A placebo-controlled study of inferior turbinate surgery

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Arvo building, auditorium F114, address: Arvo Ylpön katu 34.

Doctoral defence of Lic.Med. Teemu Harju

A placebo-controlled study of inferior turbinate surgery

The field of science of the dissertation is Otorhinolaryngology.

The opponent is docent Juha Seppä (University of Eastern Finland). Professor Markus Rautiainen acts as the custos.

The language of the dissertation defence is Finnish.

A placebo-controlled study of surgical treatment of chronic nasal obstruction

Chronic nasal obstruction is a common symptom that has many adverse effects. Chronic nasal obstruction has several different anatomic and physiologic causes, such as allergic and non-allergic rhinitis, chronic rhinosinusitis, anatomic abnormalities and hormonal disorders  

On both sides of the nose there are three turbinates that extend the length of the nasal cavitys. Turbinates are bony structures that are covered with submucosal tissue and respiratory mucosa and they have an important role in the normal function of the nose. Inferior turbinate is the biggest of the turbinates and the swelling and shrinking of its submucosal venous tissue has a great role in the regulation of nasal patency. In inferior turbinate enlargement long standing swelling due to allergic or non-allergic rhinitis becomes irreversible and medical treatment with nasal corticosteroids fails. In that kind of cases inferior turbinate surgery can be considered.

Various surgical techniques have been described for the reduction of enlarged inferior turbinates. Only three of the previous studies of inferior turbinate surgery have been placebo-controlled and, based on them, the placebo effect seems have a role in the results of the surgery. The relationship between Eustachian tube dysfunction and inferior turbinate enlargement or inferior turbinate surgery has never been studied before. Furthermore, most of the studies that have evaluated the effect of inferior turbinate surgery on ciliated epithelium have only been descriptive and lacked statistical analysis.

In the present study, the patients were blinded and randomized into placebo, radiofrequency ablation (RFA), diode laser or microdebrider-assisted turbinoplasty (MAIT) groups in a ratio of 1:2:2:2. A total of 98 patients underwent one of the four alternative procedures. All the patients were evaluated prior to operation and three months subsequent to the operation. All the procedures, including placebo, decreased the symptom score of severity of nasal obstruction significantly. However, all three active treatments decreased the symptom score of severity of nasal obstruction significantly more than the placebo procedure.

The relationship between inferior turbinate enlargement and Eustachian tube dysfunction related ear symptoms was evaluated using an Eustachian tube dysfunction questionnaire as an assessment method. The symptom score was found to be significantly higher in the inferior turbinate enlargement group.

The effect of inferior turbinate surgery techniques on Eustachian tube dysfunction related ear symptoms was evaluated with the same questionnaire. All the active treatments decreased the ear symptoms significantly, but there were no significant differences in the results between the placebo procedure and active treatments.

The effect of three surgical techniques on ciliated epithelium was evaluated comparing pre- and postoperative mucosal biopsies that were examined with scanning electron microcopy. The number of cilia was found to increase significantly after RFA and MAIT treatments and the amount of squamous metaplasia increased significantly after diode laser treatment.

From the above-mentioned findings, we conclude that 1) the placebo effect has a large role in the overall reduction in the severity of nasal obstruction in inferior turbinate surgery. However, all three examined techniques provide a statistically significant additional reduction in the severity of nasal obstruction compared with the placebo procedure. 2) Patients with inferior turbinate enlargement have more symptoms related to Eustachian tube dysfunction than healthy controls. 3) The improvement of Eustachian tube dysfunction related symptoms due to inferior turbinate surgery as a sole procedure is equal to placebo. 4) RFA and MAIT are more mucosal preserving techniques than diode laser.

The dissertation is published in the publication series of Acta Universitatis Tamperensis; 2415, Tampere University Press, Tampere 2018. The dissertation is also published in the e-series Acta Electronica Universitatis Tamperensis; 1925, Tampere University Press 2018.

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