Evaluation of survival in digital replantation with thermometric monitoring

What is the role and importance of temperature measuring devices in finger replantation surgery?

Background/Aim: Post-operative circulation monitoring is very important in replantation surgery. Vascular pathologies that occur can be detected and undergo intervention as a result of strict follow-up protocols, thus increasing success rates. Although many alternative methods for circulation monitoring are available, no gold standard for such monitoring exists. This study aimed to find a more reliable and easier method by comparing different temperature measurement methods to facilitate the follow-up of patients who underwent finger replantation after the operation. Methods: This study was designed as a retrospective case series study. It was conducted between January 2017 and December 2019. Eighteen patients who presented with flexor zone 2 finger amputations and who had undergone replantation surgery were included in the study. The cases were randomly divided into two equal groups. While the finger temperature of the patients in the first group was measured with an indoor/outdoor temperature device, the measurement was obtained using a non-contact infrared thermometer in the second group. Results: In our study, the mean age of group 1 was 44.33 years, and the mean age of group 2 was 45. Eleven fingers from  nine patients in the group 1 and 10 fingers in 9 patients in the group 2 were replanted. All amputated finger replantation were performed. The patients stayed in the hospital for five days, were followed, and treated. The success rate based on living fingers was 54.54% in group 1 and 60% in group 2. The mean measured finger temperatures were 34.12 and 35.76 °C in groups 1 and 2, respectively. In group 1, the mean time of measurement was calculated as 4 min 31 s. In the group 2, the mean time of measurement was calculated as 1 s. In the study, two measurement tools were used to determine fingertip temperatures in the two similar groups. Conclusion: In our study, we found that infrared non-contact temperature measuring devices are both reliable and useful as a heat meter in the follow-up of finger after the replantation operation.

Pediatric Replantation and Revascularization

Replantation and revascularization in the pediatric extremity has unique challenges that provide a fertile field of research and clinical experience. Children regenerate peripheral nerves rapidly, resulting in good sensory and motor function. They adapt well to functional deficits and mismatch errors of reinnervation. The technical aspects of microsurgical care in children can be challenging because the structures are small. Additional technical challenges include preservation of growth centers, prevention of vasospasm, protection of the reconstruction, and psychosocial care. Despite these challenges, children show excellent functional outcomes with minimal complications.

Survival Factors in Digital Replantation: Significance of Postoperative Anaemia

Two hundred and fifty-two consecutive digital replantations and revascularizations in 201 patients were retrospectively reviewed to determine factors influencing survival. Children under 9 years of age, women, complete amputations, blood transfusions and secondary thrombectomy were poor prognostic factors. In addition, low haemoglobin and haematocrit levels during the postoperative period were associated with a higher failure rate. Inappropriate use of anticoagulants and excessive postoperative anaemia should be avoided following replantation.

Economic analysis of revision amputation and replantation treatment of finger amputation injuries

BACKGROUND

The purpose of this study was to perform a cost-utility analysis to compare revision amputation and replantation treatment of finger amputation injuries across a spectrum of injury scenarios.

METHODS

The study was conducted from the societal perspective. Decision tree models were created for the reference case (two-finger amputation injury) and seven additional injury scenarios for comparison. Inputs included cost, quality of life, and probability of each health state. A Web-based time trade-off survey was created to determine quality-adjusted life-years for health states; 685 nationally representative adult community members were invited to participate in the survey. Overall cost and quality-adjusted life-years for revision amputation and replantation were calculated for each decision tree. An incremental cost-effectiveness ratio was calculated if a treatment was more costly but more effective.

RESULTS

The authors had a 64 percent response rate (n = 437). Replantation treatment had greater costs and quality-adjusted life-years compared with revision amputation in all injury scenarios. Replantation of single-digit injuries had the highest incremental cost-effectiveness ratio ($136,400 per quality-adjusted life-year gained). Replantation of three- and four-digit amputation injuries had relatively low cost-to-benefit ratios ($27,100 and $23,800 per quality-adjusted life-year, respectively). Replantation for distal thumb amputation had a relatively low incremental cost-effectiveness ratio ($26,300 per quality-adjusted life-year) compared with replantation of nonthumb distal amputations ($60,200 per quality-adjusted life-year).

CONCLUSIONS

The relative cost per quality-adjusted life-year gained with replantation treatment varied greatly among the injury scenarios. Situations in which indications for replantation are debated had higher cost per quality-adjusted life-year gained. This study highlights variability in value for replantation among different injury scenarios.

Upper extremity and digital replantation

Digital replantation has become a well-established technique among reconstructive hand surgeons. Numerous replantation centers around the world have published series with impressive survival rates. The ultimate goal of replantation is the restoration of normal hand or digital function; thus, replantation success is not solely related to the outcome of the microvascular anastomosis, but also to the adequacy of bone, tendon, skin, and nerve repairs. In this manuscript, we review the literature on upper extremity and digital replantation from its historical background to current surgical outcomes, outlining surgical indications and contraindications, and the preoperative, operative, and postoperative management of these patients.

Wireless infrared thermometer in the follow-up of finger temperatures

After replantation surgery it is helpful to use temperature monitoring in order to detect vascular problems early. One of the methods currently employed is to use a thermometer with a wired probe attached to the tissue being monitored. An infrared wireless thermometer, commonly used in industry, measures temperatures of surfaces without actually touching them. The purpose of this study was to evaluate the efficacy of infrared wireless thermometer technology for monitoring finger temperature. Finger temperatures of 38 volunteers were measured using the infrared wireless thermometer. A traditional wired thermometer was used as control. The measurements of both thermometers were similar when the temperature was 31.5 degrees and over, with no statistical differences (mean difference 0.06 degrees , P=0.521). At lower temperatures, however, the wireless infrared thermometer showed slightly lower temperature values (mean difference 1.01 degrees , P<0.001). There was no difference between the finger temperatures of smokers and non-smokers. There is potential for the wireless infrared thermometer to be used as an easier alternative to the traditional wired thermometer in monitoring temperatures of revascularised or replanted parts including digital replants. Further clinical studies would be warranted.

Pediatric upper extremity replantation

The evolution of microsurgical technique has led to increasing success with pediatric replantation. The broader inclusion criteria for pediatric replantation, together with the greater technical demands of repair and the less favorable mechanism of pediatric amputations (crush-avulsion), yield a slightly lower overall survival rate than in adults. The superior nerve and soft tissue regenerative capacity of children appears to produce better functional outcomes. Nonetheless, the issue of cosmesis and developing self-image in a child may have ramifications beyond a simple calculus of range of motion and strength variables--hence the imperative that microsurgical salvage be attempted in pediatric upper-extremity amputations.

Replantation in the mutilated hand

With the evolution of surgical techniques and scientific technology, replantation has become more refined, establishing specific indications for replantation, rituals for preparation, efficient techniques to ultimately minimize ischemia times, improved survival rates, guidelines for postoperative care, strategies for treating complications, and goals for outcomes. Patient satisfaction hinges on their level of expectation as defined and explained in the preoperative discussion and informed consent. Studies have demonstrated patients can be expected to achieve 50% function and 50% sensation of the replanted part. Initially all that was amputated was replanted, as surgeons adopted the philosophy of George C. Ross (1843-1892): "Any fool can cut off an arm or leg but it takes a surgeon to save one." Forty years after the first replant (1962-2002), however, we recognize the ultimate goal: not merely to preserve all living tissue through nonselective replantation, but rather to preserve one's quality of life by improving their function and appearance. This objective to care for the patient with the intent to optimize function and appearance is important not only to the replantation of amputations but to all mutilated hand injuries.

Routine monitoring in patients with free tissue transfer by laser-Doppler flowmetry

The use of laser Doppler flowmetry (LDF) was tested in 108 consecutive patients, who underwent free tissue transfer at our institution between December, 1988, and June, 1990. Sixteen patients (14.8%) suffered vascular complications, which could be detected in all cases earlier by LDF than by clinical examination alone. LDF therefore prompted faster surgical intervention in these cases, allowing flap salvation in 9.3% (n = 10). Difficulties had to be noted in diagnosing venous thrombosis by means of the LDF due to sometimes unspecific alterations in LDF signals. Technical improvement of LDF might lead to a higher diagnostic accuracy if venous thrombosis occurs.

Present status of replantation in Japan

We conducted a survey among 94 members of the Japanese Society of Reconstructive Microsurgery on the present status of replantation in Japan. The results indicate that 9,664 extremities were replanted (157 upper arms, 415 forearms, 471 hands, 8,320 digits, 33 thighs, 103 calves, 37 feet, and 128 toes); 8,227 replants survived, for a success rate of 85%. The survival rate was over 90% in 23 hospitals, and 7 of these hospitals replanted more than 100 limbs. Postoperative treatment consisted of continuous intravenous infusion of urokinase (120,000-240,000 U/day), heparin (10,000-20,000 U/day), and prostaglandin E1 (80-120 micrograms/day) for 3-10 days. Fifty-six surgeons attempted replantation whenever the patient requested it. At Nara Medical University, continuous local intra-arterial infusion of anticoagulants and fibrinolytic agents has increased the survival rate of the replantation to 97%, compared with 88% when using intravenous infusion.

Techniques of postoperative blood flow monitoring after free tissue transfer: an overview

Ever since free tissue transfer has been established in microsurgery, success rates have greatly improved over the years, partly due to improved technical performance of microvascular anastomoses with better optical and instrumental aids. However, flap failure still occurs in 5-10%, mainly due to blood vessel thrombosis within the first 24 postoperative hours. Salvation rates of failing free tissue transfers can be optimized by in-time diagnosis of irreversibly compromised tissue blood flow and immediate operative reexploration. Therefore, there is a special demand for adequate and reliable postoperative monitoring techniques. This article gives an overview of all monitoring techniques, which have been performed both in the experimental and clinical setting thus far.

Replantation in children

The authors have replanted 162 parts in 120 children over the past 15 years. The youngest patient, undergoing successful replantation, was aged 7 months, 3 weeks. Unlike an adult, any child suffering a traumatic amputation should be considered for a possible replantation. Replantation should consist of minimal bone shortening to preserve epiphyseal plates, with repair of all severed structures. Longitudinal K-wires usually provide adequate fixation. Our survival rate for complete replantation in children under the age of 16 years is 77%. Long-term study showed that continued skeletal growth occurred and the digit attained 81% of normal longitudinal length at maturity. Recovery of sensibility in the replanted digit is nearly as good as for isolated digital nerve repair. Patient and parent satisfaction is high when replantation is successful, with uniform approval of the extensive effort required.

Toe transfer for congenital hand defects

Toe-to-hand transfer is a well-established reconstructive option for certain congenital hand anomalies. It is the only technique which can add growth potential to the immature skeleton. Toe transfer is best suited for constriction ring amputations, which have relatively normal proximal anatomy. Transfers should be performed early in life to avoid lack of cortical integration of the new part. Anatomic variations of both hand and foot are often encountered, which influence both operative approach and functional prognosis. Indications, techniques, and complications are reviewed.

Factors involved in salvaging ischaemic rabbit skin flaps: ATP and free radicals but not thromboxane

Rabbit epigastric free flaps were subjected to ischaemia at 25 degrees C for 24 hours. At the time of revascularisation the flaps were infused intra-arterially with one of the following: Hanks balanced salt solution (control), the high energy phosphates PEP/ATP, the thromboxane synthetase inhibitor dazoxiben hydrochloride, the free radical scavenger SOD and a combination of all these agents (treated groups). Control ischaemic flap survival at post-ischaemia day 7 was 23.5%, while the other treatments resulted in improved flap survival of 43.5% (p less than 0.025), 23.5% (not significant), 38.6% (p less than 0.05) and 35.7% (p less than 0.05) respectively. None of these agents improved post-ischaemic blood flow significantly. These results would support the use of PEP/ATP or SOD in the clinical treatment of failing ischaemic skin flaps but do not support the use of dazoxiben hydrochloride.

Correlation of viability and laser Doppler flowmetry in ischemic flaps

Microvascular blood flow was measured by a laser Doppler flowmeter in rabbit epigastric island flaps made ischemic at 37 degrees C for either 6.5 hr (Group 1; n = 13) or 17.5 hr (Group 2; n = 4). Contralateral flaps raised without ischemia were used as controls. The survival of ischemic flaps in these groups at 7 days was 69 and 0%, respectively. After 6.5 hr of ischemia, microvascular blood flow in the ischemic flap was approximately 20% below that in the control flap for the first 3-4 days postoperatively, presumably reflecting ischemic damage to parts of the cutaneous microcirculation; thereafter, flow was not significantly different from controls up to 7 days postoperatively. Failed 6.5-hr ischemic flaps had initial sluggish blood flow which slowed to zero usually within 4 days postoperatively. After 17.5 hr ischemia, negligible microvascular flow was detectable postoperatively. Failure in the microcirculation as detected by the flowmeter occurred well in advance of any noticeable physical changes in the flap. It is concluded that the percentage ischemic flap flow of control flap flow for each animal (at any selected time up to 24 hr after revascularization) reliably predicts the viability of the flap after 7 days.