Evidence-based Spine-care Journal[JOURNAL]
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186 papers
Diagnosis and treatment of craniocervical dissociation in 48 consecutive survivors.
Reis A, Bransford R, Penoyar T … +2 more , Chapman JR, Bellabarba C
Evid Based Spine Care J · 2010 Aug · PMID 23637673 · Full text
STUDY TYPE: Case series Introduction: Craniocervical dissociation (CCD) is an uncommon and frequently fatal injury with few reports in the literature of survivors. Advances in automobile safety and improved emergency m...
STUDY TYPE: Case series Introduction: Craniocervical dissociation (CCD) is an uncommon and frequently fatal injury with few reports in the literature of survivors. Advances in automobile safety and improved emergency medical services have resulted in increased survival. Timely diagnosis and treatment are imperative for optimal outcome. Regrettably, the presence of multiple life threatening injuries, low clinical suspicion, and lack of familiarity with the upper cervical radiographic anatomy frequently lead to missed or delayed diagnosis. OBJECTIVE: This paper represents the largest series of surgically treated CCD survivors. The goal of this study is to determine if any improvements have been made in the timely diagnosis of CCD while performing a complete patient evaluation. METHODS: Following institutional review board approval, a search of the Harborview Medical Center (HMC) trauma registry was conducted for all surgically treated CCD patients between 1996 and 2008. Forty-eight consecutive cases were identified. A retrospective review of the radiological and clinical results with emphasis on timing of diagnosis, modality used for diagnosis (Figures 1 and 2), clinical effect of delayed diagnosis, potential clinical or imaging warning signs, and response to treatment was performed. Thirty-one patients treated from 2003 to 2008 were compared to 17 patients that were treated from 1996 to 2002 and reported previously.1 Figure 1 Initial lateral C-spine radiograph obtained as part of the initial ATLS survey demonstrating an occiput C1 distractive injury.Figure 2 Sagittal C-spine CT scan obtained as part of the initial ATLS survey demonstrating an occiput C2 distractive injury. All patients sustained high-energy injuries and were evaluated according to standard Advanced Trauma Life Support (ATLS) protocols. Once CCD was identified or suspected, provisional stabilization was applied and MRI evaluation performed (Figure 3). Definitive surgical management with rigid posterior instrumentation and fusion was performed as soon as physiologically possible (Figures 4 and 5). Figure 3a-b Preoperative coronal T2 MRI sequences demonstrating increased signal intensity on the occiput-C1 and C1-2 joints.Figure 4 Postoperative lateral C-spine x-ray showing rigid posterior instrumented fusion from occiput to C2.Figure 5 Postoperative sagittal C-spine x-ray showing rigid posterior instrumented fusion from occiput to C2. RESULTS: Craniocervical dissociation was identified on initial cervical spine imaging in 26 patients (84%). The remaining five patients (16%) were diagnosed by cervical spine MRI. Twenty-three patients (74.2%) were diagnosed within 24 hours of presentation, four (22.6%) were diagnosed between 24 and 48 hours, and one (3.2%) experienced a delay of greater than 48 hours (Table 1). In comparison, four (24%) of the previously treated 17 patients were diagnosed on initial cervical spine imaging. Four patients (24%) were diagnosed within 24 hours of presentation, nine (52%) were diagnosed between 24 and 48 hours, and four (24%) experienced a delay of greater than 48 hours. There were no cases of craniocervical pseudarthrosis or hardware failure during a mean nine-month follow-up period. Four patients expired during their hospital course. The mean American Spinal Injury Association (ASIA) motor score of 47 improved to 60, and the number of patients with useful motor function (ASIA Grade D or E) increased from eight (26%) preoperatively to 17 (55%) postoperatively. CONCLUSIONS: Improvements have been made in time to diagnosis of CCD in recent years. Increased awareness and the routine use of CT scan as part of the initial ATLS evaluation account for this progress. Expedited diagnosis has decreased preoperative neurological deterioration. However, differences in length of follow-up between the two groups preclude conclusions about its effect on long-term neurological outcome. [Table: see text].
Development of a whole disc organ culture system to study human intervertebral disc.
Parolin M, Gawri R, Mwale F … +6 more , Steffen T, Roughley P, Antoniou J, Jarzem P, Haglund L, Ouellet J
Evid Based Spine Care J · 2010 Aug · PMID 23637672 · Full text
STUDY TYPE: Basic science Objective: Low back pain is one of the most common health problems1 and is strongly associated with intervertebral disc degeneration, (IVD). Current treatments remove the symptoms without reve...
STUDY TYPE: Basic science Objective: Low back pain is one of the most common health problems1 and is strongly associated with intervertebral disc degeneration, (IVD). Current treatments remove the symptoms without reversing or even retarding the underlying problem. Development of new therapy for the regeneration of the degenerative IVD is complicated by the lack of a validated long-term organ culture model in which therapeutic candidates can be studied. The object of this study was to develop, optimize, and validate an organ culture model for human IVD, allowing for the study of degeneration and the potential for regeneration of the human IVD. METHODS: From eleven donors, an average of 5-6 IVDs were obtained. Inclusion criteria were; age between 50 and 70 years old, no history of cancer, chemotherapy, diabetes, or liver cirrhosis. An x-ray of the harvested spine was done to assess the grade of degeneration. Three different methods for isolating the discs were studied: with bony endplate (BEP), without endplate (NEP), and with cartilage endplate (CEP). Discs were cultured for 4 weeks without external load, in Dulbecco's modified eagle media with glucose and fetal bovine serum (FBS). Four different combinations of concentrations of glucose and FBS were compared: low glucose-low FBS, low glucose-high FBS, high glucose-low FBS, and high glucose-high FBS.2 Short-term cultures (1 week) were performed to compare the cell viability of the three methods of isolating the discs. Swelling potential on NEP and CEP discs from the same donor were evaluated. After four weeks of culture, a 4 mm punch was taken from CEP discs and cell viability was evaluated using a live/dead assay with confocal microscopy. RESULTS: Analyzing the potential of swelling in CEP discs, there was an increase in volume to a maximum of 25% and retention of shape and morphology. Whereas in NEP discs, there was an excessive deformation and a two-fold time increase in volume than CEP discs. The cell viability in short-term cultures is around 40%-50% in the BEP model, 50%-60% in the NEP model and > 96% in the CEP model. BEP isolated discs show endplate necrosis that begins after 4 days of culture. Cell viability in CEP discs was evaluated at 4 weeks in three different areas of the disc: nucleus pulposus, inner annulus fibrosus, and outer annulus fibrosus. We found no difference in live cells (> 96%) between the four different concentrations of FBS and glucose (Table 1). [Table: see text] CONCLUSIONS: We have developed a novel method to isolate human IVDs and optimized the culture conditions. The CEP method has been proven to be superior to the previous models (NEP and BEP) in cell viability and maintaining physiologic swelling.3 In the long-term cultures, the CEP system maintained sufficient nutrient supply and high cell survival in all regions of the discs even with low concentrations of FBS and glucose. The availability of an intact disc organ culture system has a considerable advantage over the culture of isolated disc cells, as it maintains the cells in their unique microenvironment, making any response to catabolic or anabolic agents more physiologically relevant.
Total disc replacement using a tissue-engineered intervertebral disc in vivo: new animal model and initial results.
Gebhard H, Bowles R, Dyke J … +4 more , Saleh T, Doty S, Bonassar L, Härtl R
Evid Based Spine Care J · 2010 Aug · PMID 23637671 · Full text
STUDY TYPE: Basic science Introduction: Chronic back pain due to degenerative disc disease (DDD) is among the most important medical conditions causing morbidity and significant health care costs. Surgical treatment op...
STUDY TYPE: Basic science Introduction: Chronic back pain due to degenerative disc disease (DDD) is among the most important medical conditions causing morbidity and significant health care costs. Surgical treatment options include disc replacement or fusion surgery, but are associated with significant short- and long-term risks.1 Biological tissue-engineering of human intervertebral discs (IVD) could offer an important alternative.2 Recent in vitro data from our group have shown successful engineering and growth of ovine intervertebral disc composites with circumferentially aligned collagen fibrils in the annulus fibrosus (AF) (Figure 1).3 Figure 1 Tissue-engineered composite disc a Experimental steps to generate composite tissue-engineered IVDs3b Example of different AF formulations on collagen alignment in the AF. Second harmonic generation and two-photon excited fluorescence images of seeded collagen gels (for AF) of 1 and 2.5 mg/ml over time. At seeding, cells and collagen were homogenously distributed in the gels. Over time, AF cells elongated and collagen aligned parallel to cells. Less contraction and less alignment is noted after 3 days in the 2.5 mg/mL gel. c Imaging-based creation of a virtual disc model that will serve as template for the engineered disc. Total disc dimensions (AF and NP) were retrieved from micro-computer tomography (CT) (left images), and nucleus pulposus (NP) dimensions alone were retrieved from T2-weighted MRI images (right images). Merging of MRI and micro-CT models revealed a composite disc model (middle image)-Software: Microview, GE Healthcare Inc., Princeton, NJ; and slicOmatic v4.3, TomoVision, Montreal, Canada. d Flow chart describing the process for generating multi-lamellar tissue engineered IVDs. IVDs are produced by allowing cell-seeded collagen layers to contract around a cell-seeded alginate core (NP) over time Objective: The next step is to investigate if biological disc implants survive, integrate, and restore function to the spine in vivo. A model will be developed that allows efficient in vivo testing of tissue-engineered discs of various compositions and characteristics. METHODS: Athymic rats were anesthetized and a dorsal approach was chosen to perform a microsurgical discectomy in the rat caudal spine (Fig. 2,Fig. 3). Control group I (n = 6) underwent discectomy only, Control group II (n = 6) underwent discectomy, followed by reimplantation of the autologous disc. Two treatment groups (group III, n = 6, 1 month survival; group IV, n = 6, 6 months survival) received a tissue-engineered composite disc implant. The rodents were followed clinically for signs of infection, pain level and wound healing. X-rays and magnetic resonance imaging (MRI) were assessed postoperatively and up to 6 months after surgery (Fig. 6,Fig. 7). A 7 Tesla MRI (Bruker) was implemented for assessment of the operated level as well as the adjacent disc (hydration). T2-weighted sequences were interpreted by a semiquantitative score (0 = no signal, 1 = weak signal, 2 = strong signal and anatomical features of a normal disc). Histology was performed with staining for proteoglycans (Alcian blue) and collagen (Picrosirius red) (Fig. 4,Fig. 5). Figure 2 Disc replacement surgery a Operative situs with native disc that has been disassociated from both adjacent vertebrae b Native disc (left) and tissue-engineered implant (right) c Implant in situ before wound closureAF: Annulus fi brosus, nP: nucleus pulposus, eP: endplate, M: Muscle, T: Tendon, s: skin, art: artery, GP: Growth plate, B: BoneFigure 3 Disc replacement surgery. Anatomy of the rat caudal disc space a Pircrosirius red stained axial cut of native disc space b Saffranin-O stained sagittal cut of native disc spaceFigure 4 Histologies of three separate motion segments from three different rats. Animal one = native IVD, Animal two = status after discectomy, Animal three = tissue-engineered implant (1 month) a-c H&E (overall tissue staining for light micrsocopy) d-f Alcian blue (proteoglycans) g-i Picrosirius red (collagen I and II)Figure 5 Histology from one motion segment four months after implantation of a bio-engineered disc construct a Picrosirius red staining (collagen) b Polarized light microscopy showing collagen staining and collagen organization in AF region c Increased Safranin-O staining (proteoglycans) in NP region of the disc implant d Higher magnification of figure 5c: Integration between implanted tissue-engineered total disc replacement and vertebral body boneFigure 6 MRI a Disc space height measurements in flash/T1 sequence (top: implant (714.0 micrometer), bottom: native disc (823.5 micrometer) b T2 sequence, red circle surrounding the implant NPFigure 7 7 Tesla MRI imaging of rat tail IVDs showing axial images (preliminary pilot data) a Diffusion tensor imaging (DTI) on two explanted rat tail discs in Formalin b Higher magnification of a, showing directional alignment of collagen fibers (red and green) when compared to the color ball on top which maps fibers' directional alignment (eg, fibers directing from left to right: red, from top to bottom: blue) c Native IVD in vivo (successful imaging of top and bottom of the IVD (red) d Gradient echo sequence (GE) showing differentiation between NP (light grey) and AF (dark margin) e GE of reimplanted tail IVD at the explantation level f T1Rho sequence demonstrating the NP (grey) within the AF (dark margin), containing the yellow marked region of interest for value acquisition (preliminary data are consistent with values reported in the literature). g T2 image of native IVD in vivo for monitoring of hydration (white: NP) Results: The model allowed reproducible and complete discectomies as well as disc implantation in the rat tail spine without any surgical or postoperative complications. Discectomy resulted in immediate collapse of the disc space. Preliminary results indicate that disc space height was maintained after disc implantation in groups II, III and IV over time. MRI revealed high resolution images of normal intervertebral discs in vivo. Eight out of twelve animals (groups III and IV) showed a positive signal in T2-weighted images after 1 month (grade 0 = 4, grade 1 = 4, grade 2 = 4). Positive staining was seen for collagen as well as proteoglycans at the site of disc implantation after 1 month in each of the six animals with engineered implants (group III). Analysis of group IV showed positive T2 signal in five out of six animals and disc-height preservation in all animals after 6 months. CONCLUSIONS: This study demonstrates for the first time that tissue-engineered composite IVDs with circumferentially aligned collagen fibrils survive and integrate with surrounding vertebral bodies when placed in the rat spine for up to 6 months. Tissue-engineered composite IVDs restored function to the rat spine as indicated by maintenance of disc height and vertebral alignment. A significant finding was that maintenance of the composite structure in group III was observed, with increased proteoglycan staining in the nucleus pulposus region (Figure 4d-f). Proteoglycan and collagen matrix as well as disc height preservation and positive T2 signals in MRI are promising parameters and indicate functionality of the implants.
Intraoperative neuromonitoring: lessons learned from 32 case events in 2095 spine cases.
Eager M, Jahangiri F, Shimer A … +2 more , Shen F, Arlet V
Evid Based Spine Care J · 2010 Aug · PMID 23637670 · Full text
STUDY TYPE: Restrospective chart review Introduction: Intraoperative neuromonitoring is becoming the standard of care for many more spinal surgeries, especially with deformity correction and instrumentation. We reviewe...
STUDY TYPE: Restrospective chart review Introduction: Intraoperative neuromonitoring is becoming the standard of care for many more spinal surgeries, especially with deformity correction and instrumentation. We reviewed our institution's neuromonitored spine cases over the past 4 years to see the immediate intraoperative and postoperative clinical findings when an intraoperative neuromonitoring event was noted. OBJECTIVE: The main question addressed in this review is how multimodality intraoperative neuromonitoring has affected our ability to avoid potential neurological injury during spine surgery. METHODS: We retrospectively reviewed 2,095 neuromonitored spine cases at one institution performed over a period of 4 years. Data from the single neuromonitoring provider (Impulse Monitoring, Inc.) at our institution was collected and any cases with possible intraoperative events were isolated. The intraoperative and immediate postoperative clinical documentation of these 32 cases were reviewed (Table 1). [Table: see text] RESULTS: There were 17 cases where changes noted on EMG, SSEP, and/or MEPs affected the course of the surgery, and prevented possible postoperative neurological deficits. Of these 17, five were related to hypotension, seven due to deformity correction, one screw had a low triggered EMG threshold and was repositioned, and four cases had changes related to patient positioning and external pressure (ie, brachial plexus stretch). None of the 17 cases had postoperative motor or sensory deficits (Figure 1). Figure 1 DURING THE INSERTION OF THE CONVEX ROD: decrease of the MEP amplitude in left foot by 80% amplitude (yellow arrow). The baseline recording is in blue, the current recording in purple. The right side (non represented) will remain normal. Four cases consisted of intradural cord biopsies or tumor resections that had various positive neuromonitoring findings that essentially serve as controls. These cases confirm that the expected changes were seen on neuromonitoring. Four cases had false-positive neuromonitoring findings due to one technical issue requiring needle repositioning, one low threshold with triggered EMG without a pedicle breach, one case had decreased MEP responses with stable SSEPs, and one case had decreased SSEPs after positioning the patient prone. None of these four cases had any postoperative deficits. Four cases showed improved SSEPs after decompression; three cervical corpectomies, and one thoracic discectomy. Three cases of lumbar instrumentation with spontaneous EMGs each had a medial screw breach without intraoperative findings (Figure 2). They all had a postoperative motor deficit (foot drop). None of these three cases had triggered EMGs performed with the index procedure. Figure 2 Left L4 pedicle screw medial breach. Triggered EMGs were not performed during the index procedure. Postoperative foot drop required a second surgery to reposition the screw. CONCLUSIONS: Overall, this review reinforces the importance of multimodality neuromonitoring for spinal surgery. The incidence of possible events in our series was 1.5%. It is difficult to determine the true incidence, since it is impossible to know of any missed events due to lack of complete documentation. In a majority of the cases with events, possible postoperative neurologic deficits were avoided by intraoperative intervention, but the possible outcomes without intervention are not known. Clearly, in the three cases with lumbar pedicle screw malposition, triggered EMGs would have likely shown low thresholds. This would allow for screw reposition, and thus avoid a postoperative lumbar radiculopathy and revision surgery. The incidence of false-positive findings was very low in this review, and unfortunately the true incidence of false-negative findings is not able to be elucidated with this database.
Accuracy and reliability of MRI quantitative measurements to assess spinal cord compression in cervical spondylotic myelopathy: a prospective study.
Karpova A, Craciunas S, Chua SY … +3 more , Rabin D, Smith S, Fehlings MG
Evid Based Spine Care J · 2010 Aug · PMID 23637669 · Full text
STUDY TYPE: Reliability study Introduction: Cervical spondylotic myelopathy (CSM) is the most common spinal cord disorder in persons more than 55 years old. Despite multiple neuroimaging approaches proposed to quantify...
STUDY TYPE: Reliability study Introduction: Cervical spondylotic myelopathy (CSM) is the most common spinal cord disorder in persons more than 55 years old. Despite multiple neuroimaging approaches proposed to quantify the spinal cord compromise in CSM patients, magnetic resonance imaging (MRI) remains the procedure of choice by providing helpful information for clinical decision making, determining optimal subpopulations for treatment, and selecting the optimal treatment strategies. However, the validity, reliability, and accuracy of the MRI quantitative measurements have not yet been addressed. OBJECTIVE: To assess the intra- and inter-observer reliability of MRI quantitative measurements of the spinal cord compromise in CSM patients. METHODS: Seventeen CSM patients (13 male) of mean age 54.5 years old were selected from the AOSpine North America database. The patients had different combinations of stenotic levels (1-4 levels) and the clinical severity (range mJOA baseline: 8-18). Asymptomatic or previous surgically treated CSM, active infection, neoplastic disease, rheumatoid arthritis, ankylosing spondylitis, trauma, or concomitant lumbar stenosis were excluded. The patients underwent preoperative MRI using 1.5T (15 patients) and 3T (two patients) scanner, including mid-sagittal T1-weighted, axial and mid-sagittal T2-weighted series. MRI data were analyzed (Mango 2.0 software; Multi-Image Analysis GUI) by four blind raters in three different sessions. Four measurements were analysed: transverse area (TA) (Figure 1), compression ratio (CR) (Figure 2), maximal canal compromise (MCC), and maximal spinal cord compression (MSCC) (Figure 3). The differences for each measurement were evaluated using mixed-effect ANOVA models (ratter, session, ratter x session). The intra- and inter-rater reliability was evaluated with intraclass correlation coefficients (ICC) (Figure 4). Figure 1 Transverse area (TA)Figure 2 Compression ratio (CR = AP/W)Figure 3 Maximal canal compromise (MCC), and maximal spinal cord compression (MSCC). MCC(%) = 1-[Dx/(Da+Db)/2] × 100%; MSCC(%) = 1-[dx/(da+db)/2] × 100%Figure 4 Intraclass correlation coefficients (ICC) Results: The principal findings were: (i) for TA (71.48 ± 12.99mm2), the intra-rater agreement was 0.97 (95% CI, range 0.94-0.99) and the inter-rater agreement was 0.76 (95% CI, range 0.49-0.90); (ii) for CR (0.35 ± 0.04%), 0.94 (95% CI, range 0.88-0.98), and 0.79 (95% CI, range 0.57-0.91) respectively; (iii) for MCC (83.21 ± 2.08%), 0.95 (95% CI, range 0.89-0.98), and 0.64 (95% CI, range 0.28-0.85) respectively; and (iv) for MSCC (82.87 ± 1.52%), 0.93 (95% CI, range 0.86-0.97), and 0.84 (95% CI, range 0.65-0.93) respectively. CONCLUSIONS: Our data suggest that three out of four measurements (TA, CR and MSCC) have acceptable intra- and interreliability coefficients (ICC > 0.75). However, for the maximal canal compromise measure, although the intrareliability was acceptable, the inter-rater reliability was not acceptable (0.64). Based on this study, we recommend that three MRI measures: transverse area, compression ratio and maximal spinal cord compression should be used in the imaging assessment of the spinal cord in CSM patients.
Traumatic neuroma in continuity injury model in rodents: a preliminary report.
Alant J, Kemp S, Webb A … +1 more , Midha R
Evid Based Spine Care J · 2010 Aug · PMID 23637668 · Full text
UNLABELLED: Consistent with EBSJ's commitment to fostering quality research, we are pleased to feature some of the most highly rated abstracts from the 8th Annual AOSpine North America Fellows Forum in Banff Canada. Enha...
UNLABELLED: Consistent with EBSJ's commitment to fostering quality research, we are pleased to feature some of the most highly rated abstracts from the 8th Annual AOSpine North America Fellows Forum in Banff Canada. Enhancing the quality of evidence in spine care means acknowledging and supporting the efforts of young researchers within our AOSpine North America network. We look forward to seeing more from these promising researchers in the future. STUDY TYPE: Basic science research report Introduction: Spinal nerve-injury management and prevention constitute a substantial proportion of a spinal surgeon's practice. Functional recovery after peripheral nerve injuries is often unsatisfactory and to optimize the outcomes, an intimate understanding of these injuries is required. Sunderland classified peripheral nerve injuries into five grades.1 Grade 1 (neurapraxia) and grade 2 (axonal disruption) injuries usually recover with no or insignificant functional deficits within weeks to a few months, respectively. Injuries that are most difficult to manage clinically are the often mixed grade 3 (endoneurial disruption) and grade 4 (perineurial disruption) lesions where spontaneous functional recovery is limited or absent, resulting in neuroma in continuity (NIC). Traumatic NIC is characterized by aberrant intra- and extra- fascicular axonal regeneration and scar formation within an unsevered injured nerve, resulting in impaired and erroneous end-organ reinnervation.2,3 Animal models reproducing grade 1, 2, 3, and 5 lesions have been developed, but to our knowledge a clinically relevant rodent model of NIC has not been developed.4,5,6,7,8 The effective peripheral nerve regeneration and resilience of rodents make it challenging to recreate the NIC scenario. OBJECTIVE: Our goal was to develop a practical rodent model for focal traumatic NIC, demonstrating the characteristic histological features, supported by concordant functional deficits. Such a model may help us to identify this injury pattern earlier and allow development of intervention strategies to reduce neuronal misdirection, scar formation, and enhance regeneration for improved functional recovery. METHODS: Various injury techniques were tested on freshly harvested Lewis rat sciatic nerves ex vivo, and examined histologically before inflicting more refined injuries in vivo. The optimal experimental injuries combined a 50 g traction force applied with a spring scale hooked around the sciatic nerve, and focal three second maximal compression using a malleus nipper (Figure 1). Nerves were harvested at 0, 5, 13, 21, and 65 days, and processed for longitudinal 8 micron cryostat sectioning, H&E, laminin, neurofilament, and Masson's trichrome staining. Skilled locomotion (tapered beam, ladder rung) and flat plane locomotion for ground reaction force (GRF) analysis were performed serially up to 9 weeks with the experimental (n = 4) and simple (control) crush (n = 1) injuries by blinded animal behavior experts, using methods as recently described.9 Figure 1 Photograph illustrating the experimental injury. Fifty grams of traction is applied in a direction orthogonal to the native nerve course after external neurolysis, simultaneously, three second maximal compression is applied at the sciatic trifurcation, just distal to a mesoneurial suture. Malleus nipper with tip detail and 100 g spring scale in bottom left. In situ sciatic nerve immediately after injury (top right). RESULTS: Disruption of the endoneurium and perineurium with aberrant intra- and extrafascicular axonal regeneration and progressive fibrosis was consistently demonstrated histologically in ten out of ten nerves with experimental injuries. In contrast, crush injuries showed only signs of Wallerian degeneration (Figure 2). At 8 weeks, experimental animals made more errors during skilled locomotion as compared to nerve crush animals. GRFs revealed impaired vertical and fore-aft force generation by the injured limbs at week 9 in the experimental group, whereas GRFs from the simple crush animal revealed recovery at the same time point (Figure 3). Figure 2 Injury zones at five days (a-d, bar = 200 µm) and 65 days (e-h, bar = 50 µm), comparing crush (top) to experimental (bottom) injuries; Masson's trichrome and neurofilament. Note the aberrant axonal sprouting and regeneration in the experimental injury group, associated with increased intrafascicular collagen, in contrast to orderly regeneration and lack of scar in the simple crush group.Figure 3 Mean vertical and fore-aft ground reaction forces at both baseline and 9 weeks from representative animals. Compared to baseline and crush-injured animal at 9 weeks, animals in the experimental group bear less weight on both their right (surgical) hind limb (solid line), and fore limb (dotted line) at 9 weeks. Comparable with historical data, the crush animal have improved braking ((*)) and propulsive (#) forces in fore and hind limbs (injured side) compared to the experimental group, though these have not returned to baseline values. CONCLUSIONS: We have demonstrated histological features and poor functional recovery consistent with NIC formation in a rodent model. The injury mechanism employed combines traction and compression forces akin to the physical forces at play in clinical nerve injuries. Additional validating experiments are in progress.
Arachnoiditis ossificans associated with syringomyelia: An unusual cause of myelopathy.
Ibrahim GM, Kamali-Nejad T, Fehlings MG
Evid Based Spine Care J · 2010 Aug · PMID 23637667 · Full text
OBJECTIVE: The pathophysiology of arachnoiditis ossificans (AO) and its association with syringomyelia remains a rare and poorly understood phenomenon. Here, we present a case of AO associated with syringomyelia, a revi...
OBJECTIVE: The pathophysiology of arachnoiditis ossificans (AO) and its association with syringomyelia remains a rare and poorly understood phenomenon. Here, we present a case of AO associated with syringomyelia, a review of literature, and a discussion of current understanding of disease pathophysiology. METHODS: A literature review was performed using MEDLINE (January 1900-May 2010) and Embase (January 1900-May 2010) to identify all English-language studies that described AO with syringomyelia. The current report was added to published cases. RESULTS: Over 50 cases of AO are reported in literature, of which only eight are associated with syringomyelia. The various presumptive etiologies of syrinx formation include abnormalities in blood circulation, ischemia, hydrodynamic alternations in cerebrospinal fluid (CSF) flow, tissue damage, or incidental coexistence. Changing CSF dynamics related to decreased compliance of the subarachnoid space and subsequent paracentral dissection of the spinal cord may be implicated in the disease process. magnetic resonance imaging (MRI) scanning may identify the syrinx but fail to diagnose the calcified arachnoid. Five patients, including the current case, improved clinically following laminectomy and decompression. CONCLUSIONS: Syringomyelia in association in AO is a rare phenomenon. A high index of suspicion is required and both MRI and computed tomography (CT) are recommended for diagnosis. The pathophysiology of syringomyelia in AO remains an area of ongoing research.
Is chemical antithrombotic prophylaxis effective in elective thoracolumbar spine surgery? Results of a systematic review.
Schuster JM, Fischer D, Dettori JR
Evid Based Spine Care J · 2010 Aug · PMID 23637666 · Full text
STUDY DESIGN: Systematic review Study rationale and context: There is controversy regarding the efficacy and safety of chemical prophylaxis to prevent deep venous thrombosis (DVT) and pulmonary embolism (PE) in electiv...
STUDY DESIGN: Systematic review Study rationale and context: There is controversy regarding the efficacy and safety of chemical prophylaxis to prevent deep venous thrombosis (DVT) and pulmonary embolism (PE) in elective spinal procedures.Commonly performed elective spine surgeries done through a posterior approach have a very low associated risk of DVT/PE. The lack of consensus is due in part to a limited amount of quality evidence based literature dealing with this issue. OBJECTIVE: To compare chemical prophylaxis with no chemical prophylaxis in preventing venous thromboembolism in elective thoracolumbar spine surgery. METHODS: We undertook a systematic review of the literature to assess the efficacy and safety of chemical prophylaxis in preventing venous thromboembolism in elective thoracolumbar spine surgery. Pubmed, EMBASE, Cochrane, National Guideline Clearinghouse Databases as well as bibliographies of key articles were searched. Articles were reviewed by two independently working reviewers. Inclusion and exclusion criteria were set and each article was subject to a predefined quality rating scheme. RESULTS: We identified only two articles meeting our inclusion criteria. Neither study demonstrated a significant difference between chemical prophylaxis versus no prophylaxis in preventing thromboembolic events. There was an increased incidence of perioperative bleeding with low dose Coumadin in one of the studies. CONCLUSION: The incidence of DVT and PE in commonly performed elective posterior spinal procedures is very low. While there is a limited amount of randomized literature looking at this issue, the current literature does not support the routine use of chemical prophylaxis for low risk patients undergoing these procedures.
Does lumbar decompression in overweight patients assist in postoperative weight loss?
Anderson PA, Dettori JR, Hermsmeyer JT
Evid Based Spine Care J · 2010 Aug · PMID 23637665 · Full text
STUDY DESIGN: Systematic review. OBJECTIVE: To determine if there is a weight change in overweight patients following lumbar decompression with or without fusion for lumbar degenerative conditions. SUMMARY OF BACKGROUN...
STUDY DESIGN: Systematic review. OBJECTIVE: To determine if there is a weight change in overweight patients following lumbar decompression with or without fusion for lumbar degenerative conditions. SUMMARY OF BACKGROUND: Anecdotal evidence suggests obesity is a risk factor for recurrent disc herniation or adjacent segment degeneration after lumbar surgery. Weight loss after surgery therefore may be important to reduce risk of these problems. Theoretically, patients who recover may be able to increase exercise tolerance and therefore the possibility for weight loss is more likely. If spine patients are similar to knee arthroplasty then it is unlikely that substantial weight loss will occur after surgery. If true, then other patient centered programs need to be developed to help obese patient's loss weight after spine surgery. METHODS: A systematic review of the English language literature was undertaken for articles published between 1970 and March 2010. Electronic databases and reference lists of key articles were searched to identify studies evaluating weight change in overweight patients following lumbar decompression with or without fusion for lumbar degenerative conditions. Two independent reviewers assessed the strength of evidence using the GRADE criteria assessing quality, quantity, and consistency of results. Disagreements were resolved by consensus. RESULTS: We identified two articles meeting our inclusion criteria. Body weight change following lumbar surgery in overweight patients varied between the two included studies. One study reported 6% of patients lost weight 34 months following lumbar surgery, while 35% gained body weight. A second study reported 40% lost weight while 41% gained weight 20 months post surgery. Evidence from these two studies are limited due to small sample sizes, different definitions of overweight, and unequal lengths of follow up between the two studies. CONCLUSION: There is no evidence that overweight patients consistently lose weight as a result of lumbar decompression with or without fusion. Two small studies suggest that an overweight patient undergoing lumbar surgery is as likely to gain weight as to lose weight following surgery.
Risk factors for pulmonary complications after spine surgery.
Imposti F, Cizik A, Bransford R … +2 more , Bellabarba C, Lee MJ
Evid Based Spine Care J · 2010 Aug · PMID 23637664 · Full text
STUDY DESIGN: Registry study with prospectively collected data Objective: To determine risk factors for pulmonary complications in spine surgery. METHODS: The Spine End RESULTS Registry 2003-2004 is an exhaustive data...
STUDY DESIGN: Registry study with prospectively collected data Objective: To determine risk factors for pulmonary complications in spine surgery. METHODS: The Spine End RESULTS Registry 2003-2004 is an exhaustive database of 1,592 patients who underwent spine surgery at the University of Washington Medical Center or Harborview Medical Center. Detailed information regarding patient demographic, medical comorbidity, and comorbidities, surgical invasiveness and adverse outcomes were prospectively recorded. The primary outcome measure was the occurrence of a pulmonary complication following surgery. Univariate relative risks and 95% confidence intervals for each of the risk factors were determined. Multivariate log binomial regression analysis was performed to investigate the association between each risk factor and a pulmonary complication, while controlling for other important risk factors. RESULTS: Altogether, there were 199 pulmonary complications after spine surgery. The cumulative incidence of a respiratory complication after spine surgery was 9% (144 patients). Multivariate analysis suggested gender, chronic obstructive pulmonary disease, congestive heart failure, diabetes, age, diagnosis, surgical invasiveness and surgery in the thoracic spine are significant risk factors for pulmonary complications after spinal surgery. CONCLUSIONS: The results of the present study suggest numerous statistically significant risk factors for pulmonary complications after spine surgery. These results may aid the clinician with preoperative risk stratification and patient counseling. [Table: see text] The definiton of the different classes of evidence is available on page 73.
Risk factors for cardiac complications after spine surgery.
Guyot JP, Cizik A, Bransford R … +2 more , Bellabarba C, Lee MJ
Evid Based Spine Care J · 2010 Aug · PMID 23637663 · Full text
STUDY DESIGN: Registry study using prospectively collected data Objective: To determine risk factors for cardiac complications in spine surgery. METHODS: The Spine End RESULTS Registry 2003-2004 is an exhaustive datab...
STUDY DESIGN: Registry study using prospectively collected data Objective: To determine risk factors for cardiac complications in spine surgery. METHODS: The Spine End RESULTS Registry 2003-2004 is an exhaustive database of 1,592 patients who underwent spine surgery at the University of Washington Medical Center or Harborview Medical Center. Detailed information regarding patient demographic, medical comorbidity, surgical invasiveness and adverse outcomes were prospectively recorded. The primary outcome of measure was the occurrence of a cardiac complication in the perioperative period. Relative risk (RR) and 95% confidence intervals were calculated for each of the categorical variables. Multiple log-binomial regression analysis was performed to investigate the independent factors associated with cardiac complication. RESULTS: The incidence of cardiac complication after spine surgery was 6.7%. There were 136 cardiac complications in 107 patients after spine surgery. Age, diabetes, previous cardiac history, elevated adjusted Charlson comorbidity score, revision surgery, combined anterior-posterior approaches, and surgical invasiveness were statistically significant risk factors for cardiac complication after spine surgery. CONCLUSIONS: The results of the present study suggest numerous statistically significant risk factors for cardiac complications after spine surgery. These results may aid the clinician with preoperative risk stratification and patient counseling. [Table: see text] The definiton of the different classes of evidence is available on page 73.
The influence of anatomy (normal versus scoliosis) on the free-hand placement of pedicle screws: Is misplacement more frequent in patients with anatomical deformity?
Gruenberg M, Petracchi M, Valacco M … +1 more , Solá C
Evid Based Spine Care J · 2010 Aug · PMID 23637662 · Full text
STUDY DESIGN: Retrospective prognostic study. OBJECTIVE: To evaluate whether patients with anatomical deformity due to scoliosis have a higher frequency of inaccurate pedicle screw insertion and related complications u...
STUDY DESIGN: Retrospective prognostic study. OBJECTIVE: To evaluate whether patients with anatomical deformity due to scoliosis have a higher frequency of inaccurate pedicle screw insertion and related complications using the free-hand technique compared with those whose normal anatomy had been impacted by trauma. METHODS: Consecutively treated trauma patients with otherwise normal anatomy (48 patients instrumented with 291 screws, group A) and scoliosis patients (24 patients instrumented with 287 screws, group B) were evaluated. Screw position on CT was evaluated using the classification by Gertzbein and Robbins with modification by Karagoz Guzey. (See web appendix at www.aospine.org/ebsj for complete classification description.) Images were examined by two fellows and one junior staff member none of whom participated in patient management. Screw position was determined by consensus. RESULTS: In group A, five (1.7%) out of 289 screws were severely misplaced and 26 (9%) screws caused either medial (3.8%) or lateral (5.2%) cortical breeches. The other 258 (89.3%) screws were fully contained within the cortical boundaries of the pedicle. In group B, seven (2.8%) out of 256 screws were severely misplaced. Thirty-three (13%) screws caused cortical breeches, either medial (9%), lateral (2%), or anterior (2%), and 216 (84.3%) screws were fully contained within the cortical boundaries of the pedicle and the vertebra. Neurological complications were reported in one patient with scoliosis. No vascular complications were reported in either group. CONCLUSIONS: The percentage of incorrectly placed screws was similar in both groups, trauma and deformity patients. The presence of vertebral anatomical changes related to adult scoliosis was not associated with an increase in the screw-related neurological or vascular complications. [Table: see text] The definiton of the different classes of evidence is available on page 73.
Study types and bias-Don't judge a study by the abstract's conclusion alone.
Norvell DC
Evid Based Spine Care J · 2010 Aug · PMID 23637661 · Full text
Abstract loading — click title to view on PubMed.
"Building a foundation of trust".
Chapman J
Evid Based Spine Care J · 2010 Aug · PMID 23637660 · Full text
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Metachronous presentation of metastasis from renal cell carcinoma: evaluation and management of spinal metastasis.
Patt JC, Kneisl JS
Evid Based Spine Care J · 2010 May · PMID 23544028 · Full text
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Addressing the challenges and controversies of managing os odontoideum: results of a systematic review.
Wilson JR, Dettori JR, Vanalstyne EM … +1 more , Fehlings MG
Evid Based Spine Care J · 2010 May · PMID 23544027 · Full text
INTRODUCTION: Os odontoideum is a rare condition with a controversial pathogenesis and poorly understood natural history. As a result, it is difficult for clinicians to predict which patients require surgical fusion to...
INTRODUCTION: Os odontoideum is a rare condition with a controversial pathogenesis and poorly understood natural history. As a result, it is difficult for clinicians to predict which patients require surgical fusion to prevent symptomatic progression and potentially devastating neurologic injury. METHODS: We undertook a systematic review of the literature to evaluate the clinical outcomes in the treatment of asymptomatic and symptomatic cases of os odontoideum. Pubmed, EMBASE, Cochrane, National Guideline Clearinghouse Databases as well as bibliographies of key articles were searched. Articles were reviewed by two independently working reviewers. Inclusion and exclusion criteria were set and each article was subject to a predefined quality rating scheme. RESULTS: We identified eleven articles meeting our inclusion criteria. Seven studies included patients with asymptomatic os odontoideum discovered incidentally from which it was possible to examine data on 18 individuals. Six studies were identified containing more than 15 patients with symptomatic os odontoideum. CONCLUSION: The existing literature regarding both asymptomatic or symptomatic os odontoideum and its treatment is very limited. No definitive conclusions can be drawn from these studies. A basic approach to the management of os odontoideum is offered based on the findings of this study.
Unilateral facet dislocations: Is surgery really the preferred option?
Dvorak M, Vaccaro AR, Hermsmeyer J … +1 more , Norvell DC
Evid Based Spine Care J · 2010 May · PMID 23544026 · Full text
STUDY DESIGN: Systematic review. OBJECTIVE: To compare the safety and effectiveness of initial surgery versus nonoperative management of unilateral facet dislocations with or without fractures. SUMMARY OF BACKGROUND: ...
STUDY DESIGN: Systematic review. OBJECTIVE: To compare the safety and effectiveness of initial surgery versus nonoperative management of unilateral facet dislocations with or without fractures. SUMMARY OF BACKGROUND: Unilateral facet injuries represent between 6%-10% of all cervical spine injuries and yet optimal treatment for these injuries has not been established. The surgeon is faced with the decision of whether to manage the injury operatively or nonoperatively. Providing evidence to support this decision is necessary and is the rationale behind this article. METHODS: A systematic review of the English language literature was undertaken for articles published between 1970 and August 2009. Electronic databases and reference lists of key articles were searched to identify studies evaluating surgery and nonoperative management of unilateral facet dislocations. Bilateral facet dislocations, isolated facet fractures (without dislocation), and complete spinal cord injuries were excluded. Two independent reviewers assessed the level of evidence quality using the GRADE criteria and disagreements were resolved by consensus. RESULTS: We identified six articles meeting our inclusion criteria. Treatment failure, neurological deterioration, and persistent pain occurred more frequently in patients treated nonoperatively versus patients treated with surgery. Surgical patients experienced infections and surgical related complications not experience by those managed nonoperatively. Patients treated surgically after failed nonoperative management also experienced better outcomes than those who continued to be managed nonoperatively. CONCLUSION: When faced with a patient requesting treatment recommendations for their acute unilateral facet dislocation, the surgeon can state that treatment failure, persistent pain, and neurological deterioration occur more frequently with nonoperative treatment based on the available literature. Ultimately it will be the preference of the patient that will decide between these two treatment approaches.
ProDisc-C versus fusion with Cervios chronOS prosthesis in cervical degenerative disc disease: Is there a difference at 12 months?
Vorsic M, Bunc G
Evid Based Spine Care J · 2010 May · PMID 23544025 · Full text
STUDY DESIGN: Prospective cohort study. OBJECTIVE: The aim of the study was to compare clinical results and to determine differences in outcomes between anterior cervical discectomy and fusion (ACDF) and disc arthropla...
STUDY DESIGN: Prospective cohort study. OBJECTIVE: The aim of the study was to compare clinical results and to determine differences in outcomes between anterior cervical discectomy and fusion (ACDF) and disc arthroplasty in patients treated for symptomatic cervical degenerative disc disease. METHODS: Forty patients with cervical degenerative disc disease were treated with ProDisc-C disc arthroplasty and 40 patients with fusion using an intervetebral spacer with integrated fixation (Cervios chronoOS) implants without additional anterior fixation. Fifty disc prostheses were placed in the first group and 52 intervertebral spacers were implanted in the second group. Clinical outcomes were assessed before and 12 months following the procedure using the neck disability index (NDI) and visual analog scale (VAS) for neck and arm pain, with 15% improvement in NDI and 20% in VAS defined as a clinically significant. RESULTS: Eighty patients with cervical degenerative disc disease with a mean age of 49.7 years were included in the study with a minimum follow-up of 12 months. The groups were similar at baseline both clinically and statistically (P > .05) except for age and VAS for arm pain. Both groups had a statistically significant improvement in NDI and VAS for neck and arm pain (P < .05) and the arthroplasty group had a better improvement according to NDI (74.3% of patients in the arthroplasty group achieved ≥15% improvement in NDI versus 65.7% of patients in ACDF group). CONCLUSIONS: Both ProDisc C and Cervios chronoOS prostheses resulted in significant pain reduction and functional outcome for the patients with slightly better results in the group treated with disc arthroplasty 12 months after the surgery. [Table: see text] The definiton of the different classes of evidence is available on page 83.
Kyphoplasty: Traditional imaging compared with computer-guided intervention-time to rethink technique?
Silverstein MP, Mac Millan M, Lieberman IH
Evid Based Spine Care J · 2010 May · PMID 23544024 · Full text
STUDY DESIGN: Equivalence trial (IRB not required for cadaveric studies). OBJECTIVE: To compare computer-guided and fluoroscopic kyphoplasty. Factors of interest were radiation exposure, position of cannula within pedi...
STUDY DESIGN: Equivalence trial (IRB not required for cadaveric studies). OBJECTIVE: To compare computer-guided and fluoroscopic kyphoplasty. Factors of interest were radiation exposure, position of cannula within pedicles and procedure time. METHODS: Kyphoplasty was performed on two cadavers. Computer-navigated, cross-sectional images from a cone-beam CT were used for one and fluoroscopic imaging for the other. In each, T6-9 and T11-L2 vertebrae were selected. For both imaging methods, anteroposterior and lateral x-rays were taken. Radiation exposure for both procedures was measured by four dosimeters. Procedure time, radiation to surgeon and cadaver, and position of cannula placement within pedicles were recorded. The surgeon wore one under the lead gown, another on the lead gown at shoulder level, and a third as a ring on the dominant hand. A dosimeter was also placed on the cadaver. RESULTS: The radiation from the cone-beam, computer-guided imaging system was 0.0 mrem to the surgeon and 0.52 rads to the cadaver. Using fluoroscopic imaging, surgeon's and cadaver's exposure was 5 mrem and 0.047 rads, respectively. Procedure times were similar and neither device resulted in cannula malposition. CONCLUSIONS: Cone-beam CT appears as accurate as the fluoroscopy; radiation exposure to the surgeon is eliminated, and radiation levels to the patient are acceptable.
Dynamic anterior cervical plating for multi-level spondylosis: Does it help?
Ragab AA, Hodges FS, Hill CP … +2 more , McGuire RA, Tucci M
Evid Based Spine Care J · 2010 May · PMID 23544023 · Full text
STUDY DESIGN: Randomized controlled trial. OBJECTIVE: To compare fusion rates, time to fusion, complication rates and subsidence between 1) a static, 2) a dynamic angulation, and 3) a dynamic translation plate in anter...
STUDY DESIGN: Randomized controlled trial. OBJECTIVE: To compare fusion rates, time to fusion, complication rates and subsidence between 1) a static, 2) a dynamic angulation, and 3) a dynamic translation plate in anterior cervical discectomy and fusion for symptomatic degenerative cervical disease. METHODS: Thirty-six patients with two level, symptomatic cervical degenerative changes requiring surgery were randomized in a blinded fashion to receive a statically locked plate, Cervical Spine Locking Plate (CSLP) (Synthes, Paoli, PN, USA), an Atlantis Vision(®) Anterior Cervical Plate System (Medtronic, Memphis, TN, USA) which allows angular dynamization, or a Premier(®) Anterior Cervical Plate System (Medtronic) which allows translational dynamization. Structured data collection and measurement protocols were used. Intervertebral composite allograft cages were used in all groups. Identical external immobilization and antiinflammatory medication protocols were followed. X-rays were obtained at preset time points postoperatively. Assessment of the primary outcomes was blinded. Rate of and time to fusion, graft/instrumentation complications, subsidence, and reoperation for adjacent level disease were measured. Paired t-test and three-way Analysis of Variance test (ANOVA) were used to assess statistical differences between groups. RESULTS: The three groups were similar demographically. Fusion rates in the CSLP, Atlantis and Premier plate groups were 100%, 91%, and 92% respectively. Mean time to fusion was 6.1, 8.3 and 6.3 months respectively but differences were not statistically significant. Mean subsidence in the groups was 1.9, 1.6, and 2.6 mm respectively. Subsidence was found even for the static (CSLP) plate, but no statistically significant differences were found. CONCLUSIONS: We found no clinical advantage of dynamic plates over static plates with regards to fusion rates, time to fusion, subsidence, complications, or adjacent-level surgery. Static plating allows for subsidence at similar levels to dynamic plating. [Table: see text] The definiton of the different classes of evidence is available on page 83.
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