Dextrans in microsurgery: A review

Evidence-Based Approaches to Anticoagulation in Reconstructive Microsurgery-A Systematic Literature Review

This systematic review addresses the crucial role of anticoagulation in microsurgical procedures, focusing on free flap reconstruction and replantation surgeries. The objective was to balance the prevention of thrombotic complications commonly leading to flap failure, with the risk of increased bleeding complications associated with anticoagulant use. A meticulous PubMed literature search following Evidence-Based-Practice principles yielded 79 relevant articles, including both clinical and animal studies. The full-texts were carefully reviewed and evaluated by the modified Coleman methodology score. Clinical studies revealed diverse perioperative regimens, primarily based on aspirin, heparin, and dextran. Meta-analyses demonstrated similar flap loss rates with heparin or aspirin. High doses of dalteparin or heparin, however, correlated with higher flap loss rates than low dose administration. Use of dextran is not recommended due to severe systemic complications. In animal studies, systemic heparin administration showed predominantly favorable results, while topical application and intraluminal irrigation consistently exhibited significant benefits in flap survival. The insights from this conducted systematic review serve as a foundational pillar towards the establishment of evidence-based guidelines for anticoagulation in microsurgery. An average Coleman score of 55 (maximum 103), indicating low overall study quality, however, emphasizes the need for large multi-institutional, randomized-clinical trials as the next vital step.

The Effects of Dextran on Postoperative Thrombosis and Hemodilution in Microvascular Head and Neck Reconstruction

BACKGROUND

Free tissue transfer is an integral part of reconstructive head and neck surgery today. Although increased experience and refinements in techniques have minimized flap loss, pharmacological agents have been used to prevent thrombus formation and flap failures, despite their questionable effectiveness. The aim of this study is to investigate the use of dextran 40 in thrombosis prophylaxis, as well as its effects on blood coagulability and flap survival.

METHODS

This is a retrospective analysis of 176 free flaps performed at University Hospital Dubrava, Zagreb, Croatia, during a 4-year period. A comparison was made between 2 patient groups, based on their respective postoperative prophylaxis protocols. All patients were treated with low-molecular-weight heparin as deep vein thrombosis prevention, until patient mobilization. Group 1 was on dextran 40 protocol, whereas group 2 did not receive additional treatment. Primary outcome of the study was determined as flap loss rate, whereas secondary outcome was evaluated as the rate of thrombosis or hemorrhage. The hemodilution potential of dextran 40 was examined through blood count laboratory values.

RESULTS

Total flap survival rate was 90.34%. There were 16 free flap losses and 1 partial loss overall. Anastomoses were re-explored in a total of 27 cases, of which 17 were salvaged. There were 29 events of hemorrhage or arterial or venous thrombosis: 17 in group 1 and 12 in group 2. A sum of 26 incidences of other postoperative complications was recorded, 13 in each group. Hemodilution status showed a statistically significant reduction in erythrocyte count and hemoglobin and hematocrit levels in the group receiving dextran 40, on postoperative days 1 and 3, but no such effect was observed on postoperative platelet count.

CONCLUSIONS

Although dextran 40 has been shown to have a valuable effect on hemodilution, which is beneficial in microsurgery, it did not demonstrate better outcomes in terms of flap survival. Because it can cause serious systemic complications, it is better not to administer it routinely. However, its important influence on reduction in erythrocyte count and hemoglobin and hematocrit levels should be further investigated.

Postoperative Management and Rehabilitation of the Replanted or Revascularized Digit

Postoperative care of amputated digits begins before replantation. Detailed informed consent should be obtained and completion amputation discussed if revascularization is not ultimately successful. Complications and failure of the replanted digit should also be addressed. Postoperative pharmacologic treatment should consist of aspirin, at minimum. Complications, such as venous congestion or occlusion, and arterial thrombosis, should be dealt with expediently. Digital motion rehabilitation should start after 5 to 7 days of digital viability and splinting of the affected digit. Early protective motion protocol is implemented to maintain digital motion with emphasis on tendon glide and joint motion.

The use of dextran post free tissue transfer

Dextran has been used in microsurgery to reduce the risk of free tissue transfer loss. A number of regimens which vary considerably in dosage and timing have been published in the literature. Using a postal questionnaire, a survey was conducted to delineate the current practise of UK plastic surgeons. Data were received from 161 plastic surgeons in 51 units (response rate of 61%). Forty-five percent of microsurgeons routinely use dextran post-operatively whilst 29% use alternative thromboprophylaxis. The indications, post-operative regimes and duration of administration of dextran vary significantly amongst surgeons and units. The reported success rates of free tissue transfer and digital replants were 97 and 85.1%, respectively, and was not significantly affected by the use of dextran. We conclude that there is considerable variation amongst UK plastic surgeons regarding thromboprophylaxis post microsurgery. Our data suggest that the use of dextrans does not affect free tissue transfer success rates.

Surgical reconstruction in patients with cancer of the head and neck

Reconstructive surgical techniques have greatly changed the treatment approach for patients with cancer of the head and neck. These techniques provide head and neck surgeons the flexibility of performing tumor resection without concerns about the repair of the final defect and significantly increase the quality of life in patients who have undergone ablative surgery by providing better cosmetic and functional outcome after cancer resection. Reconstruction of the defects after ablative surgery for head and neck cancer includes various options, and each option has its own advantages and disadvantages. Techniques for head and neck reconstruction are summarized in this article along with recent advances in their application.