Sodium Channel Mutations in Patient With the Anterior Cutaneous Nerve Entrapment Syndrome (ACNES)

• Sodium channel mutation (Other): Mutation of the genes SCN9A and SCN10A, which encode for Sodium channel 1.7 and 1.8.

Primary outcomes

• Sodium Channel 1.7 and 1.8 mutation. [Blood samples for SCN analysis will be taken only once after obtaining informed consent. This is the start of the study. Outpatient discharge (free of pain or no treatment options) is end of study. Treatment period can be a couple of weeks or months.]: Number of SCN9A and SCN10A mutations. Each mutation will be classified following one of three classes; unknown pathogenicity, probable pathogenicity, and pathogen variant.

Secondary outcomes

• Correlation between mutations and known cause of ACNES. [Baseline data will be obtained during first outpatient visit, before start of the treatment. The first outpatient visit takes 30 minutes (standard of care).]: Patients are asked (standard of care) if there is a possible cause of the ACNES. Correlations between the causes of ACNES and any identified mutations will be examined.
• Correlation between mutations and pain score at start of treatment. [Baseline data will be obtained during first outpatient visit, before start of the treatment. The first outpatient visit takes 30 minutes (standard of care).]: Patients are asked (standard of care) about the average pain score following the 0-10 numeric rating scale (NRS) (0 = no pain, 10 worst possible pain). Correlations between the NRS pain score and found mutations will be examined.
• Correlation between mutations and treatment response. [Treatment response will be assessed after each treatment during the treatment period at our outpatient clinic, up to 6 weeks after treatment.]: Patients follow different treatments according standard of care for ACNES. Starting with trigger point injections with a local anesthetic, if this treatment is not sufficient, it is followed by Pulse Radiofrequency. When patients still experience pain after minimal invasive treatments, a surgical neurectomy is performed. Correlations between treatment outcome after the different treatment options and found mutations will be examined. Treatment is defined successful if the patient does not need additional treatment, has >50% pain reduction, or reduction of >4 NRS points.

Sex: All, ages: 18 Years to any

Inclusion Criteria:

In order to be eligible to participate in this study, a subject must be diagnosed with ACNES and receive treatment at our outpatient clinic. Additionally, subject has to meet one of the following criteria:

* Known to have a first- or second-degree relative with ACNES;
* Have more than one recurrence of ACNES after a pain free period or ACNES at multiple locations in the abdominal wall;
* Persistent pain after posterior neurectomy.

Exclusion Criteria:

* Inability to understand Dutch language.
* Known neuromuscular or neurodegenerative disease.

• Rudi Roumen, MD, PhD, Principal investigator, Maxima Medical Center