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Background: The modified frailty index (mFI-5) has been shown to be a reliable risk stratification tool in different spine procedures. Its usefulness to predict complications after 1-level or 2-level anterior cervical decompression and fusion (ACDF) has not been studied extensively., Purpose: We aimed to assess the usefulness of the mFI-5 in 1-level or 2-level ACDF surgery by asking the following questions: (1) Is the mFI-5 a reliable tool to predict complications after 1-level or 2-level ACDF? (2) Is the mFI-5 useful in predicting prolonged hospital stay after 1-level or 2-level ACDF? (3) Is the mFI-5 useful in predicting readmission after 1-level or 2-level ACDF?, Methods: We performed a retrospective analysis of the medical records of patients who underwent 1-level or 2-level ACDF at our institution. The mFI-5 was calculated based on the presence of 5 comorbidities: (1) congestive heart failure, (2) diabetes mellitus, (3) chronic obstructive pulmonary disease, (4) partially or totally dependent functional status, and (5) hypertension requiring medication. Patients were classified in 3 groups: not frail (mFI-5 items = 0), pre-frail (mFI-5 items = 1), and frail (mFI-5 items ≥2). Postoperative complications, length of stay, and readmission were recorded., Results: In the 662 patients included (mean age 51.4 ± 10.4 years), surgical and medical complications were not significantly different among groups. Lengths of stay and readmission rates were both significantly higher in the pre-frail group., Conclusion: Our study findings suggest that the mFI-5 might not be reliable to assess preoperative risk after 1-level or 2-level ACDF., Competing Interests: The author(s) declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: Gbolabo Sokunbi, MD, reports relationships with Stryker and Camber Spine. Alexander P. Hughes, MD, reports relationships with Kuros Biosciences AG, NuVasive, Inc., and Kuros Biosciences BV. Federico P. Girardi, MD, reports relationships with Lanx, Inc., Ortho Development Corp., BCIMD, and Healthpoint Capital Partners, LP. Frank P. Cammisa, MD, reports relationships with NuVasive, Inc., Accelus, 4WEB Medical/4WEB, Inc., Healthpoint Capital Partners, LP; ISPH II, LLC; ISPH 3 Holdings, LLC; Ivy Healthcare Capital Partners, LLC; Medical Device Partners II, LLC; Medical Device Partners III, LLC; Orthobond Corporation; Spine Biopharma, LLC; Tissue Differentiation Intelligence, LLC; VBVP VI, LLC; VBVP X, LLC; Woven Orthopedics Technologies; DePuy Synthes, Spine Biopharma, LLC, Mallinckrodt Pharmaceuticals, Camber Spine, and Centinel Spine. Andrew. A. Sama, MD, reports relationships with Ortho Development, Corp., Vestia Ventures MiRUS Investment, LLC, IVY II, LLC, ISPH II, LLC, ISPH 3, LLC, HSS ASC Development Network, LLC, Centinel Spine (Vbros Venture Partners V), Depuy Synthes Products, Inc., Clariance, Inc., Kuros Biosciences AG, Ortho Development Corp., and Spinal Kinetics, Inc. The other authors declared no potential conflicts of interest., (© The Author(s) 2024.)

Purpose: Computed tomography (CT) scans are widely used clinically in the diagnosis of ossification of the posterior longitudinal ligament (OPLL). Conventionally acquired magnetic resonance imaging (MRI) is limited by insufficient signal intensity within bone tissue. Osseus conspicuity may be enhanced by applying sequences with "CT-like" bone contrast zero-echo time (ZTE) MRI. This is a case series aimed to understand if ZTE-MRI is sensitive in detecting cervical OPLL and if this modality is suitable for evaluating OPLL morphology., Methods: A retrospective review was performed to identify adult patients with available cervical ZTE-MRI and CT scans. ZTE-MRI and CT were evaluated for their ability to detect OPLL by 2 attending spine surgeons, 1 spine surgery clinical fellow, and 1 senior orthopedic resident. The phenotype of OPLL was then described and compared between the two modalities., Results: A total of 50 patients were reviewed. All clinicians detected 4 cases of OPLL on CT, and the same cases were independently found on ZTE-MRI. The modalities were then compared to assess the phenotype of OPLL., Conclusion: ZTE-MRI may have the potential to obviate the need for concurrent CT scans in diagnosing OPLL. When OPLL was suspected on MRI, ZTE-MRI could confirm the OPLL diagnosis. With conventional MRI sequences that include additional post-processed ZTE-MRI, clinicians can also assess OPLL morphology and the resulting spinal cord change to make a complete diagnosis and identify patients at higher risk for progression or complications. ZTE-MRI avoids CT-related radiation, can improve diagnosis, and decrease health costs., Competing Interests: Declarations. Conflict of interest: The authors have no relevant financial or non-financial interests to disclose. Dr. Carrino reports consulting for Pfizer, Inc; Eli-Lilly; Globus Medical, Inc.; Regeneron; AstraZeneca; scientific advisory board/other office position with Carestream; Image Analysis Group; Image Biopsy Lab. Dr. Hughes reports research support from Kuros Biosciences AG and Expanding Innovations, Inc.; private investments in Tissue Connect Systems, Inc.; and fellowship support from NuVasive, Inc. outside the submitted work. Ethics approval: This retrospective chart review study involving human participants was in accordance with the ethical standards of the institutional and national research committee and with the 1964 Helsinki Declaration and its later amendments or comparable ethical standards. The Institutional Review Board (IRB) of Hospital for Special Surgery approved this study (#2023–0413). Consent to Participate and Publish: Informed consent was waived due to the retrospective nature of the study., (© 2024. The Author(s), under exclusive licence to Springer-Verlag France SAS, part of Springer Nature.)

Introduction The aim of this study was to investigate whether the morphology of the acromion and the inclination of the glenoid are associated with the risk of supraspinatus (SSP) tendon ruptures. Materials and methods A total of 106 patients were enrolled in this study between August 2012 and February 2014, including 55 symptomatic patients with an SSP tendon rupture (ruptured group) and 51 patients with an intact SSP (control group). MRI of the shoulder was performed for all patients in both groups. All MR images were analyzed by two blinded observers to measure the acromiohumeral interval (AHI), critical shoulder angle (CSA), acromial slope (AS), acromial tilt (AT), lateral acromial angle (LAA), acromion index (AI), and glenoid inclination (GI). Furthermore, both observers analyzed tendon integrity and quality on all MRIs in both groups. The results of the radiological examination concerning acromial and glenoidal morphology were compared between the control group with intact SSP tendons and the rupture group. Results Patients with an SSP tendon rupture had a narrower AHI (9.1 ± 1.4 mm vs. 7.8 ± 2.1 mm; p < 0.01), a greater AT (36.0 ± 5.4° vs. 39.7 ± 5.9°; p < 0.01), and a lower LAA (81.1 ± 7.2° vs. 76.2 ± 5.0°; p < 0.01). Patients with an AHI smaller than 8.2 mm (OR 1.88 [95% CI 1.2 to 2.7]; p < 0.01) or an AT greater than 36.5° (OR 3.56 [95% CI 1.57 to 8.01]; p = 0.03) or a LAA lower than 80.5° (OR 4.04 [95% CI 2.04 to 7.90]; p < 0.01) had higher risk for an SSP tendon rupture. No differences between either group were found in relation to the AS, CSA, AI, or glenoid inclination. Conclusions The results of this study showed that the AHI, LAA and AT correlated with SSP tendon rupture. It should be noted that the preoperative AHI less than 8.2 mm, AT greater than 36.5° or LAA less than 80.5° may be associated with SSP tendon ruptures., Competing Interests: Human subjects: Consent for treatment and open access publication was obtained or waived by all participants in this study. University of Ulm issued approval 104/17. Animal subjects: All authors have confirmed that this study did not involve animal subjects or tissue. Conflicts of interest: In compliance with the ICMJE uniform disclosure form, all authors declare the following: Payment/services info: All authors have declared that no financial support was received from any organization for the submitted work. Financial relationships: All authors have declared that they have no financial relationships at present or within the previous three years with any organizations that might have an interest in the submitted work. Other relationships: All authors have declared that there are no other relationships or activities that could appear to have influenced the submitted work., (Copyright © 2024, Caffard et al.)

Study Design: Retrospective cohort study., Objectives: To identify imaging predictors on pre- and perioperative imaging that are associated with a future revision surgery for adjacent segment disease (ASD) following lumbar fusion., Methods: Patients undergoing open posterior lumbar fusion between 2014-2022 were followed-up for >2-year. The initial MRI was evaluated for disc degeneration by Pfirrmann (grade 1-5); Modic changes (0-3); as well as fatty infiltration and functional cross-sectional area (fCSA) of the multifidus, erector spinae, and psoas. Spinopelvic alignment was measured pre- and postoperatively., Results: Of 216 patients, 14.8% (n = 32) required revision surgery for ASD in the further course. There were no significant differences in Modic changes or Pfirrmann grades between the ASD group and controls. Fatty infiltration was significantly higher in the ASD group for both the erector spinae (40.5% vs 36.9%, P = 0.043) and multifidus muscles (61.0% vs 53.9%, P = 0.003). Additionally, the multifidus fCSA was smaller in patients who developed ASD (5.7 cm 2 vs 6.7 cm 2 ). Pre- and postoperative spinopelvic parameters were not significantly different between groups, and no other MRI measurements showed a significant difference. In a multivariable logistic regression model adjusting for age and sex, multifidus fatty infiltration emerged as the only significant predictor of ASD revision surgery ( P = 0.004). Patients with more than 58% multifidus fatty infiltration had over double the risk of developing ASD (OR 2.7, 95% CI: 1.1-6.5, P = 0.032)., Conclusions: Multifidus fatty infiltration is the key imaging predictor for the development of ASD requiring surgical revision. Disc degeneration and spinopelvic alignment appear to have less impact., Competing Interests: Declaration of Conflicting InterestThe author(s) declared the following potential conflicts of interest with respect to the research, authorship, and/or publication of this article: AAS reports royalties from Ortho Development, Corp. DePuy Spine Products/Medical Device Business Services, Clariance, Inc.; private investments for Vestia Ventures MiRUS Investment, LLC, ISPH II, LLC, ISPH 3, LLC, and Centinel Spine (Vbros Venture Partners V); consulting fees from DePuy Spine Products/Medical Device Business Services, Clariance, Inc., Kuros Biosciences AG; speaking and/or teaching arrangements for DePuy Spine Products/Medical Device Business Services; membership of scientific advisory board of DePuy Spine Products/Medical Device Business Services, Kuros Biosciences AG, Clariance, Inc., and research support from Spinal Kinetics, Inc./Orthofix, Inc., outside the submitted work. FPC reports royalties from Accelus; ownership interest for 4WEB Medical/4WEB, Inc.; Healthpoint Capital Partners, LP; ISPH II, LLC; ISPH 3 Holdings, LLC; Ivy Health care Capital Partners, LLC; Medical Device Partners II, LLC; Medical Device Partners III, LLC; Orthobond Corporation; Spine Biopharma, LLC; Tissue Differentiation Intelligence, LLC; Tissue Connect Systems, Inc.; VBVP VI, LLC; VBVP X, LLC; Woven Orthopedics Technologies; consulting fees from Spine Biopharma, LLC, and Accelus; membership of scientific advisory board/other office of Healthpoint Capital Partners, Medical Device Partners II, LLC, Orthobond Corporation, Spine Biopharma, LLC, and Woven Orthopedic Technologies; and research support from 4WEB Medical/4WEB, Inc., Camber Spine, Choice Spine, DePuy Synthes, Centinel Spine, and Royal Biologics outside the submitted work. FPG reports royalties from Lanx, Inc. And Ortho Development Corp.; ownership interest in Centinel Spine, BICMD; consulting fees from Lanx, Inc, Ortho Development Corp, and Sea Spine;and stock ownership in Centinel Spine, Healthpoint Capital Partners, LP; membership of scientific advisory board/other office of Healthpoint Capital Partners, outside the submitted work. APH reports research support from Kuros Biosciences AG and Expanding Innovations, Inc.; private investments in Tissue Connect Systems, Inc.; and fellowship support from NuVasive, Inc., Globus Medical North America, Inc., and Alphatec Spine, Inc., outside the submitted work.

Introduction While several studies have compared tenotomy and tenodesis, few studies have examined whether performing a tenodesis of the long head of the biceps (LHB), when indicated, in patients who have undergone rotator cuff reconstruction has a detrimental impact on clinical and radiological postoperative outcomes. The present study aimed to investigate whether performing a tenodesis of the LHB has a damaging effect on the clinical and radiological outcome after rotator cuff reconstruction. Material and methods Fifty-one patients surgically treated for supraspinatus (SSP) tendon tears were included. All included patients received a reconstruction of the SSP, depending on the LHB surgery performed, patients were divided into two groups: 1) with concomitant tenodesis of the LHB and 2) without surgery of the LHB. Western Ontario Rotator Cuff Index (WORC), American Shoulder and Elbow Surgeons Shoulder Score (ASES), Constant, Oxford, and LHB scores were assessed at 2.3 ± 0.3 years postoperatively. All patients underwent clinical examination, including range of motion and force measurements. Furthermore, patients received an MRI scan of the operated shoulder two years postoperatively. Two blinded observers independently analyzed the integrity and quality of the rotator cuff on postoperative MRI using Sugaya and Castricini classifications. Clinical and radiological results were compared between both groups. Results All analyzed clinical scores, ranges of motion, and force measurements revealed no difference between both groups. Except for fatty infiltration (0° = 81% (21 of 26) vs. 68% (17 of 25); 1° = 15% (four of 26) vs. 28% (seven of 25); 2° = 4% (one of 26) vs. 4% (one of 25); and 3° = 0% (0 of 26) vs. 4% (one of 25); p < 0.01), no differences between both groups concerning the integrity (re-rupture rate = 27% (seven of 26) vs. 20% (five of 25); p = 0.39) and quality of the SSP tendon were found. Conclusions Tenodesis of the LHB performed in addition to rotator cuff repair is not associated with detrimental clinical outcomes than rotator cuff repair without surgery of the LHB. Except for fatty infiltration, which was lower in the tenodesis group, the results of the present study suggest that concomitant tenodesis of the LHB produces in patients who received rotator cuff repair have no detrimental effect in terms of clinical outcomes and re-rupture rates as well as tendon quality. Therefore, when indicated, simultaneous tenodesis of the LHB appears to be a safe and effective procedure that has no negative impact on the postoperative outcome after SSP tendon reconstruction., Competing Interests: Human subjects: Consent for treatment and open access publication was obtained or waived by all participants in this study. Institutional Review Board of University of Ulm issued approval 155/19. Animal subjects: All authors have confirmed that this study did not involve animal subjects or tissue. Conflicts of interest: In compliance with the ICMJE uniform disclosure form, all authors declare the following: Payment/services info: All authors have declared that no financial support was received from any organization for the submitted work. Financial relationships: All authors have declared that they have no financial relationships at present or within the previous three years with any organizations that might have an interest in the submitted work. Other relationships: All authors have declared that there are no other relationships or activities that could appear to have influenced the submitted work., (Copyright © 2024, Sgroi et al.)

Purpose: The literature is scarce in exploring the role of imaging parameters like ultrasound (US) as a biomarker for surgical outcomes. The purpose of this study is to investigate the associations between skin US parameters and revision surgery following spine lumbar fusion., Methods: Posterior lumbar fusion patients with 2-years follow-up were assessed. Previous fusion or revision not due to adjacent segment disease (ASD) were excluded. Revisions were classified as cases and non-revision were classified as controls. US measurements conducted at two standardized locations on the lumbar back. Skin echogenicity of the average dermal (AD), upper 1/3 of the dermal (UD), lower 1/3 of the dermal (LD), and subcutaneous layer were measured. Echogenicity was calculated with the embedded echogenicity function of our institution's imaging platform (PACS). Statistical significance was set at p < 0.05., Results: A total of 128 patients (51% female, age 62 [54-72] years) were included in the final analysis. 17 patients required revision surgery. AD, UD, and LD echogenicity showed significantly higher results among revision cases 124.5 [IQR = 115.75,131.63], 128.5 [IQR = 125,131.63] and 125.5 [IQR = 107.91,136.50] compared to the control group 114.3 [IQR = 98.83,124.8], 118.5 [IQR = 109.28,127.50], 114 [IQR = 94.20,126.75] respectively., Conclusion: The findings of this study demonstrate a significant association between higher echogenicity values in different layers of the dermis and requiring revision surgery. The results provide insights into the potential use of skin US parameters as predictors for revision surgery. These findings may reflect underlying alterations in collagen. Further research is warranted to elucidate the mechanisms driving these associations., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Paraspinal muscle atrophy is gaining attention in spine surgery due to its link to back pain, spinal degeneration and worse postoperative outcomes. Electrical impedance myography (EIM) is a noninvasive diagnostic tool for muscle quality assessment, primarily utilized for patients with neuromuscular diseases. However, EIM's accuracy for paraspinal muscle assessment remains understudied. In this study, we investigated the correlation between EIM readings and MRI-derived muscle parameters, as well as the influence of dermal and subcutaneous parameters on these readings. We retrospectively analyzed patients with lumbar spinal degeneration who underwent paraspinal EIM assessment between May 2023 to July 2023. Paraspinal muscle fatty infiltration (FI) and functional cross-sectional area (fCSA), as well as the subcutaneous thickness were assessed on MRI scans. Skin ultrasound imaging was assessed for dermal thickness and the echogenicities of the dermal and subcutaneous layers. All measurements were performed on the bilaterally. The correlation between EIM readings were compared with ultrasound and MRI parameters using Spearman's correlation analyses. A total of 20 patients (65.0% female) with a median age of 69.5 years (IQR, 61.3-73.8) were analyzed. The fCSA and FI did not significantly correlate with the EIM readings, regardless of frequency. All EIM readings across frequencies correlated with subcutaneous thickness, echogenicity, or dermal thickness. With the current methodology, paraspinal EIM is not a valid alternative to MRI assessment of muscle quality, as it is strongly influenced by the dermal and subcutaneous layers. Further studies are required for refining the methodology and confirming our results., (© 2024 Orthopaedic Research Society.)

Study Design: Retrospective cross-sectional study., Objective: To evaluate the relationship between lumbar foraminal stenosis (LFS) and multifidus muscle atrophy., Background: The multifidus muscle is an important stabilizer of the lumbar spine. In LFS, the compression of the segmental nerve can give rise to radicular symptoms and back pain. LFS can impede function and induce atrophy of the segmentally innervated multifidus muscle., Methods: Patients with degenerative lumbar spinal conditions who underwent posterior spinal fusion for degenerative lumbar disease from December 2014 to February 2024 were analyzed. Multifidus fatty infiltration (FI) and functional cross-sectional area (fCSA) were determined at the L4 upper endplate axial level on T2- weighted MRI scans using dedicated software. Severity of LFS was assessed at all lumbar levels and sides using the Lee classification (Grade: 0 - 3). For each level, Pfirrmann and Weishaupt gradings were used to assess intervertebral disc disease (IVDD) and facet joint osteoarthritis (FJOA), respectively. Multivariable linear mixed models were run for the LFS grade of each level and side separately as the independent predictor of multifidus FI and fCSA. Each analysis was adjusted for age, sex, BMI, as well as FJOA and IVDD of the level corresponding to the LFS., Results: A total of 216 patients (50.5% female) with a median age of 61.6 years (IQR=52.0 - 69.0) and a median BMI of 28.1 kg/m2 (IQR=24.8 - 33.0) were included. Linear mixed model analysis revealed that higher multifidus FI (Estimate [Confidence interval]=1.7% [0.1 - 3.3], P=0.043) and lower fCSA (-18.6 mm2 [-34.3 - -2.6], P=0.022) were both significantly predicted by L2-L3 level LFS severity., Conclusion: The observed positive correlation between upper segment LFS and multifidus muscle atrophy points towards compromised innervation. This necessitates further research to establish the causal relationship and guide prevention efforts., Competing Interests: Declaration of conflicting interest: The Authors declare that there is no conflict of interest concerning materials or methods used in this study or the findings specified in this paper., (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)

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., 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 degenerative lumbar spondylolisthesis undergoing decompression and fusion surgery were analyzed. Patients with missing follow-up, no imaging, or inadequate image quality were excluded. The ODI was assessed preoperatively and two years postoperatively. A cross-sectional area of the PM was measured on a T2-weighted magnetic resonance imaging sequence at the upper endplate of L4. On the basis of the literature, a 10-point improvement cutoff was defined as the minimum clinically important difference. Patients with a baseline ODI below the minimum clinically important difference 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., Results: A total of 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 <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 after decompression and fusion. Further research is needed to assess the effect of interventions., Competing Interests: A.A.S. reports royalties from Ortho Development, Corp.; private investments for Vestia Ventures MiRUS Investment, LLC, IVY II, LLC, ISPH II, LLC, ISPH 3, LLC, HS2, LLC, HSS ASC Development Network, LLC, and Centinel Spine (Vbros Venture Partners V); consulting fee from Depuy Synthes Products Inc., Clariance Inc., Kuros Biosciences AG, Ortho Development Corp., Medical Device Business Service Inc.; speaking and teaching arrangements of DePuy Synthes Products Inc.; membership of scientific advisory board of Depuy Synthes Products Inc., Clariance Inc., and Kuros Biosciences AG; Medical Device Business Service Inc. and trips/travel of Medical Device Business; research support from Spinal Kinetics Inc., outside the submitted work. Cammisa reports royalties from NuVasive Inc. Accelus; ownership interest for 4WEB Medical/4WEB Inc.; Healthpoint Capital Partners, LP; ISPH II, LLC; ISPH 3 Holdings, LLC; Ivy Healthcare Capital Partners, LLC; Medical Device Partners II, LLC; Medical Device Partners III, LLC; Orthobond Corporation; Spine Biopharma, LLC; Tissue Differentiation Intelligence, LLC; VBVP VI, LLC; VBVP X, LLC; Woven Orthopedics Technologies; consulting fees from 4WEB Medical/4WEB Inc., DePuy Synthes, NuVasive Inc., Spine Biopharma, LLC, and Synexis, LLC, Accelus; membership of scientific advisory board/other office of Healthpoint Capital Partners, Medical Device Partners II, LLC, Orthobond Corporation, Spine Biopharma, LLC, and Woven Orthopedic Technologies; and research support from 4WEB Medical/4WEB Inc., Mallinckrodt Pharmaceuticals, Camber Spine, and Centinel Spine, outside the submitted work. F.P.G. reports royalties from Lanx Inc., and Ortho Development Corp.; private investments for BCIMD; and stock ownership of Healthpoint Capital Partners, LP, outside the submitted work. A.P.H. reports research support from Kuros Biosciences AG and fellowship support from NuVasive Inc. and Kuros Biosciences BV, outside the submitted work. The remaining authors report no conflicts of interest., (Copyright © 2023 Wolters Kluwer Health, Inc. All rights reserved.)

Background Context: Atrophy of the paraspinal musculature (PM) as well as generalized sarcopenia are increasingly reported as important parameters for clinical outcomes in the field of spine surgery. Despite growing awareness and potential similarities between both conditions, the relationship between "generalized" and "spine-specific" sarcopenia is unclear., Purpose: To investigate the association between generalized and spine-specific sarcopenia., Study Design: Retrospective cross-sectional study., Patient Sample: Patients undergoing lumbar spinal fusion surgery for degenerative spinal pathologies., Outcome Measures: Generalized sarcopenia was evaluated with the short physical performance battery (SPPB), grip strength, and the psoas index, while spine-specific sarcopenia was evaluated by measuring fatty infiltration (FI) of the PM., Methods: We used custom software written in MATLAB® to calculate the FI of the PM. The correlation between FI of the PM and assessments of generalized sarcopenia was calculated using Spearman's rank correlation coefficient (rho). The strength of the correlation was evaluated according to established cut-offs: negligible: 0-0.3, low: 0.3-0.5, moderate: 0.5-0.7, high: 0.7-0.9, and very high≥0.9. In a Receiver Operating Characteristics (ROC) analysis, the Area Under the Curve (AUC) of sarcopenia assessments to predict severe multifidus atrophy (FI≥50%) was calculated. In a secondary analysis, factors associated with severe multifidus atrophy in nonsarcopenic patients were analyzed., Results: A total of 125 (43% female) patients, with a median age of 63 (IQR 55-73) were included. The most common surgical indication was lumbar spinal stenosis (79.5%). The median FI of the multifidus was 45.5% (IQR 35.6-55.2). Grip strength demonstrated the highest correlation with FI of the multifidus and erector spinae (rho=-0.43 and -0.32, p<.001); the other correlations were significant (p<.05) but lower in strength. In the AUC analysis, the AUC was 0.61 for the SPPB, 0.71 for grip strength, and 0.72 for the psoas index. The latter two were worse in female patients, with an AUC of 0.48 and 0.49. Facet joint arthropathy (OR: 1.26, 95% CI: 1.11-1.47, p=.001) and foraminal stenosis (OR: 1.54, 95% CI: 1.10-2.23, p=.015) were independently associated with severe multifidus atrophy in our secondary analysis., Conclusion: Our study demonstrates a low correlation between generalized and spine-specific sarcopenia. These findings highlight the risk of misdiagnosis when relying on screening tools for general sarcopenia and suggest that general and spine-specific sarcopenia may have distinct etiologies., Competing Interests: Declaration of competing interest One or more of the authors declare financial or professional relationships on ICMJE-TSJ disclosure forms., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Objective: The paraspinal muscles play an essential role in the stabilization of the lumbar spine. Lumbar paraspinal muscle atrophy has been linked to chronic back pain and degenerative processes within the spinal motion segment. However, the relationship between the different paraspinal muscle groups and facet joint osteoarthritis (FJOA) has not been fully explored., Methods: In this cross-sectional study, the authors analyzed adult patients who underwent lumbar spinal surgery between December 2014 and March 2023 for degenerative spinal conditions and had preoperative MRI and CT scans. The fatty infiltration (FI) and functional cross-sectional area (fCSA) of the psoas, erector spinae, and multifidus muscles were assessed on axial T2-weighted MR images at the level of the upper endplate of L4 based on established studies and calculated using custom-made software. Intervertebral disc degeneration at each lumbar level was evaluated using the Pfirrmann grading system. The grades from each level were summed to report the cumulative lumbar Pfirrmann grade. Weishaupt classification (0-3) was used to assess FJOA at all lumbar levels (L1 to S1) on preoperative CT scans. The total lumbar FJOA score was determined by adding the Weishaupt grades of both sides at all 5 levels. Correlation and linear regression analyses were conducted to assess the relationship between FJOA and paraspinal muscle parameters., Results: A total of 225 patients (49.7% female) with a median age of 61 (IQR 54-70) years and a median BMI of 28.3 (IQR 25.1-33.1) kg/m2 were included. After adjustment for age, sex, BMI, and the cumulative lumbar Pfirrmann grade, only multifidus muscle fCSA (estimate -4.69, 95% CI -6.91 to -2.46; p < 0.001) and FI (estimate 0.64, 95% CI 0.33-0.94; p < 0.001) were independently predicted by the total FJOA score. A similar relation was seen with individual Weishaupt grades of each lumbar level after controlling for age, sex, BMI, and the Pfirrmann grade of the corresponding level., Conclusions: Atrophy of the multifidus muscle is significantly associated with FJOA in the lumbar spine. The absence of such correlation for the erector spinae and psoas muscles highlights the unique link between multifidus muscle quality and the degeneration of the spinal motion segment. Further research is necessary to establish the causal link and the clinical implications of these findings.

Objective: There are limited data about the influence of the lumbar paraspinal muscles on the maintenance of sagittal alignment after pedicle subtraction osteotomy (PSO) and the risk factors for sagittal realignment failure. The authors aimed to investigate the influence of preoperative lumbar paraspinal muscle quality on the postoperative maintenance of sagittal alignment after lumbar PSO., Methods: Patients who underwent lumbar PSO with preoperative lumbar MRI and pre- and postoperative whole-spine radiography in the standing position were included. Spinopelvic measurements included pelvic incidence, sacral slope, pelvic tilt, L1-S1 lordosis, T4-12 thoracic kyphosis, spinosacral angle, C7-S1 sagittal vertical axis (SVA), T1 pelvic angle, and mismatch between pelvic incidence and L1-S1 lordosis. Validated custom software was used to calculate the percent fat infiltration (FI) of the psoas major, as well as the erector spinae and multifidus (MF). A multivariable linear mixed model was applied to further examine the association between MF FI and the postoperative progression of SVA over time, accounting for repeated measures over time that were adjusted for age, sex, BMI, and length of follow-up., Results: Seventy-seven patients were recruited. The authors' results demonstrated significant correlations between MF FI and the maintenance of corrected sagittal alignment after PSO. After adjustment for the aforementioned parameters, the model showed that the MF FI was significantly associated with the postoperative progression of positive SVA over time. A 1% increase from the preoperatively assessed total MF FI was correlated with an increase of 0.92 mm in SVA postoperatively (95% CI 0.42-1.41, p < 0.0001)., Conclusions: This study included a large patient cohort with midterm follow-up after PSO and emphasized the importance of the lumbar paraspinal muscles in the maintenance of sagittal alignment correction. Surgeons should assess the quality of the MF preoperatively in patients undergoing PSO to identify patients with severe FI, as they may be at higher risk for sagittal decompensation.

Study Design: Retrospective cohort study., Objective: To analyze the relationship of abdominal aortic calcification (AAC) and a reduction in the cross-sectional area (CSA) and the fatty infiltration (FI) of the paravertebral muscles in patients undergoing lumbar fusion surgery., Background: Both AAC and paraspinal muscle degeneration have been shown to be associated with poorer outcomes after surgical treatment of degenerative diseases of the lumbar spine. However, there is a lack of data on the association between AAC and paraspinal muscle changes in patients undergoing spine surgery., Methods: We retrospectively analyzed patients undergoing lumbar fusion for degenerative spinal pathologies. Muscular and spinal degeneration were measured on magnetic resonance imaging (MRI). AAC was classified on lateral lumbar radiographs. The association of AAC and paraspinal muscle composition was assessed by a multivariate regression analysis adjusted for age, sex, body mass index (BMI), comorbidities, and lumbar degeneration., Results: A total of 301 patients was included. Patients with AAC showed significantly higher degrees of intervertebral disc and facet joint degeneration as well as higher total endplate scores at the L3/4 level. The univariable regression analysis showed a significant positive correlation between the degree of AAC and the FI of the erector spinae (b=0.530, P<0.001) and multifidus (b=0.730, P<0.001). The multivariable regression analysis showed a significant positive correlation between the degree of AAC and the FI of the erector spinae (b=0.270, P=0.006) and a significant negative correlation between the degree of AAC and the CSA of the psoas muscle (b=-0.260, P=0.003)., Conclusion: This study demonstrates a significant and independent association between AAC and degeneration of the erector spinae and the psoas muscles in patients undergoing lumbar fusion. As both AAC and degeneration of paraspinal muscles impact postoperative outcomes negatively, preoperative assessment of AAC may aid in identifying patients at higher risk after lumbar surgery., Competing Interests: Declaration of Conflicting Interest: The Authors declare that there is no conflict of interest concerning materials or methods used in this study or the findings specified in this paper., (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)

Objective: The aim of this study was to investigate the influence of preoperatively assessed paraspinal muscle parameters on postoperative patient-reported outcomes and maintenance of cervical sagittal alignment after anterior cervical discectomy and fusion (ACDF)., Methods: Patients with preoperative and postoperative standing cervical spine lateral radiographs and preoperative cervical MRI who underwent an ACDF between 2015 and 2018 were reviewed. Muscles from C3 to C7 were segmented into 4 functional groups: anterior, posteromedial, posterolateral, and sternocleidomastoid. The functional cross-sectional area and also the percent fat infiltration (FI) were calculated for all groups. Radiographic alignment parameters collected preoperatively and postoperatively included C2-7 lordosis and C2-7 sagittal vertical axis (SVA). Neck Disability Index (NDI) scores were recorded preoperatively and at 2 and 4-6 months postoperatively. To investigate the relationship between muscle parameters and postoperative changes in sagittal alignment, multivariable linear mixed models were used. Multivariable linear regression models were used to analyze the correlations between the changes in NDI scores and the muscles' FI., Results: A total of 168 patients with NDI and 157 patients with sagittal alignment measurements with a median follow-up of 364 days were reviewed. The mixed models showed that a greater functional cross-sectional area of the posterolateral muscle group at each subaxial level and less FI at C4-6 were significantly associated with less progression of C2-7 SVA over time. Moreover, there was a significant correlation between greater FI of the posteromedial muscle group measured at the C7 level and less NDI improvement at 4-6 months after ACDF., Conclusions: The findings highlight the importance of preoperative assessment of the cervical paraspinal muscle morphology as a predictor for patient-reported outcomes and maintenance of C2-7 SVA after ACDF.

Purpose: We aim to investigate the associations between lumbar paraspinal muscles and sagittal malalignment in patients undergoing lumbar three-column osteotomy., Methods: Patients undergoing three-column osteotomy between 2016 and 2021 with preoperative lumbar magnetic resonance imaging (MRI) and whole spine radiographs in the standing position were included. Muscle measurements were obtained using a validated custom software for segmentation and muscle evaluation to calculate the functional cross-sectional area (fCSA) and percent fat infiltration (FI) of the m. psoas major (PM) as well as the m. erector spinae (ES) and m. multifidus (MM). Spinopelvic measurements included pelvic incidence (PI), sacral slope (SS), pelvic tilt (PT), L1-S1 lordosis (LL), T4-12 thoracic kyphosis (TK), spino-sacral angle (SSA), C7-S1 sagittal vertical axis (SVA), T1 pelvic angle (TPA) and PI-LL mismatch (PI - LL). Statistics were performed using multivariable linear regressions adjusted for age, sex, and body mass index (BMI)., Results: A total of 77 patients (n = 40 female, median age 64 years, median BMI 27.9 kg/m 2 ) were analyzed. After adjusting for age, sex and BMI, regression analyses demonstrated that a greater fCSA of the ES was significantly associated with greater SS and SSA. Moreover, our results showed a significant correlation between a greater FI of the ES and a greater kyphosis of TK., Conclusion: This study included a large patient cohort with sagittal alignment undergoing three-column osteotomy and is the first to demonstrate significant associations between the lumbar paraspinal muscle parameters and global sagittal alignment. Our findings emphasize the importance of the lumbar paraspinal muscles in sagittal malalignment., (© 2024. The Author(s), under exclusive licence to Scoliosis Research Society.)

Study Design: Retrospective review of prospectively collected data., Objective: The authors aim to investigate the association between muscle functional group characteristics and sagittal alignment parameters in patients undergoing anterior cervical discectomy and fusion., Summary of Background Data: The relationship between the morphology of cervical paraspinal muscles and sagittal alignment is not well understood., Materials and Methods: Patients with preoperative cervical magnetic resonance imaging and cervical spine lateral radiographs in standing position who underwent anterior cervical discectomy and fusion between 2015 and 2018 were reviewed. Radiographic alignment parameters included C2 to 7 lordosis, C2 to 7 sagittal vertical axis (SVA), C2 slope, neck tilt, T1 slope, and thoracic inlet angle. Muscles from C3 to C7 were categorized into four functional groups: sternocleidomastoid group, anterior group, posteromedial group, and posterolateral group (PL). A custom-written Matlab software was used to assess the functional cross-sectional area (fCSA) and percent fat infiltration (FI) for all groups. Multivariable linear regression analyses were conducted and adjusted for age, sex, and body mass index., Results: A total of 172 patients were included. Regression analyses demonstrated that a greater C2 to 7 SVA was significantly associated with a greater FI of the anterior group from C3 to C5 and with a higher fCSA of the PL group at C3 to C4, and C6 to 7. A larger C2 slope was significantly correlated with a greater FI of the anterior group at C3 to C4 and a higher fCSA of the PL group from C3 to C5., Conclusion: This work proposes new insights into the complex interaction between sagittal alignment and cervical paraspinal muscles by emphasizing the importance of these muscles in sagittal alignment. The authors hypothesize that with cervical degeneration, the stabilizing function of the anterior muscles decreases, which may result in an increase in the compensatory mechanism of the PL muscles. Consequently, there may be a corresponding increase in the C2 to C7 SVA and a larger C2 slope., Competing Interests: S.A.A. reports royalties from Ortho Development, Corp.; private investments for Vestia Ventures MiRUS Investment, LLC, IVY II, LLC, ISPH II, LLC, ISPH 3, LLC, HS2, LLC, HSS ASC Development Network, LLC, and Centinel Spine (Vbros Venture Partners V); consulting fee from Depuy Synthes Products Inc., Clariance Inc., Kuros Biosciences AG, Ortho Development Corp., Medical Device Business Service Inc.; speaking and teaching arrangements of DePuy Synthes Products Inc.; membership of scientific advisory board of Depuy Synthes Products Inc., Clariance Inc., and Kuros Biosciences AG; Medical Device Business Service Inc. and trips/travel of Medical Device Business; research support from Spinal Kinetics Inc., outside the submitted work. C.F.P. reports royalties from NuVasive Inc. Accelus; ownership interest for 4WEB Medical/4WEB Inc.; Healthpoint Capital Partners, LP; ISPH II LLC; ISPH 3 Holdings LLC; Ivy Healthcare Capital Partners LLC; Medical Device Partners II LLC; Medical Device Partners III LLC; Orthobond Corporation; Spine Biopharma LLC; Tissue Differentiation Intelligence LLC; VBVP VI LLC; VBVP X LLC; Woven Orthopedics Technologies; consulting fees from 4WEB Medical/4WEB Inc., DePuy Synthes, NuVasive Inc., Spine Biopharma LLC, and Synexis LLC, Accelus; membership of scientific advisory board/other office of Healthpoint Capital Partners, Medical Device Partners II LLC, Orthobond Corporation, Spine Biopharma LLC, and Woven Orthopedic Technologies; and research support from 4WEB Medical/4WEB Inc., Mallinckrodt Pharmaceuticals, Camber Spine, and Centinel Spine, outside the submitted work. G.F.P. reports royalties from Lanx Inc., and Ortho Development Corp.; private investments for BCIMD; and stock ownership of Healthpoint Capital Partners, LP, outside the submitted work. H.A.P. reports research support from Kuros Biosciences AG and Expanding Innovations Inc.; and fellowship support from NuVasive Inc. and Kuros Biosciences BV, outside the submitted work. The remaining authors report no conflicts of interest., (Copyright © 2023 Wolters Kluwer Health, Inc. All rights reserved.)

Objective: Abdominal aortic calcification (AAC), often found incidentally on lateral lumbar radiographs, is increasingly recognized for its association with adverse outcomes in spine surgery. As a marker of advanced atherosclerosis affecting cardiovascular dynamics, this study evaluates AAC's impact on perioperative blood loss in posterior spinal fusion (PSF)., Methods: Patients undergoing PSF from March 2016 to July 2023 were included. Estimated blood loss (EBL) and total blood volume (TBV) were calculated. AAC was assessed on lateral lumbar radiographs according to the Kauppila classification. Predictors of the EBL-to-TBV ratio (%EBL/TBV) were examined via univariable and multivariable regression analyses, which adjusted for parameters such as hypertension and aspirin use., Results: A total of 199 patients (47.2% female) were analyzed. AAC was present in 106 patients (53.3%). AAC independently predicted %EBL/TBV, accounting for an increase in blood loss of 4.46% of TBV (95% CI 1.17-7.74, p = 0.008)., Conclusions: This is the first study to identify AAC as an independent predictor of perioperative blood loss in PSF. In addition to its link to degenerative spinal conditions and adverse postoperative outcomes, the relationship between AAC and increased blood loss warrants attention in patients undergoing PSF., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Study Design: Retrospective study., Objective: The aim of this study was to evaluate the association between severity and level of cervical central stenosis (CCS) and the fat infiltration (FI) of the cervical multifidus/rotatores (MR) at each subaxial levels., Summary of Background Data: The relationship between cervical musculature morphology and the severity of CCS is poorly understood., Methods: Patients with preoperative cervical magnetic resonance imaging (MRI) who underwent anterior cervical discectomy and fusion (ACDF) were reviewed. The cervical MR were segmented from C3 to C7 and the percent FI was measured using a custom-written Matlab software. The severity of the CCS at each subaxial level was assessed using a previously published classification. Grade 3, representing a loss of cerebrospinal fluid space and deformation of the spinal cord > 25%, was set as the reference and compared to the other gradings. Multivariable linear regression analyses were conducted and adjusted for age, sex, and body mass index., Results: 156 consecutive patients were recruited. A spinal cord compression at a certain level was significantly associated with a greater FI of the MR below that level. After adjustment for the above-mentioned confounders, our results showed that spinal cord compression at C3/4 and C4/5 was significantly associated with greater FI of the MR from C3 to C6 and C5 to C7, respectively. A spinal cord compression at C5/6 or C6/7 was significantly associated with greater FI of the MR at C7., Conclusion: Our results demonstrated significant correlations between the severity of CCS and a greater FI of the MR. Moreover, significant level-specific correlations were found. A significant increase in FI of the MR at the levels below the stenosis was observed in patients presenting with spinal cord compression. Given the segmental innervation of the MR, the increased FI might be attributed to neurogenic atrophy., Level of Evidence: 3., Competing Interests: The authors report no conflicts of interest., (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)

Background Context: Machine learning is a powerful tool that has become increasingly important in the orthopedic field. Recently, several studies have reported that predictive models could provide new insights into patient risk factors and outcomes. Anterior cervical discectomy and fusion (ACDF) is a common operation that is performed as an outpatient procedure. However, some patients are required to convert to inpatient status and prolonged hospitalization due to their condition. Appropriate patient selection and identification of risk factors for conversion could provide benefits to patients and the use of medical resources., Purpose: This study aimed to develop a machine-learning algorithm to identify risk factors associated with unplanned conversion from outpatient to inpatient status for ACDF patients., Study Design/setting: This is a machine-learning-based analysis using retrospectively collected data., Patient Sample: Patients who underwent one- or two-level ACDF in an ambulatory setting at a single specialized orthopedic hospital between February 2016 to December 2021., Outcome Measures: Length of stay, conversion rates from ambulatory setting to inpatient., Methods: Patients were divided into two groups based on length of stay: (1) Ambulatory (discharge within 24 hours) or Extended Stay (greater than 24 hours but fewer than 48 hours), and (2) Inpatient (greater than 48 hours). Factors included in the model were based on literature review and clinical expertise. Patient demographics, comorbidities, and intraoperative factors, such as surgery duration and time, were included. We compared the performance of different machine learning algorithms: Logistic Regression, Random Forest (RF), Support Vector Machine (SVM), and Extreme Gradient Boosting (XGBoost). We split the patient data into a training and validation dataset using a 70/30 split. The different models were trained in the training dataset using cross-validation. The performance was then tested in the unseen validation set. This step is important to detect overfitting. The performance was evaluated using the area under the curve (AUC) of the receiver operating characteristics analysis (ROC) as the primary outcome. An AUC of 0.7 was considered fair, 0.8 good, and 0.9 excellent, according to established cut-offs., Results: A total of 581 patients (59% female) were available for analysis. Of those, 140 (24.1%) were converted to inpatient status. The median age was 51 (IQR 44-59), and the median BMI was 28 kg/m 2 (IQR 24-32). The XGBoost model showed the best performance with an AUC of 0.79. The most important features were the length of the operation, followed by sex (based on biological attributes), age, and operation start time. The logistic regression model and the SVM showed worse results, with an AUC of 0.71 each., Conclusions: This study demonstrated a novel approach to predicting conversion to inpatient status in eligible patients for ambulatory surgery. The XGBoost model showed good predictive capabilities, superior to the older machine learning approaches. This model also revealed the importance of surgical duration time, BMI, and age as risk factors for patient conversion. A developing field of study is using machine learning in clinical decision-making. Our findings contribute to this field by demonstrating the feasibility and accuracy of such methods in predicting outcomes and identifying risk factors, although external and multi-center validation studies are needed., Competing Interests: Declaration of Competing Interest One or more of the authors declare financial or professional relationships on ICMJE-TSJ disclosure forms., (Copyright © 2023 Elsevier Inc. All rights reserved.)

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 (β = 2.1, P <0.001) and Pfirrmann grade (β = 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., Competing Interests: A.A.S. reports royalties from Ortho Development, Corp.; private investments for Vestia Ventures MiRUS Investment, LLC, IVY II, LLC, ISPH II, LLC, ISPH 3, LLC, HS2, LLC, HSS ASC Development Network, LLC, and Centinel Spine (Vbros Venture Partners V); consulting fee from Depuy Synthes Products Inc., Clariance Inc., Kuros Biosciences AG, Ortho Development Corp., Medical Device Business Service Inc.; speaking and teaching arrangements of DePuy Synthes Products Inc.; membership of scientific advisory board of Depuy Synthes Products Inc., Clariance Inc., and Kuros Biosciences AG; Medical Device Business Service Inc. and trips/travel of Medical Device Business; research support from Spinal Kinetics Inc., outside the submitted work. Dr. F.P.C. reports royalties from NuVasive Inc. Accelus; ownership interest for 4WEB Medical/4WEB Inc.; Healthpoint Capital Partners, LP; ISPH II, LLC; ISPH 3 Holdings, LLC; Ivy Healthcare Capital Partners, LLC; Medical Device Partners II, LLC; Medical Device Partners III, LLC; Orthobond Corporation; Spine Biopharma, LLC; Tissue Differentiation Intelligence, LLC; VBVP VI, LLC; VBVP X, LLC; Woven Orthopedics Technologies; consulting fees from 4WEB Medical/4WEB Inc., DePuy Synthes, NuVasive Inc., Spine Biopharma, LLC, and Synexis, LLC, Accelus; membership of scientific advisory board/other office of Healthpoint Capital Partners, Medical Device Partners II, LLC, Orthobond Corporation, Spine Biopharma, LLC, and Woven Orthopedic Technologies; and research support from 4WEB Medical/4WEB, Inc., Mallinckrodt Pharmaceuticals, Camber Spine, and Centinel Spine, outside the submitted work. F.P.G. reports royalties from Lanx Inc., and Ortho Development Corp.; private investments for BCIMD; and stock ownership of Healthpoint Capital Partners, LP, outside the submitted work. Hughes reports research support from Kuros Biosciences AG and fellowship support from NuVasive Inc. and Kuros Biosciences BV, outside the submitted work. The remaining authors report no conflicts of interest., (Copyright © 2023 Wolters Kluwer Health, Inc. All rights reserved.)

Purpose: Intervertebral vacuum phenomenon (IVP) and paraspinal muscular atrophy are age-related changes in the lumbar spine. The relationship between both parameters has not been investigated. We aimed to analyze the correlation between IVP and paraspinal muscular atrophy in addition to describing the lumbar vacuum severity (LVS) scale, a new parameter to estimate lumbar degeneration., Methods: We analyzed patients undergoing spine surgery between 2014 and 2016. IVP severity was assessed utilizing CT scans. The combination of vacuum severity on each lumbar level was used to define the LVS scale, which was classified into mild, moderate and severe. MRIs were used to evaluate paraspinal muscular fatty infiltration of the multifidus and erector spinae. The association of fatty infiltration with the severity of IVP at each lumbar level was assessed with a univariable and multivariable ordinal regression model., Results: Two hundred and sixty-seven patients were included in our study (128 females and 139 males) with a mean age of 62.6 years (55.1-71.2). Multivariate analysis adjusted for age, BMI and sex showed positive correlations between LVS-scale severity and fatty infiltration in the multifidus and erector spinae, whereas no correlation was observed in the psoas muscle., Conclusion: IVP severity is positively correlated with paraspinal muscular fatty infiltration. This correlation was stronger for the multifidus than the erector spinae. No correlations were observed in the psoas muscle. The lumbar vacuum severity scale was significantly correlated with advanced disc degeneration with vacuum phenomenon., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Background: The recommended timing for returning to common activities after cervical spine surgery varies widely among physicians based on training background and personal opinion, without clear guidelines or consensus. The purpose of this study was to analyze spine surgeons' responses about the recommended timing for returning to common activities after different cervical spine procedures., Methods: This was a survey study including 91 spine surgeons. The participants were asked to complete an anonymous online survey. Questions regarding their recommended time for returning to regular activities (showering, driving, biking, running, swimming, sedentary work, and nonsedentary work) after anterior cervical decompression and fusion (ACDF), cervical disc replacement (CDR), posterior cervical decompression and fusion (PCDF), and laminoplasty were included. Comparisons of recommended times for return to activities after each surgical procedure were made based on surgeons' years in practice., Results: For ACDF and PCDF, there were no statistically significant differences in recommended times for return to any activity when stratified by years in practice. When considering CDR, return to non-sedentary work differed between surgeons in practice for 10 to 15 years, who recommended return at 3 months, and all other groups of surgeons, who recommended 6 weeks. Laminoplasty surgery yielded the most variability in activity recommendations, with earlier recommended return (6 weeks) to biking, non-sedentary work, and sedentary work in the most experienced surgeon group (>15 years in practice) than in all other surgeon experience groups (3 months)., Conclusions: We observed significant variability in surgeon recommendations for return to regular activities after cervical spine surgery., Competing Interests: All of the authors note no relationships or conflicts pertaining to the submitted manuscript. One or more authors declare financial interests or personal relationships outside of the submitted work as specified on required ICMJE-NASSJ Disclosure Forms and outlined here. Dr. Cammisa does disclose relevant financial activities outside the submitted work: Royalties, Stock Ownership, Private Investments, Consulting, Board of Directors, Scientific Advisory Board, Research Support (4Web Medical, Camber Spine, Centinel Spine). Dr. Girardi does disclose relevant financial activities outside the submitted work: Royalties, Stock Ownership, Private Investments. Dr. Hughes does disclose relevant financial activities outside the submitted work: Stock Ownership, Research Support (Nuvasive Inc., Kuros Biosciences, Kuros Biosurgery, Expanding Innovations). Dr. Sama does disclose relevant financial activities outside the submitted work: Royalties, Private investments, Consulting, Speaking and/or Teaching Arrangements, Scientific Advisory Board, Research Support (Spinal Kinetics)., (© 2024 The Author(s).)

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., Competing Interests: The authors report no conflicts of interest., (Copyright © 2023 Wolters Kluwer Health, Inc. All rights reserved.)

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., Competing Interests: A.A.S. reports royalties from Ortho Development, Corp.; private investments for Vestia Ventures MiRUS Investment, LLC, IVY II, LLC, ISPH II, LLC, ISPH 3, LLC, HSS ASC Development Network, LLC, and Centinel Spine (Vbros Venture Partners V); consulting fee from Depuy Synthes Products, Inc., Clariance, Inc., Kuros Biosciences AG, Ortho Development Corp., Medical Device Business Service, Inc.; speaking and teaching arrangements of DePuy Synthes Products, Inc.; membership of scientific advisory board of Depuy Synthes Products, Inc., Clariance, Inc., and Kuros Biosciences AG; Medical Device Business Service, Inc. and trips/travel of Medical Device Business; research support from Spinal Kinetics, Inc., outside the submitted work. F.P.C. reports royalties from NuVasive, Inc. Accelus; ownership interest for 4WEB Medical/4WEB, Inc.; Healthpoint Capital Partners, LP; ISPH II, LLC; ISPH 3 Holdings, LLC; Ivy Healthcare Capital Partners, LLC; Medical Device Partners II, LLC; Medical Device Partners III, LLC; Orthobond Corporation; Spine Biopharma, LLC; Tissue Differentiation Intelligence, LLC; VBVP VI, LLC; VBVP X, LLC; Woven Orthopedics Technologies; consulting fees from 4WEB Medical/4WEB, Inc., DePuy Synthes, NuVasive, Inc., Spine Biopharma, LLC, and Synexis, LLC, Accelus; membership of scientific advisory board/other office of Healthpoint Capital Partners, Medical Device Partners II, LLC, Orthobond Corporation, Spine Biopharma, LLC, and Woven Orthopedic Technologies; and research support from 4WEB Medical/4WEB, Inc., Mallinckrodt Pharmaceuticals, Camber Spine, and Centinel Spine, outside the submitted work. F.P.G. reports royalties from Lanx, Inc., and Ortho Development Corp.; private investments for BCIMD; and stock ownership of Healthpoint Capital Partners, LP, outside the submitted work. A.P.H. reports research support from Kuros Biosciences AG; and fellowship support from NuVasive, Inc. and Kuros Biosciences BV, outside the submitted work. G.S. receives consulting fees from Stryker and Camber spine. The remaining authors declare no conflict of interest., (Copyright © 2023 Wolters Kluwer Health, Inc. All rights reserved.)

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., (Copyright © 2023 International Association for the Study of Pain.)

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., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Background Context: Although the effect of lumbar spinal stenosis (LSS) on the lower extremities is well documented, limited research exists on the effect of spinal stenosis on the posterior paraspinal musculature (PPM). Similar to neurogenic claudication, moderate to severe spinal canal compression can also interfere with the innervation of the PPM, which may result in atrophy and increased fatty infiltration (FI)., Purpose: This study aims to assess the association between LSS and atrophy of the PPM., Study Design: Retrospective cross-sectional study., Patient Sample: Patients undergoing MRI scans at a tertiary orthopedic center for low back pain or as part of a preoperative evaluation., Outcome Measures: The functional cross-sectional area (fCSA) and percent fatty infiltration (FI) of the PPM at L4., Methods: Lumbar MRIs of patients at a tertiary orthopedic center indicated due to lower back pain (LBP) or as a presurgical workup were analyzed. Patients with previous spinal fusion surgery or scoliosis were excluded. LSS was assessed according to the Schizas classification at all lumbar levels. The cross-sectional area of the PPM was measured on a T2-weighted MRI sequence at the upper endplate of L4. The fCSA and fatty infiltration (FI) were calculated using custom software. Crude differences in FI and fCSA between patients with no stenosis and at least mild stenosis were tested with the Wilcoxon signed-rank test. To account for possible confounders, a multivariable linear regression model was used to adjust for age, sex, body mass index (BMI), and disc degeneration. A subgroup analysis according to MRI indication was performed., Results: A total of 522 (55.7% female) patients were included. The median age was 61 years (IQR: 51-71). The greatest degree of moderate and severe stenosis was found at L4/5, 15.7%, and 9.2%, respectively. Stenosis was the least severe at L5/S1 and was found to be 2% for moderate and 0.2% for severe stenosis. The Wilcoxon test showed significantly increased FI of the PPM with stenosis at any lumbar level (p<.001), although no significant decrease in fCSA was observed. The multivariable regression model showed a significant increase in FI with increased LSS at L1/2, L2/3, and L3/4 (p=.013, p<.01 and p=.003). The severity of LSS at L4/5 showed a positive association with the fCSA (p=.019). The subgroup analysis showed, the effect of LSS was more pronounced in nonsurgical patients than in patients undergoing surgery., Conclusions: In this study, we demonstrated a significant and independent association between LSS and the composition of the PPM, which was dependent on the level of LSS relative to the PPM. In addition to neurogenic claudication, patients with LSS might be especially susceptible to axial muscle wasting, which could worsen LSS due to increased spinal instability, leading to a positive feedback loop., Competing Interests: Declaration of Competing Interest One or more of the authors declare financial or professional relationships on ICMJE-TSJ disclosure forms., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Objective: The cervical multifidus and rotatores muscles are innervated by the posterior rami of the spinal nerves of the corresponding level, and it has been hypothesized that cervical foraminal stenosis (CFS) affecting the spinal nerves results in changes in these muscles. The purpose of this study was to evaluate the relationship between the severity of CFS and fat infiltration (FI) of the multifidus and rotatores muscles., Methods: Patients who received preoperative cervical MRI, underwent anterior cervical decompression and fusion between 2015 and 2018, and met inclusion and exclusion criteria were included. Multifidus and rotatores muscles were segmented bilaterally from C3 to C7, and the percent FI was measured using custom-written MATLAB software. The severity of the CFS was assessed by the Kim classification. Multivariable linear mixed models were conducted and adjusted for age, sex, BMI, and repeated measures., Results: In total, 149 patients were included. Linear mixed modeling results showed that a more severe CFS at C3-4 was correlated with a greater FI of the multifidus and rotatores muscles at C4 (estimate 0.034, 95% CI 0.003-0.064; p = 0.031), a more severe CFS at C4-5 was correlated with a greater FI of the multifidus and rotatores muscles at C5 (estimate 0.037, 95% CI 0.015-0.057; p < 0.001), a more severe CFS at C5-6 was correlated with a greater FI of the multifidus and rotatores muscles at C6 (estimate 0.041, 95% CI 0.019-0.062; p < 0.001) and C7 (estimate 0.035, 95% CI 0.012-0.058; p = 0.003), and a more severe CFS at C6-7 was correlated with a greater FI of the multifidus and rotatores muscles at C7 (estimate 0.049, 95% CI 0.027-0.071; p < 0.001)., Conclusions: These results demonstrated level- and side-specific correlations between the FI of the multifidus and rotatores muscles and severity of CFS. Given the segmental innervation of the multifidus and rotatores muscles, the authors hypothesize that the observed increased FI could be reflective of changes due to muscle denervation from CFS.

Study Design: Retrospective analysis of longitudinal data., Objective: To assess the association between the paraspinal musculature (PM) and lumbar endplate degeneration., Background: The PM is essential for spinal stability, while the vertebral endplate is pivotal for nutrient transport and force distribution. The clinical importance of both has been highlighted in recent literature, though little is known about their interaction., Methods: We identified patients with lumbar MRI scans due to low back pain, with a 3-year interval between MRI scans. Endplate damage was assessed by the total endplate score (TEPS) at each lumbar level. The PM was evaluated for its functional cross-sectional area and fatty infiltration (FI) at the L4 level. We used a generalized mixed model to analyze the association between PM parameters and TEPS at timepoint one, adjusting for age, sex, BMI, diabetes, hypertension, and smoking status. The association with the progression of endplate damage was analyzed through an ordinal regression model, additionally adjusted for TEPS at baseline., Results: In all, 329 patients were included, with a median follow-up time of 3.4 years. Participants had a median age of 59 and a BMI of 25.8 kg/m 2 . In the univariate analysis, FI of the posterior PM was significantly associated with TEPS at baseline (β: 0.08, P <0.001) and progression of TEPS [Odds Ratio (OR): 1.03, P =0.020] after adjustment for confounders. The β and OR in this analysis are per percent of FI. In a binary analysis, patients with FI≥40% had an OR of 1.92 ( P =0.006) for the progression of TEPS., Conclusions: This is the first longitudinal study assessing the relationship between PM and endplate degeneration, demonstrating the association between PM atrophy and the progression of endplate degeneration. This insight may aid in identifying patients at risk for degenerative lumbar conditions and guide research into preventive measures., Competing Interests: A.A.S. reports royalties from Ortho Development, Corp.; private investments for Vestia Ventures MiRUS Investment, LLC, IVY II, LLC, ISPH II, LLC, ISPH 3, LLC, HS2, LLC, HSS ASC Development Network, LLC, and Centinel Spine (Vbros Venture Partners V); consulting fee from Depuy Synthes Products, Inc., Clariance, Inc., Kuros Biosciences AG, Ortho Development Corp., Medical Device Business Service, Inc.; speaking and teaching arrangements of DePuy Synthes Products, Inc.; membership of the scientific advisory board of Depuy Synthes Products, Inc., Clariance, Inc., and Kuros Biosciences AG; Medical Device Business Service, Inc. and trips/travel of Medical Device Business; research support from Spinal Kinetics, Inc., outside the submitted work. F.P.C. reports royalties from NuVasive, Inc. Accelus; ownership interest for 4WEB Medical/4WEB, Inc.; Healthpoint Capital Partners, LP; ISPH II, LLC; ISPH 3 Holdings, LLC; Ivy Healthcare Capital Partners, LLC; Medical Device Partners II, LLC; Medical Device Partners III, LLC; Orthobond Corporation; Spine Biopharma, LLC; Tissue Differentiation Intelligence, LLC; VBVP VI, LLC; VBVP X, LLC; Woven Orthopedics Technologies; consulting fees from 4WEB Medical/4WEB, Inc., DePuy Synthes, NuVasive, Inc., Spine Biopharma, LLC, and Synexis, LLC, Accelus; membership of scientific advisory board/other office of Healthpoint Capital Partners, Medical Device Partners II, LLC, Orthobond Corporation, Spine Biopharma, LLC, and Woven Orthopedic Technologies; and research support from 4WEB Medical/4WEB, Inc., Mallinckrodt Pharmaceuticals, Camber Spine, and Centinel Spine, outside the submitted work. F.P.G. reports royalties from Lanx, Inc., and Ortho Development Corp.; private investments for BCIMD; and stock ownership of Healthpoint Capital Partners, LP, outside the submitted work. A.P.H. reports research support from Kuros Biosciences AG; and fellowship support from NuVasive, Inc. and Kuros Biosciences BV, outside the submitted work. The remaining authors declare no conflicts of interest., (Copyright © 2023 Wolters Kluwer Health, Inc. All rights reserved.)

Introduction: The aim of this examination was to assess, which risk factors impair bone healing after triple pelvic osteotomy (TPO) in the treatment of symptomatic hip dysplasia., Methods: A consecutive series of 241 TPO was reviewed retrospectively. Of these, a set of five postoperative radiographs was available, performed in a standardized regimen in the first year after surgery. Two experienced observers had to agree on the existence of a non-union on the radiographs obtained 1 year after TPO. Both observers measured the lateral center edge angle (LCEA) and acetabular index (AI) on all radiographs. Besides patient-specific risk factors, the magnitudes of acetabular correction and the amounts of a detectable slight change in acetabular correction were assessed. Binary logistic regression analysis and chi-squared test were used to detect the impact of the risk factor on bone healing., Results: A total of 222 cases were left for further examination. In 19 of these, at least one osteotomy was not healed completely one year after surgery. Binary logistic regression showed a significant relationship between the risk factors "age" (p < 0.001; odds ratio (OR) 1.109 (95% CI 1.05-1.18)) as well as "magnitude of acetabular correction (LCEA)" (p = 0.01; OR 1.087 (95% CI 1.02-1.16)) and non-union. Pearson's chi-square test showed a relationship between the risk factor "wound healing disorder" and non-union (p < 0.001). LCEA and AI showed a slight increase from the first to the last follow-up (observer 1: 1.6° and 1.3°, resp.), but regression analysis for the risk factor "amount of postoperative change of acetabular correction (LCEA, AI)" did not show statistically significant values., Conclusion: The age at surgery and the magnitude of acetabular correction negatively influenced the healing progress of the osteotomy sites. The amount of a slight postoperative change of LCEA and AI did not correlate with a non-union., (© 2023. The Author(s).)

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., Competing Interests: A.A.S. reports royalties from Ortho Development Corp.; private investments for Vestia Ventures MiRUS Investment LLC, IVY II LLC, ISPH II LLC, ISPH 3 LLC, HSS ASC Development Network LLC, and Centinel Spine (Vbros Venture Partners V); consulting fee from Depuy Synthes Products Inc., Clariance Inc., Kuros Biosciences AG, Ortho Development Corp., Medical Device Business Service Inc.; speaking and teaching arrangements of DePuy Synthes Products Inc.; membership of scientific advisory board of Depuy Synthes Products Inc., Clariance Inc., and Kuros Biosciences AG; Medical Device Business Service Inc.; and trips/travel of Medical Device Business; research support from Spinal Kinetics Inc., outside the submitted work. F.P.C. reports royalties from NuVasive Inc., Accelus; ownership interest for 4WEB Medical/4WEB Inc.; Healthpoint Capital Partners, LP; ISPH II LLC; ISPH 3 Holdings LLC; Ivy Healthcare Capital Partners LLC; Medical Device Partners II LLC; Medical Device Partners III LLC; Orthobond Corporation; Spine Biopharma LLC; Tissue Differentiation Intelligence LLC; VBVP VI LLC; VBVP X LLC; Woven Orthopedics Technologies; consulting fees from 4WEB Medical/4WEB Inc., DePuy Synthes, NuVasive Inc., Spine Biopharma LLC, and Synexis LLC, Accelus; membership of scientific advisory board/other office of Healthpoint Capital Partners, Medical Device Partners II LLC, Orthobond Corporation, Spine Biopharma LLC, and Woven Orthopedic Technologies; and research support from 4WEB Medical/4WEB Inc., Mallinckrodt Pharmaceuticals, Camber Spine, and Centinel Spine, outside the submitted work. F.P.G. reports royalties from Lanx Inc., and Ortho Development Corp.; private investments for BCIMD; and stock ownership of Healthpoint Capital Partners LP, outside the submitted work. A.P.H. reports research support from Kuros Biosciences AG; and fellowship support from NuVasive Inc. and Kuros Biosciences BV, outside the submitted work. The remaining authors report no conflicts of interest., (Copyright © 2023 Wolters Kluwer Health, Inc. All rights reserved.)

Purpose: Only a few publications considered the influence of the spinopelvic parameters on below-hip anatomy. There is a lack of evidence about the relationship between the anatomic spinopelvic parameters and the posterior tibial slope (PTS). Therefore, the aim of this study was to analyze the association between fixed anatomic spinopelvic parameters and PTS., Methods: Adult patients presenting with lumbar, thoracic, or cervical complaints together with knee pain at a single hospital between 2017 to 2022 with available standing full-spine lateral radiograph and lateral knee radiograph were retrospectively reviewed. The measured parameters included the pelvic incidence (PI), the sacral kyphosis (SK), the pelvisacral angle, the sacral anatomic orientation (SAO), the sacral table angle, the sacropelvic angle and the PTS. Pearson's correlations and linear regression analyses were conducted., Results: A total of 80 patients (44 women), median age 63 years were analyzed. A strong positive correlation was identified between PI and PTS (r = 0.70, p < 0.001). A strong negative correlation was observed between PI and SAO (r = - 0.74, p < 0.001). A strong positive correlation was observed between PI and SK (r = 0.81, p < 0.001). A univariable linear regression analysis showed that PTS can be deduced from PI according to the following formula: PTS = 0.174 × PI - 1.138., Conclusion: This study is the first to support a positive correlation between the PI and the PTS. We demonstrate that knee anatomy is individually correlated to pelvic shape and therefore influences spinal posture., (© 2023. The Author(s).)

Background: Abdominal aortic calcification (AAC) is associated with lower back pain, reduced bone mineral density of the spine. Vascular changes could also affect the already sparsely perfused intervertebral endplate and intervertebral disc., Methods: Lumbar MRIs and lateral radiographs of patients with lower back pain were retrospectively analyzed. AAC was assessed on lateral lumbar radiographs according to the Kauppila score, with a maximum score of 24. Patients were grouped into no (AAC = 0), moderate (AAC 1 to ≤ 4), and severe AAC (AAC ≥ 5). Endplate and disc degeneration were classified according to the total endplate score (TEPS) and Pfirrmann classification. The associations between AAC and degenerative changes was analyzed with a generalized mixed model and was adjusted for age, sex, body mass index as well as diabetes mellitus, and smoking status., Results: A total of 217 patients (47.9% female) were included in the analysis, totaling 1085 intervertebral levels. Of those, 45 (20.7%) patients had moderate, and 39 (18%) had severe AAC. The results of the generalized mixed model showed no significant association between AAC and disc degeneration (p > 0.05). In contrast, a significant positive association between AAC and the severity of TEPS (β: 0.51, 95% CI: 1.92-2.12, p = 0.004) was observed in the multivariable analysis., Conclusions: This study demonstrates an independent association between AAC and endplate degeneration. These findings expand our knowledge about the degenerative cascade of the lumbar spine and suggest that AAC might be a modifiable risk factor for endplate changes., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Background: Aortic abdominal calcification (AAC) is associated with spine-related conditions, such as lower back pain and reduced bone mineral density. Similar to peripheral vascular disease, AAC possibly reduces blood flow to the lumbar posterior paraspinal muscles (PPM) which may lead to atrophy and increased fatty infiltration., Methods: Imaging of patients with lower back pain was analyzed. AAC was assessed on lateral lumbar radiographs according to the Kauppila classification. The cross-sectional area of the PPM was measured on a T2-weighted axial MRI sequence and the functional cross-sectional area (fCSA) and fatty infiltration (FI) were calculated with custom software. The association of AAC and FI as well as AAC and fCSA was assessed by multivariable linear regression, adjusted for age, sex, body mass index (BMI), diabetes, and smoking., Results: Two hundred and thirty patients (47.8% female) with a median age of 60 years (IQR 48-68) were analyzed. In patients, without AAC the median FI of the PPM was 33.3% (IQR 29.1-37.6%), compared to 44.6% (IQR 38.5-54.3%) in patients with AAC (p < 0.001). In the multivariable linear regression, both fCSA and FI of the PPM were significantly and independently associated with the degree of AAC (p = 0.037 and p = 0.015, respectively)., Conclusions: This is the first study to demonstrate a significant and independent association between AAC and PPM morphology. The results of this study improve our understanding of the interaction between AAC and spinal musculature, with AAC being a reason for atrophy of the PPM., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Spondylodiscitis is a severe infectious disease of the spine that affects the intervertebral discs and adjacent vertebrae. It can lead to nonspecific pain, limited mobility, and destruction of spinal structures. Various pathogens, such as bacteria, fungi, or parasites, can trigger the disease. An early diagnosis and targeted treatment are crucial to reduce the risk of serious complications. Magnetic resonance imaging (MRI) with contrast agent and blood tests are essential for the diagnosis and assessing the course of the disease. The treatment includes conservative and surgical approaches. Conservative treatment consists of a minimum 6‑week antibiotic course and immobilization of the affected area. Surgical interventions, along with several weeks of antibiotic therapy, are indicated for instabilities or complications in order to eliminate the infection focus and to restore spinal stability., (© 2023. The Author(s), under exclusive licence to Springer Medizin Verlag GmbH, ein Teil von Springer Nature.)

Scoliosis and Scheuermann's disease are common spinal deformities that affect a substantial population, particularly adolescents, often impacting their quality of life. This comprehensive review aims to present a detailed understanding of these conditions, their diagnosis, and various treatment strategies. Through an extensive exploration of current literature, the review discusses the etiology of these spinal deformities and the use of diagnostic tools such as X-rays and MRI. It further delves into the range of treatment options available, from conservative approaches such as physiotherapy and bracing to more invasive surgical interventions. The review underscores the necessity of an individualized treatment approach, taking into account factors such as the patient's age, the severity of the curvature, and overall health. This all-encompassing perspective on scoliosis and Scheuermann's disease will aid in evidence-based decision making in their management with the goal of improving patient outcomes.

Background: Retearing of the supraspinatus (SSP) tendon after repair is relatively common, but its cause is rarely clear. Although the role of acromion morphology and glenoid orientation in the pathogenesis of primary SSP tendon tears have frequently been analyzed, their association with the risk of rerupture of a repaired SSP tendon is poorly understood., Questions/purposes: (1) Is acromial morphology associated with the risk of retear after SSP tendon repair? (2) Is there an association between inclination and version of the glenoid and the odds for retear of the SSP tendon after repair? (3) Are there differences in outcome scores between patients who had intact cuff repairs and those who had retears?, Methods: Between August 2012 and December 2015, we treated 92 patients for SSP tendon tears; all of these patients were considered for inclusion in the present study. We considered patients with complete tear of the SSP that was reconstructed with a double-row repair and a minimum follow-up of 2 years as potentially eligible. Based on these criteria, 28% (26 of 92) were excluded because they had a partial rupture and did not receive a double-row reconstruction. A further 9% (eight of 92) were excluded because of missing planes or slices (such as sagittal, axial, or frontal) on MRI, and another 3% (three of 92) were lost before the minimum study follow-up interval or had incomplete datasets, leaving 60% (55 of 92) for inclusion in the present analysis. All included patients had a minimum follow-up of 2 years; follow-up with MRI occurred at a mean duration of 2.3 ± 0.4 years postoperatively. All patients were asked to complete the Western Ontario Rotator Cuff Index and Oxford Shoulder Scores, and they underwent MRI of the operated-on shoulder. Preoperative true AP radiographs and MR images of the affected shoulders were retrospectively assessed by measuring the acromiohumeral interval, critical shoulder angle, acromial slope, acromial tilt, acromial index, lateral acromial angle, and glenoid version and inclination. The patients also underwent acromioplasty, in which the underface of the acromion was flattened. To rule out any change in the above parameters because of acromioplasty, these parameters were compared using preoperative and postoperative MR images and showed no difference. In addition, the tendon integrity and quality on postoperative MRI were analyzed independently of one another by the same two observers using the Sugaya and Castricini classifications, accounting for atrophy and fatty degeneration of the SSP muscle. To assess interobserver reliability, the two observers took measurements independently from each other. They were orthopaedic residents who completed a training session before taking the measurements. All measurements had excellent intrarater (Cronbach alpha 0.996 [95% confidence interval (CI) 0.99 to 1.00; p > 0.01) and interrater (interrater correlation coefficient 0.975 [95% CI 0.97 to 0.98]; p > 0.01) reliabilities. To answer the study's first question, SSP integrity on postoperative MRI was compared with acromial morphologic parameters measured on preoperative AP radiographs and MR images. To answer the second question, the postoperative integrity and quality of the SSP tendon were correlated with glenoid inclination and glenoid version. To answer our third question, we compared outcome scores between patients with intact SSP tendons and those with reruptured SSP tendons. To investigate any correlation among the acromial morphology, glenoid orientation, and postoperative outcomes, a binomial logarithmic regression analysis was performed. Receiver operating characteristic curves were used to determine cutoff points for the radiologic parameters that showed a correlation in the binomial regression analysis., Results: After controlling for potentially confounding variables such as acromioplasty or preoperative fatty infiltration as well as muscle atrophy, the only morphological parameters associated with a higher risk (adjusted odds ratio) of SSP tendon rerupture were the acromiohumeral interval (adjusted OR 0.9 [95% CI 0.9 to 0.99]; p < 0.01) and acromial slope (adjusted OR 1.4 [95% CI 1.1 to 1.8]; p < 0.01). The critical shoulder angle, acromial tilt, acromial index, and lateral acromial angle were not associated with the risk of rerupture. The cutoff values for acromial slope and acromiohumeral interval were 24.5° and 7.4 mm, respectively. Patients with an acromiohumeral interval smaller than 7.4 mm or an acromial slope greater than 24.5° had higher odds (acromiohumeral interval: OR 11 [95% CI 2 to 46]; p = 0.01 and acromial slope: OR 9 [95% CI 2 to 46]; p = 0.04) for rerupture of the SSP. No difference was found between patients with intact SSP tendons and those with reruptured SSP tendons in terms of glenoid inclination (6° ± 4° versus 6° ± 3°, mean difference 0.8° [-1° to 3°]; p < 0.48) and glenoid version (-2° ± 3° versus -3° ± 3°, mean difference 1° [-1° to 3°]; p < 0.30). No difference was found between the intact and reruptured SSP groups regarding clinical outcomes (Western Ontario Rotator Cuff Index: 98 ± 2 versus 97 ± 3, mean difference 0.73 [95% CI -0.30 to 0.31]; p = 0.96; Oxford Shoulder Score: 26 ± 13 versus 23 ± 10, mean difference 2.80 [95% CI -4.12 to 9.72]; p = 0.41)., Conclusion: The preoperative acromiohumeral interval and acromial slope are associated with SSP tendon rerupture after repair. Conversely, the critical shoulder angle, acromial tilt, lateral acromial angle, and acromial index had no association with the postoperative outcome. Additionally, glenoid inclination and version were not associated with the rerupture rate after SSP tendon repair. A detailed analysis of the acromiohumeral interval and acromial slope is recommended in clinical practice in patients undergoing SSP tendon repair. Surgeons should consider measuring the acromiohumeral interval and acromial slope preoperatively when performing SSP repair, especially in the context of planned acromioplasties. Future studies should investigate the role of acromioplasty during SSP repair in patients with a pathologic acromial slope and acromiohumeral interval. In this context, it should be determined whether a more-radical acromioplasty could reduce the risk of rerupture of the SSP in these patients., Level of Evidence: Level III, therapeutic study., Competing Interests: Each author certifies that there are no funding or commercial associations (consultancies, stock ownership, equity interest, patent/licensing arrangements, etc.) that might pose a conflict of interest in connection with the submitted article related to the author or any immediate family members. All ICMJE Conflict of Interest Forms for authors and Clinical Orthopaedics and Related Research® editors and board members are on file with the publication and can be viewed on request., (Copyright © 2022 by the Association of Bone and Joint Surgeons.)

Background: Frailty status and hypoalbuminemia have been associated with higher rates of complications after spine surgery. However, the combination of both conditions has not been fully analyzed. The objective of this study was to assess the effect of frailty and hypoalbuminemia on the risk of complications after spine surgery., Methods: The American College of Surgeons National Surgical Quality Improvement Program (ACS-NSQIP) database from 2009 to 2019 was used. Frailty status was calculated using the modified 5-item frailty index (mFI-5). Patients were classified into nonfrail (mFI = 0), pre-frail (mFI = 1), and frail (mFI ≥2) groups and also based on albumin levels into normal (≥3.5 g/dL) and hypoalbuminemia groups (<3.5 g/dL). The latter group was also subclassified into mild and severe hypoalbuminemia groups. Multivariable analysis was used. A Spearman ρ correlation between albuminemia and mFI-5 was also performed., Results: A total of 69,519 patients (36,705 men [52.8%] and 32,814 women [47.2%]) with a mean age of 61.0 ± 13.2 years were included. Patients were classified as nonfrail (n = 24,897), pre-frail (n = 28,897), and frail groups (n = 15,725). Hypoalbuminemia was significantly higher in the frail group (11.4%) compared with the nonfrail group (4.3%). An inverse correlation was observed between albumin levels and frailty status (ρ = -0.139; P < 0.0001). Frail patients with severe hypoalbuminemia had significantly higher risk of complications (odds ratio [OR], 5.0), reoperation (OR, 3.3), readmission (OR, 3.1), and mortality (OR, 31.8) compared with patients without hypoalbuminemia., Conclusions: The combination of frailty and hypoalbuminemia significantly increases the risk of complications after spine surgery. The prevalence of hypoalbuminemia in the frailty group was significantly higher than in nonfrail patients (11.4% vs. 4.3%). Both conditions should be evaluated preoperatively., (Copyright © 2023 Elsevier Inc. All rights reserved.)

Objective: The aim of this meta-analysis was to investigate the impact of intravenous iloprost therapy on pain, function, edema changes, and follow-up surgery in bone marrow edema syndrome of the proximal femur. Methods: A systematic literature search up to May 2022 was performed to find relevant papers that made a statement about the outcome of intravenous iloprost therapy alone. Factors such as the Visual Analog Scale (VAS), Harris Hip Score (HHS), edema reduction, and follow-up interventions were considered. These were compared using Forest plots. Results: In 11 studies, 190 proximal femora with bone marrow edema syndrome that received intravenous iloprost therapy without further therapeutic intravenous or surgical intervention such as core decompression were studied. There was a significant mean improvement in VAS by 3.3 cm (2.07−4.5 cm) (p < 0.001) and HHS by 24.36 points (18.23−30.49) (p < 0.001) 3−6 months after receiving iloprost therapy. Only in 9.3% of cases (1.1−24.3%) did no clinical or radiological improvement occur. Conclusions: It could be shown that the existing publications support intravenous therapy with iloprost in patients with bone marrow edema syndrome and result in good clinical outcomes.