Cited by 1Artificial Intelligence in Healthcare and EducationInformation Retrieval and Search BehaviorEthics and Social Impacts of AI

The DOI matches its Crossref record; 20 of the 20 references it cites were found in a registry or an index; 21 of the 26 sources its claims cite were checked for support.

Large Language Model Hallucinations in Spine Surgery: A Comparative Analysis of Clinician vs Patient-Level Prompts

Open access

Abstract

BACKGROUND AND OBJECTIVES: Large Language Models (LLMs) are increasingly used by healthcare professionals and patients for medical information synthesis. Unfortunately, their tendency to generate fabricated information (“hallucinations”) poses a significant risk. This study quantifies and compares citation accuracy of 5 prominent LLMs for common neurosurgical spine topics. METHODS: Five LLMs (ChatGPT, Gemini, Claude, Microsoft Copilot, and OpenEvidence) were evaluated. Ten clinician-level questions derived from North American Spine Society guidelines were posed using a prompt instructing the LLM to act as an “ experienced spine surgeon .” Ten corresponding patient-level questions were posed using a “ patient ” persona prompt. Both prompts requested a concise answer and 3 to 5 peer-reviewed references. Each citation was manually verified and scored as 2 (accurate), 1 (real but misrepresented), or 0 (fabricated). RESULTS: Performance varied significantly across models and question types. OpenEvidence, which directly indexes PubMed and requires user verification as a healthcare professional, achieved perfect accuracy. Among general purpose LLMs, Claude demonstrated the highest accuracy (average score 1.67, 78.0% accurate citations). Gemini had the lowest accuracy (average score 0.97) and the highest rate of fabrications (26.2%). All general purpose LLMs performed worse on patient-level queries. ChatGPT's accuracy score dropped from 1.83 to 1.08 for patient questions while its fabrication rate increased from 2.1% to 20.0%. Error profiles differed by model. Copilot frequently misrepresented article metadata (55.1% score-1 citations) and cited non–peer-reviewed websites (31.6%), particularly for patient questions. CONCLUSION: General purpose LLMs exhibit substantial and variable citation errors when queried on spine surgery topics. Accuracy is substantially lower for patient-facing prompts, which often yield fabricated references or nonscientific sources. While specialized, access-restricted platforms such as OpenEvidence provide high accuracy, the performance of widely accessible models highlights the need for careful verification of all LLM-generated medical information to ensure patient safety.

Overview

AI snapshot

Written from the paper’s full text.

TL;DR

This study quantified citation accuracy and hallucinations of five large language models (LLMs) for spine surgery questions using clinician-level versus patient-level prompts. General-purpose LLMs showed highly variable citation errors, with patient-level prompts substantially worsening accuracy and increasing fabricated references, while OpenEvidence achieved perfect citation accuracy.

Key findings

  • Across 481 citations, OpenEvidence had perfect accuracy (mean score 2.00; 120/120, 100% accurate). Among general-purpose LLMs, Claude was highest (mean 1.67; 78.0% accurate), followed by ChatGPT (1.45; 56.1%), Copilot (1.18; 31.6%), and Gemini lowest (0.97; 23.1% accurate) with the highest fabrication rate (26.2%).
  • Patient-level prompts significantly reduced accuracy for general-purpose LLMs: ChatGPT fell from 1.83 to 1.08 (P < .001), with fabrications rising from 2.1% to 20.0%; Gemini fell from 1.14 to 0.77 (P = .027), with fabrications rising from 2.0% to 20.0%. Claude showed a non-significant trend (1.78 vs 1.56, P = .258), and Copilot showed no significant difference (P = .494).
  • Error profiles differed by model: Copilot had the highest misrepresented-citation rate (55.1%), mostly “Other Metadata Errors” (74.1%), and cited non–peer-reviewed websites in 31.6% of total responses (48.0% for patient vs 14.6% for clinician queries). ChatGPT and Gemini score-1 errors were most often incorrect PMIDs/DOIs (87.5% and 60.6%, respectively), while Claude had the lowest score-1 rate (11.0%).

Methods

  • Five LLMs were evaluated: ChatGPT 5.0, Gemini 2.5 Flash, Claude Sonnet 4.5, Microsoft Copilot, and OpenEvidence 2.7.12, all queried in October 2025 via default public web interfaces. Twenty prompts were used: 10 clinician-level questions derived from North American Spine Society guidelines and 10 corresponding patient-level layperson questions; each requested a concise answer and 3–5 peer-reviewed references, with each query run in a separate chat session.
  • Citations were manually verified by three independent medical student reviewers using PubMed and publisher websites and scored as 2 (accurate), 1 (real but misrepresented), or 0 (fabricated). Inter-rater reliability was high (95.4% agreement; Cohen’s κ = 0.918), with discordant scores resolved by consensus with the senior author.
  • Mean accuracy scores were calculated per model and compared for clinician versus patient prompts using two-tailed Mann-Whitney U tests between models, one-tailed Mann-Whitney U tests between prompt types, and χ2 tests for error-type distributions; significance was P < .05, and no statistical testing was performed for OpenEvidence because it achieved a perfect score.

Limitations

  • The paper states that the study was conducted at a single time point, models are constantly updated, the 20 questions are not exhaustive, each query was sampled only once, and temperature or other modeling parameters were not recorded or altered. It also states that it did not evaluate the factual accuracy of the text answers themselves, only the quality of supporting citations.
  • The text makes evident that only four general-purpose LLMs were compared against one specialized, access-restricted platform, and all models were queried through default public interfaces without laboratory control of retrieval, so retrieval behavior and availability may vary by platform configuration and over time.

Model-written summary. Check it against the paper before relying on it.

Integrity signals

Registry

Crossref · 10.1227/neuprac.0000000000000244

Cites

20 of 20 references verified0 citation errors · 0 not checkable

Statistics

Nothing to recompute.

Figures

FIGURE 1. Direct comparison of mean accuracy citation scores between models.
FIGURE 1. Direct comparison of mean accuracy citation scores between models.CC BY-NC-ND · PubMed Central
FIGURE 2. Mean citation score of patient-level prompts compared with clinician-level prompts.
FIGURE 2. Mean citation score of patient-level prompts compared with clinician-level prompts.CC BY-NC-ND · PubMed Central
FIGURE 3. Type of errors type between patient-level prompts compared with clinician-level prompts.
FIGURE 3. Type of errors type between patient-level prompts compared with clinician-level prompts.CC BY-NC-ND · PubMed Central

Verification

Claims the paper makes

31 Own result · 10 Partly supported · 10 Own method · 9 Own interpretation · 3 Supported · 3 Not checked yet · 3 No basis given · 1 Supported so far · accuracy not yet measured

Verify all 4 references — free account

Show all 42 claims

  • It may state two separate claims as one. 16
  • Probably not a substantial claim. 15
28 of 28
  • The paper relies on this without support.

    The default, publicly available web interfaces and internet search capabilities of the LLMs reflect how typical clinicians and patients use them.

    “Accordingly, we report model performance as encountered by typical clinician and patient users, recognizing that retrieval behavior and availability may vary by platform configuration and over time.”
  • The paper relies on this without support.

    A single query per question is sufficient to characterize each model's citation accuracy.

    “In addition, each query was only sampled one time, and modeling parameters such as temperature, a parameter that controls the “randomness” or “creativity” of an AI model's output, were not explicitly recorded or altered.”
  • The paper relies on this without support.

    The 20-question bank adequately represents common spine surgery topics and typical patient inquiries.

    “Second, the list of 20 questions is not exhaustive but nonetheless represents some of the most commonly performed spine procedures.”
  • The paper relies on this without support.

    The clinician and patient prompts differ primarily in persona and not in other factors that could affect citation accuracy.

    “Two standardized, persona-driven prompts were used for respective question categories.”
  • The paper relies on this without support.

    Manual verification using PubMed and publisher websites can reliably determine whether a citation is real and whether its metadata are correct.

    “Each generated citation was manually verified by the authors using PubMed and publisher websites to confirm its existence and the accuracy of its metadata (authors, title, year, journal, PMID/DOI).”
  • The paper relies on this without support.

    The models' performance in October 2025 is relevant to current and future use.

    “This study was conducted at a single point in time, and these models are constantly being updated.”
  • The paper relies on this without support.

    The North American Spine Society guidelines are an appropriate source for clinician-level questions.

    “Questions were sourced directly from clinical guidelines published by the North American Spine Society (NASS), encompassing common procedures, including anterior cervical discectomy and fusion, lumbar laminectomy, transforaminal lumbar interbody fusion, and lumbar microdiscectomy”
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Self-check

Percentages, sums and reported differences re-computed from the paper’s own numbers.

Each contradiction between two passages listed here was confirmed by an independent check.

2 of 2

Citations

Cites

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Metadata

Authors
McLaughlin, N. D., Srinivas, A. N., Lowe, Z. F., Botterbush, K. S., Patel, M. S., & Avila, M. J.
Affiliations
Saint Louis University (US)
Corresponding author
Avila, Mauricio J.
Venue
Neurosurgery Practice
Published
2026-06
Volume
7
Issue
3
Pages
e000244-e000244
ISSN
2834-4383 (ISSN-L)
OpenAlex
W7162806514
Cited by
1
References
18
Citations by year
2026: 1
FWCI
1.99
Type
journal article
Language
en
Open access
Locations
  • Neurosurgery Open (publishedVersion, cc-by-nc-nd)
  • PubMed (publishedVersion)
  • PubMed Central (publishedVersion, cc-by-nc-nd)
Topics
  • Health Sciences › Medicine › Health Informatics › Artificial Intelligence in Healthcare and Education
  • Physical Sciences › Computer Science › Information Systems › Information Retrieval and Search Behavior
  • Physical Sciences › Computer Science › Artificial Intelligence › Ethics and Social Impacts of AI
Keywords
large language models, hallucinations, spinal surgery, citation accuracy, reference verification, OpenEvidence, ChatGPT, Claude, Gemini, Copilot, health misinformation, patient safety

About these checks

Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.

A language model drew the claims from the paper on 2026-10-30, under version 3 of the claim definition (model deepseek-v4.1-flash, prompt extract-v3).

A second model labelled each claim on 2026-10-30 (model jev-1.13-20260917, definition revision gold-guideline-v0.2).

Cited sources are checked with a language model’s help (gpt-6-sol).

Statistics and arithmetic are recomputed, not judged.

Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.

What counts as a claim ›How we measure confidence ›How we check this ›

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