ORIGINAL ARTICLE Long-term Follow-up of Surgically Treated Phantosmia Donald A. Leopold, MD; Todd A. Loehrl, MD; James E. Schwob, MD, PhD Objectives: To determine whether transnasal excision Results: Of 8 patients, 7 have complete and permanent of olfactory epithelium is a safe, effective therapy and to resolution of their phantosmia. Postoperatively, the learn more of the pathogenesis of phantosmia by study- single nostril olfactory ability in the operated-on nostril ing the histological features of the excised mucosa. is decreased in 2 nostrils, remains unchanged in 7, and is improved in 1. The excised olfactory mucosa gener- Design: A retrospective study consisting of a medical re- ally shows a decreased number of neurons, a greater ra- cord review and telephone survey. Follow-up ranged from tio of immature to mature neurons, and disordered 1 to 11 years (average, 5.4 years). Excised tissues were his- growth of axons with some intraepithelial neuromas. tologically processed and descriptively compared with nor- mal and other abnormal olfactory tissues. Conclusions: Surgical excision of olfactory epithelium Setting: Tertiary university medical referral centers. is an effective and safe method to relieve phantosmia while Patients: All patients who presented to the primary au- potentially preserving olfactory ability. The abnormal his- thor (D.A.L.) from 1988 to 1999 with unremitting phan- tological features of the excised olfactory tissue suggest tosmia lasting longer than 4 years. at least some pathological condition in the peripheral ol- factory system. This nasal surgery requires intensive ol- Intervention: Olfactory testing and transnasal endo- factory evaluation and follow-up. It is also extremely dif- scopic excision of olfactory mucosa. ficult with significant risks, and therefore should be limited to specialized centers. Main Outcome Measures: Tested olfactory func- tion, patients’ perception of phantom odor resolution, and histological findings. Arch Otolaryngol Head Neck Surg. 2002;128:642-647 HANTOSMIA IS the intermit- onset of the phantosmia. When the phan- tent or continuous percep- tom perception is present, everything the tion of an odor when no patient eats has this flavor, and foods do odorant stimulus is present. not mask the perception. All of these pa- Some individuals with this tients with phantosmia have a self- Psymptom perceive the odor independent admitted poor quality of life, with each of nasal airflow, and there is no change in meal having the aroma of foul meat, the odor perception when nasal airflow is burned garbage, or feces. It is usual for the blocked unilaterally or bilaterally. There patients to have thought about suicide be- From the Departments of are other individuals, however, in whom cause they had been offered no hope for Otolaryngology–Head and blockage of uninasal airflow eliminates the resolution from other physicians. Neck Surgery, University of phantom odor, and they are the subject of The perceived odor usually lasts only Nebraska Medical Center, the present article. Most commonly, the a few minutes the first time it is experi- Nebraska Medical Center, perceived odor is unpleasant, and is typi- enced, and it almost always has a sponta- Omaha (Dr Leopold), cally described as “burned,” “foul,” “rot- neous onset. It then will recur at monthly, Otolaryngology–Head and ten,” “sewage,” or “chemically.” A vari- then weekly, then daily intervals over a pe- Neck Surgery, Medical College of Wisconsin, Milwaukee ety of extrinsic or intrinsic stimuli such as riod of 6 months to a year. The duration (Dr Loehrl), and Anatomy changes in nasal airflow, strong odor- that the perceived odor is present also in- & Cellular Biology, Tufts ants, or loud sounds can trigger the odor creases over the same time, often lasting University School of Medicine, or it may appear spontaneously. Some pa- most of the day after 1 year. For the first Boston, Mass (Dr Schwob). tients may have an aura associated with the year or two, the phantom smell sponta- (REPRINTED) ARCH OTOLARYNGOL HEAD NECK SURG/ VOL 128, JUNE 2002 WWW.ARCHOTO.COM 642 ©2002 American Medical Association. All rights reserved. Downloaded From: https://jamanetwork.com/ on 10/01/2021 PATIENTS AND METHODS perceived olfactory function, and whether they would have the surgery if they had it to do over again. The length of follow-up ranged from 1 to 11 years (average, 5.4 years). PATIENTS A meaningful change in olfactory function was defined as a change of greater than 5 odorants on the SIT. Eight patients (7 women and 1 man) presenting to the pri- mary author (D.A.L.) from August 1988 to May 1999 with SURGICAL TECHNIQUE phantosmia lasting longer than 4 years were reviewed. The length of symptoms ranged from 4 to 19 years (average, The surgery was performed under general anesthesia us- 8.2 years). Preoperative evaluation included a thorough ing transnasal and transethmoidal endoscopic techniques history, a complete head and neck examination, nasal on only 1 side and was generally the same in each patient. endoscopy, uninasal smell testing (eg, a 40-odorant The olfactory mucosa was removed along the length of the scratch-and-sniff Smell Identification Test (SIT) [Senson- cribriform plate, taking care to sharply cut the fila olfac- ics Inc, Haddonfield, NJ]), and computed tomography of toria as they were identified. The area was then inspected the sinuses as well as magnetic resonance imaging or com- for cerebrospinal fluid leak. A mucoperiosteal graft was puted tomography scan of the head to rule out intracranial placed against the cribriform plate to prevent cerebrospi- pathological conditions. All these patients were judged to nal fluid rhinorrhea and treat it when it occurred. The pa- be psychiatrically stable in that they were all employed, tients remained in the hospital overnight on bed rest with displayed no unusual behavior, did not have histories of the head of the bed elevated. All excised olfactory mucosa alcohol or drug abuse, displayed a lively affect, and had was sent for special immunostaining. The surgery that was logical thought patterns. None of the patients thought the done in those patients who failed to improve the first time odors were coming from them, or referred to the odor as was performed in a similar manner. This operation is dif- being human in origin. Most importantly, blocking the ficult because the olfactory nerve tissue is tough in char- involved nostril could always stop the perceived odor. acter and difficult to cut sharply because of the angles in- All patients underwent a sequential uninasal anesthe- volved. Care is also needed to operate “gently” to avoid tization of each olfactory cleft, which temporarily elimi- disturbing the neural tissue of the olfactory bulb, and the nated the phantom odor when the involved nostril was se- orbital tissues that are close. Finally, the operation must lected. This was performed by dripping 1 cm3 of 4% cocaine be done with attention to preserving ventilation, stability, into the patient’s nostril while their neck was fully ex- and mucosal coverage of all nasal and ethmoid tissues. tended and they were supine. The level of anesthesia could be judged by the lack of response to olfactory stimuli. Elec- HISTOLOGICAL METHODS troencephalograms had been obtained on 3 patients to de- termine if there was any abnormal brain electrical activity. Excised tissue was fixed by immersion in Bouin fluid for 2 Positron emission tomography of the brain using fluoro- to 4 hours and embedded in paraffin. Serial sections were deoxyglucose is an imaging technique that was performed collected throughout the entirety of the tissue, and se- in 3 patients to help understand the disease and to possi- lected ones were immunostained with antibodies against bly aid in their care. olfactory marker protein (anti-OMP) (the gift of Frank Mar- Follow-up data were obtained through medical rec- golis, PhD, University of Maryland, Baltimore), neurotu- ord review and telephone interviews. Also, a SIT was bulin (antineurotubulin [anti-NT] monoclonal anti- mailed to each patient with instructions to perform uni- body), and growth-associated protein GAP-43 (monoclonal nasal smell testing. The telephone interview included antibody 7B10) (the gift of Karina Meiri, PhD, Upstate Medi- questions regarding nasal and sinus status since surgery, cal University, Syracuse, NY) using standard techniques.5,6 neously resolves with more than an hour of sleep. Pa- cluded sedatives and antiepileptic drugs.1 Patients re- tients often describe stereotypical methods to relieve the ceiving these treatments may not experience relief, or the unpleasant odor perception, including bending over and adverse effects may limit their use. Surgical treatment has holding the ankles while holding the breath, forced cry- included olfactory bulb ablation through a bifrontal cra- ing, intranasal instrumentation, and gagging. All of these niotomy approach.2,3 This procedure results in bilateral manipulations, including sleep, eventually fail to re- permanent anosmia and includes the risks associated with solve the phantosmia. a craniotomy. Many of the patients stated that their olfactory abil- Although the pathophysiological mechanisms of ity fluctuated, with it being worse when the phantom odor phantosmia are poorly understood, there is some evi- perception was present. Olfactory testing usually reveals dence to suggest that it is either a peripheral problem in a decreased olfactory ability in the involved nostril. the olfactory mucosa or axons or a central phenomenon Because phantosmia is a rare and poorly under- with a peripheral stimulus.4 Thus, resection of the olfac- stood disorder, there has been no well-defined treat- tory mucosa could possibly eliminate the phantom odor ment. Often, patients are given ineffective therapy, and by eliminating the peripheral disease or input. Previous numerous providers will instruct them to “just live with experience with a single patient has suggested that trans- it.” Because of analogies with psychiatric conditions, some nasal endoscopic excision of olfactory epithelium can suc- patients are told that they have a mental illness.