Sunday, October 10, 2004

Botulinum Toxin (BT) Infiltration for Pain Control after Mastectomy and Subpectoral Tissue Expansion

Julio Hochberg, MD, Rakshanda Layeeque, MD, Rhonda Tillman, MD, Kent Westbrook, MD, James C. Yuen, MD, Kelly M. Kunkel, RN, and Suzanne V. Klimberg, MD.

Objective: To investigate if the intramuscular infiltration of the chest wall musculature with BT after mastectomy with tissue expander placement (M/TE) would inhibit postoperative spasm and pain during expansion.

Methods: A prospective non-randomized study was conducted between July 2001 and February 2004. All patients underwent M/TE with (cases) or without (controls) infiltration of 100 units of BT diluted in 40 - 60 cc of normal saline into Pectoralis Major, Serratus Anterior and insertion of Rectus Abdominis. Comparisons were made of procedure indications, demographics and pain, postoperatively and during expansion. Pain was scored using a visual analogue scale of 0-10 (0 = no pain, 10 = worst pain). Wilcoxon rank sum test and the chi-square test were used to test for significance.

Results: Fifty-six patients underwent M/TE followed by implant placement; 30(53.5%) with and 26 (46.4%) without BT. The two groups were comparable in terms of age (53+7 yrs vs. 50+3 yrs; p=0.48), bilaterality of procedure (60% vs. 62%; p=0.90), tumor size (1.1+0.2 cm vs. 1.0+0.5 cm; p=0.4), expander size (550+100 cc vs. 450+100 cc; p= 0.23), expansion volume (445+95 cc vs.; 450+70 cc p=0.67) and percentage expansion achieved (78+12% vs. 90+17%; p= 0.18). The BT group did significantly better in terms of postoperative pain (score of 3+1 vs. 6+1; p<0.0001), morphine used during 24 hours postoperatively (2+1 mg vs. 19+9 mg; p=0.0003), pain during initial expansion (score of 2+1 vs. 6+2; p< 0.0001), pain during final expansion (0+1 vs. 3+2; p=0.003) and number of sessions required to achieve target expansion (4+1 vs. 7+3; p=0.025). One patient required a repeat BT infiltration under ultrasound guidance. There was significant difference in length of hospital stay between BT group and controls (23+7 vs. 37+12 hours; p=0.01); however time to permanent implant placement was not significantly different (6+3 vs. 7+4 months; p= 0.44). One expander (due to pain) in the BT group and 5 (2 due to infection and 3 due to pain) in the control group were removed before plan (p=0.13). No complications related to BT injections were reported.

Conclusion: Muscular infiltration of BT for M/TE significantly reduced postoperative pain and discomfort due to tissue expansion without complications.