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Biomaterials, such as hydrogels, have an increasingly important role in the development of regenerative approaches for the intervertebral disc. Since animal models usually resist biomaterial injection due to high intradiscal pressure, preclinical testing of the biomechanical performance of biomaterials after implantation remains difficult. Papain reduces the intradiscal pressure, creates cavities within the disc, and allows for biomaterial injections. But papain digestion needs time, and cadaver experiments that are limited to 24 h for measuring range of motion (ROM) cannot not be combined with papain digestion just yet. In this study, we successfully demonstrate a new organ culture approach, facilitating papain digestion to create cavities in the disc and the testing of ROM, neutral zone (NZ), and disc height. Papain treatment increased the ROM by up to 109.5%, extended NZ by up to 210.9%, and decreased disc height by 1.96 ± 0.74 mm. A median volume of 0.73 mL hydrogel could be injected after papain treatment, and histology revealed a strong loss of proteoglycans in the remaining nucleus tissue. Papain has the same biomechanical effects as known from nucleotomies or herniations and thus creates a disc model to study such pathologies in vitro. This new model can now be used to test the performance of biomaterials. [ABSTRACT FROM AUTHOR]

Introduction: Despite that lateral lumbar interbody fusion (LLIF) is a minimally invasive surgery, some patients complain of severe site pain immediately after the surgery. This study aimed to explore the extent of perioperative pain after LLIF, compare the degree of perioperative pain after LLIF with that after other surgical procedures, and evaluate the factors associated with severe pain in the early postoperative period. Methods: In this study, 93 patients who underwent lumbar spine surgeries for lumbar degenerative diseases were analyzed. The patients were categorized into three groups based on the surgical procedure: Group L, LLIF with percutaneous pedicle screw (PPS); Group P, posterolateral fusion (PLF) or posterior lumbar interbody fusion (PLIF); and Group D, posterior decompression (fenestration). The extent of low back pain was evaluated using the visual analog scale (VAS) preoperatively and from postoperative days 1 to 14. Results: The VAS score for postoperative pain decreased in a time-dependent manner in all three groups (P

Abstract Purpose This study investigated potential use of computed tomography (CT)-based parameters in the lumbar spine as a surrogate for magnetic resonance imaging (MRI)-based findings. Methods In this retrospective study, all individuals, who had a lumbar spine CT scan and MRI between 2006 and 2012 were reviewed (n = 198). Disc height (DH) and endplate degeneration (ED) were evaluated between Th12/L1-L5/S1. Statistics consisted of Spearman correlation and univariate/multivariable regression (adjusting for age and gender). Results The mean CT-DH increased kranio-caudally (8.04 millimeters (mm) at T12/L1, 9.17 mm at L1/2, 10.59 mm at L2/3, 11.34 mm at L3/4, 11.42 mm at L4/5 and 10.47 mm at L5/S1). MRI-ED was observed in 58 (29%) individuals. CT-DH and MRI-DH had strong to very strong correlations (rho 0.781-0.904, p

Purpose: This study investigated potential use of computed tomography (CT)-based parameters in the lumbar spine as a surrogate for magnetic resonance imaging (MRI)-based findings. Methods: In this retrospective study, all individuals, who had a lumbar spine CT scan and MRI between 2006 and 2012 were reviewed (n = 198). Disc height (DH) and endplate degeneration (ED) were evaluated between Th12/L1-L5/S1. Statistics consisted of Spearman correlation and univariate/multivariable regression (adjusting for age and gender). Results: The mean CT-DH increased kranio-caudally (8.04 millimeters (mm) at T12/L1, 9.17 mm at L1/2, 10.59 mm at L2/3, 11.34 mm at L3/4, 11.42 mm at L4/5 and 10.47 mm at L5/S1). MRI-ED was observed in 58 (29%) individuals. CT-DH and MRI-DH had strong to very strong correlations (rho 0.781-0.904, p <.001). MRI-DH showed higher absolute values than CT-DH (mean of 1.76 mm). There was a significant association between CT-DH and MRI-ED at L2/3 (p =.006), L3/4 (p =.002), L4/5 (p <.001) and L5/S1 (p <.001). A calculated cut-off point was set at 11 mm. Conclusions: In the lumbar spine, there is a correlation between disc height on CT and MRI. This can be useful in trauma and emergency cases, where CT is readily available in the lack of an MRI. In addition, in the middle and lower part of the lumbar spine, loss of disc height on CT scans is associated with more pronounced endplate degeneration on MRIs. If the disc height on CT scans is lower than 11 mm, endplate degeneration on MRIs is likely more pronounced. Level and design: Level III, a retrospective study. [ABSTRACT FROM AUTHOR]

Lumbar disc herniation (LDH) results in low back pain due to nerve root compression caused by nucleus pulposus degeneration. Chemonucleolysis of the nucleus pulposus by injection of condoliase is less invasive than surgery, but may cause disc degeneration. The purpose of the study was to examine outcomes of condoliase injection in patients in their teens and twenties using Pfirrmann criteria on MRI. A single-center retrospective study was performed in 26 consecutive patients (19 men, 7 women) who underwent condoliase injection (1 mL, 1.25 U/mL) for LDH and had MRI scans at 3 and 6 months. Cases with and without an increase in Pfirrmann grade at 3 months post-injection were included in groups D (disc degeneration, n = 16) and N (no degeneration, n = 10). Pain was measured on a visual analogue scale (VAS). MRI findings were evaluated using the % change in disc height index (ΔDHI). The mean age of the patients was 21.1 ± 4.1 years and 12 were <20 years old. At baseline, 4, 21 and 1 were in Pfirrmann grades II, III and IV. In group D, no case had a further increase in Pfirrmann grade from 3 to 6 months. Pain significantly decreased in both groups. There were no adverse events. MRI showed a significant decrease in ΔDHI from 100% pre-injection to 89.4 ± 9.7% at 3 months in all cases (p < 0.05). There was a significant recovery in ΔDHI in group D from 3 to 6 months (85.4 ± 9.3% vs. 86.7 ± 9.1%, p < 0.05). These results suggest that chemonucleolysis with condoliase is effective and safe for LDH in young patients. Progression of Pfirrmann criteria at 3 months post-injection occurred in 61.5% of cases, but disc degeneration showed recovery in these patients. A longer-term study of the clinical symptoms related to these changes is required. [ABSTRACT FROM AUTHOR]

Mechanical testing is a valuable tool for assessing intervertebral disc health, but the wide range of testing protocols makes it difficult to compare results from different studies. Normalizing mechanical properties by disc geometry allows for such comparisons, but there is little consistency in the methods by which disc geometry is measured. As such, we hypothesized that methods used to measure disc geometry would impact reported mechanical properties. Disc height and area were measured using computed tomography (CT), digital calipers, and ImageJ to yield three different measurements for disc height and six for disc area. Disc heights measured by digital calipers ex situ were >30% less than disc heights measured in situ by CT, and disc areas measured ex situ using ImageJ were >30% larger than those measured by CT. This significantly affected reported mechanical properties, leading to a 65% reduction in normalized compressive stiffness in the most extreme case. Though we cannot quantitatively correct between methods, results presented in this study suggest that disc geometry measurement methods have a significant impact on normalized mechanical properties and should be accounted for when comparing results.

Objective Cage subsidence is a common morbidity after oblique lumbar interbody fusion (OLIF), with risk of compromising clinical and radiographic outcomes. The study aims to describe an innovative reverse lumbar pedicle screw (RLPS) technique in OLIF and compare its effect on restricting cage subsidence with classical lateral fixation (LF) in radiological and clinical evaluation. Method Consecutive patients having undergone single‐level OLIF‐LF/RLPS from 2018 to 2020 were retrospectively reviewed. In OLIF‐RLPS, the upper entry point was determined at the intersection between one horizontal line (1 cm above inferior endplate) and one vertical line (dissecting anterior and middle thirds of the vertebra) while the inferior entry point between one horizontal line (5 mm below superior endplate) and the same vertical line. Trajectories were from vertebrae reverse into contralateral pedicle. Radiological evaluation included disc height (DH) and segmental lordosis (SL); cage subsidence was evaluated by DH loss. Clinical assessment included visual analogue scale (VAS) and Oswestry disability index (ODI). Student t or Mann–Whitney U test was used for continuous variation according to normality analysis while Chi‐square test for category variation. Results A total of 29 patients had been enrolled in the study including 14 cases in the RLPS group and 15 cases in the LF group. The DH in the OLIF‐RLPS group had increased from the preoperative 9.07 ± 1.73 mm to 13.73 ± 1.83 mm postoperatively, without significant difference compared with the OLIF‐LF group during the perioperative, but decreased to 12.53 ± 1.74 mm in 3 months and maintained at 12.00 ± 1.45 mm in 12 months, significantly higher than the OLIF‐LF group (p

Biomaterials, such as hydrogels, have an increasingly important role in the development of regenerative approaches for the intervertebral disc. Since animal models usually resist biomaterial injection due to high intradiscal pressure, preclinical testing of the biomechanical performance of biomaterials after implantation remains difficult. Papain reduces the intradiscal pressure, creates cavities within the disc, and allows for biomaterial injections. But papain digestion needs time, and cadaver experiments that are limited to 24 h for measuring range of motion (ROM) cannot not be combined with papain digestion just yet. In this study, we successfully demonstrate a new organ culture approach, facilitating papain digestion to create cavities in the disc and the testing of ROM, neutral zone (NZ), and disc height. Papain treatment increased the ROM by up to 109.5%, extended NZ by up to 210.9%, and decreased disc height by 1.96 ± 0.74 mm. A median volume of 0.73 mL hydrogel could be injected after papain treatment, and histology revealed a strong loss of proteoglycans in the remaining nucleus tissue. Papain has the same biomechanical effects as known from nucleotomies or herniations and thus creates a disc model to study such pathologies in vitro. This new model can now be used to test the performance of biomaterials.

Lumbar disc bulging or herniation (LDBH) is one of the major causes of spinal stenosis and related nerve compression, and its severity is the major determinant for spine surgery. MRI of the spine is the most important diagnostic tool for evaluating the need for surgical intervention in patients with LDBH. However, MRI utilization is limited by its low accessibility. Spinal X-rays can rapidly provide information on the bony structure of the patient. Our study aimed to identify the factors associated with LDBH, including disc height, and establish a clinical diagnostic tool to support its diagnosis based on lumbar X-ray findings. In this study, a total of 458 patients were used for analysis and 13 clinical and imaging variables were collected. Five machine-learning (ML) methods, including LASSO regression, MARS, decision tree, random forest, and extreme gradient boosting, were applied and integrated to identify important variables for predicting LDBH from lumbar spine X-rays. The results showed L4-5 posterior disc height, age, and L1-2 anterior disc height to be the top predictors, and a decision tree algorithm was constructed to support clinical decision-making. Our study highlights the potential of ML-based decision tools for surgeons and emphasizes the importance of L1-2 disc height in relation to LDBH. Future research will expand on these findings to develop a more comprehensive decision-supporting model. [ABSTRACT FROM AUTHOR]

BACKGROUND: It is known that a possible decrease in disc height (DH) and foraminal size after open lumbar microdiscectomy (OLM) may cause pain in the long term. However, there is still insufficient information about the short- or long-term pathoanatomical and morphological effects of microdiscectomy. For example, the exact temporal course of the change in DH is not well known. OBJECTIVE: The purpose of this study was to examine morphological changes in DH and foramen dimensions after OLM. METHODS: In patients who underwent OLM for single-level lumbar disc herniation, MRI scans were obtained before surgery, and at an average of two years after surgery. In addition to DH measurements, foraminal area (FA), foraminal height (FH), superior foraminal width (SFW), and inferior foraminal width (IFW), were measured bilaterally. RESULTS: A postoperative increase in DH was observed at all vertebral levels, with an average of 5.5%. The mean right FHs were 15.3 mm and 15.7 mm before and after surgery, respectively (p = 0.062), while the left FHs were 14.8 mm and 15.8 mm before and after surgery (p = 0.271). The mean right SFW was 5.4 mm before surgery and 5.7 mm after surgery, while the mean right IFW ranged from 3.6 mm to 3.9 mm. The mean left SFW was 4.8 mm before surgery and 5.2 mm after surgery, while the mean left IFW ranged from 3.5 mm to 3.9 mm. Before surgery, the FAs were, on average, 77.1 mm 2 and 75.6 mm 2 on the right and left sides, respectively. At the 2-year follow-up, the mean FAs were 84.0 mm 2 and 80.2 mm 2 on the right and left sides, respectively. CONCLUSIONS: Contrary to prevalent belief, in patients who underwent single-level unilateral OLM, we observed that there may be an increase rather than a decrease in DH or foramen size at the 2-year follow-up. Our findings need to be confirmed by studies with larger sample sizes and longer follow-ups. [ABSTRACT FROM AUTHOR]

Objective: Cage subsidence is a common morbidity after oblique lumbar interbody fusion (OLIF), with risk of compromising clinical and radiographic outcomes. The study aims to describe an innovative reverse lumbar pedicle screw (RLPS) technique in OLIF and compare its effect on restricting cage subsidence with classical lateral fixation (LF) in radiological and clinical evaluation. Method: Consecutive patients having undergone single‐level OLIF‐LF/RLPS from 2018 to 2020 were retrospectively reviewed. In OLIF‐RLPS, the upper entry point was determined at the intersection between one horizontal line (1 cm above inferior endplate) and one vertical line (dissecting anterior and middle thirds of the vertebra) while the inferior entry point between one horizontal line (5 mm below superior endplate) and the same vertical line. Trajectories were from vertebrae reverse into contralateral pedicle. Radiological evaluation included disc height (DH) and segmental lordosis (SL); cage subsidence was evaluated by DH loss. Clinical assessment included visual analogue scale (VAS) and Oswestry disability index (ODI). Student t or Mann–Whitney U test was used for continuous variation according to normality analysis while Chi‐square test for category variation. Results: A total of 29 patients had been enrolled in the study including 14 cases in the RLPS group and 15 cases in the LF group. The DH in the OLIF‐RLPS group had increased from the preoperative 9.07 ± 1.73 mm to 13.73 ± 1.83 mm postoperatively, without significant difference compared with the OLIF‐LF group during the perioperative, but decreased to 12.53 ± 1.74 mm in 3 months and maintained at 12.00 ± 1.45 mm in 12 months, significantly higher than the OLIF‐LF group (p < 0.05). At the last follow‐up, 7.1% (1/14) cases in the OLIF‐RLPS group had shown subsidence of grade I, significantly less than 46.7% (7/15) cases in the OLIF‐LF group. Pain and disability had improved similarly in two groups, without significant difference detected between two groups at the last follow‐up. Conclusion: RLPS technique with modified entry points and prolonged trajectory could effectively restrict cage subsidence in OLIF postoperatively compared with traditional lateral fixation. [ABSTRACT FROM AUTHOR]

Abstract Purpose The purpose of the study was to evaluate the efficacy of OLIF combined with pedicle screw internal fixation in the treatment of lumbar spinal stenosis by assessing the changes in spinal canal before and after surgery. Methods In this retrospective study, we included sixteen patients who underwent a combination of single-segment OLIF and pedicle screw internal fixation for the treatment of lumbar spinal stenosis at the Affiliated Hospital of Jiangxi University of Chinese Medicine between February 2018 and August 2022. The patients' pre- and post-operative data were compared. Intraoperative bleeding, duration of surgery, visual analogue score (VAS), Oswestry Disability Index (ODI), disc height (DH), cross-sectional area of vertebral canal (CSAVC), cross-sectional area of dural sac (CSADS), cross-sectional area of intervertebral foramen (CSAIF), spinal canal volume (SCV), spinal canal volume expansion rate, lumbar lordosis, and sagittal vertical axis were observed and recorded. The efficacy of OLIF combined with pedicle screw internal fixation for lumbar spinal stenosis on spinal canal changes before and after surgery was summarized. Results The results showed that OLIF combined with pedicle screw internal fixation effectively restored disc height and increased the cross-sectional area of the spinal canal. It also had an indirect decompression effect. The intraoperative bleeding and duration of surgery were within acceptable ranges. The VAS and ODI scores significantly improved after surgery, indicating a reduction in pain and improvement in functional disability. The CSAVC, CSADS, CSAIF, SCV, and spinal canal volume expansion rate were all increased postoperatively. Additionally, there was improvement in lumbar lordosis and sagittal vertical axis. We conducted a follow-up of all patients at 1 year after the surgery. The results revealed that the parameter values at 1 year post-surgery showed varying degrees of decrease or increase compared to the immediate postoperative values. However, these values remained statistically significant when compared to the preoperative parameter values (P

Purpose: The purpose of the study was to evaluate the efficacy of OLIF combined with pedicle screw internal fixation in the treatment of lumbar spinal stenosis by assessing the changes in spinal canal before and after surgery. Methods: In this retrospective study, we included sixteen patients who underwent a combination of single-segment OLIF and pedicle screw internal fixation for the treatment of lumbar spinal stenosis at the Affiliated Hospital of Jiangxi University of Chinese Medicine between February 2018 and August 2022. The patients' pre- and post-operative data were compared. Intraoperative bleeding, duration of surgery, visual analogue score (VAS), Oswestry Disability Index (ODI), disc height (DH), cross-sectional area of vertebral canal (CSAVC), cross-sectional area of dural sac (CSADS), cross-sectional area of intervertebral foramen (CSAIF), spinal canal volume (SCV), spinal canal volume expansion rate, lumbar lordosis, and sagittal vertical axis were observed and recorded. The efficacy of OLIF combined with pedicle screw internal fixation for lumbar spinal stenosis on spinal canal changes before and after surgery was summarized. Results: The results showed that OLIF combined with pedicle screw internal fixation effectively restored disc height and increased the cross-sectional area of the spinal canal. It also had an indirect decompression effect. The intraoperative bleeding and duration of surgery were within acceptable ranges. The VAS and ODI scores significantly improved after surgery, indicating a reduction in pain and improvement in functional disability. The CSAVC, CSADS, CSAIF, SCV, and spinal canal volume expansion rate were all increased postoperatively. Additionally, there was improvement in lumbar lordosis and sagittal vertical axis. We conducted a follow-up of all patients at 1 year after the surgery. The results revealed that the parameter values at 1 year post-surgery showed varying degrees of decrease or increase compared to the immediate postoperative values. However, these values remained statistically significant when compared to the preoperative parameter values (P < 0.05). Conclusions: OLIF combined with pedicle screw internal fixation effectively restores disc height and increases the cross-sectional area of the vertebral canal in patients with LSS, reflecting the indirect decompression effect. Measuring parameters such as DH, CSAVC, CSADS, CSAIF, SCV, and SCV expansion rate before and after surgery provides valuable information for evaluating the efficacy and functional recovery of the lumbar spine in LSS patients treated with OLIF surgery. [ABSTRACT FROM AUTHOR]

Background: Lumbar disc degeneration (DD) is widely regarded as a likely contributor to low back pain (LBP), but the association between DD and LBP is relatively weak. No known studies have normalized quantitative measures of DD severity relative to multiple variables such as age, height, and disc level. This study developed normalized quantitative measures (z‐scores) of disc signal intensity (DSI) and disc height (DH) to rate relative severity of DD. Methods: Raw (unnormalized) quantitative measures of DSI and DH alongside potential normalization variables were acquired from MRI scans and clinical data of 76 patients. The associations between the raw quantitative measures and potential normalization variables were investigated to develop the normalized quantitative measures (z‐scores) of DSI and DH. Construct validity was assessed by comparing the normalized measures to an experienced radiologist's subjective measures of relative severity of DSI and DH loss. Results: CSF signal intensity, age, and disc level were significantly associated with raw DSI (R2 = 0.06, 0.25, and 0.09, respectively). Lumbar height and disc level were significantly associated with raw DH (R2 = 0.13 and 0.31). Normalizing DSI and DH by these variables resulted in stronger relationships (R2 = 0.39 and 0.37) than raw DSI and DH (R2 = 0.24 and 0.31) with the radiologist's subjective measures. Normalized DSI and DH were both normally distributed (p = 0.32 and 0.12). Conclusions: Construct validity and the distributions suggested that normalized quantitative measures of DSI and DH are better than existing measures of DSI and DH at rating relative DD severity. Determining whether normalized quantitative measures are more predictive of clinical outcomes is important future research. [ABSTRACT FROM AUTHOR]

Background: Disc height (DH) change is considered one of the most critical factors in assessing intervertebral disc degeneration (IVD). Pfirrmann et al. developed a scoring system for disc degeneration evaluation based on changes in DH in magnetic resonance imaging (MRI). While the relationship between DH measurements and Pfirrmann scores for disc degeneration has been explored, the validity of different DH measuring techniques or their connection with disc degeneration is yet uncertain. The present study investigates intra-rater and inter-rater agreement and reliability of different DH measurement methods on MRI and evaluates the relationship between different DH measurement methods and Pfirrmann scores of IVD degeneration, as well as between different Pfirrmann scores and clinical outcomes. Methods: Adult patients with MRI scans of the lumbar spine were recruited. Eight DH measuring techniques were tested for intra-rater and inter-rater agreement and reliability. Bland and Altman's Limits of Agreement (LOA) was used to evaluate intra-rater and inter-rater agreements. Intra-rater and inter-rater reliability were evaluated using intra-class correlations (ICC) with 95 % confidence intervals (95 % CI). The association between DH and Pfirrmann scores was examined using one-way ANOVA. Results: Excellent intra-rater reliability was reported for 332 participants on DH (ranging from 0.912 (0.901, 0.923) to 0.973 (0.964, 0.981) and from 0.902 (0.892, 0.915) to 0.975 (0.962, 0.985) by two independent raters). All measuring methods had high intra-rater agreement, except for methods 4 and 5. All methods had good-to-excellent of inter-rater reliability on DH (ICCs ranging from 0.812 (0.795, 0.828) to 0.995 (0.994, 0.995)) except for the posterior disc material length of method 5 (ICC 0.740 (0.718, 0.761)). Methods 1 to 6 for evaluating DH in patients with spondylolisthesis had poor inter-rater reliability. The IVD levels with grades IV and V in Pfirrmann scores had significantly lower DH than the IVD levels with grades I to III in Pfirrmann scores. IVD levels with grades IV and V in Pfirrmann scores had significantly higher VAS and ODI than IVD levels with grades I in Pfirrmann scores. Conclusion: A good-to-excellent intra-rater and inter-rater reliability was achieved on most DH measuring methods on MRI following a standardized and structured protocol. However, small anatomical structures and different tissue borders could influence measurements. Additionally, DH can differentiate between grade IV and V Pfirrmann scores, and severe IVD degeneration (IV and V Pfirrmann) is linked to clinical outcomes.

Abstract Background Lumbar disc degeneration (DD) is widely regarded as a likely contributor to low back pain (LBP), but the association between DD and LBP is relatively weak. No known studies have normalized quantitative measures of DD severity relative to multiple variables such as age, height, and disc level. This study developed normalized quantitative measures (z‐scores) of disc signal intensity (DSI) and disc height (DH) to rate relative severity of DD. Methods Raw (unnormalized) quantitative measures of DSI and DH alongside potential normalization variables were acquired from MRI scans and clinical data of 76 patients. The associations between the raw quantitative measures and potential normalization variables were investigated to develop the normalized quantitative measures (z‐scores) of DSI and DH. Construct validity was assessed by comparing the normalized measures to an experienced radiologist's subjective measures of relative severity of DSI and DH loss. Results CSF signal intensity, age, and disc level were significantly associated with raw DSI (R2 = 0.06, 0.25, and 0.09, respectively). Lumbar height and disc level were significantly associated with raw DH (R2 = 0.13 and 0.31). Normalizing DSI and DH by these variables resulted in stronger relationships (R2 = 0.39 and 0.37) than raw DSI and DH (R2 = 0.24 and 0.31) with the radiologist's subjective measures. Normalized DSI and DH were both normally distributed (p = 0.32 and 0.12). Conclusions Construct validity and the distributions suggested that normalized quantitative measures of DSI and DH are better than existing measures of DSI and DH at rating relative DD severity. Determining whether normalized quantitative measures are more predictive of clinical outcomes is important future research.

Abstract Background To perform a comparative assessment of percutaneous transfacet screws (TFS) and percutaneous bilateral pedicle screws (BPS) in oblique lateral interbody fusion (OLIF) for the treatment of single-level degenerative lumbar spine diseases in terms of radiological examinations and clinical outcomes. Methods Sixty-six patients who received single-level OLIF with percutaneous supplementary fixation assisted by the robot for the treatment of degenerative lumbar spine diseases were selected. There were 16 cases of OLIF with TFS and 50 cases of OLIF with BPS. The propensity score matching method selected 11 patients in each group with matched characteristics to perform a clinical comparison. Results The estimated blood loss was 68.2 ± 25.2 ml in the OLIF with TFS group compared to 113.6 ± 39.3 ml in the OLIF with BPS group (P 0.05). Quantitative assessments of back/leg pain of the two groups reached a healthy level in the late period of the follow-up. Conclusion Both TFS and BPS techniques for the OLIF surgery relieve back pain caused by degenerative lumbar spine diseases. The TFS technique exhibits less blood loss compared with the BPS. A moderate cage subsidence is present in TFS but no complication is reported.

Intervertebral discs act as shock absorbers, thereby helping to reduce the risk of vertebral body fractures. Previous studies have shown that estrogen loss following menopause is associated with disc height reduction whereas treatment with hormone replacement therapy (HRT) helps to maintain disc height. This study reports the effect of HRT on disc height from a post hoc analysis of a prospective randomized clinical trial of the effect of HRT on bone density. A total of 355 healthy postmenopausal women aged (mean ± standard deviation) 55.4 ± 4.8 years were randomized to HRT with oral 1 mg or 2 mg estradiol plus dydrogesterone or placebo. Dual-energy X-ray absorptiometry measurements (Lunar DPX) were obtained at baseline and following 2 years of treatment. Intervertebral disc height was measured in discs between T12 and L3 using the bone densitometer ruler. Compared with baseline, treatment with HRT resulted in a significant increase in total disc height with 1 mg estradiol (0.16 ± 0.65 cm, p = 0.015) and with 2 mg estradiol (0.21 ± 0.86 cm, p = 0.006) whilst there was no significant increase with placebo (0.13 ± 0.65 cm, p = 0.096). Between-group differences were not statistically significant. These results are consistent with previous findings of a beneficial effect of estrogen on discs. This may be in part responsible for the anti-fracture efficacy of HRT on vertebral fractures. [ABSTRACT FROM AUTHOR]

Purpose: Aging is a risk factor for several debilitating conditions including those related to chronic back pain and intervertebral disc degeneration, both of which have no cure. Mouse models are useful tools for studying disc degeneration and chronic back pain in a tightly controlled and clinically relevant aging environment. Moreover, mice offer the advantage of carrying out longitudinal studies to understand the etiology and progression of disc pathology induced by genetic or surgical strategies. Previously, age-related behavioral trends of discomfort and enhanced nociception in mice were reported; however, whether these measures are mediated by structural and pathological changes in the disc is unknown. Methods: The goal of the present observational study was to identify behavioral correlates of age-related degenerative changes in the disc. Towards this, we collected radiographs from 150 mice (77 females) between three and 23 months of age and measured the disc height index for each level of lumbar disc. Behavioral measures were collected on several of these mice which included rearing and distance travelled in an open field test; time spent in rearing, reaching, immobile, and self-suspended in the tail suspension test; bilateral hind paw licking in response to cold allodynia using acetone; and unilateral hind paw licking in response to heat hyperalgesia using capsaicin. Results: Results show that the lower lumbar discs lose height with age and these changes are independent of body composition measures including body weight, bone mineral density, fat mass, lean weight mass, percent fat mass, and percent lean mass. Disc height positively correlates with rearing and mobility in the open field test, immobility in the tail suspension test, and thermal hyperalgesia. Disc height negatively correlates with cold allodynia and rearing in the tail suspension test. Furthermore, mediation analysis shows that the lumbosacral disc significantly mediates the effect of age on rearing in the open field test, but not cold allodynia, suggesting this behavior is a useful measure of age-related axial discomfort due to disc degeneration. Conclusion: In summary, the findings from the current study show that disc height are associated with measures of axial discomfort and nociception in mice. [ABSTRACT FROM AUTHOR]

Lumbar disc bulging or herniation (LDBH) is one of the major causes of spinal stenosis and related nerve compression, and its severity is the major determinant for spine surgery. MRI of the spine is the most important diagnostic tool for evaluating the need for surgical intervention in patients with LDBH. However, MRI utilization is limited by its low accessibility. Spinal X-rays can rapidly provide information on the bony structure of the patient. Our study aimed to identify the factors associated with LDBH, including disc height, and establish a clinical diagnostic tool to support its diagnosis based on lumbar X-ray findings. In this study, a total of 458 patients were used for analysis and 13 clinical and imaging variables were collected. Five machine-learning (ML) methods, including LASSO regression, MARS, decision tree, random forest, and extreme gradient boosting, were applied and integrated to identify important variables for predicting LDBH from lumbar spine X-rays. The results showed L4-5 posterior disc height, age, and L1-2 anterior disc height to be the top predictors, and a decision tree algorithm was constructed to support clinical decision-making. Our study highlights the potential of ML-based decision tools for surgeons and emphasizes the importance of L1-2 disc height in relation to LDBH. Future research will expand on these findings to develop a more comprehensive decision-supporting model.

Background: To perform a comparative assessment of percutaneous transfacet screws (TFS) and percutaneous bilateral pedicle screws (BPS) in oblique lateral interbody fusion (OLIF) for the treatment of single-level degenerative lumbar spine diseases in terms of radiological examinations and clinical outcomes. Methods: Sixty-six patients who received single-level OLIF with percutaneous supplementary fixation assisted by the robot for the treatment of degenerative lumbar spine diseases were selected. There were 16 cases of OLIF with TFS and 50 cases of OLIF with BPS. The propensity score matching method selected 11 patients in each group with matched characteristics to perform a clinical comparison. Results: The estimated blood loss was 68.2 ± 25.2 ml in the OLIF with TFS group compared to 113.6 ± 39.3 ml in the OLIF with BPS group (P < 0.05). The intervertebral disc height raised from 8.6 to 12.9 mm in the TFS group and from 8.9 to 13.9 mm in the BPS group in the immediate postoperative period, and dropped to 10.8 and 12.9 mm at the twelfth month, respectively (P < 0.05). The fusion rates were 91% and 100% for TFS and BPS groups (P > 0.05). Quantitative assessments of back/leg pain of the two groups reached a healthy level in the late period of the follow-up. Conclusion: Both TFS and BPS techniques for the OLIF surgery relieve back pain caused by degenerative lumbar spine diseases. The TFS technique exhibits less blood loss compared with the BPS. A moderate cage subsidence is present in TFS but no complication is reported. [ABSTRACT FROM AUTHOR]

Objective To investigate whether the radiographic results are affected by cage position in single‐level transforaminal lumbar interbody fusion (TLIF). Method Between January 2016 and June 2018, 130 patients (62 males and 68 females, average age: 55.28 ± 10.11 years) who underwent single‐level TLIF were analyzed retrospectively. Standing lateral radiographs of the lumbar spine were collected and evaluated preoperatively, postoperatively, and at the time of last follow‐up. Cage position in the fused segment was recorded using a central point ratio (CPR), which indicated the cage position. CPR is calculated by dividing the distance between the cage center point and the posterior extent of the superior endplate of the inferior vertebra by the length of the superior endplate of the inferior vertebra. Based on cage positions, the patients were divided into three groups: Anterior Group (n = 38); Middle Group (n = 68); and Posterior Group (n = 24). Segmental lumbar lordosis (SLL), foraminal height (FH), posterior disc height (PDH), and anterior disc height (ADH) were evaluated. A subanalysis was also performed on cage height within each group. Results The average follow‐up time of the patients was 35.20 ± 4.43 months. The mean values of CPR in Anterior Group, Middle Group, and Posterior Group were 0.64, 0.51, and 0.37, respectively. The FH, PDH, and ADH were significantly increased after TLIF in all groups (P 0.05). The significant correlations in surgery were: CPR and ΔSLL (r = 0.584, P

Due to the lack of an additional anterior plate, the motion stability of a zero-profile device with an anchored cage (AC) may be inferior to that of a traditional plate-cage construct (PCC). However, the impact of this difference in motion stability on various outcomes has not been fully explored. Therefore, the aim of this study was to compare the motion stabilization features of an AC and a PCC and analyze their impact on postoperative outcomes and complications. A retrospective study of patients treated with single-level anterior cervical discectomy and fusion from January 2008 to May 2016 was performed. First, clinical and radiological outcomes, postoperative complications and time to achieve motion stabilization were compared between the AC and PCC groups. Then, based on the time to achieve motion stabilization, all patients were divided into group A (time to achieve motion stabilization <3 months), group B (time to achieve motion stabilization from 3–6 months), and group C (time to achieve motion stabilization >6 months). The early postoperative complications were compared across the 3 groups. Motion stabilization was measured on dynamic cervical radiographs using the interspinous process method and Cobb angle method according to previously published methods. A total of 160 patients met the inclusion criteria, including 90 patients in the AC group and 70 patients in the PCC group. There were no significant differences between the AC and PCC groups in the clinical outcomes, C2–7 angle change, segmental angle change, final fusion rate or adjacent-level degeneration (P > 0.05). The disc height loss was 2.26 ± 1.00 mm in the AC group and 1.76 ± 1.13 mm in the PCC group (P = 0.004), and the incidence of implant subsidence was 24.44% in the AC group and 11.43% in the PCC group (P = 0.036). In addition, the PCC was more dynamically stable than the AC at 3 months post-surgery (P < 0.001), and at this time, the disc height loss and implant subsidence in motion-stable patients were significantly lower than those in motion-unstable patients (P < 0.05). Furthermore, our results also showed that when the arrival time of motion stabilization was prolonged, the loss of disc height and occurrence of subsidence gradually increased. More attention should be given to minimizing the adverse impact of poor motion stability in the design and development of future zero-profile cervical implants, although this has little impact on clinical efficacy. [ABSTRACT FROM AUTHOR]

• Systematic training and structured protocol are required to conduct measurement. • Complicated methods and intervertebral disc degeneration affected the inter-rater agreement on measurements. • Method 7 is the best reproducible method to measure disc height index for all intervertebral disc segmental levels with a good-to-excellent intra- and inter-rater reliability and agreement. To evaluate intra- and inter-rater agreement and reliability of seven reported disc height index (DHI) measurement methods on standing lateral X-ray of lumbar spine. The adult patients who had standing lateral X-ray of lumbar spine were recruited. Seven methods were used to measure DHI of each lumbar intervertebral disc level, including a ratio of sum of anterior and posterior disc height (DH) to disc diameter (Method 1), a ratio of middle DH to mid-vertebral body height (Method 2), a ratio of middle DH to disc diameter (Method 3), a ratio of the mean of anterior, middle, and posterior DH to the sagittal diameter of the proximal vertebral body (Method 4), a ratio of DH to vertebral height which cross the centre of adjacent vertebral bodies (Method 5), a ratio of the mean of anterior, middle, and posterior DH to the mean of proximal and distal vertebral body height (Method 6), and a ratio of the sum of anterior and posterior DH to the sum of superior and inferior disc depth (Method 7). Two raters conducted the measurements (one medical student (SS) and the other an experienced spine surgeon (XC)). Bland and Altmańs Limits of Agreement (LOA) with standard difference were calculated to examine intra- and inter-rater agreements between two out of seven methods for DHI. Intra-class correlations (ICC) with 95% confidence intervals were calculated to assess intra- and inter-rater reliability. The intra-rater reliability in DHI measurements for 288 participants were ICCs from 0.807 (0.794, 0.812) to 0.922 (0.913, 0.946) by rater 1 (SS) and from 0.827 (0.802, 0.841) to 0.918 (0.806, 0.823) by rater 2 (XC). Method 2, 3, and 5 on all segmental levels had bias (95 % CI does not include zero) or/and out of the acceptable cut-off proportion (>50 %). A total of 609 outliers in 9174 segmental levels' LOA range. Inter-rater reliability was good-to-excellent in all but method 2 (0.736 (0.712, 0.759)) and method 5 (0.634 (0.598, 0.667)). ICCs of related lines to good-to-excellent reliability methods was excellent in all but only indirect lines in method 1 and 4 (ICCs lie in the range from 0.8 to 0.9). Following a structured protocol, intra- and inter-rater reliability was good-to-excellent for most DHI measurement methods on X-ray. However, the complicated methods (more indirect lines) and IVD degeneration (nucleus pulposus degeneration and disc herniation) potentially affected the agreement on inter-rater measurements. Method 7 is the best reproducible method to measure disc height index for all intervertebral disc segmental levels with a good-to-excellent intra- and inter-rater reliability and agreement. [ABSTRACT FROM AUTHOR]

Background: 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., Methods: 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., Results: 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., Conclusion: 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., (Copyright © 2024. Published by Elsevier Inc.)

Background Context: Expandable transforaminal lumbar interbody fusion (TLIF) cages have become popular in recent years due to anticipated advantages of increased disc height, improved segmental lordosis, and ease of implantation. Such benefits have not been conclusively demonstrated in the literature., Purpose: To determine whether expandable cages increase disc height and segmental lordosis in a durable way following surgery and compare complication profiles between cage types., Study Design/setting: Retrospective cohort study conducted within a large academic health system involving 31 different spine surgeons., Patient Sample: Adults undergoing single-level TLIF for an indication other than infection, tumor, trauma, or revision instrumentation from 2021 to 2023., Outcome Measures: Our primary outcomes were changes in segmental disc height, segmental lordosis, and L4-S1 lordosis at 2 weeks, 6 months, and 1 year following surgery relative to baseline. Our secondary outcomes were frequencies of incidental durotomies, surgical site infections, readmissions, death, subsidence, and unplanned return to the operating room., Methods: Radiographic variables were collected from our institutional imaging registry. Demographics and surgical characteristics were abstracted from chart review. Generalized linear modeling was used for each primary outcome, with cage type (expandable vs. static) as our primary predictor and age, biologic sex, race, CCI, year of surgery, duration of surgery, invasiveness of surgery, surgeon specialty (Orthopedics vs. Neurosurgery), and level of surgery as covariates., Results: Our cohort consisted of 417 patients with a mean age of 62. Static cages were used in 306 patients and expandable cages in 111. Expandable cages were associated with increased changes in disc height relative to static cages at 2 weeks (1.1 mm [0.2-1.9]; p=.01) and 6 months (1.2 mm [0.2-2.3]; p=.02) following surgery, but differences were no longer significant at 1 year (0.4 mm [-0.9-1.8]; p=.4). Expandable cages were found to subside more commonly than static cages (14.1% vs. 6.6%; p=.04). No significant differences between cage types were identified in lordotic parameters at any timepoint (p=0.25 to p=0.97)., Conclusions: Expandable cages were associated with an initial increase in disc height relative to static cages, but this difference diminished with the first year of surgery, likely due to a higher rate of subsidence within the expandable cohort., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Inc. All rights reserved.)

ObjectiveTo evaluate the radiologic parameters of degenerative lumbar spondylolisthesis (DLS) and determine the radiographic risk factors for DLS by making comparisons with healthy control subjects.MethodsSeventy-five patients with L4/5 DLS (Meyerding grade I) and 53 healthy control subjects were analyzed. The L1-S1 disc height index (DHI), L4/5 facet joint angle (FJA), and relative cross-sectional area (RCSA) of paravertebral muscles were measured in both groups. The initial L4/5 DHI (iDHI) before the onset of DLS were estimated based on the L3/4 DHI of the DLS group and DHI of the control group. The sagittal parameters of DLS were also included in this study.ResultsThe DHI of L4/5 was lower in the DLS group than in the control group (P

Abstract Mechanical testing is a valuable tool for assessing intervertebral disc health, but the wide range of testing protocols makes it difficult to compare results from different studies. Normalizing mechanical properties by disc geometry allows for such comparisons, but there is little consistency in the methods by which disc geometry is measured. As such, we hypothesized that methods used to measure disc geometry would impact reported mechanical properties. Disc height and area were measured using computed tomography (CT), digital calipers, and ImageJ to yield three different measurements for disc height and six for disc area. Disc heights measured by digital calipers ex situ were >30% less than disc heights measured in situ by CT, and disc areas measured ex situ using ImageJ were >30% larger than those measured by CT. This significantly affected reported mechanical properties, leading to a 65% reduction in normalized compressive stiffness in the most extreme case. Though we cannot quantitatively correct between methods, results presented in this study suggest that disc geometry measurement methods have a significant impact on normalized mechanical properties and should be accounted for when comparing results.

BACKGROUND: Low frequency vibrations from motorized vehicles and heavy equipment have been associated with musculoskeletal disorders. Spine degeneration on diagnostic imaging provides direct and objective measures of the possible effects of such exposures on the spine. OBJECTIVE: The objective of this systematic review was to evaluate the association of exposure to whole-body vibration (WBV) with spine degeneration on imaging. METHODS: We conducted electronic searches in MEDLINE, CINAHL, EMBASE, and Web of Science to July 2021. Two reviewers independently screened search results, assessed quality, and extracted data. Studies evaluating the exposure to WBV and lumbar spine degeneration on imaging were included. RESULTS: Fifteen studies (16 manuscripts) were included. Seven studies including a meta-demonstrated moderate quality evidence of no association between WBV and disc degeneration. There was also moderate quality evidence of no association between WBV and disc height narrowing and osteophytes. Overall, there was low level evidence of no association between WBV and other degenerations findings. CONCLUSIONS: There was moderate to low quality evidence suggesting no association between WBV exposures with spine degeneration on imaging. The results of this study currently do not support assertion that motorized vehicle and WBV exposure accelerates degeneration and causes structural damage to the spine. [ABSTRACT FROM AUTHOR]

Background: In the regeneration and therapy of degenerated intervertebral discs, the height, volume or categorizing assessments, such as Pfirrmann classification, are used to quantify the discs themselves and the effects of therapy. Here, the question of transferability, in the sense of reliability, of the results arises in the common exchange. Methods: We have investigated two established and a newly developed (9-point measurement), easy to use methods for height measurement and volume measurement on degenerated and healthy lumbar intervertebral discs of 66 patients regarding inter- and intra-observer reliability. Results: In overview, we found very different reliabilities. While the intra-observer reliability showed good to excellent agreement for both healthy and degenerated lumbar discs for the height and volume measurements, the inter-observer reliability was low or moderate in some cases. The 9-point method for height determination consistently showed better reliability for both healthy and degenerated discs, for both intra- and inter-observer reliability, compared to the two established methods. Conclusions: We recommend using the 9-point measurement as the method to communicate lumbar disc height, both for healthy and degenerated discs. Due to the partly low or moderate reliability, significant differences in the measured heights can already occur, which can lead to a worsened comparability. [ABSTRACT FROM AUTHOR]

Objective: To investigate whether the radiographic results are affected by cage position in single‐level transforaminal lumbar interbody fusion (TLIF). Method: Between January 2016 and June 2018, 130 patients (62 males and 68 females, average age: 55.28 ± 10.11 years) who underwent single‐level TLIF were analyzed retrospectively. Standing lateral radiographs of the lumbar spine were collected and evaluated preoperatively, postoperatively, and at the time of last follow‐up. Cage position in the fused segment was recorded using a central point ratio (CPR), which indicated the cage position. CPR is calculated by dividing the distance between the cage center point and the posterior extent of the superior endplate of the inferior vertebra by the length of the superior endplate of the inferior vertebra. Based on cage positions, the patients were divided into three groups: Anterior Group (n = 38); Middle Group (n = 68); and Posterior Group (n = 24). Segmental lumbar lordosis (SLL), foraminal height (FH), posterior disc height (PDH), and anterior disc height (ADH) were evaluated. A subanalysis was also performed on cage height within each group. Results: The average follow‐up time of the patients was 35.20 ± 4.43 months. The mean values of CPR in Anterior Group, Middle Group, and Posterior Group were 0.64, 0.51, and 0.37, respectively. The FH, PDH, and ADH were significantly increased after TLIF in all groups (P < 0.05). There were significant differences in increase of SLL in Anterior Group (4.4°) and Middle Group (3.0°), but not in Posterior Group (0.3°). Furthermore, in the comparison of the three groups, the increase of SLL, FH, and PDH was statistically different (P < 0.05), while not for ADH (P > 0.05). The significant correlations in surgery were: CPR and ΔSLL (r = 0.584, P < 0.001), CPR and ΔFH (r = −0.411, P < 0.001), and CPR and ΔPDH (r = −0.457, P < 0.001). However, ADH had a positive correlation with cage height when the cage was located in anterior and middle of the endplate. Moreover, cage height had a positive correlation with SLL when the cage was located anteriorly and had a negative correlation with SLL when the cage was located posteriorly. FH and PDH both had a positive correlation with cage height in any cage position. Conclusion: The cage located in different positions has different effects on radiographic results in single‐level TLIF. A thicker cage located anteriorly will gain maximum SLL and avoid the reduction of FH and PDH. [ABSTRACT FROM AUTHOR]

Steerable "banana" cages have been posited to increase segmental lordosis in short-segment transforaminal lumbar interbody fusions (TLIF). The same is not necessarily true for straight "bullet" cages. Although increased lordosis is generally thought to be advantageous, a potential complication is decreased foraminal height. Here we evaluate for any association between cage type and change in foraminal height and clinical outcomes following short-segment TLIFs. We retrospectively reviewed consecutive 1- and 2-level TLIFs with bilateral facetectomies with minimum 1-year clinical and radiographic follow-up. Two cohorts were based on cage morphology: steerable "banana" cage or straight "bullet" cage. Patient reported outcome measures (PROMs), radiographic measurements, and revision rates were compared. A total of 46 patients with 53 straight and 95 patients with 131 steerable cage levels were included. Steerable cages showed increased segmental lordosis (9.1° vs. 13.5°, P < 0.001) and decreased foraminal height (20.3 vs. 18.5 mm, P < 0.001) after surgery. Straight cages demonstrated similar segmental lordosis (8.7° vs 8.1°, P = 0.30) and foraminal height (19.4 vs 20.0 mm, P < 0.065). Both cohorts showed improved PROMs at last follow-up (P ≤ 0.005). Subanalysis comparing patients who had increased or decreased foraminal height revealed similarly improved PROMs between cohorts. Revision rates at 1 year were similar between cohorts (4.3% for straight and 3.2% for steerable group, P = 0.72). Although the increased segmental lordosis afforded by placement of steerable cages may decrease foraminal height after short segment TLIF, clinical outcomes are not negatively affected by this association. [ABSTRACT FROM AUTHOR]

Abstract Background Percutaneous 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. Methods A 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. Results Patients treated by PELD had lower blood loss and shorter hospital stay (P

Objective To evaluate a radiological difference between the oblique lumbar interbody fusion (OLIF) L5-S1 and transforaminal lumbar interbody fusion (TLIF) L5-S1 procedure. Methods 16 patients who underwent single-level OLIF L5-S1 and 32 patients of TLIF L5-S1 were retrospectively reviewed. Assessment of the lumbopelvic parameters and the height of disc space and L5-S1 neural foramen was performed before surgery as well as a month after surgery. Results Preoperatively, OLIF L5-S1 group and TLIF group showed similar lumbar lordosis (LL), segmental lordosis (SL), pelvic incidence (PI), pelvic tilt (PT) and sacral slope (SS); (p=0.08, 0.48, 0.67, 0.19 and 0.12, respectively). Postoperatively those parameters did not show statistically significant differences between two groups (p=0.17, 0.32, 0.53, 0.16 and 0.19, respectively). In terms of disc and foraminal height, the OLIF L5-S1 group showed significant greater increase of posterior disc height and foraminal height (p=0.01 and 0.00). There was no significant differences between the two groups in mean VAS and ODI score over the follow-up period. Conclusion This study demonstrates that both OLIF L5-S1 group and TLIF L5-S1 group had similar ability of achieving lumbopelvic alignment however, increase of foraminal height was greater in patients with OLIF L5-S1 group.

Study Design Retrospective case-control study. Purpose We aimed to compare radiologic outcomes between posterior (PLIF) and lateral lumbar interbody fusion (LLIF) in short-level spinal fusion surgeries. Overview of Literature Although LLIF enables surgeons to insert large lordotic cages, it is unknown whether LLIF more effectively corrects local and global sagittal alignments compared with PLIF in short-level spinal fusion surgeries. Methods Radiographic data acquired from patients with lumbar interbody fusion (≤3 levels) using PLIF or LLIF for degenerative lumbar diseases were analyzed. The following radiographic parameters were evaluated preoperatively and at 2 years postoperatively: segmental lordotic angle, disk height, lumbar lordosis (LL), pelvic tilt (PT), C7 sagittal vertical axis, and thoracic kyphosis (TK). Results In total, 144 patients with PLIF (193 fused levels) and 101 with LLIF (159 fused levels) were included. Patients’ backgrounds and preoperative radiographic parameters for any level of fusion did not differ significantly between PLIF and LLIF procedures. The LLIF group exhibited significantly greater changes at 1-level fusion compared to the PLIF group in the parameters of segmental lordotic angle (5.1°±5.8° vs. 2.1°±5.0°, p

Purpose: To evaluate the impact of discectomy on disc height (DH) in lumbar disc herniation (LDH) patients following discectomy surgery and address the association of DH change with pain score change. Methods: We searched three online databases for randomized controlled trials (RCTs) and observational studies. In LDH patients, eligible for discectomy surgery, the changes in pre- and post-operative back and/or leg pain score and DH and/or disc height index (DHI) were considered as primary outcomes. Standardize mean difference (SMD) and their 95% confidence intervals (CI) were evaluated. The GRADE approach was used to summarize the strength of evidence. Results: Two RCTs and sixteen observational studies were included in the analysis of 893 LDH patients undergoing discectomy surgery. The mean overall follow-up was 211 weeks. There was a statistically significant reduction in DH (14.4% reduction: SMD = −0.74 (95% CI = −0.86 to −0.61)) and DHI (11.5% reduction: SMD = −0.81 (95% CI = −0.97 to −0.65)) following discectomy surgery. There was a significant relationship between the reduction in DH and decrease in back pain score (r = 0.68, (95% CI = 0.07–1.30), p = 0.034) after discectomy surgery. No significant relationship between DHI change and decrease in clinical pain scores (back and leg pain) could be established. Conclusion: Discectomy surgery produces significant and quantifiable reductions in DH and DHI. Additionally, the reduction in DH is responsible for the decrease in back pain scores post discectomy, but further studies will improve understanding and aid preoperative counselling. [ABSTRACT FROM AUTHOR]

Mini: Some of the improvements in DH, FH, and SLL achieved intraoperatively during lateral lumbar interbody fusion surgery were lost by the postoperative 1-week follow-up. An intraoperative radiograph can predict radiographic and clinical outcomes of the 2-year follow-up. The difference between preoperative DH and intraoperative DH should be >4.18 mm. [ABSTRACT FROM AUTHOR]

Abstract Background There are inconsistencies in findings regarding the relationship of occupational loading with spinal degeneration or structural damage. Thus, a systematic review was conducted to determine the current state of knowledge on the association of occupational loading and spine degeneration on imaging. Methods We performed electronic searches on MEDLINE, CINAHL and EMBASE. We included cross-sectional, case control and cohort studies evaluating occupational loading as the exposure and lumbar spine structural findings on imaging as the outcomes. When possible, results were pooled. Results Seventeen studies were included in the review. Ten studies evaluated the association of occupational loading with disc degeneration (signal intensity), four of which were pooled into a meta-analysis. Of the 10 studies, only two did not identify a relationship between occupation loading and disc degeneration. A meta-analysis including four of the studies demonstrated an association between higher loading and degeneration for all spinal levels, with odds ratios between 1.6 and 3.3. Seven studies evaluated disc height narrowing and seven evaluate disc bulge, with six and five identifying an association of loading and with imaging findings respectively. Three studies evaluated modic changes and one identified and association with occupational load. Conclusions There was moderate evidence suggesting a modest association between occupational loading and disc degeneration (signal intensity), and low-quality evidence of an association between occupational loading and disc narrowing and bulging.

Abstract Background The aim of this study was to investigate the correlation between radiographic measurement in lumbar spine and clinical information including symptoms or results of functional testing using a baseline data of longitudinal cohort study. Methods A total of 314 elderly subjects were recruited from 5 orthopedic clinics or affiliated facilities. Data for the present investigation were collected via an interviewer-administered questionnaire, which included questions on past medical history, drug history, pain area. And also results of functional testing and X-ray imaging of the lumbar spine were collected. Analysis was carried out to determine any correlation between results of X-ray imaging of the lumbar spine and other collected data, and sorted regarding Akaike Information Criterion (AIC). The correlations among these variables and odds ratio were also analyzed. Results T12/L1% disc height showed a minimum AIC value with buttock pain (− 4.57) and history of vertebral fracture (− 4.05). The L1/L2, L2/L3, and L3/L4% disc height had a minimal AIC value with knee pain (− 4.11, − 13.3, − 3.15, respectively), and odds ratio of knee pain were 3.5, 3.8, and 2.7, respectively. Conclusions Correlation was recognized between the T12/L1% disc height and both buttock pain and previous vertebral fractures, and the L1/L2, L2/L3, and L3/L4% disc height showed a correlation with knee pain. Especially the L2/L3% disc height and knee pain had a strong correlation. It was suggested that these findings may provide additional basis to the concept that lumbar spinal lesion associates with knee pain clinically.

Background: In the regeneration and therapy of degenerated intervertebral discs, the height, volume or categorizing assessments, such as Pfirrmann classification, are used to quantify the discs themselves and the effects of therapy. Here, the question of transferability, in the sense of reliability, of the results arises in the common exchange. Methods: We have investigated two established and a newly developed (9-point measurement), easy to use methods for height measurement and volume measurement on degenerated and healthy lumbar intervertebral discs of 66 patients regarding inter- and intra-observer reliability. Results: In overview, we found very different reliabilities. While the intra-observer reliability showed good to excellent agreement for both healthy and degenerated lumbar discs for the height and volume measurements, the inter-observer reliability was low or moderate in some cases. The 9-point method for height determination consistently showed better reliability for both healthy and degenerated discs, for both intra- and inter-observer reliability, compared to the two established methods. Conclusions: We recommend using the 9-point measurement as the method to communicate lumbar disc height, both for healthy and degenerated discs. Due to the partly low or moderate reliability, significant differences in the measured heights can already occur, which can lead to a worsened comparability.

Background Context: The diagnosis of discogenic low back pain (LBP) from disc degeneration of the lumbar spine is often evaluated with discography. Noninvasive, simple screening methods other than invasive discography are useful, as evidence supporting clinical findings and magnetic resonance imaging (MRI) have come to the forefront.Purpose: To investigate disc height (DH) discrepancy between supine and standing positions on simple radiography to clarify its clinical screening value in individuals with discogenic LBP.Study Design/settings: Retrospective matched cohort design.Patient Sample: Ninety-two patients with early to middle stage disc degeneration (Pfirrmann grade II, III, or IV).Outcome Measures: Each subject underwent simple radiographs and MRI. Baseline characteristics, including demographic data and MRI findings, and radiological findings, including DH discrepancy, segmental angle, and sagittal balance, were analyzed. DH discrepancy ratio was calculated as (1 - [calibrated DH on standing radiography/calibrated DH on supine radiography]) × 100%.Methods: We matched LBP group of 46 patients with intractable discogenic pain (≥7 of visual analog scale scores) confirmed by discography with control group of 46 patients with similar stage disc degeneration with mild LBP (≤4 of visual analog scale scores). Binary regression analysis, receiver operating characteristic curve analysis, and cut-off value for diagnosis were used to evaluate and clarify diagnostic value of various factors.Results: There was no significant difference between the two groups in terms of baseline characteristics, including age, sex, body mass index, pathological level, and magnetic resonance findings such as disc degeneration, high intensity zone, and para-spinal muscle volume. Among the various radiological findings, the calibrated mean DH in the standing position (20.87±5.65 [LBP group] vs. 26.95±3.02 [control group], p<.001) and the DH discrepancy ratio (14.55±6.13% [LBP group] vs. 1.47±0.75% [control group], p=.007) were significantly different between the two groups. The cut-off value for DH discrepancy ratio to screen discogenic LBP was ≥6.04%. Additionally, as a compensation for pain, sagittal vertical axis (3.43±2.03 cm [LBP group] vs. -0.54±3.05 cm [control group], p=.002) and pelvic incidence (54.74±6.76° [LBP group] vs. 43.98±8.67° [control group]; p=.006) were different between the two groups.Conclusions: The results suggest that DH discrepancy between the supine and standing positions could be a screening metric for discogenic LBP in early to middle stage disc degeneration of the lumbar spine. [ABSTRACT FROM AUTHOR]

Introduction: Despite that lateral lumbar interbody fusion (LLIF) is a minimally invasive surgery, some patients complain of severe site pain immediately after the surgery. This study aimed to explore the extent of perioperative pain after LLIF, compare the degree of perioperative pain after LLIF with that after other surgical procedures, and evaluate the factors associated with severe pain in the early postoperative period., Methods: In this study, 93 patients who underwent lumbar spine surgeries for lumbar degenerative diseases were analyzed. The patients were categorized into three groups based on the surgical procedure: Group L, LLIF with percutaneous pedicle screw (PPS); Group P, posterolateral fusion (PLF) or posterior lumbar interbody fusion (PLIF); and Group D, posterior decompression (fenestration). The extent of low back pain was evaluated using the visual analog scale (VAS) preoperatively and from postoperative days 1 to 14., Results: The VAS score for postoperative pain decreased in a time-dependent manner in all three groups (P<0.01). Repeated measures analysis of variance (ANOVA) showed that the VAS in Group L was significantly higher than that in Group D (P<0.01). Time point analysis revealed that the VAS scores from postoperative days 1 to 9 in Group L were significantly higher than those in Group D (P<0.05). No significant difference was observed in the VAS scores of postoperative pain between Groups L and P on all postoperative days. The VAS score for early postoperative pain in Group L was significantly correlated with the change in disc height index (P<0.05, r=0.43) and tended to be associated with the grade of preoperative disc degeneration and the VAS score of preoperative low back pain (P=0.076-0.19)., Conclusions: This study is the first to evaluate the factors associated with pain during the early postoperative period of LLIF. Although LLIF is a minimally invasive surgery, severe pain may develop in patients with significant preoperative disc degeneration or following spinal correction surgery., Competing Interests: Conflicts of Interest: The authors declare that there are no relevant conflicts of interest., (Copyright © 2024 The Japanese Society for Spine Surgery and Related Research.)

Study Design Retrospective cohort study (level of evidence: 4). Purpose To describe the potential comorbid, operative, and radiographic risk factors for the development of clinically-relevant pseudarthrosis following minimally-invasive transforaminal lumbar interbody fusion (MIS-TLIF). Overview of Literature MIS-TLIF has shown long-term clinical outcomes with decreased perioperative morbidity and earlier return to work, similar to those of open TLIF. However, unsuccessful fusion still remains a concern. The impacts of various patient, operative, and radiographic risk factors have not been evaluated for their potential association with pseudarthrosis related to MIS-TLIF. Methods Between 2012 and 2015, 204 consecutive patients underwent one or two-level MIS-TLIF at St. Joseph's University Medical Center, Paterson, NJ, USA; they had a minimum of 1 year of follow-up. The patients were divided into two cohorts: those who developed clinically-relevant pseudarthrosis and those who did not. Clinically-relevant pseudarthrosis was determined by both evidence on computed tomography and presence of continued clinical symptoms at 1-year follow-up. Results Revision surgery was the only identified non-radiographic factor associated with pseudarthrosis. Disc angle had the highest (R2=0.8), followed by anterior disc height (R2=0.79). Although posterior disc height and the ratio of anterior to posterior disc height showed a marked relationship with the outcome, the R2-values were

Purpose: Expandable titanium transforaminal lumbar interbody fusion (TLIF) devices are a relatively new group of implants allowing restoration of lumbar lordosis (LL) and thus improvement of sagittal alignment. The purpose of our study is to compare clinical and radiological results of two different expandable TLIF devices. Materials and Methods: In a retrospective study, patients who underwent TLIF surgery with a banana-shaped or straight TLIF cage in our spine center were analyzed. Primary outcome was change of disc height (DH), segmental lordosis angle (SLA), and lumbar lordotic angle (LLA). Moreover, basic patients parameters and cage subsidence were evaluated. Results: Sixty-one patients were studied (33 banana-shaped and 28 straight cages). DH changed in the banana group from 4.8 mm (standard deviation SD 2.5) to 10.4 (SD 2.4) and in the straight cage group from 6.2 mm (SD 2.5) to 9.6 mm (SD 1.7). The difference was statistically significant (P = 0.03). In addition, SLA correction was higher in the banana group with 5.8° (SD 5.0)–3.7° (SD 3.6), but not significant. LLA improved in the straight group with 5.2 (SD 6.4) compared to 3.7° (SD 5.8) in the banana group. We found subsidence in four patients (6.6%) in the banana-shaped group and nine cases (14.8%) in the other group. Conclusions: Expandable titanium implants show similar improvements in restoring segmental and global lordosis. Banana-shaped expandable cages offer higher potency restoring the intervertebral DH and show less rates of subsidence compared to straight expandable cages.

Study Design: Retrospective matched cohort analysis.Objective: The aim of this study was to investigate the impact of adjacent level ossification development (ALOD) on the affected as well as the next-level discs with regards to range of motion (ROM) and degenerative changes.Summary Of Background Data: Although ALOD is not a rare condition in patients who undergo anterior cervical fusion procedures, there has been little discussion to date about its clinical implications.Methods: Patients who underwent anterior cervical instrumented fusion with a minimum 2-year follow-up were reviewed. Twelve patients with each respective ossification grade (totally 48 patients) were matched based on age, sex, and number of fusion levels. On the preoperative and final follow-up x-rays, disc height, osteophytes, ROM, and maximal listhesis were assessed at the segments which were one- (the adjacent segment) and two-level cranial (the next segment) to the uppermost fused disc. Then, the patients were divided into two groups according to ALOD degree: group 1 (grade 0-1, N = 24) versus group 2 (grade 2-3, N = 24). The changes of all variables were compared between the two groups.Results: The mean ROM of the adjacent segment increased by 3.6 degree in group 1 and conversely decreased by 2.8 degree in group 2 (P = 0.002). The mean ROM increase of the next segment was significantly greater in group 2 than in group 1 (4.5 vs. 1.2 degree, P = 0.016). The osteophyte growth and the progression of listhesis at the next segment were significantly greater in group 2 (P < 0.05). Disc height of the next segment significantly decreased in group 2, but did not change in group 1.Conclusion: Severe ALOD (grade 2-3) following anterior cervical fusion significantly reduced ROM at the affected segment and conversely increased motion at the next segment. This increased motion probably accelerated the degeneration of the next-level disc.Level Of Evidence: 3. [ABSTRACT FROM AUTHOR]

Study Design: A retrospective cohort study.Objective: To determine the risk factors of cage subsidence in patients undergoing minimally invasive transforaminal lumbar interbody fusion (MI-TLIF) and its correlation with patient-reported outcomes.Summary Of Background Data: Cage subsidence is among the cage-related complications after TLIF and may lead to poor outcomes. Few studies have addressed the incidence of cage subsidence in MI-TLIF.Methods: This retrospective study of a prospectively collected database was conducted from October 2015 to October 2017. All patients received MI-TLIF with a minimum of 2-year follow-up. All levels were separated into the cage subsidence (CS group) and no cage subsidence (non-CS group) groups. Cage subsidence was evaluated using lateral radiographs and defined as more than 2 mm migration of the cage into the endplate of adjacent vertebral body. Patient demographics, perioperative details, and radiographic parameters were recorded. Cage-related parameters were cage height, cage insertion level, and cage position. Cage position was recorded using central point ration (CPR). Patient-reported outcome was analyzed using the Oswestry Disability Index (ODI) questionnaire and Visual Analog Scale (VAS) preoperatively and at 2 years postoperatively.Results: Ninety-three patients (126 levels) were included. Mean age was 66.5 years with an average follow-up of 36.9 months. Overall incidence of cage subsidence was 34.1%. The CS group had significantly higher body mass index, less bone mineral density (BMD), shorter disc height, and higher CPR than the non-CS group. BMD, disc height, and CPR were significantly negatively correlated with depth of cage subsidence. ODI improvement was significantly lesser in the CS group than in the non-CS group. Fusion rate and complications were unrelated to cage subsidence.Conclusion: The BMD, disc height, and cage position were the most significant risk factors that were negatively correlated with depth of cage subsidence. Placing a TLIF cage anteriorly if possible may reduce the risk of cage subsidence.Level Of Evidence: 3. [ABSTRACT FROM AUTHOR]