Free paper abstracts for the 20th World Congress of Neurosurgery are submitted online by the deadline, and the presenting author of each accepted abstract must complete paid registration within 10 working days of the acceptance letter. The Congress takes place on 16–20 November 2027 at the Bali Nusa Dua Convention Center (BNDCC), Bali, Indonesia.

All deadlines end at 23:59 Bali time (WITA, UTC+8).

Authors select one primary category for each abstract, and the Scientific Committee may move an abstract to a more suitable category.

Abstracts are accepted only through the online submission portal. Abstracts sent by email, post or any other route will not be considered.

The author must complete the online submission form for each abstract. An incomplete form cannot be accepted. The form asks for:

1. Author information: Full name, email address, institution and country of the submitting author, presenting author and all co-authors
2. Topic category: The one category from the topic list that best matches the abstract
3. Preferred presentation format: Oral presentation or ePoster
4. Abstract details: Title, keywords and abstract text
5. Declarations: Conflicts of interest and acceptance of these guidelines

The following rules apply to all submissions:

1. All abstracts must be written and presented in English
2. There is no limit on the number of abstracts an author may submit
3. A presenting author may present a maximum of 2 accepted abstracts
4. Each abstract must name one presenting author, who is responsible for all correspondence
5. The submitting author must confirm that all co-authors have approved the content
6. The presentation format selected in the form is a preference only. The Scientific Committee makes the final decision
7. Abstracts may be edited until the submission deadline. After that date, no changes to content, authors or category are allowed
8. Spelling, grammar and formatting will not be corrected by the Committee and will appear as submitted

The abstract body has a maximum of 300 words and must use the five headings below. The title, author details and keywords do not count toward this limit.

The following are not permitted in the abstract body:

1. Author names, institutions or other details that identify the authors
2. Tables, figures or references
3. Trade names, company names or promotional content; generic terms must be used
4. Unexplained abbreviations; each must be defined at first use, except standard units
5. Statements such as "results will be discussed at the presentation

All data must be collected and analysed by the submission deadline. Abstracts without completed results will be rejected.

By submitting an abstract, the authors confirm that the work is their own and meets each requirement below:

1. Originality: The work must not have been published in a peer-reviewed journal or presented at an international meeting before submission
2. Ethics approval: Studies involving patients, human tissue or animals must have the required ethics approval or exemption
3. Patient privacy: Consent must be obtained where required, and no information may identify a patient
4. Conflicts of interest: Conflicts of interest: All financial and commercial relationships must be declared in the portal and on the opening slides or ePoster
5. Artificial intelligence: Artificial intelligence: Any use of AI tools in writing the abstract must be declared, and AI tools cannot be listed as authors
6. Research integrity: Research integrity: Plagiarism, fabricated data, falsified data or duplicate submission will result in rejection or removal at any stage

Each abstract is scored by independent reviewers without access to author names or institutions. The Committee aims for high

scientific quality and a wide geographic spread of presenters. Abstracts are scored on six criteria:

1. Significance for neurosurgery
2. Innovation in ideas, methods or approach
3. Rigour of methods
4. Quality of the findings presented
5. Implications for research, practice or policy
6. Clarity of writing

The acceptance letter is sent by email to the submitting author and states the abstract number and presentation format. It is treated as received on the date it is sent, so authors should check their spam folders. Authors with no decision by 16 August 2027 should contact the Scientific Secretariat immediately.

The Committee's decisions on acceptance, category and format are final and not open to appeal. Acceptance does not cover registration, travel, accommodation or any other cost.

The presenting author of every accepted abstract must register and pay in full within 10 working days of the acceptance letter, or the abstract is automatically withdrawn. No extension or reinstatement will be granted.

For this rule:

1. Working days are Monday to Friday, excluding Indonesian national public holidays
2. Counting starts on the first working day after the acceptance letter is sent
3. Registration is complete only when full payment has been made and confirmed by the Secretariat. A registration form alone does not count
4. Sponsored authors must have their payment made within the same period

For example, a letter sent on Monday 16 August 2027 gives a deadline of 23:59 WITA on Tuesday 31 August 2027. This skips the 17 August public holiday and assumes no other holiday falls in that period.

The following regulations also apply without exception:

Accepted abstracts are presented as oral papers or ePosters, and each presenter receives the session details before the Congress

1. Oral presentation category A:8 minutes for the talk and 2 minutes for discussion, using 16:9 slides
2. Oral presentation category B:5 minutes for the talk and 2 minutes for discussion, using 16:9 slides
3. ePoster:One potrait digital poster in the template supplied by the Committee
4. Content:The presentation must match the accepted abstract and must not contain commercial promotion
5. Certificates:Certificates are issued only to authors who present

By submitting, authors allow the organisers to publish the abstract as submitted in the Congress programme, abstract book, website and app. Authors must have the right to grant this permission.

Authors may withdraw an abstract by writing to the Scientific Secretariat by 30 September 2027.

Registration fees follow the Congress cancellation and refund policy and are not refunded automatically when an abstract is withdrawn or removed.

For abstract questions, contact freepaper@wfns2027bali.org

For registration and payment questions, contact registration@wfns2027bali.org