Effect of Sustained Joint Loading on TMJ Disc Nutrient Environment

The temporomandibular joint (TMJ) disc nutrient environment profoundly affects cell energy metabolism, proliferation, and biosynthesis. Due to technical challenges of in vivo measurements, the human TMJ disc extracellular nutrient environment under load, which depends on metabolic rates, solute diffusion, and disc morphometry, remains unknown. Therefore, the study objective was to predict the TMJ disc nutrient environment under loading conditions using combined experimental and computational modeling approaches. Specifically, glucose consumption and lactate production rates of porcine TMJ discs were measured under varying tissue culture conditions (n = 40 discs), and mechanical strain-dependent glucose and lactate diffusivities were measured using a custom diffusion chamber (n = 6 discs). TMJ anatomy and loading area were obtained from magnetic resonance imaging of healthy human volunteers (n = 11, male, 30 ± 9 y). Using experimentally determined nutrient metabolic rates, solute diffusivities, TMJ anatomy, and loading areas, subject-specific finite element (FE) models were developed to predict the 3-dimensional nutrient profiles in unloaded and loaded TMJ discs (unloaded, 0% strain, 20% strain). From the FE models, glucose, lactate, and oxygen concentration ranges for unloaded healthy human TMJ discs were 0.6 to 4.0 mM, 0.9 to 5.0 mM, and 0% to 6%, respectively, with steep gradients in the anterior and posterior bands. Sustained mechanical loading significantly reduced nutrient levels (P < 0.001), with a critical zone in which cells may die representing approximately 13.5% of the total disc volume. In conclusion, this study experimentally determined TMJ disc metabolic rates, solute diffusivities, and disc morphometry, and through subject-specific FE modeling, revealed critical interactions between mechanical loading and nutrient supply and metabolism for the in vivo human TMJ disc. The results suggest that TMJ disc homeostasis may be vulnerable to pathological loading (e.g., clenching, bruxism), which impedes nutrient supply. Given difficulties associated with direct in vivo measurements, this study provides a new approach to systematically investigate homeostatic and degenerative mechanisms associated with the TMJ disc.

Mechanobehavior and Ontogenesis of the Temporomandibular Joint

Craniofacial secondary cartilages of the mandibular condyle and temporomandibular joint (TMJ) eminence grow in response to the local mechanical environment. The intervening TMJ disc distributes normal loads over the cartilage surfaces and provides lubrication. A better understanding of the mechanical environment and its effects on growth, development, and degeneration of the TMJ may improve treatments aimed at modifying jaw growth and preventing or reversing degenerative joint disease (DJD). This review highlights data recorded in human subjects and from computer modeling that elucidate the role of mechanics in TMJ ontogeny. Presented data provide an approximation of the age-related changes in jaw-loading behaviors and TMJ contact mechanics. The cells of the mandibular condyle, eminence, and disc respond to the mechanical environment associated with behaviors and ultimately determine the TMJ components' mature morphologies and susceptibility to precocious development of DJD compared to postcranial joints. The TMJ disc may be especially prone to degenerative change due to its avascularity and steep oxygen and glucose gradients consequent to high cell density and rate of nutrient consumption, as well as low solute diffusivities. The combined effects of strain-related hypoxia and limited glucose concentrations dramatically affect synthesis of the extracellular matrix (ECM), which limit repair capabilities. Magnitude and frequency of jaw loading influence this localized in situ environment, including stem and fibrocartilage cell chemistry, as well as the rate of ECM mechanical fatigue. Key in vivo measurements to characterize the mechanical environment include the concentration of work input to articulating tissues, known as energy density, and the percentage of time that muscles are used to load the jaws out of a total recording time, known as duty factor. Combining these measurements into a mechanobehavioral score and linking these to results of computer models of strain-regulated biochemical events may elucidate the mechanisms responsible for growth, maintenance, and deterioration of TMJ tissues.

Mechanobehaviour in dolichofacial and brachyfacial adolescents

OBJECTIVES

To test whether mechanobehaviour (temporomandibular joint (TMJ) loads, jaw muscle use) was different between facial types and correlated with ramus height (Condylion-Gonion, mm).

SETTING AND SAMPLE POPULATION

University of Missouri-Kansas City (UMKC) Orthodontic Clinic. Ten dolichofacial and ten brachyfacial adolescents (Sella-Nasion-Gonion-Gnathion (SN-GoGn) angles ≥37° and ≤27°, respectively) consented to participate.

MATERIALS AND METHODS

Numerical models calculated TMJ loads for a range of static biting based on subjects' three-dimensional anatomy. Subjects were trained to record jaw muscle electromyography (EMG) over 2 days and 2 nights in their natural environments. Laboratory EMG/bite-force calibrations determined subject-specific EMG for 20 N bite-force (T_20Nave ). Jaw muscle use via duty factors (DF=muscle activity duration/total recording time, %) was determined from day and night recordings for muscle-specific thresholds from ≥5% to ≥80%T_20Nave . ANOVA and Tukey's HSD post hoc tests assessed for group differences in mechanobehaviour (TMJ loads, DFs). Regression modelling correlated subjects' normalized TMJ loads, DFs and ramus height.

RESULTS

Dolichofacial compared to brachyfacial subjects produced significantly higher (P<.05) TMJ loads, where ipsilateral loads were ≥20% larger for some biting angles, but had significantly less (all P<.05) masseter (day, night) and temporalis (night) DFs. Regression analysis showed a significant relationship amongst normalized TMJ loads, masseter DF and ramus height (R² =.49).

CONCLUSIONS

Mechanobehaviour showed significant differences between facial types and was correlated with ramus height.

Fluid pressurization and tractional forces during TMJ disc loading: A biphasic finite element analysis

OBJECTIVES

To investigate the ploughing mechanism associated with tractional force formation on the temporomandibular joint (TMJ) disc surface.

SETTING AND SAMPLE POPULATION

Ten left TMJ discs were harvested from 6- to 8-month-old male Yorkshire pigs.

MATERIALS AND METHODS

Confined compression tests characterized mechanical TMJ disc properties, which were incorporated into a biphasic finite element model (FEM). The FEM was established to investigate load carriage within the extracellular matrix (ECM) and the ploughing mechanism during tractional force formation by simulating previous in vitro plough experiments.

RESULTS

Biphasic mechanical properties were determined in five TMJ disc regions (average±standard deviation for aggregate modulus: 0.077±0.040 MPa; hydraulic permeability: 0.88±0.37×10^-3 mm⁴ /Ns). FE simulation results demonstrated that interstitial fluid pressurization is a dominant loading support mechanism in the TMJ disc. Increased contact load and duration led to increased solid ECM strain and stress within, and increased ploughing force on the surface of the disc.

CONCLUSION

Sustained mechanical loading may play a role in load carriage within the ECM and ploughing force formation during stress-field translation at the condyle-disc interface. This study further elucidated the mechanism of ploughing on tractional force formation and provided a baseline for future analysis of TMJ mechanics, cartilage fatigue and early TMJ degeneration.

Jaw closing movement and sex differences in temporomandibular joint energy densities

Energy densities (ED, mJ/mm3 ) quantify mechanical work imposed on articular cartilages during function. This cross-sectional study examined differences in temporomandibular joint (TMJ) ED during asymmetric versus symmetric jaw closing in healthy females versus males. ED component variables were tested for differences between and within sexes for two types of jaw closing. Seventeen female and 17 male subjects gave informed consent to participate. Diagnostic criteria for temporomandibular disorders and images (magnetic resonance (MR), computed tomography) were used to confirm healthy TMJ status. Numerical modelling predicted TMJ loads (Fnormal ) consequent to unilateral canine biting. Dynamic stereometry combined MR imaging and jaw-tracking data to measure ED component variables during 10 trials of each type of jaw closing in each subject's TMJs. These data were then used to calculate TMJ ED during jaw closing asymmetrically and symmetrically. Paired and Student's t tests assessed ED between jaw closing movements and sexes, respectively. Multivariate data analyses assessed ED component variable differences between jaw closing movements and sexes (α = 0.05). Contralateral TMJ ED were 3.6-fold and significantly larger (P < .0001) during asymmetric versus symmetric jaw closing, due to significantly larger (P ≤ .001) distances of TMJ stress-field translation in asymmetric versus symmetric movement. During asymmetric jaw closing, contralateral TMJ ED were twofold and significantly larger (P = .036) in females versus males, due to 1.5-fold and significantly smaller (P ≤ .010) TMJ disc cartilage volumes under stress fields in females versus males. These results suggest that in healthy individuals, asymmetric compared to symmetric jaw closure in females compared to males has higher TMJ mechanical fatigue liabilities.

Speed of human tooth movement in growers and non-growers: Selection of applied stress matters

OBJECTIVES

To test that the speed of tooth translation is not affected by stress magnitude and growth status.

SETTING AND SAMPLE POPULATION

Advanced Education Orthodontic clinics at the Universities of Nebraska Medical Center and Missouri-Kansas City. Forty-six consenting subjects with orthodontic treatment plans involving maxillary first premolar extractions.

MATERIALS AND METHODS

This randomized split-mouth study used segmental mechanics with definitive posterior anchorage and individual vertical-loop maxillary canine retraction appliances and measured three-dimensional tooth movements. Height and cephalometric superimposition changes determined growing (G) and non-growing (NG) subjects. Subjects were appointed for 9-11 visits over 84 days for maxillary dental impressions to measure three-dimensional tooth movement and to ensure retraction forces were continuously applied via calibrated nitinol coil springs. Springs were custom selected to apply two different stresses of 4, 13, 26, 52 or 78 kPa to maxillary canines in each subject. Statistical analyses (α=0.050) included ANOVA, effect size (partial η² ) and Tukey's Honest Significant Difference (HSD) and two-group t tests.

RESULTS

Distolateral translation speeds were 0.034±0.015, 0.047±0.019, 0.066±0.025, 0.068±0.016 and 0.079±0.030 mm/d for 4, 13, 26, 52 and 78 kPa, respectively. Stress significantly affected speed and partial η² =0.376. Overall, more distopalatal rotation was shown by teeth moved by 78 kPa (18.03±9.50º) compared to other stresses (3.86±6.83º), and speeds were significantly higher (P=.001) in G (0.062±0.026 mm/d) than NG subjects (0.041±0.019 mm/d).

CONCLUSIONS

Stress magnitude and growth status significantly affected the speed of tooth translation. Optimal applied stresses were 26-52 kPa, and overall speeds were 1.5-fold faster in G compared to NG subjects.

TMJ energy densities in healthy men and women

OBJECTIVE

Cartilage fatigue, due to mechanical work, may account for the early development of degenerative joint disease (DJD) in the temporomandibular joint (TMJ), and why women are three times more likely to be afflicted. This study tested for gender differences in mechanical energy densities in women and men with healthy TMJs.

DESIGN

Eighteen women and eighteen men gave informed consent. Research diagnostic criteria including imaging were used to ensure that subjects' TMJs were normal, without disc displacement or signs of DJD. Numerical modeling determined TMJ loads (F_normal). Jaw tracking and three-dimensional dynamic stereometry characterized individual-specific data of stress-field dynamic mechanics during 10 symmetrical jaw closing cycles. These data were used to estimate tractional forces (F_traction). Energy densities were then calculated, where: Energy Density = W/Q (W = work done or mechanical energy input = F_traction*distance of stress-field translation, Q = volume of cartilage). Two-way analysis of variance (ANOVA) and follow-up two-group comparisons tested mean energy densities for ipsilateral and contralateral TMJs in women vs men.

RESULTS

Mean energy densities ± standard deviations in ipsilateral and contralateral TMJs in women were 9.0 ± 9.7 and 8.4 ± 5.5 mJ/mm³, respectively, and were significantly larger (P = 0.004 and 0.001, respectively) compared to ipsilateral and contralateral TMJs in men, which were 5.6 ± 4.2 and 6.3 ± 4.2 mJ/mm³, respectively.

CONCLUSIONS

Energy densities were significantly larger in healthy TMJs of women than men. Larger TMJ energy densities during normal jaw functions could predispose earlier mechanical fatigue of the TMJ disc.

A pilot study of nocturnal temporalis muscle activity in TMD diagnostic groups of women

Temporomandibular disorder (TMD) incidences are believed to be related to parafunctional behaviours like teeth clenching. This pilot study aimed to (i) develop an automated clench-detection algorithm, and (ii) apply the algorithm to test for differences in nocturnal clenching in women with and without TMD. Subjects gave informed consent to participate. Adult women were categorised using Diagnostic Criteria for TMD according to presence/absence (+/-) of both TM joint disc placement (DD) and chronic pain (P) into two groups (+DD+P, -DD-P) with 12 subjects each. Surface temporalis electromyography was recorded during oral tasks performed by subjects at two laboratory sessions. The data were used to characterise muscle activity per N of bite force (μV/N) for each subject, develop the clench-detection algorithm and test its accuracy. Ambulatory surface temporalis electromyography was self-recorded by each subject over three nights and analysed using the algorithm and bite force (N) versus muscle activity μV/N calibrations. Bonferroni-adjusted homoscedastic t-tests assessed for significant between-group differences in clenching (P < 0·05). Sensitivity, specificity and accuracy of algorithm-detected laboratory clenches were all ≥96%. During self-recordings 95% of clenches had durations of <4 s and peak forces of <10 N in both groups. Mean clench durations were significantly longer (P = 0·042) in +DD+P (1·9 ± 0·8 s) than -DD-P subjects (1·4 ± 0·4 s). Mean temporalis duty factors (%clench time/total recording time) were significantly larger (P = 0·041) in +DD+P (0·47 ± 0·34%) than -DD-P (0·26 ±0·22%) subjects. Nocturnal temporalis muscle activities detected by a validated algorithm were longer per clench and recording time in +DD+P compared to -DD-P women.

Laboratory Stresses and Tractional Forces on the TMJ Disc Surface

The etiology of degenerative disease of the TMJ may involve fatigue produced by surface tractional forces and compressive stresses. This study tested the time-dependent effects of compressive loading and stress-field translation on TMJ disc-surface tractional forces and stresses. In laboratory experiments with 50 porcine discs, an acrylic indenter imposed 10 N static loads for 10 and 60 sec, followed by translation of the loaded indenter along the mediolateral axis of the disc. Maximum tractional forces were found to occur following 60 sec of static loading (p < 0.001), and increased with translation velocity (R2 = 0.73); whereas maximum compressive stresses occurred after 10 sec of static loading (p < 0.001). Overall, the results were consistent with current mechanical theories of the time-dependent effects of compressive loading of cartilage.

Personalized and precision orthodontic therapy

OBJECTIVE

To bring together orthodontic stakeholders from academics, industry, and private practice for a series of thematically focused workshops to explore and develop the transfer of novel approaches into clinical orthodontic practice.

SETTING AND SAMPLE POPULATION

Twenty-seven invited speakers, eight poster presenters, and participants of the Consortium for Orthodontic Advances in Science and Technology (COAST) 2014 Innovators' Workshop at the Eaglewood Resort and Spa, Itasca, Illinois, September 11-14, 2014.

MATERIAL AND METHODS

Five themed sessions involving between 4-7 presentations followed by panel discussions were organized. The aims of the discussion sessions were to highlight important findings and consider the strength of evidence for these, indicate next steps and needed research or technological developments to move forward, and to weigh the expected benefits from these findings and steps to implement in clinical practice.

RESULTS

Among important areas for attention identified were need for multiscale and multispecies modeling and experimentation for interspecies translation of results; large-scale collaborative efforts within the profession to address the need for adequate sample sizes for future genetic studies of complex traits such as malocclusion; a consortium approach to improve new technologies such as intra-oral scanning and 3D imaging by establishing standards; and harnessing the growing body of knowledge about bone biology for application in orthodontics.

CONCLUSIONS

With increased awareness of the potential of current and emerging technologies, translation of personalized and precision approaches in the field of orthodontics holds ever-increasing promise.

Infield masticatory muscle activity in subjects with pain-related temporomandibular disorders diagnoses

OBJECTIVES

Pain-related temporomandibular disorders (TMDs) are the most prevalent conditions among TMDs. There is contrasting evidence available for association of pain-related TMD and masticatory muscle activity (MMA). The present investigation assesses the associations between MMA levels of masseter and temporalis muscles during awake and sleep among pain-related TMD diagnostic groups.

SETTING AND SAMPLE POPULATION

The department of Oral Diagnostic Sciences, University at Buffalo. Twenty females and six males participated in this study.

MATERIAL AND METHODS

Using the diagnostic criteria for temporomandibular disorders (DC-TMDs), participants were diagnostically categorized. Subjects used a custom monitoring system, which recorded infield muscle activities. A factorial model tested for association between independent variable (muscle, time period, MMA level, and diagnostic group) effects and the logarithm of MMA. Greenhouse-Geisser test was used to determine any statistically significant associations (p≤0.003).

RESULTS

No statistically significant association was found between four-way, three-way, and two-way analyses. However, among the main effects, range of magnitudes was the only variable to be statistically significant. Although the data suggest a trend of increased masseter MMA in the pain-related TMD diagnoses group both during awake and sleep time periods, such observation is not maintained for the temporalis muscle. In addition, temporalis MMA was found to be higher in the pain-related TMD diagnoses group only at extreme activity levels (<25 and ≥80% ranges).

CONCLUSION

This data support the association between masticatory muscle hyperactivity and painful TMD conditions.

Greater extent of prostate inflammation in negative biopsies is associated with lower risk of prostate cancer on repeat biopsy: results from the REDUCE study

BACKGROUND

To evaluate whether the extent of baseline acute prostate inflammation (API) and chronic prostate inflammation (CPI) was associated with risk of prostate cancer (PCa) at 2-year repeat prostate biopsy in a clinical trial with systematic biopsies independent of PSA.

METHODS

A retrospective analysis of 6065 men with a negative baseline biopsy in the reduction by dutasteride of PCa events (REDUCE) trial undergoing 2-year biopsy. API and CPI extent (percentage of cores involved) and PCa (present or absent) were assessed by central pathology. The association of baseline API and CPI with PCa at the 2-year biopsy was evaluated with logistic regression in uni- and multivariable analyses.

RESULTS

API extent was classified as absent or involving 1-25%, 26-50%, 51-75% and >75% cores in 5140 (85%), 742 (12%), 151 (2%), 17 (<1%) and 15 (<1%) cases, respectively. CPI extent was classified as absent or involving 1-25%, 26-50%, 51-75% and >75% cores in 1367 (22%), 2532 (42%), 1474 (24%), 397 (7%) and 295 (5%) cases, respectively. More extensive API was associated with younger age, lower PSA and lower prostate volume, while more extensive CPI was associated with older age, lower PSA and higher prostate volume (all P<0.01). In both uni- and multivariable analyses, API and CPI extent were associated with lower risk of PCa at the 2-year biopsy (both P<0.01).

CONCLUSIONS

In a cohort of men undergoing repeat prostate biopsy 2 years after a negative baseline biopsy, a greater extent of baseline API and CPI was independently associated with lower PCa risk.

Association between waking-state oral parafunctional behaviours and bio-psychosocial characteristics

The term 'oral parafunctional behaviours' encompasses behaviours that are different from those required for, or associated with, physiological functional needs such as mastication, communication, swallowing or breathing. Previous reports have associated waking-state oral parafunctional behaviours with biopsychosocial characteristics such as female gender, presence of psychological symptoms, intensity of pain and pain-related temporomandibular disorders (TMD) diagnosis. However, the findings have been inconsistent, possibly due to methodological limitations and differences. In the present investigation, we aim to determine whether any association is present between waking-state oral parafunctional behaviours and biopsychosocial characteristics. All participants were investigated using a set of standardised and validated self-reporting questionnaires and diagnostic criteria for temporomandibular disorders (DC/TMD) examination protocol for clinical characterisation. Univariate analysis found that self-reported waking-state oral parafunctional behaviours were statistically significantly associated with presence of anxiety, depression and physical symptoms, pain intensity and TMD diagnosis. However, forward model multiple linear regression analysis indicated that only self-reported presence of physical and depression symptoms could explain statistically significant portions of the variance in self-reported waking-state oral parafunctional behaviours.

Modeling of muscle forces in humans with and without temporomandibular joint disorders

OBJECTIVES

Subjects with/without temporomandibular joint disorders (TMJD) were tested for differences in muscle forces.

SETTING AND SAMPLE POPULATION

School of Dental Medicine, University at Buffalo. Ninety-one subjects were classified in four groups based on the presence/absence (±) of chronic myofascial and/or TMJ pain (P) and bilateral disc displacement (DD).

MATERIAL AND METHODS

Validated numerical models employed an organizational objective and subjects' anatomy to calculate masticatory muscle forces during static biting. anova and Holm's step-down procedure post hoc tests assessed group differences. Theoretical geometries, representing the range of subjects' muscle orientations, were surveyed via numerical models to identify key combinations resulting in high muscle forces. Effect size (Cohen's d) and anova/post hoc tests assessed group differences in key muscle orientations.

RESULTS

+P-DD subjects had significantly higher muscle forces, especially for lateral pterygoid muscles, compared to the other groups (p<0.01) for bite forces that were directed posteromedially or posterolaterally on mandibular molars and posteriorly and slightly medially on mandibular incisors. Key muscle orientations for peak lateral pterygoid muscle forces were identified, and group comparisons showed mean orientation in +P-DD compared to other diagnostic groups was ≥5° more upright for masseter and ≥3° more posteriorly directed for temporalis muscles (all Cohen's d≥0.8).

CONCLUSION

Predicted lateral pterygoid muscle forces were significantly higher in +P-DD compared to other groups for specific biting conditions and were attributable, in part, to differences in masseter and temporalis muscle orientations.

A pilot study of ambulatory masticatory muscle activities in temporomandibular joint disorders diagnostic groups

OBJECTIVE

To determine differences in masticatory muscle usage between temporomandibular joint disorders diagnostic groups.

SETTING AND SAMPLE POPULATION

Seventy-one informed and consented subjects (27 men; 44 women) participated at the University at Buffalo.

MATERIAL AND METHODS

Research diagnostic criteria and imaging data were used to categorize subjects according to the presence/absence +/- of TMJ disc placement (DD) and chronic pain (P) (+DD+P, n=18; +DD-P, n=14; -DD-P, n=39). Electromyographic (EMG)/bite-force calibrations determined subject-specific masseter and temporalis muscle activities per 20 N bite-force (T20N , μV). Over 3 days and nights, subjects collected EMG recordings. Duty factors (DFs, % of recording time) were determined based on threshold intervals (5-9, 10-24, 25-49, 50-79, ≥80% T20N ). anova and Tukey-Kramer post hoc tests identified 1) diagnostic group differences in T20N and 2) the effects of diagnostic group, gender, time and interval on muscle DFs.

RESULTS

Mean (±SE) temporalis T20N in +DD+P subjects was significantly higher (71.4±8.8 μV) than masseter T20N in these subjects (19.6±8.8 μV; p=0.001) and in -DD-P subjects (25.3±6.0 μV, p=0.0007). Masseter DFs at 5-9% T20N were significantly higher in +DD-P women (3.48%) than +DD-P men (0.85%) and women and men in both other diagnostic groups (all p<0.03), and in +DD+P women (2.00%) compared to -DD-P men (0.83%; p=0.029). Night-time DFs at 5-9% T20N in +DD-P women (1.97%) were significantly higher than in -DD-P men (0.47%) and women (0.24%; all p<0.01).

CONCLUSIONS

Between-group differences were found in masticatory muscle activities in both laboratory and natural environmental settings.

Diagnostic group differences in temporomandibular joint energy densities

OBJECTIVES

Cartilage fatigue, due to mechanical work, may account for precocious development of degenerative joint disease in the temporomandibular joint (TMJ). This study compared energy densities (mJ/mm³) in TMJs of three diagnostic groups.

SETTING AND SAMPLE POPULATION

Sixty-eight subjects (44 women, 24 men) gave informed consent. Diagnostic criteria for temporomandibular disorders (DC/TMD) and imaging were used to group subjects according to presence of jaw muscle or joint pain (+P) and bilateral disk displacement (+DD).

MATERIAL AND METHODS

Subjects (+P+DD, n=16; -P+DD, n=16; and -P-DD, n=36) provided cone-beam computed tomography and magnetic resonance images, and jaw-tracking data. Numerical modeling was used to determine TMJ loads (Fnormal). Dynamic stereometry was used to characterize individual-specific data of stress-field dynamics during 10 symmetrical jaw-closing cycles. These data were used to estimate tractional forces (Ftraction). Energy densities were then calculated as W/Q (W=work done or mechanical energy input=tractional force×distance of stress-field translation, Q=volume of cartilage). anova and Tukey-Kramer post hoc analyses tested for intergroup differences.

RESULTS

Mean±standard error energy density for the +P+DD group was 12.7±1.5 mJ/mm³ and significantly greater (all adjusted p<0.04) when compared to -P+DD (7.4±1.4 mJ/mm³) and -P-DD (5.8±0.9 mJ/mm³) groups. Energy densities in -P+DD and -P-DD groups were not significantly different.

CONCLUSION

Diagnostic group differences in energy densities suggest that mechanical work may be a unique mechanism, which contributes to cartilage fatigue in subjects with pain and disk displacement.

Prevalence and Clinical Management of Complicated Urinary Tract Infections in Italy: a Prospective Multicenter Epidemiological Study in Urological Outpatients

The objectives of the study were to evaluate the prevalence of complicated urinary tract infections among Italian patients attending the urologist's office, to describe the frequency of different complication factors, the encountered bacterial pathogens and the clinical attitude of urologists in management of complicated urinary tract infections (CUTIs). The study was a prospective, multicenter study which was undertaken by office urologists throughout Italy. During the May-June 2002 timeframe, the prevalence of each urologist's diagnosis of CUTIs was noted for a 4-week slot. The prevalence of CUTIs in over 13,000 patients observed was 10.8% (n = 1201), with a trend (not statistically significant) of higher figures in the South/Islands (12.2%) with respect to Center (11.4%) or North (8.7%) of Italy. We have confirmed the significant relevance of CUTI among the Italian patients attending the urologist office and the clinical data collected may contribute to improve the diagnosis and empiric therapy of complicated urinary tract infections.

Muscle organization in individuals with and without pain and joint dysfunction

Central nervous system organization of masticatory muscles determines the magnitude of joint and muscle forces. Validated computer-assisted models of neuromuscular organization during biting were used to determine organization in individuals with and without temporomandibular disorders (TMD). Ninety-one individuals (47 women, 44 men) were assigned to one of four diagnostic groups based on the presence (+) or absence (-) of pain (P) and bilateral temporomandibular joint disc displacement (DD). Electromyography and bite-forces were measured during right and left incisor and molar biting. Two three-dimensional models employing neuromuscular objectives of minimization of joint loads (MJL) or muscle effort (MME) simulated biting tasks. Evaluations of diagnostic group and gender effects on choice of best-fit model were by analysis of variance (ANOVA) and Tukey-Kramer post hoc tests, evaluations of right-left symmetry were by Chi-square and Fisher's exact statistics, and evaluations of model accuracy were by within-subject linear regressions. MME was the best-fit during left molar biting in +DD individuals and incisor biting in men (all p < 0.03). Incisor biting symmetry in muscle organization was significantly higher (p < 0.03) in healthy individuals compared with those with TMD. Within-subject regressions showed that best-fit model errors were similar among groups: 8 to 15% (0.68 ≤ R(2) ≤ 0.74). These computer-assisted models predicted muscle organization during static biting in humans with and without TMDs.

Randomized multicenter clinical trial of myofascial physical therapy in women with interstitial cystitis/painful bladder syndrome and pelvic floor tenderness

PURPOSE

We determined the efficacy and safety of pelvic floor myofascial physical therapy compared to global therapeutic massage in women with newly symptomatic interstitial cystitis/painful bladder syndrome.

MATERIALS AND METHODS

A randomized controlled trial of 10 scheduled treatments of myofascial physical therapy vs global therapeutic massage was performed at 11 clinical centers in North America. We recruited women with interstitial cystitis/painful bladder syndrome with demonstrable pelvic floor tenderness on physical examination and a limitation of no more than 3 years' symptom duration. The primary outcome was the proportion of responders defined as moderately improved or markedly improved in overall symptoms compared to baseline on a 7-point global response assessment scale. Secondary outcomes included ratings for pain, urgency and frequency, the O'Leary-Sant IC Symptom and Problem Index, and reports of adverse events. We compared response rates between treatment arms using the exact conditional version of the Mantel-Haenszel test to control for clustering by clinical center. For secondary efficacy outcomes cross-sectional descriptive statistics and changes from baseline were calculated.

RESULTS

A total of 81 women randomized to the 2 treatment groups had similar symptoms at baseline. The global response assessment response rate was 26% in the global therapeutic massage group and 59% in the myofascial physical therapy group (p=0.0012). Pain, urgency and frequency ratings, and O'Leary-Sant IC Symptom and Problem Index decreased in both groups during followup, and were not significantly different between the groups. Pain was the most common adverse event, occurring at similar rates in both groups. No serious adverse events were reported.

CONCLUSIONS

A significantly higher proportion of women with interstitial cystitis/painful bladder syndrome responded to treatment with myofascial physical therapy than to global therapeutic massage. Myofascial physical therapy may be a beneficial therapy in women with this syndrome.

Reliability of electromyographic activity vs. bite-force from human masticatory muscles

The reproducibility of electromyographic (EMG) activity in relation to static bite-force from masticatory muscles for a given biting situation is largely unknown. Our aim was to evaluate the reliability of EMG activity in relation to static bite-force in humans. Eighty-four subjects produced five unilateral static bites of different forces at different biting positions on molars and incisors, at two separate sessions, and the surface EMG activities were recorded from temporalis, masseter, and suprahyoid muscles bilaterally. Intraclass correlation coefficients (ICCs) were determined, and an ICC of ≥ 0.60 indicated good reliability of these slopes. The ICCs for jaw-closing muscles during molar biting were: temporalis muscles, ipsilateral 0.58-0.93 and contralateral 0.88-0.91; and masseter muscles, ipsilateral 0.75-0.86 and contralateral 0.69-0.88. The ICCs for jaw-closing muscles during incisor biting were: temporalis muscles, ipsilateral 0.56-0.81 and contralateral 0.34-0.86; and masseter muscles, ipsilateral 0.65-0.78 and contralateral 0.59-0.80. For the suprahyoid muscles the 95% CIs were mostly wide and most included zero. The slopes of the EMG activity vs. bite-force for a given biting situation were reliable for temporalis and masseter muscles. These results support the use of these outcome measurements for the estimation and validation of mechanical models of the masticatory system.

Human temporomandibular joint eminence shape and load minimization

Analysis of previous data suggested the hypothesis that temporomandibular joint (TMJ) eminence shapes develop ideally to minimize joint loads. Hence, we tested this hypothesis in nine females and eight males in each of two groups, with and without TMJ disc displacement. Participants provided anatomical data used in a joint load minimization numerical model to predict, and jaw-tracking data used to measure, eminence shapes. Coordinate data (x,y) of shapes were fit to third-order polynomials for two sessions, sides, and methods (predicted, measured) for each participant. Inter-session data were reliable and averaged. Those with, compared with those without, disc displacement had higher measured shape range (5:1) and left-right asymmetry prevalence (4:1). In 29 symmetrical individuals, ANCOVA and Bonferroni tests compared vertical dimensions (y) at 11 postero-anterior points (x), 0.5 mm apart. Model-predicted and measured shapes were significantly different (P < or = 0.01) near the eminence crest, but joint load minimization was consistent with eminence shape for x < 3.0 mm.

A biphasic finite element model of in vitro plowing tests of the temporomandibular joint disc

Disorders of the temporomandibular joint (TMJ) afflict 3-29% of people aged 19-40 years. Degenerative joint disease (DJD) of the TMJ generally occurs 15 years earlier than in other human joints and 1.5-2 times more often in women than men. The TMJ disc is the primary stress distribution mechanism within the joint. Mechanical failure of the TMJ disc precedes clinical signs of DJD. Unlike postcranial synovial joints, biomimetic replacements of the disc have not been successful, probably due to the paucity of knowledge about TMJ biomechanics. Translation of stress-fields mediolaterally across the TMJ disc may lead to fatigue failure because of the effect of traction forces on the tissue surface and because the disc is relatively weak in this aspect. Traction forces are composed of friction forces, which are known to be low in the TMJ, and plowing forces which are relatively much higher and result from movement and pressurization of fluids within the tissues due to translating surface loads. In the in vitro plowing experiment, a rigid curve-ended indenter is lowered into a TMJ disc that has been mounted on a stage with pressure gauges, and the indenter is then translated in a prescribed mediolateral motion that is intended to simulate the motion of the mandibular condyle on the TMJ disc in vivo. As a first step, these plowing experiments have quantified the variables thought to be important in tissue failure. A next step is to define the full role of these variables in the pathomechanics of TMJ disc tissue through a validated model. Therefore, the aim of this study was to develop and test a finite element model of the plowing experiments based on an orthotropic biphasic description of the soft tissue behavior of the TMJ disc. For this plowing model, the arbitrary Lagrange Eulerian method was used to approximate the moving load problem, where in vitro the indenter slid along the tissue's superior surface. Approximate validation of the plowing model was based on comparisons of model-predicted temporal and spatial distribution of indenter displacement and total normal stresses (+/-15%) and laboratory measurements during one complete cycle of plowing motion. Other useful predictions from the plowing model include spatial and temporal distributions of biomechanical variables of interest that cannot be measured experimentally, such as total stress, pressure, strain, and the relative significance of the orthotropic solid phase properties.

A meta-analysis of the vascular-related safety profile and efficacy of alpha-adrenergic blockers for symptoms related to benign prostatic hyperplasia

OBJECTIVES

To evaluate the safety profile and efficacy of alpha1-adrenergic receptor blockers (A1Bs) currently prescribed for benign prostatic hyperplasia (BPH).

DATA SOURCES

A systematic literature search of MEDLINE, the Cochrane Database and the Food and Drug Administration Web site through December 2006 identified double-blinded, prospective, placebo-controlled trials, evaluating agents commercially available by prescription for the symptomatic treatment of BPH.

REVIEW METHODS

Data were reviewed by two investigators with the use of a standardised data abstraction form. Studies were evaluated for methodological quality using the Jadad scale. Studies with a score of < 3 were considered of weaker methodology.

RESULTS

Of 2389 potential citations, 25 were usable for evaluation of safety data, 26 for efficacy. A1B use was associated with a statistically significant increase in the odds of developing a vascular-related event [odds ratio (OR) 2.54; 95% confidence interval (CI): 2.00-3.24; p < 0.0001]. The odds of developing a vascular-related adverse event were: alfuzosin, OR 1.66, 95% CI: 1.17-2.36; terazosin, OR 3.71, 95% CI: 2.48-5.53; doxazosin, OR 3.32, 95% CI: 2.10-5.23 and tamsulosin, OR 1.42, 95% CI: 0.99-2.05. A1Bs increased Q(max) by 1.32 ml/min (95% CI: 1.07-1.57) compared with placebo. Difference from placebo in American Urological Association symptom index/International Prostate Symptom Score was -1.92 points (95% CI: -2.71 to -1.14).

CONCLUSIONS

Alfuzosin, terazosin and doxazosin showed a statistically significant increased risk of developing vascular-related events compared with placebo. Tamsulosin showed a numerical increase that was not statistically significant. All agents significantly improved Q(max) and symptom signs compared with placebo.

Clinical phenotyping in chronic prostatitis/chronic pelvic pain syndrome and interstitial cystitis: a management strategy for urologic chronic pelvic pain syndromes

The urologic chronic pain conditions such as chronic prostatitis/chronic pelvic pain syndrome and interstitial cystitis are syndromes whose evaluation and management are controversial. Part of the difficulty in diagnosis and therapy is the heterogeneity of etiologies and symptoms. We propose a six-domain phenotype, which can classify these patients clinically and can direct the selection of therapy in the most evidence based multimodal manner. The domains are urinary, psychosocial, organ specific, infection, neurologic and tenderness of skeletal muscles. This system is flexible and responsive to new biomarkers and therapies as their utility and efficacy are proven.

Mechanical work during stress-field translation in the human TMJ

The pathomechanics of degenerative joint disease of the temporomandibular joint (TMJ) may involve fatigue produced by mechanical work on the articulating tissues. This study tested the hypotheses that mechanical work in the TMJ (i) varies with the type of mandibular activity, and (ii) is evenly distributed over TMJ surfaces. Ten healthy human participants were recorded with Magnetic Resonance Imaging (MRI) and jaw tracking. The data were used to reconstruct and animate TMJ activity. Aspect ratios, instantaneous velocities, and distances of stress-fields translation were used to calculate work (mJ). The results were analyzed by least-squares polynomial regression and ANOVA. Work magnitudes were related to peak velocity (R(2) = 0.92) and distance of stress-field translation (R(2) = 0.83), and were distributed over the joint surfaces (p < 0.03). During mandibular laterotrusion, average mechanical work was 1.5 times greater in the contralateral joint. Peak magnitudes of work (> 3000 mJ) were 4 times that previously reported.

Static and dynamic loading effects on temporomandibular joint disc tractional forces

Mechanical fatigue-related degeneration of the temporomandibular joint (TMJ) disc may be promoted by tractional forces. This study tested the hypotheses that tractional forces following static loading of the TMJ disc: (1) increase with compressive strain at the start of movement, and (2) are velocity-dependent during movement. Sixty-four porcine discs received a 10-N static load via an acrylic indenter for 1 or 30 sec before cyclic movement. Physical data were recorded and analyzed by ANOVA. The results showed that compressive strain and tractional forces were largest for the start of movement following 30 sec of static loading (p <or= 0.0001) and were correlated (R(2) = 0.84). Peak tractional forces were linearly and positively related to velocity of movement (R(2) = 0.85), and were highest during Cycle 1 after 30 sec of loading (p <or= 0.0067). The results demonstrated that tractional forces were strain-related at the start of movement and velocity-dependent during movement.

ABBREVIATIONS

ANOVA = analysis of variance, PBS = phosphate-buffered physiological saline solution, TMJ = temporomandibular joint, mu(T) =tractional coefficient, mu(s) = static coefficient of friction.

Responsiveness of the National Institutes of Health Chronic Prostatitis Symptom Index (NIH-CPSI)

OBJECTIVES

The NIH-Chronic Prostatitis Symptom Index (NIH-CPSI) was developed to assess symptoms and quality of life in men with chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS). We assessed the responsiveness of the NIH-CPSI to change over time and defined thresholds for changes perceptible to patients.

METHODS

We studied 174 men with CP/CPPS who participated in a placebo-controlled randomized clinical trial. Changes from baseline to six weeks in the NIH-CPSI total score and pain, urinary, and quality of life subscores were compared to a global response assessment (GRA). Effect sizes and Guyatt statistics were calculated to evaluate responsiveness; 95% confidence intervals were produced using bootstrapping.

RESULTS

All scores decreased over time with the largest decrease in subjects who reported on the GRA that they were markedly improved. The NIH-CPSI total, pain, and quality of life scores were highly responsive in the improved groups; the urinary score showed minimal responsiveness. There was no evidence of responsiveness among those subjects who worsened on the trial. ROC curves identified a 6-point decline in the NIH-CPSI total score as the optimal threshold to predict treatment response.

CONCLUSIONS

The NIH-CPSI total score and pain and quality of life subscores are responsive to change over time.

Triplet superconducting pairing and density-wave instabilities in organic conductors

Using a renormalization group approach, we determine the phase diagram of an extended quasi-one-dimensional electron gas model that includes interchain hopping, nesting deviations, and both intrachain and interchain repulsive interactions. We find a close proximity of spin-density- and charge-density-wave phases and singlet d-wave and triplet f-wave superconducting phases. There is a striking correspondence between our results and recent puzzling experimental findings in the Bechgaard salts, including the coexistence of spin-density-wave and charge-density-wave phases and the possibility of a triplet pairing in the superconducting phase.

French-Canadian linguistic validation of the NIH Chronic Prostatitis Symptom Index

INTRODUCTION

The NIH Chronic Prostatitis Symptom Index (CPSI) is recommended in the clinical evaluation of men with chronic prostatitis/chronic pelvic pain syndrome (CP/CPPS). However, its use is not possible in French speakers, as it has not been validated in this population. We performed a linguistic validation of the CPSI.

METHODS

Linguistic translation followed the forward-backward-forward technique and relied on professional medical translators, bilingual health professionals, and patient input. Along with the SF-12, the translated version was administered to a convenience sample of men presenting for pre-vasectomy visits (controls) and to consecutive patients with established CP/CPPS (cases). Men with CP/CPPS were subsequently asked to complete a 14-day retest questionnaire. Psychometric testing addressed standard reliability and validity characteristics.

RESULTS

Thirty-six cases and 38 controls with respective mean ages of 46.5 and 44.0 years participated and 33 (91.2%) cases completed the retest questionnaire. Pain (p<0.001), urinary (p<0.001) and quality-of-life (QOL) scale (p<0.001) score means differed between cases and controls. For the same scales, Cronbach's alphas for cases were respectively 0.70, 0.72 and 0.79 versus 0.80, 0.57, and 0.88 for controls. The retest product-moments were 0.83 for pain, 0.55 for urinary, and 0.83 for QOL scales. In cases, strong correlation was noted between QOL and pain scales (r=0.7), and between urinary and pain scales (r=0.6), versus moderate correlation between QOL and urinary scales (r=0.4). Negative correlation was recorded between CPSI scales and SF-12 scales, which ranged from -0.2 to -0.4.

CONCLUSIONS

When applied to CPPS and control subjects, the French Canadian CPSI translation demonstrates excellent discriminant properties. Moreover, its reliability and validity characteristics confirm the qualities of the CPSI as a standard evaluative tool for men with CPPS.

A randomized placebo-controlled multicentre study to evaluate the safety and efficacy of finasteride for male chronic pelvic pain syndrome (category IIIA chronic nonbacterial prostatitis)

OBJECTIVE

To determine if finasteride can reduce symptoms in men with a clinical diagnosis of chronic nonbacterial prostatitis (National Institutes of Health, NIH, category IIIA chronic pelvic pain syndrome, CPPS) compared with placebo.

PATIENTS AND METHODS

Men (76) with category IIIA CPPS enrolled in four North American prostatitis research centres were randomized after a 2-week placebo run-in to finasteride or placebo for 6 months. The primary efficacy variable was a subjective overall assessment (SOA); the secondary efficacy variables included the NIH chronic prostatitis symptom index (NIH-CPSI) and safety data. Patients were assessed at screening, baseline (after the 2-week placebo run-in), 3 and 6 months.

RESULTS

Sixty-four patients had at least one assessment on medication (31 placebo, 33 finasteride); 75% of the finasteride and 54% of the placebo group had at least a mild improvement (defined as > 25% improvement in SOA), and 44% and 27%, respectively, a moderate or marked improvement (>50% improvement in SOA). The trend was similar in the NIH-CPSI scores. Five patients in the finasteride and seven in the placebo group reported medication-related adverse events.

CONCLUSION

This randomized placebo-controlled pilot study suggests that finasteride was of benefit for some men with category IIIA CPPS, but the results do not justify recommending finasteride as monotherapy, except for men who also have benign prostatic hyperplasia. A larger, properly powered study, possibly evaluating combination with other therapies or specifically in men with prostatitis and benign prostatic hyperplasia, is required to confirm any clinical benefit.

Prevalence, diagnosis and treatment of prostatitis in Italy: a prospective urology outpatient practice study

OBJECTIVE

To report a prospective, multicentre descriptive study designed to determine the prevalence of the diagnosis of prostatitis in male outpatients examined by urologists in Italy, and to further examine the diagnostic evaluation and treatment of patients identified with a clinical diagnosis of prostatitis.

PATIENTS AND METHODS

Between July 2001 and October 2001, 70 urologists, representing a cross-section of urological centres in Italy, counted and recorded the overall total of men reported in the clinic and that of patients diagnosed with prostatitis over a 5-week period. Data on demographics, previous diagnoses, symptoms, physical examination, laboratory data and therapy instituted were collected. Patients with a diagnosis of prostatitis completed questionnaires on symptom frequency and severity, and quality of life.

RESULTS

In all, 8503 patients were included in the primary outcome analysis; 1148 were identified with prostatitis (12.8%; mean age 47.1 years, range 16-83) with all age ranges equally represented, and 68% had had their first symptom within the last year. The most common presenting symptoms were severe, bothersome urinary frequency, obstructive voiding symptoms, perineal, suprapubic and penile pain or discomfort. The self-administered questionnaire confirmed that the most frequently reported and most severe symptoms at the time of evaluation were irritative voiding symptoms, perineal and suprapubic pain and discomfort. Over three-quarters of the patients were dissatisfied with their quality of life. While 98% of the patients had a digital rectal examination and expressed prostatic secretion was successfully recovered in 44%, < 3% of the patients had the traditional Meares-Stamey four-glass test. The most common treatment prescribed was drug therapy (not antibiotic).

CONCLUSION

The prevalence of a clinical diagnosis of prostatitis in urology outpatient practice in Italy was 12.8%. The prevalence, diagnosis, evaluation and treatment of prostatitis reported in this prospective study was very similar to that reported in other retrospective series from other countries.

Neuromuscular objectives of the human masticatory apparatus during static biting

OBJECTIVE

The central nervous system controls the muscles of mastication and may dictate muscle outputs according to a biologically important objective. This study tested the hypotheses that (a) the effective sagittal TMJ eminence morphology, and (b) the outputs of the masticatory muscles during static biting, are consistent with minimisation of joint loads or minimisation of muscle effort.

DESIGN

Numerical modelling predicted effective eminence morphology (from sagittal plane directions of TMJ force for centred loading over a range from molar to incisor biting) and TMJ and muscle forces during static unilateral biting in seven subjects. In vivo effective eminence morphology was measured from jaw tracking recorded from each subject. Muscle activities during biting tasks on first molar and incisor teeth were measured by electromyography using surface or indwelling electrodes.

RESULTS

Subject-specific predicted effective eminence morphology correlated with in vivo data (0.85< or =R2< or =0.99). Mixed and random coefficient analysis of covariance indicated good agreement between predicted and measured muscle outputs for all muscles of mastication investigated. Individual linear regression analysis showed that modelled muscle outputs accurately predicted EMG data, with average errors of 8% for molar and 15% for incisor biting.

CONCLUSIONS

Effective sagittal eminence morphology was consistent with minimisation of joint loads for all subjects. Masticatory muscle outputs during unilateral biting were consistent with minimisation of joint loads or minimisation of muscle effort, or both, depending on the subject. These results are believed to be the first to test model predictions of muscle output during biting for all muscles of mastication.

Classification and diagnosis of prostatitis: a gold standard?

The National Institutes of Health Classification System for prostatitis has now been accepted by the North American and International urology community. This categorization system consists of category I (acute bacterial prostatitis), category II (chronic bacterial prostatitis), category III (chronic prostatitis/chronic pelvic pain syndrome - CP/CPPS) and category IV asymptomatic inflammatory prostatitis. The evaluation of a patient with category I and category II bacterial prostatitis consists of history and physical examination and urine culture for lower urinary tract localization cultures, respectively. The clinical tests for the evaluation of CP/CPPS can be classified as mandatory, recommended and optional. Mandatory evaluations include history and physical examination, urinalysis and urine culture. Recommended evaluations include lower urinary tract localization tests, symptom index, flow rate, residual urine determination and urine cytology. Optional evaluations include semen analysis and culture, urethral swab, urodynamics, cystoscopy, imaging, and prostate specific antigen determination. The physician must individualize a rational diagnostic strategy for each patient. There is no 'gold standard' for the diagnosis and evaluation of patients presenting with prostatitis.

Human masticatory muscle forces during static biting

Muscle forces determine joint loads, but the objectives governing the mix of muscle forces involved are unknown. This study tested the hypothesis that masticatory muscle forces exerted during static biting are consistent with objectives of minimization of joint loads (MJL) or muscle effort (MME). To do this, we compared numerical model predictions with data measured from six subjects. Biting tasks which produced moments on molar and incisor teeth were modeled based on MJL or MME. The slope of predicted vs. electromyographic (EMG) data for an individual was compared with a perfect match slope of 1.00. Predictions based on MME matched best with EMG activity for molar biting (slopes, 0.89-1.16). Predictions from either or both models matched EMG results for incisor biting (best-match slopes, 0.95-1.07). Muscle forces during isometric biting appear to be consistent with objectives of MJL or MME, depending on the individual, biting location, and moment.

Prostatitis-like symptoms: one year later

OBJECTIVES

To re-survey (after 1 year) men identified in 1999 as having perineal and/or ejaculatory pain/discomfort severe enough to suggest a clinical diagnosis of chronic prostatitis (using the National Institutes of Health-Chronic Prostatitis Symptom Index, NIH-CPSI), and to compare them with an age-matched population of men who had no prostatitis-like symptoms in the initial survey, to determine the effect of time on specific symptoms associated with the diagnosis of chronic prostatitis.

SUBJECTS AND METHODS

A comprehensive questionnaire incorporating the pain and voiding domains of the NIH-CPSI, and data on demographics, medical history, socio-economic status, health-seeking behaviour and a quality of life assessment, was sent to 67 men who had reported prostatitis-like symptoms in the 1999 survey, and to 202 age-matched controls (1 : 3) who reported no prostatitis-like symptoms in the same survey.

RESULTS

Forty men (60%) with previous prostatitis-like symptoms, i.e. a mean (sd) 1999 NIH-CPSI pain score of 8.8 (0.4), and 119 (59%) of the control population completed and returned the survey. There was no difference in the 1999 demographics (P = 0.82) or NIH-CPSI pain score (P = 0.49) between patients who returned the recent questionnaire and those who could not be located or declined to complete the survey. Fifteen men (38%) identified with prostatitis in 1999 did not report similar symptoms in 2000. The initial mean NIH-CPSI pain score (0-21) for the men who had resolution of their prostatitis-like symptoms was 7.5 (0.6); 1 year later it was 0.73 (0.3). Their mean age was 51.1 (3.9) years and mean duration of symptoms 1.1 (0.3) years. Those with persistent symptoms had an initial NIH-CPSI pain score of 9.6 (0.5); 1 year later it was 8.68 (0.4), at mean age of 51.4 (2.5) years and duration of symptoms 2.2 (0.3) years. Four men (3%) in the control group who had no symptoms in 1999 reported prostatitis-like symptoms in 2000; these men had a mean age of 52.5 (5.9) and NIH-CPSI pain score of 7.0 (0.9).

CONCLUSION

About a third of men reporting prostatitis-like symptoms in the general population had resolution of their symptoms (usually those with a shorter duration and less severe symptoms) 1 year later. The severity of symptoms of men with persistent chronic prostatitis remained relatively unchanged over the year.

The urologist view of BPH progression: results of an international survey

OBJECTIVES

To assess the opinion amongst the international urological community on whether benign prostatic hyperplasia (BPH) is a progressive disease.

METHODS

A 15-item questionnaire was distributed to the mailing list of the publication European Urology Today as well as being accessed through the website of the European Association of Urology (EAU). The survey included questions on: whether BPH was a progressive disorder; what evidence there was to support this, including clinical parameters that could be identified; risk factors for progression; and prevention of progression.

RESULTS

A total of 472 completed questionnaires from 47 countries were evaluated. Overall, the urologists surveyed agreed that BPH was a progressive disease, and that some patients were more prone to this than others. Increased post-void residual urine, reduced flow rate, increased urinary symptoms and urodynamic evidence of obstruction were considered to be the most significant risk factors for progression. Half of the urologists surveyed considered that current medical therapies could prevent progression of BPH, while a significant proportion thought that surgery was an effective preventative measure.

CONCLUSIONS

BPH, although a benign disease, has a considerable impact on the patient's quality of life. Its progressive nature and the identification of risk factors for progression warrant further investigation. In the future, there is likely to be a shift in the paradigm from treatment of BPH complications to include the prevention of BPH progression.

Strain rate dependent orthotropic properties of pristine and impulsively loaded porcine temporomandibular joint disk

The purpose of this study was to characterize the tensile stress-strain behavior of the porcine temporomandibular joint (TMJ) disk with respect to collagen orientation and strain rate dependency. The apparent elastic modulus, ultimate tensile strength, and strain at maximum stress were measured at three elongation rates (0.5, 50, and 500 mm/min) for dumbbell-shaped samples oriented along either anteroposterior or mediolateral axes of the disks. In order to study the effects of impact-induced fissuring on the mechanical behavior, the same properties were measured along each orientation at an elongation rate of 500 mm/min for disks subjected to impulsive loads of 0.5 N. s. The results suggested a strongly orthotropic nature to the healthy pristine disk. The values for the apparent modulus and ultimate strength were 10-fold higher along the anteroposterior axis (p < or = 0.01), which represented the primary orientation of the collagen fibers. Strain rate dependency was evident for loading along the anteroposterior axis but not along the mediolateral axis. No significant differences in any property were noted between pristine and impulsively loaded disks for either orientation (p > 0.05). The results demonstrated the importance of choosing an orthotropic model for the TMJ disk to conduct finite element modeling, to develop failure criteria, and to construct tissue-engineered replacements. Impact-induced fissuring requires further study to determine if the TMJ disk is orthotropic with respect to fatigue.

Absorption of alkalized intravesical lidocaine in normal and inflamed bladders: a simple method for improving bladder anesthesia

PURPOSE

Pharmacokinetic studies have shown that intravesical lidocaine is not sufficiently absorbed by human bladders to achieve significant serum levels and it only provides a superficial local anesthetic effect. We investigated the pharmacokinetics of alkalized intravesical lidocaine in healthy volunteers and patients with interstitial cystitis to determine a safe dose of buffered lidocaine, the effect of interstitial cystitis on lidocaine uptake and the acute local anesthetic effect on bladder pain in interstitial cystitis.

MATERIALS AND METHODS

An initial dose finding study was done in 12 healthy volunteers using 4, 5 and 6 mg./kg. 5% lidocaine buffered with 8.4% sodium bicarbonate. Serial lidocaine levels were measured for 3 hours. Serum measurement was repeated in 12 patients with interstitial cystitis using 5 mg/kg. 5% lidocaine with sodium bicarbonate daily for 2 days. Patients rated pain before and during treatment.

RESULTS

Healthy volunteers and patients with interstitial cystitis had similar lidocaine absorption profiles with a peak of 1.06 microg/ml. (range 0.66 to 1.71) and 1.3 (range 0.2 to 2.0) at about 30 minutes. Mean pain score in the interstitial cystitis group decreased from a baseline of 6.0 to 1.8 on day 1 and 0.6 on day 2. There were complaints of urethral discomfort after voiding the buffered lidocaine in each group.

CONCLUSIONS

Alkalization provides safe and predictable lidocaine absorption into the bladder, as indicated by therapeutic systemic levels in healthy and inflamed bladders. Furthermore, the decrease in acute pain scores in the interstitial cystitis group indicated a concentration of local anesthetic within the bladder wall that was sufficient to block the sensory neurons within the submucosal plexus.

Impact of medical therapy on transurethral resection of the prostate: a decade of change

OBJECTIVES

To assess whether medical therapy has delayed the need for eventual transurethral prostatectomy (TURP), causing a shift in the population characteristics of men undergoing TURP (ie, older, more comorbidities, more advanced disease), resulting in more complications and poorer outcomes. The introduction of medical therapy for symptomatic benign prostatic hyperplasia (BPH) during the past decade may have changed the indications for TURP.

METHODS

All patients who underwent TURP for symptomatic BPH at our institution in 1988 (before general introduction of medical therapy for BPH) and 1998 (medical therapy the primary initial therapy for BPH) were reviewed. We compared the two groups with respect to the total number of TURPs, indications for surgery, patient age, health status, weight of resected tissue, and preoperative and postoperative complications.

RESULTS

Despite a 16% increase in men at risk of BPH-related events, a 60% decrease in the total number of TURPs performed for symptomatic BPH occurred in 1998 (n = 64) compared with 10 years earlier (n = 157). No significant difference was found in age between the two groups, and no increase in comorbid status was observed. Previous medical management had failed in 36% of men who required TURP in 1998. A significantly higher percentage of patients presented in acute urinary retention (55%) and upper tract obstructive uropathy (12.5%) in 1998 compared with 1988 (23% acute urinary retention and 1.3% obstructive uropathy). Patients in 1998 were healthier, underwent smaller resections, had their catheters removed earlier, and were discharged home earlier. Although they were more likely to be discharged home with a catheter in situ, no significant difference was observed in the incidence of postoperative complications.

CONCLUSIONS

There has been a dramatic decrease in the number of TURPs performed for symptomatic BPH at our institution since the advent of medical therapy. The proportion of TURP patients presenting with urinary retention and hydronephrosis increased, but the average age, medical comorbidities, operative parameters, and postoperative complications have not significantly changed.

Consensus development of a histopathological classification system for chronic prostatic inflammation

OBJECTIVE

To develop a standardized histopathological classification system for chronic prostatitis (standardized description of prostatic inflammatory infiltrates) based on a literature review, extensive prospective evaluations in two recognized prostatitis research centres and widespread consensus of international urological centres identified as having major expertise or interest in chronic prostatitis.

METHODS

Relevant articles for review were identified by a Medline search undertaken by the Cochrane Review Group in Prostate Diseases and Urologic Malignancies, and cross-checking bibliographies of retrieved studies, reviews, book chapters and abstracts of the American Urological Association and International Prostatitis Collaborative Network Annual Meetings. Initial drafts were based on classification systems independently developed by the Prostatitis Research Centers at Queen's University in Canada and University of Washington in the USA. A collaborative draft was distributed to 20 urological/pathological clinical centres who participated in the North American Chronic Prostatitis Collaborative Research Network and First International Prostatitis Collaborative Network. A consensus classification system was then distributed to the participating panel for acceptance.

RESULTS

The literature review identified a reasonably consistent description of inflammatory infiltrate locations and patterns that were further incorporated into the draft based on the Queen's University and University of Washington proposals. Eighteen (90%) of the identified Prostatitis Centers participated in the revision of the draft and the final consensus process. The final consensus document classifies prostatic inflammation according to its extent and grade/severity in each tissue compartment (location). Conclusion The consensus of the expert panel was that this classification system can be used in the evaluation of prostatic inflammation in prostate biopsies, transurethral resected prostate chips or prostatectomy specimens. A standardized accepted framework to describe histopathological prostate inflammation will prove useful in evaluating prostate disease.

The management of acute pyelonephritis in adults

Acute pyelonephritis should be classified clinically at the time of presentation into either uncomplicated or complicated categories. The diagnostic workup includes history, physical examination, urinalysis (including a Gram stain), and urine culture. Patients with suspected complicated pyelonephritis require the standard assessment plus blood cultures and urinary tract imaging, preferably a computed tomography (CT) scan. Patients with moderate, uncomplicated pyelonephritis can be managed as outpatients with either a fluoroquinolone (7-14 days) or trimethoprim/sulfamethoxazole (at least 14 days). Patients with severe, uncomplicated pyelonephritis can be considered for short-term hospitalization and initial administration of intravenous antibiotics. Therapy for patients with complicated pyelonephritis should include initial hospitalization, supportive therapies, administration of wide spectrum intravenous antibiotic therapy, and relief of aggravating conditions. Such maneuvers could consist of simple bladder catheterization, percutaneous nephrostomy drainage, or definitive surgery. Patients with complicated pyelonephritis require longer duration of culture-specific antibiotic dosing, careful monitoring, long-term follow-up, and possible definitive management of their underlying condition.

Predictors of patient response to antibiotic therapy for the chronic prostatitis/chronic pelvic pain syndrome: a prospective multicenter clinical trial

PURPOSE

To our knowledge antibiotics are the most popular choice of therapy for all categories of the chronic prostatitis/chronic pelvic pain syndrome. We determine if culture, leukocyte and/or antibody status of prostate specific specimens predicts patient response to antibiotic therapy.

MATERIALS AND METHODS

Patients clinically diagnosed with the chronic prostatitis/chronic pelvic pain syndrome according to the National Institutes of Health (NIH) definition had a lower urinary tract evaluation that included standard microscopy and culture of prostate specific specimens, and determination of the ratio of voided bladder 3 and voided bladder 2 antibody levels against a panel of identified prostate pathogens (enzyme linked immunosorbent assay methodology). Symptom evaluation consisted of the NIH chronic prostatitis symptom index (derived) pain scale 0 to 21, symptom severity index scale 0 to 100, symptom frequency questionnaire scale 0 to 50 and quality of life scale 0 to 6. Patients were stratified according to microscopy, culture and immune status, were treated with 12 weeks of ofloxacin, and were assessed at 4, 12 and 24 weeks with symptom scores as well as global assessments.

RESULTS

Based on leukocyte and culture results, 102 evaluable patients were stratified into categories II (14%), IIIA (48%) and IIIB (38%) of the chronic prostatitis/chronic pelvic pain syndrome. Of the cases 23% were categorized as antibody positive and 77% as antibody negative. Average age was 42 +/- 10 years and 92% of patients were white. Of the patients 57% believed that they had moderate to marked improvement. All categories of the chronic prostatitis/chronic pelvic pain syndrome and patients in whom antibody was positive or negative had significant improvement in the NIH chronic prostatitis symptom index, symptom severity index, symptom frequency questionnaire and quality of life scores compared with baseline (p <0.001). There was no significant difference in patient response to the stratification based on culture, leukocyte, that is categories II, IIIA and IIIB had same beneficial response, or antibody status.

CONCLUSIONS

Culture, leukocyte and antibody status of prostate specific specimens does not predict antibiotic response in patients with the chronic prostatitis/chronic pelvic pain syndrome. The perceived beneficial effect of antibiotics needs to be evaluated in a randomized placebo controlled trial.