Alloplastic and Implant Materials for Bone Grafting: a Literature Review

Bone reconstruction aft er trauma, infection, tumour or congenital genetic disorder is an important subject of modern medicine usually relying on bone graft ing materials. Autologous bone or autograft is still considered the “gold standard” most eff ective in bone defect reconstruction and osseous regeneration. Having the advantages of autograft ing, a series of issues remain related to a limited donor material, painful graft taking and the risk of putative complications (nonunions, graft rejection, infection, iatrogenic fractures, post-microsurgery arteriovenous shunt thrombosis, etc.). Th erefore, improved biomaterials are demanded to adequately meet the autograft criteria. Choosing optimal graft materials becomes relevant, aside to the rationale of selecting new surgical techniques. Th e osteoconductive and osteoinductive property evaluation in modern osteoplastic materials comprises a research avenue into optimal graft development for osseous correction in maxillofacial surgery, neurosurgery, traumatology and orthopaedics. Such biomaterials can be combined with alloplastic graft s to attain the required properties of osteoconduction, osteoinduction and osteogenesis. Th is analytic literature review focuses on current state-of-the-art in alloplastic graft ing that, in our opinion, grounds the progress of auto- and allograft innovative development.

Thrombosis associated with ventriculoatrial shunts

Ventriculoatrial shunts are the most common second-line procedure for cases in which ventriculoperitoneal shunts are unsuitable. Shunting-associated thrombosis is a potentially life-threatening complication after ventriculoatrial shunt insertion. The overall prevalence of this complication is still controversial because of substantial differences in the numbers found in studies using clinical data and in those analyzing postmortem findings. The etiology of thrombosis may be multifactorial, including shunt catheter itself, contents of cerebrospinal fluid, shunt infection, and genetic disorder. The clinical presentation can vary widely, ranging from asymptomatic to a life-threatening condition. Timely recognition of thromboembolic lesions is critical for treatment. However, early diagnosis and management is still challenging because of a relatively long asymptomatic latency and lack of clear guideline recommendations. The purpose of this review is to provide an overview of ventriculoatrial shunt thrombosis, especially to focus on its etiopathogenesis, diagnosis, treatment, and prevention.

Auto-venous femoral-popliteal bypass in patients with critical lower extremity ischemia and coronary heart disease associated with diabetes melitus

Аim — to improve the results of treatment of patients with atherosclerotic lesions of the arteries of femoral-popliteal segment, who underwent auto­venous femoral-popliteal bypassgrafting.Materials and methods. During the period of years 2018 to 2021, 34 patients with critical ischemia of the lower extremities underwent autovenous shunting with a reversed great saphenous vein with treatment of the inner surface of the vein with a solution of cytostatics (paclitaxel). Besides, the treatment was analysed in two control groups, who underwent autovenous reverse vein shunting (30 patients) and autovenous in-situ shunting (33 patients). The follow-up periods lasted for 24 months. The evaluation criteria included the cases of shunt thrombosis, shunt stenosis, mortality, serious ischemic events — acute lower extremity ischemia, myocardial infarction, ischemic stroke, cases of high amputations of the lower extremities.Results. In the postoperative period, no deaths were observed; absence of complicationswas registered in 96 (98 %) patients. In the main group, the frequency of shunt thrombosis was 5 (14.7 %), hemodynamically significant restenosis was diagnosed in 6 patients (17.6 %), acute myocardial infarction in 1 patient (2.9 %). In the comparison group, 11 cases of autovenous shunt thrombosis were defined.Conclusions. Our clinical experience showed promising short- and medium-term results. The chosen surgical approach and topical application of cytostatic drugs enabled to achieve long-term patency of venous shunt, which is of particular importance for patients with diabetes mellitus.

Portosystemic shunting procedures for complicated portal hypertension: modern opportunities of mini-invasive technique

Aim. To improve the results of treatment for patients with complicated portal hypertension of cirrhotic genesis using the transjugular intahepatic portosystemic shunt with endovascular obliteration of the inflow pathways to the esophageal-gastric varicose veins.Material and methods. Transjugular intahepatic portosystemic shunt was performed in 172 patients with gastroesophageal variceal bleeding. The patients were divided into 3 clinical groups. The shunting procedure was applied to 62 patients. Another 110 patients underwent transjugular intahepatic portosystemic shunt and selective obliteration of the esophageal-gastric vein inflow pathways. The short-term and long-term results (up to 140 months), the incidence of thrombosis, recurrent bleeding and mortality, as well as their relationship with the established risk factors for complications were traced.Results. All patients achieved an effective reduction in the portosystemic pressure gradient and a reduction in the manifestations of portal hypertension. Recurrence of bleeding caused by shunt thrombosis occurred in 23 (13.3%) patients. In clinical group I (n = 62), this complication was noted in 9 (14.5%) patients, in II (n = 54) – 11 (20.4%) cases, in III (n = 56) – only in 3 (5.4%) cases. Bleeding-free survival decreased from 1.0 to 0.82 in 83.9 months, then plateaued. A sharp decrease in the Kaplan–Meier curve from 1.0 to 0.88 was observed within 24.5 months after the intervention. The largest number of deaths was in group I (30.6%), the smallest in group III (7.1%).Conclusion. Transjugular intahepatic portosystemic shunt supplemented by obliteration the inflows of the esophagealgastric varicose veins provides complete eradication of varicose veins, helps to reduce the frequency of recurrent bleeding and death.

Laparoscopic Distal Splenorenal Anastomosis

Introduction: Esophagogastric bleeding is the most formidable complication of the portal hypertension syndrome. At acute bleeding from varicose veins of the esophagus and stomach, mortality reaches 40 to 50% and is accompanied with the high risk of early hemorrhage recurrence in 30-50 % of survivors. Portosystemic shunt surgery provides for radical decompression of the portal vein system and reliably prevent hemorrhage recurrence. Purpose: To assess the possibility and efficacy of the Distal Splenorenal Anastomosis (DSRA) with a minimally invasive laparoscopic approach. Methods: The study included 28 patients with portal hypertension syndrome who underwent laparoscopic DSRA. By the Child-Pugh scale, class A was 42.9%, class B - 57.1%. The indication for surgical decompression of the portal system was the ineffectiveness of repeated sessions of endoscopic ligation with recurrence of varicose veins of the esophagus (21.5%) and/or bleeding from them (46.4%) or the presence of varicose veins of the stomach (32.1%). Results: Mean surgery time was 294±86 minutes. The maximum blood loss was 211±55 ml. The access conversion was performed in 10.7% of cases. In the postoperative period, the patients were in ICU for 1-2 days. The hospital stay and in-patients treatment duration was 9.4±2.5 days. Both in the early and in the long-term follow-up, there were no cases of gastroesophageal bleeding and shunt thrombosis. The portosystemic encephalopathy developed in 12% of cases. The surgical decompression of the portal system was featured by a decrease in the degree of esophagus varication in the long-term period. The maximum follow-up period was 46 months. Conclusion: Minimally invasive laparoscopic DSRA in patients with portal hypertension syndrome is a possible, safe and effective alternative treatment option.

Effectiveness of antithrombotic prophylaxis in paediatric cardiosurgical patients

<p><strong>Aim.</strong> To evaluate the effectiveness of prevention measures for thrombotic catheter-associated events in the perioperative management of patients undergoing cardiac surgery.</p><p><strong>Methods.</strong> A total of 433 paediatric and neonatal patients were included in the study during the period from January to December 2018. All patients received antithrombotic prophylaxis via systemic heparin administration.</p><p><strong>Results.</strong> Thirty-six patients displayed signs of thrombosis during the postoperative period (8.31%): 28 patients had venous thrombosis, while 6 had the Blalock-Taussig shunt thrombosis, and 2 had arterial thrombosis. The mortality rate was higher in the group with registered thrombosis than in the group without thrombosis (p = 0.01).</p><p><strong>Conclusion.</strong> The dosage regimen for children and neonatal patients should be according to age-associated antithrombotic drug standards. It requires an integral approach for evaluating the effectiveness of preventive and therapeutic measures.</p><p>Received 25 August 2020. Revised 18 December 2020. Accepted 22 December 2020.</p><p><strong>Funding:</strong> The study did not have sponsorship.</p><p><strong>Conflict of interest:</strong> Author declares no conflict of interest.</p>

Predictors of death after receiving a modified Blalock-Taussig shunt in cyanotic heart children: A competing risk analysis

Objective To determine risk factors affecting time-to-death ≤90 and >90 days in children who underwent a modified Blalock-Taussig shunt (MBTS). Methods Data from a retrospective cohort study were obtained from children aged 0–3 years who experienced MBTS between 2005 and 2016. Time-to-death (prior to Glenn/repair), time-to-alive up until December 2017 without repair, and time-to-progression to Glenn/repair following MBTS were presented using competing risks survival analysis. Demographic, surgical and anesthesia-related factors were recorded. Time-to-death ≤90 days and >90 days was analyzed using multivariate time-dependent Cox regression models to identify independent predictors and presented by adjusted hazard ratios (HR) and 95% confidence intervals (CI). Results Of 380 children, 119 died, 122 survived and 139 progressed to Glenn/repair. Time-to-death probability (95% CI) within 90 days was 0.18 (0.14–0.22). Predictors of time-to-death ≤90 days (n = 63) were low weight (<3 kg) (HR 7.6, 95% CI:2.8–20.4), preoperative ventilator support (HR 2.7, 95% CI:1.3–5.6), postoperative shunt thrombosis (HR 5.0, 95% CI:2.4–10.4), bleeding (HR 4.5, 95% CI:2.1–9.4) and renal failure (HR 4.1, 95% CI:1.5–10.9). Predictors of time-to-death >90 days (n = 56) were children diagnosed with pulmonary atresia with ventricular septal defect and single ventricle (compared to tetralogy of fallot) (HR 3.2, 95% CI:1.2–7.7 and HR 3.1, 95% CI:1.3–7.6, respectively), shunt size/weight ratio >1.1 vs <0.65 (HR 6.8, 95% CI:1.4–32.6) and longer duration of mechanical ventilator (HR 1.002, 95% CI:1.001–1.004). Shunt size/weight ratio ≥1.0 (vs <1.0) and ≥0.65 (vs <0.65) were predictors for overall time-to-death in neonates and toddlers, respectively (HR 13.1, 95% CI:2.8–61.4 and HR 7.8, 95% CI:1.7–34.8, respectively). Conclusions Perioperative factors were associated with time-to-death ≤90 days, whereas particular cardiac defect, larger shunt size/weight ratio, and longer mechanical ventilation were associated with time-to-death >90 days after receiving MBTS. Larger shunt size/weight ratio should be reevaluated within 90 days to minimize the risk of shunt over flow.

Catheter-induced acute Blalock–Taussig shunt thrombosis and bailout

Modified Blalock–Taussig shunt thrombosis is a life-threatening event. We describe an extremely rare catheter-induced shunt thrombosis in an infant with complex CHD and its successful treatment utilising a single low dose of local recombinant tissue plasminogen activator in conjunction with balloon angioplasty.