Risk factors for hydrocephalus following fourth ventricle tumor surgery: A retrospective analysis of 121 patients

Tengyun Chen; Yanming Ren; Chenghong Wang; Bowen Huang; Zhigang Lan; Wenke Liu; Yan Ju; Xuhui Hui; Yuekang Zhang

doi:10.1371/journal.pone.0241853

Peer Review History

Original SubmissionAugust 1, 2020
7 Sep 2020 Decision Letter - Michael C Burger, Editor PONE-D-20-23644 Risk factors for hydrocephalus following fourth ventricle tumor surgery: A retrospective analysis of 121 patients PLOS ONE Dear Dr. Zhang, Thank you for submitting your manuscript to PLOS ONE. After careful consideration, we feel that it has merit but does not fully meet PLOS ONE’s publication criteria as it currently stands. Therefore, we invite you to submit a revised version of the manuscript that addresses the points raised during the review process. The reviewers did have rather divergent opinions on the manuscript. Please adress the issues brought forward by the reviewers, and change the manuscript where reasonable. Where this is not possible, please explain your standpoint. Please submit your revised manuscript by Oct 22 2020 11:59PM. If you will need more time than this to complete your revisions, please reply to this message or contact the journal office at plosone@plos.org. When you're ready to submit your revision, log on to https://www.editorialmanager.com/pone/ and select the 'Submissions Needing Revision' folder to locate your manuscript file. Please include the following items when submitting your revised manuscript: A rebuttal letter that responds to each point raised by the academic editor and reviewer(s). You should upload this letter as a separate file labeled 'Response to Reviewers'. A marked-up copy of your manuscript that highlights changes made to the original version. You should upload this as a separate file labeled 'Revised Manuscript with Track Changes'. An unmarked version of your revised paper without tracked changes. You should upload this as a separate file labeled 'Manuscript'. If you would like to make changes to your financial disclosure, please include your updated statement in your cover letter. Guidelines for resubmitting your figure files are available below the reviewer comments at the end of this letter. If applicable, we recommend that you deposit your laboratory protocols in protocols.io to enhance the reproducibility of your results. Protocols.io assigns your protocol its own identifier (DOI) so that it can be cited independently in the future. For instructions see: http://journals.plos.org/plosone/s/submission-guidelines#loc-laboratory-protocols We look forward to receiving your revised manuscript. Kind regards, Michael C Burger, M.D. Academic Editor PLOS ONE Journal Requirements: When submitting your revision, we need you to address these additional requirements. 1. Please ensure that your manuscript meets PLOS ONE's style requirements, including those for file naming. The PLOS ONE style templates can be found at https://journals.plos.org/plosone/s/file?id=wjVg/PLOSOne_formatting_sample_main_body.pdf and https://journals.plos.org/plosone/s/file?id=ba62/PLOSOne_formatting_sample_title_authors_affiliations.pdf 2. Thank you for stating the following financial disclosure: "The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript." At this time, please address the following queries: Please clarify the sources of funding (financial or material support) for your study. List the grants or organizations that supported your study, including funding received from your institution. State what role the funders took in the study. If the funders had no role in your study, please state: “The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.” If any authors received a salary from any of your funders, please state which authors and which funders. If you did not receive any funding for this study, please state: “The authors received no specific funding for this work.” Please include your amended statements within your cover letter; we will change the online submission form on your behalf. 3. Please include captions for your Supporting Information files at the end of your manuscript, and update any in-text citations to match accordingly. Please see our Supporting Information guidelines for more information: http://journals.plos.org/plosone/s/supporting-information. [Note: HTML markup is below. Please do not edit.] Reviewers' comments: Reviewer's Responses to Questions Comments to the Author 1. Is the manuscript technically sound, and do the data support the conclusions? The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented. Reviewer #1: Yes Reviewer #2: Partly Reviewer #3: Yes Reviewer #4: Yes Reviewer #5: No Reviewer #6: Yes Reviewer #7: Yes ******** 2. Has the statistical analysis been performed appropriately and rigorously? Reviewer #1: Yes Reviewer #2: Yes Reviewer #3: Yes Reviewer #4: Yes Reviewer #5: I Don't Know Reviewer #6: Yes Reviewer #7: Yes ****** 3. Have the authors made all data underlying the findings in their manuscript fully available? The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified. Reviewer #1: No Reviewer #2: Yes Reviewer #3: Yes Reviewer #4: Yes Reviewer #5: Yes Reviewer #6: Yes Reviewer #7: Yes ****** 4. Is the manuscript presented in an intelligible fashion and written in standard English? PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here. Reviewer #1: Yes Reviewer #2: Yes Reviewer #3: Yes Reviewer #4: Yes Reviewer #5: Yes Reviewer #6: Yes Reviewer #7: Yes ****** 5. Review Comments to the Author Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters) Reviewer #1: This study is a retrospective chart review that addresses the incidence of persistent postoperative hydrocephalus requiring surgery, in patients undergoing surgery for resection of fourth ventricular tumors. The study adds significantly to existing knowledge about this issue. The study includes a large number of patients, who were treated using a relatively standardized protocol. The analysis was thoughtfully designed and uses statistics appropriately. I believe that this study will be useful for practicing neurosurgeons, in order tocounsel patients and their families appropriately about the likelihood of needing additional surgeries (ETV or shunt) to treat hydrocephalus, after resection of 4th ventricular tumors, and in order to assess the likelihood of EVD weaning after these surgeries. Reviewer #2: PONE-D-20-23644 Title: Risk factors for hydrocephalus following fourth ventricle tumor surgery: A retrospective analysis of 121 patients Aim: Identify risk factors for postoperative hydrocephalus and the need for a postoperative CSF diversion. Retrospective study of 121 patients with fourth ventricle tumor treated with tumor resection (histologically verified single intracranial lesion). Main outcome variable – post resection CSF diversion (EVD or VP-shunt) Main results: 121 patients. Median age was 24 years (IQR, 9-41 years). The most common tumors were ependymoma (30.6%), followed by medulloblastoma (24.2%) and pilocytic astrocytoma (16.5%). 56/121 patients had prophylactic EVD placement. Fifteen patients underwent postoperative CSF diversion, which included 10 VP shunts and 5 EVDs. Of the 10 VP shunts, 9 cases had a prophylactic EVD placement, and only one underwent postoperative EVD before VP shunt placement. Multivariate analysis identified superior extension and subtotal resection as independent risk factors for post resection CSF drainage (EVD or VP-shunt). Comments: 1. The manuscript is well written and easy to read. 2. The topic is relevant and of general interest. 3. My main objection to this manuscript is the choice of main outcome variable. In my opinion, the combination of post-resection EVD and permanent VP is confusing, all the time 56/121 had placement of EVD before resection. I would have preferred to use permanent VP alone as main outcome variable. Doing this, pre-operative HC will most likely remain significantly associated with post-resection VP placement. I encourage the authors to at least include such an analysis. It is of course interesting to note that 5/65 patients without pre-resection placement of EVD needed EVD in the early postoperative period, but only on of these five ended up with VP. 4. Identifying superior extension and subtotal resection as independent risk factors for post resection CSF drainage (EVD or VP-shunt) is absolutely of clinical interest, but will be even more interesting if analyzed according to the comment above. 5. Pre-resection endoscopic third ventriculostomy (ETV) is an alternative to EVD, and may reduce the need for permanent VP. The mention of ETV in the discussion is somewhat brief. Reviewer #3: The authors have sufficiently addressed my concerns and feel that with the changes the article is not suitable for publication. The authors have significantly enhanced the discussion section that was previously lacking. Reviewer #4: This is a nice series which outlines the 4th ventricular tumor situations which are more likely to lead to persistent hydrocephalus requiring shunting. The authors are to be congratulated on this analysis. Reviewer #5: This is a large series but the results are not surprising. The conclusions are simple yet well known to the reader. Several comments that deserve further discussion are 1. what were indications for preoperative EVD placement and timing for such procedure in relation to tumor surgery. 2. What was the timing for definitive CSF diversion surgery in relation to the index tumor operation 3. What was incidence of complications with the shunt procedure 4. What was the shunt infection rate? 5. Did the authors consider an ETV rather than VP shunt Reviewer #6: Manuscript review: Risk factors for hydrocephalus following fourth metrical tumor surgery: a retrospective analysis of 121 patients. (PONE-D-20-23644) The authors of this retrospective review describe their experience from 2013-2018 with 121 patients who presented with fourth ventricular tumors and had a first time resection surgery for the lesion. Patients had a median age of 24 years and all had six months follow up after initial surgery. The objective of the study was to identify factors that predispose such patients to develop hydrocephalus and needing (ventriculo-peritoneal shunt) VPS for CSF diversion. Of the total 121 patients enrolled 16 patients eventually underwent permanent VPS placement. The univariate analysis demonstrated that superior extension into the aqueduct, preoperative hydrocephalus, and subtotal resection of the mass were significantly associated with postoperative hydrocephalus. This retrospective analysis is well written and a significant univariate and multivariate statistical analysis was completed in an attempt to identify specific factors associated with this patient population but a few questions arise. The median age of the patient population is 24 years of age and this should be more explicitly mentioned, perhaps even in the title of the manuscript, as typically fourth ventricular tumors tend to be more highly concentrated in a pediatric population. The conclusions from the paper state that superior tumor extension and failed gross total resection were independent risk factors for VPS placement. However this makes one wonder whether a subtotal resection within the aqueduct led to hydrocephalus. If this is the case then this is an obvious conclusion in that the obstruction through the ventricular system was not alleviated. However, if indeed, superior extension and failed total resection were not factors related to the same patients then this needs to be further explained in the manuscript and the manuscript would benefit from the authors’ hypotheses on how this would then lead to hydrocephalus. In addition to having a data analysis on initial extension of the tumor on patient presentation, a further explanation of which areas of tumor were left behind when a gross total resection was not possible would also assist in explaining the results. Further, the authors mentioned that endoscopic third ventriculostomy (ETV) was a consideration for patients with fourth ventricular obstruction. The paper does not address why none of the patients who eventually underwent VPS placement were or were not considered for ETV as this may have been able to avoid permanent CSF diversion through a shunt. In conclusion the manuscript nicely evaluates many different factors associated with this patient population however the manuscript in its current state seems to address the conclusions in a rather simplistic fashion and as such the conclusions do not seem to add much new knowledge in the field. Reviewer #7: The authors present a series of 121 patient's with posterior fossa tumors to try to determine prognostic indicators for the development of postoperative hydrocephalus that requires CSF diversion. There is a basic assumption in this manuscript which may be falacious: Regardless of pathology it is the anatomic extent of the tumor that determines hydrocephalus. Although using appropriate statistical analysis the office did not demonstrate significance of pathology, the subgroup's may be too small to provide a true "real world answer". My 2nd concern is that this is predominantly an article of teenagers and young adults. In the discussion the role of age and its implication for development of hydrocephalus is briefly reviewed but I believe this needs to be further expanded. It is not just age but the more aggressive nature of the tumors that we see in children under 5 years of age and particularly under 3 years of age with leptomeningeal dissemination that may increase the risk of hydrocephalus. The older patients in this study and the relatively small number of those with medulloblastoma may give a false impression of watch factors truly influence the development of hydrocephalus. The statistically significant finding of superior extent of the tumor increasing the risk for postoperative hydrocephalus is novel and of interest. I would be curious if this finding would hold up if the authors limited the population studied 2 patients over 16 years of age, that is those that are anatomically adult. I am not certain that this finding would be seen in younger children, particular with medulloblastoma where the mean age is below that of the study population in this manuscript. ****** 6. PLOS authors have the option to publish the peer review history of their article (what does this mean?). If published, this will include your full peer review and any attached files. If you choose “no”, your identity will remain anonymous but your review may still be made public. Do you want your identity to be public for this peer review? For information about this choice, including consent withdrawal, please see our Privacy Policy. Reviewer #1: Yes: Ronald Benveniste Reviewer #2: Yes: Eirik Helseth Reviewer #3: No Reviewer #4: Yes:** Lawrence M Shuer Reviewer #5: No Reviewer #6: No Reviewer #7: No [NOTE: If reviewer comments were submitted as an attachment file, they will be attached to this email and accessible via the submission site. Please log into your account, locate the manuscript record, and check for the action link "View Attachments". If this link does not appear, there are no attachment files.] While revising your submission, please upload your figure files to the Preflight Analysis and Conversion Engine (PACE) digital diagnostic tool, https://pacev2.apexcovantage.com/. PACE helps ensure that figures meet PLOS requirements. To use PACE, you must first register as a user. Registration is free. Then, login and navigate to the UPLOAD tab, where you will find detailed instructions on how to use the tool. If you encounter any issues or have any questions when using PACE, please email PLOS at figures@plos.org. Please note that Supporting Information files do not need this step. https://doi.org/10.1371/journal.pone.0241853.r001
Revision 1
24 Sep 2020 Author Response Dear Editors: Thank you for your letter and comments concerning our manuscript entitled "Risk factors for hydrocephalus following fourth ventricle tumor surgery: A retrospective analysis of 121 patients" (PONE-D-20-23644). We have studied the comments carefully and made corresponding modifications. All modifications in the manuscript were highlighted in red. The main corrections in the paper and the responses to the reviewers’ and editor’s comments are as follows:________________________________________ Reviewers’ comments: Reviewer #1 1. This study is a retrospective chart review that addresses the incidence of persistent postoperative hydrocephalus requiring surgery, in patients undergoing surgery for resection of fourth ventricular tumors. The study adds significantly to existing knowledge about this issue. The study includes a large number of patients, who were treated using a relatively standardized protocol. The analysis was thoughtfully designed and uses statistics appropriately. I believe that this study will be useful for practicing neurosurgeons, in order to counsel patients and their families appropriately about the likelihood of needing additional surgeries (ETV or shunt) to treat hydrocephalus, after resection of 4th ventricular tumors, and in order to assess the likelihood of EVD weaning after these surgeries. Authors’ response: Thank you for the comments. Reviewer #2 1. The manuscript is well written and easy to read. Authors’ response: Thank you for the comment. 2. The topic is relevant and of general interest. Authors’ response: Thank you for the comment. 3. My main objection to this manuscript is the choice of main outcome variable. In my opinion, the combination of post-resection EVD and permanent VP is confusing, all the time 56/121 had placement of EVD before resection. I would have preferred to use permanent VP alone as main outcome variable. Doing this, pre-operative HC will most likely remain significantly associated with post-resection VP placement. I encourage the authors to at least include such an analysis. It is of course interesting to note that 5/65 patients without pre-resection placement of EVD needed EVD in the early postoperative period, but only one of these five ended up with VP. Authors’ response: We have added this analysis. (Page8, line172-179) 4. Identifying superior extension and subtotal resection as independent risk factors for post resection CSF drainage (EVD or VP-shunt) is absolutely of clinical interest, but will be even more interesting if analyzed according to the comment above. Authors’ response: It has been analyzed according to the comment above. 5. Pre-resection endoscopic third ventriculostomy (ETV) is an alternative to EVD, and may reduce the need for permanent VP. The mention of ETV in the discussion is somewhat brief. Authors’ response: We have added some details about EVT in the discussion. (Page13, line 264-274) Reviewer #3 1. The authors have sufficiently addressed my concerns and feel that with the changes the article is not suitable for publication. The authors have significantly enhanced the discussion section that was previously lacking. Authors’ response: Thank you for your comment. But we did not make a revision before. Reviewer #4 1. This is a nice series which outlines the 4th ventricular tumor situations which are more likely to lead to persistent hydrocephalus requiring shunting. The authors are to be congratulated on this analysis. Authors’ response: Thank you for the comment. Reviewer #5 1. what were indications for preoperative EVD placement and timing for such procedure in relation to tumor surgery Authors’ response: We have described the indications in the sentence (Page5, line 114-116). And we have added details about the timing for preoperative EVD placement (Page5, line 116-118). 2. What was the timing for definitive CSF diversion surgery in relation to the index tumor operation Authors’ response: We have described them in the sentence (Page 5, line 126-128). 3. What was incidence of complications with the shunt procedure Authors’ response: No serious complications occurred in any of the cases of VP shunting during the follow-up period. 4. What was the shunt infection rate? Authors’ response: No patient with shunt infection was found during the follow-up period. 5. Did the authors consider an ETV rather than VP shunt Authors’ response: Thank you for your valuable comment. We did not routinely perform ETV when the patients in this study were treated for hydrocephalus. But now, ETV was performed more than VP in our hospital. Moreover, the type of surgery for postoperative hydrocephalus do not affect the occurrence of postoperative hydrocephalus as well as the risk factors. Reviewer #6 1. The median age of the patient population is 24 years of age and this should be more explicitly mentioned, perhaps even in the title of the manuscript, as typically fourth ventricular tumors tend to be more highly concentrated in a pediatric population. Authors’ response: We have explicitly mentioned and added details about age in the outcome. (Table 1) 2. The conclusions from the paper state that superior tumor extension and failed gross total resection were independent risk factors for VPS placement. However, this makes one wonder whether a subtotal resection within the aqueduct led to hydrocephalus. If this is the case then this is an obvious conclusion in that the obstruction through the ventricular system was not alleviated. However, if indeed, superior extension and failed total resection were not factors related to the same patients then this needs to be further explained in the manuscript and the manuscript would benefit from the authors’ hypotheses on how this would then lead to hydrocephalus. In addition to having a data analysis on initial extension of the tumor on patient presentation, a further explanation of which areas of tumor were left behind when a gross total resection was not possible would also assist in explaining the results. Authors’ response: I am sorry we did not mention this information. There were no cases with the residual tumor in the aqueduct. During the operation, the surgeons ensured regarding the adequacy of visualization of the aqueduct and CSF flow after tumor removal. Meanwhile, there is no residual tumor near the aqueduct and the residual tumors are located in the brain stem and the bottom of the fourth ventricle in failed-total resection cases on postoperative MRI. We have added this sentence (Page 14, line 296-299). 3. Further, the authors mentioned that endoscopic third ventriculostomy (ETV) was a consideration for patients with fourth ventricular obstruction. The paper does not address why none of the patients who eventually underwent VPS placement were or were not considered for ETV as this may have been able to avoid permanent CSF diversion through a shunt. Authors’ response: We do not routinely use ETV for hydrocephalus with fourth ventricle tumor, and this will be improved in the future. Thank you for this valuable comment. Reviewer #7 1. There is a basic assumption in this manuscript which may be fallacious: Regardless of pathology it is the anatomic extent of the tumor that determines hydrocephalus. Although using appropriate statistical analysis the office did not demonstrate significance of pathology, the subgroup's may be too small to provide a true "real world answer". Authors’ response: Thank you for this valuable comment. We have mentioned this in the limitations. (Page, line 282-294) 2. In the discussion the role of age and its implication for development of hydrocephalus is briefly reviewed but I believe this needs to be further expanded. It is not just age but the more aggressive nature of the tumors that we see in children under 5 years of age and particularly under 3 years of age with leptomeningeal dissemination that may increase the risk of hydrocephalus. The older patients in this study and the relatively small number of those with medulloblastoma may give a false impression of watch factors truly influence the development of hydrocephalus. Authors’ response: We have further expanded the part in the discussion (Page 13, line 230-240). Thank you for this valuable comment. 3. I would be curious if this finding would hold up if the authors limited the population studied 2 patients over 16 years of age, that is those that are anatomically adult. I am not certain that this finding would be seen in younger children, particular with medulloblastoma where the mean age is below that of the study population in this manuscript. Authors response: Superior tumor extension and subtotal resection were identified as independent risk factors for hydrocephalus after resection of tumor in the fourth ventricle in this study. But only subtotal resection was significantly associated with hydrocephalus when only patients older than 16 years were enrolled. This seems to be a type II error, which might be attributed to a smaller sample size when pediatric patients were excluded. Finally, we earnestly appreciate the Editor’s helpful work and hope that these answers and corrections will meet with approval. Once again, thank you very much for your comments and suggestions. Best regards. Yuekang Zhang Department of Neurosurgery, West China Hospital, Sichuan University, China E-mail: 2012zykyx@sina.cn Attachments Attachment Submitted filename: Response to Reviewers.docx https://doi.org/10.1371/journal.pone.0241853.r002
12 Oct 2020 Decision Letter - Michael C Burger, Editor PONE-D-20-23644R1 Risk factors for hydrocephalus following fourth ventricle tumor surgery: A retrospective analysis of 121 patients PLOS ONE Dear Dr. Zhang, Thank you for submitting your manuscript to PLOS ONE. After careful consideration, we feel that it has merit but does not fully meet PLOS ONE’s publication criteria as it currently stands. Therefore, we invite you to submit a revised version of the manuscript that addresses the points raised during the review process. Please add a paragraph into the discussion part of the manuscript where you explain whether or not less than 1.5 cc of residual tumor coating the floor of the fourth ventricle will necessitate ultimate CSF diversion. Please submit your revised manuscript by Nov 26 2020 11:59PM. If you will need more time than this to complete your revisions, please reply to this message or contact the journal office at plosone@plos.org. When you're ready to submit your revision, log on to https://www.editorialmanager.com/pone/ and select the 'Submissions Needing Revision' folder to locate your manuscript file. Please include the following items when submitting your revised manuscript: A rebuttal letter that responds to each point raised by the academic editor and reviewer(s). You should upload this letter as a separate file labeled 'Response to Reviewers'. A marked-up copy of your manuscript that highlights changes made to the original version. You should upload this as a separate file labeled 'Revised Manuscript with Track Changes'. An unmarked version of your revised paper without tracked changes. You should upload this as a separate file labeled 'Manuscript'. If you would like to make changes to your financial disclosure, please include your updated statement in your cover letter. Guidelines for resubmitting your figure files are available below the reviewer comments at the end of this letter. If applicable, we recommend that you deposit your laboratory protocols in protocols.io to enhance the reproducibility of your results. Protocols.io assigns your protocol its own identifier (DOI) so that it can be cited independently in the future. For instructions see: http://journals.plos.org/plosone/s/submission-guidelines#loc-laboratory-protocols We look forward to receiving your revised manuscript. Kind regards, Michael C Burger, M.D. Academic Editor PLOS ONE [Note: HTML markup is below. Please do not edit.] Reviewers' comments: Reviewer's Responses to Questions Comments to the Author 1. If the authors have adequately addressed your comments raised in a previous round of review and you feel that this manuscript is now acceptable for publication, you may indicate that here to bypass the “Comments to the Author” section, enter your conflict of interest statement in the “Confidential to Editor” section, and submit your "Accept" recommendation. Reviewer #1: All comments have been addressed Reviewer #2: All comments have been addressed Reviewer #4: All comments have been addressed Reviewer #5: All comments have been addressed Reviewer #7: (No Response) ******** 2. Is the manuscript technically sound, and do the data support the conclusions? The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented. Reviewer #1: Yes Reviewer #2: Yes Reviewer #4: Yes Reviewer #5: Yes Reviewer #7: Partly ****** 3. Has the statistical analysis been performed appropriately and rigorously? Reviewer #1: Yes Reviewer #2: Yes Reviewer #4: Yes Reviewer #5: I Don't Know Reviewer #7: Yes ****** 4. Have the authors made all data underlying the findings in their manuscript fully available? The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified. Reviewer #1: No Reviewer #2: Yes Reviewer #4: Yes Reviewer #5: No Reviewer #7: Yes ****** 5. Is the manuscript presented in an intelligible fashion and written in standard English? PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here. Reviewer #1: Yes Reviewer #2: Yes Reviewer #4: Yes Reviewer #5: Yes Reviewer #7: Yes ****** 6. Review Comments to the Author Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters) Reviewer #1: I recommend publication in its current form I recommend publication in its current form I recommend publication in its current form Reviewer #2: In my opinion, the authors have responded well to the reviewers comments, and the revised manuscript is improved compared to the original manuscript Reviewer #4: I believe the revisions improve the quality of the article. I believe the authors have answered the reviewers concerns to my satisfaction. Reviewer #5: (No Response) Reviewer #7: I still take issue with the comment that a gross total resection versus a near total resection is a significant indicator for the need of a shunt procedure particularly in younger children. I would urge the authors to further expand the discussion, particularly questioning whether less than 1.5 cc of residual tumor coating the floor of the fourth ventricle will necessitate ultimate CSF diversion. This is particularly pertinent since it has been well-established in the pediatric neuro-oncology literature that there is no survival advantage for gross total resection versus minimal residual disease ****** 7. PLOS authors have the option to publish the peer review history of their article (what does this mean?). If published, this will include your full peer review and any attached files. If you choose “no”, your identity will remain anonymous but your review may still be made public. Do you want your identity to be public for this peer review? For information about this choice, including consent withdrawal, please see our Privacy Policy. Reviewer #1: Yes: Ronald Benveniste Reviewer #2: Yes: Eirik Helseth Reviewer #4: Yes:** Lawrence M. Shuer, MD Reviewer #5: No Reviewer #7: No [NOTE: If reviewer comments were submitted as an attachment file, they will be attached to this email and accessible via the submission site. Please log into your account, locate the manuscript record, and check for the action link "View Attachments". If this link does not appear, there are no attachment files.] While revising your submission, please upload your figure files to the Preflight Analysis and Conversion Engine (PACE) digital diagnostic tool, https://pacev2.apexcovantage.com/. PACE helps ensure that figures meet PLOS requirements. To use PACE, you must first register as a user. Registration is free. Then, login and navigate to the UPLOAD tab, where you will find detailed instructions on how to use the tool. If you encounter any issues or have any questions when using PACE, please email PLOS at figures@plos.org. Please note that Supporting Information files do not need this step. https://doi.org/10.1371/journal.pone.0241853.r003
Revision 2
20 Oct 2020 Author Response Editor’s comments： 1. Please add a paragraph into the discussion part of the manuscript where you explain whether or not less than 1.5 cc of residual tumor coating the floor of the fourth ventricle will necessitate ultimate CSF diversion. Authors’ response: We have further expanded the part in the discussion (Page 14, line 288-298). Thank you for this valuable comment. Reviewers’ comments: Reviewer #1 1. I recommend publication in its current form Authors’ response: Thank you for the comments. Reviewer #2 1. In my opinion, the authors have responded well to the reviewers comments, and the revised manuscript is improved compared to the original manuscript. Authors’ response: Thank you for the comment. Reviewer #4 1. I believe the revisions improve the quality of the article. I believe the authors have answered the reviewers concerns to my satisfaction. Authors’ response: Thank you for the comment. Reviewer #5 (No Response) Reviewer #7 1. I still take issue with the comment that a gross total resection versus a near total resection is a significant indicator for the need of a shunt procedure particularly in younger children. I would urge the authors to further expand the discussion, particularly questioning whether less than 1.5 cc of residual tumor coating the floor of the fourth ventricle will necessitate ultimate CSF diversion. This is particularly pertinent since it has been well-established in the pediatric neuro-oncology literature that there is no survival advantage for gross total resection versus minimal residual disease. Authors’ response: We have further expanded the part in the discussion (Page 14, line 288-298). Thank you for this valuable comment. Attachments Attachment Submitted filename: Response to Reviewers.docx https://doi.org/10.1371/journal.pone.0241853.r004
22 Oct 2020 Decision Letter - Michael C Burger, Editor Risk factors for hydrocephalus following fourth ventricle tumor surgery: A retrospective analysis of 121 patients PONE-D-20-23644R2 Dear Dr. Zhang, We’re pleased to inform you that your manuscript has been judged scientifically suitable for publication and will be formally accepted for publication once it meets all outstanding technical requirements. Within one week, you’ll receive an e-mail detailing the required amendments. When these have been addressed, you’ll receive a formal acceptance letter and your manuscript will be scheduled for publication. An invoice for payment will follow shortly after the formal acceptance. To ensure an efficient process, please log into Editorial Manager at http://www.editorialmanager.com/pone/, click the 'Update My Information' link at the top of the page, and double check that your user information is up-to-date. If you have any billing related questions, please contact our Author Billing department directly at authorbilling@plos.org. If your institution or institutions have a press office, please notify them about your upcoming paper to help maximize its impact. If they’ll be preparing press materials, please inform our press team as soon as possible -- no later than 48 hours after receiving the formal acceptance. Your manuscript will remain under strict press embargo until 2 pm Eastern Time on the date of publication. For more information, please contact onepress@plos.org. Kind regards, Michael C Burger, M.D. Academic Editor PLOS ONE Additional Editor Comments (optional): Reviewers' comments: https://doi.org/10.1371/journal.pone.0241853.r005
Formally Accepted
9 Nov 2020 Acceptance Letter - Michael C Burger, Editor PONE-D-20-23644R2 Risk factors for hydrocephalus following fourth ventricle tumor surgery: A retrospective analysis of 121 patients Dear Dr. Zhang: I'm pleased to inform you that your manuscript has been deemed suitable for publication in PLOS ONE. Congratulations! Your manuscript is now with our production department. If your institution or institutions have a press office, please let them know about your upcoming paper now to help maximize its impact. If they'll be preparing press materials, please inform our press team within the next 48 hours. Your manuscript will remain under strict press embargo until 2 pm Eastern Time on the date of publication. For more information please contact onepress@plos.org. If we can help with anything else, please email us at plosone@plos.org. Thank you for submitting your work to PLOS ONE and supporting open access. Kind regards, PLOS ONE Editorial Office Staff on behalf of Dr. Michael C Burger Academic Editor PLOS ONE https://doi.org/10.1371/journal.pone.0241853.r006

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