Portal vein reconstruction using primary anastomosis or venous interposition allograft in pancreatic surgery.

OBJECTIVE: Superior mesenteric vein/portal vein (SMV/PV) resection and reconstruction during pancreatic surgery are increasingly common. Several reconstruction techniques exist. The aim of this study was to evaluate characteristics of patients and clinical outcomes for SMV/PV reconstruction using interposed cold-stored cadaveric venous allograft (AG+) or primary end-to-end anastomosis (AG-) after segmental vein resections during pancreatic surgery. METHODS: All patients undergoing pancreatic surgery with SMV/PV resection and reconstruction from 2006 to 2015 were identified. Clinical and histopathologic outcomes as well as preoperative and postoperative radiologic findings were assessed. RESULTS: A total of 171 patients were identified. The study included 42 and 71 patients reconstructed with AG+ and AG-, respectively. Patients in the AG+ group had longer mean operative time (506 minutes [standard deviation, 83 minutes] for AG+ vs 420 minutes [standard deviation, 91 minutes] for AG-; P < .01) and more intraoperative bleeding (median, 1000 mL [interquartile range (IQR), 650-2200 mL] for AG+ vs 600 mL [IQR, 300-1000 mL] for AG-; P < .01). Neoadjuvant therapy was administered more frequently for patients in the AG+ group (23.8% vs 8.5%; P = .02). Patients with AG+ had a longer length of tumor-vein involvement (median, 2.4 cm [IQR, 1.6-3.0 cm] for AG+ vs 1.8 cm [IQR, 1.2-2.4 cm] for AG-; P = .01), and a higher number of patients had a tumor-vein interface >180 degrees (35.7% for AG+ vs 21.1% for AG-; P = .02). There was no difference in number of patients with major complications (42.9% for AG+ vs 36.6% for AG-; P = .51) or early failure at the reconstruction site (9.5% for AG+ vs 8.5% for AG-; P = 1). A subgroup analysis of 10 patients in the AG+ group revealed the presence of donor-specific antibodies in all patients. CONCLUSIONS: The short-term outcome of SMV/PV reconstruction with interposed cold-stored cadaveric venous allografts is comparable to that of reconstruction with primary end-to-end anastomosis. Graft rejection could be a contributing factor to severe stenosis in patients reconstructed with allograft.

Revision surgery after interbody fusion with rhBMP-2: a cautionary tale for spine surgeons.

Recombinant human bone morphogenetic protein-2 (rhBMP-2) promotes the induction of bone growth and is widely used in spine surgery to enhance arthrodesis. Recombinant human BMP-2 has been associated with a variety of complications including ectopic bone formation, adjacent-level fusion, local bone resorption, osteolysis, and radiculitis. Some of the complications associated with rhBMP-2 may be the result of rhBMP-2 induction of the inflammatory host response. In this paper the authors report on a patient with prior transforaminal lumbar interbody fusion (TLIF) using an interbody cage packed with rhBMP-2, in which rhBMP-2 possibly contributed to vascular injury during an attempted anterior lumbar interbody fusion. This 63-year-old man presented with a 1-year history of worsening refractory low-back pain and radiculopathy caused by a Grade 1 spondylolisthesis at L4-5. He underwent an uncomplicated L4-5 TLIF using an rhBMP-2-packed interbody cage. Postoperatively, he experienced marginal improvement of his symptoms. Within the next year and a half the patient returned with unremitting low-back pain and neurogenic claudication that failed to respond to conservative measures. Radiological imaging of the patient revealed screw loosening and pseudarthrosis. He underwent an anterior retroperitoneal approach with a plan for removal of the previous cage, complete discectomy, and placement of a femoral ring. During the retroperitoneal approach the iliac vein was adhered with scarring and fibrosis to the underlying previously operated L4-5 interbody space. During mobilization the left iliac vein was torn, resulting in significant blood loss and cardiac arrest requiring chest compression, defibrillator shocks, and blood transfusion. The patient was stabilized, the operation was terminated, and he was transferred to the intensive care unit. He recovered over the next several days and was discharged at his neurological baseline. The authors propose that the rhBMP-2-induced host inflammatory response partially contributed to vessel fibrosis and scarring, resulting in the life-threatening vascular injury during the reoperation. Spine surgeons should be aware of this potential inflammatory fibrosis in addition to other reported complications related to rhBMP-2.

Vein to artery allografts: experimental evidence of immunological sensitivity in rats.

Vein allografts were studied in rats using the major histocompatibility complex-incompatible DA (RTIa) and LEW (RTI1) inbred strains. Allografts from DA rats were inserted in to 22 LEW hosts, and vice versa, by interposing a 5 mm segment of donor iliolumbar vein into a defect in the host's iliac artery (1 mm in diameter), using microsurgical techniques. Grafts were left in situ for 6 weeks and were then tested for evidence of sensitization by the insertion of an allogeneic fetal heart from the donor strain into the host's foot pad. The fetal heart beat was recorded with an ECG and the time of rejection determined by the cessation of ECG activity. As controls, allogeneic donor fetal hearts were implanted into 40 host rates (20 of each strain) which had not previously received a donor vein allograft. These were monitored by ECG, as above. Control LEW host rats rejected DA fetal hearts in a mean time of 8.45 days. Control DA hosts rejected LEW fetal hearts in 8.70 days. DA hosts with LEW vein allografts did not reject donor fetal hearts significantly sooner (mean 8.33 days) than the controls. However, LEW host rats with allografted DA veins rejected subsequent DA fetal hearts in 7.18 days, which was significantly sooner than in controls (8.45 days). These data provide evidence of sensitization of the rejection response by vein allografts.

[Venous immunomorphology in acute experimental thrombosis and human recurrent migrating thrombophlebitis]. / Immunomorfologiia ven pri éksperimental'nom ostrom tromboze i pri retsidiviruiushchem migriruiushcem tromboflebite cheloveka.

The direct immunofluorescence procedure was used to demonstrate immune complexes (fixed immunoglobulins) in the internal and external sheath of veins of a dog with experimental acute thrombosis caused by partial ligation of the ileofemoral vein in the presence of immunization of the animal with extracts of auto- and homologous vein tissue. The results suggest the participation of auto-immune processes in the pathogenesis of acute thrombosis of the main veins.