Anatomical Considerations of Intramedullary Humeral Nailing and Lengthening

The Use of Photodynamic Bone Stabilization to Tamponade Bleeding in a Pathologic Humeral Shaft Fracture: A Case Report

Introduction

Hypervascular tumors such as renal and thyroid carcinoma have a significant risk of intraoperative bleeding. To help mitigate bleeding, interventional preoperative embolization is traditionally used; however, it is success is highly variable. This is the first case report to discuss using expandable balloon implants with a minimally invasive approach to achieve fracture fixation and tamponade acute intraoperative bleeding.

Case Report

A 48-year-old male with clear-cell renal cell carcinoma presented with a left humeral shaft pathologic fracture. The patient was scheduled to undergo open biopsy, curettage of tumor, and fracture fixation with an intramedullary device. Intraoperatively, during open biopsy and curettage, brisk bleeding was encountered, which ceased after inserting an intramedullary photodynamic bone stabilization implant (IlluminOss). The implant's balloon expanded to the diameter of the humerus allowing for tamponade, fracture stability, and a minimally invasive approach.

Conclusion

We present a possible intraoperative option for achieving control of bleeding in pathologic long bone fractures by deploying a photodynamic stabilization device. The method described can have applications in specific patients and obviate the need for pre-operative embolization for highly vascular tumors due to the implant's ability to create tamponade within the bone.

The Impact of Supratrochlear Foramen on Humeri's Medullary Canal Diameter and Its Surgical Implications

Introduction Supracondylar elbow fractures are prevalent in the pediatric age group, and retrograde intramedullary nailing of the humerus is a common treatment approach. The anatomy of the medullary canal and the presence of the supratrochlear foramen (STF) significantly influence the stabilization of the nail. This study aimed to determine the incidence and morphology of the STF and compare the width of the medullary canal in humeri with and without the STF. Methods We examined 40 humeri bones with fused humeral epiphyses for the presence of the STF obtained from the Department of Anatomy's osteology collections. We studied the morphology and measured the dimensions of the foramen. We then compared the morphometric characteristics of humeri bearing the STF with those without it. We also took radiographs of all bones and measured the medullary canal width at three levels. We compared the measured width of the medullary canal in humeri between those with an STF and those without. This analysis was performed using IBM SPSS Statistics version 27.0 (Armonk, NY: IBM Corp.) for Windows and an unpaired t-test. We considered p-values of less than 0.05 as statistically significant. Results We found the STF in six bones (15%) as follows: four on the left side and two on the right. Humeri with the STF had smaller mean head circumference, length, and shaft circumference than those without the foramen. However, this difference was not statistically significant (p>0.05). The mean width of the medullary canal in humeri with the STF was significantly smaller (p<0.05) than in bones without the STF. Conclusions Our study revealed that humeri with an STF present a significantly smaller diameter of the medullary canal, which can impact surgical procedures like retrograde intramedullary nailing. Clinicians should consider this when planning surgeries to avoid iatrogenic fractures and enhance procedural efficiency. Our data also suggest that larger humeri are less likely to have an STF, potentially influencing pre-surgical planning and fracture risk assessment.

Reduction of geometric misfit in straight antegrade humeral nailing by evaluating the effect of entry point angulation using a three-dimensional computational analysis

BACKGROUND

Straight antegrade intramedullary nails are generally inserted utilising the apex as the surgical entry point in accordance with the mechanical axis of the bone. Our objective is to optimise the bone-nail fit in intramedullary nailing by subjecting the surgical entry point to varying angulations in both the mediolateral and anterior-posterior directions via a quantitative fit assessment in each configuration to identify the optimal angulation, defined as the angulation with the lowest occurrence of thin-out to improve nail fitting within the humerus.

METHODS

Computed tomography (CT) scans from 10 cadaveric humeri models were used to generate three-dimensional bone models. The centreline profile of each humerus model was determined by dividing the humerus into multiple slices and identifying its respective centroid. The guidewire and nail models were then established and inserted into the humerus using the apex as the standard entry point. The bone-nail fit was measured utilising three fit quantification parameters: thin-out distance, nail protrusion volume into the cortical shell and deviation distance (top, middle, bottom) between the nail's longitudinal axis and medullary cavity centroid.

FINDINGS

Results revealed a statistically significant association between angulation and occurrence of thin-out (p < .001) and showed that the optimally angulated entry point resulted in decreased cortical breach across the nail insertion depth compared to the standard entry point.

INTERPRETATION

Our findings suggested that the current straight nail design may require further modifications to optimise the nail trajectory within the medullary canal by decreasing the bone-nail geometric mismatch to potentially maximise its working length.

Apex posterior angulation of the humerus: A characterization of normal sagittal plane anatomy with implications for surgical fixation

INTRODUCTION

An understanding of the sagittal plane morphology of the humerus is relevant during surgical fixation of humeral fractures but is not well described in the literature. The purpose of this study was to better characterize the native sagittal plane morphology of the humerus.

MATERIALS AND METHODS

170 patients with uninjured full length lateral humerus radiographs were retrospectively evaluated. The angle between the proximal humeral diaphyseal axis and the distal humeral diaphyseal axis was identified and measured. The proximal axis was defined by two points equidistant from the anterior and posterior cortex 10 mm and 100 mm distal to the metaphyseal flare, and the distal axis by two points at 10 mm and 50 mm proximal to the capitellum/trochlea. The relative location of the center of rotation of angulation (CORA) was calculated as a percentage of humeral length.

RESULTS

114 radiographs were included in the analysis (66 right humeri, 48 left humeri). The average apex posterior angulation was 6.5 +/- 2.9°. The CORA occurred at an average of 80% (SD+/-13%) of the length of the humerus (proximal to distal). Total humeral length and absolute distance to CORA were greater in males compared to females (364 ± 50 mm versus 326 ± 30 mm; p<0.001; 290 ± 68 mm versus 260 ± 48 mm; p=0.003), but there were no significant sex differences with respect to magnitude of the apex posterior angulation (p=0.077) or location of CORA as a percentage of total humeral length (p=0.916). There were no statistically significant associations between age and total humeral length (p=0.056), distance to CORA (p=0.130), location of CORA as percentage of total humeral length (p=0.753), or magnitude of angulation (p=0.075).

CONCLUSION

An apex posterior bow consistently exists in the distal one-quarter of the humerus that is consistent across ages and between sexes. This normal anatomic bow is important to recognize to avoid an extension malreduction and has implications for implant fit and contouring.

The conundrum of olecranon aperture and its relation to the distal end of the humerus in a modern Indian population: An anatomical and surgical perspective

PURPOSE

We aimed to clarify the morphology of the olecranon aperture (OA) of the humerus with its relationship to the distal end of the humerus (epicondylar width) and the width of the medullary canal.

METHODS

In total, 156 dry adult humeri were examined for the presence of OA. When present, we reported their shape, measured transverse (TD) and vertical diameter (VD), the distance from its medial border to the tip of medial epicondyle (D1), lateral border to the tip of lateral epicondyle (D2) and lower border to the tip of trochlea (D3). The epicondylar width (EW) and the width of the medullary canal were also measured in all the humeri.

RESULTS

OA was reported in 32 humeri (20.6%) with left side predominance, translucent septum in 35.8%, and opaque septum in 43.6%. The most typical shape noted was oval. On right side, mean VD and TD was 4.30±0.54mm and 5.85±0.45mm, respectively, whereas on left, these value were 4.21±0.56mm and 5.64±0.43mm, respectively. The mean of D1, D2 and D3 was 25.86±0.43mm, 26.50±0.28mm and 15.07±0.53mm on right and 24.80±0.41mm, 26.84±0.21mm and 15.81±0.31mm on left with significant difference (P<0.05). The medullary canal was significantly smaller in humeri with OA.

CONCLUSION

Topographic location of OA may have possible role in determining safe zone for retrograde nailing in supracondylar humeral fractures. Since OA has a direct relation to the size of the intramedullary canal, it is crucial during preoperative planning and choosing an adequate surgical approach involving lower segment of humerus.

Development of an additively-manufactured functionally-graded expandable implant via the application of the adaptive response surface method: feasibility study on intramedullary humerus nail

The paper introduces the concept of the rational design of a deployable humeral intramedullary nail plug based on a honeycomb structure used for the surgical treatment of humeral shaft fractures. The concept serves for to restore the axial alignment of bone fragments and to maintain stability via bone-nail friction and locking screws. The design nail plug was gained by optimisation process the Latin Hypercube Sampling Design algorithm and Multi-Objective Genetic Algorithm. It was shown that we can use statistical shape function combined by 3 D printing for designing of a new rationally designed implants.

Clinical anatomy and biomechanics of the elbow

The anatomy of the elbow joint had been studied extensively over the last 2 decades. The increased understanding of the anatomy and contribution of the anatomical structures to the elbow biomechanics had enabled surgeons to improve the results of surgical reconstruction and fracture fixation. This review articles intend to summarise the salient functional and clinical anatomical and relevant biomechanical data that had been published recently.