Bilateral dual iliac screw pelvic fixation for adult spinal deformity: a case report of a superior gluteal artery pseudoaneurysm secondary to aberrant iliac screw trajectory

PURPOSE

To present a case of a pseudoaneurysm of a branch of the left superior gluteal artery (SGA) secondary to lateral wall perforation from an iliac screw and its subsequent evaluation and management.

METHODS

Case report.

RESULTS

A 67-year-old female with a history of degenerative flatback and scoliosis and pathological fractures of T12 and L1 secondary to osteodisciitis underwent a single0stage L5-S1 ALIF and T9-pelvis posterior instrumented fusion with bilateral dual iliac screw fixation, revision T11-S1 decompression, and T12 and L1 irrigation and debridement and partial corpectomies. During the operation, non-pulsatile bleeding was encountered after creating an initial trajectory for the more proximal of the two left iliac screws. While the initial post-operative course was benign, the patient was readmitted for hypotension and anemia. Computed tomography of the abdomen/pelvis demonstrated a pseudoaneurysm (2.3 cm × 2.1 cm × 2.3 cm) of a branch of the left SGA. Diagnostic angiogram confirmed a pseudoaneurysm off of one of the branches of the left SGA. Endovascular embolization using multiple coils resulted in a complete cessation of blood flow in the pseudoaneurysm. At 2 years follow-up, no symptoms suggestive of recurrence of the pseudoaneurysm were reported.

CONCLUSIONS

A pseudoaneurysm of a branch of the left superior gluteal artery as a result of lateral wall perforation from an aberrantly placed iliac screw during an adult spinal deformity operation involving dual screw pelvic fixation is reported. Prompt recognition, multidisciplinary collaboration, and appropriate intervention were key in achieving a successful outcome and preventing further morbidity.

Feasibility of a Novel Fluoroscopic Trainer for the Orthopaedic Trainee

OBJECTIVE

We sought to create a novel method of teaching orthopedic trainees to efficiently obtain intraoperative radiographs using nonfluoroscopic digital cameras. Specifically, teaching them to make minor, uniplanar, adjustments while limiting the number of fluoroscopy images obtained during placement of a guidewire "start-point," for intramedullary nailing.

DESIGN

Prospective cohort study including medical students from 2 academic centers. Two nonfluoroscopic digital cameras simulating orthogonal fluoroscopic images were utilized. A sponge was used to simulate soft tissue resistance while navigating a guidewire to the desired starting point. Three cannulated parallel cylinders in a triangular configuration are used to simulate our "start point." Students completed 4 phases; trial and error, teaching, testing and retention.

SETTING

The protocol was completed at a single academic teaching hospital at the primary authors institution.

PARTICIPANTS

We utilized medical students from 2 GME accredited medical schools to complete the protocol. Students were selected from orthopedic surgery interest groups at their respective institutions and participation was voluntary.

RESULTS

Twenty-one medical students completed the protocol. The number of seconds to achieve each target along with the number of pictures to achieve each target were recorded and averaged. The paired t-test was used to compare the difference between phases. There is a statistically significant difference in the mean number of seconds to achieve each target between phase 1 (baseline) and phase 3 (testing) (p < 0.0001). This statistically significant difference was retained in phase 4 (retention) (p < 0.0001).

CONCLUSIONS

We were able to demonstrate a statistically significant decrease in the number of images and time to obtain the correct "start point." This could theoretically decrease operative time and morbidity while teaching students in a low-stress training environment without exposure to radiation.

3D imaging of the vagus nerve fascicular anatomy with cryo-imaging and UV excitation

Vagus nerve stimulation (VNS) is a method to treat drug-resistant epilepsy and depression, but therapeutic outcomes are often not ideal. Newer electrode designs such as intra-fascicular electrodes offer potential improvements in reducing off-target effects but require a detailed understanding of the fascicular anatomy of the vagus nerve. We have adapted a section-and-image technique, cryo-imaging, with UV excitation to visualize fascicles along the length of the vagus nerve. In addition to offering optical sectioning at the surface via reduced penetration depth, UV illumination also produces sufficient contrast between fascicular structures and connective tissue. Here we demonstrate the utility of this approach in pilot experiments. We imaged fixed, cadaver vagus nerve samples, segmented fascicles, and demonstrated 3D tracking of fascicles. Such data can serve as input for computer models of vagus nerve stimulation.