Role of early extraction of odontogenic focus in deep neck infections

Background Odontogenic deep neck infections remain a common condition that presents a challenging issue due to the complex involvement of the neck and adjacent structures and its potential life-threatening risk. Periapical infection of the second or third molar with spread to the submandibular and parapharyngeal spaces is the most commonly observed scenario. However, the time of dental extraction of the infection focus remains controversial. The aim of this study is to provide an overview of the epidemiology, clinical and radiological features, and management in patients diagnosed with ODNI and to identify the role of early dental extraction on patient outcomes and recovery. Material and Methods This retrospective study included patients over 18 years old with a diagnosis of ODNI who were admitted to the University Hospital “Dr Jose Eleuterio Gonzalez” from January 2017 to January 2022. ODNI diagnosis was based on clinical and radiological evidence of the disease supplemented by dental and maxillofacial evaluation for an odontogenic aetiology. Results A total of 68 patients were included in the study. The patients’ mean age was 40.96 ± 14.9. Diabetes mellitus was the most common comorbidity. The submandibular space was the most common deep neck space involved (n=59, 86.8%). Mediastinitis, marginal nerve injury and orocervical fistula were observed in 7.5% of patients, with no fatality in this series. A delay of >3 days for dental extraction of the involved tooth was associated with an increased rate of mediastinitis (n=3, 100%, p= 0.022), number of surgical interventions (1.45 ± 0.61, p= 0.006), ICU stay (n=8, 40%, p= 0.019), and ICU length of stay (0.85 ± 0.8, p= 0.001). Conclusions Expedited management with surgical drainage and intravenous antibiotic treatment, along with early extraction of the involved tooth, is mandatory. Key words:Odontogenic, neck infections, abscess, mediastinitis, tooth extraction.


Introduction
Deep neck infections (DNI) remain a common condition that presents a challenging issue due to the complex involvement of the neck and adjacent structures and its potential life-threatening risk (1). Although its incidence has decreased with the use of antibiotics, DNI is a cause of substantial complications, including upper airway obstruction, mediastinitis, septic shock, and vascular thrombosis, leading to significant morbidity and mortality (2). Aetiology DNI has evolved with the antibiotic era, being pharyngotonsillitis the most common cause of DNI prior to antibiotic use (3). In the present day, dental infections are a persistent cause of DNI accounting for 33 to 65% of cases (4)(5)(6). Odontogenic deep neck infections (ODNI) result mainly from periodontal diseases, periapical abscesses, and dental intervention in infected teeth. These infections have been considered an individual pathology from DNI, as ODNI display specific microbiological and treatment features (7,8). Periapical infection of the second or third molar with spread to the submandibular and parapharyngeal spaces is the most commonly observed scenario (9). However, a lack of identification of the origin of infection has been observed in 19.9% of cases (10). Despite the identification of a dental source of the infection, the time of dental extraction in ODNI remains controversial. Regardless of the worldwide increase in dental hygiene and health campaigns, ODNI continues to be a cause of neck infections and fatal complications. The aim of our study is to provide an overview of the epidemiology, clinical and radiological features, and management in patients diagnosed with ODNI and to identify the role of early dental extraction on patient outcomes and recovery.

-Subjects
This retrospective study included patients over 18 years old with a diagnosis of ODNI who were admitted to the University Hospital "Dr Jose Eleuterio Gonzalez," a tertiary referral academic hospital, from January 2017 to January 2022. Exclusion criteria included non-odontogenic DNI, pregnancy, superficial neck infections, surgical or penetrating infected neck wounds, incomplete medical records, and loss of follow-up after discharge. Patients with a history of neck surgery, head and neck cancer, radiotherapy, and chemotherapy were also excluded. The research protocol was approved by the local Research and Institutional Ethics Committee. The authors assert that all procedures contributing to this work comply with the ethical standards of the relevant national and institutional guidelines on human experimentation and with the Helsinki Declaration of 1975, as revised in 2008.
-Data collection Data were extracted from medical records using a standardized data collection form. All authors contributed to data retrieval and an independent author adjudicated any difference in interpretation between the data extractors.
-Studied variables Studied variables included demographics, alcohol, Tabaco and drug use, symptomatology, radiological findings, treatment modality, microbiological cultures, outcomes, and complications. ODNI diagnosis was based on clinical and radiological evidence of the disease supplemented by dental and maxillofacial evaluation for an odontogenic aetiology. Radiological evaluation was performed by the assessment of computed tomographies obtained from the database of the University Hospital "Dr Jose E. González" Diagnostic Radiology Department. All scans were evaluated by head and neck radiologists and otolaryngologists.
-Statistical analysis Statistical analysis was performed using SPSS V25.0 (Armonk, NY: IBM Corp). Categorical variables are reported as percentages and frequencies; continuous variables are reported as means and standard deviations. Categorical variables were compared using Pearson's x2 test or Fisher's exact test for 2 x 2 tables. An unpaired Student's t test or Mann-Whitney U test were used to compare continuous variables. P< 0.05 was considered statistically significant.
Mediastinitis, marginal nerve injury and orocervical fistula were observed in 7.5% of patients, with no fatality in this series. Overall, in 79.4% (n= 54) of patients, intrahospitalary dental extraction was performed with a mean time until extraction of 4.04 ± 3.5 days (Table 1).

Discussion
In this observational study, we found that outcomes and complications of a patient with ODNI are associated with the involved dentation and the time of dental extraction since diagnosis. Inferior molars were the most common dentation involved in ODNI, with the most frequent extension to submandibular, parapharyngeal, and masticator cervical spaces. Furthermore, a delay of >3 days for dental extraction was associated with mediastinitis, ICU admission, and ICU length of stay. Overall, the complication rate was 26.6% in the present series. Previous studies have assessed the prevalence, behaviour, and outcomes of ODNI. These infections usually result from pericoronitis and necrosis of the dental pulp with further root canal infection (11). The incidence of odontogenic infections as the leading cause of DNI varies among published evidence. However, odontogenic infections remain the principal cause of DNI (22 to 65.3%) (6,12,13). The second most common cause of DNI is debatable, with IV drug use, trauma, and upper airway infections being the most common (14). However, unknown aetiology has been reported in up to 57% of cases (15). Patients with ODNI typically present with a history of dental pain or dental procedure, followed by cervical pain, fever, oedema, dysphagia, and trismus (14). Respiratory symptomatology, such as respiratory distress and stridor, is seen in more advanced stages of the disease.  Involved teeth have been associated with outcomes and prognosis in ODNI. Mandibular odontogenic infections have been associated with the need for surgical drainage, increased hospital stay, and admission to the ICU (14). In our series, mandibular molars were the most affected teeth, accounting for 55.3% of cases. Mandibular odontogenic infections tend to extend to submandibular, buccal, parotid, and temporal space than maxillary teeth and have a greater rate of complications. Although infrequent, serious life-threatening complications can arise from ODNI, necrotizing fasciitis, sepsis, and mediastinitis being the most common. Dyspnea and dysphagia have been associated with the spread of ODNI toward deep cervical spaces and serve as an indicator of serious infections (2). ODNI was complicated by mediastinitis in 7.4% of cases in our study, similar to incidence reported in different series (2,6,16). Alotaibi et al. recommend admission in patients with signs of severity such as dyspnea, stridor, dysphagia, odynophagia, trismus, crepitus, and elevated white blood cell count (14). Specifically, a high C-reactive protein at admission has been associated with a more severe course of infection. It correlates with the length of hospital stay, the need for advanced airway management, more frequent ICU admissions, and complications (17,18 (15). Conversely, in our study, we observed a decrease in the number of patients admitted to the ICU, lower ICU length of stay, and mediasti-nitis in patients with dental extraction performed in the first three days of admission. Treviño et al. observed that a delayed time for dental extraction was associated with a length of hospital stay of >7 days (6). Regardless of the time of dental extraction, early management of ODNI with surgical drainage and intravenous antibiotic therapy is imperative. Specifically, gas formation identified in computed tomography has been associated with a higher complication rate, increased mortality, need for reintervention, and prolonged hospital and ICU stay (15). Reintervention rate among our population is 8%, which is associated with diabetes mellitus, the involvement of masticator and temporal space, and delayed dental extraction (6). With this in mind, expedited surgical and antibiotic management in these patients is crucial to avoid the infection extension, rates of complications and mortality, and the need for multiple surgical interventions.
Limitations of this study are mostly due to its retrospective design. Additionally, ICU stay and hemodynamical instability in patients with advanced ODNI could have delayed dental extraction. ODNI remain a common condition with potentially lifethreatening complications. Expedited management with surgical drainage and intravenous antibiotic treatment, along with the extraction of the involved tooth is mandatory. In our study, we observed a reduced number of surgical interventions, complications, and a decreased ICU length of stay in patients with early extraction of the dental infection focus. Larger, prospective studies are needed to support our findings.