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.