Purpose: We describe a technique using orthoganol imaging on a radiolucent table that allows reliable, safe and reproducible insertion of thoracic pedicle screws. Method: The popularity of pedicle screws for spinal fixation in deformity surgery has increased. Studies have shown lumbar pedicle screws to be safe and effective. The biomechanical superiority of pedicle screws has also been demonstrated. Nonetheless, reluctance to apply the technique to thoracic vertebra remains, most likely because of perceived technical difficulties and a reported high complication rate. We describe a technique using orthoganol imaging on a radiolucent table, used in a series of patients in whom we have inserted a total of over 2000 screws. Results: We have inserted over 2000 thoracic pedicle screws without neurological injury. In addition, this technique has allowed us to use pedicle screw to the exclusion of other, less mechanically favourable, methods of fixation to the spine; over the same time period we used only three sublaminar hooks. Furthermore, the lateral to medial or ‘toeing in’ of screw placement gives greater pull out strength to each screw by increasing the ‘volume’ of bone that has to be overcome before failure by pull out occurs. In addition this trangulation technique allows insertion of :screws of greater diameter than the pedicle and decreases the chance of broaching medially. Conclusion: Using the technique described, we achieve accurate screw placement ‘first time, every time’, giving us a biomechanically superior construct, allowing more powerful derotation of the spine and thus greater correction of deformity. We recommend its use for all thoracic pedicle screws

We prospectively studied the use of intercostal EMG monitoring as an indicator of the accuracy of the placement of pedicle screws in the thoracic spine. We investigated 95 thoracic pedicles in 17 patients. Before insertion of the screw, the surgeon recorded his assessment of the integrity of the pedicle track. We then stimulated the track using a K-wire pedicle probe connected to a constant current stimulator. A compound muscle action potential (CMAP) was recorded from the appropriate intercostal or abdominal muscles. Postoperative CT was performed to establish the position of the screw. The stimulus intensity required to evoke a muscle response was correlated with the position of the screw on the CT scan. There were eight unrecognised breaches of the pedicle. Using 7.0 mA as a threshold, the sensitivity of EMG was 0.50 in detecting a breached pedicle and the specificity was 0.83. Thoracic pedicle screws were accurately placed in more than 90% of patients. EMG monitoring did not significantly improve the reliability of placement of the screw

Introduction. The use of thoracic pedicle screws for the treatment of adolescent idiopathic scoliosis (AIS) has gained widespread popularity. Many techniques has been described to increase the accuracy of free hand placement; however the placement of pedicle screws in the deformed spine poses unique challenges because of possible neurologic and vascular complications. We are describing a universal way of insertion of pedicle thoracic screws which has been applied in many pathologies including the deformed spine. Methods. Our technique includes exposure of the superior facet of the corresponding body to identify its lateral border border which together with the superior border of the TP denotes our entry point which is just lateral to this crossing, we make a short entry with a straight Lenke probe then continue the track with a strong ball probe to go safely through the cancellous bone of the body. This is retrospective review of radiographs and clinical notes of all the patients who underwent posterior thoracic instrumentation by pedicle screws using the same single technique by one surgeon between June 2008 and December 2009; 1653 screws in 167 consecutive patients (119 females and 48 males). There were 139 deformities, 130 scoliosis (AIS 80, Congenital 31, Neuromuscular 10 and Degenerative 9), 19 kyphosis and 18 other diagnoses (fractures 14, revision 3 and tumour 1). Results. The recorded complications for all the patients were: 1 patient had pain due to nerve impingement, 1 parasthesia and 1 CSF leak intraoperatively. There were no revision of any of the screws, no vascular complications. Conclusion. Thoracic pedicle screws can be inserted with a universal point of entry using the same technique in all the levels of the dorsal spine. This technique seems to be simple and safe. Ethics approval: None. Interest Statement: None

Introduction. A new triggered electromyography test for detection of stimulus diffusion to intercostal muscles of the contralateral side during thoracic pedicle screw placement was evaluated. Experimental research was carried out in order to determine if, using this test, neural contact at different aspects of the spinal cord and nerve roots could be discriminated. Methods. Nine industrial pigs (60–75 kg) had 108 pedicle screws placed bilaterally in the thoracic spine (T8–T13). Neural structures were stimulated under direct vision at different anatomic locations from T9 to T12. Recording electrodes were placed over the right and left intercostal muscles. Increasing intensity of the stimulus was applied until muscle response was detected at the contralateral side (diffusion phenomenon). After this first experiment, the thoracic spine was instrumented. Screws were placed in the pedicle in two different positions, the anatomic intrapedicular location and with purposeful contact with the neural elements. Results. Response thresholds to direct stimulation of nerve root at different points were significantly lower than those obtained by stimulation of the dorsal aspect of the spinal cord (0.44±0.22 mA vs 1.38±0.71 mA). However, a 24-fold stimulation intensity (6.50±0.29 mA) was necessary to obtain diffusion of the EMG response to the opposite left side if the right nerve root was stimulated. Only a 2-fold increment (3.17±0.93 mA) was able to elicit diffusion of EMG responses to the contralateral side when stimulation was applied to the dorsal aspect of the spinal cord. Contralateral EMG responses after high increases of stimulation thresholds indicated nerve root contact. Diffusion phenomenon after low threshold increments reflected medullar contact. Electromyography recordings after triggered stimulation of the screws showed that only screws in contact with the spinal cord had significantly lower responses (2.72±1.48 mA). Conclusion. Stimulus-triggered EMG could only discriminate screws with violation of the medial pedicle wall if they were contact with neural tissues. Recording EMG-potentials at the contralateral paraspinal muscles (stimulus diffusion phenomenon) proved to be a reliable method to discriminate which of the neural structures was at risk

Study Design: A radiographic study using disarticulated cadaver thoracic vertebrae. Objective: To determine the accuracy of orthogonal X-rays in detecting thoracic pedicle screw position by different groups of observers. Summary of Background Data: Pedicle screws are increasingly being used for internal fixation of the thoracic spine. Surgeons and radiologists are often required to make decisions on the pedicle screw position by plain antero-posterior (AP) and lateral radiographs. Materials and Methods: 23 disarticulated fresh adult thoracic vertebrae were used in this study. Pedicle screws were inserted completely within the pedicle; or deliberately violating the lateral or medial cortex of the pedicle. AP and lateral radiographs of each vertebrae were assessed by 2 spine surgeons, 2 spine trainees, and 2 musculoskeletal radiologists in a sequence of AP alone, and AP + lateral views. They were supposed to cataogorize the pedicular screw as ‘out laterally’/‘inside the pedicle’/‘out medially’ or ‘unsure’. Their assessments were compared to the actual position of the screws determined by the axial views. Results: For each screw position, trend was found towards slightly better accuracy with availability of AP & lateral views in combination. From either AP alone or AP + lateral views, significantly higher accuracy was found in detecting screws “out laterally” than “inside pedicle” (p< 0.01), or “out medially”(p< 0.05), respectively. Nearly 30% of screws that were deliberately placed through the medial pedicle wall were not correctly identified. In addition, surgeons have highest accuracy from either AP alone, or AP + lateral views, followed by the spine trainees and radiologists. Radiologists provided more “unsure” answers than surgeons or trainees. Conclusions: Screws that perforated the lateral cortex were the easiest, and those that were wholly within the pedicle were the most difficult to identify correctly. The use of plain radiographs to detect thoracic pedicle screws placed through the critical medial cortex is unreliable. The positions of thoracic pedicle screws appear to be more accurately detected by AP + lateral, however, the major contribution was from AP views. Surgeon experience continues to be vitally important in the safe placement of thoracic pedicle screws. Key points:. Screws that perforated the lateral cortex were the easiest, and those that were wholly within the pedicle were the most difficult to identify correctly. The use of plain radiographs to detect thoracic pedicle screws placed through the critical medial cortex is unreliable. AP + lateral views provides higher accuracy in determining the screw position, while, the major contribution comes from AP views. Surgeon experience, in the use of tactile skills and anatomical knowledge continue to be vitally important in the safe placement of thoracic pedicle screws

Aims: Pedicle screws are mechanically superior to conventional fixation techniques in the thoracic spine, but because of safety concerns their use have been limited and rejected by many surgeons on anatomical grounds. Aims of this lecture are to present a literature review and an audit of our own experience. Methods: The recent literature was reviewed to find anatomical and biomechanical studies and clinical reports. Records of patients at our department, where thoracic pedicle screws have been used since 1996 for trauma, tumour, deformity and infection cases were examined for complications related to instrumentation. Results: All biomechanical studies show superior performance of thoracic pedicle screws in comparison to hooks, sublaminar wires or anterior screw constructs. Some cadaver and CT studies show that placement of pedicle screws may cause serious injury to neurovascular structures. However, clinical reports from different institutes around the world show a low complication rate directly related to the use of thoracic pedicle screws. In our own patient population we did not find any serious neurovascular complications, either. Three times, CSF leakage during screw placement was reported without further consequences. No neurologic deficits or injury to major blood vessels have been seen. Conclusions: Despite the theoretical risks it seems that pedicle screws can be placed safely in the majority of thoracic vertebrae even in scoliotic deformities. Thorough knowledge of thoracic spine anatomy and extensive experience with lumbar and thoracolumbar junction pedicle screw placement is necessary to prevent possible devastating complications

Introduction. Thoracic pedicle screws have been proven to be safe and effective in the treatment of adolescent idiopathic scoliosis (AIS). However, the effect of the instrumentation alloy has not yet been investigated. We aimed to compare segmental versus non segmental thoracic pedicle screw instrumentation in patients with AIS. Methods. A consecutive series of 143 patients with AIS (Lenke classification 1–4) surgically treated from 1998 to 2005 by means of thoracic pedicle screws were retrospectively reviewed. Considering implant density (number of fixation anchors placed per available anchors sites; segmental =60% [S], non-segmental =60% [NS]) and implant alloy used (titanium [Ti] vs stainless steel [SS]) we divided the cohort into four groups: Ti-S (48 cases); Ti-NS (34 cases); SS-S (35 cases); and SS-NS (26 cases). Groups were similar for preoperative mean age, sex distribution, Risser sign, main thoracic curve, and thoracic kyphosis. Pearson correlation coefficient and univariate analysis of variance were used. Results. At a mean follow-up of 6·2 years (range 3–10) the overall final main thoracic curve correction was a mean of 61·4% (20–89), whereas the implant density within the major curve was 71% (15–100%). We recorded a significant correlation between implant density and percentage major curve correction (r=0·41, p<0·002); when the four groups were compared we noted that the SS-S group showed the greatest average correction (75%), followed by the Ti-S, SS-NS, and Ti-NS groups. We detected no significant differences between SS-S versus Ti-S versus SS-NS (r=0·002, p>0·05; r=0·13, p>0·05; r=0·07, p>0·01, respectively), whereas the Ti-NS group showed a statistically significant inferior percentage correction when compared with all other groups (average 52%; p<0·001). Nevertheless, no significant difference between groups was recorded on the SRS-30 assessment, showing a postoperative improvement in both self-image and satisfaction. Conclusions. When an SS instrumentation is used, non-segmental pedicle screw constructs seem to be equally effective as segmental instrumentations in obtaining satisfactory results in patients with main thoracic AIS. When the implant alloy used is titanium, an implant density of greater than 60% should be guaranteed so as to achieve similar results to those recorded in this study

Introduction Thoracic pedicle screws are increasingly being used for internal fixation. Surgeons and radiologists are often required to make decisions about the position of the screws in relation to the pedicle based on AP and lateral plain radiographs alone. We ventured to assess the value of orthogonal radiographs in determining the position of thoracic pedicle screws in 23 cadaveric thoracic vertebrae. Methods Disarticulated cadaveric thoracic vertebrae were used in this study. Pedicle screws were inserted in three positions: 1) within the pedicle, deliberately violating the 2) lateral cortex of the pedicle and 3) medial cortex of the pedicle. AP (antero-posterior) & lateral radiographs were obtained and presented to 6 readers (4 surgeons & 2 radiologists) in booklets consisting of AP views alone, lateral views alone and both AP & lateral views together in a sequential manner. The readers were asked to indicate the position of the screws and the results of the evaluation were compared to the actual position (axial views). Results On AP views alone, the accuracy in detecting screws placed out of the pedicle laterally and medially were 93% and 76% respectively, while the accuracy for screws placed inside the pedicle was 85% . On LATERAL views alone, the accuracy for the same screw positions were 69%, 58% and 64% respectively. When AP + LATERAL views were considered together, the accuracy for the same screw positions were 93%, 80% and 87% respectively. Comparing the three groups, it was observed that screw positions were read more accurately in AP + LATERAL views (87%) compared to AP views alone (85%), or LATERAL views alone (64%). The sensitivity of correctly identifying screws placement is highest in AP + LATERAL (90%) views with a specificity of 94%. The specificity of detecting screws placed inside the pedicle is highest in AP (94%). The positive predictive value (PPV) of radiographs in general (AP +LATERAL) in detecting screws placed inside the pedicle, out of the pedicle laterally and medially were 73%, 92% and 86% respectively. The negative predictive value (NPV) of radiographs in general for the same screw locations were 90%, 96% and 76% respectively. On AP and AP + LATERAL views respectively, 25% and 23% of screws placed inside the pedicle were read as medially ‘out’. 10% of screws placed medially ‘out’ were read as ‘in’ on both AP and AP + LATERAL views. Inter-observer difference was substantial. In general, surgeons appeared to have consistently higher accuracy, sensitivity, specificity, PPV and NPV values compared to radiologists and fellows in determining screw position. Discussion The positions of the screws appear to be most accurately detected when both AP and lateral x-rays are provided compared to AP or lateral alone. Screws that perforated the lateral cortex were the easiest and those that were medially out were the most difficult to identify. Screws passed inside the pedicle may create an unnecessary apprehension that they may be medial and screws passed medially may give a false sense of security that the screw is inside the pedicle. Radiographs are just one component in ensuring accurate pedicle screw placement and surgeon’s experience, in the use of tactile skills and anatomical knowledge continue to be vitally important in the safe placement of thoracic pedicle screws

Introduction: We report the result of cervical osteotomy in 11 patients using a controlled reduction technique and assess the safety and efficacy of this operation. Methods: Between 1993 and 2006, 11 patients with ankylosing spondylitis underwent correction of cervical kyphosis utilizing an extension osteotomy at the C7/T1 junction. The procedure was carried out under general anaesthesia with spinal cord monitoring. Lateral mass screws were placed from C3–C6 and thoracic pedicle screws placed from T2 to T5. After completion of the osteotomy, the reduction manoeuvre was carried out by the senior surgeon lifting the halo, while bilateral temporary malleable rods (fixed to cervical lateral mass screws) were allowed to pass through top loading thoracic pedicle screws, before tightening by the assistant when the desired position had been achieved. The temporary malleable rods were then replaced with definitive rods, thereby creating a solid internal fixation. A halo vest was maintained for 12 weeks to support the instrumentation and allow the fusion mass to develop. Results: Surgery was performed on 10 males and one female. The mean age at surgery was 56 years (range 40–74). Duration of symptoms averaged 2.7 years (range 1–5 yrs). The average duration of surgery was 4.7 hours (range 3–6.5) with a mean blood loss of 1938cc (range 1000–3600). The mean follow up was 6.5 years (range 2–13). The mean pre-op chin brow vertical angle was 54º (range 20–70) reducing to 7º (range 2–20) at final follow-up. The mean pre-operative kyphotic angle was 19.2º reducing to minus 34º at final follow up. Restoration of normal forward gaze was achieved in all cases. No patient suffered spinal cord injury or permanent nerve root palsy. Conclusion: Cervico-thoracic osteotomy is a potentially hazardous procedure. The technique described reduces the risk of translation during the reduction manoeuvre thereby reducing the risk of serious neurological injury

Objective: To emphasize the need to provide a controlled method of intra-operative reduction to correct fixed cervical flexion deformities in ankylosing spondylitis and to describe the technique involved. Design: The treatment of severe fixed cervical flexion deformity in ankylosing spondylitis represents a challenging problem that is traditionally managed by a corrective cervicothoracic osteotomy. The authors describe a method of controlled surgical reduction of the deformity, which eliminates saggital translation and reduces the risk of neurological injury. Subjects: 2 male patients aged 39 and 45 years old with ankylosing spondylitis presented with severe fixed flexion deformity of the cervical spine. Both patients had previously undergone a lumbar extension osteotomy to correct a severe thoracolumbar kyphotic deformity. As a result of the fixed cervical flexion deformity, marked restriction in forward gaze with ‘chin on chest’ deformity, feeding difficulties and personal hygiene were encountered in both. Their respective chin-brow to vertical angle was 60 and 72°. Somatosensory and motor evoked potentials were used throughout surgery. A combination of cervical lateral mass screws and thoracic pedicle screws were used. Interconnecting malleable rods were then fixed at the cervical end, thereby allowing them to slide through the thoracic clamps thus achieving a safe method of controlled closure of the cericothoracic osteotomy. When reduction was achieved, definitive pre-contoured titanium rods were interchanged. Halo-jacket was not considered necessary in view of the segmental fixation used. Results: Good anatomical reduction was achieved, with near complete correction of the deformities, restoration of saggital balances and forward gazes. There were no neurological deficits in either patient and the postoperative recoveries were uneventful. Both osteotomies united with no deterioration noted at 2 years. Conclusions: We illustrate a controlled method of surgical reduction during corrective cervicothoracic osteotomy of fixed cervical kyphosis in ankylosing spondylitis. This has been achieved with the use of a combination of cervical lateral mass screws and thoracic pedicle screws with interconnecting malleable rods that were later replaced with titanium rods. The authors believe that the unique technique described remains a technically demanding but adequate and safe approach for correcting such challenging deformities

Background: To describe – Forced traction radiographs under GA for operative planning; The use of segmental orthogonal image-intensification for screw insertion in thoracic & lumbar pedicles; An audit of X-ray exposure during these procedures; The use of multiple Chevron osteotomies as an alternative to anterior release; The correction of scoliosis with convex cantilever, Cotrel-Debousset manoeuvre, segmental translation, segmental rotation,” lumbar-levelling”. Methods: We present our operative technique in addressing deformity. This represents an eclectic evolution, which we feel is sufficiently dissimilar to current standards to merit presentation. Pedicle screws are inserted at multiple levels with no recourse to hook or wires. Five reduction techniques are used and repeated. Results: The complications of 1500 thoracic pedicle screws; the predictive value of forced traction films under GA; the Fulcrum Bending Correction Index and operative parameters of our series are submitted separately. Conclusion: We commend consideration of some or all of our techniques to the society

The aim of the study was to assess the safety of a novel anatomical landmark in the placement of thoracic pedicle screws. It is our clinical observation that the sagittal plane of the screw trajectory is perpendicular to the plane of the superior articular facet, when the entry point is in the lateral half of the articular surface of the corresponding superior facet. Using SECTRA software on a PACS digital imaging system, morphometric analysis was performed on thoracic vertebrae imaged using computed tomography (CT). For inclusion, the scan had to have no reported bony abnormality. It was determined whether a trajectory as described at 90 degrees to the articular facet, with an entry point just caudal to the lateral half of the facet to a depth of 25mm would breach either the medial wall of the pedicle or lateral vertebral body wall anterior to the costovertebral facet. Sixty-two CT scans (744 segments, 1488 pedicle-facet complexes) were reviewed. 1154 complexes were suitable for full analysis. Exclusions were due to the lumbarisation of the T12 facet joints (62) or inability to clearly define the facet surface due to the plane of the CT slice (272). Of 1154 entry points assessed, 1154 (100%) were safe to be entered at 90 degrees to a depth of at least 25mm. We have demonstrated the safety and reliability of a novel anatomical landmark in normal thoracic pedicles. We believe this will improve sagittal plane alignment and reduce further the risk of medial pedicle breach

Study design. Retrospective study. Objectives. To optimise the radiation doses and image quality for the cone-beam O-arm surgical imaging system in spinal surgery. Summary of Background. Neurovascular compromise has been reported following screw misplacement during thoracic pedicle screw insertion. The use of O-arm with or without navigation system during spinal surgery has been shown to lower the rate of screw misplacement. The main drawback of such imaging surgical systems is the high radiation exposure. Methods. Chest phantom and cadaveric pig spine were examined on the O-arm with different scan settings: two were recommended by the O-arm manufacturer (120 kV/320 mAs, and 120 kV/128 mAs), and three low-dose settings (80 kV/80 mAs, 80 kV/40 mAs, and 60 kV/40 mAs). The radiation doses were estimated by Monte Carlo calculations. Objective evaluation of image quality included interobserver agreement in the measurement of pedicular width in chest phantom and assessment of screw placement in cadaveric pig spine. Results. The effective dose/cm for 120 kV/320 mAs-scan was 13, 26, and 69 times higher than those delivered with 80 kV/80 mAs, 80 kV/40 mAs, and 60 kV/40 mAs-scans, respectively. Images with 60 kV/40 mAs were unreliable. Images with 80 kV/80 mAs were considered reliable with good interobserver agreement when measuring the pedicular width (random error 0.38 mm and intraclass correlation coefficient 0.979) and almost perfect agreement when evaluating the screw placement (κ-value 0.86). Conclusions. The radiation doses of the O-arm system can be reduced 5–13 times without negative impact on image quality with regard to information required for spinal surgery

Purpose: To introduce our new surgical technique for better correction of scoliosis and rib hump deformity. Surgical technique: The technique consists of rib mobilization (RM) and hook rotation maneuver (HRM). RM is to release costo-vertebral connection bilaterally from T5 to T10 to mobilize ribs obtaining more flexibility of the spine. HRM is to rotate convex side hooks on transverse process ventrally pushing down the ribs, thus giving derotational force while compression force is applied. Subjects: Forty-six idiopathic cases with minimum 1 year follow-up were reviewed. The average F-up period is 15.1m( 12 – 24). The average age at surgery was 20.1 y(12–57). Conventional multiple hooks, screws, wires and rod system was used. Results: The average Cobb angle was 56.0 ( 40 – 93) degrees. The average rib hump was 22.5 mm in height and 13.9 degrees by scoliometer. At 3 w post-op, 6 m post-op, and at F-up, the average Cobb angle was 13.0 (77.9%), 15.6 (73.4%), and 16.0 (72.6%, 43 – 100%)) respectively. The average rib hump at 6m post-op and at F-up was 9.7 mm in height and 6.8 degrees, and 10.3mm and 6.4 degrees respectively. The hump index at thoracic level was 5.49 pre-op, 3.73 at 6m and 4.25 at F-up. Conclusion: Our new technique improved the correction of not only scoliosis but also thoracic hump significantly. The derotational force by HRM is weaker than direct derotation by pedicle screw. However, it is undoubtedly a safer and less expensive technique than thoracic pedicle screw, providing significant correction of rib hump

Introduction: Several studies have looked at accuracy of thoracic pedicle screw placement, both in vivo and on cadavers, using fluoroscopy, image guidance, and anatomical landmarks. To our knowledge the upper thoracic spine (T1-T6) has not been specifically studied in the context of screw insertion and placement accuracy without the use of either image guidance or fluoroscopy. Our objective was to study the accuracy of placement of upper thoracic screws without the use of fluoroscopy, and report on implant related complications. Methods: A single surgeon inserted a total of 60 screws in 13 consecutive non-scoliotic spine patients. These 60 screws were the first to be placed in the high thoracic spine in our institution. All previous surgeries used only a hook or wire technique for the upper thoracic spine. The most common diagnosis in our patient population was trauma. All screws were inserted using a modified Roy-Camille technique. Post operative axial computed tomography (CT) images were obtained for each patient and analyzed by an independent senior radiologist for placement accuracy. Furthermore we reviewed the operative records of each patient to record any implant related complications. Results: No pedicle screw misplacements were found in 61.5% of the patients. Fifty three out of the 60 screws were placed correctly within all the pedicle margins. The overall pedicle screw placement accuracy was 88.3% using our modified Roy-Camille technique. Five medial and 2 lateral violations were noted in the 7 misplaced screws. One of the 7 misplaced screws was considered to be a marginal violation. No implant related complications were noted. Furthermore, no learning curve effect was noted as far as misplacement pattern was concerned. Conclusion: We found that inserting pedicle screws in the upper thoracic spine based solely on anatomical landmarks was safe with an accuracy comparable to that of published studies on image guided surgery at the thoracic level

Introduction: To evaluate a three-stage procedure for the correction of symptomatic post-traumatic kyphotic deformity of the thoracic or lumbar spine. Methods: Over an 18-month period, five consecutive cases of post-traumatic kyphosis of the thoracic/lumbar spine were analysed. Indications for surgical correction were incapacitating back pain, progression of kyphotic deformity, persistent neurologic deficit and development of late spinal stenosis. All patients underwent a three-staged procedure using two surgeons. At first they were positioned prone for a posterior midline approach, with pedicle screw placement (USS), decompressive laminectomies and facetectomies. For the second stage, the patients were positioned either on left side (for upper thoracic spine) or on the right side (for the thora-columbar junction and lumbar spine). An open, minimal invasive access procedure using the SynFrame retractor was performed. The anterior column was reconstructed using expandable cages (Synex cages) with autologous bone for interbody fusion. Finally, the patient was again positioned prone for posterior compression, instrumentation and fusion. Results: The five patients comprised four males and one female. Age range was 26–51 years. Level of injury was T7–L3. Time since injury was two to10 years. Mean operating time was eight hours. One patient required a thoracic pedicle screw revision and another a posterior deep wound infection requiring wound debridement and lavage. Follow-up period was three to 15 months. All patients reported improvement in pain post-operatively. Lower rates of pain improvement correlated with longer standing symptomatic injuries. No worsening of neurological deficit occurred. Conclusion: Early correction of symptomatic kyphosis is recommended and aims to improve pain, deformity and function. Recognition of the correct type of injuries is essential to avoid late deformity. Correction of symptomatic post-traumatic kyphotic deformity is achieved by this three-staged approach. Minimal invasive anterior reconstruction using SynFrame and expandable Synex cages is safe and effective. Two surgeons working in conjunction is advantageous

Introduction: After the introduction of MRI in routine diagnostic work-up, Split cord malformations (SCM) in patients with Congenital spinal deformities (CSD) is more easily diagnosed and probably overtreated. Aim: To evaluate the necessity of neurosurgical management of SCM before corrective spinal surgery. Study Design: Retrospective case series. Patients and Methods: Thirty-two patients aged 11 years + 8 months (4–18 years) with CSDs with a follow up of 51,7+/−26,6 months were analyzed. SCM were classified as Type I(septum dividing the spinal cord and dura into two separate hemicords) and Type II(two hemicords within single dura) according to Pang. Eighteen patients with type I underwent neurosurgical intervention (spur excision and creating a single dural cuff) before corrective surgery (15 sequential and 3 simultaneous). Fourteen patients with type II were treated with posterior instrumentation without dealing with the intraspinal abnormalities. The basic maneuvers were translation, compression and shortening to realign spinal column, avoiding distraction forces and intrusion of any instrument into the spinal canal around anomalous segments. Neurological monitoring was done by the wake-up test. Results: At final follow up, scoliosis improved from 65,7+/−22 to 37+/−15 degrees (45%) in type I and from 74,3+/−21,8 to 39,4+/−18,7 degrees (47%) in type II. The correction loss was 2,3 degrees in patients with type I SCM and 2,9 degrees in patients with type II SCM. One patient with type I SCM had paraparesis resulting from a misplaced upper thoracic pedicle screws with total recovery after revision. Another patient with type I SCM who had simultaneous surgeries had deterioration of her preoperative neurological deficit only to recover partially. Two patients with type I SCM and one patient with type II SCM developed deep wound infections and needed multiple debridements. Two patients with type I SCM had dural leakage that needed repair. Conclusion: Although it is a common practice to operate all SCMs before corrective surgery in CSD, it may not be necessary in type II which can be managed safely without any neurosurgical intervention

A prospective cohort outcome evaluation of unstable thoracic spine fractures treated with posterior pedicle screw fixation. The purpose of this study was to determine the accuracy of placement and safety of pedicle screws in open reduction of unstable thoracic spine fractures. The surgeries were performed by one of five fellowship trained spinal surgeons. CT scans were formed on twenty-three patients totaling two hundred screws using 3mm cuts. Three independent reviewers assessed and categorized the screw position as within the pedicle or as a violation of the pedicle wall. 98% of the screws were accurate and we recommend the use of pedicle screws in thoracic fractures . A prospective cohort outcome evaluation of unstable thoracic spine fractures treated with posterior pedicle screw fixation. This study is to determine the accuracy of placement, safety of pedicle screws in open reduction of unstable thoracic spine fracture. Surgery was performed by one of five fellowship trained spine surgeons. CT scans were performed on twenty-three patients using 3mm cuts in both sagittal and transverse planes. Pedicle screw position was assessed by three independent reviewers. Screw position was categorized as within the wall of the pedicle or in violation of the wall. Further sub-classification of pedicle wall violation reviewed the direction and distance of perforation. Independent perioperative and postoperative surveillance for complications was done. Twenty-three unstable thoracic spine fractures treated with two hundred posterior pedicle screws were analyzed. The pedicle screws spanned from T1-T12 with the majority of screws in the mid-thoracic region. Of the two hundred thoracic pedicle screws placed, 70% were fully contained within the pedicle wall. The remaining screws were deemed “out” with cortical perforation (30%). Of these, 20% were lateral perforations, 5% were medial perforations and 5% were anterolateral perforations. No superior, inferior, or anteromedial perforations were found. There was no regional area variation in incidence of perforations. 10% of all perforations were directly related to pedicle diameter to screw diameter mismatch. There were no adverse neurological, vascular, or visceral injuries detected intraoperatively or postoperatively. Surgical management of unstable thoracic spine fractures with posterior pedicle screw fixation is safe. 98% of screws had satisfactory accuracy. Although very minor misplacement of pedicle screws occurred, there were no complications and we recommend the use of pedicle screws in thoracic fractures

Objective. The use of all pedicle screw constructs for the management of spinal deformities has gained widespread popularity. However, the placement of pedicle screws in the deformed spine poses unique challenges for the spinal surgeon. The purpose of this study was to evaluate the complications and radiological outcomes of surgery in 124 consecutive patients with spinal deformity. These patients underwent correction of coronal and sagittal imbalance with segmental pedicle screw fixation only. Background. All pedicle screw constructs have been associated with improved correction in all three planes. In patients with severe deformity, such constructs can obviate the need for anterior surgeries, and the higher implant cost is offset by the avoidance of dual anterior and posterior approaches. Pedicle screw fixation enables enhanced correction of spinal deformities, but the technique is still not widely applied for thoracic deformities for fear of neurological complications. This is a retrospective study that was carried out on 124 patients who underwent segmental screw fixation for coronal and sagittal spinal deformities. The purpose of this study was to evaluate the complications and outcomes of this technique and also assess the evidence of enhanced correction. Material and Methods. A total of 124 consecutive patients subjected to pedicle screw fixation for spinal deformities were analysed after a minimum period of follow-up of two years. Etiologic diagnoses were idiopathic scoliosis in 32, neuromuscular scoliosis 48, Scheuermann's kyphosis in 28 and others 16. They were reviewed using the medical records and preoperative, intraoperative and postoperative radiographs. Computed tomography was performed when screw position was questionable. Deformity correction was determined on preoperative and postoperative radiographs. The positions of the screws were evaluated using intraoperative and postoperative radiographs. There were 51 male and 73 female patients with the mean age of 17.2 years (range, 10-25 years). The average cobb angle for scoliosis and kyphosis were 55°(range 45°-85°) and 72° (range 68°-100°) respectively. Results. A total of 2784 pedicle screws were inserted and 1488 screws were inserted in the thoracic spine (18 screws/patient). Screw-related neurological complications occurred in two patients 0.4%; these comprised a transient paraparesis and dural tear. Other complications comprised six intraoperative pedicle fractures, 12 screw loosening, four postoperative infections and one haemothorax. There were no significant screw-related neurological or visceral complications. The average correction was 78% for scoliosis and 51% for kyphosis. The mean estimated blood loss was 653 ml (range, 510-850), the mean operation time was 148 minutes (range, 120-220). Conclusion. We were able to demonstrate that application of pedicle screw construct is safe and advantageous in the management of spinal deformities. Significant correction has been achieved with a single stage posterior surgery in all groups. Scoliosis and kyphotic deformity corrections were 78% and 51% respectively; this is far superior to correction achieved with one stage surgery with other constructs. This study showed that improved derotation has decreased the need for thoracoplasty, thus eliminating its risk of associated morbidity. Superior control of the deformity obviated the need for an anterior approach in severe curves. Improved correction, lower morbidity and shorter hospitalisation has compensated for higher implant cost. We believe using all pedicle screw fixation is a relatively safe procedure and offers an excellent correction. This correction was maintained throughout the follow up period. Despite our safety record in thoracic pedicle screw placement, we believe this technique can be potentially dangerous in inexperienced hands, and requires a long learning curve. Therefore, a thorough anatomical knowledge of pedicle morphology, a detailed analysis of pre-operative imaging coupled with experience is essential to avoid complications. Ethics approval None. Interest Statement None

Introduction: Some authors (Suk, Barr, Hamill ...) showed that lumbar and thoracic pedicle screws provided adequate reduction of scoliosis. Quality of reduction depends on primary stability of the vertebral anchors. If the anchor has a good primary stability, reduction forces are entirely transferred to the vertebra, which results in reduction of the deformity, whereas, if the anchor has a poor primary stability, it will move when subjected to reduction forces, and this will result in inadequate reduction. Lumbar screws which are advocated by many authors, are extensively used. Thoracic screws are only used by a limited number of surgeons, as most surgeons favour hooks. Polyaxiality facilitates rod positioning; it eliminates the orthogonal stresses that are generated during tightening and which are known to be responsible for screw fracture. The drawback manoeuvre consists in applying forces directly to the vertebra via the anchor; the deformity is reduced by gently translating the vertebra towards the rod. The polyaxial vertebral claw that we are presenting here is a self-stabilising implant that provides the same primary stability as the screw and allows application of multidirectional drawback forces. Materials and methods: The system consists of self-stabilising vertebral anchors, either screws or claws. Each anchor is polyaxial and features a threaded extension that allows translation of the vertebra towards the rod. Connection of the screw or claw to the rod is provided by connecting clamps. The first operative step consists of inserting the vertebral anchors, favouring the apex of the deformity. The insertion technique is described in detail. The claw is locked independently, prior to securing the rod on to the claw. The second operative step consists of positioning the rods which are bent to the ideal sagittal curve. Polyaxiality and threaded extensions make rod positioning an easy step. Progressive tightening of the nuts results in correction of the deformity as it slowly moves the vertebrae towards the rods. The translation force is distributed over all the anchors, ensuring a gentle reduction manoeuvre with no risk of back out of the implants. Approaching vertebrae at the end of the reduction manoeuvre results in vertebral derotation. It is not necessary to use distraction which is considered hazardous. Results: 35 such instrumentations have been used in patients with idiopathic scoliosis over the previous 12 months. We have used an average of nine screws and four claws per patient, mainly thoracic pedicle/transverse claws. Main curve correction was 71% (average curve was 59° preoperatively and 17° postoperatively). Average correction of the uninstrumented lumbar curve was 73%. The upper curve improved from 34° to 15°. The slope of the first uninstrumented vertebra was 14° pre-operatively and 6° postoperatively. In the sagittal plane, the average angle of thoracic kyphosis in hollow backs (kyphosis less than 15°) was 9°, increasing up to 27° postoperatively. Discussion: This instrumentation is characterised by stable implants which provide a quality of reduction similar to that achieved with pedicle screws. Vertebral claws are easy to insert and have a better primary stability than screws. Poly-axiality is a common feature to all the implants of this system; it greatly facilitates placement of the implants and allows to apply traction simultaneously to all the anchors, which results in progressive, gentle reduction. Simultaneous traction application ensures adequate correction of the thoracic kyphosis (gain of 18°). As a matter of fact, severe kyphosis can be bent into the rods, and translation of the vertebrae towards the rods is very easy. Adequate reduction of the main curve results in correction of the underlying lumbar curve and shifting of the first uninstrumented vertebra into a more horizontal position. Conclusion: This instrumentation based on stable poly-axial implants, should allow to improve the quality of reduction of scoliosis