) were male. The average age was 56.6 ± 15.9 years. The average length of follow-up was 17.9 ± 7.9 months for PROMs and 13.5 ± 9.3 months for postoperative CT imaging. There were 32 (80%) single-level and 8 (20%) two-level cases, with 23 (47.9%) operated at L4L5 and 25 (52.1%) at L5S1. Disc height, foraminal area, and central canal area all increased significantly (p < 0.001). Mean disc height increased 50%, from 4.2 to 6.3mm. Right sided foraminal area increased 23%, from 144 .5 to 177.8mm2, the left increased 21.4% from 142.8 to 173.4mm2, and the central canal increased 16.4% from 228.6 to 266 mm2. All PROMs except for SF12-MCS (p=0.439) showed a statistically significant improvement (p < 0.05). There was no correlation between each change in PROM and the increase in cross sectional canal area. <h3>CONCLUSIONS</h3> MIS-TLIF provides a significant degree of indirect decompression. Disc height, foraminal area and central canal area were all increased following insertion of the interbody cage via the MIS-TLIF technique. PROMs by 2 years demonstrated a statistically significant improvement. <h3>FDA DEVICE/DRUG STATUS</h3> This abstract does not discuss or include any applicable devices or drugs.

Radiographic analysis of neuroforaminal and central canal decompression following lateral lumbar interbody fusion

BackgroundLateral lumbar interbody fusion (LLIF) is a minimally invasive surgical option for treating symptomatic degenerative lumbar spinal stenosis (DLSS) in select patients. However, the efficacy of LLIF for indirectly decompressing the lumbar spine in DLSS, as well as the best radiographic metrics for evaluating such changes, are incompletely understood. MethodsA single-institutional cohort of patients who underwent LLIF for DLSS between 5/2015 – 12/2019 was retrospectively reviewed. Diameter, area, and stenosis grades were measured for the central canal (CC) and neural foramina (NF) at each LLIF level based on preoperative and postoperative T2-weighted MRI. Baseline facet joint (FJ) space, degree of FJ osteoarthritis, presence of spondylolisthesis, interbody graft position, and posterior disc height were analyzed as potential predictors of radiographic outcomes. Changes to all metrics after LLIF were analyzed and compared across lumbar levels. Preoperative and intraoperative predictors of decompression were then assessed using multivariate linear regression. ResultsA total of 102 patients comprising 153 fused levels were analyzed. Pairwise linear regression of stenosis grade to diameter and area revealed significant correlations for both the CC and NF. All metrics except CC area were significantly improved after LLIF (p < 0.05, 2-tailed t-test). Worse FJ osteoarthritis ipsilateral to the surgical approach was predictive of greater post-operative CC and NF stenosis grade (p < 0.05, univariate and multivariate ordinary least squares linear regression). Lumbar levels L3-5 had significantly higher absolute postoperative CC stenosis grades while relative change in CC stenosis at the L2-3 was significantly greater than other lumbar levels (p < 0.05, one-way ANOVA). There were no baseline or postoperative differences in NF stenosis grade across lumbar levels. ConclusionsRadiographically, LLIF is effective at indirect compression of the CC and NF at all lumbar levels, though worse FJ osteoarthritis predicted higher degrees of post-operative stenosis.

Radiographic and clinical evaluation of single-level lateral interbody fusion in patients with severe stenosis analyzed using cluster analysis.

This study was a retrospective review of patients treated in a single institution. We performed a cluster analysis of the degree of preoperative stenosis to investigate the effect of indirect neural decompression in single-level lateral lumbar interbody fusion (LLIF). Surgery is generally indicated for patients with severe stenosis. On the other hand, severe lumbar spinal stenosis is a relative contraindication to LLIF and is excluded in most studies. If LLIF, which is less invasive to treatment, can be applied to severe stenosis patients, it may help treatment. Cluster analysis classified 80 patients into 3 groups based on preoperative central canal area (CCA), preoperative canal diameter (CD), and preoperative Schizas grade: group 1 with severe stenosis (n = 43); group 2 with moderate stenosis (n = 27); and group 3 with mild stenosis (n = 10). Preoperative and immediately postoperative CCA and CD in magnetic resonance imaging were compared between groups. Disc angle (DA) and anterior, posterior, and average disc heights (AvDH) (anterior disc height, posterior disc height, average disc height AvDH) were measured using standing lateral plain radiographs. For clinical analysis, a numeric rating scale was used to evaluate clinical outcomes. DA, anterior disc height, posterior disc height, and AvDH increased significantly after the operation in all groups, but the average changes in these factors did not differ. Mean midsagittal CD and axial CCA on MRI magnetic resonance imaging increased significantly in all groups, but as with DA and DH, the changes in axial CCA and midsagittal CD did not differ between groups. The numeric rating scale score did not differ between groups at any time. The cluster analysis results suggested that postoperative changes in indirect neural decompression for severe stenosis after LLIF similar for moderate and mild stenosis and that pain did not differ according to the severity of stenosis after surgery.

Mechanical Changes of the Lumbar Intervertebral Space and Lordotic Angle Caused by Posterior-to-Anterior Traction Using a Spinal Thermal Massage Device in Healthy People.

Background: The axial (horizontal) traction approach has been traditionally used for treatment of low back pain-related spinal disorders such as nuclear protrusion, primary posterolateral root pain, and lower thoracic disc herniation; however, it is known to have some technical limitations due to reductions of the spinal curve. Lumbar lordosis plays a pivotal function in maintaining sagittal balance. Recently, vertical traction and combination traction have been attracting attention due to improving therapeutic outcomes, although evidence of their clinical application is rare; therefore, this study was conducted to investigate the mechanical changes of lumbar intervertebral space, lordotic angle, and the central spinal canal area through vertical traction treatment using a spinal massage device in healthy participants. Methods: In total, 10 healthy subjects with no musculoskeletal disorders and no physical activity restrictions participated. The participants lay on the experimental device (CGM MB-1901) in supine extended posture and vertical traction force was applied in a posterior-to-anterior direction on the L3–4 and L4–5 lumbar sections at level 1 (baseline) and level 9 (traction mode). Magnetic resonance (MR) images were recorded directly under traction mode using the MRI scanner. The height values of the intervertebral space (anterior, center, and posterior parts) and lordosis angle of the L3–4 and L4–5 sections were measured using Image J software and the central spinal canal area (L4–5) was observed through superimposition method using the MR images. All measurement and image analyses were conducted by 2 experienced radiologists under a single-blinded method. Results: The average height values of the intervertebral space under traction mode were significantly increased in both L3–4 and L4–5 sections compared to baseline, particularly in the anterior and central parts but not in the posterior part. Cobb’s angle also showed significant increases in both L3–4 and L4–5 sections compared to baseline (p < 0.001). The central spinal canal area showed a slightly expanded feature in traction mode. Conclusions: In this pilot experiment, posterior-to-anterior vertical traction on L3–4 and L4–5 sections using a spinal massage device caused positive and significant changes based on increases of the intervertebral space height, lumbar lordosis angle, and central spinal canal area compared to the baseline condition. Our results are expected to be useful as underlying data for the clinical application of vertical traction.

Predictors of indirect neural decompression in minimally invasive transpsoas lateral lumbar interbody fusion.

An advantage of lateral lumbar interbody fusion (LLIF) surgery is the indirect decompression of the neural elements that occurs because of the resulting disc height restoration, spinal realignment, and ligamentotaxis. The degree to which indirect decompression occurs varies; no method exists for effectively predicting which patients will respond. In this study, the authors identify preoperative predictive factors of indirect decompression of the central canal. The authors performed a retrospective evaluation of prospectively collected consecutive patients at a single institution who were treated with LLIF without direct decompression. Preoperative and postoperative MRI was used to grade central canal stenosis, and 3D volumetric reconstructions were used to measure changes in the central canal area (CCA). Multivariate regression was used to identify predictive variables correlated with radiographic increases in the CCA and clinically successful improvement in visual analog scale (VAS) leg pain scores. One hundred seven levels were treated in 73 patients (mean age 68 years). The CCA increased 54% from a mean of 0.96 cm2 to a mean of 1.49 cm2 (p < 0.001). Increases in anterior disc height (74%), posterior disc height (81%), right (25%) and left (22%) foraminal heights, and right (12%) and left (15%) foraminal widths, and reduction of spondylolisthesis (67%) (all p < 0.001) were noted. Multivariate evaluation of predictive variables identified that preoperative spondylolisthesis (p < 0.001), reduced posterior disc height (p = 0.004), and lower body mass index (p = 0.042) were independently associated with radiographic increase in the CCA. Thirty-two patients were treated at a single level and had moderate or severe central stenosis preoperatively. Significant improvements in Oswestry Disability Index and VAS back and leg pain scores were seen in these patients (all p < 0.05). Twenty-five (78%) patients achieved the minimum clinically important difference in VAS leg pain scores, with only 2 (6%) patients requiring direct decompression postoperatively due to persistent symptoms and stenosis. Only increased anterior disc height was predictive of clinical failure to achieve the minimum clinically important difference. LLIF successfully achieves indirect decompression of the CCA, even in patients with substantial central stenosis. Low body mass index, preoperative spondylolisthesis, and disc height collapse appear to be most predictive of successful indirect decompression. Patients with preserved disc height but severe preoperative stenosis are at higher risk of failure to improve clinically.

Morphological changes in the vertebrae and central canal of rat pups born after exposure to the electromagnetic field of pregnant rats

Several studies have investigated the effects of the electromagnetic field (EMF) on the central nervous system. However, we encountered no studies of the effects of EMF applied in the prenatal period on the offspring vertebrae. The aim of this study is to investigate the effect of a 900 megahertz (MHz) EMF applied to rat dams in the prenatal period on the vertebrae of rat pups. Female Sprague Dawley rats weighing 180−250 g were used in the experiment. Rats identified as pregnant were divided into two groups, control (n = 3) and EMF (n = 3). No EMF was applied to the control group pregnant rats. EMF was applied to the EMF group rats for 1 h daily on an equal and standard basis on prenatal days 13−21. All newborn rat pups were divided into pup control (n = 6) (PC) and pup EMF (n = 6) (PEMF) groups, and no treatment was performed on either. All animals were decapitated on day 32, and the spinal cord in the upper thoracic region was harvested. Vertebral tissues were subjected to routine histological procedures. Histopathological examination revealed that PEMF group vertebral cartilage had been converted into bone tissue. Comparison of central canal diameter and area values between the PEMF group and the PC group revealed statistically significant increases in the PEMF group (p = 0.000 and p = 0.001, respectively). Statistical analysıs revealed no significant difference in mean body weights between the two groups (p > 0.530). Based on these findings, we think that 900 MHz EMF applied in the prenatal period affects the development of the vertebrae. This effect causes pathological changes in the rat pup vertebrae. These findings now raise the question of whether EMF also has an impact on neurological and neurosurgical diseases involving the vertebrae.

109. Radiographic predictors of indirect neural decompression in minimally invasive transpsoas lateral interbody fusion

BACKGROUND CONTEXT An advantage of lateral interbody fusion (LLIF) surgery is the resultant indirect decompression of the neural elements that occurs with disc height restoration, restoration of spinal alignment and ligamentotaxis. The degree to which indirect decompression of the spinal canal occurs varies patient to patient, and there remains no method for effectively predicting which patients will or will not respond. PURPOSE In this study, we identify pre- and postoperative predictive factors of radiographic indirect decompression of the central spinal canal. The goal is to help surgeons ascertain which patients best respond to indirect decompression in the setting of lateral interbody fusion. STUDY DESIGN/SETTING This is a retrospective evaluation of a prospectively and consecutively collected cohort of patients treated for degenerative etiologies at a single institution. PATIENT SAMPLE Patients were included if they received a minimally invasive lateral transpsoas interbody fusion by a single surgeon at our institution. Patients were treated for degenerative etiologies. OUTCOME MEASURES A retrospective evaluation of prospectively collected consecutive patients treated with LLIF surgery treated at a single institution without subsequent direct decompression was performed. Pre- and postoperative MRI imaging was used to grade canal stenosis and three-dimensional volumetric reconstructions were used to measure changes in the central canal area (CCA). METHODS Multivariate regression was used to identify predictive variables that correlated with increases in CCA. Independent assessments of canal measurements were made by a blinded board-certified neuroradiologist and a spine surgeon. RESULTS Sixty-six patients with 110 levels were treated with a mean age of 68 years. Forty-six levels (42%) were treated for DDD, 36 levels (33%) for spondylolisthesis, 11 levels (10%) for adjacent segment disease and 17 levels (15%) for deformity. Preoperatively, 19 patients had moderate (29%) and 18 had severe stenosis (27%) with the remainder having mild or no stenosis. Of these 37 patients, only 4 remained severe, 4 were moderate and the rest (78%) improved to mild or no stenosis. CCA increased 41% from a mean of 1.09 to 1.55 cm2 (p 0.05). Multivariate evaluation of predictive variables identified that preoperative anterolisthesis (p=0.002), the presence of vacuum disc phenomenon (p=0.049) and preoperative segmental lordosis (p=0.009) were independently associated with percentage increase in CCA. Age, body mass index, side of approach, pedicle screw fixation, facet grading score, presence of facet effusions, preoperative anterior and posterior disc heights, implant distance from the posterior aspect of the vertebral body and implant height all were not associated (p>0.05). CONCLUSIONS LLIF successfully achieves indirect decompression of the CCA radiographically with a mean change of 41%. Preoperative anterolisthesis on standing films, the presence of vacuum disc phenomenon on computed tomography and preoperative segmental lordosis were independently predictive factors for the percentage increase in CCA that can be achieved. FDA DEVICE/DRUG STATUS This abstract does not discuss or include any applicable devices or drugs.

Radiographic and clinical outcome of lateral lumbar interbody fusion for extreme lumbar spinal stenosis of Schizas grade D: a retrospective study

BackgroundExtreme lumbar spinal stenosis was thought to be a relative contraindication for lateral lumbar interbody fusion (LLIF) and was excluded in most studies. This is a retrospective study to analyze the radiographic and clinical outcome of LLIF for extreme lumbar spinal stenosis of Schizas grade D.MethodsFor radiographic analysis, we included 181 segments from 110 patients who underwent LLIF between June 2017 and December 2018. Lumbar spinal stenosis was graded according to Schizas’ classification. Anterior and posterior disc heights, disc angle, foramen height, spinal canal diameter and central canal area were measured on CT and MRI. For clinical analysis, 18 patients with at least one segment of grade D were included. Visual analogue scale (VAS) and Oswestry disability index (ODI) scores were used to evaluate clinical outcome. Continuous variables were compared using Student’s t-test, with P-values < 0.05 considered to indicate statistically significant differences.ResultsAmong the 181 segments included for radiological evaluation, there were 23 grade A segments, 37 grade B segments, 103 grade C segments and 18 grade D segments. Postoperatively, the average change of midsagittal canal diameter of grade D was significantly greater than that of grade A, and not significantly different compared to grades B and C. As to the average change of disc height, bilateral foraminal height, disc angle and central canal area (CCA), grade D was not significantly different from the others. The average postoperative CCA of grade D was significantly smaller than the average preoperative CCA of grade C. Eighteen patients with grade D stenosis were followed up for an average of 19.61 ± 6.32 months. Clinical evaluation revealed an average improvement in the ODI and VAS scores for back and leg pain by 20.77%, 3.67 and 4.15 points, respectively. Sixteen of 18 segments with grade D underwent posterior decompression.ConclusionThe radiographic decompression effect of LLIF for Schizas grade D segments was comparable with that of other grades. Posterior decompression was necessary for LLIF to achieve a satisfactory clinical outcome for extreme lumbar spinal stenosis of Schizas grade D.

Majority of cerebrospinal fluid-contacting neurons in the spinal cord of C57Bl/6N mice is present in ectopic position unlike in other studied experimental mice strains and mammalian species.

Cerebrospinal fluid contacting neurons (CSF-cNs) represent a specific class of neurons located in close vicinity of brain ventricles and central canal. In contrast with knowledge gained from other vertebrate species, we found that vast majority of CSF-cNs in the spinal cord of C57Bl/6N mice is located in ectopic distal ventral position. However, we found that small number of ectopic CSF-cNs is present also in spinal cord of other investigated experimental mice strains (C57Bl/6J, Balb/C) and mammalian species (Wistar rats, New Zealand White rabbits). Similarly, as the proximal populations, ectopic CSF-cNs retain PKD2L1-immunoreactivity and synaptic contacts with other neurons. On the other side, they show rather multipolar morphology lacking thick dendrite contacting central canal lumen. Ectopic CSF-cNs in the spinal cord of C57Bl/6N mice emerge during whole period devoted to production of CSF-cNs and reach their ventral destinations during first postnatal weeks. In order to identify major gene, whose impairment could trigger translocation of CSF-cNs outside the central canal area, we took advantage of close consanguinity of C57Bl/6J substrain with normal CSF-cN distribution and C57Bl/6N substrain with majority of CSF-cNs in ectopic position. Employing in silico analyses, we ranked polymorphisms in C57Bl/6N substrain and selected genes Crb1, Cyfip2, Adamts12, Plk1, and Herpud2 as the most probable candidates, whose product dysfunction might be responsible for the ectopic distribution of CSF-cNs. Furthermore, segregation analysis of F2 progeny of parental C57Bl/6N and Balb/C mice revealed that polymorphic loci of Crb1 and Cyfip2 underlie the ectopic position of CSF-cNs in the spinal cord of C57Bl/6N mice.

Lateral Lumbar Interbody Fusion: What Is the Evidence of Indirect Neural Decompression? A Systematic Review of the Literature.

In the past decade, lateral lumbar interbody fusion (LLIF) has gained in popularity. A proposed advantage is the achievement of indirect neural decompression. However, evidence of the effectiveness of LLIF in neural decompression in lumbar degenerative conditions remains unclear. We sought to extrapolate clinical and radiological results and consequently the potential benefits and limitations of LLIF in indirect neural decompression in degenerative lumbar diseases. We conducted a systematic review of the literature in English using the 2009 Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines and checklist. Scores on the Oswestry Disability Index (ODI) and visual analog scale (VAS) for back and leg pain were extracted, as were data on the following radiological measurements: disc height (DH), foraminal height (FH), foraminal area (FA), central canal area (CA). In the 42 articles included, data on 2445 patients (3779 levels treated) with a mean follow-up of 14.8 ± 5.9months were analyzed. Mean improvements in VAS back, VAS leg, and ODI scale scores were 4.1 ± 2.5, 3.9 ± 2.2, and 21.9 ± 7.2, respectively. Post-operative DH, FH, FA, and CA measurements increased by 68.6%, 21.9%, 37.7%, and 29.3%, respectively. Clinical results indicate LLIF as an efficient technique in indirect neural decompression. Analysis of radiological data demonstrates the effectiveness of symmetrical foraminal decompression. Data regarding indirect decompression of central canal and lateral recess are inconclusive and contradictory. Bony stenosis appears as an absolute contraindication. The role of facet joint degeneration is unclear. This systematic review provides a reference for surgeons to define the potential and limitations of LLIF in indirect neural elements decompression.

Effects of contusion load on cervical spinal cord: A finite element study.

Injury of cervical spine is a common injury of locomotor system usually accompanied by spinal cord injury, however the injury mechanism of contusion load to the spinal cord is not clear. This study aims to investigate its injury mechanism associated with the contusion load, with different extents of spinal cord compression. A finite element model of cervical spinal cord was established and two scenarios of contusion injury loading conditions, i.e. back-to-front and front-to-back loads, were adopted. Four different compression displacements were applied to the middle section of the cervical spinal cord. The distributions of von Mises stress in middle transverse cross section were obtained from the finite element analysis. For the back-to-front loading scenario, the stress concentration was found in the area at and near the central canal and the damage may lead to the central canal syndrome from biomechanical point of view. With the front-to-back load, the maximum von Mises stress located in central canal area of gray matter when subject to 10% compression, whilst it appeared at the anterior horn when the compression increased. For the white matter, the maximum von Mises stress appeared in the area of the anterior funiculus. This leads to complicated symptoms given rise by damage to multiple locations in the cervical spinal cord. The illustrative results demonstrated the need of considering different loading scenarios in understanding the damage mechanisms of the cervical spinal cord, particularly when the loading conditions were given rise by different pathophysiological causes.

Functional Changes in Patients and Morphological Changes in the Lumbar Intervertebral Disc after Applying Lordotic Curve-Controlled Traction: A Double-Blind Randomized Controlled Study.

Background and Objectives: Lumbar traction is widely used as a non-operative treatment for lumbar intervertebral disc disease. The effect of traditional traction (TT) using linear-type traction devices remains controversial for various reasons, including technical limitations. Thus, the purpose of this study was to compare the effects of the newly developed lumbar lordotic curve-controlled traction (L-LCCT) and TT on functional changes in patients and morphological changes in the vertebral disc. Materials and Methods: A total of 40 patients with lumbar intervertebral disc disease at the L4/5 or L5/S1 level as confirmed by magnetic resonance imaging were recruited and divided into two groups (L-LCCT or TT). The comprehensive health status changes of the patients were recorded using pain and functional scores (the visual analogue scale, the Oswestry Disability Index, and the Roland–Morris Disability Questionnaire) and morphological changes (in the lumbar central canal area) before and after traction treatment. Results: Pain scores were significantly decreased after traction in both groups (p < 0.05). However, functional scores and morphological changes improved significantly after treatment in the L-LCCT group only (p < 0.05). Conclusions: We suggest that L-LCCT is a viable option for resolving the technical limitations of TT by maintaining the lumbar lordotic curve in patients with lumbar intervertebral disc disease.

Comparing Radiographic Parameters for Single-Level L5-S1 Interbody Fusion: Anterior Lumbar (ALIF) Versus Transforaminal Lumbar Interbody Fusion (TLIF)

Abstract INTRODUCTION The lumbosacral junction acts as a transition point between the mobile lumbar spine and the rigid pelvis. It is thereby susceptible to degenerative changes necessitating fusion at L5-S1. In this study, we compared radiographic outcomes observed from single-level anterior lumbar interbody fusion (ALIF) and transforaminal lumbar interbody fusion (TLIF) at this level. METHODS Retrospective review of single-level ALIF and TLIF with up to one level PSF at L5-S1 between May 2007 and October 2018 was undertaken. X-ray measurements were gathered for lumbar lordosis, segmental lordosis, pelvic tilt, sacral slope, pelvic incidence, pelvic incidence-lumbar lordosis mismatch, anterior/posterior disc height, and sagittal vertical axis. Computed tomography /magnetic resonance imaging was used to determine central canal area, sagittal diameter, foraminal height, and foraminal area. RESULTS A total of 47 ALIF patients and 50 TLIF patients were included. Patients averaged 53.7 ± 10.1 yr of age for ALIF and 49.4 ± 14.7 yr old for TLIF (P = .094) with significant differences (P = .0017) seen with gender as ALIF had 60.4% males and TLIF 70.0% females. Single-level ALIF led to significantly (P = .0010) more segmental lordosis (+5.75° ± 7.31°) than TLIF (+0.25° ± 6.55°), though differences in lumbar lordosis were not statistically significant (P = .52). ALIF significantly increased both anterior (+10.4 ± 4.32 mm vs +4.30 ± 3.55 mm; P &lt; .0001) and posterior disc height (+4.33 ± 3.32 mm vs + 2.98 ± 2.07 mm; P = .043) than TLIF. Changes in sagittal vertical axis also significantly differed (P = .030) with ALIF decreasing sagittal vertical axis by 17.8 ± 26.4 mm from +60.3 mm to + 42.5 mm, and TLIF increasing by 0.95 ± 25.8 mm from 39.9 mm to 40.9 mm. Pelvic tilt, sacral slope, pelvic incidence, pelvic incidence-lumbar lordosis mismatch had no significant differences. No statistically significant differences were observed with central canal area, sagittal diameter, foraminal height or foraminal area between ALIF and TLIF. CONCLUSION At L5-S1, the ALIF approach leads to increased segmental lordosis, disc height, while also decreasing sagittal vertical axis to a significant degree than TLIF. However, these two approaches were no different with regards to pelvic parameters and measures of central canal and foraminal decompression.

Bony Lateral Recess Stenosis and Other Radiographic Predictors of Failed Indirect Decompression via Extreme Lateral Interbody Fusion: Multi-Institutional Analysis of 101 Consecutive Spinal Levels.

Although extreme lateral interbody fusion (XLIF) largely provides successful indirect decompression, some patients have recurrent same-level pain and functional disability. Identifying risk factors for this failure would facilitate better patient selection and improve outcomes. The aim of this study is to identify preoperative radiographic risk factors for failure of XLIF. Patients undergoing XLIF were prospectively enrolled by 3 surgeons at 3 separate institutions. Radiographic variables measured included (1) anterior and posterior disc height, (2) foramen height and area, (3) central canal diameter, (4) central canal area, (5) right and left subarticular diameters, (6) facet arthropathy grade, and (7) presence of bony lateral recess stenosis. Patients failed indirect decompression if Oswestry Disability Index (ODI) scores did not improve by 20 points or revision surgery was required within 6 months postoperatively. Univariate and multivariate analyses were performed to identify radiographic predictors of failure of indirect decompression. Of the 45 patients (age 65.6 ± 10.5 years; 14 male) involving 101 spinal levels included in this study, 13 (29%) failed indirect decompression. From univariate analysis, these patients had significantly smaller central canal diameter, foraminal height, and disc height (P < 0.05). In multivariate analysis of these parameters and those trending toward significance, bony lateral recess stenosis was the only significant independent predictor for failure of indirect decompression (coefficient, 0.55 [0.24-0.85]; P < 0.001). Bony lateral recess stenosis is an independent predictor for failure to achieve adequate spinal decompression via XLIF and thus may benefit from undergoing direct decompression.

Potential and Limitations of Neural Decompression in Extreme Lateral Interbody Fusion-A Systematic Review.

Extreme lateral interbody fusion (ELIF) is a powerful tool for interbody fusion and coronal deformity correction. However, evidence regarding the success of ELIF in decompressing foraminal, lateral recess, and central canal stenosis is lacking. We performed a systematic review of current literature on the potential and limitations of ELIF to indirectly decompress neural elements. A literature search using PubMed, Cochrane, and ScienceDirect databases was performed according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses criteria. Information on study design, sample size, population, procedure, number and location of involved levels, follow-up time, and complications as well as information on conflict of interest was extracted and evaluated. We selected 20 publications including 1080 patients for review. Most publications (90%) were retrospective case series. Most frequent indications for ELIF included degenerative disc disease, spinal stenosis, spondylolisthesis, and degenerative scoliosis. Most studies revealed significant improvement in radiographic and clinical outcome after ELIF. Mean foraminal area, central canal area, and subarticular diameter increased by 31.6 mm2, 28.5mm2, and 0.85 mm. ELIF successfully improved foraminal stenosis. Contradictory results were found for indirect decompression of central canal stenosis. Data on lateral recess stenosis were scarce. Current data suggest ELIF to be an efficient technique in decompression of foraminal stenosis. Evidence on decompression of central canal or lateral recess stenosis via ELIF is low, and results are inconsistent. Most studies are limited by study design, sample size, and potential conflicts of interest.

Are Locked Facets a Contraindication for Extreme Lateral Interbody Fusion?

Extreme lateral interbody fusion (ELIF) has gained popularity as a minimally invasive treatment allowing for indirect decompression of neural elements. However, evidence regarding the influence of facet degeneration (FD) and facet tropism (FT) toward indirect decompression is lacking. The aim of the study was to evaluate whether indirect decompression is impaired by FD and FT in patients undergoing ELIF. Thirty-seven patients undergoing ELIF were included in a retrospective study. Radiographic parameters including disk height, segmental disk angle, foraminal area, FD, FT, and clinical outcome parameters (Oswestry Disability Index and Visual Analog Scale) were measured preoperatively and postoperatively. FD and FT were correlated with radiographic and clinical outcome parameters in order to determine predictors restricting indirect decompression. Thirty-seven patients with a total of 74 levels were analyzed. Clinical and radiographic outcome measures including central canal area (Δ=+17.2 mm2), mean disk height (Δ=+3 mm), and foraminal area (Δ=+9.9 mm2) revealed significant improvement compared with before surgery (P ≤ 0.05). Patients with severe FD (grade 4) were more likely to have FT ≥ 12 degrees (32.3%) than patients without/mild (grades 0 and 1; 10%) or moderate FD (grades 2 and 3; 13%), P ≤ 0.05. FD and FT did not affect disk height restoration, foraminal area, canal surface area, or clinical outcome measures (P ≥ 0.05). Indirect decompression of neural elements in ELIF is not impaired by FD and FT are not relative contraindications in patients undergoing ELIF.