The Effect of Preoperative Three Dimensional Modeling and Simulation on Outcome of Intracranial Aneursym Surgery

OBJECTIVE

Three-dimensional (3D) printing in vascular surgery is trending and is useful for the visualisation of intracranial aneurysms for both surgeons and trainees. The 3D models give the surgeon time to practice before hand and plan the surgery accordingly. The aim of this study was to examine the effect of preoperative planning with 3D printing models of aneurysms in terms of surgical time and patient outcomes.

METHODS

Forty patients were prospectively enrolled in this study and divided into two groups : groups I and II. In group I, only the angiograms were studied before surgery. Solid 3D modelling was performed only for group II before the operation and was studied accordingly. All surgeries were performed by the same senior vascular neurosurgeon. Demographic data, surgical data, both preoperative and postoperative modified Rankin scale (mRS) scores, and Glasgow outcome scores (GOS) were evaluated.

RESULTS

The average time of surgery was shorter in group II, and the difference was statistically significant between the two groups (p<0.001). However, no major differences were found for the GOS, hospitalisation time, or mRS.

CONCLUSION

This study is the first prospective study of the utility of 3D aneurysm models. We show that 3D models are useful in surgery preparation. In the near future, these models will be used widely to educate trainees and pre-plan surgical options for senior surgeons.

Comparison of antegrade and retrograde cross pin fixation in the surgical treatment of pediatric supracondylar femur fractures: A biomechanical study

PURPOSE

The aim of this study is to compare biomechanical stability of Kirschner wires (K-wires) sent with antegrade and retrograde technique in the fixation of pediatric supracondylar femur fractures.

MATERIALS AND METHODS

A transverse fracture model was created two centimeters above the physis in 24 synthetic bone models suitable for the pediatric femur bone structure. The models were randomly divided into two groups as 12 bones each. In the first group (Group 1), 12 bone fracture models were retrogradely fixed with two cross K-wires. In the second group (Group 2), the fracture was fixed antegradely. In Group 2, both wire ends were allowed to protrude three millimeters from the femoral condyles. The stability of the groups was tested biomechanically by exposing them to varus and extension forces. The forces corresponding to 1 mm, 2 mm, 3 mm and 4 mm displacement and failure loads were calculated in two groups.

RESULTS

According to the test results regarding displacements and failure loads, the retrograde group was found to be significantly stronger than the antegrade group against varus loads (p < 0.05). When the groups were compared in terms of extension strength, the results of the two groups were similar and there was no statistical difference between them (p > 0.05).

CONCLUSION

Retrograde cross K-wires fixation provides a more stable fixation against varus forces. This is important to prevent varus deformity, which is a clinically less tolerable deformity. However, considering that full-weight mobilization of patients is not allowed after surgery in pediatric supracondylar femur fractures, the surgeon should consider that K-wires can also be sent antegrade to decrease the risk of septic arthritis.

Comparison of Biomechanical Properties of Dura Mater Substitutes and Cranial Human Dura Mater : An In Vitro Study

Objective

The aim of this study was to investigate the biomechanical differences between human dura mater and dura mater substitutes to optimize biomimetic materials.

Methods

Four groups were investigated. Group I used cranial dura mater (n=10), group II used Gore-Tex^® Expanded Cardiovascular Patch (W.L. Gore & Associates Inc., Flagstaff, AZ, USA) (n=6), group III used Durepair^® (Medtronic Inc., Goleta, CA, USA) (n=6), and group IV used Tutopatch^® (Tutogen Medical GmbH, Neunkirchen am Brand, Germany) (n=6). We used an axial compression machine to measure maximum tensile strength.

Results

The mean tensile strengths were 7.01±0.77 MPa for group I, 22.03±0.60 MPa for group II, 19.59±0.65 MPa for group III, and 3.51±0.63 MPa for group IV. The materials in groups II and III were stronger than those in group I. However, the materials in group IV were weaker than those in group I.

Conclusion

An important dura mater graft property is biomechanical similarity to cranial human dura mater. This biomechanical study contributed to the future development of artificial dura mater substitutes with biomechanical properties similar to those of human dura mater.

Biomechanical Properties of the Cranial Dura Mater with Puncture Defects : An In Vitro Study

Objective

The primary aim of this investigation was to explore the nature of dura mater biomechanics following the introduction of puncture defect(s).

Methods

Twenty-eight dura mater specimens were collected during autopsy from the department of forensic medicine of the authors' institution. Specimens were divided randomly into one of four groups : group I (cranial dura mater; n=7), group II (cranial dura mater with one puncture defect; n=7); group III (cranial dura mater with two puncture defects; n=7), and group IV (cranial dura mater with three puncture defects; n=7).

Results

The mean±standard deviation tensile strengths of the dura mater were 8.35±3.16, 8.22±3.32, 7.13±1.77, and 6.94±1.93 MPa for groups I, II, III, and IV, respectively. There was no statistical difference between all groups. A single, two or more punctures of the dura mater using a 20-gauge Quincke needle did not affect cranial dura tensile strength.

Conclusion

This biomechanical study may contribute to the future development of artificial dura mater substitutes and medical needles that have a lower negative impact on the biomechanical properties of dura mater.