Table 1. Characteristics of included studies evaluating the efficacy of TAP block after hysterectomy.

Study	Country	Type of surgery	Inclusion criteria	Exclusion criteria	Outcomes	Comparison group	Number TAP / Control Sequence generation and concealment	Blinding	Anesthetic drug dose (mg)	ASA	TAP block technique
Calle et al. (2014) 15	Colombia Prado Clinic and CES University, Medellin	Laparoscopic	Patients with ASA surgical risk classification types 1 and 2; had no contraindications for administration of local anesthetics, NSAIDs, or acetaminophen; had an adequate level of understanding, i.e., being able to communicate by telephone and understand a numerical scale.	Change in the standard anesthetic technique, hospitalization following hysterectomy, previous medical history of allergy to local anesthetics, and not being able to be reached by telephone	Pain scale scores (VAS) at 24, 48, and 72 hours after surgery, opioid requirement after surgery	Placebo	100 / 97 Sequence was generated using computer-generated randomization list in blocks, which were placed in sealed envelopes	Triple blind: Patient, surgeon, and data analyst	Bupivacaine 0.25% (96)	I, II	Laparoscopic-guided
De Oliveira et al. (2011) 13	United States of America Northwestern University, Chicago	Laparoscopic	Healthy women undergoing laparoscopic hysterectomy	Patients with previous history of allergy to local anesthetics, long-term use of opioid analgesics or corticosteroids, and pregnancy	Quality of Recovery (QoR-40) at 24h; pain numeric scale score at 30 minutes, 60 minutes, and 24 hours; time to opioid requirement and cumulative opioid consumption at 24 hours, and number of postoperative antiemetics	Placebo	22 / 23 Individuals were randomized into three groups using a computer-generated table of random numbers, and group assignments were sealed in sequentially numbered envelopes	Double blind: patients, anesthesia care providers	Ropivacaine 0.5% 100	I, II	Ultrasound
Ghisi et al. (2016) 16	Italy Instituti Ospitalieri Cremona	Laparoscopic	Patients between 18 and 70 years old, undergoing elective total laparoscopic hysterectomy	Chronic opioid therapy in the previous 3 months before surgery, conversion to open surgical technique, BMI > 30 kg/m 2 or < 18 kg/m 2 , postoperative recovery in intensive care unit, chronic therapy with antidepressants, known diagnosis of epilepsy or therapy with antiepileptic drugs, bilirubin level > 3.0 mg/dL, aspartate aminotransferase and/or alanine aminotransferase > 250 IU, creatinine level >1.4 mg/dL, pregnancy or lactation, known allergy to any drug used in the study, local infection at the block site, and drug or alcohol addiction.	Postoperative pain at rest and during movement using NRS of 0 to 10, at 2, 4, 6, and 24 hours. Morphine requirement 24 hours, incidence of postoperative nausea and vomiting (PONV) using the Apfel score	No block	22 / 22 Patients were randomized into two groups using computer-generated sequence of numbers placed in sealed envelopes	Single blind: observer (data collection)	Levobupivacaine 0.375% (75)	I - III	Ultrasound
Guardabassi et al. (2017) 18	Argentina Hospital Italiano de Buenos Aires	Laparoscopic	Patients between 18 and 70 years old; BMI < 35 kg/m 2 ; undergoing total laparoscopic hysterectomy	Previous medical history of allergy to local anesthetics; psychiatric disorders or dementia, abdominal wall infection; chronic use of analgesics, chronic pain syndrome; diagnosed peripheral neuropathy; known allergy to analgesics or corticoids.	Pain NRS: non-randomized study scores at 60 minutes, 2, 8, and 24 hours after surgery; opioid consumption during the first 24 postoperative hours; adverse effects on quality of sleep of the first night after surgery; episodes of nausea and vomit; Ramsay sedation scale	No block	20 / 20 Non-probability sampling of consecutive case series. Random assignment using sealed envelopes	Single-blind: Data analysts	Ropivacaíne 0.5% (75)	I, II	Ultrasound
Bava et al. (2016) 17	China Department of Anesthesiology and Operation, Hospital of People's Liberation Army. Xi'an	Laparoscopic and LAVH	Women scheduled for elective laparoscopic hysterectomy with benign lesions	Patients with preoperative use of analgesics were excluded due to potential impact on postoperative analgesia requirement; BMI > 30 kg/m 2 ; coagulopathy; contraindication for peripheral nerve block; any drug allergy	Pain, with NRS: 30 and 60 minutes, 4, 8, 12, and 24 hours PONV, Ramsay sedation scale Satisfaction scores	No block	35 / 36 Computer-generated randomization list in blocks, placed in sealed envelopes	Double-blind: blinded to patients and data analysts, but not to members of the surgical and anesthesia care teams	Ropivacaine 0.375% (112.5)	—	Ultrasound
Kane et al. (2012) 14	United States of America Metrohealth Medical Center, Case Western Reserve University, Cleveland	Laparoscopic and single-port	All women undergoing laparoscopic hysterectomy by a single surgeon between April and September 2011 were approached to participate in this study.	Patients on chronic pain narcotic medications, or if they had allergy to local anesthetic.	Numeric visual analog scales for pain and opioid requirement at 2 and 24 hours after surgery; quality of recovery (QoR-40 survey) at postoperative day 1	No block	28 / 29 Computer-based block randomization	Single-blind: blinded to data analysts	Ropivacaine 0.5% with epinephrine (100)	—	Ultrasound

Abbreviations: ASA, American Society of Anesthesiology; BMI, body mass index; NRS, non-randomized study; NSAIDS, nonsteroidal anti-inflammatory drugs; PONV, Postoperative nausea and vomiting.