Cross-sectional Area Of Spinal Canal Research Articles

Developmental cervical spinal canal size: population reference range.

The developmental size of the cervical spinal canal varies considerably. Neural compression and injury are more likely with a developmentally small spinal canal. This study was designed to develop a population reference range for developmental cervical spinal canal size for the Hong Kong population. Prospective study of 522 ambulatory patients (256 males, 266 females, mean age 55±18 years; range, 20-89 years) who underwent computed tomography (CT) neck examinations. Using a manually operated segmentation program, spinal canal, and vertebral body cross-sectional area (CSA), anteroposterior (AP) sagittal diameter, and width were measured at each level from C3-C7. Patient height and weight were measured. Considerable variation in spinal canal size existed with, for example, a 164-168% variation exists for males and females between the largest and smallest spinal canal CSA at C5. All spinal canal measurements increased slightly with height (r=0.25-0.36, P<0.001), while vertebral body AP sagittal diameter increased with age (r=0.48-0.51, P<0.001). All spinal canal measurements were larger (<0.0001) in males. Although spinal canal CSA was larger in males (at C5, males 276.0±41.5 mm2; females 252.6±38.4 mm2), relative to vertebral body CSA, spinal canal CSA was larger in females. Arbitrary population thresholds indicating the smallest 25% spinal canal CSA and AP sagittal diameter as well as other parameters were defined. There is a large variation in developmental cervical spinal canal size within the Hong Kong population. A reference range of developmental spinal canal size was developed which will enable an objective assessment of an individual's cervical spinal canal size relative to the wider population.

Percutaneous Endoscopic Suprapedicular Decompression in the Treatment of Down-Migrated Lumbar DiscHerniation

[OBJECTIVE]: This study aimed to investigate the clinical efficacy of percutaneous endoscopic suprapedicular decompression in treatment of down-migrated lumbar disc herniation. [METHODS]: The clinical data of 43 patients with down-migrated lumbar disc herniation treated with endoscopic surgery at our hospital between January 2022 and January 2023 were retrospectively analysed. Twenty-two and 21 patients underwent percutaneous endoscopic decompression using the suprapedicular and TESSYS approaches, respectively. The perioperative, follow-up, and imaging data of the groups were compared. [RESULTS]: Surgery was uneventful in both groups. The number of intraoperative fluoroscopies and duration of surgery were significantly lower in the suprapedicular group (p<0.05). The patients in both groups were followed up for at least 12 months. At the last follow-up, lumbar pain and leg pain visual analogue scale (VAS), Oswestry Disability Index (ODI), and 36-Item Short Form Health Survey (SF-36) scores were significantly improved in both groups compared with preoperative values (p<0.05); the differences in these indexes between the two groups were not significant preoperatively (p>0.05). However, at the last postoperative follow-up, lumbar pain VAS scores were significantly better in the suprapedicular group (0.83±0.85 vs. 2.54±1.32, p<0.05). There was no significant change in intervertebral space height or lumbar lordotic angle compared with preoperative values in either group at the last follow-up (p>0.05). However, the spinal canal cross-sectional area significantly increased (p<0.05). [CONCLUSION]: The treatment of down-migrated lumbar disc herniation via a suprapedicular approach enabled the incision of the superior margin of the pedicle as needed under direct vision, involved less fluoroscopy while preserving facet joint stability, and enabled targeted removal of the herniated nucleus pulposus, thus greatly reducing residual nucleus pulposus. This surgical procedure was safe, rapid, and showed satisfactory therapeutic efficacy.

Surgical versus nonsurgical management of lumbar degenerative spondylolisthesis based on spinal canal cross-sectional area.

Disability and pain associated with lumbar degenerative spondylolisthesis (LDS) result in a significant burden on both the healthcare costs and patients' quality of life. Currently, there exists controversy regarding employment of either nonsurgical management (NSM) or surgical management (SM) in a clinical setting. Spinal canal cross-sectional area (SCA) has been an important morphological parameter for the analysis of LDS. However, there is lack of research about the comparative value of NSM and SM according to SCA. Moreover, previous research have not yet evaluated the clinical most suitable cutoff values of SCA. The objective of this research was to evaluate the effective of NSM and SM for LDS using SCA as an objective morphological parameter. The axial T2 magnetic resonance imaging images were obtained from each patient. We collected SCA samples from 149 patients with LDS. 72 patients underwent SM and the rest did NSM. We measured SCA at the L4/5 LDS on magnetic resonance imaging using a picture archiving and communications system. We measured SCA at the intervertebral disk posterior border, turning down to reach the facet joint side on the opposite edge at the L4/5 level. The average SCA value was 114.34 ± 48.11 mm2 in the NSM group and 69.88 ± 27.87 mm2 in the SM group. Therefore, the SM group had considerably lower SCA (P < .001). In view of the effectiveness of SCA as a prediction factor of surgical option, Receiver Operating Characteristic curve analysis show the optimal cutoff value for SCA as 83.21 mm2, with 70.8% sensitivity, 71.4% specificity, and an area under the curve of 0.80 (95% CI, 0.73-0.87). The narrower the SCA, the higher the probability of SM. Thus, it is proposed that to evaluate surgical decision making, the pain physician should carefully inspect the SCA.

Comparison of the Tubular Approach and Uniportal Interlaminar Full-Endoscopic Approach in the Treatment of Lumbar Spinal Stenosis: Our 3-Year Results

To report the long-term results of patients with lumbar spinal stenosis (LSS), for whom we applied the tubular and endoscopic approaches and previously published the short-term results MATERIAL AND METHOD: A multicenter, prospective, randomized, double-blind study was carried out to evaluate two groups of patients with LSS who underwent microsurgery via a tubular retractor with a unilateral approach (T-group) and bilateral spinal decompression using uniportal interlaminar endoscopic approaches (E-group). Dural sac cross-sectional and spinal canal cross-sectional areas were measured with the patients' preoperative and postoperative magnetic resonance images. The Visual Analog Scale (VAS), Oswestry Disability Index (ODI), and Japanese Orthopedic Association (JOA) scores in the preoperative period and the 1st, 2nd, and 3rd years after surgery were evaluated. Twenty patients met the inclusion criteria for the research (T group; n:10, E group; n:10). The groups' VAS (respectively; P=.315, P=.529, and P=.853), ODI (respectively; P=.529, P=.739, and P=.912), and JOA (respectively; P=.436, P =.853, and P=.684) scores from the 1st, 2nd, and 3rd postoperative years were quite good compared to the preoperative period, but there was no statistically significant difference. A significant difference was found in E-Group, with less blood loss (P < .001). The long-term results of the patients with LSS treated with tubular and endoscopic approaches were similar and very good. Bilateral decompression with minimally invasive spinal surgery methods can be completed with less tissue damage, complications, and blood loss with the unilateral approach.

Increased vertebral body area, disc and facet joint degeneration throughout the lumbar spine in patients with lumbosacral transitional vertebrae.

Lumbosacral transitional vertebrae (LSTV), developmental spinal canal stenosis, lumbar disc and facet joint degeneration are all common lumbar spine conditions. This study explores the relationship between these entities. Five hundred and five patients (254 females, 251 males), mean age 57 ± 13 years, who underwent abdominopelvic CT examinations were studied. Vertebral body cross-sectional area (CSA), spinal canal CSA, width and depth were measured from L1 to L5. The presence of LSTV was documented and the severity of disc/facet joint degeneration graded. LSTV was present in 155 (31%) of 505 patients, being twice as common in males than in females. After controlling for age, height and weight, vertebral body CSAs from L1 to L5 in male LSTV patients were, on average, 9.8% larger than those in male non-LSTV patients (p < 0.0001 for all) while vertebral body areas at L3 and L4 were 4.5% larger in female LSTV patients than in non-LSTV female patients. Disc degeneration from L2/3 to L5/S1 and facet joint degeneration from L2/3 to L4/5 were more severe in LSTV patients. LSTV Castellvi Type II patients appear to be most prone to disc and facet degeneration. LSTV patients, and particularly male patients, have an increased vertebral body CSA compared to non-LSTV patients throughout the lumbar spine. LSTV patients also have more severe disc and facet joint degeneration. The increase in vertebral body area may be contributing to the increased lumbar and facet joint degeneration seen in LSTV patients. • LSTV patients have increased vertebral body cross-sectional area throughout their lumbar spine compared to non-LSTV patients. This vertebral body area increase was more pronounced in male patients and also apparent in younger patients with LSTV. • LSTV patients have increased disc and facet joint degeneration affecting most of the lumbar spine than non-LSTV patients. • Increased vertebral body area may contribute to the increased lumbar disc and facet joint degeneration seen in LSTV patients.

Usefulness of Lateral Lumbar Interbody Fusion Combined with Indirect Decompression for Degenerative Lumbar Spondylolisthesis: A Systematic Review.

Background and Objective: The aim of this review was to analyze the existing literature and investigate the outcomes or complications of lateral lumbar interbody fusion (LLIF) combined with indirect decompression for degenerative lumbar spondylolisthesis (DS). Materials and Methods: A database search algorithm was used to query MEDLINE, COCHRANE, and EMBASE to identify the literature reporting LLIF with indirect decompression for DS between January 2010 and December 2021. Improvements in outcome measures and complication rates were pooled and tested for significance. Results: A total of 412 publications were assessed, and 12 studies satisfied the inclusion criteria after full review. The pooled data available in the included studies showed that 438 patients with lumbar spondylolisthesis (mean age 65.2 years; mean body mass index (BMI) 38.1 kg/m2) underwent LLIF. A total of 546 disc spaces were operated on. The most frequently treated levels were L4–L5 and L3–L4. Clinically, the average improvement was 32.5% in ODI, 46.3 mm in low back pain, and 48.3 mm in leg pain estimated from the studies included. SF-36 PCS improved by 51.5% and MCS improved by 19.5%. For radiological outcomes, a reduction in slippage was seen in 6.3%. Disc height increased by 55%, foraminal height increased by 21.1%, the foraminal area on the approach side increased by 21.9%, and on the opposite side it increased by 26.1%. The cross-sectional spinal canal area increased by 20.6% after surgery. Post-operative complications occurred in 5–40% of patients with thigh symptoms, such as anterior thigh numbness, dysesthesia, discomfort, pain, and sensory deficits. Conclusions: Indirect decompression by LLIF for DS is an effective method for improving pain and dysfunction with less surgical invasion. In addition, it has the effect of significantly improving disc height, foraminal height and area, and segmental lordosis on radiological outcomes compared to the posterior approach.

Dissatisfaction Risk Factors of Patients after Laminectomy for Thoracic Ossification of Ligamentum Flavum: A Retrospective Cohort Study of Different Follow-Up Periods.

Objectives To explore the influencing factors of satisfaction with postoperative treatment in patients diagnosed with thoracic ossification of the ligamentum flavum during different follow-up periods. Methods This was a retrospective study of 57 patients who were diagnosed with thoracic ossification of ligamentum flavum (TOLF) and treated with laminectomy in the Spine Surgery Department of the Third Hospital of Hebei Medical University from January 2010 to January 2017. The Patient Satisfaction Index (PSI) was collected at discharge and at 6-month, 1-year, and the last follow-up. According to the evaluation results, the patients could be divided into a satisfied group and a dissatisfied group. The patient's Japanese Orthopaedic Association (JOA) score improvement rate was evaluated at the last follow-up. Possible influencing factors of the two groups of patients were compared and the related influencing factors of satisfaction with postoperative treatment in patients during different follow-up periods were summarized. Results At the time of discharge, the dissatisfied and satisfied groups had significant differences in variables of diabetes mellitus, duration of preoperative symptoms, urination disorder, intramedullary signal change on MRI, dural ossification, residual rate of cross-sectional spinal canal area on CT, shape on the sagittal MRI, hospital stay, hospitalization expenses, postoperative pain in LE VAS, delayed wound healing, postoperative depression, and intercostal pain (P < 0.05). There were also significant differences in urination disorder, postoperative pain according to the LE VAS, JOA score, and postoperative depression during the 6-month follow-up (P < 0.05). There were no significant differences in other variables between the two groups (P > 0.05). One year after the operation, there were significant differences between the dissatisfied group and the satisfied group in urination disorder, JOA score, and symptom recurrence (P < 0.05). There were also significant differences in the JOA score and symptom recurrence at the final follow-up (P < 0.05). For further analysis, the duration of preoperative symptoms in the satisfied group was less than 24 months and the duration of preoperative symptoms in the dissatisfied group was more than 24 months. The JOA scores of patients in the satisfied group and the dissatisfied group increased gradually with the improvement of neurological function in different follow-up periods, but, at the last follow-up, the JOA scores of patients in the satisfied group were significantly higher than those in the dissatisfied group. Conclusions In conclusion, for thoracic ossification of ligamentum flavum patients who received laminectomy, dissatisfaction with the early and medium-term postoperative results may be related to diabetes, the duration of preoperative symptoms, hospitalization expenses, delayed wound healing, intercostal pain, and urination disorder, and dissatisfaction with the long-term postoperative results might be related to the low JOA score improvement rate and symptom recurrence.

Do Obliquity and Position of the Oblique Lumbar Interbody Fusion Cage Influence the Degree of Indirect Decompression of Foraminal Stenosis?

ObjectiveOblique lumbar interbody fusion (OLIF) is a surgical technique that utilizes a large interbody cage to indirectly decompress neural elements. The position of the cage relative to the vertebral body could affect the degree of foraminal decompression. Previous studies determined the position of the cage using plain radiographs, with conflicting results regarding the influence of the position of the cage to the degree of neural foramen decompression. Because of the cage obliquity, computed tomography (CT) has better accuracy than plain radiograph for the measurement of the obliquely inserted cage. The objective of this study is to find the correlation between the position of the OLIF cage with the degree of indirect decompression of foraminal stenosis using CT and magnetic resonance imaging (MRI). MethodsWe review imaging of 46 patients who underwent OLIF from L2-L5 for 68 levels. Segmental lordosis (SL) was measured in a plain radiograph. The positions of the cage were measured in CT. Spinal canal cross-sectional area (SCSA), and foraminal crosssectional area (FSCA) measurements using MRI were taken into consideration. ResultsPatients’ mean age was 69.7 years. SL increases 3.0±5.1 degrees. Significant increases in SCSA (33.3%), FCSA (43.7% on the left and 45.0% on the right foramen) were found (p<0.001). Multiple linear regression analysis shows putting the cage in the more posterior position correlated with more increase of FSCA and decreases SL correction. The position of the cage does not affect the degree of the central spinal canal decompression. Obliquity of the cage does not result in different degrees of foraminal decompression between right and left side neural foramen. ConclusionCage position near the posterior part of the vertebral body increases the decompression effect of the neural foramen while putting the cage in the more anterior position correlated with increases SL.

Correlation Analysis for Selection of Microtitanium Plates with Different Specifications for Use in a Cervical Vertebral Dome Expansion Laminoplasty.

ObjectiveTo analyze correlations between the selection of microtitanium plates with different specifications for use in a cervical vertebral dome expansion laminoplasty.MethodsSixteen patients that underwent the cervical vertebral dome expansion laminoplasty with a cervical spinal stenosis angioplasty procedure for treatment of their cervical spinal cords were recruited at our hospital. From February 2017 to September 2018, medical records confirmed that all patients underwent cervical CT and MRI tests pre‐ and postsurgery. The anteroposterior diameter of the spinal canal, changes in the cross‐sectional area of the spinal canal, and the pre‐ and postsurgery distance of the cervical spinal cord after applying microtitanium plates with different lengths were measured by Mimics version 17.0 software (Materialise NV, Leuven, Belgium). A statistical regression and correlation analysis of relevant specification parameters of the microtitanium plate was then studied.ResultsAs the size of the microtitanium plate increased, we found that the cross‐sectional area of cervical spinal canal and distance between the descendants of the lamina and the distance of cervical spinal cord concordantly increased, and these data changes linearly. The regression equation associated with sagittal diameter, cross‐sectional area, and posterior movement distance of the cervical spinal cord was obtained.ConclusionAccording to the correlation analysis of imaging data changes, the regression equation was obtained to guide the selection of microtitanium plates with appropriate specifications in a cervical vertebral dome expansion laminoplasty.

Clinical effect analysis of laminectomy alone and laminectomy with instrumentation in the treatment of TOLF

BackgroundTo explore the clinical effect of laminectomy alone and laminectomy with instrumentation in the treatment of TOLF.MethodsA retrospective study was conducted on the clinical data of 142 patients with TOLF and laminectomy who underwent spine surgery at XXX Medical University from January 2003 to January 2018. According to whether the laminectomy was combined with instrumentation, the patients were divided into two groups: group A (laminectomy alone (LA), n = 77) and group B (laminectomy with instrumentation (LI), n = 65). Comparisons of possible influencing factors of demographic variables and operation-related variables were carried out between the two groups. In this study, the clinical effects of LA and LI in the treatment of TOLF were discussed. Thus, we explored the clinical effect of LA and LI in the treatment of TOLF.ResultsIn terms of demographics, there was a statistically significant difference in BMI between group A and group B (P < 0.05). The differences in age, sex, smoking, drinking, heart disease, hypertension and diabetes were not statistically significant (P > 0.05). In terms of preoperative symptoms, there was a significant difference in gait disturbance, pain in the LE, and urination disorder between group A and group B (P < 0.05), but there was no significant difference in other variables between the two groups (P > 0.05). In terms of operation-related variables, there was a significant difference in the preoperative duration of symptoms, intramedullary signal change on MRI, dural ossification, residual rate of cross-sectional spinal canal area on CT, shape on the sagittal MRI, operation time, pre-mJOA, post-mJOA at 1 year, and leakage of cerebrospinal fluid between group A and group B (P < 0.05), but there was no significant difference in other variables between the two groups (P > 0.05). The preoperative average JOA score of group A was 6.37 and that of group B was 5.19. In group A, the average JOA score at 6 months, 1 year and 2 years after surgery was 7.87, 8.23 and 8.26, respectively, and the average JOA score improvement rate was 32.79 %, 38.32 and 38.53 %, respectively. In group B, the average JOA score at 6 months, 1 year and 2 years after surgery was 7.74, 8.15 and 8.29, respectively, and the average JOA score improvement rate was 39.15 %, 46.86 and 47.12 %, respectively.ConclusionsCurrently, there is no consensus on whether instrumentation is needed after laminectomy for TOLF. We found that for patients with a long duration of gait disturbance, urination disorder, preoperative duration of symptoms, intramedullary signal change on MRI, dural ossification, residual rate of cross-sectional spinal canal area on CT less than 60 %, and shape on the sagittal MRI being beak and low, pre-mJOA had better clinical effects after LI as compared to those after LA, and the incidence of perioperative complications was lower.

Magnetic resonance imaging changes in multifidus and psoas muscles in patients with lumbar spinal stenosis

Objectives: The aim of this study is to evaluate the relationship between the spinal canal cross-sectional area (SCCSA) at the stenosis level, the cross-sectional areas of the multifidus (MF) muscle at the L3-S1 levels, and the cross-sectional areas of the psoas muscle (PSCSA) at the L3 level in patients with nerve compression due to lumbar spinal stenosis. Methods: A total of 280 patients were included in the study, 140 in the control group and 140 with lumbar spinal stenosis that had been detected with magnetic resonance imaging (MRI). The patients' ages, gender, SCCSA at the level of stenosis, PSCSA at L3 level, MFCSA at L3-S1 levels, and degrees of atrophy caused by multifidus muscle fatty degeneration were evaluated and compared with the control group whether the comparison was statistically significant or not. Results: PSCSA values at the L3 level and MFCSA at the L3-4 level (r=0.555, p &amp;lt; 0.01), MFCSA at the L4-L5 level (r=0.559, p &amp;lt; 0.01), and MFCSA at the L5-S1 level (r=0.429, p &amp;lt; 0.01) were found to have a statistically significant positive correlation. In addition, MFCSA at the L3-4 level (p &amp;lt; 0.001), MFCSA at the L4-5 level (p &amp;lt; 0.001), MFCSA at the L5-S1 level (p &amp;lt; 0.001),the L3-L4 SCCSA (p &amp;lt; 0.001), and the L4-L5 SCCSA (p &amp;lt; 0.001) mean values were found to be statistically significantly lower than the mean of the cases in the control group. Conclusions: Compared to the control group, a significant correlation was found with a decrease in the CSA of the multifidus muscle and the presence of fatty degeneration of the multifidus muscle in patients with spinal stenosis. However, in the CSA of the psoas muscle at the L3 level, it was found that there was no correlation between patients with spinal stenosis and the control group.

Cluster analysis to predict factors associated with sufficient indirect decompression immediately after single-level lateral lumbar interbody fusion

ObjectiveChanges in indirect decompression using lateral lumbar interbody fusion (LLIF) were classified into three clusters based on cluster analysis. We investigated cage variables and position to assess the effects of single-level LLIF on indirect decompression. MethodsCluster analysis was used to classify patients into three groups based on the change in the axial cross-sectional spinal canal area (ΔCSA): group 1 with slight postoperative indirect decompression (n = 35); group 2 with average indirect decompression (n = 19); and group 3 with marked indirect decompression (n = 13). Preoperative and immediately postoperative imaging data were compared between groups. ResultsPostoperative segmental lordosis, anterior, posterior, and average disc height increased significantly in each group, but the differences between groups were not significant. Cage length (p = 0.251) and cage height (p = 0.709) did not differ, but cage position differed significantly between groups (p < 0.05). ΔCSA correlated significantly with cage position for all 67 levels (r = 0.411, p < 0.01), but this association was not significant in group 2 (r = − 0.367, p = 0.122) or group 3 (r = − 0.005, p = 0.986). ΔCSA correlated with cage height in group 2 (r = 0.645, p < 0.01) and with cage width in group 3 (r = 0.644, p < 0.05). ConclusionsThe cluster analysis results suggest that placing the cage in the posterior position might be effective for expanding the CSA, but other factors, such as cage height or width, may also influence the sufficiency of LLIF.

The correlation of intraoperative distraction of intervertebral disc with the postoperative canal and foramen expansion following oblique lumbar interbody fusion.

To examine the correlation of intraoperative distraction of intervertebral disc with the postoperative central canal and foramen expansion by oblique lumbar interbody fusion (OLIF) with indirect decompression. Patients who underwent OLIF between October 2013 and April 2017 were included. Clinical outcomes included back and leg pain evaluated by visual analog scale (VAS) and Oswestry Disability Index (ODI). Intraoperative radiographic parameters of height ratio [(HR) = disc height/intervertebral body height)] and cage location were evaluated on intraoperative fluoroscopic images. Disc height (DH), foraminal height (FH), cross-sectional area of spinal canal (CSAC), and CSA of the foramen (CSAF) were measured. A total of 47 patients involving 62 levels were enrolled in this study. Mean follow-up was 43.8 ± 12.0months. These patients reported an improvement of 61.7% in VAS back, 68.1% in VAS leg, and 46% in ODI (all p < 0.01). Radiographic parameters including HR, DH, FH, CSAC, and CSAF were also significantly increased by 32.6%, 48.2%, 21.4%, 44.0%, and 40.1% (left-side CSAF) or 45.4% (right-side CSAF), respectively (p < 0.05). HR increment was correlated with CSA (canal and foramen) increment. Slightly higher improvements of HR, DH, FH, CSAC, and CSAF (both sides) were noted when cage was located at middle rather than anterior (p > 0.05). The ligamentotaxis effect of OLIF is capable of supporting indirect decompression of central canal and neural foramina and clinical improvement. HR is a reliable intraoperative assessment method. In addition, intraoperative HR increment was correlated with postoperative neural elements expansion.

Decreasing thickness and remodeling of ligamentum flavum after oblique lumbar interbody fusion.

Ligamentum flavum is one of the structures that could compress the spinal canal. Few studies have reported atrophy of ligamentum flavum after spinal fusion. The purpose of this study was to demonstrate the reduction of ligamentum flavum size after oblique lumbar interbody fusion (OLIF) using magnetic resonance imaging (MRI). Seventeen patients who underwent OLIF without direct decompression were included. The MRI was obtained at the preoperative period, immediate postoperative period, and the follow-up period. Disc height (DH) was measured in plain radiograph. MRI measurements were spinal canal cross-sectional area (SCSA), ligamentum flavum thickness (LFT), ligamentum flavum area (LFA), and foraminal area (FA). Mean age of the patients was 68.5 ± 10.8. Mean times between postoperative MRI and follow-up MRI were 20.2 ± 11.9months. Mean disc height increased from 7.6 ± 1.6 to 11.6 ± 1.7mm at an immediate postoperative period but decreased to 10.1 ± 1.6mm during follow-up (p < 0.001). SCSA increased from 96.9 ± 54.9 to 136.0 ± 72.7mm2 and 171.4 ± 76.10mm2 during follow-up (p < 0.001). LFT decreased from 3.9 ± 1.2 to 3.2 ± 0.8mm (17.9%) and further decreased to 2.9 ± 0.7mm during follow-up (9.4%) (p < 0.001). LFA decreased from 97.4 ± 36.9 to 86.1 ± 36.9mm2 (11.6%) and further decreased to 77.2 ± 32.5mm2 during follow-up (10.3%) (p = 0.001). FA increased from 69.2 ± 26.6 to 96.1 ± 23.0mm2 and increased to 112.9 ± 23.0mm2 during follow-up (p < 0.001). OLIF could decompress the spinal canal and foraminal canal indirectly. Despite the diminishing disc height during the follow-up period, the spinal canal was further increased in size from the remodeling of the ligamentum flavum.

Early effectiveness of oblique lateral interbody fusion combined with pedicle screw fixation via small incision Wiltse approach for lumbar spondylolisthesis

To investigate the early effctiveness of oblique lateral interbody fusion (OLIF) combined with pedicle screw fixation via small incision Wiltse approach for the treatment of lumbar spondylolisthesis. Between January 2016 and December 2016, 21 patients with lumbar spondylolisthesis were treated with OLIF and pedicle screw fixation via small incision Wiltse approach. There were 9 males and 12 females, aged 57-73 years, with an average age of 64.5 years. The disease duration was 24-60 months, with an average of 34.6 months. All cases were spondylolisthesis at L 4 (15 cases of degreeⅠ, 6 cases of degreeⅡ); 1 case had vertebral arch isthmus, and 20 cases had spinal stenosis. Japanese Orthopaedic Association (JOA) scoring system was used to evaluate the effectiveness before operation and at last follow-up. Before operation and at 2 days after operation, anteroposterior and lateral X-ray films and CT were taken to measure the sagittal diameter and cross-sectional area of the spinal canal, and calculate the intervertebral height and degree of spondylolisthesis. At 6 months after operation, the intervertebral fusion was evaluated by CT. The operation time was 120-180 minutes, with an average of 155 minutes; the intraoperative blood loss was 100-340 mL, with an average of 225.5 mL. One patient had slight injury of lower endplate, 1 patient had numbness of thigh and weakness of hip flexion after operation, 1 patient had sympathetic nerve trunk injury. All the cases were followed up 12-18 months, with an average of 14.3 months. The symptoms of low back pain, leg pain, and numbness of lower limbs significantly relieved after operation, and there was no complication such as protrusion of fusion cage, screw breakage, and endplate collapse. At 2 days after operation, the intervertebral height, degree of spondylolisthesis, sagittal diameter of spinal canal, and cross-sectional area of spinal canal significantly improved compared with preoperative ones ( P<0.05). At 6 months after operation, CT showed that 1 patient had poor interbody fusion (grade Ⅲ), the other 20 patients had good interbody fusion (grade Ⅰ and Ⅱ), and the interbody fusion rate was 95.2%. At last follow-up, JOA score of lumbar spine significantly increased compared with that before operation ( t=24.980, P=0.000). OLIF combined with pedicle screw fixation via small incision Wiltse approach for the lumbar spondylolisthesis has minimally invasive features, such as less trauma, fewer complications, and higher intervertebral fusion rate. It is a safe and effective method.

The influence of knee bolster on lumbar spinal stenosis parameters on MR images.

To estimate the effect of the knee bolster use during an MRI on lumbar spinal stenosis parameters and low back pain-related disability. A repeated-measurement study of 27 males and 19 females with mean age 55.78 ± 14.36, referred for an MRI of the lumbar spine due to low back pain, performed with and without standard knee bolster. A radiologist evaluated the lumbar lordosis Cobb's angle, the cross-sectional area of the right and left intervertebral foramina and spinal canal at L1-L2, L2-L3, L3-L4 spinal levels. Spinal symptoms were evaluated by the Oswestry Disability Questionnaire. The Cobb angle of lumbar lordosis was found significantly greater on an MRI performed without knee bolster than with bolster (47.30 ± 9.90 vs. 42.57 ± 10.62, p < 0.001). The cross-sectional area of the intervertebral foramina and spinal canal at all evaluated levels was smaller when performed without knee bolster than with bolster. However, differences were significant only at the L1-L2 level and in the spinal canal at all evaluated levels. The Cobb angle, measured with and without knee bolster, showed significant positive correlations with back pain while standing and walking. The spinal canal area without knee bolster showed greater correlations with the Oswestry score parameters than with knee bolster. MR images at evaluated spinal levels taken without knee bolster showed greater correlations of the spinal canal cross-sectional area with the Oswestry score than ones with knee bolster. Thus, one may prefer MR images acquired without a bolster below the knee compared to an MRI with a knee bolster.

The efficacy and complications of minimally invasive vs. the traditional open transforaminal lumbar interbody fusion for the treatment of lumbar spondylolisthesis

Objective To investigate the clinical efficacy and complications of minimally invasive transforaminal lumbarinterbody fusion (TLIF) in the treatment of lumbar spondylolisthesis. Methods Total 142 patients with single level spondylolisthesis who treated by TLIF from 2010.01 to 2015.06 were included in this study, with 68 cases in minimally invasive TLIF (MIS-TLIF) group and 74 cases in traditional open TLIF group. The general information (age, gender, isthmic or degenerative type, percentage of slip degree, levels), operative time, blood loss, length of postoperative hospital stay, Visual Analogue Scale (VAS) of lowback pain and leg pain, and Oswestry Disability Index (ODI) were recorded and collected. The posterior height of the intervertebralpace and segmental lordosis, reduction of spondylolisthesis and cross-sectional area of spinal canal were measured. Results There was no statistically significant difference between the two groups in age, gender ratio, percentage of slip degree, and surgicallevels distribution. Total of 66 cases in MIS-TLIF group and 71 cases in Open TLIF group finished 2 years follow up, and 25 cases in MIS-TLIF group and 31 cases in Open TLIF group finished 5 years follow up. The blood loss of the MIS-TLIF group was 164.7±51.7 ml, significantly lower than the open TLIF group of 239±69.3 ml(P<0.001). The length of postoperative hospital stay was 5.9±1.5 days in MIS-TLIF group, significantly shorter than the open TLIF group of 7.3±3.1 days(P<0.001). The operative time of MIS-TLIF and Open TLIF was 146.3±21.9 mins, 152.0±20.4 mins, respectively, and no significant difference was found between them. The VAS ofback pain, leg pain, ODI in MIS-TLIF group was 1.76±1.16, 1.91±1.36 and 23.5±7.3 at 2 years follow up, and in Open TLIF was 1.73±1.10, 1.83±1.36 and 23.8±6.7, respectively, all of them were significantly different to pre-operation, however, no significant difference was found between two groups. The VAS of back pain, leg pain, ODI in MIS-TLIF group was 1.73±1.21, 1.93±1.48, and 25.4±6.8 at 5years follow up, and in Open TLIF was 1.85±1.02, 1.85±1.33 and 26.1±6.5, respectively, no significant difference between twogroups. The posterior height of the intervertebral space and segmental lordosis of MIS-TLIF was 9.52±1.67 mm and 12.11°±3.44° at 2 years follow up, while the open TLIF was 9.88±1.54 mm and 12.98±3.83°, all of them were significantly different to pre-operation,however, no significant difference between two groups. The posterior height of the intervertebral space and segmental lordosis of MIS-TLIF was 9.37±1.46 mm and 11.55°±2.77°, while the open TLIF was 9.66±1.68 mm and 12.59°±4.23°, no significant difference between two groups. The percentage of slip degree was reduced to 5.2%±4.6% in MIS-TLIF and 5.6%±4.3% in open TLIF, the cross-sectional area of spinal canal was enlarged to 139.7±19.5 mm2 and 141.7±20.7 mm2, no significant difference between two groups either. Conclusion MIS-TLIF has less blood loss, shorter postoperative hospital stay than open TLIF, and similar clinical pain and functional outcomes. MIS-TLIF is suggested to be a safe and effective choice in the treatment of lower grade lumbar spondylolisthesis(Grade II or less). Key words: Lumbar vertebrae; Spondylolysis; Surgical procedures, minimally invasive; Spinal fusion

Wednesday, September 26, 2018 7:35 AM–9:00 AM ePosters

BACKGROUND CONTEXT Common indications for transforaminal lumbar interbody fusion (TLIF) include foraminal stenosis, degenerative disc disease and spondylolisthesis. Although minimally invasive surgical techniques (MIS) for TLIF have been shown to provide adequate postoperative sagittal alignment, it is unclear whether these procedures result in adequate reduction of canal compressive forces. PURPOSE Assess baseline to postoperative changes in cross-sectional canal area in patients undergoing minimally invasive transforaminal lumbar interbody fusion. STUDY DESIGN/SETTING Retrospective clinical review of a prospective surgeon-maintained MIS database. PATIENT SAMPLE A total of 16 patients undergoing MIS TLIF. OUTCOME MEASURES Spinal canal cross-sectional area, stenotic levels. METHODS Consecutive patients >18years undergoing transforaminal lumbar interbody fusion via minimally invasive surgical technique were included. Patients with preoperative lumbar MRIs and postoperative lumbar MRI or CT scans were assessed for spinal canal cross sectional area at operative interspace levels. Stenotic levels were defined as canal cross sectional area RESULTS Overall, 16 patients met inclusion criteria and underwent minimally invasive transforaminal lumbar interbody fusion. Mean patient age was 54.3±12.1years, 63% of patients were female, and mean Charlson Comorbidity Index score was 0.86±1.10. Patients presented with three primary diagnoses: herniated nucleus pulposis (36.8%), stenosis (42.1%) and spondylosis (21.1%). On average, patients underwent fusions spanning 1.69±1.13 levels, and 37.5% of patients underwent multilevel fusion. 93.7% of cases involved laminotomy, 31.3% laminectomy, 81.3% foraminotomy. Mean operative time was 349 minutes and blood loss was 389±486 ccs. From baseline to postoperative intervals, 87.5% of patients showed an increase in mean operative interspace canal cross sectional area, with the overall cohort showing significant improvement in canal cross sectional area (207.6 mm2 to 301.6 mm2, p CONCLUSIONS Following minimally invasive transforaminal lumbar interbody fusion, patients showed a significant increase in spinal canal cross sectional area. This increase in canal cross sectional area corresponded with an overall decrease in the rate of lumbar stenosis, suggesting MIS TLIF procedures have the potential to provide adequate relief of spinal canal compressive forces.

Wednesday, September 26, 2018 7:35 AM–9:00 AM ePosters: P109. Effect of cervical deformity correction on stenosis, spinal canal and cord compression utilizing magnetic resonance and computed tomography imaging modalities

BACKGROUND CONTEXT Cervical deformity (CD), often degenerative in etiology, is typically accompanied by the onset of symptomatic spinal stenosis. It is hypothesized that causation of spinal canal and cord compressive forces is multifactorial, with reduction of compressive forces being a key driver of symptom alleviation. PURPOSE To quantify and assess the relationship between postoperative changes to sagittal alignment, canal or cord decompression, and symptom alleviation. STUDY DESIGN/SETTING Retrospective review of a prospective CD database. PATIENT SAMPLE Twenty-seven CD patients. OUTCOME MEASURES Stenotic Levels, Pavlov Ratio, Spinal Canal Cross-Sectional Area, Spinal Cord Cross-Sectional Area, mJOA scores, NSR Neck Pain scores. METHODS ConsecutiveCD patients (C2–C7 Cobb>10°, CL>10°, cSVA>4 cm, or CBVA>25°) undergoing multilevel fusion. Those with pre-operative magnetic resonance imagings (MRIs) and 1-year post-operative cervical MRI or CT scans were assessed for spinal canal and cord cross-sectional area, using dedicated imaging software at each interspace and body from C2–C7, and the apex of deformity[apex]. Stenotic vertebral levels were measured using Pavlov's method from C2 to C7: a ratio of canal to vertebral body RESULTS A total of 27 patients were included (61±10 years, 64.2%F, BMI: 29.6±8.0, CCI: 0.81±1.1). BL radiographic assessment: TS-CL: 34.0±17.2; Cervical Lordosis: −1.6±15.7; cSVA: 36.3±18.5; PI-LL: 0.12±19.3; Pelvic Tilt: 20.1±11.6; SVA: 0.94±71.6. Ames classification deformity descriptors: C: 57.7%, CT: 30.8%, T: 7.7%, S: 3.8%. Surgical approach included 7.4% anterior, 51.9% posterior, 40.7% combined; 23(79%) patients had decompression procedures, all patients had an osteotomy, and mean fusion length was 8.6±4.2 levels. Following surgical intervention, mean canal cross-sectional area (267.5 mm2 vs. 320.5 mm2, p=.025), apex canal cross-sectional area (240 mm2 vs. 301.3 mm2, p=.039), and apex cord cross-sectional area (60.6 mm2 vs. 70.1 mm2, p=.019) all increased (regardless of decompression procedure status). Decreased stenotic levels (4.11vs. 2.97, p=.003) and improved apex pavlov ratios (0.76vs. 0.91, p=.032) were also observed. Cervical kyphosis correction correlated with Δ in stenotic levels (rs: 0.664, p=.001), Δ in mean C2–C7 pavlov ratio (rs: 0.601, p=.004), and Δ in apex canal area (rs: 0.562, p=.024). TS-CL correction correlated with Δ in stenotic levels (rs: 0.751, p CONCLUSIONS Sagittal realignment was associated with reduction of symptomatic stenosis and cord compressive forces, regardless of decompression status. Stenotic level reduction was associated with improved mJOA scores, while alleviation of dynamic radial compressive forces at the apex of deformity significantly reduced patient neck pain.

Comparison of Clinical and Radiologic Results of Mini-Open Transforaminal Lumbar Interbody Fusion and Extreme Lateral Interbody Fusion Indirect Decompression for Degenerative Lumbar Spondylolisthesis.

Study DesignRetrospective study.PurposeIn this study, we compared the postoperative outcomes of extreme lateral interbody fusion (XLIF) indirect decompression with that of mini-open transforaminal lumbar interbody fusion (TLIF) in patients with lumbar degenerative spondylolisthesis.Overview of LiteratureThere are very few reports examining postoperative results of XLIF and minimally invasive TLIF for degenerative lumbar spondylolisthesis, and no reports comparing XLIF and mini-open TLIF.MethodsForty patients who underwent 1-level spinal fusion, either by XLIF indirect decompression (X group, 20 patients) or by mini-open TLIF (T group, 20 patients), for treatment of lumbar degenerative spondylolisthesis were included in this study. Invasiveness of surgery was evaluated on the basis of surgery time, blood loss, hospitalization period, and perioperative complications. The Japanese Orthopedic Association Back Pain Evaluation Questionnaire (JOABPEQ), disc angle (DA), disc height (DH), and slipping length (SL) were evaluated before surgery, immediately after surgery, and at 12 months after surgery. Cross-sectional spinal canal area (CSA) was also measured before surgery and at 1 month after surgery.ResultsThere was no significant difference between the groups in terms of surgery time or hospitalization period; however, X group showed a significant decrease in blood loss (p<0.001). Serious complications were not observed in either group. In clinical assessment, no significant differences were observed between the groups with regard to the JOABPEQ results. The change in DH at 12 months after surgery increased significantly in the X group (p<0.05), and the changes in DA and SL were not significantly different between the two groups. The change in CSA was significantly greater in the T group (p<0.001).ConclusionsPostoperative clinical results were equally favorable for both procedures; however, in comparison with mini-open TLIF, less blood loss and greater correction of DH were observed in XLIF.