Applied Anatomy Of Anteromedial Approach Under Elbow Arthroscopy

Background:Minimally invasive surgery is a high-tech in medicine,a technological innovation in the history of modern medical development,and a new milestone.As an important part of minimally invasive surgery,arthroscopy has the advantages of minimally invasive surgery,rapid recovery and early functional exercise.It has played an extremely important role in bone and joint surgery.At present,the development of knee arthroscopy technology in China has been mature,and the clinical application of other arthroscopic surgery is relatively less.The elbow joint cavity is narrow and irregular,the anatomical structure is complex,and the operation is limited,so the complications are more.¹Although elbow arthroscopy technology was developed earlier,the incidence of complications and the risk of complications in elbow arthroscopic surgery are high.There are few related papers at home and abroad.We reviewed the literature and found that there were three different approaches to the anteromedial approach of the elbow joint:the first?A?is Andrew's first proposal that the distal end of the medial epicondyle of the humerus is 2 cm and the front is 2 cm;²the second?B?is Lindenfeld's proposal that the distal end of the medial epicondyle of the humerus be 1 cm and the anterior 1 cm;³ the third?C?is Verhaar proposed distal 2 cm and anterior 1 cm of the medial epicondyle of the humerus⁴.Which is safer and more effective,there is no comparison,lack of experimental demonstration.In this experiment,we observed the size of the field of vision,the degree of difficulty and the flexibility of operation of three approaches on the same fresh thawed cadaveric elbow joint specimens,to explore the effectiveness of three different anteromedial approaches for arthroscopic manipulation;Anatomical relationship of three different anteromedial approaches to median nerve and ulnar nerve at 90 degree elbow flexion was measured on the same specimen,to investigate the safety of three different anteromedial approaches.objective:To investigate the size of field of vision,the difficulty of arthroscopy and the flexibility of operation through three different anteromedial approaches;to investigate the anatomical relationship of median nerve and ulnar nerve with three different anteromedial approaches of elbow arthroscopy at 90degree elbow flexion.Methods:Ten fresh thawed cadavers of elbow joints were selected,including 8 males,2 females,6 left and 4 right.They were aged 18-74 years.There were no deformities and no history of surgical trauma.Application of arthroscopic system,surgical anatomical instruments and measuring tools:vernier calipers?accurate to 0.02 mm?.First of all,the bony surface markers were carefully touched at 90 degree elbow flexion.Marker pens were used to mark the internal and external epicondyles of humerus,olecroon,humerus and the axis of ulna.Proximal anterolateral approach and anterolateral approach A,B and C were respectively marked.Through the soft point approach?located between the external epicondyle of the humerus,the olecranon,and the radial capitulum?,15-25 ml saline was injected into the elbow cavity to expand the elbow joint,so as to keep the nerve vessels away from the center of the joint cavity.Water injection cannot be too little,insufficient water injection,joint capsule cannot be fully expanded;too much water is easy to destroy the joint capsule,resulting in water leakage into the surrounding tissue gap,soft tissue swelling,resulting in the collapse of the joint capsule,resulting in the increase of measurement data error.The proximal anterolateral approach?2 cm proximal to the lateral epicondyle of the humerus and 1 cm anterior?was established as an observational approach.A 4 mm incision was made with a sharp knife.The subcutaneous tissue and fascia were separated bluntly by a straight vascular clamp.After penetrating the synovium,then entered the articular cavity.Insert the arthroscope under the protection of the working cannula and open the saline intake pipe.Suspend the 3L bag of saline at a height of 2 meters to maintain the joint cavity pressure.The proximal anterolateral approach was used as the observation approach,and the anterolateral approach A,B and C were established successively from outside to inside by using exchange rod technique under arthroscopy?Fig.3?.Three different anteromedial approaches?approach A:distal end of medial epicondyle of humerus 2 cm,anterior 2 cm;approach B:distal end of medial epicondyle of humerus 1 cm,anterior 1 cm;approach C:distal end of medial epicondyle of humerus 2 cm,anterior 1 cm?were observed.After arthroscopic observation,elbow joint flexion was 90degrees.Three Kirschner needles of 4.0 mm diameter?Due to the lack of enough puncture cones,three kirschner needles with the same diameter were used instead in this experiment.?were punctured through three anteromedial approaches to the center of elbow joint cavity.The assistant kept the direction and position of the Kirschner needle,dissected the elbow joint specimens,removed the skin and subcutaneous tissue around the three approaches,and separated the median nerve and ulnar nerve.The nearest vertical distance between Kirschner's needle and median nerve and ulnar nerve was marked with empty needle needle.The measured results were recorded with vernier caliper?Fig.10,11?.At present,domestic and foreign literatures have confirmed that the 90 degree elbow flexion surgical approach is farther and safer from median nerve and ulnar nerve than straight.⁵-7-7 Therefore,this study did not include the comparison of the distance between the 90 degree flexion and the extension of the anteromedial elbow arthroscopic approach.Usually,the arteriovenous is anterior to the elbow and lateral to the median nerve.Therefore,the distance between the anteromedial approach and the arteriovenous was not measured in this study.In clinical operation,the cutaneous nerve is not easily damaged by penetrating the skin with a sharp knife and bluntly separating subcutaneous tissue and fascia with a straight vascular clamp.Therefore,the nearest distance between anteromedial approach and cutaneous nerve was not measured.In this study,the nearest vertical distances of median nerve and ulnar nerve from three different anteromedial approaches to elbow arthroscope at 90 degrees of elbow flexion were measured.Results:Arthroscopic anteromedial approach A revealed most of the capitulum radii,most of the coronoid processes of the ulna and all of the coronoid fossa.During forearm rotation,the observation range of the radial head can be increased.About 75%of the radial head can be seen,and the observation field is wide.Anteromedial approach A has a good visual field in observing the lateral compartment of elbow joint and the proximal articular capsule insertion area,which was basically consistent with Steinmann[8].Most coronoid processes of ulna,a small part of the radial capitulum and all coronoid fossa can be seen in anteromedial approach B.The visual field of humerus-ulnar joint is relatively good,but the visual field of humerus-radial joint is poor.Rotating arthroscopy can clearly show the medial capitulum of humerus and the medial anterior articular capsule.The anteromedial approach C showed most of the radial capitulum and most of the coronoid process and coronoid fossa of the ulna.The anterior articular cavity of the lateral compartment of the elbow joint and the distal articular capsule insertion area were well observed,and the field of vision was acceptable.All three approaches are easy to establish without significant difference.Among the three approaches,approach A has the broadest visual field and the most flexible operation,followed by approach C,and approach B has a smaller visual field and relatively poor operational flexibility.The closest distances between the median nerve and ulnar nerve through three different anteromedial approaches?see table for details?.The nearest distances of A,B and C from median nerve in 90 degree flexion of elbow joint were?8.82±1.98?mm,?15.92±1.40?mm,?13.91±1.39?mm?F=33.128,P<0.001?,respectively.There were statistical differences among the three groups.There were significant differences between approach A and B(P_A-B<0.001),and between approach A and C(P_A-C<0.001).There was no significant difference between approach B and approach C(P_B-C=0.183).Therefore,the anteromedial approach A is the closest to the median nerve.The proximal distances of A,B and C from ulnar nerve nerve in 90 degree flexion of elbow joint were?25.14±2.52?mm,?17.59±1.73?mm,?22.37±1.82?mm?F=37.376,P<0.001?,respectively.There were statistical differences among the three groups.There were significant differences between the three approaches(P_A-B<0.001,P_B-C<0.001,P_A-C=0.006).Therefore,anteromedial approach B is the closest to the ulnar nerve and approach A is the farthest from the ulnar nerve.Conclusion:?1?.The anteromedial approach is 2 cm distal to the medial epicondyle of the humerus and 2 cm anterior to the condyle.It has a wide field of vision and the most flexible operation.However,the nearest to the median nerve,the highest risk of nerve injury,the choice of this approach to pay attention to the protection of the median nerve.?2?.The anteromedial approach is2 cm distal to the medial epicondyle of the humerus and 1 cm anterior to it.The scope of visual field under the microscope is available,the operation is flexible,the nerve injury is small,and it is relatively safe.This approach is recommended for clinical operation.?3?.The anteromedial approach is located at the distal end of the medial epicondyle of humerus 1 cm and anterior 1 cm.It has a small field of vision and poor flexibility in operation.But far from the median nerve,the risk of nerve injury in clinical operation is small and relatively safe.?4?.Less risk of ulnar nerve injury through anteromedial approach of elbow arthroscopy at 90 degrees of elbow flexion.