Quantifying the Location of the Radial Nerve in Children for Intraoperative Use

Flexible Intramedullary Nail Placement in Pediatric Humerus Fractures

Background

Flexible intramedullary nailing is an effective method of stabilization in pediatric patients with a humeral shaft fracture when surgery is indicated1-3. Although these fractures are most often treated nonoperatively, operative indications include open fractures, bilateral injuries, compartment syndrome, pathologic fractures, neurovascular compromise, unacceptable alignment after attempted nonoperative treatment, and ipsilateral upper-extremity injuries4. The current literature on flexible intramedullary nailing of the pediatric humeral shaft lacks concise descriptions of available entry points, which directly affect the subsequent technique, and of pertinent pediatric-specific anatomy. Thus, the present article focuses on these entry points in the pediatric patient.

Description

Various entry points are available for the insertion of flexible nails into the humeral shaft. A surgeon must initially decide whether the patient and fracture characteristics are best suited for anterograde versus retrograde insertion. This choice typically depends on several fracture and patient-related characteristics. The passage of flexible intramedullary nails has been well described; thus, the present article will place special emphasis on the available proximal and distal entry points and pediatric-specific anatomy5-10. For diaphyseal fractures, we prefer dual distal lateral entry points with the nails advanced retrograde in a C-S configuration whenever possible, given the risks associated with proximal lateral entry (e.g., damage to the axillary nerve) or distal medial entry (e.g., damage to the ulnar nerve or nail prominence). A distal posterior supracondylar entry point is also possible but requires additional preoperative planning with regard to patient positioning, a more proximal entry point to avoid impingement of the olecranon on the nail in extension, and avoidance of the ulnar nerve.

Alternatives

The substantial potential for remodeling in pediatric patients permits nonoperative treatment of humeral fractures if specific age-related criteria for angulation and displacement are met. Generally accepted tolerances for nonoperative angulation and displacement are as follows: for patients <5 years old, ≤70° angulation and up to 100% displacement; for patients 5 to 12 years old, 40° to 70° angulation; and for patients >12 years old, ≤40° angulation and 50% apposition4.

Rationale

The use of flexible nails is often preferred because of the healing potential of pediatric humeral shaft fractures, the ability of flexible nails to tolerate nonrigid fixation until osseous bridging occurs, the ability of the surgeon to avoid exposure of neurologic structures during surgery, and the benefit of avoiding physeal disruption. These factors make flexible nails a favorable option when compared with plate osteosynthesis or rigid intramedullary nailing.

Expected Outcomes

When indicated, the use of flexible intramedullary nails in pediatric humeral fractures has been associated with high rates of union, good functional outcomes, early range of motion, and an acceptably low rate of complications2.

Important Tips

Be familiar with the technical details associated with all available entry points.Avoid damage to key neurologic structures around the proximal and distal humerus.Minimize the opportunity for symptomatic hardware.Optimize the biomechanics through flexible nail positioning at the fracture site.

Acronyms and Abbreviations

FIN = flexible intramedullary nailingEBL = estimated blood lossf/u = follow-upIM = intramedullaryMRI = magnetic resonance imagingOR = operating roomPT = physical therapyROM = range of motion.

Dual Joystick Technique for Reduction of Torsional Profile in Pediatric Supracondylar Humerus Fracture With Delayed Presentation

BACKGROUND

Reduction of some modified Gartland type III and IV supracondylar humerus fractures can pose difficulties, especially if they present late to the hospital. Various techniques of reduction have been tried for reducing the supracondylar humerus fracture for sagittal and coronal plane correction. This retrospective study assesses the dual joystick technique's possible effectiveness in achieving an anatomical reduction of the supracondylar humerus fracture.

METHODS

Patients with modified Gartland's type III and IV supracondylar humerus fractures who underwent closed reduction and percutaneous pinning using the dual joystick technique at our trauma center between January 2020 and January 2022 were the subject of a retrospective review. Forty-six patients treated by the above technique who met the inclusion criteria were analyzed at the end of the final follow-up.

RESULTS

The mean age of the children was 7.9+/- 2.25 years, with a male predominance at 32:14. The Right upper limb was more involved compared to the left side. The mean injury to hospital presentation was 2.67+/- 1.28 days, and the mean surgical duration was 24.57+/- 13.76 minutes. The average pin spread ratio at the fracture site was 35.17+/- 3.04%. Baumann angle at the final follow-up was 74.83+/- 2.56 degrees. The mean lateral rotation percentage was 2.8+/- 1.3%. 39 patients had excellent cosmetic outcomes, and 42 had excellent functional outcomes, whereas 7 and 4 patients had good cosmetic and functional outcomes, respectively, according to Flynn criteria.

CONCLUSIONS

In modified Gartland type III and IV fractures with late presentation where reduction is challenging, this technique is shown to be convenient and easily reproducible and helps accomplish near anatomical reduction with reduced lateral rotation percentage and results in excellent to good outcomes.

Vascular Safe Zone During Percutaneous Pinning of the Distal Femur

PURPOSE

During percutaneous pinning of the pediatric distal femur, iatrogenic vascular damage in the medial thigh is a frequent concern. The proximity of a proximal-medial pin to these vessels has never been studied in children. This study describes a radiologic vascular safe zone that is easily visualized during surgery (wherein the superficial femoral vessels are safely posterior).

METHODS

Patients ≤16 years old with magnetic resonance imaging of one or both femora between 2005 and 2020 were retrospectively reviewed. The "at-risk level" (ARL) was defined as the distal-most axial image with a femoral vessel anterior to the posterior condylar axis. A standardized retrograde lateral-to-medial pin was templated. A correlation matrix and least squares regression identified age and physeal width (PW) as ideal independent variables. A vascular safe zone above the medial femoral condyle (MFC) was modeled as a multiple of PW (i.e. x*PW) and needed to satisfy 3 age-dependent criteria: (1) at the ARL, the pin is medial to the vessels, (2) the pin exits the medial thigh before the ARL, and (3) the chosen "vascular safe zone" (x*PW) is always distal to the ARL.

RESULTS

Forty-three patients averaging 7.1±3.9 (0.3-16) years old were included. Intra-Class correlation coefficients were excellent (0.92-0.98). All measurements strongly correlated with age ( r =0.76-0.92, P <0.001) and PW ( r =0.82-0.93, P <0.001). All patients satisfied criteria 1. Criteria 2 was satisfied in all patients ≥6 years old, 86% of children 4-5, and only 18% of children ≤3. In children >3 years old, the largest safe zone that satisfied criteria 3 was 2×PW. On average, the ARL was 2.5×PW (99% CI 2.3-2.7) above the MFC. The average ARL in children ≥6 years old was significantly higher than 2×PW (162 mm vs. 120 mm, P <0.001).

CONCLUSION

During passage of a distal femur pin into the medial thigh, children ≥6 years old have a vascular safe zone that extends 2×PW proximal to the MFC. Surgeons should be cautious with medial pin placement in children 4-5 years old and, if possible, avoid this technique in children ≤3.

LEVEL OF EVIDENCE

IV.

Oblique Lateral Closing-Wedge Osteotomy for Cubitus Varus in Skeletally Immature Patients

Background

We perform an oblique lateral closing-wedge osteotomy of the distal end of the humerus to correct cubitus varus deformity in children. This deformity is often the consequence of undertreatment, malreduction, or malunion of supracondylar humeral fractures¹. Although standard arcs of motion may be altered, cosmesis was traditionally considered a primary surgical indication. However, uncorrected cubitus varus leads to posterolateral rotatory instability of the elbow (PLRI)², lateral condylar fractures³, snapping medial triceps, and ulnar nerve instability⁴. A contemporary understanding of these delayed sequelae has expanded our current indications. Detailed parameters predictive of late sequelae are needed to further specify surgical indications.

Description

We remove an oblique lateral closing wedge from the distal end of the humerus via a standard lateral approach. The osteotomy is angled away from the varus joint line such that lateral cortices after reduction lack prominence. Kirschner wires provide adequate fixation in young patients. In older children, extension is simultaneously corrected, and fragments are stabilized via plate osteosynthesis.

Alternatives

Patients who decline surgery are counseled regarding risks of delaying treatment until symptoms are present. PLRI manifests as lateral elbow pain or instability while rising from a chair. Once symptomatic, the lateral ulnar collateral ligament (LUCL) is irreversibly attenuated and morphologic changes in the ulnohumeral joint necessitate more extensive surgery to include distal humeral osteotomy, LUCL reconstruction, and possibly ulnar nerve transposition⁵. Alternative osteotomy techniques are described and categorized as simple lateral closing wedge, step-cut^6-9, dome, 3-dimensional¹⁰, or distraction osteogenesis. Simple closing-wedge osteotomies include a distal cut parallel to the joint line and retain a problematic lateral prominence (if the medial cortex is intact or the distal end of the humerus is not translated medially)^11,12. Step-cut osteotomies theoretically minimize this lateral prominence while enhancing inherent stability. However, these additional cuts mandate wide surgical exposure despite similar outcomes¹³. Three-dimensional planning employs computed tomography to create expensive anatomic cutting guides that address varus, extension, and internal rotation. However, residual internal rotation is generally well tolerated, derotation is associated with loss of fixation, and the extension deformity will successfully remodel in patients who are <10 years old¹⁴. We employ 3-dimensional planning in skeletally mature patients with complex deformity and no remodeling potential.

Rationale

The oblique lateral closing wedge is ideal for skeletally immature patients because it is simple, reproducible, and efficient. It avoids the lateral prominence without increasing complexity or complications.