Gary Arbique

Arterial and venous anatomies of the deep inferior epigastric perforator and superficial inferior epigastric artery flaps.

Background: This study uses three- and four-dimensional computed tomographic angiography and venography to evaluate the microvascular anatomy and perfusion of the deep inferior epigastric artery perforator (DIEP) and superficial inferior epigastric artery (SIEA) flaps. Methods: Ten DIEP flaps harvested from fresh cadavers and two abdominoplasty specimens were used. Studies of the largest single perforators from the medial and lateral rows were performed. Injections of the vena comitans of the perforators and of the superficial inferior epigastric veins were performed to evaluate venous drainage. Results: Zone IV was not perfused following injection of a lateral row perforator, whereas injection of a medial row perforator consistently resulted in perfusion of zone IV. Image analysis revealed the presence of large-diameter linking vessels at the level of the subdermal plexus between the perforators of the medial row, whereas lateral row perforators predominantly perfused the lateral aspect of the flap and perfused the medial row perforators by means of recurrent flow through the subdermal plexus. Medial row perforators perfused the flap in a central elliptical pattern, whereas lateral row perforators predominantly perfused the ipsilateral portion of the flap. The SIEA vessel branches were seen to course to the subdermal plexus and then to perfuse ipsilateral perforators through the subdermal plexus. Venous drainage occurred by means of the superficial inferior epigastric veins and the venae comitantes of the perforators. Conclusions: This study demonstrates that flow through medial and lateral row perforators occurs in physiologically stereotyped patterns. A medial row perforator should be selected if zone IV perfusion is required. The SIEA was consistently seen to only perfuse a hemiflap.

The anatomy of suborbicularis fat: Implications for periorbital rejuvenation

Background: Periorbital rejuvenation has increasingly relied on augmentation with fillers. Numerous techniques have been described, including augmentation of the sub–orbicularis oculi fat. Cadaver studies initiated 2 years ago yielded presumptive evidence that sub–orbicularis oculi fat consists of two distinct regions. Knowledge of this anatomy is important for precision in facial rejuvenation. Methods: A pilot study was performed with radiopaque dye injection into the sub–orbicularis oculi fat and computed tomographic evaluation with three-dimensional reconstruction. Eight hemifacial fresh cadaver dissections were then performed with a modified dye injection technique to isolate regions of sub–orbicularis oculi fat and periorbital fat. The relationship of suborbicularis fat to deep cheek fat was observed. Results: This study confirms the presence of two distinct regions of sub–orbicularis oculi fat. A medial component extends along the orbital rim from the medial limbus to the lateral canthus. A lateral component extends from the lateral canthus to the temporal fat pad. The lateral component terminated superiorly at the lateral orbital thickening. Deep cheek fat abutted the medial sub–orbicularis oculi fat, thus creating a deep fat system in continuity across the face of the maxilla and along the orbital rim. Conclusions: This anatomy helps to define midface adipose tissue as a system of superficial and deep fat, of which medial and lateral sub–orbicularis oculi fat are a part. A working hypothesis of facial aging continues with the concept that loss and/or ptosis of deep fat compartments leads to changes in shape and contour. Folds, in contrast, occur at transition points between thick and thinner superficial fat compartments. These anatomical observations further the goal of site-specific augmentation and facial rejuvenation.

Three- and four-dimensional computed tomographic angiography and venography for the investigation of the vascular anatomy and perfusion of perforator flaps.

Background: Two-dimensional contrast radiography is the current standard for investigating the vascular anatomy of surgical flaps. The microvascular anatomy of the perforator flap, however, is limited conceptually by representation in two dimensions. Static three-dimensional computed tomographic angiography enables vascular anatomy to be evaluated in the coronal, axial, and sagittal planes, and dynamic four-dimensional computed tomographic angiography allows the vascular filling of a perforator flap to be visualized over short time intervals in three dimensions. Methods: An anatomical study was performed using 11 fresh adult cadavers acquired through the Willed Body Program at the University of Texas Southwestern Medical Center, in Dallas, Texas. Four male and seven female cadavers were included in the study. Perforator flaps harvested included the following: anterolateral thigh, deep inferior epigastric perforator, superior gluteal artery perforator, inferior gluteal artery perforator, thoracodorsal artery perforator, anteromedial thigh, and dorsal intercostal artery perforator. Conclusions: Novel techniques for acquiring both static and dynamic three-dimensional images of macrovascular and microvascular perforator flap anatomy using computed tomographic angiography have been described. This methodology has also allowed the sequential investigation of adjacent vascular territories. This can provide a better understanding of how perforator flaps and the skin are perfused and may aid in the future design of new flaps.

Defining vascular supply and territory of thinned perforator flaps: part I. Anterolateral thigh perforator flap.

Background: The anterolateral thigh perforator flap is increasingly being used for trauma and reconstructive surgical cases. With the thinned flap design, greater survivability and a decrease in donor-site morbidity are observed. To increase our knowledge of the vascular territories in these flaps, an anatomic study was performed to determine pedicle number, location, and diameter; accompanying veins; vascular territory; and where surgical incisions can be made safely during thinning, as opposed to the “danger zone.” Methods: Thirteen anterolateral thigh perforator flaps were harvested from seven adult cadavers. The largest perforator arteries were cannulated, and flaps were thinned to a thickness of 6 to 8 mm, with a 2.5-cm radius from the perforator retained. Vascular territories were quantified before and after thinning by nonradiographic and radiographic methods. A series of dyes were injected: red dye for skin (photography) followed by Omnipaque for the whole flap (radiography) before thinning, and blue dye for skin (photography) and lead oxide for the whole flap (radiography) after thinning. Pedicle locations were determined by ratios of anatomical landmarks. Danger zone measurements were derived at specific thicknesses using lateral radiographs of each flap. Results: In anterolateral thigh perforator flaps, the mean perforator artery diameter at the fascia level was 1.00 ± 0.08 mm (range, 0.84 to 1.11 mm) and the mean number of perforator arteries was 1.69 ± 1.03 (±SD). Perforator pedicles were located near the midpoint of the line between the anterior superior iliac spine and the lateral aspect of the patella in the vertical axis. The mean vascular territories were 256 ± 52.5 cm2 (photography) and 351 ± 72.8 cm2 (radiography) in unthinned flaps and 211 ± 65.7 cm2 (photography) and 289 ± 106.6 cm2 (radiography) in thinned flaps. Differences in overall vascular territories after thinning were 83.3 percent (photography) and 81.8 percent (radiography) compared with unthinned flaps. Four respective vascular territory maps were drawn showing surgical territories using percentile confidence intervals (98th and 90th) and averages. From the skin at thicknesses of 4, 6, and 8 mm, the 98th percentile danger zones were 33 to 37 mm (proximal to distal), 30 to 35 mm, and 27 to 31 mm from the pedicle in the vertical axis, respectively; in the horizontal axis, they were 30 to 34 mm (medial to lateral), 28 to 31 mm, and 25 to 29 mm. Conclusions: These data define anterolateral thigh perforator flap pedicle location, number, and diameter before harvesting, surgical danger zones during thinning, and vascular territories after thinning. The authors’ guidelines provide surgeons with anatomical vascular territory maps to design and harvest specific flaps for optimal results.

Functional sympatholysis is impaired in hypertensive humans.

Non‐technical summary  In healthy individuals, blunting of the vasoconstriction caused by activation of the sympathetic nervous system is thought to be an important mechanism that optimizes blood flow to the working muscles. We show for the first time that this protective mechanism, called functional sympatholysis, is impaired in middle‐aged patients with high blood pressure. We also show that this impairment can be reversed by treatment with an angiotensin receptor blocker, but not with a thiazide‐type diuretic. These findings indicate that angiotensin II may augment sympathetic vasoconstriction in the active muscles of hypertensive humans, which may explain the exaggerated rise in blood pressure and blunted decline in systemic vascular resistance during exercise in this population.

Three- and four-dimensional computed tomographic angiography and venography of the anterolateral thigh perforator flap

Background: This study presents a detailed three- and four-dimensional appraisal of the arterial and venous anatomy and perfusion of the anterolateral thigh flap using a novel computed tomographic technique. Methods: Eighteen anterolateral thigh flaps harvested from fresh Western cadavers were used. Four-dimensional computed tomographic angiography with injection of iodinated contrast medium into isolated perforators and their venae comitantes was used to investigate the arterial and venous anatomy and flap perfusion. Additional perforators were injected to investigate the vascular connections within the flap. Changes in flap perfusion after thinning and adipofascial flap harvest were also examined, and contrast density within each flap plexus with respect to the perforator was examined. Results: Large-diameter linking vessels at the suprafascial level enabled perfusion of adjacent vascular territories and of the subdermal plexus between angiotomes. Thinning reduced the size of the vascular territory by ligating recurrent vessels at the level of the suprafascial plexus. Adipofascial flap harvest prevented perfusion of the recurrent vessels, demonstrating the role of the subdermal plexus in recurrent flow. Three distinct perforator complex patterns were found with relevance to flap thinning. A superficial venous system perfused the venae comitantes of the descending branch of the lateral femoral circumflex artery and the long saphenous vein. Conclusions: A reduction in vascular territory occurs in the anterolateral thigh flap after thinning and is attributable to ligation of vessels within the suprafascial plexus. Recurrent flow through the subdermal plexus was seen dynamically for the first time and appears to be an important mechanism for skin perfusion.

The single dominant medial row perforator DIEP flap in breast reconstruction: three-dimensional perforasome and clinical results.

Background: Successful outcomes with the deep inferior epigastric artery perforator (DIEP) flap are heavily dependent on identifying the largest perforators. The purpose of this study was to describe the vascular anatomy (location, size, zones of perfusion, and variations) of the single most dominant deep inferior epigastric artery perforator and to report a clinical series based on this flap. Methods: Eleven abdominal flaps were harvested from fresh adult cadavers, and measurements were combined with clinical measurements from 16 patients. Details such as perforator size, location, type, and zones of perfusion were documented for all flaps and clinical outcomes for all patients. Results: A total of 36 flaps were dissected with an average perforator location within a 3-cm radius of the umbilicus and an average perforator size greater than 1.8 mm. Computed tomographic scans of the cadaver abdominal flaps demonstrated consistent perfusion in zones I and II and half of zones III and IV. Clinical results showed partial flap necrosis in one patient and fat necrosis of less than 5 percent in three patients, all of which occurred in the distal portion of zone III. The deep inferior epigastric artery medial row perforators near the umbilicus were found to be the largest perforators in the entire deep inferior epigastric artery system and abdomen. Conclusions: The single dominant medial row perforator has a maximal vascularity in zones I and II, and less in zones III an IV. The authors recommend that half of zone III and all of zone IV be discarded to avoid the risks of partial flap loss and fat necrosis.

Three- and four-dimensional computed tomography angiographic studies of commonly used abdominal flaps in breast reconstruction.

Background: The innovative technique of three- and four-dimensional computed tomographic angiography allows us to analyze the areas of perfusion in commonly used free abdominal flaps in breast reconstruction, such as pedicled transverse rectus abdominis musculocutaneous (TRAM) flaps, full TRAMs, muscle-sparing TRAMs, and deep inferior epigastric perforator (DIEP) flaps. The authors compared the vascular territories in these flaps. Methods: A total of 11 lower abdominal flaps were obtained from nine cadavers and two abdominoplasty procedures. The authors simulated the perfusion of seven pedicled TRAMs, eight full TRAMs, eight muscle-sparing TRAMs, 14 DIEPs, and six superficial inferior epigastric artery flaps. For each simulated flap, the named artery/perforator was injected with Omnipaque contrast using a Harvard precision pump at 0.5 ml/minute, and the flap was subjected to dynamic computed tomographic scanning using a GE Lightspeed 16-slice scanner. Scans were repeated at 0.125-ml increments (every 15 seconds) for the first 1 ml, then at 0.5-ml increments (every 60 seconds) for the next 2 to 3 ml, thus giving progressive computed tomographic images over time. Images were viewed using both General Electrics and TeraRecon systems, allowing analysis of branching patterns and perfusion flow as well as measurements of vascular territory. Conclusions: This study shows that there are definitive differences in vascular territory based on flap type. The sequences of images also allow us to reappraise the classic Hartrampf zones of perfusion.

A randomized, double-blinded, placebo-controlled pilot trial of anticoagulation in low-risk traumatic brain injury: The Delayed Versus Early Enoxaparin Prophylaxis I (DEEP I) study.

BACKGROUND Our group has created an algorithm for venous thromboembolism prophylaxis after traumatic brain injury (TBI), which stratifies patients into low, moderate, and high risk for spontaneous injury progression and tailors a prophylaxis regimen to each arm. We present the results of the Delayed Versus Early Enoxaparin Prophylaxis I study, a double-blind, placebo-controlled, randomized pilot trial on the low-risk arm. METHODS In this two-institution study, patients presenting within 6 hours of injury with prespecified small TBI patterns and stable scans at 24 hours after injury were randomized to receive enoxaparin 30 mg bid or placebo from 24 to 96 hours after injury in a double-blind fashion. An additional computed tomography scan was obtained on all subjects 24 hours after starting treatment (and therefore 48 hours after injury). The primary end point was the radiographic worsening of TBI; secondary end points were venous thromboembolism occurrence and extracranial hemorrhagic complications. RESULTS A total of 683 consecutive patients with TBI were screened during the 28 center months. The most common exclusions were for injuries larger than the prespecified criteria (n = 199) and preinjury anticoagulant use (n = 138). Sixty-two patients were randomized to enoxaparin (n = 34) or placebo (n = 28). Subclinical, radiographic TBI progression rates on the scans performed 48 hours after injury and 24 hours after start of treatment were 5.9% (95% confidence interval [CI], 0.7–19.7%) for enoxaparin and 3.6% (95% CI, 0.1–18.3%) for placebo, a treatment effect difference of 2.3% (95% CI, −14.42–16.5%). No clinical TBI progressions occurred. One deep vein thrombosis occurred in the placebo arm. CONCLUSION TBI progression rates after starting enoxaparin in small, stable injuries 24 hours after injury are similar to those of placebo and are subclinical. The next Delayed Versus Early Enoxaparin Prophylaxis studies will assess efficacy of this practice in a powered study on the low-risk arm and a pilot trial of safety of a 72-hour time point in the moderate-risk arm. LEVEL OF EVIDENCE Therapeutic study, level II.

The Extended Anterolateral Thigh Flap: Anatomical Basis and Clinical Experience

Background: Reports suggest that the anterolateral thigh flap can be reliably extended to include adjacent vascular territories. The vascular basis of this phenomenon is poorly understood. This study examines the three- and four-dimensional arterial and venous anatomy of the extended anterolateral thigh flap and reports the results of a clinical series of extended anterolateral thigh flaps. Methods: Fifteen anterior hemithigh specimens harvested from fresh cadavers from the Western population were studied. Four-dimensional computed tomographic angiography was used to investigate the arterial and venous anatomy and pattern of perfusion. Injection of perforators within the lateral femoral circumflex femoral vascular territory, and those of the common femoral and superficial femoral arteries, was performed to investigate the vascular connections within the extended anterolateral thigh flap. Static three-dimensional imaging and latex dissections were also performed to confirm the results. A clinical series of 12 consecutive patients is also reported in which extended anterolateral thigh flaps were used for posttrauma or postoncologic reconstruction. Results: Large-diameter linking vessels at the suprafascial level enabled perfusion of the adjacent common femoral and superficial femoral artery vascular territories. In the clinical series, the flap cutaneous territory ranged from 250 to 630 cm2 (mean, 365 cm2), with all flaps except one perfused by a single perforator. No partial or complete flap losses occurred. Conclusions: This study reports the vascular basis and clinical safety of the extended anterolateral thigh flap, which can be harvested if the linking vessels between adjacent vascular territories in the anterior thigh are preserved. The extended flap is reliably perfused by a single dominant perforator.