Development of a Pedicle Screw Fixation Simulation Model for Surgical Training Using a 3-Dimensional Printer.

OBJECTIVE: Training surgeons in pedicle screw fixation (PSF) techniques during actual surgery is limited because of patient safety, complications, and surgical efficiency issues. Recent technical developments are leading the world to an era of personalized three-dimensional (3D) printing. This study aimed to evaluate the educational effect of using a 3D-printed spine model to train beginners in PSF techniques to improve screw accuracy and procedure time. METHODS: Computed tomography (CT) scan data were used in a 3D printer to produce a life-size lumbar spine replica of L1-3 vertebrae. Four residents performed PSF thrice. Each resident performed 18 screw fixations on both sides (6 screws per trial). The time to complete the procedure and pedicle violation was recorded. RESULTS: The average time for the 3 procedures was 42.1±2.9 minutes, 38.8±3.3 minutes, and 32.1±2.5 minutes, respectively. Furthermore, the average pedicle screw score for the 3 procedures was 13.0±0.8, 14.5±0.6, and 16.0±0.8, respectively. As the trial was repeated, the procedure time decreased and the accuracy of screw fixation tended to be more accurate. CONCLUSIONS: It was possible to decrease the procedure time and increase accuracy through repeated training using the 3D-printed spine model. By implementing a 3Dprinted spine model based on the patient's actual CT data, surgeons can perform simulation surgery before the actual surgery. Therefore, this technology can be useful in educating residents to improve their surgical skills.

Difference in the Cobb Angle Between Standing and Supine Position as a Prognostic Factor After Vertebral Augmentation in Osteoporotic Vertebral Compression Fractures.

OBJECTIVE: We retrospectively analyzed patients with osteoporotic vertebral compression fracture (OVCF) undergoing vertebral augmentation to compare the Cobb angle changes in the supine and standing positions and the clinical outcomes. METHODS: We retrospectively extracted the data of OVCF patients who underwent vertebral augmentation. Back pain was assessed using a visual analogue scale (VAS). Supine and standing radiographs were assessed before treatment to determine the Cobb angle and compression ratio. Receiver operating characteristic curve analysis was performed to determine the optimal cutoff to predict favorable outcomes after vertebral augmentation. RESULTS: A total of 249 patients were included. We observed a statistically significant increase in the VAS score change with increasing Cobb angle and compression ratio (p < 0.001), and multivariate logistic regression analysis showed that a difference in the Cobb angle (odds ratio [OR], 1.27) and compression ratio (OR, 1.12) were the independent risk factors for predicting short-term favorable outcomes after vertebral augmentation. In addition, we found that the difference in the Cobb angle (OR, 1.05) was the only factor for predicting midterm favorable outcomes after vertebral augmentation. The optimal cutoff value of the difference in the Cobb angle for predicting midterm favorable outcomes was 35.526°. CONCLUSION: We found that the midterm clinical outcome after vertebral augmentation was better when there was a difference of approximately 35% or more in the Cobb angle between the standing and supine positions. Surgeons should pay attention to the difference in the Cobb angle depending on the posture when deciding to perform vertebral augmentation in patients with OVCFs.

Impact of Off-Hour Hospital Presentation on Mortality in Different Subtypes of Acute Stroke in Korea : National Emergency Department Information System Data.

OBJECTIVE: Several studies have reported inconsistent findings among countries on whether off-hour hospital presentation is associated with worse outcome in patients with acute stroke. However, its association is yet not clear and has not been thoroughly studied in Korea. We assessed nationwide administrative data to verify off-hour effect in different subtypes of acute stroke in Korea. METHODS: We respectively analyzed the nationwide administrative data of National Emergency Department Information System in Korea; 7144 of ischemic stroke (IS), 2424 of intracerebral hemorrhage (ICH), and 1482 of subarachnoid hemorrhage (SAH), respectively. "Off-hour hospital presentation" was defined as weekends, holidays, and any times except 8:00 AM to 6:00 PM on weekdays. The primary outcome measure was in-hospital mortality in different subtypes of acute stroke. We adjusted for covariates to influence the primary outcome using binary logistic regression model and Cox's proportional hazard model. RESULTS: In subjects with IS, off-hour hospital presentation was associated with unfavorable outcome (24.6% off hours vs. 20.9% working hours, p<0.001) and in-hospital mortality (5.3% off hours vs. 3.9% working hours, p=0.004), even after adjustment for compounding variables (hazard ratio [HR], 1.244; 95% confidence interval [CI], 1.106-1.400; HR, 1.402; 95% CI, 1.124-1.747, respectively). Off-hours had significantly more elderly ≥65 years (35.4% off hours vs. 32.1% working hours, p=0.029) and significantly more frequent intensive care unit admission (32.5% off hours vs. 29.9% working hours, p=0.017) than working hours. However, off-hour hospital presentation was not related to poor short-term outcome in subjects with ICH and SAH. CONCLUSION: This study indicates that off-hour hospital presentation may lead to poor short-term morbidity and mortality in patients with IS, but not in patients with ICH and SAH in Korea. Excessive death seems to be ascribed to old age or the higher severity of medical conditions apart from that of stroke during off hours.

Effects of statin and deferoxamine administration on neurological outcomes in a rat model of intracerebral hemorrhage.

Deferoxamine (DFX), a potent iron-chelating agent, reduces brain edema and neuronal cell injury that develop due to the hemolysis cascade. Statins have neuroprotective effects via anti-inflammatory action and increment of cerebral blood flow after intracerebral hemorrhage (ICH). The purpose of this study was to identify the effects of combined DFX and statins treatment in an experimental ICH rat model. The treatments were: intraperitoneal (i.p.) injection of DFX (group I), combined treatment of i.p. DFX and oral statins (group II), statins only (group III) and treatment with vehicle (group IV). Induction of ICH was performed with injection of bacterial collagenase type IV into the left striatum. After removal of the brain, hematoma volume, water content and brain atrophy were measured. Immunohistochemistry in the perihematomal region was performed for identification of microglial infiltration, astrocyte expression and apoptotic cell presence. Statistical analysis was performed using the non-parametric Kruskal-Wallis test and significance was evaluated when the p value was less than 0.05. According to behavioral tests, significant differences among treatment groups were noted 4 weeks after ICH induction (p < 0.05). However, there were no significant differences among treatment groups in hematoma volume, brain water content or brain atrophy. In the perihematomal area, the activated microglial cells were reduced in the combined treatment group. Among the four groups, a significant difference in immunohistochemical staining was identified (p < 0.05). These results suggest that combined treatment with DFX and statins improves neurologic outcomes after ICH through reduction of microglial infiltration, apoptosis, inflammation and brain edema.

Prior use of 3-hydroxy-3-methyl-glutaryl-coenzyme a reductase inhibitor, simvastatin fails to improve outcome after experimental intracerebral hemorrhage.

OBJECTIVE: Contrary to some clinical belief, there were quite a few studies regarding animal models of intracerebral hemorrhage (ICH) in vivo suggesting that prior use of statins may improve outcome after ICH. This study reports the effect of 3-hydroxy-3-methyl-glutaryl-coenzyme A (HMG CoA) reductase inhibitor, simvastatin given before experimental ICH. METHODS: Fifty-one rats were subjected to collagenase-induced ICH, subdivided in 3 groups according to simvastatin treatment modality, and behavioral tests were done. Hematoma volume, brain water content and hemispheric atrophy were analyzed. Immunohistochemical staining for microglia (OX-42) and endothelial nitric oxide synthase (eNOS) was performed and caspase-3 activity was also measured. RESULTS: Pre-simvastatin therapy decreased inflammatory reaction and perihematomal cell death, but resulted in no significant reduction of brain edema and no eNOS expression in the perihematomal region. Finally, prior use of simvastatin showed less significant improvement of neurological outcome after experimental ICH when compared to post-simvastatin therapy. CONCLUSION: The present study suggests that statins therapy after ICH improves neurological outcome, but prior use of statins before ICH might provide only histological improvement, providing no significant impact on neurological outcome against ICH.

Impact of early enteral nutrition on in-hospital mortality in patients with hypertensive intracerebral hemorrhage.

OBJECTIVE: We conducted this study to evaluate the clinical impact of early enteral nutrition (EN) on in-hospital mortality and outcome in patients with critical hypertensive intracerebral hemorrhage (ICH). METHODS: We retrospectively analyzed 123 ICH patients with Glasgow Coma Scale (GCS) score of 3-12. We divided the subjects into two groups : early EN group (< 48 hours, n = 89) and delayed EN group (≥ 48 hours, n = 34). Body weight, total intake and output, serum albumin, C-reactive protein, infectious complications, morbidity at discharge and in-hospital mortality were compared with statistical analysis. RESULTS: The incidence of nosocomial pneumonia and length of intensive care unit stay were significantly lower in the early EN group than in the delayed EN group (p < 0.05). In-hospital mortality was less in the early EN group than in the delayed EN group (10.1% vs. 35.3%, respectively; p = 0.001). By multivariate analysis, early EN [odds ratio (OR) 0.229, 95% CI : 0.066-0.793], nosocomial pneumonia (OR = 5.381, 95% CI : 1.621-17.865) and initial GCS score (OR = 1.482 95% CI : 1.160-1.893) were independent predictors of in-hospital mortality in patients with critical hypertensive ICH. CONCLUSION: These findings indicate that early EN is an important predictor of outcome in patients with critical hypertensive ICH.

Impact of cardio-pulmonary and intraoperative factors on occurrence of cerebral infarction after early surgical repair of the ruptured cerebral aneurysms.

OBJECTIVE: Delayed ischemic deficit or cerebral infarction is the leading cause of morbidity and mortality after aneurysmal subarachnoid hemorrhage (SAH). The purpose of this study is to reassess the prognostic impact of intraoperative elements, including factors related to surgery and anesthesia, on the development of cerebral infarction in patients with ruptured cerebral aneurysms. METHODS: Variables related to surgery and anesthesia as well as predetermined factors were all evaluated via a retrospective study on 398 consecutive patients who underwent early microsurgery for ruptured cerebral aneurysms in the last 7 years. Patients were dichotomized as following; good clinical grade (Hunt-Hess grade I to III) and poor clinical grade (IV and V). The end-point events were cerebral infarctions and the clinical outcomes were measured at postoperative 6 months. RESULTS: The occurrence of cerebral infarction was eminent when there was an intraoperative rupture, prolonged temporary clipping and retraction time, intraoperative hypotension, or decreased O(2) saturation, but there was no statistical significance between the two different clinical groups. Besides the Fisher Grade, multiple logistic regression analyses showed that temporary clipping time, hypotension, and low O(2) saturation had odds ratios of 1.574, 3.016, and 1.528, respectively. Cerebral infarction and outcome had a meaningful correlation (gamma=0.147, p=0.038). CONCLUSION: This study results indicate that early surgery for poor grade SAH patients carries a significant risk of ongoing ischemic complication due to the brain's vulnerability or accompanying cardio-pulmonary dysfunction. Thus, these patients should be approached very cautiously to overcome any anticipated intraoperative threat by concerted efforts with neuro-anesthesiologist in point to point manner.