Safe Zone for Superolateral Entry Pin Into the Distal Humerus in Children: An MRI Analysis (original) (raw)
PLOS ONE
Iatrogenic nerve injury during fracture surgery of the upper arm is a well-known complication. Prevention of this type of injuries would be of great value. The literature describes several methods to reduce this type of injury, but no perfect solution is at hand. In this study we introduce a new radiographic evaluation of the course and variation of the radial nerve in the distal part of the humerus in relation to bony landmarks as observed on a plain (trauma) radiographs. Aim of this new approach is to reduce the chance of iatrogenic nerve injury by defining of a danger zone in the distal upper arm regarding the radial nerve and hence give an advise for future implant fabrication. Methods and findings Measurements were done on both arms of ten specially embalmed specimens. Arms were dissected and radiopaque wires attached to the radial nerve in the distal part of the upper arm. Digital radiographs were obtained to determine the course of the radial nerve in the distal 20 cm of the humerus in relation to bony landmarks; medial epicondyle and capitellumtrochlea projection (CCT). Analysis was done with ImageJ and Microsoft Excel software. We also compared humeral nail specifications from different companies with the course of the radial nerve to predict possible radial nerve damage. Results The distance from the medial epicondyle to point where the radial nerve bends from posterior to lateral was 142 mm on AP radiographs and 152 mm measured on the lateral radiographs. The average distance from the medial epicondyle to point where the radial nerve bends from lateral to anterior on AP radiographs was 66 mm. On the lateral radiographs where the nerve moves away from the anterior cortex 83 mm to the center of capitellum and
Clinical Anatomy, 2009
The percutaneous placement of lateral distal humeral pins risks injury to the radial nerve. We aimed to provide a reliable and safe parameter for the insertion of lateral distal humeral pins. A secondary aim of this study was to investigate the effect of pin/screw placement in the intended zone of fixation at the lateral distal humerus. We dissected 70 fresh cadaveric upper limbs and the radial nerve was identified and its course followed into the anterior compartment. The point where the radial nerve crosses humerus in mid lateral plane was identified and the distance between this point and lateral epicondyle was measured, as was the maximum trans-epicondylar distance, along with the olecranon fossa height. Statistical analysis was performed using the Pearson correlation coefficient. The average trans-epicondylar distance was measured at 62 ± 6 mm (range 52–78 mm), and the average lateral radial nerve height was 102 ± 10 mm (range 75–129 mm). The ratio of the lateral nerve height to the trans-epicondylar distance was an average of 1.7 ± 0.2 (range 1.4–2.0). The Pearson correlation coefficient between the lateral nerve height and the trans-epicondylar distance was r = 0.95. A relative dimension, the trans-epicondylar distance is both reliable and easily accessible to the operating surgeon. The absolute safe zone for pin entry into the lateral distal humerus is that area lying within the caudad 70% of a line, equivalent in length to the patient's own trans-epicondylar distance, when projected proximally from the lateral epicondyle. Clin. Anat. 22:684–688, 2009. © 2009 Wiley-Liss, Inc.
The location of the radial nerve (RN) is described with various bony landmarks, but such may be disturbed in the setting of fracture and dislocation of bone. Alternative soft tissue landmarks would be helpful to locate the nerve in such setting. To recognize certain anatomic landmarks to identify, locate and protect RN from any iatrogenic injury during surgical intervention such as open reduction and internal fixation. Forty arms belonging to 20 adult cadavers were used for this study. We measured the distance of RN from the point of confluence of triceps aponeurosis (TA), tip of the acromion and tip of the lateral epicondyle along the long axis of the humerus. These distances were correlated with the upper arm length (UAL). The average UAL was 32.64±0.64 cm. The distance of the RN from the point of confluence of TA (tricepso-radial distance, TRD), tip of acromion (acromion-radial distance) and tip of lateral epicondyle of humerus (condylo-radial distance, CRD) was 3.59±0.16 cm, 14.27±0.59 cm, and 17.14±1.29 cm respectively. No correlation was found with UAL. Statistically, TRD showed the least variability and CRD showed maximum variability. The minimum TRD was found to be 3.00 cm. So this should be considered as the maximum permissible length of the triceps split. The point of confluence of the TA appears to be the most stable and reliable anatomic landmark for localization of the RN during the posterior approach to the humerus.
Establishing Safe Zones to Avoid Nerve Injury in the Approach to the Humerus in Pediatric Patients
Journal of Bone and Joint Surgery, 2019
Background: The surgical anatomy of upper-extremity peripheral nerves in adults has been well described as "safe zones" or specific distances from osseous landmarks. In pediatrics, relationships between nerves and osseous landmarks remain ambiguous. The goal of our study was to develop a model to accurately predict the location of the radial and axillary nerves in children to avoid iatrogenic injury when approaching the humerus in this population. Methods: We conducted a retrospective review of 116 magnetic resonance imaging (MRI) scans of entire humeri of skeletally immature patients; 53 of these studies met our inclusion criteria. Two independent observers reviewed all scans. Arm length was measured as the distance between the lateral aspect of the acromion and the lateral epicondyle. We then calculated the distances (defined as the percentage of arm length) between the radial nerve and distal osseous landmarks (the medial epicondyle, transepicondylar line, and lateral epicondyle) as well between the axillary nerve and the most lateral aspect of the acromion. Results: The axillary nerve was identified at a distance equaling 18.6% (95% confidence interval [CI], ±0.62%) of arm length inferior to the lateral edge of the acromion. The radial nerve crossed (1) the medial cortex of the posterior part of the humerus at a distance equaling 63.19% (95% CI: ±0.942%) of arm length proximal to the medial epicondyle, (2) the middle of the posterior part of the humerus at a distance equaling 53.9% (95% CI: ±1.08%) of arm length proximal to the transepicondylar line, (3) the lateral cortex of the posterior part of the humerus at a distance equaling 45% (95% CI: ±0.99%) of arm length proximal to the lateral epicondyle, and (4) from the posterior to the anterior compartment at a distance equaling 35.3% (95% CI: ±0.92%) of arm length proximal to the lateral epicondyle. A strong linear relationship between these distances and arm length was observed, with an intraclass correlation coefficient of >0.9 across all measurements. Conclusions: The positions of the radial and axillary nerves maintain linear relationships with arm lengths in growing children. The locations of these nerves in relation to palpable osseous landmarks are predictable. Clinical Relevance: Knowing the locations of upper-extremity peripheral nerves as a proportion of arm length in skeletally immature patients may help to avoid iatrogenic injuries during surgical approaches to the humerus. A confident surgeon has an intimate understanding of applied anatomy and an excellent knowledge of anatomic relationships. Avoiding iatrogenic injury is critically important. Hence, various publications have described "safe zones" and reference distances from anatomic landmarks 1. These points of reference help surgeons anticipate the positions of critical structures such as nerves before they are encountered, thereby reducing the chance of iatrogenic injury 2-4. The surgical anatomy of peripheral nerves in the upper extremity has been well described in adults 5. Fleming et al. described the "one-third, two-thirds rule" to reliably identify the radial nerve as it crosses from the posterior to the anterior compartment of the upper arm 6. Uhl et al. established the 13-cm rule to avoid iatrogenic radial nerve injury when approaching the humerus posteriorly 7. Cetik et al. elucidated a "safe zone" for the axillary nerve when approaching the proximal part of the humerus through a deltoid-split approach 8. These rules simplify complex anatomy and can be easily committed to memory to avoid iatrogenic nerve injury and increase patient safety 9 .
Surgical anatomy of the radial nerve at the elbow
Surgical and Radiologic Anatomy, 2009
An anatomical study of the brachial portion of the radial nerve with surgical implications is proposed. Thirty specimens of arm from 20 fresh cadavers (11 male, 9 female) were used to examine the topographical relations of the radial nerve with reference to the following anatomical landmarks: acromion angle, medial and lateral epicondyles, point of division between the lateral and long heads of the triceps brachii, lateral intermuscular septum, site of division of the radial nerve into its superWcial and posterior interosseous branches and entry and exit point of the posterior interosseous branch into the supinator muscle. The mean distances between the acromion angle and the medial and lateral levels of crossing the posterior aspect of the humerus were 109 ( §11) and 157 ( §11) mm, respectively.
International Journal of Orthopaedics Sciences, 2021
Background: The radial nerve arises from posterior cord of brachial plexus and descends distally to spiral groove, our aim is to study upper and lower margins of groove with respect of bony landmark like posterolateral aspect of Acromian process, medial and lateral epicondyle of humerus, which helps to identify radial nerve during humerus fracture fixation surgery and hence will reduce iatrogenic radial nerve injury. Methods: Twenty formalin preserved cadaveric upper limbs obtained from anatomy department of Government medial collage, Surat. Dissection done, Radial nerve isolated from low triangular space to lateral inter muscular septum and various measurements done for each specimen. Result: Without sex or age differentiation the results of this study are: The mean humeral length was 30.6 ± 1.86 cm. Mean Distance of medial epicondyle to entry of radial nerve into spiral groove was 18.3±1.48 cm. Mean Distance of lateral epicondyle to exit of radial nerve into spiral groove was 11.4...
Zagazig university medical journal, 2015
The radial nerve is one of the most commonly injured nerves in long bone fractures. Knowledge of the anatomy of the radial nerve is a key component for safety and successful surgical procedures about the arm and the elbow. This study aimed to identify the level of the points at which the radial nerve begins and ends its course on the posterior shaft of humerus in relation to the palpable anatomic bony landmarks of the arm. The upper limbs of twenty adult human cadavers, ten males and ten females, were used in this study. The specimens were obtained from the Anatomy Department, Faculty of Medicine, King Abdul Aziz University. The limbs were dissected and the radial nerve of each was exposed throughout its course within the arm. The distance between the points of both radial nerve entry and exit on the spiral groove was measured in relation to different bony landmarks. The values were measured in millimeters and in percentages in relation to the humeral length. The average humeral length (from the postero lateral angle of acromion to the centre of lateral epicondyle) was 316 mm ± 5.5 in male upper limbs and 286 mm ± 15.4 in female upper limbs. The mean distance from the point of radial nerve entry to the lateral angle of acromion, tip of the coracoid process, centre of lateral and medial epicondyles was 143.3 ± 14 mm (44.5%), 131.7 ± 14.9 mm (42.5%), 174.2 ±13.3 mm (55.5%) and 178.1± 15.2 mm(57.5%) in male upper limbs and they were 121.4 ± 10.4 mm (42.4%), 116.6 ± 12.3 mm (41.4%), 164.6 ± 1.9 mm (57.6%) & 166.3 ± 13.2 mm (58.6%) in female upper limbs respectively. However, the mean distances from the point of radial nerve exit to same bony landmarks were 214.2 ± 12.4 mm (67.7%), 205.6 ± 13.2 mm (66.4%), 102.5 ± 12.9 mm (32.3%), 104.7 ± 13 mm (33.8%) in male upper limbs and were 185.3 ± 14.6 mm(64.8%), 180.9 ± 13.4 mm (64.8%), 100.3 ± 8 mm (35.1%), 101.3 ± 7 mm (36%) and 23.8 ± 6 mm (8%) in female upper limbs respectively. Significant differences (P < 0.01) were reported between most of radial nerve measurements of both male and female upper limbs with exception of the mean distance from the point of radial nerve exit to the centre of both lateral and medial epicondyles. However, no significant differences were recorded between the measurements of right and left upper limbs of male or female cadavers. The palpable bony landmarks of arm provide an accurate data for the surgeon to determine the location and to avoid the iatrogenic injury of the radial nerve during the surgical interventions of the arm.
Arthroscopy : the journal of arthroscopic & related surgery : official publication of the Arthroscopy Association of North America and the International Arthroscopy Association, 2018
To provide a quantitative and qualitative anatomic analysis of the pectoralis major, teres major, and latissimus dorsi on the humerus, as well as the deltoid tendinous attachments on the proximal humerus and acromion, and to quantitatively characterize the humeral course of the axillary nerve. Ten nonpaired, fresh-frozen human cadaveric shoulders were analyzed. A portable coordinate-measuring device quantified the location of bony landmarks and tendon attachment areas. The tendon footprints were recorded by tracing their outlines and center points. The footprint areas of the tendons, the distances between the footprint areas and pertinent osseous and soft-tissue landmarks, and the distance between where the axillary nerve courses across the humerus relative to the acromion and greater tuberosity were measured. Of the 10 specimens, 9 (90%) had 5 distinct tendinous bands attaching the deltoid to the acromion; 1 specimen had 4 bands. The distances between the center of the deltoid foot...