Y-Peg-in-a-Round-Hole Closure for Immediate Periareolar Mastectomy Expander Reconstruction.

INTRODUCTION: Mastectomies closed with a linear scar can distort the resulting shape of the breast. We present our novel Y-peg-in-a-round-hole closure method of the mastectomy scar, which improves the shape of the reconstructed breast while maintaining reliable healing, implant coverage, and minimum scar size for covering by tattoo. MATERIALS AND METHODS: A retrospective review of all breast reconstruction cases performed by the senior surgeon during the period from January 2010 to January 2017 was undertaken. Data were analyzed for wound healing problems, infection rates and mastectomy skin flap necrosis. RESULTS: Data were extracted for 126 consecutive patients with 154 breast reconstructions. Twelve breasts (7.7%) experienced wound healing problems, for which 7 (4.5%) required revisionary surgery. Eighteen breasts (11.7%) developed an infection requiring antibiotics, of which 8 (5.2%) needed a further operation. Four breasts (2.6%) needed removal of the implant. No patients were lost to follow-up. CONCLUSION: After nipple resecting mastectomy, the Y-peg-in-a-round-hole scar minimizes radial size and contour deformity but allows for reliable wound healing.

The Deep Inferior Epigastric Perforator Learning Curve in the Current Era.

BACKGROUND: Over the last 2 decades, the deep inferior epigastric perforator (DIEP) flap has gained significant popularity in breast reconstruction. However, for some, the increased technical difficulties associated with DIEP breast reconstruction can be a discouraging factor in adopting this technique. There has been a trend in the literature to acknowledge an acute learning curve in the adoption of DIEP breast reconstruction but little evidence to support its ongoing relevance to surgeons who gain significant exposure in training. METHODS: We test the learning curve concept on the senior author's series of 214 DIEP and superficial inferior epigastric artery flaps in a single-surgeon, retrospective study analyzing chronological trends in complication rates both major (total and partial flap loss, reexploration) and minor (fat necrosis, donor site hernia and bulge). RESULTS: The total complication rate was 7.9%, including 1 (0.5%) partial and 1 (0.5%) total flap failure. A comparison of complication rates in the initial 30 flaps in comparison to the remainder of the series revealed no significant difference in major complications (3.3% vs 3.3%, P = 1.00) or minor complications (6.7% vs 4.3%, P = 0.635). Linear-by-linear analysis performed on chronologically ordered groups of 30 flaps revealed no statistically significant trends over the series. CONCLUSIONS: The learning curve associated with the DIEP is complex and likely relates to competency gained in both technical and decision-making aspects of breast reconstruction. This series has demonstrated that with adequate training and an algorithmic approach to DIEP breast reconstruction, eliminating the early learning curve and improving early outcomes are possible.

Current evidence for postoperative monitoring of microvascular free flaps: a systematic review.

BACKGROUND: Despite a plethora of monitoring techniques reported in the literature, only a small number of studies directly address clinical relevant end points, such as the flap salvage rate and false-positive rate. METHOD: We conducted a systematic review of current evidence regarding the postoperative monitoring of microvascular free-tissue transfer via extensive electronic and manual search and perusing databases, such as PubMed, Cochrane, American College of Physicians (ACP) Journal Club, Cumulative Index of Nursing and Allied Health Literature (CINAHL), Excerpta Medica Database (EMBASE), and Ovid MEDLINE. The included literature (n = 184 publications) was critically appraised using March 2009 Oxford Centre for Evidence-Based Medicine definitions, focusing on the evidence for the efficacy of each technique in improving the flap salvage rate of compromised flaps. RESULT: There is a paucity of outcome-based studies, with only implanted Doppler probes, near-infrared spectroscopy, laser Doppler flowmetry, quantitative fluorimetry, and digital photography assessment using smartphones having been demonstrated in comparative studies to improve flap salvage rate. Currently, the implantable Doppler probe is the technique with the largest number of comparative studies and case series to demonstrate its effectiveness compared with clinical monitoring. CONCLUSIONS: Future studies need to evaluate the most promising monitoring techniques further with a focus on assessing clinically relevant outcomes, such as the flap salvage rate and the false-positive rate, and not simple clinical series reporting patient and physician satisfaction.

Stacked abdominal flap for unilateral breast reconstruction.

BACKGROUND: The abdominal flap can be used in a stacked, double-pedicle configuration for unilateral breast reconstruction. Aided by preoperative mapping, this is a good option when a single-pedicle flap is deemed unsuitable. We present reliable outcomes using the stacked flap and a logical classification system for its use. METHODS: From 2008 to 2013, 18 patients underwent a stacked abdominal flap for unilateral breast reconstruction. Flaps utilized deep inferior epigastric (D) and superficial inferior epigastric (S) pedicle combinations. Preoperative computed tomography angiogram was performed on all patients. Medical records were reviewed for complications and clinical data, and a thorough clinical evaluation was performed on all patients at follow-up. Flaps were all double-pedicled, with the secondary pedicle anastomosed onto the primary pedicle (type 1 to 3) or onto a second recipient vessel (type 4). Flaps were then classified into groups, based on pedicle dominance and intraflap anastomosis. RESULTS: Twelve reconstructions were immediate and six delayed. Mean operative time was 7 hours, the most frequently used configuration being a type 1 DD, that is, secondary pedicle (D) anastomosed end-to-end onto the superior continuation of the primary pedicle (D). Average hospital stay was 6 days. There were no flap losses and minimal complications, and mean follow-up was 20 months. CONCLUSION: Use of this flap poses a greater challenge to the microsurgical breast reconstruction. We demonstrate its reliable use in women deemed unsuitable for a single-pedicle flap. Our structured system clarifies vascular options, and preoperative perforator mapping tools are essential to the success of this technique.

The functional free innervated medial gastrocnemius flap.

BACKGROUND: The functional free innervated medial gastrocnemius flap has been described in four previous articles for the management of foot drop, Volkmann contracture, and upper limb muscle defects. We expand the indications by describing the use of free innervated medial gastrocnemius musculocutaneous flap in functional reconstruction of the tongue and upper limb musculature. METHODS: The right medial gastrocnemius muscles were raised as myocutaneous flaps in six patients. These flaps were elevated in the supine position and the flaps included a motor nerve from the sciatic nerve and a sensory nerve from the sural nerve. The average size of flap was 15 × 8 cm. RESULTS: The flaps were transferred successfully with no flap loss and showed consistent reinnervation during follow-up. In particular, all patients who underwent tongue reconstruction exhibited intelligible speech and returned to full oral diet with no aspiration. In patients who underwent upper limb muscle reconstructions, there was moderate to full restoration of power. All donor sites exhibited excellent symmetry in both power and appearance to the contralateral calf. CONCLUSIONS: To our knowledge, this study is the first to describe the use of the innervated medial gastrocnemius free flap in the reconstruction of the tongue and deltoid. The advantages of this flap include its thin reliable skin paddle, strong bulky bipennate muscle, and low donor site morbidity.

Changes in vascular anatomy following reconstructive surgery: an in vivo angiographic demonstration of the delay phenomenon and venous recanalization.

BACKGROUND: Although a surgical insult may substantially alter local vascular anatomy within tissues, studies that have clearly demonstrated these changes as being dynamic phenomena have not been widely reported. The current study aimed to explore the changes in abdominal wall vasculature after a surgical insult. METHODS: The arterial and venous anatomy of both the deep and superficial epigastric systems of the abdominal wall were explored with computed tomographic angiography (CTA) performed before and after bilateral removal of both bilateral deep and superficial inferior epigastric systems. RESULTS: Several unique anatomic findings were evident, with dilatation of both deep superior epigastric arteries and recanalization of the superficial inferior epigastric veins across the surgical scar, despite previous surgical division. CONCLUSION: The current study demonstrated that there are changes in both major and minor axial vessels and in both the arterial and venous systems after surgical insult. CTA may be of value in identifying these changes prior to surgery utilizing local vasculature.

Functional reconstruction of sarcoma defects utilising innervated free flaps.

Soft-tissue reconstruction following preoperative radiotherapy and wide resection of soft tissue sarcoma remains a challenge. Pedicled and free tissue transfers are an essential part of limb sparing surgery. We report 22 cases of sarcoma treated with radiotherapy and wide excision followed by one-stage innervated free or pedicled musculocutaneous flap transfers. The resection involved the upper limb in 3 cases, the lower limb in 17, and the abdominal wall in 2. The flaps used for the reconstruction were mainly latissimus dorsi and gracilis. The range of motion was restored fully in 14 patients. The muscle strength of the compartment reconstructed was of grades 4 and 5 in all patients except one. The overall function was excellent in all the cases with functional scores of 71.2% in the upper limb and 84% in the lower limb. The only 2 major complications were flap necrosis, both revised with another flap, one of which was innervated with restoration of function. Innervated flaps are valuable alternatives for reconstruction after sarcoma resection in the extremity and in the abdominal wall. The excellent functional results are encouraging, and we believe that innervated muscle reconstruction should be encouraged in the treatment of sarcoma after radiotherapy and wide resection.

Nipple delay prior to nipple-sparing mastectomy: the protective effect on nipple-areola complex ischaemia.

BACKGROUND: Nipple-sparing mastectomy (NSM) has become increasingly popular over the past decade, offering perceived superior cosmetic outcomes and psychological benefits. The main concern in NSM is that of nipple-areola complex (NAC) ischaemia, occurring in up to 15% of cases. We investigate the utility of nipple delay (ND) in protecting the NAC from ischaemic complications. METHODS: A retrospective study of all NSM for a single surgeon from 2010 to 2020 was performed, with those not receiving a prior ND procedure included as a control arm. Variables were recorded, including time to mastectomy from delay, degree of breast ptosis, cup size, mastectomy weight, previous radiotherapy, and presence of ischaemic risk factors. Outcomes recorded were the development of NAC ischaemia, graded from epidermolysis to partial or full-thickness necrosis (FTN). RESULTS: A total of 62 women for a total of 84 breasts were part of the delay cohort. Ten (12%) breasts in the delay group developed ischaemic complications, with only five breasts developing FTN requiring debridement. Moreover, 33 women for a total of 43 breasts were part of the non-delay cohort. A total of 14 (33%) breasts in the non-delay cohort developed ischaemic complications, with six breasts developing FTN requiring debridement. Delay was protective against ischaemic complications with an OR 0.28 (p=0.007). Mastectomy weight of >600 g and >400 g predicted the development of ischaemic complications in the delay and non-delay cohorts, respectively. CONCLUSION: ND was shown to protect against the development of ischaemic complications prior to NSM, with the greatest protective effects shown in those with morphologically large breasts.

Images in plastic surgery: the anatomy of macrovascular arteriovenous shunts and implications for abdominal wall free flaps.

With the increasing use of preoperative imaging of the abdominal vasculature prior to free flaps based on the abdominal wall, the identification of a previously undescribed anatomic structure has, that of large-vessel (macroscopic) arteriovenous communications, has emerged. These macrovascular arteriovenous shunts are observed in most patients, and provide a communication between the arterial perforators of the deep inferior epigastric artery and the superficial inferior epigastric vein. These communications provide vascular shunting occurring prior to capillary filling and have potentially profound clinical implications and therapeutic possibilities in a range of medical and surgical conditions. Although these have been demonstrated previously on computed tomographic angiography imaging, their macroscopic and microscopic anatomy has not been described. We present images in vivo, ex vivo, and histologically to highlight their anatomic features.

Improving the utility and reliability of the deep circumflex iliac artery perforator flap: the use of preoperative planning with CT angiography.

BACKGROUND: The deep circumflex iliac artery (DCIA) is rarely used as a perforator flap, despite a clear clinical need for thin osteocutaneous flaps, particularly in head and neck reconstruction. The poor adoption of such a flap is largely due to a poor understanding of the perforators of the DCIA, despite recent publications demonstrating suitable vascular anatomy of the DCIA perforators, particularly evident with the use of preoperative computed tomographic angiography (CTA). We have applied this method of peroperative imaging to successfully select those patients suitable for the DCIA perforator flap and use it clinically. METHODS: We present a case series of patients who underwent DCIA perforator flap reconstruction following preoperative planning with CTA. Imaging findings, clinical course, and outcomes are presented. RESULTS: Six out of seven patients planned for DCIA perforator flap reconstruction underwent a successful DCIA perforator flap, with imaging findings confirmed at operation, and without any flap loss, hernia, or other significant flap-related morbidities. Because of abberent anatomy and change in defect following excision of pathology, one patient was converted to a free fibular flap. CONCLUSION: With preoperative CTA planning, the DCIA perforator flap is a versatile and feasible flap for reconstruction of the mandible and extremities.

Recurrent phyllodes tumor of the breast: defining the role for skin-sparing mastectomy and autologous reconstruction.

Phyllodes tumors (PTs) are uncommon fibroepithelial tumors of the breast, noteworthy for their difficult excisions and high recurrence rates. In the setting of recurrence, there is no consensus in the literature as to the extent of excision or the impact on reconstructive options. Breast-conserving surgery and simple mastectomy have each been described with mixed reports. Despite a shift toward the selective use of skin-sparing mastectomy and nipple-areola complex-sparing mastectomy in breast carcinoma, neither the role for these techniques nor the role for breast reconstruction in recurrent PT has been described. A case report is presented demonstrating the utility of skin-sparing mastectomy and autologous breast reconstruction for locally recurrent PT of the breast, with a literature review of management options in this setting presented. The case presented highlights an appropriate setting for autologous microsurgical reconstruction of the breast in recurrent PT. The literature review highlights a lack of any published management consensus, with only the role for mastectomy suggested for recurrent high-grade or malignant lesions. A potential management algorithm is thus presented. Skin-sparing mastectomy, particularly for intermediate-grade lesions, may allow wider resections while enabling aesthetically pleasing reconstructive options without affecting recurrence rates.

Case Report: Revisiting the Internal Mammary Artery Perforator Flap: Salvage Option for Circumferential Pharyngo-Esophageal Defects.

Patients that present with pharyngeal strictures and pharyngocutaneous fistulas in the context of previous reconstruction and post-operative radiotherapy often report significant morbidity and reduction in quality of life. Reconstruction of such defects present a substantial clinical challenge requiring the importation of unirradiated vascularized tissue to facilitate healing in a friable, fibrotic, and vessel depleted tissue bed. The authors present a case report demonstrating an adaptation of the internal mammary artery perforator (IMAP) flap for reliable reconstruction of circumferential pharyngeal defects with primary tension free closure of the donor site. This technique avoids the use of free tissue transfer in a hostile, irradiated neck. The tubed IMAP flap is an excellent option, serving the purposes of reconstruction as well as addressing the patient's presenting issues of a chronic sinus and pharyngeal stricture inhibiting oral intake.

The variability of the Superficial Inferior Epigastric Artery (SIEA) and its angiosome: A clinical anatomical study.

INTRODUCTION: The superficial inferior epigastric artery (SIEA) is a useful pedicle in supply to the lower abdominal integument, with its use sparing damage to rectus abdominis muscle or sheath. However, it is limited in usefulness due to its anatomical variability. While previous anatomical studies have been limited in number and study design, the use of preoperative imaging has enabled the analysis of this vasculature in large numbers and greater anatomical detail. METHODS: A clinical anatomical study of 500 hemi-abdominal walls in 250 consecutive patients undergoing preoperative computed tomographic angiography (CTA) prior to autologous breast reconstruction was undertaken. The presence, size, location, and branching pattern of the SIEA were assessed in each case. RESULTS: The SIEA was identified in 468 cases, an incidence of 94%. Its mean diameter was 0.6 mm, and in 24% of cases was of a diameter >1.5 mm. SIEA location was highly variable, with mean position 2-cm lateral to the linea semilunaris (range 0-8 cm lateral), and relationship to the superficial inferior epigastric vein (SIEV) was also highly variable, with the distance between them ranging from 0.3 to 8.5 cm apart. SIEA branches directly crossed the abdominal midline in 5% of cases. Larger SIEA diameters correlated with a decrease in diameter of ipsilateral DIEA perforators. CONCLUSION: The SIEA is present more frequently than previously demonstrated, but is typically too small for use in free tissue transfer. The variable degree of SIEA branching suggests that its territory of supply is also variable, and that preoperative imaging may be useful in planning SIEA flaps.

Modern adjuncts and technologies in microsurgery: an historical and evidence-based review.

BACKGROUND: While modern reconstructive surgery was revolutionized with the introduction of microsurgical techniques, microsurgery itself has seen the introduction of a range of technological aids and modern techniques aiming to improve dissection times, anastomotic times, and overall outcomes. These include improved preoperative planning, anastomotic aides, and earlier detection of complications with higher salvage rates. Despite the potential for substantial impact, many of these techniques have been evaluated in a limited fashion, and the evidence for each has not been universally explored. The purpose of this review was to establish and quantify the evidence for each technique. METHODS: A search of relevant medical databases was performed to identify literature providing evidence for each technology. Levels of evidence were thus accumulated and applied to each technique. RESULTS: There is a relative paucity of evidence for many of the more recent technologies described in the field of microsurgery, with no randomized controlled trials, and most studies in the field comprising case series only. Current evidence-based suggestions include the use of computed tomographic angiography (CTA) for the preoperative planning of perforator flaps, the intraoperative use of a mechanical anastomotic coupling aide (particularly the Unilink® coupler), and postoperative flap monitoring with strict protocols using clinical bedside monitoring and/or the implantable Doppler probe. CONCLUSION: Despite the breadth of technologies introduced into the field of microsurgery, there is substantial variation in the degree of evidence presented for each, suggesting the role for much future research, particularly from emerging technologies such as robotics and modern simulators.

The branching pattern of the deep inferior epigastric artery revisited in-vivo: a new classification based on CT angiography.

The deep inferior epigastric artery (DIEA) is a reliable pedicle in the design of DIEA perforator flaps, with variations in its anatomy infrequent. Previous studies describing its branching pattern have all been based on cadaveric anatomy and described the following three branching patterns: Type 1 (single trunk), Type 2 (bifurcating trunk), and Type 3 (trifurcating trunk). The increased use of preoperative imaging, particularly with computed tomographic angiography (CTA), has enabled visualization of the DIEA and its branches in vivo, providing a functional view of this anatomy. We undertook a study of 250 patients (500 hemiabdominal walls) undergoing preoperative CTA before DIEA perforator flaps for breast reconstruction. The branching pattern of the DIEA and correlation to the contralateral hemiabdominal wall were assessed. The branching patterns of the DIEA were found to be different in vivo compared with cadaveric studies, with a higher than previously reported incidence of Type 1 patterns and lower than reported incidence of Type 3 patterns, and that some patterns exist which were not included within the previous nomenclature (namely, Type 0 or absent DIEA and Type 4 or four-trunk DIEA). There was also shown to be no overall concordance in the branching patterns of the DIEA between contralateral sides of the same abdominal wall; however, there was shown to be a statistically significant concordance in cases of a Type 1 DIEA (51% concordance, P = 0.04). As such, a new modification to the classification system for the branching pattern of the DIEA is presented based on imaging findings.

Anomalies of the flexor carpi ulnaris: clinical case report and cadaveric study.

Flexor carpi ulnaris (FCU) is an ever-present muscle of the anterior flexor compartment of the forearm. Variations of FCU are uncommon, with additional slips or heads of muscles described, and only one reported case of an accessory muscle. We describe a unique clinical case report in which an accessory FCU was identified and describe the findings of 5,000 cadaveric dissections of the forearm, performed as part of an ongoing institutional study of anatomical variations. An aberrant accessory forearm flexor muscle was identified incidentally at the wrist during surgery for an anterior interosseous to ulnar nerve transfer for management of ulnar nerve palsy. This muscle was seen running superficial to the ulnar nerve and radial to the FCU proper, arising from the common flexor origin and inserting at the triquetral carpal bone. This was therefore suitably acknowledged as an "accessory FCU". The anomaly was identified as bilateral using ultrasound imaging, and was found to be anomalously innervated by the median nerve with nerve conduction studies. A subsequent review of 5,000 cadaveric dissections of the forearm did not identify any such variations related to FCU, despite identifying a range of variations of the other forearm flexor musculature. While the scarcity of this anomaly is thus highlighted, consideration of an accessory FCU, and its aberrant innervation is important in a range of surgical approaches.

Dominance between angiosome and perforator territories: a new anatomical model for the design of perforator flaps.

An understanding of the angiosome of a source vessel in supply to a perforator flap is essential to flap design. With substantial interindividual variability in the size and reliability of such territories, preoperative awareness of factors that affect the number or size of perforators in a given territory can aid operative planning. Body weight and scarring are known to modify a given territory, and anecdotally so too can the "dominance" of adjacent vascular territories. A clinical study of 300 patients (600 body sides) was undertaken, using computed tomographic angiography, to map the vessels of six vascular territories. The effect of interplay between vascular territories was assessed by establishing whether a dominant territory was associated with a diminutive adjacent territory. For every vascular territory investigated, the effect of "dominance" was evident, with a statistically significant effect shown between the deep inferior epigastric artery and superficial inferior epigastric artery territories (p < 0.01), and the anteromedial thigh and anterolateral thigh perforator territories (p = 0.01). The size or dominance of perforators in a given vascular territory is influenced by the dominance of adjacent vascular territories. This concept of perforator or angiosome dominance is an important factor in the design of perforator flaps.

Postoperative monitoring of free flaps in autologous breast reconstruction: a multicenter comparison of 398 flaps using clinical monitoring, microdialysis, and the implantable Doppler probe.

Many techniques for flap monitoring following free tissue transfer have been described; however, there is little evidence that any of these techniques allow for greater rates of flap salvage over clinical monitoring alone. We sought to compare three established monitoring techniques across three experienced microsurgical centers in a comparable cohort of patients. A retrospective, matched cohort study of 398 consecutive free flaps in 347 patients undergoing autologous breast reconstruction was undertaken across three institutions during the same 3-year period, with a single form of postoperative monitoring used at each institution: clinical monitoring alone, the Cook-Swartz implantable Doppler probe, or microdialysis. Both objective and subjective measures of efficacy were assessed. Clinical monitoring alone, the implantable Doppler probe, and microdialysis showed statistically similar rates of flap salvage. False-negative rates were also statistically similar (only seen in the clinically monitored group). However, there was a statistically significant increase in false-positive alarms causing needless take-backs to theater in the microdialysis and implantable Doppler arms, P < 0.001. This study did not find any technique superior to clinical monitoring alone. New monitoring technologies should be compared objectively with clinical monitoring as the current standard in postoperative flap monitoring.

Clinical study of peroneal artery perforators with computed tomographic angiography: implications for fibular flap harvest.

PURPOSE: Previous studies of cutaneous perforators of the peroneal artery have shown great variability, and attest to the significant anatomical variability in this region. Furthermore, the vascular anatomy of the region has been considered unreliable in the prediction of ideal perforator topography. Preoperative imaging has been suggested as a means for improving preoperative awareness, with Doppler ultrasound and eco-colour (duplex) ultrasound as useful tools. Multi-detector row computed tomographic angiography (CTA or angio CT), has emerged as a significant improvement, providing non-invasive operator-independent details of the vascular anatomy. We utilised this tool to perform an in vivo, anatomical study of the peroneal artery perforators, and demonstrating the usefulness of CTA in planning the osteocutaneous free fibula flap. METHODS: Forty-one consecutive patients (82 limbs) underwent CTA of the lower limb vasculature, with the anatomical details of the peroneal artery cutaneous perforators assessed. RESULTS: CTA was able to demonstrate the size, course and penetration pattern of all perforators over 0.3 mm in diameter, with measurements for perforators over 0.8 mm diameter recorded for analysis. Of 171 such perforators, accurate identification of the size (mean diameter 1.91 mm), course (59.6% septocutaneous, 29.2% musculocutaneous and 11.1% septomusculocutaneous) and location was achieved. CONCLUSION: The vascular anatomy of peroneal artery perforators is highly variable, and thus there is a role for preoperative imaging. CTA can demonstrate cases where there is aberrant or non-preferred anatomy, or select the limb of choice for harvest.

Intramuscular pathway and fascicular characteristics of the segmental intercostal innervation to rectus abdominis.

BACKGROUND: Rectus abdominis is a muscle that is commonly used clinically as a muscle flap, especially in reconstructive surgery. Its intramuscular innervation, however, has rarely been examined in detail or accurately mapped. The purpose of this study was to use biopsied, histological specimens complemented with a staining technique to investigate intramuscular nerve connections and distribution of the rectus abdominis. METHODS: Four fresh human cadavers were included in the study and rectus abdominis was dissected bilaterally. Nerve sections innervating the rectus abdominis were biopsied and histologically processed. Sections were viewed under the microscope, and axons within each fascicle were counted using imaging software. All specimens were stained with a modified Sihler's staining technique. Intramuscular innervation was observed and the number as well as distribution was recorded. RESULTS: Macroscopically stained specimens showed that the eighth, ninth, 10th and 12th intercostal nerves innervated the eight muscle bellies of rectus abdominis. The greatest number of minor nerve branching as well as intramuscular nerve communications originated from nerve roots T9 and T10. Minor nerve branches crossed tendinous intersections to communicate with adjacent nerves and innervate adjacent muscle bellies. Nerves originating from T9 had the greatest number of nerve fascicles and the highest axon count in each cadaver. CONCLUSION: The rectus abdominis is divided into four compartments with each receiving its own independent nerve supply. Minor nerve branches crossed tendinous intersections to communicate with adjacent muscle bellies and nerves suggesting that rectus abdominis can be used as a whole in innervated free flap transfer procedures.