Swallowing dysfunction after tracheostomy has been widely debated in the last two decades. Prior researches showed that tracheostomy tubes could impair swallowing causing an increased risk of aspiration through the following mechanisms: decrease in laryngeal elevation due to an anchoring effect of the tracheal tube [
2], desensitization of the larynx and loss of the protective reflex [
20], and uncoordinated laryngeal closure attributable to chronic upper airway bypass [
21]. On the contrary, recent investigations have come to the opposite conclusion [
4,
5]. Despite the high number of studies, most of them were methodologically not homogeneous, lacking of a standardized methods for the swallowing assessment. In this regard, our study suggests that a small-diameter and capped tracheal tube does not interfere with swallowing. Most of our cases 15/19 (78.9%) did not inhale, and the subjects 4/19 (21.05%) who aspirated during OPES with TT showed signs of aspiration also without TT and with the tracheal stoma directly occluded. However, the limitations of this study, including small sample size, do not allow to strongly affirm that aspiration is independent of tracheal tube; future studies are needed in this regard. We designed the study starting from few strong evidences. First of all, it is widely known that aspiration occurs more frequently when the tracheostomy tube is open [
22] due to the inability to increase subglottic pressure in this condition, which may be responsible for increased aspiration [
23]. Second, most authors agree that the presence of a cuff or the presence of a tracheal tube with inadequate diameter can cause dysphagia, suggesting that rehabilitation consequently involves the removal of the cuff and the progressive reduction in tracheal tube diameter [
24]. For these reasons, we assessed the effect of the tracheal tube in a closed respiratory system (
i.e., closed tracheal tube or closed tracheal stoma). Recent studies [
4,
5] did not standardize the sample based on the tracheal tube features (diameter and cuff), thus providing biased results. The effect of tracheal tube on swallowing was previously studied by means of videofluoroscopy (VFS) [
5] and FEES [
4,
6]. Even though VFS is still considered the gold standard, there are numerous reports in literature that emphasize the validity of OPES for the swallowing assessment [
12,
25]. In clinical practice, OPES is the only tool available to provide an exact percentage of the aspiration into the respiratory tract [
26] and an exact measurement of how long each of the three swallowing stages take, with detailed calculation of transit time and of any bolus retained in the oral cavity, pharynx or esophagus. The main limitation of this technique is the lack of well-defined morphological details of the structures involved [
27,
28]. However, the measurements of premature pharyngeal entry, pharyngeal transit time, and post-swallow pharyngeal stasis by scintigraphy are well correlated with those of VFS [
29]. In a recent study, Fattori B. et al. [
30] compared FEES, VFS, and OPES concluding that all three are capable of supplying an accurate diagnosis of oropharyngeal dysphagia and, more specifically that the detection of airway aspiration is recognized as the foremost advantage of scintigraphy. We selected OPES also because it is well tolerated by patients, and it could be repeated for treatment planning, rehabilitation, and follow-up of patients thanks to the lower dosage of radiation (0.043 Gy and 0.011 mSv/MBq) [
31]. On the other hand, the OPES technique forced us to exclude from the sample seriously impaired patients unable to suck through a straw or to maintain the erect position, which is another important limit of our work since the inclusion of more severe dysphagic patients may have increased the incidence of aspiration.
Our study aimed to clarify the real impact of tracheal tube on swallowing. In general, patients who underwent major head neck oncologic surgery start the rehabilitation within few days after surgery, and the tracheostomy and tracheal tube are undoubtedly conditions that could ensure better management of pulmonary secretions allowing access to remove aspirated material, therefore, reducing bronchopulmonary complications during the swallowing training. This is even more important for two reasons: first, because the duration of hospitalization has shortened over time, and for this reason, the swallowing rehabilitation is mainly carried out on an out-patient basis. Second, in the cases who require adjuvant radiotherapy, the maintenance of the tracheostomy is an indispensable safety condition.
In 2007, Coscarelli et al. [
33] described the results of a new swallowing rehabilitation protocol, specifically started two weeks after surgery without the tracheal tube, applied in 33 patients who underwent open partial horizontal laryngectomy (OPHL). The time for the complete recovery of oral intake and the incidence of pneumonia were the selected outcomes. They concluded that during rehabilitation exercises, the absence of tracheal tube improves swallowing by a better closure of the remaining larynx. Nevertheless, this study lacked the control group and did not provide objective data of the swallowing performances. Similarly to our results, Leder et al. [
34] investigated by means of VFS the effects of tracheal tube on aspiration status, interpreting the modified barium swallowing by repeated viewings of the videotapes in order to confirm the presence or absence of aspiration in patients with head and neck cancer after two weeks from the surgery, and they did not find any differences in aspiration status of patients with and without tracheal tube. Regarding the abnormal OPES data obtained from oral and pharyngeal phases’ analysis in our group, they seem to be related with the type of surgery that extensively involved oral and oropharyngeal sites, disrupting the dynamic of swallowing, without impacting significantly on the main goal of our study.
In conclusion, our overall results demonstrated the lack of statistically significant differences in each of the oropharyngoesophageal scintigraphy (OPES) parameters in the two conditions of the study, with and without the use of a small, closed tracheal tube, minimizing the impact of the tracheal tube on swallowing in head and neck cancer patients.