Retraction Notice Pectoral Nerves Block Is Effective for Motor Function Recovery in the Early Postoperative Period after Breast Cancer Surgery

Background: Pectoral nerves (PECS) block has been reported to be effective for a perioperative analgesia for breast cancer surgery. In addition, we may consider that the PECS block is also effective for motor function in postoperative period. Therefore, we investigated the effect of PECS block for motor function in postoperative period. Methods: This study selected the patients performed the breast cancer surgery between April and September, 2015. The study surveyed the difficulty of movement of the upper limbs at postoperative day 5 (D5) and postoperative month 6 (M6) by performing telephone survey. We counted the number of patients who complained of the difficulty of movement of the upper limbs. All results were compared using the chi-squared test. P < 0.05 was considered statistically significant. Results: 93 patients received only general anesthesia (G group). 85 patients received PECS block with general anesthesia (P group). The number of the P group at D5 was 2 patients. On the other hand, the number of the G group was 15 patients (P = 0.042). In the same way, the number of the P group M6 was no patient. On the other hand, the number of the G group was 10 patients (P = 0.043). Conclusion: A PECS block is effective for motor function recovery in the early postoperative period after breast cancer surgery.


Introduction
Pectoral nerves (PECS) block is a block that can be used for multiple lateral cu-How to cite this paper: Hara, E., Ueshima taneous anterior branches of intercostal nerves (Th2-6) present in the internal mammary region, and is reported to be effective for acute postoperative analgesia after breast cancer surgery [1] [2] [3]. In addition, a local anesthetic for primary cancer surgery must have some advantages, such as reduced incidence of recurrence and metastasis [4].
A PECS block is generally performed by administrating the first injection between the pectoralis major and pectoralis minor at the third rib and second injection between the pectoralis minor and serratus muscles at the fourth rib [5] [6]. However, the first injection normally does not provide analgesic efficacy because the nerve that is blocked by the first injection is a motor nerve, such as the lateral pectoralis muscle nerve and internal pectoralis muscle nerve. However, as reported, motor nerve block can prevent muscle contraction, while the PECS block may be effective for motor recovery of the upper limb after breast cancer surgery [7] [8]. In this study, we retrospectively investigated the effect of the PECS block on motor function during the postoperative period.

Patients and Design
This retrospective study was approved by the Showa University Hospital Institutional Review Board (approval number 1952). In addition, the study was regis-

Ultrasound-Guided PECS block
We used a 12 L-RS linear probe of the LOGIQ e Premium system (GE Healthcare Japan, Tokyo, Japan) for an ultrasound-guided PECS block. Before the block, the precordium was firmly cleaned with chlorhexidine. The blocks were then performed using a 20-gauge Tuohy needle. A PECS block was administered by injecting 10 mL of 0.15% levobupivacaine between the pectoralis major and pectoralis minor at the third rib (first injection) and 25 mL of 0.15% levobupivacaine above the serratus anterior muscle (second injection).

Statistical Analysis
The age of the patients, body mass index (BMI), operation time, anesthesia time,

Results
213 patients were included during the study period. Of these patients, 93 patients received only general anesthesia (G group). The other 85 patients received PECS block with general anesthesia (P group). 35 patients (G group: 30 patients, P group: 5 patients) were excluded from the study because of not connecting phone ( Figure 1).
Patient demographics are presented in Table 1. The amount of fentanyl administered to the P group during the surgery was lower than that administered to the G group (P = 0.0011). The number of difficulties related to motor functioning of the upper limbs in the P group (2) was lower than that in the G group (15) at D5 (P = 0.042). The number of difficulties related to motor function of the upper limb in the P group (0) was lower than that in the G group (10) at M6 (P = 0.043; Table 2). The upper limb motor functions that were affected in the G group were mainly flexion and internal rotation (Table 3).

Discussion
The results of this study revealed that administration of a PECS block aided in the early recovery of motor function of the upper limbs during the postoperative stage of breast cancer. A PECS block can provide not only relief from acute pain during the perioperative period but also aids in the early recovery of motor function of the upper limbs. In addition, since the upper limb motor functions that were affected were mainly flexion and internal rotation in the G group, which involved the pectoralis major muscle, we speculate that the first injection, which can block the pectoral nerve-dominated pectoralis major muscle, was ef-    fective for the recovery of upper limb motor functions [9]. In other words, the muscle contraction prevention by first injection may promote the recovery of upper limb motor functions.
There were some limitations to this study. Firstly, this study was a retrospective study. Therefore, we performed the telephone survey. He should need not only the telephone survey but a medical examination. Also, the nerves that dominate the pectoralis major muscle involve not only the pectoral nerves but also the anterior branches of the spinal nerves. We need to investigate which anterior branches affect the pectoralis major muscle.
In the future, we need to conduct a prospective study with a longer study duration than a postoperative month 6.

Conclusion
The results of this study indicate that the PECS block (especially, first injection)

R E T R A C T E D Open Journal of Anesthesiology
can prevent contraction of the pectoralis major and pectoralis minor muscles.
Therefore, we recommend that clinicians should administer the first injection for breast cancer surgery.