Plastic and orthopaedic surgeons at Penn Medicine are performing vascularized tissue transfers using microsurgical robots to sew blood vessels during reconstruction of extremity injuries.
With the introduction of microsurgery, the prospects for post-traumatic extremity reconstruction advanced from standard microsurgical tissue transfer procedures to sophisticated perforator-to-perforator anastomosis of vessels smaller than 1.0 millimeters.
Despite its vast potential, traditional microsurgery has substantial limitations, particularly those imposed by intraoperative tremor (or quasi-periodic oscillation) of the surgeon’s hand. To an extent, tremor is unavoidable in surgery, and in classic open surgery is typically a negligible consideration. However, at the scale of microsurgery (vessels <1mm), even slight tremor can be an impediment to vessel manipulation and suturing.
To resolve intraoperative tremor, machines designed expressly for microsurgery are now available in the United States. Recently FDA-approved, these robots and their instrumentation reduce inherent motion tremor by capturing a surgeon’s hand movements in identical, scaled-down motion while maintaining the natural movement of the human wrist. Among the surgeries enhanced by this advance at the Penn Orthoplastic Limb Salvage Center are microsurgical free vascularized fibular grafts (FVFG), and free skin and muscle flaps.
Typical of microsurgical vascularized tissue transfers at Penn Medicine, FVFG has the purpose of replacing necrotic or absent bone wherever it occurs with viable, structurally sound, vascularized bone from a patient’s own fibula. Blood vessels are transferred with the fibular bone and grafted (anastomosed) to blood vessels at the recipient site. This process facilitates bone healing and reconstruction of the extremity.
Case Study
Mr. D, age 46 years, arrived at Penn Orthopaedics from Ukraine several months after a blast injury eradicated the proximal ulna and ulnar artery of his left forearm. Under the care of Drs. L. Scott Levin and Stephen Kovach, a microsurgical procedure was planned to transfer a vascularized fibular graft from the right leg to the left ulna, with nerve and soft-tissue reconstruction. This surgery involved the use of a microsurgical robot, which was used to complete the revascularization of the graft.
The Procedure: Following a series of standard safety and preparatory procedures in the operating room, a volar incision was made at the left forearm. Dissection was carried down to the intercalary malunion of the proximal ulna, and the ulnar artery and nerve were identified. A large neuroma was found under the flexor muscle of the forearm and this was resected. Further dissection and elevation of the skin flaps and skin graft over the soft tissue defect exposed the distal ulna, ulnar artery, and ulnar nerve. The latter was trimmed back to healthy fascicles, revealing a 12 cm ulnar nerve defect.
Site Preparation: The ulnar artery was deemed beyond salvage, and was dissected to the brachial artery proximally, with care to protect the median nerve. Following identification of the artery takeoff and dissection into the scarred region of the forearm, the ulnar artery was mobilized off the bifurcation at the brachial artery. During this time, cutaneous veins were identified as recipients for microvascular anastomosis, and the cephalic vein identified as a potential recipient for venous outflow of the flap. A microsurgical occlusion clamp was placed across the ulnar artery proximally in preparation for robotic microsurgical anastomosis.
Nerve Reconstruction: Under the operating microscope using 8-0 interrupted sutures and tissue glue, the ulnar nerve was reconstructed using the spliced 12 cm of nerve allograft.
Vascularized Fibular Graft: Following selective incisions and dissection at the lower right leg, a section of fibula with its artery and vein was harvested. The harvested fibular bone was transferred to the left forearm, and an intramedullary pin was passed through the distal ulna and the medullary canal of the fibula into the proximal ulna. The pin was supplemented with mini-plates proximately and distally to stabilize the living bone graft in the forearm and complete the stabilization between the two sections of bone.
As a result of the vascular deficiency of the fibular pedicle length, the vein of the radial artery (venae comitantes) were used to anastomose the ulnar artery proximally and distally to the peroneal artery. Given the small diameter of these vessels, this anastomosis was completed using the microsurgical robot (Figure 1).
Figure 1: Microsurgical robotic instruments complete fine vessel anastomosis in vascularized tissue transfer surgery.
After creating inflow, the cephalic vein was then anastomosed to a large draining vein from the fibula. Excellent outflow from the pedicle was noted and using a venous coupler device, the venous anastomosis was completed.
With the achievement of inflow and outflow, the anterior skin of the forearm was mobilized to cover the vascular pedicle. A 12/1000th of an inch skin graft was taken to cover the soft tissue defect over the fibula, and the surgery was concluded. There were no complications.
About Penn Orthoplastic Surgery
The Penn Orthoplastic Limb Salvage Center provides unique microsurgical and complex fracture expertise for patients at high-risk for limb amputation and those requiring reconstructive surgery for severe injury to the limbs. Led by a team of orthopaedic surgeons, plastic surgeons, vascular surgeons, reconstructive microsurgeons and other specialists, the Center provides integrated treatment for patients with significant extremity injuries that require complex care. The Center treats national and international patients and works closely with referring providers for a seamless transfer of care and follow up.