The Reverse Dual Plane: A Novel Technique for Endoscopic Transaxillary Breast Augmentation

Abstract Background Quite a few Asian patients prefer axillary incision for breast augmentation. However, this surgery needs improvement. Objectives To introduce a reverse dual-plane technique through a transaxillary approach and compare it with a transaxillary dual-plane approach. Methods Eighty-two patients were divided into Group A (n = 40) and Group B (n = 42). Axillary incision and endoscope were utilized in the 2 groups. Tebbetts’ dual plane was performed in Group A patients. Patients in Group B underwent our reverse dual-plane technique, in which the upper 70% was subfascial and the lower 30% was subpectoral, with the fascia of the external oblique and anterior serratus being elevated together with the pectoral muscle. The Numeric Pain Rating Scale (NPRS) scores were recorded daily for 7 days. Breast shape and softness, in both sitting and supine positions, were assessed by the patients, and complications were compared. Results The NPRS scores of Group B patients were significantly lower than those of Group A patients (P < .01). The satisfaction rate of shape and softness in the seated position was not significantly different (P > .05). However, in the supine position, only 20 patients (50.0%) in Group A and 32 patients (76.2%) in Group B were satisfied with their breast softness (P < .01), and the breasts of the others became stiffer. Breast animation deformity (BAD) occurred in 2 patients in Group A and in no patient in Group B (P < .01). Other complications were not significantly different. Conclusions Compared with Tebbetts’ dual plane, this procedure significantly reduced pain, improved breast softness, and eliminated BAD, without increasing complications. Level of Evidence: 4

palpability, rippling, and implant malposition occurred occasionally. 1,4In recent years, some of our patients have been complaining over the phone that their breasts were firming.We asked them to get readmitted to the hospital, after which we found that their breast softness was normal.However, they said that their breasts were still soft when sitting or standing, but they became hard when lying on the back.Therefore, we reexamined their breasts in the supine position, and we found that the supine position did have harder breasts than the seated position.Based on our observations, among patients who did not have this complaint, there were also varying degrees of difference in breast softness between the seated and the supine positions.4][15] Unfortunately, the complaint has been neglected by surgeons to such an extent that there are no reports in the literature on this subject.All of these suggest that implant breast augmentation needs further improvement.
7][18] They worry that the symmetric scar on the breasts makes them less attractive.A fair number of patients in Asia prefer axillary incision for breast augmentation.To respect such patient choices, Tebbetts' dual-plane technique through a transaxillary approach has been performed by many surgeons, especially Asian surgeons, following which there has been a significant improvement in results. 2,16,179][20] The transaxillary endoscopic procedure still leaves plenty of room for improvement.Therefore, in this study, we introduce our novel reverse dual-plane axillary endoscopic breast technique and compare it with the more traditional transaxillary dualplane technique for achieving patient satisfaction.

METHODS
A total of 82 patients with a mean age of 35 years (range, 20-52 years) were included in this study from October 2018 to May 2022.The inclusion criteria were primary implantation augmentation, preferably through an axillary incision, with a pinch thickness >1.0 cm.These patients were divided into Tebbetts' dual-plane group (Group A, n = 40) and our modified dual-plane group (Group B, n = 42).Randomization was based on the order of operations, with odd numbers assigned to Group A and even numbers to Group B. This study was approved by the ethics committee of Chongqing Vcharm Plastic Surgery Hospital, and all patients had signed consent forms for surgery.All operations utilized axillary incisions with endoscopic assistance, and all were performed under endotracheal intubation and intravenous anesthesia.In Group A patients, the implant pockets were formed as Tebbetts' Type I and Type II dual planes. 2 The dissection was subpectoral from the entrance to the new IMF, with the fascia of the anterior serratus and external oblique elevated together with the pectoral muscle.Then, the pectoral muscle was resected at a different level, according to the degree of the breast ptosis (Video 1).
The patients in Group B were operated upon utilizing our reverse dual-plane technique, in which the dissection started beneath the fascia of the pectoral muscle.When the dissection reached the fifth rib, the pectoral muscle was cut in an inclined plane with an electrotome, and then the dissection went gradually deeper under the pectoral muscle, with the fascia of the external oblique and anterior serratus being elevated together.The dissection was completed at the new IMF.If the new IMF was lowered, the dissection was continued under the rectus abdominus muscle fascia.In this manner, a novel dual-plane pocket was formed (Figures 1, 2, Video 2).
Before implant insertion, 2% lidocaine + 0.75% ropivacaine were utilized to block the intercostal nerve in both groups to relieve postoperative pain.We utilized either round or anatomical microtextured implants from Mentor (SILTEX Round Gel Breast Implant, CPG, Mentor Medical Systems BV, Leiden, the Netherlands).Implant insertion sleeves were not utilized.After placement, the upper part of the implant (accounting for ∼70% of its height) was subfascial, and its lower pole was the subpectoral muscle and subfascial of the external oblique and anterior serratus (accounting for ∼30% of the height of the implant) in Group B (Figure 1).Negative pressure drainage was maintained for 24 to 72 h, and cefazolin and levofloxacin were administered intravenously for 2 days for both groups.
From the operative day (POD0) to postoperative Day 7 (POD7), pain scores were recorded daily by the patients utilizing the Numeric Pain Rating Scale (NPRS).On the NPRS, the patients rated their pain quantitatively on a Likert scale from 0 (no pain) to 10 (worst pain).The NPRS scores were compared between Group A and Group B. Statistical analysis was performed utilizing a t-test.
All patients were followed up for at least 18 months after surgery (Table 1).During the follow-up period, breast shape and softness were assessed by the patients, who were reminded to compare their breast softness in both the supine and sitting positions.The patients were asked to fill out the satisfaction questionnaires (Table 2) about various outcomes by themselves, including static and dynamic breast shape, softness, surgical scars, effects on physical labor or exercise, and breastfeeding function.At the same time, any complications, including breast animation deformity (BAD), capsular contracture, implant palpability and malposition, and rippling breast, were assessed by the surgeons.Statistical analysis was performed by using the χ 2 test.

RESULTS
Basic information about the patients, including their mean age, mean prosthesis volume, and the average follow-up time (Group A = 26.5 months, Group B = 25.9 months), is provided in Table 1.The breast shape after surgery is shown in Figures 3-5.

Postoperative Pain
From POD0 to POD7, the NPRS scores of Group B patients were significantly lower than those of Group A patients (Table 3).

Breast Softness in a Different Position
Altogether, 80 patients (80/82, 97.6%) in the 2 groups were satisfied with the softness of their breasts in the sitting or standing position.In Group A, 20 cases (40 sides, 50.0%) of the breasts were significantly harder in the supine position than in the sitting position.However, in Group B, only 10 patients (20 sides, 23.8%) had worse breast softness in the supine position.This difference was significant (P < .001;Table 4), which meant that 76.2% of patients in Group B felt no difference in breast softness between the supine and the seated positions.

Complications After Surgery
There were no hematomas and infections among the patients in the 2 groups.Baker Grade III capsular contracture occurred on 1 side in 1 patient in Group A (her right breast   was firm from the 1st month to the 25th month after surgery) and on both sides in 1 patient in Group B (her breasts were firm from the 3rd month after operation).Both these patients required a revision surgery.There were 2 patients with animation deformity in Group A and none in Group B (P < .01).Five patients in Group A and 6 in Group B complained of implant palpability (P > .05).There was no significant difference between the 2 groups.The postoperative complications are provided in Table 5.

DISCUSSION
Pain management has always been a very important aspect of breast augmentation surgery, which largely determines the length of recovery.Some people who want to have this surgery do not have it just because they feel that the pain after the surgery is severe. 6,8,11The degree of pain is closely related to the plane for implant placement. 10,19The traditional axillary approach with the implants beneath the pectoral major muscle is the most painful because of the large subpectoral dissection area and the high tension of the muscle due to implant insertion.In fact, the pain is mainly due to the implant under the intact pectoral muscle resulting in a significant increase in muscle tension, which is called "tension pain." 10,11Tebbetts' dual-plane technique alleviates postoperative pain because it partially releases the tension on the pectoral muscle. 1,2However, the release of this tension is not complete.Most of the pectoral muscle is still held tight by the implant, and hence, patients have also complained about this pain. 7,124][5] Generally, the pinch thickness should be ≥20 mm; otherwise, implant palpability (especially in the lower pole) and ripples are common complaints. 5By combining the subfascial and submuscular planes, our modified technique completely released the tension of the pectoral muscle with the least amount of submuscular dissection.A part of the elevated pectoral muscle is completely separated from the part left in situ, and the tension release is complete; thus, the degree of postoperative pain is significantly reduced and BAD is eliminated.Some surgeons also believe that after subfascial or subglandular plane surgery, mastoptosis may increase, the areola may enlarge, and the incidence of implant palpability may increase due to the lack of support by the pectoral muscle. 19,20Our procedure had the lower pole of the implant (which accounts for ∼30% of the implant's height) subpectoral and beneath the fasciae of the external oblique and the anterior serratus.This reverse dual plane ensures the thickness and supports the strength of the soft tissue that covers the lower pole of the implants. 21,22][21][22] After surgery, most patients are satisfied with the softness of their breasts in the sitting position.However, when they lie in the supine position, their breasts usually become harder.][15][16] This result was confirmed in the last 6 years of follow-up with our patients.It is likely that most patients have not had to pay minute attention to their breasts, or that most surgeons have ignored it, and thus, we have not followed the literature in this regard to date.In a word, this phenomenon is an objective existence, we should come up with solutions. 14,152][23] To solve this problem, implant placement plane and muscle tension release remain important.Our modified procedure made the upper and lower parts of the pectoral muscle to separate completely, with the upper part of the pectoral muscle being in situ.The tension of the pectoral muscle was completely released and the compression on the implants relieved.In Group A, only 50% of the patients felt no significant difference in the softness of their breasts between the supine and the seated positions.This meant that 50% of the patients felt that their breasts became harder in the supine position.In Group B, only 23.8% of the patients felt so, whereas the rest (76.2%) felt no significant difference in the different positions.When performing this procedure, it is necessary to pay attention to the following details.First, when dissecting to the fifth rib, it must be ensured that the pectoralis major muscle is not cut perpendicular to the muscle surface, but rather is cut into a bevel from shallow to deep, so that the step deformity in the lower pole of the breast can be avoided after surgery.Second, attention should be paid to reserve the superficial branch of the intercostal nerve (especially the fourth intercostal nerve) during the dissection near the anterior axillary line and to protect the anterior recurrent branch of the intercostal nerve during the dissection near the parasternal line.Our method is to change sharp dissection to blunt dissection when it is close to the nerve.It should be added that this modified method is also feasible and applicable to both areolar and IMF incisions.We have performed this modified method on many patients through areolar and IMF incisions and will continue to share it in the future.
Finally, this study showed that our modification procedure significantly reduced postoperative pain, improved breast softness in the supine position, and rendered patients free from BAD.Our study had also some limitations such as the lack of quantitative evaluations of breast softness; thus, our modified procedure needs to be performed more frequently.

CONCLUSIONS
Compared with Tebbetts' dual-plane technique, our modified technique has a significant effect on relieving postoperative pain and improving breast softness in the supine position.In addition, it does not result in animation deformity and does not lead to an increase in other complications.The indications of the procedure and the need to evaluate breast softness quantitatively remain important and require further analysis.

Figure 2 .Video 2 .
Figure 2. Pocket formation.(A) Subfascial dissection was performed from the entrance to the fifth rib level.(B) Dissection tuned to the submuscular plane with the fascia of the external oblique and anterior serratus elevated.(C) Postdissection.*Fasciae of the pectoral muscle.**The pectoral muscle.***Electric cutter.****Rib.

Figure 3 .Figure
Figure 3.A 31-year-old female presented with a 1.4 cm thickness of soft tissue on the lower quadrant.Through an axillary incision with endoscopic assistance, 335 cc/332 CPG gel implants were inserted in the modified pockets.(A) and (C) show the patient before surgery, and (B) and (D) show the patient 33 months after surgery.

Figure 5 .
Figure 5.A 37-year-old female presented with a 1.2 cm thickness of soft tissue on the lower quadrant.Through an axillary incision with a modified plane, 255 cc/322 CPG gel implants were utilized.(A) and (C) show the patient before surgery, and (B) and (D) show the patient 19 months after surgery.

Table 1 .
Basic Information About the Patients in Groups A and B LFUD, least follow-up duration; MA, mean age; MFUD, mean follow-up duration; MVI, mean volume of implants.

Table 2 .
Satisfaction Questionnaire After Implant Breast Augmentation Surgery

Table 4 .
Incidence of Breast Softness Changes From the Sitting to Supine Positions in Groups A and B *P < .001,its value obtained in a χ 2 test.

Table 5 .
Incidence of Complications in Groups A and B

Table 3 .
Postoperative the Numeric Pain Rating Scale (NPRS) Scores in Groups A and B *P < .01,its value obtained in a 2-sampled t-test.