Rehabilitation of the olfactory sense after laryngectomy: long-term use of the larynx bypass.

Abstract

Patients who undergo laryngectomy typically lose their sense of smell. One device that has been used to rehabilitate olfactory function in these patients is the larynx bypass. We conducted a long-term study of the larynx bypass in 16 laryngectomized patients. After undergoing objective and subjective baseline evaluations, patients were asked to use the device at home for at least 30 minutes each day for 3 months. They were also asked to record in a diary subjective ratings of their sense of smell and the practicability o fusing the device every day. At study's end, patients experienced a statistically significant improvement (p < 0.001) in olfactory function on objective measurement (Sniffin' Sticks testing). Subjective improvement was seen after 1 week (p < 0.001) and maintained throughout the study. Practicability scores improved statistically (p = 0.003), but the device remained difficult to use. The long-term use of the larynx bypass has not been studied previously, and we hope that our findings will serve as a basis for further investigation.

Introduction

A laryngectomy causes patients to lose not only their natural speech but also their sense of smell. The loss of olfactory sensation occurs because air intake through the nasal passages is no longer possible postoperatively; instead, air circulates exclusively through the tracheostoma. (1,2) Although the reduction in olfactory function does not receive as much attention as the loss of speech, it does diminish the quality of life of those affected. (3) Fortunately, laryngectomized patients can regain some olfactory function with the use of the larynx bypass device (figure 1). This device allows air to circulate through the nasal passages and thus stimulates olfactory receptors.

We previously studied the use of the larynx bypass in a single application, (4) and the promising results of that investigation served as the basis for this longer-term study (3 mo) to examine olfactory function and the practicability of the larynx bypass. Such a long-term investigation has not been previously described in the literature.

Patients and methods

Our study population was made up of 16 laryngectomized patients--14 men and 2 women (median age: 62 yr; semi-interquartile range: 52.5 to 65.5)--who had undergone laryngectomy between 1995 and 2003. (The semi-interquartile range [SIR] spans one half the difference between the 75th and 25th percentiles.) Fifteen of these patients had received adjuvant postoperative radiotherapy. At the time of the study, no patient had experienced a tumor recurrence or distant metastasis. Nine patients used a voice prosthesis.

Each patient participated in the study for a period of 3 months between Dec. 1, 2004, and April 30, 2005. At baseline, olfaction was rated both objectively and subjectively; patients also rated the practicability of using the larynx bypass subjectively.

The objective baseline test was performed at our Olfactory Consulting Service with Sniffin' Sticks, which are used to screen for olfactory disorders in German-speaking countries. (5-7) Sniffin' Sticks test kits are made up of 16 pen-like devices, each of which dispenses a different common odor. Patients smell each stick and then attempt to identify the scent from among four choices verbalized by an investigator (forced-choice method). Our patients smelled each of the 16 odors with and without using a larynx bypass device (Servox AG; Troisdorf, Germany). Each correct identification was worth 1 point. Generally, patients older than 50 years (as were all of our patients) can be classified thusly on the basis of their Sniffin' Sticks score: 0 to 8 points, anosmia; 9 to 11, hyposmia; 12 to 16, normosmia. (7) Patients were also asked to subjectively rate their sense of smell and the practicability of using the larynx bypass on a scale of 1 (very poor) to 10 (very good).

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Patients were then given thorough instruction on the home use of the larynx bypass and asked to use the device for at least 30 minutes once a day for 3 months. They were asked to use the same 10-point scale to subjectively rate their sense of smell and the practicability of using the device and to record their ratings in a daily diary. (In addition to baseline and end-of-study comparisons, changes in subjective olfaction were also compared at 1 and 3 weeks for the purposes of this analysis.) At study's end, patients returned to the Olfactory Consulting Service to submit their diaries and to undergo final evaluation, including a follow-up Sniffin' Sticks test.

For statistical analysis, we used the nonparametric Wilcoxon test for dependent data because the distribution of data was not normal. Differences between the sexes were not tested because of the small number of women (n = 2).

Results

Objectiveolfaction scores. At baseline, the median score on the 16-point Sniffin' Sticks test without the larynx bypass was 3 points (SIR: 3 to 4) (figure 2). The overall range of scores was 0 to 5, indicating that all patients were in the anosmia category. With the use of the larynx bypass, the baseline median score rose to 7 points (SIR: 6 to 8)--a statistically significant difference (p < 0.001). With the larynx bypass, 5 patients reached a baseline score of 8 points, which is the upper threshold of the anosmia category, and 2 others achieved even higher scores, moving from the anosmia category to the hyposmia category. One patient achieved the same score with and without the larynx bypass, 2 patients improved by 1 or 2 points, 11 patients improved by 3 or 4 points, and 2 patients improved by 5 or 6 points.

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At the 3-month evaluation, median Sniffin' Sticks scores were 4 points (SIR: 2.5 to 5) without the larynx bypass and 8 points (SIR: 7 to 9) with it--again, a statistically significant difference (p < 0.001). Without the bypass, all patients scored between 0 and 6 (anosmia). With the bypass, 6 patients scored 9 or 10 points (hyposmia), and 1 patient reached 13 points (normosmia). No patient achieved the same score with the larynx bypass, 2 improved by 1 or 2 points, 9 improved by 3 or 4 points, 4 improved by 5 or 6 points, and 1 patient improved by 13 points.

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No patient had a lower score with the bypass, either at baseline or at 3 months.

Subjective olfaction scores. At baseline, the median subjective olfaction score on the 10-point scale was 4 (figure 3). One week later, the median score had risen to 5--a statistically significant improvement (p < 0.001). This improvement was maintained (although not increased) throughout the remainder of the study.

Subjective practicability scores. At baseline, the median practicability score on the 10-point scale was 5 (SIR: 4.25 to 5) (figure 4). At study's end, the median score had risen to 5.5 (SIR: 5 to 6)--a statistically significant (p = 0.003) but not clinically significant difference.

Discussion

In addition to the larynx bypass, another method of olfactory rehabilitation described in the literature is "polite yawning." (8) This maneuver involves inhaling through the nose with the teeth apart but the lips closed.

Detailed information on the larynx bypass is lacking in the literature. In our previous study of a single application of the larynx bypass, which was conducted in 2004 and published in 2005, we found that use of the device significantly improved olfaction. (4) However, patients said it was very difficult to manage and was not suited for everyday use. Still, the results of that study were encouraging enough to prompt this longer-term investigation. While the improvements in olfaction in the present study were statistically significant, the larynx bypass still failed to gain patient acceptance for use as a daily therapy, even though patients apparently got used to using the device over the 3-month period. No patient experienced any complications or adverse events such as dyspnea, allergy, or bleeding.

In conclusion, the results of the present study confirmed our preliminary findings (4) in that the larynx bypass significantly improves the sense of smell in tracheotomized patients in the short term. We also found that this improvement extended to the long term as well. Yet despite the improvements seen with everyday use, practicability remains problematic. It remains to be seen whether technical improvements can increase the level of patient acceptability. Further studies are required.

References

(1.) Henkin RI, Hoye RC, Ketcham AS, Gould WJ. Hyposmia following laryngectomy. Lancet 1968;2(7566):479-81.

(2.) Mozell MM, Schwartz DN, Youngentob SL, et al. Reversal of hyposmia in laryngectomized patients. Chem Senses 1986;11(3):397-410.

(3.) Sewnaik A, van den Brink JL, Wieringa MH, et al. Surgery for recurrent laryngeal carcinoma after radiotherapy: Partial laryngectomy or total laryngectomy for a better quality of life? Otolaryngol Head Neck Surg 2005;132(1):95-8.

(4.) Goktas O, Lammert I, Berl, J, Schrom T. Rehabilitation of the olfactory sense after laryngectomy--the larynx bypass [in German]. Laryngorhinootologie 2005;84(11):829-32.

(5.) Hummel T, Sekinger B, Wolf SR, et al. Sniffin' Sticks: Olfactory performance assessed by the combined testing of odor identification, odor discrimination and olfactory threshold. Chem Senses 1997;22(1):39-52.

(6.) Kobal G, Hummel T, Sekinger B, et al. "Sniffin' Sticks": Screening of olfactory performance. Rhinology 1996;34(4):222-6.

(7.) Kobal G, Klimek L, Wolfensberger M, et al. Multicenter investigation of 1,036 subjects using a standardized method for the assessment of olfactory function combining tests of odor identification, odor discrimination, and olfactory thresholds. Eur Arch Otorhinolaryngol 2000;257(4):205-11.

(8.) Gudziol H, Beleites E. Riechvermogen nach Laryngektomie. Wissenschaftliche Zeitschrift der Humboldt-Universitat zu Berlin 1991; 40:43-4.

Onder Goktas, MD; Franca Fleiner, MD; Christian Paschen, MD; Ingeborg Lammert, MD; Thomas Schrom, MD

From the ENT Department, Charite University of Medicine, Berlin, Germany.

Corresponding author: Onder Goktas, MD, ENT Department, Charite Campus Mitte, Universitatsmedizin Berlin, Chariteplatz 1,10117 Berlin, Germany. Phone: [phone]; fax: [phone]; e-mail: [e-mail]

Financial disclosure: The authors have no financial interest in the products or businesses mentioned in this article.