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Ossification of the suprascapular ligament: A risk factor for suprascapular nerve compression?

Authors:
  • Seattle Science Foundation

Abstract and Figures

Entrapment of the suprascapular nerve at the suprascapular notch may be due to an ossified suprascapular ligament. The present study was conducted in order to investigate the incidence of this anomaly and to analyze the resultant bony foramen (foramen scapula) for gross nerve compression. We evaluated 104 human scapulae from 52 adult skeletons for the presence of complete ossification of the suprascapular ligament. When an ossified suprascapular ligament was identified, the diameter of the resultant foramen was measured. Also, the suprascapular regions of 50 adult cadavers (100 sides) were dissected. When an ossified suprascapular ligament was identified, the spinati musculature was evaluated for gross atrophy and the diameters of the resultant foramen scapulae and the suprascapular nerve were measured. Immunohistochemical analysis of the nerve was also performed. For dry scapular specimens, 5.7% were found to have an ossified suprascapular ligament. The mean diameter of these resultant foramina was 2.6 mm. For cadavers, an ossified suprascapular ligament was identified in 5% of sides. Sections of the suprascapular nerve at the foramen scapulae ranged from 2 to 2.8 mm in diameter. In all cadaveric samples, the suprascapular nerve was grossly compressed (~10-20%) at this site. All nerves demonstrated histologic signs of neural degeneration distal to the site of compression. The presence of these foramina in male cadavers and on right sides was statistically significant. Based on our study, even in the absence of symptoms, gross compression of the suprascapular nerve exists in cases of an ossified suprascapular ligament. Asymptomatic patients with an ossified suprascapular ligament may warrant additional testing such as electromyography.
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Editors Joe F. de Beer and Deepak N. Bhatia. Printed and published by Medknow Publications and Media Pvt. Ltd. on behalf of Cape Shoulder Institute, Cape Town, South Africa and Printed at
Dhote Offset Technokrafts Pvt. Ltd., Jogeshwari, Mumbai, India and published at B5-12, Kanara Business Centre, Ghatkopar, Mumbai, India.
Volume 7 Issue 1
Jan-Mar 2013
}Coracoid bone graft osteolysis after Latarjet procedure: A comparison study
between two screws standard technique vs mini-plate fixation
}A biomechanical assessment of superior shoulder translation after reconstruction
of anterior glenoid bone defects: The Latarjet procedure versus allograft
reconstruction
}Beyond the peak of the anterior glenoid rim: A cadaveric study
}Ossification of the suprascapular ligament: A risk factor for suprascapular nerve
compression?
}Digital photography for assessment of shoulder range of motion: A novel clinical
and research tool
}Supraspinatus and infraspinatus compartment syndrome following scapular
fracture
}Arthroscopic autograft reconstruction of the inferior glenohumeral ligament:
Exploration of technical feasibility in cadaveric shoulder specimens
}Metal markers for radiographic visualization of rotator cuff margins: A new
technique for radiographic assessment of cuff repair integrity
C o n t e n t s
19 International Journal of Shoulder Surgery - Jan-Mar 2013 / Vol 7 / Issue 1
Original Article



R. Shane Tubbs
1
, Carl Nechtman
1
, Anthony V. D’Antoni
2
, Mohammadali M. Shoja
1
,
Martin M. Mortazavi
1
, Marios Loukas
3
, Curtis J. Rozzelle
1
, Robert J. Spinner
4
ABSTRACT
Introduction: Entrapment of the suprascapular nerve at the suprascapular notch may be due

the incidence of this anomaly and to analyze the resultant bony foramen (foramen scapula) for

Materials and Methods: We evaluated 104 human scapulae from 52 adult skeletons for the

           
            



Results:            






Conclusions: 


Key words:

INTRODUCTION
        
        

       
     
       







       




Alabama,


Medicine, New York, USA,
Department


4

Clinic, Rochester, MN, USA

Dr. R. Shane Tubbs,



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Website:
www.internationalshoulderjournal.org
DOI:
10.4103/0973-6042.109882
Quick Response Code:
Tubbs, et al.
International Journal of Shoulder Surgery - Jan-Mar 2013 / Vol 7 / Issue 1 20
     







       
    


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










     


      

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





MATERIALS AND METHODS






       


      




 





     

 Pt

RESULTS




    



           









  
Figure 2: Schematic drawing illustrating compression of the left
suprascapular nerve within the foramen scapulae as found in all of
our cadaveric specimens with such a foramen. Note that this is a
posterior view
Figure 1:        
ligament (L) resulting in the foramen scapulae (seen above the L).
For reference, note the spine (S), coracoid process (C) and acromion
(A) of the scapula
Tubbs, et al.
21 International Journal of Shoulder Surgery - Jan-Mar 2013 / Vol 7 / Issue 1
      







    P   


DISCUSSION
         




    





    
       
      

  
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   

  et al
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 
et al
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

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
       
  


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 
        
    
   




       
      



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          

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       
       
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       
   





  

 



CONCLUSIONS





REFERENCES
       




 

 
     

 
    
    

         
Figure 3: Histologic specimen noting signs of suprascapular nerve

          
ligament and notes vascular hyalinization and thickening of the epi
and perineuria (Trichrome ×44)
Tubbs, et al.
International Journal of Shoulder Surgery - Jan-Mar 2013 / Vol 7 / Issue 1 22


          


  



 

 
          



 
      
      

 

  


       
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  
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 
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 
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        
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           
     
Source of Support: Nil,  None declared.
... Según Agrawal et al. (2015) el nervio supraescapular da ramos sensitivos para el hombro y para los ligamentos coracohumeral y coracoacromial y bursa serosa subacromial (Tubbs et al., 2013). Según Podgórski et al. (2014) la incisura escapular también permite el paso de la vena supraescapular. ...
... Ocasionalmente, la incisura escapular puede ser reemplazada por la existencia de un foramen (Das et al., 2007;Kannan, 2014;Singh et al., 2018) debido a que los dos márgenes de la incisura que conectan el margen superior de esta se pueden fusionar, debido a la osificación del ligamento transverso superior de la escápula, lo que lleva a la reducción de su tamaño original, considerándose un factor precipitante de atrapamiento del nervio supraescapular (Das et al., 2007;Podgórski et al., 2014;Joy, 2015). De esta manera, la presencia de dicha osificación ligamentosa se considera un factor de riesgo neuropático del nervio supraescapular (Tubbs et al., 2013, Podgórski et al., 2014Singh et al., 2018) por lo que su conocimiento radiológico puede ser útil en el diagnóstico y tratamiento del síndrome de compresión (Das et al., 2007). ...
... Sin embargo, se torna necesario destacar que la osificación del ligamento escapular transverso superior puede darse en cualquier etapa de la vida del individuo. Tubbs et al. (2013) visualizaron el foramen escapular en el 5,7 % de los casos de un total de 104 escápulas. Según Zahid et al. (2014) la prevalencia del ligamento escapular transverso superior osificado fue del 1,96% en la población paquistaní. ...
Article
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Occasionally the scapular notch can be replaced by a bony foramen product of the ossification of the superior transverse scapular ligament. This bone formation is considered a precipitating factor for compression of the suprascapular nerve. One hundred and ninety-five adult scapulae from Colombian (114 scapulae) and Chilean (81 scapulae) university osteotheques were studied macroscopically to determine the presence of a bony scapular foramen. Both scapulae of the same Colombian individual (1.75% of the total) presented the scapular foramen and one left scapula (1.23%) presented this formation in a Chilean individual. The prevalence of ossification of the superior transverse scapular ligament is highly variable in the different studies and tends to be less than 10%; however, it can become a risk factor due to entrapment or compression of the suprascapular nerve, a fact known as suprascapular neuropathy.
... One of the most common risk factors for developing suprascapular neuropathy is a narrow suprascapular notch, particularly of type VI based on a Reganchary classification system [3,9]. Existing evidence from literature, however, suggests that the percentage of suprascapular notches with type VI differs by population, ranging from as low as 0.7% to as high as 9.7% in some areas [3,4,[9][10][11][12]. ...
... The distribution of suprascapular notch Rengachary types and their relationships with anthropometric dimensions of the entire scapula has been extensively investigated in numerous populations, including Uganda, Kenya, the United States and India [3,[9][10][11]13,14]. The incidence of complete ossification of the suprascapular ligament has received a lot of attention. ...
... Numerous studies reported on the variations of the morphology and morphometric dimensions of the suprascapular notch in various populations [11,13,14]. These dimensional variations are population specific and may be attributed to genetic, environmental and regional differences [9][10][11]. Clinically, such variations have profound implications in the management of patients with symptoms associated with suprascapular neuropathy particularly suprascapular nerve entrapment associated with complete ossification of the suprascapular ligament [13][14][15]. ...
Article
Introduction: the anatomy of the suprascapular notch and its relationship to scapular dimensions are critical in the management of suprascapular neuropathies. Individuals show considerable differences in the dimensions of the suprascapular notch across populations. The purpose of this study was to determine the morphology and morphometric dimensions of the suprascapular notch in adult Malawian cadavers and to suggest clinical implications associated with complete ossification of the suprascapular ligament. Methods: adult dry scapulae from undetermined sex specimens (n=125) obtained from the skeletal collection at Kamuzu University of Health Sciences were classified according to the Rengachary categorization method to assess the suprascapular notch superior transverse distance, mid transverse distance, depth, scapula length and width using a standard Vernier caliper. Results: the most prevalent suprascapular notch class was type I, which was found in 46 (36.8%) of all scapulae. Type VI was the least common, found in only 1 (0.8%) of the scapulae. The mean notch superior transverse distance was 1.3 ± 0.6 cm, while the mean maximum depth was 0.6 ± 0.3 cm. Only the differences in depth, however, were statistically significant (p=0.001). Conclusion: the current study has described the morphology and morphometry of the suprascapular notch in relation to the risk of suprascapular nerve entrapment associated with complete ossification of the suprascapular ligament. Our sample population generally showed smaller suprascapular notch and scapular dimensions than other populations. This should be considered during the management of suprascapular neuropathy and preoperative planning of surgical operations of the shoulder region.
... The study by Tubbs et al demonstrating a compressed SN in 5 SSN out of 50 cadaveric studies was evidenced by histolopathological examination of the SN, and the diameter of those SSN was at critical stenosed range of 1.8 to 3.0 mm. 4 That make the study by Tubbs et al 4 case specific and not necessary cohort in the absence of SSN stenosis. Meanwhile, Tsikouris et al 1 demonstrated smaller in size SSN in association to SL ossification in their population sample but those SSN were not critically stenosed. ...
... One of the most important risk factors for suprascapular nerve entrapment is a completely ossified STSL. 8,11 Studies report evidence of neural degeneration in nerve specimens of STSL ossification. 12 Studies report a wide variability of ossified STSL. ...
Article
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The present study was conducted to highlight the variations of suprascapular foramen in an extensive osteological study of 100dry scapulae. Attempt was also made to establish a comparison between osteological and radiological appearance of such variations. In only one scapula, an ossified superior transverse scapular ligament was discovered which converted the suprascapular notch into a suprascapular foramen. The ossified superior transverse scapular ligament presented as an oblique bony ridge, fan shaped in appearance. Conversion of suprascapular notch into a foramen is considered as a potential risk factor for the suprascapular nerve entrapment syndrome. The present day neurosurgeons, radiologists and orthopedic surgeons should be aware of such bony abnormalities, as these are imperative in preoperative radiological assessment and intraoperative modification of surgical procedures during arthroscopic decompression of suprascapular nerve.
... The suprascapular nerve is formed by fibres from C5, C6 and occasionally from C4 (Tubbs et al, 2013). It supplies the supraspinatus and infraspinatus, and sensory branches to rotator cuff muscles and ligamentous structures of the shoulder and acromioclavicular joints (Jacob et al, 2012). ...
Article
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Suprascapular notch (SSN) of the scapular is a depression on the lateral part of its superior border, which is bridged by the superior transverse scapular ligament as it transmits the suprascapular nerve to the supraspinous fossa. Variations in morphology of the SSN have been associated with suprascapular nerve entrapment. The aim of this study was to characterize the morphological variations of suprascapular notch in Nigerian dry scapulae. A total of 193 human dry scapulae (96 Right and 97 Left) were studied. The variables of study included the shape of the SSN, superior transverse diameter (STD), inferior transverse diameter (ITD) and maximum depth (MD) of the SSN. The metric variables were measured with a Vernier Calliper. The SSN was classified based on Renganchary et al classification. The values of the STD, ITD, and MD were 1.285 ± 0.536, 0.724 ± 0.316 and 0.997 ± 0.441 respectively. These values showed no statistical difference between the right and the left sides. The prevalence of the types of SSN (in decreasing order) were type III (71%), type II (22%), type I & V (3% each) type IV (1%) and type VI (0%). The findings of the present study showed that type III was the most prevalent type while type VI (formed by complete ossification of the suprascapular ligament) was not found in the study.
... 14 It is worth mentioning that ossification of the STSL has been histologically proven to lead to compression of the SSN even without evident neuropathy-associated symptoms. 26 The mean middle-transverse diameter was also calculated after the SNs were distinguished based on their content. The diameter for type-I notches was 8 14 The fact, no statistically significant difference was found between the different types of SN diameters which indicates that the diameter is not bigger in an SN type III in which both suprascapular vessels pass through the notch with the SSN, and as a result, an SSN compression inside the canal may be more likely to occur. ...
Article
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Background The suprascapular notch (SN) represents the point along the route of the suprascapular nerve (SSN) with the greatest potential risk for injury and compression. Thus, factors reducing the area of the notch have been postulated for suprascapular neuropathy development. Methods Thirty-one fresh-frozen shoulders were dissected. The contents of the SN were described according to four types as classified by Polguj et al and the middle-transverse diameter of the notch was measured. Also, the presence of an ossified superior transverse scapular ligament (STSL) was identified. Results The ligament was partially ossified in 8 specimens (25.8%), fully ossified in 6 (19.35%), and not ossified in the remaining 17 (54.85%). The mean middle-transverse diameter of the SN was 9.06 mm (standard deviation [SD] = 3.45). The corresponding for type-I notches was 8.64 mm (SD = 3.34), 8.86 mm (SD = 3.12) was for type-II, and 14.5 mm (SD = 1.02) was for type III. Middle-transverse diameter was shorter when an ossified ligament was present (mean = 5.10 mm, SD = 0.88 mm), comparing with a partially ossified ligament (mean =7.67 mm, SD = 2.24 mm) and a nonossified one (mean = 11.12 mm, SD = 2.92 mm). No statistically significant evidence was found that the middle-transverse diameter depends on the number of the elements, passing below the STSL. Conclusion Our results suggest that SSN compression could be more likely to occur when both suprascapular vessels pass through the notch. Compression of the nerve may also occur when an ossified transverse scapular ligament is present, resulting to significant reduction of the notch's area.
Article
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 three-dimensional computed tomography (3D-CT); however, none has reported the distribution of SS notch morphology according to 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 classification (types I–VI). Shoulders with types I–IV were classified into the non-ossified 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 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%; type VI: n = 38, 3.6%. Mean age was significantly older in the ossified STSL group, and age was <40 years for only two shoulders in this group. The Rengachary 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, 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.
Article
PurposeThe 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.ResultsAmong 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 evidenceIII.
Book
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In recent years, tunnel syndromes or entrapment neuropathies have become increasingly recognized as a cause of pain and dysfunction in various parts of the human body. The third edition continues to probe the origins of these painful syndromes and to propose the possible causes that lead to them.This edition,similar to the preceding two,is intended to give a quick overview of the definition ,anatomy, etiology, clinical symptoms and signs,and treatment of tunnel syndromes. Like the first two editions, this book is intended for a wide spectrum of medical students, general practitioners, and specialists from diferent fields of medicine, not only those whose primary concern is surgery. The third edition of the book has nine new syndromes, bnringing the total number described in the book to more than 50.
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Complete ossification of the superior transverse scapular ligament is generally considered to be rare and has not been previously described in a Nigerian. In the diagnosis of suprascapular nerve entrapment syndrome, variations in the anatomy of the superior transverse scapular ligament must be considered as possible etiologic factors, as illustrated by this case report
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The morphology of the suprascapular notch has been associated with suprascapular entrapment neuropathy, as well as injury to the suprascapular nerve in arthroscopic shoulder procedures. This study aimed to describe the morphology and morphometry of the suprascapular notch. The suprascapular notch in 138 scapulae was classified into six types based on the description by Rengachary. The suprascapular notch was present in 135 (97.8%) scapulae. Type III notch, a symmetrical U shaped notch with nearly parallel lateral margins, was the most prevalent type, appearing in 40 (29%) scapulae. The mean distance from the notch to the supraglenoid tubercle was 28.7 ± 3.8 mm. This varied with the type of notch, being longest in type IV (30.1 ± 1.8 mm) and shortest in type III (27.3 ± 2.3 mm). The mean distance between the posterior rim of the glenoid cavity and the medial wall of the spinoglenoid notch at the base of the scapular spine was found to be 15.8 ± 2.2 mm. Type III notch was the most prevalent, as found in other populations. In a significant number of cases the defined safe zone may not be adequate to eliminate the risk of nerve injury during arthroscopic shoulder procedures, even more so with type I and II notches.
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