STRUCTURAL BASIS OF GERIATRIC VOIDING DYSFUNCTION .1. METHODS OF A PROSPECTIVE ULTRASTRUCTURAL URODYNAMIC STUDY AND AN OVERVIEW OF THE FINDINGS

Voiding dysfunctions are common in the elderly. Yet the pathogenesis a nd pathophysiology have remained largely unknown. To date there has be en little information on structure of the aging detrusor. To gain insi ght into the structural basis of voiding dysfunction in the elderly, w e examined detrusor biopsy specimens by electron microscopy. The speci mens were obtained from 24 women and 11 men 65 to 96 years old (mean a ge 79 years) who were carefully selected by detailed clinical and neur ological examination. Symptom-free subjects were particularly sought t o identify those who might provide the structural/functional norm of a ging detrusor. Comprehensive urodynamic study was performed in all sub jects. A transurethral detrusor biopsy was obtained and processed to s tudy ultrastructure of the smooth muscle, intrinsic nerves and interst itium. Subjects were segregated purely by urodynamic findings, regardl ess of symptoms, into detrusor overactivity, outlet obstruction, obstr uction plus overactivity and neither (that is no obstruction and no ov eractivity) groups, each with a subgroup of normal and another of impa ired contractility. Specimens were segregated blindly and independentl y by ultrastructural features into dysjunction, myohypertrophy, myohyp ertrophy plus dysjunction and dense band patterns, each with a subset with widespread degeneration of muscle cells and nerves, and another w ith minimal or no degeneration. When codes were broken, each structura l pattern (and subset) matched with a specific urodynamic group (and s ubgroup)-with no overlap. The dysjunction pattern matched with overact ivity, the myohypertrophy pattern with obstruction, the myohypertrophy plus dysjunction pattern with obstruction plus overactivity, and the dense band pattern with the neither group. Structural subsets of wides pread degeneration matched with impaired contractility subgroups, and subsets with minimal or no degeneration matched with normal contractil ity subgroups. These observations identify specific structural bases o f the major forms of geriatric voiding dysfunction, provide important insights into their pathogenesis, and introduce detrusor biopsy as a p otentially valuable tool in their diagnosis and clinical management.