Guideline for the management of long tunnelled external ventricular drains in chronic hydrocephalus

Modified ventriculoperitoneal shunt applied to temporary external ventricular drainage

External ventricular drainage (EVD) is a common procedure in neurosurgical practice. Presently, the three methods used most often include direct EVD (dEVD), long-tunneled external ventricular drains (LTEVDs), and EVD via the Ommaya reservoir (EVDvOR). But they possess drawbacks such as limited duration of retention, vulnerability to iatrogenic secondary infections, and challenges in regulating drainage flow. This study aimed to explore the use of a modified ventriculoperitoneal shunt (mVPS)-the abdominal end of the VPS device was placed externally-as a means of temporary EVD to address the aforementioned limitations. This retrospective cohort study, included 120 cases requiring EVD. dEVD was performed for 31 cases, EVDvOR for 54 cases (including 8 cases with previously performed dEVD), and mVPS for 35 cases (including 6 cases with previously performed EVDvOR). The one-time success rate (no need for further other EVD intervention) for dEVD, EVDvOR, and mVPS were 70.97%, 88.89%, and 91.42%, dEVD vs EVDvOR (P < 0.05), dEVD vs mVPS (P < 0.05), EVDvOR vs mVPS (P > 0.05). Puncture needle displacement or detachment was observed in nearly all cases of EVDvOR, while no such complications have been observed with mVPS. Apart from this complication, the incidence of postoperative complications was 35.48%, 14.81%, and 8.5%, dEVD vs EVDvOR (P < 0.05), dEVD vs mVPS (P < 0.05), EVDvOR vs mVPS (P > 0.05). Mean postoperative retention for EVD was 14.68 ± 9.50 days, 25.96 ± 15.14 days, and 82.43 ± 64.45 days, respectively (P < 0.001). In conclusion, mVPS significantly extends the duration of EVD, which is particularly beneficial for patients requiring long-term EVD.

Stability Analysis and Construction Parameter Optimization of Tunnels in the Fractured Zone of Faults

In order to improve the construction method of highway tunnel fault, improve the excavation level, improve the construction efficiency, reduce the project cost, and shorten the construction period, so as to find a specific road, this paper puts forward the research method of tunnel stability analysis and construction parameter optimization in the fault fracture zone. First, this paper analyzes the specific geographical and geological environment of the construction site. Second, this paper compares and analyzes the effects of the drilling and blasting method and full-face tunnel boring machine (TBM) in construction and further analyzes the surrounding rock deformation, over excavation, and under excavation, as well as the range of loose circles when the surrounding rock is stable. Then, this paper discusses the minimum smooth blasting parameters under these conditions. Finally, the actual blasting effect of tunnel construction is tested and the optimization algorithm model of tunnel fault drilling and blasting parameters is established. The results show that the proposed optimization model of drilling and blasting construction parameters for highway tunnel faults based on the Support Vector Regression (SVR) algorithm combined with a genetic algorithm (GA) has a short calculation time and high parameter optimization accuracy. It is very feasible to optimize the construction parameters of the fault drilling and blasting method, which can greatly improve the construction efficiency, carry out the detailed simulation, reduce the cost, and increase safety. In summary, it has a certain reference significance for the optimization of highway tunnel construction and future research by drilling and blasting method under complex geological conditions in my country.

Zero-Calibrating External Ventricular Drains: Exploring Practice

ABSTRACT

BACKGROUND: Guidelines call for the removal of the nonvented cap (NVC) on the flushless transducer applied to the external ventricular drain (EVD) to zero the device to atmospheric pressure. Some hospitals have abandoned this practice to prevent opening the system to air. No data exist to determine the safest, most effective method of EVD zero-calibration. METHODS: A multidisciplinary team was assembled to use reflective practice to evaluate current zero-calibration of EVD practice. RESULTS: Clinical Nursing Focus showed recommendations largely out of date without detailed rationale or a high level of evidence. Manufacturer recommendations were fragmented and did not address rationale for technique. Bedside trial showed equivalence when comparing intracranial pressure (ICP) tidal, ICP after EVD zero with NVC removal, and ICP after EVD zero without NVC removal. CONCLUSION: Institutional guidelines were changed to reflect zero-calibration of EVD without NVC removal in systems that are amendable to this procedure. Further study is needed to determine best practice.