In multilevel posterior cervical instrumented fusions, extending the fusion across the cervico-thoracic junction at T1 or T2 (CTJ) has been associated with decreased rate of re-operation and pseudarthrosis but with longer surgical time and increased blood loss. The impact on patient reported outcomes (PROs) remains unclear. The primary objective was to determine whether extending the fusion through the CTJ influenced PROs at 3 and 12 months after surgery. Secondary objectives were to compare the number of patients reaching the minimally clinically important difference (MCID) for the PROs and mJOA, operative time duration, intra-operative blood loss (IOBL), length of stay (LOS), discharge disposition, adverse events (AEs), re-operation within 12 months of the surgery, and patient satisfaction.

This is a retrospective analysis of prospectively collected data from a multicenter observational cohort study of patients with degenerative cervical myelopathy. Patients who underwent a posterior instrumented fusion of 4 levels of greater (between C2-T2) between January 2015 and October 2020 with 12 months follow-up were included. PROS (NDI, EQ5D, SF-12 PCS and MCS, NRS arm and neck pain) and mJOA were compared using ANCOVA, adjusted for baseline differences. Patient demographics, comorbidities and surgical details were abstracted. Percentafe of patient reaching MCID for these outcomes was compared using chi-square test. Operative duration, IOBL, AEs, re-operation, discharge disposittion, LOS and satisfaction were compared using chi-square test for categorical variables and independent samples t-tests for continuous variables.

A total of 206 patients were included in this study (105 patients not crossing the CTJ and 101 crossing the CTJ). Patients who underwent a construct extending through the CTJ were more likely to be female and had worse baseline EQ5D and NDI scores (p> 0.05). When adjusted for baseline difference, there was no statistically significant difference between the two groups for the PROs and mJOA at 3 and 12 months. Surgical duration was longer (p 0.05). Satisfaction with the surgery was high in both groups but significantly different at 12 months (80% versus 72%, p= 0.042 for the group not crossing the CTJ and the group crossing the CTJ, respectively). The percentage of patients reaching MCID for the NDI score was 55% in the non-crossing group versus 69% in the group extending through the CTJ (p= 0.06).

Up to 12 months after the surgery, there was no statistically significant differences in PROs between posterior construct extended to or not extended to the upper thoracic spine. The adverse event profile did not differ significantly, but longer surgical time and blood loss were associated with construct extending across the CTJ.

En bloc resection for primary bone tumours and isolated metastasis are complex surgeries associated with a high rate of adverse events (AEs). The primary objective of this study was to explore the relationship between frailty/sarcopenia and major perioperative AEs following en bloc resection for primary bone tumours or isolated metastases of the spine. Secondary objectives were to report the prevalence and distribution of frailty and sarcopenia, and determine the relationship between these factors and length of stay (LOS), unplanned reoperation, and 1-year postoperative mortality in this population.

This is a retrospective study of prospectively collected data from a single quaternary care referral center consisting of patients undergoing an elective en bloc resection for a primary bone tumour or an isolated spinal metastasis between January 1st, 2009 and February 28th, 2020. Frailty was calculated with the modified frailty index (mFI) and spine tumour frailty index (STFI). Sarcopenia, determined by the total psoas area (TPA) vertebral body (VB) ratio (TPA/VB), was measured at L3 and L4. Regression analysis produced ORs, IRRs, and HRs that quantified the association between frailty/sarcopenia and major perioperative AEs, LOS, unplanned reoperation and 1-year postoperative mortality.

One hundred twelve patients met the inclusion criteria. Using the mFI, five patients (5%) were frail (mFI ³ 0.21), while the STFI identified 21 patients (19%) as frail (STFI ³ 2). The mean CT ratios were 1.45 (SD 0.05) and 1.81 (SD 0.06) at L3 and L4 respectively. Unadjusted analysis demonstrated that sarcopenia and frailty were not significant predictors of major perioperative AEs, LOS or unplanned reoperation. Sarcopenia defined by the CT L3 TPA/VB and CT L4 TPA/VB ratios significantly predicted 1-year mortality (HR of 0.32 per one unit increase, 95% CI 0.11-0.93, p=0.04 vs. HR of 0.28 per one unit increase, 95% CI 0.11-0.69, p=0.01) following unadjusted analysis. Frailty defined by an STFI score ≥ 2 predicted 1-year postoperative mortality (OR of 2.10, 95% CI 1.02-4.30, p=0.04).

The mFI was not predictive of any clinical outcome in patients undergoing en bloc resection for primary bone tumours or isolated metastases of the spine. Sarcopenia defined by the CT L3 TPA/VB and L4 TPA/VB and frailty assessed with the STFI predicted 1-year postoperative mortality on univariate analysis but not major perioperative AEs, LOS or reoperation. Further investigation with a larger cohort is needed to identify the optimal measure for assessing frailty and sarcopenia in this spine population.

Giant cell tumors of bone (GCTs) are locally aggressive tumors with recurrence potential that represent up to 10% of primary tumors of the bone. GCTs pathogenesis is driven by neoplastic mononuclear stromal cells that overexpress receptor activator of nuclear factor kappa-B/ligand (RANKL). Treatment with specific anti-RANKL antibody (denosumab) was recently introduced, used either as a neo-adjuvant in resectable tumors or as a stand-alone treatment in unresectable tumors. While denosumab has been increasingly used, a percentage of patients do not improve after treatment. Here, we aim to determine molecular and histological patterns that would help predicting GCTs response to denosumab to improve personalized treatment.

Nine pre-treatment biopsies of patients with spinal GCT were collected at 2 centres. In 4 patients denosumab was used as a neo-adjuvant, 3 as a stand-alone and 2 received denosumab as adjuvant treatment. Clinical data was extracted retrospectively. Total mRNA was extracted by using a formalin-fixed paraffin-embedded extraction kit and we determined the transcript profile of 730 immune-oncology related genes by using the Pan Cancer Immune Profiling panel (Nanostring). The gene expression was compared between patients with good and poor response to Denosumab treatment by using the nSolver Analysis Software (Nanostring). Immunohistochemistry was performed in the tissue slides to characterize cell populations and immune response in CGTs.

Two out of 9 patients showed poor clinical response with tumor progression and metastasis. Our analysis using unsupervised hierarchical clustering determined differences in gene expression between poor responders and good responders before denosumab treatment. Poor responding lesions are characterized by increased expression of inflammatory cytokines as IL8, IL1, interferon a and g, among a myriad of cytokines and chemokines (CCL25, IL5, IL26, IL25, IL13, CCL20, IL24, IL22, etc.), while good responders are characterized by elevated expression of platelets (CD31 and PECAM), coagulation (CD74, F13A1), and complement classic pathway (C1QB, C1R, C1QBP, C1S, C2) markers, together with extracellular matrix proteins (COL3A1, FN1,. Interestingly the T-cell response is also different between groups. Poor responding lesions have increased Th1 and Th2 component, but good responders have an increased Th17 component. Interestingly, the checkpoint inhibitor of the immune response PD1 (PDCD1) is increased ~10 fold in poor responders.

This preliminary study using a novel experimental approach revealed differences in the immune response in GCTs associated with clinical response to denosumab. The increased activity of checkpoint inhibitor PD1 in poor responders to denosumab treatment may have implications for therapy, raising the potential to investigate immunotherapy as is currently used in other neoplasms. Further validation using a larger independent cohort will be required but these results could potentially identify the patients who would most benefit from denosumab therapy.

Prolonged length of stay (LOS) is a significant contributor to the variation in surgical health care costs and resource utilization after elective spine surgery. The primary goal of this study was to identify patient, surgical and institutional variables that influence LOS. The secondary objective is to examine variability in institutional practices among participating centers.

This is a retrospective study of a prospectively multicentric followed cohort of patients enrolled in the CSORN between January 2015 and October 2020. A logistic regression model and bootstrapping method was used. A survey was sent to participating centers to assessed institutional level interventions in place to decrease LOS. Centers with LOS shorter than the median were compared to centers with LOS longer than the median.

A total of 3734 patients were included (979 discectomies, 1102 laminectomies, 1653 fusions). The median LOS for discectomy, laminectomy and fusion were respectively 0.0 day (IQR 1.0), 1.0 day (IQR 2.0) and 4.0 days (IQR 2.0). Laminectomy group had the largest variability (SD=4.4, Range 0-133 days). For discectomy, predictors of LOS longer than 0 days were having less leg pain, higher ODI, symptoms duration over 2 years, open procedure, and AE (p< 0.05). Predictors of longer LOS than median of 1 day for laminectomy were increasing age, living alone, higher ODI, open procedures, longer operative time, and AEs (p< 0.05). For posterior instrumented fusion, predictors of longer LOS than median of 4 days were older age, living alone, more comorbidities, less back pain, higher ODI, using narcotics, longer operative time, open procedures, and AEs (p< 0.05). Ten centers (53%) had either ERAS or a standardized protocol aimed at reducing LOS.

In this study stratifying individual patient and institutional level factors across Canada, several independent predictors were identified to enhance the understanding of LOS variability in common elective lumbar spine surgery. The current study provides an updated detailed analysis of the ongoing Canadian efforts in the implementation of multimodal ERAS care pathways. Future studies should explore multivariate analysis in institutional factors and the influence of preoperative patient education on LOS.

Instrumented fusion for lumbar degenerative spondylolisthesis (LDS) has been challenged recently with high impact trials demonstrating similar changes in health-related quality of life (HRQOL) and less morbidity/cost with laminectomy alone. Randomized trials often fail, however, to evaluate a heterogeneous population of patients. A standardized clinical assessment and management plan (SCAMP) was created as a decision aid for surgeons based on the radiographic stability and clinical presentation of patients. The purpose of this study was to compare outcomes of those patients who followed the decision aid with respect to fusion/no fusion to those who did not.

Patients were prospectively enrolled from eleven different Canadian institutions and followed from 2015–2019. A degenerative spondylolisthesis instability classification system (DSIC) was created using best available evidence stratifying patients into three different subtypes (1. stable degenerative spondylolisthesis, 2. potentially unstable spondylolisthesis and 3. unstable spondylolisthesis). The decision aid recommends laminectomy alone for group 1 patients, posterolateral fusion with pedicle screws in type 2 patients and pedicle screw and interbody fusion for type 3 patients. One year changes in HRQOL, length of hospital stay (LOS), medication use and surgical time were compared between each group and in context of whether the treatment fell within the decision aid recommendation. Statistics were performed with STATA software.

There were 394 patients initially enrolled and 334 (84.8%) with full one year data available for comparison. There were 95 type 1 (stable), 224 type 2 (potentially unstable) and 75 type 3 (unstable) patients initially classified. Baseline Ostwestry disability index (ODI), EQ-5D, and SF-12 MCS scores were significantly worse for type 3 patients versus type 1 patients. One hundred and eight patients were treated within the recommendations of the DSIC system (108/334, 32.3%). Surgeons performed interbody fusions in 141 patients (42%) rather than follow DSIC recommending a less invasive approach. There were no significant differences EQ-5D, SF-12 PCS/MCS, PHQ-9 or ODI at one year between patient groups. There was a trend towards shorter operating times for those patients following the DSIC system (195 minutes non-followers versus 180 followers, p=0.078) and reduced hospital stay (4.46 days non-followers versus 3.98 followers, p=0.065).

There were no significant clinical differences in outcome at 1 year whether patients underwent decompression alone, decompression/posterolateral fusion or interbody fusion regardless of the stability classification. Surgeons were more likely to perform potentially unnecessary interbody fusions even in those patients with stable or potentially unstable spondylolisthesis. Although not statistically significant, there is some suggestion that following the DSIC system based on best evidence recommendations leads to more judicious/responsible use of hospital resources. Further study is required to determine why surgeons are more likely to choose more invasive, higher rigidity constructs in patients with LDS.

There is a paucity of published Canadian literature comparing lumbar total disc arthroplasty (LDA) to fusion on patient outcomes in degenerative spondylosis. The purpose of this study is to quantify and compare the long-term patient reported outcomes following LDA and matched-fusion procedures.

We conducted a matched-cohort study comparing consecutive patients enrolled by CSORN who underwent standalone primary LDA or hybrid techniques for degenerative disk disease between 2015–2019. Fusion patients were included by a primary diagnosis of degenerative disk disease, chief complaint of back pain, who received a primary fusion irrespective of technique. Fusion patients were matched by number of involved levels of surgery to LDA counterparts. Outcome scores and patient satisfaction were assessed preoperatively and 2-years postoperatively.

97 patients (39-female, 58-male) underwent LDA or hybrid construct up to 4 levels. 94 patients (52-female, 42-male) underwent a lumbar fusion were selected based on inclusion criteria. 36 LDA and 57 Fusion patients underwent a 1-level surgery. 39 LDA and 25 Fusion patients underwent 2-level surgery. 18 LDA and 7 Fusion patients underwent 3-level surgery. 4 LDA and 5 Fusion patients underwent a 4-level procedure. Slight differences in average cohort age were found (LDA-43.4yrs, Fusion-49.8yrs, p<0.01). Cohort preoperative-BMI (LDA-27.0kg/m², Fusion-27.9kg/m², p=0.29) and total comorbidities (LDA-2.6, Fusion-2.1, p=0.05) demonstrated no clinically significant differences. At 2 year follow-up, no differences were found in ODI improvement (LDA-20.32pts, Fusion-17.02pts, p=0.36), numerical back-pain improvement (LDA-3.5pts, Fusion-3.06pts, p=0.40), numerical leg-pain improvement (LDA-1.67pts, Fusion-1.87pts, p=0.76), and Health Scale improvement (LDA-17.12, Fusion-10.73, p=0.20) between cohorts. Similar positive findings were found in subgroups stratified by number of surgical levels. Satisfaction rate at 2 years was 86.7% and 82.4% for LDA and Fusion patients respectively.

There didn't appear to be significant differences in outcomes or satisfaction through 2 years comparing patients who underwent LDA (whether used in isolation or as part of a hybrid construct) for debilitating degenerative disk disease and isolated spinal fusion for back dominant pain.

The spine is a common site of metastasis. Complications include pathologic fracture, spinal cord compression, and neurological deficits. Vertebroplasty (VP) and Balloon Kyphoplasty (KP) are minimally invasive stabilization procedures used as a palliative treatment to improve mechanical stability, quality of life, and reduce pain. Photodynamic therapy (PDT) is a tumour-ablative modality that may complement mechanical stability afforded by VP/KP. This first-in-human study evaluates PDT safety when applied in conjunction with VP/KP.

This dose escalation trial involved one light only control group and four light-drug doses (50,100,150,200J;n=6) delivered at 150mW from a 690nm diode laser by 800-micron optical fibers prior to KP/VP. Patients eligible for VP/KP in treating pathologic fracture or at-risk lesions at a single level were recruited. Exclusion criteria included spinal canal compromise or neurologic impairment. PDT is a two-step binary therapy of systemic drug followed by intravertebral light activation. Light was applied via bone trochar prior to cementation. This study used a benzoporphyrin derivative monoacid (BPD-MA), Verteporfin (VisudyneTm), as the photosensitizer drug in the therapy. Drug/light safety, neurologic safety, generic (SF-36), and disease-specific outcomes (VAS, EORTC-QLQ-BM22, EORTC-QLQ-C15-PAL) were recorded through six weeks. Phototoxicity and the side effects of the BPD-MA were also examined following PDT use.

Thirty (10 male, 20 female) patients were treated (13 KP, 17 VP). The average age was 61 and significantly different between genders (Male 70yrs vs. Female 57yrs: p 0.05), and tumour status (lytic vs. mixed blastic/lytic: p>0.05). In most cases, fluence rates were similar throughout PDT treatment time, indicating a relatively stable treatment. Twelve (40%) of patients experienced complications during the study, none of which were attributed to PDT therapy. This included two kyphoplasty failures due to progression of disease, one case of shingles, one ankle fracture, one prominent suture, one case of constipation due to a lung lesion, one case of fatigue, and five patients experienced pain that was surgically related or preceded therapy.

Vertebral PDT appears safe from pharmaceutical and neurologic perspectives. KP/VP failure rate is broadly in line with reported values and PDT did not compromise efficacy. The 50J group demonstrated an improved response. Ongoing study determining safe dose range and subsequent efficacy studies are necessary.

Summary Statement

Spinal flexibility in bending and axial torque has been shown to exhibit very modest changes with advancing disc degeneration. This study is the first to address the possible relationship in pure anterior shear and no clear relationship was observed.

The aim of this study is to determine evidence-based guidelines on functional outcomes following common thoracolumbar injuries using a synthesis of systematic literature reviews and consensus expert opinion

A questionnaire was created comprising five cases representative of common thoracolumbar injuries (a thoracic compression fracture, a flexion distraction injury and burst fractures each with varied location, patient demographics and treatment strategies). For each scenario five questions about expected functional outcomes were posed. Questionnaires were distributed to the Spine Trauma Study Group. Responses were combined with available data from a systematic review of the same injuries and outcomes to create consensus evidence based guidelines.

The survey was completed by 31 (57%) of 53 surgeons representing 20 centres across North America. The systematic reviews identified 49 appropriate studies. One year following a L1 burst fracture, a heavy laborer, treated with protective mobilization (cast or brace) has a 40% chance of being pain free, 70% chance of regaining pre-injury range of motion, can expect to be re-employed within 4–6 months and be able to participate in high impact exercise and contact sport with no or minimal limitation. Length of inpatient stay averages 4–5 days. One year following posterior short segment stabilization of a L1 bust fracture in a college football player, there is an expected 45% chance of being pain free and 55% chance of regaining pre-injury ROM. While an ultimate return to high impact exercise and contact sports is anticipated, 32% of experts expect the injury to end a college football career.

Results for the other trauma scenarios are included.

This combination of literature and expert opinion represents the best available evidence on functional prognosis after thoracolumbar trauma. By providing consistent, accurate information surgeons and other care path providers will help patients develop realistic expectations, which may shape and improve their ultimate outcome.

Purpose

Tarsal Tunnel Syndrome (TTS) was first reported by Keck and Lam separately in 1962. It has been regarded as the lower limb equivalent to Carpal Tunnel Syndrome (CTS). The gold standard of diagnosis proposed over the years is nerve conduction study (NCS). In reality, TTS is much harder to diagnose and treat compared to CTS. Signs and symptoms can be mimicked by other foot and ankle conditions. Our unit had not seen a single positive nerve conduction result of TTS in clinically suspicious cases. We have therefore audited our 10 year experience.

Purpose: There is very little evidence to guide treatment of patients with spinal surgical site infection (SSI) who require irrigation and debridement (I& D) with respect to need for single or multiple I& D’s. The purpose of this study is to build a predictive model which stratifies patients with spinal SSI to determine which patients will go on to need single versus multiple I& D.

Method: A consecutive series of 128 patients from a tertiary spine center (collected from 1999–2005) who required I& D for spinal SSI, were studied based on data from a prospectively collected outcomes database. Over 30 variables were identified by extensive literature review as possible risk factors for SSI, and tested as possible predictors of risk for multiple I& D. Logistic regression was conducted to assess each variable’s predictability by a “bootstrap” statistical method. Logistic regression was applied using outcome of I& D – single or multiple as the “response”.

Results: 24/128 patients required multiple I& D. Primary spine diagnosis was approximately represented by ¼ trauma, ¼ deformity, ¼ degenerative and ¼ oncology/inflammatory/other. Six predictors: spine location, medical comorbidities, microbiology of the SSI, presence of distant site infection (ie. UTI or bacteremia), presence of instrumentation and bone graft type, proved to be the most reliable predictors of need for multiple I& D. Internal validation of the predictive model yielded area under the curve (AUC) of .84

Conclusion: Infection factors played an important role in need for multiple I& D. Patients with +MRSA culture or those with distant site infection such as bacteremia with or without UTI or pneumonia, were strong predictors of need for multiple I& D. Presence of instrumentation, location of surgery in the posterior lumbar spine and use of non-autograft bone predicted multiple I& D. Diabetes also proved to be the most significant medical comorbidity for multiple I& D.

Purpose: A systematic review of Health Related Quality of Life Outcomes(HRQOL) in metastatic disease of the spine and content validation of a new Spine Oncology Study Group Outcomes Questionnaire(SOSGOQ). To identify HRQOL questionnaires previously reported for spinal metastases and to validate the content of the new SOSGOQ based on the International Classification of Function and disability(ICF).

Method: A systematic review identified 141 studies. Reported outcome tools were enumerated. The most commonly utilized (ESAS, Karnofsky Scale and ODI) and the SOSGOQ were linked to the ICF. Descriptive statistics examined the frequency and specificity of the ICF linkage. Linkage reliability was evaluated by inter-investigator percentage agreement.

Results: The SOSGOQ contains 56 concepts, with all 4 domains of the ICF represented. 4 concepts could not be linked. There was 100% inter-observer agreement(IOA) for total number of concepts and for those ‘not covered’. 100% of concepts had ‘First and Second’ level linkage. 100% IOA exists at both ‘Component’ and “First Level’ linkage. There was 96.1% IOA at ‘Second’ Level. 33 concepts linked to Third Level with 96.9% IOA. 10 concepts linked at the Fourth Level with 100% IOA.

Conclusion: The SOSGOQ includes all domains relevant for measurement of function and disability and it’s content validity is confirmed by linkage with the ICF. This new questionnaire has superior content capacity to measure disease burden of patients with metastatic disease of the spine than any instruments previously identified in the literature.

Purpose: Multiple studies have described the general injuries associated with mountain biking. However, no detailed assessment of mountain biking associated spinal column fractures and spinal cord injuries (SCI) has previously been reported. The purpose of this study is to describe the patient demographics, injuries, mechanisms, treatments, outcomes and resource requirements associated with spine injuries sustained while mountain biking.

Method: Patients who were injured while mountain biking, and presented to a provincial spine referral centre between 1995 and 2007 inclusive, with SCI and/ or spine fracture were included. A chart review was performed to obtain demographic data, and details of the injury, treatment, outcome and resource requirements.

Results: 102 men and 5 women were identified for inclusion. The mean age at injury was 32.7 years 95%CI[30.6,35.0]. 79 patients (73.8%) sustained cervical injuries, while the remainder sustained thoracic or lumbar injuries. 43 patients (40.2%) sustained a SCI. Of those with cord injuries, 18(41.9%) were ASIA A, 5(11.6%) were ASIA B, 10(23.3%) ASIA C, and 10(23.3%) ASIA D. 67 patients (62.6%) required surgical treatment. The mean length of stay in an acute hospital bed was 16.9 days 95%CI[13.1,30.0]. 33 patients (30.8%) required ICU care, and 31 patients (29.0%) required inpatient rehabilitation. Of the 43 patients (39.6%) who presented with SCI, 14(32.5%) improved by one ASIA category, and 1 (2.0%) improved by two ASIA categories. Two patients remained ventilator-dependent at discharge.

Conclusion: Spine fractures and SCI due to mountain biking accidents typically affect young, male, recreational riders. The medical, personal, and societal costs of these injuries are high. Injury prevention should remain a primary goal, and further research is necessary to explore the utility of educational programs, and the impact of helmets and other protective gear on spine injuries sustained while mountain biking.

Purpose: Screening patients for appropriate treatment is a key component of an effective hospital-based spine service. To date, a standardized and validated method for carrying out this process has not been established. In particular, studies to determine who should staff these screening services, their safety and reliability have not been reported. The goal of this study was to determine the inter-examiner reliability of patient screening assessments by Chiropractors and Spine Physicians.

Method: Prospective observational cohort. 50 consecutive patients with acute lower back pain < 16 weeks duration (QTFSD I, II) referred to a quaternary care hospital spine program were studied. The inter-examiner agreement for 10 physical examination procedures and 5 red flag conditions was calculated using the Cohen’s kappa value. Patients were assessed by one of three spine physicians and one of three Chiropractors for normal or abnormal deep tendon reflexes, nerve root tension signs; lower extremity sensory / motor deficit; muscle atrophy; Schober’s test and depth of lordosis. Any history suggestive of cauda equina, fracture, infection, spinal malignancy or progressive neurological deficit was recorded. The results were compared where applicable, with previously published kappa values for lower back examination procedures.

Results: Four of the 50 patients had one or more red flag conditions with an inter-observer reliability of 0.96; 8 of 10 physical examination procedures had a kappa value of > 0.9; the kappa for + sensory deficit was 0.66 and for + femoral nerve stretch test was 0.47.

Conclusion: In this pilot study, initial patient screening assessments carried out by Chiropractors and Spine Physicians had high inter-observer reliability in 8 of the 10 examination procedures tested and were superior to previously reported multidisciplinary inter-observer kappa values.

Purpose: Clinical practice guideline (CPG) concordant treatment (Ctx) has been shown to be more effective than CPG discordant care (Dtx) in a heterogeneous cohort of patients with acute lower back pain (ALBP). However, patients with underlying spine pathology (e.g. stenosis, disc degeneration, facet joint arthropathy) or without identifiable spine pathology may all present solely with ALBP. At present, it is unknown if underlying spine pathology influences the outcome of Ctx. The purpose of this study was to determine if Ctx is more effective than Dtx in patients with differing underlying spine pathology who present with ALBP.

Method: A Two-arm, randomized control trial with stratified analysis. Inclusion: Ages 19–59; QTFSD I, II ALBP < 4 weeks. Exclusion: “Red Flag” conditions, comorbidities contraindicating Ctx. The primary outcome was the difference between Ctx and Dtx Roland Morris Disability (RDQ) scores at 16 weeks post baseline between study groups. Secondary outcomes: differences in Bodily Pain (BP), Physical Functioning (PF) SF-36 domain scores at 16 weeks. Patients were assessed by a spine physician and randomized to Ctx or Dtx. Patients were stratified on the basis of CT or MRI evidence of:

spinal stenosis;

Hospital / University Ethics approval was obtained.

Results: Eighty-eight patients were recruited; 39 in Ctx & 38 in Dtx group completed the study. Baseline prognostic variables were evenly distributed between groups. Outcomes: mean difference in 16 week RDQ, BP and PF scores between Ctx and Dtx was statistically greatest in group 4 (p< 0.001). There was no significant clinical improvement in RDQ, BP or PF scores in either the Ctx or Dtx in group 2.

Conclusion: Ctx was more effective than Dtx in patients with no identifiable spine pathology and ineffective and equivalent to Dtx in patients with underlying disc degeneration.

Purpose: Prospective Observational Population Study to describe the incidence, demographics and pattern of spinal cord injury in British Columbia, Canada, for 10 years to 2004.

Method: Systematic analysis of prospectively collected spine registry data (Vertebase) at Vancouver General Hospital, B.C., Canada from 1995–2004.

Results: During the 10-year study period the 938 patients were admitted with a traumatic spinal cord injury. The Annual Population-Standardized Incidences ranged from 19.94 to 27.27 per million, with a median incidence of 23.34/million and with no significant change over the study period. The mean age was 39.7 years (34.73 in 1995 and 42.1 in 2004, p< 0.05) with a range of 16–92 years. 79.74 % were males. 48.2% of patients were AISA A on admission, of which 48% were quadraparetic. The most common levels of spinal cord injury were C5 (17.3%), C6 (10%), T1 (9.4%), T12 (5.8%). The Mean ASIA score was 50.22 with a range from 0–100. 19.8% of patients had a GCS£13. The mean ISS was 26.02, range of 0 – 75. Motor vehicle collisions and falls were responsible for 59% and 30% of admissions respectively. Mean length of in-hospital stay was 34 days, ranging from 1 – 275 days. In hospital mortality rate was 2.9%. ASIA Grade, Total Motor Score and anatomical level of injury all correlated directly with Length of stay (p< 0.0001).

Conclusion: Acute Traumatic Spinal Cord Injury remains a major cause of significant morbidity among young males. The incidence appears to be increasing in the elderly. Modern multidisciplinary care has greatly reduced the associated acute mortality. Despite multiple prevention strategies the Annual Population-Standardized Incidence remained unchanged over the study period.

A biomechanical study assessing pedicle screw fixation with three different augmentation methods was performed in human cadaveric vertebrae. Precision opto-electronic measurement of screw motion assessed motion magnitude and patterns, ie translation and/or rotation. Physiological cyclic loads were applied as opposed to the simple pull out test. Augmentation with wires, hook or cement decreased overall motion. There were no significant differences in motion magnitude between the three augmentation methods. Motion patterns for screws with cement augmentation were mainly rotational and differed from the other two methods. Rigid body translations were observed with wires or hook augmentation, suggesting a loosening behaviour. Augmentation with cement resulted in better fixation than wires or hook.

Augmentation of loosened pedicle screws in poor quality bone is often necessary. The purpose of this study was to contrast the kinematics of loosened pedicle screws augmented with laminar hooks, sublaminar wires or calcium phosphate cement.

Cyclic tests of pedicle screws with compressive force and bending moment were carried out on forty-eight screws in twenty-four cadaveric vertebrae (L3-L5) augmented with hooks, wires or cement. Motion at the screw tip and screw head were measured using an optoelectronic camera system and the magnitudes compared in a paired manner using non-parametric statistics. Motion patterns of the screws were determined for each augmentation method.

Augmentation with hook, wire or cement decreased screw motion. There was no significant difference between augmentation methods when the magnitudes of motion, described as ranges and offsets, were compared. Augmentation with cement resulted in mainly rotations of the screws while there were rigid body translations with wires or hooks.

Comparing magnitudes of motion at the screw head and screw tip were insufficient. The screw head and screw tip could be moving in synchronous, indicating rigid body translations. Using simple pull out tests would not detect such differences.

The method used in this study contrasted pedicle screws motion with different augmentations. While there was no detected significant difference in motion magnitude of the pedicle screws, the motion pattern of the screws suggested better augmentation with cement.

Motion of pedicle screws in situ had not been described in the literature. Previous work comparing pedicle screws fixation used the pull out test, while the current method applied physiological loads.

Funding: Funding from the Canadian Institutes for Health Research, Funding from Synthes

Spine Please contact author for diagrams and/or graphs.

The purpose of this study was to investigate the strength profile of the thoracolumbar endplate. Indentation testing was performed on the T9, T12, and L2 endplates of six fresh-frozen human cadaver vertebrae. Indentations were performed in a standardized rectangular grid pattern of seven columns and five rows. There was an incremental increase in the strength of each row moving anterior and posterior from the central row. The relative strength of the anterior regions of the endplate increased with rostral ascent into the thoracic spine.

The purpose of this study was to map the strength profile of the thoracolumbar endplates using indentation testing.

Indentation testing was performed on the T9, T12, and L2 endplates of six fresh-frozen human cadaver spines using a materials testing machine (Dynamight, Instrom Corporation, Canton, MA). A minimum of twenty-five indentations was performed in a rectangular grid (seven columns by five rows). A 3mm hemispherical indendor was lowered at 0.2mm/s to a depth of 3mm producing endplate failure.

The failure load significantly varied with the AP and LAT positions (p< .0001). Each row was significantly stronger than the rows anterior to it (p < 0.04), except for the most row. The most lateral columns were stronger than the central (range: p = .04 – .0002). The mean strength of the L2 posterior row was greater than that for the thoracic endplates (p< .01), while no difference existed between levels within the two anterior rows. The ratio of the mean strength for the posterior row compared to that of the anterior row was significantly different across level (P< 0.036). The ratios for L2, T12, and T9 were 1.35, 0.97, and 0.91 respectively.

The periphery of the thoracolumbar endplate is stronger than the centre. The interaction identified between position and level suggests a relative strength increase in the anterior aspect of the endplate with rostral ascent into the thoracic spine.

This knowledge may assist in preventing intervertebral inplant subsidence by influencing implant positioning and design.

Funding: Canadian Institutes of Health Research Please contact author for figures and/or graphs.

Purpose: The objectives of this study were to determine the effect of posterior instrumentation extension and/or cement augmentation on immediate stabilization of the instrumented level and biomechanical changes adjacent to the spinal instrumentation.

Methods: This study was designed for repeated measures comparison, using 12 T9-L3 human cadaveric segments, to test the effects of posterior rod extension and cement augmentation following T11 corpectomy. The spine was stabilized with a vertebral body replacement device and with posterior instrumentation from T10 to T12. The T12 pedicle tracts were over-drilled to simulate loosened screws in an osteoporotic spine. The T10 screws were not over-drilled but cemented so as to keep the superior segments constant. Flexibility tests were first carried out on the intact specimen, followed by 3 randomized surgical conditions without cement and lastly the 3 conditions after cement augmentation. The 3 conditions were: 1) no posterior extension rods to L1, 2) flexible extension rods, and 3) rigid extension rods. A combined testing/analysis protocol that used both the traditional flexibility method and a hybrid technique [Panjabi 2005] was adopted. Flexibility tests with +/−5 Nm pure moments in flexion-extension, axial rotation and lateral bending were carried out and vertebral bodies’ motion in 3-D were collected. Two-way repeated measures ANOVA analyses were carried out on ROM between cement augmentation (factor 1) and the posterior rod extension (factor 2) on each flexibility test direction. An alpha of 0.05 was chosen. Newman-Keuls post-hoc analyses were carried out to compare between surgical techniques.

Results: Using the flexibility protocol, a reduction in ROMs at the destabilized level was observed with cement augmentation of screws or extension with rigid or flexible posterior rods to adjacent distal level. With the hybrid protocol, ROMs at adjacent level (T12-L1) were reduced with rod extension, but not with cement.

Conclusions: The results of this study suggest that cement augmentation would enhance stabilization, but create possible adjacent level effects due to increased motion and strain, while additional flexible extension rods would reduce biomechanical changes at the level of extension. Funding: 2 Funding Parties: CIHR

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.