Development and external validation of a predictive model for prolonged length of hospital stay in elderly patients undergoing lumbar fusion surgery: comparison of three predictive models.

PURPOSE: This study aimed to develop a predictive model for prolonged length of hospital stay (pLOS) in elderly patients undergoing lumbar fusion surgery, utilizing multivariate logistic regression, single classification and regression tree (hereafter, "classification tree") and random forest machine-learning algorithms. METHODS: This study was a retrospective review of a prospective Geriatric Lumbar Disease Database. The primary outcome measure was pLOS, which was defined as the LOS greater than the 75th percentile. All patients were grouped as pLOS group and non-pLOS. Three models (including logistic regression, single-classification tree and random forest algorithms) for predicting pLOS were developed using training dataset and internal validation using testing dataset. Finally, online tool based on our model was developed to assess its validity in the clinical setting (external validation). RESULTS: The development set included 1025 patients (mean [SD] age, 72.8 [5.6] years; 632 [61.7%] female), and the external validation set included 175 patients (73.2 [5.9] years; 97[55.4%] female). Multivariate logistic analyses revealed that older age (odds ratio [OR] 1.06, p < 0.001), higher BMI (OR 1.08, p = 0.002), number of fused segments (OR 1.41, p < 0.001), longer operative time (OR 1.02, p < 0.001), and diabetes (OR 1.05, p = 0.046) were independent risk factors for pLOS in elderly patients undergoing lumbar fusion surgery. The single-classification tree revealed that operative time ≥ 232 min, delayed ambulation, and BMI ≥ 30 kg/m2 as particularly influential predictors for pLOS. A random forest model was developed using the remaining 14 variables. Intraoperative EBL, operative time, delayed ambulation, age, number of fused segments, BMI, and RBC count were the most significant variables in the final model. The predictive ability of our three models was comparable, with no significant differences in AUC (0.73 vs. 0.71 vs. 0.70, respectively). The logistic regression model had a higher net benefit for clinical intervention than the other models. The nomogram was developed, and the C-index of external validation for PLOS was 0.69 (95% CI, 0.65-0.76). CONCLUSION: This investigation produced three predictive models for pLOS in elderly patients undergoing lumbar fusion surgery. The predictive ability of our three models was comparable. Logistic regression model had a higher net benefit for clinical intervention than the other models. Our predictive model could inform physicians about elderly patients with a high risk of pLOS after surgery.

Association between delayed ambulation and increased risk of adverse events after lumbar fusion surgery in elderly patients.

PURPOSE: The relationship between delayed ambulation (DA) and postoperative adverse events (AEs) following transforaminal lumbar interbody fusion (TLIF) in elderly patients remains elusive. The aim of our study was to evaluate the effects of DA on the postoperative AEs including complications, readmission and prolonged length of hospital stay (LOS). METHODS: This was a retrospective analysis of a prospectively established database of elderly patients (aged 65 years and older) who underwent TLIF surgery. The early ambulation (EA) group was defined as patients ambulated within 48 h after surgery, whereas the delayed ambulation (DA) group was patients ambulated at a minimum of 48 h postoperatively. The DA patients were 1:1 propensity-score matched to the EA patients based on age, gender and the number of fused segments. Univariate analysis was used to compare postoperative outcomes between the two groups, and multivariate logistic regression analysis was used to identify risk factors for adverse events and DA. RESULTS: After excluding 125 patients for various reasons, 1025 patients (≤ 48 h: N = 659 and > 48 h: N = 366) were included in the final analysis. After propensity score matching, there were 326 matched patients in each group. There were no significant differences in the baseline data and the surgery-related variables between the two groups (p > 0.05). The patients in the DA group had a significant higher incidence of postoperative AEs (46.0% vs. 34.0%, p = 0.002) and longer LOS (p = 0.001). Multivariate logistic regression identified that age, operative time, diabetes, and DA were independently associated with postoperative AEs, whereas greater age, higher international normalized ratio, and intraoperative estimated blood loss were identified as independent risk factors for DA. CONCLUSIONS: Delayed ambulation was an independent risk factor for postoperative AEs after TLIF in elderly patients. Older age, increased intraoperative blood loss and worse coagulation function were associated with delayed ambulation.

Preoperative Zung depression scale predicts outcomes in older patients undergoing short-segment fusion surgery for degenerative lumbar spinal disease.

PURPOSE: To identify the relationship between depression measured by Zung depression rating scale (ZDRS) and postoperative outcomes (including the patients reported outcomes [PRO] and clinical outcomes) two years after short-segment fusion surgery for degenerative lumbar spinal disease in older patients (aged 75 years and older). METHODS: We enrolled patients who underwent short-segment fusion surgery for lumbar degenerative disease from May 2018 to June 2020. All patients were assessed for depression using the ZDRS. Patients were included in the depression group and not-depressed group based on their scores. Preoperative baseline data were collected on characteristics, comorbidities, laboratory data, pain levels (visual analogue scale [VAS]), functional status (Oswestry Disability Index [ODI]), and surgery-related variables. The primary outcomes were PRO measures, including VAS, ODI and satisfaction two years after lumbar fusion surgery. Other outcomes included postoperative complications, the length of stay, and reoperation. Univariate and multivariate analyses were performed to identify the risk factors for poor satisfaction. RESULTS: A total of 231 patients (201 in not-depressed and 30 in depressed group) were enrolled in this study. There were no significant differences between the two groups for baseline data. Depressed group had higher rates of choices for dissatisfaction (36.7% vs. 14.0%, p = 0.015), higher VAS scores of low back pain (2.8 ± 2.3 vs. 1.6 ± 1.7, p = 0.012), and worse functional status (31.5 ± 22.5 vs 21.8 ± 19.9, p = 0.015) than the not-depressed group. Depressed patients reported significantly higher rates of postoperative complications and readmissions. Multivariate regression analysis revealed that depression (p = 0.001) was independently associated with postoperative dissatisfaction. CONCLUSION: Preoperative depression was a risk factor for postoperative dissatisfaction, worse functional status, readmission, and complications in older patients undergoing lumbar fusion surgery. Preoperative screening using the Zung depression scale helps inform decision-making when considering fusion surgery for patients aged 75 and older.

The implementation of enhanced recovery after surgery pathway in patients undergoing posterior thoracolumbar fusion for degenerative spinal deformity.

PURPOSE: The prevalence of degenerative spinal deformity (DSD) and the increased cost of correction surgery impose substantial burdens on the health care and insurance system. The aim of our study was to investigate the effects of the implementation of Enhanced Recovery After Surgery (ERAS) protocol on postoperative outcomes after complex spinal surgery. METHODS: A retrospective analysis of prospectively established database of DSD was performed. The consecutive patients who underwent open correction surgery for degenerative spinal deformity between August 2016 and February 2022 were reviewed. We extracted demographic data, preoperative radiographic parameters, and surgery-related variables. The ERAS patients were 1:1 propensity-score matched to a historical cohort by the same surgical team based on age, gender, BMI, and number of levels fused. We then compared the length of hospital stay (LOS), physiological functional recovery, and the rates of complications and readmissions within 90 days after surgery between the groups. RESULTS: There were 108 patients included, 54 patients in the ERAS cohort, and 54 patients matched control patients in the historical cohort. The historical and ERAS cohorts were not significantly different regarding demographic characteristics, comorbidities, preoperative parameters, operative time, and reoperation rate (P > 0.05). Patients in the ERAS group had significantly shorter postoperative LOS (12.0 days vs. 15.1 days, P = 0.001), average days of drain and urinary catheters placement (3.5 days vs. 4.4 days and 1.9 days vs 4.8 days, respectively), and lower 90-day readmission rate (1.8% vs. 12.9%, P = 0.027). The first day of assisted-walking and bowel movement occurred on average 1.9 days (2.5 days vs. 4.4 days, P = 0.001) and 1.7 days (1.9 days vs. 3.6 days, P = 0.001) earlier respectively in the ERAS group. Moreover, the rate of postoperative urinary retention (3.7% vs. 16.7%, P = 0.026) and surgical site infection (0% vs. 7.4%, P = 0.046) were significantly lower with ERAS protocol applied. CONCLUSIONS: Our study confirmed that the ERAS protocol was safe and essential for patients undergoing thoracolumbar deformity surgery for DSD. The ERAS protocol was associated with a shorter postoperative LOS, a lower rate of 90-day readmission, less rehabilitation discharge, and less postoperative complications.

Paraspinal muscle degeneration and lower bone mineral density as predictors of proximal junctional kyphosis in elderly patients with degenerative spinal diseases: a propensity score matched case-control analysis.

STUDY DESIGN: Retrospective case-control study. OBJECTIVES: Proximal junctional kyphosis (PJK) is a postoperative complication involving the proximal segments which is commonly seen in patients with degenerative spine diseases (DSD). The purpose of the present study was to identify predictive factors for postoperative PJK in elderly patients with DSD. METHODS: We reviewed elderly patients with DSD who underwent thoracolumbar fusion involving no less than 3 levels. Patients who developed PJK were propensity score-matched with patients with DSD who received the same procedure but did not develop PJK. Demographic characteristics, sagittal vertical axis (SVA), computed tomography (CT) value (Hounsfield unit), and paraspinal muscle parameters were compared between PJK and non-PJK groups. RESULTS: Eighty-three PJK and non-PJK patients were selected by propensity score matching for age, sex, history of smoking, body mass index, number of fused segments, and upper instrumented vertebra (UIV) location. SVA showed no significant difference between the two groups. In PJK group, fatty infiltration (FI) in erector spinae and multifidus was significantly greater, while the relative cross-sectional area (rCSA) of erector spinae was significantly smaller than that in non-PJK group. CT value was significantly lower in PJK group. Lower erector spinae rCSA and CT value of the UIV, higher erector spinae FI and multifidus FI were identified as predictors of postoperative PJK. CONCLUSIONS: PJK is a common complication in older patients with DSD. Paraspinal muscle degeneration and low bone mineral density of the UIV are predictors of PJK. Protective measures targeting paraspinal muscles and the UIV may help prevent postoperative PJK.

Development and external validation of a nomogram for predicting postoperative adverse events in elderly patients undergoing lumbar fusion surgery: comparison of three predictive models.

BACKGROUND: The burden of lumbar degenerative diseases (LDD) has increased substantially with the unprecedented aging population. Identifying elderly patients with high risk of postoperative adverse events (AEs) and establishing individualized perioperative management is critical to mitigate added costs and optimize cost-effectiveness to the healthcare system. We aimed to develop a predictive tool for AEs in elderly patients with transforaminal lumbar interbody fusion (TLIF), utilizing multivariate logistic regression, single classification and regression tree (hereafter, "classification tree"), and random forest machine learning algorithms. METHODS: This study was a retrospective review of a prospective Geriatric Lumbar Disease Database (age ≥ 65). Our outcome measure was postoperative AEs, including prolonged hospital stays, postoperative complications, readmission, and reoperation within 90 days. Patients were grouped as either having at least one adverse event (AEs group) or not (No-AEs group). Three models for predicting postoperative AEs were developed using training dataset and internal validation using testing dataset. Finally, online tool was developed to assess its validity in the clinical setting (external validation). RESULTS: The development set included 1025 patients (mean [SD] age, 72.8 [5.6] years; 632 [61.7%] female), and the external validation set included 175 patients (73.2 [5.9] years; 97 [55.4%] female). The predictive ability of our three models was comparable, with no significant differences in AUC (0.73 vs. 0.72 vs. 0.70, respectively). The logistic regression model had a higher net benefit for clinical intervention than the other models. A nomogram based on logistic regression was developed, and the C-index of external validation for AEs was 0.69 (95% CI 0.65-0.76). CONCLUSION: The predictive ability of our three models was comparable. Logistic regression model had a higher net benefit for clinical intervention than the other models. Our nomogram and online tool ( https://xuanwumodel.shinyapps.io/Model_for_AEs/ ) could inform physicians about elderly patients with a high risk of AEs within the 90 days after TLIF surgery.

Comparison of Four Nutritional Screening Tools for Predicting Postoperative Adverse Events Following Degenerative Spinal Deformity Surgery.

STUDY DESIGN: A retrospective study. OBJECTIVE: To compare the mini nutritional assessment-short form (MNA-SF), geriatric nutritional risk index, prognostic nutritional index (PNI), and preoperative serum albumin level as predictors of postoperative adverse events (AEs) in degenerative spine deformity (DSD) patients. SUMMARY OF BACKGROUND DATA: Although various nutritional screening tools have been well evaluated in patients undergoing spinal fusion surgery, the most suitable tool for the DSD population remains uncertain at present. PATIENTS AND METHODS: The authors reviewed consecutive patients who underwent thoracolumbar fusion surgery for DSD between August 2016 and May 2023. Four screening tools were used to assess preoperative nutritional status. Patients were divided into two categories according to each screening tool, and the four screening tools were compared regarding their predictive power for postoperative AEs, including the rates of extended length of hospital stays (LOS), complications, and readmission within three months. Physical functional indicators such as time to first ambulation, nonhome discharge, and postoperative LOS were assessed as secondary outcome measures. A multivariable logistic regression analysis was used to identify factors associated with postoperative AEs. RESULTS: A total of 228 patients were included. The demographic characteristics, underlying disease, and magnitude of correction were not significantly different between well-nourished and malnourished groups. The nutritional risks shown by MNA-SF and albumin level were significantly associated with infectious complications ( P <0.05). The nutritional risk shown by MNA-SF was significantly associated with nonhome discharge, prolonged postoperative LOS (12.5±8.2 vs. 10.3±6.1, P =0.039), and delayed ambulation (3.7±2.1 vs. 2.2±1.8, P =0.001). Multivariable logistic regression revealed that PNI <50 was significantly associated with total AEs and minor AEs after DSD surgery. CONCLUSIONS: PNI was significantly associated with the incidence of total AEs and minor AEs, while preoperative albumin level and MNA-SF were more effective in predicting postoperative infectious complications and delayed recovery of physical function, respectively. LEVEL OF EVIDENCE: Level III.

The impact of frailty on clinical outcomes of older patients undergoing enhanced recovery after lumbar fusion surgery: A prospective cohort study.

BACKGROUND: Frailty is recognized as a surrogate for physiological age and has been established as a valid and independent predictor of postoperative morbidity, mortality, and complications. ERAS can enhance surgical safety by minimizing stress responses in frail patients, enabling surgeons to discharge patients earlier. However, the question of whether and to what extent the frailty impacts the post-ERAS outcomes in older patients remains. MATERIALS AND METHODS: An evidence-based ERAS program was implemented in our center from January 2019. This is a prospective cohort study of patients aged ≥75 years who underwent open transforaminal lumbar interbody fusion (TLIF) for degenerative spine disease from April 2019 to October 2021. Frailty was assessed with the Fried frailty scale (FP scale), and patients were categorized as non/prefrail (FP 0-2) or frail (FP ≥ 3). The preoperative variables, operative data, postoperative outcomes and follow-up information were compared between the two groups. Univariate and multivariate logistic regression analyses were used to identify risk factors for 90-day major complications and prolonged length of hospital stay (LOS) after surgery. RESULTS: A total of 245 patients (age of 79.8 ± 3.4 yr) who had a preoperative FP score recorded and underwent scheduled TLIF surgery were included in the final analysis. Comparisons between non-frail and prefrail/frail patients revealed no significant difference in age, sex, and surgery-related variables. Even after adjusting for multiple comparisons, the association between Fried frailty and ADL-dependency, IADL-dependency, and malnutrition remained significant. Preoperative frailty was associated with increased rates of postoperative adverse events. A higher CCI grade was an independent predictor for 90-day major complications, while Fried frailty and MNA-SF scores <12 were predictive of poor postoperative recovery. CONCLUSION: Frail older patients had more adverse post-ERAS outcomes after TLIF compared to non/prefrail older patients. Continued research and multidisciplinary collaboration will be essential to refine and optimize protocols for surgical care in frail older adults.

Safety and benefit of ambulation within 24 hours in elderly patients undergoing lumbar fusion: propensity score matching study of 882 patients.

BACKGROUND CONTEXT: Elderly patients are less likely to recover from lumbar spine fusion (LSF) as rapidly compared with younger patients. However, there is still a lack of research on the effect of early ambulation on elderly patients undergoing LSF surgery for lumbar degenerative disorders. PURPOSE: To evaluate the safety and benefit of ambulation within 24 hours in elderly patients who underwent LSF. STUDY DESIGN: A retrospective study. PATIENT SAMPLE: Consecutive patients (aged 65 and older) who underwent elective transforaminal lumbar interbody fusion surgery for degenerative disorders from January 2019 to October 2022. OUTCOME MEASURES: Outcome measures included postoperative complications, postoperative drainage (mL), laboratory test data, length of hospital stay [LOS], readmission and reoperation within 3 months. METHODS: Early ambulation patients (ambulation within 24 hours after surgery) were propensity-score matched 1:1 to a delayed ambulation patients (ambulation at a minimum of 48 hours postoperatively) based on age, intraoperative blood loss, and number of fused segments. The incidence of postoperative adverse events (AEs, including rates of complications, readmission, and prolonged LOS) and the average LOS were used to assess the safety and benefit of early ambulation, respectively. Multivariable regression analysis was performed to assess the association between early ambulation and postoperative AEs. The risk factors for delayed ambulation were also determined using multivariable logistic analyses. RESULTS: A total of 998 patients with LSF surgery were reviewed in this study. After excluding 116 patients for various reasons, 882 patients (<24 hours: N=350, 24-48 hours: N=230, and >48 hours: N= 302) were included in the final analysis. After matching, sex, BMI, preoperative comorbidities, laboratory test data and surgery-related variables were comparable between the groups. The incidence of postoperative AEs was significantly lower in the EA group (44.3% vs. 64.0%, p<.001). The average postoperative LOS of the EA group was 2 days shorter than the DA group (6.5 days vs. 8.5 days, p<.001). Patients in the EA group had a significantly lower rate of prolonged LOS compared with the DA group (35.1% vs. 55.3%, p<.001). There was no significant difference in postoperative drainage volumes between the two groups. Multivariable analysis identified older age (odds ratio [OR] 1.07, p<.001), increased intraoperative EBL (OR 1.002, p=.001), and higher international normalization ratio (OR 10.57, p=.032) as significant independent risk factors for delayed ambulation. CONCLUSIONS: Ambulation within 24 hours after LSF surgery is independently associated fewer AEs and shorter hospital stays in elderly patients. Implementing the goal of ambulation within 24 hours after LSF surgery into enhanced recovery after surgery protocols for elderly patients seems appropriate. Older age, increased intraoperative blood loss and worse coagulation function are associated with delayed ambulation.

Incidence and risk factors for early and late reoperation following lumbar fusion surgery.

STUDY DESIGN: Retrospective cohort study. PURPOSE: The aim of our study was to determine the rates and indications of reoperations following primary lumbar fusion, as well as the independent risk factors for early and late reoperation. METHODS: We retrospectively reviewed patients who underwent lumbar fusion surgery between January 2017 and March 2020. All patients were followed up for more than 2 years. Characteristics, laboratory tests, primary diagnosis and surgery-related variables were compared among the early reoperation (< 3 months), the late reoperation (> 3 months) and the non-reoperation groups. Multivariable logistic regression analysis was used to identify independent risk factors for early and late reoperations. RESULTS: Of 821 patients included in our studies, 34 patients underwent early reoperation, and 36 patients underwent late reoperation. The cumulative reoperation rate was about 4.1% (95% CI 3.8-4.5%) at 3 months, 6.2% (95% CI 5.9-6.5%) at 1 year and 8.2% (95% CI 8.0-8.5%) at 3 years. Multivariable analysis indicated that osteoporosis (odds ratio [OR] 3.6, 95% CI 1.2-10.5, p = 0.02) and diabetes (OR 2.1, 95% CI 1.1-4.5, p = 0.04) were independently associated with early reoperation and multilevel fusion (OR 2.4, 95% CI 1.1-5.4, p = 0.03) was independently associated with late reoperation. CONCLUSIONS: The most common reasons for early reoperation and late operation were surgical site infection and adjacent segment diseases, respectively. Osteoporosis and diabetes were independent risk factors for early reoperation, and multilevel fusion was independent risk factor for late reoperation. Surgeons should pay more attention to these patients, and future studies should consider the effects of follow-up periods on results.

Patients Older Than 75 Years Undergoing Polysegmental Lumbar Fusion Surgery Can also Benefit from Enhanced Recovery After Surgery Program.

Purpose: To compare pain scores (visual analog scale) on postoperative days 1-3 and length of stay after implementing enhanced recovery after surgery (ERAS) in elderly patients undergoing multi-segments lumbar fusion surgery. Methods: We performed a retrospective analysis of prospectively collected data, patients older than 75 years were enrolled in the study. We selected two periods, before (Pre-ERAS, n =54 patients) and after (ERAS, n =46 patients) implementation of ERAS. Data were collected on patient demographics, operative and perioperative details, 30-day readmission. The primary outcome was the length of stay (LOS), and the secondary outcomes were postoperative mean pain scores on postoperative days (POD) 1-3 and 30-day readmission rates. Results: A total of 100 patients (46 in ERAS and 54 in pre-ERAS) were enrolled in this study. There were no significant differences in age, sex, body mass index (BMI), smoking and comorbidities between the groups. However, there was a significant difference in pain on postoperative day (POD) 1 (5.31 ± 1.98 vs 4.37 ± 0.85, p = 0.002), while there was no difference in postoperative complications. The mean LOS was significantly shorter in the ERAS than in the pre-ERAS group, it reduced from 12.29 ± 3.93 to 9.45 ± 2.72 days (p < 0.001). Conclusion: To our knowledge, this is the first ERAS protocol used in patients (older than 75 years) undergoing polysegmental lumbar fusion surgery. Pain scores on POD 1 and LOS were significantly lower without increased adverse events after implementation of ERAS. This finding suggests that elderly people (>75 years of age) undergoing polysegmental lumbar fusion surgery could also benefit from ERAS.

The Charlson Comorbidity Index and depression are associated with satisfaction after short-segment lumbar fusion in patients 75 years and older.

Background: The rate and volume of lumbar spinal fusion (LSF) surgery performed for patients aged 75 years and older increased in recent years. The purposes of our study were to identify factors associated with postoperative dissatisfaction and evaluate the predictive value of comprehensive geriatric assessment (CGA) for dissatisfaction at 2 years after elective short-segment (one- or two- level) LSF in patients aged 75 and older. Methods: This was a retrospective study using a prospectively collected database of consecutive patients (aged 75 and older) who underwent elective short-segment transforaminal lumbar interbody fusion surgery for degenerative diseases from June 2018 to May 2020. Preoperative CGA consisting six domains was performed for each patient 1 day before the operative day. Univariate and multivariate analyses were performed to identify factors that predict for dissatisfaction with surgical treatment. The primary outcome was patient satisfaction with LSF surgery, as measured by the North American Spine Society (NASS) satisfaction scale. Secondary outcomes included postoperative complications, the length of stay, visual analog scale (VAS), and Oswestry Disability Index. Results: A total of 211 patients were available for a follow-up at 2 years and included in our final study cohort with a mean age of 80.0 years. A total of 175 patients (82.9%) were included in the satisfied group, and 36 patients (17.1%) were included in the not dissatisfied group. In the dissatisfied group, there was a higher incidence of postoperative complications (30.6% vs. 14.3%, p = 0.024) and greater VAS scores for lower back (4.3 ± 1.9 vs. 1.3 ± 1.4, p = 0.001) and leg (3.9 ± 2.1 vs. 0.9 ± 1.3, p = 0.001). Multivariate regression analysis revealed that patients with greater CCI score [odd ratio (OR) 2.56, 95% CI, 1.12-5.76; p = 0.030 for CCI 1 or 2 and OR 6.20, 95% CI, 1.20-28.69; p = 0.024], and depression (OR 3.34, 95% CI, 1.26-9.20; p = 0.016) were more likely to be dissatisfied compared with patients with the CCI score of 0 and without depression. Conclusions: Satisfaction after LSF in older patients (aged 75 and older) was similar to that of previously reported younger patients. Preoperative depression and higher CCI scores were independent risk factors for postoperative dissatisfaction two years after LSF surgery. These results help inform decision-making when considering LSF surgery for patients aged 75 and older.