Hyperthermic Isolated Limb Perfusion with TNF alpha and Cisplatin in the Treatment of Osteosarcoma of the Extremities: A Feasibility Study in Healthy Dogs

Development of an Extracorporeal Perfusion Device for Small Animal Free Flaps

Background

Extracorporeal perfusion (ECP) might prolong the vital storage capabilities of composite free flaps, potentially opening a wide range of clinical applications. Aim of the study was the development a validated low-cost extracorporeal perfusion model for further research in small animal free flaps.

Methods

After establishing optimal perfusion settings, a specially designed extracorporeal perfusion system was evaluated during 8-hour perfusion of rat epigastric flaps followed by microvascular free flap transfer. Controls comprised sham-operation, ischemia and in vivo perfusion. Flaps and perfusate (diluted blood) were closely monitored by blood gas analysis, combined laser Doppler flowmetry and remission spectroscopy and Indocyanine-Green angiography. Evaluations were complemented by assessment of necrotic area and light microscopy at day 7.

Results

ECP was established and maintained for 8 hours with constant potassium and pH levels. Subsequent flap transfer was successful. Notably, the rate of necrosis of extracorporeally perfused flaps (27%) was even lower than after in vivo perfusion (49%), although not statistically significant (P = 0,083). After sham-operation, only 6% of the total flap area became necrotic, while 8-hour ischemia led to total flap loss (98%). Angiographic and histological findings confirmed these observations.

Conclusions

Vital storage capabilities of microvascular flaps can be prolonged by temporary ECP. Our study provides important insights on the pathophysiological processes during extracorporeal tissue perfusion and provides a validated small animal perfusion model for further studies.

Hyperthermic isolated regional perfusion of the limb with carboplatin

AIMS

To investigate the feasibility of hyperthermic isolated regional perfusion (HIRP) with carboplatin in the management of locally recurrent and/or intransit metastases of melanoma or locally advanced soft tissue sarcoma.

METHODS

Three patients, two with locally advanced melanoma and one with a low-grade liposarcoma of the lower extremity, were treated with HIRP under mild hyperthermia (39-40 degrees C) with 125 mg carboplatin/l perfused limb volume.

RESULTS

No systemic toxicity was observed. Local toxicity consisted of post-perfusion oedema present in all three patients which resolved within 2 weeks. Clinically, a persistent local neuropathy was observed in all three patients, two of which were confirmed by electromyogram and nerve conduction study. Severe motor-sensory neuropathy was located mainly in the peroneal and sural nerves of the perfused limbs. Pharmacokinetic parameters of the carboplatin showed a higher concentration of carboplatin in the skin compared to the muscle. The two melanoma patients showed a complete response but developed local recurrences within 1.5 years after perfusion. The third patient underwent a delayed excision of the sarcoma 8 weeks after perfusion which revealed 50% viable tumour. One of the melanoma patients and the sarcoma patient died from lung metastases 56 and 31 months post-perfusion treatment, respectively. The other melanoma patient is alive 95+ months post-perfusion treatment.

CONCLUSIONS

The local neurotoxicity observed did not warrant further research of carboplatin in HIRP.