Long-Term Outcomes of Cementless Bipolar Hemiarthroplasty in Young Patients With Osteonecrosis of the Femoral Head: The Impact of Implant Improvements and Preoperative Stage.

Introduction Advancements in bipolar hemiarthroplasty (BHA) implants in the mid-1990s contributed to favorable short-term outcomes for osteonecrosis of the femoral head (ONFH), particularly in cases without acetabular cartilage lesions. Nevertheless, long-term results remain unclear. In this study, we investigated (i) the impact of new-generation BHA implants and (ii) the effect of the preoperative stage on long-term outcomes in young patients with ONFH. Methods The records of consecutive patients with ONFH who underwent cementless BHA were retrospectively reviewed. Patients aged ≥60 years, with <10 years of follow-up, or who underwent acetabular reaming during surgery were excluded. Radiographical and clinical outcomes of patients who received first-generation BHAs and new-generation BHAs (developed after 1998) were compared by stratifying based on preoperative stage 2/3A and 3B/4, according to the Japanese Investigation Committee classification. Results Overall, 50 hips from 39 patients (mean age: 44.6 years; 64% male) with an average follow-up of 18.6 years were included. The frequency of advanced-stage patients was significantly higher in the first-generation BHA group than in the new-generation group. Regarding postoperative outcomes, the first-generation BHA group had higher acetabular erosion grades (p<0.001) and more femoral component loosening than those in the new-generation group (p<0.001). Revisions were performed in eight hips (seven in the first-generation and one in the new-generation BHA groups, p<0.001). In the new-generation BHA group, there were no significant differences in patient background between stage 2/3A and 3B/4 groups, and only one case in the stage 3B/4 group required revision. In the new-generation group, the grade of acetabular erosion was significantly higher for stage 3B/4 than stage 2/3A (p<0.001); other radiographical and clinical outcomes did not differ significantly between stages. Conclusion New-generation BHAs have significantly better implant survival rates for early-stage ONFH than those of first-generation BHAs. These findings indicate that BHA is an acceptable treatment option for early-stage ONFH in young patients.

Residual deformity after femoral neck fracture affects the location of osteonecrosis of the femoral head.

Aims: The localization of necrotic areas has been reported to impact the prognosis and treatment strategy for osteonecrosis of the femoral head (ONFH). Anteroposterior localization of the necrotic area after a femoral neck fracture (FNF) has not been properly investigated. We hypothesize that the change of the weight loading direction on the femoral head due to residual posterior tilt caused by malunited FNF may affect the location of ONFH. We investigate the relationship between the posterior tilt angle (PTA) and anteroposterior localization of osteonecrosis using lateral hip radiographs. Methods: Patients aged younger than 55 years diagnosed with ONFH after FNF were retrospectively reviewed. Overall, 65 hips (38 males and 27 females; mean age 32.6 years (SD 12.2)) met the inclusion criteria. Patients with stage 1 or 4 ONFH, as per the Association Research Circulation Osseous classification, were excluded. The ratios of anterior and posterior viable areas and necrotic areas of the femoral head to the articular surface were calculated by setting the femoral head centre as the reference point. The PTA was measured using Palm's method. The association between the PTA and viable or necrotic areas of the femoral head was assessed using Spearman's rank correlation analysis (median PTA 6.0° (interquartile range 3 to 11.5)). Results: We identified a negative correlation between PTA and anterior viable areas (rho -0.477; p = 0.001), and no correlation between PTA and necrotic (rho 0.229; p = 0.067) or posterior viable areas (rho 0.204; p = 0.132). Conclusion: Our results suggest that residual posterior tilt after FNF could affect the anteroposterior localization of necrosis.

Relationship between sacral-abdominal wall distance, movement performance, and spinal alignment in osteoporosis: a retrospective study.

BACKGROUND: Aging is associated with muscle atrophy, as typified by sarcopenia. Loss of abdominal muscle strength can cause abdominal wall laxity. The purpose of this study was to investigate the relationship between the sacral vertebra-abdominal wall distance (SAD) and movement performance using a simple lateral spine X-ray image for measuring the SAD. METHODS: In this retrospective study, we included women aged ≥ 65 years who were attending the outpatient clinic for osteoporosis at our hospital. A total of 287 patients (mean age ± SD, 76.8 ± 7.1 years) with measured SAD were included in the analysis. Patients were divided into two groups based on SAD cutoff (160 mm) and age (75 years), respectively. The patients were examined using the two-foot 20 cm rise test, 3 m Timed Up and Go (TUG) test, two-step test, open-eyed one-leg standing time, and spinal alignment. Normally distributed data are expressed as means (standard deviations) and non-normally distributed data as medians (interquartile range), depending on the results of the Kolmogorov-Smirnov test. Student's t-test and χ2 test were used for between-group comparisons. Regression analysis was performed with SAD as the objective variable. A two-sided p < 0.05 was considered statistically significant. RESULTS: The shorter SAD group performed better in the two-step test, TUG test, and open-eyed one-leg standing time (p < 0.001) as well as in the two-foot 20 cm rise test (p < 0.01) compared to the longer SAD group. Spinal alignment was better in the shorter SAD group than in the longer SAD group, with a shorter sagittal vertical axis (p < 0.001), smaller pelvic tilt (p < 0.001), and greater sacral slope (p < 0.05). CONCLUSION: SAD was associated with posterior pelvic tilt and movement performance parameters. In addition to testing for osteoporosis, movement performance parameters should be evaluated in women with osteoporosis who are aged ≥ 65 and have greater SAD (≥ 160 mm in this study). The SAD is a new assessment method, and further research is required to verify its validity and reproducibility. This is the first attempt to determine how age and SAD affect movement performance in older adults.

Long-term outcomes of Kudo type-5 unlinked surface-replacing total elbow arthroplasty for rheumatoid arthritis: a 15-year average follow-up study.

BACKGROUND: Total elbow arthroplasty (TEA) has been used for various conditions including rheumatoid arthritis (RA). While the Kudo TEA has been associated with favorable short-term outcomes, there is limited information on the longer term outcomes of this device. The aim of this study was to investigate the average 15-year outcome of Kudo type-5 TEA in patients with RA. METHODS: For this retrospective cohort study, we reviewed 29 elbows in 28 patients (Larsen grade III, n = 8; IV, n = 19; V, n = 2) with RA who underwent Kudo type-5 TEA between 1999 and 2010. The patients were followed up for a mean of 15 (range: 10-21) years. We investigated the survival with setting revision/removal as the endpoints. The risk factors for revision/loosening were assessed. RESULTS: There was a significant improvement in elbow flexion after Kudo TEA. Preoperative and postoperative Mayo Elbow Performance Score improved significantly from 60.3 to 94.7. Complications included intraoperative medial humeral epicondyle fracture (n = 2), postoperative dislocations (n = 4), deep infections (n = 1), and persistent ulnar nerve neuropathy (n = 1). Aseptic loosening was observed in 7 elbows (24.1%; humerus, n = 3; ulna, n = 3; both sides, n = 1). The causes of the 5 revisions were postoperative dislocation (n = 1), deep infection (n = 1), aseptic loosening of the humerus (n = 2), and aseptic loosening of the ulna (n = 1). All 5 elbows underwent revision of the ulnar component (n = 2) or the linked TEA (n = 3). The survival rate was 81% at 15 years after surgery with setting revision/removal as the endpoints. A deviation of ulnar component insertion angle of over 5° in any plane was associated with more revision compared to those with accurately placed implants. CONCLUSION: The Kudo type-5 elbow showed good results for up to 15 years of follow-up. However, excessive deviation of insertion angle of the ulnar component (over 5°) was associated with more revision. Due to the small sample size, robust statistical analysis of risk factors for postoperative complications or revision could not be performed, and further research is warranted to resolve this limitation.

Adjunctive intraosseous wiring fixation technique for the comminuted distal humeral fractures.

Distal humeral fractures are among the most challenging injuries to treat. Although precise repair of the articular surface is essential during surgery, accurate reconstruction of the metaphysis contributes to the overall stability of the fracture construct. The intraosseous wiring technique has been used for small-fragment fractures. However, its efficacy as an adjunct for distal humerus fixation has yet to be thoroughly investigated. This study aimed to demonstrate the applicability of this technique to comminuted, distal humeral fractures. In this retrospective case series, we describe 6 cases of intra-articular distal humerus fractures treated with this technique, followed by dual plating. We observed successful bone union in all patients, with the Mayo Elbow Performance Scores indicating "good" to "excellent" clinical outcomes for this procedure at the final follow-up. We believe that this intraosseous wiring technique should be an integral part of the toolbox of every surgeon because it is a relatively simple and highly effective procedure that requires no special instrument and can be used on various types of fractures.

Utility of Ultrasound-Guided Erector Spinae Plane Blocks for Postoperative Pain Management Following Thoracolumbar Spinal Fusion Surgery.

Purpose: The primary objective of this study is to determine if ultrasound-guided erector spinae plane blocks (ESPB) prior to thoracolumbar spinal fusion reduces opioid consumption in the first 24 hours postoperatively. Secondary objectives include ESPB effects on administration of opioids, utilization of intravenous patient-controlled analgesia (IV-PCA), pain scores, length of stay, and opioid related side effects. Methods: A retrospective cohort analysis was performed on consecutive, adult patients undergoing primary thoracolumbar fusion procedures. Demographic and baseline characteristics including diagnoses of chronic pain, anxiety, depression, and preoperative use of opioids were collected. Surgical data included surgical levels, opioid administration, and duration. Postoperative data included pain scores, opioid consumption, IV-PCA duration, opioid-related side effects, ESPB-related complications, and length of stay (LOS). Statistical analysis was performed using chi-squared and t-test analyses, multivariable analysis, and covariate adjustment with propensity score. Results: A total of 118 consecutive primary thoracolumbar fusions were identified between October 2019 and December 2021 (70 ESPB, 48 no-block [NB]). There were no significant demographic or surgical differences between groups. Median surgical time (262.50 mins vs 332.50 mins, p = 0.04), median intraoperative opioid consumption (8.11 OME vs 1.73 OME, p = 0.01), and median LOS (152.00 hrs vs 128.50 hrs, p = 0.01) were significantly reduced in the ESPB group. Using multivariable covariate adjustment with propensity score analysis only intraoperative opioid administration was found to be significantly less in the ESPB cohort. Conclusion: ESPB for thoracolumbar fusion can be performed safely in index cases. There was a reduction of intraoperative opioid administration in the ESPB group, however the care team was not blinded to the intervention. Extensive thoracolumbar spinal fusion surgery may require a different approach to regional anesthesia to be similarly effective as ESPB in isolated lumbar surgeries.

Effectiveness of Pulsed Radiofrequency Based on the Minimum Clinically Important Differences in Lumbar Spine-Related Pain in Patients without Recent Lumbar Surgery.

BACKGROUND: Pulsed radiofrequency (PRF) has been used for treatment of chronic pain in several body regions, including axial and radicular pain. However, a limited number of reports have specifically demonstrated the effectiveness of PRF for spine-related pain among nonsurgical patients. Therefore, we evaluated the effectiveness of PRF for lumbar spine-associated pain in patients without recent spine surgery, and identified the factors associated with clinically meaningful improvement in pain and quality of life. METHODS: Records of patients who underwent PRF for lumbar spine-related pain and were followed up over 6 months between 2019 and 2022 were retrospectively reviewed. Data on patient demographics, interventional factors, and patient-reported outcomes, such as the numerical rating scale (NRS) and EuroQol Group 5 Dimension 5-Level Quality of Life (EQ-5D-5 L), were collected. Patients were divided into 2 groups (responsive and nonresponsive) based on the NRS and EQ-5D-5 L scores using the previously reported minimal clinically important difference values of the NRS and EQ-5D-5 L as cutoffs, and baseline parameters were compared to identify contributing factors. RESULTS: Forty-three patients were included in the final analysis. The NRS and EQ-5D-5 L scores improved significantly at 3 and 6 months after PRF compared to baseline. The groups with NRS and EQ-5D-5 L improvement over the minimal clinically important difference had significantly higher baseline NRS and EQ-5D-5 L scores. CONCLUSIONS: Our results demonstrated that PRF improved pain and patient-reported outcomes for spine-related pain for at least 6 months in our patient cohort. PRF may be a good option for treating lumbar spine-related issues, even with severe pain and/or dysfunction.

Association of Spinal Alignment and Abdominal Circumference with Sarcopenia Status and Fall Risk in Patients with Osteoporosis: A Retrospective Study.

Since vertebral kyphosis and abdominal circumference are thought to influence sarcopenia and fall risk in osteoporosis, we evaluated sarcopenia and fall risk in patients with different measurements of abdominal circumference and sagittal longitudinal axis (SVA). In this post hoc study, 227 patients aged 65 years or more who visited an outpatient osteoporosis clinic were included in the analysis. Sarcopenia was determined from lean body mass, grip strength, and walking speed by dual energy X-ray absorptiometry; SVA (median 40 mm) and abdominal circumference (median 80 cm) were compared between the four groups, each divided into two groups. Nutritional management, falls, and fall anxiety scores were also examined. The incidence of sarcopenia was significantly increased in those with abdominal circumference < 80 cm in both the SVA < 40 mm and SVA ≥ 40 mm groups (p < 0.05). Nonetheless, the fall scores of those with SVA < 40 mm were lower than those of individuals with SVA ≥ 40 mm (p < 0.01). Based on the results of this study, SVA and abdominal circumference values may predict the risk of sarcopenia and falls. More research is needed before our results can be translated into clinical practice.

Risk Factors for Unexpected Conversion From Ambulatory to Inpatient Admission Among One-level or Two-level ACDF Patients.

STUDY DESIGN/SETTING: A retrospective observational study. OBJECTIVE: The aim of this study was to investigate the factors associated with the conversion of patient status from ambulatory anterior cervical discectomy and fusion (ACDF) to inpatient. SUMMARY OF BACKGROUND DATA: Surgeries are increasingly performed in an ambulatory setting in an era of rising healthcare costs and pressure to improve patient satisfaction. ACDF is a common ambulatory cervical spine surgery, however, there are certain patients who are unexpectedly converted from an outpatient procedure to inpatient admission and little is known about the risk factors for conversion. MATERIALS AND METHODS: Patients who underwent one-level or two-level ACDF in an ambulatory setting at a single specialized orthopedic hospital between February 2016 to December 2021 were included. Baseline demographics, surgical information, complications, and conversion reasons were compared between patients with ambulatory surgery or observational stay (stay <48 h) and inpatient (stay >48 h). RESULTS: In total, 662 patients underwent one-level or two-level ACDF (median age, 52 yr; 59.5% were male), 494 (74.6%) patients were discharged within 48 hours and 168 (25.4%) patients converted to inpatient. Multivariable logistic regression analysis demonstrated that females, low body mass index <25, American Society of Anesthesiologists classification (ASA) ≥3, long operation, high estimated blood loss, upper-level surgery, two-level fusion, late operation start time, and high postoperative pain score were considered independent risk factors for conversion to inpatient. Pain management was the most common reason for the conversion (80.0%). Ten patients (1.5%) needed reintubation or remained intubated for airway management. CONCLUSIONS: Several independent risk factors for prolonged hospital stay after ambulatory ACDF surgery were identified. Although some factors are unmodifiable, other factors, such as procedure duration, operation start time, and blood loss could be potential targets for intervention. Surgeons should be aware of the potential for life-threatening airway complications in ambulatory-scheduled ACDF.

Corrective Osteotomy of Malunited Forearm Fractures for Volar Distal Radioulnar Joint Instability: A Case Report.

CASE: A 6-year-old girl who had midshaft forearm fractures treated conservatively had volar distal radioulnar joint (DRUJ) instability caused by radial malunion at the 1-year follow-up. Corrective osteotomy was planned using computer-aided design (CAD) software based on computed tomography images. According to the analysis, the radial bone had an 8° apex volar deformation in the sagittal plane. Corrective osteotomy was performed based on preoperative planning. After surgery, the patient regained full function of her right forearm without volar DRUJ instability. CONCLUSION: This case report shows that corrective osteotomy with 3D CAD analysis can help surgeons plan and accurately correct malunion.

The anatomical positioning change of retroperitoneal organs in prone and lateral position: an assessment for single-prone position lateral lumbar surgery.

PURPOSE: There are reports that performing lateral lumbar interbody fusion (LLIF) in a prone, single position (single-prone LLIF) can be done safely in the prone position because the retroperitoneal organs reflect anteriorly with gravity. However, only a few study has investigated the safety of single-prone LLIF and retroperitoneal organ positioning in the prone position. We aimed to investigate the positioning of retroperitoneal organs in the prone position and evaluate the safety of single-prone LLIF surgery. METHODS: A total of 94 patients were retrospectively reviewed. The anatomical positioning of the retroperitoneal organs was evaluated by CT in the preoperative supine and intraoperative prone position. The distances from the centre line of the intervertebral body to the organs including aorta, inferior vena cava, ascending and descending colons, and bilateral kidneys were measured for the lumbar spine. An "at risk" zone was defined as distance less than 10 mm anterior from the centre line of the intervertebral body. RESULTS: Compared to supine preoperative CTs, bilateral kidneys at the L2/3 level as well as the bilateral colons at the L3/4 level had statistically significant ventral shift with prone positioning. The proportion of retroperitoneal organs within the at-risk zone ranged from 29.6 to 88.6% in the prone position. CONCLUSIONS: The retroperitoneal organs shifted ventrally with prone positioning. However, the amount of shift was not large enough to avoid risk for organ injuries and substantial proportion of patients had organs within the cage insertion corridor. Careful preoperative planning is warranted when considering single-prone LLIF.

The Utilization of Intraoperative Neurophysiological Monitoring for Lumbar Decompression and Fusion Surgery in New York State.

STUDY DESIGN: Retrospective database analysis. OBJECTIVE: To elucidate trends in the utilization of intraoperative neurophysiological monitoring (IONM) during elective lumbar surgery procedures and to investigate the association between the use of IONM and surgical outcomes. BACKGROUND: The routine use of IONM in elective lumbar spine procedures has recently been called into question due to longer operative time, higher cost, and other substitute advanced technologies. METHODS: The Statewide Planning and Research Cooperative System database was accessed to perform this retrospective study. The trends of IONM use for lumbar decompression and fusion procedures were investigated from 2007 to 2018. The association between IONM use and surgical outcomes was investigated from 2017 to 2018. Multivariable logistic regression analyses, as well as propensity score matching (PS-matching), were conducted to assess IONM association in neurological deficits reduction. RESULTS: The utilization of IONM showed an increase in a linear fashion from 79 cases in 2007 to 6201 cases in 2018. A total of 34,592 (12,419 monitored and 22,173 unmonitored) patients were extracted, and 210 patients (0.6%) were reported for postoperative neurological deficits. Unadjusted comparisons demonstrated that the IONM group was associated with significantly fewer neurological complications. However, the multivariable analysis indicated that IONM was not a significant predictor of neurological injuries. After the PS-matching of 23,642 patients, the incidence of neurological deficits was not significantly different between IONM and non-IONM patients. CONCLUSION: The utilization of IONM for elective lumbar surgeries continues to gain popularity. Our results indicated that IONM use was not associated with a reduction in neurological deficits and will not support the routine use of IONM for all elective lumbar surgery.

MRI-based vertebral bone quality score compared to quantitative computed tomography bone mineral density in patients undergoing cervical spinal surgery.

PURPOSE: The vertebral bone quality (VBQ) score based on magnetic resonance imaging (MRI) was introduced as a bone quality marker in the lumbar spine. Prior studies showed that it could be utilized as a predictor of osteoporotic fracture or complications after instrumented spine surgery. The objective of this study was to evaluate the correlation between VBQ scores and bone mineral density (BMD) measured by quantitative computer tomography (QCT) in the cervical spine. METHODS: Preoperative cervical CT and sagittal T1-weighted MRIs from patients undergoing ACDF were retrospectively reviewed and included. The VBQ score in each cervical level was calculated by dividing the signal intensity of the vertebral body by the signal intensity of the cerebrospinal fluid on midsagittal T1-weighted MRI images and correlated with QCT measurements of the C2-T1 vertebral bodies. A total of 102 patients (37.3% female) were included. RESULTS: VBQ values of C2-T1 vertebrae strongly correlated with each other. C2 showed the highest VBQ value [Median (range) 2.33 (1.33, 4.23)] and T1 showed the lowest VBQ value [Median (range) 1.64 (0.81, 3.88)]. There was significant weak to moderate negative correlations between and VBQ Scores for all levels [C2: p < 0.001; C3: p < 0.001; C4: p < 0.001; C5: p < 0.004; C6: p < 0.001; C7: p < 0.025; T1: p < 0.001]. CONCLUSION: Our results indicate that cervical VBQ scores may be insufficient in the estimation of BMDs, which might limit their clinical application. Additional studies are recommended to determine the utility of VBQ and QCT BMD to evaluate their potential use as bone status markers.

Distal junctional failure after corrective surgery without pelvic fixation for thoracolumbar junctional kyphosis due to osteoporotic vertebral fracture.

BACKGROUND: Thoracolumbar junctional kyphosis (TLJK) due to osteoporotic vertebral fracture (OVF) negatively impacts patients' quality of life. The necessity of pelvic fixation in corrective surgery for TLJK due to OVF remains controversial. This study aimed to: 1) evaluate the surgical outcomes of major corrective surgery for thoracolumbar junctional kyphosis due to osteoporotic vertebral fracture, and 2) identify the risk factors for distal junctional failure to identify potential candidates for pelvic fixation. METHODS: Patients who underwent surgical correction (fixed TLJK>40°, OVF located at T11-L2, the lowermost instrumented vertebra at or above L5) were included. Sagittal vertical axis, pelvic tilt, pelvic incidence, thoracic kyphosis, lumbar lordosis (L1-S1), local kyphosis, and lower lumbar lordosis (L4-S1) were assessed. Proximal and distal junctional kyphosis (P/DJK) and failures (P/DJF) were evaluated. Pre/postoperative spinopelvic parameters were compared between DJF and non-DJF patients. RESULTS: Thirty-one patients (mean age: 72.3 ± 7.9 years) were included. PJK was observed in five patients (16.1%), while DJK in 11 (35.5%). Twelve cases (38.7%) were categorized as failure. Among the patients with PJK, there was only one patient (20%) categorized as PJF and required an additional surgery. Contrary, all of eleven patients with DJK were categorized as DJF, among whom six (54.5%) required additional surgery for pelvic fixation. In comparisons between DJF and non-DJF patients, there was no significant difference in pre/postoperative LK (pre/post, p = 0.725, p = 0.950). However, statistically significant differences were observed in the following preoperative alignment parameters: SVA (p = 0.014), LL (p = 0.001), LLL (p = 0.006), PT (p = 0.003), and PI-LL (p < 0.001). CONCLUSIONS: Spinopelvic parameters, which represent the compensatory function of lumbar hyperlordosis and pelvic retroversion, have notable impacts on surgical outcomes in correction surgery for TLJK due to OVF. Surgeons should consider each patient's compensatory function when choosing a surgical approach.

Risk Factors for Ambulatory Surgery Conversion to Extended Stay Among Patients Undergoing One-level or Two-level Posterior Lumbar Decompression.

STUDY DESIGN: A retrospective observational study. OBJECTIVE: The objective of this study was to investigate the factors associated with the conversion of patient status from ambulatory surgery (AMS) to observation service (OS) (<48 h) or inpatient (>48 h). SUMMARY OF BACKGROUND DATA: AMS is becoming increasingly common in the United States because it is associated with a similar quality of care compared with inpatient surgery, significant costs reduction, and patients' desire to recuperate at home. However, there are instances when AMS patients may be subjected to extended hospital stays. Unanticipated extension of hospitalization stays can be a great burden not only to patients but to medical providers and insurance companies alike. MATERIALS AND METHODS: Data from 1096 patients who underwent one-level or two-level lumbar decompression AMS at an in-hospital, outpatient surgical facility between January 1, 2019, and March 16, 2020, were collected. Patients were categorized into three groups based on length of stay: (1) AMS, (2) OS, or (3) inpatient. Demographics, comorbidities, surgical information, and administrative information were collected. Simple and multivariable logistic regression analyses were conducted comparing AMS patients and OS/inpatient as well as OS and inpatients. RESULTS: Of the 1096 patients, 641 (58%) patients were converted to either OS (n=486) or inpatient (n=155). The multivariable analysis demonstrated that age (more than 80 yr old), high American Society of Anesthesiologists Physical Status (ASA) grade, history of sleep apnea, drain use, high estimated blood loss, long operation, late operation start time, and a high pain score were considered independent risk factors for AMS conversion to OS/inpatient. The risk factors for OS conversion to inpatient were an ASA class 3 or higher, coronary artery disease, diabetes mellitus, hypothyroidism, steroid use, drain use, dural tear, and laminectomy. CONCLUSIONS: Several surgical factors along with patient-specific factors were significantly associated with AMS conversion. Addressing modifiable surgical factors might reduce the AMS conversion rate and be beneficial to patients and facilities.

Comparative effectiveness of anesthetic technique on outcomes after lumbar spine surgery: a retrospective propensity score-matched analysis of the National Surgical Quality Improvement Program, 2009-2019.

BACKGROUND: The impact of anesthetic technique on spine surgery outcomes is controversial. Using a large national sample of patients, we compared outcomes after lumbar decompression under regional anesthesia (RA: spinal or epidural) or general anesthesia (GA). METHODS: A retrospective population-based study of American College of Surgeons National Surgical Quality Improvement Program data (2009-2019). Patients were propensity score (PS) matched 3:1 (GA:RA) on demographic and surgical variables. The primary outcome was the association between anesthetic type and any complication (cardiac, pulmonary, renal, transfusion, stroke, infectious, deep vein thrombosis/pulmonary embolus). Secondary outcomes included the association between anesthetic type and individual complications, readmission and length of stay (LOS). Unadjusted comparisons (OR, 95% CI), logistic regression and adjusted generalized linear modeling (parameter estimate, PE, 95% CI) were performed before and after PS matching. RESULTS: Of 1 51 010 cases, 149 996 (99.3%) were performed under GA, and 1014 (0.67%) under RA. After matching, 3042 patients with GA were compared with 1014 patients with RA. On unadjusted analyses, RA was associated with lower odds of complications (OR 0.43, 0.3 to 0.6, p<0.001), shorter LOS (RA: 1.1±3.8 days vs GA: 1.3±3.0 days; p<0.001) and fewer blood transfusions (RA: 3/1014, 0.3% vs GA: 40/3042, 1.3%; p=0.004). In adjusted analyses, RA was associated with fewer complications (PE -0.43, -0.81 to -0.06, p=0.02) and shorter LOS (PE -0.76, -0.90 to -0.63, p<0.001). There was no significant association between anesthetic type and readmission (PE -0.34, -0.74 to 0.05, p=0.09). CONCLUSIONS: Compared with GA, RA was associated with fewer complications, less blood transfusion and shorter LOS after spine surgery. Although statistically significant, the magnitude of effects was small and requires further prospective study.

The predictive value of psoas and paraspinal muscle parameters measured on MRI for severe cage subsidence after standalone lateral lumbar interbody fusion.

BACKGROUND CONTEXT: The effect of psoas and paraspinal muscle parameters on cage subsidence after minimally invasive techniques, such as standalone lateral lumbar interbody fusion (SA-LLIF), is unknown. PURPOSE: This study aimed to determine whether the functional cross-sectional area (FCSA) of psoas and lumbar spine extensor muscles (multifidus and erector spinae), and psoas FCSA normalized to the vertebral body area (FCSA/VBA) differ among levels with severe cage subsidence after SA-LLIF when compared to levels without severe cage subsidence. STUDY DESIGN: Retrospective single center cohort study. PATIENT SAMPLE: Patients who underwent SA-LLIF between 2008 and 2020 for degenerative conditions using exclusively polyetheretherketone (PEEK) cages, had a lumbar magnetic resonance imaging (MRI) scan within 12 months, a lumbar computed tomography (CT) scan within 6 months prior to surgery, and a postoperative clinical and radiographic follow-up at a minimum of 6 months were included. OUTCOME MEASURES: Severe cage subsidence. METHODS: MRI measurements included psoas and combined multifidus and erector spinae (paraspinal) FCSA and FCSA/VBA at the L3-L5 pedicles. Following manual segmentation of muscles on axial T2-weighted images using ITK-SNAP (version 3.8.0), the FCSA was calculated using a custom written program on Matlab (version R2019a, The MathWorks, Inc.) that used an automated pixel intensity threshold method to differentiate between fat and muscle. Mean volumetric bone mineral density (vBMD) at L1/2 was measured by quantitative CT. The primary endpoint was severe cage subsidence per level according to the classification by Marchi et al. Multivariable logistic regression analysis was performed using generalized linear mixed models. All analyses were stratified by biological sex. RESULTS: 95 patients (45.3% female) with a total of 188 operated levels were included in the analysis. The patient population was 92.6% Caucasian with a median age at surgery of 65 years. Overall subsidence (Grades 0-III) was 49.5% (53/107 levels) in men versus 58.0% (47/81 levels) in women (p=.302), and severe subsidence (Grades II-III) was 22.4% (24/107 levels) in men versus 25.9% (21/81 levels) in women (p=.608). In men, median psoas FCSA and psoas FCSA/VBA at L3 and L4 were significantly greater in the severe subsidence group when compared to the non-severe subsidence group. No such difference was observed in women. Paraspinal muscle parameters did not differ significantly between non-severe and severe subsidence groups for both sexes. In the multivariable logistic regression analysis with adjustments for vBMD and cage length, psoas FCSA at L3 (OR 1.002; p=.020) and psoas FCSA/VBA at L3 (OR 8.655; p=.029) and L4 (OR 4.273; p=.043) were found to be independent risk factors for severe cage subsidence in men. CONCLUSIONS: Our study demonstrated that greater psoas FCSA at L3 and psoas FCSA/VBA at L3 and L4 were independent risk factors for severe cage subsidence in men after SA-LLIF with PEEK cages. The higher compressive forces the psoas exerts on lumbar segments as a potential stabilizer might explain these findings. Additional pedicle screw fixation might be warranted in these patients to avoid severe cage subsidence.

Atypical femoral fracture mimicking lumbar radiculopathy in two patients taking bisphosphonate long-term: A case report.

BACKGROUND: Atypical femoral fracture (AFF) is a rare complication in patients with osteoporosis undergoing long-term bisphosphonate therapy. The most common symptom of incomplete AFF is nonspecific thigh pain, which is often difficult to distinguish from other causes. CASE PRESENTATION: We present two cases of AFF misdiagnosed as lumbar radiculopathy. Both patients visited our hospital for thigh pain, and in both cases the findings of lumbar spine magnetic resonance imaging showed substantial nerve compression. These patients had been treated for lumbar radiculopathy, but localized symptoms became conspicuous and femoral radiographs revealed complete AFF. The initial radiographs were reviewed retrospectively and revealed slight lateral cortical thickening in the affected femur, denoting a missed incomplete AFF. Internal fixation with intramedullary nails was performed. CONCLUSIONS: AFF may mimic lumbar radiculopathy. Therefore, clinicians should consider AFF as a differential diagnosis in older patients with lumbar canal stenosis who are undergoing long-term bisphosphonate therapy and present with thigh pain.