Preoperative Ionized Magnesium Levels and Risk of Acute Kidney Injury After Cardiac Surgery.

RATIONALE & OBJECTIVE: Although postoperative acute kidney injury (AKI) is a serious complication after cardiac surgery, preventive measures are limited. Despite the known association of preoperative low magnesium levels with cardiac surgery-related atrial fibrillation, the association between preoperative magnesium concentration and postoperative AKI has not been fully elucidated. This study evaluated the association between preoperative serum magnesium level and the development of AKI after cardiac surgery. STUDY DESIGN: Retrospective observational cohort study. SETTING & PARTICIPANTS: Patients aged≥18 years who underwent cardiac surgery at 2 South Korean tertiary hospitals between 2006 and 2020 were identified from medical records. Patients with missing information, an estimated glomerular filtration rate<15mL/min/1.73m2, receiving maintenance dialysis, or a history of AKI treated by dialysis within 1 year before surgery were excluded. EXPOSURE: Preoperative serum magnesium levels. OUTCOME: Postoperative AKI within 48 hours after surgery, defined using the Acute Kidney Injury Network (AKIN) criteria, and dialysis-treated AKI within 30 days after surgery. ANALYTICAL APPROACH: Multivariable logistic regression analysis. RESULTS: Among the 9,766 patients (median age, 64.0 years; 60.1% male), postoperative AKI and dialysis-treated AKI were observed in 40.1% and 4.3% patients, respectively. Postoperative AKI was more prevalent in patients with lower serum magnesium levels (44.9%, 41.4%, 39.4%, and 34.8% in quartiles 1-4, respectively). Multivariable logistic regression analysis revealed that the odds ratios (ORs) for postoperative AKI were progressively larger across progressively lower quartiles of serum magnesium concentration (adjusted ORs of 1.53 [95% CI, 1.33-1.76], 1.29 [95% CI, 1.12-1.48], 1.15 [95% CI, 1.01-1.31] for quartiles 1-3, respectively, relative to quartile 4, P for trend<0.001). Preoperative hypomagnesemia (serum magnesium level<1.09mg/dL) was also significantly associated with AKI (adjusted OR, 1.39 [95% CI, 1.10-1.77]) and dialysis-treated AKI (adjusted OR, 1.67 [95% CI, 1.02-2.72]). LIMITATIONS: Causality could not be evaluated in this observational study. CONCLUSIONS: Lower serum magnesium levels were associated with a higher incidence of AKI in patients undergoing cardiac surgery.

Significance of Multimodal Intraoperative Monitoring During Surgery in Patients with Craniovertebral Junction Pathology.

OBJECTIVE: Although many studies have investigated the benefits of multimodal intraoperative monitoring (MIOM) during cervical spine surgery, the benefits of MIOM in craniovertebral junction (CVJ) surgery remain unclear. The objectives of the present study were to report our clinical experience in CVJ surgery with the use of MIOM and to identify risk factors that could affect MIOM changes during surgery of CVJ pathology. METHODS: We reviewed the MIOM records of 146 patients who had undergone high cervical spinal surgery. The patients were grouped by the MIOM data recorded during surgery; the patients were included in either the MIOM or non-MIOM change group. The analyzed risk factors included demographic, myelopathy, preoperative Japanese Orthopedic Association (JOA) score, spinal cord diameter, and surgical factors. Univariate and multivariate analyses were performed to identify the risk factors for changes in MIOM data during surgery and postoperative neurological deficits. RESULTS: Our results revealed that the incidence of postoperative neurological complications was 4.1% after CVJ surgery; this rate was significantly greater in the MIOM change group than in the non-MIOM change group (21.7% vs. 0.8%; P < 0.01). Multiple regression analysis revealed that preoperative myelopathy, preoperative JOA score, and congenital anomaly/tumor were independently associated with MIOM changes during surgery. CONCLUSIONS: Postoperative neurological complications are not uncommon after CVJ surgery, and the incidence was significantly greater in the MIOM change group. Preoperative myelopathy, preoperative JOA score, and CVJ pathology related to congenital anomaly or tumor were independent risk factors for changes in MIOM data during surgery.

Comparison of Morphological Characteristics of the Subaxial Cervical Spine between Athetoid Cerebral Palsy and Normal Control.

OBJECTIVE: To compare the morphometry of subaxial cervical spine between cerebral palsy (CP) and normal control. METHODS: We retrospectively analyzed 72 patients with CP, as well as 72 patients from normal population. The two groups were matched for age, sex, and body mass index. Pedicle, lateral mass (LM), and vertebral foramen were evaluated using computed tomography (CT) imaging. Pedicle diameter, LM height, thickness, width and vertebral foramen asymmetry (VFA) were measured and compared between the two groups. Cervical dynamic motion, disc and facet joint degeneration were investigated. Additionally, we compared the morphology of LM between convex side and concave side with cervical scoliotic CP patients. RESULTS: LM height was smaller in CP group. LM thickness and width were larger in CP group at mid-cervical level. In 40 CP patients with cervical scoliosis, there were no height and width differences between convex and concave side. Pedicle outer diameter was not statistically different between two groups. Pedicle inner diameter was significantly smaller in CP group. Pedicle sclerosis was more frequent in CP patients. VFA was larger in CP group at C3, C4, and C5. Disc/facet degeneration grade was higher in the CP group. Cervical motion of CP group was smaller than those of the control group. CONCLUSION: LM morphology of CP patients was different from normal population. Sclerotic pedicles and vertebral foramen asymmetry were more commonly identified in CP patients. CP patients were more likely to demonstrate progressive disc/facet degeneration. This data may provide useful information on cervical posterior instrumentation in CP patients.

Risk factor analysis and decision-making of surgical strategy for V3 segment anomaly: significance of preoperative CT angiography for posterior C1 instrumentation.

BACKGROUND CONTEXT: Awareness of vascular anomalies is crucial to avoid iatrogenic injuries during surgical procedure. Although V3 segment anomaly has been well described, the incidence of V3 segment anomaly has been rather variable in the literature, and there are few reports regarding the adequate surgical strategy for each type of V3 segment anomaly. PURPOSE: This study aimed to analyze the incidence of V3 segment anomaly and demonstrate the importance of recognizing vertebral artery (VA) anomaly in deciding the surgical strategy for C1 screw placement. STUDY DESIGN: A retrospective cohort study was carried out. PATIENT SAMPLE: The sample included 147 patients who underwent C1 posterior instrumentation and preoperative three-dimensional computed tomography angiography (3D CTA). OUTCOME MEASURES: The primary outcome of this study was the incidence of V3 segment anomaly using preoperative CTA, and the secondary outcome was the risk factor analysis of the V3 segment anomaly. METHODS: There were 147 patients who underwent C1 posterior instrumentation to treat various kinds of upper cervical disease. The 3D CTA of the patients were assessed preoperatively to identify the anomaly of the VA. Each surgical technique of C1 posterior instrumentation was decided upon the shape and the course of the VA around the atlas. RESULTS: During the study period, 11 cases of V3 segment anomaly (7.5%) were found on 3D CTA. Persistent intersegmental artery was found in nine cases and was the most common variant of VA anomaly. Early branch of posterior inferior cerebellar artery was found in three cases. Most of V3 segment anomaly was found unilaterally, but there were two cases with bilateral V3 anomaly. Seven cases (63.6%) were associated with congenital bony abnormality around craniovertebral junction (CVJ), such as occipital assimilation, Klippel-Feil syndrome, and os odontoideum. V3 segment anomaly was significantly common in the cases with bony abnormality (29.2% (7/24) vs. 3.6% (4/123), p<.05). Compared with patient without bony abnormality, the odds ratio was 10.78 (95% CI: 2.88-40.37) for those with congenital bony abnormalities. Rheumatoid arthritis was not a risk factor of V3 segment anomaly (p=.391). CONCLUSIONS: The course of the VA is heterogenous, and the V3 segment anomaly of the VA is more common in the cases with congenital bony abnormalities around CVJ. Therefore, preoperative radiological studies should be performed to identify V3 segment variations and reduce the risk of VA injury. To avoid significant morbidities associated with VA, surgical technique of C1 posterior instrumentation should be decided depending upon the V3 segment anomaly. A more optimal entry point and trajectory for C1 fixation can be selected.

Analysis of measurement accuracy for craniovertebral junction pathology : most reliable method for cephalometric analysis.

OBJECTIVE: This study was designed to determine the most reliable cephalometric measurement technique in the normal population and patients with basilar invagination (BI). METHODS: Twenty-two lateral radiographs of BI patients and 25 lateral cervical radiographs of the age, sex-matched normal population were selected and measured on two separate occasions by three spine surgeons using six different measurements. Statistical analysis including intraclass correlation coefficient (ICC) was carried out using the SPSS software (V. 12.0). RESULTS: Redlund-Johnell and Modified (M)-Ranawat had a highest ICC score in both the normal and BI groups in the inter-observer study. The M-Ranawat method (0.83) had a highest ICC score in the normal group, and the Redlund-Johenll method (0.80) had a highest ICC score in the BI group in the intra-observer test. The McGregor line had a lowest ICC score and a poor ICC grade in both groups in the intra-observer study. Generally, the measurement method using the odontoid process did not produce consistent results due to inter and intra-observer differences in determining the position of the odontoid tip. Opisthion and caudal point of the occipital midline curve are somewhat ambiguous landmarks, which induce variable ICC scores. CONCLUSION: On the contrary to other studies, Ranawat method had a lower ICC score in the inter-observer study. C2 end-plate and C1 arch can be the most reliable anatomical landmarks.