Intra-arterial tissue plasminogen activator: an effective adjunct following microsurgical venous thrombosis

This study evaluates the efficacy of our protocol using intra-arterial infusion of tissue plasminogen activator (TPA) on free flap salvage following venous thrombosis. A retrospective review was conducted of every free flap performed by a single surgeon since the beginning of his practice. Free flap salvage rates were documented following flap exploration, intra-arterial infusion of TPA, and revision of the venous anastomosis, with or without vein grafting. One hundred twenty-two free tissue transfers were performed from July 2003 through April 2006. Twelve anastomotic complications occurred in 11 flaps (1 arterial thrombosis, 11 venous thromboses). One free muscle flap failed due to arterial thrombosis. All venous thromboses were salvaged using the TPA protocol, although one revision thrombosed on postoperative day 1 and required a second venous revision, leading to its ultimate salvage. We believe that intra-arterial TPA is an effective adjunct in the treatment of microsurgical venous thrombosis and may increase salvage rates following anastomotic complications.     

Role of thrombolysis in free-flap salvage

Approximately 5 percent of microvascular free-tissue transfers fail; often this is due to microvascular or peri-anastomotic thrombosis. Various reports have advocated the use of thrombolytics for salvage of these flaps, although clinical evidence supporting this approach is sparse. The authors attempted to review their own and other published results and present an algorithm for the use of thrombolytics in the management of failing free flaps. A retrospective review of 590 free flaps, revealed 71 (12 percent) requiring re-exploration for impending flap failure, determined by standard clinical indicators. Forty-four (62 percent) were found to have pedicle thrombosis and 20 (28 percent) received thrombolysis with streptokinase or urokinase. All 44 flaps were grouped by final outcome and thrombolytic use for comparison. In 24 (55 percent) of the flaps with evidence of thrombosis, the use of thrombolytics was felt to be inappropriate or unnecessary; 13 (54 percent) of these were salvaged. Twenty flaps, however, did receive thrombolysis and 6 (30 percent) of these were salvaged. There was no statistically significant difference among groups with respect to preoperative risk factors, age, gender, flap type, and site of anastomotic thrombosis. There was a twofold higher use of vein grafts in the failed vs. salvaged flaps (36 percent vs. 15.7 percent), and no flaps with vessel grafts were salvaged with thrombolytics. Despite the fact that all flaps were re-explored within 3 hr of a problem being detected, the mean time from the initial operation to re-exploration was significantly higher in flaps that did not respond to thrombolytics (63. 8 vs. 32.8 hr, respectively, p=0.0457). Also, the mean time to re-exploration was significantly higher in the salvaged flaps receiving thrombolysis vs. those that did not (32.8 vs. 22.3 hr, respectively, p=0.0264). While early detection and re-exploration are crucial for salvaging failing free flaps, those flaps unresponsive to other standard interventions may benefit from the selective use of thrombolytics.     

Thrombolytic therapy: what is its role in free flap salvage?

Thrombolytic agents have been demonstrated to improve free flap salvage in animal models. However, clinical evidence regarding their efficacy has been scant. The authors reviewed their experience with flap salvage using thrombolytic therapy in 1,733 free flaps from February 1990 to July 1998. Patients with intraoperative pedicle thrombosis were excluded from this review. Forty-one of the 55 free flaps that were reexplored emergently were identified as having pedicle thrombosis. Of these 41 flaps, 28 free flaps were salvaged (flap salvage group, 68%) and 13 free flaps failed (flap failure group, 32%). Thrombolytic therapy (urokinase in 7 patients, tissue plasminogen activator in 1 patient) was used in six flaps in the flap salvage group and two flaps in the flap failure group. Statistical analysis demonstrated no difference between the two groups with regard to thrombolytic therapy. There was also no difference between the two groups with regard to use of systemic heparin (100-500 U per hour) at the time of pedicle thrombosis or with regard to whether Fogarty catheters were used. Smoking, preoperative radiotherapy, and the use of interpositional vein grafts during initial flap reconstruction had no impact on the outcome of flap salvage. The flap salvage group was reexplored at a mean of 1.5 days compared with the flap failure group, which was reexplored at a mean of 4.2 days (p = 0.007). Early detection of pedicle thrombosis remains the most important factor in the salvage of free flaps. Although these numbers are small and definitive statements cannot be made, the role of thrombolytic agents in free flap salvage requires further clinical evaluation.     

Role of recombinant tissue plasminogen activator in free flap salvage

The use of recombinant tissue plasminogen activator (rTPA) in microvascular surgery has been previously reported, but no consensus exists regarding its indications, dose, efficacy, or safety. The records of all patients undergoing free tissue transfer at one institution between 2000 and 2005 were reviewed. Patients requiring reexploration for pedicle thrombosis were identified. Chi-square and the two-sided Fisher's exact tests were used to compare differences between the two groups. Two hundred seventy-five free flaps were performed in 259 patients. In 27 cases (10 percent), reexploration for impending failure was performed, and pedicle thrombosis was observed in 22 cases. In 15 cases, rTPA was administered. Ten of these flaps (67 percent) were successfully salvaged, compared to 2/7 (29 percent) in the no-rTPA group. Heparin was used in 12 patients but was not associated with a higher salvage rate. These findings suggest that the isolated perfusion of rTPA in the salvage of the failing free flap may be more effective than anastomotic revision alone and should be considered when vascular thrombosis is encountered on reexploration of the failing free flap.     

The distally planned lateral arm flap in hand reconstruction

The lateral arm flap is a versatile free flap with straightforward dissection and low donor site morbidity. However, it presents some drawbacks: the vascular pedicle is relatively short (2-6 cm), and the flap is rather thick. Further surgery is often needed to decrease flap volume. An anastomotic network between the posterior collateral radial artery and the recurrent radial artery allows the skin paddle to be safety located over the epicondylar region and proximal forearm. This modification increases pedicle length up to 100% and limits the amount of subcutaneous fat. A series of eight consecutive distally planned lateral arm flaps used for hand reconstruction is presented. The medical records and operative notes were reviewed. Six patients were reviewed. The minimum follow-up was six months. Flap size ranged from 11 x 5.5 cm to 23 x 7 cm (average 15 x 6 cm), pedicle length ranged from 8 to 10 cm (average 9 cm), no venous grafts were needed for the microanastomosis. The mean flap harvesting time was 50 minutes. All donor sites were closed primarily. All flaps survived totally despite postoperative arterial thrombosis in one case that was salvaged by a skin graft over the surviving fascia. To date, no further surgery was needed to debulk the flaps. The donor site scar was enlarged in one patient. Elbow mobility was unaffected by surgery. Patient self-assessment of appearance of both reconstruction and donor site showed a high satisfaction rate. The distally planned lateral arm flap presents decreased bulk and a longer pedicle than the classical lateral arm flap with no added technical difficulties.     

Vascular complications of vascularized composite tissue transfer: Outcome and salvage techniques

Two hundred fifty-two vascularized composite tissue transfers were performed from 1985 to 1992 at Nara Medical University Hospital. Free tissue transfers were performed in 185 patients and island tissue transfers in 67 patients. Of these, 39 flaps were reexplored because of vascular complications. On initial reexploration, vascular obstruction was found at the site of anastomosis or in the main vascular pedicle in 36 patients and in the perforating vessels to the monitor flap in three patients. Arterial thrombus occurred in 11 patients, venous thrombosis in 12, and both in nine. Twenty-five reexplored flaps were salvaged. Initially, heparin was administered systemically when vascular compromise was suspected intraoperatively or postopera-tively. Recently, we have used a ?continuous local heparinization”? technique to minimize blood loss. This method has been used in 12 patients who underwent reexploration and in nine patients in whom vascular compromise was suspected. Nineteen flaps survived completely, and two flaps failed. © 1993 Wiley-Liss Inc.     

Flap monitoring after head and neck reconstruction: evaluating an observation protocol

This study evaluated the postoperative free-flap monitoring frequency protocol used in a maxillofacial unit for patients receiving free-tissue transfer for reconstruction following orofacial cancer. All free-tissue transfers undertaken in the unit between January 1992 and October 1998 were reviewed retrospectively. Of the 370 patients evaluated, 46 returned to theatre with compromised free flaps. The compromise was purely venous in origin in 37 of these cases, arterial in three and due to a combination of arterial and venous problems in six. Thirty-five of the flaps were successfully salvaged. On average, the clinical manifestation of the problem occurred 25.5 hours postoperatively. However, there was a significant time difference between flaps that were salvaged successfully and those that were not: in the salvaged group the compromise was identified 17.5 hours postsurgery compared with 51 hours for the unsuccessful group. The timing of the return to theatre following the identification of the compromise was a significant factor in the success rate: 71 minutes for those salvaged and 103 minutes for those not salvaged. It is recommended that flaps are monitored hourly for the first 72 postoperative hours and observations recorded on a chart.     

Temporary arteriovenous shunt prior to free flap transfer

The establishment of a temporary arteriovenous shunt (TAVS) near a recipient site with inadequate local vessels may facilitate the subsequent re-vascularization of a free flap. In nine patients a TAVS was constructed prior to the transfer of free flaps. The indication was either the absence of vessels or inadequate recipient vessels. In eight of the nine patients the establishment of the shunt proved successful. In one patient a re-creation of the shunt was necessary owing to thrombosis caused by infection. In another patient the shunt thrombosed and no further microvascular surgery was possible. The construction of a TAVS increases the possibility of more extensive application of free flap transfer. Should the creation of the shunt prove futile, the donor flap may still be salvaged for further application. A staged transfer of a free flap after the primary establishment of a TAVS gives the best changes for adequate vascularization of the flap and reduces the risk of thrombosis.     

Infrared surface temperature monitoring in the postoperative management of free tissue transfers

BACKGROUND:

Early identification of failing free flaps may allow for potential intervention and flap salvage. The predictive ability of flap temperature monitoring has been previously questioned. The present study investigated the ability of an infrared surface temperature monitoring device to detect trends in flap temperature and correlation with anastomotic thrombosis and flap failure.

METHODS:

Postoperative measurement of surface temperature was obtained in 47 microvascular free flaps. Differences in temperature between survival and failure groups were evaluated for statistical significance using Student’s t test (P<0.05). In addition, a single variable analysis was performed on 30 different flap characteristics to evaluate their prediction of flap failure.

RESULTS:

In total, eight flaps failed. Five of these were re-explored, of which one was salvaged. The three other flaps died a progressive death secondary to presumed thrombosis of the microcirculation despite adequate Doppler signals. Temperatures of the flap failure group during the last 24 h yielded a mean difference of 2°C (3.56°F) compared with surviving flaps (P<0.05). The temperature of the failing flaps began to decline at the eighth postoperative hour. Single variable analysis identified prior radiation to be a predictor of flap failure.

CONCLUSIONS:

A surface temperature measurement device provides reproducible digital readings without physical contact with the flap. Technical difficulties encountered in previous research with implantable or surface contact temperature probes are obviated with this noncontact technique. Flap temperature monitoring revealed a trend in temperature that correlates with anastomotic thrombosis and eventual flap failure.     

Is the preoperative MPV value related to early thrombus formation in microvascular anastomosis?

Objective: One of the most common encountered problems in free flap surgeries is anastomotic thrombosis. The mean platelet volume (MPV) may indicate the concentration of intra-platelet proactive substances and the thrombogenic potential of the platelets. MPV is used as a clinical monitoring index in routine blood counts, it has not yet been effectively used in free flap surgery.

Methods: This study evaluates the relationship between the preoperative MPV value and anastomotic thrombus formation during the postoperative 48?hours in 32 free flap operations from September 2013 to September 2014. The mean patient age was 36.75 years. The preoperative MPV value, which was obtained from the complete blood count, was recorded and correlation of MPV and postoperative thrombus formation was investigated.

Results: Four anastomotic thrombus were encountered in 34 free flaps during the postoperative 48?hours. Two of them were salvaged by performing thrombectomy and/or administration of i.v. heparin. There was no statistical relationship between MPV value and postoperative thrombus formation during 48?hours follow-up (p?=?0.925).

Conclusion: Even though this study didn’t find a correlation between preoperative MPV value and postoperative early anastomotic thrombus, it would be helpful to validate the results using multi-centre and comprehensive studies with larger patient cohorts.     

The intrinsic transit time of free microvascular flaps: Clinical and prognostic implications

Background: Microscope‐integrated indocyanine green near‐infrared videoangiography (ICGA) is a new method for the intraoperative assessment of vascular flow through microvascular anastomoses. The intrinsic transit time (ITT) describes the time period from the dye appears at the arterial anastomosis (t₁) till it reaches the suture line of the venous anastomosis (t₂). As the transit time reflects blood flow velocity within the flap, prolonged ITT might correlate with low blood flow and a higher rate of postoperative thrombosis. We performed a clinical trial evaluating the association between intraoperative free flap transit time and early anastomotic complications in elective microsurgery. Methods: One hundred consecutive patients undergoing elective microsurgical procedures underwent intraoperative ICG angiography (ICGA). In patients with anastomotic patency, angiograms were retrospectively reviewed and the intrinsic transit time was calculated. Postoperative outcome was registered and compared with the ITT. End points included early reexploration surgery and flap loss within the first 24 hours after surgery. Results: Fourteen patients were excluded from the study due to technical anastomotic failure. The overall flap failure rate was 6% (5/86); the incidence of early re‐exploration surgery was 10% (9/86). With a median of 31 seconds patients with an uneventful postoperative course showed significantly shorter ITTs than patients with flap loss or early postoperative reexploration (median: >120 seconds). An optimal cut‐off value of ITT > 50 seconds was determined to be strongestly associated with a significantly increased risk of at least one positive end point. Conclusions: This study demonstrates a significant predictive value of the intrinsic flap transit time for the development of flap compromise and early re‐exploration surgery. © 2009 Wiley‐Liss, Inc. Microsurgery, 2010.     

Outcomes of flap salvage with medicinal leech therapy

Medicinal leech therapy (MLT) to salvage venous congestion in native skin and local flaps is commonly practiced. However, the role of MLT in compromised regional and free flaps remains unclear. Leeches were used in 39 patients to treat venous congestion in native skin (n = 5), local flaps (n = 6), regional flaps (n = 14), and free flaps (n = 14). There were no total losses in patients with compromised native skin or local flaps. One patient who had received a radial forearm free flap expired before flap outcome could be assessed, and was excluded from analysis. Of the remaining 27 regional and free flaps, 33.3% were salvaged, 33.3% were partially salvaged, and 33.3% were lost. Means of 38.3 ± 34.0, 101.0 ± 11.2, and 157.9 ± 224.4 leeches and 1.7 ± 3.6, 3.2 ± 4.4, and 5.6 ± 5.2 units of blood were required for the salvaged, partially salvaged, and lost groups, respectively. Twenty-two patients required blood transfusion (57.9%). No patients developed wound infection with Aeromonas hydrophilia. Two patients developed donor site hematomas, and four patients developed recipient site hematomas. MLT is efficacious in congested native skin and local flaps. Some regional and free flaps can be totally or partially salvaged. However, the morbidity of MLT must be weighed against the risks of flap loss.     

Successful venous thrombectomy in complicated microsurgical head and neck reconstruction: report of two cases

Even with excellent results in microsurgical free flap surgery, the reported overall complication rates still range from 17.2% to 52.8%. Among these complications, venous thrombosis has been recognized as one of the most severe. This condition can be treated by various surgical and non-surgical methods. Two cases of a fibula osseofasciocutaneous free flap reconstruction for head and neck cancer complicated by venous thrombosis at anastomotic sites are reported. This was successfully salvaged by Fogarty venous catheter thrombectomy followed by re-anastomosis.     

The role of microvascular free flaps in salvaging below-knee amputation stumps: a review of 22 cases

Twenty-two cases of traumatic below-knee amputation stumps with inadequate soft-tissue coverage salvaged with microvascular free flaps were reviewed retrospectively. All patients would have required an above-knee amputation for prosthesis fitting had microvascular free flaps not bee utilized. A total of 24 flaps were used in 22 patients; parascapular 11 (46%), foot filet six (25%), latissimus dorsi four (17%), lateral thigh, tensor fascia lata, and groin one (4%). Free flaps were performed immediately after injury in five (21%) cases, within the first week in two (8%), between 1 and 3 months in 12 (50%), and after 3 months in five (21%). Fifty per cent of the patients had significant other injuries. The patients had a total of 107 operations (mean, 4.9) related to their injury: 33 (mean, 1.5) of those operations were after the free flap, 27 (25%) of which were either performed because of a complication of the free flap or for revision of the free flap. Complications included partial necrosis in five (21%), neuroma in three (13%), hematoma in two (8%), donor site complication in two (8%), thrombosis requiring reoperation in one (4%), and flap failure in one (4%). Patient followup ranged from 12 to 116 months. All patients maintained a functional below-knee prosthetic level. The mean time to ambulation was 5.75 months, and was not significantly affected by flap complications. Most patients employed before their injury were employed after their injury. Despite a protracted course in these severe injured trauma patients, a functional below-knee amputation level was preserved in all cases utilizing microvascular free flaps.     

Early reintervention of compromised free flaps improves success rate

INTRODUCTION AND AIM: To develop a protocolized monitor schedule in microvascular free flap reconstruction, we investigated a possible correlation between the outcome and the interval between clamp release and start of revision. MATERIALS AND METHODS: All the charts of patients treated between 2000 and 2006 with a free flap were evaluated. The patients who underwent a flap revision were further analyzed. RESULTS: A total of 608 free flaps were evaluated; 69 of these flaps were revised. Most vascular complications took place within the first 24 h; the latest complication was observed 8 days after surgery. After 6 days post surgery, the number of revisions decreased considerably. With regard to the salvaged flaps the mean time to start the revision was 46.5 h (SD 39). With regard to the failed revisions, the mean time to start the revision was 82.0 h (SD 47). This difference proved significant (P = 0.006). CONCLUSION: Our data shows that the majority of anastomotic failures occur within the first 24 h. Thereafter, the frequency of failures decreases. We also found that the time between initial reconstruction and start of the salvage procedure influences the outcome of the revision negatively.     

Microvascular breast reconstruction pedicle thrombosis: How long can we wait?

Re-exploration plays a key role in salvaging vascularly compromised free flaps. A retrospective review of 290 free flaps in breast reconstruction was performed to determine whether the time delay between thrombosis detection and surgical re-exploration had any effect on flap salvage. Overall flap success was 97.6%. Postoperative thrombosis requiring re-exploration was documented in 6.2% cases. Fifty-five percent of take-back flaps were salvaged and 45% were lost. The median time between detection of flap compromise to surgical incision was 128 min in our saved flaps, and 228 min in the lost flap group. Our preliminary data suggests that re-exploration within 188 min may improve flap salvage.     

Cold ischemia in microvascular breast reconstruction

Introduction: A major drawback to microvascular free flap breast reconstruction is the length of operation—up to 9 hours or more for bilateral reconstruction. This takes a significant mental and physical toll on the surgical team, producing fatigue that may compromise surgical outcome. To facilitate the operation we have incorporated a period of cold ischemia of the flaps such that members of the surgical team can alternate a brief respite during the operation. Methods: We retrospectively reviewed our series of microvascular free flap breast reconstructions performed over a four‐year period in which cold ischemia of the flaps were induced. Results: Seventy patients underwent free flap breast reconstruction with 104 flaps. Mean cold ischemia time for all flaps was 2 hours 36 min. Average rest time per surgeon per case was 35 min. Complications included two total flap losses (1.9%), one partial flap loss (1.0%), one anastomotic thrombosis (1.0%), two hematomas (1.9%), three fat necrosis (2.9%), and two delayed healing (1.9%). Statistical analysis revealed that the probability of complications is inversely related to cold ischemia time (P = 0.0163). Conclusion: Cold ischemia facilitates breast reconstruction by allowing the surgical team to alternate breaks during the operation. This helps reduce surgeon fatigue and is well tolerated by the flap. Thus, we believe that the use of cold ischemia is safe and advantageous in microvascular breast reconstruction. © 2010 Wiley‐Liss, Inc. Microsurgery 30:361–367, 2010.     

Thromboprophylaxis in microsurgery

Microsurgical free tissue transfer has become a gold standard in a wide range of clinical situations. Thrombosis at the anastomotic site is not only the most common cause of failure of microsurgical operations, but it is also one of the factors resulting in microcirculatory intravascular thrombosis in free flaps. All conditions of thrombus formation, defined by Virchow in 1856, are encountered in free flap surgery. This literature review concerns the problem of thromboprophylaxis in microsurgery. All citations published this last ten years (1996-2005) concerning this problem are noted. Data are confronted with other specialties, particularly vascular surgery, or with large retrospective studies. Protocol used in our institution is presented at the end of this lecture.     

游离腹壁浅动脉筋膜穿支皮瓣修复手部创面

目的 报告应用游离腹壁浅动脉筋膜穿支皮瓣修复手部创面的临床效果.方法 对10例手部皮肤软组织缺损的患者,采用游离腹壁浅动脉筋膜穿支皮瓣进行修复,皮瓣切取面积为8cm×6cm～16cm×9cm.结果 术后1例皮瓣发生血管危象,经探查后存活,其余皮瓣全部顺利存活.经4～12个月的随访,皮瓣质地、外形优良,手功能恢复满意.术后供区伤口均Ⅰ期愈合,外形满意.结论 应用游离腹壁浅动脉筋膜穿支皮瓣可以一期修复创面,供区损伤小,是修复手部创面的理想选择.     

Tissue pH monitoring in microsurgery: a preliminary evaluation of continuous tissue pH monitoring as an indicator of perfusion disturbances in microvascular free flaps

In an experiment using a continuous tissue pH monitoring system, selective occlusion of the vessels supplying lower abdominal island flaps in Sprague-Dawley rats resulted in predictable tissue pH changes. Arterial occlusion resulted in a rapid fall in pH. In all three experimental groups, the steepest rate of pH drop occurred during the first 30 minutes postocclusion. In a series of 9 patients who underwent microvascular free flap surgery the continuous pH monitor was employed postoperatively. Tissue pH was (and remained) normal in well-perfused free flaps. Tissue pH fell almost immediately with anastomotic failures. These findings demonstrate that pH measurement offers the microvascular surgeon a new, simple, and reliable approach to perfusion assessment in free flaps. Perhaps improved survival rates will result from earlier anastomotic exploration in compromised free flaps that exhibit falling pH values.