Neurosurg Focus / Volume 35 / September 2013
Neurosurg Focus 35 (3):E3, 2013
rigeminal neuralgia is one of the few chronic neuro-
pathic pain syndromes for which very effective and
diverse surgical treatments are available. Recent
international guidelines9 and systematic reviews39,46,47
identified the shortage of high-quality evidence that can
enable patients, physicians, and health policy makers to
select the most effective and efficient surgical treatment.
Spatz et al.37 reported that patients found it difficult to
choose among surgical treatments for TN for the same
reasons. It is essential that high-quality evidence that
compares different modalities of treatments is available
to provide reliable and balanced selection of a surgical
treatment by both patients and health care providers.
Wente et al.43 analyzed the contents of leading surgical
journals and found that only 3% of articles were reports
Proposal for evaluating the quality of reports of surgical
interventions in the treatment of trigeminal neuralgia: the
Surgical Trigeminal Neuralgia Score
HaritH akram, F.r.C.S.(Neuro.Surg),1 Bilal mirza, PH.D.,1
Neil kitCHeN, F.r.C.S.(SN),1 aND JoaNNa m. zakrzewSka, F.F.P.m.r.C.a.2
1Victor Horsley Department of Neurosurgery, The National Hospital for Neurology and Neurosurgery, Queen
Square; and 2Division of Diagnostic, Surgical and Medical Sciences, Eastman Dental Hospital, University
College London Hospitals National Health Service Foundation Trust, London, United Kingdom
Object. The aim of this study was to design a checklist with a scoring system for reporting on studies of surgical
interventions for trigeminal neuralgia (TN) and to validate it by a review of the recent literature.
Methods. A checklist with a scoring system, the Surgical Trigeminal Neuralgia Score (STNS), was devised
partially based on the validated STrengthening the Reporting of OBservational studies in Epidemiology (STROBE)
criteria and customized for TN after a literature review and then applied to a series of articles. These articles were
identified using a prespecified MEDLINE and Embase search covering the period from 2008 to 2010. Of the 584
articles found, 59 were studies of interventional procedures for TN that fulfilled the inclusion criteria and 56 could be
obtained in full. The STNS was then applied independently by 3 of the authors.
Results. The maximum STNS came to 30, and was reliable and reproducible when used by the 3 authors who
performed the scoring. The range of scores was 6–23.5, with a mean of 14 for all the journals. The impact factor
scores of the journals in which the papers were published ranged from 0 to 4.8. Twenty-four of the studies were pub-
lished in the Journal of Neurosurgery or in Neurosurgery. Studies published in neurosurgical journals ranked higher
on the STNS scale than those published in nonneurosurgical journals. There was no statistically significant correla-
tion between STNS and impact factors. Stereotactic radiosurgery (n = 25) and microvascular decompression (n = 15)
were the most commonly reported procedures.
The diagnostic criteria were stated in 35% of the studies, and 4 studies reported subtypes of TN. An increasing
number of studies (46%) used the recommended Kaplan-Meier methodology for pain survival outcomes. The follow-
up period was unclear in 8 studies, and 26 reported follow-ups of more than 5 years. Complications were reported
fairly consistently but the temporal course was not always indicated. Direct interview, telephone conversation, and
questionnaires were used to measure outcomes. Independent assessment of outcome was only clearly stated in 7 stud-
ies. Only 2 studies used the 36-Item Short Form Health Survey to measure quality of life and 4 studies reported on
the severity of preoperative pain. The Barrow Neurological Institute pain questionnaire was the most commonly used
outcome measure (n = 13), followed by the visual analog scale.
Conclusions. Similar to the STROBE criteria that provide a checklist of items that should be included in reports
of observational studies in general, the authors’ suggested checklist for the STNS could help editors and reviewers
ensure that quality reports are published, and could prove useful for colleagues when reporting their results specifi-
cally on the surgical management of TN. It would help the patient and clinicians make a decision about selecting the
appropriate neurosurgical procedure.
key worDS • facial pain • Gamma Knife • microvascular decompression •
Surgical Trigeminal Neuralgia Score • stereotactic radiosurgery • trigeminal neuralgia
Abbreviations used in this paper: BNI = Barrow Neurological
Institute; BPI = Brief Pain Inventory; GKS = Gamma Knife surgery;
IASP = International Association for the Study of Pain; IF = impact
factor; MVD = microvascular decompression; QOL = quality of
life; RCT = randomized controlled trial; SF-36 = 36-Item Short
Form Health Survey; STNS = Surgical Trigeminal Neuralgia Score;
STROBE = STrengthening the Reporting of OBservational studies
in Epidemiology; TN = trigeminal neuralgia.
See the corresponding editorial in this issue (E4).
H. Akram et al.
Neurosurg Focus / Volume 35 / September 2013
of RCTs, and of those, 44% compared different surgical
procedures and 56% compared medical therapies in sur-
gical patients. Of the neurosurgical RCTs, only 52% were
considered to be of good quality.34 Similar trends were
found in a Cochrane review on neurosurgical interven-
tions for TN. Of 11 RCTs, only 3 were considered ap-
plicable in practice.
Importantly, no studies addressed MVD, the most ad-
vocated procedure for treatment of TN.46 Using evidence
from nonrandomized interventions requires very care-
fully designed trials and reporting. A Health Technology
Assessment report by Deeks et al.10 provided guidelines
for assessment of non-RCTs, which were developed fur-
ther by Zakrzewska and Lopez47 for reporting surgical
outcome in TN. The guidelines task force used these, but
stipulated that outcomes needed to be assessed by meth-
ods independent of the operator and that this needed to be
clearly stated. These guidelines have been used by several
Furthermore, Schriger and Altman,35 in their British
Medical Journal editorial, suggested that postpublication
review of the medical literature was inadequate because
letter writing was not considered rewarding, and therefore
either the existence or the lack of letters to the editor is
not an indicator of “read” status; perhaps many papers
remain unread and their results unused. It has been postu-
lated that authors, when challenged about their results (for
example when performing systematic reviews), often do
not provide sufficient answers,34 and this is a significant
error; the British Medical Journal issue of January 2012
highlighted how missing data and incomplete reporting
can harm patients.17 Given the difficulty of performing
RCTs of widely accepted surgical techniques, it is in-
creasingly important to ensure that surgical reports are
written to uniform standards, allowing results to be used
in meta-analyses.5 Rughani et al.31 showed clearly how
different conclusions can be reached when using national
databases when compared with small series on TN.
It is increasingly necessary to ensure that all reports
are written using a similar structure so that they can be
compared; this led to the Consolidated Standards of Re-
porting Trials (CONSORT) statement in 1996 for the
reporting of RCTs, which has now been accepted by all
the major journals.2 However, not all studies are RCTs,
and it has been increasingly recognized that these reports
also need a more structured format. This then led to the
Statement for Reporting Studies of Diagnostic Accuracy
(STARD).3 However, this still did not cover all types of
studies, and in 2007 a group of epidemiologists, meth-
odologists, statisticians, researchers, and journal editors
put forward a proposal for how reporting of observational
studies could be improved—this was called the STROBE41
statement (http://www.strobe-statement.org/). This state-
ment is now being increasingly endorsed by both medical
and surgical journals, and may be the template that could
be used for reporting TN studies.
Aim of Study
The aim of this study was to put forward a checklist
and a scoring system in line with the STROBE checklist
for quality assessment of papers that report specifically
on surgical treatments of TN, to improve the quality of
those reports and aid authors and editors.
MEDLINE and Embase databases were searched for
publications reporting surgical therapies for TN in the pe-
riod between January 2008 and January 2010. The search
strategy used was based on one used for a Cochrane sys-
tematic review46 and modified according to the criteria
1. Papers reporting primary outcome parameter: ef-
fect on pain after surgery.
2. Idiopathic TN.
3. Prospective and retrospective studies.
4. Randomized clinical trials.
5. Language: English.
6. All gasserian ganglion and posterior fossa proce-
7. Redo surgery; that is, separate reports of patients
who had 1 prior procedure.
1. Technical, anatomical, nontrial experiments, eco-
nomic, or methodological reports.
2. Reviews, editorials, surveys, guidelines, or com-
3. Case reports including < 5 patients.
4. Non-TN papers.
5. Symptomatic (secondary) TN or TN with multiple
6. Peripheral treatments distal to the gasserian gan-
Once the papers were identified the titles and ab-
stracts were then read independently by 2 authors (H.A.
and J. Z.). If the abstract fulfilled the criteria or there were
insufficient data in the abstract, the full papers were ob-
tained and read prior to selection.
A checklist and scoring system, the STNS (Table
1), was devised based on the STROBE statement, the
report by Deek et al.,10 previous recommendations from
Zakrzews ka and Lopez in 2003,47 the TN guidelines
committee, and subsequent use of the latter recommen-
dations in other reports.9,39 A range of scores from 0 to 30
was then applied to the papers that fulfilled the inclusion
criteria, with scores > 25 being considered high quality.
The results were presented at the Society of British Neu-
rological Surgeons’ scientific meeting in Leeds in Sep-
tember 2012. Feedback from the discussion was used to
refine the scoring system further.
A randomization software program (RandomAl-
locations Software version 1.0, M. Saghaei, Department
of Anesthesia, Isfahan University of Medical Sciences)
was used to randomize the papers to 3 equally distrib-
uted groups to be scored by 3 of the authors (H.A., B.M.,
J.Z.). Ten percent of the scored papers were redistributed
among the 3 authors, in such a way that no author re-
viewed the same paper twice, for validation and consis-
Neurosurg Focus / Volume 35 / September 2013
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Manuscript submitted May 9, 2013.
Accepted June 6, 2013.
Please include this information when citing this paper: DOI:
Address correspondence to: Harith Akram, F.R.C.S.(Neuro.
Surg), Victor Horsley Department of Neurosurgery, The National
Hospital for Neurology & Neurosurgery, Queen Square, London
WC1N 3BG, United Kingdom. email: email@example.com.