Lateral lumbar interbody fusion surgery is an established minimally invasive fusion technique that delivers a large interbody cage via the retroperitoneal space. The anterior-to-psoas variation was advanced due to concerns with the trans-psoas technique causing injuries to the lumbar plexus and the obstruction by the iliac crest when approaching L4-5. By utilizing the corridor between the anterior vessels and the psoas, LLIF can be performed with comparable clinical and radiographic results while minimizing complications. The evolution of ATP LLIF includes lateral L5-S1 ALIF, lateral single position surgery, and technologies like navigation.
The costs associated with spine surgery represent a significant economic burden on healthcare systems. Awake anesthesia provides a potentially cost-effective alternative, but questions remain regarding its effectiveness in maintaining clinical outcomes when compared to general anesthesia. The purpose of this study was to determine if awake anesthesia reduced costs while maintaining clinical outcomes when compared to general anesthesia in patients undergoing spine surgery. A comprehensive literature search was conducted in PubMed, Web of Science, and the Cochrane Library through February 2026. Studies were included if they compared costs in USD in spine surgery patients undergoing awake vs general anesthesia. Non-comparative studies or those that reported costs in other currencies were excluded. A total of 514 unique records underwent abstract screening, and 9 records were chosen for final study inclusion. Meta-analyses were performed for outcomes reported by at least 2 studies, and statistical significance was defined as p < 0.05. After pooled analysis, awake anesthesia was associated with significantly reduced operative time (MD −14.87 min), anesthesia time (MD −35.28 min), and a shorter hospital LOS (MD −0.51 days). Additionally, anesthesia-related costs (MD −$274.52) and PACU costs (MD −$187.27) were significantly lower in the awake anesthesia group. There were no significant differences in direct costs, total costs, or complication rates between groups. Awake anesthesia for spine surgery is associated with shorter perioperative times, reduced hospital LOS, and decreases in anesthesia and PACU-related costs, while maintaining similar complication profiles to general anesthesia. However, no significant differences were found between groups in direct or total costs. Our findings suggest that although awake anesthesia provides significant cost effectiveness in spine surgery, this is likely due to significant reductions in resource utilization as opposed to direct changes in procedural expenditures.
Awake anesthesia is increasingly used in spine surgery, but its compatibility with traditional neuromonitoring remains uncertain. This review summarizes procedure-specific considerations for neuromonitoring in awake spine surgery, including the roles and limitations of EMG, SSEPs, and MEPs across decompression and fusion procedures. We also present preliminary institutional findings evaluating triggered EMG during lumbar surgery under spinal anesthesia. Understanding how anesthetic technique affects neuromonitoring feasibility and interpretation may help guide safe patient selection, procedural planning, and broader adoption of awake spine surgery.
Intraoperative neuromonitoring has played a critical role in the development and adoption of lateral lumbar interbody fusion (LLIF), yet traditional monitoring modalities have demonstrated important limitations in their ability to accurately evaluate lumbar plexus function during transpsoas access. Triggered electromyography, posterior tibial nerve somatosensory evoked potentials, and transcranial motor evoked potentials improved intraoperative safety but provided limited sensitivity, specificity, and procedural resolution for detecting clinically meaningful femoral nerve injury. As a result, surgeons frequently relied on indirect surrogate markers, including retractor duration, to estimate neurologic risk.Recent advances in neuromonitoring have shifted the field toward more anatomically relevant assessments of the neural structures at risk during LLIF. Saphenous somatosensory evoked potentials and transabdominal muscle action potentials (TMAP) provide direct evaluation of the sensory and motor components of the femoral nerve, respectively, and have demonstrated improved ability to detect neurologic stress during transpsoas surgery. Integration of TMAP within an event-based monitoring framework has enabled correlation of neuromonitoring changes with discrete procedural steps, demonstrating that neurologic stress most commonly occurs from mechanical insult rather than as a function of retractor duration alone.These advances have facilitated a transition from passive detection of neurologic compromise toward active neuromonitoring-guided technique refinement. Identification of high-risk procedural steps has informed modifications in transpsoas docking strategy and has been associated with reductions in both intraoperative neuromonitoring perturbations and postoperative neurologic deficits. The evolution of neuromonitoring in LLIF therefore represents a paradigm shift from injury detection toward real-time decision-making, surgical optimization, and ultimately prevention of neurologic injury.
Awake spine surgery is a viable alternative to general anesthesia for select lumbar procedures, including decompressions and fusions. The combined use of spinal anesthesia and targeted regional nerve blocks allows operations to be performed under moderate sedation while preserving patient comfort, hemodynamic stability, and airway safety. This approach reduces postoperative pain, shortens hospital stays, and lowers perioperative complications.1–3 Building on existing enhanced recovery principles, MedStar Georgetown University Hospital has developed a structured protocol emphasizing preoperative analgesia, intraoperative stability, and postoperative pain management. This manuscript outlines patient selection, anesthetic considerations, and a stepwise perioperative methodology to optimize safety and recovery.
This chapter provides a broad overview of awake endoscopic spine surgery using regional or local anesthesia with minimally invasive endoscopic approaches. It reviews the historical development, physiologic and anesthetic foundations, and key technological advances that have enabled its clinical adoption, along with indications, contraindications, patient selection, and future advancements in this field.
Lateral lumbar interbody fusion has evolved from early efforts to reduce the morbidity of traditional posterior and anterior lumbar approaches into a versatile platform for minimally invasive spine surgery. The introduction of the lateral transpsoas corridor, followed by the development of dedicated retractors, directional electromyographic neuromonitoring, and approach-specific interbody implants, enabled safe and reproducible access to the lumbar disc space. Recognition of approach-related neurologic complications subsequently drove refinement of patient selection and the development of alternative anterior-to-psoas and oblique corridors. Over time, advances in navigation, robotics, expandable implants, and alignment planning expanded the role of lateral surgery from degenerative disease to complex adult spinal deformity and anterior column realignment. More recently, lateral and prone singleposition techniques have further optimized operative workflow. The history of lateral spine surgery reflects the progressive integration of anatomical insight, technological innovation, and procedural refinement into a fully functional surgical approach.
Interest is surging in applications of artificial intelligence (AI) for automated measurement of spinopelvic parameters in patients with spine disorders. More than three-quarters of scientific papers citing the development of new AI-enabled algorithms have been published in the last five years, driven by spine surgeon demand for alternatives to manual measurement methods that are time consuming to apply and prone to significant inter- and intra-observer variability. The rapid evolution of AI technologies for automated spinopelvic measurement yields great promise, as published validation studies demonstrate continuous improvements in accuracy and reliability and substantial reductions in measurement time compared to manual and semi-automated methods. However, the absence of standardized protocols for landmark placement, vertebral labeling, and measurement reporting along with the limited availability of external ground truth data and consensus-based guidance on statistical reporting impede external validation, generalizability, comparison of algorithm performance, and widespread adoption. The development of publicly available, multi-institutional databases of ground truth data as well as expert-led standardization initiatives that promote harmonized measurement methods and reporting will ideally allow automated algorithms to reach their full clinical potential.
Adult spinal deformity affects upwards of two-thirds of adults over age 60. Definitive management for symptomatic patients involves multilevel instrumented fusion, which almost uniformly involves instrumentation to the pelvis given the improved purchase relative to that offered by the cancellous sacral bone. However, in a fraction of patients there can be loss of pelvic fixation, manifest as distal hardware breakage, screw fracture, or even sacral insufficiency fracture. Such occurrences have a significant negative impact on patient quality-of-life and often involve expensive operative revisions. In the present review we examine the prevalence and risk factors for pelvic fixation failure, examine the biomechanics of commonly employed pelvic fixation strategies, and highlight potential strategies for avoiding pelvic fixation failure.
Pelvic incidence (PI) has traditionally been considered a fixed parameter that governs sagittal spinal alignment. However, recent literature suggests that PI changes following adult spinal deformity (ASD) surgery. Recent evidence suggests that PI variability stems from sacroiliac joint motion, and is magnified by age, and postural effects. A systemic review calculated that 46% of patients exhibited PI changes after ASD surgery. The use of sacroalar iliac screws (S2AI) has been shown to decrease PI, while patients with high PI have demonstrated a decrease postoperatively. Many factors lead to PI changes; understanding these is important for surgical planning and complication prevention.
The lumbosacral junction is an area of high biomechanical demand and particularly vulnerable following long-segment adult spinal deformity surgery. However, acute failure of the pelvic implants occurring within 6 months of the index procedure, associated risk factors and potential strategies for mitigating this risk have not been widely reported. This review will address the prevalence of acute pelvic fixation failure, anatomical and biomechanical characteristics of the lumbosacral junction, known failure risk factors, and associated surgical management strategies to help reduce the rate of failure.
This case report describes lateral minimally invasive sacroiliac (SI) joint fusion for SI joint–mediated pain in a patient with a history of adult spinal deformity surgery. A 48-year-old woman with multiple medical comorbidities previously underwent long thoracolumbar fusion with subsequent L4-S1 anterior lumbar interbody fusion and posterior L4-pelvis instrumentation in 2010. Following a ground-level fall in 05/2021, she developed new left-sided hip and sacroiliac pain with intermittent left lower-extremity numbness. Radiographs demonstrated mild hip osteoarthritis and sacroiliac joint sclerosis; spine imaging revealed discontinuity of the right iliac fixation rod without acute fracture. MRI of the hip showed bilateral sacroiliitis in the setting of ankylosing spondylitis. Three image-guided SI joint injections produced significant but transient pain relief, whereas medications and physical therapy did not provide durable improvement. Given the concordant clinical presentation, imaging, and positive diagnostic block response, the patient underwent left minimally invasive lateral SI joint fusion on 10/21/2021 without complications. She was discharged on postoperative day three with improved pain and resolution of radicular symptoms. At six-month follow-up, she reported sustained functional gains and improved mobility. This case highlights the importance of confirming SI joint–mediated pain after prior spinal fusion, the role of image-guided injections in diagnosis, and the potential effectiveness of lateral minimally invasive SI joint fusion in patients with limited response to nonoperative management.
Introduction Pelvic fixation is standard in adult spinal deformity (ASD) surgery constructs which span the lumbosacral junction, yet distal mechanical failure and sacroiliac joint (SIJ) pain remain problematic. Adjunctive SIJ fusion is increasingly used to address these issues, but data on its safety and outcomes are limited. Methods We performed a retrospective review of a prospectively maintained single-institution ASD database. Consecutive patients over 18 years of age undergoing elective long-segment reconstruction (≥4 levels) with multipoint pelvic fixation (MPF), defined as ≥2 fixation points on a side, and open posterior SIJ fusion during the index surgery were included. Baseline demographics, preoperative SIJ pain (posterior superior iliac spine pain ≥4/10), and Oswestry Disability Index (ODI) were recorded. One-year clinical and radiographic outcomes were assessed, including spinopelvic alignment, persistence of SIJ pain, mechanical integrity of pelvic instrumentation, and lumbosacral fusion grading on CT when available. Results Sixty-one patients met inclusion criteria. All had radiographic follow-up, with 39 (64%) completing 1-year imaging and 49 (80%) clinical follow-up (mean 0.97 years). Mean age was 66.2 years and 69% were female. Preoperatively, 67% reported SIJ pain and mean ODI was 46.3. At 1 year, ODI improved to 30.2 (p<0.001) and SIJ pain decreased to 8%. Alignment correction was maintained (LL 32°→47°, SVA 83.7→45.4 mm, coronal Cobb 23.6°→11.8°). No rod or set screw failures occurred. Five patients (8%) had distal pelvic screw lucency. Among those with CT, 87% demonstrated definite or probable lumbosacral fusion. Conclusions Open SIJ fusion with porous titanium implants in ASD surgery was safe, improved disability and SIJ pain, and demonstrated low distal mechanical complications at 1 year follow-up.
S1 screw failures are a common complication in lumbo-pelvic spinal fusions. Anatomical and biomechanical features of the lumbosacral junction present intrinsic challenges to achieving robust fixation and solid fusion in these cases. A number of modifiable and non-modifiable risk factors exist, including patient bone quality, fusion construct length, and regional alignment, that also can influence S1 screw failures. Various mitigation strategies can help reduce strain on sacral fixation and reduce rates of S1 screw failure, such as utilization of interbody devices, iliac fixation, and cement augmentation. Failure is typically detected on plain radiographs or computed tomography by evidence of a “haloing” around the screw, fracture of screw, or a set cap dislodgement. If symptomatic from a neurological, pain, or alignment standpoint, revision surgery is often required. Currently, investigative efforts by the Spinopelvic Study Group (SPSG) are underway to gain further insights into the rates and risk factors of S1 screw fixation in short segment lumbar fusions.
The SI joint is responsible for symptoms in 15- 30% of patients presenting with lower back pain. SI joint pain lacks pathognomonic clinical exam findings or radiographic hallmarks and cannot be ruled out by the presence of normal imaging findings. This review will address the prevalence of SI joint pain, anatomical, pathological and biomechanical characteristics of the SI joint, physical exam findings, and diagnostic injection variability. Because there is not both a highly specific and highly sensitive diagnostic tool for SI joint-mediated pain, the clinician must retain a variety of investigative tools as well as high index of suspicion in order to reach the correct diagnosis.
Intervertebral disc degeneration (IDD) underlies a substantial portion of chronic low back pain and remains a major cause of disability worldwide. The intervertebral disc, composed of the nucleus pulposus, annulus fibrosus, and cartilaginous endplates, maintains spinal flexibility and distributes mechanical load. Degeneration disrupts this system through cellular dysfunction, loss of hydration, and matrix breakdown. Recent evidence characterizes IDD as a multifactorial biologic cascade rather than a single age-related process. Aging, inflammation, genetic predisposition, abnormal loading, postural malalignment, and lifestyle exposures interact through overlapping pathways that accelerate cellular senescence, oxidative stress, and extracellular matrix degradation. These mechanisms reinforce one another, producing progressive biochemical and structural failure of the disc. Although the sequence of events remains incompletely defined, advances in molecular biology and biomechanics have clarified key drivers of degeneration and identified therapeutic targets. Translational efforts are increasingly directed toward modifying these pathways through biologic and regenerative approaches, including stem cell and extracellular vesicle therapy, gene-based interventions, platelet-rich plasma, growth factors, and tissue-engineered scaffolds. Together, these discoveries support a growing view of IDD as a biologically modifiable disease and highlight the potential for mechanism-based interventions to restore disc function and prevent progression.
Artificial intelligence (AI) is rapidly reshaping modern healthcare, and spine surgery represents one of its most promising frontiers. This narrative review synthesizes current evidence on how AI technologies are being applied throughout the perioperative continuum of spine surgery, from diagnosis and preoperative planning to intraoperative guidance and postoperative care. Machine learning, deep learning, natural language processing, and computer vision have demonstrated strong performance in preoperative applications, such as automating imaging interpretation, identifying surgical candidates, optimizing implant selection, and predicting complications. Intraoperatively, AI supports navigation accuracy, augmented and mixed reality visualization, and adaptive robotic systems that respond to real-time anatomic variation. Postoperatively, predictive models forecast outcomes and complications with greater precision than traditional risk tools, while wearable sensors and telehealth platforms enable continuous monitoring and personalized recovery.While early results are promising, key challenges remain regarding data privacy, model bias, generalizability, and clinician acceptance. Ongoing efforts to validate, regulate, and ethically implement AI systems will determine their readiness for clinical translation. Ultimately, AI holds the potential to make spine surgery more predictive, precise, and patient-centered, bridging data science with surgical expertise to advance quality and safety in care delivery.
Omics technologies have transformed spine research by enabling comprehensive molecular characterization of genetic, epigenetic, transcriptomic, proteomic, and microbial factors that drive spinal disease. The purpose of this review is to synthesize current applications of omics in elucidating the mechanisms of spinal pathology and to highlight how integrated multi-omics approaches are advancing precision spine medicine. Genomic and epigenomic studies have clarified hereditary and regulatory influences on spine morphology and disease susceptibility, while transcriptomic and proteomic analyses reveal dynamic changes in gene and protein expression that mediate cellular stress, extracellular matrix remodeling, and pain signaling. Microbiomic research has identified potential microbial contributions to disc degeneration and chronic pain. Multi-omics integration now unites these molecular layers to uncover interacting pathways that underlie complex conditions including intervertebral disc degeneration, scoliosis, and ankylosing spondylitis. These advances are accelerating biomarker discovery and therapeutic target identification, fostering mechanism-based, patient-specific interventions. Ongoing challenges include data harmonization, cohort heterogeneity, and integration of omic data with biobanking and electronic health records. As computational modeling and machine learning converge with longitudinal omic datasets, spine research is poised to move from descriptive molecular mapping to actionable, personalized diagnosis and treatment.
Biologics have become central to modern spine surgery, providing tools to enhance fusion and promote biologic healing. Autologous bone graft remains the gold standard for its osteogenic, osteoinductive, and osteoconductive properties, while allografts and demineralized bone matrices expand graft availability and reduce morbidity, albeit with variability in biologic potency. Recombinant bone morphogenetic proteins offer potent osteoinduction and have demonstrated high fusion rates in challenging cases, though dose-related complications and cost have limited use. Advances in materials science have produced synthetic grafts and bioactive ceramics that provide consistent structure and surface-mediated biologic activity. Newer bioengineered constructs, including peptide-enhanced and nanosynthetic formulations, aim to combine osteoconductive scaffolds with molecular or cellular activation. Emerging therapies such as mesenchymal stem cell allografts and gene therapy seek to biologically stimulate bone formation and regeneration at the fusion site. Collectively, these biologics represent a shift from purely structural grafts toward integrated biologic systems that combine mechanical support with targeted molecular activity. Understanding their mechanisms, indications, and limitations is essential to optimize graft selection and advance biologically driven spine surgery.
Small animal models are foundational tools in translational spine surgery research, enabling investigation of disease mechanisms and preclinical evaluation of therapeutic strategies before human application. This narrative review synthesizes current knowledge on mouse, rat, and rabbit models used across major spinal pathologies, including intervertebral disc degeneration, spinal fusion, spinal cord injury, scoliosis, and osteoporotic vertebral disease. For each application, representative experimental methods, principal outcome measures, and the aspects of human pathology most accurately reproduced by these models are summarized.While these models have driven significant advances in spine research, important considerations influence their clinical translation. Quadrupedal biomechanics, persistent notochordal cells, and technical scale limitations may affect degeneration, implant performance, and repair capacity compared with humans. Additionally, variability in methodology and inconsistent reporting can limit reproducibility and inflate perceived treatment effects.Emerging approaches including genetic engineering, bioelectronic monitoring, and artificial intelligence–enhanced analytics are rapidly improving model fidelity and data quality, positioning small animal research to better support translational decision-making. Continued refinement of biological relevance, standardization of experimental rigor, and ethical stewardship will be essential to maximize the value of these systems in advancing future spine surgery innovations.
