Disc Height Ratio Research Articles

Clinical and Radiologic Comparisons Between Oblique Lumbar Interbody Fusion Combined with Percutaneous Pedicle Screw Fixation and Transforaminal Lumbar Interbody Fusion for Adult Isthmic Spondylolisthesis: A 2-year Follow-Up Study

Adult isthmic spondylolisthesis(AIS) results in the anterior translation of the vertebral body with neural encroachment. Although oblique lumbar interbody fusion(OLIF) is minimally invasive technique that use a retroperitoneal plane to achieve indirect decompression compared to transforaminal lumbar interbody fusion(TLIF), research on OLIF for AIS remains limited. Therefore, we aimed to compare the clinical and radiological outcomes of these two surgical techniques for AIS. We analyzed the details of 62patients with AIS who were treated with either OLIF(n=26) or TLIF(n=36) between 2019 and 2022, with a minimum 2-year follow-up. The two surgical techniques were compared in terms of perioperative surgical, radiological, and clinical outcomes. The correlation between the severity of foraminal stenosis and clinical outcomes was evaluated. The OLIF group experienced significantly less blood loss, shorter operative times, and shorter hospital stay than the TLIF group. Radiological assessments showed no significant preoperative differences in disc height or slippage ratios, but postoperative slippage correction was significantly greater in the OLIF group than in the TLIF group(13.5±8.0 versus 5.0±8.9; p<0.001). The clinical outcome improvement ratios did not differ significantly between the two groups. The correlation between preoperative severity of foraminal stenosis and clinical outcomes in the OLIF group was not significant. OLIF is more advantageous than TLIF in terms of blood loss, operative time, hospital stay and anterolisthesis correction. In addition, good clinical outcomes were obtained with indirect decompression alone, regardless of the severity of foraminal stenosis. Therefore, OLIF is a good surgical option for the treatment of AIS.

Three-dimensional fiber patterning in the annulus fibrosus can be derived from vertebral endplate topography.

The annulus fibrosus (AF) of the Intervertebral disc (IVD) is composed of concentric lamellae of helically wound collagen fibers. Understanding the spatial variation of collagen fiber orientations in these lamellae, and the resulting material anisotropy, is crucial to predicting the mechanical behavior of the complete IVD. This study builds on a prior model predicated on path-independent displacement of fiber endpoints during vertebral body growth to predict a complete, three-dimensional annulus fibrosus fiber network from a small number of subject-independent input parameters and vertebral endplate topographies obtained from clinical imaging. To evaluate the model, it was first fit to mid-plane fiber orientations obtained using polarized light microscopy in a population of bovine caudal discs for which computed tomography images vertebral endplates were also available. Additionally, the model was used to predict the trajectories based on human lumbar disc geometries and results were compared to previously reported data. Finally, the model was employed to investigate potential disc-related variations in fiber angle distributions. The model was able to accurately predict experimentally measured fiber distributions in both bovine and human discs using only endplate topography and three input parameters. Critically, the model recapitulated previously observed asymmetry between the inclinations of right- and left-handed fibers in the posterolateral aspect of the human AF. Level to level variation of disc height and aspect ratio in the human lumbar spine was predicted to affect absolute values of fiber inclination, but not this asymmetry. Taken together these results suggest that patient-specific distributions of AF fiber orientation may be readily incorporated into computational models of the spine using only disc geometry and a small number of subject-independent parameters.

The Effect of Interbody Cage Parameters on the Rate of Subsidence in Single-Level Anterior Cervical Discectomy and Fusion (ACDF): A Retrospective Analysis of 98 Patients.

Subsidence is arelatively common consequence after anterior cervical discectomy and fusion (ACDF) surgery. This study aimed to identify the effect of radiological and non-radiological risk factors on subsidence after a single-level ACDF surgery with cage and plate. This is a retrospective cohort study of patients who underwent ACDF for radiculopathy or myelopathy at an academic center, University of Kentucky Albert Chandler Hospital, Lexington, Kentucky, United States, between January 2010 and January 2020.Subsidence was defined as the sinking of the interbody cage into the vertebral body at either the superior end plate (SEP) or inferior end plate (IEP) at the ACDF level and was measured manually on lateral standing x-ray. The numerical amount of subsidence was measured in millimeters as the sum of subsidence in the SEP and IEP and was further categorized into subsidence2 and subsidence3 (i.e., presence of subsidence > 2 mm and subsidence > 3 mm, respectively). Multivariateregression analysis was used to assess the effect of variables such as age, gender, body mass index (BMI), tobacco use, follow-up length, cage type, anterior cage height, posterior cage height, anterior cage height ratio, posterior cage height ratio, cage position, cage-end plate interface and cervical alignment on outcomes such as subsidence, subsidence2, and subsidence3. A total of 98 patients were included, of which 46 (47.1%) were male. The mean age of the population was 47.6±8.4 years. Fifty-one patients (52%) experienced subsidence more than 3 mm. Anterior disc height ratio (ADHR) was calculated by dividing the anterior cage height by the anterior disc height (pmADH). The posterior disc height ratio (PDHR) was calculated by dividing the posterior cage height by the posterior disc height (pmPDH). There was no significant correlation between ADHR and PDHR with subsidence, (p=0.93 and 0.56, respectively). Gender, age, BMI, and smoking status did not affect subsidence either. Cage type significantly affected subsidence with a higher subsidence rate in VG2 cages compared to Bengal cages (p=0.05). This study showed that in patients undergoing single-level ACDF with cage and plate, cage size and in particular cage height (if adjusted for individual patients) did not affect subsidence. Other factors such as cage-endplate interface, cage depth in interbody space, and cervical alignment did not significantly affect subsidence either. This might be attributable to the use of an anterior plating system that conducts the force and reduces the stress on the graft-bone interface.

Changes in Disc Height as a Prognostic Factor in Patients Undergoing Microscopic Discectomy.

Some patients with disc herniation who underwent discectomy complain of back pain after surgery and are unsatisfied with the surgical results. This study aimed to evaluate the relationship between preoperative disc height (DH), postoperative DH, and pain score 12 months after surgery in patients who underwent microdiscectomy for herniated lumbar disc. This study enrolled patients who underwent microdiscectomy at a medical center between January 2012 and December 2020. Patients with X-ray or computed tomography and pain score assessment (visual analog scale score) prior to surgery, immediately post-op, and at 1, 6, and 12 months after surgery were included. The DH index was defined as DH/overlying vertebral width. The DH ratio was defined as the postoperative DH/preoperative DH. Simple linear regression and multivariate linear regression analyses were applied to assess the correlation between DHs and leg pain scores 12 months after surgery. A total of 118 patients who underwent microdiscectomy were included. DH decreased up to 12 months after surgery. The DH ratio at 1, 6, and 12 months after discectomy showed a significant positive correlation with the pain scores at 12 months after discectomy (1 month : p=0.045, B=0.52; 6 months : p=0.008, B=0.78; 12 months : p=0.005, B=0.69). Multivariate linear regression analysis revealed that the level of surgery, sex, age, and body mass index had no significant relationship with back pain scores after 12 months. In patients who underwent microdiscectomy, the DH ratios at 1, 6, and 12 months after surgery were prognostic factors for back pain scores at 12 months after surgery. Aggressive discectomy is recommended for lower postoperative DH ratios and Visual analog scale scores, leading to improved patient satisfaction.

Spondilolysthesis L5-S1: An Original Article

Objectives: To assess the clinical, functional and radiological outcome of Posterior Lumbar Interbody Fusion (PLIF) by Banana cage with bone graft. Material and Methods: This retrospective analytical study was carried out in unit of Orthopaedic surgery department from January 2010 to December 2020. We did PLIF by Banana cage with bone graft for High-grade Lumbar Spondylolisthesis at L5-S1. The follow up period ranges from 1 year to 2 years (average 18 months). Within these follow up period we have assessed the patients clinically, functionally and radiologically. All patients were assessed by Visual Analogue Score (VAS), Oswestry Disability Index (ODI), Waddell Disability Index (WDI), Spino-pelvic parameters, Modified Macnab’s Criteria to find out overall outcome and Hackenberge ctriteria for radiological fusion. Results and Conclusions: Total 40 patients were included among them 16were male and 24 were female. The average age of the patients was 52.45±10.1 years. Maximum (60.0%) patients were housewife followed by 20.0%, 10.0%, 10% were day laborer, farmer and service holder respectively. Average pelvic tilt was 26.05±6.27° preoperatively and 24.10±6.26° at the final follow-up, average PI was 66.07±7.39° preoperatively and 61.19±7.08° at the final follow-up. Preoperative lumbar lordosis was 45.55±6.71° with postoperatively 37.29±6.19°at final follow-up. VAS score and ODI scales were improved significantly from preoperative 6.90±6.16 and 57.60±15.66, respectively, to postoperatively and final follow-up 2.0±0.8 and 7.60±2.40, respectively. Pre-operative Translation ratio, slip angle and disc height ratio were 21.96±10.25, -18.87±8.28, 11.03±4.36 respectively and postoperatively 13.17±6.57, -18.44±7.12, 19.60±3.36 respectively. Fusion was achieved in 36 cases (90%), 3 cases (7.5%) were fragmented and pseudoarthrosis showed only 1 case (2.5%). Most of the study population according to post operative clinical outcome showed excellent outcome (95%), 1 (2.5%) case had good and 1 (2.5%) case had fair outcome. Conclusion: It can be concluded that, Posterior Lumbar Interbody Fusion (PLIF) by Banana cage with bone graft can be a very good option for the treatment of High-grade Lumbar Spondylolisthesis at L5-S1 levels.

Similarity and difference between aging and puncture-induced intervertebral disc degeneration.

The purpose of our study was to investigate the changes in micromorphology and mechanical properties of intervertebral discs degeneration induced by aging and puncture. Normal group (NG), 2 weeks post-puncture degeneration group (PDG) and aging degeneration group (ADG) each included 10 rats. Plain film, magnetic resonance imaging, and histological testing were utilized to assess intervertebral disc degeneration. Atomic force microscope was utilized to analyze the microstructure and elastic modulus of the intervertebral disc, while immunohistochemistry was employed to assess alterations in the cell matrix using collagen I, collagen II, matrix metalloproteinase-3 (MMP-3), and tumour necrosis factor-α (TNF-α). The results showed that the disc height ratio between PDG and ADG decreased. In the PDG and ADG group, histological scores both increased, the gray value of the T2 signal decreased, the proportion of MMP-3 and TNF-positive cells in intervertebral disc tissues was higher (p < 0.05) and the IOD values of COL-2 lower in intervertebral disc tissues (p < 0.05). The elastic modulus of PDG and ADG annulus fibers (AF) increased compared to the NG (p < 0.05); when compared to PDG, the elastic modulus of ADG AF decreased (p < 0.05). The elastic modulus of PDG and ADG collagen increased in the nucleus pulposus (NP, p < 0.05); ADG had a greater AF diameter than NG and PDG (p < 0.05). The results indicated that ADG fiber diameter thickens, and chronic inflammation indicators rise; PDG suffers from severe extracellular matrix loss. The degeneration of the ADG and PDG intervertebral discs is different. The results provide foundation for clinical research.

Depression is associated with worse outcome after percutaneous endoscopic lumbar discectomy: a 5-year follow-up study

ABSTRACT This study aimed to investigate the relationship between depression and outcome of percutaneous endoscopic lumbar discectomy (PELD) in patients with lumbar disc herniation. We examined 268 patients who underwent PELD for lumbar disc herniation and were followed for five years. Patients were grouped according to mood: normal mood (159 patients) and continuous depression (109 patients). Depressive symptoms were assessed using the 21-item Beck Depression Inventory. Back and leg pain were assessed using the visual analogue scale. Subjective disability was measured using the Oswestry Disability Index. Neurological function and physical disability were assessed using the Japanese Orthopaedic Association score. Disc-height ratio and intervertebral instability were measured to assess lumbar stability. Clinical and radiological data were recorded before surgery and at the 3-month, 6-month, 1-year, 2-year, and 5-year follow-ups. Although the Japanese Orthopaedic Association, visual analogue scale, and Oswestry Disability Index scores did not significantly differ between groups before surgery, all three scores significantly differed between groups at all follow-up time points after PELD (p < 0.05). Measurements of disc-height ratio and intervertebral instability did not significantly differ between the groups before surgery nor at any point after surgery (P > 0.05). Patients with continuous depression exhibited less improvement in symptom severity and disability score after PELD at all time points in the five years after surgery. Depression had little effect on lumbar vertebral stability after PELD. Interventions to detect and treat depression should be performed before and after surgery.

Clinical, Functional and Radiological Outcome of Posterior Lumbar Interbody Fusion by Banana Cage with Bone Graft for the Treatment of High-grade Lumbar Spondylolisthesis at L5-S1

Objectives: To assess the clinical, functional and radiological outcome of posterior lumbar interbody fusion (PLIF) by Banana cage with bone graft. Material and Methods: This retrospective analytical study was carried out in spine unit of Orthopaedic surgery department of BSMMU, and other private hospital in Dhaka from January 2010 to December 2020. We did PLIF by Banana cage with bone graft for High-grade Lumbar Spondylolisthesis at L5-S1. The follow-up period ranges from 1- 2 years (average 18 months. All patients were assessed by VAS, ODI, WDI, Spino-pelvic parameters, Modified Macnab’s Criteria to find out overall outcome and Hackenberge ctriteria for radiological fusion. Results: Total 40 patients were included among 16 were male and 24 were female. The average age of the patients was 52.45±10.1 years. 60.0% patients were housewife ,20.0%, 10.0%, 10% were day laborer, farmer and service holder respectively. Average pelvic tilt was 26.05±6.27° preoperatively and 24.10±6.26° at the final follow-up, average PI was 66.07±7.39° preoperatively and 61.19±7.08° at the final follow-up. Preoperative lumbar lordosis was 45.55± 6.71° &amp; at final follow-up 37.29±6.19°. VAS score and ODI scales were improved significantly from preoperative 6.90 ± 6.16 and 57.60±15.66 to at final follow-up 2.0±0.8 and 7.60±2.40. Pre-operative Translation ratio, slip angle and disc height ratio were 21.96±10.25, -18.87±8.28, 11.03±4.36 and at postoperatively 13.17±6.57, -18.44±7.12, 19.60±3.36. Fusion was achieved in 36 cases (90%), 3 cases (7.5%) were fragmented and pseudoarthrosis showed only 1 case (2.5%). Post-operative clinical outcome showed excellent outcome (95%), 1 (2.5%) case had good and 1 (2.5%) case had fair outcome. Conclusion: It can be concluded that, PLIF by Banana cage with bone graft is a very good option for the treatment of High-grade Lumbar Spondylolisthesis at L5-S1 levels. Keywords: Posterior Lumbar Interbody Fusion, High-grade Spondylolisthesis, Visual Analogue Score, Oswestry Disability Index, Waddell disability index, Hackenberge criteria, Pelvic parameters.

The Effect of L5-S1 Degenerative Disc Disease on Outcomes of L4-L5 Fusion.

Retrospective cohort study. The aim was to investigate the clinical relevance of preoperative caudal adjacent segment degeneration (ASD) in patients undergoing isolated L4-5 fusion to determine a threshold of degeneration at which a primary L4-S1 fusion would be warranted. Increased motion and biomechanical forces across the adjacent caudal segment in isolated L4-L5 fusion leads to concerns regarding the increased incidence of revision surgery because of the development of ASD. Patients who underwent isolated L4-L5 fusion between 2014 and 2019 were reviewed. Pfirrmann grading and the disc heights of the caudal level relative to the rostral level were used to quantify preoperative adjacent degenerative disc disease. To assess the influence of preoperative caudal degenerative disc disease, preoperative disc height ratios (DHRs) were compared for patients who reported minimal, moderate, and severe Oswestry disability index (ODI) sores on postoperative assessment. For each patient-reported outcome measure (PROM), adjacent DDD was compared for those who did and did not meet MCID. An area under curve analysis was used to identify a threshold of degeneration impacting outcomes from the preoperative DHR. A total of 123 patients were studied with an average follow-up of 2.11 years. All patients demonstrated a significant improvement in all PROMs after surgery. When categorizing patients based on the severity of postoperative ODI scores, there were no preoperative differences in the L5-S1 Pfirrmann grading or DHRs. There was a significant association between greater preoperative anterior DHR and an increased number patients who met MCID for visual analog scale back. There were no radiographic differences in preoperative L5-S1 Pfirrmann grade or DHR for ODI, visual analog scale leg, MCS-12, or PCS-12. area under curve analysis was not able to identify a preoperative DHR threshold that reflected worse MCID for any PROM. No preoperative radiographic indicators of caudal ASD were predictive of worse clinical outcomes after isolated L4-5 fusion. Level III.

The increased motion of lumbar induces ligamentum flavum hypertrophy in a rat model

BackgroundThe purpose of this study was to establish a novel rat model for ligamentum flavum (LF) hypertrophy using increased motion of lumbar and to elucidate the etiology of (LFH).MethodsA total number of 30 male rats were used. The increased motion of lumbar was induced by surgical resection of L5/6 posterior elements (n = 15). The other rats underwent a sham operation (n = 15). After 8 weeks, all rats were taken lateral plain X-rays. The LF from L5/6 in both groups were harvested to investigate histological, immunohistological, and real-time PCR analysis.ResultsAccording to radiological results, the disc height ratio, flexion ratio, and extension ratio were larger in the rats in the experimental group than that of in the sham group. The HE staining showed that the LF thickness in the experimental group significantly increased in comparison to the sham group. The Masson trichrome staining showed that the ratio of elastic fibers to collagen fibers in experimental group was lower than that in the sham group. The protein and gene expression of TGF-β1, TNF-α, IL-1β, and Col 1 were significantly higher in the experimental group than that in the sham group.ConclusionA relatively safe, simple, and rapid rat model of LFH using increased motion of lumbar was established. The increased motion of lumbar could lead to high expression of inflammatory and fibrotic factors in LF, causing the accumulation of collagen fibers and decreasing of elastic fibers.

A modified method to treat severe asymptomatic pre\u2010existing degeneration of adjacent segment: a retrospective case\u2010control study

BackgroundPre-existing degeneration of adjacent segment is an important risk factor for adjacent-segment degeneration (ASD), but only limited and controversial studies have addressed its management.Methods We retrospectively analyzed patients with symptomatic degeneration of the L5/S1 segment warranting surgical interference and severe asymptomatic degeneration of the L4/5 segment. Of these patients, those who underwent interbody fusion of the causative (L5/S1) segment and distraction of the intervertebral space and facet fusion of the adjacent L4/5 segment were included in Group A (n = 103), while those who underwent interbody fusion of both the L5/S1 and L4/5 segments were included in Group B (n = 81). Clinical and radiographic outcomes were evaluated.ResultsMean follow-up time was 58.5 months (range, 48–75 months). We found no significant difference in clinical outcomes or incidence of ASD in the L3/4 segment between Groups A and B. Compared with Group B, Group A experienced less bleeding (315 ± 84 ml vs. 532 ± 105 ml), shorter operation time (107 ± 34 min vs. 158 ± 55 min) and lower costs (US $13,830 ± $2640 vs. US $16,020 ± $3380; P < 0.05). In Group A, the disc height ratio (DHR) of the L4/5 segment was significantly increased from a preoperative value of 0.40 ± 0.13 to a last–follow-up value of 0.53 ± 0.18 (P < 0.05), while the degree of canal stenosis (DCS) was decreased from a preoperative value of 34.3 ± 11.2% to a last–follow-up value of 15.9 ± 9.3 % (P < 0.05).ConclusionsThis modified method could be effective in treating severe asymptomatic pre-existing degeneration of adjacent segment in the lumbar spine.

Minimum Seven-Year Follow-Up Outcomes of Percutaneous Endoscopic Lumbar Discectomy for Lumbar Degenerative Disease.

PurposeTo investigate the long-term (> 7 years) clinical outcomes of percutaneous endoscopic lumbar discectomy for lumbar degenerative disease to address postoperative problems including postoperative dysesthesia (POD), residual back pain and segmental instability.MethodsInclusion and exclusion criteria were established. All patients who met the above criteria were treated by PELD using the transforaminal approach. Limited discectomy was performed to preserve the disc material in the intervertebral space as much as possible. The Oswestry Disability Index (ODI), Japanese Orthopaedic Association (JOA) score, visual analog scale (VAS) score for back pain (VAS-B) and leg pain (VAS-L) and Modified MacNab’s criterion were used for clinical evaluation. Radiographic parameters including height of intervertebral disc and segmental instability were also evaluated.ResultsForty-two patients (24 men and 18 women) who met our inclusion and exclusion criteria were included in our study. The average follow-up period was 95.71±5.63 months (ranging from 87 to 105 months). There were no neurological complications associated with the operation. POD was found in 14.29% of patients, while only 2 patients (4.76%) complained of mild dysesthesia at final follow-up. Two patients (4.76%) required revision surgery during the follow-up period. The final follow-up ODI, JOA score, VAS-B and VAS-L were significantly better than preoperative values. The average disc-height ratio was 84.52±5.66% of the preoperative disc height. No instability at the operation level was noted at final follow-up.ConclusionOur study showed that PELD using the transforaminal approach can provide favorable results after a long-term follow-up period. POD is a common complication at initial prognosis. Limited discectomy can preserve the disc height well and minimize the risk of residual back pain.

Follow-up results of microendoscopic discectomy compared to day surgery using percutaneous endoscopic lumbar discectomy for the treatment of lumbar disc herniation

BackgroundPercutaneous endoscopic lumbar discectomy (PELD) is satisfactory for hospitalized patients with lumbar disc herniation (LDH). Currently, only a few studies have reported about the day surgery patients undergoing PELD.MethodsA total of 267 patients with LDH underwent PELD during day surgery and were followed up for at least 3 years. Clinical outcomes were assessed using the visual analog scale (VAS) for leg and lower back pain (VAS-B and VAS-L, respectively) and the Oswestry disability index (ODI). The radiological outcomes, such as lumbar lordosis (LL), sacral slope (SS), the disc-height ratio, and disc instability, were recorded and compared. The clinical effects between patients treated by PELD during day surgery and microendoscopic discectomy (MED) for contemporaneous hospitalized 116 patients with LDH were compared.ResultsPatients treated by PELD had lower blood loss and shorter hospital stay (P < 0.001) compared to those treated by MED. VAS-L, VAS-B, and ODI decreased significantly after PELD than before the operation and 3 years postoperatively. The postoperative VAS-B in the PELD group was significantly decreased than in the MED group (P = 0.001). The complications rate was 9.4% in the PELD group and 12.1% in the MED group (P = 0.471). The 1-year postoperative recurrence rate in the PELD group was much higher than that in MED group (P = 0.042). The postoperative LL and SS in the PELD group improved significantly compared to the values in the MED group (P < 0.001). According to the disc-height ratio at 3-year follow-up, a significant height loss was observed in the MED group than in the PELD group (P = 0.014).ConclusionsAlthough the 1-year postoperative recurrence rate was relatively high, the day surgery for LDH undergoing PELD had advantages in terms of less blood loss intraoperatively, short hospital stay, efficacy for back pain, and efficiency to maintain lumbar physiological curvature.

Clinical Outcomes of Interlaminar Percutaneous Endoscopic Decompression for Degenerative Lumbar Spondylolisthesis with Spinal Stenosis.

The use of traditional open decompression alone in degenerative spondylolisthesis can lead to the development of postoperative spinal instability, whereas percutaneous endoscopic decompression can preserve the attachment of intervertebral muscles, facet joint capsules, and ligaments that stabilize the spine. The study’s aim was to determine clinical as well as radiologic outcomes associated with interlaminar percutaneous endoscopic decompression in patients with stable degenerative spondylolisthesis. For this study, 28 patients with stable degenerative spondylolisthesis who underwent percutaneous endoscopic decompression were enrolled. The clinical outcomes in terms of the visual analogue scale (VAS) and Oswestry disability index (ODI) were evaluated. Radiologic outcomes were determined by measuring the ratio of disc height and the vertebral slippage percentage using lateral standing radiographs. The average follow-up period was 25.24 months. VAS and ODI were significantly improved at the final follow-up. In terms of ratio of disc height and vertebral slippage percentage found no significant difference between the preoperative and postoperative periods. One patient underwent further caudal epidural steroid injection. One patient underwent fusion because their radicular pain did not improve. Interlaminar percutaneous endoscopic decompression is an effective procedure with favorable outcomes in selected patients with stable degenerative spondylolisthesis.

Decade-Wise Computed Tomography-Based Morphometric Measurements of a Single Lumbar Spinal Motion Segment L4-5.

A spinal motion segment comprises facet joints and intervertebral disc. A complex interplay of biomechanical factors occurs between them with degeneration giving rise to numerous pathological conditions. We conducted a study to find a correlation between facet joint orientation and intervertebral discs with age. A cross-sectional study of 203 consecutive subjects undergoing a computed tomography scan of abdomen and pelvis were included. Subjects were divided into 5 groups based on age (group I: 18-30 years; group II: 31-40 years; group III: 41-50 years; group IV: 51-60 years; group V: 61-70 years). Using 3-dimensional reconstruction images, orientation of lumbar facet joints at the L4-5 level was measured. Similarly, adjacent disc heights at L3-4 and L4-5 were measured and their ratio was documented. The study included 106 males and 97 females. A positive correlation was noted between age and sagittal facet orientation until age 60 years. However, after age 60 years, a negative correlation with age was seen, which was statistically significant. Similarly, the disc height ratios show a progressive decline in their values with age. However, this decline was statistically significant only after age 60 years. The gradual change of facet joint orientation from sagittal to coronal as the age crosses from 30 to 60, to beyond 60, with a simultaneous and parallel diminishing in the disc height probably is one of the attributes of the phenomenon of autostabilization of a motion segment.

Does “Coronal Root Angle” Serve as a Parameter in the Removal of Ventral Factors for Foraminal Stenosis at L5-S1 In Stand-alone Microendoscopic Decompression?

Prospective single-center cohort study. The present study aims to investigate the causes of failure of L5/S1 foraminal stenosis, and it is hypothesized that the newly defined "L5 coronal root angle (CRA)" may be a parameter in the removal of ventral pathologies. Lumbar foraminal stenosis is an important cause of recurrent leg pain after central spinal stenosis surgery. Although it can be seen at all levels, L5/S1 is the level at which it is most frequently seen due to its specific characteristics, with success rate is lower than other levels after foraminal decompression. L5/S1 microendoscopic foraminal decompression was performed to 51 patients. According to Japanese Orthopedic Association (JOA) improvement at 12-month follow-up, those with improvement >20% were classified as Group 1 and <20% were classified as Group 2. The patients who underwent discectomy in addition to foraminotomy formed Group 3. Lumbar lordosis angle, segmental lordosis angle, anterior disc height, pelvic tilt, pelvic incidence, sacral slope, relative disc height ratio, pedicle height/vertebral body height ratio, L5 depth, L5 CRA, and anterior disc height/ posterior disc height ratio parameters were measured with lumbar radiographic views, computed tomography (CT), and magnetic resonance imaging (MRI). Among the parameters compared between groups, L5 CRA, posterior disc height, anterior disc height/posterior disc height, relative disc height ratio, and lumbar lordosis angle during extension were seen to be statistically significantly related with low success rate. Failure to remove the ventral pathologies when the L5 CRA is <112. 1º may lead to failed results. Besides, in cases wherein the posterior disc height is <2.85 mm or the anterior/posterior disc height ratio is >3.98, approaches to restoring disc height rather than stand-alone posterior decompression may reduce the possibility of failure. 2.

Relationship Between Intervertebral Disc Morphology and Adolescent Idiopathic Scoliosis

Adolescent idiopathic scoliosis (AIS) is an abnormal 3-dimensional curvature of the spine that appears in youth. In progressive cases, a small curve may be augmented rapidly and leads the victim to a high-risk surgical operation. Recognition of the AIS in the early stage can help in treating it with noninvasive methods. The goal of the study was to examine the relationship between intervertebral disc morphology and AIS as an applicable index and useful method for developing the screening and recognition of AIS before the start of disease. Based on a biomechanical model, we examined the relationship between AIS and intervertebral disc morphology in the thoracic and lumbar region separately and comparatively. For this purpose, the mean disc height (MDH) in the thoracic (MDHT) and lumbar (MDHL) regions and mean ratio of disc height per vertebral radius (MDHPVR) in the thoracic (MDHPVRT) and lumbar (MDHPVRL) regions were compared between 20 girls with AIS and 20 normal girls as the control group by using magnetic resonance imaging. Although there was a significant difference between the AIS and control group in MDHT (P = .004) and MDHPVRT (P = .006), this difference was more significant in the lumbar region (MDHL, P &lt; .0001, and MDHPVRL, P &lt; .0001). According to obtained results, the relation of MDHPVR and scoliosis can be established and used to develop as a screening method for diagnosis and treatment of adolescents who are exposed to scoliosis disorder at an early stage.

Risk factors of instrumentation failure and pseudarthrosis after stand-alone L5-S1 anterior lumbar interbody fusion: a retrospective cohort study.

L5-S1 stand-alone anterior lumbar interbody fusion (ALIF) is a reliable technique to treat symptomatic degenerative disc disease but remains controversial for treatment of isthmic spondylolisthesis. In the present study the authors aimed to identify risk factors of instrumentation failure and pseudarthrosis after stand-alone L5-S1 ALIF and to evaluate whether instrumentation failure influenced the rate of fusion. The study included 64 patients (22 [34.4%] male and 42 [65.6%] female, mean age 46.4 years [range 21-65 years]) undergoing stand-alone L5-S1 ALIF using radiolucent anterior cages with Vertebridge plating fixation in each vertebral endplate. Clinical and radiographic data were reviewed, including age, sex, pelvic parameters, segmental sagittal angle (SSA), C7/sacro-femoral distance (SFD) ratio, C7 sagittal tilt, lumbar lordosis (LL), segmental LL, percentage of L5 slippage, L5-S1 disc angle, and posterior disc height ratio. Univariate and multivariate analyses were used to identify risk factors of instrumentation failure and pseudarthrosis. At a mean follow-up of 15.9 months (range 6.6-27.4 months), fusion had occurred in 57 patients (89.1%). Instrumentation failure was found in 12 patients (18.8%) and pseudarthrosis in 7 patients (10.9%). The following parameters influenced the occurrence of instrumentation failure: presence of isthmic spondylolisthesis (p < 0.001), spondylolisthesis grade (p < 0.001), use of an iliac crest bone autograft (p = 0.04), cage height (p = 0.03), pelvic incidence (PI) (p < 0.001), sacral slope (SS) (p < 0.001), SSA (p = 0.003), and LL (p < 0.001). Instrumentation failure was statistically linked to the occurrence of L5-S1 pseudarthrosis (p < 0.001). On multivariate analysis, no risk factors were found. L5-S1 isthmic spondylolisthesis and high PI seem to be risk factors for instrumentation failure in case of stand-alone L5-S1 ALIF, findings that support the necessity of adding percutaneous posterior pedicle screw instrumentation in these cases.

Normal aging of the lumbar spine in women.

Lumbar lordosis is required for bipedalism. To investigate age-related changes in lumbar lordosis and to clarify the relationships between lumbar lordosis and vertebral wedging and disc degeneration. A total of 300 women were included in this retrospective study, 50 in each of six age groups (20-, 30-, 40-, 50-, 60- and 70-year-olds). Patients with vertebral collapse, instable fracture or disc sequestration were excluded. In each patient, lumbar lordosis angle, posterior vertebral wedging, L5-S1 intervertebral disc angle, L5/L1 vertebral height ratio and L5-S1 intervertebral disc/L1-L2 intervertebral disc height ratio were examined. Significance level was set at p< 0.05 and two-sided tests were used. Significant differences were found in lumbar lordosis according to age group (p< 0.001). Lumbar lordosis correlated most strongly with L4 posterior vertebral wedging, L5 posterior vertebral wedging and L5-S1 intervertebral disc angle, in that order (r= 0.50, r= 0.40, r= 0.32, respectively; p< 0.001). In this cohort, strong spinal structure was maintained during physiological aging from 20 to 40 years of age; lumbar lordosis increased by 50 years of age. Increased lordosis correlated with increased posterior vertebral wedging and loss of posterior disc height.

Radiological Parameters of Undegenerated Cervical Vertebral Segments in a Korean Population.

BackgroundSeveral scoring systems for cervical disc and facet joint degeneration, using radiography or computed tomography, have been developed and tested for reliability. However, definitions of disc height and facet joint space narrowing vary. To our knowledge, no study has reported quantitative data for normal radiologic values of the cervical spine in the Korean population. The purpose of this study is to determine normal cervical disc height, disc height ratio, and facet joint space values, and investigate the correlation between demographic data and these values.MethodsWe performed a retrospective study of patients who underwent artificial disc replacement of the cervical spine. Disc heights and facet joint spaces were measured using cervical neutral lateral radiographs and computed tomography. The means, standard deviations, and 95% confidence intervals of the values were determined.ResultsWe measured 148 intervertebral discs and 352 posterior facet joints. The mean disc height measured by plain radiography and computed tomography was 5.57 ± 0.81 mm and 4.94 ± 0.94 mm, respectively. The mean facet joint space values measured by plain radiography and computed tomography were 1.94 ± 0.45 mm and 1.43 ± 0.39 mm, respectively. The disc heights and facet joint space values measured by plain radiography were greater than those measured by computed tomography. The lower limit of the 95% confidence interval of the disc height ratio calculated by plain radiography and computed tomography was greater than 0.94 at all levels except for C5–6. Patient height and disc height showed a tendency of positive correlation.ConclusionsIn a Korean population, the normal cervical disc height was about 5.0 mm and the normal facet joint space was 1.4 mm. Disc height ratio can reliably identify normal cervical disc height in patients with mild degeneration. Patient height was positively correlated with disc height and facet joint space. Thus, when selecting a cervical implant, surgeons should consider patient height as well as estimated normal disc height.