L3 Level Research Articles

Outpatient minimally invasive spine surgeries during the COVID-19 pandemic – A retrospective analysis of 164 consecutive cases

ObjectiveTo share our surgical experiences of minimally invasive cervical and lumbar procedures for patients who suffered from non-fatal motor vehicle accidents (MVAs) in the ambulatory surgery centers (ASCs) during the coronavirus disease 2019 (COVID-19) pandemic. MethodsAnterior cervical discectomy and fusion (ACDF), anterior lumbar interbody fusion (ALIF), minimally invasive laminotomy and discectomy (MILD), percutaneous endoscopic laser-assisted discectomy (PELD) and percutaneous kyphoplasty (PK) were performed on carefully selected patients. ResultsFrom January 2020 to December 2021, our group performed 164 cases on 153 patients involving 249 intervertebral disc (IVD) levels. Of these, 116 cases (70.73%) on 114 patients (74.51%) were cervical, 48 cases (29.27%) were lumbar (including 8 PK cases). Eight patients had both cervical and lumbar procedures in a single anesthetic session (SAS) and were discharged on the same day. One hundred and six ACDF cases (92.17%) were at the C4–C5 and C5–C6 levels, which comprised of 146 (76.04%) IVDs. Of the 40 non-PK lumbar cases, 38 (95.0%) were at L4 to S1 lumbar levels. Six of these cases (15.0%) involved 2 lumbar levels. In contrast, 6 out of 8 kyphoplasties (75.0%) involved lower thoracic/higher lumbar vertebral columns (T11 to L2) and 2 were at the lower lumbar L4 level. ConclusionsWe successfully and safely performed various cervical and lumbar spine surgeries in the ASCs amid COVID-19 pandemic and all patients achieved the same-day discharge (SDD). In the non-fatal MVAs, mid-lower cervical (C4 to C6) and lower lumbar (L4 to S1) IVDs were the most affected levels.

Changes in spinopelvic relationships in children with spondylolisthesis after surgical treatment and their correlation with the assessment of quality of life

Objective. To assess sagittal balance parameters in children with spondylolisthesis before and after surgical treatment and to analyze their correlation with quality of life.Material and Methods. A retrospective analysis of postural radiographs of 98 children and adolescents was performed. The patients were divided into 2 groups: Group 1 included 43 patients under 17 years of age (mean age 12.0 ± 2.6 years) without spinal pathology, and Group 2 – 55 patients under 17 years of age (mean age 13.3 ± 2.5 years) with spondylolisthesis before and after surgical treatment. In patients of Group 1, the main spinopelvic parameters (PT, PI, SS, LL, PI-LL, TK) were calculated and studied. In patients of Group 2, parameters characterizing local lumbosacral kyphosis (SA, Dub-LSA, LSJA) were calculated and studied in addition to the main ones. The obtained results were compared with the conditional norm for children. The intensity of pain syndrome and quality of life were assessed using questionnaires and scales (Ped`s QL, ODI, VAS) before surgical treatment, at the time of discharge from the hospital, and after 3 months since surgery. Statistical data analysis was carried out using the statistical programming language and the R environment (version 3.6.1) in RStudio IDE (version 1.2.1335) with representation in the M ± SD format for normally distributed random variables and Me [Q1; Q3] for variables with abnormal distribution. Categorical indicators were presented as an absolute number and a percentage ratio. The null hypothesis in statistical tests was rejected at a significance level of p < 0.05Results. A decrease in the intensity of pain syndrome and an improvement in the quality of life were observed after surgical treatment in all cases. Statistical analysis of the relationship between parameters characterizing local lumbosacral kyphosis (Dub-LSA, SA, LSJA) and the results of using questionnaires and scales (Ped`s QL, ODI, VAS) showed a statistically significant positive correlation (r = 0.57; p = 0.004) of the LSJA score and pain intensity assessed before surgery, as well as a statistically significant negative correlation (r = -0.47; p = 0.004) of the LSJA score before surgery and the results of the PED`s QL questionnaire after surgery. In a comparison group analysis, it was found that after surgical treatment, there was a tendency towards normalization of sagittal parameters, though their complete recovery to normal values was not achieved. Local lumbosacral kyphosis was completely eliminated in all cases.Conclusion. Correction of the angle of lumbosacral kyphosis during surgical treatment of children with spondylolisthesis directly correlates with indicators characterizing the quality of life, which makes its elimination the main purpose of the operation. The degree of correction of the sagittal balance parameters (PT, SS, LL) has no significant impact on the quality of life, and their correction to the target calculated values is not required at an initially high PI value. In cases of decompensation of the sagittal and coronal balances of the trunk with low grades of spondylolisthesis, combined with impaired gait and anterior inclination of the torso (lumbar-femoral rigidity syndrome), the instrumental restoration of segmental lordosis at the level of L5–S1 and decompression of neural structures lead to correction of sagittal balance and normalization of gait.

Intradural Extramedullary Capillary Hemangioma of Spinal Cord: A Case Report and an Updated Review

Background and Importance: Capillary hemangiomas are benign tumors found on the skin and soft tissues. They rarely present as an intradural spinal tumor. Common differential diagnosis methods are schwannoma, hemangioblastoma, metastasis, and paragangliomas. Case Presentation: We report a case of a 38-year-old female with complaints of lower backache with radiation to lower limbs, in which the magnetic resonance imaging revealed an intradural tumor compressing the cauda equina nerve roots, arising from the L3 level. The patient underwent L2-L3 laminectomy with tumor excision with the preservation of nerve roots. Conclusion: Histopathology suggested capillary hemangioma and the patient improved symptomatically and no recurrence has been reported to date.

1629-P: Association between Dyslipidemia and Myosteatosis Evaluated by Abdominal Computed Tomography

Introduction: The association between dyslipidemia and myosteatosis measured using muscular quality map in abdominal computed tomography(CT) was analyzed in a large population. Methods: Abdominal CT of 20,210 subjects were evaluated to measure total abdominal muscle area (TAMA) at L3 level. TAMA was segmented into intramuscular adipose tissue and skeletal muscle area (SMA), which was further classified into normal attenuation muscle area (NAMA: good quality muscle) and low attenuation muscle area (LAMA: poor quality muscle). Myosteatosis indices used were SMA/body mass index(BMI), NAMA/BMI, NAMA/TAMA, and LAMA/BMI. Dyslipidemia was defined as high-density lipoprotein cholesterol(HDL-C) less than 40mg/dL in men and 50mg/dL in women, low-density lipoprotein cholesterol(LDL-C) greater than 160mg/dL, or triglycerides(TG) greater than 150mg/dL. Results: According to multiple logistic regression analyses, the odds ratios (ORs) of dyslipidemia according to HDL and LDL definitions showed a decreasing trend with increasing quartiles for SMA/BMI, NAMA/BMI, and NAMA/TAMA (P for trend < 0.001 for all). The adjusted ORs (95% confidence intervals[CIs]) for dyslipidemia in Q2, Q3, and Q4 for NAMA/TAMA compared with Q1 were 0.87 (0.79-0.96), 0.76 (0.69-0.85) and 0.55 (0.49-0.61) according to the HDL definition and 0.93 (0.83-1.05), 0.95 (0.84-1.07), and 0.69 (0.60-0.79) according to the LDL definition. Conversely, the ORs of dyslipidemia according to HDL and LDL showed an increasing trend according to increasing LAMA/BMI quartiles (P for trend < 0.001 for all). Dyslipidemia according to TG did not show a significant association after adjustment. Conclusion: Dyslipidemia according to HDL-C and LDL-C definitions is associated with myosteatosis, positively with bad quality (unhealthy) muscle and negatively with good quality (healthy) muscle. Muscle quality may be an important risk factor for dyslipidemia and ensuing cardiometabolic diseases. Disclosure H.Kim: None. H.Jung: None. Y.Cho: None. W.Lee: None. C.Jung: None.

Porphyrin-based ligand interaction with G-quadruplex: Metal cation effects.

The G-quadruplex planar-ligand complex is used to detect heavy metal cations such as Ag+ , Cu2+ , Pb2+ , Hg2+ , organic molecules, nucleic acids, and proteins. The interaction of the three planar porphyrins (L1), 5,10,15,20-tetrakis (1-ethyl-1-λ4 -pyridine-4-yl) porphyrin (L2), and 5,10,15,20-tetrakis (1-methyl-1-λ4 -pyridine-4-yl) porphyrin (L3), coming from the porphyrin family, with G-quadruplex obtained from human DNA telomeres in the presence of lithium, sodium, potassium, rubidium, cesium, magnesium, and calcium ions was studied by molecular dynamics simulation. When G-quadruplex containing divalent ions of magnesium and calcium interacts with L1, L2, and L3 ligands, the hydrogen bonds of the lower G-quadruplex sheet are more affected by ligands and the distance between guanines in the lower tetrad increases. In the case of G-quadruplex interactions containing monovalent ions with ligands, the hydrogen bond between the sheets does not follow a specific trend. For example, in the presence of lithium ions, the upper and middle sheets are more affected by ligands, while they are less affected by ligands in the presence of sodium. The binding pocket and the binding energy of the three ligands to the G-quadruplex were also obtained in the various systems. The results show that ligands make the G-quadruplex more stable through the penetration between the sheets and the interaction with the loops. Among the ligands mentioned, the interaction level of the ligand L2 is greater than the others. Our calculations are consistent with the previous experimental observations so that it can help to understand the molecular mechanism of porphyrin interaction and its derivatives with the G-quadruplex.

Is Tranexamic Acid an Effective Prevention in the Formation of Epidural Fibrosis? Histological Evaluation in the Rats.

The present study aimed to determine the topical and systemic efficacy of tranexamic acid (TXA) on epidural fibrosis in a rat laminectomy model. Thirty-two 12-month-old adult Sprague-Dawley rats were used in this study. Each rat underwent bilateral laminectomy at the L1 and L2 vertebral levels. Rats were divided into four groups : in group I (control group, n=8), a laminectomy was performed and saline solution was applied into the surgical space. In group II (topical group, n=8), laminectomy was performed and 30 mg/ kg TXA was applied to the surgical site before skin closure. In group III (systemic group, n=8), 30 mg/kg TXA was administered intravenously via the tail vein in the same session as the surgical procedure. In group IV (topical and systemic group, n=8), TXA was administered 30 mg/kg both topical and intravenous. The rats were sacrificed at 4 weeks postoperatively. Masson's trichrome and hematoxylin and eosin were used to assess acute inflammatory cells, chronic inflammatory cells, vascular proliferation, and epidural fibrosis. Epidural fibrosis, acute inflammation, chronic inflammation, and sum histologic score value were significantly lower in the systemic TXA group, systemic and topical TXA groups than in the control group (p<0.05). In addion, the sum histologic score was significantly lower in the topical TXA group than in the control group (p<0.05). In this study, epidural fibrosis formation was prevented more by systemic application, but the topical application was found to be effective when compared to the control group. As a result, we recommend the systemic and topical use of TXA to prevent epidural fibrosis during spinal surgery.

28-LB: Role of Glycine N-methyltransferase in Electronegative Lipoproteins-Induced Vascular Dysfunction in a Diabetic Rodent Model

Several studies showed low-density lipoprotein (LDL) is associated with high risk of atherosclerosis in patients with diabetes. However, aggressively decreasing total LDL does not prevent all vascular complications. A novel culprit electronegative LDL (L5) was significantly increased in diabetic patients and could induce vascular damage according to our previous studies. However, the mechanism of L5 formation and how to reduce plasma L5 level are still unclear. In the present study, we found both aqueous and ethylacetate extracts of a traditional Chinese remedy Artemisia capillaris (AC) could decrease plasma L5 level in western diet-fed hamster (22.45 and 28.64 vs. 56.83%, respectively), while clinical remedies Simvastatin and Niacin could not. AC could also reverse western diet-induced vascular senescence (b-gal staining) and relaxation dysfunction in aortic rings (63.66±2.14 vs 40.13±1.48% of maximum contraction when compared to western diet hamsters; P&amp;lt;0.01). To further determine the underlying mechanism, we have found that AC reversed western diet-reduced Glycine N-methyltransferase (GNMT) protein abundance and altered several microRNA expression by analyzing the microarray heatmap in liver tissue. In conclusion, AC could significantly reverse western diet-induced vascular injury by lowering plasma L5 level through restore the liver enzyme GNMT activity. Disclosure A. Lee: None. Y. Chen: None. W. Chen: None.

Intrathecal Adjuvant Midazolam Versus Fentanyl With Hyperbaric Bupivacaine for Post-operative Analgesia in Women Undergoing Total Abdominal Hysterectomy.

Background The administration of adequate analgesia post-operatively has been associated with fewer cardiopulmonary complications, lower morbidity and mortality, lower healthcare costs, and higher patient satisfaction. One of the most effective ways to raise the standard of healthcare would bestandardization of multimodal analgesia with enhanced recovery after surgery. Adjuncts to spinal anesthetists can achieve a better post-operative pain relief with less doses of rescue analgesia. Methods This was a prospective, randomized trial conducted on 60 women undergoing abdominal hysterectomy under spinal anesthesia. We evaluated the impact of adding 0.5 mL (2.5 mg) of intrathecal midazolam versus25 mcg of intrathecal fentanyl (0.5 mL) with 2.5 mL injection of0.5% bupivacaine (hyperbaric) (12.5 mg). The outcomes were prolongation of analgesia in the post-operative period, onset and duration of sensory and motor blockade,stable hemodynamics, andany adverse reactions to the study drugs. Results The two groups, group M (midazolam + hyperbaric bupivacaine) and group F (fentanyl + hyperbaric bupivacaine), had similar distribution for age, weight, and type and duration of surgical procedure. Both groups had stable vital parameters and experienced a similar onset of sensory and motor blockade. Intraoperative modified Ramsay sedation score was better in group M in comparison to group F. However, mean of elapsed time oftwo-segment regressionof sensory block, from T12 to L1 level, and mean time to regression, from Bromage score 3 to 2, were longer in group F. Group F also had a better visual analogue scale (VAS) score in the post-operative period than group M, and group F experienced a longer average post-operative analgesic duration (lasting for 367.73 minutes) as compared to group M (lasting for 254.9 minutes), having a difference that was of statistical significance (p < 0.001).No substantial adverse reactions were seen in either group. Conclusion The duration of post-operative analgesia is significantly prolonged when 25 mcg of adjuvant intrathecal fentanylis usedwith 0.5% bupivacaine (hyperbaric)as compared to intrathecal midazolam 0.5 mL (2.5 mg) in women undergoing abdominal hysterectomy under spinal anesthesia. Both fentanyl and midazolam have minimal adverse reactions and are safe to use as adjuvants to 0.5% of bupivacaine (hyperbaric) in surgeries conducted in the lower abdomen.

Reference distributions of aortic calcification and association with Framingham risk score

Evidence supporting aortic calcification as a leverageable cardiovascular risk factor is rapidly growing. Given aortic calcification’s potential as a clinical correlate, we assessed granular vertebral-indexed calcification measurements of the abdominal aorta in a well curated reference population. We evaluated the relationship of aortic calcification measurements with Framingham risk scores. After exclusion, 4073 participants from the Reference Analytic Morphomic Population with varying vertebral levels were included. The percent of the aortic wall calcified was used to assess calcification burden at the L1–L4 levels. Descriptive statistics of participants, sex-specific vertebral indexed calcification measurements, relational plots, and relevant associations are reported. Mean aortic attenuation was higher in female than male participants. Overall, mean aortic calcium was higher with reference to inferior abdominal aortic measurements and demonstrated significant differences across all abdominal levels [L3 Area (mm^2): Females 6.34 (sd 16.60), Males 6.23 (sd 17.21); L3 Volume (mm^3): Females 178.90 (sd 474.19), Males 195.80 (sd 547.36); Wall Calcification (%): Females (L4) 6.97 (sd 16.03), Males (L3) 5.46 (13.80)]. Participants with elevated calcification had significantly higher Framingham risk scores compared to participants with normal calcification scores. Opportunistically measuring aortic calcification may inform further cardiovascular risk assessment and enhance cardiovascular event surveillance efforts.

Lumbar Discal Cyst: Is it a Rare Consequence in Lumbar Disc Disease Spectrum? Short Case Series with Review of Literature and Hypothesis Regarding Etiopathogenesis

Abstract Background Lumbar discal cysts are rare intraspinal extradural lesions presenting as lumbar radiculopathy. The rarity of the lesion is sufficient to evoke interest in its diagnosis. The hitherto unsolved etiopathogenesis prompted us to look into these areas in this study. Objectives 1) To review the literature and summarize the clinicoradiological and histopathological features of the discal cyst. 2) To investigate possible mechanisms in the etiopathogenesis of discal cysts. Materials and Methods Three patients presented with features suggestive of lumbar disc prolapse and were diagnosed with discal cyst over 1.5 years and were included in this study. All patients underwent lumbar spine magnetic resonance imaging (MRI) and were subsequently treated by cyst excision. The final diagnosis of the discal cyst was based on histopathological features. Results Out of three patients, two had a discal cyst with disc prolapse, and one had a discal cyst alone. Discal cyst patient underwent excision of cyst alone. Discal cyst patients with disc prolapse underwent discectomy in addition to excision of the discal cyst. One patient had an L2–L3 level discal cyst with disc prolapse, which is uncommon. Conclusions Lumbar discal cysts, although rare, form an important differential diagnosis in patients with lumbar radiculopathy. They have a distinctive MRI appearance, and because discal cyst and disc prolapse shared similar etiopathological features, we hypothesize that discal cyst is a part of the degenerative disc disease spectrum. We also conclude that discal cyst excision should be coupled with discectomy when LDC is associated with disc prolapse.

Anterior Quadratus Lumborum Block and Quadriceps Strength: A Prospective Cohort Study.

The decrease in quadriceps strength after anterior quadratus lumborum block (AQLB) has not been quantified. This prospective cohort study investigated the incidence of quadriceps weakness after AQLB. We enrolled patients undergoing robot-assisted partial nephrectomy, and AQLB was performed at the L2 level with 30 mL of 0.375% ropivacaine. We evaluated each quadriceps' maximal voluntary isometric contraction using a handheld dynamometer preoperatively and postoperatively at 1 and 4 days. The incidence of muscle weakness was defined as a 25% reduction in muscle strength compared with the preoperative baseline, and "muscle weakness possibly caused by nerve block" was defined as a 25% reduction compared with the non-block side. We also assessed the numerical rating scale and quality of recovery-15 scores. Thirty participants were analyzed. The incidence of muscle weakness compared with preoperative baseline and the non-block side was 13.3% and 30.0%, respectively. Patients with a numerical rating scale ≥ 4 or quality of recovery-15 score < 122, which was classified as moderate or poor, had decreased muscle strength with relative risks of 1.75 and 2.33, respectively. All patients ambulated within 24 h after surgery. The incidence of quadriceps weakness possibly caused by nerve block was 13.3%; however, all patients could ambulate after 1 day.

What is the role of CT-based Hounsfield unit assessment in the evaluation of bone mineral density in patients undergoing 1- or 2-level lumbar spinal fusion for degenerative spinal pathologies? A prospective study

Computed tomography-based vertebral attenuation values (CT-based HU) have been shown to correlate with T-scores on DEXA scan; and have been acknowledged as an independent factor for predicting fragility fractures. Most patients undergoing lumbar surgeries require CT as part of their preoperative evaluation. The current study was thus planned to evaluate the role of lumbar CT as an opportunistic investigation in determining BMD preoperatively in patients undergoing lumbar fusion. Prospective cohort study. Patients older than 45 years, who underwent one- to two-level lumbar (L3-S1 levels) fusions. Comparison of the quantitative assessment of osteoporosis using Hounsfield Units (HU) on CT (L1-L5) and mean lumbar T-scores on DEXA (Dual Energy X-ray Absorptiometry). HU on CT is comparable to T-score on DEXA as a suitable modality for the assessment of osteoporosis in patients undergoing one- to two-level lumbar fusion. A prospective cohort study was conducted between January and December 2021. Patients older than 45 years, who underwent one- to two-level lumbar (L3-S1 levels) fusions and had complete clinico-radiological records, were prospectively enrolled. A comparison was drawn between the HU (measured by placing an oval region of interest [ROI] over axial, sagittal and coronal images of lumbar vertebrae) on CT and T-scores on DEXA, and analyzed statistically. The HU values correlating best with normal (group A), osteopenia (B) and osteoporosis (C) categories (classified based on T-scores of lumbar spines) were determined statistically. Overall, 87 patients (mean age of 60.56±11.63 years; 63 [72.4%] female patients) were prospectively studied. There was a statistically significant difference in the mean age (p=.01) and sex distribution (predominantly female patients; p=.03) of patients belonging to groups B (osteopenic) and C (osteoporotic patients), as compared with group A. The greatest correlation between T-score (on DEXA) and HU (on CT) for differentiating osteopenia (group B) from group A was observed at levels L1 (p<.001), L2 (p<.001) and L3 (p<.001). Based on receiver-operating characteristic (ROC) curve analysis, the cut-off values for HU for identifying osteopenia were 159 (at L1; sensitivity 81.6 and specificity 80) and 162 (at L2; sensitivity 80 and specificity 71.1). In addition, there was statistically significant correlation between T-score (on DEXA) and HU at all the lumbar levels for distinguishing osteoporosis (group C), although the difference was most evident at the upper lumbar (L1 and L2) levels (p<.001). Based on ROC analysis, cut-off HU values for defining osteoporosis were 127 (at L1; sensitivity 71.3 and specificity 70) and 117 (at L2; sensitivity 65.5 and specificity 90). Based on our study, the measurement of HU on CT at upper lumbar levels can be considered as "surrogate marker" for BMD in the diagnosis of osteopenia (cut-off: 159 at L1, 162 at L2) and osteoporosis (cut-off: 127 at L1, 117 at L2) in patients undergoing lumbar fusion surgeries. The HU measurements on CT at the lower lumbar levels (L4 and L5) are less reliable in this preoperative scenario.

Two-year Skeletal Effects of Sleeve Gastrectomy in Adolescents with Obesity Assessed with Quantitative CT and MR Spectroscopy.

Background Sleeve gastrectomy (SG) is effective in the treatment of cardiometabolic complications of obesity but is associated with bone loss. Purpose To determine the long-term effects of SG on vertebral bone strength, density, and bone marrow adipose tissue (BMAT) in adolescents and young adults with obesity. Materials and Methods This 2-year prospective nonrandomized longitudinal study enrolled adolescents and young adults with obesity who underwent either SG (SG group) or dietary and exercise counseling without surgery (control group) at an academic medical center from 2015 to 2020. Participants underwent quantitative CT of the lumbar spine (L1 and L2 levels) to assess bone density and strength, proton MR spectroscopy to assess BMAT (L1 and L2 levels), and MRI of the abdomen and thigh to assess body composition. Student t and Wilcoxon signed-rank tests were used to compare 24-month changes between and within groups. Regression analysis was performed to evaluate associations between body composition, vertebral bone density, strength, and BMAT. Results A total of 25 participants underwent SG (mean age, 18 years ± 2 [SD], 20 female), and 29 underwent dietary and exercise counseling without surgery (mean age, 18 years ± 3, 21 female). Body mass index (BMI) decreased by a mean of 11.9 kg/m2 ± 5.21 [SD] after 24 months in the SG group (P < .001), while it increased in the control group (mean increase, 1.49 kg/m2 ± 3.10; P = .02). Mean bone strength of the lumbar spine decreased after surgery compared with that in control subjects (mean decrease, -728 N ± 691 vs -7.24 N ± 775; P < .001). BMAT of the lumbar spine increased after SG (mean lipid-to-water ratio increase, 0.10 ± 0.13; P = .001). Changes in vertebral density and strength correlated positively with changes in BMI and body composition (R = 0.34 to R = 0.65, P = .02 to P < .001) and inversely with vertebral BMAT (R = -0.33 to R = -0.47, P = .03 to P = .001). Conclusion SG in adolescents and young adults reduced vertebral bone strength and density and increased BMAT compared with those in control participants. Clinical trial registration no. NCT02557438 © RSNA, 2023 See also the editorial by Link and Schafer in this issue.

Sarcopenia vs body mass index (BMI) as a prognostic biomarker in patients with metastatic clear cell renal cell carcinoma (mCCRCC) in the era of first line immune checkpoint inhibitors (ICIs).

e16515 Background: ICIs are an important systemic treatment option for patients with mCCRCC. Sarcopenia, defined as low muscle mass, is associated with inferior outcomes in mCCRCC. However, there is limited data regarding sarcopenia and overall survival (OS) in patients receiving treatment with ICI-based regimens. Our objective was to evaluate associations between sarcopenia and BMI with OS in patients with mCCRCC receiving first line ICIs. Methods: A retrospective review of patients with mCCRCC receiving first line ICI-based therapy at Fred Hutchinson Cancer Center between 1/2015 to 4/2022 was performed. Patients without CT scans within 75 days of treatment initiation were excluded. Skeletal muscle index (SMI) at the level of L3 was measured using validated techniques. Sarcopenia was classified according to an international definition (SMI &lt; 55 cm2/m2 for men and SMI &lt; 39 cm2/m2 for women). BMI was defined as underweight ( &lt; 19 kg/m2), normal (19-24.99kg/m2), overweight (25-29.99 kg/m2), and obese ( &gt; 30 kg/m2). OS was estimated using the Kaplan-Meier method. Associations with OS were evaluated with Cox proportional hazard model analysis. Results: A total of 96 patients (25% female) with a median age of 62 (Interquartile range, IQR 55-68), met inclusion criteria. Due to missing CT images, 9 (9%) patients were excluded. 10 (11%), 43 (49%), and 22 (25%) were International Metastatic RCC Database Consortium (IMDC) favorable, intermediate, and poor risk respectively (12 unknown). Median follow up was 23 months (IQR 12-35). First-line therapy included ICI monotherapy (N = 15), ipilimumab/nivolumab (N = 49) or ICI/VEGF targeted therapy (N = 23). In total, 43 (49%) patients were sarcopenic. Median OS overall was 42.6 months (IQR 15.9-NR). Two-year OS was 57% in sarcopenic vs 76% in non-sarcopenic patients (Log-Rank p = 0.06). On multivariable analysis adjusted for IMDC risk criteria, age, and gender, SMI (continuous) was independently associated with survival (HR 0.94, 95%CI 0.90-0.99, p = 0.03) while BMI was not significantly associated with OS on univariate or multivariable analyses (p &gt; 0.05). Among the 49 patients receiving ipilimumab/nivolumab combination therapy, sarcopenia was significantly associated with decreased 2-year OS (47% vs. 77%, p = 0.02). Across IMDC risk strata, sarcopenia was significantly associated with decreased 2-year OS in the intermediate risk group only (44% vs. 83%, p = 0.01). Conclusions: Sarcopenia, but not BMI, is independently associated with OS among patients with mCCRCC receiving first line ICI-based regimens. This finding is consistent with the literature suggesting that muscle mass measurement provides an important prognostic biomarker for patients with mCCRCC. SMI could inform treatment selection and adoption of muscle measures when risk-stratifying this population should be considered.

ID: 217220 Treatment of Lumbar Facet Cyst Causing Radiculopathy With an Intra-Articular Facet Injection - Case Report

Lumbar facet cysts are an atypical cause of low back pain and radiculopathy [1,2]. Spinal synovial cysts are benign protrusions of facet joint capsules caused by degenerative spondylosis, most frequently involving the L4-5 level, that can cause mechanical impingement on the traversing nerve root [3,4]. While the typical recommended treatment involves surgical cyst resection, a less invasive, fluoroscopic-guided percutaneous approach may be an effective treatment to consider prior to surgery [1]. In this report, we present a case report of a patient with radicular back pain from a lumbar L4-5 facet cyst who was successfully treated with a percutaneous fluoroscopic-guided lumbar facet cyst rupture.

Sarcopenia and body fat change as risk factors for radiologic incisional hernia following robotic nephrectomy

ObjectiveTo assess the effect of body muscle and fat metrics on the development of radiologic incisional hernia (IH) following robotic nephrectomy.Materials and MethodsWe retrospectively reviewed the records of patients who underwent robotic nephrectomy for kidney tumors between 2011 and 2017. All pre- and postoperative CTs were re-reviewed by experienced radiologists for detection of radiologic IH and calculation of the following metrics using Synapse 3D software: cross-sectional psoas muscle mass at the level of L3 and L4 as well as subcutaneous and visceral fat areas. Sarcopenia was defined as psoas muscle index below the lowest quartile. Cox proportional hazard model was constructed to examine the association between muscle and fat metrics and the risk of developing radiologic IH.ResultsA total of 236 patients with a median (IQR) age of 64 (54–70) years were included in this study. In a median (IQR) follow-up of 23 (14–38) months, 62 (26%) patients developed radiologic IH. On Cox proportional hazard model, we were unable to detect an association between sarcopenia and risk of IH development. In terms of subcutaneous fat change from pre-op, both lower and higher values were associated with IH development (HR (95% CI) 2.1 (1.2–3.4), p = 0.01 and 2.4 (1.4–4.1), p < 0.01 for < Q1 and ≥ Q3, respectively). Similar trend was found for visceral fat area changes from pre-op with a HR of 2.8 for < Q1 and 1.8 for ≥ Q3.ConclusionBoth excessive body fat gain and loss are associated with development of radiologic IH in patients undergoing robotic nephrectomy.

A comparison of the sarcopenic effect of androgen receptor-axis-targeted agents vs. androgen deprivation alone in patients with metastatic prostate cancer.

Androgen deprivation therapy (ADT) with androgen receptor axis-targeted (ARAT) therapy is the standard of care provided to patients with metastatic prostate cancer. While effective, it results in sequelae, such as loss of skeletal muscle mass. In this study, we compared the sarcopenic effects of abiraterone and enzalutamide, two ARATs used to treat metastatic prostate cancer. Our cohort was comprised of 55 patients diagnosed with metastatic hormonenaive prostate cancer from 2014-2019. Patients were divided into three treatment groups: gonadotropin-releasing hormone (GnRH ) agonist alone; GnRH agonist combined with abiraterone acetate; and GnRH agonist combined with enzalutamide. We then compared axial computed tomographic (CT) scans at the L3 level before and after the initiation of hormone therapy for each patient. A skeletal muscle index (SMI) was calculated for each patient, and alongside clinical data, was compared between the three groups. One-way analysis of variance (ANOVA) and Fisher's exact test were used to compare means and proportions, respectively. Baseline clinical characteristics were not significantly different between the three groups. The percent SMI change and number of newly sarcopenic patients were not found to be significantly different between the groups. The only variable that was significantly different across the three groups was time between CT scans. Although we found no significant difference in the sarcopenic effects of GnRH alone, GnRH with abiraterone, or GnRH with enzalutamide in our cohort of 55 hormone-naive metastatic prostate cancer patients, overall decreases in muscle mass were observed for all three groups. This highlights the importance of muscle-retaining strategies for patients undergoing ADT for metastatic prostate cancer, regardless of therapeutic regimen.

A Study on Syntactic Complexity and Topic Difference Influence in Second Language Writing Based on Dependency Treebank

Using Stanford parser as a tool, taking 1840 articles on two topics by 920 English learners of four levels after random selection as the research corpus, this study attempts to explore the development trend of syntactic complexity of learners of different levels and what influence divergent topic can have on it. Results show that multi-level learners generally prefer adverbial clauses (advcl) and complement clauses (ccomp) to relative clauses (acl: recl); adjective modifiers (amod) are the best in distinguishing the level of English learners, which can be used as an important basis for judging the level of L2; in addition, different topics of the same task type have no significant effect on L2 learners’ syntactic complexity. It can be concluded that most syntactic complexity measures at the clause and phrase level show a non-linear development trend. Based upon the findings, implications are provided for English textbook development and English pedagogical practices.

Assessing the effects of sway-back posture on global and regional spinal sagittal angles using inertial measurement units.

Sway-back posture in the sagittal profile is a commonly adopted poor standing posture. Although the terms, definitions, and adverse health problems of sway-back posture are widely used clinically, few studies have quantified sway-back posture. To investigate spinal sagittal alignment in sway-back posture while standing based on global and regional angles using inertial measurement units (IMUs). This cross-sectional study recruited 30 asymptomatic young adults. After measuring the sway angle while standing, the participants were divided into sway-back and non-sway-back groups (normal thoracic group). Each participant stood in a comfortable posture for 5 seconds with IMUs at the T1, T7, T12, L3, and S2 levels. Then, we measured the global and regional lumbar and thoracic angles and sacral inclination in the standing position. Although there was no difference in the global lumbar angle, there was a difference in regional lumbar angles between the two groups. The normal thoracic group had balanced lumbar lordosis between the upper and lower lordotic arcs, whereas the sway back group tended to have a flat upper lumbar angle and increased lower lumbar angle. It is useful to assess the global and regional angles in the spinal sagittal assessment of individuals with sway-back posture.

Association between visceral obesity, metformin use, and recurrence risk in early-stage colorectal cancer

We sought to investigate the association between visceral obesity with disease recurrence and survival in early-stage colorectal cancer (CRC) patients. We also wanted to examine if such an association, if exists, is influenced by metformin use. Stage I/II CRC adenocarcinoma patients treated surgically were identified. L3 level CT VFI (visceral fat index) was used as a metric of visceral obesity and was calculated as the proportion of total fat area composed of visceral fat. N = 492. 53% were males, 90% were Caucasians, 35% had stage I disease, and 14% used metformin. 20.3% patients developed a recurrence over a median follow-up of 56 months. VFI was associated with both RFS and OS in a multivariate model, but not BMI. The final multivariate model for RFS included an interaction term for VFI and metformin (p = 0.04). Confirming this result, subgroup analysis showed an increasing VFI was associated with a poor RFS (p = 0.002), and OS (p < 0.001) in metformin non-users only and metformin use was associated with a better RFS only in the top VFI tertile (p = 0.01). Visceral obesity, but not BMI, is associated with recurrence risk and poorer survival in stage I/II CRC. Interestingly, this association is influenced by metformin use.