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Primary nocturnal enuresis / Urinary incontinence

Last update: 24/03/2023, Dr. Miguel B. Royo Salvador, Medical Board number 10389. Neurosurgeon y Neurologist.


The involuntary release of urine is a condition characterized by an impelling and sudden urge to urinate, but an inability to hold urine. This is an alteration during the bladder-filling phase that can occur alone (primary), as well as in numerous conditions (secondary).

Primary/Monosymptomatic Nocturnal Enuresis is defined as an involuntary, intermittent and repeated release of urine during sleep, due to the inability to control sphincters in children over 5 years of age, who have never been continent before.

On the other hand, urinary incontinence is defined as the involuntary release of urine in adults. Leakages can occur when sneezing, laughing, with exertion or physical exercise.

Different types of urinary incontinence are described:

  • Stress incontinence
  • Urge incontinence
  • Mixed incontinence
  • Overflow incontinence
  • Psychogenic incontinence
  • Neurological incontinence



To determine a diagnosis of Primary Nocturnal Enuresis in children, or Primary Urinary Incontinence in adults, urine leakages must be entirely involuntary and objectively demonstrable.

In order to confirm that the disorder is primary, exams must aim at identifying and ruling out secondary causes – such as a neurogenic bladder and spinal cord abnormalities, urinary infections, presence of posterior urethral valve in male infants and ectopic ureter in young girls – through:

  • Complete clinical history: in the medical antecedents, the doctor will assess concomitant conditions, such as neurological conditions or systemic conditions that affect the central nervous system, previous surgeries that may affect the urinary tract, abdomen and pelvis and the spine. The medication that the patient is taking will also be reviewed.
  • Physical examination: it will include a perianal sensitivity test.
  • Exams: blood test, X-rays (plain abdominal x-ray, intravenous urography and vesicoprostatic echography) and urodynamic testing, including urinalysis with urine density (in children with primary nocturnal enuresis, urodynamic and radiological testing are not necessary)

The Filum System® method, based on the scientific findings on the etiology of several conditions and on the observation of several cases diagnosed of Filum Disease with nocturnal enuresis or urinary incontinence, recommends that brain and spine MRIs be done, once the urine leakage has been confirmed to be primary (both in children and adults).

  • Through an MRI, it is possible to confirm the presence of signs indicating abnormal medullary traction, as a possible correlated alteration, visible in the neuroimaging.



The symptom of primary nocturnal enuresis or urinary incontinence is the involuntary release of urine during the patient’s sleep or during wakefulness respectively.

The quantity or density of the leakage, as well as the frequency, may vary in each case. The leakages may occur especially with efforts, such as coughing and sneezing, physical activities or sexual intercourse.



Urinary release occurs when the bladder pressure is greater than the urethral pressure. There are many theories on the origin of primary nocturnal enuresis or primary urinary incontinence in adults, although none of them is entirely conclusive.

Its main causes are

  • The developmental delay in the functional maturity of the central nervous system, which can generate a defective sleep arousal mechanism.
  • Genetic
  • Sleep disorders.
  • Psychological and behavioural disorders.
  • Low levels of anti-diuretic hormone (ADH) at night in children with primary nocturnal enuresis cause an overproduction of urine.


Risk factors

The main risk factors for this condition in general are:

  • Having suffered from nocturnal enuresis during childhood represents an important risk factor towards urinary incontinence in adulthood.
  • In adulthood it is more common in women.

Regarding the primary nocturnal enuresis in children, according to several studies it is most common in:

  • Children with chronic headache.
  • Children with attention deficit hyperactivity disorder (ADHD) that has not been treated.
  • Described cases and series of cases with an association of sleep apnoea and nocturnal enuresis. This association is fully demonstrated with secondary enuresis, but not yet with primary nocturnal enuresis.
  • Overactive bladder (OAB) has been proved to be associated with primary nocturnal enuresis.



Enuresis or urinary incontinence, both in children and adults, can generate a problem:

  • Hygienic: especially in children, it can involve skin rashes on the buttocks and in the genital area.
  • Psychological: it can cause feelings of personal humiliation, emotional reactions of insecurity, affective inhibition, sexual inhibition, anxiety, depression, which can lead to low self-esteem.
  • Social: it involves missing opportunities or isolation, as it affects the patient’s activities and participation into his/her social group.

For all this, the patient’s condition can get complicated due to the worsening of his/her quality of life..



There are measures that can help delay the onset of urinary incontinence, as well as prevent it:

  • Non-pharmacological measures: motivational therapy, alarm devices, bladder training, lifestyle changes, hypnotherapy, behavioural methods, etc.
  • Pharmacological measures in patients over 7 years of age: tricyclic antidepressants, anticholinergic medication, desmopressin, combination therapies.

SEspecially for adult patients, the following treatments can also be indicated:

  • Surgery.
  • Intermittent self-catheterization.
  • Intravaginal electrical stimulation.

– According to the Filum System®:

Patients with a diagnosis of Filum Disease often present primary nocturnal enuresis and/or urinary incontinence. For this reason, this phenomenon is being studied and we recommend that possible Filum Disease signs be checked in these patients, to allow the application of the indicated neurosurgical treatment.

In 1993, with the publication of Dr. Royo-Salvador’s doctoral thesis, a relation is established between the filum terminale-induced caudal traction of the entire nervous system and several conditions, including the Filum Disease, that are considered to be caused by this traction. Since then, a new treatment has been designed – an etiological treatment, or related to the cause – as by surgically sectioning the filum terminale, it is possible to eliminate the caudal medullary traction force that is responsible for the pathological mechanism.

In the sectioning of the filum terminale we apply a minimally invasive technique, that is usually indicated to be performed as soon as possible in all cases of Filum Disease, since it involves minimum risks and stops the progression of the disease.


Minimally invasive sectioning of the Filum Terminale according to the Filum System®



1. It eliminates the medullary traction caused by a too short or too tense ligament.

2. With ICSEB’s minimally invasive surgical technique, surgical time is 45 minutes. Few hours of hospitalization. Local anaesthesia. Short postoperative period with no limitations. No admission to the Intensive care unit. No blood transfusions.

3. Its application implies a 0% mortality rate, with no sequelae.

4. It improves symptoms and stops the progression of conditions associated with the Filum Disease.




  1. Carlos Rodrigo Gonzalo de Liria, Tratamiento de la Enuresis Nocturna, Vol. 23, núm. 2. 2012. ISSN 0213-7801
ISSN 1579-9441. Butlletí d’informació terapèutica del Departament de Salut de la Generalitat de Catalunya.
  2. Cendron M. Primary nocturnal enuresis: current. Am Fam Physician 1999 Mar 1;59(5):1205-14, 1219-20.
  3. Dharnidharka V. Primary nocturnal enuresis: Where do we stand today? Indian Pediatr 2000 Feb 7;37(2):135-140.
  4. M. B. Royo-Salvador (2014), “Filum System® Guía Breve”.
  5. Dr. Miguel B. Royo Salvador (1997), Nuevo tratamiento quirúrgico para la siringomielia, la escoliosis, la malformación de Arnold-Chiari, el kinking del tronco cerebral, el retroceso odontoideo, la impresión basilar y la platibasia idiopáticas (PDF). REV NEUROL; 25 (140): 523-530
  6. National Clinical Guideline Centre. Nocturnal enuresis: the management of bedwetting in children and young people. London (UK): National Institute for Health and Clinical Excellence (NICE); 2010 Oct. 43 p. (Clinical guideline; no.111).
  7. Skoog SJ, Stokes A, Turner KL. Oral desmopressin: a randomized double-blind placebo controlled study of effectiveness in children with primary nocturnal enuresis. J Urol 1997 Sep;158(3 Pt 2):1035-40.

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