The objective of this study is to evaluate the safety and clinical utility of the active, SSEC fentanyl 40 micrograms (mcg) for the management of acute, postoperative pain in pediatric participants.

An open label evaluation of the safety and clinical utility of the active, SSEC fentanyl 40 mcg for the management of acute postoperative pain in pediatric participants 12 to less than 18 years of age.

Inclusion Criteria:

• Participants whose parent(s) or guardian(s) have/has signed and dated an informed consent form for the participant to participate in the study, or participants who have provided written assent to participate in the study
• Male or female inpatients, age 12 to <18 years of age inclusive on the day of surgery
• Participants capable of understanding and cooperating with the requirements of the study, including being able to report their pain intensity using the 11-point Numeric Rating Scale and operate the SSEC
• American Society of Anesthesiologists physical status I, II or III
• Body weight of at least 40.0 kilogram (kg)
• Postoperative participants who have undergone general or regional anesthesia for abdominal, pelvic/genitourinary, orthopedic, or thoracic surgery
• Postoperative participants who have been observed during recovery and are expected to remain hospitalized and have pain requiring parenteral opioids (that is, intravenous [IV] patient-controlled anesthesia) for the next 24 hours or longer
• Participants who are awake and breathing spontaneously with a respiratory rate of 14 to 18 breaths per minute, peripheral capillary oxygen saturation ≥93% (with or without supplemental oxygen), and able to answer questions and follow commands
• Participants who have been observed during recovery, who are awake, able to answer questions and follow commands, and who have been comfortable for at least 30 minutes, with a pain intensity score ≤4 (numeric rating scale 0-10), with or without titration to comfort with IV opioids

Exclusion Criteria:

• Participants who have undergone any surgery on the airway, head, or neck
• Participants who received an extended-release opioid within 48 hours prior to Hour 0 or who are expected to have postoperative analgesia supplied by a continuous regional technique or participant-controlled epidural analgesia
• Participants with a history of allergy or hypersensitivity to fentanyl, skin adhesives, and/or cetylpyridinium chloride
• Participants who are expected to require intensive care or will likely require additional surgical procedures within 36 hours
• Participants who received intra-operative and/or postoperative administration of opioids other than morphine, hydromorphone, fentanyl, sufentanil, or alfentanil. Exception: If there are no medical contraindications, meperidine (pethidine) up to 0.5 milligram/kg IV is permitted during recovery for shivering
• Participants who require airway support (nasal or oropharyngeal airway intubation, or laryngeal mask airway at the time of final baseline assessments (that is, at the time of IONSYS application [Hour 0])
• Participants who are known or suspected to be opioid tolerant, have a history of opioid dependence within 3 months before the start of the study, or who are known to have used illicit drugs or alcohol within 14 days of the start of the study
• Participants with active generalized skin disorders or active local skin disease that precludes SSEC application to the chest or upper arm
• Participants with any coexisting major medical conditions that are likely to interfere with study procedures including, but not limited to, psychiatric conditions, chronic depression, suicidal ideation, autism
• Positive pregnancy test for any female