Effect of suprascapular nerve injury on rotator cuff enthesis

Effect of electroacupuncture combined with rehabilitation techniques on shoulder function in patients with rotator cuff injuries

BACKGROUND

The rotator cuff is located below the acromion and deltoid muscles and comprises multiple tendons that wrap around the humeral head, maintaining shoulder joint stability.

AIM

To explore the effect of electroacupuncture combined with rehabilitation techniques on shoulder function in patients with rotator cuff injuries.

METHODS

We selected 97 patients with rotator cuff injuries treated in the People's Hospital of Yuhuan from February 2020 to May 2023. Patients were grouped using the envelope method.

RESULTS

After treatment, the study group's treatment effective rate was 94.90% (46/49 patients), significantly higher than that in the control group (79.17%, 38/48 cases; P < 0.05). Before treatment, there was no difference in Constant Murley Score (CMS) scores, shoulder mobility, or 36-Item Short Form Health Survey (SF-36) scale scores (P > 0.05). Compared with those before treatment, the CMS scores (including pain, daily living ability, shoulder mobility, and muscle strength), all aspects of shoulder mobility (forward flexion, posterior extension, external rotation, internal rotation), and SF-36 scale scores (including physiological, psychological, emotional, physical, vitality, and health status) were higher in both groups after treatment and significantly higher in the study group (P < 0.05). There was no difference in the occurrence of complications between the two treatment groups (P > 0.05).

CONCLUSION

Electroacupuncture combined with rehabilitation techniques has a good treatment effect on patients with rotator cuff injuries, helps accelerate the recovery of shoulder function, improves the quality of life, and is highly safe.

Effects of adipose-derived cell supplementation on tendon-bone healing in a rat model of chronic rotator cuff tear with suprascapular nerve injury

OBJECTIVE

To investigate the effect of adipose-derived cells (ADCs) on tendon-bone healing in a rat model of chronic rotator cuff tear (RCT) with suprascapular nerve (SN) injury.

METHODS

Adult rats underwent right shoulder surgery whereby the supraspinatus was detached, and SN injury was induced. ADCs were cultured from the animals' abdominal fat. At 6 weeks post-surgery, the animals underwent surgical tendon repair; the ADC (+ve) group (n = 18) received an ADC injection, and the ADC (-ve) group (n = 18) received a saline injection. Shoulders were harvested at 10, 14, and 18 weeks and underwent histological, fluorescent, and biomechanical analyses.

RESULTS

In the ADC (+ve) group, a firm enthesis, including dense mature fibrocartilage and well-aligned cells, were observed in the bone-tendon junction and fatty infiltration was less than in the ADC (-ve) group. Mean maximum stress and linear stiffness was greater in the ADC (+ve) compared with the ADC (-ve) group at 18 weeks.

CONCLUSION

ADC supplementation showed a positive effect on tendon-bone healing in a rat model of chronic RCT with accompanying SN injury. Therefore, ADC injection may possibly accelerate recovery in massive RCT injuries.

Effect of suprascapular nerve injury on muscle and regenerated enthesis in a rat rotator cuff tear model

BACKGROUND

Massive rotator cuff tears (RCTs) are complicated by muscle atrophy, fibrosis, and intramuscular fatty degeneration, which are associated with postoperative tendon-to-bone healing failure and poor clinical outcomes. We evaluated muscle and enthesis changes in large tears with or without suprascapular nerve (SN) injury in a rat model.

METHODS

Sixty-two adult Sprague-Dawley rats were divided into SN injury (+) and SN injury (-) groups (n=31 each), comprising tendon (supraspinatus [SSP]/infraspinatus [ISP]) and nerve resection and tendon resection only cases, respectively. Muscle weight measurement, histological evaluation, and biomechanical testing were performed 4, 8, and 12 weeks postoperatively. Ultrastructural analysis with block face imaging was performed 8 weeks postoperatively.

RESULTS

SSP/ISP muscles in the SN injury (+) group appeared atrophic, with increased fatty tissue and decreased muscle weight, compared to those in the control and SN injury (-) groups. Immunoreactivity was only positive in the SN injury (+) group. Myofibril arrangement irregularity and mitochondrial swelling severity, along with number of fatty cells, were higher in the SN injury (+) group than in the SN injury (-) group. The bone-tendon junction enthesis was firm in the SN injury (-) group; this was atrophic and thinner in the SN injury (+) group, with decreased cell density and immature fibrocartilage. Mechanically, the tendon-bone insertion was significantly weaker in the SN injury (+) group than in the control and SN injury (+) groups.

CONCLUSIONS

In clinical settings, SN injury may cause severe fatty changes and inhibition of postoperative tendon healing in large RCTs. Level of evidence: Basic research, controlled laboratory study.

Correlation of suprascapular notch morphology with suprascapular nerve palsy: a 3D-computed tomography study

Background

The morphology of the suprascapular (SS) notch is a very important factor in treatment of suprascapular nerve (SSN) palsy. Several studies have reported SS notch morphology in cadavers or using a three-dimensional computed tomography (3D-CT); however, none has reported the distribution of SS notch morphology according to the age group. In addition, the correlation between SS notch morphology and SSN palsy remains unclear. The purposes of this study were to investigate the morphological distribution of the SS notch by age group in a large population and to assess the relationship between SS notch morphology and SSN palsy.

Methods

We studied the 3D-CT images of 1063 shoulders in 1009 patients (mean age, 60.8 years; age range, 14-96 years). There were 53 shoulders with SSN palsy and 1010 shoulders without SSN palsy. Morphology of the SS notch was classified by Rengachary's classification (types I-VI). Shoulders with types I-IV were classified into the nonossified superior transverse scapular ligament (STSL) group (group N) and those with types V and VI into the ossified STSL group (group O).

Results

The Rengachary's classifications of the 1063 shoulders were as follows: type I: n = 113, 10.6%; type II: n = 313, 29.4%; type III: n = 383, 36.0%; type IV: n = 109, 10.3%; type V: n = 107, 10.0%; and type VI: n = 38, 3.6%. Mean age was significantly older in the ossified STSL group, and the age was <40 years for only two shoulders in this group. The Rengachary's classifications of the SSN palsy cases were as follows: type I: 7.5%, II: 24.5%, III: 34.0%, IV: 15.1%, V: 13.2%, and VI: 5.7%. There was no statistical difference in age and sex, Rengachary type, or ossification between SSN palsy and non-SSN palsy cases.

Conclusions

Ossification of the STSL was significantly more common in older patients, which suggests age-related change. In addition, no relation was identified between narrow notch or ossification of the STSL with the onset of SSN palsy.

Effect of Arthroscopic Acromioplasty Combined with Rotator Cuff Repair in the Treatment of Aged Patients with Full-Thickness Rotator Cuff Tear and Rotator Cuff Injury

Full-thickness rotator cuff tear and rotator cuff injury are frequently occurring diseases and widely exist in the social population. Surgical repair is the most effective treatment for rotator cuff tears and injuries. With the continuous development of arthroscopy, more and more surgeons choose arthroscopic acromioplasty plus rotator cuff repair for the treatment of rotator cuff injury. However, previously published systematic reviews or meta-analyses still cast doubt on the efficacy of such concomitant procedures for postoperative patient function and pain recovery. In this study, we analyzed the effects of parameters such as shoulder function and acromion morphology on aged patients with full-thickness rotator cuff tear combined with rotator cuff injury treated with arthroscopic acromion plasty and rotator cuff repair. The results showed that arthroscopic acromion plasty and rotator cuff repair helped to promote the joint function recovery of the aged patients with full-thickness rotator cuff tear combined with rotator cuff injury and alleviate the pain of the patients. Compared with simple rotator cuff repair, this technique can increase the postoperative AT and reduce the ACEA and to some extent reduce the risk of postoperative rotator cuff reinjury, which is worthy of promotion.

Suprascapular nerve release does not provide additional benefits in arthroscopic rotator cuff repair surgery: a systematic review and meta-analysis

PURPOSE

To investigate the effect of suprascapular nerve release in arthroscopic rotator cuff repair surgery.

METHODS

This systematic review was performed to include randomized controlled trials (RCTs) and non-RCTs that compared the outcomes of patients who did and did not receive suprascapular nerve release (SSNR) during arthroscopic rotator cuff repair surgery. MEDLINE, Embase, and the Cochrane Central Register of Controlled Trials were searched for relevant studies. Methodological Index for Non-randomized Studies (MINORS) was used for cohort study assessment. The Cochrane risk of bias assessment tool (version 1.0) was used to assess the risk of bias in randomized trials. The primary outcomes were pain and shoulder function. The secondary outcome was the re-tear rate.

RESULTS

Two RCTs and three non-RCTs with a total of 187 patients (90 patients received SSNR and 97 patients did not receive SSNR) were included in this systematic review. The meta-analysis revealed that the SSNR group did not had a more pain reduction, assessed by visual analogue scale, compared to the non-SSNR group. Also, the SSNR group did not have a significantly more improvement in the UCLA score, compared to the non-SSNR group. In addition, there was no significant difference between the two groups in terms of Constant score and re-tear rate.

CONCLUSIONS

The result of this study showed that additional suprascapular nerve release did not provide additional benefit in arthroscopic rotator cuff repair surgery. Routine arthroscopic SSNR is not recommended when treating patients with rotator cuff tear.

LEVEL OF EVIDENCE

Level III.

Abaloparatide Improves Rotator Cuff Healing via Anabolic Effects on Bone Remodeling in a Chronic Rotator Cuff Tear Model of Rat With Osteoporosis: A Comparison With Denosumab

BACKGROUND

Because of poor clinical outcomes, rotator cuff healing in patients with osteoporosis has recently gained attention. Antiresorptive therapy for osteoporosis has been reported to improve healing after repair. However, the comparative effectiveness of anabolic and antiresorptive agents has not been investigated.

HYPOTHESIS

Anabolic therapy with abaloparatide (ABL) would outperform antiresorptive therapy with denosumab (Dmab) to improve rotator cuff healing in the osteoporotic status.

STUDY DESIGN

Controlled laboratory study.

METHODS

A chronic rotator cuff tear model was established in ovariectomy-induced postmenopausal osteoporotic rats. Then, bilateral rotator cuff repairs were conducted in all experimental rats, which were randomly divided into control (CON), Dmab, and ABL groups to receive the corresponding subcutaneous injections. The rats sacrificed at 2 weeks (the early healing period) were used to detect osteoblast and osteoclast activities, related gene expression (osteoclastogenesis, osteogenesis, and chondrogenesis), new bone formation, and mineralization. In the rats sacrificed at 4 and 8 weeks, the bone mineral density and bone architecture at the repaired site were assessed by micro-computed tomography, and rotator cuff healing was evaluated using histological and biomechanical analyses.

RESULTS

At 8 weeks, significantly higher failure load and stiffness were observed in the ABL (25.13 ± 3.54 N, P < .001; 21.65 ± 3.08 N/mm, P < .001; respectively), and Dmab (21.21 ± 2.55 N, P < .001; 16.15 ± 2.07 N/mm, P = .008; respectively) groups than in the CON group (13.36 ± 1.70 N; 11.20 ± 2.59 N/mm; respectively), whereas the ABL treatment provided better failure load and stiffness than Dmab (P = .019; P = .003). Although tendon-to-bone healing was improved by Dmab, the most mature tendon insertion at the interface was observed in the ABL group, including a more organized collagen and fibrocartilage and higher bone quality. ABL significantly promoted bone remodeling via coupling between osteoclasts and osteoblasts (osteoblast to osteoclast ratio: 4.80 ± 0.39; P = .022), thereby stimulating more new bone formation and mineralization at the tendon-to-bone healing interface than Dmab (osteoblast to osteoclast ratio: 3.21 ± 0.75) at 2 weeks. Moreover, ABL had significant effects on gene expression [Runt-realted transcription factor 2 (Runx2, collagen type I-alpha 1 (Col1A1]), and sclerostin for osteogenesis; aggrecan and collagen type II (Col2) for chondrogenesis] in mineralized tissues, indicative of enhanced bone and fibrocartilage formation when compared with the CON and Dmab groups.

CONCLUSION

ABL promoted rotator cuff healing in osteoporotic rats by significantly increasing the mineralized tissue quality and collagen maturity at the reattachment site, leading to improved biomechanical properties, and was superior to Dmab in both biomechanical and histological analyses.

CLINICAL RELEVANCE

Anabolic therapy with ABL may outperform antiresorptive therapy with Dmab in improving outcomes after rotator cuff repair in osteoporotic patients.

Bilateral suprascapular notches are asymmetrically shaped in a third of the Asian population

PURPOSE

The side-to-side differences within an individual's suprascapular notch (SSN) and the clinical characteristics of an ossified superior transverse scapular ligament are unclear. Therefore, the morphological asymmetry of the SSN was investigated, and the factors associated with the ossification of the superior transverse scapular ligament were analyzed.

METHODS

Two hundred and seventy-six computed tomography images were retrospectively analyzed, which included those of both scapulae of Asian patients (mean age, 62.1 ± 19.1 years; males, 197) with high-energy injuries or respiratory diseases. Variations in the SSN were classified into six types based on Rengachary's classification using reconstructed three-dimensional computed tomography. The group with a type VI SSN (completely ossified superior transverse scapular ligament) in at least one scapula was compared with the other group for age, sex, and chronic comorbidities.

RESULTS

Among 276 patients, 95 (34.4%) had asymmetric SSNs and 15 (5.4%) had type VI SSNs. There were no significant differences in age, sex, or comorbidities between both the groups. However, on comparing age groups, the prevalence of type VI SSN was higher in patients aged > 70 years than in those aged < 70 years. Fifteen patients had type VI SSNs, which were unilateral in 10 patients.

CONCLUSION

Asymmetric SSNs were observed in a third of the Asian patients. There were variations in SSNs between individuals and also within an individual. In the cases with suprascapular nerve paralysis, the difference in SSN morphology compared to a healthy side should be considered.

LEVEL OF EVIDENCE

III.

Quantitative Ultrasonographic Analysis of Changes of the Suprascapular Nerve in the Aging Population With Shoulder Pain

Background

Older people are vulnerable to painful shoulder syndromes, the majority of which are derived from degenerative rotator cuff pathologies. The suprascapular nerve (SSN) is closely related to the rotator cuff complex, and its role in shoulder pain has recently been highlighted. This study aimed to explore the differences in SSN among older people with and without shoulder pain, and to investigate the potential factors influencing the nerve size using ultrasound (US) imaging.

Methods

Participants aged ≥60 years were enrolled in the study. A systematic and bilateral US examination of the rotator cuff tendons was performed. The SSN was examined from its origin in the brachial plexus to the spinoglenoid notch of the infraspinatus fossa. The association between the nerve’s cross-sectional area (CSA) and rotator cuff lesions was analyzed using the generalized estimation equation.

Results

Among the 94 participants, 45 (with bilaterally asymptomatic shoulders) were classified into the control group, whereas 49 (with at least one-sided shoulder pain) were classified into the group with shoulder pain. The average CSAs of the SSN at the level of the brachial plexus, supraspinatus fossa, and infraspinatus fossa were comparable between the patients in the control group and those with shoulder pain. There was a higher prevalence of rotator cuff lesions and enlarged distal SSNs in the painful shoulders than in the asymptomatic shoulders of patients with unilateral involvement. A full-thickness tear of the supraspinatus tendon was associated with swelling of the SSN in the supraspinatus fossa (β coefficient = 4.068 mm², p < 0.001).

Conclusion

In the older population, full-thickness tears of the supraspinatus tendon are independently associated with enlargement of the distal SSN. In cases with large rotator cuff tendon tears with poor response to conservative treatments, possible SSN entrapment should be considered and managed accordingly.

Suprascapular Nerve Release: Technique Based on Anatomic Landmarks

Dysfunction of the suprascapular nerve (SSN) is closely related to rotator cuff pathology; nerve dysfunction can lead to cuff disease and vice versa. Owing to repetitive microtrauma during overhead sports or massive cuff tears with significant tendon retraction, the SSN may suffer compression or traction neuropathy at the suprascapular notch. The SSN release technique has already been described. However, on the basis of the many hands-on cadaveric laboratories in which we have participated in the past 20 years, only a few instructors and almost none of the attendants have shown the experience and skill set needed to release the SSN at the suprascapular notch. Therefore, a review of the surgical technique following the anatomic descriptions of an expert anatomist (P.G.) of the shoulder girdle is quite valuable.