Percutaneous arthroscopic release of the suprascapular nerve

Clinical Outcomes of Arthroscopic Suprascapular Nerve Decompression for Suprascapular Neuropathy

PURPOSE

To report clinical outcomes following arthroscopic suprascapular nerve (SSN) decompression for suprascapular neuropathy at the suprascapular and/or spinoglenoid notch in the absence of major concomitant pathology.

METHODS

We retrospectively reviewed prospectively collected data of 19 patients who underwent SSN release at the suprascapular and/or spinoglenoid notch between April 2006 and August 2017 with ≥2 years of follow-up. Patients who underwent concomitant rotator cuff or labral repairs or had severe osteoarthritis were excluded. Pre- and postoperative strength and patient-reported outcomes were collected, including the American Shoulder and Elbow Surgeons (ASES), Single Assessment Numerical Evaluation (SANE), Quick Disabilities of the Arm, Shoulder, and Hand (QuickDASH), 12-item Short Form (SF-12), and satisfaction. Complications and revisions were recorded.

RESULTS

At a mean final follow-up of 4.8 years, pre- to postoperative ASES (64.9 ± 18.7 versus 83.5 ± 23.1; P = .018), QuickDASH (28.7 ± 17.2 versus 12.7 ± 17.1; P = .028), SANE (64.3 ± 16.4 versus 80.8 ± 22.3; P = .034), and SF-12 PCS (41.1 ± 10.8 versus 52.3 ± 5.8; P = .007) scores all significantly improved. Median strength for external rotation improved significantly (4 [range 2 to 5] versus 5 [range 3 to 5]; P = .014). There was no statistically significant improvement in median strength for abduction (4 [range 3 to 5] versus 5 [5]; P = .059). Median postoperative satisfaction was 9 (range 1 to 10), with 8 patients (50%) rating satisfaction ≥9. No complications were observed, and no patients went on to revision surgery.

CONCLUSION

Arthroscopic SSN decompression for suprascapular neuropathy at the suprascapular and/or spinoglenoid notch in the absence of major concomitant glenohumeral pathology results in good functional outcomes with significant improvements from before to after surgery.

LEVEL OF EVIDENCE

IV, therapeutic case series.

"Isolated" Suprascapular Neuropathy: Compression, Traction, or Inflammation?

BACKGROUND

Several hypotheses have been proposed for the pathophysiology of suprascapular nerve (SSN) palsy, including compression, traction, and nerve inflammation.

OBJECTIVE

To provide insight into the pathophysiology of isolated nontraumatic SSN palsy by performing critical reinterpretations of electrodiagnostic (EDX) studies and magnetic resonance (MR) images of patients with such diagnosis.

METHODS

We retrospectively reviewed all patients referred to our institution for the past 20 yr with a diagnosis of nontraumatic isolated suprascapular neuropathy who had an upper extremity EDX study and a shoulder or brachial plexus MR scan. Patient charts were reviewed to analyze their initial clinical examination, and their original EDX study and MR images were reinterpreted by an experienced neurologist and a musculoskeletal radiologist, respectively, both blinded from the authors' hypothesis and from each other's findings.

RESULTS

Fifty-nine patients were included. Fifty of them (85%) presented with at least 1 finding that was inconsistent with an isolated SSN palsy. Forty patients (68%) had signs on physical examination beyond the SSN distribution. Thirty-one patients (53%) had abnormalities on their EDX studies not related to the SSN. Twenty-two patients (37%) had denervation atrophy in other muscles than the spinati, or neural hyperintensity in other nerves than the SSN on their MR scans, without any evidence of SSN extrinsic compression.

CONCLUSION

The great majority of patients with presumed isolated SSN palsy had clinical, electrophysiological, and/or imaging evidence of a more diffuse pattern of neuromuscular involvement. These data strongly support an inflammatory pathophysiology in many cases of "isolated" SSN palsy.

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.

MRI appearance of the superior transverse scapular ligament

OBJECTIVE

The superior transverse scapular ligament (STSL) forms the roof of the suprascapular notch, which is the most common location of entrapment of the suprascapular nerve, a cause of shoulder pain and weakness. The purpose of this study is to determine the frequency of visualization of the STSL on routine shoulder MRIs, to identify the sequences and imaging planes on which it is visualized most frequently, and to describe its typical MRI appearance, none of which have been previously addressed in the radiologic literature.

MATERIALS AND METHODS

One hundred twenty-one consecutive shoulder MRIs were reviewed for the presence or absence of the STSL, including the imaging plane and sequence that best depicted the ligament. Dimensions of the ligament were recorded.

RESULTS

Fifty four of 121 shoulder MRIs were technically adequate for visualization of the STSL, and it was identified on 51 of these studies (94%). There was no statistically significant difference between 1.5-T and 3-T systems. The best individual sequence for visualizing the STSL was the sagittal T1-weighted sequence, in which the STSL was visible on 75/80 technically adequate sequences (94%). The sagittal plane was the best plane for visualizing the STSL, in which it was visible on 65/69 technically adequate studies (94%). The STSL on average measured 12.8 ± 1.5 mm in transverse dimension.

CONCLUSIONS

The STSL can be visualized on the majority of shoulder MRIs and is best seen on sagittal T1-weighted images on our imaging protocol. Evaluation of the STSL can potentially help in identifying pathologic conditions affecting the suprascapular nerve.

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.

Quantification of the learning curve for arthroscopic suprascapular nerve decompression: an evaluation of 300 cases

PURPOSE

This study aimed to quantify the learning curve for arthroscopic suprascapular nerve decompression (SSND) using the log-linear model.

METHODS

Three hundred consecutive patients underwent arthroscopic SSND by release of the transverse scapular ligament at the suprascapular notch by a single surgeon. Cases with a bony suprascapular nerve foramen were excluded. The arthroscopic SSND time was defined as the time from the beginning of shaving the soft tissue medial to the acromioclavicular joint until the completion of the transverse scapular ligament release. Regression analysis was applied to predict the time required for SSND on the basis of the cumulative case volume after logarithmic transformation of both statistics.

RESULTS

The mean SSND time decreased from the first 50 cases (mean, 29.5 minutes) to the last 50 cases (mean, 6.2 minutes). The estimated SSND times of the first and last 50 cases were 25.1 minutes and 5.5 minutes, respectively. A significant linear correlation was observed between the SSND time and the cumulative volume of cases after logarithmic transformation (r(2) = 0.481, P < .01), and the best-fit linear equation was calculated as log y = -0.52 log x + 4.6, where y represents the estimated SSND time and x represents the cumulative volume of cases, resulting in an estimated learning rate of 69.7% (which equals 2(-0.52)).

CONCLUSIONS

This study presents the overall time reduction in arthroscopic SSND in support of a learning-curve effect. Furthermore, this study quantifies the learning rate, estimated as approximately 70%, indicating that the time required for arthroscopic SSND can decrease by up to 30% when the cumulative volume of cases doubles.

LEVEL OF EVIDENCE

Level II, prospective comparative study.

Robot-assisted surgery of the shoulder girdle and brachial plexus

New developments in the surgery of the brachial plexus include the use of less invasive surgical approaches and more precise techniques. The theoretical advantages of the use of robotics versus endoscopy are the disappearance of physiological tremor, three-dimensional vision, high definition, magnification, and superior ergonomics. On a fresh cadaver, a dissection space was created and maintained by insufflation of CO2. The supraclavicular brachial plexus was dissected using the da Vinci robot (Intuitive Surgical, Sunnyvale, CA). A segment of the C5 nerve root was grafted robotically. A series of eight clinical cases of nerve damage around the shoulder girdle were operated on using the da Vinci robot. The ability to perform successful microneural repair was confirmed in both the authors' clinical and experimental studies, but the entire potential of robotically assisted microneural surgery was not realized during these initial cases because an open incision was still required. Robotic-assisted surgery of the shoulder girdle and brachial plexus is still in its early stages. It would be ideal to have even finer and more suitable instruments to apply fibrin glue or electrostimulation in nerve surgery. Nevertheless, the prospects of minimally invasive techniques would allow acute and subacute surgical approach of traumatic brachial plexus palsy safely, without significant and cicatricial morbidity.

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.

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.

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.

Arthroscopic decompression of a bony suprascapular foramen

Arthroscopic decompression of the suprascapular nerve by transection of the transverse scapular ligament has only recently been described. Arthroscopic decompression of a bony suprascapular notch foramen has not been previously reported. This article presents a case report and outlines an arthroscopic technique to safely decompress a bony suprascapular notch. In the subacromial space, a lateral portal is used for viewing and a posterior portal for instrumentation. The medial wall of the subacromial bursa located behind the acromioclavicular joint is debrided with the shaver facing laterally and superiorly. The posterior acromioclavicular artery is routinely coagulated. A superomedial portal is now established using spinal needle localization. A smooth 5.5-mm cannula is placed in this portal and the coracoclavicular ligaments (trapezoid and conoid) are followed to the coracoid. The smooth cannula serves nicely to sweep and retract the suprascapular artery and associated fibrofatty tissue from the field of view while allowing instrumentation and visualization of the suprascapular notch. The course of the suprascapular nerve and morphology of the notch is confirmed. A Kerrison punch rongeur, routinely used in spine surgery, is introduced through the superomedial portal and a notchplasty is performed safely, allowing decompression of the suprascapular nerve.