Interventional procedure overview of Transvenous embolisation for spontaneous intracranial hypotension caused by a cerebrospinal fluid-venous fistula

Appendix A: Methods and literature search strategy

Methods and literature search strategy 

NICE has identified studies and reviews relevant to transvenous embolisation for the treatment of cerebrospinal fluid-venous fistula (CSFVF), a cause of spontaneous intracranial hypotension (SIH).  

Search strategy design and peer review 

This search report is informed by the Preferred Reporting Items for Systematic reviews and Meta-Analyses literature search extension (PRISMA-S). 

A NICE information specialist ran the literature searches on 02 June 2025. See the search strategy history for the full search strategy for each database. Relevant published studies identified during consultation or resolution that are published after this date may also be considered for inclusion. 

The principal search strategy was developed in MEDLINE ALL (Ovid interface). It was adapted for use in each of the databases listed in Table 4, taking into account the database's size, search functionality and subject coverage. The MEDLINE ALL strategy was quality assured by a NICE senior information specialist. All translated search strategies were peer reviewed to ensure their accuracy. The quality assurance and peer review procedures were adapted from the Peer Review of Electronic Search Strategies (PRESS) 2015 evidence-based checklist. 

Review management 

The search results were managed in EPPIReviewer version 5 (EPPIR5). Duplicates were removed in EPPIR5 using a 2 step process. First, automated deduplication was done using a high-value algorithm. Second, manual deduplication was used to assess low-probability matches. All decisions about inclusion, exclusion and deduplication were recorded and stored. 

Limits and restrictions 

The search was not limited by date or language. The CENTRAL database search removed trial registry records and conference material. The Embase search excluded conference material. 

The limit to remove animal studies in the searches is standard NICE practice, which has been adapted from Dickersin K, Scherer R, Lefebvre C (1994) Systematic Reviews: Identifying relevant studies for systematic reviews. BMJ 309(6964): 1286. 

Main search 

Table 4 Main search results 

Search strategy history 

MEDLINE ALL search strategy 

1 Cerebrospinal Fluid Pressure/ 1948  

2 Cerebrospinal Fluid Leak/ 2308  

3 Intracranial Hypotension/ 1711  

4 headache/ 32977  

5 (cerebrospinal fluid* venous fistula* or CSF-VF or CSFVF or CVF).tw. 1334  

6 ((CSF or cerebrospinal fluid*) adj4 (leak* or drainage* or hypotension* or hypovolemia* or fistula*)).tw. 13767  

7 (spontaneous adj4 intracranial adj4 hypotension*).tw. 1375  

8 (low pressure adj4 headache*).tw. 91  

9 (cerebrospinal fluid* adj4 volume adj4 depletion*).tw. 9  

10 ((tear or rupture) adj4 (dura mater or dural or pachymeninx or tentorium cerebelli or falx cerebri or falx cerebelli)).tw. 1207  

11 or/1-10 50858   

12 Embolization, Therapeutic/ 38808  

13 ((transvenous or paraspinal vein*) adj10 emboli?ation*).tw. 1122  

14 embolotherap*.tw. 814  

15 (endovascular adj4 transvenous).tw. 170  

16 (endovascular adj4 therap*).tw. 8674  

17 liquid embolic*.tw. 829  

18 or/12-17 47524  

19 Onyx Liquid Embolic System*.tw. 33  

20 11 and 18 281  

21 19 or 20 314  

22 animals/ not humans/ 5307605  

23 21 not 22 314 

Embase search strategy 

1 cerebrospinal fluid pressure/ 4683  

2 *liquorrhea/ 2574  

3 intracranial hypotension/ 3333  

4 cerebrospinal fluid fistula/ 3911  

5 *headache/ 35399  

6 (cerebrospinal fluid* venous fistula* or CSF-VF or CSFVF or CVF).tw. 2174  

7 ((CSF or cerebrospinal fluid*) adj4 (leak* or drainage* or hypotension* or hypovolemia* or fistula*)).tw. 18966  

8 (spontaneous adj4 intracranial adj4 hypotension*).tw. 1782  

9 (low pressure adj4 headache*).tw. 151  

10 (cerebrospinal fluid* adj4 volume adj4 depletion*).tw. 11  

11 ((tear or rupture) adj4 (dura mater or dural or pachymeninx or tentorium cerebelli or falx cerebri or falx cerebelli)).tw. 1658  

12 or/1-11 64939  

13 artificial embolization/ 74225  

14 ((transvenous or paraspinal vein*) adj10 emboli?ation*).tw. 1379  

15 embolotherap*.tw. 1239  

16 (endovascular adj4 transvenous).tw. 222  

17 (endovascular adj4 therap*).tw. 14105  

18 liquid embolic*.tw. 1259  

19 or/13-18 88111  

20 Onyx Liquid Embolic System*.tw. 51  

21 12 and 19 320  

22 20 or 21 371  

23 Nonhuman/ not Human/ 5733174  

24 22 not 23 369  

25 (conference abstract* or conference review or conference paper or conference proceeding).db,pt,su. 6275024  

26 24 not 25 274  

27 limit 26 to "remove clinical trial (clinicaltrials.gov) records" 269 

Cochrane Library (CDSR and CENTRAL) search strategy 

#1 MeSH descriptor: [Cerebrospinal Fluid Pressure] explode all trees 525  

#2 MeSH descriptor: [Cerebrospinal Fluid Leak] explode all trees 94  

#3 MeSH descriptor: [Intracranial Hypotension] explode all trees 9  

#4 MeSH descriptor: [Headache] explode all trees 3184  

#5 (cerebrospinal fluid* venous fistula* or CSF-VF or CSFVF or CVF) 129  

#6 ((CSF or cerebrospinal fluid*) near/4 (leak* or drainage* or hypotension* or hypovolemia* or fistula*)) 2062  

#7 (spontaneous near/4 intracranial near/4 hypotension*) 6  

#8 (low pressure near/4 headache*) 106  

#9 (cerebrospinal fluid* near/4 volume near/4 depletion*) 0  

#10 ((tear or rupture) near/4 (dura mater or dural or pachymeninx or tentorium cerebelli or falx cerebri or falx cerebelli)) 82  

#11 {or #1-#10} 6036  

#12 MeSH descriptor: [Embolization, Therapeutic] explode all trees 1299  

#13 ((transvenous or paraspinal vein*) near/10 emboli?ation*) 182  

#14 embolotherap* 46  

#15 (endovascular near/4 transvenous) 1  

#16 (endovascular near/4 therap*) 1617  

#17 liquid embolic* 35  

#18 {or #12-#17} 3019  

#19 Onyx Liquid Embolic System* 6  

#20 #11 and #18 12  

#21 #19 or #20 17  

#22 "conference":pt or (clinicaltrials or trialsearch):so 824537  

#23 #21 not #22 14  

INAHTA HTA Database search strategy 

#1 "Cerebrospinal Fluid Pressure"[mh] 1 

#2 "Cerebrospinal Fluid Leak"[mh] 0 

#3 "Intracranial Hypotension"[mh] 0 

#4 "Headache"[mh] 44 

#5 (cerebrospinal fluid* venous fistula* or CSF-VF or CSFVF or CVF) 0 

#6 ((CSF or cerebrospinal fluid*) AND (leak* or drainage* or hypotension* or hypovolemia* or fistula*)) 29 

#7 (spontaneous AND intracranial AND hypotension*) 0 

#8 (low pressure AND headache*) 3 

#9 (cerebrospinal fluid* AND volume AND depletion*) 0 

#10 ((tear or rupture) AND (dura mater or dural or pachymeninx or tentorium cerebelli or falx cerebri or falx cerebelli)) 0 

#11 #1 or #2 or #3 or #4 or #5 or #6 or #7 or #8 or #9 or #10  76 

#12 "Embolization, Therapeutic"[mh] 72 

#13 ((transvenous or paraspinal vein*) AND or emboli?ation*) 2 

#14 (embolotherap*) 43 

#15 (endovascular AND transvenous) 0 

#16 (endovascular AND therap*) 38 

#17 liquid embolic* 2 

#18 #12 or #13  or #14 or #15 or #16 or #17 103 

#19 #11 and #18 2 

#20 Onyx Liquid Embolic System* 2 

#21 #19 or #20 2 

Inclusion criteria 

The following inclusion criteria were applied to the abstracts identified by the literature search. 

If selection criteria could not be determined from the abstracts the full paper was retrieved. 

Potentially relevant studies not included in the main evidence summary are listed in Appendix B: Other relevant studies.

Find out more about how NICE selects the evidence for the committee.