Materials and methods
Clinical data
A retrospective analysis was conducted on the clinical data of patients who underwent single-port axillary endoscopic breast cancer radical resection with implant-based reconstruction involving pectoralis muscle at Ningxia Medical University General Hospital from August 2020 to March 2023. A total of 57 patient data were collected, and 5 patients with incomplete clinical data were excluded. Analysis was performed on 52 female patients with a mean age of (42.23 ± 8.28) years (range: 25-59 years) and a mean body mass index of (23.16 ± 2.93) kg/m2 (range: 17.31-29.32 kg/m2). The tumor diameter was (2.08 ± 1.13) cm (range: 0.5-5.3 cm), and the TNM stages were as follows: stage 0 in 6 cases, stage I in 20 cases, stage II in 19 cases, and stage III in 7 cases. Axillary lymph node dissection was performed in 26 cases, with an average of (18.77 ± 5.32) lymph nodes removed (range: 11-28 nodes); sentinel lymph node biopsy was performed in 25 cases, with an average of (4.48 ± 1.59) lymph nodes collected (range: 2-8 nodes) (Table 1); 1 patient (with in situ carcinoma) did not undergo lymph node biopsy.
2.Surgical methods
2.1.Inclusion criteria: (1) Age between 20 and 65 years old; (2) Tumor maximum diameter ≤5.0 cm, or tumor maximum diameter ≤5.0 cm after neoadjuvant chemotherapy; (3) Preoperative magnetic resonance imaging shows no invasion of the nipple-areola complex, skin, or pectoralis major muscle; (4) No distant metastasis found before surgery; (5) Preoperative core needle biopsy confirms breast malignant tumor; (6) Eastern Cooperative Oncology Group performance status score 0-2; (7) Patients have the willingness for breast reconstruction.
2.2.Exclusion criteria: (1) Large breast volume or significant sagging, which cannot provide sufficient breast volume or relatively symmetrical appearance through simple implantation; (2) Preoperative examination or intraoperative rapid pathological examination shows tumor invasion of the nipple-areola complex, skin, or pectoralis major muscle; (3) Clinical stage IIIB or later tumor before surgery; (4) Positive surgical margin during surgery.
2.3.Selection of implants: The type and size of the implant are selected based on the patient’s breast and tumor size and personal preferences. The size of the implant is determined using the radial measurement method. (1) Use a caliper to measure the distance from 1.5-2.0 cm beside the midline to the anterior axillary line, which is the maximum basal diameter (X) of the breast. Use the same method to measure the thickness of the outer soft tissue (Y) and inner soft tissue (Z) of the breast. Calculate the basal diameter of the implant as X - (Y/2 + Z/2). (2) In addition to determining the basal diameter of the implant, anatomical implants also require the selection of implant height (low, medium, full, or extra-full). Use the distance from the sternal notch midpoint to the nipple as SN and the distance between the nipples as NN. If (SN-NN) is 0-2 cm, select a medium-height implant. If (SN-NN) is <0, indicating outward nipple deviation, select a low-height implant. If (SN-NN) is >2 cm, indicating inward nipple deviation, select a full or extra-full implant. (3) Determine the convexity of the implant according to the reconstruction needs. Full convex implants are used in breasts with significant sagging or skin laxity or when a larger implant volume is desired; otherwise, medium or low convex implants are used. Unlike traditional open implantation breast reconstruction surgery, the tension zone caused by the incision being far away from the implant in the endoscopic implantation breast reconstruction surgery does not require reducing the convexity or volume of the implant.
2.4.Surgical Procedure
The eight-step surgical operation:
1)Sentinel lymph node biopsy: General anesthesia with endotracheal intubation, supine position, shoulder and back elevated by 25°, the affected limb is abducted by 60° (Figure 1). Ten minutes before surgery, subcutaneously inject 2 ml of methylene blue into the nipple-areola complex of the affected side. Make a hidden incision in the axillary fold, cut open to the subcutaneous tissue, and perform a sentinel lymph node biopsy at the outer edge of the pectoralis major muscle. If it is positive, perform axillary lymph node dissection. Preliminary separation of the breast posterior space and the pectoralis major muscle posterior space is performed to create a space for endoscopic operation. (Video 1)
2)Separation of the posterior intercostal muscles: A 7.5cm or 10cm incision protector is inserted through the axillary incision, and a rolled-up size 6.5 glove is placed inside the protector. The thumb, middle finger, and little finger of the glove are each placed into 5mm, 5mm, and 12mm puncture devices and inserted into the operating equipment (Figure 2). The index finger is inserted into a suction catheter as a means of preventing smoke interference during the operation. CO2 pressure is used to maintain the cavity, with a pressure of 10-12mmHg. An ultrasonic knife is used to gradually separate the posterior intercostal muscles, cutting the chest muscles at the 3-5 rib points. Muscle cutting points must be cut in place to prevent muscle tension from causing tearing and bleeding. (Video 2)
3)Separation of the posterior breast gap: The posterior breast gap is generally a loose gap and can be separated using an electric knife or ultrasonic knife. It extends from the sternum to the breast margin, and from the edge of the breast to 1-2cm below the crease of the breast. During the separation of the posterior breast gap, the separation speed should be slowed down when approaching the inner edge of the rib to prevent unexpected bleeding. (Video 3)
4)Separation of subcutaneous tissue using the tissue scissors tunnel method: First, inject 100-150ml of swelling fluid subcutaneously (containing 1:500,000 adrenaline and 20ml of lidocaine hydrochloride). Since the blood vessels from the intercostal space have already been dealt with in the previous two steps, there is very little chance of subcutaneous bleeding, so we choose to use tissue scissors to separate the subcutaneous tissue. Use tissue scissors to create four subcutaneous tunnels and expand the tunnels using the outer expansion force of the scissor head. Along the established tunnel, use the tissue scissors to sharply separate the subcutaneous tissue to 0.5-1cm inside the glandular edge, including the tissue below the nipple and areola. (Video 4)
5)Complete removal of breast glands under laparoscopy: Since the front and back of the gland have been processed in advance, after the laparoscope is inserted, only a small amount of the gland around the gland can be seen. Use an ultrasonic knife to cut and separate along the natural arc caused by CO2 pressure and completely remove the gland. Thoroughly stop bleeding and rinse the wound with 1000ml of distilled water at 42°C. Tissue samples are collected from four points of the nipple-areola complex and sent for rapid pathology during the surgery, confirming that there is no tumor invasion in the nipple-areola complex. (Video 5)
6)Cutting the lower and inner edges of the pectoralis major: The anterior and posterior gaps of the pectoralis major have been completely separated, and the outer edge is already in a free state. Use an ultrasonic knife to cut along the lower edge of the pectoralis major towards the inner edge, and cut the inner edge to the fourth rib. (Video 6)
7)Suturing and patching: Fold the patch in half and flip the lower edge up. Pre-stitch the upper edge of the patch with 3-0 Vicryl suture. Insert the patch along the free edge of the pectoralis major and flatten it. Continuously suture the patch to the lower edge and inner free edge of the pectoralis major. (Video 7)
8)Wrapping the prosthesis with a downward flap patch: Insert the prosthesis under the patch and wrap it with a downward flap patch. The specific method is as follows: First, use an oval clamp to push the outer patch towards the back and upper part of the prosthesis to complete the outer prosthesis wrapping. Along the edge of the outer prosthesis wrapping, push the lower patch towards the inner upper part repeatedly until the patch completely wraps the prosthesis. Compare both sides and perform shaping. Place a 15# high negative pressure drainage tube in the axilla and below the crease of the breast on each side. (Video 8)
2.5.Perioperative Antibiotic Management: One dose of intravenous antibiotics is administered 30 minutes before surgery, with an additional dose given if the surgery lasts more than 3 hours, and another dose given 6 hours after surgery.
3.Observational Indicators:
Record the surgical time, length of hospital stay and costs, drain output 2 days post-surgery, body mass index, tumor size, etc. Record and evaluate postoperative outcomes, including incision infection, skin necrosis, incision dehiscence, implant removal, and patient satisfaction score after reconstruction.
4.Postoperative Follow-up
Postoperative regular outpatient follow-up is conducted every 3 months, including guidance on comprehensive treatment, assessing patient compliance with treatment, checking for recurrence or distant metastasis, and evaluating breast appearance. Physical examination and ultrasound are performed based on the patient’s condition, and PET-CT and other examinations are performed for suspected metastases. A satisfaction evaluation form is developed based on the partial content of the Breast-Q scale, and patient satisfaction with breast appearance and cosmetic effects is surveyed.
5.Statistical Methods
SPSS 19.0 statistical software is used for data analysis. Normally distributed quantitative data are expressed as ±s, and t-tests are used for intergroup comparisons. Non-normally distributed quantitative data are expressed as M (QR), and the Mann-Whitney U test is used for intergroup comparisons. Categorical data are expressed as frequency and percentage, and the chi-square test is used for unordered categorical data, while the Wilcoxon rank-sum test is used for ordered categorical data. Differences with P<0.05 are considered statistically significant.