Please select the eligibility criteria that correspond to the clinical trial below.
Title: A Randomized, Subject-Masked, Active-Controlled, Parallel-Arm Clinical Trial Comparing Erector Spinae and Paravertebral Nerve Blocks
Brief Summary: Following painful surgical procedures of the breast, postoperative analgesia is often provided with a paravertebral nerve block (PVB). For intense, but shorter-duration acute pain, a single-injection of local anesthetic is used with a duration of approximately 12 hours. The PVB has several limitations: it can decrease blood pressure, and very rare-but serious-complications have occurred, including neuraxial injection, neuraxial hematoma, and pleural puncture. An alternative block has been described: the erector spinae plane block. The theoretical benefits include ease of administration since it is a plane superficial to the PVB and therefore easier to identify and target with ultrasound (therefore increasing success rate); and an increased safety margin: there are few anatomic structures in the immediate area which could be injured with the needle; and, the target plane is much further from the intrathecal/epidural space relative to the PVB. Lastly, the plane may be easier to catheterize for continuous peripheral nerve blocks relative to the relatively-small volume PVB.

There are therefore multiple theoretical reasons to prefer the erector spinae plane block. Unfortunately, it remains unknown if the analgesia provided by this new technique is comparable to that provided with the PVB. The investigators therefore propose to compare these two techniques with a randomized, subject-masked, active-controlled, parallel-arm, human subjects clinical trial.


Options:
A: Inclusion Criteria:

* 25-70 years of agge
* ASA I-II
* Undergoing elective breast cancer surgery

Exclusion Criteria:

* obesity (body mass index \>35 kg/m2)
* infection of the skin at the site of needle puncture area
* patients with known allergies to any of the study drugs
* coagulopathy
* recent use of analgesic drugs
B: Inclusion Criteria:

* undergoing unilateral or bilateral breast surgery with at least moderate postoperative pain anticipated
* analgesic plan includes a single-injection peripheral nerve block(s)
* age 18 years or older.

Exclusion Criteria:

* morbid obesity as defined by a body mass index \> 40 (BMI=weight in kg / \[height in meters\]2)
* renal insufficiency (preoperative creatinine \> 1.5 mg/dL)
* chronic opioid use (daily use within the 2 weeks prior to surgery and duration of use \> 4 weeks)
* history of opioid abuse
* any comorbidity which results in moderate or severe functional limitation
* inability to communicate with the investigators or hospital staff
* pregnancy
* planned regional analgesic with perineural catheter placement
* incarceration
C: Inclusion Criteria:

* ASA I-II
* Age 18-65 years
* Undergoing elective lomber disc hernia

Exclusion Criteria:

* obesity
* ASA III - IV
* infection of the skin at the site of needle puncture area
* patients with known allergies to any of the study drugs
* coagulopathy
D: Inclusion Criteria:

* Age between 18 and 65 years
* American Society of Anesthesiologists physical status I-II-III
* Body mass index between 18-30 kg/m2
* Patients undergoing elective video assiste thoracoscopic surgery

Exclusion Criteria:

* Patient refusing the procedure
* History of chronic analgesic or opioid therapy
* History of local anesthetic allergy
* Infection in the intervention area
* Emergency surgery

Answer: B