Computer-Assisted Surgical Anatomical Mapping of the Antebrachial Cutaneous Nerves: An Anatomical Study with a Proposition for Alternative, Cutaneous Nerve-Sparing Anterior Elbow Incisions.

It is common practice to assess the distance from nerves to anatomical structures in centimeters, but patients have various body compositions and anatomical variations are common. The purpose of this study was therefore to assess the relative distance from cutaneous nerves around the elbow to surrounding anatomical landmarks by providing a stacked image that displays the average position of cutaneous nerves around the elbow. The aim was to research possibilities for adjusting common skin incisions in the anterior elbow so that cutaneous nerve injury may be avoided. Methods: The lateral antebrachial cutaneous nerve (LABCN) and medial antebrachial cutaneous nerve (MABCN) were identified in the coronal plane around the elbow joint in 10 fresh-frozen human arm specimens. Marked photographs of the specimens were analyzed using computer-assisted surgical anatomical mapping (CASAM). Common anterior surgical approaches to the elbow joint and the distal humerus were then compared with merged images, and nerve-sparing alternatives are proposed. Results: The arm was divided longitudinally, from medial to lateral in the coronal plane, into 4 quarters. The LABCN crossed the central-lateral quarter of the interepicondylar line (i.e., was somewhat lateral to the midline at the level of the elbow crease) in 9 of 10 specimens. The MABCN ran medial to the basilic vein and crossed the most medial quarter of the interepicondylar line. Thus, 2 of the quarters were either free of cutaneous nerves (the most lateral quarter) or contained a distal cutaneous branch in only 1 of 10 specimens (the central-medial quarter). Conclusions: The Boyd-Anderson approach, which is often used to access anteromedial structures of the elbow, should be placed slightly further medially than traditionally advised. The distal part of the Henry approach should deviate laterally, so that it runs over the mobile wad. In distal biceps tendon surgery, the risk of cutaneous nerve injury may be reduced if a single distal incision is placed slightly more laterally (in the most lateral quarter), as in the modified Henry approach. If proximal extension is required, LABCN injury may be prevented by using the modified Boyd-Anderson incision, which runs in the central-medial quarter. Clinical Relevance: Cutaneous nerve injury may be prevented by slightly altering the commonly used skin incisions around the elbow on the basis of the safe zones that were identified by depicting the cumulative course of the MABCN and LABCN using CASAM.

Safe approach for fixation of first metacarpal fractures: an anatomical study.

This anatomical study defines a safe zone for percutaneous or minimally invasive fixation of first metacarpal fractures in order to avoid injury of the superficial branch of the radial nerve and the dorsal branch of the radial artery. The courses of the nerve and artery branches were marked in 20 embalmed cadaver specimens. With computer-assisted surgical anatomy mapping, a large diversity in the anatomical patterns for the nerve and a consistent pattern for the artery were found. Based on these findings, we conclude that transfixation of the first and the second metacarpals with K-wires placed in the distal 75% of both the first and second metacarpals is the safest way to avoid damages to the nerve and artery branches during fracture fixation.

Optimal surgical approach for the treatment of Quervains disease: A surgical-anatomical study.

AIM: To determine which of the common used incision techniques has the lowest chance of iatrogenic damage to the nerves which at risk are the superficial branch of the radial nerve (SBRN) and the Lateral Antebrachial Cutaneous Nerve (LABCN). METHODS: Twenty embalmed arms were dissected and the course of the SBRN and the LABCN in each individual arm was marked and the distance between the two branches of the SBRN at the location of the First Extensor Compartment (FEC) was measured. This data was used as input in a visualization tool called Computer Assisted Anatomy Mapping (CASAM) to map the course of the nerves in each individual arm. RESULTS: This image visualizes that in 90% of the arms, one branch of the SBRN crosses the FEC and one branch runs volar to the compartment. The distance between the two branches was 7.8 mm at the beginning of the FEC and 10.2 mm at the end. Finally the angle of incision at which the chance of damage to the nerves is lowest, is 19.4 degrees volar to the radius. CONCLUSION: CASAM shows the complexity of the course of the SBRN over the FEC. None of the four widely used incision techniques has a significantly lower chance of iatrogenic nerve damage. Surgical skills are paramount to prevent iatrogenic nerve damage.

Unilateral fusion of the scaphoid and the trapezium.

Fusion of the carpal bones is a rare anatomical abnormality, caused by a defect in the separation and cavitation during embryonic development. It has a prevalence of about 0.1% and most of the time, patients do not present with symptoms. Symptoms are usually caused by wear and tear of the ligaments attached to the fused carpal fragments. We present a case in which a woman aged 36 years experiences pain caused by a lunato-triquetral instability which in turn is caused by a unilateral complete fusion of the scaphoid and the trapezium. A unilateral complete fusion of the scaphoid and trapezium has not been reported before.