LICAP Versus TDAP for the Reconstruction of Partial Breast Defects

Perforator flaps are the latest development in reconstructive surgery. Pedicled chest wall perforator flaps can be utilized in many cases of partial breast reconstruction. This research compares the outcome and technique of thoracodorsal artery perforator flap (TDAP) and the lateral intercostal artery perforator flap (LICAP) in the reconstruction of partial breast defects. Patient records were reviewed for the time period between 2011 and 2019 at the Breast Unit of the National Cancer Institute of Cairo University. Eighty three patients were accessible for the study. (46 cases of TDAP flap and 37 cases of LICAP flap). Relevant clinical data were extracted from patients’ records. A special visit was organized for all 83 patients, where a digital photograph was taken in an antroposterior view. The photographs were later processed via BCCT.core software to obtain an objective cosmetic outcome assessment. Complication rates and cosmetic outcome were comparable for both techniques. TDAP flap proved to require more tedious dissection and preoperative Doppler mapping to localize perforator vessels. On the other hand, LICAP was technically easier with more consistent perforators. Pedicled chest wall perforator flaps constitute an excellent reconstructive option in partial breast defects. TDAP flap and LICAP are two reliable perforator flaps which can reconstruct outer breast defects with acceptable outcome.


Background
The surgical management of breast cancer has undergone considerable modifications along time. Breast-conserving surgery is now the standard of care in early-stage breast cancer. In recent years, there have been reports highlighting a survival benefit for breast conservation over mastectomy [1].
In many instances, conservative breast surgery still results in significant defects that might alter the volume and contour and, hence, the aesthetic outcome of the patient. The preservation of an aesthetically pleasing breast is now one of the goals of breast-conserving treatment.
Perforator flaps are the latest development in breast reconstruction. Originally described by Koshima, these flaps are based on branches of main vessels that perforate through the muscle or fascia. The idea behind this technique is to reduce donor site morbidity to an absolute minimum by keeping the muscles with their main blood supply in place [2]. This concept has revolutionized the field of reconstruction in general. For breast reconstruction, there are two types of perforator flaps at hand: the free and the pedicled perforator flaps.
Free perforator flaps have anatomically distant donor sites such as the abdominal wall. Based on deep or superficial inferior epigastric perforator vessels (DIEP, SIEP), these flaps require microvascular anastomosis to one of the main vessels supplying the breast (usually internal thoracic vessels). Another example are the superior gluteal and inferior gluteal perforator flaps (SGAP, IGAP).
Pedicled perforator flaps are based on branches of vessels in the vicinity of the breast. Thoracodorsal artery perforator flap (TDAP) is based on perforating vessels of the longitudinal (lateral) terminal branch of the thoracodorsal artery. These vessels perforate through the latissimus dorsi muscle to share in the blood supply of the skin over the back and lateral part of chest wall. The lateral intercostal artery perforator flap (LICAP) relies on the lateral perforating vessels of the 6-8th intercostal vessels which perforate the intercostal muscles and serratus anterior to supply the skin of the lateral part of the chest wall.
Both flaps (TDAP and LICAP) are indicated for the reconstruction of partial breast defects involving the lateral aspects of the breast. This research compares the technicalities and outcome of both techniques.

Methods
This is a retrospective non-randomized study comparing the outcome and technical aspects of the TDAP and the LICAP for the reconstruction of partial breast defects.
Both techniques have been performed at different time frames at the same institution (National Cancer Institute of Cairo University) by the same surgical team. Indications were similar in both study groups, namely: Relevant clinical data were extracted from patients' records. A special visit was organized for all 83 patients, where a digital photograph was taken in an antroposterior view.
The photographs were analysed using the Breast Cancer Conservative Treatment cosmetic results (BCCT.core©) software. The BCCT software provides a 4-point classification scale (excellent, good, fair and poor) to determine the overall assessment of cosmetic outcome. Several cosmetic parameters in the photograph are automatically evaluated by the software, such as scar visibility and symmetry among other measurements to produce a final cosmetic result.
Results of both groups were recorded in tables, and data were statistically described in terms of mean ± standard deviation (± SD) and/or frequencies (number of cases) and percentages when appropriate.
Comparison of numerical variables between the study groups was done using the Student t test for independent samples in normally distributed data and Mann-Whitney U test for independent samples in not normal data. For comparing categorical data, chi square (χ 2 ) test was performed. Exact test was used instead when the expected frequency is less than 5. p values less than 0.05 was considered statistically significant. All statistical calculations were done using computer program SPSS (Statistical Package for the Social Science; SPSS Inc., Chicago, IL, USA) release 15 for Microsoft Windows (2006).

Patients
The demographic data and comorbidities of the study groups are illustrated in Table 1.
The clinical TNM stage for the study groups at initial presentation is illustrated in Table 2.
Six patients of the TDAP group and three patients of the LICAP group received neoadjuvant chemotherapy for downstaging to enable breast conservation.
All patients in both groups underwent preoperative Doppler mapping to allocate the site of perforators preoperatively. In addition, intraoperative frozen section examination was done for all specimens in order to verify negative margins of excision before flap elevation was started.

Results
The mean operative time for TDAP was 229 min (range 310-180), while that of LICAP was 176 min (range 220-166). Average TDAP flap dimensions were 18 × 9 cm (range length 14-21 cm, range width 7-12 cm). The  average size of the flaps harvested in the LICAP group was 21 × 11 cm (range length 17-23, range width 10-13 cm). A well-developed isolated perforator vessel could be identified and adequately dissected as a pedicle in 3 patients of the TDAP group and in 7 patients of the LICAP group. In the rest of TDAP cases, a piece of latissimus dorsi muscle was harvested around the perforator vessels, while in the LICAP group, a mesentery of subcutaneous fat was maintained around the perforators (Fig. 1).
Preoperative Doppler mapping for TDAP showed that one or two perforator vessels are present in 80% of cases in a quadrant formed through the intersection of four lines: two horizontal lines 9 cm and 11 cm downward from the level of the posterior axillary fold with the arm abducted 90° and two vertical lines 1 and 4 cm medial to the anterior border of latissimus dorsi muscle (Fig. 2).
In the LICAP group, a perforator or two were detected preoperatively in all cases at the medial lower angle of a triangle formed by the anterior and posterior axillary lines with its base formed by a horizontal line at the level of the inframammary fold (Fig. 3).
Intraoperatively, the Doppler mapping proved accurate in 87% of cases of TDAP and 100% of LICAP group.
Complications occurred in 8 patients in the TDAP group (17.4%). The most common complication was venous congestion that occurred in four patients. The condition was completely reversible within 48 h in three patients and progressed to superficial sloughing in one patient. There were two cases of minor wound infection at the recipient site that responded to repeated dressing. One patient suffered a postoperative hematoma that was surgically evacuated. Another case presented with fat necrosis The complication rate was 11% in the LICAP group. Two patients presented with seroma, one in the axilla and one in the breast. Another two patients presented with minor wound infection at the recipient site.
The results of both study groups are summarized in Table 3.

Discussion
The concept of perforator flaps has brought about significant enhancements to the field of breast reconstruction.  [6]. This research illustrates the experience of a single surgical team with two chest wall perforator flaps described for partial breast reconstruction.
The TDAP flap has proven to be more tedious and in need of a steep learning curve to master. Its most common  complication in this limited experience was venous congestion. The perforators for this flap are seemingly not consistent and might lie in some cases outside the anatomical boundaries described for them. It is advisable to perform preoperative Doppler mapping, whenever a TDAP flap is planned.
On the other hand, LICAP flaps are a very easy to learn technique with many possible ways to fashion the skin paddles and several possible arcs of rotation. This versatile flap could be based on the lateral thoracic pedicle (LTAP) or the lateral intercostal perforators.
The lateral intercostal perforators to the skin of the chest wall are apparently very consistent in their anatomical location and more abundant than in case of the TDAP. According to our limited experience, intercostal perforators were always found at the lower anterior angle of a triangle bounded by the anterior axillary line, the posterior axillary line and the inframammary fold.
On the other hand, the skin perforators of the TDAP flap were not easily detected. The usual technique of TDAP flap harvest is to rely on one of the two terminal branches of the thoracodorsal pedicle without tracing the isolated perforators through the muscle. Another option is to harvest a piece of muscle around the perforators (a muscle sparing technique) such as the technique adopted in this study. In this research, the only point of comparison that reached a statistical significance was the location of perforators. Still, this result might be a subject to bias due to inconsistent measurements. Further anatomical studies are needed to verify this difference between the surface anatomy of the perforators of LICAP and TDAP.
The surgical management of breast cancer has witnessed a noticeable de-escalation from total mastectomies to more limited resections. The resulting defects were initially managed by latissimus dorsi miniflaps [7]. This technique, however, still left behind significant donor site morbidity. Perforator flaps have emerged as a very suitable reconstructive option in these cases with very limited donor site morbidity. These flaps are optimal in patients where considerable volume resections are planned, but still a mastectomy is not indicated.

Conclusion
Pedicled perforator flaps combine the best of two worlds. They retain the major advantage of perforator flaps by leaving behind minimal donor site morbidity while maintaining a reliable pedicle. According to this limited experience, it is now the technique of choice whenever a partial breast defect is considered for reconstruction. Musculocutaneous flaps form no longer an acceptable option in these cases. The ease and practicality of chest wall perforator flaps as well as their minimal morbidities have brought them to the front lines in partial breast reconstruction.
Author Contribution TH arranged for statistical analysis and pathological information. SNT and AO were responsible for data collection and organization and collaborated with TH in writing the final manuscript. The authors have all read and approved this final manuscript.
Data Availability Please contact the author for data request.

Declarations
Ethics Approval and Consent to Participate The study was done after the approval of the ethical committee of the National Cancer Institute of Cairo University.

Consent for Publication
Consent for publication was obtained from patients.

Competing Interests
The authors declare no competing interests.