Abstract Urodynamic evaluation is frequently used in the follow-up of the treatment and diag- nosis of incontinence, which develops in connec- tion with a neurogenic or non-neurogenic reason. There is no identified serious complication during or after urodynamic evaluation, present in the literature up to date. Hematuria, due to the ure- thral catheter, the development of oedema in the urinary bladder wall and the development of uri- nary bladder spasm as a result of catheter irrita- tion, are some of the complications, which may occur. In this paper, twist and knot formation in the double lumen urethral catheter after cystom- etry of a patient with a hypocompliant urinary bladder, has been presented. Keywords Cystometry Æ Catheter Æ Knotting Æ Complication Introduction Urodynamic evaluation is frequently used in the follow-up of the treatment and diagnosis of incontinence, which develops in connection with a neurogenic or non-neurogenic reason. The aver- age investigation period changes according to the age of the patient, the pathology of the urinary bladder and the patient’s cooperation. There is no identified serious complication during or after urodynamic evaluation, present in the literature up to date. Hematuria, due to the urethral cath- eter, the development of oedema in the urinary bladder wall and the development of urinary bladder spasm as a result of catheter irritation, are some of the complications, which may occur [1]. In this paper, twist and knot formation in the double lumen urethral catheter after cystometry of a patient with a hypocompliant urinary blad- der, has been presented. Case report Frequent urination and incontinence of urine were the complaints of a 75-year-old female pa- tient applying to our outpatient clinic. Urgency to urinate, incontinence of urine occurring with a cough or sudden movement was described. There was no dysuria. A right nephrectomy history was present due to a nonfunctional right kidney. There was no specific outcome of the routine physical examination. In the pelvic examination; incontinence with valsalva in urine, grade 1 cysto- cele and minimal rectocele was determined. The A. Ayyıldız Æ E. Huri Æ B. Nuhog ˘lu Æ C. Germiyanog ˘lu Ministry of Health Ankara Training and Research Hospital, Second Urology Clinic, Ankara, Turkey A. Ayyıldız(&) Dikmen cad. 55. Sokak O ¨ zu ¨ mit sitesi, K Blok 8/35, Keklikpinari, Ankara, Turkey e-mail: urology52@gmail.com Int Urol Nephrol (2006) 38:527–529 DOI 10.1007/s11255-006-0090-6 123 ORIGINAL ARTICLE Unexpected complication after cystometry in the hypocompliant urinary bladder: formation of a knot in the double lumen urethral catheter—a case report Ali Ayyıldız Æ Emre Huri Æ Barıs ¸ Nuhog ˘lu Æ Cankon Germiyanog ˘lu Received: 5 November 2005 / Accepted: 30 March 2006 / Published online: 15 December 2006 Ó Springer Science+Business Media B.V. 2006