Development of hepatic pseudotumors for image-guided interventional and surgical research in a large animal model

Purpose

Real-time image guidance and navigation have become increasingly important in an era of minimally invasive interventional and surgical procedures in the liver. To develop, test, and implement tools for real-time image guidance, the authors sought to create an in vivo tumor mimic with realistic imaging and treatment capabilities.

Materials and Methods

Hepatic pseudotumors were created by injecting 1–2 mL of alginate (a hydrocolloid) directly into the liver parenchyma in eight live pigs and two dog cadavers. Tumors were imaged by B-mode ultrasound (US), US elasticity imaging, multi–detector row computed tomography (CT), CT fluoroscopy, and magnetic resonance (MR) imaging to assess imaging capabilities. Procedures performed with the alginate pseudotumors included radiofrequency (RF) ablation and robotic needle guidance.

Results

Twenty-four hepatic pseudotumors were created, ranging in size from 10 mm to 28 mm at an average depth of 6 mm. Average time of preparation and insertion was 3 minutes. All tumors were palpable under the surface of the liver and were easily visible on B-mode US, US elasticity imaging, CT, and MR imaging. Tumors were successfully “treated” with RF ablation, and gross examination of the liver showed good encompassment of the tumor by the zone of thermal coagulation. In addition, the pseudotumors allowed for easy introduction of various types of needles, including RF ablation probes and experimental steerable needles.

Conclusions

Alginate pseudotumors can easily be imaged and allow for different procedures to be performed. This model can be used for various research purposes.     

Radiographic assessment of surgical treatment of post-traumatic syringomyelia

Context: Symptomatic post-traumatic syringomyelia can affect the quality of life in patients whose neurologic function has already been impacted by a spinal cord injury.Objective: To investigate the radiographic and clinical outcomes following surgery for syringomyelia, we present a literature review along with a case series from a single surgeon’s experience.Methods: A retrospective review was conducted on patients with post-traumatic syringomyelia who were treated by a single surgeon. Thirty-four patients who underwent surgical treatment consisting of syrinx fenestration, lysis of adhesions, and duraplasty were identified. In addition, a narrative literature review was conducted with a primary focus on diagnosis and management of post-traumatic syringomyelia.Results: Literature review suggests that regardless of age, sex, vertebral location, or severity of trauma, patients who experience a spinal cord injury should be closely monitored for post-traumatic syringomyelia. Retrospective review of our 34 patients revealed 24 patients for whom pre- and post- operative MRI was available. The predominant location of the injury was cervical (15). The average syrinx length, measured in spinal segments, was similar when comparing pre- and post-operative MRIs; average syrinx length was 5.5 and 5.4 spinal segments, respectively. In contrast, syrinx axial dimension was decreased in 16 of the patients post-operatively and stable or increased in the other eight. The change in syrinx size did not correlate with clinical outcomes.Conclusion: Current surgical treatment of post-traumatic syringomyelia involves restoration of normal CSF flow dynamics; further prospective work is needed to correlate the clinical state, radiographic measures, and efficacy of surgical intervention.