Measurement of human testicular consistency by tonometry*

Transcription

1 Vol. F'ERTUTY AND STERLTY Copyright c 1985 The American Fertility Society, No. 6, June 1985 Printed in U.S A. Measurement of human testicular consistency by tonometry* Ernest L. Lewis, M.D.t Marianne 0. Rasor, M.A.:f: James W. Overstreet, M. D., Ph.D.:f: University of California, Davis, School of Medicine, Davis, California A tonometer was used for objective assessment of testicular consistency in a group of 8 men. Testicular measurements in three dimensions were also obtained using calipers. The testicular tonometry value was found to be significantly correlated with the clinical impression of testicular consistency and with testicular size. The testicular tonometry value for the right testicle was significantly larger than the tonometry value for the left testicle in all men except those with azoospermia. The difference in tonometry values between the right and left testicles was most significant in the group of men with left varicocele. The men with varicoceles also had left testicles which were significantly smaller than the paired right testicle in two of three dimensions. n the group with varicocele there was a significant positive correlation between the tonometry value and sperm concentration in the semen. n men with no history of varicocele there was a significant positive correlation between the tonometry value and the percentage of oval sperm. Fertil Steril :91 1, Clinical evaluation of testicular size and con sistency traditionally has been considered impor tant in the physical examination of the subfertile man. Hotchkiss, in his book Fertility in Men, pub lished in 19, 1 pointed to the importance of tes ticular palpation in the physical examination and stressed the coincidence of small, soft testicles with infertility. This association has been subse quently reaffirmed, and the use of calipers for testicular measurement has replaced the practice of subjective size assessment in many clinics. Received October 9, 198; revised and accepted February 1, *Supported by National nstitutes of Health grant HD and National nstitute for Occupational Safety and Health grant OH tdepartment of Urology. :J:Department of Obstetrics and Gynecology. Reprint requests: James W. Overstreet, M. D., Ph.D., Di vision of Reproductive Biology and Medicine, University of California, Davis, California Vol., N o. 6, June 1985 Lipshultz and Corriere:.! utilized calipers to mea sure testicular size in normal volunteers and in infertility patients with and without palpable varicoceles. They found that the left testicle was significantly smaller than the right testicle in men with varicocele, including volunteers who had previously unsuspected varicoceles. They fur ther reported a significant diminution in the size of both testicles in subfertile men with varicoceles as compared with subfertile men who did not have a varicocele. There have been no similar attempts to objec tively measure the consistency of human testicles in health or disease. A possible approach to ob taining such information has been published in the vet rinary literature. To evaluate the consis tency of the bovine testes, a tonometer was devel oped which produced face deflection measure ments when applied to the scrotal skin stretched across the testicle. A high degree of repeatability was demonstrated with the instrument, and a cor relation of tonometry readings with manual pallewis et al. Human testicular tonometry 911

2 Figure 1 The probe of the tonometer measures testicular consistency through the skin of the scrotum. pation and some parameters of semen quality was reported. n this communication, we report our initial experience with the application of a tonom eter for assessment of human testicular consis tency. MATERALS AND MEmODS SUBJECTS A total of 8 men was studied. Twenty-eight men were workers being screened in our occupa tional health clinic for routine surveillance of possible reproductive hazards. Six of these men were azoospermic, presumably as a result of pre vious exposure to dibromochloropropane. None of the remaining men in this group had clinical infertility, although some had abnormal semen by clinical criteria.5 Fifty-five of the men in the study population were patients referred to our infertility clinic for urologic evaluation because of an infertile marriage. Two of these men were azoospermic, some had normal semen quality, and others had varying degrees of oligospermia. PHYSCAL EXAMNATON All physical examinations were performed by a single observer (E. L. L.). After a general medical history and physical examination, a clinical eval uation of the genitalia was performed. The exter nal genitalia were examined, and the testicles 91 Lewis et al. Human testicular tonometry were assessed subjectively for size (small, normal, large) and for consistency (soft, normal, firm). The vasa and epididymides were palpated, and the presence of a clinical varicocele was determined with the patient in the upright and supine posi tions as well as following a Valsalva maneuver. Objective measurements of testicular size and consistency were then performed. Calipers were used to measure testicular dimensions to the nearest millimeter along the superior-inferior, anterior-posterior, and medial-lateral axes. Tes ticular tonometry was performed using a Mac kay-marg Tonometer (Biotronics, Redding, CA). This instrument, which costs approximately $1000, includes a hand-held probe containing a ceramic activating rod whose movements are de tected and amplified to produce a visual tono gram. As applied in ophthalmology, the instru ment detects intraocular pressure, acting through the flattened cornea against the activating rod. The Mackay-Marg instrument applies elements of both applanation and impression. ts estima tion of pressure is virtually independent of ocular rigidity and corneal stiffness.6 t is considered the most accurate instrument for measurement of in traocular pressure in edematous or abnormal cor neas, 7 and for these reasons it was selected for measurement of testicular consistency. The tes ticular consistency was measured through the skin of the scrotum stretched over the testicular surface. The instrument was calibrated according to manufacturer's instructions prior to assess ment of each testicle. Ten replicate measure ments were made at each of four standard sites along the superior-inferior axis of the testis on its anterior surface (Fig. 1 ). All measurements were made with the patients in a recumbent position and without Valsalva maneuver. Approximately 10 minutes were required to learn the tonometry technique, and the measurements could be per formed on each patient in less than 5 minutes. The tonogram for each subject included 0 deflec tions per testicle (ten measurements for each of four sites). The height of each deflection was mea sured from the baseline (Fig. ), and the mean tonometry value for each testicle was calculated from the 0 measurements. For some compari " sons a mean tonometry value was also calculated for both testicles from 80 measurements. SEMEN EVALUATON A semen specimen was obtained by masturba tion from each man after at least days of sexual Fertility and Sterility

3 MEAN.50 MEAN 8. 5 A. Testicles N ormal Consistanoy B. Te s t i c l e s Soft Conslst ancy C. Soft Left Testicle with Varicocele Figure The tonogram for each testicle includes 0 deflections ob tained at four sites on the testicular surface. The height of each deflection is measured in millimeters (one box on the tonopaper equals 1 mm), and the mean value for the 0 measurements is the tonometry value for the testis. Examples are shown of testicles with normal consistency (A), soft consis tency (B), and unilateral soft consistency associated with var icocele (C). abstinence. The semen volume was measured, and the sperm concentration was determined by hemocytometer counts. A videotape recording of the semen was made at 7 C within hours of collection, and the tape was subsequently ana lyzed for percent sperm motility and mean swim ming speed. 8 An air-dried seminal smear was stained by the Papanicolaou technique, the im ages of the stained spermatozoa were transmitted to a video screen, 9 and the smear was assessed for the percentage of oval sperm (head length, to 5 j.lm; head width, to j.lm) with the use of a transparent overlay calibrated to metric stan dards. 10 STATSTCAL ANALYSS Tonometry data on the individual testes from the overall group of 8 men were analyzed for examination of the correlation between testicular tonometry values and the three clinical catego ries of testicular size and consistency; a nonpara metric (Spearman rho) correlation was used. To examine whether tonometry readings differ among the testicles classified in the three clinical categories of consistency and size, we used onevol., No. 6, June 1985 way analysis of variance, with the clinical catego ries taken as a fixed effect. We used Pearson cor relation to examine relationships between tonom etry values and parameters of semen quality. A correlation of P < 0.05 was considered significant. Differences between the right and left testicles in tonometry values or testicular dimensions were assessed with the use of a paired t-test. For examination of the effect of varicocele on testicular size and consistency, the testicular measurements and tonometry values of the right versus the left testicles were examined in the group of men from the infertility clinic with pal pable left varicoceles (n 1). None of these men had a right varicocele. This group was compared with the group composed of all remaining men (n 5), after exclusion of those with azoospermia (n 8) and those with a history of varicocelec tomy (n 8). The testicular measurements and tonometry values of the men with azoospermia were also compared with this group of 5 men. The groups were compared by a two-tailed t-test for independent groups. Where variances of the two groups under consideration were relatively equal, a pooled variance estimate was used for calculation of the t value. f the two groups showed significantly unequal variances, a value based upon a separate variance estimate was used, along with adjusted degrees of freedom. All statistical analyses were carried out with the use of the Statistical Package for the Social Sci ences. 11 RE SULTS TESTCULAR CONSSTENCY AS ASSESSED SUBJECTVELY AND BY TONOMETRY The relationship between the mean tonometry value for each testicle (0 measurements) and the clinical impression of testicular consistency was evaluated for the total group of 8 men. The to nometry value was found to be significantly corre lated with the clinical impression; i.e., when the tonometry value was small, the testicles were perceived as soft (for the right and left sides, r8 0.5 arid r8 0.7, respectively). There was a significant difference in tonometry readings be tween testicles classified as soft, normal, and firm, with firm testicles showing the highest to nometry readings and soft testicles showing the lowest readings (Table 1 ). Lewis e t al. Human testicular tonometry 91

4 Table 1. The Relationship of Mean Testicular Tonometry Valuesa to the Clinical mpression of Testicular Size and Consistency Consistency Right testicle Left testicle Size Soft Normal Firm Small Normal Large amean tonometry values standard error of the mean for each testicle (0 measurements) were compared with the clinical impression of the testicle. The differences in tonometry values between the groups were significant (P < 0.0). RELATONSHP OF TESTCULAR TONOMETRY TO TESTCULAR SZE The tonometry value was also significantly cor related with the clinical impression of testicular size (for the right and left sides, r8 0.8 and r8 0.0, respectively). Among testicles classified as small, normal, and large, there was a signifi cant difference in tonometry readings. Large tes tes showed the highest readings, while small tes tes had the lowest (Table 1 ). When the testicular measurements were analyzed in relation to the mean tonometry value, the right side showed sig nificant correlations between tonometry readings and all measurements. For the superior-inferior, medial-lateral, and anterior-posterior dimen 0.0, 0.7, and 0.8, respectively. On sions, r the left side, however, only the superior-inferior dimension was significantly correlated with the tonometry value (r 0.0). COMPARSON O F RGHT AN D LEFT TESTCULAR CHARACTE RSTCS The mean testicular dimensions in all three axes are shown for the right and left testicles in Table. Mean tonometry values for the right and left testicles at the four measurement sites are depicted in Figure. The group of men with azoo spermia had significantly smaller left and right testicles in all dimensions than the other men in the study. However, when the men with varico celes were considered as a group, only the right testicles of the azoospermic men were significant ly smaller than the comparable testicles of the men with varicoceles. The dimensions of the left testicles were not significantly different for the men with azoospermia and for the men with vari coceles. Also, in the men with varicocele, the left testicle was significantly smaller than the paired right testicle in two of three dimensions (Table ). Examination of the tonometry values for right and left testicles, as shown in Figure and Table, revealed a significantly larger mean tonometry value for the right testicle in all men except for those with azoospermia, in whom no asymmetry was apparent. The difference in mean tonometry values between the right and left testicles was most significant in the group with varicocele. The only significant difference in tonometry values between the three groups of men was in the mean value for the left testicles of men with varicoceles, which differed significantly from the mean value for the left testicles of the other men. RELATONSHP OF TESTCULAR TONOMETRY TO PARAMETERS OF SEMEN QUALTY When all 8 men in the study were considered, there was no significant correlation between the Table. Measurements of Testicular Dimensionsa for the R ight and Left Testicles in the Three Groups of Study Subjects Group Azoospermia (n 8) Varicocele (n 1) Other men (n 5) Right testicular dimensions Superior-inferior Medial-lateral Left testicular dimensions Anterior-posterior Superior-inferior Medial-lateral Anterior-posterior amean values in millimeters standard error of the mean are shown. There were no significant differences between the dimensions of the right and left testicles except in men with varicocele in whom the superior-inferior and anterior-posterior dimensions of the left testicle were smaller (P < 0.0). The testicular dimensions (right and left) of men with azoospermia were smaller than those of "other men" (P < 0.0). The right testicles of men with azoospermia were smaller than the right testicles of men with varicocele (P < 0. 0), but the dimensions of the left testicles of men with azoospermia and varicocele were not significantly different. 91 Lewis et al. Human testicular tonometry Fertility and Sterility

5 1 0.0 V) (.!) z Ci "' Ll 0:: >0:: 1Ll ::::!! 0 z AZOOSPERMA (n, 8) ALL MEN ( n, 8l H't VARCOCELE (n ' 1)... 1\ H- TEST C U LAR S T E OTH ER MEN ' " ' 5) Figure Tonometry values in millimeters (mean standard error of the mean) for the right testicle () and left testicle (e) at each testicular site (ten deflections per site) in the four groups of men. The mean tonometry values for all four sites (0 deflec tions) are given in Table. tonometry value and any parameter of semen quality. n the group of men with varicocele there was a significant positive correlation between the mean tonometry value for both testicles and the sperm concentration (r 0.67). n the compari son group of 5 men, there was a significant posi tive correlation between the mean tonometry val ue and the percentage of oval sperm (r 0. 1 ). DSCUSSON n this study, we have demonstrated the as sessment of human testicular consistency by to nometry. The tonometry readings reflect the firmness of the testes as palpated on the physical examination and provide a permanent, objective record of testicular consistency. These measure ments complement measurements of testicular size and may be used for statistical comparisons of testicular characteristics among individuals or groups of study subjects. The tonometry values recorded in this study revealed a previously unrecognized asymmetry in testicular consistency (right testicle firmer than left testicle), which was seen in all groups of men except those with presumed testicular failure. n terestingly, a similar asymmetry in testicular weight has also been reported. n a recent study of paired autopsy specimens, left testicles were found to be approximately 10% smaller than right Vol., No. 6, June 1985 testicles. 1 n the present study, the difference in consistency of right and left testicles was accen tuated in men with varicoceles. n the group of men with varicoceles a similar asymmetry in tes ticular size was also recorded, but no significant differences in the dimensions of the paired testi cles were detected in the other men in this study. These observations of asymmetry in testicular di mensions of men with varicocele agree with the findings of Lipshultz and Corriere, who also found testicular size in men with varicoceles to be smaller in general when compared with that in men having idiopathic oligospermia. n the pres ent study the testicular dimensions of men with varicocele were not significantly smaller than those of the other men in the study. n general, the men with azoosperm i a had significantly smaller testicles than the other men; but interest ingly, the left testicles of the azoospermic men were not different in size from the left testicles of men with varicoceles. n the group of men with varicoceles the tonom etry value was positively correlated with the sperm concentration, and in the men without var icocele a positive correlation was demonstrated with normal sperm morphology. The only other species in which testicular tonometry has been studied in relation to semen quality is the bovine. n agreement with the present study, bovine tes ticular tonometry values were also found to corre late with assessments of normal sperm morphol ogy.a The measurements of testicular consistency ob tained by tonometry cannot distinguish between the contributions of the germinal elements and the other, supportive structures of the testes. Thus, the tonometry readings alone did not iden tify the group of men with testicular failure, al though the traditional combination of measure ments describing testicular size and consistency would have done so. Nevertheless, tonometry Table. Measurements of Testicular Consistencya for the Right and Left Testicles in the Three Groups of Study Subjects Group Azoospermia (n 8) Varicocele (n 1) Other men (n 5) Right testicular tonometry value Left testicular tonometry value amean values for 0 measurements in millimeters stan dard error of the mean are shown. The difference in mean tonometry values for the right and left testicles was signifi cantly different for the group of men with varicocele (P < 0.005) and for the group of "other men" (P < 0.05). Lewis et al. Human testicular tonometry 915

6 may provide unique clinical information because of the apparently normal phenomenon of right versus left asymmetry in human testicular con sistency. This asymmetry was accentuated in the presence of varicocele, where dysfunction of the germinal epithelium may also be asymmetric. The normal asymmetry of testicular consistency was not detected in the cases of presumed tes ticular failure where there was likely to be little or no germinal epithelium present in either tes tis. REFERENCES 1. Hotchkiss RS: Fertility in Men. Philadelphia, J. B. Lip pincott Co., 1 9. Lipshultz L, Carriere JN Jr: Progressive testicular atro phy in the varicocele patient. J Urol 1 17 : 175, Hahn J, Foote RH, Cranch ET: Tonometer for measuring testicular consistency of bulls to predict semen quality. J Anim Sci 9:8, Whorton D: Field studies: lessons learned. Teratogenesis Carcinog Mutagen :5, Lewis et al. Human testicular tonometry 5. Overstreet JW: Assessment of disorders of spermatogene sis. n Reproduction: The New Frontier in Occupational and Environmental Health Research, Edited by JE Loc key. New York, Alan Liss, 1 98, p Moses RA : The Mackay-Marg Tonometer: a report to the committee on standardization of tonometers. Trans Am Acad Ophthalmol Otolaryngol 66:88, McMillan F, Forster RK: Comparison of Mackay-Marg, Goldmann, and Perkins Tonometers in abnormal corneas. Arch Ophthalmol 9:0, Katz DF, Overstreet JW: Sperm motility assessment by videomicrography. Fertil Steril 5: 188, Overstreet JW, Price JM, Blazak WF, Lewis EL, Katz DF: Simultaneous assessment of human sperm motility and morphology by videomicrography. J Urol 16:57, Katz DF, Diel L, Overstreet JW: Differences in the movement of morphologically normal and abnormal hu man seminal spermatozoa. Biol Reprod 6:566, Nie NH, Hull CH, Jenkins JG, Steinbrenner K, Bent DH: Statistical Package for the Social Sciences, Second edi tion. New York, McGraw-Hill, Johnson L, Petty CS, Neaves WB: nfluence of age on sperm production and testicular weights in men. J Reprod Fertil 70: 1 1, 1 98 Fertility and Sterility