A new method for reduction quality assessment in acetabular fractures: acetabular congruency measurement.

INTRODUCTION: The determination of adequate reduction is difficult perioperatively due to inadequate radiographic scanning and objective measurement methods. The purpose of the present study is to evaluate an objective measurement of the weight bearing acetabular dome congruency. The sensitivity and specificity of 2 measurement methods after acetabular fracture fixation are compared. PATIENTS AND METHODS: Postoperative acetabular reduction was assessed based on postoperative anteroposterior radiographs according to hip joint congruency and Matta's classification in 55 patients. For hip joint congruency measurements, one circle was drawn as superior femoral head border and another one was drawn as weight-bearing acetabular dome border. The difference between the centres of the circles was measured in millimetres. Comparative studies were performed between groups according to reduction quality and clinical and radiological results. RESULTS: The threshold value for the difference between the 2 circle centres was found as 4.4 mm according to the clinical outcomes; 3.8 mm according to radiological outcomes in joint congruency method. The sensitivity of this method was found as 90.2% and 92.7%, and specificity as 64.3% and 57.1% considering the clinical and radiological results, respectively. In the assessment of joint congruency, false positive rate was lower than assessing reduction quality using the method defined by Matta. CONCLUSIONS: Joint congruency assessment based on a postoperative anteroposterior radiograph in patients treated with open reduction internal fixation for acetabular fractures is a suitable method for assessing the adequacy of reduction. This method can be used intraoperatively using fluoroscopy imaging during surgery.

Posteromedial Approach for Osteochondral Lesions of the Talus.

BACKGROUND: Medial malleolar osteotomy is an established procedure for accessing the medial localized osteochondral lesions of the talus. The purpose of this study was to describe a single approach, which allows perpendicular access to the lesion without a malleolar osteotomy. METHODS: Six patients were treated surgically for medial localized talar osteochondral lesions. Four patients had stage III and 2 patients had stage IV lesions. A single posteromedial approach was used for accessing the medial talar dome. RESULTS: The method of treatment was mosaicplasty in 4 patients and osteochondral fragment fixation in 2 patients. One patient who was treated with a fragment fixation procedure showed screw loosening. Incorporation of the osteochondral grafts was proved by magnetic resonance imaging in all mosaicplasty cases. CONCLUSION: A single posteromedial approach was sufficient in the posteromedial localized osteochondral lesion of the talus. As the lesion was approached by soft tissue exposure only, a malleolar osteotomy was not required. Thus, osteotomy-related complications were avoided. LEVEL OF EVIDENCE: Level IV, retrospective case series.

Onychogryphosis.

BACKGROUND: Onychogryphosis is a nail disorder that can damage nail plates, usually caused by repeated minor trauma to the foot. Onychogryphosis of the toe is commonly seen in clinical practice; however, optimal treatment of the condition is still the subject of debate. The purpose of this study was to evaluate clinical outcomes of patients with toe onychogryphosis treated by subcutaneous flap coverage after total matricectomy. METHODS: In this article, we describe 12 patients who had onychogryphosis on the great toe treated by subcutaneous flap coverage after total matricectomy. There were eight men and four women, with a mean age of 63.8 years (range, 56-74 years). RESULTS: The follow-up period ranged from 4 to 108 months, with an average of 25.2 months. All of the flap reconstructions ultimately survived. CONCLUSIONS: The advantage of the described technique is the avoidance of tight closure of the skin and preservation of toe length. The possible limitation of the technique is poor blood circulation to the feet.

Medial approach for the treatment of femur fractures in association with vascular injury.

INTRODUCTION: To highlight an alternative method of treatment for femoral fractures associated with vascular injury, allowing both fracture fixation and vascular repair from the same surgical approach. DESIGN: Retrospective case series. METHODS: Twelve patients with arterial injury as a consequence of femoral fracture were treated by internal fixation. There were five femoral diaphysis, seven distal femoral including supracondylar and intercondylar fractures. Four patients had injury to the popliteal artery, whereas eight to the superficial femoral artery. Seven patients had a nerve injury. Medial femoral approach was used both for the fixation of the fracture and vascular repair. Fracture fixation was done by plate-screw in all patients, whereas vascular injuries were treated using saphenous vein interposition graft in ten patients and end-to-end repair in two patients. Nerve injuries were not dealt by exploration during the vascular repair. RESULTS: All of the limbs were ultimately survived. Clinical and radiological union was observed in all patients at the last follow-up radiographs. Of the 4 total sciatic nerve palsies, 2 had developed total, one had tibial nerve recovery. One patient had no motor recovery. Of the 3 peroneal nerve palsies, 1 patient had recovery, 2 patients had no motor improvement. CONCLUSIONS: A midlateral approach is traditionally used for fractures of femur when plates and screws are used for fixation. In association with vascular injury, this procedure requires two separate incisions. The added soft tissue disruption associated with open reduction and internal fixation by lateral incision can be reduced with the use of single medial approach, which allows bony stabilization under direct visualization of the repaired vessels.

Lateral Transfibular Approach to Tibial Pilon Fractures: A Case Report.

We present a case of tibial pilon fracture where only the lateral part of the distal tibia was affected. The transfibular approach to the ankle was used for the surgical treatment of the fracture. After an initial nonweightbearing period of 3 weeks, full weightbearing was allowed 8 weeks after surgery. The second-year follow-up showed no evidence of degenerative signs, with full ankle range of motion.

BIOMECHANICAL COMPARISON OF MEDIAL VERSUS LATERAL SIDED PLATING IN FEMORAL FRACTURES.

OBJECTIVE: The aim of the present study was to determine whether the side of application of the plate itself affects the mechanical stability of the fixation. The specific question addressed is whether or not a lateral or medial plate application is biomechanically better, for the treatment of distal diaphysis fractures of the femur. METHODS: Stability and stiffness of medial sided plating relative to the conventional lateral sided plating in distal diaphysis of the femur were measured by analyzing axial loading forces leading to implant failure. Sixty synthetic femurs were tested in physiological bending, to calculate the yield and ultimate load to displacement following fixation of distal diaphysis fractures of the femur by either medial or lateral sided plating. Axial loading was applied to samples using a uniaxial testing machine. RESULTS: There was more implant deformation in the lateral sided plating group - a difference with statistical significance. CONCLUSION: Medial sided plating was found to be as stiff as lateral plating. Medial plating may be a reasonable treatment option that can be used safely in selected cases. Level of Evidence I, Therapeutic Studies Investigating the Results of Treatment.

OBJETIVO: O objetivo deste estudo foi determinar se o lado de aplicação da placa em si afeta a estabilidade mecânica da fixação. A questão específica abordada é se a aplicação da placa lateral ou medial é melhor ou não em termos biomecânicos para o tratamento das fraturas da diáfise distal do fêmur. MÉTODOS: A estabilidade e a rigidez da placa medial com relação à lateral, convencional na diáfise distal do fêmur, foram medidas pela análise das forças de carga axial que levam à falha do implante. Sessenta fêmures sintéticos foram testados em flexão fisiológica, para calcular a tolerância e a carga final para o deslocamento após a fixação das fraturas diafisárias distais do fêmur com placa medial ou lateral. A carga axial foi aplicada às amostras usando máquina de teste uniaxial. RESULTADOS: Verificou-se maior deformação do implante no grupo de placa lateral ­ diferença com significância estatística. CONCLUSÃO: Constatou-se que a placa medial era tão rígida quanto a lateral. A placa medial pode ser uma opção de tratamento razoável e segura em casos selecionados. Nível de evidência I, Estudos terapêuticos - Investigação dos resultados do tratamento.

Biomechanical comparison of medial versus lateral sided plating in femoral fractures / Comparação biomecânica de placa óssea medial versus lateral em fraturas do fêmur

ABSTRACT Objective: The aim of the present study was to determine whether the side of application of the plate itself affects the mechanical stability of the fixation. The specific question addressed is whether or not a lateral or medial plate application is biomechanically better, for the treatment of distal diaphysis fractures of the femur. Methods: Stability and stiffness of medial sided plating relative to the conventional lateral sided plating in distal diaphysis of the femur were measured by analyzing axial loading forces leading to implant failure. Sixty synthetic femurs were tested in physiological bending, to calculate the yield and ultimate load to displacement following fixation of distal diaphysis fractures of the femur by either medial or lateral sided plating. Axial loading was applied to samples using a uniaxial testing machine. Results: There was more implant deformation in the lateral sided plating group - a difference with statistical significance. Conclusion: Medial sided plating was found to be as stiff as lateral plating. Medial plating may be a reasonable treatment option that can be used safely in selected cases. Level of Evidence I, Therapeutic Studies Investigating the Results of Treatment

RESUMO Objetivo: O objetivo deste estudo foi determinar se o lado de aplicação da placa em si afeta a estabilidade mecânica da fixação. A questão específica abordada é se a aplicação da placa lateral ou medial é melhor ou não em termos biomecânicos para o tratamento das fraturas da diáfise distal do fêmur. Métodos: A estabilidade e a rigidez da placa medial com relação à lateral, convencional na diáfise distal do fêmur, foram medidas pela análise das forças de carga axial que levam à falha do implante. Sessenta fêmures sintéticos foram testados em flexão fisiológica, para calcular a tolerância e a carga final para o deslocamento após a fixação das fraturas diafisárias distais do fêmur com placa medial ou lateral. A carga axial foi aplicada às amostras usando máquina de teste uniaxial. Resultados: Verificou-se maior deformação do implante no grupo de placa lateral - diferença com significância estatística. Conclusão: Constatou-se que a placa medial era tão rígida quanto a lateral. A placa medial pode ser uma opção de tratamento razoável e segura em casos selecionados. Nível de evidência I, Estudos terapêuticos - Investigação dos resultados do tratamento.

Posterior Malleolus Fractures in Trimalleolar Ankle Fractures: Malleolus versus Transyndesmal Fixation.

BACKGROUND: In ankle fractures involving the posterior malleolus, the issue of which types of fractures require posterior malleolus fixation is still controversial. Recent studies have demonstrated that trimalleolar fractures adversely affect the functional outcomes in comparison to bimalleolar fractures of the lateral and medial malleolus. The purpose of this study was to assess the effects of posterior malleolus fixation on the functional and radiological outcomes. MATERIALS AND METHODS: Reduction quality, development of posttraumatic ankle osteoarthritis, and functional outcomes in 49 consecutive trimalleolar ankle fractures were evaluated retrospectively in patients with and without posterior malleolus fixation. Group I consisted of 29 patients, in which posterior malleolar fracture was left untreated. Twenty patients in Group II, posterior malleolar fragment was fixed directly by screws alone or plate screw. Twenty-one of these 49 patients were male (43%). The mean age was 47 years (range 20-82 years). RESULTS: The mean followup was 12 to 51 months with a mean of 15 months (range 12-51 months). Statistically significant differences were found between Group I and Group II in terms of ankle arthrosis. American Orthopaedic Foot and Ankle Society score was significantly lower in Group I compared to Groups II. CONCLUSIONS: These results demonstrate that posterior malleolar fracture fixation is closely related to successful radiological and functional outcomes after trimalleolar fractures. Transyndesmal screw fixation may not be needed in the cases where the posterior malleolar fracture fixated. For these reasons, we recommend that all posterior malleolar fractures have to be fixed regardless of size.

Surgical treatment of thoracolumbar tuberculosis: a retrospective analysis of autogenous grafting versus expandable cages.

PURPOSE: There has been no uniform and extensive description of the use of expandable cages in the setting of thoracolumbar tuberculosis. The purpose of the study was to evaluate the results of the expandable cages and compare with autogenous strut grafting in thoracolumbar tuberculosis. METHODS: From January 2003 to January 2014, a total of 28 patients with thoracolumbar tuberculosis were treated surgically in our medical center. Patients were divided into three groups. 17 patients received anterior-only surgery; consisting of autogenous iliac bone grafting only in 9 (Group 1), grafting with anterior screw-rod system instrumentation after debridement in 8 patients (Group 2). 11 patients underwent anterior surgery including debridement and distraction of the kyphosis by cages after corpectomy following posterior instrumentation (Group 3).The changes in degree of kyphotic deformity, loss of correction, intervertebral height and loss of intervertebral height were evaluated preoperatively, postoperatively and at the final follow-up. RESULTS: Patients were followed 52 ± 10.7 months (range, 18-120 months). Mean age in the Group 1 was 42 (18-69) years, 62 (19-86) years in the Group 2 and 51 (19-71) years in the Group 3. There was no statistically significant difference (P > 0.05) in the focal kyphosis preoperatively, postoperatively and at the last follow-up between three groups. There were statistically significant differences (P < 0.05) in loss of correction, intervertebral height (preoperative, postoperative and final follow-up) and loss of intervertebral height between three groups. There was a greater loss of correction in Group 1 when compared with Group 2 and Group 3. The difference was statistically significant (p < 0.001). There was no statistically significant difference in the intervertebral height postoperatively and follow-up between Group 1 and Group 2. There was a significant increase in the intervertebral height in Group 3 when compared with Group 1 and Group 2. There was also a significant increase in the intervertebral height in Group 2 when compared with Group 1. There was a greater loss of intervertebral height in Group 1 than in Group 2 and Group 3. The difference was statistically significant (p < 0.001). CONCLUSIONS: Expandable cages are an acceptable surgical option for the treatment of thoracolumbar tuberculosis. Sagittal alignment is better prevented with the expandable cages than anterior grafting with or without anterior instrumentation. Subsidence of the expandable cages is not uncommon and results in the loss of Cobb angle correction and intervertebral height. However, anterior vertebral column reconstruction by expandable cages provides a very high and effective rate of deformity correction and maintenance.

Management of Persistent Cerebrospinal Fluid Leakage Following Thoraco-lumbar Surgery.

STUDY DESIGN: This was a retrospective study of patients who had developed a dural tear after thoracic and lumbar spine surgery that was not recognized during the surgery, and was treated either by lumbar drainage or over-sewing of the wounds. PURPOSE: To revisit the treatment strategies in postoperative dural leaks and present our experience with over-sewing of the wound and lumbar drainage. OVERVIEW OF LITERATURE: Unintended durotomy is a frequent complication of spinal surgery. Management of subsequent cerebrospinal fluid leakage remains controversial. There is no distinct treatment guideline according to the etiology in the current literature. METHODS: The records of 368 consecutive patients who underwent thoracic and/or lumbar spine surgery from 2006 throug h 2010 were retrospectively reviewed. Seven cerebrospinal fluid fistulas and five pseudomeningoceles were noted in 12 (3.2%) procedures. Cerebrospinal fluid diversion by lumbar drainage in five pseudomeningoceles and over-sewing of wounds in seven cerebrospinal fluid fistulas employed in 12 patients. Clinical grading was evaluated by Wang. RESULTS: Of the 12 patients who had a dural tear, 5 were managed successfully with lumbar drainage, and 7 with oversewing of the wound. The clinical outcomes were excellent in 9 patients, good in 2, and poor in 1. Complications such as neurological deficits, or superficial or deep wound infections did not develop. A recurrence of the fistula or pseudomeningocele after the treatment was not seen in any of our patients. CONCLUSIONS: Pseudomeningoceles respond well to lumbar drainage, whereas over-sewing of the wound is an alternative treatment option in cerebrospinal fluid fistulas without neurological compromise.

A comparison of intramedullary nailing and plate-screw fixation in the treatment for ipsilateral fracture of the hip and femoral shaft.

We compared the outcomes of intramedullary nailing with plate-screw fixation in the treatment for ipsilateral fracture of the hip and femoral shaft. A retrospective study. Level 1 Trauma. Forty-one patients (32 males and 9 females; mean age, 34 years; age range, 21-53) with ipsilateral hip and femoral shaft fractures were treated between 1995 and 2005. Eighteen patients were injured in motor vehicle accidents, and 23 fell from a height. All patients were treated by one of the two methods of internal fixation: a screw-plate fixation (n = 24, Group I) or intramedullary nailing (n = 17, Group II). The fracture union time, nonunion, delayed union, implant failure, need of further surgeries, and functional outcomes were investigated and compared. Fisher's exact test showed that Group I had a significantly higher frequency of nonunion than that of Group II (P = 0.029). Although Group I had more nonunions, delayed unions, and revision operations than Group II, the total union time was similar for both groups. Intramedullary nailing was found to be superior to screw-plate fixation due to improved functional bearing, increased rate of union, stability, and mechanical solidity. The reconstruction nail method is an acceptable alternative treatment for ipsilateral hip and femoral shaft fractures.

Isolated avulsion fracture of lesser tuberosity of the humerus: Review of the literature and report of two cases.

Two cases of acute isolated avulsion fracture of the lesser tuberosity of the humerus and their short-term outcome are presented with a review of previously reported cases. Open reduction and internal fixation was performed. Outcomes were excellent, and the patients regained their normal pain-free shoulder function 3 months after the operation. This was a Level IV study.

Spontaneous osteonecrosis of the tarsal navicular in an adult: Mueller-Weiss syndrome.

Spontaneous osteonecrosis of the navicular in the adult is known as Mueller-Weiss syndrome, which is a rare disease characterized by a collapse of the lateral portion of the tarsal navicular combined with a medial protrusion of the talar head and peri-navicular osteoarthritis. In this article, we describe a case of spontaneous osteonecrosis of tarsal navicular in a 43-year-old male. Chronic midfoot pain over the dorsomedial aspect of the right foot was resolved after complete removal of the necrotic bone from the tarsal navicular, followed by an autologous bone grafting of the resultant defect.

Radiographic features of the Lenke 1A curves to help to determine the optimum distal fusion level selection.

STUDY DESIGN: Retrospective study. OBJECTIVE: Investigate the radiographic features of the subtypes of Lenke 1A curves to help to determine the optimum distal fusion level selection. SUMMARY OF BACKGROUND DATA: The Lenke 1A was the most frequently evaluated curve type in adolescent idiopathic curves. Miyanji et al suggested that the lumbar modifier type A does not accurately define the behavior of the compensatory lumbar curve in Lenke 1A. The tilt of L3 and L4 in the coronal plane may have a significant role in determining distal fusion level. METHODS: Thirty-six patients with Lenke type 1A idiopathic scoliosis treated by segmental posterior instrumentation with an average of 52.1-month follow-up were retrospectively analyzed. Four different curve types depending on L3-L4 vertebral tilt were described. The radiographic measurements including proximal and distal junctional kyphosis was obtained at latest follow-up. RESULTS.: Preoperative mean major curve Cobb angle of 47.6° was corrected to 12.9° showing a correction rate of 72.8% and maintained at 14.2°. Loss of correction at final follow-up was 2.7%. The mean compensatory curve Cobb angle of 24.4° was corrected to 8.2°. All patients balanced after surgery although seven had more than -5° clavicle angle before surgery. The mean preoperative and postoperative sagittal T5-T12 angles were 30.6° and 26.2°, respectively, and 29.1° at latest follow-up. The mean preoperative, postoperative, and latest follow-up T10-L2 sagittal Cobb angles were -0.2°, 2.0°, and 4.2°. Three patients diagnosed as distal junctional kyphosis at latest follow-up. CONCLUSION: Distal fusion level should be extended to at least lower end vertebra (LEV) -1 in type 1A-A and type 1A-D curves, while it might be necessary to go down to LEV in the type 1A-B and 1A-C. It seems that LEV might be a reliable guide to select ideal distal fusion level in Lenke type 1A curves.

Boyd amputation in adults.

BACKGROUND: Foot ulcerations resulting in amputation are one of the most devastating consequences of diabetes mellitus and peripheral arterial disease. In foot amputations, Boyd amputation has been even less accepted than Syme amputation due to its dependence on calcaneotibial osseous union in adults. METHODS: Fifteen Boyd amputations were performed for 14 adults. The indications for amputation were diabetic ulceration of the foot in eight patients, ischemic disease of the lower extremity in four and salvage of the deformed foot due to peripheral neuropathy in one patient. One patient with scleroderma had bilateral amputations due to digital ischemic necrosis. RESULTS: Complete wound healing was documented in seven feet of six patients. Further revisions to a more proximal amputation level were required in seven patients. CONCLUSION: Despite the high failure rate, we believe Boyd amputation is still a good option in some patients to try to preserve length.

Operative treatment of hip fractures in patients receiving hemodialysis.

Fifteen hips in 13 patients with hip fracture were treated in patients receiving hemodialysis for chronic renal failure. There were four intertrochanteric and 11 femoral neck fractures. 10 of the 11 femoral neck fractures and one of the four intertrochanteric fractures were treated with cemented bipolar hemiarthroplasty. Two intertrochanteric fractures fixed with sliding compression screws. External fixation was used for stabilization in two patients who had femoral neck and intertrochanteric fractures. Two intertrochanteric fractures that were treated with sliding hip screw showed radiological union postoperatively at the 6th month. Of the 11 hemiarthroplasty, four hips developed aseptic loosening (36%). According to Harris hip score grading system, three (37.5%) poor, two (25%) fair, two (25%) good and one (12.5%) case had excellent outcome in the hemiarthroplasty group. The survival of dialysis patients with a hip fracture is markedly reduced. Initial treatment of hemiarthroplasty allows early mobilization and prevents revision surgery.

Isolated pedicle screw instrumented correction for the treatment of thoracic congenital scoliosis.

STUDY DESIGN: Retrospective study. OBJECTIVE: To evaluate the radiologic results of fusion with segmental pedicle screw fixation in neglected thoracic congenital curves with a mean follow-up of 51.3 months (range: 24 to 108 mo). SUMMARY OF BACKGROUND DATA: Segmental pedicle screw fixation has been shown to be effective both in correcting and controlling the idiopathic spinal deformities. However, the choice of treatment modality is more controversial in neglected thoracic congenital curves of the aged. METHODS: Fourteen patients with thoracic congenital curves treated by segmental pedicle screw fixation and fusion were analyzed. The average age of the patients was 14.9 years (range: 10 to 25 y) at surgery. Deformity correction was achieved by compression of the convex deformity side with resection of apical 3 ribs. Radiologic analyses of coronal and sagittal plane included Cobb angles of the major compensatory curves, apical vertebrae translation, and sagittal Cobb angles, respectively. RESULTS: In the coronal plane, the preoperative mean major curve Cobb angle of 52.3 degree (range: 32.6 to 66.7 degrees) was corrected to 25.3 degree (range: 7.2 to 44.8 degree) and the mean compensatory curve Cobb angle of 23.6 degree (range: 10.3 to 34.8 degrees) was corrected to 15.9 degree (range: 5.7 to 30.6 degrees). The mean translation of apical vertebrae was 28.8 mm (range: 4.7 to 53.6 mm) before surgery and 15.5 mm (range: 2.4 to 41.3 mm) after surgery. In the sagittal plane, the mean preoperative and postoperative sagittal T5 to T12 angles were 34.8 degree (range: 16.5 to 44.7 degrees) and 27.3 degree (range: 10.4 to 43.5 degrees), respectively. The mean preoperative and postoperative sagittal T12 to S1 angles were 47.2 degree (range: 23.4 to 65.1 degrees) and 41.3 degree (range: 23.8 to 62.7 degrees), respectively. CONCLUSION: In the neglected thoracic congenital deformities of the aged, with posterior pedicle instrumented fusion, an acceptable correction can be achieved with relatively low morbidity.

Distraction osteogenesis is inhibited by cancer radiotherapy with Co 60.

AIM: To investigate the effects of radiotherapy on distraction osteogenesis performed on the same bone in an area that has not received radiation. Radiotherapy (Co60) was carried out in a region where tumors may develop, and then, on the assumption that the tumoral region had been removed, distraction osteogenesis was carried out, and the effects were investigated. METHOD: Thirty New Zealand rabbits were randomized into two groups, a study group (15 rabbits) and a control group (15 rabbits). In the study group, Co60 was administered by teletherapy to the distal half of the left tibia. Rabbits in the control group were kept in the same environment for the same period, but were not subjected to radiotherapy. Four weeks after radiotherapy, osteotomy was performed on the proximal part of the left tibia of all subjects, and distraction was carried out until 10mm. After distraction was completed, the outcomes were evaluated radiologically, scintigraphically, and histopathologically, and the results were compared. RESULTS: New bone formation achieved through distraction osteogenesis in the study group animals was inadequate, while new bone tissue achieved in the control group was superior (P < 0.001). CONCLUSION: Radiotherapy has a negative effect on distraction osteogenesis, even if performed on a different part of the bone.

An unusual type of lateral compression injury of the pelvis tilt fracture with anterior displacement.

Tilt fracture is the most unusual variant of pelvic lateral compression injury. The major problem was reported to be protrusion of the pubic ramus into the perineum by posterior-inferior displacement of the fragment. Tilt fragment with anterior and inferior displacement has not been reported in English speaking literature to our knowledge. Anterior tilt fragment can cause significant morbidity in terms of vascular injury, pelvic stability and acetabular fracture.

Evaluation of thoracic pedicle screw placement in adolescent idiopathic scoliosis.

Pedicle screw fixation is a challenging procedure in thoracic spine, as inadvertently misplaced screws have high risk of complications. The accuracy of pedicle screws is typically defined as the screws axis being fully contained within the cortices of the pedicle. One hundred and eighty-five thoracic pedicle screws in 19 patients that were drawn from a total of 1.797 screws in 148 scoliosis patients being suspicious of medial and lateral malpositioning were investigated, retrospectively. Screw containment and the rate of misplacement were determined by postoperative axial CT sections. Medial screw malposition was measured between medial pedicle wall and medial margin of the pedicle screw. The distance between lateral margin of the pedicle screw and lateral vertebral corpus was measured in lateral malpositions. A screw that violated medially greater than 2 mm, while lateral violation greater than 6 mm was rated as an "unacceptable screw". The malpositions were medial in 20 (10.8%) and lateral in 34 (18.3%) screws. Medially, nine screws were rated as acceptable. Of the 29 acceptable lateral misplacement, 13 showed significant risk; five to aorta, six to pleura, one to azygos vein and one to trachea. The acceptability of medial pedicle breach may change in each level with different canal width and a different amount of cord shift. In lateral acceptable malpositions, the aorta is always at a risk by concave-sided screws. This CT-based study demonstrated that T4-T9 concave segments have a smaller safe zone with respect to both cord-aorta injury in medial and lateral malpositions. In these segments, screws should be accurate and screw malposition is to be unacceptable.