Pujan Kavakebi

Pedicle-Based Non-fusion Stabilization Devices: A Critical Review and Appraisal of Current Evidence

Over the last decades, spinal fusion has become one of the most important principles in surgical treatment of spinal pathologies. Despite the undoubted benefits of fusion surgery, there are several drawbacks associated with this technique, including adjacent segment degeneration and pseudoarthrosis. Based on biomechanical data, dynamic stabilization of the spine is intended to ameliorate adjacent level degeneration by stabilizing vertebral motion in defined planes and mimicking natural spine movements.In this paper, we review the literature and discuss past and present pedicle-based non-fusion dynamic stabilization devices. Although there is a paucity of high-quality prospective trials, studies have indicated both promising and disappointing results. In comparison to 360° fusion surgery, the perioperative risk seems to be lower. Other complications like screw loosening, however, have been reported with various systems, while a reduction of adjacent segment disease has not yet been demonstrated. The necessary degree of restabilization to achieve pain-free motion seems to vary greatly between patients and current systems are far from perfection. If these problems can be solved, dynamic stabilization may nevertheless be an important option of spinal surgery in the future.

Clinical and radiological effect of medialized cortical bone trajectory for lumbar pedicle screw fixation in patients with degenerative lumbar spondylolisthesis: study protocol for a randomized controlled trial (mPACT)

BackgroundSpinal fusion with pedicle screw fixation represents the gold standard for lumbar degenerative disc disease with instability. Although it is an established technique, it is nevertheless an invasive intervention with high complication rates. Therefore, minimally invasive approaches have been developed, the medialized bilateral screw pedicel fixation (mPACT) being one of them. The study objective is to evaluate prospectively the efficacy and safety of the mPACT technique compared with the traditional trajectory for degenerative lumbar spondylolisthesis.Methods/designThis is a single-center, randomized, controlled, parallel group, superiority trial. A total of 154 adult patients are allocated in a ratio of 1:1. Sample size and power calculation were performed to detect the minimal clinically important difference of 10%, with an expected standard deviation of 20% in the primary outcome parameter, the Oswestry Disability Index, with power of 80%, based on an assumed maximal dropout rate of 20%. Secondary outcome parameters include the EuroQoL 5-Dimension questionnaire, the Beck Depression Inventory, the painDETECT questionnaire and the “timed up and go” test. Furthermore, radiological and health economic outcomes will be evaluated. Follow up is performed until 5 years after surgery. Major inclusion criteria are lumbar degenerative spondylolisthesis with Meyerding grade I or II, which qualifies for decompression and fusion by medialised posterior screw placement with cortical trajectory (mPACT) or by a traditional trajectory for lumbar pedicle screw placement.DiscussionThis trial will contribute to the understanding of the short-term and long-term clinical and radiological postoperative course in patients with lumbar degenerative disc disease, in which the mPACT technique is used.Trial registrationISRCTN registry, ISRCTN99263604. Registered on 3 November 2016.

Transoral vertebroplasty of the lateral mass of C1 using image guidance

BackgroundOsteolytic lesions of the anterior aspects of C1 (lateral mass) are difficult to address in a minimally invasive fashion and are often treated by craniocervical instrumentation.MethodsWe report the feasibility and technical method of transoral vertebroplasty of the lateral mass of the atlas using image guidance and describe the workflow of the procedure. To our knowledge, there has not yet been a technical description of a transoral vertebroplasty using image guidance.ResultsAdequate positioning of the pedicle access needle using image guidance for addressing the lateral mass of C1 through a transoral, permuceous access can be achieved.ConclusionsWith the assistance of image guidance, it is safe and feasible to access the lateral mass of the atlas. This constitutes a minimally invasive and fast alternative for introducing the bone needle to C1 rather than using a fluoroscopic device alone.

How I do it—optimizing radiofrequency ablation in spinal metastases using iCT and navigation

BackgroundExact positioning of the radiofrequency ablation (RFA) probe for tumor treatment under fluoroscopic guidance can be difficult because of potentially small inaccessible lesions and the radiation dose to the medical staff in RFA. In addition, vertebroplasty (VP) can be significantly high.MethodDescription and workflow of RFA in spinal metastasis using iCT (intraoperative computed tomography) and 3D-navigation-based probe placement followed by VP.ConclusionRFA and VP can be successfully combined with iCT-based navigation, which leads to a reduction of radiation to the staff and optimal probe positioning due to 3D navigation.

Intradural synovial cyst of the atlantoaxial joint: a case report

BackgroundIntradural synovial cysts of the cervical spine represent a rare disease entity, causing stenosis of the spinal canal and thereby leading to progressive myelopathy. In particular, at the cranio-cervical junction early intervention is necessary to prevent permanent neurological dysfunction. We present the case of a 74-year-old man who presented with moderate cervicogenic headache, gait disturbance and progressive left-sided weakness. Magnetic resonance imaging (MRI) of the cervical spine confirmed a left-sided cystic mass located anteriorly at the craniovertebral junction compressing the surrounding structures.MethodSurgical decompression was performed by means of a minimal left-sided laminectomy of C1. Postoperatively, the patients symptoms slowly improved, albeit a persistent ataxic gait.ResultsIntraoperatively, a large intradural cyst was removed via a minimal suboccipital craniectomy combined with laminectomy of C1. Histopathological evaluation revealed a synovial cyst without any features of neoplasia. Despite not using craniocervical instrumentation, no clinical or radiological signs of atlantoaxial instability were observed up to 2 years after surgery.ConclusionsCystic lesions located at the atlanto-axial joint are a rare cause of cervical myelopathy. Preoperative imaging of the cervical spine should include not only MRI and computerised tomography (CT) but also dynamic imaging. Dorsal decompression without instrumentation prevents progressive neurological decline and may allow cord function to recover. If there is additional preoperative instability, instrumentation and fusion may be necessary.