Publications by authors named "Russell J Corlett"

25 Publications

  • Page 1 of 1

Increasing Perfusion Pressure Does Not Distend Perforators or Anastomoses but Reveals Arteriovenous Shuntings.

Plast Reconstr Surg Glob Open 2020 Jun 24;8(6):e2857. Epub 2020 Jun 24.

Taylor Lab, Department of Anatomy and Neurosciences, University of Melbourne, Victoria, Australia.

Background: It has been proposed that hyperperfusion of perforators and distension of anastomotic vessels may be a mechanism by which large perforator flaps are perfused. This study investigates whether increasing perfusion pressure of radiographic contrast in cadaveric studies altered the radiographic appearance of vessels, particularly by distending their anastomotic connections.

Methods: From 10 fresh cadavers, bilateral upper limbs above the elbow were removed. Three cadavers were excluded. Seven pairs of limbs were injected with lead oxide solutions via the brachial artery while distally monitoring intravascular pressure in the radial artery using a pressure transducer. One limb was injected slowly (0.5 mL/s) and the other rapidly (1.5 mL/s) to produce low and high perfusion pressures, respectively. Skin and subcutaneous tissue were then removed and radiographed.

Results: The filling of perforators and their larger caliber branches appeared unchanged between low- and high-pressure injections, with ( = 0.32) and ( = 0.94) ( = 0.10). However, high-pressure injections revealed arteriovenous shunting with filling of the tributaries of the major veins.

Conclusions: This study demonstrated that increased perfusion pressure of the cutaneous arteries (1) did not change the caliber of vessels; (2) did not convert choke to true anastomoses; and (3) revealed arteriovenous shunting between major vessels with retrograde filling of venous tributaries as pressure increased. This suggests that it is not possible to distend anastomotic connections between vascular territories by increasing perfusion alone.
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http://dx.doi.org/10.1097/GOX.0000000000002857DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7339302PMC
June 2020

The Functional Anatomy of the Ophthalmic Angiosome and Its Implications in Blindness as a Complication of Cosmetic Facial Filler Procedures.

Plast Reconstr Surg 2020 10;146(4):745

From the Taylor Lab, Department of Anatomy and Neuroscience, and the Department of Surgery, University of Melbourne; the Plastic and Reconstructive Surgery Unit, The Royal Melbourne Hospital; and the Professorial Plastic Surgery Unit, Epworth Freemasons Hospital.

Background: Blindness following facial filler procedures, although rare, is devastating, usually acute, permanent, and attributed to an ophthalmic artery embolus. However, blindness may be delayed for up to 2 weeks, sometimes following injection at remote sites, suggesting alternative pathways and pathogenesis.

Methods: Seeking solutions, fresh cadaver radiographic lead oxide injection, dissection, and histologic studies of the orbital and facial pathways of the ophthalmic angiosome, performed by the ophthalmic artery and vein, both isolated and together, and facial artery perfusions, were combined with total body archival arterial and venous investigations.

Results: These revealed (1) arteriovenous connections between the ophthalmic artery and vein in the orbit and between vessels in the inner canthus, allowing passage of large globules of lead oxide; (2) the glabella, inner canthi, and nasal dorsum are the most vulnerable injection sites because ophthalmic artery branches are anchored to the orbital rim as they exit, a plexus of large-caliber avalvular veins drain into the orbits, and arteriovenous connections are present; (3) choke anastomoses between posterior and anterior ciliary vessels supplying the choroid and eye muscles may react with spasm to confine territories impacted with ophthalmic artery embolus; (4) true anastomoses exist between ophthalmic and ipsilateral or contralateral facial arteries, without reduction in caliber, permitting unobstructed embolus from remote sites; and (5) ophthalmic and facial veins are avalvular, allowing reverse flow.

Conclusion: The authors' study has shown potential arterial and venous pathways for filler embolus to cause blindness or visual field defects, and is supported clinically by a review of the case literature of blindness following facial filler injection.
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http://dx.doi.org/10.1097/PRS.0000000000007155DOI Listing
October 2020

The quadriceps Femoris allograft as an extension of the Angiosome concept: A cadaveric-based anatomical feasibility study.

Microsurgery 2020 Feb 21;40(2):189-199. Epub 2019 Jun 21.

The Taylor Lab, Department of Anatomy and Neuroscience, University of Melbourne, Parkville, Australia.

Background: Vascularised composite allo-transplantation (VCA) is emerging as a tailored approach for complex tissue reconstruction. This study focuses on the quadriceps VCA as a potential solution for tissue repair, following trauma, necrotising fasciitis/myositis, or tumor ablation.

Methods: Dissections were undertaken in 10 adult cadaveric lower limbs to characterize the blood supply to the quadriceps femoris for en bloc muscle allo-transplantation. A mock cadaveric transplantation was performed to (a) define the best neurovascular VCA design and (b) test the feasibility of the procedure. A review of 54 archival radiograph studies from the institution was also performed to further evaluate the muscle vasculature.

Results: In two lower limbs, the quadriceps VCA was harvested designed on the common and superficial femoral vessels and nerve, which revealed a lengthy and bloody dissection, especially of the veins, which could increase clinically with the inability to use a tourniquet for most of the dissection. However, review of our previous archival studies showed that all four quadriceps muscles are supplied within the lateral circumflex femoral angiosome. In a further eight lower limbs, the quadriceps femoris muscle group consistently received its blood supply from the lateral circumflex femoral angiosome, verified by selective lead oxide injections of this artery. The vastus medialis appeared to have a more tenous blood supply distally based on this angiosome. A successful mock cadaveric transplant was performed based on this data.

Conclusions: We suggest that the best neuromuscular quadriceps VCA should be (a) designed on the lateral circumflex femoral pedicle, (b) should be raised from distal to proximal, and (c) should include the descending genicular vessels as a potential supplemental supply to vastus medialis, should all four muscles be required.
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http://dx.doi.org/10.1002/micr.30479DOI Listing
February 2020

The Role of Anastomotic Vessels in Controlling Tissue Viability and Defining Tissue Necrosis with Special Reference to Complications following Injection of Hyaluronic Acid Fillers.

Plast Reconstr Surg 2018 06;141(6):818e-830e

Parkville, Victoria, Australia.

Background: Most target areas for facial volumization procedures relate to the anatomical location of the facial or ophthalmic artery. Occasionally, inadvertent injection of hyaluronic acid filler into the arterial circulation occurs and, unrecognized, is irreparably associated with disastrous vascular complications. Of note, the site of complications, irrespective of the injection site, is similar, and falls into only five areas of the face, all within the functional angiosome of the facial or ophthalmic artery.

Methods: Retrospective and prospective studies were performed to assess the site and behavior of anastomotic vessels connecting the angiosomes of the face and their possible involvement in the pathogenesis of tissue necrosis. In vivo studies of pig and rabbit, and archival human total body and prospective selective lead oxide injections of the head and neck, were analyzed. Results were compared with documented patterns of necrosis following inadvertent hyaluronic acid intraarterial or intravenous injection.

Results: Studies showed that the location of true and choke anastomoses connecting the facial artery with neighboring angiosomes predicted the tissue at risk of necrosis following inadvertent intraarterial hyaluronic acid injection.

Conclusion: Complications related to hyaluronic acid injections are intimately associated with (1) the anatomical distribution of true and choke anastomoses connecting the facial artery to neighboring ophthalmic and maxillary angiosomes where choke vessels define the boundary of necrosis of an involved artery but true anastomoses allow free passage to a remote site; or possibly (2) retrograde perfusion of hyaluronic acid into avalvular facial veins, especially in the periorbital region, and thereby the ophthalmic vein, cavernous sinus, and brain.
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http://dx.doi.org/10.1097/PRS.0000000000004287DOI Listing
June 2018

The Functional Angiosome: Clinical Implications of the Anatomical Concept.

Plast Reconstr Surg 2017 Oct;140(4):721-733

Parkville, Victoria, Australia.

Background: The angiosome is a three-dimensional block of tissue supplied by a source vessel with its boundary outlined either by an anastomotic perimeter of reduced-caliber choke vessels or by true anastomoses with no reduction of vessel caliber. This article focuses on the role of these anastomotic vessels in defining flap survival or the necrotic pattern seen in fulminating meningococcal septicemia.

Methods: Experiments in pigs, dogs, guinea pigs, and rabbits over the past 46 years were reviewed, focusing on the necrosis line of flaps, the effects of various toxins in vivo, and correlating these results in the clinical setting.

Results: Experimentally, choke anastomoses are functional and control flow between perforator angiosomes. They (1) permit capture of an adjacent angiosome when the flap is raised on a cutaneous perforator in 100 percent of cases, with the necrosis line occurring usually in the next interperforator connection; (2) confine flow to the territory of the involved artery when a toxin is introduced by spasm around its perimeter; and (3) lose this property of spasm when choke vessels are converted to true anastomoses following surgical delay, or where true anastomoses occur naturally, thereby allowing unimpeded blood flow and capture of additional angiosome territories. Clinical experience supports these observations.

Conclusions: The functional angiosome is the volume of tissue that clinically can be isolated on a source vessel. The area extends beyond its anatomical territory to capture an adjacent territory if connections are by choke anastomoses, or more if they are by true anastomoses.
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http://dx.doi.org/10.1097/PRS.0000000000003694DOI Listing
October 2017

Angiosome-Based Allografts: Vascularized Composite Allotransplantation for Tailored Subunit Reconstruction with Volkmann Ischemic Contracture as a Case in Point.

Plast Reconstr Surg 2017 Jun;139(6):1291e-1304e

Melbourne, Victoria, Australia.

Background: As we enter an age with new approaches to tissue reconstruction, the emphasis on the adage "like for like" has become even more relevant. This study illustrates the potential for several tailored vascularized composite allotransplantation reconstructive techniques and, in particular, for the management of Volkmann contracture.

Methods: Twenty fresh cadaver dissections and 30 archival lead oxide radiographic studies were examined to (1) identify potential upper limb vascularized composite allotransplantation donor sites (i.e., elbow, forearm, and flexor tendon complex) and (2) demonstrate a "mock transplant" of the vascularized volar forearm allograft for a severe Volkmann ischemia defect. They were designed without skin to reduce antigenicity.

Results: The elbow joint was supplied within the brachial angiosome and the flexor tendon complex of the flexor digitorum superficialis and flexor digitorum profundus by the superficial palmar arch of the ulnar angiosome. The forearm allograft of flexor muscles, median, ulnar, and anterior interosseous nerves, when harvested on the brachial vessels, was supplied within the radial, ulnar, and anterior interosseous angiosomes but could be based on the ulnar artery alone because of intramuscular connections with the other territories. A mock transplant was performed with a distal-to-proximal dissection of the allograft, facilitating the best and fastest technique.

Conclusions: This application of the angiosome concept highlights the anatomical feasibility of the volar forearm vascularized composite allotransplantation donor site focusing on a complex subunit problem in the upper limb-severe Volkmann ischemic contracture. It demonstrates the potential use and immunologic advantage of subdivided and modified nonskin variations of vascularized composite allotransplantation in reconstructive transplantation surgery.

Clinical Question/level Of Evidence: Therapeutic, V.
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http://dx.doi.org/10.1097/PRS.0000000000003360DOI Listing
June 2017

The Relationship of Superficial Cutaneous Nerves and Interperforator Connections in the Leg: A Cadaveric Anatomical Study.

Plast Reconstr Surg 2017 Apr;139(4):994e-1002e

Melbourne, Victoria, Australia.

Background: The lower limb is a source of many flaps both for closure of local defects and for free transfer. Fasciocutaneous flap techniques have been progressively refined, although the vascular basis for their success needs clarification.

Methods: Archival studies of 48 lower limbs were reviewed and combined with 20 studies of lower limbs from fresh cadavers, making a total of 68 investigations. Lower limbs were injected with a dilute lead oxide solution; the integument was removed and radiographed; and the cutaneous nerves were dissected, tagged with wire, radiographed again, and their paths traced on the original images.

Results: The major cutaneous nerves in the leg are paralleled by a longitudinal vascular axis often comprising long branches with large-caliber true anastomotic connections between perforators. The most highly developed vascular axes followed the medial sural cutaneous and saphenous nerves, together with their accompanying veins, immediately superficial to the deep fascia. The intervening areas were characterized by shorter branches usually connected by small-caliber choke anastomotic connections.

Conclusions: These findings provide the anatomical basis for the observed reliability of longitudinal flaps in the leg. The superficial cutaneous nerves of the leg, especially the saphenous and medial sural cutaneous nerves, are paralleled by a vascular axis on or beside the nerve comprising long perforator branches connected usually but not always by large-caliber true anastomotic connections. This emphasizes the importance of understanding the characteristics of interperforator anastomoses when designing and raising flaps.
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http://dx.doi.org/10.1097/PRS.0000000000003157DOI Listing
April 2017

The Lymphatic Anatomy of the Lower Eyelid and Conjunctiva and Correlation with Postoperative Chemosis and Edema.

Plast Reconstr Surg 2017 Mar;139(3):628e-637e

Melbourne, Toorak, and Fitzroy, Victoria, Australia.

Background: There are minimal data in the literature regarding the lymphatic drainage of the conjunctiva and lower eyelid and the relationship with postoperative chemosis and edema.

Methods: Injection, microdissection, and histologic and radiologic studies were conducted on 12 hemifacial fresh cadaver specimens. Indocyanine green lymphography was conducted in five volunteers.

Results: Histology identified lymphatic vessels superficial and deep to the orbicularis oculi. Cadaveric dissection, injection, and radiographic studies identified interconnecting superficial and deep facial lymphatic systems and a conjunctival lymphatic network draining through the tarsal plate to the deep lymphatic system. The superficial lymphatic collectors traveled in subcutaneous fat within the lateral orbital and nasolabial fat compartments. The lateral deep lymphatic collectors traveled beneath orbicularis oculi, then through the superficial orbicularis retaining ligament, and into the sub-orbicularis oculi fat in the roof of the prezygomatic space. These vessels descended to preperiosteal fat at the level of zygomaticocutaneous ligaments to travel adjacent to the facial nerve into preauricular nodes. Indocyanine green lymphography identified correlating draining pathways laterally to the parotid nodes and medially to submandibular nodes.

Conclusions: The authors have found that the lower eyelid and conjunctiva are drained by interconnecting superficial and deep lymphatic systems of the face. The superficial system is vulnerable to damage in incisions and dissection in the infraorbital area. The deep system is vulnerable to damage in dissection around the orbicularis retaining ligament and the zygomaticocutaneous ligaments. The authors suggest that concurrent damage to both the superficial and deep lymphatic systems, especially laterally, may be responsible for postoperative chemosis and edema.
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http://dx.doi.org/10.1097/PRS.0000000000003094DOI Listing
March 2017

The Evolution of Free Vascularized Bone Transfer: A 40-Year Experience.

Plast Reconstr Surg 2016 Apr;137(4):1292-1305

Melbourne, Victoria, Australia.

Background: The first successful free vascularized bone flap was performed on June 1, 1974 (and reported in 1975), using the fibula. This was followed by the iliac crest based on the superficial circumflex iliac artery in 1975 and then the deep circumflex iliac artery in 1978.

Methods: A total of 384 transfers using fibula (n = 198), iliac crest (n = 180), radius (n = 4), rib (n = 1), and metatarsal (n = 1) were used between June of 1974 and June of 2014 for reconstruction of the mandible (n = 267), maxilla (n = 20), clavicle (n = 1), humerus (n = 8), radius and ulna (n = 21), carpus (n = 3), pelvis (n = 2), femur (n = 11), tibia (n = 47), and foot bones (n = 4). Indications were tumor ablation (n = 286), trauma (n = 84), osteomyelitis (n = 2), and the congenital deformities hemifacial microsomia (n = 2) and pseudarthrosis of the tibia (n = 9) and ulna (n = 1).

Results: Successful transfer was achieved in 95 percent of patients. Union varied with the recipient bone, from 6 to 8 weeks in the jaw, 2 to 3 months in the upper limb, and 3 to 4 months in the femur and tibia. Union was fastest with iliac crest. The fibula provided easier dissection; it could be raised on either peroneal or anterior tibial vessels; the skin flap could be designed distally; it could be placed centrally in the medullary cavity of long bones; and hairline stress fracture in the lower limb frequently preceded rapid subperiosteal hypertrophy. The fibula lacks sufficient height for osseointegration, whereas iliac crest is ideal. Osteotomies of either bone are possible to straighten or increase curvature.

Conclusions: The fibula is best for long bone or angle-to-angle jaw reconstruction, especially in edentulous patients. Iliac crest is best for hemimandible, curved bones (pelvis, carpus, and metacarpus), and as an alternative for short, straight, 6- to 8-cm-long bone defects.
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http://dx.doi.org/10.1097/PRS.0000000000002040DOI Listing
April 2016

Reply: understanding the fascial supporting network of the breast: key ligamentous structures in breast augmentation and a proposed system of nomenclature.

Plast Reconstr Surg 2014 Aug;134(2):326e-328e

Taylor Laboratory, Department of Anatomy and Neuroscience, University of Melbourne, Royal Melbourne Hospital, Melbourne, Australia.

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http://dx.doi.org/10.1097/PRS.0000000000000542DOI Listing
August 2014

Understanding the fascial supporting network of the breast: key ligamentous structures in breast augmentation and a proposed system of nomenclature.

Plast Reconstr Surg 2014 Feb;133(2):273-281

Potts Point, New South Wales, Australia From Taylor Laboratory, Department of Anatomy and Neuroscience, University of Melbourne, Royal Melbourne Hospital.

Background: The fascial system of the breast has, to date, only been described in general terms. This anatomical study has developed two distinct methods for better defining existing breast structures such as the inframammary fold, as well as defining previously unnamed ligamentous structures.

Methods: The authors harvested and examined 40 frozen, entire chest wall cadavers. Initially, 15 embalmed cadavers were studied with a combination of blunt and sharp dissection, which proved to be inaccurate. A further 20 fresh and five embalmed chest walls were harvested, frozen, and then sectioned with a bandsaw (3-cm slices) and knife (1.5- to 4-cm slices) depending on the area studied. Sagittal, horizontal, and oblique sections along the length of the ribs were created and then dissolved using either sodium hydroxide or alcohol dehydration followed by xylene immersion. Constant fascial connections between the breast parenchyma, superficial fascia, pectoralis muscle (deep) fascia, and bone were observed.

Results: Specimens clearly demonstrated internal structures responsible for the surface landmarks of the breast. The precise configuration of the infra mammary fold was clearly visible, and new ligamentous structures were identified and named.

Conclusions: Knowing the location and interrelationship of these structures is particularly important in breast augmentation. Reappraisal of the anatomy in this area has enabled precise identification of ligamentous structures in the breast. Correlation of the findings in this article to specific clinical conditions or modes of treatment can be proven only by a clinical series that scientifically addresses the necessity and efficacy of preserving, releasing, or repositioning any of these structures.
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http://dx.doi.org/10.1097/01.prs.0000436798.20047.dcDOI Listing
February 2014

Reconstruction of the nasolabial fold using a fascia lata sheet graft: a modified technique.

Plast Reconstr Surg 2013 Nov;132(5):1276-1279

Melbourne, Victoria, Australia From the Taylor Lab, Department of Anatomy and Neuroscience, University of Melbourne, Royal Melbourne Hospital.

Unlabelled: A refinement over existing static facial sling techniques to reconstruct the nasolabial fold in longstanding facial palsy is presented. The innovative use of fascia lata sheet graft instead of strips facilitates greater intraoperative control over the contour of the reconstructed fold and provides a wide area of attachments of the graft. This technique has a reduced incidence of complications and can be adjusted with minimal scarring as a secondary procedure if necessary.

Clinical Question/level Of Evidence: Therapeutic, V.
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http://dx.doi.org/10.1097/PRS.0b013e3182a4c22bDOI Listing
November 2013

The gracilis myocutaneous free flap: a quantitative analysis of the fasciocutaneous blood supply and implications for autologous breast reconstruction.

PLoS One 2012 9;7(5):e36367. Epub 2012 May 9.

The Taylor Lab, Department of Anatomy and Neurosciences, University of Melbourne, Parkville, Victoria, Australia.

Background: Mastectomies are one of the most common surgical procedures in women of the developed world. The gracilis myocutaneous flap is favoured by many reconstructive surgeons due to the donor site profile and speed of dissection. The distal component of the longitudinal skin paddle of the gracilis myocutaneous flap is unreliable. This study quantifies the fasciocutaneous vascular territories of the gracilis flap and offers the potential to reconstruct breasts of all sizes.

Methods: Twenty-seven human cadaver dissections were performed and injected using lead oxide into the gracilis vascular pedicles, followed by radiographic studies to identify the muscular and fasciocutaneous perforator patterns. The vascular territories and choke zones were characterized quantitatively using the 'Lymphatic Vessel Analysis Protocol' (LVAP) plug-in for Image J® software.

Results: We found a step-wise decrease in the average vessel density from the upper to middle and lower thirds of both the gracilis muscle and the overlying skin paddle with a significantly higher average vessel density in the skin compared to the muscle. The average vessel width was greater in the muscle. Distal to the main pedicle, there were either one (7/27 cases), two (14/27 cases) or three (6/27 cases) minor pedicles. The gracilis angiosome was T-shaped and the maximum cutaneous vascular territory for the main and first minor pedicle was 35 × 19 cm and 34 × 10 cm, respectively.

Conclusion: Our findings support the concept that small volume breast reconstructions can be performed on suitable patients, based on septocutaneous perforators from the minor pedicle without the need to harvest any muscle, further reducing donor site morbidity. For large reconstructions, if a 'T' or tri-lobed flap with an extended vertical component is needed, it is important to establish if three territories are present. Flap reliability and size may be optimized following computed tomographic angiography and surgical delay.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0036367PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3348940PMC
September 2012

The anatomical (angiosome) and clinical territories of cutaneous perforating arteries: development of the concept and designing safe flaps.

Plast Reconstr Surg 2011 Apr;127(4):1447-1459

Parkville, Victoria, Australia From the Jack Brockhoff Reconstructive Plastic Surgery Research Unit, Department of Anatomy and Cell Biology, University of Melbourne.

Background: Island "perforator flaps" have become state of the art for free-skin flap transfer. Recent articles by Saint-Cyr et al. and Rozen et al. have focused on the anatomical and the clinical territories of individual cutaneous perforating arteries in flap planning, and it is timely to compare this work with our angiosome concept.

Methods: The angiosome concept, published in 1987, was reviewed and correlated with key experimental and clinical work by the authors, published subsequently at different times in different journals. In addition, new data are introduced to define these anatomical and clinical territories of the cutaneous perforators and to aid in the planning of safe skin flaps for local and free-flap transfer.

Results: The anatomical territory of a cutaneous perforator was defined in the pig, dog, guinea pig, and rabbit by a line drawn through its perimeter of anastomotic vessels that link it with adjacent perforators in all directions. The safe clinical territory of that perforator, seen not only in the same range of animals but also in the human using either the Doppler probe or computed tomography angiography to locate the vessels, was found reliably to extend to include the anatomical territory of the next adjacent cutaneous perforator, situated radially in any direction.

Conclusion: The data provided by Saint-Cyr et al. and Rozen et al., coupled with the authors' own original work on the vascular territories of the body and their subsequent studies, reinforce the angiosome concept and provide the basis for the design of safe flaps for patient benefit.
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http://dx.doi.org/10.1097/PRS.0b013e318208d21bDOI Listing
April 2011

The effect of anterior abdominal wall scars on the vascular anatomy of the abdominal wall: A cadaveric and clinical study with clinical implications.

Clin Anat 2009 Oct;22(7):815-22

Department of Anatomy and Cell Biology, Jack Brockhoff Reconstructive Plastic Surgery Research Unit, The University of Melbourne, Parkville, Victoria, Australia.

The anterior abdominal wall integument is frequently used in a range of reconstructive flaps. These tissues are supplied by the deep and superficial inferior epigastric arteries (DIEA and SIEAs) and the deep and superficial superior epigastric arteries (DSEA and SSEAs). Previous abdominal wall surgery alters this vascular anatomy and may influence flap design. One hundred and sixty-eight patients underwent abdominal wall computed tomographic angiography (CTA) for preoperative imaging. Fifty-eight of these patients had undergone previous abdominal surgery, and were assessed for scar pattern and relationship to the course and distribution of all major axial vessels and perforators. Two cadaveric abdominal wall specimens with midline abdominal scars underwent contrast injection of the DIEAs and DSEAs, with subsequent CTA. The course and distribution of all cutaneous vessels were assessed. In all clinical and cadaveric cases, the vasculature of the abdominal wall had been altered by previous surgery. In the clinical cases, vascular architecture was universally altered in the region of the scar, often modifying the filling patterns of the abdominal wall and occasionally precluding the use of an abdominal wall flap. In both cadaveric specimens, regions of non-filling were evident upon contrast injection, highlighting the angiosomes not supplied by the DIEA or DSEA. Previous abdominal wall surgery necessarily alters the vascular architecture of the abdominal wall, and may alter the source vessels supplying cutaneous tissues. CTA was useful in identifying and delineating these changes, and may be used as a preoperative tool in this role.
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http://dx.doi.org/10.1002/ca.20851DOI Listing
October 2009

The perforator angiosome: a new concept in the design of deep inferior epigastric artery perforator flaps for breast reconstruction.

Microsurgery 2010 ;30(1):1-7

Department of Anatomy and Cell Biology, The University of Melbourne, Jack Brockhoff Reconstructive Plastic Surgery Research Unit, Parkville, Victoria, 3050, Australia.

Background: The previously described "perfusion zones" of the abdominal wall vasculature are based on filling of the deep inferior epigastric artery (DIEA) and all its branches simultaneously. With the advent of the DIEA perforator flap, only a single or several perforators are included in supply to the flap. As such, a new model for abdominal wall perfusion has become necessary. The concept of a "perforator angiosome" is thus explored.

Methods: A clinical and cadaveric study of 155 abdominal walls was undertaken. This comprised the use of 10 whole, unembalmed cadaveric abdominal walls for angiographic studies, and 145 abdominal wall computed tomographic angiograms (CTAs) in patients undergoing preoperative imaging of the abdominal wall vasculature. The evaluation of the subcutaneous branching pattern and zone of perfusion of individual DIEA perforators was explored, particularly exploring differences between medial and lateral row perforators.

Results: Fundamental differences exist between medial row and lateral row perforators, with medial row perforators larger (1.3 mm vs. 1 mm) and more likely to ramify in the subcutaneous fat toward the contralateral hemiabdomen (98% of cases vs. 2% of cases). A model for the perfusion of the abdominal wall based on a single perforator is presented.

Conclusion: The "perforator angiosome" is dependent on perforator location, and can mapped individually with the use of preoperative imaging.
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http://dx.doi.org/10.1002/micr.20684DOI Listing
May 2010

The pudendal thigh flap for vaginal reconstruction: optimising flap survival.

J Plast Reconstr Aesthet Surg 2010 May 26;63(5):826-31. Epub 2009 Apr 26.

Jack Brockhoff Reconstructive Plastic Surgery Research Unit, Room E533, Department of Anatomy and Cell Biology, University of Melbourne, Grattan Street, Parkville, 3050 Victoria, Australia.

Background: The pudendal thigh fasciocutaneous (PTF) flap is a useful flap in perineal reconstruction, that is reliable when small but is traditionally unreliable when large flaps are raised. Large flaps in particular, are associated with an increased incidence of apical necrosis. Thorough descriptions of the vascular anatomy of this flap have been lacking from the literature, with the current study evaluating this anatomy, aiming to provide the anatomical basis for vascular problems and for techniques to maximise its survival.

Methods: Five unembalmed human cadaveric pelvis specimens were studied. Lead oxide injectant enabled radiographic and dissection analysis of the arterial anatomy of the integument of the perineum.

Results: A consistent pattern of vascular supply was found in all specimens. 1: the blood supply to the pelvic floor was supplied sequentially by the posterior labial/scrotal arteries, cutaneous branches from the anterior branch of the obturator artery, and branches from the external pudendal arteries. 2: these vessels ran close to the midline, medial to the PTF flap. 3: the posterior labial/scrotal arteries were deep to the Colles' fascia and the branches from the obturator artery and external pudendal arteries were located superficial to the Colles' fascia.

Conclusion: This study has demonstrated that the PTF flap is a three vascular territory flap and that the pedicle is situated close to the midline. This may explain why regions of the PTF flap may have a potentially precarious blood supply, and suggests that the PTF flap should be designed more medially. Given the third territory of supply to the apex of the flap, a delay procedure may help to avoid flap necrosis.
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http://dx.doi.org/10.1016/j.bjps.2009.02.060DOI Listing
May 2010

The lumbar artery perforators: a cadaveric and clinical anatomical study.

Plast Reconstr Surg 2009 Apr;123(4):1229-1238

Parkville, Victoria, Australia From the Jack Brockhoff Reconstructive Plastic Surgery Research Unit, Department of Anatomy and Cell Biology, University of Melbourne.

Background: The lumbar region has been scarcely explored as a donor site for free tissue transfer or as a free flap recipient site. The lumbar integument provides a versatile prospective flap site, with a potentially well-concealed scar. Similarly, defects of this region can require recipient vessels that may be difficult to identify. Although lumbar artery perforators have been described, the reliability of perforators in this region remains questionable.

Methods: An anatomical study was undertaken combining both cadaveric and in vivo analysis of the lumbar vessels. The cadaveric component comprised both dissection and angiographic studies in fresh and embalmed cadavers (36 lumbar regions in 18 cadavers), and the clinical study comprised a computed tomographic angiographic study (44 sides in 22 patients) and an operative case report.

Results: Perforators were shown to arise from all eight lumbar arteries to enter the lumbar integument, with their size, location, and course described. Lower lumbar perforators were more often septocutaneous and of larger caliber. A case in which the fourth lumbar artery and concomitant vein were used as free flap recipient vessels is described, the first such reported case in the literature.

Conclusions: Improving the incidence of identifying lumbar perforators of large caliber and with a septocutaneous course can be achieved by selecting lower lumbar vessels, or with the use of preoperative computed tomographic angiography. Computed tomographic angiography can successfully identify the location, size, and course of lumbar artery perforators and can aid flap design. Lumbar artery perforators are highly useful for both donor and recipient vessels in free flap surgery.
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http://dx.doi.org/10.1097/PRS.0b013e31819f299eDOI Listing
April 2009

Perforator dilatation induced by body weight gain is not reversed by subsequent weight loss: implications for perforator flaps.

Plast Reconstr Surg 2008 Dec;122(6):1765-1772

Parkville, Victoria, Australia From the Jack Brockhoff Reconstructive Plastic Surgery Research Unit, Department of Anatomy and Cell Biology, the Department of Surgery, Royal Melbourne Hospital and University of Melbourne, and the Ludwig Institute for Cancer Research, Royal Melbourne Hospital.

Background: Perforator flaps frequently rely on small vessels for their supply, which may lead to problems with flap viability. To ensure a more dependable blood supply, larger perforators are sought either on preoperative imaging or intraoperatively. Body weight gain is usually associated with increasing cutaneous perforator size. The question remains whether body weight loss causes a diminution in the size of these perforators.

Methods: Sixty-seven consecutive patients were recruited, each undergoing either deep inferior epigastric perforator flap breast reconstruction (n = 57) or abdominoplasty (n = 10), with measurement of all abdominal wall deep inferior epigastric artery perforators. This was calculated with either preoperative computed tomographic angiography scans or intraoperative measurements.

Results: Higher body mass index (>29) was associated with a 2.7-fold increase in number of 1.5-mm perforators (p < 0.01), a 1.3-fold increase in the average diameter of the five largest perforators (p < 0.01), and a 1.2-fold increase in the diameter of the largest perforator (p < 0.01). Subsequent loss of body weight did not reduce the size of perforators. Patients who had been previously heavier had an average of a 2.6- to 3.3-fold increase in the number of perforators larger than 1.5 mm (p < 0.01) and a 1.2-fold increase in the average diameter of the five largest perforators.

Conclusions: Body weight gain results in irreversible dilatation of the cutaneous perforators of the abdominal wall, with subsequent body weight loss not decreasing the size of perforators, facilitating optimal flap harvest in perforator flap surgery. Patients can therefore be advised to lose weight preoperatively, with benefit to both flap harvest and operative outcomes.
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http://dx.doi.org/10.1097/PRS.0b013e31818cc0ffDOI Listing
December 2008

Magnetic resonance angiography in the preoperative planning of DIEA perforator flaps.

Plast Reconstr Surg 2008 Dec;122(6):222e-223e

Jack Brockhoff Reconstructive Plastic Surgery Research Unit, University of Melbourne (Rozen) Department of Radiology, Royal Melbourne Hospital (Stella, Phillips) Jack Brockhoff Reconstructive Plastic Surgery Research Unit, University of Melbourne, Parkville, Victoria, Australia (Ashton, Corlett, Taylor).

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http://dx.doi.org/10.1097/PRS.0b013e31818d2246DOI Listing
December 2008

Lymphatic drainage of the nasal fossae and nasopharynx: preliminary anatomical and radiological study with clinical implications.

Head Neck 2009 Jan;31(1):52-7

Jack Brockhoff Reconstructive Plastic Surgery Research Unit, Royal Melbourne Hospital, Department of Anatomy and Cell Biology, University of Melbourne, Victoria, Australia.

Background: The lymphatic pathways of the nasal cavity are of enormous clinical importance. To date there has been no accurate radiographic record of these pathways.

Methods: Four halves of the head and neck from 2 fresh human cadavers were studied.

Results: The capillary network arises from the mucous membrane of the atrium, the turbinates, the floor of the nasal cavity, and the nasopharynx. They drain into the lateral pharyngeal and retropharyngeal lymph nodes. There is 1 lymphatic communication at the junction of the lateral posterior wall of the turbinates and the nasopharynx and another communication between 2 groups of lymph nodes situated between the origin of the facial artery and the bifurcation of the carotid artery.

Conclusions: A rich avalvular lymph capillary network exists in the mucous membrane and 2 major lymph collecting vessels course through the parapharyngeal space to multiple first tier lymph nodes.
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http://dx.doi.org/10.1002/hed.20926DOI Listing
January 2009

Avoiding denervation of rectus abdominis in DIEP flap harvest II: an intraoperative assessment of the nerves to rectus.

Plast Reconstr Surg 2008 Nov;122(5):1321-1325

Parkville, Victoria, Australia From the Jack Brockhoff Reconstructive Plastic Surgery Research Unit, Department of Anatomy and Cell Biology, University of Melbourne.

Background: The deep inferior epigastric artery perforator (DIEP) flap aims to reduce donor-site morbidity by minimizing rectus muscle damage; however, damage to motor nerves during perforator dissection may denervate rectus muscle. Although cadaveric research has demonstrated that individual nerves do not arise from single spinal cord segments and are not distributed segmentally, the functional distribution of individual nerves remains unknown. Using intraoperative nerve stimulation, the current study describes the motor distribution of individual nerves supplying the rectus abdominis, providing a guide to nerve dissection during DIEP flap harvest.

Methods: Twenty rectus abdominis muscles in 17 patients undergoing reconstructive surgery involving rectus abdominis (DIEP, transverse rectus abdominis musculocutaneous, or vertical rectus abdominis musculocutaneous flaps) underwent intraoperative stimulation of nerves innervating the infraumbilical segment of the rectus. Nerve course and extent of rectus muscle contraction were recorded.

Results: In each case, three to seven nerves entered the infraumbilical segment of the rectus abdominis. Small nerves (type 1) innervated small longitudinal strips of rectus muscle, rather than transverse strips as previously described. There was significant overlap between adjacent type 1 nerves. In 18 of 20 cases, a single large nerve (type 2) at the level of the arcuate line supplied the entire width and length of rectus muscle.

Conclusions: Nerves innervating the rectus abdominis are at risk during DIEP flap harvest. Small, type 1 nerves have overlapping innervation from adjacent nerves and may be sacrificed without functional detriment. However, large type 2 nerves at the level of the arcuate line innervate the entire width of rectus muscle without adjacent overlap and may contribute to donor-site morbidity if sacrificed.
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http://dx.doi.org/10.1097/PRS.0b013e3181881e18DOI Listing
November 2008

Anatomical variations in the harvest of anterolateral thigh flap perforators: a cadaveric and clinical study.

Microsurgery 2009 ;29(1):16-23

Jack Brockhoff Reconstructive Plastic Surgery Research Unit, Department of Anatomy and Cell Biology, The University of Melbourne, Victoria, Australia.

Background: The anterolateral thigh (ALT) flap has become increasingly popular due to its versatility and minimal donor site morbidity. Its major limitation has been uncertainty in predicting perforator anatomy, with the occasional absence of suitable perforators and high variability in their size and course. The variability of this anatomy has not been adequately explored previously.

Methods: A cadaveric study was undertaken, in which 19 thighs (from 10 fresh cadavers) underwent contrast injection and angiographic imaging. Anatomical variations of the vasculature were recorded. A clinical study of 44 patients undergoing ALT flap reconstruction was also undertaken. Perforator anatomy was described in the first 32 patients, and the subsequent 12 patients underwent computed tomography angiography with a view to predicting individual anatomy and improving operative outcome.

Results: Cadaver angiography was able to highlight and classify the variations in arterial anatomy, with four patterns observed and marked variability between cases. In 32 patients undergoing ALT flaps without preoperative CT angiography (CTA), five patients (16%) did not have any suitable perforators from the descending branch of the lateral circumflex femoral artery. By selecting the limb of choice with preoperative CTA, the incidence of flap unsuitability was reduced to 0%. Comparing CTA with Doppler, CTA was more accurate (sensitivity 100%) and provided more information.

Conclusion: The perforators supplying the ALT flap show significant variability in location and course, with the potential for unsuitable perforators limiting flap success. Preoperative CTA can demonstrate the vascular anatomy and can aid perforator selection and operative success.
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http://dx.doi.org/10.1002/micr.20550DOI Listing
April 2009

A comparative anatomical study of brachioradialis and flexor carpi ulnaris muscles: implications for total tongue reconstruction.

Plast Reconstr Surg 2008 Mar;121(3):816-829

Melbourne, Victoria, Australia From the Jack Brockhoff Reconstructive Plastic Surgery Research Unit, Royal Melbourne Hospital, Department of Anatomy and Cell Biology, University of Melbourne.

Background: Total or subtotal glossectomy following resection of intraoral tumors causes significant morbidity. Recent surgical endeavors have focused on the creation of a neotongue with both sensory and motor innervation. Although various local or regional free flaps have been used for this purpose, the optimal donor site remains undecided. The authors compared the neurovascular anatomy of the brachioradialis and flexor carpi ulnaris to assess their suitability as donor muscles together with overlying skin for functional total or subtotal tongue reconstruction.

Methods: Eighty-eight brachioradialis and 80 flexor carpi ulnaris muscles were studied, comprising 120 dissected specimens, 18 arterial studies, two venous studies, 20 histologic studies, and eight neurovascular studies.

Results: The dominant vascular pattern of the brachioradialis varied. The major pedicle arose from the radial (38 percent), radial recurrent (42 percent), and brachial arteries (20 percent). The muscle also lacked a single neurovascular pedicle. The vasculature of the flexor carpi ulnaris was consistent. The ulnar artery supplied the dominant pedicle in 86 percent of cases. The entry point of motor innervation is near that of the vascular pedicles. A minor distal nerve accompanied the main vascular pedicle in 65 percent of cases. The overlying skin was supplied by musculocutaneous perforators. The lower lateral cutaneous nerve of the arm supplied the skin over the brachioradialis, and the medial cutaneous nerves of the arm and forearm provided sensation over the flexor carpi ulnaris.

Conclusion: The authors delineated the anatomical advantages of the flexor carpi ulnaris over the brachioradialis for total or subtotal tongue reconstruction.
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http://dx.doi.org/10.1097/01.prs.0000299920.14548.2aDOI Listing
March 2008

The DIEA branching pattern and its relationship to perforators: the importance of preoperative computed tomographic angiography for DIEA perforator flaps.

Plast Reconstr Surg 2008 Feb;121(2):367-373

Parkville, Victoria, Australia From the Jack Brockhoff Plastic and Reconstructive Surgery Research Unit, University of Melbourne.

Background: Abdominal donor-site flaps based on the deep inferior epigastric artery (DIEA) are the most common flaps used in autologous breast reconstruction. With significant variation in the vascular anatomy of the DIEA, preoperative imaging is desirable. Computed tomographic angiography, recently described for this purpose, uniquely demonstrates the branching pattern of the DIEA. The authors sought to correlate the DIEA branching pattern to the location and course of perforators as a preoperative planning tool for perforator flaps.

Methods: Forty-five cadaveric hemi-abdominal walls were used for contrast injection of the DIEA with subsequent radiographic imaging. The branching pattern on radiography was thus correlated to the location and intramuscular course of perforators, from the main DIEA trunk to the point of the penetrating rectus sheath.

Results: The DIEA branching pattern correlated closely with the course of perforators. A bifurcating (type II) branching pattern demonstrated a reduced transverse distance traversed by each perforator, whereas a trifurcating (type III) branching pattern demonstrated significantly greater transverse distances (p = 0.0002). Type I vessels were intermediate. Vessel branching type, however, displayed no significant correlation with the number of perforators (p = 0.56).

Conclusions: The distances traversed by perforators were significantly reduced with a bifurcating branching pattern of the DIEA, particularly those originating from the lateral branch, and were greatest with a trifurcating branching pattern. Increased transverse distances correlate with greater rectus muscle sacrificed during perforator flap surgery. As computed tomographic angiography is the optimal modality for demonstrating this pattern preoperatively, the authors suggest its use for preoperative assessment in transverse rectus abdominis musculocutaneous and DIEA perforator flaps.
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http://dx.doi.org/10.1097/01.prs.0000298313.28983.f4DOI Listing
February 2008
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