Recommendations for contrast enhanced ultrasound (CEUS) in free tissue transplant monitoring

Application of flow-through flaps for replantation after traumatic limb amputation according to the angiosome concept

OBJECTIVE

This study was performed to explore the treatment of the injury caused by traumatic limb amputation.

METHODS

From October 2002 to October 2021, 30 cases were enrolled in the present study. The reasons for injury were as follows: 8 cases with single hydraulic column crush injury, 12 cases with gear and wire rope stranding, 6 cases with belt avulsion injury, and 4 cases with carbon block smash injury. The present study application of a free or small saphenous vein bypass to reconstruct the injured artery and vein according to the concept of the angiosome model. The defective vessels were bridged with the axial vessels of a flow-through flap, such as a medial calf flap or anterolateral femoral flap, to construct an additional blood supply and drainage vein for the severed limb. The clinical data of 30 cases with traumatic limb amputation of the lower leg and ankle were retrospectively analyzed.

RESULTS

In all 30 cases of traumatic limb amputation, the replantation via the adoption of a flow-through flap was successful, and 85.6% of the patients remained in good postoperative condition. There were no symptoms of ischemia in the marginal segment after blood supply reconstruction of the transected limb by axial vascular bridging within the flap.

CONCLUSION

Via the adoption of microsurgical techniques, the blood supply to the transected limb can be reconstructed by bridging the defective vessels with the adoption of the axial vessels of the flow-through flap is a feasible and advanced treatment option.

The value of sonographic microvascular imaging in the diagnosis of lipedema

BACKGROUND

Lipedema is a chronic disease marked by symmetric enlargement of painful nodular and fibrotic adipose tissue, predominantly affecting the limbs. Since there is no specific test or biomarker for this condition, years often pass before the diagnosis of lipedema is established for the first time, thereby causing psychosocial distress, including depression, eating disorders, and social isolation. Over the last few years several advanced Doppler-based technologies have been developed to visualize slow flow blood vessels and superficial microvascular architecture undetectable by traditional color Doppler flow imaging (CDFI).

OBJECTIVE

The aim of this study was to evaluate the superficial microvascular anatomy in lipedema patients compared to healthy controls and investigate the clinical significance of the Ultra Micro Angiography (UMA) technology in the diagnosis of lipedema. This new technique may contribute to reduce the diagnostic delay and, eventually, establish and guide treatment strategies toward a better therapeutic outcome in lipedema patients.

METHODS

25 patients with lipedema and ten healthy controls with no history of lipedema were included in this study. All ultrasound examinations were performed on a novel high-performance ultrasound system (Resona R9/Mindray) using CDFI and the UMA technique.

RESULTS

In all of the patients, Ultra Micro Angiography achieved the excellent visualization of microvascular structures, revealing that most lipedema patients showed grade 3 (n = 13) or grade 2 (n = 8) flow. UMA was superior to CDFI for depicting the microvascular structures.

CONCLUSIONS

Here we show that UMA imaging characterizes the subcutaneous microvasculature with an unprecedented accuracy. The method has the advantage of being sensitive to small, slow-flowing vessels. This allows for the assessment of the course of vessels and vascular pathologies in great detail. Thus, UMA as a non-invasive diagnostic method can improve diagnostic accuracy in lipedema.

The perfusion index as a noninvasive method for monitoring revascularized and replanted digits

BACKGROUND

Monitoring replanted digits remains a challenging task in microsurgical units. Previous studies have indicated the perfusion index (PI), a parameter directly proportional to the blood flow, might be a useful tool.

OBJECTIVE

The PI is evaluated as a monitoring tool in patients with replanted digits.

METHODS

This prospective, non-interventional study includes 31 patients with revascularized or replanted digits. After successful revascularization or replantation, the PI and peripheral oxygen saturation of the affected finger and its contralateral equivalent were measured simultaneously. The values were detected by the device Radical-97® Pulse CO-Oximeter® (Masimo Corporation, 52 Discovery, Irvine, CA 92618, USA).

RESULTS

The median PI of affected fingers was 3.5±0.56 for revascularized and 2.2±0.8 for replanted fingers. The difference between the PI values of replanted digits and the healthy contralateral side was highly significant (p < 0.0001). The area under the curve in the receiver operating characteristics was 0.92 for a PI difference > 80.49% and predicted a loss of replant with a specificity of 100% and a sensitivity of 75%.

CONCLUSION

The assessment of the PI in patients with reperfusion of a vascular compromised digit is a useful tool to continuously monitor peripheral perfusion. The dynamic behavior of the PI is essential to detect perfusion disturbance.

[Vascular diagnostics before microvascular tissue transfer on the lower extremities : An algorithm]

Microsurgical free flap transfer plays a key role in soft tissue reconstruction of the lower extremities. Through close cooperation between plastic and orthopedic surgery, great progress and success in limb salvage could be achieved over the last decades. The risk for extremity malperfusion is especially high in older patients and after trauma. To maximize the success rate for free flap transfer there is need for interdisciplinary clinical examination and diagnostics. In addition to clinical methods radiological procedures are necessary to evaluate and optimize lower extremity perfusion before surgery.Vascular ultrasound provides important information about the arterial and venous status; however, DSA, CTA and MRA are well-established and exact methods to evaluate arterial inflow. The use of less invasive methods makes it much more feasible, economic and comfortable to perform preoperative selection of patients requiring interventional procedures.In the case of intraluminal stenosis without any option for PTA, a vascular surgeon can be involved at an early stage to evaluate further surgical options. In some cases, similar surgical revascularization and free flap transfer can be performed in a single surgery. The aim of this study is to implement a standardized algorithm for preoperative examination and radiological diagnostics before reconstructive surgery of the lower extremity.

[Application of contrast-enhanced ultrasound-assisted superficial inferior epigastric artery perforator flap to repair oral and maxillofacial defects]

Objective

To investigate the application value of contrast-enhanced ultrasound (CEUS) technique to assist the repair of oral and maxillofacial defects by superficial inferior epigastric artery perforator flap.

Methods

Sixteen oral cancer patients, 10 males and 6 females, who were to undergo superficial inferior epigastric artery perforator flap repair between June 2018 and February 2020, were selected, with an average age of 55.8 years (range, 24-77 years). There were 13 cases of squamous cell carcinoma, 2 cases of adenoid cystic carcinoma, and 1 case of mucinous epidermis-like carcinoma. The color Doppler ultrasound (CDUS) and CEUS were used to screen the superficial inferior epigastric artery, assisted in the design of the flap, and compared it with the actual intraoperative exploration. The sensitivity, specificity, positive predictive value, and negative predictive value of CEUS and CDUS examinations were analyzed. Fourteen of 16 patients were repaired with superficial inferior epigastric artery perforator flap, and 2 patients were repaired with superficial iliac artery flap because the source artery was not found. After surgery, regular follow-up was performed to check for disease recurrence and metastasis and to evaluate the appearance of the patien's donor area, the recovery of transoral feeding function, and the presence of complications.

Results

Comparison of preoperative CDUS and CEUS findings and intraoperative exploration showed that CEUS had 100% sensitivity, specificity, positive predictive value, and negative predictive value for vascular exploration of the superficial inferior epigastric artery perforator flap, compared with 57%, 100%, 100%, and 25% for CDUS. The preoperative CDUS identified 25 penetrating vessels in 14 cases repaired with superficial inferior epigastric artery flaps. All vessel signals were enhanced by CEUS enhancement, and an additional 11 penetrating vessels were identified confirmed intraoperatively. The preoperative CEUS measurements of the initial diameter of superficial arteries in the abdominal wall were significantly higher than both CDUS and intraoperative measurements ( P<0.05); the difference in peak systolic velocity between CEUS and CDUS measurements was significant ( t=3.708, P=0.003). One case of superficial epigastric artery perforator flap developed venous embolism crisis at 48 hours after operation, the wound healing delayed. The other incisions in donor sites healed by first intention. All the patients were followed up 3-12 months, with an average of 8 months. No recurrence or metastasis appeared during the follow-up. There was no serious complications such as abdominal wall hernia, the location of abdominal scarring was hidden, and transoral feeding was resumed.

Conclusion

The superficial inferior epigastric artery perforator flap with small injury in supply area and hidden scar location is a better choice for repairing oral and maxillofacial defects. The use of CEUS technique to assist the preoperative design of the superficial inferior epigastric artery perforator flap has good feasibility and high accuracy.

Enhanced Resorption of Liposomal Packed Vitamin C Monitored by Ultrasound

Vitamin C is an essential nutrient for humans and is involved in a plethora of health-related functions. Several studies have shown a connection between vitamin C intake and an improved resistance to infections that involves the immune system. However, the body cannot store vitamin C and both the elevated oral intake, and the intravenous application have certain disadvantages. In this study, we wanted to show a new formulation for the liposomal packaging of vitamin C. Using freeze etching electron microscopy, we show the formed liposomes. With a novel approach of post-processing procedures of real-time sonography that combines enhancement effects by contrast-like ultrasound with a transducer, we wanted to demonstrate the elevated intestinal vitamin C resorption on four participants. With the method presented in this study, it is possible to make use of the liposomal packaging of vitamin C with simple household materials and equipment for intake elevation. For the first time, we show the enhanced resorption of ingested liposomes using microbubble enhanced ultrasound imaging.

Investigation of the acute plantar fasciitis with contrast-enhanced ultrasound and shear wave elastography - first results

BACKGROUND

The plantar fasciitis is a common disease with a high prevalence in public and a frequent cause of heel pain.

OBJECTIVE

In our pilot study, we wanted to characterise the feasibility of shear-wave elastography and contrast-enhanced ultrasound (CEUS) in the assessment of the plantar fasciitis.

METHODS

23 cases of painful heels were examined by B-Mode ultrasound, Power Doppler (PD), shear wave elastography and contrast-enhanced ultrasound before anti-inflammatory radiation. Time-intensity-curves were analysed by the integrated software. The results for area-under-the-curve (AUC), peak, time-to-peak (TTP) and mean-transit-time (MTT) were compared between the plantar fascia and the surrounding tissue.

RESULTS

All cases showed thickening of the plantar fascia, in most cases with interstitial oedema (87.0%). Shear wave elastography showed inhomogeneous stiffness of the plantar fascia. 83.3% of cases showed a visible hyperperfusion in CEUS at the proximal plantar fascia in comparison to the surrounding tissue. This hyperperfusion could also be found in 75.0% of cases with no signs of vascularisation in PD. AUC (p = 0.0005) and peak (p = 0.037) were significantely higher in the plantar fascia than in the surrounding tissue.

CONCLUSION

CEUS and shear wave elastography are new diagnostic tools in the assessment of plantar fasciitis and can provide quantitative parameters for monitoring therapy.