The goal is to investigate the effect of a single-port R3 sympathicotomy on microvascular circulation in the affected fingers. This effect is analysed by performing cooling plethysmography and nailfold capillary microscopy bilaterally, following a unilateral, single-port thoracoscopic sympathicotomy.

Raynaud's phenomenon is discoloration, discomfort and numbness or pain in the fingers and toes as a result of excessively reduced blood flow due to sympathetic induced vasospasms, in response to a change in temperature or emotional stress. It usually affects multiple fingers of both hands and comes in frequent attacks, with little or no discomfort in between them. Current treatment consists of stepped-care, including preventive measures optimizing digital blood flow, oral and intravenous medical therapy aimed at improving microvascular circulation, surgical neuromodulation to achieve vasodilatation and neurostimulation.

While surgical sympathectomy is an established treatment of Raynaud's phenomenon, its more invasive nature has prevented widespread application as an initial therapy. After introduction of minimally invasive surgical techniques in recent years, the investigators have further optimized the endoscopic sympathicotomy procedure performed on hyperhidrosis patients, now needing only a single 1 cm port for a detailed, panoramic view of the sympathetic chain (1). This minimal invasive technique has proven to be a safe, efficient and reproducible treatment for several indications and seems also suitable for Raynaud's patients.

In this feasibility study, the researchers want to investigate the effect of a single-port R3 sympathicotomy on microvascular circulation in the affected fingers. This effect is analysed by performing cooling plethysmography and nailfold capillary microscopy bilaterally, following a unilateral, single-port thoracoscopic sympathicotomy.

Inclusion Criteria:

• Severe form of SRP, defined as clinical need of prostacyclin analogue infusions and/or bosentan having been given in the preceding 2 years, without satisfying result.
• No concurrent neurological disease

Exclusion Criteria:

• Known Chronic Obstructive Pulmonary Disease > Gold class 1.
• History of smoking > 20 pack years, due to higher risk of complications following unilateral lung- deflation and re-insufflation.
• Documented substance addiction.
• Signs/symptoms of macrovascular disease, or abnormalities on Doppler/duplex studies
• Other signs/symptoms of systemic autoimmune disease
• Severe concomitant diseases of the liver (eg Liver Function tests > three times the upper limit of normal), kidneys (creatinine > 160 mol/l), heart (including history of myocardial infarction, heart failure or angina pectoris), lung, blood, endocrine system, gastrointestinal system, Central Nervous System.
• Previous intra-thoracic pleural drainage.
• Previous thoracic surgery (including sternotomy).
• Gross pulmonary or pleural abnormalities on chest X-ray.
• Pregnancy.
• Unsuitable anatomy (e.g. due to severe physical malformations).