Posterior aggressive debulking versus minimal decompression surgery in patients with metastatic spinal cord compression: propensity-score-matching analysis from a multicenter study cohort.

OBJECTIVE: The goal of this study was to evaluate the comparative outcomes of aggressive debulking (AD) and minimal decompression (MD) surgeries for metastatic spinal cord compression based on surgical burden, functional improvement, and symptomatic local recurrence (SLR). METHODS: In this retrospective analysis from 2 tertiary hospitals, the authors assessed patients with metastatic spinal cord compression treated via AD and MD surgeries between 2010 and 2022. The evaluation included patient demographics, Eastern Cooperative Oncology Group performance status (ECOG-PS), primary tumor type, modified Tokuhashi scores, surgical burden, and SLR. Propensity-score matching (1:1 ratio) was conducted based on oncological status for intergroup comparisons. Survival analysis and logistic regression analyses were conducted. RESULTS: A total of 264 patients were included in the study. After 1:1 propensity-score matching, a total of 156 matched patients were analyzed (78 patients each in the AD and MD groups). Operation time, estimated blood loss, transfused red blood cell units, and inpatient medical complications were significantly higher in the AD group compared to the MD group (p = 0.001, p = 0.002, p = 0.006, and p = 0.035, respectively). There was no significant difference in distribution of postoperative ECOG-PS between the AD and MD groups (OR 1.461, 95% CI 0.821-2.599, p = 0.197). In initially nonambulatory patients (ECOG-PS of grade 3 or 4), the AD group showed a higher proportion of patients regaining ambulatory function compared to the MD group (56.5% vs 36.2%; OR 2.294, p = 0.049). In cases with a preoperative ECOG-PS of grade 3, the difference in ambulation recovery between AD and MD was not statistically significant (60.0% vs 53.3%, p = 0.577). However, for severely impaired patients (ECOG-PS of grade 4), the AD group showed a higher proportion of patients regaining ambulatory function compared to the MD group (33.3% vs 5.9%, p = 0.086). Symptomatic SLR-free survival showed no significant differences at final follow-up (p = 0.095). Multivariate analysis identified the modified Tokuhashi score as the sole predictor of SLR (OR 1.871, p = 0.001). CONCLUSIONS: This study found that MD surgery significantly reduced surgical burden compared to AD. AD surgery led to slightly better functional recovery showing greater rescue ratios, especially in patients with a preoperative ECOG-PS of grade 4. However, no difference in rescue ratio was observed in patients with a preoperative ECOG-PS of grade 3. There was no significant difference in SLR rates between the AD and MD groups.

Which prognostic model best predicts poor prognosis in patients with spinal metastases? A comparative analysis of 8 scoring systems.

BACKGROUND: Existing scoring system's comparative effectiveness in identifying patients with poor prognosis (i.e., <6 months survival) has not been thoroughly explored. METHODS: We compared the predictive performance of eight prognostic scoring systems (Tomita, modified Tokuhashi, modified Bauer, Rades, Oncological Spinal Prognostic Index, Lei, New England Spinal Metastasis Score, and the skeletal oncology research group (SORG) nomogram) with the area under curve (AUC) from receiver operating characteristic (ROC) curves and evaluated the predictive accuracy for 6-month survival across different primary tumor origins, and 1-month survival. Logistic regression was used to identify factors associated with 6-month survival. RESULTS: 641 patients with spinal metastasis treated between 1994 and 2022 were included. The SORG nomogram showed best performance with low discriminative power in predicting 6-month survival (AUC [95% confidence interval (CI)]: 0.664 [0.584-0.744]). Logistic regression analysis identified significant factors influencing 6-month survival, including primary cancer type in Lei's classification, preoperative Frankel grades C and D, or grades A and B compared with grade E, preoperative WBC, preoperative albumin, and preoperative chemotherapy. For 1-month survival predictions, both the SORG nomogram (AUC [95% CI]: 0.750 [0.648-0.851]) and modified Tokuhashi score (AUC [95% CI]: 0.667 [0.552-0.781]) showed significance, albeit with moderate to low discriminative power. CONCLUSIONS: This study shows that most scoring systems have low discriminative power, with only the SORG nomogram having moderate power for predicting poor prognosis. Recent and future advances in treatment, laboratory markers, and our understanding of tumor biology should be incorporated into prognostic models to improve their accuracy.

Characterization of Patients with Poor Clinical Outcome after Adult Spinal Deformity Surgery: A Multivariate Analysis of Mean 8-Year Follow-Up Data.

Background/Objective: Limited data exist regarding the long-term clinical outcomes and related factors after adult spinal deformity (ASD) surgery. This study aims to characterize patients who experienced poor clinical outcomes during long-term follow-up after ASD surgery. Methods: Patients who underwent ASD surgery with ≥5-vertebra fusion including the sacrum and ≥5-year follow-up were included. They were divided into two groups according to the Oswestry Disability Index (ODI) at the last follow-up: group P (poor outcome, ODI > 40) and group NP (non-poor outcome, ODI ≤ 40). Clinical variables, including patient factors, surgical factors, radiographic parameters, and mechanical complications (proximal junctional kyphosis [PJK] and rod fracture), were compared between the groups. Results: A total of 105 patients were evaluated, with a mean follow-up of 100.6 months. The mean age was 66.3 years, and 94 patients (89.5%) were women. There were 52 patients in group P and 53 patients in group NP. Univariate analysis showed that low T-score, postoperative correction relative to age-adjusted pelvic incidence-lumbar lordosis, T1 pelvic angle (TPA) at last follow-up, and PJK development were significant factors for poor clinical outcomes. Multivariate analysis identified PJK as the single independent risk factor (odds ratio [OR] = 3.957 for PJK development relative to no PJK, OR = 21.141 for revision surgery for PJK relative to no PJK). Conclusions: PJK development was the single independent factor affecting poor clinical outcomes in long-term follow-up. Therefore, PJK prevention appears crucial for achieving long-term success after ASD surgery.

Revisiting the diagnostic performance of exosomes: harnessing the feasibility of combinatorial exosomal miRNA profiles for colorectal cancer diagnosis.

The challenges associated with liquid biopsy of colorectal cancer (CRC) are closely linked to the substantial variations observed in gene expression profiles among patients. This variability complicates the selection of an ideal biomarker for accurate diagnosis. In this report, we propose that employing a combination of miRNAs offers a better change for enhancing the accuracy of CRC diagnosis compared to solely relying on single miRNAs. As an illustrative example, we measured 9 miRNAs from 45 patient samples (comprising 31 CRC cases and 14 healthy controls) via RT-qPCR. We then utilized two methods: (1) LASSO regression for marker ranking and (2) linear discriminant analysis (LDA) to identify the optimal weighted combination of multiple markers. Our data indicates that combination of triple markers, selected based on their ranking, exhibited the highest diagnostic performance, including a sensitivity of 93.6% (95% confidence interval, CI 79.3-98.9%), specificity of 100% (CI 78.5-100.0%), positive predictive value (PPV) of 100%, negative predictive value (NPV) of 87.5%, and an overall accuracy of 95.6%. In contrast, the diagnostic performance of each individual miRNA used in the triple marker combination ranged from 53.3 to 80.0% in accuracy. While we acknowledge the need for further extensive studies involving larger patient cohorts and the consideration of additional miRNA candidates, our research undeniably highlights the potential of combining multiple markers as a robust methodology for identifying biomarkers among heterogeneous patient profiles.

Survival and Prognostic Factors After Surgery in Single Spinal Metastasis: Comparison of Isolated-Single Spinal Metastasis and Single Spinal Metastasis With Other Metastasis.

STUDY DESIGN: Retrospective cohort study. OBJECTIVES: This study aimed to evaluate the survival period in patients with a single spinal metastasis (SSM), subsequently comparing those with isolated-single spinal metastasis (I-SSM) and single spinal metastasis with other metastasis (O-SSM) after surgery, and to identify prognostic factors affecting their survival. METHODS: A total of 135 patients were included, with 24 patients in the I-SSM group and 111 in the O-SSM group. Survival analysis was utilized to assess the survival of SSM patients, followed by a comparison of survival rates between the two groups. Univariate and multivariate analyses were conducted to identify significant prognostic factors for survival. RESULTS: The overall median survival period for patients with single spinal metastasis (SSM) was 10.2 ± 1.8 months. Specifically, the median survival was 15.7 ± 5.7 months in the I-SSM group and 10.2 ± 1.5 months in the O-SSM group. The difference in survival periods between the two groups was not statistically significant (P = 0.345). Significant independent prognostic factors for survival included preoperative Karnofsky Performance Status (KPS) of 50 - 70 (OR 0.51, P = 0.017) and 80 - 100 (OR 0.46, P = 0.012), postoperative ambulatory status (OR 1.19, P = 0.028), and primary malignancy site [Group B (OR 2.67, P = 0.021), Group C (OR 2.90, P = 0.016)]. CONCLUSIONS: Patients with SSM have a median survival of 10.2 months, with no significant difference in postoperative survival between the I-SSM and O-SSM groups. Significant prognostic factors influencing the survival period after surgery include preoperative KPS, postoperative ambulatory status, and the primary malignancy site.

Clinical and radiological comparisons between oblique lumbar interbody fusion combined with percutaneous pedicle screw fixation and transforaminal lumbar interbody fusion for adult isthmic spondylolisthesis: a 2-year follow-up study.

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.

Incidence and Risk Factors of Proximal Junctional Complications and Rod Fractures After Long-Segment Fusion Surgery With Anterior Column Realignment for Adult Spinal Deformity: A Minimum 2-Year Follow-Up.

BACKGROUND AND OBJECTIVES: To investigate the incidence and risk factors of proximal junctional kyphosis (PJK), proximal junctional failure (PJF), and rod fractures in patients undergoing long-segment (≥4 levels) fusion surgery with anterior column realignment (ACR) for adult spinal deformity. METHODS: Patients aged ≥60 years with at least a 2-year follow-up were grouped based on PJK, PJF, and rod fracture occurrence. Patient, surgical, and radiographic factors were compared to identify risk factors for these complications. Independent risk factors were identified using univariate and multivariate logistic regression. RESULTS: Among 106 patients, the incidence rates of PJK, PJF, and rod fractures were 15.1%, 28.3%, and 17.9%, respectively. PJK was significantly associated with fewer fusion levels (odds ratio [95% CI], 0.30 [0.13-0.69]), a cranially directed uppermost instrumented vertebra (UIV) screw angle (1.40 [1.13-1.72]), postoperative overcorrection of age-adjusted pelvic incidence-lumbar lordosis (LL) (7.22 [1.13-45.93]), and a large increase in thoracic kyphosis (1.09 [1.01-1.17]). PJF risks were associated with a cranial UIV screw orientation (1.23 [1.09-1.39]), overcorrection of age-adjusted pelvic incidence-LL (10.80 [2.55-45.73]), and a smaller change in sacral slope (0.87 [0.80-0.94]). For rod fractures, prominent factors included a greater number of fusion levels (1.70 [1.17-2.46]), a larger postoperative LL (1.07 [1.01-1.15]), a smaller postoperative thoracic kyphosis (0.92 [0.86-0.98]), and smaller changes in sacral slope (0.73 [0.58-0.92]) and pelvic tilt (0.72 [0.56-0.91]). CONCLUSION: The incidence and risk factors of PJK, PJF, and rod fractures were similar to those observed in previous studies on long-segment fusion surgery without ACR. The number of ACR levels was not a significant risk factor for PJK, PJF, or rod fractures. When performing deformity correction using ACR, surgeons should carefully consider the direction of the UIV screw and ensure that overcorrection is avoided.

Validation of Sagittal age-adjusted Score in Predicting Proximal Junctional Kyphosis/Failure and Clinical Outcomes Following Adult Spinal Deformity Surgery.

STUDY DESIGN: Retrospective study. OBJECTIVES: To validate the sagittal age-adjusted score (SAAS) in predicting proximal junctional kyphosis/failure (PJK/F) and good clinical outcomes following adult spinal deformity (ASD) surgery. SUMMARY OF BACKGROUND DATA: SAAS is a relatively new assessment system that incorporates age-adjusted sagittal parameters of pelvic incidence (PI) - lumbar lordosis (LL), pelvic tilt (PT), and T1 pelvic angle (TPA) to predict the PJK/F. External validation is required to verify its clinical usefulness. METHODS: We included patients with ASD undergoing ≥5-level fusion including the sacrum or pelvis. SAAS was calculated based on the scores of the three components: PI-LL, PT, and TPA. PJK/F rates and clinical outcomes were compared among the correction categories (undercorrection, matched correction, and overcorrection) for the SAAS as well as for each of the three components. PJK/F rates were compared according to the correction groups of the sagittal components and total SAAS using the chi-square test. Receiver operating characteristic (ROC) analysis was performed to evaluate the predictive ability of overcorrection to develop PJK/F for the three sagittal parameters and SAAS. PROMs at final follow-up were compared among correction groups using ANOVA with Bonferroni post-hoc corrections. RESULTS: A total 411 patients were included in the study (mean age: 69.3 y, mean body mass index: 25.9 kg/m2, total levels fused: 7.7 levels, and follow-up duration: 43.3 mo). Postoperative SAAS categories were as follow: undercorrection (13.4%), matched correction (30.2%), and overcorrection (56.4%). The PJK/F rates were significantly higher in the overcorrection group relative to PI-LL component (P=0.001) as well as SAAS (P=0.038) compared to undercorrection or matched correction groups. The clinical outcomes were best in patients who achieved matched correction relative to PI-LL component as well as SAAS compared to the other correction groups. However, the differentiating power of clinical outcomes across the correction categories was greater in the PI-LL component than in the SAAS. CONCLUSION: This study validated the efficacy of SAAS system to differentiate PJK/F development and good clinical outcomes. However, its differentiating power seems to be largely attributable to the function of the PI-LL component, as the PI-LL correction status better predicted PJK/F risk and clinical outcomes than SAAS.

Different Risk Factors between Bony and Ligamentous Proximal Junctional Failure in Patients Undergoing Thoracolumbar Fusion to Pelvis for Adult Spinal Deformity.

STUDY DESIGN: Retrospective study. OBJECTIVE: To analyze the risk factors for bony proximal junctional failure (B-PJF) and ligamentous PJF (L-PJF) separately after adult spinal deformity (ASD) surgery. SUMMARY OF BACKGROUND DATA: Despite numerous studies about the risk factors of PJF, it remains unclear whether same risk factors can be applied to both B-PJF and L-PJF. METHODS: Patients who underwent corrective surgery from low thoracic level (T9-T12) to pelvis with minimum follow-up duration of two years were included in this study. Patients with PJF were divided into two groups according to the involvement of bony structure: B-PJF and L-PJF. The control group was created using patients who did not develop PJF for ≥2 years postoperatively (no-PJF group). Risk factors were analyzed by comparing various clinical and radiographic parameters between no PJF versus B-PJF group and between no PJF versus L-PJF groups. RESULTS: The final study cohort comprised 240 patients. The mean age was 68.7 years, and there were 205 women (85.4%). On average, 8.1 levels were fused. PJF developed in 103 patients, with 70 (68.0%) in the B-PJF group and 33 (32.0%) in the L-PJF group. Stepwise logistic regression analyses revealed that older age (odds ratio [OR]=1.088), higher body mass index (BMI) (OR=1.161), osteoporosis (OR=3.293), greater postoperative lumbar distribution index (OR=1.032), and overcorrection relative to the age-adjusted pelvic incidence - lumbar lordosis (OR=3.964) were significant risk factors for B-PJF. Meanwhile, no use of transverse process (TP) hook was the single risk factor for L-PJF (OR=4.724). CONCLUSIONS: Understanding the difference in risk factors between B-PJF and L-PJF will facilitate the optimization of surgical outcome for patients with ASD. Appropriate correction of sagittal malalignment along with use of TP hook is advisable to mitigate both B-PJF and L-PJF development.

Incidence and Risk Factors for Mechanical Failure after Anterior Column Realignment in Adult Spinal Deformity Surgery.

STUDY DESIGN: Retrospective study. OBJECTIVES: To investigate the incidence and risk factors of mechanical failure (MF) following anterior column realignment (ACR) in patients with severe degenerative sagittal imbalance (DSI). SUMMARY OF BACKGROUND DATA: Considering the biomechanical properties of the procedure, ACR may increase the risk of MF, including proximal junctional kyphosis (PJK) and rod fracture (RF). However, this issue has been poorly documented in the literature. METHODS: We included patients aged ≥60 years with severe DSI radiographically defined by pelvic incidence (PI) - lumbar lordosis (LL) ≥20° undergoing ≥5-level fusion, including the sacrum. PJK was defined radiographically as a proximal junctional angle (PJA)>28° plus Δ PJA of>22°. RF was evaluated at ACR levels performed. Clinical and radiographic variables were compared to identify the risk factors for PJK and RF, then multivariate analysis was performed by combining PJK and RF into a single composite outcome of MF. RESULTS: We included a total of 147 patients in the final study cohort. The mean age was 70.3 years, and there were 126 women (90.6%). The median fusion length was 8 levels. After surgery, PI-LL was corrected from 48.1° to 4.3°. MF developed in 49 patients (33.3%); PJK in 41 (27.9%), RF in 11 (7.5%), and both PJK and RF in 3 (2.0%) patients. Multivariate analyses revealed that osteoporosis (odds ratio [OR]=2.361, 95% confidence interval [CI]=1.270 - 5.590, P=0.048) and an increased number of ACR levels (OR=1.762, 95% CI=1.039 - 3.587, P=0.036) were significant risk factors for MF. CONCLUSION: A considerable number of patients (33.3%) developed MF after deformity correction using ACR procedures. Therefore, appropriate surgical strategies are necessary to prevent MF in patients undergoing deformity correction using ACR, with special attention to the risk factors we identified here.

Risk Factors for Recurrent Proximal Junctional Failure Following Adult Spinal Deformity Surgery: Analysis of 60 Patients Undergoing Fusion Extension Surgery for Proximal Junctional Failure.

BACKGROUND: Despite numerous studies identifying risk factors for proximal junctional failure (PJF), risk factors for recurrent PJF (R-PJF) are still not well established. Therefore, we aimed to identify the risk factors for R-PJF following adult spinal deformity (ASD) surgery. METHODS: Among 479 patients who underwent ≥5-level fusion surgery for ASD, the focus was on those who experienced R-PJF at any time or did not experience R-PJF during a follow-up duration of ≥1 year. PJF was defined as a proximal junctional angle (PJA) ≥28° plus a difference in PJA ≥22° or performance of revision surgery regardless of PJA degree. The patients were divided into 2 groups according to R-PJF development: no R-PJF and R-PJF groups. Risk factors were evaluated focusing on patient, surgical, and radiographic factors at the index surgery as well as at the revision surgery. RESULTS: Of the 60 patients in the final study cohort, 24 (40%) experienced R-PJF. Significant risk factors included greater postoperative sagittal vertical axis (OR = 1.044), overcorrection relative to age-adjusted pelvic incidence-lumbar lordosis (PI-LL; OR = 7.794) at the index surgery, a greater total sum of the proximal junctional kyphosis severity scale (OR = 1.145), and no use of the upper instrumented vertebra cement (OR = 5.494) at the revision surgery. CONCLUSIONS: We revealed that the greater postoperative sagittal vertical axis and overcorrection relative to age-adjusted pelvic incidence-lumbar lordosis at the index surgery, a greater proximal junctional kyphosis severity scale score, and no use of upper instrumented vertebra cement at the revision surgery were significant risk factors for R-PJF. CLINICAL RELEVANCE: To reduce the risk of R-PJF after ASD surgery, avoiding under- and overcorrection during the initial surgery is recommended. Additionally, close assessment of the severity of PJF with timely intervention is crucial, and cement augmentation should be considered during revision surgery.

Different characteristics between acute and delayed proximal junctional failure in elderly patients undergoing corrective surgery for adult spinal deformity: comparative analysis of risk factor, failure mode, and clinical consequences.

BACKGROUND CONTEXT: While numerous studies have been conducted on proximal junctional failure (PJF), the clinical significance of acute and delayed PJF remains poorly understood. PURPOSE: The primary object of this study is to investigate the risk factors separately for acute and delayed PJF. Secondly, we aim to assess the incidence of each failure mode and their clinical consequences in relation to acute and delayed PJF. STUDY DESIGN/SETTING: Retrospective comparative study. PATIENT SAMPLE: Patients aged ≥60 years who underwent deformity correction with ≥5-level fusion to sacrum. OUTCOME MEASURES: Risk factor, failure modes, and patient-reported outcome measure (PROM). METHODS: Acute PJF is defined as PJF occurring within 6 months, while delayed PJF occurring after 6 months. Risk factors were analyzed by comparing various clinical and radiographic parameters among 3 groups: no, acute, and delayed PJF groups. The failure modes, including soft tissue failure, vertebral fracture, fixation failure, and myelopathy, were compared among these groups. The clinical subsequences after PJF development were evaluated by assessing the change in proximal junctional angle (PJA), revision rate, and patient-reported outcome measure (PROM). RESULTS: A study cohort of 363 patients was included in the analysis. Among them, 156 patients experienced PJF, with 87 patients (55.8%) in the acute PJF group and 69 patients (44.2%) in the delayed PJF group. Multivariate analyses showed that older age (Odds ratio [OR] = 1.057, 95% confidence interval [CI] = 1.002-1.118), osteoporosis (OR=2.149, 95% CI = 1.074-4.300), high American Society of Anesthesiology ASA score (OR=2.150, 95% CI = 1.089-4.245), and overcorrection relative to the age-adjusted pelvic incidence - lumbar lordosis target (OR=4.031, 95% CI = 1.962-8.280) were identified as risk factors for the development of acute PJF. On the other hand, a high body mass index (OR=1.150, 95% CI = 1.049-1.251) and an uppermost instrumented vertebra located at ≤T10 (OR=2.267, 95% CI = 1.205-4.268) were found to be associated with delayed occurrence of PJF. No radiographic parameters were found to be related to the development of delayed PJF. In terms of failure modes, vertebral fracture and fixation failure were more commonly observed in acute PJF, while soft tissue failure and myelopathy were more predominant in delayed PJF. The clinical course was more aggressive in the acute PJF group compared to the delayed PJF group, as evidenced by a greater increase in PJA, a higher revision rate, and worse PROM. CONCLUSIONS: This study demonstrated different risk factors between the acute and delayed PJF. It was found that overcorrection relative to the age-adjusted PI-LL target increased the risk of acute PJF, but had no impact on the development of delayed PJF. Therefore, a different surgical strategy needs to be established to mitigate both acute and delayed PJF.

Comparison of Surgical Burden, Radiographic and Clinical Outcomes According to the Severity of Baseline Sagittal Imbalance in Adult Spinal Deformity Patients.

OBJECTIVE: To determine the clinical impact of the baseline sagittal imbalance severity in patients with adult spinal deformity (ASD). METHODS: We retrospectively reviewed patients who underwent ≥ 5-level fusion including the pelvis, for ASD with a ≥ 2-year follow-up. Using the Scoliosis Research Society-Schwab classification system, patients were classified into 3 groups according to the severity of the preoperative sagittal imbalance: mild, moderate, and severe. Postoperative clinical and radiographic results were compared among the 3 groups. RESULTS: A total of 259 patients were finally included. There were 42, 62, and 155 patients in the mild, moderate, and severe groups, respectively. The perioperative surgical burden was greatest in the severe group. Postoperatively, this group also showed the largest pelvic incidence minus lumbar lordosis mismatch, suggesting a tendency towards undercorrection. No statistically significant differences were observed in proximal junctional kyphosis, proximal junctional failure, or rod fractures among the groups. Visual analogue scale for back pain and Scoliosis Research Society-22 scores were similar across groups. However, severe group's last follow-up Oswestry Disability Index (ODI) scores significantly lower than those of the severe group. CONCLUSION: Patients with severe sagittal imbalance were treated with more invasive surgical methods along with increased the perioperative surgical burden. All patients exhibited significant radiological and clinical improvements after surgery. However, regarding ODI, the severe group demonstrated slightly worse clinical outcomes than the other groups, probably due to relatively higher proportion of undercorrection. Therefore, more rigorous correction is necessary to achieve optimal sagittal alignment specifically in patients with severe baseline sagittal imbalance.

The Optimal Lowest Instrumented Vertebra to Prevent the Distal Adding-On Phenomenon in Patients Undergoing Selective Thoracic Fusion for Adolescent Idiopathic Scoliosis with Lenke Type 1A and 1B Curves: Comparison of Nine Selection Criteria.

Background/Objectives: There is no solid consensus regarding which lowest instrumented vertebra (LIV) selection criterion is best to prevent distal adding-on (DA) after adolescent idiopathic scoliosis (AIS) surgery. This study aims to search out the LIV selection criteria in the literature and to compare the ability of each LIV selection criterion to prevent DA in patients with AIS. Methods: Patients who underwent thoracic fusion for AIS of Lenke type 1A or 1B were included in this study. Nine criteria for LIV selection were found in a literature review. For each patient, whether the postoperative actual location of LIV was met with the suggested locations of the LIV was assessed. The preventive ability of nine criteria against DA was evaluated using logistic regression analysis. The patients who met the LIV selection criteria but developed DA were investigated. Results: The study cohort consisted of 145 consecutive patients with a mean age of 14.8 years. The criteria of Suk (OR = 0.267), Parisini (OR = 0.230), Wang (OR = 0.289), and Qin (OR = 0.210) showed a significantly decreased risk of DA if the LIV selection criterion was chosen at each suggested landmark. As the additional levels were fused, there was no statistically significant benefit in further reducing the risk of DA. Among the patients who met each criterion, the incidence of DA was lower in criteria by Takahashi (5.9%), Qin (7.1%), and King (7.4%) than the others. Conclusions: Qin's criterion, using the substantially touching vertebra concept, has the highest preventive ability against DA development. Extending the instrumentation further distal to this suggested LIV criterion did not add further benefit.

Are Surgical Outcomes Different According to Baseline Balance Status in Elderly Patients with Degenerative Sagittal Imbalance?

STUDY DESIGN: Retrospective study. OBJECTIVE: We sought to compare surgical outcomes according to baseline balance statuses in elderly patients with degenerative sagittal imbalance (DSI). SUMMARY OF BACKGROUND: Although optimal sagittal correction has been emphasized for good surgical outcomes, the effect of the state of preoperative balance on surgical outcome has been adequately described at present. METHODS: Patients aged ≥60 years with DSI who underwent ≥5-level fusion to the sacrum were included. Among them, only those who postoperatively achieved the optimal age-adjusted pelvic incidence (PI) - lumbar lordosis (LL) target were included in this study. Study participants were divided into two groups according to their preoperative sagittal vertical axis (SVA): compensatory balance (SVA <5 cm, group CB) and decompensation (SVA ≥5 cm, group D). Comparisons between the two groups were performed using the chi-squared test or Fisher's exact test for categorical variables and the independent t- test or Wilcoxon rank- sum test for continuous variables. RESULTS: A total of 156 patients whose postoperative sagittal alignment matched the age-adjusted PI-LL target constituted the study cohort. There were 59 patients in group CB and 97 patients in group D. Mean follow-up duration was 50.0 months after surgery. Immediate postoperatively, sacral slope and SVA were significantly greater in group D than in group CB. At last follow-up, the SVA was significantly greater in group D than in group CB (43.6 vs. 22.7 mm), while no significant differences were found in other sagittal parameters. The Oswestry disability index and Scoliosis Research Society -22 scores at the last follow-up were significantly worse in group D than in group CB. CONCLUSION: The SVA tended to experience less correction postoperatively, with evidence of further deterioration during follow-up in group D than in group CB. This suboptimal correction of SVA may contribute to the inferior clinical outcomes encountered in group D relative to group CB. Therefore, we recommend correction of PI-LL as close as possible to the lower limit of the suggested PI-LL target range in patients with evidence of preoperative decompensation.

Reliability and Validity of the Korean version of the Center for Neurologic Study Bulbar Function Scale (K-CNS-BFS): An observational study.

Bulbar dysfunction in amyotrophic lateral sclerosis (ALS) significantly affects daily life, leading to weight loss and reduced survival. Methods for evaluating bulbar dysfunction, including videofluoroscopic swallowing studies and the bulbar component of the ALS Functional Rating Scale-Revised (ALSFRS-R), have been employed; however, Korean-specific tools are lacking. The Center for Neurologic Study Bulbar Function Scale (CNS-BFS) comprehensively evaluates bulbar symptoms. This study aimed to develop and validate the Korean version of the CNS-BFS (K-CNS-BFS) to assess bulbar dysfunction in Korean patients with ALS. Twenty-seven patients with ALS were recruited from a tertiary hospital in South Korea based on revised El Escorial criteria. Demographic, clinical, and measurement data were collected. The K-CNS-BFS was evaluated for reliability and validity. Reliability assessment revealed strong internal consistency (Cronbach alpha) for the K-CNS-BFS subscales and total score. Test-retest reliability showed significant correlation. Content validity index was excellent, and convergent validity demonstrated significant correlations between the K-CNS-BFS and relevant measures. Discriminant validity was observed between the K-CNS-BFS and motor/respiratory subscores of the ALSFRS-R. Construct validity demonstrated significant correlations between the K-CNS-BFS subscales and total score. This is the first study to investigate the reliability and validity of the Korean version of the CNS-BFS, which showed consistent and reliable scores that correlated with tests for bulbar or general dysfunction. The K-CNS-BFS effectively measured bulbar dysfunction similar to the original CNS-BFS. The K-CNS-BFS is a reliable and valid tool for assessing bulbar dysfunction in patients with ALS in South Korea.

Ideal Lumbar Lordosis Correction in Patients with Adult Spinal Deformity Without Adversely Impacting Pelvic Tilt and Pelvic Incidence Minus Lumbar Lordosis: A Study of 426 Cases.

STUDY DESIGN: Retrospective study. OBJECTIVES: To determine the ideal pelvic incidence (PI) - lumbar lordosis (LL) range to prevent pelvic tilt (PT) undercorrection while avoiding PI-LL overcorrection following adult spinal deformity (ASD) surgery. SUMMARY OF BACKGROUND: PI-LL and PT are the important sagittal parameters to be restored to an adequate range by surgery. Ideal PI-LL target without causing PI-LL overcorrection and PT undercorrection has not been documented. METHODS: We included patients with ASD undergoing ≥5-level fusion including the sacrum. Receiver operating characteristic (ROC) curve analysis was performed to calculate the lower limit of the ideal PI-LL without causing PI-LL overcorrection and the upper limit of ideal PI-LL without causing PT undercorrection. The calculated ideal PI-LL was validated in terms of proximal junctional kyphosis and failure (PJK and PJF) rates and clinical outcomes. Analyses were performed according to age subgroups (<70 and ≥70 y). RESULTS: In total, 426 patients were included in the study. Female patients were predominant (85.4%), with a mean age of 69.8 years. The lower limits of PI-LL were calculated as 4.9° for all patients, 2.3° for patients aged <70 years, and 7.9° for patients aged ≥70 years. Meanwhile, the upper limits of PI-LL were calculated as 12.7° for all patients, 12.5° for patients aged <70 years, and 13.3° for patients aged ≥70 years. There were no significant differences in the PJK and PJF rates among the new three PI-LL groups. Clinical outcomes were significantly better in patients with the ideal PI-LL group than those in patients with overcorrection or undercorrection groups for all age groups. CONCLUSION: The ideal PI-LL correction target without adversely impacting PT and PI-LL was calculated at 2.3°-12.5° for patients aged <70 years and 7.9°-13.3° for patients aged ≥70 years. These guideline parameters may help ensure optimal clinical outcomes without increasing the risk of PJK/F.

Hook Fixation at Uppermost Instrumented Vertebra +1 Reduced Proximal Junctional Failure in Adult Patients With Spinal Deformity Having Achieved Optimal Deformity Correction by Sagittal Age-Adjusted Score.

BACKGROUND AND OBJECTIVES: Appropriate correction relative to the age-adjusted sagittal alignment target reduces the proximal junctional failure (PJF) risk. Nonetheless, a considerable number of patients suffer from PJF despite optimal correction. The aim of this study was to identify the risk factors of PJF that occurs despite optimal correction relative to the sagittal age-adjusted score (SAAS) in adult spinal deformity surgery. METHODS: Patients aged 60 years or older with adult spinal deformity who underwent ≥5-level fusion to the sacrum were initially screened. Among them, only patients who achieved optimal sagittal correction relative to the SAAS were included in the study. Optimal correction was defined as the SAAS point between -1 and +1. Various clinical and radiographic factors were compared between the PJF and no PJF groups and were further evaluated using multivariate analysis. RESULTS: The final study cohort comprised 127 patients. The mean age was 67 years, and there were 111 women (87.4%). A mean of total fusion length was 7.2. PJF occurred in 42 patients (33.1%), while 85 patients (66.9%) did not develop PJF. Multivariate analysis showed that a high body mass index (odds ratio [OR] = 1.153, 95% CI = 1.027-1.295, P = .016), a higher lordosis distribution index (LDI) (OR = 1.024, 95% CI = 1.003-1.045, P = .022), and no use of hook fixation (OR = 9.708, 95% CI = 1.121-76.923, P = .032) were significant risk factors of PJF development. In the receiver operating characteristic curve analysis, the cutoff value for the LDI was calculated as 61.0% (area under the curve = 0.790, P < .001). CONCLUSION: PJF developed in a considerable portion of patients despite optimal correction relative to the age-adjusted alignment. The risk factors of PJF in this patient group were high body mass index, high LDI exceeding 61%, and no use of hook fixation. PJF could be further decreased by properly managing these risk factors along with optimal sagittal correction.

Outcomes of Hybrid Total Hip Arthroplasty for Subchondral Insufficiency Fracture of the Femoral Head.

Background: The purpose of this study was to evaluate functional outcomes, radiologic results, and complications after hybrid total hip arthroplasty (THA) in patients with subchondral insufficiency fractures (SIFs) of the femoral head. Methods: From June 2009 to December 2020, among 985 patients who underwent hybrid THA at our hospital, 19 patients diagnosed with SIF through a retrospective chart review were included. Those under 50 years of age, with radiographic findings of osteonecrosis on the contralateral side of surgery, a history of organ transplantation, and alcohol abuse, were excluded. Functional evaluation was performed using a modified Harris Hip Score (HHS). After surgery, inclination and anteversion of the acetabular cup and version of the femoral system were measured using postoperative x-ray. The outpatient follow-up was performed at 6 weeks, 3 months, 9 months, and 12 months after surgery and every year thereafter. Complications including dislocation, implant loosening, stem subsidence, and periprosthetic infection were observed on follow-up radiographs. Results: The average follow-up time was 29.3 ± 9.1 months (range, 24-64 months) with no loss to follow-up. The mean modified HHS was 83.4 ± 9.6 (range, 65-100) at the last outpatient clinic follow-up. The average inclination of the acetabular cup was 41.9° ± 3.4° (range, 37°-48°), and the anteversion was 27.5° ± 6.7° (range, 18°-39°). The version of the femoral stem was 19° ± 5.7° (range, 12°-29°). There was no case of intraoperative fracture. There were no cases of dislocation, loosening of the cup, subsidence of the femoral stem, intraoperative or periprosthetic fracture, or periprosthetic infection on the follow-up radiographs. Conclusions: In our study, hybrid THA showed favorable outcomes in patients diagnosed with SIF, and there were no further special considerations as for THA performed due to other diseases or fractures.

Impact of COVID-19 Infection and Its Association With Previous Vaccination in Patients With Myasthenia Gravis in Korea: A Multicenter Retrospective Study.

BACKGROUND: During the coronavirus disease 2019 (COVID-19) pandemic, patients with myasthenia gravis (MG) were more susceptible to poor outcomes owing to respiratory muscle weakness and immunotherapy. Several studies conducted in the early stages of the COVID-19 pandemic reported higher mortality in patients with MG compared to the general population. This study aimed to investigate the clinical course and prognosis of COVID-19 in patients with MG and to compare these parameters between vaccinated and unvaccinated patients in South Korea. METHODS: This multicenter, retrospective study, which was conducted at 14 tertiary hospitals in South Korea, reviewed the medical records and identified MG patients who contracted COVID-19 between February 2022 and April 2022. The demographic and clinical characteristics associated with MG and vaccination status were collected. The clinical outcomes of COVID-19 infection and MG were investigated and compared between the vaccinated and unvaccinated patients. RESULTS: Ninety-two patients with MG contracted COVID-19 during the study. Nine (9.8%) patients required hospitalization, 4 (4.3%) of whom were admitted to the intensive care unit. Seventy-five of 92 patients were vaccinated before contracting COVID-19 infection, and 17 were not. During the COVID-19 infection, 6 of 17 (35.3%) unvaccinated patients were hospitalized, whereas 3 of 75 (4.0%) vaccinated patients were hospitalized (P < 0.001). The frequencies of ICU admission and mechanical ventilation were significantly lower in the vaccinated patients than in the unvaccinated patients (P = 0.019 and P = 0.032, respectively). The rate of MG deterioration was significantly lower in the vaccinated patients than in the unvaccinated patients (P = 0.041). Logistic regression after weighting revealed that the risk of hospitalization and MG deterioration after COVID-19 infection was significantly lower in the vaccinated patients than in the unvaccinated patients. CONCLUSION: This study suggests that the clinical course and prognosis of patients with MG who contracted COVID-19 during the dominance of the omicron variant of COVID-19 may be milder than those at the early phase of the COVID-19 pandemic when vaccination was unavailable. Vaccination may reduce the morbidity of COVID-19 in patients with MG and effectively prevent MG deterioration induced by COVID-19 infection.