Eight-Year Prevalence Trends of Lumbar Spondylolysis and Isthmic Spondylolisthesis in Adolescent Males: A Population-Based Study from a Nationwide Military Draft Medical Examination Database in South Korea.

OBJECTIVE: To assess the national and regional trend in the prevalence of lumbar spondylolysis and isthmic spondylolisthesis for adolescent males in South Korea from 2015 to 2022. METHODS: A total of 2,666,277 Korean adolescent males were routinely examined at regional Military Manpower Administration offices. The data gathered from Military Manpower Administration were retrospectively collected to measure the prevalence and 95% confidence interval of lumbar spondylolysis and isthmic spondylolisthesis according to the year and region in South Korea. The Spearman correlation analysis was performed to assess the correlation between lumbar spondylolysis, isthmic spondylolisthesis, and several factors including height, weight, current smoking rate, and occasional and high-risk alcohol consumption. RESULTS: The prevalence of spondylolysis per 10,000 individuals showed a gradual increasing trend from 2015 to 2022 On the contrary, the prevalence of isthmic spondylolisthesis per 10,000 individuals decreased over a consecutive 8-year period. There were no statistical differences in the prevalence of spondylolysis and isthmic spondylolisthesis between Greater Seoul and the countryside. The prevalence of isthmic spondylolisthesis was significantly correlated with occasional (r=0.81, P=0.015) and high-risk alcohol consumption (r=0.86, P=0.007). CONCLUSIONS: The prevalence of lumbar spondylolysis among adolescent men has increased, whereas isthmic spondylolisthesis has shown a decline over a consecutive 8-year period. The trends in prevalence for both lumbar spondylosis and isthmic spondylolisthesis were similar across the regions in South Korea. Notably, there was a significant correlation between the prevalence of isthmic spondylolisthesis and the rate of alcohol consumption in adolescent men.

Anatomical Parameters of Percutaneous, Minimally Invasive, Direct Intralaminar Pars Screw Fixation of Spondylolysis.

OBJECTIVE: To investigate the anatomical parameters of the ideal screw trajectory for percutaneous intralaminar screw fixation of a pars defect in lumbar spondylolysis using computed tomography scans. METHODS: Using advanced radiological software, the ideal intralaminar screw trajectory was determined. The anatomical parameters of this trajectory were analyzed using a total of 80 single-level lumbar tomography scans in patients with spondylolysis at the lumbar 4 vertebrae and lumbar 5 vertebrae levels. The ideal intralaminar screw trajectory started from the inferolateral edge of the lamina and was between the intralaminar region, pars defect, and defective pars neck and pedicle. Along this trajectory, the skin-lamina distance, intralaminar screw length, isthmic lamina length and width, defective pars neck width, lateral entry distance of the screw to the center of the spinous process, and sagittal and coronal screw application angles were analyzed. RESULTS: When comparing the lumbar 4 vertebrae and lumbar 5 vertebrae parameters, the mean skin-to-lamina distances were 11-9 cm (P = 0.000), intralaminar screw lengths 3.5-3.6 cm (P = 0.067), isthmic lamina lengths 2-2 cm (P = 0.698), mid-lamina widths 1-1 cm (P = 0.941), defective pars neck widths 1-1 cm (P = 0.674), screw lateral entry distances according to the spinous process 1-1.5 cm (P = 0.000), sagittal screw angles 45°-45° (P = 0.870), and coronal screw angles 10°-20° (P = 0.000), respectively. There were no differences based on age and gender (P < 0.05). CONCLUSIONS: Percutaneous intralaminar rigid screw fixation of a pars defect in spondylolysis provides minimally invasive, low-profile instrumentation. In spondylolysis, a screw length of 3-4 cm and a screw diameter of 4-5 mm may be sufficient for pars fixation with intralaminar screws.

Combined Transforaminal Lumbar Interbody Fusion and Smiley Face Rod Technique Using Dual-Headed Pedicle Screws for L4 Isthmic Spondylolisthesis and L5 Spondylolysis.

Spondylolysis with pseudarthrosis may be treated surgically by repairing the spondylolysis using the smiley face rod (SFR) technique. The SFR technique can avoid adjacent segmental disease caused by transforaminal lumbar interbody fusion (TLIF), which is one of the main surgical techniques to treat isthmic lumbar spondylolisthesis. A 59-year-old woman had been playing softball since she was 12 years old and was a member of a prefectural representative team. She sought treatment because of numbness in her left lower limb and difficulty playing softball. Despite conservative treatment for a year, her symptoms did not improve. Physical examination revealed decreased patellar tendon reflexes and numbness and pain from the front of the thigh to the lower leg without muscle weakness. Imaging showed L4 isthmic spondylolisthesis with Meyerding classification grade 2 anterior slip and L5 spondylolysis with pseudarthrosis. We diagnosed L4 radiculopathy caused by L4/5 foraminal stenosis and L4 isthmic spondylolisthesis with L5 spondylolysis. She underwent surgery combining the TLIF of L4/5 and the SFR technique of L5 using dual-headed pedicle screws that can fix two types of rods with L5 pedicle screws. Three months after surgery, fusion between L4/5 and fusion of the L5 pars cleft were confirmed. She resumed sports, and one year postoperatively, she was able to participate in softball games. Two years postoperatively, she could bat, run, and play defense without adjacent segmental disease. Two-segment TLIF increases adjacent segmental disease more than single-segment TLIF. Because the L5 spondylolysis had not slipped, we chose the SFR technique to preserve mobility at L5/S1. The dual-headed pedicle screw fastens two-type rods at the head of the pedicle screw, making it a suitable design for this procedure.

Percutaneous Transforaminal Endoscopic Lumbar Foraminotomy in Stable Degenerative Lumbar Isthmic Spondylolisthesis with Radicular Leg Pain: A Retrospective Study.

Objective: Endoscopic surgery is a minimally invasive option for effectively addressing lumbar degenerative diseases. This study aimed to describe the specific technology of percutaneous transforaminal endoscopic lumbar foraminotomy (PTELF) as a therapeutic intervention for managing radicular leg pain (RLP) resulting from stable degenerative lumbar isthmic spondylolisthesis (DLIS) and to present the associated clinical results. Methods: From March 2022 and April 2023, 25 patients were diagnosed with single-level stable DLIS with RLP and underwent PTELF. Clinical assessments utilized the visual analog scale (VAS), Oswestry Disability Index (ODI), and modified MacNab criteria. All endoscopic surgery videos were reviewed to interpret the pathology associated with DLIS. Results: The mean age of the cohort was 65.3 ± 11.0 years. The mean preoperative ODI score, VAS score for low back, and VAS score of the leg were 64.1 ± 8.2, 7.0 ± 0.7, and 7.3 ± 0.8, respectively. These scores significantly improved to 16.3 ± 10.4, 2.0 ± 0.6, and 1.7 ± 1.0 at the final follow-up, respectively (P<0.01). The modified MacNab criteria indicated "good" or "excellent" outcomes in 92.0% of cases. Analysis of 23 surgical videos revealed 15 patients with disc herniation, nine with lower vertebral endplate involvement, consistent presence of uneven bone spurs (at the proximal lamina stump and around the foramen), and accumulated scars. Two patients experienced postoperative dysesthesia, and one encountered a recurrence of RLP. Conclusion: PTELF emerges as a potentially safe and effective procedure for alleviating RLP in patients with stable DLIS. However, additional evidence and extended follow-up periods are imperative to evaluate the feasibility and potential risks associated with PTELF.

Reconsideration and Reflection on Spinal Disorders Through the Study of Intervertebral Discs in Patients with Lumbar Spondylolisthesis.

OBJECTIVE: This study analyzed and explored the relationship between isthmic spondylolisthesis and disc degeneration by comparing the degree of disc degeneration in patients with isthmic spondylolisthesis, lumbar disc herniation, and asymptomatic healthy individuals. METHODS: This study included a total of 138 cases, consisting of L5-S1 single segment lesion patients and a normal lumbar spine population. The cases were divided into 3 groups based on the type of disease: fifty eight cases in the isthmic spondylolisthesis (IS) group, 50 cases in the lumbar disc herniation (LDH) group, and 30 cases in the normal lumbar vertebrae (NLV) group. RESULTS: The research findings indicate that the proportion of intervertebral disc degeneration in the LDH group is significantly higher than that in the IS group and NLV group (65.3% vs. 33.3% vs. 25.8%, P < 0.05). The Pfirrmann grades of lumbar intervertebral discs (L1-L4) in the LDH group are significantly higher than those in the IS group and NLV group (P < 0.05), and the intervertebral height index (IHI) (L1-L4) of lumbar vertebrae in the LDH group is significantly lower than that in the IS group and NLV group (P < 0.05). CONCLUSIONS: The results showed that the degree of intervertebral disc degeneration in patients with isthmic spondylolisthesis was lighter than that in patients with LDH, and even similar to that in healthy individuals. The occurrence of IS may have slowed down the degeneration of nonaffected segment intervertebral discs through certain factors.

Transforaminal Endoscopic Lumbar Foraminotomy for the Treatment of L5-S1 Isthmic Lumbar Spondylolisthesis with Foraminal Stenosis: A 1-Year Follow-Up.

BACKGROUND: Isthmic lumbar spondylolisthesis (ILS) is a prevalent spinal pathology. Radicular pain in patients is often attributed to L5-S1 ILS combined with foraminal stenosis (FS), making such patients prime candidates for surgical intervention. We herein aimed to elucidate the surgical technique and clinical outcomes of transforaminal endoscopic lumbar foraminotomy (TELF) in the treatment of L5-S1 ILS with FS. METHODS: From September 2021 to December 2022, 20 consecutive patients were diagnosed with L5-S1 ILS with FS and underwent TELF. All patients were followed up for at least 12 months. The clinical outcomes were evaluated using the visual analog scale (VAS), Oswestry Disability Index, and modified MacNab criteria. RESULTS: The mean age of the patients was 62.4 ± 10.9 years. The mean preoperative VAS score for low back, VAS score of the leg, and Oswestry Disability Index score was 5.1 ± 1.7, 7.4 ± 0.7, and 58.0 ± 8.4, respectively. These scores significantly improved to 1.8 ± 0.7, 1.5 ± 0.6, and 15.3 ± 7.1 at 12 months postoperatively, respectively (P < 0.01). Evaluation based on the modified MacNab criteria revealed that 95.0% of patients achieved a good-to-excellent outcome. One patient underwent revision surgery. CONCLUSIONS: TELF emerges as a potentially safe and effective surgical option for alleviating radicular pain in patients with L5-S1 stable ILS combined with FS. While our short-term clinical results are satisfactory, it is necessary to expand the sample size and extend the follow-up time to validate the effectiveness and long-term efficacy of TELF.

Clinical and radiological outcomes of gradual reduction and circumferential fusion of high-grade spondylolisthesis in adolescents: a prospective cohort study of 29 young patients.

AIM: The objective of this study was to evaluate the safety and efficacy of a novel technique of formal reduction and circumferential fusion for pediatric high-grade spondylolisthesis (HGS). PURPOSE: The safety and efficacy of formal reduction for high-grade spondylolisthesis (HGS) has never been thoroughly examined. This study reports the outcomes of 29 children with HGS who underwent a procedure of gradual reduction and circumferential fusion. METHODS: 29 children (13 males, 16 females) were recruited between 2006 and 2010. Radiographic measurements (including % of slip, lumbosacral angle-LSA, pelvic incidence-PI, pelvic tilt-PT, sacral slope-SS, and proximal femoral angle-PFA) and quality of life assessment (SRS-22 questionnaire) were prospectively obtained at baseline and at the last post-operative follow-up (> 2 years post-op). Radiological measurements were used to classify patients according to the Spine Deformity Study Group (SDSG) classification. RESULTS: Mean baseline slip % was 69.9 ± 16.5%. There were 13 patients with a balanced pelvic (SDSG Type 4) and 16 with an unbalanced pelvis (SDSG Type 5 and 6). On average, a reduction of 45.5 ± 15.3% (range 20-86%) was achieved safely with no major complication. In particular, of the 29 patients, only 3 had a L5 radiculopathy postoperatively that was self-resolved at follow-up. From a radiological standpoint, we observed a mean improvement of LSA from 80.3 ± 17.9° to 91.7 ± 13.6°. We also observed a statistically significant improvement in global HRQOL, and in the function and body image domains. CONCLUSION: This prospective study suggests that formal reduction of HGS followed by circumferential fusion is safe when using a standardized surgical technique based on gradual reduction. Performing this intervention could also help improve QOL in some patients.

Posterolateral Fusion Versus Posterior Lumbar Interbody Fusion for Adult Low-Grade Isthmic Spondylolisthesis: Analysis of Sagittal Radiographic Parameters - A Randomized Controlled Trial.

STUDY DESIGN: Randomized controlled trial. OBJECTIVES: To compare the effect of posterolateral fusion (PLF) and posterior lumbar interbody fusion (PLIF) on sagittal radiographic parameters in patients with low-grade isthmic spondylolisthesis. Additionally, to explore the correlation between changes in these parameters and clinical outcomes. METHODS: Forty-six consecutive patients with single-level low-grade isthmic spondylolisthesis were initially enrolled. They were randomly assigned to undergo either PLF or PLIF. Patients were followed up for at least 24 months. Radiographic outcomes included pelvic incidence, pelvic tilt, sacral slope, lumbar lordosis, sagittal vertical axis, T1 pelvic angle, slip angle, slip degree and disc height. Clinical outcomes were assessed by the Oswestry Disability Index (ODI) and visual analogue scale (VAS). RESULTS: Four participants were lost to follow-up. Of the remaining 42 patients, 29 were female. The mean age was 40.23 ± 10.25 years in the PLF group and 35.81 ± 10.58 years in the PLIF group. There was a statistically significant greater correction of all radiographic parameters in the PLIF group. The ODI and VAS improved significantly in both groups, with no significant differences between the two groups. Changes in the ODI and VAS were significantly correlated with changes in disc height, slip angle and lumbar lordosis. CONCLUSIONS: In patients with low-grade isthmic spondylolisthesis, PLIF demonstrates superior efficacy compared to PLF in correcting sagittal radiographic parameters. Nevertheless, this distinction does not seem to influence short-term clinical results. Restoring disc height, correcting the slip angle, and reestablishing normal lumbar lordosis are crucial steps in the surgical management of isthmic spondylolisthesis.

What are the differences in paraspinal muscle morphometry among degenerative spondylolisthesis patients, isthmic spondylolisthesis patients, and healthy individuals? A propensity score matching analysis.

PURPOSE: To compare the morphometry of paraspinal muscles in patients with degenerative spondylolisthesis (DS), isthmic spondylolisthesis (IS), and healthy individuals. METHODS: Thirty-seven pairs of DS patients were selected using propensity score matching with IS patients, while 37 healthy individuals matched for age, sex, and BMI were selected as controls. The relative cross-sectional area (rCSA), and relative functional cross-sectional area (rfCSA) of paraspinal muscles were measured, and the degree of fatty infiltration (FI) was calculated. Based on occupational differences, the patients were also divided into worker and farmer groups, and the same measurements were taken on them. RESULTS: At the L3/L4 level, the multifidus (MF) FI was greater in the DS and IS groups than in the control group, the erector spinae (ES) rfCSA was higher in the IS group than in the DS and control groups. At the L4/L5 level, MF rfCSA was smaller in the DS and IS groups than in the control group; ES rfCSA was higher in the IS group than in the DS and control groups. At the L5/S1 level, MF rfCSA was smaller in the DS and IS groups than in the control group; ES rfCSA was higher in the IS group than in the DS group. At the L3/L4, L4/L5 level, MF rfCSA were higher in the worker group than in the farmer group (p < 0.05). CONCLUSION: The morphological changes in paraspinal muscles in patients with DS were dominated by selective atrophy of the MF, while in patients with IS, the morphological changes in paraspinal muscle showed selective atrophy of the MF accompanied by compensatory hypertrophy of the ES. The surgeon should consider the morphological differences in paraspinal muscle between different types of lumbar spondylolisthesis when establishing the appropriate surgical program.

Fetal Aortic Blood Flow Velocity and Power Doppler Profiles in the First Trimester: A Comprehensive Study Using High-Definition Flow Imaging.

OBJECTIVES: This study aimed to establish reference values for fetal aortic isthmus blood flow velocity and associated indices during the first trimester, utilizing a novel ultrasonographic technique known as high-definition flow imaging (HDFI). Additionally, the correlation between Doppler profiles of aortic blood flow and key fetal parameters, including nuchal thickness (NT), crown-rump length (CRL), and fetal heartbeat (FHB), was investigated. METHODS: A total of 262 fetuses were included in the analysis between December 2022 and December 2023. Utilizing 2D power Doppler ultrasound images, aortic blood flow parameters were assessed, including aortic peak systolic velocity (PS), aortic end-diastolic velocity (ED), aortic time average maximal velocity (TAMV), and various indices such as aortic systolic velocity/diastolic velocity (S/D), aortic pulsatile index (PI), aortic resistance index (RI), aortic isthmus flow velocity index (IFI), and aortic isthmic systolic index (ISI). Concurrently, fetal FHB, NT, and CRL were evaluated during early trimester Down syndrome screening. RESULTS: Significant findings include a positive correlation between gestational age (GA) and PS (PS = 3.75 × (GA) - 15.4, r2 = 0.13, p < 0.01), ED (ED = 0.42 × (GA) - 0.61, r2 = 0.04, p < 0.01), PI (PI = 0.07 × (GA) + 1.03, r2 = 0.04, p < 0.01), and TAMV (TAMV = 1.23 × (GA) - 1.66, r2 = 0.08, p < 0.01). In contrast, aortic ISI demonstrated a significant decrease (ISI = -0.03 × (GA) + 0.57, r2 = 0.05, p < 0.05) with gestational age. No significant correlation was observed for aortic RI (p = 0.33), S/D (p = 0.39), and IFI (p = 0.29) with gestational age. Aortic PS exhibited positive correlations with NT (0.217, p = 0.001) and CRL (0.360, p = 0.000) but a negative correlation with FHB (-0.214, p = 0.001). Aortic PI demonstrated positive correlations with CRL (0.208, p = 0.001) and negative correlations with FHB (-0.176, p = 0.005). Aortic TAMV showed positive correlations with NT (0.233, p = 0.000) and CRL (0.290, p = 0.000) while exhibiting a negative correlation with FHB (-0.141, p = 0.026). Aortic ISI demonstrated negative correlations with NT (-0.128, p = 0.045) and CRL (-0.218, p = 0.001) but a positive correlation with FHB (0.163, p = 0.010). CONCLUSIONS: Power Doppler angiography with Doppler ultrasound demonstrates the ability to establish accurate reference values for fetal aortic blood flow during the first trimester of pregnancy. Notably, aortic PS, TAMV, and ISI exhibit significant correlations with NT, CRL, and FHB, with ISI appearing more relevant than IFI, PS, TAMV, and FHB. The utilization of HDFI technology proves advantageous in efficiently detecting the site of the aortic isthmus compared to traditional color Doppler mode in early second trimesters.

Imaging predictors of progression of lumbar spondylolysis to spondylolisthesis: a systematic review.

BACKGROUND CONTEXT: Isthmic spondylolisthesis (IS) is defined as the anterior translation of one lumbar vertebra relative to the next caudal segment as a result of a unilateral or bilateral fracture of the pars interarticularis. These fractures are interchangeably known as "pars defects" or "spondylolysis." Many risk factors have been proposed to explain the progression of a spondylolytic defect to IS, however, none are validated. PURPOSE: This systematic review provides an overview of various radiological and imaging parameters that can help predict the risk of progression of a spondylolytic defect into IS. STUDY DESIGN: Systematic review. METHODS: Medline, Embase and Cochrane online database were searched. The various correlations between imaging features with observed spondylolisthesis prevalence or severity or spondylolysis rates of spondylolisthesis were evaluated to provide a list of imaging risk factors to predict IS. Significance of the correlations in the original article was recorded to enable comparison of the collected evidence of separate image features. RESULTS: All searches combined generated a total of 431 results of which 26 articles were included into this study. Of the 22 potential risk factors identified, 5 were found to be statistically insignificant, 8 were found to be significant and 9 had mixed results. The following features were found to be significant risk factors in at least on study: disc degeneration, transverse process width, pelvic incidence, pelvic tilt, sacral slope, lumbar lordosis, lumbar index, thoracic kyphosis, facet joint angle above the level of defect, facet joint degeneration, facet tropism, multifidus size, lateral erector spinae size, mesenteric fat thickness, subcutaneous fat thickness and soft tissue calcification. CONCLUSION: Our research suggests that only disc degeneration had moderately strong evidence with consistent significant associations with development of IS in patients with spondylolysis. Transverse process width, pelvic incidence, pelvic tilt, sacral slope, lumbar lordosis, lumbar index, thoracic kyphosis, facet joint angle above the level of defect, facet joint degeneration, facet tropism, multifidus size, lateral erector spinae size, mesenteric fat thickness, subcutaneous fat thickness and soft tissue calcification had some evidence. All other radiological factors had weak evidence. The results of this study can be used to improve early clinical decision making for patients with spondylolysis.

Amphiregulin Switches Progenitor Cell Fate for Lineage Commitment During Gastric Mucosal Regeneration.

BACKGROUND & AIMS: Isthmic progenitors, tissue-specific stem cells in the stomach corpus, maintain mucosal homeostasis by balancing between proliferation and differentiation to gastric epithelial lineages. The progenitor cells rapidly adopt an active state in response to mucosal injury. However, it remains unclear how the isthmic progenitor cell niche is controlled during the regeneration of damaged epithelium. METHODS: We recapitulated tissue recovery process after acute mucosal injury in the mouse stomach. Bromodeoxyuridine incorporation was used to trace newly generated cells during the injury and recovery phases. To define the epithelial lineage commitment process during recovery, we performed single-cell RNA-sequencing on epithelial cells from the mouse stomachs. We validated the effects of amphiregulin (AREG) on mucosal recovery, using recombinant AREG treatment or AREG-deficient mice. RESULTS: We determined that an epidermal growth factor receptor ligand, AREG, can control progenitor cell lineage commitment. Based on the identification of lineage-committed subpopulations in the corpus epithelium through single-cell RNA-sequencing and bromodeoxyuridine incorporation, we showed that isthmic progenitors mainly transition into short-lived surface cell lineages but are less frequently committed to long-lived parietal cell lineages in homeostasis. However, mucosal regeneration after damage directs the lineage commitment of isthmic progenitors towards parietal cell lineages. During recovery, AREG treatment promoted repopulation with parietal cells, while suppressing surface cell commitment of progenitors. In contrast, transforming growth factor-α did not alter parietal cell regeneration, but did induce expansion of surface cell populations. AREG deficiency impairs parietal cell regeneration but increases surface cell commitment. CONCLUSIONS: These data demonstrate that different epidermal growth factor receptor ligands can distinctly regulate isthmic progenitor-driven mucosal regeneration and lineage commitment.

The Short-Term Outcome of Transforaminal Epidural Steroid Injection in Patients with Radicular Pain Due to Foraminal Stenosis from Lumbar Isthmic Spondylolisthesis.

Purpose: In this study, we evaluated the therapeutic outcomes of transforaminal epidural steroid injection (TFESI) in managing chronic radicular pain due to foraminal stenosis. Furthermore, we evaluated its effectiveness according to isthmic spondylolisthesis (IS) severity. Patients and Methods: We included 40 patients with radicular pain due to IS-derived foraminal stenosis in our study and treated them with TFESI. Two patients were lost during follow-up. Based on the lateral lumbar radiograph findings, we allocated the recruited patients with < 25% slippage by IS to Group 1 (n = 23) and those having 25-50% slippage to Group 2 (n = 15). The degree of pain was measured using a numeric rating scale (NRS) at pre-treatment and 1 and 2 months after TFESI. Results: In 38 patients who completed the study, the NRS at pre-treatment was significantly reduced at the 1- and 2-month follow-ups. In the Group analysis, the NRS scores were significantly reduced after TFESI in both Groups 1 and 2, regardless of IS severity. However, the reduction in NRS scores 1 month after TFESI was significantly greater in Group 1 than in Group 2. Moreover, the rate of successful treatment outcomes was significantly higher (65.2%) in Group 1 than in Group 2 (26.7%). Conclusion: After TFESI, chronic radicular pain was significantly reduced regardless of IS severity, and its effect persisted for at least 2 months. However, its effect was superior when the vertebra slippage by IS was less than 25% compared to patients with 25%-50%.

Should there be a paradigm shift for the evaluation of isthmic thyroid nodules?

PURPOSE: Although the thyroid isthmus seems like a rudimentary structure that connects bilateral lobes, it is an undiscovered area that needs to be explored. Currently, the data is evolving that the increase in the risk of malignancy is higher in the isthmic nodules, and extrathyroidal extensions and lymph node metastases are more common in isthmic-derived malignant thyroid nodules. Therefore, we aimed to compare the malignancy rate of isthmic and lobar nodules, the ultrasonographic features of isthmic and lobar nodules, and presence of lymph node metastases, distant metastases, and extrathyroidal invasions in malignant isthmic nodules. METHODS: In this retrospective study, we enrolled patients between the ages of 18-80 years, who had thyroid nodule/nodules cytology and/or pathology results from January 2009 to November 2022. 9504 nodules were selected for the analysis of US findings, cytopathology results, and malignancy rates. RESULTS: A mean ± SD age of 55.3 ± 13.0 years with a female to male ratio of [7618 (80.2%)/1886(19.8%)] were included in the study. 962 of the nodules were at isthmic localization; whereas 8542 nodules were at lobar localization. 1188 nodules were resulted as malignant from histopathological evaluation. Of the 1188 malignant nodules, 986 nodules were (83.0%) PTC, 114 nodules (9.6%) were FTC, 55 nodules were (4.6%) MTC, 16 nodules 1.3% were Hurtle cell carcinoma, 8 nodules (0.7%) were anaplastic thyroid carcinoma, and 9 nodules (0.8%) were thyroid tumors of uncertain malignant potential (TT-UMP). 156 of the malignant nodules (13.1%) were located in the isthmus, whereas the majority of the malignant nodules (n = 1032, 86.9%) were located at the lobar parts (right or left) of the thyroid. When the metastasis patterns of isthmic and lobar thyroid cancers were examined, no significant relationship was found between isthmic and lobar cancers in terms of capsule invasion (p = 0.435), muscle invasion (p = 0.294), and lymph node metastasis (p = 0.633). A significant relation was found between nodule localization (isthmus-upper-middle and lower lobes) and malignancy (p < 0.001). In our logistic regression analysis, isthmic and upper pole nodule localizations, age and TI-RADS were evaluated as independent risk factors for malignancy (p < 0.001 for all factors). CONCLUSION: We recommend nodule localization has to be considered an additional risk factor when performing a Fine Needle Aspiration Biopsy for the increased malignancy risk in this localization.

Return to flight duty (RTFD) after posterior lumbar spine surgery for symptomatic lumbar disc herniation (LDH) and lumbar isthmic spondylolisthesis (LIS) in Chinese military pilots.

BACKGROUND: Symptomatic lumbar disc herniation (LDH) and lumbar isthmic spondylolisthesis (LIS) present significant challenges for military pilots, which may result in grounding if not effectively managed. Surgical treatment for LDH and LIS may offer a pathway to return to flight duty (RTFD), but recent data on this crucial topic is lacking. This study seeks to address this gap by investigating the RTFD outcomes among Chinese military pilots who have undergone lumbar spine surgery for symptomatic LDH and LIS. METHODS: A retrospective review was conducted on active-duty military pilots who underwent isolated decompressive or fusion procedures at an authorized military medical center from March 1, 2007, to March 1, 2023. The analysis utilized descriptive statistics to examine demographic, occupational, surgical, and outcome data, with a particular focus on preoperative flight status, recommended clearance by spine surgeons, and actual RTFD outcomes and time. RESULTS: Among the identified cases of active-duty military pilots with LDH or LIS treated by lumbar surgery (n = 24), 70.8% (17 of 24) consistently maintained RTFD status without encountering surgical complications or medical issues during the follow-up period. Of the seven pilots who did not RTFD, one retired within a year of surgery, two had anterior cruciate ligament injuries, three had residual radicular symptoms, and one had chronic low back pain. Excluding pilots who retired and did not RTFD for reasons unrelated to their lumbar conditions, the RTFD rate stood at 81.0% (17 of 21). The median time for recommended clearance by spine surgeons was 143.0 days (inter-quartile range, 116.5-196.0), while the median duration for actual RTFD attainment was 221.0 days (inter-quartile range, 182.0-300.0). The median follow-up post-lumbar surgery was 1.7 years (inter-quartile range, 0.4-2.9). CONCLUSION: Most military pilots diagnosed with symptomatic LDH and LIS can continue their careers and regain active-duty flight status following lumbar spine surgery, as reflected by the high RTFD rate. Lumbar spine surgery can successfully alleviate the physical constraints associated with spinal conditions, facilitating the return of military pilots to their demanding profession.

L4/5 Disc Herniation: Not Unusually Accompanied with L5/S1 Low-Grade Spondylolytic Spondylolisthesis.

OBJECTIVE: Isthmic spondylolisthesis (IS) is distinguished by a congenital defect or acquired fracture of the pars interarticularis. Numerous studies on L5 low-grade IS have been carried out; however, there is a paucity of data regarding the condition of L5 IS concomitant with L4/5 disc herniation. This study aimed to identify the incidence rate and to illustrate the possible risk factors for L4/5 disc herniation in L5 low-grade IS patients. METHODS: A total of 268 consecutive patients diagnosed as L5/S1 low-grade IS between May 2017 and May 2022 were retrospectively enrolled in this study. Depending on the presence of L4/5 disc herniation or not, patients were divided into an L4/5 disc herniation group (L4/5 DH) and an L4/5 non-disc herniation group (L4/5 non-DH). Radiographic parameters were measured, and the ratios of L4-S1 segmental lordosis (SL) to lumbar lordosis (LDI), L4 inferior endplate (IEP) to L5 superior endplate (SEP) (L4 IEP/L5 SEP), and L5 IEP to S1 SEP (L5 IEP/S1 SEP) were compared between groups. The Pfirrmann grade of the L4/5 disc and the L5/S1 disc, and Roussouly classifications of each patient were also recorded. Univariate analysis (including independent-samples t-test and χ2 -test) and multiple logistic regression analysis were performed to analyze the data. RESULTS: There were 40 patients (14.9%) in the L4/5 DH group. The Roussouly classification differed significantly between groups. As demonstrated by the Pfirrmann grade, the L4/5 DH group showed more advanced disc degeneration at L4/5 than the L4/5 non-DH group. In contrast to the L4/5 non-DH group, the L4/5 DH group had a significantly larger L4 IEP, L4 IEP/L5 SEP, S1 SEP, and LDI while smaller L4/5 disc angle, L4/5 disc height, slip percentage, lumbar lordosis, and sacral slope. Multivariate logistic regression analysis revealed that higher L4/5 disc Pfirrmann grade (p = 0.004), decreased L4/5 disc height (p < 0.001), and lower L5 slip percentage (p = 0.022) were significantly associated with the occurrence of L4/5 DH. CONCLUSIONS: L4/5 disc herniation is not unusually accompanied by L5/S1 low-grade IS. Advanced L4/5 disc degeneration, decreased L4/5 disc height, and lower L5 slip percentage might be significantly associated with L4/5 disc herniation.

Real-time ultrasound demonstration of uterine isthmus contractions during pregnancy.

BACKGROUND: Asymptomatic isthmic contractions are a frequent physiological phenomenon in pregnancy, sometimes triggered by bladder voiding. They can interfere with proper cervical length assessment and may lead to false images of placenta previa. However, there is limited research on the prevalence and characteristics of these contractions. OBJECTIVE: This study aimed to determine the prevalence and characteristics of isthmic contractions after bladder voiding in the second trimester of pregnancy, to evaluate their effect on cervical length assessment, and to propose a new method for the objective assessment of the presence and intensity of isthmic contractions. STUDY DESIGN: In this prospective observational study, long videos of the uterine cervix were recorded in 30 singleton pregnancies during the second trimester of pregnancy after bladder voiding. Isthmic length and cervicoisthmic length changes were assessed over time. The isthmic length was measured using a new approach, which involved calculating the distance from the base of the cervix to the internal os, including the isthmus. RESULTS: Isthmic contractions were observed in 43% of pregnant women (95% confidence interval, 26%-62%) after bladder voiding. The median time for complete isthmus relaxation was 19.7 minutes (95% confidence interval, 15.0 to not available). No substantial differences in maternal characteristics were found between individuals with and without contractions. The proposed method for measuring isthmic length provided an objective assessment of the presence and intensity of isthmic contractions. A cutoff of 18 mm in isthmic length allowed for the distinction of pregnant women presenting a contraction. In addition, the study identified a characteristic undulatory pattern in the relaxation of the isthmus in half of the cases with contractions. CONCLUSION: Isthmic contractions are a common occurrence after bladder voiding in the second trimester of pregnancy and may interfere with proper cervical length assessment. We recommend performing cervical assessment at least 20 minutes after bladder voiding to reduce the risk of bias in cervical length measurement and to avoid false images of placenta previa. The new method for measuring isthmic length provides an objective way to assess the presence and intensity of isthmic contractions. Further research is needed to understand the role of isthmic contractions in the physiology of pregnancy and birth.

Enrichment of FGF8-expressing cells from neurally induced human pluripotent stem cell cultures.

In early vertebrate development, organizer regions-groups of cells that signal to and thereby influence neighboring cells by secreted morphogens-play pivotal roles in the establishment and maintenance of cell identities within defined tissue territories. The midbrain-hindbrain organizer drives regionalization of neural tissue into midbrain and hindbrain territories with fibroblast growth factor 8 (FGF8) acting as a key morphogen. This organizer has been extensively studied in chicken, mouse, and zebrafish. Here, we demonstrate the enrichment of FGF8-expressing cells from human pluripotent stem cells (hPSCs), cultured as attached embryoid bodies using antibodies that recognize "Similar Expression to Fgf" (SEF) and Frizzled proteins. The arrangement of cells in embryoid body subsets of these cultures and the gene expression profile of the FGF8-expressing population show certain similarities to the midbrain-hindbrain organizer in animal models. In the embryonic chick brain, the enriched cell population induces formation of midbrain structures, consistent with FGF8-organizing capability.

Correlation Analysis Between Computed Tomography and Magnetic Resonance Imaging for Assessing Thoracic Pedicle Morphology.

OBJECTIVE: This study aimed to determine the accuracy and reliability of using magnetic resonance imaging (MRI) to characterize thoracic pedicle morphology in the normal population. METHODS: Computed tomography (CT) and MRI datasets of 63 surgically treated patients were included in the study. Bilateral T3, T6, T9, and T12 vertebral levels were evaluated for the type of pedicle, pedicle chord length, and pedicle isthmic diameter on both MRI and CT scans. Pedicles were classified according to Sarwahi et al. into type A (normal pedicle), >4 mm cancellous channel; type B, 2-4 mm channel; type C, completely cortical channels >2 mm; and type D, <2 mm cortical bone channel. RESULTS: Of 504 pedicles, 294 were classified as type A, 173 as type B, 24 as type C, and 13 as type D based on a CT scan. MRI had an overall accuracy rate of 92.86% for detecting type A, 96.53% for type B, and 100% for type C and type D compared with CT scans. Regarding the thoracic levels, MRI had an overall concordance of 97.98% at T3 level, 94.43% at T6 level, 98.11% at T9 level, and 99.3% at T12 level with CT readings. Comparing measurements between MRI and CT studies for pedicle isthmic diameter and pedicle chord length showed moderate to good reliability at all measured levels. CONCLUSIONS: Pedicle measurements obtained by MRI may be used to estimate pedicle dimensions, allowing surgeons to preoperatively determine pedicle screw sizes based on MRI scans alone.

Analysis of Degenerative and Isthmic Lumbar Spondylolisthesis from the Difference of Pelvic Parameters and the Degree of Degeneration through Imaging Data.

BACKGROUND: In previous studies, many imaging analyses have been conducted to explore the changes in the intervertebral disc degeneration (DD), facet joint osteoarthritis (FJOA), L4 inclination angle (L4IA), pelvis-related parameters, lumbar lordosis (LL), and paravertebral muscle (PVM) in the occurrence and development of degenerative spinal diseases via measuring the X-ray, CT, and MRI data of clinical patients. However, few studies have quantitatively investigated the pelvic parameters and the degree of spine degeneration in patients with degenerative lumbar spondylolisthesis (DLS) and isthmic lumbar spondylolisthesis (ILS). This study discusses the changes in the imaging parameters of DLS, ILS, and a control group; explores the correlation between different measurement parameters; and discusses their risk factors. METHODS: We evaluated 164 patients with single L4-L5 grade 1 level degenerative lumbar spondylolisthesis (DLS group), 161 patients with single L4-L5 grade 1 level isthmic lumbar spondylolisthesis (ILS group), and 164 patients with non-specific back pain (control group). The grades of DD and FJOA as well as the percentage of the fat infiltration area (%FIA) of multifidus muscle (MM) at the L4-L5 level were measured via CT and MRI. Lumbar lordosis (LL), pelvic incidence (PI), pelvic tilt (PT), the L4 inclination angle (L4IA), and sacral slope (SS) were measured via X-ray film, and the differences among the DLS group, ILS group, and control group were analyzed. Furthermore, the risk factors related to the incidences of the DLS and ILS groups were discussed. RESULTS: First, the pelvis-related parameters of DLS and ILS patients were 51.91 ± 12.23 and 53.28 ± 11.12, respectively, while those of the control group were 40.13 ± 8.72 (p1 < 0.001, p2 < 0.001). Lumbar lordosis (LL) in DLS patients (39.34 ± 8.57) was significantly lower than in the control group (44.40 ± 11.79, p < 0.001). On the contrary, lumbar lordosis (LL) in the ILS group (55.16 ± 12.31) was significantly higher than in the control group (44.40 ± 11.79, p < 0.001). Secondly, the three groups of patients were characterized by significant variations in the L4 inclination angle (L4IA), disc degeneration (DD), facet joint osteoarthritis (FJOA), pelvis-related parameters, and paravertebral muscle (PVM) (p < 0.05). Finally, logistic regression suggests that the L4IA, FJOA, and PT may be risk factors for the occurrence of DLS, and the occurrence of ILS is correlated with the L4IA, FJOA, DD, PT, and LL. CONCLUSIONS: Compared with the control group, there are changes in pelvic parameters, the L4IA, LL, DD, FJOA, and PVM in DLS and ILS patients, and the degree is different. The parameters within the same group are related to each other, and DLS and ILS have different risk factors. The mechanical stability of the spine is affected by the parameter and angle changes, which may be of great significance for explaining the cause of spondylolisthesis, evaluating the health of the lumbar spine, and guiding the lifestyles of patients.