Application of the Preventable Shunt Revision Rate to an Adult Population

Does Valve Design Affect the Tensile Strength of Ventriculoperitoneal Shunts?

BACKGROUND AND OBJECTIVES

The most common treatment for hydrocephalus is ventriculoperitoneal (VP) shunting, which is problematic as shunts are prone to failure. Shunt disconnections account for a minority (8%-15%) of VP shunt failures but could be reduced through better shunt design. A better understanding of the mechanical properties of VP shunts would help explain why shunt disconnections occur. The objective of this study was to determine if the tensile properties of VP shunts differ by design.

METHODS

Linear tensile testing was conducted on 5 different valve designs (Codman Certas Plus Programmable Valve, Medtronic Delta, Integra Orbis Sigma Valve II, Medtronic PS Medical, Medtronic Strata Adjustable Valve) at both the proximal and distal ends to determine the maximum load which could be applied to different shunt designs. Each valve was progressively subjected to increasing force until the catheter disconnected from the valve, the catheter fractured, or our maximum testing limits were reached.

RESULTS

Catheters disconnected or fractured during testing with all valves. The maximum load resisted during tensile testing for similar locations in all valve designs were found to be statistically similar to one another. Only the PS Medical and Orbis Sigma II valves showed an increased maximum load at the distal end compared with the proximal end within the same device.

CONCLUSION

No single valve design was superior at preventing disconnections in VP shunts. Shunt disconnections remain a concerning problem as VP shunts are the gold standard for combating hydrocephalus.

Failure of Internal Cerebrospinal Fluid Shunt: A Systematic Review and Meta-Analysis of the Overall Prevalence in Adults

OBJECTIVE

Reported rates of failures of internal cerebrospinal fluid shunt (ICSFS) vary greatly from less than 5% to more than 50% and no meta-analysis to assess the overall prevalence has been performed. We estimated the failure rate after ICSFS insertion and searched for associated factors.

METHODS

Six databases were searched from January 1990 to February 2022. Only original articles reporting the rate of adult shunt failure were included. Random-effects meta-analysis with a generalized linear mixed model method and logit transformation was used to compute the overall failure prevalence. Subgroup analysis and meta-regression were implemented to search for associated factors.

RESULTS

Of 1763 identified articles, 46 were selected, comprising 70,859 ICSFS implantations and 13,603 shunt failures, suggesting an accumulated incidence of 19.2%. However, the calculated pooled prevalence value and its 95% confidence interval (CI) were 22.7% (95% CI, 19.8-5.8). The CI of the different estimates did not overlap, indicating a strong heterogeneity confirmed by a high I² of 97.5% (95% CI, 97.1-97.8; P < 0.001; τ² = 0.3). Ninety-five percent prediction interval of shunt failure prevalence ranged from 8.75% to 47.36%. A meta-regression of prevalence of publication found a barely significant decreasing failure rate of about 2% per year (-2.11; 95% CI, -4.02 to -0.2; P = 0.031).

CONCLUSIONS

Despite being a simple neurosurgical procedure, ICSFS insertion has one of the highest risk of complications, with failure prevalence involving more than 1 patient of 5. Nonetheless, all efforts to lower this high level of shunt failure seem to be effective.

COVID-19 and Ventricular Shunt Revisions

Introduction: COVID-19 patients frequently experience headaches, malaise, and fatigue. For patients with shunted hydrocephalus, these signs and symptoms can often be indicative of shunt failure. Thus, it can be challenging to determine if shunt failure has occurred in this patient population. Therefore, we explored the question of how a diagnosis of COVID-19 in shunted hydrocephalus patients influences the rate of shunt revision.

Methods: We used a deidentified database network (TriNetX) to gather information on patients with shunted hydrocephalus and COVID-19 versus no COVID-19 from January 20, 2020, through September 26, 2021. Our primary outcome of interest was shunt revision at 90 days, with secondary outcomes of mortality, hospitalization, ICU admission, mechanical ventilation, tracheostomy, PEG tube placement, fall, seizure, acute kidney injury (AKI), venous thromboembolism (VTE), ischemic stroke (I.S.), myocardial infarction (MI), and sepsis. Cohorts were propensity score-matched for common comorbidities and demographics.

Results: After propensity score matching, 10,600 patients with shunted hydrocephalus and COVID-19 (cohort 1) and 10,600 patients with shunted hydrocephalus and no COVID-19 (cohort 2) were identified. Average age was 38.5 years. Eight hundred and thirty-four patients (7.869%) in cohort 1 and 180 (1.698%) patients in cohort 2 underwent shunt revision (p=<0.0001, OR 4.978, 95% CI 4.198, 5.821). Mortality was 4.642% vs. 2.113% (p<0.0001, OR 2.255, 95% CI 1.921, 2.647). Hospitalization rates were 27.72% vs. 10.303% (p<0.0001), and ICU admission rates 11.567% vs. 3.463% (p<0.0001). Ventilator dependence was 3.529% vs. 0.953% (p<0.0001), tracheostomy 1.142% vs. 0.236% (p<0.0001), PEG tube insertion 2.472% vs. 0.585% (p<0.0001), falls 2.321% vs. 1.076% (p<0.0001), seizure 11.369% vs. 5.953% (p<0.0001), AKI 4.416% vs. 1.717% (p<0.0001), VTE 3.538% vs. 1.293% (p<0.0001), sepsis 3.887% vs. 1.179% (p<0.0001), IS 0.585% vs. 0.16% (p<0.0001), and MI 1.34% vs. 0.519% (p<0.0001).

Conclusion: COVID-19 infection is associated with an almost five-fold increase in shunt revisions.

Hydrocephalus Study Design: Testing New Hypotheses in Clinical Studies and Bench-to-Bedside Research

In this article, we aimed to describe some of the currently most challenging problems in neurosurgical management of hydrocephalus and how these can be reasons for inspiration for and development of research. We chose 4 areas of focus: 2 dedicated to improvement of current treatments (shunt implant surgery and endoscopic hydrocephalus surgery) and 2 dedicated to emerging future treatment principles (molecular mechanisms of cerebrospinal fluid secretion and hydrocephalus genetics).

Analysis of neurosurgical procedures with unplanned reoperation for quality improvement: A 5-year single hospital study

The unplanned return to the operating room rate is a quality metric for assessing hospital performance. This study aimed to evaluate the cause, incidence, and time interval of unplanned returns in index neurosurgical procedures within 30 days of the initial surgery as an internal audit. We retrospectively analyzed neurosurgical procedures between January 2015, and December 2019, in a single regional hospital. The definition of an unplanned return to the operating room was a patient who underwent two operations within 30 days when the second procedure was not planned, staged, or related to the natural course of the disease.A total of 4365 patients were identified in our analysis, of which 93 (2%) had an unplanned return to the operating room within 30 days of their initial surgery during admission. The most common reason for an unplanned return to the operating room for a cranial procedure was hemorrhage, followed by hydrocephalus and subdural effusion, which accounted for 49.5%(46/93), 12%(11/93), and 5.4%(5/93) of cases, respectively. In spinal procedures, the most common cause of return was a residual disc, followed by surgical site infection, which accounted for 5.4%(5/93) and 4.3%(4/93) of cases, respectively. The overall median time interval for unplanned returns to the operating room was 3 days (interquartile range, 1-9).Lowering the rate of postoperative hemorrhage in cranial surgery and postoperative residual disc in spine surgery was crucial as an internal audit in a 5-year single institute follow-up. However, the unplanned reoperation rate is less helpful in benchmarking because of the heterogeneity of patients between hospitals.

Mechanical complications of cerebrospinal fluid shunt. Differences between adult and pediatric populations: myths or reality?

OBJECTIVE

Shunt malfunctions seem more frequent in children (44 to 81%) than in adults (18 to 29%). Because of discrepancies between studies, it is not possible to affirm this disparity. The objective was to verify whether the incidence of cerebrospinal fluid (CSF) shunt malfunctions is higher in children than adults.

METHODS

We present a retrospective series of child and adult patients who underwent CSF shunt placement between 2000 and 2013 with a Sophysa SM8® valve.

RESULTS

599 adults and 98 children (sex ratio 1.28) underwent CSF shunt placement. Age at first surgery ranged between 1 day of life and 90 years (mean of 55.8 years, SD 25.8, median 64.8 years). The mean follow-up was 4 years (SD 4.264, 0-16; median 3 years). The cumulative complication rate was 25.5% (178/697). Mechanical complications were disconnection (25.1%), migration (11.8%), intracranial catheter obstruction (8.9%) and malposition (8.4%). The mean delay for the first revision was 1.90 years (0-13.9), (SD 2.73, median 0.5). The probability of shunt failure was 65% at 10 years in the child group and 36% at 10 years in the adult group. Moreover, in the child group, 33% of revisions occurred during the first year after shunt placement versus 17% in the adult group. Thus, the probability of shunt failure was higher in children than in adults (log-rank test, p < 0.001).

CONCLUSIONS

This is the first retrospective study, comparing children and adults undergoing CSF shunt using the same valve, able to confirm the higher rate of complications in children.