Dorsal minimally invasive plate osteosynthesis of the humerus: Feasibility and risk of nervous injury of a modified technique in an anatomical study.

BACKGROUND

The aim of the study was to design a convenient technique for dorsal minimally invasive plate osteosynthesis (MIPO) of extra-articular fractures of both distal thirds of the humeral shaft as well as to characterise the course and proximity of the radial nerve (RN) and the axillary nerve (AN).

METHODS

The collective consisted of 20 upper extremities of human adult body donors. A 3.5 mm Locking Compression Plate (LCP), an extra-articular distal humerus plate was inserted through a MIPO approach including two incisions. The primary incision was performed 5 cm in lenght on the dorsal side of the lateral epicondyle. An additional 5 cm incision was conducted distal to the humeral deltoid muscle insertion and the RN was depicted. The longest suitable plate was advanced under nerve protection starting distally and fixed by locking screws. A third incision with a length of 5 cm was made beginning at the distal border of the deltoid muscle, and a muscle split was performed to dissect the AN. The respective plate holes, where the AN and RN were located and the distances between the nerves were examined.

RESULTS

The RN was mostly (30%) localised on holes 6 and 7 (starting distally). The AN laid directly on the plate in 65% and on the most proximal plate hole in 12 cases, but was never situated underneath the plate. The distance between the AN and RN was at mean 93.5 mm.

CONCLUSIONS

MIPO via a dorsal method proves to be a noteworthy technique and valuable option as indicated by our results. This 5-5-(5) concept may be performed as a two-incision or three-incision technique for extra-articular fractures of both distal thirds of the humerus.