External hemipelvectomy for treatment of pelvic sarcomas resulted in a great loss of substance, which determined the exposure of pelvic organs such as bladder and rectum, the iliac neurovascular bundle, the hemisacrum and peritoneal contents. Reconstruction is challenging and patient tailor-made. Several flaps were described to cover external hemipelvectomies.
The gluteus maximus musculocutaneous flap, usually utilized for the treatment of decubitus, was well described by Becker1 and Dirnberger2 and many other authors. It is vascularized from the inferior gluteal artery and many variations of this flap were possible. In our case, it was excluded because left gluteal arteries were compromised from previous radiotherapy and gluteus muscle was invaded by the tumor. Anyway, even if gluteal musculature was healthy, it would not be enough to cover the expected loss of substance.
The rectus abdominus musculocutaneous flap was anatomically described in 1988 by Moon and Taylor3. It is a well- vascularized versatile pedicled flap based on the deep inferior epigastric vessels and it is able to cover large pelvic loss of substance. The ipsilateral flap could be associated to high complication rate due to dissection, which took place in the immediate vicinity of the deep inferior epigastric pedicle. Therefore, it could be safer using a flap based on the contralateral pedicle4. Unfortunately, in our patient abdominal wall was contaminated by the tumor; thus, it would not be an oncological safe reconstructive choice. Moreover, the patient was colostomized before the surgery.
The anterior myocutaneous flap of quadriceps femoris muscle5, generally indicated for buttock tumors, was excluded because the malignancy extended anteriorly in the pelvic cavity with involvement of the external and internal iliac vessels. As a matter of fact, we used the common iliac vessels to perform the anastomosis. For the same reason, a discontinuous myocutaneous quadriceps flap supplied by the superficial femoral artery6 was not indicated.
Although more favorable due to the absence of ischemic time and for shorter operating time, a pedicled flap were not suitable for our patient. Therefore, we decided to perform a free tissue transfer.
The type of surgery we offered the patient was a palliative surgery, strongly desired by himself and his family in order to make the last period of life free from pain, bleeding, odor and facilitating nursing care. Therefore, the lack of donor site morbidities and rapid recovery from surgery was crucial in front of a surgical palliation.
Latissimus dorsi free flap represented the main solution to reconstruct large loss of substance after hemipelvectomy. However, it would have resulted in shoulder girdle instability, compromising patient's balance and his residual quality of life.
Once all traditional possibilities have been explored, the spare parts surgery was the only one which fulfilled oncological and palliative goals.
"Spare parts" concept involved the use of composite tissues from the amputated limb to reconstruct complex defects originated from tumors or trauma.7
The Popliteal- based filleted lower leg musculocutaneous free-flap was described for the first time by Workman et al. in 19918. A free fillet flap from the amputated limb maintained the possibility of LD free flap as second chance in case of failure.
One of the principal problems of this flap was the prolonged ischemic time. Few solutions were described in medical literature, due to the small number of patients who needed this kind of surgery.
Yamamoto et al. 9,10 harvested the flap after the extensive resection of the tumor, just before ligating the vessels and removing the limb and they immediately cooled the fillet flap with crushed ice. Thus, the time of ischemia of the flap, which was minimized from icing the flap, coincided with the iliac vessels preparation for anastomosis.
In our experience, the clinical condition and the extension of malignancy have resulted in the need for a simultaneous approach between orthopedics, general surgeons and plastic surgeons. In particular, tumor involved bladder, urinary tract including left kidney and enveloped the iliac external and internal vessels. Therefore, it was not possible to ligate the iliac vessels at the end of the oncological resection. Once the vessels were ligated, the abdominal surgery had to be completed and this would have resulted in a time of flap's ischemia not compatible with its survival, even if cooled with ice.
Bibbo et al.11 suggested to start the surgery with the fillet flap dissection, leaving the flap attached to the proximal popliteal vascular pedicle and the Achilles tendon. In this way, they allowed the fillet flap perfusion during oncologic resection. They reported an ischemic time less than 45 minutes, time needed for preparation of vascular pedicle.
This method was not usable in our case too; either for the need of early ligation of iliac vessels, or for the necessity to frequently rotate the patient on the operating table in order to reach the malignancy in every parts. This would have entailed dangerous stresses on the vascular pedicle, risking to create damage. Moreover, our patient had zero negative blood type. The flap perfusion during dissection would have increased blood loss, enhancing the demand of transfusion for a blood type not available in large quantities.
Finally, Boehmler et al.12 described a two-stage fillet flap in order to decrease ischemic time and to allow patient resuscitation between the two stage. We preferred to avoid two surgeries, given the clinical frailty of our patient and the need for complex and simultaneously cooperation of three different teams.
Furthermore, some authors preferred to harvest the flap preserving the fibula in order to save time and to not risk to damage the flap vascular bundle12–14. Contrary, we decided to make a subperiosteal dissection, removing completely the fibula. In our opinion, leaving the fibula inside the flap could determine a risk of decubitus that is higher than the potential benefits.
In light of all these issues, the first and senior authors devised a new strategy never described before. As used in transplant surgery, we decided to connect the flap to the ECMO system by circulating 2 units of blood red cells and saline solution. This strategy allowed to save the time it took to finish abdominal oncological resection after vessels ligation and lastly the osteotomy of the sacrum. The difficulty encountered by the hemodynamics’ technician was that the free flap consisted of an open circuit due to the dispersion of terminal collateral arteries. Consequently, pump pressure set on the machine was hardly supported. The problem was solved infusing saline solution continuously into the circuit and making adequate hemostasis simultaneously on the periphery of the flap. Moreover, the flap was closed in on itself in order to reduce loss of circulating volume.
The perfusion lasted above 60 minutes and was successful. At the end the flap was rosy and vital with a good refill time.