Discussion
Our study confirmed that a relevant proportion of patients with thyroid disease, if carefully enquired with a standardized instrument, complains of globus pattern symptoms of moderate or strong severity (57.8%). A second group declares mild symptoms (21.1%) and only about 20% of patients are completely asymptomatic or just report faint feelings in the domain of globus. When the mean GETS score was considered, a significant decrease of the severity of symptoms was observed after thyroidectomy, but this decrease was mainly due to the improvement of strongly symptomatic patients (Table 3). When the change of the pre-postoperative GETS score of each patient was considered (Table 4), a group of patients appeared who were asymptomatic or mildly symptomatic at the preoperative assessment and whose severity of symptoms increased in the postoperative period (12/95 patients = 12.6%). Another larger group of patients (26/95 patients = 27.4%) were mildly o definitely symptomatic and maintained unchanged their symptoms while the largest group of symptomatic patients improved (37/95 patients = 38.9%). These data indicate that surgery improves the condition of patients with moderate or intense globus pattern symptoms, but may make symptoms appear in asymptomatic of weakly symptomatic patients.
These findings suggest that the pathophysiology of globus pattern symptoms may be different: in some cases connected with thyroid disease, in other cases with the effect of surgery itself. Finally, in some patients of this series, globus pattern symptoms remained unchanged and seemed to be independent both from thyroid disease and from thyroidectomy. An alternative interpretation for the group of patients who remained symptomatic is that thyroidectomy produced the same pathophysiological effect as the presence of an ill thyroid did before the operation.
Other studies enquired the relationship between thyroid surgery and globus pattern symptoms, but all of them had limits either in the representation of data or in the extent and method used to assess globus pattern symptoms. In a small scale study, Maung et al. did not find any significant worsening of GETS score three and twelve months after surgery. Some of the items of the GETS showed instead an improvement. Unfortunately the authors did not provide the mean total GETS score nor the mean values for each item, so a comparison with our study is not possible. Burns et al. [ 14 ] in a series of 200 patients who underwent thyroidectomy found 58 patients (29%) with preoperative globus symptoms, which reduced to 12 (6%) 3–6 months after the operation. The authors used a visual-analogue scale graduated from 1 to 10 to let the patient self-assess the globus sensation as a whole. Wasserman et al. reported instead an increase of globus sensation, from 57.6% to 75.8% of patients one week after thyroid surgery. The focus of their study was on the correlation of symptoms with the function of the internal branch of the superior laryngeal nerve (SLN), which brings sensitivity to the larynx, but they could not find any significant decrease in SLN functioning. Lombardi et al. reported an increase in swallowing alterations after thyroidectomy. They measured the symptoms with an original questionnaire, reporting a very low preoperative score, a strong rise one week after surgery and a progressive decrease after one and three months. Unfortunately they questionnaire fully covered only the dimension of dysphagia and partly the dimension of globus sensation of the GETS. In a wide Italian multicentric study on postoperative complications in 14,943 operations on thyroid, dysphagia was the only symptom considered in the globus pattern domain and only in relation to SLN damage. Finally, Smith-Hammond et al. reported a significant increase of dysphagia – measured with a standardized questionnaire – after spine surgery with anterior cervical approach, accessing the same anatomical space as in thyroid surgery.
The terms in which the globus symptoms are described by patients vary largely and this is why we preferably referred to a pattern of globus symptoms. To manage this variability, it is important to rely on a validated and comprehensive instrument like the GETS. The Italian version of the GETS we used had a good reliability and the same factorial structure as the original one. Normative data on the general and ENT population are available and indicate that a significant proportion of people without any evident structural pathology has a score of 1 or 2 at one of the items of the GETS (up to 55.2% for "Catarrh down throat" in). The four classes of score we proposed are coherent with the above mentioned normative data and are clinically oriented. The classification of patients allowed to uncover three different dynamics, which were otherwise obscured by the synthetic presentation of data only by the pre and postoperative means: symptomatic patients who improved their symptoms after surgery, asymptomatic patients who developed symptoms after surgery and patients whose symptoms seemed not to be influenced by surgery.
The main limit of this study is the short follow up interval, limited to three months. It is known that symptoms tend to resolve after one year. Nevertheless, even if symptoms are temporary, it is important to know their frequency in order to make patients informed and aware. Another possible limitation is that each interview was made only by one of the two trained observers, even if they had reached a good inter-rater agreement during the testing phase. We did not assess in any formal way the presence of gastro-esophageal reflux apart from history taking, so we cannot exclude that some of the patients who remained symptomatic could have been suffering from an unknown reflux. We did not correlate symptoms with smoking habit or with other possible risk factors for globus pattern symptoms, such as thyroid volume, since the goal of this study was to measure frequency and severity of pre e and postoperative symptoms in a population of patients operated for thyroid disease.
As a last remark, it is known that a repetitive strain injury of the paralaryngeal muscles can cause globus-like symptoms. This mechanism could be considered either in the event of preoperative or postoperative symptoms. In these cases, manual therapy proved to be effective in quickly relieving the symptoms.