Could freezing chest nerves replace opioids after mastectomy?

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: 1. Adult patients of at least 18 years of age 2. Undergoing unilateral or bilateral total or modified radical mastectomy Exclusion Criteria: 1. Anticoagulation or bleeding disorder: introduction of the percutaneous cryoneurolysis probe has a risk of hemorrhage similar to the percutaneous insertion of a similar gauge needle; but an anticoagulated state will increase the risk of hemorrhage (aspirin in doses for cardiothoracic/stroke prophylaxis \[≤ 325 mg\] are acceptable). 2. Infection at the site of probe introduction: percutaneous insertion of the probe through a cutaneous infection would bring an unacceptable risk of introducing the infection to deeper tissues. 3. Pulmonary disease requiring supplemental oxygen: one theoretical risk of cryoneurolysis is a unilateral pneumothorax (not reported) which could result in a compromised pulmonary state for patients who require supplemental oxygen at baseline. 4. Possessing any contraindication to decreased temperature such as cryoglobulinemia, cryofibrinogenemia, cold urticaria, paroxysmal cold hemoglobinuria, or Raynaud's disease: the decreased temperature accompanying cryoneurolysis could result in local tissue/vascular compromise for patients with any of these cold-triggered syndromes/diseases. 5. Neurologic deficit of the 2nd-6th ipsilateral intercostal nerves: cryoneurolysis is theoretically a potent analgesic, but it does not "heal" injured nerves. Therefore, pre-existing nerve deficits will confound the analgesia-related results. 6. Chronic opioid use (daily use within the 2 weeks prior to surgery and duration of use \> 4 weeks, either by self-report or recorded previously in the medical record): individuals using opioids on a chronic basis will continue their baseline opioid requirements postoperatively. This will confound the analgesic results of the study. 7. Insulin-dependent diabetes: laboratory studies have demonstrated impaired nerve regeneration in diabetic animals, and diabetes in patients can lead to impaired regeneration of axons and recovery following investigational nerve injury65 as well as focal neuropathies such as ulnar neuropathy and carpal tunnel syndrome. Whether these findings are applicable to cryoneurolysis in patients with diabetes remains unknown, but we prefer to err on the side of caution for study participants. 8. Contralateral breast surgical procedure that does not include mastectomy. 9. Inability to remain in contact with the investigators during the study period (e.g., lack of telephone access).