Determination of amputation level in ischaemic limbs using tcPO2 measurement

Salami-Tactics: when is it time for a major cut after multiple minor amputations?

INTRODUCTION

Repetitive minor amputations carry the concomitant risks of multiple surgical procedures, major amputations have physical and economical major drawbacks. The aim of this study was to evaluate whether there is a distinct number of minor amputations predicting a major amputation in the same leg and to determine risk factors for major amputation in multiple minor amputations.

MATERIALS AND METHODS

A retrospective chart review including 429 patients with 534 index minor amputations between 07/1984 and 06/2019 was conducted. Patient demographics and clinical data including number and level of re-amputations were extracted from medical records and statistically analyzed.

RESULTS

290 legs (54.3%) had one or multiple re-amputations after index minor amputation. 89 (16.7%) legs needed major amputation during follow up. Major amputation was performed at a mean of 32.5 (range 0 - 275.2) months after index minor amputation. No particular re-amputation demonstrated statistically significant elevated odds ratio (a.) to be a major amputation compared to the preceding amputation and (b.) to lead to a major amputation at any point during follow up. Stepwise multivariate Cox regression analysis revealed minor re-amputation within 90 days (HR 3.8, 95% CI 2.0-7.3, p <0.001) as the only risk factor for major amputation if at least one re-amputation had to be performed.

CONCLUSIONS

There is no distinct number of prior minor amputations in one leg that would justify a major amputation on its own. If a re-amputation has to be done, the timepoint needs to be considered as re-amputations within 90 days carry a fourfold risk for major amputation.

LEVEL OF EVIDENCE

Retrospective comparative study (Level III).

Transcutaneous Partial Pressure of Oxygen Measurement in Advanced Chronic Venous Insufficiency as a Marker of Tissue Oxygenation

Purpose

Determination of oxygen concentration in tissues affected by chronic venous insufficiency (CVI) has shown inconsistent results over the years and has confounded the pathophysiology of venous diseases. This study measured transcutaneous partial oxygen pressure (TcPO₂) levels in patients with CVI to assess oxygenation and variation in oxygenation according to CVI stage.

Methods

Materials and A prospective study was performed on consecutive patients with unilateral CVI. TcPO₂ of diseased and unaffected limbs was measured in the supine and dependent positions. A single TcPO₂ value was measured at the site of greatest skin change or at the edge of the ulcer. The TcPO₂ values were analyzed and compared according to stage.

Results

A total of 96 patients were included in the study with C4 (24.0%), C5 (19.8%), and C6 (56.3%) disease. The mean age was 44.7 years, and 85 (88.5%) were male. There was a statistically significant (P<0.01) difference in mean TcPO₂ levels between the unaffected limb (supine, 32.1 mmHg; dependent, 50.7 mmHg), C5 diseased limb (supine, 16.6 mmHg; dependent, 35.5 mmHg), and C6 diseased limb (supine, 24.2 mmHg; dependent, 40.4 mmHg). In the supine and dependent positions, the mean TcPO₂ in the affected limb was significantly lower (P<0.01) than that in the unaffected limb.

Conclusion

TcPO₂ in advanced CVI can be used as a marker of oxygenation status. This is the first study in an Indian population looking at the relevance of TcPO₂ in the prognostication of advanced CVI.

Milestones in thromboangiitis obliterans. A position paper of the VAS-European Independent Foundation in Angiology/Vascular Medicine

BACKGROUND

Unfortunately, even today Thromboangiitis Obliterans has disease features that remain misunderstood or underappreciated. The epidemiology, etiology and pathophysiology of the disease are still unclear. Biomarkers and disease activity markers are lacking, thus clinical assessment is difficult. We are still struggling to establish unique diagnostic, staging and treatment criteria. This is an academic-collaborative effort to describe the pathophysiology, the clinical manifestations, the diagnostic approach, and the challenges of management of patients with TAO.

METHODS

A systematic search for relevant studies dating from 1900 to the end of 2020 was performed on the PubMed, SCOPUS, and Science Direct databases.

RESULTS

Given the intriguing nature of presentation of TAO, its management, to some extent is not only different in different regions of the world but also varies within the same region. Following this project, we discovered ambiguity, overlap and lack of clear-cut criteria for management of TAO.

CONCLUSIONS AND RELEVANCE

An international group of experts however came to one conclusion. They all agree that management of TAO is in need of a call for action for a renewed global look with multi-center studies, to update the geographical distribution of the disease and to establish a unique set of diagnostic criteria and a consensus-based guideline for best treatment based on current evidence.

Resting TcPO2 levels decrease during liner wear in persons with a transtibial amputation

Background

In our clinic, a substantial number of patients present with transtibial residual limb pain of no specific somatic origin. Silicone liner induced tissue compression may reduce blood flow, possibly causing residual limb pain. Thus, as a first step we investigated if the liner itself has an effect on transcutaneous oxygen pressure (TcPO2).

Methods

Persons with unilateral transtibial amputation and residual limb pain of unknown origin were included. Medical history, including residual limb pain, was recorded, and the SF-36 administered. Resting TcPO2 levels were measured in the supine position and without a liner at 0, 10, 20 and 30 minutes using two sensors: one placed in the Transverse plane over the tip of the Tibia End (= TTE), the other placed in the Sagittal plane, distally over the Peroneal Compartment (= SPC). Measurements were repeated with specially prepared liners avoiding additional pressure due to sensor placement. Statistical analyses were performed using SPSS.

Results

Twenty persons (9 women, 11 men) with a mean age of 68.65 years (range 47–86 years) participated. The transtibial amputation occurred on average 43 months prior to study entry (range 3–119 months). With liner wear, both sensors measured TcPO2 levels that were significantly lower than those measured without a liner (TTE: p < 0.001; SPC: p = 0.002) after 10, 20 and 30 minutes. No significant differences were found between TcPO2 levels over time between the sensors. There were no significant associations between TcPO2 levels and pain, smoking status, age, duration of daily liner use, mobility level, and revision history.

Conclusion

Resting TcPO2 levels decreased significantly while wearing a liner alone, without a prosthetic socket. Further studies are required to investigate the effect of liner wear on exercise TcPO2 levels.

Involvement of microcirculation in critical ischemia: how to identify it?

Critical limb ischemia represents the most severe pattern of peripheral arterial disease (PAD) associated with the high risk of major amputation, cardiovascular events and death. The diagnosis and management of critical limb ischemia (CLI) is often challenging. Systolic ankle and toe pressure measurements are considered to be the basic techniques for the identification of PAD. However, they provide rough insight into the dependent local tissue perfusion. Furthermore, those techniques do not enable investigation of microcirculation which has crucial role in the pathogenesis of CLI. Some patients with mild deterioration of macrocirculation develop CLI if microcirculation is affected. Investigation of perfusion on macro- and local microcirculatory level enables more effective treatment: revascularization of the angiosome-related artery. The technologies capable of assessing limb tissue oxygenation or perfusion on microcirculatory level enable direct assessment of distant tissue oxygenation. Transcutaneous oxygen tension (TcPO2) measurement which was introduced in clinical practice represents one of the objective criteria for the diagnosis of CLI. Main weakness of this technique as well as laser Doppler flow measurement is low penetrance from the skin surface. Measurement of tissue blood flow on microcirculatory level can be performed with indocyanine green fluorescent imaging (ICG), contrast-enhanced magnetic resonance and vital microscopy. ICG is promising method which provides excellent informative image of tissue perfusion. However, it offers little quantitative information. Investigation of microcirculation in patients with CLI is of outmost importance because it enables insight in local tissue perfusion and oxygenation, which represents the basis of identification of most ischemic regions and provide more successful angiosome related revascularization of an affected artery.

Microcirculatory assessment of vascular diseases

The term "microcirculation" refers to the terminal vascular network of the body, which includes arterioles, capillaries, venules as well as initial lymphatic vessels. Additionally, it insinuates to their unique function in thermoregulation, fluid balance, maintenance of cellular exchange, and metabolism. Disturbances of microvascular function were identified to precede macrovascular involvement in the presence of cardiovascular risk factors and is the hallmark of terminal disease stages like critical limb or acral ischemia. Nevertheless, despite its obvious significance in vascular medicine assessment of microvascular function became increasingly neglected in the clinical institutions during the last decades and seems to play a subordinary role in medical education. We therefore provide an overview over relevant and clinically practicable methods to assess microcirculation in vascular medicine with critical estimations of their pros and cons and their perspectives in the future.

Predictors for reoperation after lower limb amputation in patients with peripheral arterial disease

Background: Major amputations in patients with peripheral arterial disease (PAD) carry a high risk for complications, including revision of the amputation, sometimes to a higher level. Determining a safe level for amputation with good wound healing potential depends largely on vascular measurements. This study evaluated potential predictive factors for revision of major lower extremity amputations in patients with PAD. Patients and methods: A retrospective chart review of all major lower extremity amputations at our institution was conducted. Amputations due to trauma or tumor and below-ankle amputations were excluded. Patient demographics, level/type of amputation, level/time of revision, comorbidities and risk factors were extracted. Results: 180 patients with PAD, mean age 66.48 (range: 31-93) years, 125 (69.4%) male were included. Most (154/180, 86.6%) underwent below-knee amputation. 71 (39.4%) patients had coronary arterial disease, 104 (57.8%) had diabetes. More than half of patients, (93/138; 51.7%) had undergone previous balloon angioplasty. 44 (30%) patients required revision surgery: 42/180 (23.3%) were revised at the same level, and in 12/180 (6.7%) a more proximal amputation was necessary. PAD stage was not associated with the level of reamputation (p = 0.4369). Significantly more patients who had previous balloon angioplasty required revision surgery (66.7% versus 45.2%, p = 0.009). 67 (37.2%) patients underwent preoperative TcPO2 measurement: 40/67 (59.7%) had TcPO2 ≥ 40 mmHg; 4/67 (6%) had TcPO2 < 10 mmHG. Three patients with TcPO2 ≥ 40 mmHg, one with 30 mmHg ≤ TcPO2 ≤ 40 mmHg and one with 10 mmHg ≤ TcPO2 ≤ 20 mmHg required re-amputation to a more proximal level. Conclusions: TcPO2 measurements are useful for determining level of lower limb amputation and predicting wound healing problems when an amputation level with TcPO2 < 40 mmHg is chosen. In transtibial amputations, TcPO2 ≥ 40 mmHg does not safely predict wound healing.

Outcome After Surgical Treatment of Calcaneal Osteomyelitis

BACKGROUND

Surgical procedures for calcaneal osteomyelitis are partial calcanectomy (PC), total calcanectomy (TC), and below-knee amputation (BKA). With calcaneal osteomyelitis, limb-saving surgery was described to have secondary BKA rates of 4% to 20%, while secondary amputation rates after BKA are unknown. The aim of this study was to describe and compare overall revision and secondary amputation rates for each surgical option in our institution's cohort and to identify risk factors for secondary amputation.

METHODS

Fifty patients treated between 2002 and 2017 were included. Revisions, secondary amputations, and possible risk factors for secondary amputation and overall revision were statistically analyzed.

RESULTS

Minor revisions rates were 57.1% in PCs, 100% in TCs, and 27.8% in BKAs. Secondary amputation was performed in 28.6% of the PCs, in 50% of the TCs, and in 5.6% of the BKAs. No statistically significant differences between overall revision and secondary amputation rates were found. C-reactive protein values greater than 5 mg/L at the index procedure were significantly associated with overall revision while we could not identify risk factors for secondary amputation.

CONCLUSION

This study represents the largest group of patients treated for calcaneal osteomyelitis in the literature. In limb-preserving surgical options, secondary BKA rates are higher than previously known. Primary BKA is a procedure with a low reamputation rate of 5.6%. PC can be considered, with 28.6% needing more proximal amputation. In TC, all patients underwent revision surgery and 50% had to undergo secondary BKA. Therefore, we hesitate to consider total calcanectomy as a surgical option in calcaneal osteomyelitis anymore.

LEVEL OF EVIDENCE

Level IV, case series.

Efficacy of Cellular Therapy for Diabetic Foot Ulcer: A Meta-Analysis of Randomized Controlled Clinical Trials

Diabetes mellitus is a widely spread chronic disease with growing incidence worldwide, and diabetic foot ulcer is one of the most serious complications of diabetes. Cellular therapy has shown promise in the management of diabetic foot ulcer in many preclinical experiments and clinical researches. Here, we performed a meta-analysis to evaluate the efficacy and safety of cellular therapy in the management of diabetic foot ulcer. We systematically searched PubMed, MEDLINE, EMBASE, and Cochrane Library databases from inception to May 2017 for randomized controlled trials assessing the efficacy of cellular therapy in diabetic foot ulcer, and a meta-analysis was conducted. A total of 6 randomized controlled clinical trials involving 241 individuals were included in this meta-analysis. The results suggested that cellular therapy could help accelerating the healing of diabetic foot ulcer, presented as higher ankle-brachial index (mean difference = 0.17, 95% confidence interval [CI] = 0.11 to 0.23), higher transcutaneous oxygen pressure (standardized mean difference [SMD] = 1.43; 95% CI, 1.09– to 1.78), higher ulcer healing rate (relative risk [RR] = 1.78; 95% CI, 1.41 to 2.25), higher amputation-free survival (RR = 1.25; 95% CI, 1.11 to 1.40), and lower scale of pain (SMD = −1.69; 95% CI, −2.05 to −1.33). Furthermore, cellular therapy seemed to be safe, with no serious complications and low risk of short-term slight complications. Cellular therapy could accelerate the rate of diabetic foot ulcer healing and may be more efficient than standard therapy for diabetic foot treatment.

Letter Regarding "The Prostacyclin Analogue Iloprost as an Early Predictor of Successful Revascularization in Diabetic Patients Affected by Critical Limb Ischemia and Foot Ulcers"

PURPOSE

The aim of this study is to evaluate the role of Iloprost as an early predictor of successful revascularization in patients affected by ischemic diabetic foot ulcers (DFUs).

METHODS

Consecutive patients with ischemic DFUs with persistent low TcPO2 (<30mmHg) one day after a technical successful Percutaneous Transluminal Angioplasty (PTA) have been included. All patients underwent Iloprost infusion and TcPO2 has been recorded at days 3, 14 and 30. According to the TcPO2 reported at day 3, patients were divided into two groups: group A (patients with TcPO2 ≥30mmHg) and group B (patients with TcPO2 <30mmHg). Baseline TcPO2 values at days 3, 14 and 30 after Iloprost infusion and needing of re-intervention (re-PTA) have been evaluated.

RESULTS

Twenty-five patients have been included, 12/25 (48%) in Group A and 13/25 (52%) in Group B. There were no significant differences at the baseline and one day after PTA between the two groups while TcPO2 values recorded in Group A at days 3, 14 and 30 after Iloprost infusion were significant higher in comparison to the Group B (χ = 0.005). The rate of re-PTA were respectively 33,3% (Group A) and 53,8% (Group B) (p = 0.03).

CONCLUSIONS

Iloprost may be an early predictor of successful revascularization in patients affected by critical limb ischemia (CLI) and DFUs.

Rearfoot Transcutaneous Oximetry is a Useful Tool to Highlight Ischemia of the Heel

PURPOSE

To demonstrate the usefulness of rearfoot transcutaneous oximetry to assess the peripheral arterial disease in diabetic patients with heel ulcer.

METHODS

From our database of 550 critical limb ischemia diabetic patients followed after a percutaneous transluminal angioplasty, we have selected patients with below the knee arterial disease. Patients were grouped according to the dorsal transcutaneous oximetry value (Group A < 30 mmHg; Group B ≥ 30 mmHg). Patients of Group B had a second oximetry performed at the rearfoot, close to the lesion localized in all cases at the heel. Finally, the analysis of the arterial pattern disease has been done.

RESULTS

We selected 191 patients: Group A (151 patients), dorsal transcutaneous oximetry of 11.8 ± 0.7 mmHg; Group B (40 patients), dorsal transcutaneous oximetry of 44.2 ± 10.1 mmHg. In Group B, rearfoot oximetry was 20.5 ± 5 mmHg, significantly lower than dorsal oximetry (p = 0.0179). The anterior tibial artery was involved in all patients of Group A. In Group B, the anterior tibial artery was involved in 15 subjects and never alone; the posterior tibial artery was involved in 20 subjects and in 11 cases alone. The peroneal artery was affected in 20 subjects and in 14 patients alone.

CONCLUSION

When a heel lesion is present and the transcutaneous oximetry recorded on the dorsum of the foot does not confirm the presence of critical limb ischemia (not ≤30 mmHg), a second oximetry recorded on the rearfoot is useful to point out ischemia of the peroneal artery and/or of the posterior tibial artery.

REVIEW: HEMODYNAMIC STUDIES FOR LOWER LIMB AMPUTATION AND REHABILITATION

No matter what the reason and level of amputation are, amputees will face many complex postoperative problems and potential complications. From the perioperative stage to lengthy rehabilitation process, patients need comprehensive and cautious therapies to help them rebuild their physical and mental health. Although there is some scattered information, the achievements of hemodynamic study for lower limb amputation and rehabilitation have not been systematically classified and summarized. The purpose of this review is to introduce and discuss the hemodynamic issues in preoperative diagnosis, surgical techniques and postoperative problems in the past two decades. Whether from clinical or biomechanical perspective, the investigations of the former two stages have been relatively mature and gained some clear outcomes, even if some conclusions are conflicting and controversial. While in terms of the postoperative problems, such as the common pressure ulcers, DTI and muscle atrophy, there is a lack of vascular or blood flow state studies specifically for lower residual limb. Therefore, the future research focus of hemodynamics for lower limb amputation should probably be the detailed investigations on the relationships between various blood flow parameters and certain common complications. Although hemodynamic research has made some achievements at this stage, it is believed that more advanced and reliable techniques are pending for further explorations and developments.

A novel, non-invasive diagnostic clinical procedure for the determination of an oxygenation status of chronic lower leg ulcers using peri-ulceral transcutaneous oxygen partial pressure measurements: results of its application in chronic venous insufficiency (CVI)

The basis for the new procedure is the simultaneous transcutaneous measurement of the peri-ulceral oxygen partial pressure (tcPO₂), using a minimum of 4 electrodes which are placed as close to the wound margin as possible, additionally, as a challenge the patient inhales pure oxygen for approximately 15 minutes.

In order to evaluate the measurement data and to characterise the wounds, two new oxygen parameters were defined: (1) the oxygen characteristic (K-PO₂), and (2) the oxygen inhomogeneity (I-PO₂) of a chronic wound. The first of these is the arithmetic mean of the two lowest tcPO₂ measurement values, and the second is the variation coefficient of the four measurement values. Using the K-PO₂ parameter, a grading of wound hypoxia can be obtained. To begin with, the physiologically regulated (and still compensated) hypoxia with K-PO₂ values of between 35 and 40 mmHg is distinguished from the pathological decompensated hypoxia with K-PO₂ values of between 0 and 35 mmHg; the first of these still stimulates self-healing (within the limits of the oxygen balance). The decompensated hypoxia can be (arbitrarily) divided into “simple” hypoxia (Grade I), intense hypoxia (Grade II) and extreme hypoxia (Grade III), with the possibility of intermediate grades (I/II and II/III).

Measurements were carried out using the new procedure on the skin of the right inner ankle of 21 healthy volunteers of various ages, and in 17 CVI (chronic venous insufficiency) wounds. Sixteen of the 17 CVI wounds (i.e., 94%) were found to be pathologically hypoxic, a state which was not found in any of the healthy volunteers. The oxygen inhomogeneity (I-PO₂) of the individual chronic wounds increased exponentially as a function of the hypoxia grading (K-PO₂), with a 10-fold increase with extreme hypoxia in contrast to a constant value of approximately 14% in the healthy volunteers. This pronounced oxygen inhomogeneity explains inhomogeneous wound healings, resulting in the so-called mosaic wounds. The hypoxia grades found in all of the chronic wounds was seen to be evenly distributed with values ranging from 0 to 40 mmHg, and therefore extremely inhomogeneous. In terms of oxygenation, chronic wounds are therefore inhomogeneous in two respects: (1) within the wound itself (intra-individual wound inhomogeneity) and (2) between different wounds (inter-individual wound inhomogeneity). Due to the extreme oxygen inhomogeneity, single measurements are not diagnostically useful.

In healthy individuals the oxygen inhalation challenge (see above) results in synchronised tcPO₂ oscillations occurring at minute rhythms, which are not seen in CVI wounds. These oscillations can be interpreted as a sign of a functioning arterial vasomotor system.

The new procedure is suitable for the routine characterisation of chronic wounds in terms of their oxygen status, and correspondingly, their metabolically determining (and limiting) potential for healing and regeneration. The oxygen characteristic K-PO₂ can furthermore be used as a warning of impending ulceration, since the oxygen provision worsens over time prior to the demise of the ulcerated tissue, thus making a controlled prophylaxis possible.

Effects of a single dose of terlipressin on transcutaneous oxygen pressures

OBJECTIVE

Terlipressin (TP) is a potent vasoconstrictor, which is widely used in the treatment of bleeding esophageal varices and the hepatorenal syndrome. Side effects to TP are often related to skin hypoxaemia. The aim of the study was to investigate the transcutaneous oxygen pressures (TcPO(2) mmHg) after administration of 2 mg of TP.

PATIENTS AND METHODS

Nineteen patients with cirrhosis and ascites were included. TcPO(2) mmHg were measured continuously measured at the chest, abdominal wall and at the lower extremity at baseline and after 2 mg TP in 15 patients and placebo in 4 patients.

RESULTS

The mean whole body TcPO(2) decreased after TP by 34% (p < 0.005). The decrease was even more pronounced in the lower extremity: above knee -33% (50 vs. 33 mmHg, p = 0.01) and below knee -52% (52 vs. 26 mmHg, p = 0.001). Levels below 30 mmHg, were found in 60% of the patients after TP compared to 0% in the placebo group, p = 0.005. There were no significant changes in TcPO(2) after placebo. The baseline leg TcPO(2) correlated inversely with the MELD score (r = -0.64 and p < 0.003) and the increase in MAP after TP correlated inversely with TcPO(2) at the thorax (r = -0.60, p = 0.009).

CONCLUSIONS

Sixty percent of patients with decompensated cirrhosis develop hypoxaemia in the lower limb after one dose of TP.

Early postoperative detection of tissue necrosis in amputation stumps with indocyanine green fluorescence angiography

OBJECTIVE

Amputations of the lower extremity due to irreversible ischemic tissue loss are performed as distally as possible. Therefore, oftentimes wound-healing disorders develop, requiring additional surgical treatment.

METHODS

The amputations stumps of 10 patients with irreversible ischemic tissue loss due to arteriosclerosis were investigated within 72 hours postoperatively with indocyanine green (ICG) fluorescence.

RESULTS

For 6 of the investigated stumps, no perfusion deficit could be seen through fluorescence angiography. All stumps displayed primary healing. In the fluorescence angiography of 3 amputations, stump perfusions deficits predicted later tissue necrosis and had to be amputated again in a second operation. One amputation wound showed a small ICG perfusion deficit that represented a blood clot.

CONCLUSION

Indocyanine green fluorescence angiography allows a perfusion analysis of amputation stumps and therefore a prediction of the expected tissue necrosis. This tool may allow reliable prediction of amputation level.

Functional Results After Through-Knee and Above-Knee Amputations: Does More Length Mean Better Outcome?

The objective was to evaluate our results on functional outcome for both through-knee amputations and above-knee amputations. Functional outcome was measured using the Special Interest Group in Amputee Medicine score, which focuses on walking distance and use of prosthesis. From 1997 to 2006, 39 through-knee amputations (53%) and 34 above-knee amputations (47%) were performed. Eight (21%) of 39 through-knee amputations needed to be converted to above-knee amputations. Fifty patients (24 above-knee amputations, 26 through-knee amputations) were eligible for follow-up. During follow-up, 71% (of above-knee amputations) and 69% (of through-knee amputations) did not walk with a prosthesis, and 29% of above-knee amputations and 27% of through-knee amputations walked more or less than 50 m. In conclusion, only a minority of patients is able to walk with a prosthesis, and a lot of the through-knee amputations need conversion to a higher level. On the basis of this results, it would be preferable to perform a straight above-knee amputation instead of a through-knee amputation if the correct amputation level is in doubt in high-risk patients.

A review of the clinical significance of tissue hypoxia measurements in lower extremity wound management

The aim of this paper is to review techniques that are currently available to measure tissue hypoxia in order to benefit the management of wounds. Direct measurement of tissue partial oxygen pressure (PO(2)) is invasive and therefore unappealing in clinical practice. Several techniques (PET scans, MRI derived techniques) are primarily applicable to research rather than clinical applications. Imaging techniques (duplex ultrasonography, arteriography, MRI techniques) are recommended only as part of the workup for revascularisation. Techniques that assess local perfusion include clearance methods, transcutaneous O(2) and CO( 2) pressure measurement, and laser Doppler flowmetry and imaging. These techniques permit interpretation of altered perfusion states. Each technique offers subtly different information concerning microvascular function. All these techniques require strict protocols to derive reliable data. The potential of the promising near infrared reflectance spectroscopy (NIRS) technique is yet to be determined.

Predictive value of 99mTc-sestamibi scintigraphy for healing of extremity amputation

PURPOSE

Although various non-invasive procedures have been proposed to determine the optimal level of amputation of limbs in patients who have vascular disease, currently there are no consistent criteria that can be applied before surgery. The purpose of this study was to determine whether (99m)Tc-sestamibi imaging can accurately predict the healing of amputation sites.

METHODS

In a prospective study in 26 patients (21 men, 5 women; age range 23-94 years) presenting with ulcers or gangrene of the foot and hand, (99m)Tc-sestamibi imaging was performed preoperatively. The indications for amputation included gangrene (23 patients), electrical injury (2 patients) and trauma (1 patient) of extremities. Although the amputation levels were chosen according to clinical criteria and scintigraphic results, the final amputation level was defined by scintigraphic results. Two below-knee, one above-knee, 12 toe, 11 transmetatarsal, two phalanx, one finger and one thumb amputations and one shoulder disarticulation were performed. In four cases, the amputation defect was not suitable for coverage using a local dermal flap; rather, it was covered with free tissue transfer. Patients had clinical follow-up for 6-36 months (mean 11.69 months) to assess healing of the stump. Scan results were compared with clinical outcome to assess prediction of healing.

RESULTS

There was healing in all amputations at the end of the follow-up period. When evaluated regarding preoperative (99m)Tc-sestamibi uptake pattern, there was no perfusion to the lesion site in 21 patients and perfusion to an area smaller than the extent of skin necrosis in four patients; thus, in these 25 patients, (99m)Tc-sestamibi scintigraphy suggested non-viable tissue in the extremities with clear-cut edges of perfused muscle tissue. Diffusely decreased uptake was seen below the left knee in one case. How scintigraphy changed management was analysed. The amputation levels proposed before scintigraphy were divided into two groups, "definite" (n=14) and "indefinite" (n=12), based on visual examination and Doppler findings. In nine patients in the definite group, the proposed amputation level before scintigraphy was not altered by the scintigraphic data. However, (99m)Tc-sestamibi scan enabled unnecessarily high amputation levels to be avoided in 12 patients in the indefinite group and in five patients in the definite group. Therefore, there was change in management of 65% of cases based on scintigraphic findings.

CONCLUSION

Since healing of the stump was seen in all cases, outcome was correctly predicted by scintigraphy. This preliminary study supports the use of (99m)Tc-sestamibi scan in selecting the optimal amputation level consistent with subsequent stump healing.