Middle trapezius transfer for treatment of irreparable supraspinatus tendon tears- anatomical feasibility study

Abstract

Purpose The purpose of this study was to investigate the anatomical feasibility of a middle trapezius transfer below the acromion for treatment of irreparable supraspinatus tendon tears. Methods This study involved 20 human cadaveric shoulders in 10 full-body specimens. One shoulder in each specimen was dissected and assessed for muscle and tendon extent, force vectors, and distance to the neurovascular structures. The opposite shoulder was used to evaluate the surgical feasibility of the middle trapezius transfer via limited skin incisions along with an assessment of range of motion and risk of neurovascular injury following transfer. Results The harvested acromial insertion of the middle trapezius tendon showed an average muscle length of 11.7 ± 3.0 cm, tendon length of 2.7 ± 0.9 cm, footprint length of 4.3 ± 0.7 cm and footprint width of 1.4 ± 0.5 cm. The average angle between the non-transferred middle trapezius transfer and the supraspinatus was 33 ± 10° in the transversal plane and 34 ± 14° in the coronal plane. The mean distance from the acromion to the neurovascular bundle was 6.3 ± 1.3 cm (minimum: 4.0 cm). During surgical simulation there was sufficient excursion of the MTT without limitation of range of motion in a retracted scapular position but not in a protracted position. No injuries to the neurovascular structures were noted. Conclusion Transfer of the acromial portion of the middle trapezius for replacement of an irreparable supraspinatus seems to be feasible in terms of size, vector, excursion, mobility and safety. However, some concern regarding sufficiency of transfer excursion remains as scapula protraction can increase the pathway length of the transfer. Level of evidence Basic Science Study/Anatomical Study

Rotator cuff irreparability or failure of repair (re-tear): technical note on middle trapezius tendon transfer for reproduction of supraspinatus function

“….To overcome the latter limitation of LTTT, MTTT to SSP footprint is to exert a force vector almost collinear to that of SSP; so offering a biomechanical rationale for MTTT as a management option of irreparable SSP tear [ 8 , 13 ].…”

“…30° and 24° in the transverse and coronal planes respectively) following transfer. However in this study, mechanical block of the transferred tendon against the acromion (in protracted-scapula position) was a concern [ 13 ].…”

“…5 cm) rather than main bulk of the middle trapezius insertion. Technical differences of the currently reported technique from that of Moroder et al are summarized in Table 3 [ 13 ].…”

“….For reproduction of SSP function; middle trapezius tendon transfer (MTTT) might offer a number of potential biomechanical (e.g., almost collinear force vector with that of SSP), biological (e.g., abundant blood supply) and technical (e.g., simplified tendon harvest/convenient room of SSP fossa for gliding motion of tendon reconstruct) advantages which in turn are to result in almost re-normalized gleno-humeral (GH) kinematics and satisfactory clinical outcomes especially with regard to restoration of active GH elevation [ 8 , 13 , 14 , 18 ].…”

“….In a novel cadaveric technical description, Moroder et al released the middle trapezius tendon from its acromial (lateral) attachment in order to be transferred to the footprint of a simulated SSP tear; concluding that insufficient length and dynamic mechanical block (against the acromion) of the transferred tendon remain questionable possibilities specifically in protracted-scapular position [ 13 ].…”