Treatment of postmastectomy pain with ambulatory continuous paravertebral nerve blocks: a randomized, triple-masked, placebo-controlled study.
BACKGROUND
We aimed to determine with this randomized, triple-masked, placebo-controlled study if benefits are afforded by adding a multiple-day, ambulatory, continuous ropivacaine paravertebral nerve block to a single-injection ropivacaine paravertebral block after mastectomy.


METHODS
Preoperatively, 60 subjects undergoing unilateral (n = 24) or bilateral (n = 36) mastectomy received either unilateral or bilateral paravertebral perineural catheter(s), respectively, inserted between the third and fourth thoracic transverse process(es). All subjects received an initial bolus of ropivacaine 0.5% (15 mL) via the catheter(s). Subjects were randomized to receive either perineural ropivacaine 0.4% or normal saline using portable infusion pump(s) [5 mL/h basal; 300 mL reservoir(s)]. Subjects remained hospitalized for at least 1 night and were subsequently discharged home where the catheter(s) were removed on postoperative day (POD) 3. Subjects were contacted by telephone on PODs 1, 4, 8, and 28. The primary end point was average pain (scale, 0-10) queried on POD 1.


RESULTS
Average pain queried on POD 1 for subjects receiving perineural ropivacaine (n = 30) was a median (interquartile) of 2 (0-3), compared with 4 (1-5) for subjects receiving saline (n = 30; 95% confidence interval difference in medians, -4.0 to -0.3; P = 0.021]. During this same period, subjects receiving ropivacaine experienced a lower severity of breakthrough pain (5 [3-6] vs 7 [5-8]; P = 0.046) as well. As a result, subjects receiving perineural ropivacaine experienced less pain-induced physical and emotional dysfunction, as measured with the Brief Pain Inventory (lower score = less dysfunction): 14 (4-37) versus 57 (8-67) for subjects receiving perineural saline (P = 0.012). For the subscale that measures the degree of interference of pain on 7 domains, such as general activity and relationships, subjects receiving perineural saline reported a median score 10 times higher (more dysfunction) than those receiving ropivacaine (3 [0-24] vs 33 [0-44]; P = 0.035). In contrast, after infusion discontinuation, there were no statistically significant differences detected between treatment groups.


CONCLUSIONS
After mastectomy, adding a multiple-day, ambulatory, continuous ropivacaine infusion to a single-injection ropivacaine paravertebral nerve block results in improved analgesia and less functional deficit during the infusion. However, no benefits were identified after infusion discontinuation.
From the *Department of Anesthesiology, †Clinical Translational Research Institute, ‡Department of Ophthalmology, and §Department of Surgery, University of California San Diego, San Diego, CA.
Brian M
BM
Ilfeld
Sarah J
SJ
Madison
Preetham J
PJ
Suresh
Navparkash S
NS
Sandhu
Nicholas J
NJ
Kormylo
Nisha
N
Malhotra
Vanessa J
VJ
Loland
Mark S
MS
Wallace
James A
JA
Proudfoot
Anya C
AC
Morgan
Cindy H
CH
Wen
Anne M
AM
Wallace
D000328:Adult; D000553:Ambulatory Care / Q000379:methods*; D000577:Amides / Q000008:administration & dosage*; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D007260:Infusion Pumps; D007263:Infusions, Parenteral / Q000379:methods; D008408:Mastectomy / Q000009:adverse effects*; D008875:Middle Aged; D009407:Nerve Block / Q000379:methods*; D010149:Postoperative Pain / Q000175:diagnosis* / Q000188:drug therapy*; D000077212:Ropivacaine; D016896:Treatment Outcome
D000577:Amides; D000077212:Ropivacaine