Kyphosis and canal compromise due to refracturing of an L1 cemented vertebra managed with posterior surgery alone.

BACKGROUND: An already cemented vertebral body rarely refractures and its occurrence may be signaled by the reappearance of pain and/or significant vertebral collapse/kyphosis resulting in canal compromise and neurological deterioration. CASE DESCRIPTION: An 81-year-old male originally underwent an L1 kyphoplasty for an osteoporotic compression fracture. Nine months later, he presented with the late onset of recurrent collapse of the cemented vertebral body, leading to pain, kyphosis, and canal compromise. Surgery warranted total L1 corpectomy, reconstruction of the anterior column, and a posterior fixation through a purely posterior approach (posterior vertebral column resection [pVCR]).
CONCLUSION: Here, we presented the safety/efficacy of utilizing a purely posterior approach (e.g., including L1 corpectomy, reconstruction of the anterior column, and posterior fusion: pVCR) in the management of a repeated fracture of a cemented L1 vertebra resulting in kyphosis and canal compromise. Copyright:

INTRODUCTION

Percutaneous vertebroplasty (PVP) and percutaneous kyphoplasty (PKP) are increasingly used to treat osteoporotic vertebral compression fractures. However, one of the late, but rare complications, is the refracturing of the cemented vertebra.[6,7,9,10,12,16] Here, in a patient with a recurrent/symptomatic L1 compression fracture that resulted in kyphosis and canal compromise, we utilized a purely posterior approach (e.g., posterior vertebral column resection [pVCR]) that included the performance of an anterior corpectomy, reconstruction of the anterior column, and posterior vertebral body fusion.[4,13,14]

CASE REPORT

An 81-year-old male presented with a mild paraparesis of 2 months duration. Nine months before admission, he had undergone an L1 PKP for an osteoporotic fracture.

Radiological assessment

The anteroposterior (AP) thoracolumbar plain radiograph showed two symmetric kyphoplasty cement collections within the L1 vertebral body, while the lateral radiograph showed two wedge-shaped lateral compartments which were attached with a narrow medial bridge. Although the height of the anterior compartment was preserved with the PKP, the wedge-shaped posterior compartment was now significantly kyphotic and had migrated dorsally into the spinal canal resulting in significant conus/cauda equina compression [Figure 1].

Figure 1:

(a) Lateral plain radiograph shows refracture of cemented L1, note that the posterior compartment is pushed back associated with canal compromise and kyphosis, (b) anteroposterior lumbar X-ray demonstrates two cemented lumps.

Surgery

The pVCR of the L1 vertebra first required pedicle screw fixation placed above and below the fractured L1 vertebral level. Next, an L1 corpectomy was performed to reset the previously cemented L1 vertebra followed by reconstruction of the anterior column utilizing a tibial shaft allograft [Figures 2-4]. Finally, posterior stabilization was completed. Postoperatively, the plain thoracolumbar X-ray demonstrated adequate alignment [Figure 5]. Within 3 weeks, the patient was using a walker, and by 6 weeks, he was ambulating independently. Unfortunately, the patient passed away 14 months after the original surgery due to a pulmonary infection (e.g., unrelated to the spine surgery) resulting in sepsis and renal failure.

Figure 2:

(a) The bone cement is demonstrated at the beginning of spondylectomy, (b) trying to remove cemented lump, (c) is almost removed.

Figure 4:

Intraoperative photograph, (a) the lump is removed, (b) spondylectomy done, (c) replacement of the site with allograft.

Figure 5:

Postoperative lumbar X-ray, (a) anteroposterior radiograph shows proper placement of the allograft, note good coronal alignment, (b) lateral radiographs show correction of kyphosis and good sagittal alignment, note pedicle screws cement augmentation.

Intraoperative fluoroscopy (a) shows complete spondylectomy, (b) the anterior column is reconstructed with a tibial shaft allograft.

DISCUSSION

One of the late sequelae of PVP and PKP procedures is the refracturing of cemented vertebrae that can occur from 0.56% to 3.7% of PVP and from 9.7% to 12.5% of PKP cases.[6,8,9,15,16]

Pathogenesis and rates of PVP and PKP refractures

Several studies have demonstrated that the increased “distance between polymethylmethacrylate and the endplate” increases the rate of refracture.[1,5,7] The intervertebral cleft is another risk factor if not properly sealed during the initial procedure.[6]

Distribution of cement

The distribution pattern for cement is classified into two types: (1) local solid lumps or (2) the trabecular/diffuse types.[5,7] In the localized solid lump pattern, the cement is confined to a small area within the anterior two-thirds of the vertebral body (e.g., particularly within the middle third of the body); it results in stress shielding, thereby increasing the risk of microfracture and progressive vertebral body height loss within the noncemented areas. For the trabecular or diffuse patterns, the cement is dispersed and fills the trabecular bone of the additional posterior one-third of the vertebral body.[5,7]

Rates of vertebral recollapse

Recollapse of a previously cemented vertebral body most often occurs within the thoracolumbar region. Infrequently, it is seen involving the low lumbar levels and only rarely within the thoracic spine itself.[2,3,5-12] The interval between initial cement augmentation and refracture varies from 3 to 6 months for PKP and from 6 to 16 months with PVP.[6,8,9,12,15,16] The differences in the intervals between refracturing the following initial PKP and PVP can be easily explained by the differences in the distribution patterns of the originally injected cement.

Clinical presentation of recurrent vertebral recollapse

Clinically, the refracturing of a vertebral body following initial PKP and PVP results in recurrent localized pain and/ or progressive kyphosis with canal compromise and focal neurological deficits. This can be managed with repeated vertebroplasty (e.g., using a single Jamshidi needle).[2,3,11,15] However, for those with significant vertebral height loss, a kyphotic deformity, and canal compromise, surgical intervention may be required. Here, we describe a posterior only technique (e.g., pVCR) that offers 360° reconstruction of the vertebral column including anterior corpectomy, anterior stabilization, and posterior fusion. In the future, this pVCR technique may prove to be safe and effective for managing recurrent vertebral body fractures following PKP and PVP.

CONCLUSION

With the appearance of localized pain after prior PVP or PKP, or the onset of kyphosis with a neurological deficit, routine AP and lateral radiographs may document recurrent vertebral body fracture that may be managed with a posterior only technique (pVCR) that offers unique 360° spinal correction.