Cervical Disc Replacement

By Jaimig Aljorna

Cervical disc replacement is a minimally invasive surgical procedure which aims to remove a damaged disc and substitute it with a prosthesis. What is the cervical disc? Cervical vertebrae are located in the neck. Between the cervical vertebrae, there is a buffer, called intervertebral disc. Its main function is absorbing the loads to which the…

Percutaneous Facet Screw Fixation of Lumbar Spine with CT and Fluoroscopic Guidance: A Feasibility Study.

By London Spine
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Percutaneous Facet Screw Fixation of Lumbar Spine with CT and Fluoroscopic Guidance: A Feasibility Study.

Radiology. 2013 Mar 12;

Authors: Amoretti N, Amoretti ME, Hovorka I, Hauger O, Boileau P, Huwart L

Abstract
Purpose:To assess the feasibility of computed tomography (CT)- and fluoroscopy-guided percutaneous facet screw fixation following anterior lumbar interbody fusion (ALIF) or anterior pseudarthrosis in adults.Materials and Methods:Institutional review board approval and informed consent were obtained for this study. One hundred seven consecutive adult patients (46 men, 61 women; mean age ± standard deviation: 56.3 years ± 12.9) with ALIF (n = 79) or anterior pseudarthrosis (n = 28) were prospectively treated by means of percutaneous facet screw fixation with CT and fluoroscopic guidance. Two 4.0-mm cannulated screws were placed per level to fix facet joints by using either a translaminar facet or transfacet pedicle pathway. Only local anesthesia was used during these procedures. Procedural time was noted for each patient. Postoperative follow-up ranging from 1 year to 3 years was assessed by using Macnab and radiologic criteria.Results:The mean procedure times for a lumbar single-level and a double-level fusion ranged from 15 to 25 minutes and from 40 to 50 minutes, respectively. All the transfacet pedicle (n = 182) and translaminar facet (n = 56) screws were successfully placed in one attempt. Radiographic fusion was observed within the year following posterior fixation in all patients despite one translaminar screw failure. According to the Macnab criteria, the clinical results were classified as excellent in 92 (86%) and good in 15 (14%) of 107 patients at the time of their last follow-up examination.Conclusion:This feasibility study showed that CT- and fluoroscopy-guided percutaneous facet screw fixation is a rapid, safe, and effective method.© RSNA, 2013.

PMID: 23481163 [PubMed – as supplied by publisher]

Accuracy of pedicle screw insertion in the cervical spine for internal fixation using frameless stereotactic guidance.

By London Spine
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Accuracy of pedicle screw insertion in the cervical spine for internal fixation using frameless stereotactic guidance.

J Neurosurg Spine. 2008 Mar;8(3):237-45

Authors: Rath SA, Moszko S, Schäffner PM, Cantone G, Braun V, Richter HP, Antoniadis G

Abstract
OBJECT: Although transpedicular fixation is a biomechanically superior technique, it is not routinely used in the cervical spine. The risk of neurovascular injury in this region is considered high because the diameter of cervical pedicles is very small and their angle of insertion into the vertebral body varies. This study was conducted to analyze the clinical accuracy of stereotactically guided transpedicular screw insertion into the cervical spine.
METHODS: Twenty-seven patients underwent posterior stabilization of the cervical spine for degenerative instability resulting from myelopathy, fracture/dislocation, tumor, rheumatoid arthritis, and pyogenic spondylitis. Fixation included 1-6 motion segments (mean 2.2 segments). Transpedicular screws (3.5-mm diameter) were placed using 1 of 2 computer-assisted guidance systems and lateral fluoroscopic control. The intraoperative mean deviation of frameless stereotaxy was < 1.9 mm for all procedures.
RESULTS: No neurovascular complications resulted from screw insertion. Postoperative computed tomography (CT) scans revealed satisfactory positioning in 104 (90%) of 116 cervical pedicles and in all 12 thoracic pedicles. A noncritical lateral or inferior cortical breach was seen with 7 screws (6%). Critical malplacement (4%) was always lateral: 5 screws encroached into the vertebral artery foramen by 40-60% of its diameter; Doppler sonographic controls revealed no vascular compromise. Screw malplacement was mostly due to a small pedicle diameter that required a steep trajectory angle, which could not be achieved because of anatomical limitation in the exposure of the surgical field.
CONCLUSIONS: Despite the use of frameless stereotaxy, there remains some risk of critical transpedicular screw malpositioning in the subaxial cervical spine. Results may be improved by the use of intraoperative CT scanning and navigated percutaneous screw insertion, which allow optimization of the transpedicular trajectory.

PMID: 18312075 [PubMed – indexed for MEDLINE]

Safe surgical technique: cement-augmented pedicle screw instrumentation and balloon-guided kyphoplasty for a lumbar burst fracture in a 97-year-old patient.

By London Spine
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Safe surgical technique: cement-augmented pedicle screw instrumentation and balloon-guided kyphoplasty for a lumbar burst fracture in a 97-year-old patient.

Patient Saf Surg. 2013 Jan 8;7(1):3

Authors: Freude T, König B, Martetschläger F, Siebenlist S, Neumaier M, Stöckle U, Döbele S

Abstract
ABSTRACT: BACKGROUND: During the last few years, an increasing number of unstable thoracolumbar fractures, especially in elderly patients, has been treated by dorsal instrumentation combined with a balloon kyphoplasty. This combination provides additional stabilization to the anterior spinal column without any need for a second ventral approach. CASE PRESENTATION: We report the case of a 97-year-old male patient with a lumbar burst fracture (type A3-1.1 according to the AO Classification) who presented prolonged neurological deficits of the lower limbs – grade C according to the modified Frankel/ASIA score. After a posterior realignment of the fractured vertebra with an internal screw fixation and after an augmentation with non-absorbable cement in combination with a balloon kyphoplasty, the patient regained his mobility without any neurological restrictions. CONCLUSION: Especially in older patients, the presented technique of PMMA-augmented pedicle screw instrumentation combined with balloon-assisted kyphoplasty could be an option to address unstable vertebral fractures in “a minor-invasive way”. The standard procedure of a two-step dorsoventral approach could be reduced to a one-step procedure.

PMID: 23298619 [PubMed – as supplied by publisher]

Posterior decompression and short segmental pedicle screw fixation combined with vertebroplasty for Kümmell’s disease with neurological deficits.

By London Spine
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Posterior decompression and short segmental pedicle screw fixation combined with vertebroplasty for Kümmell’s disease with neurological deficits.

Exp Ther Med. 2013 Feb;5(2):517-522

Authors: Zhang GQ, Gao YZ, Zheng J, Luo JP, Tang C, Chen SL, Wang HQ, Liu K, Xie RG

Abstract
The aim of this study was to investigate the treatment of Kümmell’s disease with neurological deficits and to determine whether intravertebral clefts are a pathognomonic sign of Kümmell’s disease. A total of 17 patients who had initially been diagnosed with Kümmell’s disease were admitted, one patient was excluded from this study. Posterior decompression and vertebroplasty for the affected vertebrae were conducted. Pedicle screw fixation and posterolateral bone grafts were performed one level above and one level below the affected vertebrae. Vertebral tissue was extracted for histopathological examination. The mean time of follow-up was 22 months (range, 18 to 42 months). The anterior and middle vertebral heights were measured on standing lateral radiographs prior to surgery, one day postoperatively and at final follow-up. The Cobb angle, the visual analog scale (VAS) and the Frankel classification were used to evaluate the effects of the surgery. The VAS, anterior and middle vertebral heights and the Cobb angle were improved significantly one day postoperatively and at the final follow-up compared with the preoperative examinations (P<0.05). No significant differences were observed between the one-day postoperative results and those at final follow-up (P>0.05). The neurological function of all patients was improved by at least one Frankel grade. All patients in this study exhibited intravertebral clefts, and postoperative pathology revealed bone necrosis. One patient (not included in this study) showed an intravertebral cleft, but the pathology report indicated a non-Hodgkin’s lymphoma. The intravertebral cleft sign is not pathognomonic of Kümmell’s disease. Posterior decompression with short-segment fixation and fusion combined with vertebroplasty is an effective treatment for Kümmell’s disease with neurological deficits.

PMID: 23403724 [PubMed – as supplied by publisher]

How is the trachea at risk of injury from pedicle screw insertion in proximal thoracic curve of adolescent idiopathic scoliosis patients?

By London Spine
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How is the trachea at risk of injury from pedicle screw insertion in proximal thoracic curve of adolescent idiopathic scoliosis patients?

Eur Spine J. 2013 Feb;22(2):338-44

Authors: Qian B, Jiang J, Zhu F, Zhu Z, Liu Z, Qiu Y

Abstract
PURPOSE: The rotation or translation of vertebrae in adolescent idiopathic scoliosis (AIS) patients could cause the relative migrations of surrounding vital structures and lead to smaller safe zones for pedicle screw insertion. This study aimed to determine the changed relative position of trachea to spine in the proximal thoracic curve (T1-T4) and to analyze the potential risks of tracheal injuries from pedicle screw insertions in AIS patients.
METHODS: Twenty-three patients with complete proximal thoracic curve (CPT group), 25 patients with fractional proximal thoracic curve (FPT group) and 19 normal subjects with a straight spine (normal group) were included. Axial computed tomography images from T1 to T4 level were obtained to evaluate trachea-vertebral distance (TVD, the closest distance between trachea and vertebral body) and trachea-vertebral angle (TVA, defined as 0° when the trachea was located directly laterally to the left and 180° when directly laterally to the right). The extension line of pedicle axis could cross the anterior wall of vertebra and the posterior wall of the trachea at two points when the trachea was located in the trajectory of the screw passage. If the distance between the two points was less than 5 mm, the trachea was considered to be at a potential risk of injury. The percentages of vulnerable trachea were calculated at each level.
RESULTS: The TVA in the CPT group was significantly larger than that in the FPT group and in the normal group, while the TVA in the FPT group was significantly larger than that in the normal group at the T2-T4 level. The TVD in the FPT group was significantly smaller than that in the CPT group and in the normal group at each level, while the TVD in the CPT group was significantly smaller than that in the normal group at the T2 and T3 levels. No trachea was found to be at risk from screw insertion on both sides in both the CPT group and the normal group. However, it was at a high risk of injury from anterior cortex penetration during right screw insertion in the FPT group. The percentage of trachea at risk from right screw insertion was 40 % at T1 level, 92 % at T2 level, 100 % at both T3 and T4 levels.
CONCLUSIONS: This CT-based study demonstrates that the FPT curve has a smaller safe zone with respect to tracheal injury during screw insertion. Spine surgeons should choose the appropriate screw length to avoid anterior wall perforation.

PMID: 23053757 [PubMed – in process]