RA for breast surgery


breastsq

  

Dr Alexander Schnabel

 

Breast cancer remains the most common cancer in women. 1, 2 Fortunately, due to improvements in early diagnosis and treatment (including breast conserving surgery), breast cancer survival continues to improve. However, several prospective trials have demonstrated that chronic postsurgical pain occurs in up to 40% of women undergoing this surgery. 3, 4 A recently published Cochrane meta-analysis confirmed the effectiveness of regional anaesthesia techniques for the prevention of chronic postsurgical pain for a variety of surgical procedures. This association has been hypothesised as being due to improved acute pain management and/or reduced central sensitization and opioid induced hyperalgesia. 5 Becuse LA placed within the paravertebral space can provide the dermatomal blockade appropriate for breast surgery, paravertebral nerve block is well suited to this surgery for reducing both acute and chronic postsurgical pain.


Efficacy of paravertebral block for breast surgery

For the traditional landmark based technique, block success rates for both lumbar and thoracic blocks have been reported to be over 90%. Two published meta-analyses have focussed on paravertebral blocks in the setting of breast surgery, and reported significantly lower postoperative pain scores for paravertebral block alone compared to general anaesthesia (GA) alone: < 2 h postop: -2.5 U (NRS, 0-10); 6, 7 < 24 h: -1.7 U; 6, 7 < 48 h: -1.8 U 6). Results were similar for paravertebral block combined with GA vs. GA alone. 6 Additionally, paravertebral block for breast surgery (as the sole anaesthetic technique or in combination with GA) reduces opioid requirements, and consequently lowers the postoperative nausea and vomiting risk. 6, 7 A recently published large retrospective analysis demonstrated that the addition of paravertebral block to GA for reconstructive mastectomy reduced length of hospital stay. 8 A recent randomised trial has also demonstrated that paravertebral block improves analgesia following simple breast augmentation. 18 In that study, the authors randomized 40 women undergoing bilateral breast augmentation to intraoperative wound site local infiltration, or preoperative bilateral paravertebral block. Surgery was conducted under propofol sedation without airway instrumentation. Paravertebral block was by a single T4 level injection of 20 mL ropivacaine 0.75%. The infiltration group received the same volume (20 mL x 2) of ropivacaine (presumably 0.75%). For the paravertebral group, propofol requirement was lower, intraoperative cooperation was better, PACU opioid use was lower, and average pain was reduced for the first 3 postoperative days.


Paravertebral block safety in breast surgery

The most commonly reported paravertebral block adverse events are vascular puncture (6.8%), hypotension (4%), epidural or intrathecal spread (1%), pleural puncture (0.8%) and pneumothorax (0.5%). 9 However, in the setting of breast surgery where patients are typically younger with better surface anatomy, the frequency of these adverse events is reported to be lower: temporary HornerĀ“s syndrome occurs relatively commonly but one meta analysis revealed only one case of pneumothorax and one vascular puncture. 6 Another systemic review reported the most common adverse event as hypotension/bradycardia (n=11), presumably related to epidural LA spread. 7 These low complication rates confirm the safety of the technique for breast surgery; the ultrasound-guided technique could be expected to afford even greater safety. 10


Unresolved controversies

Despite a growing body of evidence for paravertebral block, the optimal local anaesthetic dose (with or without LA additive) for breast surgery remains unknown. Most published reports have used 3-4 ml of ropivacaine or bupivacaine 0.375-0.5% per thoracic segment blocked. Furthermore, whether the optimal technique involves a single injection block, a multi injection (multi-level) block or a continuous technique also remains unknown. Subgroup analysis of one published meta-analysis demonstrated that multiple injections are more efficient than a single injection, but acknowledged that the multi injection technique might be associated with an increased risk of needle puncture related complications. 6

As mentioned above, paravertebral blocks provide effective pain control following breast surgery and three randomised trials have confirmed the assumption that this translates into a reduced risk of chronic postsurgical pain. 11-13 However, more trials focusing on this issue are needed.

Another emerging issue is the suggestion that paravertebral block reduces breast cancer recurrence risk. Exadaktylos and colleagues demonstrated in a retrospective analysis of 129 patients undergoing mastectomy and axillary clearance under either paravertebral block with GA or GA only, that paravertebral block was associated with a reduced rate of tumour recurrence and more frequent metastasis-free survival. 14 This might be explained by paravertebral block reducing cytokine alteration, which might be necessary in providing perioperative cancer immunity. 15 Additionally, the same authors showed that paravertebral block with propofol sedation inhibited the proliferation of oestrogen receptor-negative breast cancer cells to a greater extent than GA alone. 16 Currently, at least one large multicenter randomised controlled trial is investigating the risk of breast cancer recurrence following paravertebral block (and sedation) compared to GA alone, 17 and will go a long way in clarifying this important issue.

 

Thoracic wall blocks ("PECS" block)

Because of the previously described complications, many practitioners are not comfortable performing paravertebral block.  In addition, paravertebral block will not provide complete sensory block to the anterior chest wall, as the chest is supplied not only from the thoracic spinal nerves, but also the brachial plexus via the medial and lateral pectoral nerves. Thoracic wall blocks ("PECS" block) have been recently described as an alternative peripheral nerve block to paravertebral block for providing both surgical anesthesia and postoperative analgesia for breast surgery. All rely on LA placement between the thoracic wall muscles. Thoracic wall blocks are to the chest what the TAP (transversus abdominis plane) block is to the abdomen. Like the TAP block, their introduction has been facilitated by the widespread availability of portable ultrasound. However, despite theoretical and anatomical arguments supporting their use for this surgery, at present, supportive clinical data is lacking.

 

References


1. American Cancer Society. Overview: Breast cancer. 2009;.

2. Tyczynski JE, Bray F, Parkin DM. ENCR cancer fact sheets: Breast cancer in europe. 2002;(02.06/2010): 4.

3. Gartner R, Jensen MB, Nielsen J, Ewertz M, Kroman N, Kehlet H. Prevalence of and factors associated with persistent pain following breast cancer surgery. JAMA 2009;302(18): 1985-1992.

4. Tasmuth T, von Smitten K, Hietanen P, Kataja M, Kalso E. Pain and other symptoms after different treatment modalities of breast cancer. Ann Oncol 1995;6(5): 453-459.

5. Andreae MH, Andreae DA. Local anaesthetics and regional anaesthesia for preventing chronic pain after surgery. Cochrane Database Syst Rev 2012;10: CD007105.

6. Schnabel A, Reichl SU, Kranke P, Pogatzki-Zahn EM, Zahn PK. Efficacy and safety of paravertebral blocks in breast surgery: A meta-analysis of randomized controlled trials. Br J Anaesth 2010;105(6): 842-852.

7. Tahiri Y, Tran de QH, Bouteaud J, Xu L, Lalonde D, Luc M, Nikolis A. General anaesthesia versus thoracic paravertebral block for breast surgery: A meta-analysis. J Plast Reconstr Aesthet Surg 2011;64(10): 1261-1269.

8. Coopey SB, Specht MC, Warren L, Smith BL, Winograd JM, Fleischmann K. Use of preoperative paravertebral block decreases length of stay in patients undergoing mastectomy plus immediate reconstruction. Ann Surg Oncol 2013;20(4): 1282-1286.

9. Richardson J, Lonnqvist PA. Thoracic paravertebral block. Br J Anaesth 1998;81(2): 230-238.

10. Riain SC, Donnell BO, Cuffe T, Harmon DC, Fraher JP, Shorten G. Thoracic paravertebral block using real-time ultrasound guidance. Anesth Analg 2010;110(1): 248-251.

11. Kairaluoma PM, Bachmann MS, Rosenberg PH, Pere PJ. Preincisional paravertebral block reduces the prevalence of chronic pain after breast surgery. Anesth Analg 2006;103(3): 703-708.

12. ohom G, Abdalla H, O'Brien J, Szarvas S, Larney V, Buckley E, Butler M, Shorten GD. The associations between severity of early postoperative pain, chronic postsurgical pain and plasma concentration of stable nitric oxide products after breast surgery. Anesth Analg 2006;103(4): 995-1000.

13. Ibarra MM, S-Carralero GC, Vicente GU, Cuartero del Pozo A, Lopez Rincon R, Fajardo del Castillo MJ. Chronic postoperative pain after general anesthesia with or without a single-dose preincisional paravertebral nerve block in radical breast cancer surgery. Rev Esp Anestesiol Reanim 2011;58(5): 290-294.

14. Exadaktylos AK, Buggy DJ, Moriarty DC, Mascha E, Sessler DI. Can anesthetic technique for primary breast cancer surgery affect recurrence or metastasis? Anesthesiology 2006;105(4): 660-664.

15. Deegan CA, Murray D, Doran P, Moriarty DC, Sessler DI, Mascha E, Kavanagh BP, Buggy DJ. Anesthetic technique and the cytokine and matrix metalloproteinase response to primary breast cancer surgery. Reg Anesth Pain Med 2010;35(6): 490-495.

16. Deegan CA, Murray D, Doran P, Ecimovic P, Moriarty DC, Buggy DJ. Effect of anaesthetic technique on oestrogen receptor-negative breast cancer cell function in vitro. Br J Anaesth 2009;103(5): 685-690.

17. Sessler DI, Ben-Eliyahu S, Mascha EJ, Parat MO, Buggy DJ. Can regional analgesia reduce the risk of recurrence after breast cancer? methodology of a multicenter randomized trial. Contemporary Clinical Trials 2008;29(4): 517-526.

18. Gardiner S, Rudkin G, Cooter R, Field J, Bond M. Paravertebral blockade for day-case breast augmentation: a randomized clinical trial. Anesth Analg. 2012 Nov;115(5):1053-9.