This systematic review protocol is reported in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analyses Protocols (PRISMA-P) guidelines (8), and is registered with International Prospective Register of Systematic Reviews (PROSPERO) (registration number CRD42020205892). The presented systematic literature search strategy has been designed a priori by authors E.B., B.L. and P.E.B.
Data Sources
A literature search will be performed using the electronic databases PubMed, Scopus, Cochrane Library (Cochrane Central Registry of Controlled Trials and Cochrane Database of Systematic Reviews), ClinicalTrials.gov and WHO International Clinical Trials Registry Platform. The keywords used are selected from key papers to create a broad search as described in Table 1. Search strings 1 and 2 will be combined using the Boolean term AND, then the following limits will be applied: (1) Publication date prior to the date of the search, (2) English language only. In addition, the reference lists of included articles will be searched.
Table 1
Literature search strategy: search strings 1 and 2 will be combined using the Boolean term AND then the limits will be applied
Search Strategy
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1 = augmented reality OR mixed reality OR hybrid reality OR head-mounted display OR head-up display
2 = surgery OR surgeon OR surgical OR intraoperative OR navigation OR visualisation OR imaging OR training OR safety
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Limits
Publication date 1990 onwards; English language only.
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Study Selection and Analysis
A broad search strategy will be used to identify all studies investigating the intraoperative use of AR or MR. Literature search results will be managed using Mendeley Desktop (Mendeley Desktop version 1.19.6, Elsevier, Amsterdam, Netherlands). Electronic citations, including available abstracts, will be independently screened by three reviewers (E.B., J.S. and M.S.). Discrepancies will be resolved by discussion or by referral to a fourth reviewer (B.L.). Prespecified inclusion criteria are that studies report empirical data on the use of AR or MR intraoperatively.
The following will be excluded: studies using AR or MR only in the context of simulation or training; studies describing only the technique of using AR or MR in the absence of clinical data; studies reporting the use of VR in the absence of AR or MR; protocol papers; systematic reviews; meta-analyses; review articles; individual opinions such as letters or commentaries; articles not published in the English language; and studies on animal models.
Data Extraction and Analysis
The data from all articles in the final review will be extracted by three independent authors (E.B., J.S. and M.S.) using a structured, standardised proforma (Table 2) to ensure consistency in the method of appraisal of these articles. This proforma has been designed a priori and tested on two articles. Any discrepancies will be resolved by consensus or by referral to a fourth reviewer (B.L.).
Table 2
Data extraction proforma
Author
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Year
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Study design
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No. of participants
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Technology
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Device
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Ergonomics
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Manufacturer
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Cost
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Table 2 continued
Source of real data
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Source of virtual data
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Image-to-patient registration technique
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Technical challenges/
limitations
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Elective or emergency
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Adult or child
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Study context (pre- vs intraoperative)
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Speciality of operating surgeon(s)
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Procedure
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Table 2 continued
Operative time
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Postoperative complications
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Length of inpatient stay
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User satisfaction score
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Other qualitative outcomes
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Other quantitative outcomes
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Risk of Bias Assessment
Included articles will be critically appraised for methodological quality and risk of bias. The extent of discussion of individual articles in this review will be weighted according to each article’s evidence level. For each objective of this review, sources of bias will be discussed collectively.
Observational cohort studies will be assessed using the Cochrane Collaboration Risk of Bias in Non-randomised Studies – of Interventions (ROBINS-I) Tool. This will evaluate the risk of bias due to confounding, selection, measurement, and interpretation. The risk of bias assessment will be presented using a traffic-light grid in the style recommended by the Cochrane Collaboration.
Data synthesis
A narrative synthesis will be performed. This will be structured according to the core questions of the review and subcategorised by device used. We will perform subgroup analysis based upon the available data, such as differences between surgical specialities and context.
If there are three or more studies with low risk of bias and data amenable to meta-analysis, then this will be performed. We will explore sources of potential clinical and methodological heterogeneity based on the study design, population, intervention and comparator characteristics and outcomes. Statistical heterogeneity will be assessed using the chi-square test and quantified with the I2 statistic. The thresholds for interpretation of I2 will be in accordance with the definitions presented in the Cochrane Handbook for Systematic Reviews of Interventions.
Data synthesis will be performed using SPSS Statistics (SPSS Statistics software version 27.0, International Business Machines Corporation (IBM), New York, US).
The quality of evidence will be rated using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach. The GRADE analysis will be performed as per the Cochrane Handbook for Systematic Reviews of Interventions and applied for all outcomes. All studies will be ranked based on the level of evidence and graded based on the quality of evidence by three authors independently. Data will be presented in a summary of findings table.