You will be shown a paragraph from a biomedical research article. Your task is to extract all drug combinations appearing in a specific sentence within in the paragraph. Each drug combination should be assigned to one of the following three categories:

- POS: Indicates a positive interaction between the drugs in the combination; for instance, drugs that have an additive or synergistic effect.
- NEG: Indicates a negative interaction between the drugs in the combination; for instance, combining these drugs might result in adverse side effects, or might reduce their efficacy.
- COMB: Indicates that the drugs are given in combination, but the type of interaction between the drugs cannot be determined based on the provided context.

Please format your answer as a json array. Each entry in the array should itself be an array formatted as [<drug_1>, <drug_2>, ..., <drug_n>, <category>] where <category> is one of the three categories listed above and <drug_1>, ..., <drug_n> are drug names copied verbatim from the input sentence. Different combinations may involve different numbers of drugs; in other words, the `n` in <drug_n> may vary.

As an example, the following output describes two extracted drug combinations; one between two drugs, and one between three drugs:

[["artesunate", "artemether", "COMB"], ["Nifedipine", "Labetalol", "Prazosin", "POS"]]

The paragraph and specific sentence are below. You should only extract relationships expressed in the specific sentence; the paragraph is provided for context.

In your output, return only the json array and no other text. If no drug combinations appear, return an empty array `[]`.

paragraph: Efficacy of combined treatment with medial branch radiofrequency neurotomy and steroid block in lumbar facet joint arthropathy. To evaluate the long-term efficacy of combined radiofrequency (RF) neurotomy and steroid nerve block in patients with lumbar facet joint arthropathy. ### Materials And Methods Combined RF neurotomy and steroid nerve block was performed in 34 patients with chronic paravertebral low back pain. The diagnosis was confirmed by comparative double diagnostic block of the medial branch with bupivacaine and lidocaine . Under fluoroscopy, RF thermal ablation of the medial branch was performed (at RF needle tip temperature 85°C for 90 seconds), three times for each target nerve. At the end of the procedure, 20 mg of methylprednisolone acetate (sustained-release preparation) was infiltrated on each ablated nerve. Outcome variable was the degree of improvement in pain using visual analog scale (VAS) and numerical rating scale (NRS). Improvement in the quality of life was assessed using the Roland-Morris (RM) questionnaire. The procedure was repeated in cases of unbearable pain (>5 VAS score). ### results Patients had a mean VAS score of 8.6 before the procedure. Thereafter, VAS score was 0.91 immediately after the procedure and 3.0, 2.8, 3.7, and 3.6 at 1 month, 2 months, 6 months, and 1 year. NRS showed pain relief after the procedure of 85%, 65%, 78%, 62%, and 59.5% at the same time points. RM score was 18 before the procedure, 7.6 at 6 months after the procedure, and 8.5 at 1 year after the procedure. No major complication was noted except local pain in all patients and numbness of the back in six patients after the procedure. ### conclusions Combined RF neurotomy and steroid nerve block produced substantial improvement in terms of long-term pain relief and quality of life.

sentence: The diagnosis was confirmed by comparative double diagnostic block of the medial branch with bupivacaine and lidocaine .
[["bupivacaine", "lidocaine", "COMB"]]