Reposted with permission from ©AANS, 2014
J Neurosurg Pediatrics (Suppl) 14:24–29, 2014
AANS, 2014
(Original text of the guideline was edited to reflect the update.  Please click here for the original publication.)

Pediatric hydrocephalus: systematic literature review and evidence-based guidelines

Part 3: Endoscopic computer-assisted electromagnetic navigation and ultrasonography as technical adjuvants for shunt placement

UPDATE

Ann Marie Flannery, MD,¹ Ann-Christine Duhaime, MD,²  Mandeep S. Tamber, MD, PhD,³ Joanna Kemp, MD¹

¹Department of Neurological Surgery, Saint Louis University, St. Louis, Missouri; ²Department of Pediatric Neurosurgery, Massachusetts General Hospital, Boston, Massachusetts; and ³Department of Pediatric Neurological Surgery, Children’s Hospital of Pittsburgh, University of Pittsburgh, Pittsburgh, Pennsylvania

Object. This systematic review was undertaken to answer the following question: Do technical adjuvants such as ventricular endoscopic placement, computer-assisted electromagnetic guidance, or ultrasound guidance improve ventricular shunt function and survival?

Methods. The US National Library of Medicine PubMed/MEDLINE database and the Cochrane Database of Systematic Reviews were queried using MeSH headings and key words specifically chosen to identify published articles detailing the use of cerebrospinal fluid shunts for the treatment of pediatric hydrocephalus. Articles meeting specific criteria that had been delineated a priori were then examined, and data were abstracted and compiled in evidentiary tables. These data were then analyzed by the Pediatric Hydrocephalus Systematic Review and EvidenceBased Guidelines Task Force to consider evidence-based treatment recommendations.

Results. The search yielded 163 abstracts, which were screened for potential relevance to the application of technical adjuvants in shunt placement. Fourteen articles were selected for full-text review. One additional article was selected during a review of literature citations. Eight of these articles were included in the final recommendations concerning the use of endoscopy, ultrasonography, and electromagnetic image guidance during shunt placement, whereas the remaining articles were excluded due to poor evidence or lack of relevance.

The evidence included 1 Class I, 1 Class II, and 6 Class III papers. An evidentiary table of relevant articles was created.

Conclusions. Recommendation: There is insufficient evidence to recommend the use of endoscopic guidance for routine ventricular catheter placement. Strength of Recommendation: Level I, high degree of clinical certainty.

Recommendation: The routine use of ultrasound-assisted catheter placement is an option. Strength of Recommendation: Level III, unclear clinical certainty.

Recommendation: The routine use of computer-assisted electromagnetic (EM) navigation is an option. Strength of Recommendation: Level III, unclear clinical certainty.

(http://thejns.org/doi/abs/10.3171/2014.7.PEDS14323)

Key Words: cerebrospinal fluid shunt, hydrocephalus, ultrasonography, ventricular catheter, ventricular shunt, computer-assisted navigation, image-guided navigation, electromagnetic guidance, endoscopy, practice guidelines

Abbreviations used in this paper: AANS = American Association of Neurological Surgeons; CNS = Congress of Neurological Surgeons; EM = electromagnetic ; ETV = endoscopic third ventriculostomy.

As navigation, imaging, and endoscopy have increasingly been used in the field of neurosurgery, they have been applied to the placement of CSF shunts. Surgeons have used these technical adjuvants in attempts to accomplish good catheter placement with the hopes of improving the longevity of the shunt as well as reducing potential complications. This specific systematic review was undertaken to answer the following question: Do technical adjuvants such as ventricular endoscopic placement, computer-assisted elect romagnetic (EM) guidance, or ultrasound guidance improve ventricular shunt function and survival? As seen in the following Methods section, we conducted a search for articles on the use of CSF shunts in pediatric patients with hydrocephalus. The original search yielded 163 abstracts, which were screened for their potential relevance to the application of technical adjuvants in shunt placement. Fifteen articles were deemed relevant. Eight of these articles were included in the final recommendations for the use of endoscopy, ultrasonography, or EM image guidance in the placement of shunts, with the remainder excluded due to poor evidence or lack of relevance.

Authors performed an update of the original search yielding 118 citations, of which 8 were selected for full text review.  Four studies were included, confirming the original recommendations.  The remainder were excluded.

Methods

The US National Library of Medicine PubMed/ MED LINE database and the Cochrane Database of Systematic Reviews were queried for the period January 1966 through March 2012 using MeSH headings and key words specifically chosen to identify published articles detailing the use of CSF shunts for the treatment of pediatric hydrocephalus. Please see below for the specific search terms and strategies used (Fig. 1).

Authors performed an updated literature search (in PubMed and Cochrane Central) for this guideline chapter through a medical librarian at the Congress of Neurological Surgeons Guidelines office using the below-mentioned existing search terms to update the original search through November 30, 2019 (Figure 2).

Search Terms

PubMed/MEDLINE

1. (“Cerebrospinal Fluid Shunts”[MeSH]) AND “Hydrocephalus”[MeSH:noexp]
2. Limit 1 to Child (0–18 years)
3. 2 and ((ventricular AND (catheter OR shunt)) AND (“computer assisted” OR “image guided” OR electromagnetic OR ultrasound OR Endoscopy[MeSH] OR endoscop*))
4. Limit to English and Humans

Cochrane Database

1. MeSH descriptor Child
2. MeSH descriptor Infant
3. 1 or 2 and (MeSH descriptor Cerebrospinal Fluid

Shunts)

4. 3 and (MeSH descriptor Hydrocephalus)
5. 4 and (ventricular NEAR/2 (catheter OR shunt))
6. (computer OR ultrasound OR endoscop*)
7. 5 and 6

Search Strategies

Articles meeting specific criteria that had been delineated a priori were then examined, and the data yielded were abstracted and compiled in evidentiary tables (Tables 1–4). These data were then analyzed by the Pediatric Hydrocephalus Systematic Review and Evidence-Based Guidelines Task Force to consider evidence-based treatment recommendations.

Fig. 1. Flowchart showing the process involved in identifying relevant literature.

Fig. 2.  Flowchart showing the process involved in identifying relevant literature for the 2020 Update. The criteria for “records excluded” and “full text articles excluded with reasons” are detailed in Part 1 of the Guidelines.

Results

Endoscopy

Recommendation: There is insufficient evidence to recommend using endoscopic guidance for routine ventricular catheter placement. Strength of Recommendation: Level I, high degree of clinical certainty.

Four studies were identified to assess the use of endoscopy in the placement of ventricular catheters (Table 1). Two of the earlier reports in the literature described a case series by Vries¹ and another by Kellnar et al.² Vries¹ described the technique for insertion of endoscopically placed catheters and reported that 79% of patients for whom endoscopy was used did not require further shunt revision. However, the author did not report the follow-up period, and without a control arm there is no clear demonstration of an advantage of using the endoscope over the standard technique, which relies on anatomical landmarks. Kellnar et al.² described a case series in which neuroendoscopy was used for placement of ventricular catheters in 14 patients. These authors demonstrated the feasibility of their technique and stated that there were no revisions due to catheter malposition during an 18-month followup period.² Again, without a control group, no conclusions can be drawn regarding an advantage of endoscopic shunt insertion over standard techniques.

A later study by Villavicencio et al³ retrospectively compared the survival of shunts placed with neuroendoscopic guidance to that of shunts placed without guidance. The authors found no advantage to overall shunt survival between the two study groups (hazard ratio 1.08, 95% CI 0.84–1.41). They did, however, note that the risk of proximal failure was lower in the endoscopy group (odds ratio 0.56, 95% CI 0.32–0.93) and observed an increased rate of distal malfunction when compared with shunts placed without endoscopic assistance.

The strongest evidence that the routine use of endoscopic placement did not improve outcome was reported by Kestle and colleagues⁴ in a randomized controlled trial in which 393 patients requiring a shunt were randomized into either an endoscopy group or a standard group. There were no significant differences in the overall shunt survival rate between the groups (p = 0.09) or in the postoperative assessment of optimal catheter placement (away from the choroid plexus). The most common cause of shunt failure was proximal obstruction in both groups.

TABLE 1: Use of endoscopy in the placement of ventricular catheters: summary of evidence*

TABLE 2: Use of ultrasound guidance in the placement of ventricular catheters: summary of evidence

TABLE 3: Use of electromagnetic image guidance in the placement of ventricular catheters: summary of evidence

Ultrasound Guidance

Recommendation: The routine use of ultrasound-assisted catheter placement is an option. Strength of Recommendation: Level III, unclear clinical certainty.

The supporting evidence consisted of 1 Class III study with limited follow-up and no control or comparison (Table 2).

Few studies have sought to evaluate the utility of ultrasound in the placement of ventricular catheters. One Class III cohort study with a limited follow-up and no control or comparison met the inclusion criteria and was included as evidence to support this topic. Whitehead et al⁵ described the technique of placing the ventricular catheter with ultrasound guidance in pediatric patients with closed fontanelles. The authors described the creation of a 2-cm bur hole, followed by catheter placement and ultrasonography to confirm catheter location. There was no analysis of outcomes related to shunt longevity, but immediate postoperative imaging did confirm the expected placement of the catheter away from the choroid plexus.⁵ Ultrasound-assisted catheter placement may be used to confirm placement of the proximal catheter within the cerebral ventricle.

Electromagnetic Image Guidance

Recommendation: The routine use of computer assisted electromagnetic (EM) navigation is an option. Strength of Recommendation: Level III, unclear clinical certainty.

One Class II study, which did not reach significance in the pediatric subset, and 1 Class III study, which reported a decrease in proximal failure compared with historical reports, were included as evidence to support this topic.

Electromagnetic image guidance has been used (and studied in the pediatric hydrocephalus literature) as a technical adjuvant for assisting placement of ventricular catheters. In a case series by Clark et al⁶ published in 2008, prospectively collected data confirmed the feasibility of using EM image guidance, specifically in 23 patients with anatomy that was difficult to navigate, including those with small and slit ventricles or complex loculated hydrocephalus. These authors demonstrated a 9% proximal revision rate in the 7-month follow-up period, which they compared with a historical control group in which there was a 35% failure rate. The authors proposed a randomized controlled trial to strengthen this evidence, as their study did not have its own control, had a short follow-up period, and included a small number of patients.

An article by Hayhurst and coauthors⁷ described a nonrandomized prospective cohort study in which standard shunt placement was compared with EM image– guided shunt placement in both adult and pediatric patients. The end points of the study were failure rates as well as grading of the catheter position as follows: Grade 1, catheter tip floating in CSF equidistant from the ventricle walls, away from the choroid plexus, and in a straight trajectory from the bur hole; Grade 2, catheter tip touching the ventricle wall or the choroid plexus; and Grade 3, part of the catheter tip within the parenchyma or failure to cannulate the ventricle completely. The pediatric cases were analyzed separately with regard to shunt failure, and the data showed a 30% failure rate in the standard cohort and a 20% failure rate in the EM image guidance cohort. This difference was statistically insignificant. In the entire cohort, which included both adult and pediatric patients, “the rate of proximal obstruction falls ... from 17 to 6% [when] using EM-navigated placement (p = 0.129, Fisher exact test).”⁷ Despite that, the overall failure rate was still equivalent, as other components of the system failed, even when the proximal catheter performance improved. There were no Grade 3 catheter positions in the EM image guidance group; this did have a significant impact on shunt survival compared with Grades 1 and 2. These data were not analyzed independently for the pediatric patients included in the study.⁷

A recent paper by Levitt et al⁸ also looked at the use of EM navigation versus standard shunt placement. The authors retrospectively analyzed 102 surgeries with frontal catheter placement in pediatric patients to identify the rates of subsequent shunt failure and catheter positioning with the same grading as previously described. The authors found no significant difference in the incidence of proximal obstruction in the EM guidance group (25%) compared with the standard technique group (22%). There was significantly improved catheter positioning in the EM guidance group, although this had no impact on shunt survival. Patients in the EM guidance group were more likely to have small or difficult-to-navigate ventricular anatomy.

Excluded Articles

Seven articles were identified, reviewed, and ultimately excluded because of weak evidence, incomplete evidence, or irrelevance regarding the application of technical adjuvants.^9-15 Lam and colleagues¹² discussed a Seldinger technique for placing ventricular catheters over endoscopes, and included only a single case. A paper by Chernov et al¹⁶ was excluded for a number of factors, including the fact that there were only 4 patients in one group (endoscopic third ventriculostomy [ETV]) and the inclusion range of 5–21 years included 5 patients who were 20 years of age or older.⁹ In a retrospective review, Shim and colleagues¹⁵ compared infants treated with ETV and shunts with infants treated with shunts alone. The authors found improved longevity of the shunt when combined with ETV. Gil et al¹¹ retrospectively evaluated ventricular catheter placement with a frameless optical navigation system, but their study included only 9 patients and was excluded for having a sample size smaller than 10. McMillen et al¹³ used EM image guidance for a variety of conditions in children that included only 3 cases of hydrocephalus. Piatt and Garton’s paper¹⁴ was excluded because it was an analysis of shunt failure and related infection symptoms and frequencies using data derived from two large multicenter studies without direct reference to the techniques being considered in this review. Finally, Farahmand and colleagues¹⁰ presented information on a large group of patients older than 16 years of age without separately reporting individuals between the ages of 16 and 19 years, who could have been included.

2020 Update

This review yielded 118 abstracts, of which 8 were selected for full text review. Seven studies were excluded after review^8,17-22.  There were 4 studies^17,18, relevant to ultrasound, but only Whitehead et al²³ met inclusion criteria.  This study is based on class II data indicating that ultrasound assisted shunt catheter placement did not result in a statistically significant improvement in shunt survival.  Studies relevant to endoscopy¹⁹ and image guidance^20,21 did not meet criteria for inclusion. In conclusion, Whitehead et al²³ confirmed the recommendation from the original guideline that ultrasound is an option.

Conclusions

Endoscopy

Recommendation: There is insufficient evidence to recommend using endoscopic guidance for routine ventricular catheter placement. Strength of Recommendation: Level I, high degree of clinical certainty.

Ultrasound Guidance

Recommendation: The routine use of ultrasound-assisted catheter placement is an option. Strength of Recommendation: Level III, unclear clinical certainty.

Electromagnetic Image Guidance

Recommendation: The routine use of computer assisted electromagnetic (EM) navigation is an option. Strength of Recommendation: Level III, unclear clinical certainty.

The availability and quality of evidence is variable throughout the literature for the application of technical adjuvants for catheter placement in the treatment of hydrocephalus by CSF shunting. The strongest body of evidence applies to the use of endoscopy in insertion of shunts. Based on this evidence, endoscopy cannot be recommended for routine use, as no benefit of its application could be identified in the available literature. Less evidence exists for ultrasound and EM image guidance, and therefore a conclusive recommendation cannot be made. Catheter position may be optimized with the application of these technologies, although they may not have an impact on overall outcome with regard to shunt longevity. Insufficient data exist for the use of technical adjuncts in patients with more challenging anatomy, or in the situation in which the ventricle is unable to be cannulated using standard anatomical techniques.

Acknowledgments

We acknowledge the American Association of Neurological Surgeons (AANS)/Congress of Neurological Surgeons (CNS) Joint Guidelines Committee for the members’ reviews, comments, and suggestions; Laura Mitchell, Guidelines Project Manager for the CNS, for her contributions; Pamela Shaw, research librarian, for her assistance with the literature searches; Kevin Boyer for his assistance with data analysis; and Sue Ann Kawecki for her assistance with editing. We also acknowledge the following peer reviewers for their contributions to review the update to the guidelines: Jennifer Sweet, MD, Brandon Rocque, MD, Christoph Greissenauer, MD, Jeffrey Olson, MD.

Disclosure

The systematic review and evidence-based guidelines were funded exclusively by the CNS and AANS Pediatric Section, which received no funding from outside commercial sources to support the development of this document.

Conflict(s) of Interest: None. All Task Force members declared any potential conflicts of interest prior to beginning work on this evidence review.

Conflict(s) of Interest: None. All Pediatric Hydrocephalus Systematic Review and Evidence-Based Guidelines Update Task Force members declared any potential conflicts of interest prior to beginning work on this systematic review and evidence-based guidelines.

Author contributions to the study and manuscript preparation include the following. Conception and design: AANS/CNS Joint Section on Pediatrics. Acquisition of data: all authors. Analysis and interpretation of data: all authors. Drafting the article: Flannery. Critically revising the article: all authors. Reviewed submitted version of manuscript: all authors. Approved the final version of the manuscript on behalf of all authors: Flannery. Administrative/technical/material support: all authors. Study supervision: Flannery.

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