Free flap surgery: the Welsh Regional Unit experience

The evolution and uses of free tissue transfer since 1976 are documented. Two hundred free flaps have been performed with an overall success rate of 91%. The factors which may influence survival are the type of flap used, the recipient region and the timing of surgery following trauma. Twenty-five percent of cases required re-exploration postoperatively, of which 78% were successfully salvaged. Venous thrombosis was the commonest problem and appears better tolerated than arterial occlusion. Eighty-two percent of venous thromboses were salvaged compared with only 50% of arterial failures.     

Internal jugular vein versus external jugular vein anastamosis: implications for successful free tissue transfer

BACKGROUND: Microvascular free flaps are becoming the reconstructive option of choice for many head and neck defects. Many previous studies have examined factors predicting free flap survival. No study has compared differences in free flap survival when anastomosed to the internal or external jugular systems. METHODS: Retrospective review of all free flaps performed at an academic medical center by a single head and neck microvascular surgeon during the period July 1995 to December 1999. Flaps were closely monitored postoperatively and taken back to the operating room urgently for arterial insufficiency or venous congestion. RESULTS: On hundred fifty-six free flaps were performed during this time period. Sixty-five free flaps were anastomosed to the external jugular (EJ) vein and 86 to the IJ system (62 to the proximal common facial vein, 17 end-side on the IJ, and 7 to other branches). Five had either two venous anastomoses or were anastomosed to other veins and were excluded from statistical analysis. Six (4%) vascular thromboses occurred; 5 were venous and 1 arterial. Success by group was 99% for IJ anastomosis (1 arterial thrombosis) and 92% for EJ anastomosis (5 venous thromboses, p =.03). Urgent anastomotic revision and reperfusion salvaged 5 of the 6 flaps (overall success 99%). CONCLUSIONS: Although the overall success rate (96% success with 99% success with salvage) is comparable to other large series, microvascular free flaps anastomosed to the external jugular vein failed at a significantly higher rate than those anastomosed to the IJ system. This suggests that the IJ system should be used as a recipient vessel when feasible.     

Arterialized venous perfusion of composite tissue

The results of our experiment prove that arterialized venous perfusion is a viable means of nourishing complex composite tissue without using the arterial tree. Previous laboratory findings, coupled with the results of this experiment, demonstrate that as long as proximal arterial inflow is ensured, both the arterial and venous trees need not be intact to keep tissue alive. Rather, it seems that the prerequisites for tissue survival are that at least one of the two systems be intact and that there be sufficient inflow and outflow channels available. Whether these channels are arteries or veins is probably not important. The use of properly placed efferent or afferent arteriovenous fistulas allows one system to provide both physiologic functions. Whether the efferent arterial anastomosis stays open over the long term appears to be inconsequential. Survival is ensured by either direct perfusion with oxygen delivery through the venous tree or through the eventual ingrowth of recipient vessels into the flap by way of the delay phenomena. This perfusion technique is ideally suited for tissue with an inadequate arterial tree but with an intact venous system devoid of venous valves (most veins less than 1.5 mm in diameter). A well-vascularized recipient bed capable of providing vessel ingrowth into transferred tissue may be important in the case of delayed arteriovenous fistula occlusion secondary to intimal hyperplasia; therefore, further experimental study of these flaps must be undertaken before arterialized venous flaps can be recommended for placement in recipient sites compromised due to radiation, ischemia, diabetes, or other causes of small vessel disease in the recipient bed. Although efferent arteriovenous fistulas are currently used to provide arterialized venous perfusion in selected cases of end stage arterial occlusive and vasospastic disease, perhaps their greatest role is in the management of tissue transfer with an inadequate arterial tree. Much knowledge must be gained to understand the physiologic principles and requirements for optimal perfusion. Many questions are left unanswered. For example, in those arteriovenous fistulas that narrow or occlude secondary to neointimal hyperplasia or other causes, which channels (veins or arteries?) are used for perfusion during recipient vessel growth? Can intimal hyperplasia be reversed or prevented by drug therapy and would this be advantageous? Can venous valves be made incompetent so that this technique can be used for larger vessels?(ABSTRACT TRUNCATED AT 400 WORDS)     

Microvascular free tissue transfer in reconstruction of the lower limb.

Reconstruction of the lower extremity using microvascular free tissue transfer has been adopted as a routine procedure since the 1980s. Success rates in overall free tissue transfer are now as high as 98%. In the lower limb, however, the failure rate has been reported to be as high as 15 to 20%. A review of 50 consecutive microvascular free flaps to the lower extremity was carried out in the Ulster Hospital Belfast. The indication for surgery, the flap type, the recipient vessel, re-exploration rate, complication rate, success rate and the changing pattern in management during the first six years of a single consultant's practice was assessed. Six patients (12%) were re-explored for anastomotic complications or haematoma. Thrombosis of the arterial anastomosis was noted in one case, venous thrombosis in two and haematoma under the flap in the remaining three cases. Salvage was successful in four cases, thus producing an overall success rate of 96%.     

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.     

Sixty-five clinical cases of free tissue transfer using long arteriovenous fistulas or vein grafts

Traumatic limb injuries requiring free tissue transfer for coverage, often lack healthy recipient vessels adjacent to the defect. In these patients, vein grafts are required to bridge the gap of either the artery, vein or both. For the latter situation, a temporary arteriovenous fistula (AVF) can be created and allowed to mature and then divided and used as recipient artery and veins for the free flap. These cases are challenging and several variables including vein graft length, vein graft diameter, and arterial inflow affect the patency of the vessels and the final outcome of the reconstruction. Sixty-five defects were reconstructed with free tissue transfers using vein grafts of significant length (>20 cm for the arterial gap). The ipsilateral or contralateral great saphenous veins were used for vessel lengthening in all cases. Inflow arteries were either major arteries (superficial femoral, popliteal or brachial), or lesser arteries (sural, anterior or posterior tibial, thoracodorsal, or superior gluteal). The patients were divided into those that underwent AVF followed by free tissue transfer in two stages (n = 6), AVF followed by free tissue transfer in one stage (n = 28) and patients that underwent vein grafting for the arterial defect only with (n = 6) or without (n = 25) a simultaneous bypass graft for lower limb revascularization. In the two-stage AVF group, the rate of occlusion of the graft after AVF creation was 50% (3/6); re-exploration rate was 33.3% (2/6); free flap failure rate was 33.3% (2/6); and limb salvage rate was 83.3% (5/6). In the one-stage AVF group: re-exploration rate was 28.6% (8/28); free flap success rate was 89.3% (25/28); and limb salvage rate was 92.9% (26/28). In the long vein graft group for arterial defects only: re-exploration rate was 25.8% (8/31); free flap success rate was 96.8% (30/31); and limb salvage rate was 87.1% (27/31). In patients where the graft was anastomosed to a major artery the re-exploration rate and free flap failure rate were 22.4% (11/49) and 8.2% (4/49). In patients where the graft was anastomosed to a lesser artery, the re-exploration rate and free flap failure rate were 43.4% (7/16) and 12.5% (2/16). The limb salvage rate was comparable in both groups (89.8%, 44/49, versus 87.5%, 14/16). In all groups, patients undergoing re-exploration were noted to have a an arterial gap of 31.78 cm as compared with the patients that did not require re-exploration which had an arterial gap of 26.26 cm. Vein grafting for bridging vascular defects is a safe procedure when proper indications and techniques are followed. Although a longer graft length seemed to be associated with a higher re-exploration rate, there was no statistical significance. One-stage AVFs can be used with good results, however, two-stage AVFs are associated with a high graft occlusion rate, wound failure rate and limb amputation rate. In all cases, a large caliber graft such as the great saphenous vein provided a large (relatively low resistance) conduit for bridging the defect.     

Continuous postoperative monitoring of cutaneous free flaps using near infrared spectroscopy.

Reliable detection of circulatory compromise threatening free-flap viability is essential for prompt surgical intervention and flap salvage. Numerous techniques have been developed to address the issue of postoperative flap monitoring but none have achieved universal acceptance. Near infrared spectroscopy (NIRS) is a noninvasive technique that allows continuous monitoring of tissue oxygenation and perfusion. It is increasingly recognised to be a reliable method for flap viability assessment. This study was designed to investigate the ability of NIRS to detect and identify microvascular thrombosis endangering flap survival. To our knowledge, this is the first clinical evaluation of NIRS used for continuous monitoring of free flaps. METHODS: Fifty flaps used for autologous breast reconstruction in 48 patients were included in this prospective clinical study. NIRS was employed for 72-h continuous postoperative monitoring. The data were compared to findings of clinical assessments. RESULTS: Ten flaps (20%) developed 13 anastomosis thromboses (two arterial and 11 venous). NIRS detected all cases of flow failure prior to clinical observation with no false positives or negatives. Based on consistent patterns of NIRS parameter changes, it was possible to differentiate between changes caused by arterial and venous thrombosis with accuracy before surgical re-exploration. The salvage rate was 70%. Overall flap viability was 94%. CONCLUSIONS: Continuous NIRS monitoring can reliably detect and identify early stages of arterial and venous thrombosis, and is a credible method for noninvasive postoperative flap surveillance. Based on these findings, we advocate its use for monitoring of flaps with a cutaneous component.     

Free flap transfer bridged by antegrade and retrograde posterior tibial vessel flaps temporally borrowed from the healthy leg

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Venous flaps in digital revascularization and replantation

This is a report on 15 patients who underwent replantation/revascularization of a single digit with a substantial dorsal soft tissue defect. The dorsal defect was covered with a venous flap, a free flap that has only venous inflow and outflow. Postoperatively, the venous flaps were warm, pink, and appeared to exhibit a blanch and refill phenomenon, clinically resembling capillary filling. The flaps from the dorsal aspect of an uninjured digit had a survival rate of 100 percent, with no partial necrosis, while the flaps from a forearm or dorsal foot donor site failed. The advantages of using venous free flaps are twofold. Not only does this technique provide for venous drainage, but it also provides flap coverage and avoids complications, such as vessel occlusion or hematoma formation, associated with skin grafting over a venous anastomosis, with subsequent loss of the skin graft.     

Experimental studies of skin flaps with subcutaneous veins

The authors have previously reported that skin flaps with subcutaneous veins nourished by arterial or venous inflow survived, despite being sited on recipient beds with poor circulation. In these previous studies, experimental models were based on axial pattern flaps of rabbit ears. However, for clinical application, there are problems in the use of axial pattern flaps with central vessels. This report classifies skin flaps with subcutaneous veins and produces experimental models that are suitable for clinical application and investigation of survival rates. Thirty-seven rabbits (74 ears) were used in this study. A 3.0-cm x 4.5-cm skin flap with only a "passing" vein (one that traveled through the tissue without major branches to that tissue) was raised at the level of the perichondrium on the dorsum of the auricular cartilage. The flaps were divided into three groups: Group A--composite flaps (n = 10); Group B--totally venous perfused flaps (n = 30); and Group C--afferent arterialized venous perfused flaps (n = 34). More than 80 percent of the flaps became necrotic in Group A. In Group B, 18 of 20 survived with partial superficial necrosis and two became more necrotic. In Group C, 18 of 21 flaps survived with superficial necrosis and three became more necrotic. Microangiographically, as concerns the "passing" veins in Groups B and C flaps, all of the flaps survived with only superficial necrosis. The skin flaps with subcutaneous veins survived as total venous perfusion flaps (TVPF) and as arterialized afferent venous perfusion flaps (AAVPF) even though the artery was not included in the flap. The experimental model is suitable for the investigation of the clinically unconventional flap.     

Bedside monitoring of free flaps using ICG-fluorescence angiography significantly improves detection of postoperative perfusion impairment##

After microvascular tissue transfer, free flaps require meticulous postoperative surveillance. The purpose of this study was to evaluate the effect and applicability of indocyanine green fluorescence angiography (ICG-FA) in bedside monitoring of free flaps postoperatively, especially considering its role in correctly identifying vascular thromboses. Between February 2012 and October 2015, 210 free flaps used for defect reconstruction were analyzed. The flaps were monitored bedside for flap perfusion compromise by clinical examination and by ICG-FA in a standardized procedure in the first 3 postoperative days. Data were evaluated retrospectively with respect to the etiology of the perfusion compromise with special focus on vascular thromboses and revision rates. In total, 23 vascular thromboses were identified. The combination of clinical examination and ICG-FA (85%) was most successful in determining the prevalence of vascular thromboses. In 41 cases, clinical and/or ICG-FA examinations indicated revision surgery. The flap salvage rate after revision was 77% (31 cases), which results in an overall flap survival rate of 96%. The revision rates were reduced over the study time from 22% in 2012 to 12% in 2015. ICG-FA as an adjunct to clinical examination of free flaps can help in correctly identifying vascular thromboses and can help decide if revision surgery is necessary in not obvious cases of perfusion compromise.     

Microvascular histopathology in head and neck oncology.

A histological study of both recipient and flap vessels was performed in 30 patients with head and neck cancer, and relevant preoperative risk factors were assessed. A total of 35 free flaps were transferred in 30 patients; 16 patients had preoperative radiotherapy, 13 were smokers, eight had hypertension and six had peripheral vascular disease. No significant venous pathology was found in either the flap or the neck veins. However, over two-thirds of the neck arteries and one-half of the flap arteries were found to have microscopic arterial pathology. The only pre-existing factor significantly influencing vessel pathology was hypertension (P=0.007). All flaps survived, although in two there was some loss of the skin paddle. This study reveals that the majority of patients undergoing microsurgery in the head and neck region have pre-existing arterial damage in both the flap and the recipient arteries, but this does not have a significant effect on the overall patency of the microvascular anastomoses.     

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.     

Use of single saphenous interposition vein graft for primary arterial circuit and secondary recipient site in head and neck reconstruction: a case report

BACKGROUND: Autologous vein grafts are a valuable tool in microsurgical free tissue transfer. Interposition vein grafts offer the surgeon greater freedom when placing the free flap and choosing the recipient vessels, providing valuable options in case recipient vessels are not available for those patients with large wounds. Free flaps transferred to head and neck regions carry a higher risk of failure, which may be expected to increase more with the use of vein grafts. METHODS: We present our case with the double use of a single vein graft for both primary arterial conduit in end-to-end fashion and secondary end-to-side recipient site in the microsurgical reconstruction of a complicated head and neck defect. RESULTS: All these anastomoses and flaps survived perfectly, and the patient was discharged 14 days after the transfer of the second flap. CONCLUSION: Although the anastomosis of 2 flaps to a single vein graft was successful in our case, it represents a higher risk option than different recipient vessels. We provide this alternative procedure in selected patients, as there is no other receipt vessel or recipient blood flow strong enough to supply more than 1 flap.     

Use of liposuction for secondary revision of irradiated and nonirradiated free flaps

A number of patients with free tissue transfer require secondary revision to improve contour and regional definition to maximize function or appearance. However, there is controversy with regard to whether irradiated free flaps can be revised safely using liposuction. The purpose of this study was to compare the outcomes of revisionary procedures requiring liposuction in irradiated versus nonirradiated flaps. From December 1992 to July 2001, office and hospital records were reviewed retrospectively to identify patients who had undergone free tissue transfer and subsequent flap revision at a single institution. The number of revisions, amount of fat aspirated, timing of revision and the postoperative complications including infection, hematoma, wound dehiscence, and flap loss were reviewed. A total of 41 flap revisions using liposuction alone or with direct excision were performed on 33 free flaps (31 head and neck, 1 chest wall, and 1 extremity). The rectus musculocutaneous flap was the most commonly revised (88%). The average length of time to secondary revision of patients who had received postoperative radiotherapy to their flaps was significantly higher that those whose flaps had not been irradiated (P < 0.05). There were no postoperative complications except for 1 partial (20%) flap loss in a patient whose flap was irradiated. The difference in complication rates between the irradiated and nonirradiated group was not statistically significant. Secondary free flap revision using liposuction and direct excision is a safe technique for recontouring free flaps. There was no significant difference in complication rates for irradiated and nonirradiated flaps. Postoperative radiation therapy is therefore not a contraindication to secondary revision. However, these procedures should be delayed for several months after the acute effects of radiation have resolved.     

Variations in flap blood flow and tissue PO2: a new technique for monitoring flap viability

An implantable and disposable tissue oxygen tension (PO2) probe, useful as a clinical monitor following free-tissue transfer, is described. Experimentally, using the rabbit epigastric groin flap model, we have found it to be a sensitive indicator of arterial and venous occlusion. Oxygen can be given to verify the integrity of the monitoring technique and check any abnormal reading. Animals administered oxygen will have a rapid increase in tissue PO2 when the pedicle is intact. If compromised by arterial or venous occlusion, the low readings demonstrate no change. The application of this new technique for monitoring free flaps in 12 patients is presented. In 2 patients the tissue PO2 monitor successfully detected early vessel thrombosis, resulting in reexploration of the anastomoses and salvage of the free flaps.     

Arterialized venous free flaps for soft-tissue reconstruction of digits: a 40-case series

When there is not sufficient local tissue available for reconstruction of one or multiple digital defects, distant flap reconstructions are required. Available thin flaps with defined arterial inflow and venous outflow are limited and require the sacrifice of an arterial pedicle. In addition, a functional limitation can occur at the donor site. During the last decades, experimental and clinical attempts have been made in using venous flaps, based just on the venous network for in- and outflow. A 40-case series of arterialized venous free flaps in soft-tissue reconstruction of the digits and hand is presented. Neovessel formation induced by an intact venous plexus within the flap proved clinically to be the survival mechanism. Postoperative congestion was present in all flaps and subsided within 14 days; 92 percent of all flaps eventually survived. In 57.5 percent of cases, total flap survival was observed; in 17.5 percent of flaps, a superficial epidermolysis occurred, not requiring further surgery; in 17.5 percent of flaps, a full-thickness skin necrosis developed, requiring grafting (minor complication); in 7.5 percent of reconstructions, total flap necrosis was observed. Thus, in the authors' experience, when conventional local flaps are not available, arterialized venous free flaps proved to be a successful solution for soft-tissue reconstruction in digits and hands. The authors present the main indications and advantages of arterialized venous free flaps, emphasizing the essential technical steps and the most frequent pitfalls in treatment.     

游离皮瓣修复下肢缺损时受区血管的选择

目的探讨游离皮瓣修复下肢缺损时受区血管的选择。方法采用游离皮瓣移植修复下肢缺损共29例,其中膝部创面3例,小腿10例,足、踝部15例,膝下至足背严重撕脱1例;背阔肌瓣移植16例,股前外侧瓣8例,肩胛皮瓣4例,腹直肌瓣1例。用作受区的血管有旋股外侧血管(2例)、膝降血管(1例)、胫前血管(11例)、胫后血管(10例)、腓血管(2例)、足背血管(1例)和腓肠肌内、外侧血管(各1例)。结果术后3例发生血管危象,行血管探查后,2例解除危象、移植组织成活,1例失败。23例患者平均随访13(6~24)个月,下肢均恢复行走功能,除3例皮瓣外形臃肿影响穿鞋而二期行皮瓣修薄术外,其余皮瓣外形基本满意。结论下肢受区血管选择对皮瓣游离移植成功修复相当重要,必要时伤肢腓肠肌内、外侧血管或旋股外侧血管、膝降血管可作受区吻合血管。     

Dorsalis pedis arterialized venous flap for hand and foot reconstruction

Objective:To report the results of repair of skin defects in the extremities with arterialized venous flap harvested from the lateral aspect of the dorsum of the foot.Methods:Six cases of skin and soft...     

Autonomization of free flaps in the oral cavity: A prospective clinical study

Controversy exists over how long a free flap is dependent on its pedicle and if neovascularization is different between flap types, recipient sites, and irradiated and nonirradiated patients. An understanding of the timing of this process should optimize the safety of secondary procedures involving the flap. In a prospective clinical study, hemoglobin oxygenation and capillary flow were measured in 50 flaps (25 forearm flaps, 15 osteocutaneous fibula flaps, and 10 anterolateral thigh flaps) 4 and 12 weeks postoperatively. The flaps were located at the floor of the mouth, cheek, or tongue (n = 39) or at the hard or soft palate (n = 11). Measurements were carried out using the O2C monitoring system under temporary digital occlusion of the pedicle. After 4 weeks, 17 free flaps were found to be autonomized indicated by the O2C measurements comparing both values before and after digital compression of the vascular pedicle. After 12 weeks, 41 patients had completion of free flap autonomization, as indicated by the HbO(2) and CF before and after pedicle compression. The location of free flap in the lower jaw (P < 0.0001 after 4 weeks, P = 0.013 after 12 weeks), fasciocutaneous radial forearm flaps after 4 weeks (P < 0.0001), and not irradiated recipient site after 4 weeks (P = 0.014) were found to be positive factors significantly influencing autonomization. In conclusion, free flap autonomization depends on several variables which should be considered before further surgery after free flap reconstruction as the transferred tissue can be still dependent on its pedicle.