Abstract

2b or Not 2b? Shoulder Function After Level 2b Neck Dissection: A Double-Blind Randomized Controlled Clinical Trial

Peter T. Dziegielewski, MD 1,2,3; Margaret L. McNeely, PhD4; Nigel Ashworth, MBChB5; Daniel A. O’Connell, MD3;  Brittany Barber, MD3; Kerry S. Courneya, PhD 6; Brock J. Debenham, MD7; and Hadi Seikaly, MD3. Cancer 2019

BACKGROUND: Selective neck dissection (SND) is a mainstay of head and neck cancer treatment. A common sequela is shoulder syndrome from spinal accessory nerve (SAN) trauma. Extensive dissection in neck levels 2 and 5 leads to SAN dysfunction. However, it is not known whether limited level 2 dissection reduces SAN injury. The purpose of this double-blind randomized controlled trial was to determine whether omitting level 2b dissection would improve shoulder-related quality of life and function.

METHODS: Patients with head and neck cancers undergoing surgery were randomized 1:1 to SND without level 2b dissection (group 1) or with it (group 2) on their dominant-hand side. Patients, caregivers, and assessors were blinded. The primary outcome was the change in the Neck Dissection Impairment Index (NDII) score after 6 months. An a priori calculation of the minimally important clinical difference in the NDII score was determined to establish a sample size of 15 patients per group (power = 0.8). Secondary outcomes included shoulder strength and range of motion (ROM) and SAN nerve conduction. The trial was registered at ClinicalTrials.gov (NCT00765791).

RESULTS: Forty patients were enrolled, and 30 were included (15 per group). Six months after the surgery, group 2 demonstrated a significant median decrease in the NDII from the baseline (30 points) and in comparison with group 1, whose NDII dropped 17.5 points (P = .02). Shoulder ROM and SAN conduction demonstrated significant declines in group 2 (P ≤ .05). No adverse events occurred.

CONCLUSIONS: Level 2b should be omitted in SND when this is oncologically safe and feasible. This allows for an optimal balance between function and cancer cure.  Cancer 2019;0:1-10. © 2019 American Cancer Society.

Main findings

• Selective neck dissections (SNDs) are routinely practiced because they reduce morbidity while maintaining oncologic efficacy.
• The most common long-term complication of neck dissection is shoulder dysfunction due to the dissection of, or injury to, the spinal accessory nerve (SAN).3 The result is shoulder syndrome, which includes chronic pain, weakness, limited range of motion (ROM), shoulder droop, and impaired shoulder-related quality of life (QOL).
• SND can be modified to preserve level 2b, and this may lessen shoulder morbidity.8-11 Level 2b is often dissected in node-positive (N1-N3) necks12; in node-negative (N0) necks, this is surgeon- dependent.
• N=40
• This study convincingly shows that SND (2a-4) causes less shoulder impairment than SND including 2b. Shoulder-related QOL at 6 months postoperatively was 17 points lower than the baseline with 2b-sparing dissection (group 1). This drop is statistically but not clinically significant. For patients with level 2b dissected (group 2), the decline was 30 points at 6 months, which is statistically and clinically significant.
• All active ROM measures declined in both groups from the baseline to 6 months. Although most patients showed a partial recovery, no patient experienced a full recovery.
• most significant ROM disruption is in abduction when both level 515,16 and level 2b are dissected.
• Patients with level 2b dissected lost a median of 61 degrees in abduction, which was significantly worse than that for their counterparts at 6 months (P = .049).
• Passive ROM was not significantly affected by level 2b dissection, and this suggests that the loss of active ROM was not due to mechanical contractures in the shoulder joint. Rather, the loss of motion was linked to losses in nerve function.
• Both groups maintained shoulder strength, endurance, and shoulder height. This is likely attributable to the development of compensatory musculature in the shoulder girdle.
• Patients, especially those undergoing 2b dissection, may benefit from ongoing PT and follow-up beyond 6 months. Future studies could consider follow- up of 1 year or longer because shoulder-related QOL and functional measures may continue to improve over time. This would be especially true for patients committed to ongoing long-term shoulder rehabilitation.
• In conclusion, SND including level 2b leads to significant long-term deterioration in QOL and active abduction and nerve conduction amplitude deficiencies. When it is oncologically sound, level 2b should be omitted from SND.