SHOULDER

Arthroscopic suprascapular nerve decompressionat the suprascapular notch

Sung-Hun Kim Æ Sung-Jae Kim Æ Chang-Hun Sung ÆYong-Gon Koh Æ Yong-Chan Kim Æ Young-Sik Park

Received: 1 February 2009 / Accepted: 16 June 2009 / Published online: 11 July 2009

� Springer-Verlag 2009

Abstract Release of a transverse scapular ligament

(TSL) is indicated for the entrapment of the suprascapular

nerve (SSN). Previous arthroscopic techniques use step-

wise reference landmarks leading to the notch to identify a

TSL, and the key landmarks are the conoid ligament of the

coracoclavicular ligament and the coracoid. This technique

needs considerable amount of fibro-fatty tissue removal,

which is time-consuming procedure. The technique

described herein uses the superior border of scapula as a

key landmark. A lateral portal is used as a viewing portal,

and an anterolateral portal, SSN portal, and accessory

portal are required for the working portals. To identify the

superior border of the scapula, dissection proceeds along

the anterior border of the supraspinatus and advances

medially into the supraspinatus fossa. Then, the TSL could

be identified by palpating laterally along the superior

border of scapula as a dimpling portion.

Keywords Suprascapular nerve �Transverse scapular ligament � Superior border of scapula �Suprascapular notch � Shoulder arthroscopy

Introduction

The suprascapular nerve (SSN) may be injured by direct

trauma, repetitive over-use, space-occupying lesions, or

traction injury because the nerve is relatively fixed where

it passes through the suprascapular notch [7]. SSN

entrapment at the suprascapular notch could produce pain,

especially posterior shoulder pain, which is characterized

as a dull ache, and is exacerbated by overhead activities.

Other common clinical findings are hypotrophy of the

scapular muscles, tenderness at the triangle between the

clavicle and scapular spine, and weakness of abduction

and external rotation. Severely retracted rotator cuff tears

may cause nerve palsy because of a pulling effect beneath

the transverse scapular ligament (TSL) [8]. Electrophysi-

ological studies are mandatory for the confirmation of

SSN entrapment at the suprascapular notch. Magnetic

resonance imaging is also necessary to rule out the more

common cause of ganglion cysts at the suprascapular

notch. Release of the TSL is indicated in patients with

proven SSN entrapment refractory to non-operative

treatment [5].

There are several reports of arthroscopic suprascapular

nerve release [1–3, 6]. These methods use the conoid lig-

ament of the coracoclavicular ligament and coracoid as a

guide to identify the TSL. These methods require consid-

erable amount of fibro-fatty tissues removal in order to

approach these structures, which is a time-consuming

procedure. Also, the removal procedure may cause damage

to the suprascapular nerve or vessel.

Electronic supplementary material The online version of thisarticle (doi:10.1007/s00167-009-0858-1) contains supplementarymaterial, which is available to authorized users.

S.-H. Kim � C.-H. Sung � Y.-G. Koh � Y.-C. Kim � Y.-S. Park

Department of Orthopaedic Surgery, Yonsei Sarang Hospital,

Seoul, Korea

S.-J. Kim (&)

Department of Orthopaedic Surgery, Arthroscopy and Joint

Research Institute, Yonsei University College of Medicine,

C.P.O. Box 8044, 134 Shinchon-dong, Seodaemun-gu,

Seoul 120-752, Korea

e-mail: sungjaekim@yuhs.ac; severanscopy@yumc.yonsei.ac.kr;

sungjaekim@yumc.yonsei.ac.kr

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DOI 10.1007/s00167-009-0858-1

The purpose of our report is to describe a new technique

for the decompression of the SSN in which the superior

border of the scapula is used as a guide.

Surgical technique

The patient is placed in either a lateral decubitus or beach-

chair position under general anesthesia. We used epi-

nephrine-mixed saline (0.33 mg/L) and a pump pressure of

about 60 mmHg, and a systolic blood pressure is main-

tained less than 120 mmHg. The necessary portals and

position of instruments are described schematically

(Fig. 1).

An arthroscope is inserted into the lateral portal. A per-

tinent bursectomy is performed with a shaver through the

posterior portal for the clear visualization. At a point 3 cm

anterior to the lateral portal, a spinal needle is inserted

along the anterior border of the supraspinatus (Fig. 2a).

After confirming the parallel direction of the spinal needle

with the supraspinatus, an anterolateral portal is made.

A shaver is inserted into the anterolateral portal, and all of

the anteromedial bursal tissue is cleared off along an

anterior border of the supraspinatus.

To approach the supraspinatus fossa further medially,

blunt dissection is made with a blunt trocar just above the

anterior border of the supraspinatus (Fig. 2b). Obscuring

fibro-fatty tissues could be removed if necessary. A path-

way of the trocar through the anterolateral portal is boun-

ded by the coracoacromial and coracoclavicular ligaments

anteriorly, the coracoid process anteroinferiorly, the acro-

mioclavicular joint and trapezius superiorly, and the

supraspinatus muscle posteroinferiorly. The inserted trocar

was backed out and the arthroscope is advanced medially

into the supraspinatus fossa, which is in the same direction

as the trocar. If the arthroscope is advanced medially about

7 cm from the lateral border of the acromion, the tip of the

arthroscope is located at a space above a muscular portion

of supraspinatus and under trapezius muscle. This space is

medial to both the suprascapular notch and fatty tissues

surrounding suprascapular neurovascular pedicle. The

space is above the superior border of the scapula, which is

covered by the supraspinatus muscle. At this point, the

inserted length of an arthroscope is about 9–10 cm from

the lateral portal.

The next step is making a SSN portal, which was

described by Lafosse et al. [6]. The portal is located

between the clavicle and the scapular spine approximately

7 cm medial to the lateral border of the acromion, and

approximately 2 cm medial to the Neviaser portal. An

18-gauge spinal needle is inserted vertically at this point

through the trapezius in a slightly anterior direction. If the

position of the spinal needle is correct, then the tip of

the spinal needle should be directly visualized under the

arthroscope and located anterior to the anterior border of

the supraspinatus muscle. Then, the SSN portal is made.

Fig. 1 Schematic representation of the position of instruments and

necessary portals. The arthroscope is inserted through the lateral

portal (L) and the blunt trocar through the anterolateral portal (AL).

The supraspinatus muscle is retracted posteriorly with blunt trocar via

the SSN portal and TSL is identified with careful palpation using the

probe via the accessory portal (AC) (right shoulder)

Fig. 2 a The tip of the spinal needle is positioned just above the

anterior border of the supraspinatus tendon (asterisk). b The blunt

trocar is inserted into supraspinatus fossa along the superior border of

supraspinatus and blunt dissection is performed toward the supras-

pinatus fossa (right shoulder)

Knee Surg Sports Traumatol Arthrosc (2009) 17:1504–1507 1505

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Through this portal, additional shaving or blunt dissection

of fibro-fatty tissues can be done, if necessary. One must be

careful not to damage the suprascapular artery located

within the fibro-fatty tissues.

When a clear vision is obtained, a blunt trocar is inserted

through the SSN portal. The overlying supraspinatus

muscle is retracted posteriorly and a careful palpation of

the superior border of the scapula is performed (Fig. 3a).

Next, an accessory SSN portal is made 2 cm lateral to the

SSN portal. The supraspinatus muscle is retracted posteri-

orly with a blunt trocar via the SSN portal, and a hooked

probe is inserted from the accessory portal. Palpation along

the superior border of the scapula laterally towards the TSL

can identify a dimpling portion, which is the suprascapular

notch (Fig. 3b). At this time, resistance due to bone dis-

appears suddenly when the hooked probe approaches the

suprascapular notch. Soft tissues around the TSL are

pushed aside with a blunt trocar or the probe, and the TSL

is more clearly identified. The TSL is angulated a little

forward compared to superior border of scapula. And then

an arthroscopic scissors are inserted through the accessory

portal. The TSL is cut with the scissors. To ensure

complete release of the TSL, the SSN is mobilized outside

the suprascapular notch with the probe, and the skin is

closed.

Discussion

Arthroscopic release of TSL is a technically demanding

procedure to decompress the SSN at the suprascapular

notch. Our study is to describe a novel method to release

SSN at the suprascapular notch in the case of a proven SSN

entrapment.

The mechanism of suprascapular nerve injury at the

suprascapular notch has been termed the sling effect by

Rengachary et al. [7]. Various predisposing factors, such as

repetitive or extreme shoulder motions, morphologic

changes of the notch, and various anatomical changes have

been considered as possible causes. Surgical release of TSL

is warranted for SSN entrapment at the suprascapular notch

when non-operative treatment fails. Studies with anatomic

dissection suggest that the suprascapular nerve can be

injured from traction injury during cuff tendon lateral

mobilization than previously thought [8]. Release of the

TSL could increase mobilization of the SSN [4, 8].

Arthroscopic TSL release has been described previously

by some authors [1–3, 6]. The reported methods use step-

wise reference landmarks leading medially to the notch.

The difference between previously reported methods and

our method is the direction of dissection to approach the

suprascapular notch. In the method of Lafosse et al. [6],

first, the coracoacromial ligament is identified, and fol-

lowed to the base of the coracoid. Then, the coracocla-

vicular ligaments are identified. Finally, the TSL is

identified as the medial continuity of the conoid ligament

above the suprascapular notch. In the method of Bhatia

et al. [3], the acromioclavicular joint is first marked with a

needle. Then, the coracoclavicular ligament 15 mm medial

to the acromioclavicular joint is identified. Next, its

attachment on the coracoid is followed inferiorly, and then

the suprascapular notch is identified medial to the coracoid

process, with the conoid ligament often continuing as the

TSL.

In our method, the dissection is carried out along the

anterior border of the supraspinatus and advanced medially

into the supraspinatus fossa for identification of the supe-

rior border of the scapula. Next, the suprascapular notch is

identified by palpation laterally along the superior border

of the scapula as a dimpling portion. For the approach into

supraspinatus fossa, usually blunt dissection is sufficient.

But in some cases, a little removal of fatty tissues may be

needed to dissect medially, but the amount is less than

other operative techniques which need approach to the

coracoclavicular ligament and base of coracoid. In order to

Fig. 3 a The arthroscope is advanced medially into the supraspinatus

fossa, a space above a muscular portion of supraspinatus. By

retracting the supraspinatus muscle posteriorly with a blunt trocar

via the SSN portal, the superior border of the scapula (asterisk) is

identified. b A careful palpation along the superior border of the

scapula laterally can identify the suprascapular notch as a dimpling

(right shoulder)

1506 Knee Surg Sports Traumatol Arthrosc (2009) 17:1504–1507

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expose the superior border of scapular, overlying supra-

spinatus muscle should be retracted posteriorly. In the case

of a massive cuff tear combined with SSN entrapment, its

exposure is easier due to atrophy and little volume of the

supraspinatus muscle. Since the suprascapular artery

always course lateral to the nerve, cutting the medial por-

tion of TSL after lateral retraction of fatty tissues is safer

than cutting the lateral side. Furthermore, the operation

time is less than 10 min and there is no need for a 70�angled scope.

This study has some limitations including lack of clin-

ical outcomes of this procedure, absence of a comparative

study with other methods. But this technique could be one

of the alternatives for TSL release in the case of SSN

entrapment.

Conflict of interest statement The authors report no conflicts of

interest.

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