Efficacy of epidural anesthesia in free flaps to the lower extremity

The Effect of Regional Anaesthesia on Free Flap Survival in Lower Extremity Reconstructions

Background

The effect of different modalities of anaesthesia in microvascular free flap surgery has been a topic of ongoing debate. Comparative data to study the effect of general anaesthesia and regional anaesthesia in the form of peripheral nerve blocks (PNBs) on lower extremity free flap survival is lacking to date. This study aims to elucidate the effect of regional anaesthesia on flap survival in lower extremity free flap reconstructions.

Methods

A retrospective cohort study of all patients who underwent free vascularised flap reconstruction of the lower extremities between 2012 and 2021 at the Amsterdam University Medical Centre (UMC), The Netherlands, and between 2019 and 2021 at the Radboud UMC, Nijmegen, The Netherlands. In this cohort, we analysed partial and total flap failures.

Results

In this cohort, 87 patients received a total of 102 microvascular free flap reconstructions of the lower extremity. In 20.5% of these operations, patients received a supplemental PNB. Total flap failure was 23.8% in the regional anaesthesia group compared to 21% in the group with general anaesthesia only (p = 0.779). Operation time was longer for patients with regional anaesthesia (p = 0.057). Length of stay was on average 2 days shorter for patients with supplemental regional anaesthesia (p = 0.716).

Discussion

This is the largest cohort comparing flap survival in patients receiving general anaesthesia to general anaesthesia with a PNB in lower extremity reconstructions to date. We cannot attribute a significant beneficial or detrimental effect of regional anaesthesia to flap survival. High failure rates stress the need for future studies.

How to cite this article

Koster ITS, den Os MM, Rutten MVH, et al. The Effect of Regional Anaesthesia on Free Flap Survival in Lower Extremity Reconstructions. Strategies Trauma Limb Reconstr 2024;19(1):15-20.

Efficacy of Combined Spinal-Epidural Anesthesia for Lower Extremity Microvascular Reconstruction

INTRODUCTION

Some surgeons have raised concerns regarding the sympathectomy-like effect of epidural anesthesia during lower limb microvascular reconstruction. The combined spinal-epidural (CSE) anesthetic technique incorporates several benefits of spinal and epidural techniques in a single approach. The aim of this study was to analyze the postoperative outcomes of patients undergoing soft-tissue reconstruction of the lower limb by implementing the CSE anesthesia approach.

METHODS

We reviewed medical records from patients who underwent lower limb reconstructive procedures under CSE anesthesia with free tissue transfer from January 2017 to December 2020. We evaluated the postoperative outcomes.

RESULTS

Thirty-eight patients underwent microvascular reconstructive procedures of the lower extremity over the study period. The average age and BMI were 38.4-year and 28 kg/m2. All patients only had one postoperative rescue dose with epidural anesthesia. The most common type of flap used was the anterolateral thigh flap (53%). The average splinting time and length of stay (LoS) were 8.4 days and 18.4 days, respectively. Donor-site complications included wound dehiscence (3%) and surgical site infection (3%). Recipient-site complications included partial flap loss (8%) and total flap loss (10%). No pro re nata morphine analgesia was used. Tramadol and/or ketoprofen were administered for postoperative analgesia. The average time to start physiotherapy and to resume daily activities were 10 days and 29 days, respectively.

CONCLUSIONS

The CSE anesthesia for microvascular reconstruction of the lower limb demonstrated a similar success rate compared to historical records. CSE provided adequate pain management and none of the patients required postoperative monitoring in the ICU.

Leech Therapy Protects Free Flaps against Venous Congestion, Thrombus Formation, and Ischemia/Reperfusion Injury: Benefits, Complications, and Contradictions

The use of free cutaneous or myocutaneous flaps in some surgeries, especially in reconstructive surgeries, is routine and imperative; nevertheless, it is controversial because of fear of flap loss due to tissue congestion and partial or complete necrosis. Different mechanisms are discussed in this process, and based on the involved mechanisms, various agents and approaches are suggested for flap salvage. Among these agents and strategies, leech therapy (hirudotherapy) can be a valuable complementary treatment; however, in this way, full attention should be given to all beneficial and harmful aspects to reach the best results. This study included a literature review of the essential complications following free tissue transfer and explained the effects of leech therapy for the respective complications. Based on the review of the literature, the essential complications following free tissue transfer were (I) venous obstruction and congestion, (II) delay in blood flow reestablishment, (III) ischemia/reperfusion injuries, and (IV) thrombus formation. Leech therapy can protect free flaps against the mentioned complications as a complementary treatment. Leech therapy is an appropriate complement, however, not a definite approach for flap salvage. Therefore, in some patients, other alternative methods or even flap removal may be a better option.

Epidural Anesthesia and Arterial Maximal Flow Velocity of Free Flap in Patients Having Microvascular Lower Extremity Reconstruction: A Randomized Controlled Trial

BACKGROUND

One of the critical factors for free flap survival is to maintain adequate perfusion. The authors evaluated the effect of epidural anesthesia on arterial maximal flow velocity of the free flap in microvascular lower extremity reconstruction.

METHODS

This is a prospective randomized study where patients were allocated to receive either combined general-epidural anesthesia (epidural group, n = 26) or general anesthesia alone (control group, n = 26). After injecting epidural ropivacaine 10 ml in the epidural group, the effect on arterial maximal flow velocity of the free flap was analyzed using ultrasonography. The primary outcome measurement was the arterial maximal flow velocity 30 minutes after establishing the baseline. Intraoperative hemodynamics and postoperative outcomes such as postoperative pain, opioid requirements, surgical complications, intensive care unit admission, and hospital length of stay were also assessed.

RESULTS

The arterial maximal flow velocity 30 minutes after the baseline measurement was significantly higher in the epidural group (35.3 ± 13.9 cm/second versus 23.5 ± 8.4 cm/second; p = 0.001). The pain score at1 hour postoperatively and opioid requirements at 1 and 6 hours postoperatively were significantly lower in the epidural group [3.0 (interquartile range, 2.0 to 5.0) versus 5.0 (interquartile range, 3.0 to 6.0), p = 0.019; 0.0 μg (interquartile range, 0.0 to 50.0 μg) versus 50.0 μg (interquartile range, 0.0 to 100 μg), p = 0.005; and 46.9 μg (interquartile range, 0.0 to 66.5 μg) versus 96.9 μg (interquartile range, 41.7 to 100.0 μg), p = 0.014, respectively]. There were no significant differences in intraoperative hemodynamics or other postoperative outcomes between the two groups.

CONCLUSION

Epidural anesthesia increased the arterial maximal flow velocity of the free flap and decreased postoperative pain and opioid requirements in microvascular lower extremity reconstruction.

CLINICAL QUESTION/LEVEL OF EVIDENCE

Therapeutic, I.

Improvement of Superficial and Deep Cutaneous Microcirculation Due to Axillary Plexus Anesthesia Impaired by Smoking

BACKGROUND

Understanding microvascular physiology is key to any reconstructive procedure. Current concepts in anesthesia increasingly involve regional peripheral nerve blockade during microvascular reconstructive procedures. Whereas favorable effects on perfusion due to these techniques have been reported earlier, little evidence focusing on its effects in most peripheral vascular compartments is available.

METHODS

A total of 30 patients who were to receive axillary plexus blockade (APB) were included. Microcirculatory assessment of the dependent extremity was conducted utilizing combined laser-Doppler flowmetry and white light spectroscopy. Two probes (1-2 and 7-8 mm penetration depth) were used to assess changes in microcirculation.

RESULTS

APB resulted in significant changes to both superficial and deep cutaneous microcirculation. Changes in blood flow were most prominent in superficial layers with a maximum increase of +617% compared to baseline values. Significantly lower values of +292% were observed in deep measurements. Consecutively, a significant enhancement in tissue oxygen saturation was observed. Further analysis revealed a significant impairment of perfusion characteristics due to reported nicotine consumption (max Bf: +936% vs. +176%).

CONCLUSION

Cutaneous microcirculation is strongly affected by APB, with significant differences regarding microvascular anatomy and vascular physiology. Smoking significantly diminishes the elicited improvements in perfusion. Our findings could influence reconstructive strategies as well as dependent perioperative anesthetic management.

The effect of paravertebral block on maxillofacial free flap survival

The purpose of this study was to investigate whether continuous paravertebral block at levels T1 and T2 with bupivacaine infusion can improve the survival of free flaps in maxillofacial reconstruction. The study was designed as a randomized controlled trial and included 36 adult patients scheduled for maxillofacial free flap reconstruction under general anesthesia. Patients were randomly divided into two groups: patients in group A received continuous paravertebral block at levels T1 and T2, while patients in group B served as controls. Postoperatively, a skin thermometer was used to assess the skin temperature. Perfusion of the flaps was evaluated by analysis of skin color, turgor, and capillary refill. Survival of the free flap was recorded. The surface temperature of the reconstructive flap, skin color score, and capillary refill score were significantly higher in group A patients than in group B patients during follow-up. The total perfusion score was significantly higher in group A than in group B at 16h and 20h postoperative (P=0.041 and P=0.039, respectively). Re-operation was recorded in three cases in group B (16.7%) (P=0.031). Continuous paravertebral block at levels T1 and T2 can increase the skin temperature and improve skin color and capillary refilling, which are indices of adequate tissue perfusion and indicate maxillofacial free flap survival.

Emerging paradigms in perioperative management for microsurgical free tissue transfer: review of the literature and evidence-based guidelines

BACKGROUND

Microsurgical free tissue transfer has become an increasingly valuable technique in reconstructive surgery. However, there is a paucity of evidence-based guidelines to direct management. A systematic review was performed to define strategies to optimize perioperative management.

METHODS

A systematic review of the literature was performed using key search terms. Strategies to guide patient management were identified, classified according to level of evidence, and used to devise recommendations in seven categories: patient temperature, anesthesia, fluid administration/blood transfusion, vasodilators, vasopressors, and anticoagulation.

RESULTS

A total of 106 articles were selected and reviewed. High-level evidence was identified to guide practices in several key areas, including patient temperature, fluid management, vasopressor use, anticoagulation, and analgesic use.

CONCLUSIONS

Current practices remain exceedingly diverse. Key strategies to improve patient outcomes can be defined from the available literature. Key evidence-based guidelines included that normothermia should be maintained perioperatively to improve outcomes (level of evidence 2b), and volume replacement should be maintained between 3.5 and 6.0 ml/kg per hour (level of evidence 2b). Vasopressors do not harm outcomes and may improve flap flow (level of evidence 1b), with most evidence supporting the use of norepinephrine over other vasopressors (level of evidence 1b). Dextran should be avoided (level of evidence 1b), and pump systems for local anesthetic infusion are beneficial following free flap breast reconstruction (level of evidence 1b). Further prospective studies will improve the quality of available evidence.

Regional anesthesia alone for pediatric free flaps

Microvascular surgery plays an important reconstructive role in the pediatric population. Successful outcomes rely on surgical technique as well as anesthesia. Regional anesthesia contributes to successful free tissue transfer through sympathetic blockade, postoperative pain control, and elimination of risks and costs associated with general anesthesia. While regional anesthesia in microsurgery is discussed in the literature for adult and elderly patients, no studies focus on the pediatric population. Accordingly, this paper reviews 20 pediatric patients undergoing microvascular surgery (anterolateral thigh, n = 9; gracilis, n = 3; toe transfer, n = 6; and fibula, n = 2) with regional anesthesia and sedation. All patients underwent spinal epidural anesthesia, and seven also received brachial plexus blocks. The average duration of anesthesia was 3-4 h (anterolateral thigh (ALT) and gracilis) and 6-8 h (toe transfer and fibula). No anesthesia-related complications or flap failures occurred. We conclude that regional anesthesia has important benefits in pediatric microsurgery and it is a safe and cost-effective alternative to general anesthesia.

A comparison of the effects of epidural and spinal anesthesia with ischemia-reperfusion injury on the rat transverse rectus abdominis musculocutaneous flap

The purpose of this study is to compare the effects of spinal and epidural anesthesia on a rat transverse rectus abdominus myocutaneous flap ischemia-reperfusion injury model.Forty Sprague-Dawley rats were divided into 4 experimental groups: group I (n = 10), sham group; group II (n = 10), control group; group III (n = 10), epidural group; and group IV (n = 10), spinal group. After the elevation of the transverse rectus abdominus myocutaneous flaps, all groups except for the sham group were subjected to normothermic no-flow ischemia for 4 hours, followed by a reperfusion period of 2 hours. At the end of the reperfusion period, biochemical and histopathological evaluations were performed on tissue samples.Although there was no significant difference concerning the malonyldialdehyde, nitric oxide, and paraoxonase levels in the spinal and epidural groups, the total antioxidant state levels were significantly increased, and the total oxidative stress levels were significantly decreased in the epidural group in comparison to the spinal group. The pathological evaluation showed that findings related to inflammation, nuclear change rates and hyalinization were significantly higher in the spinal group compared with the epidural group.Epidural anesthesia can be considered as a more suitable method that enables a decrease in ischemia-reperfusion injuries in the muscle flaps.

Drip infusion method as a useful indicator for identification of the epidural space

BACKGROUND

Cervical epidural anesthesia (CEA) is used for pain control and surgical procedures of the head and neck or upper arm areas. However, the failure rate of CEA is reported to be high, is the failure rate being quite higher than other sites, because of the anatomical differences of the cervical spine. We hypothesized that the loss of resistance (LOR) method combined with the drip infusion method for confirmation of the cervical epidural space can reduce the failure rate. This study investigated the usefulness of the drip infusion method.

METHODS

One hundred chronic renal failure patients undergoing arteriovenous bridge graft for hemodialysis at the upper arm under cervical epidural anesthesia were recruited for this study. In the cervical epidural puncture, we identified the cervical epidural space using a combination of the LOR method with the drip infusion method. After confirmation of the epidural space with LOR method, we decided it was the true epidural space when fluid dripping to the space was present. Otherwise, if fluid dripping was not present, we designated it was pseudo LOR, and we found the true epidural space using the drip infusion method only.

RESULTS

In all cases, the combined LOR with drip infusion method, identify the epidural space.

CONCLUSIONS

Combined LOR with drip infusion method is an efficacious method for the confirmation of the cervical epidural space.

Microvascular surgery

LEARNING OBJECTIVES

After reading this article, the participant should be able to: 1. Describe the common room set-up, medical considerations, and technical equipment necessary to perform microvascular surgery. 2. Describe the common arterial and venous techniques in performing microvascular surgery. 3. Recognize the common flap types along with their vascular supply and innervation used for microvascular surgery. 4. Describe common techniques for flap monitoring. 5. Describe techniques and medications for thrombolytic therapy. 6. Describe common medical conditions that may preclude an optimal result in microvascular surgery.

SUMMARY

This article will explore common approaches to microsurgery. It is anticipated that the readers can utilize this article for maintenance of certification educational components and take the principles outlined and apply them to their daily practice.

Three episodes of gracilis free muscle transfer under epidural anaesthesia

The use of regional anaesthesia in major surgery is associated with a lower risk of complications. However, recent evidence suggests that a vascular steal phenomenon may result in a reduction of free flap blood flow in such patients. We report three cases of free gracilis transfer under epidural anaesthesia in patients who were considered high risk for general anaesthesia. Our experience suggests that there remains an important role for epidural anaesthesia in the management of patients undergoing lower limb free flap reconstruction. The inability to undergo general anaesthesia does not preclude free flap surgery in carefully selected patients.

Effects of epidural anesthesia on microcirculatory blood flow in free medial saphenous fasciocutaneous flaps in dogs

OBJECTIVE

To assess the effects of epidural anesthesia using lidocaine on microcirculatory blood flow, volume, and velocity in free fasciocutaneous flaps in dogs. Study Design-In vivo experimental investigation. Animal Population-Ten adult dogs weighing 20 to 25 kg.

METHODS

A medial saphenous fasciocutaneous free flap was removed and an orthotopic transfer was performed by anastomosing the primary flap vessels back to the medial saphenous vessels. Blood flow (mL(LD)/min/100 g), volume (%volume or tissue hematocrit) and velocity (mm/s) in the flap were recorded throughout the procedure. After epidural anesthesia, blood flow, volume, and velocity values were again recorded.

RESULTS

Microcirculatory blood flow, volume, and velocity, as measured by a laser-Doppler flowmeter, failed to reveal any significant changes over time. Immediately after epidural anesthesia, mean arterial pressure was significantly reduced and remained depressed throughout the experimental procedure.

CONCLUSIONS

Epidural anesthesia combined with general anesthesia does not improve microcirculatory flow in free flaps in the pelvic limbs of dogs. No significant change in blood flow to the medial saphenous fasciocutaneous free flap occurred after division and anastomosis of the vascular pedicle.

CLINICAL RELEVANCE

We recommend that epidural anesthesia with 2% lidocaine be used with caution in dogs undergoing microvascular free-flap transfer.

Combined regional and general anaesthesia

Combining regional and general anaesthesia can have many advantages, particularly in patients undergoing major thoracic, abdominal or orthopaedic surgery. The use of regional anaesthetic techniques in anaesthetized children is an accepted standard of care, because needle and procedure phobias are very common and can result in severe anxiety, an inability to cooperate and sudden unpredictable movement. Epidural local anaesthetics have the potential of attenuating sympathetic hyperactivity, maintaining bowel peristalsis, sparing the use of opioids, and facilitating postoperative feeding and out-of-bed activity. Catheter techniques allow excellent and prolonged postoperative analgesia using epidural or peripheral nerve blocks. However, the superiority of regional techniques for hip fracture surgery and carotid endarterectomy has been disputed in several recent studies. As part of the combination technique, epidural block may in fact decrease blood flow in free flap surgery by a steal phenomenon, and increase intrapulmonary shunting during one-lung ventilation. The present review focuses on the use of a combination of regional and general anaesthesia for a variety of surgical procedures. It also compares the two anaesthetic techniques in elderly patients. The review is based on studies published during the past year.

Experimental prevention of free flap thrombosis. II: Normovolemic hemodilution for thrombosis prevention

A microvascular free flap failure model consisting of raising an epigastric groin flap on the femoral pedicle, while cutting the femoral artery, twisting it around the femoral vein and resuturing it, has been previously described. As it was being evaluated, normovolemic hemodilution as a means to prevent thrombosis was simultaneously assessed using an additional experimental group. Twenty percent of the blood mass of each rat was taken and replaced with a hydroxyethyl starch solution immediately before surgery. Only 14 out of 20 anastomoses presented with thrombosis (13 venous and one mixed), as opposed to 19 out of 20 animals operated on without hemodilution (P< 0.05). Normovolemic hemodilution appears to be an effective method of reducing microvascular free flap failure.

MICROSURGICAL COMPOSITE TISSUE TRANSPLANTATION: A CLINICAL TRIAL

Twenty four patients suffering from various ailments necessitating flap cover were treated with composite tissue transplantation by microsurgical techniques from July 1992 to July 1996. There were 21 males and 3 females in the 10 to 50 years age group. Four patients were provided flap cover on the face for congenital lesions and twenty patients required flap cover for sub acute/chronic trauma. The radial artery forearm and latissimus dorsi were the most commonly used flaps in this study. Seventeen patients had excellent and four patients had acceptable cosmetic and functional results. Three flaps were lost due to vascular problems.

Effects of extradural anesthesia on microcirculatory blood flow in free latissimus dorsi musculocutaneous flaps in pigs

Free musculocutaneous flaps are used frequently in plastic surgery to reconstruct soft-tissue defects after radical cancer surgery and trauma. Despite improved surgical techniques, some of these flaps fail due to insufficient blood supply. Extradural anesthesia causes both sensory (pain relief) and sympathetic (vasodilatation) block that may be advantageous in free-flap surgery. This hypothesis, however, has not yet been studied. An experimental model in pigs was developed in which clinical conditions for anesthesia and microvascular surgery on the lower extremity were simulated as closely as possible. The effects of extradural anesthesia as well as phenylephrine infusion, combined with general anesthesia, on central hemodynamics and on microcirculatory blood flow in skin and muscle of the latissimus dorsi free flap were studied. After surgery, seven animals received extradural anesthesia during stable normovolemic conditions and another seven during mild hypovolemia (10 percent blood loss). The extradural block was objectively evaluated using the temporal summation test. Thirty minutes after induction of extradural anesthesia, the animals received an intravenous infusion of phenylephrine 1 microgram/kg per minute over a period of 15 minutes. Multichannel laser-Doppler flowmetry was used to measure microcirculatory blood flow in skin and muscle of the free flap as well as in control skin and muscle on the same extremity simultaneously. In normovolemic animals, extradural block caused a 10 percent decrease in mean arterial pressure and cardiac output and an approximately 20 percent decrease in microcirculatory blood flow in both the skin and muscle of the flap (all changes were nonsignificant). In slightly hypovolemic animals, however, extradural anesthesia caused a significant decrease in cardiac output (31 percent, p < 0.01), mean arterial pressure (24 percent, p < 0.01), and in mean blood flow in the flap muscle (22 percent, p < 0.05) and skin (20 percent, p < 0.05). During phenylephrine infusion, mean arterial pressure increased significantly (p < 0.05) in both hypovolemic and normovolemic animals, while cardiac output and microcirculatory blood flow in the flap remained almost unchanged. Extradural anesthesia does not improve microcirculatory blood flow in free musculocutaneous flaps in pigs. It causes a significant decrease in cardiac output, mean arterial pressure, and microcirculatory blood flow in slightly hypovolemic animals. During phenylephrine infusion, the microcirculatory blood flow in free flaps slightly improves due to the increase in mean arterial pressure. We suggest that extradural anesthesia for microvascular surgery should be used with great caution until human data are available.

Continuous cervical epidural anesthesia in reconstructive hand surgery

Continuous cervical epidural anesthesia was used for 17 operations in 16 patients undergoing immediate reconstructive surgery after upper-extremity injuries or tumor resection and was continued for postoperative pain management. Routine hemodynamics, arterial blood gases, plasma bupivacaine levels, and skin temperatures were recorded before and after the block. The surgery time ranged from 3 to 18 hours. Postoperative pain management was maintained for up to 6 days. The blocks were adequate for surgery and postoperative pain treatment in all cases. There were no signs or symptoms indicating local anesthetic toxicity. Circulatory and respiratory integrity was well maintained. The patients were all ambulatory the day after surgery and could start physiotherapy immediately. This regional anesthesia technique may have significant advantages over branchial plexus block or general anesthesia for lengthy surgical procedures of the upper extremity.