Original portals for arthroscopic decompression of the suprascapular nerve: an anatomic study

Decompression of the suprascapular nerve at the suprascapular notch under combined arthroscopic and ultrasound guidance

Decompression of the suprascapular nerve (SSNe) at the suprascapular notch (SSNo) is usually performed with an arthroscopic procedure. This technique is well described but locating the nerve is complex because it is deeply buried and surrounded by soft tissue. We propose to combine ultrasound and arthroscopy (US-arthroscopy) to facilitate nerve localization, exposure and release. The main objective of this study was to assess the feasibility of this technique. This is an experimental, cadaveric study, carried out on ten shoulders. The first step of our technique is to locate the SSNo using an ultrasound scanner. Then an arthroscope is introduced under ultrasound control to the SSNo. A second portal is then created to dissect the pedicle and perform the ligament release. Ultrasound identification of the SSNo, endoscopic dissection and decompression of the nerve were achieved in 100% of cases. Ultrasound identification of the SSNo took an average of 3 min (± 4) while dissection and endoscopic release time took an average of 8 min (± 5). Ultrasound is an extremely powerful tool for non-invasive localization of nerves through soft tissues, but it is limited by the fact that tissue visualization is limited to the ultrasound slice plane, which is two-dimensional. On the other hand, arthroscopy (extra-articular) allows three-dimensional control of the surgical steps performed, but the locating of the nerve involves significant tissue detachment and a risk of damaging the nerve with the dissection. The combination of the two (US-arthroscopy) offers the possibility of combining the advantages of both techniques.

Suprascapular nerve decompression in addition to rotator cuff repair: a prospective, randomized observational trial

BACKGROUND

Tear and retraction of the supraspinatus (SS) and infraspinatus (IS) musculotendinous units and/or their repair may be associated with traction damage to the suprascapular nerve, potentially responsible for pain or weakness of the rotator cuff (RC). Arthroscopic release of the transverse scapular ligament at the suprascapular notch has been advocated to prevent or treat suprascapular nerve impairment associated with RC retraction and/or repair. The effect of this procedure on preoperative normal nerve function is, however, not well studied.We hypothesize that (1) decompression of the suprascapular nerve without preoperative pathologic neurophysiological findings will not improve clinical or imaging outcome and (2) suprascapular decompression will not measurably change suprascapular nerve function.

METHODS

Nineteen consecutive patients with a magnetic resonance arthrography documented RC tear involving SS and IS but normal preoperative electromyography (EMG)/nerve conduction studies of the SS and IS were enrolled in a prospective, controlled trial involving RC repair with or without suprascapular nerve decompression at the suprascapular notch. Nine patients were randomized to undergo, and 10 not to undergo, a decompression of the suprascapular nerve. Patients were assessed clinically (Constant score, mobility, pain, strength, subjective shoulder value), with magnetic resonance imaging and neurophysiology preoperatively and at 3- and 12-month follow-up.

RESULTS

There was no clinically relevant difference between the release and the non-release group in any clinical parameter at any time point. At magnetic resonance imaging, there was a slightly greater increase of fatty infiltration of the IS in the release group without any other differences between the 2 groups. Electromyographically, there were no pathologic findings in the non-release group at any time point. Conversely, 3 of the 9 patients of the release group showed pathologic EMG findings at 3 months, of whom 2 had recovered fully and 1 only partially at 12 months.

CONCLUSION

In the presence of normal EMG findings, suprascapular nerve release added to arthroscopic RC repair is not associated with any clinical benefit, but with electromyographically documented, postoperative impairment of nerve function in 1 of 3 cases. Suprascapular nerve release does not therefore seem to be justified as an adjunct to RC repair if preoperative EMG findings document normal suprascapular nerve function. Based on these findings, the ongoing prospective randomized trial was terminated.

Morphological measurements and classification of the spinoglenoid notch: A three-dimensional reconstruction of computed tomography in the Chinese population

BACKGROUND

The spinoglenoid notch (SGN) is the second most common location for suprascapular nerve (SN) entrapment; however, there are few relative morphological reports on this condition. Hence, the present morphological study mainly explored the anatomical structure and classification of the SGN and the relationship with entrapment of SN.

MATERIALS AND METHODS

Four hundred seventy-eight scapulae were analysed thoroughly and systematically in this study. Anatomical structure and classification of the SGN were observed and measured by a three-dimensional (3D) reconstruction of computed tomography (CT). The measurement results were then analysed and recorded.

RESULTS

Chinese scapulae were classified into three types at the SGN, and it was found that left scapulae had deeper SGN than right ones. Then, significant differences were also noted between sexes. Men had thicker, wider and deeper SGN than women. Type II (small U, 46.04%) was the most common. Type I (large U) was the widest (15.67±1.43mm) and deepest (13.71±2.39mm) compared with other types. Lastly, no significant differences in the above criteria were found in other measurements.

CONCLUSIONS

These morphological measurements of the SGN may help to improve the diagnosis and successful treatment rate of the surgery for the SN entrapment, but the relative clinical trial is necessary to support it.

A new approach for endoscopic neurolysis of the suprascapular nerve at the spinoglenoid notch: A preliminary cadaver study

The suprascapular nerve (SSN) can become compressed at its 2 scapular attachments: the suprascapular and the spinoglenoid notch. The objective of this study was to describe a new arthroscopic approach for SSN neurolysis at the spinoglenoid notch. Ten cadaver shoulders were used. Two were dissected to simulate the "classical" arthroscopic approach and to help in the creation of a new "direct medial retrospinal" approach. Eight other shoulders were used to validate this new approach, with control of the whole juxta-glenoid course of the SSN as criterion of success. The retrospinal posterior approach allowed the entire juxta-glenoid segment of the SSN to be explored in 6 cases out of 8. One exploration was incomplete, another not feasible. SSN neurolysis at the spinoglenoid notch was feasible in cadavers on a retrospinal approach.

Suprascapular Nerve Pathology: A Review of the Literature

Background:

Suprascapular nerve pathology is a rare diagnosis that is increasingly gaining popularity among the conditions that cause shoulder pain and dysfunction. The suprascapular nerve passes through several osseoligamentous structures and can be compressed in several locations.

Methods:

A thorough literature search was performed using online available databases in order to carefully define the pathophysiology and to guide diagnosis and treatment.

Results:

Suprascapular neuropathy diagnosis is based on a careful history and a thorough clinical and radiological examination. Although the incidence and prevalence of the condition remain unknown, it is highly diagnosed in specific groups (overhead athletes, patients with a massive rotator cuff tear) probably due to higher interest. The location and the etiology of the compression are those that define the treatment modality.

Conclusion:

Suprascapular neuropathy diagnosis is based on a careful history and a thorough clinical and radiological examination. The purpose of this article is to describe the anatomy of the suprascapular nerve, to define the pathophysiology of suprascapular neuropathy and to present methodically the current diagnostic and treatment strategies.

Anatomic landmarks for arthroscopic suprascapular nerve decompression

PURPOSE

Arthroscopic suprascapular nerve (SSN) decompression has become a more frequently utilized procedure in the treatment of SSN entrapment and has gained popularity over recent years. Despite increasing technical notes and outcomes information regarding this technique, there remains a paucity of data with respect to clear anatomic guidelines for teaching this procedure. The purpose of this study was to provide guidelines that are visible arthroscopically and palpable externally to allow safer and more efficient surgery for arthroscopic decompression by analysing the superior scapular anatomy with respect to local landmarks.

METHODS

A cadaveric study was used to examine neurovascular structural measurements obtained in twelve cadavera with 23 usable shoulders. Arthroscopic dissection of the pertinent anatomy as determined by previously described approaches was followed by meticulous open regional dissection and measurements of the local landmarks.

RESULTS

Measurements of the pertinent arthroscopic anatomy with respect to local landmarks of the superior shoulder were recorded in 23 shoulders and are included herein. Measurements taken arthroscopically on 22 shoulders revealed that the lateral insertion of the transverse suprascapular ligament to the acromioclavicular joint was 3.6 cm (SD 0.5 cm). One of the anatomic measurements on open dissection had a significant correlation with our subject's demographics and was found between cadaveric height and the linear distance from the lateral acromion to the suprascapular notch (mean distance = 66.53 ± 5.30 mm; Pearson's correlation = 0.739; p = 0.006).

CONCLUSIONS

This cadaveric study describes meaningful landmarks and their measurements, which are identifiable arthroscopically and enable safer surgery in this area. Using these numbers, surgeons can know that it is safe to bluntly dissect to 2.5 cm medial to the acromioclavicular joint (and 5 cm medial to the palpable lateral acromion) before dissection is likely to encounter the SSN or artery. This knowledge will allow surgeons to learn this surgical technique, and for surgical educators to safely teach dissection and release in this uncommonly accessed anatomic region.

Arthroscopic release and labral repair for bifocal compression of the suprascapular nerve

We present a rare case of combined proximal and distal compression of the suprascapular nerve causing supra- and infraspinatus weakness and wasting in a 17-year-old rower. Clinical findings, magnetic resonance imaging and electromyeographic studies confirm this. The case was managed with an arthroscopic approach, consisting of arthroscopic labral repair and decompression of a paralabral cyst, combined with arthroscopic release of the transverse scapular ligament. An excellent result was achieved, with the patient returning to full competitive rowing prior to the 6-month clinical review. This case highlights the interesting nature of bifocal compression of the suprascapular nerve, as well as the successful use of arthroscopic techniques to manage the problem.

An alternative endoscopic portal for suprascapular nerve approach: an anatomic study

PURPOSE

Arthroscopic approaches have been less preferred than open techniques for treating suprascapular nerve entrapment, possibly because current arthroscopic portals are based on distances to reference points, resulting in discrepancies from differing shoulder sizes. This study reports a portal placement based on proportions rather than absolute length.

METHODS

Open dissection (12 left shoulders) and arthroscopy (12 contralateral shoulders) of the suprascapular notch were performed. In left shoulders, the posterolateral prominence of the acromion, the T1 spinous process, and the suprascapular notch were marked (K-wires). Distances from the posterolateral prominence of the acromion to the suprascapular notch and to the T1 spinous process were measured, and the proportion of those distances (distance to the suprascapular notch/distance to the T1 spinous process) was calculated to indicate the portal's location. In right shoulders, arthroscopy anatomically assessed that proportion's reliability.

RESULTS

Median distances from the posterolateral prominence of the acromion to the T1 spinous process and to the suprascapular notch were 175.7 mm (average 180.4, SD 11.8 mm) and 72.3 mm (average 73.9, SD 4.9), respectively. The medians of the proportions of the defined distances were 40.9 % (range 40-42 %) and 41 % (range 39.3-42.1 %), respectively.

CONCLUSION

Locating the portal at the lateral, 41 % of the distance between the posterolateral prominence of the acromion and the T1 spinous process was accurate and reproducible for suprascapular notch visualization. Clinically, this portal seems to eliminate perioperative morbidity by reducing excessive soft-tissue dissection with a shorter arthroscopic route and avoiding the ligamentous damage.

Arthroscopic decompression at the suprascapular notch: a radiographic and anatomic roadmap

BACKGROUND

Arthroscopic decompression of the suprascapular nerve (SSN) at the suprascapular notch is a technically demanding procedure. Additional preoperative and intraoperative information may assist surgeons. The purpose of this study was to (1) identify which imaging modality most accurately represents the anatomic distance to the notch and (2) quantify the mean intraoperative distances from routine arthroscopic portals to the notch.

METHODS

Ten matched pairs of fresh cadaveric shoulders were imaged by roentgenogram, computed tomography (CT), magnetic resonance imaging, and 3-dimensional (3D) CT, followed by arthroscopic SSN decompression at the notch and anatomic dissection. Measurements obtained included the distances from the anterolateral, posterior, and SSN portal sites to the notch in addition to the distance from the anterolateral acromion to the notch. Statistical analysis with Spearman correlation coefficients and Bland-Altman plots were used to determine the correlation and agreement between measurements.

RESULTS

The preoperative imaging modality with the highest correlation to anatomic distances from the anterolateral acromion to the notch was 3D CT (Rs = 0.90, P < .0001). The mean intraoperative distances to the notch from the anterolateral, posterior, and SSN arthroscopic portals were 89 mm, 88 mm, and 49 mm, respectively. The mean anatomic distance from the anterolateral acromion to the notch was 64 mm.

CONCLUSIONS

Preoperative imaging with 3D CT may assist surgeons in performing arthroscopic SSN decompression. Understanding of the mean distances from the portal sites to the suprascapular notch and being cautious of arthroscopic instruments placed beyond 9 cm from laterally based portals may result in safer intraoperative medial dissection.

Arthroscopic all-intra-articular decompression and labral repair of paralabral cyst in the shoulder

BACKGROUND

The purpose of this study was to report the outcomes of all-intra-articular arthroscopic decompression and labral repair in patients with symptomatic paralabral cysts.

METHODS

From 2005 to 2011, 20 consecutive cases of symptomatic paralabral cysts were included in this study. All surgical procedures were conducted with intra-articular arthroscopic decompression by use of a probe through the site of labral tear for cyst evacuation and suture anchor repair for the associated posterosuperior labrum. Clinical scores and magnetic resonance imaging (MRI) were obtained preoperatively and at follow-up. MRI was used to evaluate the size and segmentation of the cyst and the presence of the labral tear.

RESULTS

MRI revealed paralabral cysts in association with labral tears in all cases. Cysts were extended in the spinoglenoid notch with a mean size of 2.5 × 2.6 × 2.2 cm on MRI. Cysts were nonsegmented in 5 cases (25%) and had multiple segments in 15 cases (75%). Mean follow-up was 42.8 ± 21.22 months. The mean visual analog scale score for pain, the American Shoulder and Elbow Surgeons score, and the Simple Shoulder Test score significantly improved at the last follow-up (P < .001, P < .001, and P = .001, respectively). The postoperative MRI study performed at a mean of 6 months for 18 of 20 cases (90%) revealed complete cyst removal. The satisfaction level with surgery was good to excellent in 18 patients, fair in 1 patient, and poor in 1 patient. No complication was related to the surgical procedure.

CONCLUSION

Arthroscopic all-intra-articular decompression and labral repair of paralabral cyst can be a simple and effective treatment, regardless of segmentation or size. It also resulted in complete removal of the cyst at a mean of 6 months postoperatively as revealed by MRI. An additional subacromial procedure might not be necessary for complete decompression.

Peri-articular suprascapular neuropathy

Suprascapular nerve entrapment was first described in 1959 by Kopell and Thompson. Although rare, this condition is among the causes of poorly explained shoulder pain in patients with manifestations suggesting a rotator-cuff tear but normal tendons by imaging studies. Suprascapular nerve entrapment may cause 2% of all cases of chronic shoulder pain. Among the many reported causes of suprascapular nerve entrapment, the most common are para-labral cysts, usually in the spinoglenoid notch, and microtrauma in elite athletes. The potential relevance of concomitant rotator-cuff tears remains debated. Less common causes include tumours, scapular fractures, and direct trauma involving traction. Early diagnosis and treatment are crucial to avoid the development of irreversible muscle wasting. Endoscopic surgery to treat the various causes of suprascapular nerve compression has superseded open nerve release.

Suprascapular neuropathy: what does the literature show?

Suprascapular neuropathy remains a rare, albeit increasingly recognized, diagnosis. Despite its relatively low prevalence, it must be kept in the shoulder surgeon's mind as a potential cause of shoulder pain, particularly in patients where the history, physical examination, and imaging studies do not adequately explain a patient's symptoms or disability. Although challenging to identify, suprascapular neuropathy can be successfully treated. The current literature shows that the location and mechanism of nerve injury are the most important factors guiding management. Different treatment strategies are required, depending on the specific location and type of nerve injury. Controversy regarding if and when to perform an isolated suprascapular nerve release continues. Furthermore, no recommendations regarding suprascapular nerve release in conjunction with rotator cuff repair can be made at this time, and further research is necessary to better delineate the indications in the future.

Recovery of sensory disturbance after arthroscopic decompression of the suprascapular nerve

BACKGROUND

The existence of sensory branches of the suprascapular nerve (SSN) has recently been reported, and sensory disturbance at the lateral and posterior aspect of the shoulder has been focused on as a symptom of SSN palsy. We have performed arthroscopic release of SSN at the suprascapular notch in patients with sensory disturbance since 2006. The purposes of this study were to introduce the arthroscopic surgical technique and investigate postoperative recovery of sensory disturbance.

MATERIALS AND METHODS

The study included 11 men and 14 women (25 shoulders), with an average age of 63.9 years (range, 41-77 years). Arthroscopic decompression of the SSN was performed using a suprascapular nerve (SN) portal as a landmark for approaching the suprascapular notch. Sensory disturbance of the shoulder was evaluated preoperatively and postoperatively. The average follow-up was 18.5 months (range, 12-30 months).

RESULTS

The arthroscopic procedures were performed safely. The preoperative sensory disturbance fully recovered postoperatively in all shoulders.

CONCLUSION

Arthroscopic release of the SSN is a useful procedure for SSN entrapment at the suprascapular notch. The sensory disturbance at the lateral and posterior aspect of the shoulder can be used as one of the criteria of diagnosing SSN palsy, especially in shoulders with massive rotator cuff tear, in which diagnosing and assessing the treatment results of associated SSN palsy is usually difficult.

Suprascapular neuropathy

Suprascapular neuropathy has often been overlooked as a source of shoulder pain. The condition may be more common than once thought as it is being diagnosed more frequently. Etiologies for suprascapular neuropathy may include repetitive overhead activities, traction from a rotator cuff tear, and compression from a space-occupying lesion at the suprascapular or spinoglenoid notch. Magnetic resonance imaging is useful for visualizing space-occupying lesions, other pathological entities of the shoulder, and fatty infiltration of the rotator cuff. Electromyography and nerve conduction velocity studies remain the standard for diagnosis of suprascapular neuropathy; however, data on interobserver reliability are limited. Initial treatment of isolated suprascapular neuropathy is typically nonoperative, consisting of physical therapy, nonsteroidal anti-inflammatory drugs, and activity modification; however, open or arthroscopic operative intervention is warranted when there is extrinsic nerve compression or progressive pain and/or weakness. More clinical data are needed to determine if treatment of the primary offending etiology in cases of traction from a rotator cuff tear or compression from a cyst secondary to a labral tear is sufficient or whether concomitant decompression of the nerve is warranted for management of the neuropathy.

Arthroscopic suprascapular nerve decompression: indications and surgical technique

BACKGROUND

Although entrapment of the suprascapular nerve (SSN) is an infrequent presentation of shoulder pain, proper diagnosis and treatment are critical to prevent chronic supraspinatus and infraspinatus atrophy.

MATERIALS AND METHODS

We present a technique that allows SSN decompression at the spinoglenoid notch or suprascapular notch through the subacromial space.

RESULTS AND CONCLUSIONS

This method allows for facile decompression of the SSN after repair of concomitant shoulder pathology and allows direct visualization of the medial neck of the glenoid to avoid complications of iatrogenic SSN nerve injury from aggressive medial capsule dissection. The purpose of this article is to provide surgeons with a safe, reliable method to decompress the SSN at the suprascapular or spinoglenoid notch.

Suprascapular neuropathy

Suprascapular neuropathy is a relatively uncommon but significant cause of shoulder pain and dysfunction. The suprascapular nerve follows a tortuous course from the neck to the posterior shoulder. There are several potential causes of nerve entrapment along this path, particularly at the vulnerable suprascapular and spinoglenoid notches, where nerve excursion is limited by bony and ligamentous constraints. Additional extrinsic compression may be caused by glenohumeral joint-related ganglion cysts or soft-tissue masses. Traction neuropathy may occur following excessive nerve excursion during overhead sports or as a result of massive, retracted rotator cuff tears in older patients. Diagnosis is based on a careful history, physical examination, focused imaging, and electrodiagnostic studies. In the absence of a clear structural compression or overtensioning of the nerve, treatment initially should be nonsurgical, with activity modification and physical therapy. Discrete nerve compression or failure of nonsurgical measures warrants early surgical intervention. Arthroscopic alternatives to the traditional open suprascapular and/or spinoglenoid notch decompressions have the benefit of simultaneously diagnosing and addressing intra-articular and/or subacromial pathology while minimizing morbidity. In most patients, both open and arthroscopic approaches provide reliable pain relief and improvements in function; return of strength and muscle bulk is less predictable.

Arthroscopic decompression of the suprascapular nerve at the spinoglenoid notch and suprascapular notch through the subacromial space

Suprascapular nerve entrapment can cause disabling shoulder pain. Suprascapular nerve release is often performed for compression neuropathy and to release pressure on the nerve associated with arthroscopic labral repair. This report describes a novel all-arthroscopic technique for decompression of the suprascapular nerve at the suprascapular notch or spinoglenoid notch through a subacromial approach. Through the subacromial space, spinoglenoid notch cysts can be visualized between the supraspinatus and infraspinatus at the base of the scapular spine. While viewing the subacromial space through the lateral portal, the surgeon can use a shaver through the posterior portal to decompress a spinoglenoid notch cyst at the base of the scapular spine. To decompress the suprascapular nerve at the suprascapular notch, a shaver through the posterior portal removes the soft tissue on the acromion and distal clavicle to expose the coracoclavicular ligaments. The medial border of the conoid ligament is identified and followed to its coracoid attachment. The supraspinatus muscle is retracted with a blunt trocar placed through an accessory Neviaser portal. The transverse scapular ligament, which courses inferior to the suprascapular artery, is sectioned with arthroscopic scissors, and the suprascapular nerve is decompressed.