The Anatomic Study Of Total Hip Arthroplasty:the Course Of Superior Gluteal Nerve Within Minimally Invasive Total Hip Replacement(OCM Approach)

Purpose OCM approach is not an ideal neuromuscular clearance in theory.To make it clear that the actual probability of nerve injury in operation process and to reduce the risk of nerve damage in THA,this study will further inspect in the strike of the branch of superior gluteal nerve innervating tensor fasciae latae muscle.Methods We conducted a total of six examples’ autopsy study using OCM approach and looked for the superior gluteal nerve branch innervating tensor fasciae latae muscle.The body length,the location of trunk and branch of superior gluteal nerve and the distance from superior gluteal nerve branch innervating tensor fasciae latae muscle to anterior superior iliac spine and greater trochanter were recorded respectively,as well as nerve morphology and accompanying blood vessels.The same one doctor performed 20 cases of surgery.We checked the integrity of superior gluteal nerve branch innervating tensor fasciae latae muscle before we closed the incision.The incision was within the straight line between anterior superior iliac spine and greater trochanter and 3.5cm away from anterior superior iliac spine.When prosthesis installation was completed,we exposed superior gluteal nerve branch innervating tensor fasciae latae muscle between tensor fasciae latae muscle and gluteus medius to check whether the nerve was damaged.Results There were 11 cases in which we found the strike of target nerve successfully.In 10 of 11 cases,superior gluteal nerve penetrated into tensor fasciae latae muscle directly from clearance between gluteus medius and gluteus minimus.The distance from the point where superior gluteal nerve penetrated into tensor fasciae latae muscle to anterior superior iliac spine was 3.31±0.7cm.The distance from the point where superior gluteal nerve penetrated into tensor fasciae latae muscle to femoral greater trochanter was 6.5±1.3cm.However,a special variation was founded.In this case,superior gluteal nerve walk down within gluteus medius fascia about 3cm,and then penetrate into tensor fasciae latae muscle.There were also accompanying blood vessels between tensor fasciae latae muscle and gluteus medius.Strikes of target nerve in the 20 patients who accepted THA with OCM approach were the exposed successfully.We did not find variation this time.We found 3 cases of nerve injuries by the end of surgeries.The distance from the point where superior gluteal nerve penetrated into tensor fasciae latae muscle to anterior superior iliac spine was 3.3±0.4cm.Conclusion Our research emphasize the classic OCM approach,because it is the most commonly way we use in THA in our department.Sometimes we extend proximal incision to decrease soft tissue tension because of limited incision exposure,however,it may hurt gluteus medius and increase probability of adjacent nerve injury like the branch of superior gluteal nerve.Due to Individual Difference,the interrelation of superior gluteal nerve and femoral greater trochanter is unreliable.The point where superior gluteal nerve appear in gluteus medius is relatively fixed,the distance to anterior superior iliac spine are mostly within 3.5cm expect a variable.It can be reduced that the area 3.5 cm away from anterior superior iliac spine were relatively safe area.