Research Article
The Lateral “Backdoor” Approach to Open Thyroid Surgery: A Comparative Study
Singaporewalla RM1*, Tan BC1 and Rao AD1
Department of Surgery, Khoo Teck Puat Hospital, Singapore
*Corresponding author: Singaporewalla RM, Department of Surgery, Khoo Teck Puat Hospital, 90 Yishun Central, Singapore
Published: 18 Jul, 2017
Cite this article as: Singaporewalla RM, Tan BC, Rao AD.
The Lateral “Backdoor” Approach to
Open Thyroid Surgery: A Comparative
Study. Clin Surg. 2017; 2: 1571.
Abstract
Introduction: The traditionally taught technique for conventional open thyroidectomy is via a
midline splitting of the strap muscles following a skin crease neck incision – midline approach (ma).
The lateral “backdoor” approach (la) uses the same central neck incision but approaches the thyroid
gland between the anterior border of sternocleidomastoid (scm) and strap muscles. This technique
is usually reserved for re-do thyroid surgery. We compared the results of the two approaches in
patients undergoing conventional thyroidectomy for the first time.
Methods: A case-control study was performed on 90 patients undergoing conventional open
thyroidectomy from 2012 to 2014. The first 45 patients underwent ma and subsequent 45 patients
underwent la. All patients were given 10 ml of 1% marcaine infiltration in to the neck incision
before closure. Basic demographic data, operative time, incision length, weight of gland, need
for transection of strap muscles and complications were recorded. Revision thyroid surgery and
minimally invasive thyroid operations were excluded.
Results: The demographics, operative timing, gland weight and incisional length showed no
significant difference. Post-Operative pain was significantly lower in the la group. Patients (5),
(11%) in ma group needed horizontal transection of strap muscles to extract large goitres compared
to 1 patient (2.2%) in the la group. no major complications occurred in either group.
Conclusion: The la method is as safe as the midline technique with comparable operative time
and significantly lower pain scores. It avoids midline separation and suturing of strap muscles and
reduces the need for strap muscle transection to removal large goitres.
Keywords: Lateral approach; Backdoor; Open thryoidectomy; Sternomastoid
Introduction
Thyroidectomy is the commonest endocrine surgical procedure. The traditionally taught technique for conventional thyroidectomy is via midline splitting of strap muscles (midline approach-ma) [1]. Lateral approach (la) uses the same central neck incision but approaches thyroid gland posterolaterally between the anterior border of sternocleidomastoid (scm) and strap muscles. It is also known as the sternomastoid or ‘backdoor” or lateral approach (la) to the thyroid gland [2- 4]. The critical structures that require identification and preservation in thyroid gland surgery such as parathyroid glands and recurrent laryngeal nerves are poster laterally located in relation to the thyroid lobe. La allows an easier access in delivering the thyroid gland into surgical field for easier identification of these critical structures with minimum retraction and pulling of strap muscles [2] this technique is usually reserved for re-do thyroid surgery performed previously using them due to extensive scarring and adhesions after midline division and suturing back of strap muscles [3]. The trans-axillary endoscopic and robotic thyroidectomy approaches also use the same lateral approach to reach and dissect the thyroid gland [5-9]. There have been a few publications studying the efficacy of the lateral approach and most authors conclude that a lateral approach offers excellent visualization of the vital structures [4].
Methods
We conducted a case control study comparing 90 patients undergoing conventional open
thyroidectomy from 1st January 2011 to 31st December 2012 after obtaining institutional review
board approval. The first 45 patients underwent ma and next 45 underwent la. Re-operative thyroid
surgery and minimally invasive endoscopic surgeries were excluded. basic demographic data, type
of surgery done in the 2 groups, operative time, incision length, complications, thyroid gland weight, the need to divide strap muscles and post-operative day 1 pain score
were recorded and compared between these 2 groups. The pain score
was measured using the visual analogue score (vas) on a scale of 0-10
by the ward nurses and recorded in the case sheets. Data was analyzed
using t-test and chi-square test.
Operative technique
In la technique, the same 4-6 cm skin crease neck incision
was used but instead of midline separation and retraction of strap
muscles. The anterior border of s cm was identified and mobilized
laterally. The superior belly of omohyoid that crosses the field was
retracted cranially. The lateral edge of strap muscles was identified
and retracted medially to expose the underlying goitre. The ansa
cervical is identified coursing downwards anterior to the sternohyoid
muscle and retracted medially with the sterno hypoid and sterno
thyroid muscles to expose the anterior surface of the thyroid lobe. The
plane between anterior surface of goitre and overlying strap muscles
was created as the strap muscles get pushed medially with retractors.
Next the carotid artery was identified and the a vascular plane postero
lateral to thyroid gland was opened to deliver the superior pole of
thyroid and allow it to be retracted downwards and outwards to free it
from larynx. The superior vascular pedicle could be easily identified in
this technique allowing individual ligation of vessels and preservation
of external laryngeal nerve. once the middle thyroid vein was
identified (if present) and ligated, the rest of thyroid lobe can be easily
dissected and retracted medially for easier identification of recurrent
laryngeal nerve and parathyroid glands. The inferior thyroid veins
were then ligated and divided and the thyroid lobe was freed from its
attachment to the ligament of berry and underlying trachea rings. For
hemi thyroidectomy, the isthmus was then transected to complete
the operation. For patients undergoing total thyroidectomy, similar
dissection of the opposite lobe was performed after identifying and
retracting the opposite scm. Once both the thyroid lobes were fully
dissected and freed from the overlying strap muscles, the smaller of
the lobes could be easily pushed beneath strap muscles to the opposite
site and the entire specimen was removed en-bloc for histology. At
the end of operation, the midline strap muscles cover over the trachea
remained intact preventing adherence of skin flap to the tracheal
cartilage. There was no need for closure or suturing of strap muscles
and the gap between lateral border of strap muscles and anterior
border of scm was always left open to prevent any life-threatening
hematoma from accumulating underneath the strap muscles. All total
thyroidectomy specimens were removed intact in the la group.
Table 1
Results
There was no significant difference in patient’s demographics, type of thyroid surgery in each group and thyroid gland weight (Table 1). The mean operative time for ma group (137 +/- 34.1 minutes) was slightly longer than la group (124 +/- 20.2 minutes) but not statistically significant. The mean incision length for both groups (4.9 +/- 1.1 cm vs. 5.2 +/ cm - 0.8 cm) showed no significant difference. 5 (11%) patients in ma group needed division of strap muscles to extract large goitres compared to only one patient (2.2%) in la group. postoperative day 1 pain scores were significantly lower in la group (0.82 +/- 0.72 vs 1.86 +/- 0.72; p = 0.02) compared to ma group (Table 1). no major complications occurred in either group such as significant post-operative haematoma or nerve injury causing voice change.
Discussion
The la technique (‘backdoor approach’) to thyroid surgery is
an established method for re-exploration of thyroid gland and
exploration of parathyroid lesions [2-4]. We believe this approach
allows easier access to the postero-lateral surface of the thyroid gland
where the critical structures such as parathyroid glands and the
nerves are located. It also allows easier delivery of large volume goitres
without the need for transecting the strap muscles horizontally.
This technique is routinely used in all transaxillary endoscopic and
robotic thyroidectomy [5-8]. There is no significant difference in
operative time or length of skin incision in this technique compare
to the traditional technique (ma) where midline division of the straps
muscles and resuturing after completion of surgery is employed. We
therefore feel it could be routinely used for all patients undergoing
conventional thyroid surgery for the first time.
A similar lateral, albeit endoscopic approach finds mention in the
technique described by henry and sabag in 2006 [9]. The principles of
approach to the thyroid lobe remains the same even when endoscopic
techniques are applied. Extensive experience with this approach in
endoscopic thyroidectomy has also been described by palazzo et al.
[10]. The proponents of endoscopic approach generally agree that
this approach is best suited for unilateral lesions and this “back
door” approach gives good exposure of the poster lateral aspect of
the thyroid gland without the need for dissecting and transecting
the strap muscles horizontally. In general, all alternate incision site thyroidectomy use this lateral approach purely or a combination of
lateral and midline approach as in the bilateral axillo-breast approach
(baba) technique except for the transoral endoscopic technique which
use the midline approach in view of anatomical ease of performance
[11]. A lateral approach of video assisted thyroidectomy has also been
described by ishikawa et al. [12] which uses this backdoor technique
compared to the traditional midline strap muscle separation
described by micoli et al. [13] in minimally invasive video-assisted
thyroidectomy (mivat).
In the past, due to the use of operations such as partial or subtotal
thyroidectomy, patients often had recurrent goitre on the same
side necessitating the use of la (‘backdoor technique’) to reach the
previously operated site and avoid the dense midline adhesions.
However, most established thyroid or head neck surgeons would
now perform a lobectomy or hemithyroidectomy for any unilateral
thyroid pathology that does not need a total thyroidectomy. Therefore,
the need to perform a revision thyroid surgery on the same side is
becoming less frequent as no remnant of the thyroid gland is usually
left behind. Hence the la is an ideal technique even for patients who
are undergoing unilateral or bilateral thyroid operation for the first
time. It does not increase the complexity of the surgery and most
surgeons performing thyroid operations are well versed with the
anatomy of neck muscles. Moreover the critical structures are more
easily identified. Even large bilateral goitres can be easily removed
intact by separating the anterior surface of goiter from overlying
strap muscles. This route of access to the lateral neck has also been
described recently for lymph node clearance in thyroid cancer. Yan et
al. [14] have described level ii, iii and IV clearance both during gasless
and gas insufflation techniques of minimal access thyroidectomy for
early cancers.
In our study, there is a lower incidence of strap muscles
transection for la group but it does not reach statistical significance
possibly due to a small number of patients. The strap muscles play an
important role in voice pitch control and swallowing function and
hence unnecessary midline division and suturing back of this muscle
as done in traditional ma can be avoided using la [15]. Kim in his study
mentionedthat handling of strap muscles and reconstitution or even
excessive retraction may affect voice quality and swallowing function
post-thyroidectomy [16]. The excessive retraction of strap muscles
laterally in main order to perform dissection postero-laterally along
the thyroid lobe could also be the possible reason for increased pain
score in these patients when delivering large glands. In our study,
post-operative pain score was significantly lower in the la group.
The transection of the strap muscles and their re-approximation is
associated with the greater post-operative pain and contributed to the
higher pain scores in the ma group. This is exactly the reason why we
advocate the la approach especially for larger goitres due to the ease
of approach to the superior pedicle and ability to retract and view
the critical poster lateral structures during thyroidectomy. The la
approach does reduce the incidence for transecting the strap muscles,
hence may inherently have lower pain scores.
Another significant advantage of la approach is the gap left
between anterior border of scm and lateral end of strap muscles after
resection of thyroid gland. This gap is always left open (on both sides
if a total thyroidectomy is performed) and acts as a safety valve in the
event patient has a significant post-operative bleeding. The blood can
easily flow through the gap superficially under the skin flap thereby
preventing significant trachea compression, laryngeal edema and
stridor. In the ma approach, the midline re-approximation of the strap
muscles and the lack of space between the sternomastoid and lateral
edge of the strap muscles may allow a life-threatening hematoma
beneath the strap muscles should there be a significant post-operative
bleed. The authors acknowledge one of the limitations of this study is
that it is a case control comparative study. A randomised control trial
between the ma and la group would have provided stronger evidence.
In conclusion, this study shows that the la (‘backdoor’) technique is
as safe as conventional ma even for initial thyroid surgery. It reduces
the need to transect the strap muscles horizontally for delivery of
large goitres and has significantly lower pain scores compared to
the traditional midline approach. It is now the authors’ technique of
choice for all conventional open thyroid surgery.
References
- Giddings AE. The history of thyroidectomy. J R Soc Med. 1998;91 Suppl 33:3-6.
- Alaa ME, Amr AE, Jhab H, Morad E. Lateral Approach to Attack Superior Thyroid Vascular Pedicle Eliminates the Need for Strap Muscles Cutting during Thyroidectomy. Med J Cairo Univ. 2015;83(2):125-34.
- Dissanayake DDMC, Fernando RF, Dissanayake IJ. Lateral Approach to Thyroid: A Good Technique for Reoperative Thyroid Surgery. World Journal of Endocrine Surgery. 2016;8(2):141-2.
- Oertli. Surgery of the Thyroid and Parathyroid Glands. Springer. 2012.
- FF Palazzo. Endocrine surgical technique: endoscopic thyroidectomy via the lateral approach. Surg Endosc. 2006;20(2):339-42.
- Sebag F, Palazzo FF, Harding J, Sierra M, Ippolito G, Henry JF. Endoscopic lateral approach thyroid lobectomy: safe evolution from endoscopic parathyroidectomy. World J Surg. 2006;30(5):802-5.
- Giannopoulos G, Kang SW, Jeong JJ, Nam KH, Chung WY. Robotic thyroidectomy for benign thyroid diseases: a stepwise strategy to the adoption of roboticthyroidectomy (gasless, transaxillary approach).Surg Laparosc Endosc Percutan Tech. 2013;23(3):312-5.
- Kiriakopoulos A, Linos D. Gasless transaxillary robotic versus endoscopic thyroidectomy: exploring the frontiers of scarless thyroidectomy through a preliminary comparison study. Surg Endosc. 2012;26(10):2797-801.
- Henry JF, Sebag F. [Lateral endoscopic approach for thyroid and parathyroid surgery]. Ann Chir. 2006;131(1):51-6.
- Palazzo FF, Sebag F, Henry JF. Endocrine surgical technique: endoscopic thyroidectomy via the lateral approach. Surg Endosc. 2006;20(2):339-42.
- Mohamed SE1, Noureldine SI, Kandil E. Alternate incision-site thyroidectomy. Curr Opin Oncol. 2014;26(1):22-30.
- Ishikawa N, Kawaguchi M, Matsunoki A, Shimizu S, Watanabe G. Video-assisted neck surgery for thyroid tumor: gasless lateral approach. Asian J Endosc Surg. 2011;4(3):153-5.
- Miccoli P, Berti P, Raffaelli M, Conte M, Materazzi G, Galleri D. Minimally invasive video-assisted thyroidectomy. Am J Surg. 2001;181(6):567-70.
- Yan H, Wang Y, Wang P, Xie Q, Zhao Q. "Scarless" (in the neck) endoscopic thyroidectomy (SET) with ipsilateral levels II, III, and IV dissection via breast approach for papillary thyroid carcinoma: a preliminary report. Surg Endosc. 2015;29(8):2158-63.
- Hong KH, Ye M, Kim YM, Kevorkian KF, Berke GS. The role of strap muscles in phonation--in vivo canine laryngeal model. J Voice. 1997;11(1):23-32.
- Kim YM, Cho JI, Kim CH, Park JS, Choi HS, Ha HR. Voice comparison between strap muscle retraction and cutting technique in thyroidectomy. Korean J Otolaryngol-Head Neck Surg. 2000;43(9):985-91.