Nerve Block for Pain Control After Fracture Surgery

Background:

Open reduction and internal fixation (ORIF) surgery for a fracture of the ankle or distal radius is a commonly performed outpatient orthopedic procedure. Surgery is routinely performed under a preoperative peripheral nerve block (PNB) with sedation, or under general anesthesia (GA) with supplemental postoperative PNB for analgesic purposes. The method chosen is often influenced by the opinion and experience of the anesthetic team. There is no consensus as to whether PNB should be utilized preoperatively, or reserved for 'as needed' cases postoperatively.

The use of PNB in fracture surgery has been recommended in order to reduce perioperative opioid analgesic requirements and improve postoperative pain, particularly in the context of the ongoing opioid epidemic. For patients undergoing ORIF for ankle or distal radius fractures, successfully administered PNB can provide excellent pain relief in the first 8 to 12 hours post-surgery. However, a concern with PNB is rebound pain, the presence of delayed acute postoperative pain at 12 to 24 hours, affecting up to 50% of patients.

With a majority of extremity fracture surgeries performed on an outpatient basis, patients who experience rebound pain will do so after leaving hospital. PNB might therefore not provide satisfactory analgesia when patients are in most need of it. Instead, GA might offer a more desirable postoperative pain profile with patients experiencing peak pain intensity shortly after surgery, followed by steady improvement prior to discharge. In the context of rationalizing the potency of discharge prescription opioids, having less pain post-discharge is preferable.

Rather than universally adopting preoperative PNB for those undergoing ankle or distal radius ORIF, a more targeted approach might improve patients' postoperative pain experience. Performing surgery under GA, and offering postoperative PNB 'as needed' to those whose pain is poorly controlled, has the advantage of avoiding the risks of PNB administration (and potential post-discharge rebound pain) in patients whose pain is manageable after GA. Furthermore, while preoperative PNB is associated with decreased intraoperative opioid requirement, there is no consensus that offering PNB postoperatively is clinically inferior in terms of the analgesia provided, or the subsequent risk of rebound pain.

Primary Aim:

The primary aim of the trial is to determine if any difference exists between (1) preoperative PNB and (2) GA with 'as needed' postoperative PNB with respect to the primary outcome measure, reported pain intensity (0-10, visual analogue scale), at 24 hours post-surgery for adult patients undergoing ORIF for a fracture of the ankle or distal radius.

Secondary Aims:

The secondary aims include determining if a difference exists between groups with regards to pain at discharge, pain 12 hours post-surgery, pain at 48 hours, pain at 72 hours. In addition, the functional activity scale and analgesic consumption (opioid plus nonopioid) will be compared at these time points.

Methodology:

Single-center, prospective, randomized, open label, superiority trial including adult patients receiving surgery for an acute, isolated, fracture of either the ankle or distal radius.

The minimum clinically important difference for pain, as reported in the pain literature, is 1.5 to 2 points on an eleven-point (0 to 10) visual analogue scale. An a priori power analysis determined that 68 participants would provide sufficient power to detect a difference in mean pain scores of 1.5 or more between trial groups, assuming a standard deviation of 2.2 points (alpha 0.05, 80% power).

Suitable patients will be recruited from the outpatient orthopedic clinic. Participants will be randomized to one of two groups for each fracture type (ankle and wrist) using 3 blocks of sealed study envelopes: "PNB" or "GA+/-PNB". They will then be scheduled on the next available OR list as either the first or second case to allow time for postoperative data capture. Routine postoperative prescriptions will be sent electronically to the pharmacy and participants will be given written trial material to take home and review.

Willingness to participate in the trial will be confirmed on the day of surgery, and the method of anesthesia confirmed with the anesthesiologist and nurse anesthetist. Following surgery, PNB patients will return to the Day Surgery Unit (DSU) and GA patients will be taken to the Post Anesthesia Care Unit (PACU). Standard analgesia will be administered to both groups as part of routine care.

GA patients whose pain is poorly controlled despite multiple doses of short-acting opioid will be offered PNB postoperatively. This postoperative PNB will be administered at the discretion of the PACU team and anesthesiologist.

Pain scores and analgesic consumption will be recorded for each trial participant prior to discharge from hospital. A contact telephone number will be confirmed.

The participant will be contacted by telephone to obtain outcome data at 12 hours (evening of surgery), 24 hours (following morning), at 48 hours and at 72 hours. During each call, patients will be routinely counseled about postoperative pain management. All other office follow-up visits will be competed as part of routine.