Performance of Artificial Intelligence Chatbots on Glaucoma Questions Adapted From Patient Brochures.

Introduction With the potential for artificial intelligence (AI) chatbots to serve as the primary source of glaucoma information to patients, it is essential to characterize the information that chatbots provide such that providers can tailor discussions, anticipate patient concerns, and identify misleading information. Therefore, the purpose of this study was to evaluate glaucoma information from AI chatbots, including ChatGPT-4, Bard, and Bing, by analyzing response accuracy, comprehensiveness, readability, word count, and character count in comparison to each other and glaucoma-related American Academy of Ophthalmology (AAO) patient materials. Methods Section headers from AAO glaucoma-related patient education brochures were adapted into question form and asked five times to each AI chatbot (ChatGPT-4, Bard, and Bing). Two sets of responses from each chatbot were used to evaluate the accuracy of AI chatbot responses and AAO brochure information, and the comprehensiveness of AI chatbot responses compared to the AAO brochure information, scored 1-5 by three independent glaucoma-trained ophthalmologists. Readability (assessed with Flesch-Kincaid Grade Level (FKGL), corresponding to the United States school grade levels), word count, and character count were determined for all chatbot responses and AAO brochure sections. Results Accuracy scores for AAO, ChatGPT, Bing, and Bard were 4.84, 4.26, 4.53, and 3.53, respectively. On direct comparison, AAO was more accurate than ChatGPT (p=0.002), and Bard was the least accurate (Bard versus AAO, p<0.001; Bard versus ChatGPT, p<0.002; Bard versus Bing, p=0.001). ChatGPT had the most comprehensive responses (ChatGPT versus Bing, p<0.001; ChatGPT versus Bard p=0.008), with comprehensiveness scores for ChatGPT, Bing, and Bard at 3.32, 2.16, and 2.79, respectively. AAO information and Bard responses were at the most accessible readability levels (AAO versus ChatGPT, AAO versus Bing, Bard versus ChatGPT, Bard versus Bing, all p<0.0001), with readability levels for AAO, ChatGPT, Bing, and Bard at 8.11, 13.01, 11.73, and 7.90, respectively. Bing responses had the lowest word and character count. Conclusion AI chatbot responses varied in accuracy, comprehensiveness, and readability. With accuracy scores and comprehensiveness below that of AAO brochures and elevated readability levels, AI chatbots require improvements to be a more useful supplementary source of glaucoma information for patients. Physicians must be aware of these limitations such that patients are asked about existing knowledge and questions and are then provided with clarifying and comprehensive information.

Cell therapy for retinal disease.

PURPOSE OF REVIEW: This review presents an update on completed stem cell therapy trials aimed at retinal diseases. RECENT FINDINGS: In recent years, several clinical trials have been conducted examining the safety and role of cell therapy in diseases, including age-related macular degeneration, Stargardt's macular dystrophy, and retinitis pigmentosa. Studies have utilized a variety of cell lines, modes of delivery, and immunosuppressive regimens. The prevalence of fraudulent cell therapy clinics poses threats to patients. SUMMARY: Clinical trials have begun to characterize the safety of cell therapy in retinal disease. While studies have described the potential benefits of cell therapy, larger studies powered to evaluate this efficacy are required to continue progressing toward preventing retinal disease. Nonapproved cell therapy clinics require regulation and patient education to avoid patient complications.

Does the Severity of Foraminal Stenosis Impact Outcomes of Lumbar Decompression Surgery?

OBJECTIVE: To establish the relationship between the magnitude of foraminal stenosis and 1) improvement in patient-reported outcomes, 2) improvement in motor function after lumbar decompression surgery, and 3) difference in surgical outcomes. METHODS: Patients who underwent one-level posterior lumbar decompression for radiculopathy were retrospectively identified. Patient demographics and surgical characteristics were collected through a query search and manual chart review of the electronic medical records. Foraminal stenosis was determined on magnetic resonance imaging and graded using Lee et al.'s validated methodology as none, mild, moderate, or severe. Surgical outcomes, motor function, and patient-reported outcome measures (PROMs) were compared based on the amount of stenosis (mild vs. moderate vs. severe). Bivariant and multivariant analyses were performed. RESULTS: Severe stenosis demonstrated more 90-day readmissions (0.00% vs. 0.00% vs. 8.57%, respectively, P = 0.019), though this effect did not remain significant on multivariate analysis (P = 0.068). There was no association between stenosis severity and the degree of functional impairment or PROMs preoperatively. Patients with moderate or severe preoperative foraminal stenosis showed improvement in all PROMs after surgery (P < 0.05) except the mental component of the Short Form 12 survey. Notably, central stenosis grade was insignificantly different between groups (P = 0.358). Multivariable logistic regression analysis did not identify any significant independent predictors of surgical outcomes or changes in PROMs. CONCLUSIONS: We demonstrated that regardless of foraminal stenosis severity preoperatively, patients have a similar improvement in PROMs, surgical outcomes, and restoration of motor function after lumbar decompression surgery for radiculopathy.

Data Heterogeneity in Meta-Analyses: Statistical Methods, Interpretation, and Guidance.

Data heterogeneity determines whether sufficiently strong conclusions can be derived from synthesizing and aggregating the available literature. Multiple tools are available to calculate data heterogeneity, but each tool has pros and cons. Providing a prediction interval may be the most beneficial since it allows readers to quantify heterogeneity in a clear and clinically relevant form. However, the ultimate decision on which tool to use is left to the discretion of the researcher. This decision should be decided upon during the study inception.

Predictors of Blood Transfusion in Patients Undergoing Lumbar Spinal Fusion.

OBJECTIVE: To determine risk factors for perioperative blood transfusion after lumbar fusion surgery. METHODS: After institutional review board approval, a retrospective cohort study of adult patients who underwent lumbar fusion at a single, urban tertiary academic center was retrospectively retrieved. Our primary outcome, blood transfusion, was collected via chart query. A receiver operating characteristic curve was used to evaluate the regression model. A P-value < 0.05 was considered statistically significant. RESULTS: Of the 3,842 patients, 282 (7.3%) required a blood transfusion. For patients undergoing posterolateral decompression and fusion, predictors of transfusion included age (P < 0.001) and more levels fused (P < 0.001). A higher preoperative hemoglobin level (P < 0.001) and revision surgery (P = 0.005) were protective of blood transfusion. For patients undergoing transforaminal lumbar interbody fusion, greater Elixhauser comorbidity index (P < 0.001), longer operative time (P = 0.040), and more levels fused (P = 0.030) were independent predictors of the need for blood transfusion. Patients with a higher body mass index (P = 0.012) and preoperative hemoglobin level (P < 0.001) had a reduced likelihood of receiving a transfusion. For circumferential fusion, greater age (P = 0.006) and longer operative times (P = 0.015) were independent predictors of blood transfusion, while a higher preoperative hemoglobin level (P < 0.001) and male sex (P = 0.002) were protective. CONCLUSIONS: Our analysis identified older age, lower body mass index, greater Elixhauser comorbidity index, longer operative duration, more levels fused, and lower preoperative hemoglobin levels as independent predictors of requiring a blood transfusion following lumbar spinal fusion. Different surgical approaches were not found to be associated with transfusion.

Varenicline mitigates the increased risk of pseudarthrosis associated with nicotine.

BACKGROUND CONTEXT: High serum nicotine levels increase the risk of nonunion after spinal fusion. Varenicline, a pharmaceutical adjunct for smoking cessation, is a partial agonist designed to displace and outcompete nicotine at its receptor binding site, thereby limiting downstream activation. Given its mechanism, varenicline may have therapeutic benefits in mitigating nonunion for active smokers undergoing spinal fusion. PURPOSE: To compare fusion rate and fusion mass characteristics between cohorts receiving nicotine, varenicline, or concurrent nicotine and varenicline after lumbar fusion. STUDY DESIGN: Rodent noninstrumented spinal fusion model. METHODS: Sixty eight-week-old male Sprague-Dawley rats weighing approximately 300 grams underwent L4-5 posterolateral fusion (PLF) surgery. Four experimental groups (control: C, nicotine: N, varenicline: V, and combined: NV [nicotine and varenicline]) were included for analysis. Treatment groups received nicotine, varenicline, or a combination of nicotine and varenicline delivered through subcutaneous osmotic pumps beginning two weeks before surgery until the time of sacrifice at age 14 weeks. Manual palpation testing, microCT imaging, bone histomorphometry, and biomechanical testing were performed on harvested spinal fusion segments. RESULTS: Control (p=0.016) and combined (p=0.032) groups, when compared directly to the nicotine group, demonstrated significantly greater manual palpation scores. The fusion rate in the control (93.3%) and combined (93.3%) groups were significantly greater than that of the nicotine group (33.3%) (p=0.007, both). Biomechanical testing demonstrated greater Young's modulus of the fusion segment in the control (17.1 MPa) and combined groups (34.5 MPa) compared to the nicotine group (8.07 MPa) (p<0.001, both). MicroCT analysis demonstrated greater bone volume fraction (C:0.35 vs N:0.26 vs NV:0.33) (p<0.001, all) and bone mineral density (C:335 vs N:262 vs NV:328 mg Ha/cm3) (p<0.001, all) in the control and combined groups compared to the nicotine group. Histomorphometry demonstrated a greater mineral apposition rate in the combined group compared to the nicotine group (0.34 vs 0.24 µm/day, p=0.025). CONCLUSION: In a rodent spinal fusion model, varenicline mitigates the adverse effects of high nicotine serum levels on the rate and quality of spinal fusion. CLINICAL SIGNIFICANCE: These findings have the potential to significantly impact clinical practice guidelines and the use of pharmacotherapy for active nicotine users undergoing fusion surgery.

Is disc height loss at 1 year predictive of pseudarthrosis and patient-reported outcome measures following anterior cervical discectomy and fusion with structural allograft?

OBJECTIVE: The authors sought to determine if postoperative disc height loss is associated with pseudarthrosis following anterior cervical discectomy and fusion (ACDF). They also sought to determine if the amount of postoperative disc height loss is predictive of need for revision for pseudarthrosis, as well as the impact of postoperative disc height loss on patient-reported outcome measures (PROMs) following surgery. METHODS: The authors retrospectively identified patients aged > 18 years who underwent primary one- to three-level ACDF with allograft at a single institution with 1-year postoperative lateral and flexion-extension cervical spine radiographs. Logistic regression models and receiver operating characteristic curves were used for analysis. Alpha was set at p < 0.05. RESULTS: Anterior or posterior disc height loss ≥ 2 mm was found in 52.5% of patients. Patients with a loss ≥ 2 mm were more likely to develop pseudarthrosis (p = 0.021) but not to undergo revision surgery due to pseudarthrosis (p = 0.459). Multivariable analysis identified male sex (OR 1.66, p = 0.013), the number of levels fused (OR 2.09, p < 0.001), and fusion at C6-7 (OR 1.52, p = 0.043) as predictors of disc height loss. The analysis also revealed that levels at the top (OR 0.383, 95% CI 0.170-0.854, p = 0.020) and middle (OR 0.174, 95% CI 0.053-0.548, p = 0.003) of fusion constructs were significant independent predictors of lower pseudarthrosis rates while disc height loss was not. Patients with disc height loss had significantly less improvement in scores for the Neck Disability Index (p = 0.002), visual analog scale (VAS) for arm pain (p = 0.018), and VAS for neck pain (p = 0.011) at 1 year following surgery. CONCLUSIONS: This study is, to the authors' knowledge, the largest study to date to assess the impact of postoperative disc height loss after ACDF. Disc height loss following ACDF was not predictive of revision surgery for pseudarthrosis or overall pseudarthrosis rates. However, pseudarthrosis was less likely to occur at the top and middle of fusion constructs. Loss in disc height postoperatively was significantly associated with less improvement in PROMs.

The impact of cage positioning on lumbar lordosis and disc space restoration following minimally invasive lateral lumbar interbody fusion.

OBJECTIVE: The objective of this study was to evaluate patient and surgical factors that predict increased overall lumbar lordosis (LL) and segmental lordosis correction following a minimally invasive lateral lumbar interbody fusion (LLIF) procedure. METHODS: A retrospective review was conducted of all patients who underwent one- or two-level LLIF. Preoperative, initial postoperative, and 6-month postoperative measurements of LL, segmental lordosis, anterior disc height, and posterior disc height were collected from standing lateral radiographs for each patient. Cage placement was measured utilizing the center point ratio (CPR) on immediate postoperative radiographs. Spearman correlations were used to assess associations between cage lordosis and radiographic parameters. Multivariate linear regression was performed to assess independent predictors of outcomes. RESULTS: A total of 106 levels in 78 unique patients were included. Most procedures involved fusion of one level (n = 50, 64.1%), most commonly L3-4 (46.2%). Despite no differences in baseline segmental lordosis, patients with anteriorly or centrally placed cages experienced the greatest segmental lordosis correction immediately (mean anterior 4.81° and central 4.46° vs posterior 2.47°, p = 0.0315) and at 6 months postoperatively, and patients with anteriorly placed cages had greater overall lordosis correction postoperatively (mean 6.30°, p = 0.0338). At the 6-month follow-up, patients with anteriorly placed cages experienced the greatest increase in anterior disc height (mean anterior 6.24 mm vs posterior 3.69 mm, p = 0.0122). Cages placed more posteriorly increased the change in posterior disc height postoperatively (mean posterior 4.91 mm vs anterior 1.80 mm, p = 0.0001) and at 6 months (mean posterior 4.18 mm vs anterior 2.06 mm, p = 0.0255). There were no correlations between cage lordotic angle and outcomes. On multivariate regression, anterior cage placement predicted greater 6-month improvement in segmental lordosis, while posterior placement predicted greater 6-month improvement in posterior disc height. Percutaneous screw placement, cage lordotic angle, and cage height did not independently predict any radiographic outcomes. CONCLUSIONS: LLIF procedures reliably improve LL and increase intervertebral disc space. Anterior cage placement improves the lordosis angle greater than posterior placement, which better corrects sagittal alignment, but there is still a significant improvement in lordosis even with a posteriorly placed cage. Posterior cage placement provides greater restoration in posterior disc space height, maximizing indirect decompression, but even the anteriorly placed cages provided indirect decompression. Cage parameters including cage height, lordosis angle, and material do not impact radiographic improvement.

Impact of surface roughness and bulk porosity on spinal interbody implants.

Spinal fusion surgeries are performed to treat a multitude of cervical and lumbar diseases that lead to pain and disability. Spinal interbody fusion involves inserting a cage between the spinal vertebrae, and is often utilized for indirect neurologic decompression, correction of spinal alignment, anterior column stability, and increased fusion rate. The long-term success of interbody fusion relies on complete osseointegration between the implant surface and vertebral end plates. Titanium (Ti)-based alloys and polyetheretherketone (PEEK) interbody cages represent the most commonly utilized materials and provide sufficient mechanics and biocompatibility to assist in fusion. However, modification to the surface and bulk characteristics of these materials has been shown to maximize osseointegration and long-term stability. Specifically, the introduction of intrinsic porosity and surface roughness has been shown to affect spinal interbody mechanics, vascularization, osteoblast attachment, and ingrowth potential. This narrative review synthesizes the mechanical, in vitro, in vivo, and clinical effects on fusion efficacy associated with introduction of porosity in Ti (neat and alloy) and PEEK intervertebral implants.

The Usefulness of Closed Incision Negative Pressure Wound Therapy After Spinal Fusion: A Systematic Review and Meta-Analysis.

OBJECTIVE: To determine if closed incision negative pressure wound therapy (ciNPWT) decreases surgical site infection (SSI) or wound dehiscence after spinal fusion. METHODS: Following PRISMA guidelines, a systematic review and meta-analysis were conducted to identify studies using ciNPWT after spinal fusion. Funnel plots and quality scores of the articles were performed to determine if the articles were at risk of bias. Forest plots were conducted to identify the treatment effect of ciNPWT after spinal fusion. RESULTS: A total of 8 studies comprising 1061 patients who received ciNPWT or a standard postoperative dressing after spinal fusion were included. The rate of SSI (ciNPWT, 4.49% [95% confidence interval (CI), 2.48-8.00] vs. control, 11.32% [95% CI, 7.51-16.70]; P = 0.0103) was significantly lower for patients treated with ciNPWT. A fixed-effects model showed no significant difference between patients who received ciNWPT or a standard postoperative dressing with respect to requiring reoperations for wound debridement (odds ratio, 1.25; 95% CI, 0.64-2.41). In addition, wound dehiscence was not significantly different between the 2 groups, although it was nonsignificantly lower in ciNWPT-treated patients (ciNPWT, 4.59% [95% CI, 2.49-8.31] vs. control: 7.48% [95% CI, 4.38-12.47]; P = 0.23). CONCLUSIONS: ciNPWT may reduce the rates of SSI after spinal fusion. The use of ciNWPT may also significantly reduce the burden associated with postoperative wound complications, but the meta-analysis was insufficiently powered to make this association. Additional studies may identify a subset of patients who benefit from ciNPWT for other wound-related complications.

Patients with Dual Shoulder-Spine Disease: Does Operative Order Affect Clinical Outcomes?

OBJECTIVE: 1) To analyze the effect of operative sequence (anterior cervical discectomy and fusion [ACDF] first or rotator cuff repair [RCR] first) on surgical outcomes after both procedures for patients with dual shoulder-spine injuries and 2) to determine how operative sequence affects patient-reported outcome measures (PROMs) after surgery. METHODS: Patients >18 years of age who underwent primary ACDF and primary RCR at our institution were retrospectively identified. Only patients with overlapping symptoms before the first procedure were included. Patients were divided into 2 cohorts (ACDF first or RCR first). Patient demographics, surgical characteristics, surgical outcomes, and PROMs were compared between groups. Multivariate linear regression models were developed to determine if operative order was predictive of improvements in PROM scores at the 1-year postoperative point after the second procedure. Alpha was set at P < 0.05. RESULTS: Of the 85 patients included, 44 patients (51.8%) underwent ACDF first, whereas 41 patients (48.2%) underwent RCR first. There were no significant differences in the rate of 90-day readmission, spine reoperations, and rotator cuff reoperations between groups (all, P > 0.05). Multivariate linear regression showed that undergoing an ACDF first was not a significant predictor of Δ Mental Component Score of the Short-Form 12 (ß = -2.78; P = 0.626) and Δ Physical Component Score of the Short-Form 12 (ß = 7.74; P = 0.077) at the 1-year postoperative point after the second procedure. CONCLUSIONS: For patients with dual shoulder-spine injuries who are appropriate surgical candidates, undergoing ACDF first compared with RCR first does not result in significant differences in clinical surgical or patient-reported outcomes.

Effect of Fellow Involvement and Experience on Patient Outcomes in Spine Surgery.

INTRODUCTION: Investigations in spine surgery have demonstrated that trainee involvement correlates with increased surgical time, readmissions, and revision surgeries; however, the specific effects of spine fellow involvement remain unelucidated. This study aims to investigate the isolated effect of fellow involvement on surgical timing and patient-reported outcomes measures (PROMs) after spine surgery and evaluate how surgical outcomes differ by fellow experience. METHODS: All patients aged 18 years or older who underwent primary or revision decompression or fusion for degenerative diseases and/or spinal deformity between 2017 and 2019 at a single academic institution were retrospectively identified. Patient demographics, surgical factors, intraoperative timing, transfusion status, length of stay (LOS), readmissions, revision rate, and preoperative and postoperative PROMs were recorded. Surgeries were divided based on spine fellow participation status and occurrence in the start or end of fellowship training. Univariate and multivariate analyses compared outcomes across fellow involvement and fellow experience groups. RESULTS: A total of 1,108 patients were included. Age, preoperative diagnoses, number of fusion levels, and surgical approach differed markedly by fellow involvement. Fellow training experience groups differed by patient smoking status, preoperative diagnosis, and surgical approach. On univariate analysis, spine fellow involvement was associated with extended total theater time, induction start to cut time, cut to close time, and LOS. Increased spine fellow training was associated with reduced cut to close time and LOS. On regression, fellow involvement predicted cut to close extension while increased fellow training experience predicted reduction in cut to close time, both independent of surgical factors and assisting residents or physician assistants. Transfusions, readmissions, revision rate, and PROMs did not differ markedly by fellow involvement or experience. CONCLUSION: Spine fellow participation predicted extended procedural duration. However, the presence of a spine fellow did not affect long-term postoperative outcomes. Furthermore, increased fellow training experience predicted decreased procedural time, underscoring a learning effect. AVAILABILITY OF DATA AND MATERIAL: The data sets generated during and/or analyzed during the current study are available from the corresponding author on reasonable request. LEVEL OF EVIDENCE: Level 3.

Do Inflammatory Cytokines Affect Patient Outcomes After ACDF?

STUDY DESIGN: Prospective cohort study. OBJECTIVE: The aim was to determine the relationship between serum inflammatory mediators, preoperative cervical spine disease severity, and clinical outcomes after anterior cervical discectomy and fusion (ACDF). SUMMARY OF BACKGROUND DATA: Given the role of the inflammatory cascade in spinal degenerative disease, it has been hypothesized that inflammatory markers may serve as a predictor of patient outcomes after surgery. MATERIALS AND METHODS: All patients over age 18 who underwent ACDF for cervical spondylosis with associated radiculopathy and/or myelopathy between 2015 and 2017 from a single institution were prospectively recruited. Preoperative serum inflammatory markers including interleukin (IL)-6, IL-8, tumor necrosis factor-α, high-mobility group box-1 (HMGB1), and white blood cells were measured and correlated to patient demographics, surgical characteristics, duration of symptoms, previous opioid use, and preoperative and 1-year postoperative patient-reported outcomes measures (PROMs) including the neck disability index (NDI), visual analog scale neck pain, visual analog scale arm pain, and Physical and Mental Component Scores of the Short Form-12 (PCS and MCS, respectively) using spearman's rho coefficient. RESULTS: A total of 77 patients were enrolled with follow-up PROMs available for 62% (n=48) of patients at a minimum of 1-year after ACDF. The absolute concentrations of IL-6 and tumor necrosis factor-α were found to be weakly correlated with one another (ρ=0.479). Preoperative symptoms lasting <1-year were weakly correlated with elevation in HMGB1 (ρ=0.421). All other patient demographics exhibited negligible correlation with the preoperative inflammatory markers. Lower preoperative PCS (ρ=0.355) and higher preoperative NDI (ρ=0.336) were weakly correlated with elevated HMGB1. Lower MCS (ρ=0.395) and higher NDI (ρ=0.317) preoperatively were weakly correlated with elevated white blood cells. Postoperative improvement in MCS (ρ=0.306) and MCS recovery ratio (ρ=0.321) exhibited a weakly positive correlation with IL-6. CONCLUSION: Preoperative cytokine levels demonstrated minimal correlation with preoperative symptoms or clinical improvement, suggesting that profiling of patient cytokines has limited utility in predicting outcomes after ACDF. LEVEL OF EVIDENCE: Level III.