METHOD
Identify relevant studies and study selection A systematic literature search was conducted on the 23th of December
2019, in the PubMed, Cochrane and EMBASE databases to identify articles
comparing outcome data from different surgical techniques for SBC
removal (syntax provided in Appendix 1). No restriction regarding
publication data and language were applied. This study is reported
according to the Preferred Reporting Items for Systematic Review and
Meta-analysis (PRISMA) statement (14).
Study selectionTwo authors (S.M., R.M.) independently screened the retrieved articles
on title and abstract using pre-defined inclusion and exclusion criteria
(Fig. 1). The selected articles were read in full-text by the
aforementioned two authors. Only studies comparing different surgical
techniques in one cohort of patients were selected. The reference lists
of the selected articles were reviewed for a cross-reference check to
select relevant studies that were not identified in the initial search.
All authors were involved in the discussion leading to final article
inclusion. Disagreement between authors was solved by discussion.
Data extractionData from all included studies was independently extracted by the
authors. The predefined included data contained: year of publication,
number of included patients (total and patients with SBC specifically),
occurrence of bilateral anomalies, pre-operative SBC infection, gender,
age at surgery, pre-operative imaging with: computed tomography,
magnetic resonance imaging or ultrasound, operation technique, operating
time, incision type and length, follow up duration, recurrence and
complication rates, and scar satisfaction.
Quality assessment Four authors (S.M., H.B., E.v.d.V. and M.v.d.A.) critically appraised
selected articles regarding directness of evidence (DoE) and risk of
bias (RoB) (Table 1). We assessed the DoE using three criteria: 1)
domain: studies comparing surgical techniques for SBC removal 2)
determinant: clear description of the selected surgical technique and 3)
surgical outcome: report on recurrence and complication rates. To
perform RoB assessment on the selected studies, authors applied an
appraisal tool derived from the Cochrane risk of bias Tool (15) . Each
criterion was rated satisfactory (●), partly satisfactory (○), or
unsatisfactory (-) (explanatory legend of Table 1). Overall DoE was
rated as high (H), moderate (M) or low (L). Only studies with a high
directness of evidence were selected for final inclusion. No studies
were excluded based on RoB, adhering to the Grading of Recommendations
Assessment, Development and Evaluation (GRADE) system (16).
Data synthesis Pooling of data was considered in case of homogeneity between studies
(if I2 was <50%)(17).
RESULTS An overview of the study selection process and reasons for exclusion is
presented in figure 1. (flowchart). Four articles had a high DoE and
were included for final selection. This resulted in the inclusion of the
treatment of 140 cysts. No patients with bilateral cysts were included.
These four studies (6,9,10,12) contained two randomized controlled
trails (RCTs) and two prospective trials. For an overview of the
included surgical techniques see Figure 2 and the description in
Appendix 2. Two authors (9,10) were contacted to provide additional
information regarding the applied incision type, however, no additional
information was provided. The inclusion dates of the patient cohorts of
Chen et al. 2012 (10) and Chen et al. 2014 (9) did not
overlap and therefore, both studies were included in the current review.
Meta-analysis was not performed in this review due to heterogeneity
regarding: baseline characteristics, study design and applied surgical
techniques.
Data extraction: Table 2 shows the data extraction of four included studies that
directly compared outcomes between conventional surgery and modern
removal techniques in patients presenting with unilateral SBCs. All
patients from these studies underwent pre-operative imaging using
CT-scan or ultrasound scanning and pre-operative fine needle cytology to
confirm the diagnosis (data not shown). Chen et al. (10) compared
SBC removal results between conventional, curvilinear, cervical
incisions along a natural skin crease (3-4 cm below the lower border of
the mandible) to the endoscopic RAHI technique. Adult patients were
randomly assigned between both techniques (Table 2). None of the
included patients suffered from a pre-operative SBC infection. No
recurrence occurred during a follow up of at least six months. There was
no significant difference in operating time between both techniques;
however, there was a significantly (p = < .001) higher
scar satisfaction rate in the RAHI group. Scar satisfaction was measured
six months postoperatively using a visual analog scale ranging from
0-10. Chen et al. (9) compared SBC removal using a curvilinear
cervical incision along a natural skin crease (4-5 cm below the lower
border of the mandible) to an endoscopic approach of the lateral neck
using two randomly assigned patient groups. Twenty adult patients were
assigned to the conventional cervical incision, whereas 21 patients were
assigned to the endoscopic lateral neck approach. None of the included
patients suffered from a pre-operative SBC infection. No recurrence
occurred during a follow up of at least six months. Although no
significant difference in operating time was reported between both
groups, incision length and scar satisfaction did significantly
(p < .05) differ in favor of the endoscopic technique.
Scar satisfaction was measured six months postoperatively using a visual
analog scale ranging from 0-10. Ahn et al . (12) compared SBC
removal outcomes between a conventional approach (by making a
curvilinear incision directly over the anomaly) and an open RAHI
approach in a prospective case control study. Thirteen adult patients
were operated by the open RAHI approach while 17 adult patients
underwent a (conventional) cervical incision. Ahn et al. reported
a pre-operative SBC infection rate of 30.8% in the patients who were
operated using the open RAHI technique. No recurrence occurred during a
follow up of three months. Of the patients who underwent conventional
surgery, 11.8% suffered from a postoperative hematoma or seroma,
compared to 7.7% of the patients who underwent open RAHI surgery
(non-significant difference ). Only patients of the open RAHI
group suffered from postoperative neurological damage that spontaneously
resolved (23.1%). The retro-auricular approach entailed significantly
longer operating time (p = .019), however, resulted in
significantly higher scar satisfaction (p= < .001).
Scar satisfaction was measured three months postoperatively using a
visual analog scale ranging from 0-10. Iaremenko et al. (6)
compared SBC removal outcomes between a conventional approach (by making
a skin incision 2.0-2.5 centimeter below the lower border of the
mandible) and an endoscopic occipital approach using a controlled study
design. The latter technique is comparable to the endoscopic RAHI
technique of Chen et al. (10) from a surgical perspective.
Twenty-two adult patients were operated by the occipital endoscopic
approach, while 22 adult patients underwent a (conventional) cervical
incision. No recurrence occurred during a follow up of six months. Of
the conventional group, 4.5% developed a hematoma and 4.5% developed
temporary neurological damage. In the occipital approach group 27.3%
reported temporary pain and difficulty at sideward arm raise. The
endoscopic approach resulted in a significantly higher scar satisfaction
(p = .05), but took significantly longer operating time (p
= .05). Scar satisfaction was measured six months postoperatively using
the criteria ‘emotional component’ of the ‘Attitude to health’
questionnaire. Since no recurrence was reported in any of the included
studies, no data regarding revision surgery were retrieved.
DISCUSSION
Summary of findings: In this systematic literature
review, we compared the clinical outcome (complication and recurrence
rates and scar satisfaction) of SBC removal between conventional surgery
and less invasive removal techniques (endoscopic surgery or
open/endoscopic RAHI). Only four studies (6,9,10,12) were identified
that compared the conventional technique with newer techniques within
one patient cohort. All of these included studies are of low quality due
to: short follow up periods, small patient groups and a study design
prone to bias due to both selection criteria (e.g. no inclusion of
pre-operatively infected cysts) and lack of blinding. Since evidence is
scarce, it remains difficult to provide evidence-based surgical
treatment advice.
Results demonstrate that surgical treatment of SBC results in a
complication rate ranging between 0 to 27.3%. The most reported
complications were temporary earlobe hypoesthesia in patients who
underwent endoscopic or (endoscopic) RAHI surgery (most likely due to
perioperative greater auricular nerve manipulation), temporary pain and
difficulty of sideward arm raise (most likely resulting from spinal
accessory nerve manipulation). No permanent neurological damage was
reported. Surgical treatment provides a definitive treatment with no
reported recurrence using either one of the techniques. Studies that
compared both techniques within the same adult patient cohort
demonstrated that both the (endoscopic) RAHI approach as well as other
endoscopic techniques resulted in higher scar satisfaction. Therefore,
available evidence demonstrates that application of less invasive SBC
removal techniques to treat uninfected second branchial cleft cysts
results in relatively higher, temporary complication rates, however,
with a significantly higher scar satisfaction. An interesting result,
since the operating area is in a prominently visible location in a
patient population containing young adults.
Two included studies (9,10) excluded patients presenting with fistulas
and sinuses, pre-operatively infected SBCs and patients who underwent
prior neck surgery or radiotherapy. Only Ahn et al. reported on
open RAHI treatment of patients with pre-operatively infected SBCs.
Although 30.8% of these patients suffered from a pre-operative
infection, no relatively higher complication rate was reported for this
population compared to the cervical incision group. Iaremenko et
al. did not report whether any pre-operatively infected SBC were
included in their study cohort.
Comparison with other studies and techniques:
This is the first literature review reporting on the clinical outcome
of SBC removal comparing different surgical techniques. Cohort
studies(9,11,13) investigating either open RAHI or endoscopic RAHI found
similar results: absence of recurrence in combination with low
complication rates, with an average follow up of (at least) 6, 14.5 and
42 months respectively. The only reported complications in open RAHI
surgery were temporary hypoesthesia of the earlobe and hypertrophic
scars.
In previous studies, conventional second branchial arch anomaly removal
techniques have been studied intensively. Appendix 3 shows an overview
of these studies that were identified through the same literature
search. This Appendix also includes patients presenting with fistulas
and sinuses (mostly children). Precise data regarding the distribution
of (included) cysts, sinuses and fistulas, side of the anomalies,
description of the used surgical technique or duration of follow up is
lacking in most studies (Appendix 3). Only retrospective studies were
identified with a complication rate ranging between 0 and 32% and a
recurrence rate ranging between 0 and 4.9%. These recurrence rates were
reported when follow up lasted till four or even ten years (18,19).
Therefore, the follow-up of the included studies in this review (ranging
between 3-24 months) could be too short to identify recurrence following
surgery. Long-term recurrence rates are of major importance because
recurrence of disease will cause high morbidity and can make revision
surgery complex. Furthermore, this short follow up could also affect the
reported scar satisfaction since three to six months after surgery the
final scar result may not be visible yet.
Multiple authors (20–22) refer to Deane et al. (23) regarding
recurrence percentages: Deane et al described the results of a
retrospective study (performed between 1954 and 1975) including 274
patients with branchial cleft remnants below the mandible. The surgical
technique is described as a local excision of the lesion (plus tract
when necessary). The reported recurrence rate was 2.7% in patients
without a prior infection, 14% in patients with a pre-operative
infection and 21.2% in patients who underwent revision surgery. The
average follow up duration was 12.4 years (1-22 years). No distinction
between second, third and fourth branchial anomalies was made.
Quality of evidence and potential biases
The overall quality of the included studies was low (IIb -IV regarding
the Oxford Centre for Evidence-Based Medicine guidelines ): only
two studies used a RCT to compare the clinical outcome between surgical
techniques. In these RCTs, selection bias could not be ruled out since
lack of blinding. The quality of evidence regarding SBAA removal was
mostly affected by small patient cohorts resulting in Type II error
(i.e., failing to reject a false null hypothesis), short follow up,
unclear inclusion criteria and selective reporting.