A comprehensive, structured literature search of published articles is conducted. This is designed by the author S.S and performed in adherence to the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA), the standardized PRISMA-P checklist can be found in the supplementary material (9).
2.1 Data sources
The literature search is performed using the electronic databases MEDLINE (PubMed), EMBASE and Web of Science. The keywords used in the search are selected from key papers and are described in tables below. Search strings 1 and 2 are combined using the Boolean term AND, then the limits are applied. Furthermore, a ‘MeSH term’ search is conducted, and the reference lists of included articles are reviewed for any additional articles.
Search strategy for Embase.com (15.04.2020)
/exp = EMtree keyword with explosion
.tw = The Textword field in EMBASE includes Title (TI) and Abstract (AB).
Table 1- Search Strategy used in EMBASE
Number
|
Search terms
|
Results
|
#1
|
exp plastic surgery/ OR exp surgeon/ OR exp plastic surgeon/ OR exp esthetic surgery/ OR exp skin transplantation/ OR exp microsurgery/ OR exp tissue flap/ OR exp Z plasty/ OR exp surgical flaps/ OR exp reconstructive surgery/ OR exp face surgery/ OR exp maxillofacial surgery/ OR exp oral surgery/ OR skin graft*.tw. OR full thickness graft*.tw. OR SSG.tw. or FTG.tw OR axial flap*.tw. OR pedicled flap*.tw. OR surgical flap*.tw. OR contracture release*.tw. OR exp free tissue graft/ OR free flap*.tw. OR regional flap*.tw. OR exp skin flap/ OR local flap*.tw. OR surger*.tw. OR surgical*.tw. OR operation*.tw. OR operative*.tw. OR incisi*.tw. OR excisi*.tw. OR management*.tw. OR treatment.tw
|
8557452
|
#2
|
Exp Vincent stomatitis/ OR acute necrotizing ulcerative gingivitis.tw OR acute necrotising ulcerative gingivitis.tw OR acute ulcerative gintivitis.tw OR noma.tw OR cancrum oris.tw
|
1401
|
#3
|
#1 AND #2
|
639
|
Limits: Publication prior to final search, April 15th, 2020
|
Source: Authors table
Search strategy for MEDLINE (PubMed) (15.04.2020)
/exp = MEDLINE keyword with explosion/ Mesh terms
.tw = The Textword field in MEDLINE includes Title (TI) and Abstract (AB).
Table 2- Search Stratedy used in MEDLINE
Number
|
Search terms
|
Results
|
#1
|
exp Reconstructive Surgical Procedures/ OR exp Surgery, Plastic/ OR exp Tissue Transplantation/ OR exp Surgical Flaps/ OR exp Skin Transplantation/ ORexp Free Tissue Flaps/ OR exp Microsurgery/ OR exp Surgery, Oral/ OR exp Surgical Procedures, Operative/ OR exp "Oral and Maxillofacial Surgeons"/ OR exp Surgeons/ OR skin graft*.tw. OR full thickness graft*.tw. OR SSG.tw. OR FTG.tw. OR axial flap*.tw. OR pedicle flap*.tw. OR pedicled flap*.tw. OR surgical flap*.tw. OR contracture release*.tw. OR free flap*.tw. OR regional flap*.tw. OR local flap*.tw. OR surger*.tw. OR surgical*.tw. OR operation*.tw. OR operative*.tw. OR incisi*.tw. OR excisi*.tw. OR management*.tw. OR treatment*.tw
|
8167413
|
#2
|
exp Noma/ OR cancrum oris.tw. OR exp Gingivitis, Necrotizing Ulcerative/ OR acute necrotizing ulcerative gingivitis.tw. OR acute necrotising ulcerative gingivitis.tw.
|
1664
|
#3
|
#1 AND #2
|
568
|
Limits: Publication prior to final search, April 15th, 2020
|
Source: Authors table
Search strategy for Clarivate Analytics/Web of Science (15.04.2020)
TOPIC = words in title, abstract or keywords
ndexes=SCI-EXPANDED, SSCI, A&HCI, CPCI-S, CPCI-SSH, BKCI-S, BKCI-SSH, ESCI, CCR-EXPANDED, IC Timespan=All years
Table 3- Search Strategy used in Web of Science
Number
|
Search terms
|
Results
|
#1
|
TS= (surger* OR surgical* OR surgeon* OR operation* OR operative* OR incisi* OR extracti* OR excisi* OR management* OR treatment*)
|
9,621,445
|
#2
|
TS= (reconstructi* OR cosmetic* OR esthetic* OR aesthetic* OR plastic OR corrective* OR oral* or *maxillofacial* OR facial OR face* OR "head and neck" OR flap* OR skin* or micro* )
|
8,095,337
|
#3
|
TS= (noma OR "cancrum oris" OR "necrotizing ulcerative gingivitis" OR "acute necrotizing ulcerative gingivitis" OR "acute necrotising ulcerative gingivitis")
|
3,515
|
#4
|
#2 AND #1
|
1,821,209
|
#5
|
#4 AND #3
|
186
|
Limits: Publication prior to final search, April 15th, 2020
|
The PRISMA flow chart is used to display the selection and inclusion/exclusion of articles in the screeining process, as seen below.
Source: Moher D, Shamseer L, Clarke M, Ghersi D, Liberati A, Petticrew M, et al. Preferred reporting items for systematic review and meta-analysis protocols (PRISMA-P) 2015 statement. Syst Rev. 2015;4:1.
2.2 Study eligibility criteria
Articles are eligible for inclusion if they provide primary empirical evidence of patient outcomes after NOMA surgery. The full inclusion and exclusion criteria are detailed in the table below. Study selection was independently assessed by 2 reviewers (S.S. and M.B.), any persisting disagreements were reviewed and adjudicated by a third reviewer (H.K.).
Table 5- Inclusion/exclusion criteria for study selection
Inclusion Criteria
|
1. Original publications
2. Human subjects
3. Case Series, Retrospective Data Analyses, Clinical Trials, Controlled Clinical Trials, Prospective Studies
|
Exclusion Criteria
|
1. Publication type does not match inclusion criteria (Review articles, Mixed methodology studies without subgroup data, Animal studies, Conference Articles)
2. Conditions other than NOMA, Cancrum Oris, or Necrotizing Ulcerative Stomatitis not related to NOMA
3. The paper is about conditions located at sites other than the Maxillofacial and Head and Neck region
4. The paper is not about treatment
5. The paper is not about a surgical intervention (but included if terms such as reconstruction or rehabilitation, or flap or graft, are mentioned).
6. The paper is about prevention rather than treatment of NOMA
|
Source: Authors table
2.3 Data extraction and analysis
Articles are appraised and data extracted using a structured, pro forma designed a priori from the Cochrane Collaboration’s data collection form for intervention reviews, see the table below. This data collection template is pilot tested in randomly selected articles, before being used to assess all included articles. Data extracted includes patient demographics (gender, age, comorbidities), the details of the surgical procedure used (technique, surgery time, intraoperative complications) and any outcome measures reported including time to outcome measurement and any complications (see Appendix 1).
2.4 Methodological Quality and Assessment of Bias
Article review includes analysis of study design to ascertain risk of bias. Studies are also assigned a level of evidence based on the Oxford Centre for Evidence Based Medicine (10). Included articles are rated for methodological quality using the MINORS criteria as seen in appendix 2 (11).
Table 6- Adapted form of Oxford Levels of Evidence
Level of Evidence
|
Types of Studies
|
I
|
SR (with homogeneity) of RCTs, Individual RCT (with narrow Confidence Interval),
|
II
|
SR (with homogeneity) of cohort studies, Individual cohort study (including low quality RCT; e.g., <80% follow-up), “Outcomes” Research; Ecological studie
|
III
|
SR (with homogeneity*) of case-control studies, Individual Case-Control Study
|
IV
|
Case-series (and poor quality cohort and case-control studies)
|
V
|
Expert opinion without explicit critical appraisal, or based on physiology, bench research or “first principles”
|
Source: Burns PB, Rohrich RJ, Chung KC. The levels of evidence and their role in evidence-based medicine. Plastic and reconstructive surgery. 2011;128(1):305-10.
2.5 Statistical analysis
Data are analysed using IBM SPSS statistics version 24. Descriptive statistics are performed where possible to permit for narrative synthesis. Meta-analysis is performed for outcomes of interest where at least three comparative studies, with low risk of bias, report the same outcome variable.