Bilateral Transfemoral Lower Extremity Transplantation: Result at 1 Year

Authors


Abstract

Upper limb transplantation has become a treatment option for upper limb amputees with good midterm results. Lower extremity transplantation has never been considered for fear of poor results. The authors present a bilateral transfemoral transplantation of lower extremities performed to a 22-year patient at 12 months of follow-up. The donor was a full HLA-mismatched female multiorgan donor. CMV status was D-/R-. A primary CMV infection coincident with an acute rejection occurred at 3 months and responded to treatment. At 1 year, the Tinel's sign is at malleolar level, there is active knee extension and active plantar flexion of the foot. The patient is walking between parallel bars. Further substantial improvements are expected with longer rehabilitation and follow-up.

Abbreviations
AK

above the knee

AR

acute rejection

BK

below the knee

CNI

calcineurin inhibitor

DSA

donor-specific antibodies

G-CSF

granulocyte- colony stimulating factor

MMF

mycophenolate mofetil

MRC

Medical Research Council

POD

postoperative day

POM

postoperative month

PTLD

posttransplant lymphoproliferative disease

ROM

range of motion

Tac

tacrolimus

Val

valgancyclovir

VCA

vascularized composite allotransplantation

Vascularized composite allotransplantation (VCA) is becoming an accepted treatment option for bilateral upper extremity amputees, with good mid-term results [1-3]. The indications for upper extremity transplantation are expanding, with excellent results recently reported in a transhumeral case [4]. Bilateral transfemoral (above knee, AK) traumatic amputation causes a profound functional impairment. Prosthetic adaptation may be impossible in some cases, despite aggressive rehabilitation protocols, rendering these patients confined to a wheelchair [5]. Lower extremity transplantation has typically been contraindicated, assuming the theoretical risks would outweigh the benefits. Classically, even lower limb replantation after traumatic amputation has been discouraged [6], although good results have been reported in below-knee (BK) replantations recently [7].

Extrapolating the experience of the authors in upper extremity transplantation and in lower limb replantation, a transfemoral bilateral transplantation was performed in July 2011 and reported herein at 12 months of follow-up. To the best of the authors' knowledge, no similar cases have been reported in the literature.

The recipient

The recipient was a 22-year-old male that suffered a bilateral traumatic AK amputation in a car crash 2 years before (Figure 1). The femur stump was 32-cm long on the right side and 41-cm long on the left (Figure 2). Blood group was O negative, CMV IgG– and EBV IgG+. HLA typing was A1 A24 B15 B44 DRB1*1406 DRB1*15. After an extensive rehabilitation program at a large university hospital, the patient was unable to walk with prostheses and used a wheelchair. Pain and socket instability prevented conventional prosthetic fitting. The patient refused osseointegrated prostheses because of perceived bad results communicated by rehabilitation peer patients. Tinel's sign of the sciatic nerves was located 10 cm above the amputation level. IRB approval was obtained from the hospital and the Spanish organ procurement organization (ONT).

Figure 1.

The recipient patient was a bilateral AK amputee through mid-femoral level on the right side and distal third on the left.

Figure 2.

Preoperative X-ray showing the level of bone amputation.

The donor and the transplantation procedure

The donor was a 26-year-old female multiorgan donor with brain death. Blood group was O negative, CMV and EBV IgG–. HLA typing was A2, B44, BW4, DR15 [2], DR17 [3], DR51, DR52, DQ6 [1] and DQ2. Crossmatching was negative. Transplantation was performed on July 11, 2011. The quadriceps and hamstring muscles, external iliac vessels and sciatic nerves were dissected and tagged bilaterally at the stumps in the recipient.

The procurement of the legs was performed after cardiac and liver retrieval at the same hospital. The lower extremities were cold perfused in situ. Thirty liters of University of Wisconsin solution were used for simultaneous liver, kidney and lower limbs perfusion without cross clamping. This large amount of solution was used to completely flush the vascular bed of the lower half of the body. No pressure control was used. The femoral vessels were dissected up to the common iliac artery and vein. Femoral osteotomies were performed 22- and 12-cm proximal to the knee joint line in the right and left sides, respectively. This level was estimated based on the previous recipient's height. The sciatic nerves were cut proximally at the sciatic notch. Cosmetic prostheses were affixed to the donor. The right limb was retrieved first, and was immediately transferred to the recipient's OR in a sterile plastic bag without additional cooling means. The left limb was retrieved afterwards, simultaneous with right limb transplantation, and was kept cooled in crushed ice in the meanwhile.

The right leg was transplanted first. The sequence of repairs was the same in both sides. Bone fixation was performed first with 4.5-mm locking plates and screws. Hamstring muscles were then repaired. The sciatic nerve was repaired using epineural interrupted suture. The quadriceps was sutured under tension with heavy absorbable material. No intraoperative cooling was used for the right limb. The iliac artery of the VCA was then flushed with warm (37°C) Ringer's solution. The vascular tree of the leg was filled with warm Ringer's solution and clamped. End-to-side anastomoses were performed to the recipient's external iliac vessels. The vein clamp was released first and then the arterial clamps, allowing revascularization. No significant adverse events took place upon revascularization. The left leg was kept cooled in crushed ice, without temperature measurement, during the right side reattachment, and the same sequence of surgical maneuvers was followed on the left side (Figures 3 and 4). Reperfusion of the second limb was performed 2 h after the first limb and it was well tolerated by the patient. A total of 12 units of packed red cells, six units of fresh frozen plasma and three units of platelets were transfused during and after the surgery. Total ischemia time was 3.5 h on the right side and 5.5 h on the left side. No fasciotomies were performed. An external fixator was inserted in the tibia bilaterally for postoperative suspension. Figure 5 shows patient 4 weeks postoperatively, a single-pin T scab scar is visible in the pretibial region (Figure 5).

Figure 3.

The right limb was transplanted first.

Figure 4.

The left extremity was transplanted after right one had been revascularized.

Figure 5.

The patient after both limbs were transplanted.

Pharmacologic treatment

Immunosuppressive treatment consisted on induction with alemtuzumab 30 mg IV, and maintenance with mycophenolate mophetyl (MMF) 1 g/12 h, tacrolimus (Tac) for trough levels of 10–17 ng/mL during the first month and 7–12 ng/mL thereafter, and tapering methylprednisolone (1 g on reperfusion, 250 mg for 2 days, 100 mg on POD3, 60 mg from POD 4–14 and progressive reduction thereafter; Figure 6). No CMV prophylaxis was instituted, given the D–/R– matching [8]. CMV replication was monitored weekly. The risk of deep venous thrombosis because of denervation of the calf veins was addressed with prophylaxis using Clopidogrel.

Figure 6.

Graphic depiction of the immunosuppressive treatment during the first postoperative 15 months.

Medical Evolution

No significant complications developed in the early postoperative period. At POM 4, the patient developed hypertriglyceridemia and was treated with gemfibrocil. At POD 90, Tac was changed for rapamycin in order to reduce Tac exposure and long-term risk of malignancy. Coincident with this, the patient developed CMV primary infection (CMV syndrome) and skin acute rejection (AR; Figure 7). IV valgancyclovir (Val) was started and IV methyl prednisolone (500 mg/day) was given for 5 days. Histology revealed a Banff grade I acute rejection (Figure 8), with positive C4d staining. DSA (flow cytometry) were negative. The AR was resistant to steroids. Intravenous immunoglobulin (IVIg) was given for 7 days and rapamycin was changed for Tac with rapid clinical and histological resolution of the skin changes (Figure 9). Neutropenia occurred at POD 95 (leucocyte counts 4500 per mL at POD 90, 660 per mL at POD 104) and responded to treatment with G-CSF (leucocyte counts 2680 per mL at POD 105 and 5810 per mL at POD 106). CMV replication became negative after 37 days of treatment. Val was stopped on day 307 after verification of cellular CMV immunity (CD8 T cell response against CMV, QuantiFERON-CMV; Ref. 8).

Figure 7.

AR at POM 3.

Figure 8.

Histology of the skin showing a Banff grade I acute rejection.

Figure 9.

Complete resolution of the AR at POM 4.

A second AR occurred on POM 9, Banff grade I (Figure 10), related to dose reduction of Tac and MMF because of transient diarrhea (Tac level 6.5 ng/mL and MMF level 3.4 mg/mL). Treatment with dose adjustment reversed the AR (Tac 8.6 and MMF 7.2 mg/mL at 10 days). Two episodes of deep abscess, unrelated to the bone fixation, developed at POM 6 within the left quadriceps, probably because of ischemic areas of distal muscle around the heavy muscular sutures. Acinetobacter spp., and enterococcus spp. were isolated from the exudates, both sensible to aztreonam. Treatment with surgical debridement and intravenous aztreonam for 6 weeks was curative. Bone healing occurred in the right side, but was delayed in the left side (Figure 11). The patient is using local ultrasound (EXOGEN Express, Ultrasound Bone Healing System, Smith & Nephew, Barcelona, Spain) and surgical revision (autologous bone grafting with or without fixation revision) will be performed depending on radiographic response. Renal function, blood pressure and glucose levels have remained normal. CMV replication and DSA have remained negative. Chimerism tests were not performed in this patient.

Figure 10.

Histology of the skin showing a 2° Banff grade I acute rejection.

Figure 11.

X-ray at POM 5 showing bone healing: bone healing has taken place on the right leg, but that it is delayed on left leg.

Rehabilitation protocol

Passive ankle exercises were started from POD 1. Passive knee range of motion (ROM) was started on POD 15. Active quadriceps contraction was allowed on POD 21, with progressive strength exercises. Hip extension and abduction active exercises were also performed. Ambulation with partial weight bearing was started in swimming pool on POM 4. Ambulation between parallel bars was started on POM 9 with rigid walking boots. Progressive weight bearing was allowed with partially healed osteotomies to stimulate bone healing.

Active ankle plantar flexion started at POM 7 on the left side and POM 8 on the right. Strengthening exercises were performed accordingly. Pressure compression stockings were used during the first 4 months for edema control.

Functional results

At 1-year follow-up, the patient had full passive ROM in both knees (0°–150°), with active knee extension. There was an extension lag of 30° and 45° on the left and right knees, respectively. Quadriceps strength was better on the left side. There was active flexion of both knees. Foot (ankle) plantar flexion was M4 (MRC score) on the left side and M3+ on the right. Tinel's sign was advancing at plantar level. At the time of this writing (POM 14) there is early recovery of dorsal ankle flexion at the left side. The patient had fully incorporated the transplanted legs into his body image. Walking between parallel bars was improving, although there was mild hip flexion to compensate for the knee extension lag (video S1). The ankles were not stable enough yet and rigid ankle–foot orthoses were used for walking exercises.

Discussion

Fourteen years after the first hand transplantation, VCA is an established treatment option for severe upper extremity amputations [1-3]. Given the significant potential complications, transplantation of nonvital organs (e.g. VCA) is only considered in patients whose quality of life is expected to improve dramatically. In the upper limb, this is the case in bilateral amputees and very doubtfully in unilateral cases [3]. In lower limb amputees, the functional impairment depends on the level of amputation. BK amputations can usually be successfully rehabilitated with prostheses. The loss of the knee, especially in bilateral AK amputations, makes prosthetic use significantly more difficult [5, 10]. Osseointegrated AK prostheses have been described, although the complication rate is high [11]. If, despite an aggressive rehabilitation program, the patient cannot adapt prostheses, he or she will be confined to a wheelchair. Making these patients walk again independently would be a major improvement in their quality of life.

The risk-benefit ratio in lower limb transplantation seems delicate, especially in the absence of precedents in the literature. The patient is subjected to a substantial Intraoperative risk, a lengthy rehabilitation process and lifelong immunosuppression. Only if the patient can walk independently with the transplanted legs is the procedure warranted. Lower limb replantation has typically been contraindicated due to reported poor results [6, 12, 13]. Recently encouraging results of leg replantation have been published [7]. Basic ambulation requires a sensate sole, a well aligned skeleton and active knee extension and hip abduction. Extrapolating the experience in high-energy lower limb trauma, it seemed realistic to achieve at least this basic function with a transplant.

The major Intraoperative concerns in this case were ischemia time, the drastic increase in the vascular bed relative to the volemia, and possible hypothermia resulting from reperfusing large amounts of cold tissue. The procurement of the legs was performed under circulatory arrest to avoid bleeding and potential donor destabilization compromising vital organ harvesting. Dissection in a bloodless field was rapid, compensating for the added ischemia time (total ischemia time of right and left limbs 3.5 and 5.5 h, respectively). The VCA vascular prefilling with warm crystalloids before anastomoses were performed helped prevent drastic blood pressure fall, keeping the ratio volemia-vascular-tree capacity constant. The systemic effect upon clamp release was more like a hemodilution (compensated in advance with packed red cell transfusion), rather than a volume depletion. The sequential revascularization also contributed to reduce the overall hemodynamic impact. Rewarming of the VCA just before revascularization was performed to avoid recipient hypothermia without compromising the cooling of the organ.

Immunosuppression was not different from other VCAs: induction with anti CD52 alemtuzumab and triple therapy with Tac, MMF and prednisone. The large mass of transplanted tissue did not seem to increase the immunosuppressive requirements. The inclusion of large amounts of vascularized bone marrow did not result in graft versus host disease, in keeping with previous experience in VCA. The role of chimerism in tolerance induction is well recognized, although its significance in VCA remains unclear. Chimerism was not tested in this case. CMV matching is important in VCA, and avoidance of high-risk D+/R– combinations has been recommended [14]. In the case presented a D– was considered mandatory and this prolonged the waiting list time. No CMV prophylaxis was performed, according to the best evidence available [8]. The source of the primary delayed CMV infection that the patient developed at POM 3 remains unclear (interpersonal or blood transfusion), and its occurrence is exceptional in D–/R– pairs with preemptive therapy as the present case [15, 16]. The coincidence of CMV replication and AR has been well described in the literature. In the case presented, the change of Tac for rapamycin was electively performed early, to avoid CNI exposure and long-term malignancy risk. In retrospect it proved to be a mistake, although the exact role it played in the AR remains unclear. Initial treatment with Val without reducing the IS and a steroid pulse was decided. The skin changes did not resolve. Although DSA were negative and C4d staining is not specific, a second line treatment was indicated. In order to reduce the risk of PTLD associated to repeated doses of lymphodepleting antibodies, IVIg were given [17]. The clinical significance of positive C4d staining in the absence of DSA is uncertain in VCA [18]. The relative role of IVIg or the reintroduction of Tac in the resolution of the AR remains unclear in this case.

The functional results in this case, at 1-year follow-up, are still preliminary and expected to improve very substantially. Unlike transplanted solid organs, whose function is restored immediately after clamp release, VCAs require a long period of rehabilitation and nerve regeneration to have useful function. This period is 6–18 months in hand transplantations (the higher the level, the longer the reinervation time), and in a transfemoral transplantation this time could be over 2 years. Nerve regeneration is still under way. Tinel's sign has advanced approximately at a rate of 2.5 mm/day, more than twice the normal velocity. Tinel sign has just reached the sole of the feet. Monofilaments or 2PD studies will be performed after Tinel's sign is at the toes, since plantar sensation is thought to be the key sensitivity. Calcineurin inhibitors are known to enhance nerve regeneration, and this is a bonus in VCA [19]. Foot (ankle) plantar flexion is strong, although dorsal flexion is not yet present. This pattern of delayed peroneal nerve regeneration, related to the tibial nerve, is commonly seen after high sciatic nerve injuries [20]. Active ROM of the knees in this case depended on the strength of the remnants of muscle at the stumps, as the part of thigh muscles of donor's origin remained denervated. Reinervation of the donor quadriceps muscle through surgical coaptation of the femoral nerves would be necessary should the remnant of the quadriceps at the stumps be minimal (very short femoral stump). It is uncertain if the muscle strength recovered in these hypothetical cases would be enough for active knee extension. Interestingly, these are the cases with the lowest prosthetic fitting rate.

Although this is a single case report (Figure 12) with relatively short follow-up, lower limb transplantation can be performed safely in bilateral AK amputees and, in light of the results at 1 year, could probably allow these patients to walk independently. If this is confirmed in longer follow-up of this case, lower limb transplantation could become a treatment option in selected bilateral AK amputees. Besides the uncertain long-term fate of the VCA, it remains undetermined the future role of lower extremity transplantation in quadrimembral amputees, especially in children surviving meningococcal sepsis.

Figure 12.

Pre- and postoperative recipient (left) and pre and postoperative inferior limbs CT 3D reconstruction (right) showing bone situation at POM 12.

Disclosure

The authors of this manuscript have no conflicts of interest to disclose as described by the American Journal of Transplantation.

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