Critical Ischemia Time Research Articles

Comparison of total anastomosis time between four different combinations of suturing and knot tying techniques in microsurgical anastomosis

Background Various techniques have been described for performing microsurgical anastomosis with providing high patency rates. Although the total anastomotic time may not be an issue when dealing with a single set of anastomoses, using a faster technique may save significant amount of time in cases of transferring flaps with shorter critical ischemia time or where multiple anastomoses are required. This study compares the total anastomosis time between four different combinations of commonly used suturing and knot tying techniques. Methods Twenty-four rats were divided into 4 groups. Simple interrupted suture with conventional knot tying technique (SIS-CT) was used in group I, continuous suture technique with conventional knot tying (CST) was used in group II, simple interrupted suture with airborne knot tying technique(SIS-AT) was used in group III, and continuous-interrupted suture with airborne knot tying technique(CIS-AT) was used in group IV for microsurgical anastomosis. Total anastomosis time and patency rates with each technique and samples from anastomotic sites were analyzed. Results The mean time required for microvascular anastomosis of the femoral artery was 1075 s in group I, 799 s in group II, 844 s in group III, and 973 s in group IV. The difference between four groups was statistically significant. The anastomoses in group II and group III were completed in the shortest period of time. Intergroup comparison revealed that the difference between group II and group III was not statistically significant, however, total anastomosis time for completion of the anastomosis was significantly longer for group I, followed by group IV. Thrombosis rates and histological analysis revealed no significant differences among four groups. Conclusion CST and SIS-AT techniques can significantly reduce microsurgical anastomosis time and provide high patency rates. Also, the time needed to complete an anastomosis was significantly shorter for CIS-AT when compared to SIS-CT.

Long-term outcomes of arterial ischemia or venous occlusion on vascularized groin lymph nodes in a rat model.

This study investigated the long-term effects of arterial ischemia and venous occlusion on lymph node drainage function in a rat model. Bilateral groin lymph node flaps of 18 Lewis rats were dissected. The pedicle artery was clamped for 4, 5, and 6 h (A4, A5, and A6 groups), and the vein for 3, 4, and 5 h (V3, V4, and V5 groups) in six flaps. At 4 weeks, the evaluations included gross morphomics, indocyanine green (ICG) lymphography, histological section, immunofluorescence of terminal deoxynucleotidyl transferase assay, and heme oxygenase-1 (HO-1) stain. The lymph node flaps developed shrinkage and partial necrosis in A5, A6, V4, and V5 groups. Hemorrhage in the lymph node cortex and medulla was observed histologically in A5, A6, and V5 groups. ICG lymphography showed loss of lymphatic drainage function in 2 of 6 flaps in A6 and V5 groups. Cell death was shown partly in cortical follicles in A5 and V4 groups and completely in A6 and V5 groups. The HO-1 expression was statistically increased in A5 and V5 groups, respectively (p < 0.05). The critical arterial ischemia and venous occlusion time were 4 h at 4 weeks of follow-up.

Critical warm ischemia time point for cardiac donation after circulatory death

Donation after circulatory death (DCD) represents a promising opportunity to overcome the relative shortage of donors for heart transplantation. However, the necessary period of warm ischemia is a concern. This study aims to determine the critical warm ischemia time based on in vivo biochemical changes. Sixteen DCD non‐cardiac donors, without cardiovascular disease, underwent serial endomyocardial biopsies immediately before withdrawal of life‐sustaining therapy (WLST), at circulatory arrest (CA) and every 2 min thereafter. Samples were processed into representative pools to assess calcium homeostasis, mitochondrial function and cellular viability. Compared to baseline, no significant deterioration was observed in any studied parameter at the time of CA (median: 9 min; IQR: 7–13 min; range: 4–19 min). Ten min after CA, phosphorylation of cAMP‐dependent protein kinase‐A on Thr197 and SERCA2 decreased markedly; and parallelly, mitochondrial complex II and IV activities decreased, and caspase 3/7 activity raised significantly. These results did not differ when donors with higher WLST to CA times (≥9 min) were analyzed separately. In human cardiomyocytes, the period from WLST to CA and the first 10 min after CA were not associated with a significant compromise in cellular function or viability. These findings may help to incorporate DCD into heart transplant programs.

Comparison between Digital Subtraction Angiography and Indocyanine Green Video Angiography in the Operative Management of Aneurysmal Subarachnoid Hemorrhage

Abstract Background Digital subtraction angiography (DSA) is a fluoroscopy technique used in interventional radiology to clearly visualize blood vessels in a bony or dense soft tissue environment. Images are produced using contrast medium by subtracting a “pre-contrast image” or mask from subsequent images, once the contrast medium has been introduced into a structure, hence the term “Digital subtraction angiography.” Indocyanine green video angiography (ICG-VA) is a safe and practical method of real-time delineation of microvasculature used in the surgical management of intracranial aneurysms, arteriovenous malformations, and other vascular lesions. Intraoperative ICG-VA is used as an adjunct in addition to intraoperative or postoperative DSA, and in other cases, it is used as the sole method to confirm the complete obliteration of clipped intracranial aneurysm. The only limitation of ICG-VA is the nonvisibility of vessels that are not in the operative field. Intraoperative ICG is useful in the clipping of intracranial aneurysms to ensure a gross patency of branch vessels; however, the presence of residual aneurysms and subtle changes in flow in branch vessels is best seen by DSA. Methods ICG angiography was done during the surgery and the findings of intraoperative ICG angiography were compared with postoperative DSA that was done between 6 and 12 weeks. DSA was done to see any compromise of lumen of parent vessel by clip, any residual aneurysm. Results In our study, intraoperative ICG complete aneurysm obliteration was present in all 30 (100%) patients, while in postoperative DSA complete aneurysm obliteration was diagnosed in 27 (90.0%) patients. Parent vessel patency was present in all 30 (100.0%) patients in both intraoperative ICG-VA and postoperative DSA. In intraoperative ICG distal branch patency was present in 26 (86.7%) patients, while in postoperative DSA distal branch patency was diagnosed in 27 (90.0%) patients. Conclusion We compared the intraoperative ICG finding and postoperative DSA finding and found that DSA is more sensitive than ICG in depicting residual aneurysm neck, hence reducing the risk of rupture of the aneurysm in future. Intraoperative ICG has high special resolution reflex feedback, intraoperative repositioning time is less and thus critical ischemia time is reduced. In a developing country like ours where DSA facilities are limited, ICG can be optimal investigation to delineate the vascular anatomy and confirmation of clip position thus reducing mortality.

Ex vivo limb perfusion for traumatic amputation in military medicine

BackgroundLimb loss has a drastic impact on a patient’s life. Severe trauma to the extremities is common in current military conflicts. Among other aspects, “life before limb” damage control surgery hinders immediate replantation within the short post-traumatic timeframe, which is limited in part by the ischemic time for successful replantation. Ex vivo limb perfusion is currently being researched in animal models and shows promising results for its application in human limb replantation and allotransplantation.Presentation of the hypothesisThe current lack of replantation possibilities in military operations with high rates of amputation can be addressed with the development of a portable ex vivo limb perfusion device, as there are several opportunities present with the introduction of this technique on the horizon. We hypothesize that ex vivo limb perfusion will enable overcoming the critical ischemic time, provide surgical opportunities such as preparation of the stump and limb, allow for spare-part surgery, enable rigorous antibiotic treatment of the limb, reduce ischemia-reperfusion injuries, enable a tissue function assessment before replantation, and enable the development of large limb transplant programs.Testing the hypothesisData from in vivo studies in porcine models are limited by the relatively short perfusion time of 24 h. In the military setting, notably longer perfusion times need to be realized. Therefore, future animal studies must focus especially on long-term perfusion, since this represents the military setting, considering the time for stabilization of the patient until evacuation to a tertiary treatment center.Implications of the hypothesisThe development and clinical introduction of ex vivo limb perfusion in the military setting could lead to a drastic reduction in the number of limb amputations among service members. Ex vivo limb perfusion enables replantation surgery in Role 4 facilities and changes the clinical setting from a highly urgent, life-threatening situation to a highly methodical, well-prepared starting point for optimal treatment of the wounded service member. With its introduction, the principle of “life before limb” will change to “life before limb before elective replantation/allotransplantation after ex vivo limb perfusion”.

Critical Ischemia Time, Perfusion, and Drainage Function of Vascularized Lymph Nodes.

Vascularized lymph node transfer is a promising surgical treatment for lymphedema. This study investigated the effect of ischemia on the lymphatic drainage efficiency of vascularized lymph node flaps and the critical ischemia time of lymph nodes. Twenty-four lymph nodes containing groin flaps in 12 Sprague-Dawley rats were dissected. Clamping of the vascular pedicle was performed for 0, 1, 3, 5, 6, or 7 hours; then, each was allowed to reperfuse by means of the vascular pedicle for 1 hour. Perfusion and ischemic changes were assessed using indocyanine green lymphography; laser Doppler flowmetry; and histologic studies with associated lymphatic vessel endothelial hyaluronan receptor-1, CD68, 4',6-diamidino-2-phenylindole, terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling, and glutathione assay stains. The mean latency period of the groin lymph node flaps was 247 ± 67, 83 ± 15, 72 ± 42, 30 ± 18, and 245 ± 85 seconds in the 0-, 1-, 3-, 5-, and 6-hour groups, respectively. Perfusion detected by laser Doppler was 85.2 ± 14.5, 87.2 ± 36.7, 129.8 ± 33.7, 140.4 ± 148.5, 156.1 ± 91.4, and 41.2 ± 34.8 perfusion units at ischemia times of 0, 1, 3, 5, 6, and 7 hours, respectively. Cell damage measured by glutathione was 46.8 ± 10.2, 67.7 ± 14.2, 62.8 ± 15.4, 126.6 ± 5.9, 259.0 ± 70.3, and 109.1 ± 27.5 at ischemia times of 0, 1, 3, 5, 6, and 7 hours, respectively. Histologically, as ischemia time increased, hemorrhage and congestion became more severe. The critical ischemia time of vascularized lymph nodes is 5 hours in the rodent animal model, verified by indocyanine green lymphatic fluid uptake, laser Doppler perfusion, and histologic assessments. Interestingly, lymphatic drainage and perfusion of vascularized lymph nodes were improved with an increased ischemia time before the critical 5 hours was reached.

The Use of a Mechanical Stapler in Jejunal Free Flaps in Laryngopharyngectomy Defects.

The Use of a Mechanical Stapler in Jejunal Free Flaps in Laryngopharyngectomy Defects.

Novel Biomarkers of Arterial and Venous Ischemia in Microvascular Flaps

The field of reconstructive microsurgery is experiencing tremendous growth, as evidenced by recent advances in face and hand transplantation, lower limb salvage after trauma, and breast reconstruction. Common to all of these procedures is the creation of a nutrient vascular supply by microsurgical anastomosis between a single artery and vein. Complications related to occluded arterial inflow and obstructed venous outflow are not uncommon, and can result in irreversible tissue injury, necrosis, and flap loss. At times, these complications are challenging to clinically determine. Since early intervention with return to the operating room to re-establish arterial inflow or venous outflow is key to flap salvage, the accurate diagnosis of early stage complications is essential. To date, there are no biochemical markers or serum assays that can predict these complications. In this study, we utilized a rat model of flap ischemia in order to identify the transcriptional signatures of venous congestion and arterial ischemia. We found that the critical ischemia time for the superficial inferior epigastric fasciocutaneus flap was four hours and therefore performed detailed analyses at this time point. Histolgical analysis confirmed significant differences between arterial and venous ischemia. The transcriptome of ischemic, congested, and control flap tissues was deciphered by performing Affymetrix microarray analysis and verified by qRT-PCR. Principal component analysis revealed that arterial ischemia and venous congestion were characterized by distinct transcriptomes. Arterial ischemia and venous congestion was characterized by 408 and 1536>2-fold differentially expressed genes, respectively. qRT-PCR was used to identify five candidate genes Prol1, Muc1, Fcnb, Il1b, and Vcsa1 to serve as biomarkers for flap failure in both arterial ischemia and venous congestion. Our data suggests that Prol1 and Vcsa1 may be specific indicators of venous congestion and allow clinicians to both diagnose and successfully treat microvascular complications before irreversible tissue damage and flap loss occurs.

Postoperative Monitoring in Free Muscle Transfers for Reconstruction in Brachial Plexus Injuries

Free gracilis transfers are done for reanimation of the upper limb in traumatic total brachial plexus palsy. Because of buried nature of the free muscle and monitoring skin flap in the axillary or infraclavicular region, it is always a tricky situation for continuous and repeated monitoring to assess vascular status. Critical ischemia times vary between the muscle and monitoring skin flap because of which signs of ischemic changes in the monitoring skin flap are always delayed with respect to the muscle. We describe a novel method that uses the principle of evoked potentials from the muscle to assess the vascular status of the free muscle and detects vascular compromise early before the skin changes are apparent.

Monitored Extended Secondary Arterial Ischemia in a Free Muscle Transfer

In reconstructive microsurgery, flap failure can be catastrophic to the patient. Different monitoring methods have been implemented in an attempt to recognize secondary ischemia during its early stages. However, the exact onset of secondary ischemia can be difficult to determine because there are no well-documented and reliable monitoring techniques that offer true continuous monitoring in a clinical setting. Because of the uncertain time in terms of the onset of secondary ischemia, the exact length of ischemia before revascularization, the secondary ischemia time, cannot be obtained. This is probably part of the reason why not much has been published regarding the effect of secondary ischemia time in reference to flap survival. We present a case of a free gracilis muscle flap that was salvaged despite more than 11 hours of arterial ischemia. The flap was monitored using microdialysis and at no time was the ischemia clearly demonstrated by clinical inspection. We conclude that clinical monitoring in some cases can be an unreliable method for monitoring free muscle transfers suffering from arterial ischemia and that further studies are needed for more specific guidelines regarding the critical secondary ischemia time in muscle flaps.

Does Ischemia Time Affect the Outcome of Free Fibula Flaps for Head and Neck Reconstruction? A Review of 116 Cases

The fibula osteoseptocutaneous flap is an excellent option for the reconstruction of segmental mandibular defects. This study was conducted to investigate the relationship between ischemia time and outcome of the fibula flap, thus establishing the critical ischemia time for this procedure. Between February of 2003 and March of 2005, 114 patients who underwent 116 fibular osteoseptocutaneous flaps for head and neck reconstruction were reviewed retrospectively. Complications were classified as acute, subacute, or chronic based on the time at which they were detected postoperatively. Outcomes among different ischemia time groups were evaluated: group A, less than 3 hours; group B, 3 to 4 hours; group C, 4 to 5 hours; and group D, 5 to 7 hours. The mean success rate of the fibula osteoseptocutaneous flap was 98.3 percent. Mean flap ischemia time was 3.6±0.97 hours. Sixty-six patients (56.9 percent) experienced one or more complications at different stages (86 complications total). There were no statistically significant differences in acute, subacute, and chronic complications among the four groups (p=0.6, p=0.6, and p=0.2, chi-square test). The overall complication rate was significantly higher in group D (81.8 percent) (p=0.03, chi-square test). The partial flap loss rate was also statistically higher in group D (45.5 percent) compared with the other three groups (12.1, 12.2, and 8.7 percent) (p=0.02, chi-square test). : Using the fibula osteoseptocutaneous flap for head and neck reconstruction, ischemia times less than 5 hours do not increase complication rates in different postoperative stages. However, the critical ischemia time of the fibula osteoseptocutaneous flap should be limited to 5 hours to reduce partial skin paddle loss and overall complications.

The Error of Omission: A Simple Checklist Approach for Improving Operating Room Safety

Sir: The article by Drs. Rosenfield and Chang1 was an eye opener, particularly for the young plastic surgery trainee who is in the early part of his or her career. By comparing the patient safety checklist with that of an aircraft pilot’s checklist, the authors have critically underscored the importance of safety protocols. For example, a few common errors of omission in the operating room are forgetting to remove the adhesive diathermy pads from the thigh and electrocardiography electrode stickers from the back, forgetting to remove the intravenous and subcutaneous lines on time in the postoperative period, and forgetting to check whether the patient has voided after removal of the indwelling urinary catheter. Academic and nonacademic centers worldwide have their own safety protocol checklists. The checklist in the article is definitely the most viable, and we would like to add one more point that is definitely of value. We would suggest that tourniquet application and removal time be added so that the critical ischemia time can be ascertained. These protocols, once adopted and followed regularly, will definitely become a habit over time, and errors of omission can be prevented. It was heartwarming to read that, by following the safety protocols, the error of omission has become a rare event, and we do agree with that. We once again congratulate and thank the authors for their study on safety protocols. In our opinion, with slight modifications, the checklist can be adopted as a universal safety protocol, similar to the universal standard precautions adopted in biohazard cases worldwide. Nambi Ilango, M.S. Jeeth Jacob, D.N.B. Ashish K. Gupta, M.S., M.Ch. Department of Plastic Surgery Christian Medical College Vellore, Tamilnadu, India DISCLOSURE None of the authors has a financial or other interest in any of the contents of this letter.

Critical ischemic time for the rat ovary: Experimental study evaluating early histopathologic changes

The aim of the present study was to determine a critical ischemic time for ovary in an experimental study in rats. An experimental model using slip-knot tying of all ovarian arteries and veins in cycling female rats was developed. Rat ovaries were tied using the technique through an explorative laparotomy. Complete ischemia times of 1, 2 and 3 h were used for the study. At the end of the ischemic times, the ovaries were harvested following 1 h of reperfusion. Histology indicated a gradually increased congestion correlating with the respective increased ischemic times. According to the present findings 2 h complete ischemia yields a significant injury. The model used in the present study may be used for complete ischemia-reperfusion injury of the rat ovary.

Effect of Celecoxib on Fasciocutaneous Flap Survival and Revascularization

To study the effect of celecoxib (Celebrex; Pfizer, Cambridge, Mass) on (1) primary ischemic time and (2) revascularization of fasciocutaneous free flaps in a rat model. In the ischemia study, 50 male Sprague-Dawley rats were divided into 2 groups of 25 rats each, a control group and a celecoxib group. Five rats in each treatment group were exposed to ischemic times of 4, 6, 8, 10, and 12 hours. Survival of the flap was assessed 7 days after reversal of the ischemia. Probit curves and the critical ischemic time were calculated. In the revascularization study, 30 male Sprague-Dawley rats were divided into 2 groups of 15 rats each. One group was fed celecoxib, while the other was fed a normal diet. All rats had a 3 x 6-cm fasciocutaneous flap based on the inferior epigastric artery elevated and exposed to 2 hours of primary ischemia. The flap was then sutured back into the wound bed. Each of these groups was then divided into 3 groups of 5 rats whose pedicles were divided on postoperative day 5, 6, or 7. Percentage survival of the flap was measured 7 days later. In both parts of the study, the experimental group was fed celecoxib, 1500 ppm, throughout the interoperative period. In each animal, a 3 x 6-cm ventral fasciocutaneous groin flap based on the left superficial epigastric artery was elevated. In the ischemia study, respective flap survival rates from the control and celecoxib groups at the various ischemic times were as follows: 4 hours, 100% and 100%; 6 hours, 80% and 100%; 8 hours, 80% and 80%; 10 hours, 60% and 60%; and 12 hours, 20% and 10%. The median lethal ischemic times were 9.7 and 9.6 hours, respectively. There was no statistical difference in flap survival between the celecoxib and control groups. In the revascularization study, ligation of the flap pedicle on day 5, 6, or 7 did not result in any difference in the percentage of flap survival among the 3 groups. Celecoxib appears to have no deleterious effect on free tissue transfer survival or healing, as evidenced by revascularization in a fasciocutaneous free flap model.

Critical ischemia time in a model of spinal cord section. A study performed on dogs

Vascular changes after acute spinal cord trauma are important factors that predispose quadriplegia, in most cases irreversible. Repair of the spinal blood flow helps the spinal cord recovery. The average time to arrive and perform surgery is 3 h in most cases. It is important to determine the critical ischemia time in order to offer better functional prognosis. A spinal cord section and vascular clamping of the spinal anterior artery at C5-C6 model was used to determine critical ischemia time. The objective was to establish a critical ischemia time in a model of acute spinal cord section. Four groups of dogs were used, anterior approach and vascular clamp of spinal anterior artery with 1, 2, 3, and 4 h of ischemia and posterior hemisection of spinal cord at C5-C6 was performed. Clinical evaluation was made during 12 weeks and morphological evaluation at the end of this period. We obtained a maximal neurological coordination at 23 days average. Two cases showed sequels of right upper limb paresis at 1 and 3 ischemia hours. There was nerve conduction delay of 56% at 3 h of ischemia. Morphological examination showed 25% of damaged area. The VIII and IX Rexed's laminae were the most affected. The critical ischemia time was 3 h. Dogs with 4 h did not exhibit any recovery.

Caspase Inhibition Enhances Ischemic Tolerance of Fasciocutaneous Flaps

To demonstrate the significance of apoptosis in ischemia-reperfusion injury in revascularized fasciocutaneous flaps and test the hypothesis that pharmacologic inhibition of caspases prolongs the allowable primary ischemia time of these flaps. Animal study using the epigastric flap in adult male Sprague-Dawley rats. Fifty-nine rats were treated with the caspase inhibitor (Q-VD-OPH) reconstituted in dimethylsulfoxide (DMSO) (n = 20, 8 mg/kg:0.8 mL/kg), DMSO alone (n = 19, 0.8 mL/kg), or saline (n = 20, 0.8 mL/kg). Treatment was given as a single intraperitoneal injection 30 minutes before starting primary ischemia. Epigastric flaps were subjected to increasing ischemia times followed by reperfusion. The flaps were harvested and analyzed 7 days later, and viability was assessed. Probit statistical analysis was used to determine the critical ischemia time. This was defined as the time point when 50% of the flaps in each group were expected to survive. The calculated critical ischemia times were 8.92 hours (95% confidence interval 7.19-10.47 h) for the saline group, 16.35 hours (95% confidence interval 11.82-19.89 h) for the DMSO group, and 21.73 hours (95% confidence interval 19.39-25.37 h) for the DMSO with Q-VD-OPH group. These differences were significantly different from each other. Pretreatment of fasciocutaneous flaps with a free radical scavenger alone or in combination with a caspase inhibitor significantly increases the flap's tolerance of primary ischemia. The added benefit of the caspase inhibitor suggests that apoptosis plays an important role in ischemia-reperfusion injury in soft tissue flaps.

Deep circumflex iliac cutaneous free flap in cats.

To develop and assess the survival of a microvascular cutaneous free flap based on the ventral branch of the deep circumflex iliac (DCI) artery and vein in cats. Experimental study. Phase 1: 6 feline cadavers; Phase 2: 2 adult cats; Phase 3: 10 adult cats. Phase 1: Selective angiographic study of the deep circumflex iliac artery was completed in 6 feline cadavers. After injection of the DCI artery with barium, high-detail radiographs were made of skin flaps harvested from the lateral flank and thigh region. The extent of the cutaneous angiosome was mapped with regard to the underlying anatomical landmarks. Phase 2: An island flap based on anatomic boundaries of the DCI angiosome derived from phase 1 of the study was elevated in 2 cats. Flaps were observed for 3 weeks for survival. Phase 3: Free skin flaps based on the DCI vessels were harvested in 10 cats and transferred to the dorsal interscapular region. Flaps were evaluated for 2 weeks for survival. Tissue samples were collected for histopathology, and angiograms of the flaps were completed. Phase 1: Angiograms revealed a large primary cutaneous angiosome of the DCI artery located over the lateral femoral region, which extended from the iliac crest to the level of the patella. Phase 2: All island flaps survived for 3 weeks. Phase 3: Six free flaps survived for 2 weeks, and 4 flaps failed completely. Failure of 1 flap occurred because of avulsion of the venous and arterial anastomosis postoperatively. Another cat had intraoperative hemorrhage, which resulted in anemia and hypovolemia and likely caused the flap to fail. The other 2 flaps that failed had poor perfusion intraoperatively and had the longest ischemia times. The cutaneous DCI free flap in cats may be clinically useful in reconstruction of large cutaneous wounds. The length of ischemia time for successful cutaneous free flap transfer in the cat may be shorter than in other species. Large wounds created by trauma or oncologic ablative surgery in cats could be reconstructed with cutaneous microvascular free flap. Additional studies assessing the critical ischemia time of cutaneous flaps in cats and evaluating the use of this flap clinically are needed.

Vascular Injuries of the Upper Extremity

Vascular injuries of the upper extremity represent approximately 30% to 50% of all peripheral vascular injuries. The majority of injuries are to the brachial artery, and 90% of injuries are due to penetrating trauma. Return of function is often related to concomitant injury to peripheral nerves. However, timely restoration of blood flow is essential to optimize outcome. The diagnosis is made by physical examination and limited Doppler ultrasonography. Arteriography may be helpful if there are multiple sites of injury. Anticoagulation with heparin should be given if not otherwise contraindicated. Revascularization should be completed within the critical ischemic time: 4 hours for proximate injuries and 12 hours for distal injuries. Revascularization methods include resection and primary repair or resection with an interposition graft. The sequence of repair of multiple injuries to the extremity begins with arterial revascularization followed by skeletal stabilization and nerve and tendon repair.

Vascular Injuries of the Upper Extremity

Vascular injuries of the upper extremity represent approximately 30% to 50% of all peripheral vascular injuries. The majority of injuries are to the brachial artery, and 90% of injuries are due to penetrating trauma. Return of function is often related to concomitant injury to peripheral nerves. However, timely restoration of blood flow is essential to optimize outcome. The diagnosis is made by physical examination and limited Doppler ultrasonography. Arteriography may be helpful if there are multiple sites of injury. Anticoagulation with heparin should be given if not otherwise contraindicated. Revascularization should be completed within the critical ischemic time: 4 hours for proximate injuries and 12 hours for distal injuries. Revascularization methods include resection and primary repair or resection with an interposition graft. The sequence of repair of multiple injuries to the extremity begins with arterial revascularization followed by skeletal stabilization and nerve and tendon repair.

Effect of photodynamic therapy on the critical primary ischemic time of fasciocutaneous flaps.

Photodynamic therapy (PDT) may be used as an adjuvant intraoperative therapy to improve locoregional control. PDT has been shown to delay wound healing. This raises concern about PDTs effect on survival of fasciocutaneous flaps. Evaluate the effect of 1) PDT on the critical ischemic time in a rat fasciocutaneous flap model and 2) photosensitizer activation by the surgical light source. A fasciocutaneous flap, based on the left inferior epigastric vessels, was used. Ischemic times of 2, 4, 6, 8, 10, and 12 hours were induced by clamping the vascular pedicle. Animals were randomly divided into five groups: ischemia only, group I; light treatment to wound bed, group II; Photofrin before surgery with the flap elevated without a fiber optic head light, group III, or with a headlight, group IV; Photofrin prior to surgery with light treatment to the wound bed, group V. Flap survival was assessed on postoperative day 7. The critical primary ischemic time of group V (PDT) was significantly less (P < .05) than groups I, II, III, and IV. There was no statistical difference in the critical primary ischemic time when a fiber optic headlight was used (group III vs. group IV). Intraoperative PDT significantly reduces the critical primary ischemic time of the rat fasciocutaneous flap. White light illumination of the operative field does not result in photosensitizer activation and has no effect on the critical primary ischemic time.