Kyphoplasty

Published on 10/03/2015 by admin

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Chapter 18 Kyphoplasty

Yong-Chul Kim, MD, PhD, Seung-Eun Shim, MD, PhD

Balloon kyphoplasty is a minimally invasive option for treating vertebral compression fractures. It can be performed as an outpatient procedure and can provide immediate pain relief. The patient can return to activities of daily living just after the procedure, which stabilizes vertebral fractures and reduces spinal deformity by restoring vertebral body anatomy and height.

The incidence of cement leakage and other procedure-related complications is low, and pain relief has been reported in more than 90% of patients. The procedure time requires 20 to 40 minutes per level, and the medical cost is higher than that of vertebroplasty. Supplementary facet joint injections or medial branch blocks may improve the level of pain relief in some cases.

Treatment objectives of kyphoplasty

The treatment objectives are to provide an early return to function, to relieve pain, and to restore the anatomy by reducing and stabilizing the fracture, restoring vertebral height, and diminishing the spinal deformity.

Indications

Kyphoplasty is performed in patients with recent vertebral fractures due to osteoporosis, angiomas, myelomas, metastasis, and so on, who present with pain refractory to conservative treatment including bed rest and drug treatment. The best results are obtained when the vertebral collapse has occurred recently—that is 3 months or less before the patient’s presentation [1,2].

Contraindications

Contraindications to kyphoplasty may be absolute or relative [1–3]. Absolute contraindications are as follows:

image Coagulation disorders
image Local infection in the proposed site of access (osteomyelitis or spondylodiscitis)
image Unstable fractures or neoplasms with involvement of the posterior vertebral wall (i.e., complex fractures with or without retropulsed fragments) and accompanying spinal canal compromise
image Vertebra plana (complete vertebral body collapse)

Relative contraindications to the procedure are as follows:

image Less than one third of the original vertebral body height remaining
image Damaged pedicles or articular facets
image Tumor invasion into the spinal canal, making any potential leakage of even a small amount of cement into the already compromised canal especially hazardous

Complications

There is an overall incidence rate of complications with this procedure ranges from 0 to 9.8% [4–9]. The most common is cement extravasation, which may be avoided with the following precautions [10]:

image Filling the void with thick, toothpaste-like cement using a low-pressure injection yields less cement leakage than filling the interstices of a fractured vertebra with thin, less viscous cement via a high-pressure injection, as is done in vertebroplasty.
image Adequate imaging with high-quality digital fluoroscopy, adequate cement opacification with sterile barium, and injection of cement which is not too liquefied can avoid leakage.

Other, extremely rare complications of kyphoplasty are as follows:

image Pneumothorax and rib fracture after thoracic kyphoplasty
image Pulmonary embolism
image Bleeding or spinal epidural hematoma
image Radiculopathy
image Paraplegia
image Infection
image Cerebrospinal fluid leakage
image Transient adult respiratory distress syndrome

Preoperative preparation

The physician should obtain a description of the presenting symptoms from the patient, which may include complaints of limitation of motion, and varying degrees of local pain with or without radiation around the trunk and further anteriorly.

The physical examination at the level of the recent fracture(s) reveals corresponding tenderness upon deep palpation and pain provoked by percussion.

The imaging diagnosis would include the following:

image Plain spine anteroposterior (AP) and lateral films
image Computed tomography (CT) scan with or without three-dimensional imaging to assess details of the bony architecture in cases of suspicion of a posterior cortical fracture (Fig. 18-1)
image Bone scan to determine the most recent fracture(s) in patients with multiple fractures [11]
image Magnetic resonance imaging (MRI) to detect signal change caused by bone edema at the level of a recent fracture (Fig. 18-2)
image

Figure 18–1 Computed tomography scan with three-dimensional images of a vertebral body fracture from the right (A) and left (B).

image

Figure 18–2 Left, A T1-weighted sagittal magnetic resonance image shows a complete vertebral body collapse (vertebra plana) at T12 and L2. A few fracture fragments of T12 compress the spinal cord anteriorly. Right, A bone scan shows no radiotracer uptake at the T12 and L2 levels, indicating chronic, rather than acute, fractures at these levels. At the L3 lower vertebral body, there is a loss of high signal intensity on the T1-weighted image and a high uptake on the bone scan image, indicating an acute pathologic process. Kyphoplasty at the T12 and L2 levels are contraindicated, whereas a kyphoplasty at L3 is indicated.

Radiologic anatomy for kyphoplasty

Radiologic landmarks for kyphoplasty should be identified as follows (Fig. 18-3)

image Pedicles, to define the starting point of bone access needle on each side
image Spinous process, to gauge vertebral body rotation
image End plates, to enable planning of a posterior-to-anterior trajectory
image Posterior cortical margin, to avoid the anterior margin of the spinal canal
image

Figure 18–3 Fluoroscopic views of the lumbar spine. (A) On a true anteroposterior (AP) view, the pedicles (black circles) should be located equidistant from both lateral margins of the corresponding vertebral bodies, and the spinous process should also be located at the midline of the width of the vertebral body. (B) On an oblique view, the pedicle (dotted circle) should be visualized at its widest and most circular aspects. (C) On a true lateral view, the two pedicles should be superimposed. For assessment of the location of the needle tip and its correct trajectory, frequent check of the true AP and lateral views is essential.

Methods of kyphoplasty

The two methods of kyphoplasty currently performed, along with available products for them, are as follows:

image Balloon kyphoplasty (Kyphon, Inc., Sunnyvale, CA)
image Bone graft kyphoplasty: OptiMesh Deployable Grafting System (Spineology, Inc., St. Paul, MN) (Fig. 18-4)
image

Figure 18–4 The OptiMesh system. (A) The OptiMesh graft containment device in its unfilled (left) and filled (right) states. (B) Allograft bone material prepared for the bone filling tube. (C) An expandable reamer. (D) Preoperative (left) and postoperative (right) computed tomography scans of three-level OptiMesh implantations for treatment of three vertebral fractures. (E) The surgeon fills the cavity with allograft bone through the bone filling tube. Pressure is exerted firmly with a mallet.

(Courtesy of Spineology, Inc., St. Paul, MN.)

Balloon kyphoplasty is described in detail in this chapter.

Instrumentation

Operating Room Setup

Figure 18-5 depicts the operating room setup for balloon kyphoplasty, consisting of the following:

image Radiolucent operating table
image A high quality C-arm (fluoroscope)
image An anesthesia machine
image Monitoring devices
image Equipment for cardiopulmonary resuscitation
image

Figure 18–5 The operating room to be used for kyphoplasty contains a radiolucent operating table and a high quality C-arm (fluoroscope), both of which are mandatory for maximal procedural safety. An anesthesia machine, monitoring devices, and equipment for cardiopulmonary resuscitation are also necessary for the patient’s safety.

Kyphoplasty Kit

Figure 18-6 illustrates the components of the balloon kyphoplasty system manufactured by Medtronic, Sunnyvale, CA, use of which is described in the procedure section of this chapter:

image KYPHON® Bone Access Needle, 11-gauge
image KYPHON® Osteo Introducer® System (Fig. 18-7)
image KYPHON® Precision Drill
image Guide Pins
image KYPHON® Bone filler device (Fig. 18-8)
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