Short-term outcomes of percutaneous pedicle screw fixation combined with vertebroplasty: A minimally invasive treatment for Kümmell's disease with intravertebral instability

Abstract

Objective: The aim of this study was to present early clinical and radiological outcomes of percutaneous pedicle screw fixation (PPSF) combined with vertebroplasty (VP) in the treatment of Kümmell's disease with intravertebral instability.

Methods: In this study, 21 consecutive patients (4 male and 17 female; mean age = 75.6 years; age range=65-86 years) who suffered from stage II and III Kümmell's disease with intravertebral instability were prospectively recruited from 2012 to 2016 and treated with PPSF combined with VP. The Cobb angle (CA) or wedge angle (WA) in both flexion and extension positions was measured using lateral radiographs, computed tomography, or magnetic resonance imaging. In addition to these radiological parameters, clinical outcome measures, including the visual analog scale (VAS) and the Oswestry Disability Index (ODI) were collected preoperatively; 1 week and 1, 3, 6, and 12 months postoperatively; and then annually. Complications were also recorded.

Results: The mean follow-up was 19.3 (range=12-36) months. The mean operating time was 135.4 (range, 110-175) min, and the mean estimated blood loss was 106.9 (range, 50-165) mL. The mean VAS score and ODI significantly decreased from 7.7±1.1 and 65.3%±7.7% preoperatively to 3.4±0.6 and 30.0%±7.6% postoperatively, respectively (p<0.05). At the final follow-up, the mean VAS score and ODI were 2.5±0.8 and 21.5%±8.8%, respectively (p>0.05). CA and WA significantly decreased from 26.9°±9.7° and 21.3°±6.0° preoperatively to 12.7°±7.2° to 8.6°±4.5° postoperatively, respectively (p<0.05). At the final follow-up, CA was 4.2°±2.0°, and WA was 4.7°±1.8° (p>0.05). No major complications were encountered during the follow-up period.

Conclusion: PPSF combined with VP seems to be an effective surgical option for the treatment of Kümmell's disease with intravertebral instability.

Level of evidence: Level IV, Therapeutic study.

Figure 1. a, b

Intravertebral instability secondary to Kümmell’s disease was identified using a modified flexion-extension lateral radiograph, CT scan, or MR image. (a) CA or WA in flexion position was measured using lateral radiographs when the patient was on standing position. (b) CA or WA in extension position was measured using a lateral radiograph, CT scan, or MR image when the patient lied with a 10-cm-high towel (long 50 cm×wide 20 cm×high 10 cm) placed beneath the back just caudal to the fractured (index) vertebra for 1 h. Intravertebral instability defined as more than 10° CA or WA was changed preoperatively by comparing the supine cross-table extension lateral radiographs, CT scans, or MR images with standing flexion lateral radiographs

Figure 2

The degree of segmental CA was measured from the upper endplate of the vertebra above the injured vertebra to the lower endplate of the vertebra below the fractured level. WA was measured as the angle between the upper and lower endplates of the fractured vertebral body

Figure 3. a–f

Case 1, male, 72 years, L1 Kümmell’s disease with kyphosis and intravertebral instability. (a, c) Intravertebral instability was identified by a modified flexion-extension lateral radiograph and MR image. (d, e) The patient underwent short-segment percutaneous pedicle screw fixation combined with VP. (f) Radiograph showing at 15 months after surgery, no screws loosened

Figure 4. a–e

Case 2, female, 85 years, T11 Kümmell’s disease with kyphosis and intravertebral instability. (a, b) Intravertebral instability was identified by a modified flexion-extension lateral MR image and CT scan. (c, e) The patient underwent long-segment percutaneous pedicle screw fixation combined with VP. (d) Radiograph showed at 27 months after surgery that no screws loosened, and CA and WA were maintained well

Figure 5

Clinical function perioperatively and at follow-up

Figure 6

Imaging data perioperatively and at follow-up