The Spinopelvic Alignment in Patients with Prior Knee or Hip Arthroplasty Undergoing Elective Lumbar Surgery.

BACKGROUND CONTEXT: Concurrent degeneration of the lumbar spine, hip, and knee can cause significant disability and lower quality of life. Osteoarthritis in the lower extremities can lead to movement limitations, possibly requiring total knee arthroplasty (TKA) or total hip arthroplasty (THA). These procedures often impact spinal posture, causing alterations in spinopelvic alignment and lumbar spine degeneration. It is unclear if patients with a history of prior total joint arthroplasty (TJA) have different spinopelvic alignment compared to patients without. PURPOSE: To assess the relationship between a history of previous THA or TKA, as well as combined THA and TKA, and the spinopelvic alignment in patients undergoing elective lumbar surgery for degenerative conditions. STUDY DESIGN: A retrospective analysis was conducted on patients who underwent lumbar surgery for degenerative conditions. The patients were stratified based on a history of TKA, THA, or both TKA and THA. PATIENT SAMPLE: A total of 632 patients (63% female) with an average age of 64 ± 11 years and an average BMI of 30 ± 6 kg/m2 were included. OUTCOME MEASURES: Patients were stratified based on a history of THA, TKA, or combined THA and TKA. Spinopelvic parameters (lumbar lordosis (LL), sacral slope (SS), pelvic tilt (PT), and pelvic incidence (PI)) were assessed. The relationship between spinopelvic alignment and prior TKA, THA or TKA and THA was analyzed METHODS: The data was tested for normal distribution using the Shapiro-Wilk test. We analyzed the relationship between the spinopelvic parameters and the different arthroplasty groups. Differences in scores between groups were examined using ANOVA. Tukey's Honestly Significant Difference test was used for pairwise comparison for significant ANOVA test results. Multivariable linear regression was applied, adjusted for age, sex and BMI. RESULTS: A total of 632 patients (63% female) were included in the study. Of these patients, 74 (12%) had a history of isolated TKA, 40 (6%) had prior isolated THA, and 15 (2%) had TKA and THA prior to lumbar surgery. Patients with prior arthroplasty were predominantly female (59%) and significantly older (68 ± 7 years vs. 63 ± 12 years, p<0.001) with a significantly higher BMI (31 ± 6 kg/m2 vs. 29 ± 6 kg/m2, p<0.001). The LL was significantly lower (45.0° ± 13 vs. 50.9° ± 14 p=0.011) in the arthroplasty group compared to the non-arthroplasty group. A history of isolated TKA was significantly associated with lower LL (Est= -3.8, 95% CI -7.3 to -0.3, p=0.031) and SS (Est= -2.6, 95% CI -5.0 to -0.2, p=0.012) compared to patients without TJA. Prior combined THA and TKA was found to be significantly associated with a higher PT compared to the non-arthroplasty group (Est= 5.1, 95% CI 0.4-9.8, p=0.034). CONCLUSION: The spinopelvic alignment differs between patients with and without prior TJA who undergo elective lumbar surgery. The study shows that a history of TKA is significantly associated with a lower LL and SS. The combination of THA and TKA was associated with a significantly higher PT. These findings highlight the complex relationship between the hip, spine, and knee. Moreover, the results could aid in enhancing preoperative planning of lumbar surgery in patients with known TJA.

The Disaggregation of the Oswestry Disability Index in Patients undergoing Lumbar Surgery for Degenerative Lumbar Spondylolisthesis.

BACKGROUND CONTEXT: The Oswestry Disability Index (ODI), is a widely used patient-reported outcome measure (PROM) for assessing functional status in individuals with lumbar spine pathology. The ODI is used by surgeons to determine the initial status and monitor progress after surgery. Compiled ODI data enables comparisons between different surgical techniques. Degenerative lumbar spondylolisthesis (DLS) often causes symptoms such as back pain and neurogenic claudication affecting quality of life and activities of daily living captured by the ODI. Despite extensive studies on ODI changes after spinal surgery, little is known about the characteristics and changes in the different ODI subsections. PURPOSE: To analyze the baseline characteristics and changes in total ODI and ODI subsections 2 years after elective lumbar surgery. STUDY DESIGN: Retrospective analysis on patients prospectively enrolled who underwent spinal surgery for degenerative lumbar spondylolisthesis from 2016 to 2018. The ODI was assessed preoperatively and 2 years postoperatively. PATIENT SAMPLE: A total of 265 patients were included in the study, 60% were female. The mean age of the patients was 67 ± 8 years, and the mean BMI was 30 ± 6 kg/m2. OUTCOME MEASURES: The analysis considered the differences in ODI scores before and after surgery, as well as the changes in all ODI subsections 2 years after elective lumbar surgery for DLS. METHODS: The analysis evaluated differences in ODI scores and variations in different subsections. Patients without an ODI follow-up at 2 years were excluded from the study. The study utilized the Wilcoxon Signed Rank Test for all pre-post paired samples. The Wilcoxon rank sum test was used for sex and procedure comparisons for overall ODI and ODI subsection analysis. Univariate linear regression was applied for overall and subsection specific ODI outcomes with age and BMI as independent variables, respectively. The statistical significance level was set at p<0.05. RESULTS: Improvement in ODI was observed in 242 patients (91%). The highest baseline disability values were found for the questions regarding pain intensity (3.4 ± 1.3), lifting (3.2 ± 1.9), and standing (3.4 ± 1.3). The lowest preoperative functional limitations were observed in sleeping (1.6 ± 1.3), personal care (1.6 ± 1.4), traveling (1.6 ± 1.2) and sitting (1.5 ± 1.4). At the 2-year follow-up, there was significant improvement in all questions and the overall ODI (all p<0.001). The ODI subsections that showed the greatest absolute improvements were changing degree of pain (-2.6), with 89% of patients experiencing improvement, standing (-2.4) with 87% of patients experiencing improvement, and pain intensity (-2.1) with 81% of patients experiencing improvement. The subsections with the least improvement were personal care (-0.6), sitting (-0.7), and sleeping (-0.9). The study found that female patients had a significantly higher preoperative disability in various subsections but showed greater improvement in total ODI compared to male patients (p=0.001). Additionally, improvement in sitting (p<0.001), traveling (p<0.001), social life (p<0.001) and sleeping (p=0.018) were significantly higher in female patients. Older patients showed significantly less improvement in sitting (p=0.005) and sleeping (p=0.002). A higher BMI was significantly associated with less improvement in changing degree of pain (p=0.025) and higher baseline disability in various subsections. Patients who underwent decompression and fusion had significantly higher baseline disability in several subsections compared to those who underwent decompression alone. There was no significant difference between decompression alone and decompression with fusion in terms of overall improvement in the ODI and improvement in the subsections. CONCLUSION: These results offer a more comprehensive understanding of ODI and its changes across different subsections. This insight is invaluable for improving preoperative education and effectively managing patient expectations regarding potential post-surgery disability in specific areas.

The Association between prior arthroplasty and Paraspinal Muscle Degeneration in patients undergoing elective lumbar surgery.

PURPOSE: Spinal and lower extremity degeneration often causes pain and disability. Lower extremity osteoarthritis, eventually leading to total knee- (TKA) and -hip arthroplasty (THA), can alter posture through compensatory mechanisms, potentially causing spinal misalignment and paraspinal muscle (PM) atrophy. This study aims to evaluate the association between prior THA or TKA and PM-degeneration in patients undergoing elective lumbar surgery for degenerative conditions. METHODS: A retrospective analysis of patients undergoing lumbar surgery for degenerative conditions was conducted. Patients were categorized based on prior THA, TKA, or both. Quantitative analysis of functional cross-sectional area (fCSA) and fat infiltration (FI) of psoas, multifidus (MF), and erector spinae (ES) muscles at L4-level was performed using T2-weighted MRI images. The association between the FI and fCSA of the PM and prior arthroplasty was investigated. Differences were assessed using ANOVA and multivariable linear regression. RESULTS: Overall, 584 patients (60% female, 64 ± 12 years) were included. 66 patients (11%) had prior TKA, 36 patients (6%) THA, and 15 patients (3%) both TKA and THA. Patients with arthroplasty were mostly female (57%) and notably older (p < 0.001). The FI of the MF and the ES was significantly higher in the arthroplasty-group (both p < 0.001). Patients with prior TKA showed significantly higher FI (Est = 4.3%, p = 0.013) and lower fCSA (Est=-0.9 cm2, p = 0.012) in the MF compared to the non-arthroplasty-group. CONCLUSION: This study demonstrates a significant lower fCSA and higher FI in the MF among individuals with prior TKA. This highlights the complex knee-spine relationship and how these structures interact with each other.

Differences at Index Surgery in Operative Complexity and Residual Disease for Earlier and Later Repeat Lumbar Surgery.

STUDY DESIGN: Retrospective review, single-institution cohort studies. OBJECTIVE: To compare patients with earlier (i.e. <1.5 y) and later (i.e. >1.5 y) repeat lumbar surgery to patients with no repeat surgery according to clinical characteristics at index surgery. BACKGROUND: Grouping patients as earlier or later repeat surgery may reveal different associations when compared to patients with no repeat surgery. METHODS: Patients undergoing index surgery for diverse conditions reported preoperative demographic/clinical variables, including comorbidity and depressive symptoms. Extent (i.e. complexity) of surgery was assigned based on a valid index that included decompression, fusion and instrumentation. Co-existing disease at non-operated levels was ascertained from imaging reports. Postoperative records of all medical visits up to the time of this study (12 y) were reviewed for repeat surgery. Patients were grouped as earlier (<1.5 y) or later surgery (≥1.5 y) and compared to patients with no repeat surgery in separate multivariable analyses. RESULTS: Among 1,334 patients (51% men, mean age 59), 82% did not have repeat surgery, 7% had earlier and 11% had later repeat surgery. Compared to no surgery, earlier surgery was associated with more comorbidity (OR 1.7, CI 1.1-2.6, P=0.02), positive depression screen (OR 1.9, CI 1.2-2.9, P=0.006), opioid use (OR 1.8, CI 1.2-2.8, P=0.008), and greater extent of index surgery (OR 1.1, CI 1.0-1.1, P=0.0009). Compared to no surgery, later surgery was associated with pre-index lumbar surgery (OR 1.9, CI 1.3-2.8, P=0.0005) and disease at non-operated levels at index surgery (OR 1.6, CI 1.0-2.4, P=0.05). Earlier surgeries were more likely to involve only the same vertebra as index surgery (51% vs. 16%) and later surgeries were more likely to involve only other levels (5% vs. 36%, P=0.01). CONCLUSIONS: Earlier and later repeat lumbar surgeries differed in complexity and residual disease compared to no repeat surgery. These findings have implications for patient counseling regarding short and long-term postoperative spine health.

Associations between surgeons' preoperative expectations of lumbar surgery and patient-reported 2-year outcomes.

PURPOSE: Surgeons' preoperative expectations of lumbar surgery may be associated with patient-reported postoperative outcomes. METHODS: Preoperatively spine surgeons completed a validated Expectations Survey for each patient estimating amount of improvement expected (range 0-100). Preoperative variables were clinical characteristics, spine-specific disability (ODI), and general health (RAND-12). Two years postoperatively patients again completed these measures and global assessments of satisfaction. Surgeons' expectations were compared to preoperative variables and to clinically important pre- to postoperative changes (MCID) in ODI, RAND-12, and pain and to satisfaction using hierarchical models. RESULTS: Mean expectations survey score for 402 patients was a 57 (IQR 44-68) reflecting moderate expectations. Lower scores were associated with preoperative older age, abnormal gait, sensation loss, vacuum phenomena, foraminal stenosis, prior surgery, and current surgery to more vertebrae (all p ≤ .05). Lower scores were associated postoperatively with not attaining MCID for the ODI (p = .02), RAND-12 (p = .01), and leg pain (p = .01). There were no associations between surgeons' scores and satisfaction (p = .06-.27). 55 patients (14%) reported unfavorable global outcomes and were more likely to have had fracture/infection/repeat surgery (OR 3.2, CI 1.6-6.7, p = .002). CONCLUSION: Surgeons' preoperative expectations were associated with patient-reported postoperative improvement in symptoms and function, but not with satisfaction. These findings are consistent with clinical practice in that surgeons expect some but not complete improvement from surgery and do not anticipate that any particular patient will have markedly unfavorable satisfaction ratings. In addition to preoperative discussions about expectations, patients and surgeons should acknowledge different types of outcomes and address them jointly in postoperative discussions.

What is the Association of the Subsections of the Oswestry Disability Index and Overall Improvement Two Years after Lumbar Surgery for Degenerative Lumbar Spondylolisthesis?

STUDY DESIGN: Retrospective review of a prospective cohort study. OBJECTIVE: To identify the association between Oswestry Disability Index (ODI) subsections and overall improvement 2 years after lumbar surgery for degenerative lumbar spondylolisthesis (DLS). BACKGROUND: DLS often necessitates lumbar surgery. The ODI is a trusted measure for patient-reported outcomes (PROMs) in assessing spinal disorder outcomes. Surgeons utilize the ODI for baseline functional assessment and post-surgery progress tracking. However, it remains uncertain if and how each subsection influences overall ODI improvement. METHODS: This retrospective cohort study analyzed patients who underwent lumbar surgery for DLS between 2016 and 2018. Preoperative and 2-year postoperative ODI assessments were conducted. The study analyzed postoperative subsection scores and defined ODI improvement as ODIpreop-ODIpostop >0. Univariate linear regression was applied, and receiver operating characteristic (ROC) analysis determined cut-offs for subsection changes and postoperative target values to achieve overall ODI improvement. RESULTS: 265 patients (60% female, mean age 67±8 y) with a baseline ODI of 50±6 and a postoperative ODI of 20±7 were included. ODI improvement was noted in 91% (242 patients). Achieving a postoperative target score of ≤2 in subsections correlated with overall ODI improvement. Walking had the highest predictive value for overall ODI improvement (AUC 0.91, sensitivity 79%, specificity 91%). Pain intensity (AUC 0.90, sensitivity 86%, specificity 83%) and changing degree of pain (AUC 0.87, sensitivity 86%, specificity 74%) were also highly predictive. Sleeping had the lowest predictability (AUC 0.79, sensitivity 84%, specificity 65%). Except for sleeping, all subsections had a Youden-index >50%. CONCLUSION: These findings demonstrate how the different ODI subsections associate with overall improvement post-lumbar surgery for DLS. This understanding is crucial for refining preoperative education, addressing particular disabilities, and evaluating surgical efficacy. Additionally, it shows that surgical treatment does not affect all subsections equally.

How much improvement in Oswestry Disability Index is Necessary to make your Patient Satisfied after Lumbar Surgery?

STUDY DESIGN: Retrospective review of cohort studies. OBJECTIVE: To clarify the necessary ODI improvement for patient satisfaction two years after lumbar surgery. BACKGROUND: Evaluating elective lumbar surgery care often involves patient-reported outcomes (PRO). While postoperative functional improvement measured by ODI is theoretically linked to satisfaction, conflicting evidence exists regarding this association. METHODS: Baseline ODI and 2-year postoperative ODI were assessed. Patient satisfaction, measured on a scale from 1 to 5, with scores ≥4 considered satisfactory, was evaluated. Patients with incomplete follow-up were excluded. Statistical analyses included Mann-Whitney-U and multivariable logistic regression adjusted for age, sex, and BMI. Receiver operating characteristic (ROC) analysis determined threshold values for ODI improvement and postoperative target ODI indicative of patient satisfaction. RESULTS: 383 patients were included (mean age 65±10 y, 57% female). ODI improvement was observed in 91% of patients, with 77% reporting satisfaction scores ≥4. Baseline ODI (median 62, IQR 46-74) improved to a median of 10 (IQR 1-10) 2 years postoperatively. Baseline (OR 0.98, P=0.015) and postoperative ODI scores (OR 0.93, P<0.001), as well as the difference between them (OR 1.04, P< 0.001), were significantly associated with patient satisfaction. Improvement of ≥38 ODI points or a relative change of ≥66% was indicative for patient satisfaction, with higher sensitivity (80%) and specificity (82%) for the relative change versus the absolute change (69%, 68%). With a sensitivity of 85% and a specificity of 77%, a postoperative target ODI of ≤24 indicated patient satisfaction. CONCLUSION: Lower baseline ODI and greater improvements in postoperative ODI are associated with an increased likelihood of patient satisfaction. A relative improvement of ≥66% or achieving a postoperative ODI score of ≤24 were the most indicative thresholds for predicting patient satisfaction, proving more sensitivity and specificity than an absolute change of ≥38 points.

The relationship between paraspinal muscle atrophy and degenerative lumbar spondylolisthesis at the L4/5 level.

BACKGROUND/CONTEXT: Degenerative lumbar spondylolisthesis (DLS) is a prevalent spinal condition that can result in significant disability. DLS is thought to result from a combination of disc and facet joint degeneration, as well as various biological, biomechanical, and behavioral factors. One hypothesis is the progressive degeneration of segmental stabilizers, notably the paraspinal muscles, contributes to a vicious cycle of increasing slippage. PURPOSE: To examine the correlation between paraspinal muscle status on MRI and severity of slippage in patients with symptomatic DLS. STUDY DESIGN/SETTING: Retrospective cross-sectional study at an academic tertiary care center. PATIENT SAMPLE: Patients who underwent surgery for DLS at the L4/5 level between 2016-2018 were included. Those with multilevel DLS or insufficient imaging were excluded. OUTCOME MEASURES: The percentage of relative slippage (RS) at the L4/5 level evaluated on standing lateral radiographs. Muscle morphology measurements including functional cross-sectional area (fCSA), body height normalized functional cross-sectional area (HI) of Psoas, erector spinae (ES) and multifidus muscle (MF) and fatty infiltration (FI) of ES and MF were measured on axial MR. Disc degeneration and facet joint arthritis were classified according to Pfirrmann and Weishaupt, respectively. METHODS: Descriptive and comparative statistics, univariable and multivariable linear regression models were utilized to examine the associations between RS and muscle parameters, adjusting for confounders sex, age, BMI, segmental degeneration, and back pain severity and symptom duration. RESULTS: The study analyzed 138 out of 183 patients screened for eligibility. The median age of all patients was 69.5 years (IQR 62 to 73), average BMI was 29.1 (SD±5.1) and average preoperative ODI was 46.4 (SD±16.3). Patients with Meyerding-Grade 2 (M2, N=25) exhibited higher Pfirrmann scores, lower MFfCSA and MFHI, and lower BMI, but significantly more fatty infiltration in the MF and ES muscles compared to those with Meyerding Grade 1 (M1). Univariable linear regression showed that each cm2 decrease in MFfCSA was associated with a 0.9%-point increase in RS (95% CI -1.4 to - 0.4, p<.001), and each cm2/m2 decrease in MFHI was associated with an increase in slippage by 2.2%-points (95% CI -3.7 to -0.7, p=.004). Each 1%-point rise in ESFI and MFFI corresponded to 0.17%- (95% CI 0.05-0.3, p=.01) and 0.20%-point (95% CI 0.1-0.3 p<.001) increases in relative slippage, respectively. Notably, after adjusting for confounders, each cm2 increase in PsoasfCSA and cm2/m2 in PsoasHI was associated with an increase in relative slippage by 0.3% (95% CI 0.1-0.6, p=.004) and 1.1%-points (95% CI 0.4-1.7, p=.001). While MFfCSA tended to be negatively associated with slippage, this did not reach statistical significance (p=.105). However, each 1%-point increase in MFFI and ESFI corresponded to increases of 0.15% points (95% CI 0.05-0.24, p=.002) and 0.14% points (95% CI 0.01-0.27, p=.03) in relative slippage, respectively. CONCLUSION: This study found a significant association between paraspinal muscle status and severity of slippage in DLS. Whereas higher degeneration of the ES and MF correlate with a higher degree of slippage, the opposite was found for the psoas. These findings suggest that progressive muscular imbalance between posterior and anterior paraspinal muscles could contribute to the progression of slippage in DLS.

Decision-making Algorithm for the Surgical Treatment of Degenerative Lumbar Spondylolisthesis of L4/L5.

STUDY DESIGN: A retrospective analysis of prospectively collected data. OBJECTIVE: To report the decision-making process for decompression alone (DA) and decompression and fusion (DF) at a tertiary orthopedic center and compare the operative outcomes between both groups. BACKGROUND: Controversy exists around the optimal operative treatment for DLS, either with DF or DA. Although previous studies tried to establish specific indications, clinical decision-making algorithms are needed. MATERIALS AND METHODS: Patients undergoing spinal surgery for DLS at L4/5 were retrospectively analyzed. A survey of spine surgeons was performed to identify factors influencing surgical decision-making, and their association with the surgical procedure was tested in the clinical data set. We then developed a clinical score based on the statistical analysis and survey results. The predictive capability of the score was tested in the clinical data set with a receiver operating characteristic (ROC) analysis. To evaluate the clinical outcome, two years follow-up postoperative Oswestry Disability Index (ODI), postoperative low back pain (LBP) (Numeric Analog Scale), and patient satisfaction were compared between the DF and DA groups. RESULTS: A total of 124 patients were included in the analysis; 66 received DF (53.2%) and 58 DA (46.8%). Both groups showed no significant differences in postoperative ODI, LBP, or satisfaction. The degree of spondylolisthesis, facet joint diastasis and effusion, sagittal disbalance, and severity of LBP were identified as the most important factors for deciding on DA or DF. The area under the curve of the decision-making score was 0.84. At a cutoff of three points indicating DF, the accuracy was 80.6%. CONCLUSIONS: The two-year follow-up data showed that both groups showed similar improvement in ODI after both procedures, validating the respective decision. The developed score shows excellent predictive capabilities for the decision processes of different spine surgeons at a single tertiary center and highlights relevant clinical and radiographic parameters. Further studies are needed to assess the external applicability of these findings.

Severe Intervertebral Vacuum Phenomenon is Associated With Higher Preoperative Low Back Pain, ODI, and Indication for Fusion in Patients With Degenerative Lumbar Spondylolisthesis.

STUDY DESIGN: Retrospective study of prospective collected data. OBJECTIVE: To analyze the association between intervertebral vacuum phenomenon (IVP) and clinical parameters in patients with degenerative spondylolisthesis. SUMMARY OF BACKGROUND DATA: IVP is a sign of advanced disc degeneration. The correlation between IVP severity and low back pain in patients with degenerative spondylolisthesis has not been previously analyzed. METHODS: We retrospectively analyzed patients with degenerative spondylolisthesis who underwent surgery. Vacuum phenomenon was measured on computed tomography scan and classified into mild, moderate, and severe. A lumbar vacuum severity (LVS) scale was developed based on vacuum severity. The associations between IVP at L4/5 and the LVS scale, preoperative and postoperative low back pain, as well as the Oswestry Disability Index was assessed. The association of IVP at L4/5 and the LVS scale and surgical decision-making, defined as decompression alone or decompression and fusion, was assessed through univariable logistic regression analysis. RESULTS: A total of 167 patients (52.7% female) were included in the study. The median age was 69 years (interquartile range 62-72). Overall, 100 (59.9%) patients underwent decompression and fusion and 67 (40.1%) underwent decompression alone. The univariable regression demonstrated a significantly increased odds ratio (OR) for back pain in patients with more severe IVP at L4/5 [OR=1.69 (95% CI 1.12-2.60), P =0.01]. The univariable regressions demonstrated a significantly increased OR for increased disability with more severe L4/L5 IVP [OR=1.90 (95% CI 1.04-3.76), P =0.04] and with an increased LVS scale [OR=1.17 (95% CI 1.02-1.35), P =0.02]. IVP severity of the L4/L5 were associated with higher indication for fusion surgery. CONCLUSION: Our study showed that in patients with degenerative spondylolisthesis undergoing surgery, the severity of vacuum phenomenon at L4/L5 was associated with greater preoperative back pain and worse Oswestry Disability Index. Patients with severe IVP were more likely to undergo fusion.

Association Between Osteoarthritis Burden and Intervertebral Disk Degeneration in Patients Undergoing Lumbar Spine Surgery for Degenerative Lumbar Spondylolisthesis.

STUDY DESIGN: A retrospective analysis of prospectively collected data. OBJECTIVE: To assess the association between intervertebral disk degeneration and hip and knee osteoarthritis (OA) in patients with degenerative lumbar spondylolisthesis. BACKGROUND: The co-occurrence of hip OA and degenerative spinal pathologies was first described as the "hip-spine syndrome" and has also been observed in knee OA. It remains unclear whether both pathologies share an underlying connection beyond demographic factors. MATERIALS AND METHODS: Intervertebral disk degeneration was classified by the Pfirrmann Classification and intervertebral vacuum phenomenon. Intervertebral vacuum phenomenon was classified into mild (1 point), moderate (2 points), and severe (3 points) at each level and combined into a lumbar vacuum score (0-15 points). Similarly, a lumbar Pfirrmann grade was calculated (5-25 points). Patients with previous hip or knee replacement surgery were classified as having an OA burden. We used multivariable regression to assess the association between OA and disk degeneration, adjusted for age, body mass index, and sex. RESULTS: A total of 246 patients (58.9% female) were included in the final analysis. Of these, 22.3% had OA burden. The multivariable linear regression showed an independent association between OA burden and lumbar vacuum (ß = 2.1, P <0.001) and Pfirrmann grade (ß = 2.6, P <0.001). Representing a 2.1 points higher lumbar vacuum and 2.6 points higher lumbar Pfirrmann grade after accounting for demographic differences. CONCLUSIONS: Our study showed that OA burden was independently associated with the severity of the intervertebral disk degeneration of the lumbar spine. These findings give further weight to a shared pathology of OA of large joints and degenerative processes of the lumbar spine. LEVEL OF EVIDENCE: 3.

Association of abdominal aortic calcification and lower back pain in patients with degenerative spondylolisthesis.

ABSTRACT: Abdominal aortic calcification (AAC) is hypothesized to lead to ischemic pain of the lower back. This retrospective study aims to identify the relationship between AAC and lower back pain (LBP) in patients with degenerative lumbar spondylolisthesis. Lower back pain was assessed preoperatively and 2 years after surgery using the numeric analogue scale. Abdominal aortic calcification was assessed according to the Kauppila classification and was grouped into no, moderate, and severe. A multivariable regression, adjusted for age, sex, body mass index, hypertension, and smoking status, was used to assess the association between AAC and preoperative/postoperative LBP as well as change in LBP after surgery. A total of 262 patients were included in the final analysis. The multivariable logistic regression demonstrated an increased odds ratio (OR) for preoperative LBP ≥ 4 numeric analogue scale (OR = 9.49, 95% confidence interval [CI]: 2.71-40.59, P < 0.001) and postoperative LBP ≥ 4 (OR = 1.72, 95% CI: 0.92-3.21, P = 0.008) in patients with severe AAC compared with patients with no AAC. Both moderate and severe AAC were associated with reduced improvement in LBP after surgery (moderate AAC: OR = 0.44, 95% CI: 0.22-0.85, P = 0.016; severe AAC: OR = 0.41, 95% CI: 0.2-0.82, P = 0.012). This study demonstrates an independent association between AAC and LBP and reduced improvement after surgery. Evaluation of AAC could play a role in patient education and might be considered part of the differential diagnosis for LBP, although further prospective studies are needed.

Predicting postoperative outcomes in lumbar spinal fusion: development of a machine learning model.

BACKGROUND CONTEXT: Degenerative lumbar spondylolisthesis (DLS) is a prevalent spinal disorder, often requiring surgical intervention. Accurately predicting surgical outcomes is crucial to guide clinical decision-making, but this is challenging due to the multifactorial nature of postoperative results. Traditional risk assessment tools have limitations, and with the advent of machine learning, there is potential to enhance the precision and comprehensiveness of preoperative evaluations. PURPOSE: We aimed to develop a machine-learning algorithm to predict surgical outcomes in patients with degenerative lumbar spondylolisthesis (DLS) undergoing spinal fusion surgery, only using preoperative data. STUDY DESIGN: Retrospective cross-sectional study. PATIENT SAMPLE: Patients with DLS undergoing lumbar spinal fusion surgery. OUTCOME MEASURES: This study aimed to predict the occurrence of lower back pain (LBP) ≥4 on the numeric analogue scale (NAS) 2 years after surgery. LBP was evaluated as the average pain patients experienced at rest in the week before questioning. NAS ranges from 0 to 10, 0 representing no pain and 10 representing the worst pain imaginable. METHODS: We conducted a retrospective analysis of prospectively enrolled patients who underwent spinal fusion surgery for degenerative lumbar spondylolistheses at our institution in the United States between January 2016 and December 2018. The initial patient characteristics to be included in the training of the model were chosen by clinical expertise and through a literature review and included demographic characteristics, comorbidities, and radiologic features. The data was split into a training and validation datasets using a 60/40 split. Four different machine learning models were trained, including the modern XGBoost model, logistic regression, random-forest, and support vector machine (SVM). The models were evaluated according to the area under the curve (AUC) of the receiver operating characteristics (ROC) curve. An AUC of 0.7 to 0.8 was considered fair, 0.8 to 0.9 good, and ≥ 0.9 excellent. Additionally, a calibration plot and the Brier score were calculated for each model. RESULTS: A total of 135 patients (66% female) were included. A total of 38 (28%) patients reported LBP ≥ 4 after 2 years, representing the positive class. The XGBoost model demonstrated the best performance in the validation set with an AUC of 0.81 (95% CI 0.67-0.95). The other machine learning models performed significantly worse: with an AUC of 0.52 (95% CI 0.37-0.68) for the SVM, 0.56 (95% CI 0.37-0.76) for the logistic regression and an AUC of 0.56 (95% CI 0.37-0.78) for the random forest. In the XGBoost model age, composition of the erector spinae, and severity of lumbar spinal stenosis as were identified as the most important features. CONCLUSIONS: This study represents a novel approach to predicting surgical outcomes in spinal fusion patients. The XGBoost demonstrated a better performance compared with classical models and highlighted the potential contributions of age and paraspinal musculature atrophy as significant factors. These findings have important implications for enhancing patient care through the identification of high-risk individuals and modifiable risk factors. As the incorporation of machine learning algorithms into clinical decision-making continues to gain traction in research and clinical practice, our insights reinforce this trajectory by showcasing the potential of these techniques in forecasting surgical results.

Examining the Role of Paraspinal Musculature in Post-Operative Disability after Lumbar Fusion Surgery for Degenerative Spondylolisthesis.

STUDY DESIGN: Retrospective analysis of prospectively enrolled patients. OBJECTIVE: To evaluate the relationship between paraspinal muscle (PM) atrophy and Oswestry Disability Index (ODI) improvement after spinal fusion surgery for degenerative lumbar spondylolisthesis (DLS). BACKGROUND: Atrophy of the PM is linked to multiple spinal conditions, sagittal malalignment, and increased postoperative complications. However, only limited evidence for the effect on patient-reported outcomes exists. METHODS: Patients with DLS undergoing decompression and fusion surgery were analyzed. Patients with missing follow-up, no imaging, or inadequate image quality were excluded. The Oswestry Disability Index (ODI) was assessed preoperatively and two years postoperatively. A cross-sectional area of the PM was measured on a T2-weighted Magnetic Resonance Imaging (MRI) sequence at the upper endplate of L4. Based on the literature, a 10-point improvement cut-off was defined as the minimum clinically important difference (MCID). Patients with a baseline ODI below the MCID were excluded. Logistic regression was used to calculate the association between fatty infiltration (FI) of the PM and improvement in ODI, adjusted for age, sex, and body mass index (BMI). RESULTS: 133 patients were included in the final analysis, with only two lost to follow-up. The median age was 68 years (IQR 62 - 73). The median preoperative ODI was 23 (IQR 17 - 28), and 76.7% of patients showed improvement in their ODI score by at least 10 points. In the multivariable regression, FI of the erector spinae and multifidus increased the risk of not achieving clinically relevant ODI improvement (P=0.01 and P<0.001, respectively). No significant association was found for the psoas muscle (P=0.158). CONCLUSIONS: This study demonstrates that FI of the erector spinae and multifidus, is significantly associated with less likelihood of clinically relevant ODI improvement following decompression and fusion. Further research is needed to assess the effect of interventions.

Differences in imaging and clinical characteristics are associated with higher rates of decompression-fusion versus decompression-alone in women compared to men for lumbar degenerative spondylolisthesis.

PURPOSE: The goals were to ascertain if differences in imaging/clinical characteristics between women and men were associated with differences in fusion for lumbar degenerative spondylolisthesis. METHODS: Patients had preoperative standing radiographs, CT scans, and intraoperative fluoroscopic images. Symptoms and comorbidity were obtained from patients; procedure (fusion-surgery or decompression-alone) was obtained from intraoperative records. With fusion surgery as the dependent variable, men and women were compared in multivariable logistic regression models with clinical/imaging characteristics as independent variables. The sample was dichotomized, and analyses were repeated with separate models for men and women. RESULTS: For 380 patients (mean age 67, 61% women), women had greater translation, listhesis angle, lordosis, and pelvic incidence, and less diastasis and disc height (all p ≤ 0.03). The rate of fusion was higher for women (78% vs. 65%; OR 1.9, p = 0.008). Clinical/imaging variables were associated with fusion in separate models for men and women. Among women, in the final multivariable model, less comorbidity (OR 0.5, p = 0.05), greater diastasis (OR 1.6, p = 0.03), and less anterior disc height (OR 0.8, p = 0.0007) were associated with fusion. Among men, in the final multivariable model, opioid use (OR 4.1, p = 0.02), greater translation (OR 1.4, p = 0.0003), and greater diastasis (OR 2.4, p = 0.0002) were associated with fusion. CONCLUSIONS: There were differences in imaging characteristics between men and women, and women were more likely to undergo fusion. Differences in fusion within groups indicate that decisions for fusion were based on composite assessments of clinical and imaging characteristics that varied between men and women.

Emerging Need for PROMs to Measure the Impact of Spine Disorders on Overall Health and Well-being: Measuring Expectations as an Example for Lumbar Degenerative Spondylolisthesis.

Background: Assessing the impact of spine disorders such as lumbar degenerative spondylolisthesis (LDS) on overall health is a component of quality of care that may not be comprehensively captured by spine-specific and single-attribute patient-reported outcome measures (PROMs). Purpose: We sought to compare PROMs to the Lumbar Surgery Expectations Survey ("Expectations Survey"), which addresses multiple aspects of health and well-being, and to compare the relevance of surgeon-selected versus survey-selected Patient-Reported Outcomes Measurement Information System (PROMIS) items to LDS. Methods: In a cross-sectional study, 379 patients with LDS preoperatively completed the Expectations Survey, Numerical Rating Pain Scales, Oswestry Disability Index (ODI), and PROMIS computer-adaptive physical function, pain, and mental health surveys. Expectations Survey scores were compared to PROMs with correlation coefficients (indicating strengths of relationships) and probability values (indicating associations by chance). Surgeons reviewed physical function questions to identify those particularly relevant to LDS. Results: Patients' mean age was 67 years, 64% were women, and 83% had single-level and 17% had multiple-level LDS. Probability values between the Expectations Survey and PROMs were reliable, but strengths of relationships were only mild to moderate, indicating PROMs did not comprehensively capture the impact of LDS. None of the surgeon-selected PROMIS physical function questions were posed to patients. Conclusion: This cross-sectional study found PROMs to be reliably associated but not strongly correlated with the Expectations Survey, which addresses the whole-patient impact of LDS. New measures that complement PROMIS and ODI should be developed to capture the whole-person effects of LDS and permit attribution of LDS treatments to overall health.

High preoperative expectations and postoperative fulfillment of expectations two years after decompression alone and decompression plus fusion for lumbar degenerative spondylolisthesis.

BACKGROUND CONTEXT: Fulfillment of expectations is a patient-centered outcome that has not been assessed based on fusion status for lumbar degenerative spondylolisthesis (LDS). PURPOSE: To compare preoperatively cited expectations and 2-year postoperative fulfillment of expectations between patients undergoing decompression alone (no-fusion) vs. decompression plus fusion (fusion) for LDS. STUDY DESIGN: Longitudinal cohort. PATIENT SAMPLE: A total of 357 patients. OUTCOME MEASURES: Postoperative version of Lumbar Spine Surgery Expectations Survey, Oswestry Disability Index (ODI), satisfaction with surgery. METHODS: Preoperatively patients completed the 20-item Expectations Survey measuring amount of 'improvement expected' for symptoms, physical function, and psychosocial well-being (score range 0-100); two years postoperatively patients completed the follow-up survey measuring 'improvement received'. The proportion of expectations fulfilled was calculated as 'improvement received' divided by 'improvement expected' (<1 some expectations fulfilled, >1 expectations surpassed). Patients also completed the ODI, SF-12 mental health subscale, satisfaction with surgery, and measures of comorbidity and psychosocial status, including social support (ie, help at home) and prior orthopedic surgery (ie, hip/knee arthroplasty). RESULTS: Patients' mean age was 67 years, 61% were women, 82% had single-level LDS, 73% had fusion, and mean follow-up was 26.2 months. Compared to patients with no-fusion, patients with fusion had more pain, spinal instability, use of opioids, disability, and greater preoperative Expectations Survey scores (69 vs 74, p=.008). The proportion of expectations fulfilled postoperatively was high and similar for both groups (.82 vs. .79, p=.40), but more variable for fusion (IQR .32 vs. .40). In multivariable analysis with the proportion as the dependent variable, fulfilled expectations was associated with better mental well-being (coeff=1.1, 95% CI 0.6-1.7, p=.0001) and more social support (coeff=3.3, 95% CI 1.1-5.6, p=.004) and unfulfilled expectations was associated with prior arthroplasty (coeff=-8.6, 95% CI -15.4-(-1.9), p=.01) and subsequent lumbar surgery (coeff=-15.6, 95% CI -25.2-(-6.0), p=.002). Similar associations were found for change in ODI and satisfaction. CONCLUSIONS: Patients had high preoperative expectations of surgery with greater expectations for decompression-fusion compared to decompression-alone. Although more variable for the fusion group, both groups had high proportions of expectations fulfilled. This study highlights the spectrum of clinical and psychosocial variables that impacts fulfillment of expectations for both decompression-alone and decompression-fusion for LDS surgery.

Instability Missed by Flexion-Extension Radiographs Subsequently Identified by Alternate Imaging in L4-L5 Lumbar Degenerative Spondylolisthesis.

STUDY DESIGN: Cross-sectional preoperative and intraoperative imaging study of L4-L5 lumbar degenerative spondylolisthesis (LDS). OBJECTIVE: To determine if alternate imaging modalities would identify LDS instability that did not meet the criteria for instability based on comparison of flexion and extension radiographs. SUMMARY OF BACKGROUND DATA: Pain may limit full flexion and extension maneuvers and thereby lead to underreporting of true dynamic translation and angulation in LDS. Alternate imaging pairs may identify instability missed by flexion-extension. MATERIALS AND METHODS: Consecutive patients scheduled for surgery for single-level L4-L5 LDS had preoperative standing radiographs in the lateral, flexion, and extension positions, supine computed tomography (CT) scans, and intraoperative fluoroscopic images in the supine and prone positions after anesthesia but before incision. Instability was defined as translation ≥3.5 mm or angulation ≥11° between the following pairs of images: (1) flexion-extension; (2) CT-lateral; (3) lateral-intraoperative supine; (4) lateral-intraoperative prone; and (5) intraoperative supine-prone. RESULTS: Of 240 patients (mean age 68 y, 54% women) 15 (6%) met the criteria for instability by flexion-extension, and 225 were classified as stable. Of these 225, another 84 patients (35% of total enrollment) were reclassified as unstable by comparison of CT-lateral images (21 patients) and by lateral-intraoperative images (63 patients). Nine of the 15 patients diagnosed with instability by flexion-extension had fusion (60%), and 68 of the 84 patients reclassified as unstable by other imaging pairs had fusion (81%) ( P =0.07). The 84 reclassified patients were more likely to undergo fusion compared with the 141 patients who persistently remained classified as stable (odds ratio=2.6, 95% CI: 1.4-4.9, P =0.004). CONCLUSIONS: Our study provides evidence that flexion and extension radiographs underreport the dynamic extent of LDS and therefore should not be solely relied upon to ascertain instability. These findings have implications for how instability should be established and the extent of surgery that is indicated.

Quantitative CT for Preoperative Assessment of Lumbar Degenerative Spondylolisthesis: The Unique Impact of L4 Bone Mineral Density on Single-Level Disease.

Background: Quantitative computed tomography (qCT) efficiently measures 3-dimensional vertebral bone mineral density (BMD), but its utility in measuring BMD at various vertebral levels in patients with lumbar degenerative spondylolisthesis (LDS) is unclear. Purpose: We sought to determine whether qCT could differentiate BMD at different levels of LDS, particularly at L4-L5, the most common single level for LDS. In addition, we sought to describe patterns of BMD for single-level and multiple-level LDS. Methods: We conducted a study of patients undergoing surgery for LDS who were part of a larger longitudinal study comparing preoperative and intraoperative images. Preoperative patients were grouped as single-level or multiple-level LDS, and qCT BMD was obtained for L1-S1 vertebrae. Mean BMD was compared with literature reports; in multivariable analyses, BMD of each vertebra was assessed according to the level of LDS, controlling for covariates and for BMD of other vertebrae. Results: Of 250 patients (mean age: 67 years, 64% women), 22 had LDS at L3-L4 only, 170 at L4-L5 only, 13 at L5-S1 only, and 45 at multiple levels. Compared with other disorders reported in the literature, BMD in our sample similarly decreased from L1 to L3 then increased from L4 to S1, but mean BMD per vertebra in our sample was lower. Nearly half of our sample met criteria for osteopenia. In multivariable analysis controlling for BMD at other vertebrae, lower L4 BMD was associated with LDS at L4-L5, greater pelvic incidence minus lumbar lordosis, and not having diabetes. In contrast, in similar multivariable analysis, greater L4 BMD was associated with LDS at L3-L4. Bone mineral density of L3 and L5 was not associated with LDS levels. Conclusion: In our sample of preoperative patients with LDS, we observed lower BMD for LDS than for other lumbar disorders. L4 BMD varied according to the level of LDS after controlling for covariates and BMD of other vertebrae. Given that BMD can be obtained from routine imaging, our findings suggest that qCT data may be useful in the comprehensive assessment of and strategy for LDS surgery. More research is needed to elucidate the cause-effect relationships among spinopelvic alignment, LDS, and BMD.

Psychological Stress Reported at the Start of the COVID-19 Pandemic and Subsequent Stress and Successful Coping in Patients With Rheumatic Diseases: A Longitudinal Analysis.

OBJECTIVE: In a cohort assembled during the height of mortality-associated coronavirus disease 2019 (COVID-19) in New York City, the objectives of this qualitative-quantitative mixed-methods study were to assess COVID-related stress at enrollment with subsequent stress and clinical and behavioral characteristics associated with successful coping during longitudinal follow-up. METHODS: Patients with rheumatologist-diagnosed rheumatic disease taking immunosuppressive medications were interviewed in April 2020 and were asked open-ended questions about the impact of COVID-19 on psychological well-being. Stress-related responses were grouped into categories. Patients were interviewed again in January-March 2021 and asked about interval and current disease status and how well they believed they coped. Patients also completed the 29-item Patient-Reported Outcomes Measurement Information System (PROMIS-29) measuring physical and emotional health during both interviews. RESULTS: Ninety-six patients had follow-ups; 83% were women, and mean age was 50 years. Patients who reported stress at enrollment had improved PROMIS-29 scores, particularly for the anxiety subscale. At the follow-up, patients reported persistent and new stresses as well as numerous self-identified coping strategies. Overall coping was rated as very well (30%), well (48%), and neutral-fair-poor (22%). Based on ordinal logistic regression, variables associated with worse overall coping were worse enrollment-to-follow-up PROMIS-29 anxiety (odds ratio [OR], 4.4; confidence interval [CI], 1.1-17.3; p = 0.03), not reporting excellent/very good disease status at follow-up (OR, 2.7; CI, 1.1-6.5; p = 0.03), pandemic-related persistent stress (OR, 5.7; CI, 1.6-20.1; p = 0.007), and pandemic-related adverse long-lasting effects on employment (OR, 6.1; CI, 1.9-20.0; p = 0.003) and health (OR, 3.0; CI, 1.0-9.0; p = 0.05). CONCLUSIONS: Our study reflects the evolving nature of COVID-related psychological stress and coping, with most patients reporting they coped well. For those not coping well, multidisciplinary health care providers are needed to address long-lasting pandemic-associated adverse consequences.