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Identification of three anatomical patterns of the spinal accessory nerve in the neck by neurophysiological mapping.

Lanisnik B, Zargi M, Rodi Z - Radiol Oncol (2014)

Bottom Line: In type 2 the nerve for trapezius muscle branches off before entering the SCm (22%).The nerve than exits this junction more medially as a single trapezius branch.The description of three anatomical patterns in level II and V could help preserving the trapezius branch during MRND.

View Article: PubMed Central - PubMed

Affiliation: Department of Otorhinolaryngology, Cervical and Maxillofacial Surgery, University Medical Center Maribor, Slovenia.

ABSTRACT

Background: In spite of preservation of the accessory nerve there is still considerable proportion of patients with partial nerve damage during modified radical neck dissection (MRND).

Methods: The nerve was identified during the surgery and its branches for the trapezius muscle mapped with nerve monitor.

Results: The accessory nerve was mapped during 74 hemineck dissections and three patterns were identified. In type 1 nerve exits at the posterior end of the sternocleidomastoid muscle (SCm) and then it enters the level V (66%). In type 2 the nerve for trapezius muscle branches off before entering the SCm (22%). In type 3 the nerve exits at the posterior part of the SCm and it joins to the cervical plexus (12%). The nerve than exits this junction more medially as a single trapezius branch.

Conclusions: The description of three anatomical patterns in level II and V could help preserving the trapezius branch during MRND.

No MeSH data available.


Related in: MedlinePlus

Placement of the electrodes in the patient before surgery. Surface electrodes over the trapezius are seen as well as needle electrodes in the trapezius and deltoid muscles. Reference and ground electrodes are placed over the jugulum.
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f1-rado-48-04-387: Placement of the electrodes in the patient before surgery. Surface electrodes over the trapezius are seen as well as needle electrodes in the trapezius and deltoid muscles. Reference and ground electrodes are placed over the jugulum.

Mentions: The mapping of the accessory nerve was performed using an intraoperative nerve monitoring device NIM 2.0 (Medtronic Navigation Inc., USA) with bipolar needle and surface electrodes placed in/over the trapezius muscle (registering electrode over the biggest muscle mass and negative electrode over the acromion, Figure 1). A needle electrode was also placed in the deltoid muscle to detect a possible contamination from the stimulation of the brachial plexusSurface electrodes record compound muscle action potentials (CMAP) from a much wider area compared to needle electrodes thus giving better estimation of the number of excitable motor axons innervating the given muscle. On the other hand, bifocally placed needle electrodes record the CMAP only between the needle tips in a localized area of the muscle thus minimizing the risk of recording the action potential from surrounding muscles but at the same time detecting only the smaller fraction of motor axons. Only stimulations with responses recorded on both needle and surface electrodes placed in/over trapezius muscle, and at the same time showing no response in deltoid muscle, were considered to originate from the accessory nerve or its branches.


Identification of three anatomical patterns of the spinal accessory nerve in the neck by neurophysiological mapping.

Lanisnik B, Zargi M, Rodi Z - Radiol Oncol (2014)

Placement of the electrodes in the patient before surgery. Surface electrodes over the trapezius are seen as well as needle electrodes in the trapezius and deltoid muscles. Reference and ground electrodes are placed over the jugulum.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4230559&req=5

f1-rado-48-04-387: Placement of the electrodes in the patient before surgery. Surface electrodes over the trapezius are seen as well as needle electrodes in the trapezius and deltoid muscles. Reference and ground electrodes are placed over the jugulum.
Mentions: The mapping of the accessory nerve was performed using an intraoperative nerve monitoring device NIM 2.0 (Medtronic Navigation Inc., USA) with bipolar needle and surface electrodes placed in/over the trapezius muscle (registering electrode over the biggest muscle mass and negative electrode over the acromion, Figure 1). A needle electrode was also placed in the deltoid muscle to detect a possible contamination from the stimulation of the brachial plexusSurface electrodes record compound muscle action potentials (CMAP) from a much wider area compared to needle electrodes thus giving better estimation of the number of excitable motor axons innervating the given muscle. On the other hand, bifocally placed needle electrodes record the CMAP only between the needle tips in a localized area of the muscle thus minimizing the risk of recording the action potential from surrounding muscles but at the same time detecting only the smaller fraction of motor axons. Only stimulations with responses recorded on both needle and surface electrodes placed in/over trapezius muscle, and at the same time showing no response in deltoid muscle, were considered to originate from the accessory nerve or its branches.

Bottom Line: In type 2 the nerve for trapezius muscle branches off before entering the SCm (22%).The nerve than exits this junction more medially as a single trapezius branch.The description of three anatomical patterns in level II and V could help preserving the trapezius branch during MRND.

View Article: PubMed Central - PubMed

Affiliation: Department of Otorhinolaryngology, Cervical and Maxillofacial Surgery, University Medical Center Maribor, Slovenia.

ABSTRACT

Background: In spite of preservation of the accessory nerve there is still considerable proportion of patients with partial nerve damage during modified radical neck dissection (MRND).

Methods: The nerve was identified during the surgery and its branches for the trapezius muscle mapped with nerve monitor.

Results: The accessory nerve was mapped during 74 hemineck dissections and three patterns were identified. In type 1 nerve exits at the posterior end of the sternocleidomastoid muscle (SCm) and then it enters the level V (66%). In type 2 the nerve for trapezius muscle branches off before entering the SCm (22%). In type 3 the nerve exits at the posterior part of the SCm and it joins to the cervical plexus (12%). The nerve than exits this junction more medially as a single trapezius branch.

Conclusions: The description of three anatomical patterns in level II and V could help preserving the trapezius branch during MRND.

No MeSH data available.


Related in: MedlinePlus