Retrospective analysis of medium-term outcomes following anterior lumbar interbody fusion surgery performed in a tertiary spinal surgical centre.

INTRODUCTION: Anterior lumbar interbody fusion (ALIF) can treat spondylolisthesis, degenerative disc disease and pseudoarthrosis. This approach facilitates complete discectomy, disc space distraction, indirect decompression of neural foramina and placement of large interbody devices. Several intra- and postoperative complications can be attributed to the anterior approach: vascular/visceral injury, hypogastric plexus injury and urogenital consequences. Spine-specific complications include implant migration, graft failure, pseudoarthrosis and persistent symptomology. METHODS: This retrospective study reviewed patient demographics, medium-term outcomes and complication rates following ALIF surgery performed over a 5-year period. A total of 110 consecutive patients had undergone ALIF surgery at a single tertiary spinal centre. The database was reviewed with a primary outcome of identifying postoperative 90-day complications and whether a revision anterior operation was required after primary ALIF. RESULTS: No patients required revision anterior operation after their primary ALIF surgery by final follow-up. Out of 110 patients, 11 (10%) recorded a complication attributed to the anterior stage of their operation within 90 days. CONCLUSIONS: Our 90-day complication rate of 10% lies within the 2.6% acute complication and 40% overall complications rates described in previous literature. The risk of vascular/visceral injury is significant (3%) and we recommend that ALIF be performed as a dual surgeon procedure with a vascular-trained access surgeon accompanying the spinal surgeon. ALIF is a valid revision surgical option for failed posterior approaches leading to complications such as pseudoarthrosis. In our sample, 89% of patients were managed with posterior fixation to augment the anterior fusion as, biomechanically, this is a proven construct.

Surveillance optimisation to detect poliovirus in the pre-eradication era: a modelling study of England and Wales.

Surveillance for acute flaccid paralysis (AFP) cases are essential for polio eradication. However, as most poliovirus infections are asymptomatic and some regions of the world are inaccessible, additional surveillance tools require development. Within England and Wales, we demonstrate how inclusion of environmental sampling (ENV) improves the sensitivity of detecting both wild and vaccine-derived polioviruses (VDPVs) when compared to current surveillance. Statistical modelling was used to estimate the spatial risk of wild and VDPV importation and circulation in England and Wales. We estimate the sensitivity of each surveillance mode to detect poliovirus and the probability of being free from poliovirus, defined as being below a pre-specified prevalence of infection. Poliovirus risk was higher within local authorities in Manchester, Birmingham, Bradford and London. The sensitivity of detecting wild poliovirus within a given month using AFP and enterovirus surveillance was estimated to be 0.096 (95% CI 0.055-0.134). Inclusion of ENV in the three highest risk local authorities and a site in London increased surveillance sensitivity to 0.192 (95% CI 0.191-0.193). The sensitivity of ENV strategies can be compared using the framework by varying sites and the frequency of sampling. The probability of being free from poliovirus slowly increased from the date of the last case in 1993. ENV within areas thought to have the highest risk improves detection of poliovirus, and has the potential to improve confidence in the polio-free status of England and Wales and detect VDPVs.

Early Experience of Endovascular Repair of Post-dissection Aneurysms Involving the Thoraco-abdominal Aorta and the Arch.

OBJECTIVES: Outcomes are reported in management of post-dissection aneurysms involving the aortic arch and/or thoraco-abdominal segment (TAAA) treated with fenestrated and branched (complex) endografts. METHODS: This report includes all patients with chronic post-dissection aneurysms >55 mm in diameter, deemed unfit for open surgery, treated using complex endografts between October 2011 and March 2015. When appropriate, staged management strategies including left subclavian artery revascularization, thoracic endografting, dissection flap fenestration or tear enlargement, and other endovascular procedures were performed at least 3 weeks prior to definitive complex endovascular repair. The following outcome data were collected prospectively at discharge, 12 months and annually thereafter: technical success, endoleaks, target vessel patency, false lumen patency, aneurysm diameter, major and minor complications, re-interventions, and mortality. RESULTS: The cohort comprised 23 patients with a median age of 65 years. Staged procedures were performed in 14 patients (61%). Seven patients with dissections involving the arch were treated with inner branched endografts, and 16 TAAA patients were treated with fenestrated or branched endografts. The technical success rate was 71% following arch repair and 100% following TAAA repair. During early follow up, one of the arch group patients died and one in the TAAA group suffered spinal cord ischemia. The median follow up was 12 months (range 3-48), during which time one patient died of causes unrelated to aneurysm or treatment. Two early re-interventions were performed in the arch group to correct access vessel complications and there were a further two late re-interventions in the TAAA group to treat endoleaks. All target vessels (n = 72) remained patent. CONCLUSIONS: This experience indicates that complex endovascular repair of post-dissection aneurysms is a viable alternative to open repair in patients deemed unfit for open surgery. There are insufficient data to allow comparison with the outcome of open surgery in anatomically similar, but fit, patients.

Current and future perspectives in the repair of aneurysms involving the aortic arch.

The repair of aneurysms involving the aortic arch is technically and physiologically demanding. Historically, these aneurysms have been treated using open surgical techniques that require cardiopulmonary bypass and deep hypothermic circulatory arrest. Many patients have been deemed "untreatable" and among those selected for surgery there are reported risks of death in 2% to 16.5% and stroke rates ranging from 2% to 18%. "Hybrid arch repair" combines one of a number of open surgical procedures (to secure a proximal landing zone for an endograft) with subsequent or immediate placement of an endograft in the arch and descending aorta. Although this concept is described as "minimally invasive" because it avoids aortic cross-clamping and hypothermic circulatory arrest, the morbidity and mortality rates remain considerable (mortality 0% to 15%, stroke 0% to 11%). Ongoing development of endograft technology has enabled total endovascular repair of complex aortic aneurysms involving the visceral segment, using fenestrated and branched endografts. Encouraging early results in this anatomy have inspired extension of the concept to include the aortic arch and great vessels. These strategies can be considered in patients generally at high-risk for the conventional procedures. However, the endeavour is at an early stage of its development and the arch poses unique challenges including the potential for stroke, angulation of the arch and the great vessel ostia to the arch, extremely high volume flow, three-dimensional pulsation and rotation with the cardiac cycle and the proximity of the aortic valve and coronary arteries.

The impact of early pelvic and lower limb reperfusion and attentive peri-operative management on the incidence of spinal cord ischemia during thoracoabdominal aortic aneurysm endovascular repair.

OBJECTIVE/BACKGROUND: Spinal cord ischemia (SCI) is a devastating complication following endovascular thoracoabdominal aortic aneurysm (TAAA) repair. In an attempt to reduce its incidence two peri-procedural changes were implemented by the authors in January 2010: (i) all large sheaths are withdrawn from the iliac arteries immediately after deploying the central device and before cannulation and branch extension to the visceral vessels; (ii) the peri-operative protocol has been modified in an attempt to optimize oxygen delivery to the sensitive cells of the cord (aggressive blood and platelet transfusion, median arterial pressure monitoring >85 mmHg, and systematic cerebrospinal fluid drainage). METHODS: Between October 2004 and December 2013, 204 endovascular TAAA repairs were performed using custom made devices manufactured with branches and fenestrations to maintain visceral vessel perfusion. Data from all of these procedures were prospectively collected in an electronic database. Early post-operative results in patients treated before (group 1, n = 43) and after (group 2, n = 161 patients) implementation of the modified implantation and peri-operative protocols were compared. RESULTS: Patients in groups 1 and 2 had similar comorbidities (median age at repair 70.9 years [range 65.2-77.0 years]), aneurysm characteristics (median diameter 58.5 mm [range 53-65 mm]), and length of procedure (median 190 minutes [range 150-240 minutes]). The 30 day mortality rate was 11.6% in group 1 versus 5.6% in group 2 (p = .09). The SCI rate was 14.0% versus 1.2% (p < .01). If type IV TAAAs were excluded from this analysis, the SCI rate was 25.0% (6/24 patients) in group 1 versus 2.1% (2/95 patients) in group 2 (p < .01). CONCLUSION: The early restoration of arterial flow to the pelvis and lower limbs, and aggressive peri-operative management significantly reduces SCI following type I-III TAAA endovascular repair. With the use of these modified protocols, extensive TAAA endovascular repairs are associated with low rates of SCI.

Chronic dissection - indications for treatment with branched and fenestrated stent-grafts.

The treatment of chronic aortic dissection is a major challenge for the vascular surgeon. Close imaging follow-up after the acute episode frequently identifies dilation of untreated aortic segments. Aortic dissection often extends to both the supra-aortic trunks and to the visceral aorta. The poor medical condition that often characterizes these patients may preclude extensive open surgical repair. Recent advances in endovascular techniques provide a valid alternative to open surgery. These complex lesions can now be managed using thoracic branched and fenestrated endografts. However, clinical data are scarce and only 3 small series from 3 high-volume aortic centers are currently available. Careful anatomical study on 3D workstations is mandatory to select patients that are candidates for complex endovascular exclusion; a specific focus on the available working space within the true lumen, extension to the arch and/or the visceral/renal arteries, and false lumen perfusion of visceral vessels is required. An excellent understanding of those anatomic details demands high-quality preoperative CTA. Intraoperative advanced imaging applications are a major adjunct in the achievement of technical success.

A new score to predict post operative complications after endovascular treatment of thoraco abdominal aortic aneurysms.

BACKGROUND: The endovascular treatment of thoraco abdominal aortic aneurysms (TAAA) is a minimally invasive solution. However, patient selection remains a major problem. We have analysed our experience to identify the risk factors for post-operative morbidity and mortality and to construct a scoring system to identify those patients likely to benefit from this treatment. METHODS: We have analysed a consecutive cohort of patients treated electively for TAAA using endovascular techniques between 2006 and October 2012. All data were collected prospectively. The risk factors associated with spinal cord ischemia (SCI), the need for post-operative dialysis and 30 day mortality were determined using multivariate statistical techniques and a logistic regression model including all variables that were significant on univariate analysis (p < 0.05). A predictive score was calculated using a Received Operating Characteristic (ROC) curve, defining best specificity and sensibility. RESULTS: We analysed the data from 123 patients (median age 70 years). The 30 day mortality rate was 8% (10 patients). The SCI rate was 6% (7 patients). One patient (1%) required long-term dialysis after the aortic procedure. The cumulative early mortality, SCI and permanent dialysis rate was 14% (17 patients). In multivariate analysis, adverse outcome was associated with advanced age (OR = 1.110 ; p = 0.022), and Crawford type I or II or III (OR = 9.292 ; p = 0.002) as compared with Crawford type IV. Pre-operative beta blocker (BB) treatment was a protective factor (OR = 0.099 ; p = 0.005). A predictive score was then constructed : Score = -10.060 + 0.104x(A) +2.229x(B) -2.315x(C) (A = patient age ; B = 1 if TAAA Crawford type 1, 2 or 3, 0 if TAAA type 4 ; C = 1 if on-going BB treatment (30 days pre-surgery minimum), 0 if none). Its sensitivity and specificity were 88% and 89% respectively. CONCLUSIONS: We propose a simple predictive scoring system. This tool is useful in predicting the most feared complications after endovascular TAAA repair and has potential use in the identification and counselling of vulnerable patients being considered for surgery. More data are needed to refine the prediction of individual operative risks.

Chronic type B dissections: are fenestrated and branched endografts an option?

While there are centers reporting encouraging outcomes after endovascular repair of thoracoabdominal aortic aneurysms, chronic dissections (a specific etiological subgroup of thoracoabdominal aneurysms) present an even greater technical and clinical challenge. There are particular technical issues associated with the management of the proximal sealing zone, the need to work in a narrow aortic lumen and also to maintain perfusion of all target (visceral and supra-aortic) vessels including those perfused by the false lumen. We present here the various endovascular options available for the treatment of these complex aortic lesions.

Functional feeding responses of piscivorous fishes from the northeast US continental shelf.

The functional feeding response forms of piscivorous fishes used in multispecies and ecosystem modeling have been questioned because they were mostly conjectural or solely based on laboratory studies. Here, we investigate the functional feeding response of seven species of piscivorous fishes on four species of their prey from the northeast US continental shelf using field data that spans 30 years. Our study confirmed that Holling's types II and III functional responses are the most common functional responses for piscivorous fishes in this region. However, our analyses also revealed that differences exist between piscivorous fishes' functional responses, and, therefore, combining functional responses of piscivores is probably not appropriate in multispecies and ecosystem modeling. In the absence of specific predator-prey functional responses, we suggest that, for cruising, actively attacking predators, a type II functional response is slightly preferable; for a sedentary, ambush predator, a type III functional response is slightly preferable; at low prey densities for a generic fish predator, a type III functional response should be used; and at moderate to high prey densities, either should work sufficiently. Because we have shown that the functional response of a particular predator to individual prey species varies, these relationships must be further evaluated as we continue to develop and employ multispecies and ecosystem modeling.

Endovascular thoracoabdominal aortic aneurysm repair: a literature review of early and mid-term results.

Successful endovascular repair of abdominal aortic aneurysms (AAA) requires undilated proximal (infrarenal neck) and distal landing zones (common or external iliac arteries). A range of approved endografts are available to exclude such aneurysms. Recent multicentric prospective randomized trials have demonstrated a short and midterm decrease in aneurysm-related deaths of the endovascular technique compared to open surgery. These results have induced an overall increase in the rate of endovascular repair of AAA. Patients with more complex aortic aneurysms, involving the visceral vessels (juxta, para and thoraco-abdominal aneurysms (TAAA), have increased perioperative morbidity and mortality after open repair compared to AAA. These patients could potentially benefit from an endovascular approach. Branched and fenestrated endografts have been developed to address this endovascular challenge. This review was carried out on the current literature evaluating these new endovascular complex procedures. Spinal cord ischemia, 30-day mortality and branch patency rates after endovascular exclusion of TAAA ranged from 2.7% to 20%, 0% to 9.1% and 96% to 100% respectively. Mid-term results of endovascular complex aortic repairs are favourable compared to open surgery in high risk patients. Long-term results will be necessary to evaluate specific complications such as migration, material fatigue and component separation that can result in loss of visceral branches.

Autogenous brachial-brachial fistula for vein access. Haemodynamic factors predicting outcome and 1 year clinical data.

UNLABELLED: Two-stage autogenous brachial vein-brachial artery access (ABBA) has been proposed as an option where adequate superficial vein is not available for the creation of conventional haemodialysis fistulae. METHODS: This report depicts the clinical outcome of a series of 17 consecutive patients who underwent ABBA in a single centre. Of the 17 patients, nine had had at least one previous arterioventricular (AV) fistula or graft, and eight were new to haemodialysis. Patencies were assessed using the Kaplan-Meier survival analysis. RESULTS: In 14 patients, the brachial vein was transposed (82%) and the time to transposition ranged from 4 to 26 weeks (median time: 6 weeks). The functional patency rate was 45.75% at 12 months. After stage one, all fistulas that went on to develop well had a brachial vein flow of at least 900 ml min(-1), and this was significantly higher than in fistulas that failed to develop (p=0.005). The maturation rate in our study was 65% and the median time to cannulation of the fistula was 8 weeks from the stage 1. Of the 17 patients, 12 (71%) experienced at least one complication. Ten (59%) demonstrated moderate-to-severe stenoses; eight of which necessitated angioplasty and/or percutaneous mechanical thrombolysis. CONCLUSIONS: ABBA was characterised by a high incidence of complications and a long period to achieve maturation. Despite close monitoring and a high rate of secondary interventions, the patency rate was low. With this experience, we now only consider it an alternative in patients without adequate superficial veins, who have had failed grafts or where there is a very high risk of infection.

Zenith abdominal aortic aneurysm endovascular graft: a literature review.

The early experience of endovascular aneurysm repair (EVAR) using ''first generation'' devices was disappointing. There was an appreciable incidence of delayed, post-EVAR, aneurysm rupture. This was primarily a consequence of structural device failure. These failures provided important lessons for re-design and the modern ''second generation'' devices, including the Zenith (Cook Inc, Bloomington, IN, USA) endograft, are thought to be more reliable, particularly providing better fixation and sealing and also a more durable stent/fabric structure. This article comprises a review of the English literature detailing the endovascular treatment of abdominal aortic aneurysms using the Zenith endograft. It focuses on clinical studies or trials with intermediate to long-term follow-up, and related the literature to our own experience. In the series examined (N.=2 017 patients) the early mortality rate ranged from 0% to 4.1% and the technical success rate from 97.7% to 100%. The re-intervention rate was related to the length of follow-up (6.8% to 14%). Conversion rates were consistently <1%. There was a low incidence of device migration, limb thrombosis, component separation and stent fracture. These data support the ongoing use of the Zenith endovascular graft in patients with abdominal aortic aneurysms suitable for EVAR.

Protein-binding partners of the tobacco syntaxin NtSyr1.

Syntaxins and other SNARE (soluble NSF-attachment protein receptor) complex proteins play a key role in the cellular processes of vesicle trafficking, vesicle fusion and secretion. Intriguingly, the SNARE NtSyr1 (=NtSyp121) from Nicotiana tabacum also appears to have a role in signalling evoked by the plant stress hormone abscisic acid. However, partner proteins contributing to its function(s) remain unknown. We used an affinity chromatography approach to identify proteins from tobacco leaf microsomes that directly interact with the hydrophilic (cytosolic) domains of NtSyr1 and report several interacting proteins with sensitivities to the endopeptidase activity of Clostridium botulinum neurotoxins, including one protein that was recognised by alphaAtSNAP33 antiserum, raised against the Arabidopsis SNAP25 homologue. Treatment of microsomal membrane fractions indicated a protein near 55 kDa was sensitive to proteolysis by BotN/A and BotN/E, yielding degradation products of approximately 34 and 23 kDa. Expressed and purified AtSNAP33 also bound directly to the cytosolic domain of NtSyr1 and was sensitive to proteolysis by these toxins, suggesting that NtSyr1, a tobacco homologue of AtSNAP33, and coordinate SNAREs are likely to associate as partners for function in vivo.

Isolated connection of the right superior caval vein to the left atrium: non-invasive neonatal diagnosis.

Isolated anomalous drainage of the right superior caval vein to the left atrium is a very rare cause of cyanosis in the newborn. Herein, the cross-sectional echocardiography and colour Doppler findings of this malformation are described.