A Mini-Open Approach to Medial Pinning in Pediatric Supracondylar Humeral Fractures May Be Safer Than Previously Thought

Abstract

Background: Displaced pediatric supracondylar humeral fractures (SCHFs) are stabilized after reduction by smooth pins. Although some SCHFs are biomechanically stable after lateral-only entry pinning (lateral pinning), an additional medial entry pin (cross-pinning) confers superior stabilization in some SCHFs. There is a recognized risk of iatrogenic ulnar nerve injury with medial entry pinning. The best existing evidence has estimated an iatrogenic ulnar nerve injury rate of approximately 3.4% in cross-pinning. In similar studies, the rate of iatrogenic nerve injury (all nerves) in lateral pinning is estimated at 1.9%. This study aimed to use a large, single-center, single-technique (mini-open) retrospective case series to determine the rate of iatrogenic ulnar nerve injury in cross-pinning.Methods: Patients undergoing percutaneous cross-pinning via the mini-open technique for SCHFs from 2007 to 2017 were retrospectively reviewed. Injury characteristics, operative variables, fixation technique, and complications, such as iatrogenic nerve injury, were recorded. Patients who underwent operative treatment at another hospital, had no postoperative follow-up, or died due to polytrauma were excluded.Results: In this study, 698 patients undergoing cross-pinning during the study period were identified. Patients treated with cross-pinning had severe fractures, including a total of 198 preoperative neurovascular injuries (28.4%), 32 patients (4.6%) with skin tenting, and 19 patients (2.7%) with open fractures. Iatrogenic nerve injury was reported in 3 cases (0.43%), all of which affected the ulnar nerve. In 2 of 3 cases of iatrogenic nerve injury, the ulnar nerve symptoms resolved at a mean follow-up of 15 weeks. Conclusions:The mini-open approach for medial pin insertion is safer than previous estimates. Here, in the largest single-center study of cross-pinning for SCHFs, the iatrogenic ulnar nerve injury rate of 0.43% was nearly 10 times lower than estimated rates from recent meta-analyses. Considering all nerves, the iatrogenic injury rate for this cross-pinning cohort was also lower than the estimated iatrogenic nerve injury rate for lateral pinning.

Management of iatrogenic ulnar nerve palsies after cross pinning of pediatric supracondylar humerus fractures: A systematic review

“…In these future studies, results that need to be reported should include: (a) A clear distinction between acute iatrogenic ulnar nerve injury (motor and sensory loss) and iatrogenic ulnar nerve impingement or irritation (sensory change) because of their very different clinical consequences. 4 (b) Timing to detection and management of the ulnar nerve palsy including time to removal of the medial wire and/or exploration. (c) Findings at surgical exploration. (d) Other complications such as loss of reduction. (e) Detailed clinical recovery at final follow-up. …”

“…Of those who had early intervention, 4 (15.4% of the exposure group) did not fully recover at final follow-up. These data came from 2 papers, 4 , 10 and due to the very low numbers and heterogeneity of the data, no statistics could be applied.…”

“…(a) A clear distinction between acute iatrogenic ulnar nerve injury (motor and sensory loss) and iatrogenic ulnar nerve impingement or irritation (sensory change) because of their very different clinical consequences. 4 …”

“…Of the explored nerves, there were no divided nerves requiring repair or grafting. 16 1 6 weeks Unclear N 17 1 3 weeks Unclear; within 3 months N 19 3 4-6 weeks 6.7 months (mean) N 20 2 3 weeks 3 months N 21 2 4-6 weeks Unclear N 22 1 3 weeks 1 month N 6 23 4-6 weeks 6 months N 23 2 3.5 weeks 3 months N 24 11 3-4 weeks 4.5 months N 25 4 3 weeks 3 months Y 4 2 3 weeks 4 months N 27 5 3-4 weeks 7 months (mean) N 7 2 3-4 weeks 6 months (mean) N 28 3 3 weeks Unclear N 29 17 'once fracture healed' 6 months (mean) N 31 4 4 weeks 3.5 months (mean) N 32 52 3-4 weeks 2.5 months (mean)…”

“… 1 This is decreased to 0.4%–1.8% if a mini-open approach is used for the medial wire. 2 , 4 There is no consensus how to treat these iatrogenic nerve palsies. Some authors advocate treatment of the fracture without early intervention; 5 , 6 others advocate for early wire removal or repositioning 7 , 8 and/or early exploration of the ulnar nerve.…”