The End-to-Side Anastomosis: A Comparative Analysis of Arterial Models in the Rat
Item Type Thesis; Poster; text
Authors Kaur, Pareena
Publisher The University of Arizona.
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Link to Item http://hdl.handle.net/10150/658261 THE END-TO-SIDE ANASTOMOSIS: A COMPARATIVE ANALYSIS OF ARTERIAL
MODELS IN THE RAT
A thesis submitted to the University of Arizona College of Medicine – Phoenix in partial fulfillment of the requirements for the Degree of Doctor of Medicine
Pareena Kaur
Class of 2021
Mentor: Mark Preul, MD Arterial End-to-side Anastomosis Models in Rat 2
33 ABSTRACT 34 Background: The end-to-side anastomosis is one of the most common anastomosis 35 configurations used in cerebrovascular surgery. Whereas several living practice models have 36 been proposed for this technique, few involve purely arterial vessels. 37 Objective: The purpose of this study is to compare two arterial models using common carotid 38 (CCA) and common iliac arteries (CIA) in rats. 39 Methods: CIAs and CCAs were exposed in 10 anesthetized rats with their lengths and diameters 40 measured. Also, the mobilization extent of each vessel along its contralateral counterpart was 41 measured after each artery was transected at its proximal exposure point. We also studied the 42 technical advantages and disadvantages of each model for practicing end-to-side anastomosis. 43 Results: The average diameters of the CCA and CIA were 1.1mm and 1.3mm, respectively. The 44 average extents of mobilization along the contralateral vessel were 13.9mm and 10.3mm for 45 CCA and CIA, respectively. The CCA model had the advantages of more arterial redundancy 46 (allowing completing both suture lines extraluminally) and minimal risk of venous injury. The 47 main disadvantage of the CCA model was risk of cerebral ischemia. The CIA model was not 48 limited by ischemia time and provided the technical challenge of microsurgical dissection of the 49 common iliac vein from the CIA, while suffering from limited CIA redundancy. 50 Conclusion: Both CCA and CIA models could be efficiency used for practicing the end-to-side 51 anastomosis technique. Each provides the trainee with a specific set of advantages and 52 disadvantages that could help with optimal selection of the practice model based on trainee’s 53 skill level. 54 55 56 Keywords: Bypass surgery; Cerebral revascularization; End-to-side anastomosis; Microvascular 57 anastomosis; Rodent surgery. 58 Short Title: Arterial End-to-side Anastomosis Models in Rat 59 60 61 62 63 Arterial End-to-side Anastomosis Models in Rat 3
64 Introduction 65 The end-to-side anastomosis is one of the most common anastomoses used in 66 cerebrovascular surgery. The superficial temporal-to-middle cerebral artery bypass is the 67 prototype of this configuration and is probably the most commonly used cerebral bypass 68 procedure performed using this technique.1-3 The reimplantation technique is an intracranial- 69 intracranial bypass which is commonly used in the surgical management of complex lesions and 70 involves the end-to-side anastomosis.3-6 Also, many interpositional grafting bypass procedures 71 use the same configuration.3,7 Therefore, achieving proficiency in performing this anastomosis is 72 fundamental for cerebrovascular surgeons. Whereas many non-living models, such as silicone 73 tubes, placenta, and chicken and turkey wing vessels are being used for this purpose, they do not 74 substitute for the high-fidelity living models.8-11 These living models have get the trainee one 75 step closer to the real intraoperative situations as they provide live hemodynamics as well as 76 management practice of coagulation and vessel physiology.12-16 77 Rat common carotid arteries (CCA) have been used to practice the end-to-side 78 anastomosis.12,17,18 Some other rodent models include the portocaval anastomosis, anastomosis of 79 the iliolumbar vein to the side of the inferior vena cava (IVC), and the end-to-side anastomosis 80 between rat CCA and external jugular vein (EJV).12,14,19-21 Unfortunately, practice models 81 involving veins do not simulate the pure arterial anastomoses performed in cerebrovascular 82 surgery. We have proposed the use of rat common iliac arteries (CIA) for practicing end-to-side 83 anastomosis.22 The purpose of this study is to compare the two arterial models (CCA versus 84 CIA) for end-to-side anastomosis in rat to identify their relative advantages and disadvantages, 85 and help trainees select the proper practice model that best meets their learning objectives. 86 87 Methods 88 Ten Sprague-Dawley rats weighing >350g were anesthetized to undergo surgery 89 according to the protocol approved by the Institutional Animal Care and Use Committee 90 (IACUC) and all animals were managed according to USDA and NIH guidelines. Intermittent 91 (every 30-45 minutes) intramuscular injections of a combination of xylazine (5mg/kg), 92 acepromazine (1.0mg/kg) and ketamine (50mg/kg) were used to induce and maintain anesthesia. 93 To avoid hypothermia and hypoxia, heat source and oxygen supplementation (through a nose 94 cone) were provided, respectively. Arterial End-to-side Anastomosis Models in Rat 4
95 96 Exposure of CIA 97 Through a midline abdominal incision, the retroperitoneal region was exposed as 98 described elsewhere.23 A Pentero 800 surgical microscope (Carl Zeiss AG, Oberkochen, 99 Germany) was used to dissect bilateral CIAs from the encasing connective tissue and adjacent 100 common iliac veins (CIV). The CIAs were exposed from origin to their distal bifurcation into 101 internal and external iliac arteries. The diameters and lengths of the exposed CIAs were 102 measured. Also, we measured the distance between the two arteries at their distal exposure point 103 (Figure 1A). 104 105 End-to-Side Anastomosis between CIAs 106 Temporary clips were placed proximally and distally on each CIA. The right CIA was cut 107 just distal to the proximal clip (Figure 1A). The arterial stump was then mobilized inferiorly 108 along the left CIA to assess the inferior-most point it could be anastomosed onto the left CIA 109 without unacceptable tension. The point of maximum mobilization was marked and the length of 110 left CIA was measured from its origin to this point. The donor and recipient arteries were 111 prepared by removing adventitia from the estimated regions of anastomosis. Next, the right CIA 112 stump was prepared by performing the fish-mouthing technique (Figure 1B-C).7 A linear 113 arteriotomy was also performed on the left CIA with a length almost twice the diameter of the 114 artery (Figure 1D). Heel and toe stitches were first passed and tied (Figure 1E-F). As such, two 115 suture lines were created between the apposed arteries: superficial and deep. At this point, 116 redundancy of the right CIA was assessed to determine the feasibility of rolling the right CIA 117 around the longitudinal axis of left CIA, such that the deep suture line could be visualized and 118 completed extraluminally. When such maneuver put undue tension on the right CIA, the deep 119 edges of the arteries were sutured using an intraluminal technique (Figure 1G; also See video, 120 Supplemental Digital Content 1 which shows the end-to-side anastomosis performed between the 121 two CIAs). The superficial suture line was completed in the usual extraluminal fashion (Figure 122 1H), and the temporary clips were removed (except the one on right proximal CIA) to reinstate 123 flow in both CIAs (Figure 1I). The abdominal viscera were then returned to the abdominal cavity 124 and the surgical incision was covered with wet gauze to mitigate insensible water loss during the 125 following stages of surgery. Arterial End-to-side Anastomosis Models in Rat 5
126 127 Exposure of CCA 128 Bilateral CCAs were exposed via a midline cervical incision as described previously.24 129 Using microsurgical techniques, the carotid sheath was opened and the CCAs were dissected off 130 the accompanying vagus nerve and sympathetic trunk bilaterally. Diameter and length of 131 exposed CCAs were recorded. Additionally, the distance between the two CCAs was measured 132 at mid-cervical level. 133 134 End-to-Side Anastomosis Between CCAs 135 The CCAs were denuded from any covering adventitia. Proximal and distal clips were 136 placed on both CCAs. Next, the right CCA was cut just distal to the proximally applied clip 137 (Figure 2A). The feasibility of performing and end-to-side anastomosis between the CCAs was 138 assessed along the length of the left CCA. The distance between the most proximally exposed 139 point on the left CCA was measured from the distal-most and the proximal-most points onto 140 which the anastomosis was deemed feasible (Figure 2B-C). The arterial stump was then prepared 141 using the same technique described for preparation of the CIA (Figure 2D-E). An arteriotomy 142 was performed on the left CCA (Figure 2F), and the right CCA was reimplanted onto the left 143 CCA using a similar technique as for CIAs (Figure 2G-I). For each anastomosis, the feasibility 144 of extraluminally completing the deep suture line was assessed by checking the ability to rotate 145 the right CCA around the axis of left CCA (Figure 3). When such rotation was not possible or 146 put extreme tension on the right CCA, the deep suture line was completed intraluminally. 147 Bypass patency was assessed using the milking technique.12At the conclusion of surgery, 148 the technical features of exposure and performing end-to-side anastomosis using CIAs and CCAs 149 were recorded. The animals were euthanized following the approved IACUC protocol. 150 151 Statistical Analysis 152 Student’s t-test was used to compare independent parametric variables. 153 154 Results 155 End-to-Side Anastomosis Using CIAs Arterial End-to-side Anastomosis Models in Rat 6
156 End-to-side anastomosis was successfully completed between CIAs in all animals. Table 157 1 lists the results of measurements. 158 A thick connective tissue extended between the CIA and CIV, rendering the process of 159 CIA releasing relatively difficult (Figure 4A-B). Since the aortic bifurcation usually lay superior 160 to the confluence of the CIVs, dissection of the connective tissue running between the proximal 161 CIAs and the distal segment of IVC was also necessary (Figure 4C-D). Additionally, a 162 significant amount of adventitial tissue needed to be removed off the CIA to prepare it for 163 anastomosis (Figure 4E). With the large accompanying CIV and IVC, there was a considerable 164 risk of inadvertent venous injury and hemorrhage. Another anatomic finding was the presence of 165 multiple small side branches of the CIA running between the CIA and CIV (Figure 4F). 166 Identification and careful coagulation and division of these small twigs were necessary to 167 optimally prepare the CIAs and prevent arterial injury and subsequent hemorrhage. If these small 168 branches were not cut, the mobility of CIAs was further limited. The distal CIA bifurcation could 169 be easily identified by visualization of the genitofemoral nerve crossing the anterior aspect of 170 CIA within 5mm of CIA bifurcation (Figure 4G). 171 The right CIA could be mobilized along the left CIA for an average distance of 10.3±2.8 172 mm from the left CIA origin. When the right CIA was cut proximally, it retracted to almost1/3 173 of its originally length (approximately 6 mm). Due to the great amount of tension required to 174 rotate the right CIA stump around the left CIA, the deep suture line could not be completed 175 extraluminally in any of the animals. 176 177 End-to-side Anastomosis Using CCAs 178 Anastomosis was completed successfully in all animals. Table 1 lists the results of CCA 179 measurements as well as the results of statistical comparison between the CIA and CCA. 180 Following proximal transection of the right CCA, it retracted to almost 1/2 of the originally 181 exposed arterial length (approximately 10mm). The most distal point on left CCA onto which the 182 right CCA could be anastomosed was at an average distance of 19.4±2.6mm from the most 183 proximally exposed point on left CCA (Figure 2B). The most proximal point on left CCA onto 184 which the right CCA could be anastomosed was at an average distance of 5.5±1.6mm from the 185 most proximal point exposed on the left CCA (Figure 2C). When the right CCA was pulled 186 towards the left CCA, a relatively large amount of tension was required. However, we were able Arterial End-to-side Anastomosis Models in Rat 7
187 to visualize and complete the deep anastomosis line extraluminally by affixing the pulled right 188 CCA to the adjacent cervical muscles (Figure 3). This maneuver provided enough redundancy in 189 the right CCA stump so that it could be successfully rotated to visualize the deep arterial edges 190 from an extraluminal perspective –we have also included a supplemental video showing the 191 technique of completing the deep suture line intraluminally in CCAs (See video, Supplemental 192 Digital Content 2 which shows end-to-side anastomosis between CCAs). Average ischemia time 193 was 34±4.5 minutes. We did not encounter any unintended premature animal deaths during 194 cerebral ischemia time. 195 The CCA had less adventitial tissue compared to the CIA (Figure 5A). This facilitated the 196 exposure and preparation of the CCA. Although the EJVs were exposed during superficial neck 197 dissection, no major vein accompanied the CCA during dissection of the carotid sheath. 198 Additionally, CCA had no branches. Therefore, the risk of vascular injury and severe 199 hemorrhage was minimal. However, caution was needed to safely dissect the CCA from the 200 accompanying sympathetic trunk and vagus nerve within the carotid sheath (Figure 5B). 201 202 Discussion 203 We have shown that both CCA and CIA models could be used to practice the end-to-side 204 anastomosis technique. Each model had relative advantageous and disadvantages that could be 205 considered in a practice protocol based on the skill level of the trainee (Table 2). 206 207 The CIA End-to-Side Anastomosis Model 208 Using CIAs for practicing end-to-side anastomosis has several advantages compared to 209 CCAs. First, as CIAs do not supply vital tissues, clamping the CIAs could be tolerated for 210 extended periods of time. Therefore, less experienced trainees may spend extended amounts of 211 time during anastomosis of CIAs to achieve proficiency without the impending risk of animal 212 death from cerebral ischemia. 213 Another advantage of the CIA model is the technical challenge it provides. As mentioned 214 before, CIA, CIV, and IVC are intimately invested with a relatively dense connective tissue 215 (Figure 4A-D). The accompanying CIVs and IVC are large fragile vessels. Releasing the CIA 216 and its preparation for anastomosis requires microsurgical dissection near the CIV and IVC.23 217 This technical challenge supports the trainees with developing fine microsurgical skills. A Arterial End-to-side Anastomosis Models in Rat 8
218 similar challenge is frequently encountered when an intracranial recipient vessel needs to be 219 released from the surrounding vessels and arachnoid adhesions. A familiar example is releasing
220 and preparing an M4 branch of the middle cerebral artery for a superficial temporal artery to 221 middle cerebral artery bypass.25,26 However, this feature may be seen as a disadvantage of the 222 CIA model by less experienced trainees. A minor puncture site on the CIV could cause extensive 223 bleeding which may be difficult to control, and lead to unintended premature animal death. 224 The CIA model has several disadvantages. First, the adventitial tissue around the CIA is 225 bulky and requires extra work with caution for preparation while avoiding arterial wall damage 226 (See and compare Figures 4E and 5A) (Also see and compare videos, supplemental digital 227 contents 1 and 2 which show end-to-side anastomosis between CIAs and CCAs, respectively). 228 Another disadvantage is the extreme tension applied to the arteries while the approximation is 229 being performed. This tension results from the short length of the CIA arterial stump. After 230 cutting the CIA proximally, it retracts to almost 1/3 of its original length (approximately 6 mm). 231 This length is significantly smaller than the minimum distance between the distal-most point 232 exposed on the right CIA and the contralateral CIA (15mm) (Figure 6). Therefore, this artery 233 should be stretched more than twice as its shortened length to reach the contralateral CIA. These 234 calculations support our observations about the lack of enough redundancy of the left CIA stump 235 to enable flipping the artery and visualizing the deep arterial edges extraluminally. Therefore, we 236 needed to complete the deep suture line intraluminally in all animals (Figure 1, See video, 237 Supplemental Digital Content 1 which shows the end-to-side anastomosis performed between the 238 two CIAs). This is contrary to the usual technique used to perform end-to-side anastomosis 239 where both suture lines are usually completed extraluminally.7 However, this specific technique 240 for end-to-side anastomosis has been previously introduced and used when limited redundancy 241 restricts rotation of one artery around the other.22,25 242 Another disadvantage of the CIA model is the need to manage tiny branches of CIA that 243 run between the CIA and CIV (Figure 4F). These branches should be carefully dissected, 244 coagulated, and cut to prepare the CIA. Failure to efficiently control these branches may cause 245 bleeding and/or inadequate preparation of the CIA leading to suboptimal mobility of the arterial 246 tissues during anastomosis. 247 248 The CCA End-to-Side Anastomosis Model Arterial End-to-side Anastomosis Models in Rat 9
249 As mentioned above, the CCA is not accompanied by major venous structures. Therefore, 250 the risk of venous injury is less with CCAs. Furthermore, the CCA does not have any side 251 branch; a feature that facilitates its preparation for anastomosis. Additionally, compared to CIA, 252 the CCA suffered from less length shortening after transection, and had adequate redundancy to 253 enable an extraluminal completion of both suture lines (Figure 3). 254 On the other hand, the CCA model has some disadvantages. First, cerebral ischemia 255 during clamp time can cause stroke or animal death. Although we did not observe any animal 256 deaths during an average of 34 minutes of bilateral CCA clamping, we are unable to comment on 257 stroke rates because we did not perform survival surgeries. This point is important for less 258 experienced trainees that need extended periods of carotid clamping to complete the 259 anastomosis. On the other hand, the same feature of limited ischemia time for CCAs could be 260 considered an advantage for more experienced trainees; adding the limitation of ischemia time 261 can help advanced trainees refine their techniques and avoid unnecessary maneuvers as they are 262 encouraged to shorten the overall anastomosis procedure time. 263 Of note, there are two nerve trunks in the carotid sheath which should be preserved.24 264 Vagus nerve injury could cause laryngeal muscle paralysis and asphyxiation during or after 265 surgery. Injury to the sympathetic trunk could theoretically cause changes in sympathetic 266 outflow affecting systemic vascular tone and heart rate. Therefore, these structures should be 267 carefully preserved during exposure of the CCAs. Ikeda et al have also mentioned the possibility 268 of tracheal compression by the approximated CCAs that could cause airway compromise.27 269 270 Conclusion 271 Rat CCA and CIA could be efficiently used to practice the end-to-side anastomosis 272 technique. Each model offers several advantages and provides different learning challenges to 273 the trainee. This study analyzed these advantages and disadvantages to help surgeons with 274 optimal selection of the practice model based on their skill level. 275
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278 Arterial End-to-side Anastomosis Models in Rat 10
279 Figure Legends 280 Figure 1. Technique of end-to-side anastomosis between bilateral CIAs. A, showing the 281 exposure of distal AA and bilateral CIAs with clips applied distally and proximally to CIAs. The 282 distance between the distal points exposed on CIAs was measured (double-arrowed dashed line). 283 Arrowhead marks to the transection point on the right CIA. B-C, the fish-mouthing technique. 284 After an oblique transection (at 60 degrees) of the right CIA stump, a longitudinal cut (white 285 arrowhead in C) with the same size of the oblique cut is placed at the sidewall of the vessel to 286 enlarge the arterial orifice and change its cross-sectional shape from an ellipsoid to a 287 quadrangular configuration. D, a longitudinal arteriotomy is performed at the mid-portion of the 288 left CIA almost twice the diameter of the artery (double-arrowed line). E, heel and toe stitches 289 are passed through both recipient and donor arterial walls such that the knots are at the 290 extraluminal side (F). G, the deep suture line is completed intraluminally, as extreme tension on 291 the right CIA does not allow its free rotation around the longitudinal axis of the left CIA. H, the 292 superficial suture line is completed extraluminally. I, the completed bypass with the right CIA 293 reimplanted onto the left CIA. AA = abdominal aorta; CIA = common iliac artery; L = left; R = 294 right. 295 Figure 2. Technique of end-to-side anastomosis between bilateral CCAs. A, CCAs are exposed 296 through a midline neck incision. Vascular clips are placed proximally and distally. The right 297 CCA is transected just distal to the proximal clip (black arrowhead). Please note that the 298 transected CCA retracts and shortens to almost ½ of its initial length. B and C, assessment of the 299 mobilization extent of the right CCA for an end-to-side anastomosis to the left CCA. The right 300 CCA is mobilized along the left CCA distally (B) and proximally (C) to assess its maximal distal 301 and proximal excursion relative to the proximally exposed point on the CCA (double-arrowed 302 lines). Oblique transection (D) and fish-mouthing (E) of the arterial stump of the right CCA. F, 303 linear arteriotomy on the left CCA almost twice the diameter of the CCA. Passing (G) and tying 304 (H) heel and toe stitches. I, completed bypass with the right CCA reimplanted onto the left CCA. 305 CCA = common carotid artery; med. = medial; prox. = proximal. 306 Figure 3. Technique of completing the deep suture line extraluminally during end-to-side 307 anastomosis between CCAs. A, the right CCA is exposed and ligated proximally. B, the left 308 CCA is also exposed and clipped proximally and distally. Using multiple clips, the right CCA is 309 mobilized across the midline and anchored to the midline subhyoid muscles to have maximum Arterial End-to-side Anastomosis Models in Rat 11
310 redundancy during the end-to-side anastomosis with the left CCA. C, this redundancy allows 311 completing the deep suture line extraluminally (white arrowhead). D, completed bypass. CCA = 312 common carotid artery; R = right; sup. = superior. 313 Figure 4. Anatomical nuances of exposing CIAs in preparation for the end-to-side anastomosis 314 technique. A-B, there is a thick connective tissue running between the CIA and CIV that needs to 315 be dissected under microscopic magnification. This thick connective tissue also exists between 316 the proximal CIAs and the distal segment of IVC (C-D). E, heavy adventitial tissue (black 317 arrowhead) around the CIA should be carefully and atraumatically removed to prepare the artery 318 for anastomosis. F, small arterial twigs of the CIA (small arrows) that run in close proximity of 319 the CIV should be carefully exposed, coagulated, and divided to fully prepare the CIA for a 320 bypass. Failure to efficiently control these small branches may lead to bleeding and/or limited 321 mobility of the CIA. G, the distal bifurcation of the CIA (small arrow) may be easily identified 322 by the genitofemoral nerve crossing the anterior aspect of the CIA close to its bifurcation into 323 external and internal iliac arteries. AoB = aortic bifurcation; CIA = common iliac artery; CIV = 324 common iliac vein; IVC = inferior vena cava; n. = nerve. 325 326 Figure 5. Anatomical nuances of exposing CIAs in preparation for the end-to-side anastomosis 327 technique. A, please note the light adventitial covering of the CCA (white arrowhead) and 328 compare it with the CIA. B, the sympathetic trunk and vagus nerve are the major structures 329 accompanying the CCA within the carotid sheath. These structures should be carefully exposed, 330 protected, and dissected from the CCA. CCA = common carotid artery; med. = medial; n. = 331 nerve; prox. = proximal; tr. = trunk. 332 Figure 6. The geometry of end-to-side anastomosis between CIAs. Based on our results, the 333 distances between the aortic bifurcation (point A), and left (point B) and right CIA bifurcations 334 (point C) are almost equal (approximately 17mm); hence the ABC triangle is an isosceles 335 triangle. Therefore, according to the Pythagorean theorem, the shortest distance between the 336 stump of one CIA and the other CIA is approximately 15 mm. 337 338 339 340 Arterial End-to-side Anastomosis Models in Rat 12
341 Supplemental Digital Content Legends 342 Supplemental Digital Content 1. Video demonstrating the end-to-side anastomosis model using 343 rat common iliac arteries. 344 00:09 exposed common iliac arteries 345 00:18 clipping 346 00:29 proximal transection and preparation of right common iliac artery 347 01:31 arteriotomy of left common iliac artery 348 02:03 end-to-side anastomosis 349 08:11 clip removal and reinstatement of blood flow 350 08:53 assessment of bypass patency using milking technique 351 352 Supplemental Digital Content 2. Video demonstrating the end-to-side anastomosis model using 353 rat common carotid arteries. 354 00:09 exposed common carotid arteries 355 00:15 clipping 356 00:25 proximal transection and preparation of right common carotid artery 357 01:37 arteriotomy of left common carotid artery 358 02:02 end-to-side anastomosis 359 06:25 clip removal and reinstatement of blood flow 360 06:53 assessment of bypass patency using milking technique 361 362 363 364 365 366 367 368 369 370 371 Arterial End-to-side Anastomosis Models in Rat 13
372 Disclosures: 373 This study was supported by Barrow Neurological Foundation support to Dr. Tayebi, and from 374 the Newsome Chair in Neurosurgery Research held by Dr. Preul. 375 376 Previous Presentation 377 None. 378 379 Acknowledgments: We are grateful to the Barrow Neurological Foundation and to the 380 Newsome Chair in Neurosurgery Research held by Dr. Preul for funding for this project. The 381 authors also thank Ms. Marie Clarkson from Barrow Neurological Institute Neuroscience 382 Publications for her assistance with preparation and editing of the supplemental digital contents. 383 384
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Table 1. measurements performed on CIA and CCA. Variable CIA CCA P-value# Diameter 1.3 ± 0.1† 1.1 ± 0.2 0.08 Exposed Length 17.2 ± 1.2 20.4 ± 2.5 < 0.001 Mobilization Extent 10.3 ± 2.8 13.9 ± 2.8 0.01 Distance between 17.0 ± 1.6 12.5 ± 0.7 < 0.001 bilateral vessels # Student’s t-test for independent parametric variables
†All results are presented in millimeters as mean ± standard deviation
Table 2 Click here to download Table(s): Table 2.docx
Table 2. Comparison of the CCA and CIA anastomosis models Anastomosis Advantages Disadvantages Model CCA Minimal risk of major venous Risk of injury to sympathetic trunk injury/hemorrhage and/or vagus nerve Favorable redundancy of CCAs Risk of stroke or animal death during (possibility of completing the deep clamp time† suture line extraluminally) Risk of tracheal compression by the Absence of side branches of CCA juxtaposed CCAs Minimal amount of adventitial tissue CIA No ischemia time High tension required to approximate Providing the challenge of arteries microsurgical release of the CIA from Not possible to complete the deep CIV † suture line extraluminally† Risk of major venous hemorrhage leading to animal death† Tiny branches of CIA should be effectively exposed, coagulated, and cut Bulky adventitia
†These are considered wildcard features as they may be considered advantageous or disadvantageous according to the skill level of the trainee
Figure 1 Click here to download high resolution image Figure 2 Click here to download high resolution image Figure 3 Click here to download high resolution image Figure 4 Click here to download high resolution image Figure 5 Click here to download high resolution image Figure 6 Click here to download high resolution image Supplementary Material (Video 1) Click here to download Supplementary Material (Video/Media Files): CIA end-to-side_blind.mp4
Supplementary Material (Video 2) Click here to download Supplementary Material (Video/Media Files): CCA end-to-side_blind.mp4