The Effect of Osteoporosis on Complications and Reoperation Rates After Surgical Management of Adult Thoracolumbar Spinal Deformity: A Systematic Review and Meta Analysis.

STUDY DESIGN: Systematic Review. OBJECTIVES: While substantial research has explored the impact of osteoporosis on patients undergoing adult spinal deformity (ASD) correction, the literature remains inconclusive. As such, the purpose of this study is to synthesize and analyze existing studies pertaining to osteoporosis as a predictor of postoperative outcomes in ASD surgery. METHODS: We performed a systematic review and meta-analysis to determine the effect that a diagnosis of osteoporosis, based on ICD-10 coding, dual-energy X-ray absorptiometry (DEXA) or computed tomography, has on the incidence of adverse outcomes following surgical correction of ASD. Statistical analysis was performed using Comprehensive Meta-Analysis (Version 2) using a random effects model to account for heterogeneity between studies. RESULTS: After application of inclusion and exclusion criteria, 36 and 28 articles were included in the systematic review and meta-analysis, respectively. The meta-analysis identified greater rates of screw loosening amongst osteoporotic patients (70.5% vs 31.9%, P = .009), and decreased bone mineral density in patients who developed proximal junctional kyphosis (PJK) (.69 vs .79 g/cm2, P = .001). The systematic review demonstrated significantly increased risk of any complication, reoperation, and proximal junctional failure (PJF) associated with reduced bone density. No statistical difference was observed between groups regarding fusion rates, readmission rates, and patient-reported and/or functional outcome scores. CONCLUSION: This study demonstrates a higher incidence of screw loosening, PJK, and revision surgery amongst osteoporotic ASD patients. Future investigations should explore outcomes at various follow-up intervals in order to better characterize how risk changes with time and to tailor preoperative planning based on patient-specific characteristics.

Radiographic Risk Factors for Adjacent Segment Disease Following Anterior Cervical Discectomy and Fusion (ACDF): A Systematic Review and Meta-Analysis.

STUDY DESIGN: Systematic review and meta-analysis. OBJECTIVES: To assess the radiographic risk factors for adjacent segment disease (ASD) following anterior cervical discectomy and fusion (ACDF) for degenerative cervical spine pathologies. METHODS: PubMed, Embase and the Cochrane Library databases were searched up to December 2023. The primary inclusion criteria were degenerative spinal conditions treated with ACDF, comparing radiological parameters in patients with and without postoperative ASD. The radiographic parameters included intervertebral disc height, cervical sagittal alignment, sagittal segmental alignment, range of motion, segmental height, T1 slope, sagittal vertical axis (SVA), thoracic inlet angle (TIA), and plate to disc distance (PPD). Risk of bias was assessed for all studies. The Cochrane Review Manager was utilized to perform the meta-analysis. RESULTS: From 7044 articles, 13 retrospective studies were included in the final analysis. Three studies had "not serious" bias and the other 10 studies had serious or very serious bias. The total number of patients in the included studies was 1799 patients. Five studies included single-level ACDF, 2 studies included multi-level ACDF, and 6 studies included single or multi-level ACDF. On meta-analysis, the significant risk factors associated with ASD development were reduced postoperative cervical lordosis (mean difference [MD] = 3.35°, P = .002), reduced last-follow-up cervical lordosis (MD = -3.02°, P = .0003), increased preoperative to postoperative cervical sagittal alignment change (MD = -3.68°, P = .03), and the presence of developmental cervical canal stenosis (Odds ratio [OR] = 4.17, P < .001). CONCLUSIONS: Decreased postoperative cervical lordosis, greater change in cervical sagittal alignment and developmental cervical canal stenosis were associated with an increased risk of ASD following ACDF.

Top 25 Most Cited Articles on Intraoperative Computer Tomography-Guided Navigation in Spine Surgery.

BACKGROUND: In recent years, the use of intraoperative computer tomography-guided (CT-guided) navigation has gained significant popularity among health care providers who perform minimally invasive spine surgery. This review aims to identify and analyze trends in the literature related to the widespread adoption of CT-guided navigation in spine surgery, emphasizing the shift from conventional fluoroscopy-based techniques to CT-guided navigation. METHODS: Articles pertaining to this study were identified via a database review and were hierarchically organized based on the number of citations. An "advanced document search" was performed on September 28th, 2022, utilizing Boolean search operator terms. The 25 most referenced articles were combined into a primary list after sorting results in descending order based on the total number of citations. RESULTS: The "Top 25" list for intraoperative CT-guided navigation in spine surgery cumulatively received a total of 2742 citations, with an average of 12 new citations annually. The number of citations ranged from 246 for the most cited article to 60 for the 25th most cited article. The most cited article was a paper by Siewerdsen et al., with 246 total citations, averaging 15 new citations per year. CONCLUSIONS: Intraoperative CT-guided navigation is 1 of many technological advances that is used to increase surgical accuracy, and it has become an increasingly popular alternative to conventional fluoroscopy-based techniques. Given the increasing adoption of intraoperative CT-guided navigation in spine surgery, this review provides impactful evidence for its utility in spine surgery.

Cervical Disc Arthroplasty: Rationale, Designs, and Results of Randomized Controlled Trials.

BACKGROUND: This review outlines clinical data and characteristics of current Food and Drug Administration (FDA)-approved implants in cervical disc replacement/cervical disc arthroplasty (CDR/CDA) to provide a centralized resource for spine surgeons. METHODS: Randomized controlled trials (RCTs) on CDR/CDA were identified using a search of the PubMed, Web of Science, and Google Scholar databases. The initial search identified 69 studies. Duplicates were removed, and the following inclusion criteria were applied when determining eligibility of RCTs for the current review: (1) discussing CDR/CDA prosthesis and (2) published within between 2010 and 2020. Studies without clinical data or that were not RCTs were excluded. All articles were reviewed independently by 2 authors, with the involvement of an arbitrator to facilitate consensus on any discrepancies. RESULTS: A total of 34 studies were included in the final review. Findings were synthesized into a comprehensive table describing key features and clinical results for each FDA-approved CDR/CDA implant and are overall suggestive of expanding indications and increasing utilization. CONCLUSIONS: RCTs have provided substantial evidence to support CDR/CDA for treating single- and 2-level cervical degenerative disc disease in place of conventional anterior cervical discectomy and fusion. CLINICAL RELEVANCE: This review provides a resource that consolidates relevant clinical data for current FDA-approved implants to help spine surgeons make an informed decision during preoperative planning.

Analysis of Complications in Multilevel Anterior Cervical Discectomy and Fusion Using Osteobiologics Other than Bone Morphogenetic Protein: A Systematic Review.

STUDY DESIGN: Systematic review. OBJECTIVES: The aim of this study is to analyze the complications related to multilevel anterior cervical discectomy and fusion (ACDF) using osteobiologics other than bone morphogenetic protein (BMP). METHODS: A systematic review of the literature was conducted using PubMed, EMBASE, Cochrane Library, and ClinicalTrials.gov databases. The search to identify studies reporting complications in multilevel ACDF surgery using osteobiologics other than bone morphogenetic protein was performed in August 2020. The study was reported in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA). RESULTS: A total of 584 articles were found after searching the databases and removing duplicates. Next, screening was performed in a double reviewer process, and 153 eligible articles-with 4 retrospective studies-in full-text were selected; these met all inclusion criteria. A total of 197 patients received 3-level ACDF, while 72 patients received 4-level ACDF. Osteobiologics were used in all selected articles, allograft was used in 4 studies, autologous bone graft was utilized in 3 articles, and hydroxyapatite was used in 1 article. The main complications reported were dysphagia, adjacent segment disease, and pseudarthrosis. CONCLUSIONS: Given the limited evidence, no conclusions on complications in multilevel ACDF using osteobiologics other than BMP could be made. However, descriptively, the most common complications found were dysphagia, adjacent segment disease, and pseudoarthrosis. Further prospective studies separately analyzing complications in multilevel ACDF by osteobiologics and a number of treated levels are needed.

Complications of the Use Allograft in 1- or 2-Level Anterior Cervical Discectomy and Fusion: A Systematic Review.

Study Design: Systematic literature reviewObjective: To critically analyze the literature and describe the complications associated with the use of allograft in 1- or 2- level anterior cervical discectomy and fusion (ACDF)Methods: A systematic search of PubMed/MEDLINE, EMBASE, and ClinicalTrials.gov databases was conducted for literature published between January 2000 and August 2020 reporting complications associated with the use of allograft in 1- or 2- level ACDF.Results: From 584 potentially relevant citations, 21 met the inclusion criteria (4 randomized controlled trials (RCT), 4 prospective, and 13 retrospective studies). The patient number varied between 26 and 463 in comparative studies (RCT and non-RCT) and between 29 and 345 in non-comparative studies. Fusion rate was reported in 14 studies and ranged between 68.5-100%. The most frequently reported complication was post-operative dysphagia or dysphonia, with incidences ranging between .5% and 14.4%. Revision surgery was the second most reported complication (14 studies) and ranged between 0% and 10.3%. Wound-related complications were reported in 6 studies and ranged between 0% and 22.8%.Conclusion: The overall reporting of complications was low with very few comparative studies. Reported complications with allografts are within the range of other osteobiologics and autografts and in most cases may not attributable to the use of osteobiologics and may be complications of the procedure itself. Comparative studies with a more robust methodology analyzing complications with allograft and other osteobiologics are needed to inform current practice with strong recommendations.

Development of an International AO Spine Guideline for the Use of Osteobiologics in Anterior Cervical Fusion and Decompression (AO-GO).

STUDY DESIGN: Methodological study for guideline development. OBJECTIVE: AO Spine Guideline for Using Osteobiologics (AO-GO) project for spine degenerative pathologies was an international, multidisciplinary collaborative initiative to identify and evaluate evidence on existing use of osteobiologics in Anterior Cervical Fusion and Decompression (ACDF). The aim was to formulate precisely defined, clinically relevant and internationally applicable guidelines ensuring evidence-based, safe and effective use of osteobiologics, considering regional preferences and cost-effectiveness. METHODS: Guideline was completed in two phases: Phase 1- evidence synthesis; Phase 2- recommendation development based on the Grading of Recommendations, Assessment, Development and Evaluations (GRADE) approach. In Phase 1, key questions identified by a panel of experts were addressed in a series of systematic reviews of randomized and non-randomized studies. In Phase 2, the GRADE approach was used to formulate a series of recommendations, including expert panel discussions via web calls and face-to-face meetings. DISCUSSION: AO-GO aims to bridge an important gap between evidence and use of osteobiologics in spine fusion surgeries. Owing to differences in osteobiologics preparation and functional characteristics, regulatory requirements for approval may vary, therefore it is highly likely that these products enter market without quality clinical trials. With a holistic approach the guideline aims to facilitate evidence-based, patient-oriented decision-making processes in clinical practice, thus stimulating further evidence-based studies regarding osteobiologics usage in spine surgeries. In Phase 3, the guideline will be disseminated and validated using prospectively collected clinical data in a separate effort of the AO Spine Knowledge Forum Degenerative in a global multicenter clinical study.

The Evidence for the Use of Osteobiologics in Hybrid Constructs (Anterior Cervical Discectomy and Fusion and Total Disc Replacement) in Multilevel Cervical Degenerative Disc Disease: A Systematic Review.

STUDY DESIGN: Systematic review. OBJECTIVE: Examine the clinical evidence for the use of osteobiologics in hybrid surgery (combined anterior cervical discectomy and fusion (ACDF) and total disc replacement (TDR)) in patients with multilevel cervical degenerative disc disease (DDD). METHODS: PubMed and Embase were searched between January 2000 and August 2020. Clinical studies investigating 18-80 year old patients with multilevel cervical DDD who underwent hybrid surgery with or without the use of osteobiologics were considered eligible. Two reviewers independently screened and assessed the identified articles. The methodological index for non-randomized studies (MINORS) tool and the risk of bias (RoB 2.0) assessment tool were used to assess risk of bias. The Grading of Recommendations, Assessment, Development and Evaluations (GRADE) was used to evaluate quality of evidence across studies per outcome. RESULTS: Eleven studies were included. A decrease in cervical range of motion was observed in most studies for both the hybrid surgery and the control groups consisting of stand-alone ACDF or TDR. Fusion rates of 70-100% were reported in both the hybrid surgery and control groups consisting of stand-alone ACDF. The hybrid surgery group performed better or comparable to the control group in terms of adjacent segment degeneration. Studies reported an improvement in visual analogue scale for pain and neck disability index values after surgery compared to preoperative scores for both treatment groups. The included studies had moderate methodological quality. CONCLUSIONS: There is insufficient evidence for assessing the use of osteobiologics in multilevel hybrid surgery and additional high quality and controlled research is deemed essential.

The Role of Osteobiologics in Augmenting Spine Fusion in Unplated Anterior Cervical Discectomy and Fusion Compared to Plated Constructs: A Systematic Review and Meta-analysis.

STUDY DESIGN: Systematic review and meta-analysis. OBJECTIVE: To compare clinical and radiographic outcomes as well as complications of unplated vs plated anterior cervical discectomy and fusion (ACDF) surgery considering the role of osteobiologics in single- and multi-level procedures. METHODS: A systematic search of PubMed/MEDLINE, Scopus, CINAHL, EMBASE, CENTRAL, Cochrane and ClinicalTrials.gov databases was performed. Briefly, we sought to identify studies comparing unplated vs. plated ACDF for cervical degenerative disc disease reporting the use of osteobiologics in terms of clinical outcomes, radiographic fusion, and complications. Data on study population, follow-up time, type of cage and plate used, type of osteobiologic employed, number of levels treated, patient-reported outcomes (PROs), radiographic outcomes and complications were collected and compared. Relevant information was pooled for meta-analyses. RESULTS: Thirty-eight studies met the inclusion criteria. No significant difference was found in terms of clinical outcomes between groups. Unplated ACDF was characterized by reduced blood loss, operation time and length of hospital stay. Fusion was achieved by the majority of patients in both groups, with no evidence of any specific contribution depending on the osteobiologics used. Dysphagia was more commonly associated with anterior plating, while cage subsidence prevailed in the unplated group. CONCLUSION: Unplated and plated ACDF seem to provide similar outcomes irrespective of the osteobiologic used, with minor differences with doubtful clinical significance. However, the heterogeneity and high risk of bias affecting included studies markedly prevent significant conclusions.

AO Spine Guideline for the Use of Osteobiologics (AOGO) in Anterior Cervical Discectomy and Fusion for Spinal Degenerative Cases.

STUDY DESIGN: Guideline. OBJECTIVES: To develop an international guideline (AOGO) about the use of osteobiologics in anterior cervical discectomy and fusion (ACDF) for treating degenerative spine conditions. METHODS: The guideline development process was guided by AO Spine Knowledge Forum Degenerative (KF Degen) and followed the Guideline International Network McMaster Guideline Development Checklist. The process involved 73 participants with expertise in degenerative spine diseases and surgery from 22 countries. Fifteen systematic reviews were conducted addressing respective key topics and evidence was collected. The methodologist compiled the evidence into GRADE Evidence-to-Decision frameworks. Guideline panel members judged the outcomes and other criteria and made the final recommendations through consensus. RESULTS: Five conditional recommendations were created. A conditional recommendation is about the use of allograft, autograft or a cage with an osteobiologic in primary ACDF surgery. Other conditional recommendations are about the use of osteobiologic for single- or multi-level ACDF, and for hybrid construct surgery. It is suggested that surgeons use other osteobiologics rather than human bone morphogenetic protein-2 (BMP-2) in common clinical situations. Surgeons are recommended to choose 1 graft over another or 1 osteobiologic over another primarily based on clinical situation, and the costs and availability of the materials. CONCLUSION: This AOGO guideline is the first to provide recommendations for the use of osteobiologics in ACDF. Despite the comprehensive searches for evidence, there were few studies completed with small sample sizes and primarily as case series with inherent risks of bias. Therefore, high-quality clinical evidence is demanded to improve the guideline.

Do Osteobiologics Augment Fusion in Anterior Cervical Discectomy and Fusion Surgery Performed With Mechanical Interbody Devices (Polyether ether ketone, Carbon Fiber, Metal Cages) and is the Fusion Rate Comparable to that With Autograft? A Systematic Review.

STUDY DESIGN: Systematic Review of the Literature. OBJECTIVE: The purpose of this study was to perform a systematic review describing fusion rates for anterior cervical discectomy and fusion (ACDF) using autograft vs various interbody devices augmented with different osteobiologic materials. METHODS: A systematic review limited to the English language was performed in Medline, Embase and Cochrane library using Medical Subject Heading (MeSH) terms. Studies that evaluated fusion after ACDF using autografts and osteobiologics combined with PEEK, carbon fibre, or metal cages were searched for. Articles in full text that met the criteria were included in the review. The main outcomes evaluated were the time taken to merge, the definition of the fusion assessment, and the modality of the fusion assessment. The risk of bias of each article was assessed by the MINORS score or ROB 2.0 depending on the randomisation process. RESULTS: The total number of references reviewed was six hundred and eighty-two. After applying the inclusion criteria, 54 were selected for the retrieval of the full text. Eight studies were selected and included for final analysis in this study. Fusion rates were reported between 83.3% and 100% for autograft groups compared to 46.5% and 100% for various interbody device/osteobiological combinations. The overall quality of the evidence in all radiographic fusion studies was considered insufficient due to a serious risk of bias. CONCLUSION: Mechanical interbody devices augmented with osteobiologics performed similarly to autografts in terms of reliability and efficacy. Their time to fusion and fusion rate were comparable to autografts at the end of the final follow-up.

Complications With Demineralized Bone Matrix, Hydroxyapatite and Beta-Tricalcium Phosphate in Single and Two-Level Anterior Cervical Discectomy and Fusion Surgery.

STUDY DESIGN: Systematic literature review. OBJECTIVES: To analyze the evidence available reporting complications in single or two-level anterior cervical discectomy and fusion (ACDF) using a demineralized bone matrix (DBM), hydroxyapatite (HA), or beta-tricalcium phosphate (ß-TCP). METHODS: A systematic review of the literature using PubMed, EMBASE, Cochrane Library, and ClinicalTrials.gov databases was performed in August 2020 to identify studies reporting complications in one or two-level ACDF surgery using DBM, HA, or ß-TCP. The study was reported following the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines. RESULTS: A total of 1857 patients were included, 981 male and 876 female, across 17 articles; 5 prospective, and 12 retrospectives. We noted heterogeneity among the included studies concerning the study design and combination of graft materials utilized in them. However, we noted a higher incidence of adjacent segment disease (17.7%) and pseudoarthrosis (9.3%) in fusion constructs using DBM. Studies using ß-TCP reported a higher incidence of pseudoarthrosis (28.2%) and implant failures (17.9%). CONCLUSIONS: Degenerative cervical conditions treated with one or two-level ACDF surgery using DBM, HA, or ß-TCP with or without cervical plating are associated with complications such as adjacent segment disease, dysphagia, and pseudarthrosis. However, consequent to the study designs and clinical heterogeneity of the studies, it is not possible to correlate these complications accurately with any specific graft material employed. Further well-designed prospective studies are needed to correctly know the related morbidity of each graft used for achieving fusion in ACDF.

Structural Allograft Versus Mechanical Interbody Devices Augmented With Osteobiologics in Anterior Cervical Discectomy and Fusion: A Systematic Review.

STUDY DESIGN: Systematic Literature Review. OBJECTIVE: Perform a systematic review evaluating postoperative fusion rates for anterior cervical discectomy and fusion (ACDF) using structural allograft vs various interbody devices augmented with different osteobiologic materials. METHODS: Comprehensive literature search using PubMed, Embase, The Cochrane Library, and Web of Science was performed. Included studies were those that reported results of 1-4 levels ACDF using pure structural allograft compared with a mechanical interbody device augmented with an osteobiologic. Excluded studies were those that reported on ACDF with cervical corpectomy; anterior and posterior cervical fusions; circumferential (360° or 540°) fusion or revision ACDF for nonunion or other conditions. Risk of bias was determined using the Cochrane review guidelines. RESULTS: 8 articles reporting fusion rates of structural allograft and an interbody device/osteobiologic pair were included. All included studies compared fusion rates following ACDF among structural allograft vs non-allograft interbody device/osteobiologic pairs. Fusion rates were reported between 84% and 100% for structural allograft, while fusion rates for various interbody device/osteobiologic combinations ranged from 26% to 100%. Among non-allograft cage groups fusion rates varied from 73-100%. One study found PEEK cages filled with combinations of autograft, allograft, and demineralized bone matrix (DBM) to have an overall fusion rate of 26%. In one study comparing plate and zero-profile constructs, there was no difference in fusion rates for two-level fusions. CONCLUSION: There was limited data comparing fusion outcomes of patients undergoing ACDF using structural allograft vs interbody devices augmented with osteobiologic materials to support superiority of one method.

Comparison of Different Osteobiologics in Terms of Imaging Modalities and Time Frames for Fusion Assessment in Anterior Cervical Discectomy and Fusion: A Systematic Review.

STUDY DESIGN: Systematic review. OBJECTIVES: The study's primary objective was to determine how osteobiologic choice affects fusion rates in patients undergoing anterior cervical discectomy and fusion (ACDF). The study's secondary objectives were to 1) determine the optimal timing of fusion assessment following ACDF and 2) determine if osteobiologic type affects the timing and optimal modality of fusion assessment. METHODS: A systematic search of PubMed/MEDLINE was conducted for literature published from 2000 through October 2020 comparing anterior fusion in the cervical spine with various osteobiologics. Both comparative studies and case series of ≥10 patients were included. RESULTS: A total of 74 studies met the inclusion criteria. Seventeen studies evaluated the efficacy of autograft on fusion outcomes, and 23 studies assessed the efficacy of allograft on fusion outcomes. 3 studies evaluated the efficacy of demineralized bone matrix, and seven assessed the efficacy of rhBMP-2 on fusion outcomes. Other limited studies evaluated the efficacy of ceramics and bioactive glasses on fusion outcomes, and 4 assessed the efficacy of stem cell products. Most studies utilized dynamic radiographs for the assessment of fusion. Overall, there was a general lack of supportive data to determine the optimal timing of fusion assessment meaningfully or if osteobiologic type influenced fusion timing. CONCLUSIONS: Achieving fusion following ACDF appears to remain an intricate interplay between host biology and various surgical factors, including the selection of osteobiologics. While alternative osteobiologics to autograft exist and may produce acceptable fusion rates, limitations in study methodology prevent any definitive conclusions from existing literature.

Systematic Review and Meta-Analysis of the Effect of Osteoporosis on Fusion Rates and Complications Following Surgery for Degenerative Cervical Spine Pathology.

BACKGROUND: As the elderly population grows, the increasing prevalence of osteoporosis presents a unique challenge for surgeons. Decreased bone strength and quality are associated with hardware failure and impaired bone healing, which may increase the rate of revision surgery and the development of complications. The purpose of this review is to determine the impact of osteoporosis on postoperative outcomes for patients with cervical degenerative disease or deformity. METHODS: A systematic review using Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines and Medical Subject Headings terms involving spine surgery for cervical degenerative disease and osteoporosis were performed. This review focused on radiographic outcomes, as well as surgical and medical complications. RESULTS: There were 16 studies included in the degenerative group and 9 in the deformity group. Across degenerative studies, lower bone mineral density was associated with increased rates of cage subsidence in osteoporotic patients undergoing operative treatment for cervical degenerative disease. Most studies reported varied results on the relationship between osteoporosis and other outcomes such as revision and readmission rates, costs, and perioperative complications. Our meta-analysis suggests that osteoporotic patients carry a greater risk of reduced fusion rates at 6 months and 1 year postoperatively. With respect to cervical deformity correction, although individual complication rates were unchanged with osteoporosis, the collective risk of incurring any complication may be increased in patients with poor bone stock. CONCLUSIONS: Overall, the literature suggests that outcomes for osteoporotic patients after cervical spine surgery are multifactorial. Osteoporosis seems to be a significant risk factor for developing cage subsidence and pseudarthrosis postoperatively, whereas reports on medical and hospital-related metrics were inconclusive. Our findings highlight the challenges of caring for osteoporotic patients and underline the need for adequately powered studies to understand how osteoporosis changes the risk index of patients undergoing cervical spine surgery. CLINICAL RELEVANCE: In patients undergoing cervical spine surgery for degenerative disease, osteoporosis is a significant risk factor for long-term postoperative complications-notably cage subsidence and pseudarthrosis. Given the elective nature of these procedures, interdisciplinary collaboration between providers should be routinely implemented to enable medical optimization of patients prior to cervical spine surgery.