Superomedial Portal (Ejnisman's Portal) and Modified "Chicken-Wing" Patient Position for Scapulothoracic Arthroscopy.

Scapulothoracic arthroscopy is performed to treat scapulothoracic joint disorders, such as scapulothoracic bursitis, snapping scapula, and osteochondroma of the anterior scapula surface, and in the extraction of firearm projectiles. This article describes this treatment using an alternative superomedial portal and modified chicken-wing position to improve access to the scapulothoracic space and thus perform the procedure as safely as possible, with less morbidity and excellent results for the patients.

Scapulothoracic joint disorders may be characterized according to their etiology., The presence of mechanical symptoms may denote a bony protrusion or abnormal morphology of the joint soft tissue or can also be caused by a foreign body. These structural abnormalities frequently result in inflammation, bursitis, and scapular crepitus. In cases without mechanical symptoms, pain is related to the occurrence of overload syndrome, resulting in symptomatic bursitis. The latter phenomenon characteristically occurs in young, active patients and athletes who throw.

Scapulothoracic joint arthroscopy was first described by Ciullo and Jones (1,992) and has been continuously improved over time.5, 6, 7, 8 Although its indications are restricted, including snapping scapula syndrome, decompression for scapulothoracic bursitis, foreign body resection, benign tumor resection, and treatment of chronic pain refractory to conservative treatment,5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22 arthroscopy is associated with lower morbidity, better esthetic results, and faster rehabilitation.

The arthroscopic scapulothoracic anatomy was described in cadaveric studies performed by Ruland et al., who listed the relevant neurovascular structures and suggested safe portals to avoid injuring noble structures. The scapulothoracic joint includes 2 triangular spaces, the serratus anterior space, and the subscapularis space, which are divided obliquely by the serratus anterior muscle. The boundaries of the anterior serratus space include the anterior serratus muscle posteriorly, the rhomboid muscle medially, and the chest wall anteriorly. The subscapularis space is bounded by the anterior serratus muscle, the subscapularis muscle posteriorly, and the axilla laterally.

In an anatomic study conducted with cadavers, Andreoli et al. showed that arthroscopy becomes safer through modification of the classic patient positioning, which further allows for safe use of the superomedial portal. The aim of the present study was to describe the surgical technique for scapulothoracic arthroscopy using a modified chicken-wing position and 2 medial portals only, including the superomedial portal, i.e. Ejnisman's portal.

Clinical Findings

Although diagnosis is mainly clinical, radiographs are taken. An example of Luschka's tubercle, characterized by a hooked superomedial angle of the scapula as evidenced by computed tomography, while magnetic resonance imaging detected local inflammation, is shown in Figure 1.

Fig 1

Magnetic resonance imaging of a left scapula on T2 demonstrating the inflammatory process in the superomedial angle of the scapula (red arrow).

Surgical Technique

The surgical procedure is begun by placing the patient on ventral decubitus with the affected limb in maximum internal rotation (chicken-wing position), which is modified by placing a pad underneath the scapula (pad anterior to the affected scapula) and with lateral support of the shoulder in the medial direction, with consequent posteriorization of the scapula, as described by Andreoli et al. This modification of the chicken-wing position using a pad anterior to the shoulder allows placement of the scapula perpendicular to the chest plane and increases the space between the rib cage and scapula (Fig 2A and B).

Fig 2

(A-B) Ventral decubitus with the affected left limb in maximum internal rotation (chicken-wing position) using a pad anterior to the shoulder (red arrow) with posteriorization of the scapula.

Portals

The portals are marked 2 cm lateral to the medial border of the scapula:

Portal 1: Ejnisman's portal—at the level of the superomedial angle of the scapula

Portal 2: at the level of the scapular spine

Portal 3: between the scapular spine and the inferior angle of the scapula; and

Portal 4: Bell's portal—between the upper two-thirds of the scapular spine.

An infusion pump at 40-mm Hg pressure was used in all cases and using a 30° arthroscope (Karl Storz, Tuttlingen, Germany). A summary of the pearls and pitfalls, advantages, and disadvantages is listed in Tables 1 and 2.

Table 1

Pearls and Pitfalls

Pearls	Pitfalls
Place the patient in the chicken-wing position, which is modified by placing a pad underneath the scapula (pad anterior to the affected scapula) with consequent posteriorization of the scapula.	Be careful of a thin scapula; do not dry more than 2 cm.
Two portals only are marked 2 cm lateral to the medial border of the scapula: Ejnisman's portal—at the level of the superomedial angle of the scapula—and the portal at the level of the scapular spin.	The ideal surgery time is approximately 30-50 min, which minimizes the possibility of adverse events and complications.

Table 2

Advantages and Disadvantages

Advantages	Disadvantages
• Lower morbidity	• Learning curve
• Lower postoperative pain	• Control of vascular injury

Bursectomy (With Video Illustration)

The use of a portal at the level of the superomedial angle of the scapula provides direct access for bursectomy and resection of the superomedial angle of the scapula of up to 2 cm, thus avoiding the need for levator scapulae muscle disinsertion.

The described patient position and Ejnisman's portal were used (Fig 3). All cases were performed the bursectomy and resection the superomedial angle of scapula (Fig 4, Video 1).

Fig 3

Scapulothoracic arthroscopy in the left with 2 portals (red arrows) from snapping scapula. (A) Ejnisman's portal—scapular superomedial portal. (B) Portal at the level of the scapular spine.

Fig 4

Superomedial arthroscopic images. (A) Bursectomy with full radius. (B) Resection of the scapula with an acromionizer.

Discussion

Scapulothoracic arthroscopy has precise indications, such as snapping scapula,,,,,24, 25, 26 resection of foreign bodies or benign tumors,19, 20, 21, fracture malunion, and chronic pain refractory to conservative treatment. Intra-articular extraction of firearm projectile fragments has been described for the knee, elbow, hip, and subtalar joints.29, 30, 31, 32, 33, 34 In 2003, Proctor and Stanert described the same procedure for the scapulothoracic joint.

Arthroscopic intervention has been increasingly reported in the literature since its first description by Ciullo. Ruland et al. described safe portals in their 1,995 study of the anatomy of the scapulothoracic region; new portals for arthroscopy have been described since that time.,,,

The following anatomical landmarks for portals,,,, were used in our procedure: 2 cm medial to the superior angle of the scapula; 2 cm medial to the scapular spine; midpoint between the spine and the inferior pole of the scapula, 2 cm medial to the medial border of the scapula; and the inferior angle of the scapula. The portals are made 2 to 3 cm medially to the medial border of the scapula and inferiorly to the spine of the scapula to reduce the risk of injuring the main neurovascular bundles.

Andreoli et al. tested the “chicken-wing” position combined with placement of a pad underneath the shoulder in 20 cadavers and observed an increase in the space between the scapula and the chest wall., This space may be further enlarged through medial compression of the lateral shoulder, thereby causing additional bayonet apposition of the body of the scapula. We believe that modified position is safer, as it increases the mean distance to the spinal accessory nerve, which is intimately related to the scapulothoracic bursa wall, from the usual 2.4 cm with the typical position to 3.2 cm (Fig 5).

Fig 5

(A-B) Image of the 2 portals (red arrows) after surgery in the left scapula.

In the aforementioned anatomical study with cadavers, Andreoli et al. safely used the superomedial portal, which is the same portal we used in our case series, thus demonstrating its reliable reproducibility. This portal is named Ejnisman's portal.

According to the literature, the ideal duration of surgery is 30 minutes, and to avoid the occurrence of complications, the procedure should not last longer than 50 minutes, as reported by Andreoli et al. Those authors defined edema as a parameter for complications and categorized edema as follows: mild as localized swelling of the scapular region, however, allowing for visualization of the scapula contours; moderate as loss of the scapula contours; and severe as loss of the scapula contours and swelling extends to other regions such as the neck, inferior dorsal region, and contralateral side of the thoracic spine.

Millett et al. were not able to find any report of complications in the literature; nonetheless, arthroscopic techniques require additional training, and they emphasize that the technique is still under development. It is necessary to avoid the risk of neurovascular injury. In the present study by Andreoli et al. no case of neurovascular injury or thoracic penetration occurred.

Ejnisman's (superomedial) portal can be safely used, especially when the modified “chicken-wing” position is adopted, provided that the surgeon has mastery of the anatomy of the region targeted in the surgical procedure, as well as the surgical technique.