Postoperative Pain clinical trials at University of California Health

Patients undergoing ACL repair with hamstring autograft frequently develop significant post operative pain at the hamstring grafting site. This pain is within the distribution of a commonly used regional nerve block, the Interspace between the popliteal artery and capsule of the knee (iPACK). The investigators plan to randomize consenting patients to either receiving a SHAM injection of normal saline or to an interventional group of long acting local anesthetic (Ropivacaine) injected in the popliteal fossa between the popliteal artery and capsule of the knee (iPACK). Both groups of patients will receive standard of care with respect to perioperative pain management, which includes a preoperative adductor canal nerve block and preoperative acetaminophen administration. Dual primary endpoints of postoperative pain scores and mean postoperative opioid use will be retrieved and compared between groups. Additional secondary endpoints will be PACU length of stay, PACU opioid use, POD1 opioids use, and POD1 pain scores (best, worst, average).

This will be a randomized comparison of continuous local anesthetic infusion with patient controlled boluses (PCA) to patient-titratable automated boluses with patient controlled boluses (PCA) for both infraclavicular and popliteal-sciatic perineural catheters. The overall goal is to determine the relationship between method of local anesthetic administration (continuous with PCA vs. titratable intermittent dosing with PCA) for these two perineural catheter locations and the resulting pain control. The investigators hypothesize that, compared with a traditional fixed, continuous basal infusion initiated prior to discharge, perineural local anesthetic administered with titratable automated boluses at a lower dose and a 5-hour delay following discharge will (1) provide at least noninferior analgesia during the period that both techniques are functioning; and, (2) will result in a longer overall duration of administration [dual primary end points].

The moderate-to-severe pain many patients experience following surgery is often treated with opioids, which are associated with side effects such as nausea/vomiting, sedation, and respiratory depression (and a risk of abuse, dependence, and diversion). Potent site-specific analgesia with fewer side effects may be provided with peripheral nerve blocks. However, these too have limitations such as a duration of action measured in hours, while the pain from surgery is usually measured in days or weeks. Peripheral nerve stimulation or "neuromodulation" is an alternative method of pain control involving the introduction of electrical current to stimulate various nerves that do not carry pain sensations, but which then decreases communication between pain fibers and the spinal cord and/or brain. Placing small electrodes specifically in the area of the ear is called "auricular neuromodulation" and is theorized to function by stimulating various cranial and peripheral nerves that influence a part of the brain called the "limbic system" which is involved with many aspects of behavior including responses to stress. A device that delivers auricular neuromodulation, the "Bridge" system, is approved by the United States Food and Drug Administration for use to reduce symptoms associated with opioid withdrawal for up to 5 days. However, one prospective and two published retrospective studies suggest that it may provide postoperative analgesia as well. The device itself is relatively simple to apply; has few contraindications, side effects, or adverse events; and has no potential for dependence, abuse, or diversion. Therefore, it has the potential to concurrently improve analgesia and decrease or even negate opioid requirements following surgery, only without the limitations of opioids and peripheral nerve blocks. The purpose of this pilot study is to explore the possibility of treating postoperative pain with percutaneous auricular neuromodulation, optimize the study protocol, and estimate the treatment effect in preparation for developing a subsequent definitive clinical trial.

Pulsed electromagnetic field therapy is a possible method of pain control involving the application of electromagnetic energy (also termed nonthermal, pulsed, shortwave radiofrequency therapy). Food and Drug Administration-cleared devices have been in clinical use for over 70 years. For decades, available devices consisted of a large signal generator and bulky coil applicator that were not portable and produced significant electromagnetic interference, making them impractical for common use. However, small, lightweight, relatively inexpensive, noninvasive, Food and Drug Administration-cleared devices that function for 30 days are now available to treat acute and chronic pain, decrease inflammation and edema, and hasten wound healing and bone regeneration. Therefore, it has the potential to concurrently improve analgesia and decrease or even negate opioid requirements, only without the limitations of opioids and peripheral nerve blocks. The purpose of this pilot study is to explore the possibility of treating acute postoperative pain with nonthermal, pulsed shortwave (radiofrequency) therapy, optimize the study protocol, and estimate the treatment effect in preparation for developing subsequent definitive clinical trials.

Pulsed shortwave (radiofrequency) therapy is a possible method of pain control involving the application of electromagnetic energy (also termed pulsed electromagnetic fields). Food and Drug Administration-cleared devices have been in clinical use for over 70 years. For decades, available devices consisted of a large signal generator and bulky coil applicator that were not portable and produced significant electromagnetic interference, making them impractical for common use. However, small, lightweight, relatively inexpensive, noninvasive, Food and Drug Administration-cleared devices that function for 8 days are now available to treat acute and chronic pain, decrease inflammation and edema, and hasten wound healing and bone regeneration. Therefore, it has the potential to concurrently improve analgesia and decrease or even negate opioid requirements, only without the limitations of opioids and peripheral nerve blocks. The purpose of this study is to explore the possibility of treating acute postoperative pain with nonthermal, pulsed shortwave (radiofrequency) therapy, optimize the study protocol, and estimate the treatment effect.

Breast cancer is the most common type of cancer in women. Removal of the breast, called "mastectomy", is performed either when there is cancer-or an increased risk of cancer-in the breast. This can result in a lot of pain during the months after surgery. Opioids-"narcotics"-are the most common pain control method provided to patients; but they frequently do not relieve enough pain, have undesirable side effects like vomiting and constipation, and are sometimes misused which can lead to addiction. Mastectomy also frequently results in long-term pain which can interfere with physical and emotional functioning; and the more pain patients have immediately after surgery, the greater the risk of developing long-term pain. Numbing the nerves with local anesthetic can decrease the amount of short- and long-term pain experienced by patients, but even the longest types of these nerve blocks last for hours or days, and not the 1-2 months of pain typically following mastectomy. So, there is reason to believe that if the nerve blocks could be extended so that they last longer than the pain from surgery, short- and long-term pain might be avoided completely without the need for opioids. A prolonged nerve block may be provided by freezing the nerve using a technique called "cryoneurolysis". With cryoneurolysis and ultrasound machines, a small needle-like "probe" may be placed through anesthetized skin and guided to the target nerve to allow freezing. The procedure takes about 5 minutes for each nerve, involves little discomfort, has no side effects, and cannot be misused or become addictive. After 2-3 months, the nerve returns to normal functioning. The investigators have completed a small study suggesting that a single cryoneurolysis treatment may provide potent pain relief after mastectomy. The ultimate objectives of the proposed research study are to determine if temporarily freezing the nerves that go to the breast will decrease short-term pain, opioid use, physical and emotional dysfunction, and long-term pain following mastectomy when added to current and customary postoperative analgesics. The current project is a pragmatic, multicenter, randomized, triple-masked (investigators, participants, statisticians), sham/placebo-controlled, parallel-arm, human-subjects, post-market clinical trial to determine if cryoneurolysis is an effective non-opioid treatment for pain following mastectomy.

Postoperative pain is usually treated with opioids that have undesirable and sometimes dangerous side effects (e.g., vomiting and respiratory depression)-and yet over 80% of patients still experience inadequate pain relief. A novel, non-pharmacologic analgesic technique-percutaneous peripheral nerve stimulation (PNS)- holds extraordinary potential to greatly reduce or obviate opioid requirements and concurrently improve analgesia following painful surgery. This technique involves inserting an insulated electric lead adjacent to a target nerve through a needle prior to surgery using ultrasound guidance. Following surgery, a tiny electric current is delivered to the nerve resulting in potent pain control without any cognitive or adverse systemic side effects whatsoever. The electrical pulse generator (stimulator) is so small it is simply affixed to the patient's skin. The leads are already cleared by the US Food and Drug Administration to treat acute (postoperative) pain for up to 60 days; and, since percutaneous PNS may be provided on an outpatient basis, the technique holds the promise of providing potent analgesia outlasting the pain of surgery-in other words, the possibility of a painless, opioid-free recovery following surgery. The current project is a multicenter, randomized, quadruple-masked, placebo/sham-controlled, parallel-arm pragmatic clinical trial to determine the effects of percutaneous PNS on postoperative analgesia and opioid requirements, as well as physical and emotional functioning, the development of chronic pain, and ongoing quality of life.