• Journal of Korean Neurosurgical Society
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• v.63 no.2
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• pp.210-217
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• 2020

Objective : To analyze the accuracy of iliac screws using freehand technique performed by the same surgeon. We also analyzed how the breach of iliac screws was related to the clinical symptoms resulting in revision surgery. Methods : From January 2009 to November 2015, 100 patients (193 iliac screws) were analyzed using postoperative computed tomography scans. The breaches were classified based on the superior, inferior, lateral, and medial iliac wall violation by the screw. According to the length of screw extrusion, the classification grades were as follows : grade 1, screw extrusion <1 cm; grade II, 1 cm ≤ screw extrusion <2 cm; grade III, 2 cm ≤ screw extrusion <3 cm; and grade IV, 3 cm ≤ screw extrusion. We also reviewed the revision surgery associated with iliac screw misplacement. Results : Of the 193 inserted screws, 169 were correctly located and 24 were misplaced screws. There were eight grade I, six grade II, six grade III, and four grade IV screw breaches, and 11, 8, 2, and 3 screws violated the medial, lateral, superior, and inferior walls, respectively. Four revision surgeries were performed for the grade III or IV iliac screw breaches in the lateral or inferior direction with respect to its related symptoms. Conclusion : In iliac screw placement, 12.4% breaches developed. Although most breaches were not problematic, symptomatic violations (2.1%) could result in revision surgery. Notably, the surgeon should keep in mind that lateral or inferior wall breaches longer than 2 cm can be risky and should be avoided.

• Journal of Korean Neurosurgical Society
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• v.61 no.1
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• pp.75-80
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• 2018

Objective : Among the various sacropelvic fixation methods, S2 alar-iliac (S2AI) screw fixation has several advantages compared to conventional iliac wing screw. However, the placement of S2AI screw still remains a challenge. The purpose of this study was to describe a novel technique of free hand S2AI screw insertion using a K-wire and cannulated screw, and to evaluate the accuracy of the technique. Methods : S2AI screw was inserted by free hand technique in sixteen consecutive patients without any fluoroscopic guidance. The gearshift was advanced to make a pilot hole passing through the sacroiliac joint and directing the anterior inferior iliac spine. A K-wire was placed through the pilot hole. After introducing a cannulated tapper along with the K-wire, a cannulated S2AI screw was installed over the K-wire. Results : Thirty-three S2AI screws were placed in sixteen consecutive patients. Thirty-two screws were cannulated screws, and one screw was a conventional non-cannulated screw. Thirty out of 32 (93.8%) cannulated screws were accurately positioned, whereas two cannulated screws and one non-cannulated screw violated lateral cortex of the ilium. Conclusion : The technique using K-wire and cannulated screw can provide accurate placement of free hand S2AI screw.

• Journal of Korean Neurosurgical Society
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• v.48 no.4
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• pp.347-353
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• 2010

Objective : Iliac screw fixation has been used to prevent premature loosening of sacral fixation and to provide more rigid fixation of the sacropelvic unit. We describe our technique for iliac screw placement and review our experience with this technique. Methods : Thirteen consecutive patients who underwent spinopelvic fixation using iliac screws were enrolled. The indications for spinopelvic fixation included long segment fusions for spinal deformity and post-operative flat-back syndrome, symptomatic pseudoarthrosis of previous lumbosacral fusions, high-grade lumbosacral spondylolisthesis, lumbosacral tumors, and sacral fractures. Radiographic outcomes were assessed using plain radiographs, and computed tomographic scans. Clinical outcomes were assessed using the Oswestry Disability Index (ODI) and questionnaire about buttock pain. Results : The median follow-up period was 33 months (range, 13-54 months). Radiographic fusion across the lumbosacral junction was obtained in all 13 patients. The average pre- and post-operative ODI scores were 40.0 and 17.5, respectively. The questionnaire for buttock pain revealed the following : 9 patients (69%) perceived improvement; 3 patients (23%) reported no change; and 1 patient (7.6%) had aggravation of pain. Two patients complained of prominence of the iliac hardware. The complications included one violation of the greater sciatic notch and one deep wound infection. Conclusion : Iliac screw fixation is a safe and valuable technique that provides added structural support to S1 screws in long-segment spinal fusions. Iliac screw fixation is an extensive surgical procedure with potential complications, but high success rates can be achieved when it is performed systematically and in appropriately selected patients.

• Journal of Korean Neurosurgical Society
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• v.58 no.6
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• pp.578-581
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• 2015

A rigid spino-pelvic fixation to anchor long constructs is crucial to maintain the stability of long fusion in spinal deformity surgery. Besides obtaining immediate stability and proper biomechanical strength of constructs, the S2 alar-iliac (S2AI) screws have some more advantages. Four Korean fresh-frozen human cadavers were procured. Free hand S2AI screw placement is performed using anatomic landmarks. The starting point of the S2AI screw is located at the midpoint between the S1 and S2 foramen and 2 mm medial to the lateral sacral crest. Gearshift was advanced from the desired starting point toward the sacro-iliac joint directing approximately $20^{\circ}$ angulation caudally in sagittal plane and $30^{\circ}$ angulation horizontally in the coronal plane connecting the posterior superior iliac spine (PSIS). We made a S2AI screw trajectory through the cancellous channel using the gearshift. We measured caudal angle in the sagittal plane and horizontal angle in the coronal plane. A total of eight S2AI screws were inserted in four cadavers. All screws inserted into the iliac crest were evaluated by C-arm and naked eye examination by two spine surgeons. Among 8 S2AI screws, all screws were accurately placed (100%). The average caudal angle in the sagittal plane was $17.3{\pm}5.4^{\circ}$. The average horizontal angle in the coronal plane connecting the PSIS was $32.0{\pm}1.8^{\circ}$. The placement of S2AI screws using the free hand technique without any radiographic guidance appears to an acceptable method of insertion without more radiation or time consuming.

• Journal of Korean Neurosurgical Society
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• v.52 no.2
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• pp.120-125
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• 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
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• v.42 no.6
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• pp.495-498
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• 2007

Fractures of lumbo-sacral junction involving bilateral sacral wings are rare. Posterior lumbo-sacral fixation does not always provide with sufficient stability in such cases. Various augmentation techniques including divergent sacral ala screws, S2 pedicle screws and Galveston rods have been reported to improve lumbo-sacral stabilization. Galveston technique using iliac bones would be the best surgical approach especially in patients with bilateral comminuted sacral fractures. However, original Galveston surgery is technically demanding and bending rods into the appropriate alignment is time consuming. We present a patient with unstable lumbo-sacral junction fractures and comminuted U-shaped sacral fractures treated by lumbo-sacro-pelvic fixation using iliac screws and discuss about the advantages of the iliac screws over the rod system of Galveston technique.

• Journal of Korean Neurosurgical Society
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• v.37 no.1
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• pp.39-43
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• 2005

Objective: For Posterior lumbar interbody fusion(PLIF) various cages or iliac bone dowels are used with or without pedicle screw fixation(PSF). To evaluate and compare the clinical and radiological results of different fusion methods, we intend to verify the effect of added PSF on PLIF, the effect of bone cages and several factors which are thought to be related with the postoperative prognosis. Methods: One hundred and ninety seven patients with lumbar spinal stenosis and instability or spondylolisthesis underwent various fusion operations from May 1993 to May 2003. The patients were divided into five groups, group A (PLIF with autologous bone dowels, N=24), group B (PLIF with bone cages, N=13), group C (PLIF with bone dowels and PSF, N=37), group D (PLIF with bone cages and PSF, N=30) and group E (PSF with intertransverse bone graft, N=93) for comparison and analyzed for the outcome and fusion rate. Results: Outcome was not significantly different among the five groups. In intervertebral height (IVH) changes between pre- and post-operation, Group B ($2.42{\pm}2.20mm$) was better than Group A ($-1.33{\pm}2.05mm$). But in the Group C, D and E, the IVH changes were not different statistically. Fusion rate of group C, D was higher than that of Group A and B. But the intervertebral height(IVH) increased significantly in group B($2.42{\pm}2.20mm$). Fusion rate of group C and D were higher than that of group A and D. Conclusion: Intervertebral cages are superior to autologous iliac bone dowels for maintaining intervertebral height in PLIF. The additional pedicle screw fixation seems to stabilize the graft and improve fusion rates.

• Journal of Trauma and Injury
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• v.19 no.2
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• pp.164-172
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• 2006

Background: The authors conducted a retrospective study to evaluate the mechanism of injury, the surgical techniques, the clinical features, the combined injuries, the treatment results, and the surgical complications in patients with atlantoaxial fracture/subluxations. Methods: The authors reviewed 71 cervical fracture/dislocations during a four-year period from September 2002 to August 2006. Among them, there were twenty one C1,2 fracture/subluxations. There were thirteen men (mean age : 43.5 years) and eight women (mean age : 50 years). Their follow-up period was at least 6 months, and the mean follow-up period was 9.6 months. Gardner-Wells tongs traction was used in all patients immediately on presentation. Surgical treatment was performed, depending on the pathologic conditions. Results: Of all 21 cases, 14 cases were injured in motor vehicle accidents, 5 were falls, and 2 were miscellaneous. There were four C1 fracture (5.6%), fourteen C2 fracture (66.7%), one C1 and 2 combined fracture (4.8%), and one C1-2 subluxation (4.8%). The C1 fractures in our series were classified as two Jefferson's fractures and two C1 lateral mass fracture. The C2 fractures were classified as one odontoid type I fracture, two odontoid type II fractures, five odontoid type III fractures, one hangman's fracture, and four C2 body tear-drop fractures. Atlantoaxial fractures were associated with six (28.6%) head injuries, four (19.0%) other spinal injuries, two (9.5%) chest injuries, and three (14.3%) spinal cord injuries. Surgical treatment was performed in nine cases, which included anterior odontoid screw fixation in two cases, transarticular screw fixation with iliac bone graft in one case, posterior fixation by using C2 pedicle screw and C3 lateral mass screw in three cases, lateral mass screw fixation C1-2 with iliac bone graft in one case, O(occipito)-C1-3-4 screw fixation in one case, posterior C2-3 wiring with allograft in one case, and halo vest in six cases. Conservative management was used in the rest of the patients in our trials. Bone fusion was complete in all cases. There were no operation-related complication, except one pin site infection in the case of halo vest. Conclusion: In this study, the choice of appropriate treatment according to the fracture types resulted in safe and effective management of unique atlantoaxial fracture/subluxations.

• Journal of Korean Neurosurgical Society
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• v.37 no.3
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• pp.201-206
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• 2005

Objective: To evaluate the accuracy and safety of C1-C2 transarticular screw insertion, we retrospectively review surgical records and postoperative radiological findings. Methods: From January 2001 to October 2003, the C1-C2 transarticular screw fixation and posterior wiring with iliac bone grafts was performed in 16 patients. 6 patients had rheumatoid arthritis which caused cervical instability, 3 patients had os odontoideum, 3 patients had type 2 odontoid process fracture, 3 patients had traumatic transverse ligament injury and 1 patients who had been managed with C1-C2 wire fixation had psoriatic arthritis. Results: Osseous fusion was documented in 15 patients(93.8%). Only one patient was recorded screw loosening because of postoperative infection. One patient had only one screw placed because of abnormal anatomical structure, one patients was breakage of a Kirschner wire, and one screw was medial location to lateral mass of C1, but clinical results was excellent and radiological instability was not noted. Conclusion: The author's experience demonstrates that C1-C2 transarticular screw fixation with wired bone graft is a safe procedure with higher fusion rate but precaution is needed to avoid the neural damage, vertebral artery injury, and hardware failure.

• Journal of Korean Neurosurgical Society
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• v.29 no.11
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• pp.1469-1475
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• 2000

Objective : The goal of this study was to evaluate the clinical outcome of the posterior C1-2 transarticular screw fixation without C1-2 sublaminar wiring in atlantoaxial instability. Methods : Between Apr. 1995 and Feb. 2000, we used this technique in treat randomly selected 17 patients (11 men, 6 women) who had atlantoaxial instability. The causes of instability were : type II-A odontoid process fracture(10 cases) ; type II-P odontoid process fracture(1 case) ; Os odontoideum(2 cases) ; transverse ligament laxity due to rheumatoid disease(1 case) ; and, transverse ligament injury without bone fracture(3 cases). All cases were operated with posterior C1-2 transarticular screw fixation with 3.5mm cortical screw and interlaminar iliac graft without sublaminar wire fixation. The mean follow-up period was 28 months(5 to 58 months) and the mean age at the time of operation was 41 years(15 to 68 years). All Patients were allowed to ambulate with Philadelphia neck collar on the first post-operation day. Results : Bony fusion was successfully achieved in all cases demonstrated at 3-month follow-up studies. There was no operative mortality or morbidity. Conclusion : The authors conclude that the posterior transarticular screw fixation without C1-2 sublaminar wiring provide adequate stability with high bony union rate in atlantoaxial instability of various causes.