Continuous Sciatic Nerve Block vs Epidural Analgesia in Lower Limb Amputation for Postoperative Pain (Ampupain)

Continuous Sciatic Nerve Block vs Epidural Analgesia in Lower Limb Amputation for Prevention of Acute Postoperative Pain and Phantom Limb Pain: A Triple-blind Randomized Controlled Non-inferiority Clinical Trial.

Controlled clinical trial of two parallel groups, with random assignment 1:1, non-inferiority, blinded for the patient, for who administers the intervention and for who analyzes the data. 112 participants

Controlled clinical trial of two parallel groups, with random assignment 1:1, non-inferiority, blinded for the patient, for who administers the intervention and for who analyzes the data. 112 participants Outcomes: Primary: Numeric rating scale (NRS) ranging from 0 (no pain) to 10 (worst imaginable pain) was used for pain assessments daily for 15 days and subsequently monthly until completing 3 months. Co-primary: Assessment of symptomatology related to phantom limb pain daily for 15 days POP and subsequently monthly until completing 3 months.

Bony landmarks and the space between the lower lumbar vertebrae are identified. Subsequently, infiltration of the skin and subcutaneous cellular tissue with local anesthetic (Lidocaine 2% without epinephrine) is performed at the site to be punctured. A 17G Tuohy needle is inserted 2-4 cm through the skin, then the mandrel is removed, the low-resistance syringe is connected, and the loss of resistance is checked using the air or liquid technique, depending on the preference of the anesthesiologist. . Appreciating the loss of resistance in the embolus, the mandrel is then withdrawn and the epidural catheter is advanced to leave it an additional 5 cm inside the epidural space.

The patient is placed in the prone or supine position with the limb to be blocked flexed at 90°. Using a high-frequency linear transducer and using sterile technique, the popliteal sciatic nerve is identified in an axial axis. A 17G Tuohy needle is inserted plane and medial. Saline solution (5 ml) is applied to open the perineural space. Adequate hydrodissection and donut sign in the nerve are observed..A perineural catheter is then advanced 5 cm beyond the tip of the needle. The catheter is fixed with stitches and a transparent sterile dressing is placed.

Pain score according to the daily NRS scale (Numeric Pain Rating Scale), Numeric Pain Rating Scale, for 15 days POP and subsequently monthly until completing 3 months. is scores from 0 to 10, 10 being the worst value.

For this qualitative dichotomous outcome, you will ask about symptomatology referring to phantom limb pain for 15 days POP and subsequently monthly until completing 3 months, It will be qualified as positive if it presents any neuropathic symptom.

Presence of phantom limb pain on a monthly basis until completing 12 month, The patient will be asked about the appearance of any painful sensation described as stabbing, shooting, electric shock, dull, tight pain and/or cramp in the anatomical site where the amputated limb would be, evaluating the presence or absence of the same (s). This will be questioned every day for 15 POPs days and monthly follow-up will continue via telephone until completing 3 months.

Incidence of nausea and vomiting POP in each group: the appearance of nausea or vomiting at 12, 24 and 36 h POP will be asked.

any appearance of hematoma, hypotension (defined as SBP less than 90 mmHg or a 30% decrease in baseline MAP) or bradycardia (HR less than 60 bpm) is defined.

Postoperative satisfaction measured with the EVAN LR scale (evaluation of local anesthetic satisfaction). It consists of a self-reported scale that measures satisfaction in the postoperative period of patients undergoing regional anesthesia in different surgical models (51), with an evaluation of 19 items structured in a global index and five unweighted dimensions, each of which covers some aspects such as Attention (4 items), Information (5 items), Discomfort (4 items), Waiting (2 items) and Pain (4 items). has a score for questions between 20 and 100 points, the lower the score, the lower satisfaction by dimension

Inclusion Criteria: Age over 18 years Being scheduled for above or below knee amputation or for bone remodeling of lower limb amputees Acceptance of continuous regional analgesic technique as part of their multimodal analgesia Exclusion Criteria: Traumatic cause of amputation Allergy to local anesthetics Contraindication for epidural technique or continuous blocks Stage 5 kidney disease Concomitant use of aspirin and clopidogrel Pregnancy status

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