Reduced olfactory bulb volume in total laryngectomy patients: a magnetic resonance imaging study

Abstract

Objectives: The olfactory bulb (OB) is a remarkably plastic structure with highly active afferent neurons, which is partly reflected by its volume. Although deterioration of olfaction after total laryngectomy is reported by many patients, this problem has not received widespread attention. There has been no study that had addresses this loss olfactory ability as a function of OB volume. The aim of this study was to determine OB volume changes after laryngectomy. Study design: Twenty one patients post-total laryngectomy and 17 subjects with normal olfactory function underwent magnetic resonance imaging (MRI) for volumetric measurement of the OB. The history of all participants was taken in detail to exclude other possible causes of smell dysfunction. Volumetric measurement of the OB was performed by manual segmentation of the OB into coronal slices. Olfactory function was assessed with the orthonasal olfaction test. Results: There was no statistically significant difference in volume between the right and left sides of the OB in the study and control groups. However, the study group had smaller OB volumes than the control group. In our assessment of orthonasal olfaction, patients who were post-total laryngectomy had worse orthonasal olfactory function than the control group. There were significant correlations between OB volumes and orthonasal test scores. Conclusions: Our MRI study showed that post-total laryngectomy patients had higher rates of olfactory bulb atrophy than the control subjects. Laryngectomy is associated with measurable decreases in olfactory function and this study hopes to further clarify this association by demonstrating that patients with total laryngectomy have reduced OB volumes when compared to the normal population.

Ipsilateral Reduced Olfactory Bulb Volume in Patients with Unilateral Nasal Obstruction

“…15 Many researchers have discussed the effect of various bilateral and systemic diseases on the size of OB. [3][4][5][6][7][8][16][17][18][19] These cross-sectional studies indicate that: (1) OBV seems to change in parallel to smell function, (2) OBV decreases with duration of olfactory loss, and (3) patients with parosmia present with smaller OB compared with those without. The effect of treatment on OBV was investigated by Gudziol et al, 20 who found that treatment of patients with chronic rhinosinusitis is accompanied by increased OBV.…”

Olfactory rehabilitation and olfactory bulb volume changes in patients after total laryngectomy: a prospective randomized study

“…Due to tracheostomy performed after total laryngectomy, the nasal airway is interrupted, and the neuroepithelium specialized for olfaction is deprived of odor particles. 6 Two mechanisms potentially explaining olfactory loss after laryngectomy are interruption of nasal airflow after laryngectomy and impairment of neurosensory feedback mechanisms after multiple peripheral nerve injuries during surgery. 5 The OB displays plasticity throughout adult life, based on two major neurobiological mechanisms; one is related to the continuity of neurogenesis from the subventricular zone, and the other is related to the continuity of synaptogenesis.…”

“… 1 OB volumes measured postoperatively in laryngectomized patients were reported to be lower than those in a similar age control group. 5 , 6 Atrophy of the olfactory neuroepithelium or the OB may play a role in the emergence of olfactory problems in patients after laryngectomy. 6 , 18 , 19 , 21…”

“… 5 , 6 Atrophy of the olfactory neuroepithelium or the OB may play a role in the emergence of olfactory problems in patients after laryngectomy. 6 , 18 , 19 , 21…”

“…7 , 8 , 9 Veyseller et al demonstrated in both cross-sectional and longitudinal studies that olfactory dysfunction and OB volume shrinkage occur in laryngectomy patients. 5 , 6 …”