Surgical drainage vs conservative treatment of odontogenic cellulitis in pediatric patients: A systematic review

The aim of this study was to compare the efficacy of two different treatment of odontogenic cellulitis in pediatric patients: conservative treatment (just intravenous antibiotic administration and tooth root treatment or tooth extraction) and surgical treatment (intravenous antibiotic administration, incision, drainage and tooth root treatment or tooth extraction). The search strategy was conducted based on the model of systematic review adopted by PRISMA guidelines. The search strategy included: Pubmed/MEDLINE, Web of Science, Scopus and Cochrane Library databases seeking clinical trials with, unless, ten pediatric patients, in English and available on-line. The key-words used in the screening were “Infection Control, Dental and Cellulitis OR odontogenic infection and cellulitis”. A total of 404 studies were obtained and the selection of manuscripts was performed based on the defined inclusion and exclusion criteria and four manuscripts were according with review. It was verified that the surgeons of these studies commonly choose the conservative treatment, varying the adherence rate between 75% and 95.2% and no complications were associated with this treatment. Likewise, 75% of the author support the conservative treatment. The conservative treatment of cellulitis in pediatric patients, presents efficacy without having to submit the patient to surgical drainage.


Introduction
Odontogenic cellulitis is an infection arising from the dentition and its adjacent supporting periodontal structure and if treatment is delayed or administered improperly, it can spread to the face, neck, brain, orbital structures, mediastinum or systemically leading to sepsis. Most of orofacial odontogenic infections originate from necrotic pulps, infected periodontal pockets, or partially erupted teeth (Chowet al., 1978;Heimdahl & Nord, 1983).
With now widely available antibiotics, better diagnostic techniques and early surgery, the mortality rate has decreased significantly over the years. Early and correct diagnosis of the true source of infection and definitive treatment of odontogenic cellulitis as soon as possible after admission may reduce the morbidity (Unkel et al., 1997).
Although, is necessary to differentiate two stages of odontogenic infection: Cellulitis and Abscess. Cellulitis is a stage of infection what overpass the periosteum and permeate to soft tissues spaces. It is a diffuse, acute, rapidly and progressive condition without defined limits which tends not to form pus and presenting mainly aerobic bacteria. If left untreated, cellulitis will evolve to an abscess or still spreading to the soft tissues and may evolve to a Ludwig's angina, cerebral abscess or sepsis.
Phlegmon is another term usually used to designate Cellulitis. Abscess is the next stage of cellulitis. It is a chronic, localized, small, well circumscribed and fluctuant stage of infection which tends to form pus and presenting mainly anaerobic bacteria (Moghimi et al., 2013;Peterson, 2003;Shanti et al., 2011).
Different clinical response of infection is expected according the age of the patient. Likewise, a different antibiotic response is age-related. Prabhash et al. (2014) found that antibiotic resistance among higher age groups is higher when compared to lower age groups. Therefore, if clinical and drug responses are different to pediatric patient compared with adults, and children seen be better responsive to antibiotics, then what should we expect of usually modalities of treatment of odontogenic cellulitis in pediatric patients?
Thus, the aim of this systematic review is compare the efficacy of two different treatment in pediatric patients with odontogenic cellulitis: conservative treatment (just intravenous antibiotic administration and tooth root treatment or tooth extraction) and the surgical treatment (intravenous antibiotic administration, incision, drainage and tooth root treatment or tooth extraction).

Registry Protocol
The search strategy was conducted based on the model of systematic review adopted by PRISMA guidelines (Moher et al., 2009). This review was registered in PROSPERO international data base of systematic reviews (CRD 42016048479).

Search strategy and selection of studies
The PICO question adopted was: "Is the conservative treatment as effective as surgical treatment to odontogenic cellulitis in pediatric patients?". It was used the Population, Interventional, Control and Outcomes (PICO) format to define an issue in comparative clinical studies involving pediatric patients with facial odontogenic cellulitis (P) undergoing to drainage (I) or not (conservative treatment) (C) and compare the efficacy of these treatments in this kind of patient (O).
To perform the search strategy it was adopted: the Pubmed/MEDLINE, Web of Science, Scopus and Cochrane Library databases seeking relevant studies being clinical trials with, unless, ten pediatric patients, in English and available online. The searches were carried out by two independent reviewers (A.H.O and C.A.A.L) for possible inclusion in the review.
The key-words used in the screening were "Infection Control, Dental and Cellulitis OR odontogenic infection and cellulitis".
Firstly were obtained 277 articles from the "PubMed (MEDLINE)", 85 articles from "Web of Science", 24 articles from the Scopus and 18 articles in "Cochrane" basis. The selection of manuscripts was performed based on the defined inclusion and exclusion criteria and, at the search end; four manuscripts were according with review (Fig. 1).

Criteria of inclusion and exclusion
The works selected to be part of the review were randomized clinical trials, prospective and retrospective clinical trials in English and available on-line, with, at least, 10 pediatric patients. The elected studies had to present a sufficient data of the modalities of treatment of odontogenic cellulitis to allow a comparison between the surgical treatment (incision and drainage associated, or not, with tooth extraction or pulp treatment) and conservative treatment (just intravenous antibiotics associated, or not, with tooth extraction or pulp treatment).

Level of evidence
The studies were classified according to their level of evidence as proposed by the National Health and Medical Research Council to show their quality (Coleman et a., 2015).

Selection of the studies
To select the titles, abstracts and full articles, a Kappa test was performed, independently, by two calibrated examiners (AHO and CAAL) resulting on concordance values of k=0.81 for PubMed/MEDLINE, k=0.82 for Web of Science, k=0.85 for Scopus and k=1.0 for Cochrane, according with the inclusion and exclusion criteria.

Search on literature
The initial search for articles was conducted according to PICO and it was obtained 404 studies, which 277 were found on the database Pubmed/MEDLINE, 85 were found on Web of Science, 24 were found on the database "Scopus". 62 articles of this 404 was repeated, which was excluded resulting in 342 articles. After reading the summaries, 324 items were eliminated from the studies for not be found inside the inclusion and exclusion criteria, such as, language, clinical trials with less than 10 patients and case reports. After perusal of the 18 remaining studies it was excluded 14 more because it not provides adequate information or there was not a only pediatric patients study. Therefore, at the end of the search it was obtained 4 studies consistent with the theme (Table.1).

Study characteristics
Among the selected studies, we can observe their characteristics on Table 1, which were found three retrospectives studies (Kara et al., 2014;Lin et al., 2006;Thikkurissy et al., 2010) and one prospective study . The number of patients evaluated range from 30 to 106 and the range of age from 1 year and 1 month to 17 years-old.
The studies bring pediatric patients presenting odontogenic cellulitis who undergone to conservative or drainage treatment. The variables presented by these articles and evaluated by this study were: Number of patient, mean age, gender, principal anatomic region affected, temperature on admission, kind of treatment, length of hospital stay, principal antibiotic intravenous elected, postoperative complication, complication during conservative treatment, recommended treatment by the study and kind of study.

Analysis of evidences of conservative treatment
The studies presented a similar treatment choice tended to conservative treatment. The rate range of the conservative treatment of the evaluated studies was 75% to 95%. The length of hospital stay mean range was 2.08 ± 1.02 to 5.86 ± 3.38 but it was not separate specifying the kind of treatment, although, Thikkurissy, S et al. related that the length of hospital stay have no significant difference between the conservative and surgical treatment (Thikkurissy et al., 2010). Besides of that, 75% of the authors recommended or preferred the conservative treatment. (Table 2)

Analysis of evidences of drainage treatment
There was a convergent result about the choice of treatment. The drainage was the option just for 4,8% to 25% of the cases. Thikkurissy et al. (2010) shown no complications associated to both of treatment, but most of the studies not related clearly this information. The drainage was the recommended option, where possible, to 25% of the authors.  refer drainage in 15% of their patients, but at begin of the article, they explain that the incision and drainage were performed when "swelling was localized in one area and was fluctuant" what characterized an abscess, not cellulitis. On this way, we can affirm the author drained none of odontogenic cellulitis, just abscess. (Table 2)

Analysis of variables linking both treatments
The affected area was a consonant data being more common in 75% of the studies in upper face. Upper and lower face infection, respectively, consist of the swelling located above or below the lip line, including all intra and extraoral regions.
The most of the studies measure, on admission, a high temperature in patients. The fever rate range affected 14,28%(>37°C) to 38,67%(>38°C) of each study, meaning, n=8 and n=41 patients, respectively. The principal antibiotic elected was Clindamycin, being, in 50% of articles, the first choice and in 25% the second choice. The preferred second choice of antibiotic was Ampicillin associated with Sulbactan. (Table 3)

Discussion
Despite being ostensibly studied in the literature, odontogenic cellulitis still no absolute consensus regarding its treatment, a fact that is amplified when pediatric patients are involved. In literature, there are authors who defend conservative treatment (Chow et al., 1978;Heimdahl & Nord, 1983;Peterson, 2003;Shanti & Aziz, 2011;Moose, 1968) and others who advocate for the surgical treatment of odontogenic cellulitis Doležalová et al., 2015;Heimdahl et al., 1985; de-Vicente-Rodríguez, 2004).
The authors who defend conservative therapy claim that after the removal of the cause of the infection, antibiotic therapy should be performed and wait the evolution of odontogenic cellulitis to the stage of odontogenic abscess for the drainage or spontaneous resolution. Thus, the dieresis and surgical exploration of the anatomical planes to perform the drainage, when the infection is in the stage of cellulite, could promote the spread of infection both systemically and the surrounding anatomical planes (Chow et al., 1978;Heimdahl & Nord, 1983;Peterson, 2003;Shanti & Aziz, 2011;Moose, 1968).
Surgical treatment presumes that early drainage of the infection, even in the stage of odontogenic cellulitis, is the best treatment alternative, as it would avoid the accumulation of bacteria and secretions inside the tissues and, consequently, avoid the progression of the infection to deep spaces due to the drainage path created by the installed drain and recommended to drain as early as possible Doležalová et al., 2015;Heimdahl et al., 1985;de-Vicente-Rodríguez, 2004). infections. When airway is not compromised, 62% of respondents routinely or occasionally institute a trial of intravenous antibiotics therapy before considering operative drainage. Fifty one percent of respondents say that unless 20% to 40% of their cases of retropharyngeal infections are resolve with antibiotic therapy alone. However, 22% are of the opinion that antibiotics alone are never sufficient treatment (Lalakea & Messner, 1999). In the light of this, for dentistry, it must be considered that the odontogenic cellulitis, in pediatric patients, is less systemically debilitating, inducing lower fever and white blood cell count (Unkel et al., 1997). At the present study, most of the authors adopted the conservative treatment ranging of 75% to 90% of all patients treated and most of them (75%) recommend conservative treatment too. Lin et al. (2006) explain it, affirming that dental or surgical interventions can be delayed through the proper use of antibiotics because young children have a better response to antibiotics than adults.
The prior antibiotic elected was the Clindamycin by 50% of the authors, but the others first choice was penicillin and A limitation founded in this study is the difficult to diagnose correctly a cellulitis. Some authors confound cellulite with abscess and it turns into a difficult to select the aim studies.
A data that must be considered is the success and failures attempts to treat the cellulitis: one form of success of the conservative treatment (encapsulate the infection and turn it in an abscess) and the failure of the conservative treatment must be resolve with a drainage treatment. On this way, many of surgical treatment analyzed could be a fail or a successful conservative treatment and it could be in an advanced spread stage and low responsive to antibiotics or in a localized infection and easy to resolve with surgical drainage. Although, there is no reports about this in the studies analyzed. Another limitation found was the few number of studies evaluating the treatment of cellulitis in pediatric patients (only 4) and even the majority of found were retrospective studies. Thus, additional and standardized studies are necessary to get better clinical responses, avoiding the mentioned limitations above.

Conclusion
Despite all the limitations and necessity of more studies on the subject, the studies demonstrated that the conservative treatment of odontogenic cellulitis could be a feasible option to the pediatric patients.