11.9.2\ Kiva Device

11.9.2.1\ Discussion

The Kiva VCF (vertebral compression fracture) system flexible implant is designed to provide structural support to the vertebral body and enables injection of bone cement during vertebral augmentation from T6 to L5. The implant appears as a spiral-shaped structure comprised of PEEK, which is visible on x-ray imaging modalities (Fig. 11.133).

11.9.3\ Sacroplasty

11.9.3.1\ Discussion

Analogous to kyphoplasty and vertebroplasty, sacroplasty is a minimally invasive procedure that involves percutaneous injection of polymethylmethacrylate cement into the sacral ala for treatment of sacral insufficiency fractures (Fig. 11.134). The rate of symptomatic improvement ranges from 50% immediately after the procedure to 90% at 1 year. Complications of sacroplasty include premature hardening, leakage of cement into the sacral neural foramina and into the sacroiliac joint, which can limit range of motion, and venous intravasation of cement with the risk of pulmonary embolism.

Fig. 11.133  Kiva device. Frontal radiograph obtained during percutaneous delivery of the device shows the helical structure within the fractured vertebral body (Courtesy of Benvenue Medical, Inc.)

Fig. 11.134  Sacroplasty. The patient has a history of right sacral insufficiency fracture. Coronal CT image shows cement within the right sacral ala (arrow)

11.9.4\ Percutaneous Interbody

Fusion

11.9.4.1\ Discussion

Percutaneous interbody fusion is a minimally invasive method for providing structural support to the level being fused. This can be accomplished using contained bone graft implant, such as OptiMesh. The device consists of an expandable polyethylene terephthalate meshed bag or pouch that is inserted into a voided disc space and then filled with bone graft material. The implant can be used as stand-alone or in

combination with facet or pedicle screws. On imaging, the implant appears as an ovoid hyperattenuating mass within the disc space (Fig. 11.135). Overtime, solid bony fusion should form across the disc space. Potential complications include but are not limited to extrusion and failed fusion.

Another type of percutaneous disc intervention is nucleoplasty in which radiofrequency ablation is performed for treatment of disc herniation. This does not have any significant imaging correlates other than decrease in the disc herniation if successful.

11.9.5\ CT-Guided Epidural Blood

Patch

11.9.5.1\ Discussion

CT-guided percutaneous patching targeted to the dural defect is a minimally invasive alternative to surgery for the treatment of spinal cerebrospinal

a

fluid leaks. The procedure essentially consists of injecting a small amount of contrast material and autologous blood into the epidural space in the region of the suspected location of the dural defect. The distribution of the injected contrast and blood can be observed on CT and MRI soon after the procedure (Fig. 11.136).

b

c

Fig. 11.136  CT-guided epidural blood patch. Initial sagittal STIR MRI (a) shows a fluid collection in the posterior subcutaneous tissues related to cerebrospinal fluid leakage and postoperative findings related to microdiscectomy in the lower lumbar spine. Axial CT image (b) obtained at the completion of the epidural blood patch procedure shows the contrast containing fluid in the right

posterior epidural space (arrow). The blood patch appears as a fluid collection (arrow) along the dorsolateral epidural space related to recent blood patch with mild local mass effect on the thecal on the sagittal STIR MRI obtained 1 day later (c), but the fluid posterior subcutaneous fluid collection has diminished

11.9.6\ Percutaneous Perineural Cyst

Decompression

11.9.6.1\ Discussion

Perineural cysts can occasionally cause symptoms that warrant treatment, such as radicular pain. Percutaneous cyst drainage is a minimally invasive treatment option that can be performed

a

under image guidance. The cyst contents can be aspirated, thereby relieving the mass effect. Catheters that drain the cyst into the subarachnoid space can also be inserted (Fig. 11.137). The resulting decrease in size of the cyst and position of the drainage catheter can be assessed on MRI or CT myelography.

b

Fig. 11.137  Percutaneous sacral perineural cyst decompression with drainage catheter. Preoperative sagittal T2-weighted MRI (a) show a large intrasacral perineural cyst (*) with remodeling of the surrounding bone.

Postoperative sagittal T2-weighted MR image (b) shows a drainage catheter (arrow) inserted within the cyst and interval decrease in size of the cyst