Trial Information

Shoulder Function After Level IIB Neck Dissection: A Randomized Controlled

The lymphatic fluid of upper aerodigestive tract (UADT) drains into various levels of the
neck. When cancer occurs in the UADT, the potential for local metastatic spread to the neck
exists, thus necessitating treatment of the neck. Ideally all potential neck structures,
which could harbor cancer cells or provide a dock for recurrence, would be eradicated.
Unfortunately, such radical treatments have shown to cause extreme rates of morbidity with
little extra oncologic benefit. Thus, head and neck oncologists have strived to create
treatment paradigms, which maximize cure rates while minimizing morbidity. Finding this
intricate balance has translated to selective neck dissection (SND) and post-operative RT.1

Increased understanding of lymphatic drainage patterns in the head and neck has lead to
widespread use of SND. Through removal of lymphatics in neck levels with the highest risk of
harboring cancer cells, based on primary tumor site, important neck structures may be
preserved. As such, the treatment remains oncologically sound and avoids the morbidity
associated with its predecessor, the radical neck dissection. 1

One of the structures preserved in the SND is the spinal accessory nerve (SAN), which is
responsible for providing motor innervation to the sternocleidomastoid (SCM) and trapezius
muscles. Thus, it is intricately involved in shoulder function. The nerve exists the skull
base at the jugular foramen and obliquely passes through neck level II. It then passes
posterior to the SCM and eventually enters the trapezius muscles. Through this trajectory,
it divides level II into IIa (anterior to the SAN) and IIb (posterior to the SAN).

It is known that shoulder function significantly deteriorates when level V is dissected.2
This is likely due to traction and devascularization injury of the longest portion of the
SAN in the neck. As such, practice has become such that level V is left intact in cases
where it does not harbor detectable disease or when occult disease incidence is very low.
Due to the intimate relationship of IIb with the SAN, there is also potential for injury to
the nerve in this area.2 As such, debate has arisen to the necessity of including IIb in the
neck dissection specimen. Studies have shown that the prevalence of occult nodal disease in
IIb ranges from 0-8.7.5% depending on the overall n stage of the neck.3-5 These figures have
lead head and neck surgeons to weigh the benefits of not excising lymphatic tissue with low
nodal metastatic rates versus excising the area and decreasing post-operative shoulder
function.6

Because the incidence of occult metastases in IIb is low3-5, it has become standard of care
in many centers to spare IIb, if it is oncologically feasible, in SND to preserve shoulder
function. Because these patients receive post-operative RT it is thought that the RT will
address any occult disease. Unfortunately, relying on RT poses two problems:

1. occult disease may not respond to the RT

2. leaving level IIb intact provides a lymphatic route of recurrence despite undergoing RT
By surgically removing all portals of lymphatic disease spread these issues above can
be eliminated.

The goal of this study is to demonstrate that the minimal manipulation of the SAN associated
with IIb dissection will not have a significant impact on post-operative shoulder function.
If this is the case, the standard of practice should be changed to include IIb in the SND
specimen in cases where level IIa is dissected as well. This would eliminate any further
lymphatic tissue, which may harbor disease.

Note: At the University of Alberta, some head and neck surgeons prefer to spare IIb in SND,
while others prefer to resect it. Thus, the protocol in this study does not manipulate
current standards of practice.

*Reference numbers correspond to articles in the "Citations" section. The citations are in
order of appearance in the above text.