Please select the eligibility criteria that correspond to the clinical trial below.
Title: Comparison of Effectiveness of Tonic, High Frequency and Burst Spinal Cord Stimulation in Chronic Pain Syndromes: a Double-blind, Randomised, Cross-over, Placebo Controlled Trial
Brief Summary: Spinal cord stimulation (SCS) is one of the most commonly undertaken neuromodulatory surgery techniques in the treatment of neuropathic pain. The indication for SCS is an ineffective conservative treatment of chronic pain syndromes. The effectiveness of SCS in the case of neuropathic pain is high. The positive result of SCS treatment is the reduction of previous painful symptoms by min. 50% and / or a reduction in the amount of taken analgesics and an improvement in the quality of life including sleep quality. Long-term studies estimate that in a properly selected group of patients more than 50% of patients achieve pain reduction by the required 50% and about 60% - 70% have an improvement in the quality of life and a reduction of pain.

The efficacy of SCS in different modes of stimulation is evaluated. Patients receive four different types of stimulation for 2-week period - not knowing what kind of stimulation it is. It is said that in one type of stimulation they would feel parestesias and in other three they would not. Patients are not informed that beside tonic, burst and high frequency stimulation, the fourth is an off stimulation to check for placebo effect. The test is double-blinded


Options:
A: Inclusion Criteria:

* signed informed consent
* treated with spinal cord stimulation
* stable pain relief achieved

Exclusion Criteria:

* failure to give informed consent
* unable to use or understand how to handle the equipment, PGIC,VAS score or EQ-5D questionnaires.
B: Inclusion Criteria:

1. FBSS, CRPS patients with neuropathic and mixed pain in low-back and/or legs refractory to conservative therapy
2. Chronic pain as a result of FBSS that exists for at least 6 months
3. ≥ 18 years of age
4. Written consent of the patient to participate in study procedures.

Exclusion Criteria:

1. Active malignancy
2. Addiction to any of the following: drugs, alcohol and/or medication
3. Evidence of an active disruptive psychiatric disorder or other known condition significant enough to impact perception of pain, compliance to intervention and/or ability to evaluate treatment outcome as determined by investigator
4. Local infection or other skin disorder at site of surgical incision
5. Pregnancy
C: Inclusion Criteria:

1. A diagnosis of primary or idiopathic erythromelalgia
2. Patients ≥18 years who have developed chronic pain that has remained refractory to medical treatment for ≥6 months.
3. Minimum pain intensity of 5/10 on a numeric rating scale NRS at baseline.
4. Successful two-week SCS testing period with tonic stimulation (≥2 points reduction in pain NRS from baseline). This means patients will experience paresthesia during the trial period of spinal cord stimulation.

Exclusion Criteria:

1. Coexisting conditions that would increase procedural risk (e.g., sepsis, coagulopathy).
2. History of laminectomy or posterior fusion at the thoracolumbar junction, where percutaneous electrode end tips are routinely placed.
3. Abnormal pain behavior and/or unresolved psychiatric illness.
4. Unresolved issues of secondary gain or inappropriate medication use.
5. Unfit for participation for any other reason as judged by the study physician.
D: Inclusion Criteria:

* Moderate-to-severe PDP in the lower limbs

  * The pain intended to treat has been present for more than 12 months
  * Previous treatment has been unsuccessful (insufficient pain relief and/or unacceptable side-effects) with drugs from the following drug categories:
  * Amitriptylin or an other tricyclic antidepressant and/or
  * Pregabalin (Lyrica®) or Gabapentin (Neurontin®) and/or
  * Duloxetine (Cymbalta®) and/or
  * Tramadol or strong opioids Patients were treated with 3 drugs from the above mentioned drug categories and followed the treatment algorithm for painful diabetic polyneuropathy according to Jensen. Starting dosage was based on individual patient characteristics. Each drug was tried for at least 3 weeks and dose was raised once, if possible. By insufficient pain relief and/or unacceptable side-effects, the drug treatment was stopped. Patients reached a steady state in medication use and it is not allowed to increase dosage during the study.
* Mean pain intensity during daytime and/or night time should be 5 or higher measured on a numeric rating scale (NRS). Pain during daytime will be scored 3 times per day during for 4 days according to Jensen.
* Patient's age is between 18 and 75 years.

Exclusion Criteria:

* The patient has had neuromodulation therapy during the month before the intake
* Neuropathic pain is most prevalent in the upper limbs (NRS\>3)
* Neuropathy or chronic pain of other origin than diabetes mellitus (NRS\> 3)
* Addiction: drugs, alcohol (\> 5E / day) and/or medication

  * Drugs: cocaine, heroine, marihuana.
  * Alcohol: wine, beer, liquor (max 5E / day)
  * Medication: benzodiazepines.
* Insufficient cooperation from the patient (little motivation, understanding or communication)
* Blood clotting disorder, when using 2 or more different kinds of anti coagulation
* Immune deficiency (HIV-positive, corticosteroids with a dose equivalent to \> prednisolone 10 mg, immunodepressive, etc.)
* Peripheral vascular disease without palpable peripheral pulses at both feet (inclusion is possible if pulses are absent, but ankle brachial index is between 0.7 and 1.2 in both feet)
* Active foot ulceration
* Life expectancy \< 1 year
* Pacemaker
* Local infection or other skin disorders at site of incision
* Psychiatric problems potentially interfering with cooperation in the study
* Pregnancy
* Severe cardiac or pulmonary failure (\> NYHA classification II)
* Unstable blood glucose control (change in HbA1c\>1,0% in three months prior to inclusion)

Answer: B