© The authors, 2025

Introduction

Oral Submucous Fibrosis (OSMF), a potentially malignant disorder, was described as “vidari” as a condition under the mouth and throat diseases in the ancient Indian medicine book “Shushrutha” [1]. In 1952, Schwartz reported a case for the first time and called it as “Atropica idiopathica mucosae oris”. Joshi coined the term “Oral Submucous Fibrosis” (OSMF) in 1953 and later in 1966, Jens J. Pindborg defined OSMF as “an insidious, chronic disease that affects any part of the oral cavity and sometimes the pharynx. Although occasionally preceded by, or associated with, the formation of vesicles, it is always associated with a juxta epithelial inflammatory reaction followed by fibroelastic change of the lamina propria and epithelial atrophy that leads to stiffness of the oral mucosa and causes trismus and an inability to eat” [2].

OSMF is globally accepted as an Indian disease due to its high prevalence in the Indian subcontinent [3]. Globally, the pooled prevalence of OSMF is 4.47%, and 6.36% in India. Chewing areca nuts is considered the major risk factor for OSMF, and the other risk factors include vitamin B, C, and iron deficiencies, consumption of spicy foods, human papillomavirus (HPV) infection, and genetic mutations [4].

Arecoline from betel nuts and copper causes inflammation, fibroblast dysfunction, and abnormal collagen deposition leading to progressive fibrosis and trismus. Other features include burning sensation, vesicle formation, reduced movement and depapillation of the tongue, blanching and leathery texture of the oral mucosa, progressive reduction of mouth opening, and shrunken uvula [5,6].

Literature reveals high morbidity and high malignant transformation rate in OSMF, thereby constant efforts have been made to develop effective management [6]. The treatment of OSMF mainly depends on the stage of the disease. Therapeutic management mainly aims to alleviate the signs and symptoms of OSMF like burning sensation and release of the fibrotic bands to assist oral opening. Stage I and II OSMF are treated with medical treatment, such as Steroids, Hyaluronidase, Collagenase, Placental extracts, Chymotrypsin, Interferon (IFN)-gamma, Aloe vera, Turmeric, Pentoxifylline, Lycopene, Beta-Carotene, Alpha-Lipoic Acid (LA), Alpha-Tocopherol, Micronutrients and minerals including iron, copper, calcium, zinc, magnesium, and selenium, as well as vitamins A, B, C, D, and E [5–7].

The treatments of OSMF were aimed at improving the patient's quality of life, but none of them has resulted in a cure for the disease. Nevertheless, surgical options are preferred in stage III and IV OSMF, cases non-responsive to medicinal therapy and cases with dysplastic or neoplastic alterations. Excision of fibrous bands (fibrotomy) alone or with grafts (split-thickness skin graft, superficial temporal fascia pedicled flap, nasolabial flap and platysma myocutaneous muscle flap abdominal dermal fat graft) are the commonly tried surgical techniques [6].

The use of interpositional grafts in areas of band excision has been the most popular method of surgical intervention in OSMF. Local interpositional flaps include tongue flap, palatal island flap, split thickness skin graft (STSG), buccal fat pad (BFP), nasolabial flap (NLF), platysma myocutaenous muscle flap (PMMF), and temporalis fascia flap [6–8]. Distant flaps include abdominal dermal fat graft (ADFG), anterolateral thigh flap, and radial forearm flap.

However, each flap has its own advantages and disadvantages. Since no medical and surgical interventions have been shown to prevent recurrence or to significantly reduce malignant development, it is necessary to evaluate the effectiveness of interpositional flaps in the management of OSMF. This systematic review was conducted to evaluate which type of interpositional graft, including old and new, is effective in surgical management of advanced oral submucous fibrosis.

Material and methods

Protocol

This systematic review adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement for reporting systematic reviews. The systematic review protocol was registered on the PROSPERO platform under ID CRD42023438373.

Focused question

Which interpositional graft is effective in the surgical management of advanced oral submucous fibrosis?

The question for the current systematic review was adopted to follow the PICO criteria:

P    Patients with OSMF

I    Interpositional flaps

C    Other surgical methods

O    Primary outcome: Mouth opening, Secondary outcome: Oral commissure width

Information sources

Data search was mainly carried out through an electronic search in several renowned databases, which mainly included PubMed, Google Scholar, Scopus, Embase, EBSCO, Web of Science, Clinical Trials Registry India, The Cochrane Oral Health Group's Trials Register, The Cochrane Central Register of Controlled Trials (CENTRAL), The PROSPERO International prospective register of systematic review, and the National Institutes of Health Trials Register. The literature search was limited to articles published between January 1, 2000, and August 31, 2023, ensuring that the literature gathered provided a comprehensive picture of interpositional graft and other surgical management in the management of advanced oral submucous fibrosis. Published articles in English or those which have a detailed summary in English were included. All references of the studies included and excluded were searched for additional relevant reports.

A set of keyword combinations; “Oral Submucous Fibrosis” [MeSH term] AND “Interpositional Flap” [MeSH term] OR “OSMF” [MeSH term] AND “Surgical Management” [MeSH term] OR “Atropica idiopathica mucosae oris” [MeSH term] AND “Fibrotomy with interpositional graft” [MeSH term]) were used to search the literature in all 11 databases to ensure that all relevant articles were screened.

Eligibility criteria

The inclusion criteria were as follows:

• Original studies.

• Full-text, English-language studies.

• Randomized controlled trials and non-randomized controlled trials were included.

• Articles reporting information on interpositional graft and other surgical management in the management of advanced oral submucous fibrosis.

• Articles reporting information about the outcomes using either buccal fat pad, nasolabial flap, extended nasolabial flap, platysma myocutaneous flap, or abdominal dermal fat graft.

• Articles reporting information about the outcomes in terms of interincisal mouth opening, and oral commissural width.

The exclusion criteria were as follows:

• Systematic reviews with or without meta-analysis, case reports, case series, and expert opinions will be excluded.

• Animal research or in vitro studies.

• Studies which used the interpositional flap in the management of advanced OSMF, but there was no information about the outcome.

• Only abstracts or articles where full-text versions were not available.

• Articles available in languages other than English.

Study selection and data extraction

The final study selection followed a two-stage assessment. In the first phase, two reviewers independently reviewed the selected articles based on reading study titles and abstracts. Considering predetermined inclusion and exclusion criteria, the studies were labeled as relevant or irrelevant, and studies that did not meet the inclusion criteria were excluded.

The full text of the relevant studies was analyzed in the second and final stages and relabeled once more according to the same criteria. The discrepancies were identified and resolved through discussion with the third author when necessary.

From the finalized papers, the following information were was retrieved; (1) Study characteristics, such as the authors and the publication year, (2) Study type and sample, (3) total sample size, sample groups, intervention used, (4) follow up period, (5) The findings of the study- Primary and Additional Outcome, and (7) conclusion.

Risk of bias and quality of assessment

The validity of the included randomized controlled studies was determined by the Cochrane risk-of-bias tool; RoB 2 is structured into a fixed set of domains of bias, focusing on different aspects of trial design, conduct, and reporting. Within each domain, a series of questions (“signaling questions”) aim to elicit information about features of the trial that are relevant to the risk of bias. The bias was evaluated in the following domains; random sequence generation, allocation concealment, blinding of participants and personnel, analysis intention (blinding of outcome assessment), incomplete outcome data, selective reporting (selection of the reported results), and other types of bias not considered previously (e.g., design bias, contamination bias). Each study was classified as low, high, or unclear risk based on the scores obtained.

For Non randomized controlled studies, Joanna Briggs Institute Critical Appraisal Checklist for Quasi-Experimental Studies was used. The tool consisted of nine questions regarding the study design, with the option to answer “yes”, indicating higher quality; “no”, indicating poor quality; or “unclear”. The bias risk percentage calculation is done by the amount of “Y” that has been selected in the checklist. When “NA” was selected, this question was not considered in the calculation, according to the guidelines of the Joanna Briggs Institute. Up to 49% was a considered a high risk of bias. From 50% to 70% was moderate risk and above 70% was a low risk of bias.

Data synthesis

A narrative synthesis of the findings was provided from the included studies, structured around the type of intervention, target population characteristics, type of outcome, and intervention content. Summaries of intervention effects for each study by calculating risk ratios (for dichotomous outcomes) or standardized mean differences (for continuous outcomes) were performed. Meta-analysis was performed due to adequate availability of the data and the homogeneity of the indices.

Statistical analysis

The meta-analyses, using the random effects model, were applied with RevMan 5.4 (RevMan 5.4, The Nordic Cochrane Centre, Copenhagen). Heterogeneity was assessed by Q test and quantified with I² statistics. Data on mean & standard deviation and event frequency & total sample size were obtained from selected studies. Mouth opening among the subjects treated with any type of graft was considered as the main outcome. For analyses, if the test showed substantial heterogeneity (I² > 50%), a random effects model was applied, or else (I² ≤ 50%), a fixed effects model was used.

Results

Literature search

The kappa value was 0.95; therefore, an agreement among the 3 investigators was acceptable. Through electronic searches, 1605 articles were identified. After the duplicate removal process, 828 articles remained. The titles and abstracts of the 828 records were examined based on predefined eligibility criteria. Consequently, 780 articles were excluded because they were off-topic. The full text of the remaining 48 articles was carefully read by 2 reviewers for potential inclusion. The articles were narrowed down to 10 articles which were selected to draw the results of the systematic review. The process of study selection is documented in the PRISMA flowchart in Figure 1.

Fig. 1 Flowchart representing the process of study selection.

General characteristics of included studies

Out of a total of 10 included studies, 5 were RCT and 5 were non-RCT. The characteristics of all included studies are summarized in Table I. All the ten studies were from India and were conducted during 2009–2023. Histopathologically proven advanced OSMF cases were included in all the studies. A total of 412 OSMF patients, with male predominance and aged between 17 and 65 were included from the considered studies. The follow-up period ranges from three months to five years. Seven studies have compared the nasolabial flap and buccal fat pad. Two studies have compared nasolabial flap and platysma myocutaneous flap exclusively, and another study compared buccal fat pad and temporoparietal fascia flap.

The primary outcome, maximal mouth opening, was recorded as inter-incisal mouth opening at different time intervals with a simple calibrated ruler and recorded in millimeters. The pre and postoperative oral commissural width was measured also measured in millimeters. The follow-up period ranged from three months to five years. Other factors that patients were evaluated for include graft uptake, time taken for mucosalization, pain status, scar assessment, patient satisfaction score, thickness of masseter muscle, post-operative complications in contracted and relaxed state on ultrasonography (USG).

All the studies showed that there was an increase in the mouth opening after the surgical management. Five studies have evaluated the oral commissural width. Anehosur et al. [19] has evaluated extraoral scar by the Stony Brook Scar Assessment Scale. Three studies have concluded that nasolabial flap is superior to buccal fat pad, while one study has suggested that NLF is superior to non-vascularized abdominal dermal fat graft. Another study has concluded that buccal fat pad graft is superior to extended nasolabial flap and tongue flap (Tab. II).

Characteristics of individual studies

Agrawal et al. [20] conducted a nonrandomized controlled trial to compare the efficacy of locally available nasolabial and buccal fat pad flaps for increasing postoperative mouth opening in the reconstruction of the defect created after fibrotomy in surgically treated cases of oral submucous fibrosis (OSMF). A total of 32 advanced OSMF patients (mouth opening< 25 mm) were included in the study. 21 patients underwent closure of the surgical defect using the buccal fat pad (group 1) and 11 patients underwent closure of the surgical defect using a nasolabial flap (group 2). The mean age of the study group was 21 to 30 years, and Male-to-female ratio was 3:1. The overall increase in mouth opening at the end of month 6 compared with the preoperative value was 24.2 mm in group 2 and 19.2 mm in group 1. Reconstruction with a nasolabial flap was superior to the BFP flap for mouth opening.

Anehosur et al. [19] performed a clinical study to compare group I (buccal fat pad; BFP) and group II (nasolabial flap; NLF) for the reconstruction of intraoral defects after the release of fibrous bands in patients with OSMF. The sample participants included 30 OSMF patients 27 (90%) male and 3 (10%) female, aged 17 to 45 years. After 1 year, the mean preoperative and postoperative intercommissural distance was 52.13 mm and 58 mm in group I and 51 mm and 60 mm in group II, respectively.

Bande et al. [21] treated ten patients by release of fibrous bands, bilateral coronoidectomy, and reconstruction with an extended nasolabial flap (nasolabial group), and the other 10 by bilateral release of fibrous bands, coronoidectomy, and reconstruction with a platysma myocutaneous muscle flap (platysma group). In the nasolabial group the mean preoperative interincisal mouth opening was 12 (range 3–14) mm, and in the platysma group it was 11 (3–13). All 20 patients were given vigorous postoperative physiotherapy, and were followed up for 3 years. The interincisal mouth opening improved to 47 (35–45) mm in the nasolabial group and 48 (41–52) mm in the platysma group.

Jain et al. [22] evaluated efficacy and compared the surgical outcome of buccal fat pad and nasolabial flap in increasing postoperative mouth opening in reconstruction of the defect created after excision of fibrous bands in 10 surgically treated cases of OSMF. Group I included 5 patients who underwent closure of surgical defect using buccal fat pad and Group II included 5 patients who underwent closure of surgical defect using nasolabial flap. The average mouth opening at the end of 6 months was 32.6 mm in group II and 29 mm in group I.

Kania et al. [23] conducted a study to compare the effectiveness of non-vascularized abdominal dermal fat graft (ADFG) and vascularized nasolabial flap (NLF) in the treatment of 30 advanced oral submucous fibrosis (OSMF) cases. Parameters assessed were mouth opening (MO), graft uptake, time taken for mucosalization, pain, intercommissural distance (ICD), scar, duration of surgery (DOS), patient satisfaction, and thickness of masseter muscle on ultrasonography. At sixth month, MO improved by 22.4 and 36.2 mm in Group A and Group B, respectively.

Mehrotra et al. [9] evaluated different surgical modalities in the management of 100 OSMF patients. The patients were randomly divided into four groups; group I had buccal fat pad graft, group II had tongue flap, group III had nasolabial fold flap, and group IV had split skin graft for correction of mucosal defect created after incising the fibrous bands. Mean preoperative mouth opening was 14.82 (SD 4.38) mm and ranged between 4.00 and 25.00 mm. Mean postoperative mouth opening at 1 month in group I was 36.36 (2.64) mm, in group II 35.36 (29) mm, in group III 35.64 (2.94) mm, and in group IV 35.80 (3.24) mm.

Mukherjee, et al. [10] evaluated different surgical modalities in the management of 10 OSMF patients. 5 patients underwent reconstruction with buccal fat pad and another five patients underwent Temporoparietal Fascia Flap. After 7 days, both flaps healed nicely with complete epithelialization of the two flaps.

Patil et al. [11] evaluated the application of extended nasolabial flap versus buccal fat pad graft in the surgical management of 8 oral submucous fibrosis patients with age range from 21 to 65 years. The 8 patients were randomly divided into two groups; group 1 (reconstruction with extended nasolabial flaps) and group 2 (reconstruction with buccal fat pad graft). The mean increase in group 1 after one year of postoperative period was 21.50 mm and in group 2 was 24.75 mm.

Rai et al. [12] compared the buccal fat pad (BFP) and nasolabial flap for reconstruction of intraoral defects after release of fibrous bands in 20 patients with oral submucous fibrosis. In all 20 patients, the interincisal mouth opening was (mean) 11 mm (3–19 mm) preoperatively which improved to a mean of 42 mm (23–52 mm).

Singh et al. [13] compared buccal fat pad, nasolabial flap and platysma flap for reconstruction of the buccal mucosal defects. The study samples were divided into three groups; group A (buccal fat pad), group B (nasolabial group) and group C (platysma fap). After 1 year follow-up, patients in platysma group had significantly better mouth opening (39.84 ± 1.65 mm) compared to both buccal fat pad (36.69 ± 3.41 mm) and nasolabial groups (37.94 ± 0.43 mm). Intercommissural distance was significantly better in patients reconstructed with platysma fap (59.21 ± 0.99 mm) compared to both buccal fat pad (54.11 ± 1 mm) and nasolabial fap (56.84 ± 1.48 mm).

Risk of bias and quality assessment

Table II represents Risk of bias in non-RCT (5 studies) assessment by Joanna Briggs Institute and showed a low risk of bias. The RCT were assessed using the ROB b tool. The method of random sequence generation was reported inadequately in one study [23] and was categorized as high-risk. In two studies, the details of randomization were not mentioned and hence they were categorized as unclear risk.

The details of allocation concealment were not reported in any of the studies assessed and were categorized as high risk. The nature of the interventions did not allow participant and examiner blinding; however, knowledge of interventions to the investigator could have resulted in bias and hence be categorized as high risk. Blinding of outcome assessment was not reported in any of the studies assessed and was categorized as high risk. There were no drop-outs in any of the studies and hence termed as low risk. The studies had no bias in terms of selective reporting. Other unspecified types of bias were also considered as associated with the lack of information on sample size estimation, examiner calibration, etc. Only one study [23] mentioned sample size estimation (Fig. 2).

Fig. 2 Risk of bias in randomized controlled studies.

Meta-analysis

I. Mouth opening after 6 months between subjects treated with nasolabial flap and other types of flaps:

• For the meta-analysis, studies with outcome of mouth opening after 6 months between subjects treated with nasolabial flap and other types of flaps were considered. The meta-analysis was performed on six studies [9,11,13,20,22,23] that qualified with the required data outcome that could be analyzed quantitatively. The results of the overall comparison have been depicted as a forest plot.

• With the meta-analysis conducted for selected studies, heterogeneity was more than 50% (I² = 80%); hence, a random effect model was applied. The mouth opening after 6-months was greater in the subjects treated with nasolabial flap as compared to subjects treated with other flap designs with a mean difference of 0.56 (95% CI = −0.13 to 1.24; Z value = 1.60); however, the difference between the two groups was statistically non-significant (p = 0.11) (Fig. 3a).

• To Assess the publication bias for the sixth-month mouth opening outcome in the selected six studies, the funnel plot was performed. It showed an asymmetrical distribution of the studies, thereby indicating a greater possibility of publication bias (Fig. 3b).

II. Mouth opening after 12 months between subjects treated with nasolabial flap and other types of flaps:

• The meta-analysis was performed on four comparisons from four studies [9,11,13,19] that have qualified with the required data outcomes that could be analyzed quantitatively. The results of the overall comparison have been depicted as a forest plot (Fig. 4a).

• With the meta-analysis conducted for selected studies, heterogeneity was more than 50% (I² = 91%); hence, a random effect model was applied. The mouth opening after 12 months was greater in the subjects treated with nasolabial flap as compared to subjects treated with other flap designs with a mean difference of 0.77 (95% CI = –0.38 to 1.92; Z value = 1.32); however, the difference between the two groups was statistically non-significant (p = 0.19).

• The assessment of publication bias for mouth opening after 12 months between subjects treated with nasolabial flap and other types of flaps was performed using a funnel plot. The funnel plot showed an asymmetrical distribution of the studies, thereby indicating greater possibility of publication bias (Fig. 4b).

III. Mouth opening after 6 months between subjects treated with buccal fat pad flap and other types of flaps:

• The meta-analysis was performed on six comparisons from six studies [9–11,13,20,22] that have qualified with the required data outcomes that could be analyzed quantitatively. The results of the overall comparison have been depicted as a forest plot (Fig. 5a).

• With the meta-analysis conducted for selected studies, heterogeneity was more than 50% (I² = 63%); hence, a random effect model was applied. The mouth opening after 6-months was lower in the subjects treated with buccal fat pad flap as compared to subjects treated with other flap designs with a mean difference of −0.14 (95% CI = −0.71 to 0.42; Z value = 0.50); however, the difference between the two groups was statistically non-significant (p = 0.62).

• The assessment of publication bias for mouth opening after 6 months between subjects treated with nasolabial flap and other types of flaps was performed using a funnel plot. The funnel plot showed an asymmetrical distribution of the studies, thereby indicating a greater possibility of publication bias (Fig. 5b).

IV. Mouth opening after 12 months between subjects treated with buccal fat pad flap and other types of flaps:

• The meta-analysis was performed on four comparisons from four studies [9,11,13,19] that have qualified with the required data outcomes that could be analyzed quantitatively. The results of the overall comparison have been depicted as a forest plot (Fig. 6a).

• With the meta-analysis conducted for selected studies, heterogeneity was more than 50% (I² = 88%); hence, a random effect model was applied. The mouth opening after 12 months was lower in the subjects treated with buccal fat pad flap as compared to subjects treated with other flap designs with a mean difference of −1.17 (95% CI = −2.20 to −0.15; Z value = 2.24) and the difference between the two groups was statistically significant (p = 0.02).

• The assessment of publication bias for mouth opening after 12 months between subjects treated with buccal fat pad flap and other types of flaps was performed using a funnel plot. The funnel plot showed an asymmetrical distribution of the studies, thereby indicating greater possibility of publication bias (Fig. 6b).

Fig. 3 (a) Forest plot depicting mouth opening outcome after 6 months between subjects treated with nasolabial flap and other types of flaps; (b) Funnel plot for assessment of publication bias for mouth opening outcome after 6 months between subjects treated with nasolabial flap and other types of flaps.

Fig. 4 (a) Forest plot depicting comparison of mouth opening outcome after 12 months between subjects treated with nasolabial flap and other types of flaps; (b) Funnel plot for assessment of publication bias for mouth opening outcome after 12 months between subjects treated with nasolabial flap and other types of flaps.

Fig. 5 (a) Forest plot depicting mouth opening after 6 months between subjects treated with buccal fat pad flap and other types of flaps; (b) Funnel plot for assessment of publication bias for after 6 months between subjects treated with buccal fat pad flap and other types of flaps.

Fig. 6 (a) Forest plot depicting mouth opening after 12 months between subjects treated with buccal fat pad flap and other types of flaps. (b) Funnel plot for assessment of publication bias for after 12 months between subjects treated with buccal fat pad flap and other types of flaps.

Discussion

The management of Oral Submucous Fibrosis (OSMF) is a real challenge due to its chronic progressive nature and malignant transformation. For management of these lesions, various interventions both medicinal and surgical have been implemented. The treatments of OSMF aim to improve the patient's quality of life, but none of them has resulted in a definitive cure for the disease. Nevertheless, surgery remains the only viable option available for advanced stages of OSMF. Excision of fibrous bands (fibrotomy) alone or with grafts to cover the raw surgical defects are the commonly tried surgical techniques [6].

The search for a surgical technique that fills the intraoral raw defect appropriately has an increased success rate with decreased complications, and results in increased mouth opening has led to application of interpositional grafts after fibrotomy. It is necessary to evaluate the effectiveness of each type of interpositional flap in the management of OSMF in terms of success rate i.e., mouth opening, as each flap has its own advantages and disadvantages.

A total of 10 studies, consisting randomized and non-randomized controlled trials, were included in this systematic review which examined the use of buccal fat pad, nasolabial flap, platysma myocutaneous flap, split thickness skin graft and abdominal dermal fat graft as interpositional material in surgical management of OSMF.

All the included studies showed that there was a significant increase in mouth opening from preoperatively to postoperatively, regardless of the type of flap used. The nasolabial flap was found to be superior to other flaps in the 6th month and 12th month follow-up, however, the results were not statistically significant. Literature reveals that most of the studies using the nasolabial flap reported postoperative mouth opening of greater than 35 mm at the end of the follow up periods which ranged from 1 to 36 months [9,13–15,20]. Agarwal et al. [10] in their study have stated that nasolabial flap allowed a slow and progressive increase in mouth opening at subsequent follow-up, making it better than the buccal fat pad for the coverage of surgically treated defects in OSMF cases.

The use of the nasolabial flap for filling raw intraoral defects is well established. The nasolabial flap is easily accessible, and has a healthy vascular bed based on the inferior nasal vessels. These advantages aid in the utilization of this flap to cover almost all regions in the oral cavity, making it a justified choice for the treatment of OSMF [24]. However, intraoral hair growth was observed in most of the patients undergoing nasolabial flap in the first week postoperatively. These complications can be managed initially by regular trimming followed by epilation after 1 month [9,11,20]. Other complications include scars in the donor facial region, partial flap necrosis, temporary widening of the oral commissure, and perforation of the palate [12,21,25].

Sarvanan et al. [16] used buccal fat pad as an interpositional material in surgical management of 8 advanced OSMF cases. The authors stated that easy mobilization of the buccal fat pad, its excellent blood supply and minimal donor site morbidity makes it an ideal flap. There was no infection or other complication seen post-operatively [16–18,26,27].

Tongue flaps, a type of intraoral interpositional flap have been used to cover the buccal defects, primarily because tongue mucosa is immune to fibrosis, and it can be harvested as a pedicle, ensuring that the vascularity is maintained. However, they were found to be bulky [9,28–31]. Additionally, bilateral tongue flaps can cause severe dysphagia and carry the risk of postoperative aspiration [9,32].

Khanna et al. [33] study showed that recurrences were common with split thickness skin graft and were associated with donor site morbidities including increased sensitivity, scar formation, and unsightly appearance. Borle [34] stated that complications like contracture during healing and rejection of the graft were very high in cases where skin graft was utilized following fibrotomy.

The platysma myocutaneous flap has also been explored as a viable option. Bande et al. [21] advocate the use of platysma muscle flap over nasolabial flap as facial aesthetics are not compromised and the increase in post-operative mouth opening remained comparable in both the groups. Similarly, in another study, by Akhilesh et al. [13] comparing NLF, BFP and platysma myocutaneous flap, the latter held more promising in terms of maximal mouth opening and inter commissural width. A post-operative complication included temporary paresthesia over lateral cervical region.

The study conducted by Kania et al. [13] was the only one evaluating the use of abdominal dermal fat graft against nasolabial flap in the management of advanced OSMF cases. Girish Kumar had earlier reported the use of ADFG for restoration of soft tissue defects in the maxillofacial region. Although abdominal dermal fat graft offers an adequate amount of tissue for reconstruction and fewer aesthetic concerns, it was concluded that nasolabial flap holds better as the reconstruction option, as the results for mouth opening were statistically significant for the nasolabial flap group. A couple of cases showed recurrence of OSMF due to complete necrosis of abdominal dermal fat graft; otherwise, no other complications were reported in this group.

A total of 6 studies included in meta-analysis in this review provide information on mouth opening and complications like graft necrosis, hair growth and commissure tear. The mouth opening after 6-months and 12 months was greater in the subjects treated with nasolabial flap compared to those treated with other flap designs.

Various grafts have been used; however, no definite indications have been developed or mentioned in the literature [35–38]. Kamath et al. [8] in their systematic literature review, concluded that there were no definite protocols adopted for particular treatment modes in OSMF management. The choice of the grafts was based on the individual preferences of the surgeon, while these should be modified and guided so that highly precise evidence can be produced on treatment results which can be analyzed for future audits. However, no meta-analysis was done by the author.

Borle [34] included 7 studies in their systematic review and quantitatively stated the overall findings with respect to buccal fat pad and nasolabial flap. A meta-analysis was performed and it was concluded that there was a dearth of high-quality, long-term and large multi-centric randomized control trials to get a conclusive answer.

We’ve aimed to review all the explored options not included in previous studies, old and new, in the surgical management of advanced OSMF cases. This comprehensive review highlights the diversity of approaches and the ongoing need for high-quality research to determine the most effective treatments. The current findings underscore the importance of tailored surgical strategies that consider the individual patient's condition, the specific characteristics of each graft or flap, and the potential complications associated with each technique. As the field evolves, future studies should focus on developing standardized treatment protocols and conducting large-scale, multi-center trials to provide clearer guidance for clinicians.

Limitations and strengths

One of the major limitations of this study is the heterogeneity of the included studies, follow up time, and other parameters used in the included studies. The continuation of the areca nut chewing postoperatively was not mentioned in any studies. Few studies have not reported the complications.

Despite these limitations, all the included studies were from India, hence there was no diversity in sample size, age, gender and duration of follow-up. The present study is the first systematic appraisal to exclusively review the effectiveness of interpositional flaps in the surgical management of advanced OSMF cases.

Conclusion

The surgical treatment of OSMF primarily aims at releasing the trismus caused by the fibrotic bands and maintenance of mouth opening in the postoperative period. The present systematic review analyzed various studies utilizing interpositional flaps used for management of advanced OSMF cases.

The use of interpositional grafts shows promising outcomes in terms of increased mouth opening and oral commissural width. However, the efficacy of different types of grafts varies. This systematic review and meta-analysis suggest that the nasolabial flap may offer superior results compared to other graft types, although the differences are not always statistically significant. Other grafts like BFP, STSG, platysma myocutaneous flap and ADFG have also been excellent choices in raw defect filling, relieving trismus, and increasing the mouth opening. Minor complications of these surgical procedures are reported, however, it outweigh the improvement in quality of life of the patient.

Only through such rigorous studies can we achieve a definitive answer and potentially establish a standardized treatment protocol for advanced OSMF. The observations of this review can help enhance awareness among the healthcare professionals, and clinicians about recommending interpositional graft in advanced OSMF cases making the best use of its advantages. We recommend future research with appropriate study designs comparing interpositional flaps with other flaps.

Funding

This article did not receive any specific funding.

Conflicts of interest

The authors declare that they have no conflict of interest.

Data availability statement

All data generated or analyzed during this study are included in this published article and its supplementary information files. As this is a systematic review, no new datasets were created. Data search was mainly carried out through an electronic search in several renowned databases, which mainly included PubMed, Google Scholar, Scopus, Embase, EBSCO, Web of Science, Clinical Trials Registry India, The Cochrane Oral Health Group's Trials Register, The Cochrane Central Register of Controlled Trials (CENTRAL), The PROSPERO International prospective register of systematic review, and the National Institutes of Health Trials Register.

Ethics approval

Ethical approval was not required for this study, as it is a systematic review based on previously published research data and does not involve human participants or animal subjects.

Informed consent

Informed consent is not applicable for this study, as it did not involve human participants.

References

All Tables

All Figures

	Fig. 1 Flowchart representing the process of study selection.
In the text

	Fig. 2 Risk of bias in randomized controlled studies.
In the text

	Fig. 3 (a) Forest plot depicting mouth opening outcome after 6 months between subjects treated with nasolabial flap and other types of flaps; (b) Funnel plot for assessment of publication bias for mouth opening outcome after 6 months between subjects treated with nasolabial flap and other types of flaps.
In the text

	Fig. 4 (a) Forest plot depicting comparison of mouth opening outcome after 12 months between subjects treated with nasolabial flap and other types of flaps; (b) Funnel plot for assessment of publication bias for mouth opening outcome after 12 months between subjects treated with nasolabial flap and other types of flaps.
In the text

	Fig. 5 (a) Forest plot depicting mouth opening after 6 months between subjects treated with buccal fat pad flap and other types of flaps; (b) Funnel plot for assessment of publication bias for after 6 months between subjects treated with buccal fat pad flap and other types of flaps.
In the text

	Fig. 6 (a) Forest plot depicting mouth opening after 12 months between subjects treated with buccal fat pad flap and other types of flaps. (b) Funnel plot for assessment of publication bias for after 12 months between subjects treated with buccal fat pad flap and other types of flaps.
In the text