Direct oral anticoagulants (DOACs) and neck of femur fractures: Standardising the perioperative management and time to surgery

Demographic projections for hip fragility fractures indicate a rising annual incidence by virtue of a multimorbid, ageing population with more noncommunicable diseases (NCDs). NCDs are characterised by slow progression and long duration ranging from ischaemic cardiovascular disease, cerebrovascular disease, diabetes, chronic obstructive pulmonary disease to various cancers. Management of this disease burden often involves commencing patients on oral anticoagulants to reduce the risk of thromboembolic events. The use of direct oral anticoagulants (DOACs) in clinical practice has increased due to their rapid onset of action, short half-life and predictable anticoagulant effects, without the need for routine monitoring. Safe and timely surgical intervention relies on reversal of anticoagulants. However, the lack of specific evidence-based guidelines for the perioperative management of patients on DOACs with hip fractures has proved challenging; in particular, the accessibility of DOAC-specific assays, justification of the cost-benefit ratio of targeted reversal agents and indications for neuraxial anaesthesia. This has led to potentially avoidable delays in surgical intervention. Following a literature review of the pharmacokinetic and pharmacodynamics of commonly used DOACs in our region including the role of surrogate markers, we propose a systematic, evidence-based guideline to the perioperative management of hip fractures DOACs. We believe this standardised protocol can be easily replicated between hospitals. We recommend that if patients are deemed suitable for a general anaesthesia, with satisfactory renal function, optimal surgical time should be 24 h following the last ingested dose of DOAC.     

Screw angulation affects bone-screw stresses and bone graft load sharing in anterior cervical corpectomy fusion with a rigid screw-plate construct: a finite element model study

Background contextAnterior corpectomy and reconstruction with bone graft and a rigid screw-plate construct is an established procedure for treatment of cervical neural compression. Despite its reliability in relieving symptoms, there is a high rate of construct failure, especially in multilevel cases.PurposeThere has been no study evaluating the biomechanical effects of screw angulation on construct stability; this study investigates the C4–C7 construct stability and load-sharing properties among varying screw angulations in a rigid plate-screw construct.Study designA finite element model of a two-level cervical corpectomy with static anterior cervical plate.MethodsA three-dimensional finite element (FE) model of an intact C3–T1 segment was developed and validated. From this intact model, a fusion model (two-level [C5, C6] anterior corpectomy) was developed and validated. After corpectomy, allograft interbody fusion with a rigid anterior screw-plate construct was created from C4 to C7. Five additional FE models were developed from the fusion model corresponding to five different combinations of screw angulations within the vertebral bodies (C4, C7): (0°, 0°), (5°, 5°), (10°, 10°), (15°, 15°), and (15°, 0°). The fifth fusion model was termed as a hybrid fusion model.ResultsThe stability of a two-level corpectomy reconstruction is not dependent on the position of the screws. Despite the locked screw-plate interface, some degree of load sharing is transmitted to the graft. The load seen by the graft and the shear stress at the bone-screw junction is dependent on the angle of the screws with respect to the end plate. Higher stresses are seen at more divergent angles, particularly at the lower level of the construct.ConclusionThis study suggests that screw divergence from the end plates not only increases load transmission to the graft but also predisposes the screws to higher shear forces after corpectomy reconstruction. In particular, the inferior screw demonstrated larger stress than the upper-level screws. In the proposed hybrid fusion model, lower stresses on the bone graft, end plates, and bone-screw interface were recorded, inferring lower construct failure (end-plate fractures and screw pullout) potential at the inferior construct end.     

Distinct effects of surgical denervation on hepatic perfusion, bowel ischemia, and oxidative stress in brain dead and living donor porcine models.

The liver function and perfusion following brain death is mainly influenced by the sympathetic nerves and hormones. We examined the specific influence of surgical liver denervation on systemic and hepatic perfusion parameters, bowel ischemia and oxidative stress in hemodynamically stable BD and control (living donor [LD]) pigs. Brain death was induced in 8 pigs via saline infusion into the balloon of an epidural Tieman-catheter (1 mL/15 minutes) and compared to the control group (n = 6) over 4 hours. At 2 hours postoperatively, complete liver denervation was initiated. We analyzed systemic cardiocirculatory parameters (mean arterial pressure, aortic flow, bowel ischemia (endotoxin, and endotoxin-neutralizing capacity) and oxidative stress (total glutathione in erythrocytes [tGSH(E)]) and compared them to local/hepatic perfusion parameters (hepatic artery and portal venous flow, liver blood flow index, and microperfusion), local bowel ischemia (intramucosal pH [pHi] of stomach [pHi(S)]/colon[pHi(C)]), and liver oxidative stress (glutathione [rGSH(L), GSSG(L)]). Following brain death, the parameters including mean arterial pressure, aortic flow, pHi, endotoxin, and tGSH(E) showed no significant changes at 2 hours. Portal venous flow and microperfusion were decreased significantly and hepatic arterial buffer response was ineffective. Hepatic oxidative stress was increased in BD animals (decrease rGSH(L), increase GSSG(L)). Surgical denervation/manipulation increased portal venous flow significantly, hepatic arterial buffer response became effective, and stomach pHi decreased (BD and LD groups). Hepatic oxidative stress was reduced in the BD group (increase rGSH(L)/GSSG(L); P < 0.001) while it was increased in the LD group (decrease rGSH(L)/GSSG(L); P < 0.001). In conclusion, denervation reduces hepatic oxidative stress in BD only in contrast to the LD. The reciprocal effect of denervation depends on the state of neural activation and postulates a potential benefit of surgical denervation before organ harvesting in brain death.     

Swelling behavior of a genetically engineered silk-elastinlike protein polymer hydrogel

The influence of environmental conditions such as pH, temperature, and ionic strength on the equilibrium swelling ratio of physically crosslinked networks of a genetically engineered silk-elastinlike protein-based copolymer (SELP) with an amino acid repeat sequence of [(GVGVP)4GKGVP(GVGVP)3(GAGAGS)4]12 was investigated. The effects of gelation cure time and initial polymer concentration on the equilibrium swelling ratio and soluble fraction of the hydrogels were also studied. It was found that the soluble fraction linearly correlated with the initial polymer concentration at higher gelation times. Soluble fraction results suggest that final hydrogel water content may be controlled by both initial polymer concentration and gelation time. Equilibrium swelling studies demonstrated that these hydrogels are relatively insensitive to environmental changes such as pH, temperature, and ionic strength. Over the concentration range studied, it was found that an increase in gelation time at 37 degrees C resulted in lower hydrogel weight equilibrium swelling ratios, which corresponds to less soluble polymer released post-gelation. Together, these results have implications for the controlled delivery of bioactive agents from silk-elastinlike hydrogels.     

Endogenous animal models of intracranial aneurysm development: a review

Neurosurgical Review - The pathogenesis and natural history of intracranial aneurysm (IA) remains poorly understood. To this end, animal models with induced cerebral vessel lesions mimicking human...     

Aneurysm formation of pericardial patch in Manouguian procedure

Pericardial patch has been used to repair cardiac defects; however, its strength as an aortoplasty patch to tolerate systemic pressure is a matter of debate. We report an aneurysmal dilatation of pericardial patch in aortoplasty. Our patient was a 56-year-old female known case of rheumatic heart disease that underwent redoes mitral and aortic valve replacements along with Manouguian aortoplasty at the age of 44?years old. After 2?months, she was readmitted with a diagnosis of endocarditis. Echocardiography revealed a small cavity in the posterior wall of the aorta. She responded to medical therapy and discharged in a good condition. Twelve years later, she was scheduled to undergo reoperation due to a severe paraprosthetic aortic valve leakage and a pericardial patch aneurysm. The leaking prosthetic aortic valve was explanted and the aneurysmal tissue was replaced with a polyethylene terephthalate patch.     

Endovenous laser ablation of the great saphenous vein versus high ligation: long-term results

Endovenous laser therapy (EVLT) for greater saphenous vein (GSV) insufficiency is a relatively new method of treatment only recently made available in Iran. This is the first long-term randomized trial comparing EVLT with high ligation of saphenous vein (HLS) in the Iranian population. Sixty-five patients met the inclusion criteria and were divided into homogenous treatment groups of EVLT (n?=?30) or HLS (n?=?35). Clinical severity, etiology, anatomy, pathophysiology (CEAP) classification and Aberdeen Varicose Vein Symptom Severity Scores (AVSS) were used to determine disease severity and symptoms before and after the procedure in both groups. Outcome was measured by the rate of recurrence as shown in Doppler ultrasonography evaluation. Follow-up was conducted 1 week and 3, 6, 12, and 18 months after the intervention. The occlusion rate of GSV was similar in both groups (93.6 % for EVLT, 88.3 for HLS) at 18 months of follow-up. The median CEAP score showed a dramatic decrease in both groups after 1 week which was sustained for the rest of the study. The Aberdeen Varicose Vein Symptom Severity score was significantly lower in the EVLT group at 12 and 18 months of follow-up. There was no significant difference in patient satisfaction in both groups. Our findings show that EVLT may offer a better long-term relief of symptoms. This, alongside its better cosmetic outcome, and less invasive anesthesia requirements may make it the favorable choice for treatment of GSV insufficiency.