Learning curve across 2000 thoracolumbar pedicle screw placements using O-arm navigation: technical difficulties and their solutions.

INTRODUCTION: Instrumentation using the intraoperative O-arm navigation technique appears safer than its predecessor techniques. However, only a handful of surgeons often used navigation during spinal surgeries. Too many operative glitches and unreliable navigation accuracy were the important reasons cited even by experienced surgeons for not using spinal navigation. We have studied the accuracy of pedicle screw placement during the learning curve and beyond it. We have also discussed in detail the intricacies of the technique and solutions to the difficulties encountered using spinal navigation. MATERIALS AND METHODS: A total of 2000 thoracolumbar pedicle screws have been placed in the 324 spine surgeries meeting the inclusion and exclusion criteria included in this retrospective study. We have divided 2000 pedicle screw placements into consecutive groups of 200 each. We have compared these groups for the accuracy of screw placement with the surgeon's experience. RESULTS: The accuracy of pedicle screw placement using the "in-versus-out" grading system in group 1 was 85.5% which significantly increased in group 2 to 93.5% (p-value: 0.0099), and thereafter, there was a nonsignificant increase in subsequent groups with the graph achieving the shape of a plateau. CONCLUSION: Surgeons should learn the correct principles of the technique of O-arm navigation to prevent the loss of accuracy and place pedicle screws with high accuracy. There is a learning curve of around 30-35 surgeries or 200 pedicle screw placements to acclimatize with the technique of O-arm navigation and learn its principles.

Standalone cage versus anchored cage for anterior cervical discectomy and fusion: a comparative analysis of clinical and radiological outcomes.

PURPOSE: The use of standalone cages (SAC) and anchored cages (AC) in anterior cervical discectomy and fusion surgery (ACDF) has shown advantage of reduced operative time and lower incidence of dysphagia. However, there is limited literature available comparing the clinical and radiological outcomes of SAC and AC. METHODS: We conducted a prospective study for patients undergoing ACDF for cervical radiculopathy or myelopathy. Patient were classified based on the cage used into SAC group and the AC group. Clinical outcomes were assessed using the modified Japanese Orthopedic Association (mJOA) for myelopathy and Neck Disability Index (NDI) and Visual Analogue Scale (VAS) for radiculopathy. Dysphagia was graded as per Bazaz score. Radiologically, global cervical lordosis, segmental lordosis, cage subsidence, and migration were assessed. RESULTS: We analyzed 31 patients in each group with a minimum two year follow-up. The mean VAS improved from 7.9 to 4.56, mean NDI score improved from 27.6 to 19.8, and mean mJOA improved from 10.8 to 11.7 which were statistically significant (p < 0.05); however, no significant difference was noted between the SAC and AC groups. Mean global lordosis improved from 14.4 to 20.3° and mean segmental lordosis improved from 6 to 10.1° at six months and plateaued to 6.9° at final follow up without any significant difference between the groups. The subsidence was statistically more in 12.9% (4/31) in SAC than 6.4% (2/31) in AC. CONCLUSION: AC showed of lower rates of subsidence while both SAC and AC had comparable clinical outcomes and radiological alignment outcomes.

Aneurysmal bone cyst of C2 treated with novel anterior reconstruction and stabilization.

PURPOSE: Aneurysmal bone cysts (ABC) form 1 % of primary bone tumors. Reported incidence rates are no more than 1.4 to 1,00,000. ABC of spine frequently involves posterior elements and commonly affects the lumbar spine (45 %). We present a case of C2 ABC for the challenges it poses due to the rarity of the lesion, tedious to access location, dilemmas relating to the suitable approach for tumor resection and technically demanding stabilization and reconstruction strategy post resection. METHODS: Clinical data analysis was performed to discuss a method of novel anterior column reconstruction following resection of a C2 aneurysmal bone cyst in a 8 year old child with anterior and posterior elements being involved. RESULTS: An 8-year-old girl with an aneurysmal bone cyst of the C2 vertebra underwent staged surgery following pre-operative embolisation. First a posterior approach tumor excision with posterior instrumented fusion was performed. Following which, using a modified anterior retropharyngeal approach anterior tumor excision and fibular graft reconstruction between the C1 lateral mass and C2 body was performed. Complete tumor clearance and stable reconstruction was successfully achieved in our patient. Patient showed excellent clinical outcome with radiological fusion. CONCLUSIONS: Preoperative embolisation in the treatment of ABC has supplemental advantage by reducing blood loss. Modified anterior retropharyngeal approach allows satisfactory clearance for C1-2 lesion and fibular strut graft between the C1 lateral mass and C2 body can provide a stable graft placement with good chance of fusion. Instability and spinal deformity, whether preexisting or post-excision, should be corrected with reconstruction and stabilization to offer best chance of cure in such cases.

Accuracy of pedicle screw insertion by AIRO® intraoperative CT in complex spinal deformity assessed by a new classification based on technical complexity of screw insertion.

PURPOSE: To develop a classification based on the technical complexity encountered during pedicle screw insertion and to evaluate the performance of AIRO® CT navigation system based on this classification, in the clinical scenario of complex spinal deformity. MATERIALS AND METHODS: 31 complex spinal deformity correction surgeries were prospectively analyzed for performance of AIRO® mobile CT-based navigation system. Pedicles were classified according to complexity of insertion into five types. Analysis was performed to estimate the accuracy of screw placement and time for screw insertion. Breach greater than 2 mm was considered for analysis. RESULTS: 452 pedicle screws were inserted (T1-T6: 116; T7-T12: 171; L1-S1: 165). The average Cobb angle was 68.3° (range 60°-104°). We had 242 grade 2 pedicles, 133 grade 3, and 77 grade 4, and 44 pedicles were unfit for pedicle screw insertion. We noted 27 pedicle screw breach (medial: 10; lateral: 16; anterior: 1). Among lateral breach (n = 16), ten screws were planned for in-out-in pedicle screw insertion. Among lateral breach (n = 16), ten screws were planned for in-out-in pedicle screw insertion. Average screw insertion time was 1.76 ± 0.89 min. After accounting for planned breach, the effective breach rate was 3.8% resulting in 96.2% accuracy for pedicle screw placement. CONCLUSION: This classification helps compare the accuracy of screw insertion in range of conditions by considering the complexity of screw insertion. Considering the clinical scenario of complex pedicle anatomy in spinal deformity AIRO® navigation showed an excellent accuracy rate of 96.2%.

Delayed chance fracture pattern injury in a case of skeletal fluorosis.

PURPOSE: To document a rare complication of a delayed 'chance fracture pattern'-type injury through the proximal end of a pedicle screw construct in the clinical scenario of skeletal fluorosis. METHODS: A 72-year-old man with fluorosis presented following a fall which resulted in a T12-L1 fracture. Investigations revealed an unstable three-column injury, so the patient was treated with surgical stabilisation using pedicle screw fixation from T11 to L2. He presented 1 month following surgery with worsening back pain. Investigations revealed a fracture through T11 in a 'chance fracture pattern' along the pedicle screw tracts at the proximal end of the construct. An extension of fixation was performed proximally to T8 and he made an uneventful recovery showing fusion at 20-month follow-up. RESULTS: Complication of delayed pedicle fractures, in a 'chance fracture pattern' at the ends of a pedicle screw fixation constructs are a rarely reported in the literature. The occurrence of such a complication in a hyperostotic spine associated with fluorosis makes this a unique clinical scenario which is previously unreported to the best of our knowledge. CONCLUSIONS: This report highlights a very rare complication of chance fracture pattern injury in the clinical scenario of fluorosis. A hyperostotic stiff spine, poor quality of bone and extension of pedicle screw tracts to anterior cortex during primary surgery may have resulted in the occurrence of this rare complication.

Clinical and radiological factors related to the presence of motor deficit in lumbar disc prolapse: a prospective analysis of 70 consecutive cases with neurological deficit.

PURPOSE: To analyse the clinic-radiological factors associated with neurological deficit following lumbar disc herniation. METHODS: A prospective, cross-sectional study was performed in 140 cases of micro-discectomy following lumbar disc herniation. Group 1 included 70 consecutive patients with motor deficit and group 2 (controls) included 70 patients with intact neurology. Motor deficit was defined as the occurrence of motor power ≤3/5 in L2-S1 myotomes. Multiple clinical and radiological parameters were studied between the two groups. RESULTS: Patients with diabetes (p 0.004), acute onset of symptoms (p 0.036), L3-4 discs (p 0.001), sequestrated discs (p 0.004), superiorly migrated discs (p 0.012) and central discs (p 0.004), greater antero-posterior disc dimension (p 0.023), primary canal stenosis (p 0.0001); and greater canal compromise (p 0.002) had a significant correlation with the development of neurological deficit. The presence of four or more of these risk factors showed a higher chance of the presence of motor deficit (sensitivity of 74%, specificity of 77%). Age, sex, previous precipitating events, severity of pain, smoking, and number of herniations levels did not affect the occurrence of deficit (p > 0.05 for all). Patients with or without bladder symptoms were similar with respect to all clinico-radiological parameters. However, the time delay since the occurrence of deficit was significantly shorter in patients with bladder involvement (p 0.001). CONCLUSION: Patients with diabetes, acute presentation, central, sequestrated and superiorly migrated discs, high lumbar disc prolapse, and greater spinal canal compromise are predisposed to the presence of motor deficit.

ISSLS PRIZE IN CLINICAL SCIENCE 2017: Is infection the possible initiator of disc disease? An insight from proteomic analysis.

STUDY DESIGN: Proteomic and 16S rDNA analysis of disc tissues obtained in vivo. OBJECTIVE: To address the controversy of infection as an aetiology for disc disorders through protein profiling. There is raging controversy over the presence of bacteria in human lumbar discs in vivo, and if they represent contamination or infection. Proteomics can provide valuable insight by identifying proteins signifying bacterial presence and, also host defence response proteins (HDRPs), which will confirm infection. METHODS: 22 discs (15-disc herniations (DH), 5-degenerate (DD), 2-normal in MRI (NM) were harvested intraoperatively and immediately snap frozen. Samples were pooled into three groups and proteins extracted were analysed with liquid chromatography-tandem mass spectrometry (LC-MS/MS). Post identification, data analysis was performed using Uniprotdb, Pantherdb, Proteome discoverer and STRING network. Authentication for bacterial presence was performed by PCR amplification of 16S rDNA. RESULTS: LC-MS/MS analysis using Orbitrap showed 1103 proteins in DH group, compared to 394 in NM and 564 in DD. 73 bacterial specific proteins were identified (56 specific for Propionibacterium acnes; 17 for Staphylococcus epidermidis). In addition, 67 infection-specific HDRPs, unique or upregulated, such as Defensin, Lysozyme, Dermcidin, Cathepsin-G, Prolactin-Induced Protein, and Phospholipase-A2, were identified confirming presence of infection. Species-specific primers for P. acnes exhibited amplicons at 946 bp (16S rDNA) and 515 bp (Lipase) confirming presence of P. acnes in both NM discs, 11 of 15 DH discs, and all five DD discs. Bioinformatic search for protein-protein interactions (STRING) documented 169 proteins with close interactions (protein clustering co-efficient 0.7) between host response and degenerative proteins implying that infection may initiate degradation through Ubiquitin C. CONCLUSION: Our study demonstrates bacterial specific proteins and host defence proteins to infection which strengthen the hypothesis of infection as a possible initiator of disc disease. These results can lead to a paradigm shift in our understanding and management of disc disorders.

Spinal cord herniation following cervical meningioma excision: a rare clinical entity and review of literature.

BACKGROUND: Spinal cord herniation following surgery is an extremely uncommon clinical condition with very few reports in published literature. This condition usually occurs as a spontaneous idiopathic phenomenon often in the thoracic spine or following a scenario of post traumatic spinal cord/nerve root injury. Rarely has it been reported following spinal cord tumor surgery. PURPOSE: To document a case of cervical spinal cord herniation as a late onset complication following spinal cord tumor surgery with an atypical presentation of monoparesis. DESIGN: Case report. METHODS: We describe the clinical presentation, operative procedure, post operative outcome and review of literature of this rare clinical condition. RESULTS: A 57-year-old man presented with right upper limb monoparesis due to a spinal cord herniation 6 years after a cervical intradural meningioma excision. The patients underwent surgery to reduce the herniation and duroplasty with subsequent complete resolution of symptoms. CONCLUSIONS: Spinal cord herniation must be considered as differential diagnosis in scenarios of spinal cord tumor excision presenting with late onset neurological deficit. These cases may present as paraparesis, Brown-sequard syndrome and rarely as in our case as monoparesis.

Effectiveness of Riluzole as a pharmacotherapeutic treatment option for early cervical myelopathy: a double-blinded, placebo-controlled randomised controlled trial.

PURPOSE: To evaluate the effectiveness of Riluzole as a pharmacotherapeutic treatment option for early cervical myelopathy using clinical parameters and DTI analysis. METHODS: Early cervical myelopathy cases with MJOA scores ≥13, were recruited for the double-blinded, placebo-controlled randomised control trial. Thirty cases with fifteen cases each in the test and placebo group were studied. Analysis was done using diffusion tensor imaging (DTI) and clinical evaluation, pre- and post-institution of sodium channel blocker Riluzole for a period of 1 month (50 mg twice daily). Placebo group was treated with Vitamin B complex tablets. Diffusion co-efficient fractional anisotrophy (FA), apparent diffusion co-efficient (ADC), volume ratio (VR), relative anisotrophy (RA) and Eigen vectors were calculated. Outcomes analysis was based on clinical scores of MJOA, Nurick grading, SF-12, NDI, and statistical analysis of DTI datametrics. RESULTS: The mean MJOA score was 15.6 (13-17) with no significant change in the test and control groups. The mean ADC, FA values were 1533.36 (1238-1779) and 494.36 (364-628) and changed to 1531.57 (1312-2091) and 484.86 (294-597), respectively, in the Riluzole group. However, the changes in the values of ADC, FA, and other co-efficients including VR, RA and eigenvectors in the two groups were not statistically significant. The functional scores in the SF-12 and NDI questionnaires did not change significantly. CONCLUSIONS: Our study did not show a significant change in the clinical outcome and DTI Indices with the use of Riluzole as a standalone pharmacotherapeutic agent for early cervical myelopathy. More studies may be needed to confirm the usefulness of Riluzole as a treatment option for cervical myelopathy.

Incidence and preventability of adverse events in an orthopaedic unit: a prospective analysis of four thousand, nine hundred and six admissions.

PURPOSE: We aimed to identify the incidence and preventability rate of adverse events (AEs) occurring in a specialty orthopaedic unit. METHODS: Four thousand nine hundred and six consecutive in-patient admissions over six months in an orthopaedic unit were prospectively analysed. The total indoor patient capacity was segregated into 25-bed units each, and AEs were recorded on a daily basis by two observers. Each event was assessed by allotting a causation score (1-6), with a score of ≥ 4 implying a systemic/individual failure of healthcare provision. A preventability score (1-6) was allotted and scores ≥ 4 were considered to be preventable. RESULTS: Four hundred and sixty-seven patients (9.5 %) suffered a total of 529 AEs, including 127 readmissions; 49 patients suffering multiple events. Three hundred and thirty-three (62.9 %) events had a causation score of ≥ 4, indicating a failure of healthcare delivery systems. Three hundred and one (56.8 %) events could have been prevented with better regulation and adherence to management protocols. Hospital-acquired infections were the most common event, with surgical-site infection in 102 cases (19.2 and 2 % overall) and catheter-associated urinary tract infections noted in 45 (8.5 %) patients. Medical events included seven deep vein thrombosis, two pulmonary embolisms, five myocardial infarctions and one stroke. AEs occurred 56.3 % in the ward, 4.3 % in the intensive care unit (ICU), 6.2 % in the emergency room, and 9.0 % in the operating theatre. CONCLUSION: This prospective study documented an adverse event rate of 9.5 %, of which 56 % were preventable. AEs occurred in all stages of treatment care, emphasising the need for vigilance during the entire treatment process.

Pyogenic lumbar spondylodiscitis treated with transforaminal lumbar interbody fusion: safety and outcomes.

PURPOSE: Our aim was to study the safety and outcomes of posterior instrumentation and transforaminal lumbar interbody fusion (TLIF) for treating pyogenic lumbar spondylodiscitis. METHODS: Retrospective analysis was performed on prospectively collected data of 27 consecutive cases of lumbar pyogenic spondylodiscitis treated with posterior instrumentation and TLIF between January 2009 and December 2012. Cases were analysed for safety, radiological and clinical outcomes of transforaminal interbody fusion using bone graft ± titanium cages. Interbody metallic cages with bone graft were used in 17 cases and ten cases used only bone graft. Indications for surgical treatment were failed conservative management in 17, neurodeficit in six and significant bony destruction in four. RESULTS: There were no cases reporting cage migration, loosening, pseudoarthrosis or recurrence of infection at a mean follow-up of 30 months. Clinical outcomes were assessed using Kirkaldy-Willis criteria, which showed 14 excellent, nine good, three fair and one poor result. Mean focal deformity improved with the use of bone graft ± interbody cages, and the deformity correction was maintained at final follow-up. Mean pre-operative focal lordosis for the graft group was 8.5° (2-16.5°), which improved to 10.9 °(3.3-16°); mean pre-operative focal lordosis in the group treated with cages was 6.7 °(0-15°), which improved to 7°(0-15°) . CONCLUSION: TLIFs with cages in patients with pyogenic lumbar spondylodiscitis allows for acceptable clearance of infection, satisfactory deformity correction with low incidence of cage migration, loosening and infection recurrence.

Prediction of posterior ligamentous complex injury in thoracolumbar fractures using non-MRI imaging techniques.

PURPOSE: We aimed to formulate a radiological index based on plain radiographs and computer tomography (CT) to reliably detect posterior ligamentous complex (PLC) injury without need for MRI. METHODS: Sixty out of 148 consecutive thoracolumbar fractures with doubtful PLC were assessed with MRI, CT and radiographs. PLC injury was assessed with the following radiological parameters: superior-inferior end plate angle (SIEA), vertebral body height (BH), local kyphosis (LK), inter-spinous distance (ISD) and inter-pedicular distance (IPD) and correlated with MRI findings of PLC injury. Statistical analysis was performed to identify the predictive values for the parameters to identify PLC damage. RESULTS: MRI identified PLC injury in 25/60 cases. The ISD and LK were found to be significant predictors of PLC injury. On radiographs the mean LK with PLC damage was 25.86° compared to 21.02° with an intact PLC (p = 0.006). The ISD difference was 6.70 mm in cases with PLC damage compared to 2.86 mm with an intact PLC (p = 0.011). In CT images, the mean LK with PLC damage was 22.96° compared to 18.44° with an intact PLC ( p = 0.019). The ISD difference was 3.10 mm with PLC damage compared to 1.62 mm without PLC damage (p = 0.005). CONCLUSIONS: On plain radiographs the presence of LK greater than 20 °(CI 64-95) and ISD difference greater than 2 mm (CI 70-97) can predict PLC injury. These guidelines may be utilised in the emergency room especially when the associated cost, availability and time delay in performing MRI are a concern.

Condylus tertius with atlanto-axial rotatory fixation: an unreported association.

The "condylus tertius" or the "third occipital condyle" is an embryological remnant of the proatlas sclerotome. Anatomically, it is attached to the basion and often articulates with the anterior arch of the atlas and the odontoid apex; hence, it is also called the "median occipital condyle". It is a rare anomaly of the cranio-vertebral junction (CVJ) that can lead to instability and compression of important surrounding neurovascular structures. We report a case of a 16-year-old boy who presented with suboccipital neck pain, torticollis and right sided hemiparesis. Plain radiographs revealed an increased atlanto-dental interspace (ADI) with a retroflexed odontoid. Open mouth view showed asymmetry of the articular processes of the atlas with respect to the dens. Computed tomography (CT) of the CVJ delineated the third occipital condyle. Furthermore, on dynamic CT study, a type 3 atlanto-axial rotatory fixation (AARF) was clearly demonstrated. Magnetic resonance imaging (MRI) of the CVJ revealed severe right-sided spinal cord compression by the retroflexed and rightward deviated dens. It also revealed disruption of the left alar and transverse ligaments. The patient was treated with 8 weeks of cranial traction and reasonable alignment was obtained. This was followed by C1-C2 lateral mass screw fixation and C1-C2 interlaminar wiring to maintain the alignment. A review of the literature did not reveal any cases of condylus tertius associated with non-traumatic AARF. An accurate knowledge of the embryology and imaging features of this rare CVJ anomaly is useful in the prompt diagnosis and management of such patients.

Utility of Asymmetric Multilevel Pontes Osteotomy in Ankylosing Spondylitis with Scoliosis using Ultrasonic Bone Scalpel: Case Report.

Introduction: Ankylosing spondylitis is a spondyloarthropathy that commonly involves the axial skeleton with predilection to the sacro-iliac joints and spine. The disease frequently results in a smooth globular kyphotic deformity of the spine; however, a coronal plane scoliotic deformity is extremely rare. We present a unique case of scoliotic deformity in a patient diagnosed with ankylosing spondylitis. To the best of our knowledge, following a review of the literature, this appears to be the first report of this kind. Case Report: A 23-year-old male patient presented with chronic back pain, stiffness, and a truncal shift of the body. He had a rigid left-sided thoracolumbar curve measuring 41° with a coronal imbalance of 3.6 cm. We present a case report on scoliosis deformity correction performed with a four-level asymmetric pontes osteotomy using a bone scalpel with excellent correction of the scoliotic deformity that was well maintained at 2-year follow-up. Conclusion: Scoliosis in ankylosing spondylitis has not been documented in literature. We report the complete correction of the deformity, which is well maintained at the 2-year follow-up.

What does a department need to get involved in clinical trials?

Clinical trials are conducted to evaluate the usefulness of a drug, medical treatment, surgical intervention, radiological procedure, behavioral intervention, or preventive health care strategy. Clinical trials are challenging, time-consuming, and need careful planning and execution. There are certain requirements for an academic unit to be ready for conducting quality research, especially clinical trials. These include logistical concerns, infrastructure, appropriately trained human resources, conformity with ethical compliances and regulatory compliances as per the laws governing the respective geographical regions. Infrastructure requirements include research division space, robust data archival system, archival of imaging data, laboratory services, information technology division and facilities for the appropriate consenting process. Human resources such as principal investigators, data managers, clinical research assistants and biostatisticians are needed to execute the clinical trial as per the study design. Adherence to ethical and regulatory standards; during the conduct of the clinical trial are imperative. Strict compliance with prevailing governing laws in the country is a prerequisite for a department to get involved in clinical trials. The department also needs to put in place an institutional ethics committee; the composition of which is often governed by regulatory laws. The ethical aspects of the trial undergo a formal scrutiny by an Institute ethics committee that ensures quality care to the patient, and safeguards the patient's rights and privileges. The academic unit of any department forms the core for possible research and pursuit of clinical trials. A department with rich clinical experience and expertise in the filed aids in the execution of quality research. The academic department must consider grant writing and multiple center collaborative research projects in due course of time to further enhance the quality of clinical trials and research output.

Cervical Schwannoma camouflaged by cervical intervertebral disc prolapse-A case report.

INTRODUCTION: Cervical prolapsed intervertebral disc is one of the common conditions causing cervical myeloradiculopathy. Anterior Cervical Discectomy and Fusion (ACDF) is the standard line of management for the same. Intradural neurogenic origin tumors are relatively rare and can present with features of myeloradiculopathy. Radiological imaging plays important role in diagnosis of such pathologies. CASE REPORT: We report a patient with C5-6 cervical disc prolapse that presented with radiculopathy symptoms in the right upper limb, which was refractory to conservative care. He underwent a C5-6 ACDF and reported complete relief from symptoms at 4 weeks. He developed deteriorating symptoms over the next 10 weeks and presented at 14 weeks follow-up with severe myeloradiculopathy symptoms on the left upper limb with upper limb weakness. A fresh MRI identified an intradural extramedullary tumor with cystic changes at the index surgery level. This was treated with tumor excision and histopathology confirmed a diagnosis of schwannoma. Simultaneous presence of cord signal changes with disc herniation obscured the cystic schwannoma which became apparent later on contrast enhanced MRI imaging. CONCLUSION: Careful review of preoperative imaging and contrast MRI study may help in diagnosing cystic schwannomas with concomitant cervical disc herniations that have cord signal changes.

"Critical pedicle wall" breaches analysis in complex spinal deformity using O-arm navigation.

Background: Free-hand and fluoroscopic-guided pedicle screw placement has been associated with higher rates of pedicle breaches (frequency range 15-40% especially in deformed pedicles). Neurological complications are more "critical" (i.e., frequent and significant) with medial and inferior pedicle-wall breaches due to the proximity of the neural elements. Here, we analyzed the effectiveness of O-arm navigation in minimizing "critical" pedicle wall breaches and their complications in 21 complex spinal deformity cases. Methods: Twenty-one complex spinal deformity cases were prospectively managed with O-arm-navigated posterior-instrumented fusions. Preoperative assessment included; evaluation of the type of scoliosis, the magnitude of the deformity, and the anatomy of the pedicles - (i.e., classified using Watanabe et al.). The O-arm was used to confirm and grade both the intraoperative and postoperative location of screws. Other variables analyzed included; duration of surgery, estimated blood loss, complications, and radiation exposure. Results: In 21 patients, 259 (63.45%) of 384 pedicles were instrumented; we observed 22 of 259 pedicle screw breaches. Significant (>2 mm) breaches were observed in two medial and one inferior wall cases that required revision; the overall biomechanically significant screw breach rate was (3/259) 1.2% with an accuracy rate of 98.8%. Pedicle screw placement resulted in another 14 nonsignificant (<2 mm) breaches; ten were medial and four involved the inferior wall. As anterior, lateral, and "in-out-in" trajectory pedicle screws beaches were nonsignificant, they were not included in our analysis. Conclusion: O-arm navigation decreased the incidence of medial and inferior (i.e., >2 mm "critical") pedicle screw breaches applied in 21 patients with deformed pedicles due to scoliosis. Further, the O-arm minimized the operating time, decreased the estimated blood loss, and reduced the incidence of complications.

Osteosclerotic Multiple Myeloma without POEMS Syndrome - A Rare Case Report.

Introduction: Multiple myeloma is a plasma cell neoplasm that is commonly associated with lytic bone lesions; however, osteosclerotic multiple myeloma is a rare entity. Osteosclerotic multiple myeloma has been reported in association with POEMS syndrome. Case Presentation: A 60-year-old female patient presented to us with low back pain for 2 months. The investigations revealed that the patient had multiple osteosclerotic lesions in the axial skeleton with a L4 ivory vertebra. The serum immunoelectrophoresis was negative. Positron emission tomography scan was done which showed multiple skeletal lesions in the right iliac bone, left femoral neck, thoracic vertebrae T1, T6, T12, and lumbar vertebra L4. Biopsy and immunohistochemistry of the lesion showed plasma cell proliferation; producing lambda light chains. However, there were no features of POEMS syndrome including polyneuropathy, organomegaly, endocrinopathy, and skin changes. The patient was started on chemoradiation and achieved clinical remission and was asymptomatic at 12 months follow-up. Conclusion: Osteosclerotic myeloma without the features of POEMS syndrome is an extremely rare entity. This case reports documents a unique clinical scenario of osteosclerotic non-secretory light chain myeloma without POEMS syndrome.

Utility of selected sequence MRI imaging of the axial skeleton in the diagnosis of axial spondyloarthritis.

Background: Whole body MRI has been used to evaluate inflammatory lesions associated with axial spondyloarthritis (SpA). These sequences are extensive, time consuming and add to the cost of the investigation. We aimed to determine the utility of selected sequence MRI imaging of the axial skeleton including spine, pelvis and sacroiliac (SI) joints to identify features of (SpA). Methods: A retrospective study was conducted on 76 patients diagnosed with SpA that underwent a selective sequence MRI imaging of the axial skeleton. The MRI were reported by two musculoskeletal trained radiologists were reviewed. The MRI sequences included whole spine sequences of sagittal STIR (short tau inversion recovery), T1 weighted and T2 weighted sequences. Coronal STIR and T1 weighted images were studied for SI joints and pelvis. The MRI were assessed based on the guidelines outlined by the Assessment of SpondyloArthritis International Society (ASAS) for features of spondylitis, spondylodiscitis, enthesitis, synovitis, capsulitis, bone marrow edema, fatty marrow replacement, erosions and bony ankylosis. Inflammatory lesions were documented in the spine, sacroiliac, facet, hip and costovertebral joints. Results: The mean scan duration was 28 min. SI joint involvement was noted in 74 (97.3%) of patients. The other most prevalent findings were spondylitis in 44 (57.8%) patients, costovertebral joint involvement in 31 (40.7%), facet joint lesions in 32 (42.1%), spondylodiscitis in 21 (27.6%), enthesitis in 13 (17.1%), hip lesions in 16 (21%) and ankylosis in 10 (13.1%). Conclusions: This selective sequence imaging of the pelvis and spine was able to identify typical lesions of SpA in a shorter time period. Fifty-five percent patients had lesions in the posterior elements including facet joints and costovertbral joints that would be missed on traditional SI joint imaging.