Also known as
AUS fluid loss, AUS cuff fluid deficiency, hydraulic fluid deficiency in AUS, AUS system fluid depletion, insufficient cuff pressure (AUS)
Definition
Insufficient Fluid in Cuff (AUS) is a mechanical complication of the Artificial Urinary Sphincter device characterized by inadequate fluid volume within the urethral cuff component, resulting in suboptimal compression of the urethra and persistent urinary incontinence.¹ The Artificial Urinary Sphincter consists of three primary components: a fluid-filled cuff that encircles the urethra, a pressure-regulating balloon that maintains constant pressure, and a control pump placed in the scrotum.² When functioning properly, the cuff provides circumferential compression of the urethra to prevent involuntary urine leakage; however, fluid loss compromises this mechanism, leading to decreased urethral coaptation and recurrent incontinence.³ This condition may occur immediately following device activation or develop gradually over time due to system leakage, osmosis of the filling agent, or in conjunction with urethral atrophy.⁴
Clinical Context
Insufficient Fluid in Cuff (AUS) is primarily encountered in male patients who have undergone Artificial Urinary Sphincter implantation for stress urinary incontinence, most commonly following radical prostatectomy, radiation therapy, or other urologic procedures.¹ Diagnosis requires a comprehensive evaluation including physical examination to assess pump cycling, cystoscopy to differentiate from cuff erosion, and potentially cross-sectional imaging to evaluate fluid volume in the pressure-regulating balloon.³ Findings associated with insufficient fluid include inability to cycle the device and persistent urinary incontinence despite device activation.¹ Treatment typically involves surgical revision with identification and resolution of the faulty connection or replacement of the responsible component.¹ In cases where urethral atrophy coexists with insufficient fluid, options include downsizing the cuff, replacing the cuff in a new location, or transcorporal placement.³ Patients should be counseled that device malfunction over time is expected, with revision rates of approximately 30% by 10 years post-implant.⁴
