• Journal of Korean Neurosurgical Society
• /
• v.41 no.2
• /
• pp.141-144
• /
• 2007

A vertebral arte [VA] injury presents a difficult problem in atlantoaxial fixation. Recent technical reports described posterior C2 fixation using bilateral, crossing C2 laminar screws. The translaminar screw technique has the advantages of producing little risk of VA injury and the unconstrained screw placement. In addition, biomechanical studies have demonstrated the potential of the translaminar screw technique to provide a firmer construct that is equivalent to methods currently used. We report the successful treatment of C1-2 instability with a left-side high-riding VA. Because of the potential risk of VA injury, we performed a posterior C1-2 fixation with a combination of pedicle screws and a laminar screw in C2. We first placed bilateral C1 lateral mass screws and a right-side C2 pedicle screw. However, placement of the left- side C2 pedicle screw was technically difficult due to a narrow isthmus and pedicle. A laminar screw was inserted instead and authors believe that this posterior C1-C2 fixation with a combination of pedicle screws and a laminar screw in C2 can be a useful alternative technique for the treatment of C1-C2 instability in the presence of a unilateral high-riding VA.

• Journal of Korean Neurosurgical Society
• /
• v.48 no.1
• /
• pp.46-52
• /
• 2010

Objective : In cervico-thoracic junction (CTJ), the use of strong fixation device such as pedicle screw-rod system is often required. Purpose of this study is to analyze the anatomical features of C7 and T1 pedicles related to screw insertion and to evaluate the safety of pedicle screw insertion at these levels. Methods : Nineteen patients underwent posterior CTJ fixation with C7 and/or T1 included in fixation levels. Seventeen patients had tumorous conditions and two with post-laminectomy kyphosis. The anatomical features were analyzed for C7 and T1 pedicles in 19 patients using computerized tomography (CT). Pedicle screw and rod fixation system was used in 16 patients. Pedicle violation by screws was evaluated with postoperative CT scan. Results : The mean values of the width, height, stable depth, safety angle, transverse angle, and sagittal angle of C7 pedicles were $6.9{\pm}1.34\;mm$, $8.23{\pm}1.18\;mm$, $30.93{\pm}4.65\;mm$, $26.42{\pm}7.91$ degrees, $25.9{\pm}4.83$ degrees, and $10.6{\pm}3.39$ degrees. At T1 pedicles, anatomic parameters were similar to those of C7. The pedicle violation revealed that 64.1% showed grade I violation and 35.9% showed grade II violation, overall. As for C7 pedicle screw insertion, grade I was 61.5% and grade II 38.5%. At T1 level, grade I was 65.0% and grade II 35.0%. There was no significant difference in violation rate between the whole group, C7, and T1 group. Conclusion : C7 pedicles can withstand pedicle screw insertion. C7 pedicle and T1 pedicle are anatomically very similar. With the use of adequate fluoroscopic oblique view, pedicle screw can be safely inserted at C7 and T1 levels.

• Journal of Korean Neurosurgical Society
• /
• v.52 no.2
• /
• pp.120-125
• /
• 2012

Objective : To investigate the feasibility of C1 lateral mass screw and C2 pedicle screw with polyaxial screw and rod system supplemented with miniplate for interlaminar fusion to treat various atlantoaxial instabilities. Methods : After posterior atlantoaxial fixation with lateral mass screw in the atlas and pedicle screw in the axis, we used 2 miniplates to fixate interlaminar iliac bone graft instead of sublaminar wiring. We performed this procedure in thirteen patients who had atlantoaxial instabilities and retrospectively evaluated the bone fusion rate and complications. Results : By using this method, we have achieved excellent bone fusion comparing with the result of other methods without any complications related to this procedure. Conclusion : C1 lateral mass screw and C2 pedicle screw with polyaxial screw and rod system supplemented with miniplate for interlaminar fusion may be an efficient alternative method to treat various atlantoaxial instabilities.

• Journal of Korean Neurosurgical Society
• /
• v.50 no.4
• /
• pp.341-347
• /
• 2011

Objective : The purpose of this retrospective study was to evaluate the efficacy and safety of atlantoaxial stabilization using a new entry point for C2 pedicle screw fixation. Methods : Data were collected from 44 patients undergoing posterior C1 lateral mass screw and C2 screw fixation. The 20 cases were approached by the Harms entry point, 21 by the inferolateral point, and three by pars screw. The new inferolateral entry point of the C2 pedicle was located about 3-5 mm medial to the lateral border of the C2 lateral mass and 5-7 mm superior to the inferior border of the C2-3 facet joint. The screw was inserted at an angle $30^{\circ}$ to $45^{\circ}$ toward the midline in the transverse plane and $40^{\circ}$ to $50^{\circ}$ cephalad in the sagittal plane. Patients received followed-up with clinical examinations, radiographs and/or CT scans. Results : There were 28 males and 16 females. No neurological deterioration or vertebral artery injuries were observed. Five cases showed malpositioned screws (2.84%), with four of the screws showing cortical breaches of the transverse foramen. There were no clinical consequences for these five patients. One screw in the C1 lateral mass had a medial cortical breach. None of the screws were malpositioned in patients treated using the new entry point. There was a significant relationship between two group (p=0.036). Conclusion : Posterior C1-2 screw fixation can be performed safely using the new inferolateral entry point for C2 pedicle screw fixation for the treatment of high cervical lesions.

• Journal of Korean Neurosurgical Society
• /
• v.40 no.3
• /
• pp.175-179
• /
• 2006

Objective : The surgical outcome of anterior lumbar interbody fusion[ALlF] with pedicle screw fixation for elderly isthmic spondylolisthesis was analyzed. Methods : Consecutive nineteen elderly patients [aged 65 years or more] with isthmic spondylolisthesis [Grade I or II] who underwent single level ALIF with pedicle screw fixation in 2002 were analyzed. Using clinical chart and mailed questionnaires, preoperative and postoperative Visual Analogue Scale[VAS] of back and leg pain and postopertive Macnab criteria were evaluated. Results : The mean age at the time of operation was 68.4 years [range 65 to 78 years]. Twelve patients underwent ALIF with percutaneous pedicle screw fixation. Seven patients underwent ALIF followed by posterior decompression and pedicle screw fixation. The postoperative complication rate was 10.5% [wound dehiscence in 1 patient and incisional hernia in 1 patient]. There was no postoperative major morbidity or mortality. At a mean follow-up duration of 30.7 months [range 25 to 35 months], 93.3% [14/15] of the patients showed excellent or good outcomes in terms of Macnab criteria. The mean VAS scores of back pain and leg pain significantly decreased after surgery. Conclusion : ALIF with pedicle screw fixation yielded favorable results for elderly isthmic spondylolisthesis in selected cases.

• Journal of Korean Neurosurgical Society
• /
• v.52 no.4
• /
• pp.359-364
• /
• 2012

Objective : Transpedicular screw fixation has some disadvantages such as postoperative back pain through wide muscle dissection, long operative time, and cephalad adjacent segmental degeneration (ASD). The purposes of this study are investigation and comparison of radiological and clinical results between interspinous fusion device (IFD) and pedicle screw. Methods : From Jan. 2008 to Aug. 2009, 40 patients underwent spinal fusion with IFD combined with posterior lumbar interbody fusion (PLIF). In same study period, 36 patients underwent spinal fusion with pedicle screw fixation as control group. Dynamic lateral radiographs, visual analogue scale (VAS), and Korean version of the Oswestry disability index (K-ODI) scores were evaluated in both groups. Results : The lumbar spine diseases in the IFD group were as followings; spinal stenosis in 26, degenerative spondylolisthesis in 12, and intervertebral disc herniation in 2. The mean follow up period was 14.24 months (range; 12 to 22 months) in the IFD group and 18.3 months (range; 12 to 28 months) in pedicle screw group. The mean VAS scores was preoperatively $7.16{\pm}2.1$ and $8.03{\pm}2.3$ in the IFD and pedicle screw groups, respectively, and improved postoperatively to $1.3{\pm}2.9$ and $1.2{\pm}3.2$ in 1-year follow ups (p<0.05). The K-ODI was decreased significantly in an equal amount in both groups one year postoperatively (p<0.05). The statistics revealed a higher incidence of ASD in pedicle screw group than the IFD group (p=0.029) Conclusion : Posterior IFD has several advantages over the pedicle screw fixation in terms of skin incision, muscle dissection and short operative time and less intraoperative estimated blood loss. The IFD with PLIF may be a favorable technique to replace the pedicle screw fixation in selective case.

• Journal of Trauma and Injury
• /
• v.35 no.1
• /
• pp.12-18
• /
• 2022

Purpose: Pedicle screw fixation provides 3-column stabilization, multidimensional control, and a higher rate of interbody fusion. Although computed tomography (CT) is recommended for the postoperative assessment of pedicle screw fixation, its use is limited due to the radiation exposure dose. The purpose of this preliminary retrospective study was to assess the clinical usefulness of low-dose mobile cone-beam CT (CBCT) for the postoperative evaluation of pedicle screw fixation. Methods: The author retrospectively reviewed postoperative mobile CBCT images of 15 patients who underwent posterior pedicle screw fixation for spinal disease from November 2019 to April 2020. Pedicle screw placement was assessed for breaches of the bony structures. The breaches were graded based on the Heary classification. Results: The patients included 11 men and four women, and their mean age was 66±12 years. Of the 122 pedicle screws, 34 (27.9%) were inserted in the thoracic segment (from T7 to T12), 82 (67.2%) in the lumbar segment (from L1 to L5), and six (4.9%) in the first sacral segment. Although there were metal-related artifacts, the image of the screw position (according to Heary classification) after surgery could be assessed using mobile CBCT at all levels (T7-S1). Conclusions: Mobile CBCT was accurate in determining the location and integrity of the pedicle screw and identifying the surrounding bony structures. In the postoperative setting, mobile CBCT can be used as a primary modality for assessing the accuracy of pedicle screw fixation and detecting postoperative complications.

• Journal of Korean Neurosurgical Society
• /
• v.39 no.4
• /
• pp.251-255
• /
• 2006

Objective : To determine the clinical and radiological safety of 15 consecutive patients managed with plate and screw fixation systems applied to the cervical lateral mass. Methods : 15 patients who underwent posterior cervical and T1 arthrodesis were reviewed from Jan 2002 to Dec 2004. Posterior cervical screw and plate fixation was applied on the lateral mass of the cervical spine. The authors have tried lateral mass screw fixation using a modified Magerl's technique [$20^{\circ}$ lateral and $20{\sim}30^{\circ}$ rostral screw trajectory] under preliminary radiological study. The average patient age was $39.73^{\circ}{\pm}11.00\;years$, and the average follow-up period was $9.73^{\circ}{\pm}6.77\;months$. Computed tomography scans taken after surgery were reviewed to confirm the attempted screw trajectory correct and safety. Results : Three of 93 lateral mass screws were malpositioned but clinical damage was not noted. Two of 8 pedicle screws on the T1 vertebrae were not placed on the correct pedicle area. Screw and plate loosening was observed in one case but was not subjected to an additional procedure because of maintained screw position observed during follow-up periods. Conclusion : The results of this study indicate that lateral mass screw fixation using the Modified Magerl's technique on the cervical lateral mass may provide safe and effective application on the patients. In addition, the chance of incorrectly placed screws was higher in T1 pedicle screw fixation than in lateral mass screw fixation of the cervical area.

• Journal of Korean Neurosurgical Society
• /
• v.52 no.4
• /
• pp.346-352
• /
• 2012

Objective : We compared the radiological and clinical outcomes between patients who underwent posterior fixation alone and supplemented with fusion following the onset of thoracolumbar burst fractures. In addition, we also evaluated the necessity of posterolateral fusion for patients treated with posterior pedicle screw fixation. Methods : From January 2007 to December 2009, 46 consecutive patients with thoracolumbar burst fracture were included in this study. On the basis of posterolateral fusion, we divided our patients into the non-fusion group and the fusion group. The radiological assessment was performed according to the Cobb's method, and results were obtained at immediately, 3, 6, 12 months after surgery. The clinical outcomes were evaluated using the modified Mcnab criteria at the final follow-up. Results : The demographic data and the mean follow-up period were similar between the two groups. Patients of both groups achieved satisfactory clinical outcomes. The mean loss of kyphosis correction showed that patients of both groups experienced loss of correction with no respect to whether they underwent the posterolateral fusion. There was no significant difference in the degree of loss of correction at any time points of the follow-up between the two groups. In addition, we also compared the effect of fixed levels (i.e., short versus long segment) on loss of correction between the two groups and there was no significant difference. There were no major complications postoperatively and during follow-up period. Conclusion : We suggest that posterolateral fusion may be unnecessary for patients with thoracolumbar burst fractures who underwent posterior pedicle screw fixation.

• Journal of Korean Neurosurgical Society
• /
• v.58 no.1
• /
• pp.65-71
• /
• 2015

Objective : Lumbar spinal stenosis is conventionally treated with surgical decompression. However, bilateral decompression and laminectomy is more invasive and may not be necessary for lumbar stenosis patients with unilateral radiculopathy. We aimed to report the outcomes of unilateral laminectomy and bilateral pedicle screw fixation with fusion for patients with lumbar spinal stenosis and unilateral radiculopathy. Methods : Patients with lumbar spinal stenosis with unilateral lower extremity radiculopathy who received limited unilateral decompression and bilateral pedicle screw fixation were included and evaluated using visual analog scale (VAS) pain and the Oswestry Disability Index (ODI) scores preoperatively and at follow-up visits. Ligamentum flavum thickness of the involved segments was measured on axial magnetic resonance images. Results : Twenty-five patients were included. The mean preoperative VAS score was $6.6{\pm}1.6$ and $4.6{\pm}3.1$ for leg and back pain, respectively. Ligamentum flavum thickness was comparable between the symptomatic and asymptomatic side (p=0.554). The mean follow-up duration was 29.2 months. The pain in the symptomatic side lower extremity (VAS score, $1.32{\pm}1.2$) and the back (VAS score, $1.75{\pm}1.73$) significantly improved (p=0.000 vs. baseline for both). The ODI improved significantly postoperatively ($6.60{\pm}6.5$; p=0.000 vs. baseline). Significant improvement in VAS pain and ODI scores were observed in patients receiving single or multi-segment decompression fusion with fixation (p<0.01). Conclusion : Limited laminectomy and unilateral spinal decompression followed by bilateral pedicle screw fixation with fusion achieves satisfactory outcomes in patients with spinal stenosis and unilateral radiculopathy. This procedure is less damaging to structures that are important for maintaining posterior stability of the spine.