Haematological risk factors predicting clinical success in transarterial embolisation for acute gastrointestinal bleeding.

OBJECTIVES: Evaluate clinical outcomes in transarterial embolisation (TAE) for acute gastrointestinal bleeding (GIB) and determine risk factors for 30-day reintervention for rebleeding and mortality. METHODS: TAE cases were retrospectively reviewed between March 2010 and September 2020 at our tertiary centre. Technical success (angiographic haemostasis following embolisation) was measured. Uni- and multivariate logistic regression analysis were performed to identify risk factors for clinical success (absence of 30-day reintervention or mortality) following embolisation for active GIB or empirical embolisation for suspected bleeding. RESULTS: TAE was conducted in 139 patients (92 (66.2%) male; median age:73, range: 20-95 years) for acute upper GIB (n = 88) and lower GIB (n = 51). TAE was technically successful in 85/90 (94.4%) and clinically successful in 99/139 (71.2%); with 12 (8.6%) reintervention cases for rebleeding (median interval 2 days) and 31 (22.3%) cases of mortality (median interval 6 days). Reintervention for rebleeding was associated with haemoglobin drop > 40 g l-1 from baseline based on univariate analysis (p = 0.047). 30-day mortality was associated with pre-intervention platelet count < 150×109 l-1 (p < 0.001, OR 7.35, 95% CI 3.05-17.71) and INR > 1.4 (p < 0.001, OR 4.75, 95% CI 2.03-11.09) on multivariate logistic regression analysis. No associations were found for patient age, gender, antiplatelet/anticoagulation prior to TAE, or when comparing upper and lower GIB with 30-day mortality. CONCLUSION: TAE had excellent technical success for GIB with relatively high (1-in-5) 30-day mortality. INR > 1.4 and platelet count < 150×109 l-1 were individually associated with TAE 30-day mortality, and pre-TAE > 40 g l-1 haemoglobin decline with rebleeding requiring reintervention. ADVANCES IN KNOWLEDGE: Recognition and timely reversal of haematological risk factors may improve TAE periprocedural clinical outcomes.

Transcranial magnetic stimulation in the semi-quantitative, pre-operative assessment of patients undergoing spinal deformity surgery.

PURPOSE: To compare measurements of motor evoked potential latency stimulated either magnetically (mMEP) or electrically (eMEP) and central motor conduction time (CMCT) made pre-operatively in conscious patients using transcranial and intra-operatively using electrical cortical stimulation before and after successful instrumentation for the treatment of adolescent idiopathic scoliosis. METHODS: A group initially of 51 patients with adolescent idiopathic scoliosis aged 12-19 years was evaluated pre-operatively in the outpatients' department with transcranial magnetic stimulation. The neurophysiological data were then compared statistically with intra-operative responses elicited by transcranial electrical stimulation both before and after successful surgical intervention. MEPs were measured as the cortically evoked compound action potentials of Abductor hallucis. Minimum F-waves were measured using conventional nerve conduction methods and the lower motor neuron conduction time was calculated and this was subtracted from MEP latency to give CMCT. RESULTS: Pre-operative testing was well tolerated in our paediatric/adolescent patients. No neurological injury occurred in any patient in this series. There was no significant difference in the values of mMEP and eMEP latencies seen pre-operatively in conscious patients and intra-operatively in patients under anaesthetic. The calculated quantities mCMCT and eCMCT showed the same statistical correlations as the quantities mMEP and eMEP latency. CONCLUSIONS: The congruency of mMEP and eMEP and of mCMCT and eCMCT suggests that these measurements may be used comparatively and semi-quantitatively for the comparison of pre-, intra-, and post-operative spinal cord function in spinal deformity surgery.

Gluteal Compartment Syndrome after Fenestrated Endovascular Aortic Aneurysm Repair.

We describe a case of gluteal compartment syndrome (GCS) after a 4-vessel fenestrated endovascular abdominal aortic aneurysm repair. The case highlights the need for a high index of suspicion for GCS as a differential diagnosis for spinal cord ischemia in patients developing perioperative lower limb neurologic deficit after extensive abdominal aortic stent-graft coverage.

Effect of locally administered ciliary neurotrophic factor on the survival of transected and repaired adult sheep facial nerve.

OBJECTIVE: to determine whether the administration of Ciliary Neurotrophic Factor (CNTF) at the site of repaired facial nerve enhances regeneration in the adult sheep model. METHODS: Ten adult sheep were divided into 2 groups: control and study group (CNTF group). In the CNTF group, the buccal branch of the facial nerve was transected and then repaired by epineural sutures. CNTF was injected over the left depressor labii maxillaris muscle in the vicinity of the transected and repaired nerve for 28 days under local anesthesia. In the CNTF group, the sheep were again anesthetized after nine months and the site of facial nerve repair was exposed. Detailed electrophysiological, tension experiments and morphometric studies were carried out and then analyzed statistically. RESULTS: The skin CV min, refractory period, Jitter and tension parameters were marginally raised in the CNTF group than the control but the difference was statistically insignificant between the two groups. Morphometric indices also did not show any significant changes in the CNTF group. CONCLUSION: CNTF has no profound effect on neuronal regeneration of adult sheep animal model. KEYWORDS: CNTF; Neurtrophic factors; Sheep; Facial nerve; Regeneration.

Rare true-positive isolated SSEP loss with preservation of MEPs response during scoliosis correction.

STUDY DESIGN: Case report. OBJECTIVE: To report a case of a true-positive isolated somatosensory evoked potential (SSEP) loss with preservation of motor evoked potential (MEP) response during scoliosis correction. SUMMARY OF BACKGROUND DATA: Combined intraoperative monitoring uses SSEPs and MEPs to decrease the probability of observing false-negative events. In combination, SSEPs and MEPs have become a standard of care for spinal deformity surgery. However, literature review reveals several cases of false-negative response with combined SSEPs and MEPs, raising the contention that intraoperative monitoring does not reliably identify all isolated selective spinal cord dysfunction. METHODS: A 15-year-old female patient with a 65° right thoracic adolescent idiopathic scoliosis underwent correction and posterior spinal fusion with segmental pedicle screw instrumentation. After capture and derotation of the left concave rod, left-sided irreversible SSEP loss occurred whereas MEPs remained unchanged. After excluding systemic factors, anesthetic causes, or technical fault, deformity correction was released and instrumentation removed. No cortical breach was reported during pedicle screw removal. RESULTS: Postoperatively, no clinical sensory or motor deficit was present; computed tomography demonstrated a burst left pedicle at T10 with the medial pedicle wall fragment in direct contact with the dorsal spinal cord. Magnetic resonance imaging excluded cord edema or other evidence of injury. Three days after surgery, intraoperative monitoring showed delayed latencies and amplitudes of the left SSEP. An uneventful reinsertion of instrumentation and correction excluding the left T10 pedicle screw was performed 7 days after the initial surgery. CONCLUSION: This case report provides evidence of selective posterior spinal cord dysfunction with sparing of the anterior columns immediately after a correction maneuver and emphasizes the importance of simultaneous SSEP and MEP monitoring. To the authors' knowledge, there is no previous report of a true-positive isolated SSEP loss with preservation of MEP response during scoliosis correction. LEVEL OF EVIDENCE: N/A.

Sutureless repair of the facial nerve using biodegradable glass fabric.

OBJECTIVES/HYPOTHESIS: To compare a sutureless method of facial nerve repair using a biodegradable glass fabric with the standard method of microsurgical suture. STUDY DESIGN: The facial nerve was transected in groups of six sheep and repaired by either entubulation with a biodegradable glass fabric or standard microsurgical epineurial suture repair. METHODS: Both methods of repair were compared with each other and with a normal control group using electrophysiological and morphometric analysis. RESULTS: Maximum conduction velocity, axon and fiber diameter, and myelin-sheath thickness were all reduced in the repaired nerves when compared with the normal nerves. There was no significant difference among any of the outcome variables between the repair groups. CONCLUSIONS: Repair of nerve injuries by entubulation has several theoretical advantages over standard suture repair: less trauma to nerve ends, no need for microsurgical skills, and delivery of neurotrophic growth factors. It is concluded that repair of the facial nerve by glass-wrap entubulation offers an alternative to standard suture repair without the demands of microsurgery on both time and surgical expertise.

Endovascular management of delayed complete graft thrombosis after endovascular aneurysm repair.

Graft thrombosis rates after endovascular aneurysm repair (EVAR) of abdominal aortic aneurysms vary widely in published series. When thrombosis does occur, it usually involves a single limb and occurs within 3 months of stent-graft insertion. If the entire endoprosthesis is thrombosed, treatment may be challenging because femoro-femoral crossover graft insertion is not an option and a greater volume of thrombus is present, thus making thrombolysis more difficult. We present two cases of delayed thrombosis after EVAR involving the entire stent-graft. These were successfully treated by a combined surgical and endovascular technique, and patency has been maintained in both cases to date.

Cardiovascular and autonomic nervous effects of edrophonium and atropine combinations during neuromuscular blockade antagonism in sheep.

OBJECTIVE: To study heart rate (HR), arterial blood pressure (BP) and autonomic nervous (AN) effects of edrophonium-atropine combinations during neuromuscular blockade (NMB) antagonism in sheep. EXPERIMENTAL DESIGN: Randomized, prospective and experimental study. ANIMALS: Seventy-eight Scottish blackface ewes; mean age: 4.5 years; mean body mass: 54 kg. METHODS: After induction with IV etomidate (0.5 mg kg(-1)) and midazolam (0.5 mg kg(-1)), anaesthesia was maintained with halothane and NMB produced with atracurium or mivacurium. In the first study (n = 53), the electrocardiographic (ECG), HR, BP and AN effects of low (40 microg kg(-1)) and high (80 microg kg(-1)) atropine doses combined with either of two edrophonium doses (0.5 or 1.0 mg kg(-1)) were investigated. These variables were also measured in a second study when edrophonium (1.0 mg kg(-1)) was administered 5 minutes before atropine (80 microg kg(-1)) and vice versa. Data were analysed using one-way within-subjects and repeated measures anova. RESULTS: In the first study, all combinations reversed NMB but significantly (p < 0.001) increased HR and BP within 2 minutes without arrhythmias. In the second study, edrophonium (1.0 mg kg(-1)) significantly increased HR and BP, saliva flow (n = 1) and lung sounds (n = 3) and caused ECG changes (n = 1). Cardiovascular changes were partially reversed by atropine (80 microg kg(-1)) administered 5 minutes later. Administered first, atropine (80 microg kg(-1)) significantly decreased HR and BP effects which were fully (HR) and partially (BP) reversed by edrophonium (1 mg kg(-1)) administered 5 minutes later. CONCLUSION AND CLINICAL RELEVANCE: The cardiovascular effects of edrophonium and atropine were opposite to those reported in humans and dogs. Edrophonium (0.5 mg kg(-1)) and atropine (80 microg kg(-1)) caused the mildest HR changes without ECG and noncardiac AN disturbances, and is recommended for the antagonism of NMB in sheep.

Lung function in congenital kyphosis and kyphoscoliosis.

OBJECTIVE: To quantify the respiratory compromise in patients with a congenital kyphosis or kyphoscoliosis in whom the major deformity is the kyphosis. METHODS: Forty-one patients with congenital vertebral anomalies resulting in a kyphosis or kyphoscoliosis, in which the kyphosis was the major deformity, and requiring spine surgery were studied retrospectively. The preoperative respiratory function and radiographic spinal assessments were compared. RESULTS: Twenty-two patients (54%) had an impairment of respiratory function: 2 patients (5%) were severely affected, 8 patients (20%) were moderately affected, and 12 patients (29%) were mildly affected. CONCLUSIONS: An increasing severity of kyphosis was associated with a significant increase in respiratory impairment (P<0.005). A more cranial level of the kyphosis, especially above T10, had a significantly greater effect on respiratory impairment (P<0.001). One untreated patient with a severe kyphosis (128 degrees) died from cor pulmonale.

Use of a static magnetic field to promote recovery after peripheral nerve injury.

OBJECT: While pulsed electromagnetic stimulation has been shown to enhance peripheral nerve regeneration, the effect of a static magnetic field on nerve repair is less clear. The aim of this study was to establish what effect an imposed exogenous static magnetic field has on peripheral nerve regeneration after transection and repair. METHODS: Three groups of six adult sheep were used. The first group acted as normal controls. In the second group, the median nerve was divided and immediately repaired by entubulation within a "controlled-release" biodegradable glass tube. In the third group, small magnets were applied to the sides of the biodegradable glass tubes before the median nerve was repaired using these magnetic tubes. The sheep were allowed to recover and were reexamined 10 months later. The animals underwent comprehensive morphometric (cross-sectional morphometry and measurement of internodal lengths), electrophysiological (determinations of stimulated jitter, maximum conduction velocity, refractory period, and F waves), and isometric tension (isometric twitch and tetanic tension) assessments. CONCLUSIONS: Exogenously applied static electromagnetic fields do not enhance peripheral nerve regeneration.

An in vivo study of peripheral nerves in continuity: biomechanical and physiological responses to elongation.

Using an animal model, the in vivo visco-elastic properties of peripheral nerve in continuity were examined. The nerves were stretched by either 1 cm - Group A (8.8% strain) or 2 cm - Group B (16.1% strain). At constant strain, the stress-relaxation curves were plotted. Maximal relaxation was observed in the first 20 min. After 1 h, the decrease in tensions in Groups A and B were 36.8% and 41.8%, respectively. Throughout this hour and for 30 min after the release of tension, regular recordings of nerve blood flow using laser doppler flowmetry and peak nerve conduction velocity were taken. Nerve blood flow was reduced by similar amounts (Group A, 70%; Group B, 78%) by application of traction. On release, however, Group A displayed a reactive hyperaemia (blood flow 151% starting value) while Group B failed to recover (50% starting value at 30 min). Peak nerve conduction velocity was not significantly altered in Group A in response to traction, whereas in Group B the result was a gradual, but significant reduction in peak velocity to 66% starting value. The lack of correlation between blood flow and peak nerve conduction velocity in these studies suggests that ischaemia is not solely responsible for the increased latency.