20.1 Introduction

Kyphoplasty is a vertebral augmentation procedure designed to treat vertebral compression fractures. The goal of the procedure is to reduce pain, as well as reduce postfracture kyphosis. Kyphoplasty was first performed in 1998 as a minimally invasive procedure to reduce vertebral body fractures. ¹ The American Academy of Orthopaedic Surgeons 2010 guidelines indicate that kyphoplasty is currently “an option for patients who present with an osteoporotic spinal compression fracture on imaging with correlating clinical signs and symptoms, and who are neurologically intact.” ²

Vertebral compression fractures commonly result from either trauma (even minor) in the setting of osteoporosis ^{3 ,​ 4 ,​ 5} or pathologic fracture in the setting of malignancy. ^{3 ,​ 6 ,​ 7 ,​ 8} These types of fractures are associated with spinal deformity, increased pain, compromised pulmonary function, decreased quality of life, and increased mortality. ^{9 ,​ 10 ,​ 11 ,​ 12} Kyphoplasty can effectively help manage pain in this setting and potentially improve sagittal alignment. ^{13 ,​ 14}

Surgical management of compression fractures may involve vertebral augmentation via either vertebroplasty or kyphoplasty. Both surgical procedures have been shown to reduce pain compared to nonsurgical management. ¹⁵ While the procedures are similar, kyphoplasty specifically seeks to remediate the resulting kyphosis from vertebral compression. ¹⁶ The kyphoplasty procedure involves percutaneous injection of bone cement into a fractured vertebrae under image guidance. Prior to cement injection, inflatable bone tamps are placed into the vertebral body to create a negative pressure cavity which is then filled with cement, reducing the fracture and improving the kyphotic deformity. The procedure can be performed in an outpatient setting that is equipped with proper imagine guidance technology. ¹⁷

20.2 Navigation with Kyphoplasty

Recently, some have supplanted traditional fluoroscopic image-guided kyphoplasty with navigated kyphoplasty. This technique has allowed for more precise needle placement and decreased radiation exposure for both the patient and the surgeon. ^{1 ,​ 18 ,​ 19} Navigation is a relatively new tool that was developed in the hope of creating safer and less-invasive procedures across multiple different fields. ²⁰ Some of the most pertinent applications come in the fields of neurosurgery, otolaryngology, and orthopedics. In these cases, the navigational setup creates a digital rendering of the exact position and orientation of surgical instruments in reference to the patient’s anatomy. Some procedures, particularly neurosurgeries, require preoperative MRI scans that are then correlated to intraoperative scans of the patient in his or her current position. Other procedures, mostly orthopedic, do not require special preoperative scans, since the software creates an individualized model of the patient’s anatomy based on defined bony landmarks during the intraoperative scans. For both types of surgery, the surgeons receive relevant information throughout the procedure from the navigation system. ²⁰ Use of navigation systems in spine surgery has demonstrated more accurate crew placement, fewer complications, and an overall greater safety profile than traditional fluoroscopic techniques and can lead to increased confidence by the surgeons in their ability to perform the procedures. ^{20 ,​ 21 ,​ 22}

20.3 Technique

To perform a computer-navigated balloon kyphoplasty, the patient is first placed in the prone position on the operating table and the patient is prepped in the usual sterile manner. Surgical instruments may be calibrated during anesthesia and preparation. The vertebral fractures are localized using fluoroscopy in the lateral and anterior–posterior views. An incision is made one vertebral level rostral to the fractured vertebrae, and a reference base is fixed to this spinous process (at the level above the fracture) ¹ which allows registration of the advanced 3D image (either CT or fluoroscopically based) (Fig. 20‑1). We have used the Siremobil Iso-C3D (Siemens Medical Solutions, Erlangen, Germany), a fluoroscopically based model, to obtain intraoperative multiple axial-plane tomography, which takes an average time of 2 minutes. ¹ The images are automatically registered to a navigation platform such as the VectorVisionENT (Brainlab, Munich, Germany) to process the data. ¹ This 3D map is then registered to the precalibrated instruments allowing stereotactic guidance of instrumentation (Fig. 20‑2). For kyphoplasty, a Jamshidi needle can be calibrated with the system. The needle is then guided into the posterior vertebral column using real-time guidance of the navigation system (Fig. 20‑3). By using this method, the need for repetitive fluoroscopy during this entry step to ensure correct positioning has essentially been eliminated. A guide pin as well as a blunt dissector is then inserted into the posterior third of the fractured vertebral body. A 3-mm working cannula is placed over the blunt dissector into the vertebral body, so that the dissector can be removed and replaced with a 3-mm drill. Drilling into the bone creates a narrow space through which to insert the inflatable bone tamp. An angioplasty injection device equipped with a pressure monitor is connected to the bone tamp. The drill is removed and the bone tamp inserted into the anterior-most part of the predrilled channel, where it is slowly inflated. Bone cement is then slowly injected into the cavity using a 3-mm filler device, and fluoroscopic visualization or O-arm image acquisition can then be used to ensure adequate filling (Fig. 20‑4). After the injection is complete, instruments are removed and the incision closed in a layered fashion. ^{1 ,​ 16}