Tapio Pirilä

Incidence of Pituitary Adenomas in Northern Finland in 1992-2007

CONTEXT Data on the incidence of pituitary adenomas (PAs) are scant and outdated. A population-based regional cohort with thorough case identification was used to evaluate the incidence of clinically detected PAs in the era of magnetic resonance imaging. OBJECTIVE The objective of the study was to describe the age- and sex-specific incidence of all PA subgroups, with data on incidentally found PAs, pituitary apoplexies, and time trends. DESIGN, SETTINGS, AND PATIENTS This was a retrospective descriptive analysis of PA patients diagnosed during 1992-2007 in Northern Finland (NFi). MAIN OUTCOME MEASURE World Health Organization 2000-standardized incidence rates (SIRs) of PAs per 100,000 were measured. RESULTS AND CONCLUSION The final cohort consisted of 355 PAs. The incidence rates of the Oulu University Hospital regional district were used as a reference to assess the applicability of our case finding over the rest of NFi. Incidence rates of all PA subgroups except microprolactinomas were statistically equal between these areas; thus, all presented SIRs are based on the NFis cohort except Oulu University Hospital regional district-based prolactinomas and PAs overall. Overall SIR of PAs was higher (4.0 per 100,000) than in previous reports. Prolactinomas had the highest SIR: 2.2 per 100,000, followed by clinically nonfunctioning PAs (1.0) and GH-secreting (0.34), ACTH-secreting (0.17), and TSH-secreting (0.03) PAs. The gender-specific SIR was 2.2 per 100,000 in males and 5.9 per 100,000 in females. Pituitary apoplexy occurred as a presenting symptom in 11% of clinically nonfunctioning PA patients. The SIR of incidentally discovered PAs increased significantly from 1992-1999 to 2000-2007 (0.59 to 1.6, respectively; P < 0.01), which accounted for the perceived increasing trend in the overall SIR of PAs (3.8 to 4.2; P > 0.05).

Left-Right Asymmetries in Hearing Threshold Levels in Three Age Groups of a Random Population

The average asymmetry between the hearing threshold levels in the left and right ears was analyzed in a random population (n = 3487) representing a normal population. Males and females of age groups 5-10 years, 15-50 years and over 50 years were analyzed separately. A significant average inferiority of the hearing in the left ear was found at high frequencies, especially at 3-6 kHz, among adult males and females but not among children. A slight but statistically significant average superiority of the left ear at low frequencies was noted in all age groups. At corresponding hearing threshold levels at 4 kHz, the average inferiority of the left ear in the male population was significantly greater among subjects aged 15-50 years than among older subjects. In conclusion, the inferiority of hearing in the left ear at 4 kHz seems to be associated more with noise damage than with presbyacusis. The average interaural difference at 4 kHz was significantly more marked among subjects aged 15-50 years than among older subjects when analyzed at the corresponding threshold levels. These findings indicate a pathophysiological difference between noise damage and presbyacusis.

Hearing Asymmetry Among Left-Handed and Right-Handed Persons in a Random Population

The possible effect of handedness on hearing threshold asymmetry was analysed in a large random population representing a normal population. The left ear was on an average slightly but significantly poorer than the right ear at high frequencies, especially at 4 kHz, while at low frequencies the right ear was on average poorer than the left ear. A matched control group of the right-handed subjects was formed for 211 left-handed subjects. Among the left-handed subjects the average ear asymmetry resembled the ear asymmetry of the whole population, the right-handed subpopulation, and of the matched control group. In conclusion, it seems that handedness cannot be responsible for the average inferiority of hearing in the left ear at 4-kHz or for the average slight superiority of the left ear at 0.125-0.5 kHz. However, this analysis does not rule out possible minor effects of handedness on ear asymmetry.

HEARING ASYMMETRY. AMONG OCCUPATIONALLY NOISE EXPOSED MEN AND WOMEN UNDER 60 YEARS OF AGE

Interaural asymmetry of hearing thresholds at 4 kHz was analysed in four populations exposed to occupational noise. The left ear was found to be on average significantly worse than the right ear, among both the male and female subjects. In the male population the left ear was twice as often the worse ear as the right one. In the female population the corresponding ratio was 1.5. The average inferiority of the left ear increased as a function of the hearing threshold level. Among subjects with abundant shooting (reindeer herders) the average inferiority of the left ear was close to the average of all male subjects. Interaural difference increased as a function of the hearing threshold level, both among subjects with the left ear and subjects with the right ear being the worse one. In the male population the interaural difference was significantly greater in the former than in the latter group of subjects.

Left-right Asymmetry in the Human Response to Experimental Noise Exposure: I. Interaural Correlation of the Temporary Threshold Shift at 4 kHz Frequency

Most epidemiological surveys concerning populations exposed to occupational noise or random populations have shown that the left ear is slightly but significantly poorer than the right ear, especially at frequencies most susceptible to noise damage. To experimentally study the possible left-right asymmetry in response to noise exposure, 28 non-shooting healthy young adults were exposed binaurally to symmetrical broad-band noise for a maximum of 8 h. 4 kHz hearing thresholds of each individual were monitored alternately in the left and right ears during short interruptions in the exposure. Considerable efforts were made to exclude any external factors that might influence the left-right asymmetry. A significant positive correlation between the temporary threshold shifts (TTS) in the left and in the right ear was found. The average TTS was higher in the left than in the right ear, the difference between ears being statistically indicative.

Physiological fluctuations in nasal resistance may interfere with nasal monitoring in the nasal provocation test.

The physiological fluctuations in nasal flow and resistance in allergic subjects were studied by monitoring 12 subjects with perennial occupational allergic rhinitis with active anterior rhinomanometry (AAR) for 3 h at 15 min intervals. The subjects were then challenged bilaterally with the diluent solution for allergen extracts and the effect was monitored with AAR. In AAR. cellular rubber nose adapters were used. Many physiological fluctuations in nasal patency were observed. Reference intervals were calculated for the changes in flow and resistance at the gradient pressure of 150 pa. For example, a 100% increase in unilateral resistance was found to be significant at the risk level of 5-10% for the observation time of 30-60 min. The corresponding increase for bilateral resistance was close to 70%. Challenge with diluent solution had a negliglible effect on the resistance fluctuation, the reference intervals being close to those for baseline monitoring. In conclusion, rapid changes in nasal flow and resistance in allergic subjects were common, and caution is necessary when interpreting these changes as a positive nasal reaction in the nasal provocation test. In addition, the use of other objective parameters, such as the amount of nasal secretion is recommended.

Left-right Asymmetry in the Human Response to Experimental Noise Exposure: II. Pre-exposure Hearing Threshold and Temporary Threshold Shift at 4 kHz Frequency

The repeatedly noted average inferiority of the left ear (or superiority of the right ear) in epidemiological surveys at frequencies most susceptible to noise damage has not been experimentally confirmed. Twenty-eight non-shooting young adults were exposed binaurally to broad-band noise for a maximum of 8 h in strictly symmetrical laboratory conditions. The left and right hearing thresholds of each individual were monitored during short interruptions in the exposure. The average interaural hearing threshold difference became statistically significant during the exposure, the left ear being worse than right. The negative correlation found between the pre-exposure threshold level and the temporary threshold shift (TTS) was more marked in the left than in the right ear. In conclusion a hypothesis is presented: a good hearing threshold level in the right ear seems to be better protected from noise-induced temporary threshold shift than a good hearing threshold in the left ear.

Preoperative Virtual Endoscopy and Three-Dimensional Imaging of the Surface Landmarks of the Internal Carotid Arteries in Trans-sphenoidal Pituitary Surgery

In trans-sphenoidal pituitary adenoma surgery the sella turcica is opened between the internal carotid arteries. Three-dimensional image processing methods were applied in this study to avoid the risk of damaging the arteries during the opening of the anterior wall of the sella. By using graphical software it was possible to combine the anatomies of the carotid arteries and the sellar wall into one non-perspective three-dimensional image. With a perspective image (virtual endoscopy), the sphenoid sinus landmarks were presented as if looking through a nasoendoscope. This also facilitated preoperative planning but the non-perspective images, with the carotid arteries marked, were found to be the most useful and suitable for clinical routine. The pituitary tumor itself and its relations with the adjacent structures were best evaluated from magnetic resonance imaging scans but, for the opening of the sellar wall and in the three-dimensional orientation with endoscopy, three-dimensional computerized tomography imaging with the carotid arteries marked was found to be helpful.In trans-sphenoidal pituitary adenoma surgery the sella turcica is opened between the internal carotid arteries. Three-dimensional image processing methods were applied in this study to avoid the risk of damaging the arteries during the opening of the anterior wall of the sella. By using graphical software it was possible to combine the anatomies of the carotid arteries and the sellar wall into one non-perspective three-dimensional image. With a perspective image (virtual endoscopy), the sphenoid sinus landmarks were presented as if looking through a nasoendoscope. This also facilitated preoperative planning but the non-perspective images, with the carotid arteries marked, were found to be the most useful and suitable for clinical routine. The pituitary tumor itself and its relations with the adjacent structures were best evaluated from magnetic resonance imaging scans but, for the opening of the sellar wall and in the three-dimensional orientation with endoscopy, three-dimensional computerized tomography imaging with the carotid arteries marked was found to be helpful.

Long-Term Health-Related Quality of Life of Surgically Treated Pituitary Adenoma Patients: A Descriptive Study

Context. The literature concerning the health-related quality of life (HRQoL) of patients with surgically treated PA is controversial. Objective. To describe the long-term HRQoL of surgically treated patients in all PA classes. Design and subjects. The 15D, a generic HRQoL instrument producing a 15-dimensional profile and a single 15D index score (a difference ≥0.03 on a 0-1 scale is considered clinically important), was used to assess the HRQoL of a 13-year surgical cohort of PA patients in Northern Finland. Results and Conclusion. Nighty-eight eligible consecutive patients with surgically treated PA were studied at an average of 6.3 years after their latest pituitary operation. The average postoperative 15D profiles in patients with non-functioning PA and in acromegalics without GH-suppressive medical treatment were similar to those of the age-standardized general population. However, after this rather long followup, the mean 15D score and the number of statistically significant 15D dimension impairments, compared with those of their reference population, were 0.11 and 9/15, 0.10 and 3/15, and 0.08 and 7/15 for Cushings disease, acromegalics needing somatostatin analog, and prolactinoma patients, respectively. Hypopituitarism with replacement medication was not associated with impaired HRQoL. The somatostatin-analog-associated HRQoL finding warrants further clinical research.

Ear protection against water-borne infection: an objective evaluation

Eight different ear plug materials were tested, in 5 ears each, in artificial shallow underwater conditions for 30 minutes, in order to determine their efficacy in sealing the ear canals to avoid water-borne infections in ear canals and open middle ears. Most of the plugs tested would meet everyday requirements for protection, but the polymeric foam plugs, treated with petroleum jelly, and moldable plastic materials were most effective in protecting both the middle ear and the ear canal skin.