Unilateral posterior cervical spinal cord infarction due to spontaneous vertebral artery dissection

Context

Ischemia of the cervical spinal cord is a rare complication of spontaneous vertebral artery dissection (VAD) and usually involves the ventral portion. We describe a less evocative clinical presentation and images of unilateral posterior spinal cord infarction due to spontaneous VAD in order to facilitate early diagnosis.

Findings

A previously fit 30-year-old man presented with persistent headaches and proximal motor deficit of the right arm. He was diagnosed with spontaneous dissection of both vertebral arteries, with occlusion of the right one, and the right carotid artery. Neurological examination also revealed a right C2–C3 tactile sensory loss, with unilateral proprioceptive deficit below. Brain images revealed small bilateral cerebellar infarcts which could not be responsible for the clinical symptoms. Magnetic resonance imaging of the spinal cord showed a right posterior cervical spinal cord infarction. The patient achieved nearly complete recovery after several weeks of anticoagulation and rehabilitation.

Conclusion and clinical relevance

Infarction of the caudal portion of the cervical spinal cord, especially unilateral, caused by spontaneous VAD, has rarely been described and is certainly under-diagnosed due to less suggestive symptoms, like unilateral and mainly sensory deficit. Nevertheless, early diagnosis of this condition is important to guide patient management and rehabilitation.     

Pregnancy-associated plasma protein A in non-cardiac conditions

ObjectivePAPP-A is a promising new marker in coronary heart disease. It is important to investigate its specificity in order to establish its clinical utility as a marker of coronary heart disease.Design and methodsPAPP-A was measured within 24 h following hospital admission in 1448 consecutive patients admitted with diagnoses other than acute coronary syndromes.ResultsPAPP-A was detectable (≥ 4.0 mIU/L) in 278 (19.2%) patients, among whom the mean level was 6.3 mIU/L (95% C.I., 6.1–6.5 mIU/L). The 95 and 99 percentiles for PAPP-A were 7.3 and 9.4 mIU/L, respectively. There was no difference in the mean PAPP-A of different diagnoses (p = 0.33). None of the specific diagnoses known to influence established coronary markers appeared to influence the level of circulating PAPP-A.ConclusionPAPP-A is low in patients without known coronary heart disease. PAPP-A levels seem to be a potentially highly specific marker for heart disease.     

Vertebral artery injuries in cervical spine surgery

Background contextVertebral artery injuries (VAIs) are rare but serious complications of cervical spine surgery, with the potential to cause catastrophic bleeding, permanent neurologic impairment, and even death. The present literature regarding incidence of this complication largely comprises a single surgeon or small multicenter case series.PurposeWe sought to gather a large sample of high-volume surgeons to adequately characterize the incidence and risk factors for VAI, management strategies used, and patient outcomes after VAI.Study designThe study was constructed as a cross-sectional study comprising all cervical spine patients operated on by the members of the international Cervical Spine Research Society (CSRS).Patient sampleAll patients who have undergone cervical spine surgery by a current member of CSRS as of the spring of 2012.Outcome measuresFor each surgeon surveyed, we collected self-reported measures to include the number of cervical cases performed in the surgeon's career, the number of VAIs encountered, the stage of the case during which the injury occurred, the management strategies used, and the overall patient outcome after injury.MethodsAn anonymous 10-question web-based survey was distributed to the members of the CSRS. Statistical analysis was performed using Student t tests for numerical outcomes and chi-squared analysis for categorical variables.ResultsOne hundred forty-one CSRS members (of 195 total, 72%) responded to the survey, accounting for a total of 163,324 cervical spine surgeries performed. The overall incidence of VAI was 0.07% (111/163,324). Posterior instrumentation of the upper cervical spine (32.4%), anterior corpectomy (23.4%), and posterior exposure of the cervical spine (11.7%) were the most common stages of the case to result in an injury to the vertebral artery. Discectomy (9%) and anterior exposure of the spine (7.2%) were also common time points for an arterial injury. One-fifth (22/111) of all VAI involved an anomalous course of the vertebral artery. The most common management of VAI was by direct tamponade. The outcomes of VAIs included no permanent sequelae in 90% of patients, permanent neurologic sequelae in 5.5%, and death in 4.5%. Surgeons at academic and private centers had nearly identical rates of VAIs. However, surgeons who had performed 300 or fewer cervical spine surgeries in their career had a VAI incidence of 0.33% compared with 0.06% in those with greater than 300 lifetime cases (p=.028).ConclusionsThe overall incidence of VAI during cervical spine surgery reported from this survey was 0.07%. Less experienced surgeons had a higher rate of VAI compared with their more experienced peers. The results of VAI are highly variable, resulting in no permanent harm most of the time; however, permanent neurologic injury or death occur in 10% of cases.     

Anaesthesia for obesity surgery

The aim of this article is to give a brief but comprehensive overview of the current management of the patient undergoing bariatric (weight loss) surgery. This article will discuss the different types of obesity surgery commonly performed, and the practical aspects of how to manage these patients both perioperatively and postoperatively. The principles described can be utilised in the management of obese patients attending for other types of surgery.     

Biomechanical and anatomical considerations in lumbar spinous process fixation—an in vitro human cadaveric model

Background contextAlthough multiple mechanisms of device attachment to the spinous processes exist, there is a paucity of data regarding lumbar spinous process morphology and peak failure loads.PurposeUsing an in vitro human cadaveric spine model, the primary objective of the present study was to compare the peak load and mechanisms of lumbar spinous process failure with variation in spinous process hole location and pullout direction. A secondary objective was to provide an in-depth characterization of spinous process morphology.Study designBiomechanical and anatomical considerations in lumbar spinous process fixation using an in vitro human cadaveric model.MethodsA total of 12 intact lumbar spines were used in the current investigation. The vertebral segments (L1–L5) were randomly assigned to one of five treatment groups with variation in spinous process hole placement and pullout direction: (1) central hole placement with superior pullout (n=10), (2) central hole placement with inferior pullout (n=10), (3) inferior hole placement with inferior pullout (n=10), (4) superior hole placement with superior pullout (n=10), and (5) intact spinous process with superior pullout (n=14). A 4-mm diameter pin was placed through the hole followed by pullout testing using a material testing system. As well, the bone mineral density (BMD) (g/cm³) was measured for each segment. Data were quantified in terms of anatomical dimensions (mm), peak failure loads (newtons [N]), and fracture mechanisms, with linear regression analysis to identify relationships between anatomical and biomechanical data.ResultsBased on anatomical comparisons, there were significant differences between the anteroposterior and cephalocaudal dimensions of the L5 spinous process versus L1–L4 (p<.05). Statistical analysis of peak load at failure of the four reconstruction treatments and intact condition demonstrated no significant differences between treatments (range, 350–500 N) (p>.05). However, a significant linear correlation was observed between peak failure load and anteroposterior and cephalocaudal dimensions (p<.05). Correlation between BMD and peak spinous processes failure load was approaching statistical significance (p=.08). 30 of 54 specimens failed via direct pullout (plow through), whereas 8 of 54 specimens demonstrated spinous process fracture. The remaining cases failed via plow through followed by fracture of the spinous process (16 of 54; 29%).ConclusionsThe present study demonstrated that variation in spinous process hole placement did not significantly influence failure load. However, there was a strong linear correlation between peak failure load and the anteroposterior and cephalocaudal anatomical dimensions. From a clinical standpoint, the findings of the present study indicate that attachment through the spinous process provides a viable alternative to attachment around the spinous processes. In addition, the anatomical dimensions of the lumbar spinous processes have a greater influence on biomechanical fixation than either hole location or BMD.     

Isolated, spontaneous superior mesenteric and celiac artery dissection: case report and review of literature

Spontaneous, isolated dissection of the superior mesenteric artery (SMA) and celiac artery (CA) is rare. Although there are known risk factors, there is no particular mechanism that is common to vascular dissections. The objectives of this study were to review the current literature on diagnosis and treatment of isolated SMA and CA dissection, and to review aortic complications in giant cell arteritis, Takayasu arteritis, and polyarteritis nodosa. Giant cell arteritis, Takayasu arteritis, and polyarterteritis nodosa are vasculitides that are associated with SMA and CA dissection. An interesting aspect of this case is that the patient was a healthy person before presentation, and ultimately, did not have an underlying etiology to explain the dissection. In addition, the patient was successfully managed without operative intervention. Although there are known risk factors in patients who present with isolated, spontaneous SMA and CA dissection, the pathogenesis is still unclear. The prognosis has improved significantly with the early use of computed tomography angiography to diagnosis this entity. Although most cases require surgical intervention, there are some, as in this case, that are managed non-operatively.     

Atrial and brain natriuretic peptide concentrations and the response to inhaled nitric oxide in patients with acute respiratory distress syndrome

Purpose

The response to inhaled nitric oxide (iNO) is inconsistent in patients with acute respiratory distress syndrome (ARDS). We sought to determine whether the response to iNO, defined as 20% Pao₂/Fio₂ increase from baseline, depends on the level of cardiac natriuretic peptides.

Materials and methods

This is a prospective cohort study including 11 consecutive patients with ARDS who were eligible to receive iNO. Measurements of plasma concentrations of atrial natriuretic peptide (ANP), N-Terminal-Pro-B-Type Natriuretic Peptide (NT-pro-BNP) and 3′,5′-cyclic guanosine monophosphate were obtained before initiating iNO and 30 minutes later during iNO. Baseline cardiac peptides, oxygenation, and hemodynamic variables and their change during iNO were compared among responders and nonreponders to iNO.

Results

Baseline ANP and NT-pro-BNP concentrations were higher in patients that responded to iNO and tended to decrease during iNO in responders only. 3′,5′-Cyclic guanosine monophosphate concentrations were not different among responders and nonresponders and were unchanged during iNO. Baseline ANP was strongly correlated with change in intrapulmonary shunt, and baseline NT-pro-BNP and its change were correlated with the change in cardiac output.

Conclusions

High ANP and NT-pro-BNP concentrations are associated with the response to iNO. These data suggest that cardiac peptides have the potential to identify a subgroup of patients with ARDS who might derive clinical benefit from iNO.