Jeannette W.C. Ting

Superior and inferior gluteal artery perforators: In-vivo anatomical study and planning for breast reconstruction

BACKGROUND Gluteal artery perforator (GAP) flaps have gained popularity in autologous breast reconstruction, however substantial variability in vascular anatomy has limited their more widespread utilisation. While previous anatomical studies have been limited by specimen numbers and study design, computed tomographic angiography (CTA) can demonstrate in-vivo vascular anatomy in large numbers. We thus undertook an anatomical study with the use of CTA, the largest such study in the literature, and present a clinical series utilising CTA to plan GAP flaps. METHODS Eighty consecutive patients (160 gluteal regions) underwent pre-operative CTA, with superior and inferior gluteal artery perforators (SGAPs and IGAPs) assessed for location, size and course. The utility of pre-operative CTA is explored in a series of seven consecutive patients undergoing autologous breast reconstruction. RESULTS There were an average of 11 SGAPs per region (range 6-17), with mean diameter 0.6mm (range 0.3-2.4) and SGAPs >0.8mm diameter identified in every region. In contrast, there were nine IGAPs per region (range 5-14), with mean diameter 0.4mm (range 0.3-1.6) and IGAPs >0.8mm diameter identified in 95% of regions. Individual SGAP and IGAP territories were different between sides and between individuals, with the central tissue variably supplied by either system. In a clinical series, CTA was found to aid operative planning and correlate with operative findings. CONCLUSION There are regularly abundant SGAPs and IGAPs identifiable per gluteal region, and while many are diminutive in size, the identification of suitable perforators with CTA may aid operative planning for gluteal flap harvest.

The in vivo anatomy of the deep circumflex iliac artery perforators: defining the role for the DCIA perforator flap.

The deep circumflex iliac artery (DCIA) provides a dependable option for use as an osteo‐musculo‐cutaneous flap, particularly in mandibular reconstruction. Modifications to flaps based on DCIA perforators have been sought to prevent donor site morbidity as a consequence of muscle cuff harvest. Previous studies have been inconsistent in their descriptions of perforator anatomy, and means of assessing these preoperatively have not been widely described. A clinical anatomical study was undertaken, with a cohort of 44 hemiabdominal walls in 22 consecutive patients undergoing preoperative computed tomographic angiography (CTA) before free flap surgery. The feasibility of CTA and the regional vascular anatomy were both assessed. The use of CTA was shown to demonstrate DCIA perforators with high resolution and to be able to assess vessel size and location. In 44 hemiabdominal walls, there were 44 perforators of >0.8 mm diameter. There were no suitable perforators in 40% of sides, with 32% of sides having one perforator >0.8 mm diameter, 16% having two perforators, <10% had three perforators, and only one side had over four perforators. Perforators emerged from the deep fascia on an average of 5.1 cm cranial and 3.9 cm posterior to the anterior superior iliac spine (ASIS). Of the 44 perforators identified, 82% of perforators were located within a 4 cm by 4 cm area, 3 cm superior, and 2 cm posterior to the ASIS. The current study has demonstrated the utility of preoperative CTA for identifying DCIA perforators, and for selecting patients who may be suitable for a DCIA perforator flap given the variable perforator anatomy.

Total scalp reconstruction with bilateral anterolateral thigh flaps

Large scalp defects can require complicated options for reconstruction, often only achieved with free flaps. In some cases, even a single free flap may not suffice. We review the literature for options in the coverage of all reported large scalp defects, and report a unique case in which total scalp reconstruction was required. In this case, two anterolateral thigh (ALT) flaps were used to resurface a large scalp and defect, covering a total of 743 cm2. The defect occurred after resection and radiotherapy for desmoplastic melanoma, with several failed skin grafts and local flaps and osteoradionecrosis involving both inner and outer tables of the skull. The reconstruction was achieved as a single‐stage reconstruction and involved wide resection of cranium and overlying soft‐tissues and reconstruction with calcium phosphate bone graft substitute, titanium mesh, and two large ALT flaps. The reconstruction was successfully achieved, with minor postoperative complications including tip necrosis of one of the flaps and wound breakdown at one of the donor sites. This is the first reported case of two large ALT flaps for scalp resurfacing and may be the largest reported scalp defect to be completely resurfaced by free flaps. The useof bilateral ALT flaps can be a viable option for the reconstruction of large and/or complicated scalp defects.

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.

Predictors of blood transfusion in deep inferior epigastric artery perforator flap breast reconstruction.

Perioperative blood loss during and following breast reconstruction surgery can have substantial impact on free flap survival and patient morbidity. Transfusion rates of up to 95% have been reported following transverse rectus abdominis myocutaneous flap breast reconstruction, with blood loss described as significant in most cases. However, there has been little reported of such requirements in patients undergoing deep inferior epigastric perforator (DIEP) flap breast reconstruction. We present the transfusion requirements of 152 consecutive patients who underwent DIEP flap breast reconstruction, with a view to quantifying transfusion requirements and identifying risk factors for such loss. In this cohort, 80.3% of patients required blood transfusion, with a mean volume of 3.9 U per patient. There was a statistically significant correlation for increased transfusion requirement in patients with preoperative anemia ( P < 0.001) and in bilateral cases ( P < 0.001), but not for cases of immediate reconstruction ( P = 0.72). Although blood loss in breast reconstructive surgery is rarely large enough to be life-threatening, relative anemia does have significant effect on flap survival and patient morbidity. With risk factors for increased transfusion requirements identified in the current study, high-risk patients can be predicted preoperatively.

The nomenclature of venous flow‐through flaps: Updated classification and review of the literature

Venous flow‐through flaps (venous flaps) are useful reconstructive options, particularly in the repair of defects with segmental vessel loss. They are relatively easy to harvest and confer several benefits at the donor site. However, given that they are based on a single central vein, their survival is notoriously unreliable and they are susceptible to ischemia and venous congestion. Various designs have been suggested to improve the circulatory physiology, and hence survival, of venous flap. More recent designs involve adaptations to the arrangement and number of efferent veins draining arterialized venous flaps. The most commonly used classification system for venous flaps, proposed by Chen, Tang, and Noordhoff, does not afford adequate description of these alternate designs. This article offers a classification system that can incorporate all reported modifications to venous flaps. This simple adaptation to the classification system proposed by Chen et al. restores its usefulness in describing modern variations to venous flap design.

The arterialized saphenous venous flow-through flap with dual venous drainage.

Venous flow‐through flaps are well‐described options for small defects where donor site morbidity is undesirable or in areas where useful local veins are in close proximity to the defect, particularly in the extremities. However, higher rates of flap loss have limited their utility. The saphenous venous flap in particular has been widely sought as a useful flap, and while arterialization of this flap improved survival rates, congestion has remained a limiting feature. We describe report a modification in the design of saphenous venous flaps, whereby an arterialized flap is provided with a separate source of venous drainage, and demonstrate survival of substantially larger venous flaps than previously reported.

Stereolithographic modeling of the deep circumflex iliac artery and its vascular branching: a further advance in computed tomography-guided flap planning.

Stereolithographic Modeling of the Deep Circumflex Iliac Artery and Its Vascular Branching: A Further Advance in Computed Tomography–Guided Flap Planning Sir: P imaging to plan free flaps for microvascular mandibular reconstruction has been shown to improve clinical outcomes and reduce operative times, particularly for the deep circumflex iliac artery flap.1 Imaging with computed tomographic angiography can guide complex bony design and softtissue modifications to the flap. We recently described the use of stereolithographic biomodeling to map bony anatomy to improve operative efficacy; however, the ability to interpret angiographic imaging with these models has been lacking.2 Until now, preoperative computed tomographic angiography scans have been used to predict vascular patterns and trace the vascular pedicle to the bone and soft tissues,3,4 but the interpretation of these scans and direct operative correlation is uniformly difficult. We describe a technique using preoperative imaging with computed tomographic angiography to improve stereolithographic modeling, such that biomodels of both the iliac crest and its vascular supply can be created to a high degree of resolution for operative use. According to our previously described computed tomography–guided biomodeling technique,2 routine computed tomographic angiography is performed and the image data are transferred as raw data for production of image-guided stereolithographic models (BioModels; Anatomics, St. Kilda, Victoria, Australia). These models comprise both bony modeling and angiographic vascular modeling. Using a combination of the differences in contrast levels on imaging, interpretation of the scans, and computer software modeling, the BioModels can effectively differentiate bone from vasculature, and can present the two structures separately within the models (Figs. 1 and 2). Unlike computed tomographic angiography scans alone, these models can be used both preoperatively and intraoperatively to guide operative technique. The use of a single donor-site scan can now achieve accurate mapping for both preoperative and intraoperative analysis of bony anatomy of the donor site, the vascular pedicle, arterial branches from the pedicle to the planned bone flap, and pedicle branches to skin and muscle in composite flaps. This advance in imaging not only supersedes previous modalities, such as plain radiographs (with views superimposed and soft-tissue structures ill-defined) and ultrasound (operator-dependent and low resolution and reproducibility), but also supersedes the previous use of computed tomographic angiography. This technique of combining preoperative computed tomographic angiography with intraoperative vascular biomodeling is potentially able to offer a greater degree of operative guidance and improved accuracy in vascular mapping compared with computed tomographic angiography alone. The finer branches, which can be missed by the interpreting radiologist or surgeon, were clearly demonstrable through computer modeling within the

Free deep circumflex iliac artery vascularised bone flap for reconstruction of the distal radius: Planning with CT angiography

Distal radius fractures in the younger population are often comminuted and intra‐articular, which can increase the complexity of their management. In addition, these patients tend to place high demands on their wrists, and the prevention of functional arthritis necessitates excellent anatomical reduction. Complicated cases such as these are often limited in their management options. We present a complex case of distal radius fracture and bone loss in which initial therapy with nonvascularized bone graft failed, and osteomyelitis was a further complicating factor. With the aid of preoperative planning with computed tomographic angiography (CTA), a deep circumflex iliac artery (DCIA) bone flap was able to be assessed as a reconstructive option. The use of preoperative CTA, the first description of such imaging in this role, was able to delineate the bone to be harvested, confirm its vascular supply, and plan flap harvest. The use of a vascularized bone flap in this setting was thus undertaken and was able to provide an autologous anatomical support for the wrist while reducing the risk of recurrent infection and still preserving internal fixation. This unique application of the free DCIA bone flap was potentiated by CTA, achieving complete healing and good functional outcomes.

Anastomotic failure with a ring anastomotic coupler due to disengagement of its rings

Dear Editor, Microvascular anastomosis is a crucial aspect of free flap reconstruction, as risk for flap failure relies heavily on its success. Intravascular thrombosis at the site of anastomosis is the most commonly encountered complication at this site, and although infrequent, may have disastrous outcomes when it occurs. In terms of the technique for performing a microvascular anastomosis, suturing is the more traditionally performed technique, however, other techniques include fibrin glue, vascular staples, and ring couplers. The use of microvascular anastomotic couplers instead of traditional sutures has been shown to reduce operative time, has comparable or reduced risk for thrombosis and patency and can be performed in areas with limited access. Few clinical studies have addressed potential complications that can occur with this procedure (Institutional Ethical Approval was obtained prospectively, and conforms to the provisions of the Declaration of Helsinki in 1995). Although we have had considerable experience with this device with positive results, we would like to report a complication with the use of these devices that may offer some cautionary steps for future use. During the course of a bilateral breast reconstruction using deep inferior epigastric artery perforator free flaps, anastomosis of each deep inferior epigastric vein to an internal mammary vein was planned with the Unilink ring anastomotic coupler (Microvascular Anastomotic Coupling System, Synovis Micro Companies Alliance, St. Paul, MN), and traditional interrupted suturing was used for arterial anastomosis. All the anastomoses were completed successfully with established flow. During insetting of the flap, it was noted that there was a sudden and rapid increase in bleeding around one flap, and re-exploration of the pedicles was undertaken. It was found that a coupled venous anastomosis had completely disengaged, with separation of each of the eight pins that were engaged around the ring. It was decided that reanastomosis with the same rings would be appropriate, and the same coupler was easily readjoined. Despite this, blood flow across the anastomosis was not achieved. The coupled anastomosis was excised (see Fig. 1), and a new anastomotic coupler was used successfully and without complication. The excised coupler was actually completely patent, and the cause for lack of pedicle flow after reanastomosis with the first coupler was unclear. One possibility was that the multiple attempts at coupled anastomosis might have affected the coupler itself or the vessel. The decision to excise the coupler and the vessel ends being anastomosed aimed to address both of these possibilities. This is a rare complication, and in our experience with more than 1,000 uses of the anastomotic coupler, we have not had a complication from their use. The literature similarly supports a low complication rate with these devices. An avulsion complication has been described by Nishimoto et al., where a tear in the vessel wall occurred after completion of the microvascular anastomosis. However, this avulsion did not occur at the original anastomotic site and coupler rings remained intact. Jandali et al. described the risk of pin disengagement and avulsion of anastomosis postoperatively if coupler rings were not engaged using forcep reinforcement. Other reported complications include vessel wall tearing and *Correspondence to: Warren M Rozen, M.B.B.S., Department of Plastic and Reconstructive Surgery, Dandenong Hospital, Southern Health, Dandenong, Victoria, Australia. E-mail: warrenrozen@hotmail.com