Category: Spine

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Abnormal Findings on Magnetic Resonance Images of the Cervical Spines in 1211 Asymptomatic Subjects

Abnormal Findings on Magnetic Resonance Images of the Cervical Spines in 1211 Asymptomatic Subjects-1

Spine 2015;40:392–398

Study Design. Cross-sectional study.

Objective. The purpose of this study was to determine the prevalence and distribution of abnormal fi ndings on cervical spine magnetic resonance image (MRI).

Summary of Background Data. Neurological symptoms and abnormal findings on MR images are keys to diagnose the spinal diseases. To determine the significance of MRI abnormalities, we must take into account the (1) frequency and (2) spectrum of structural abnormalities, which may be asymptomatic. However, no large-scale study has documented abnormal fi ndings of the cervical spine on MR image in asymptomatic subjects.

Methods. MR images were analyzed for the anteroposterior spinal cord diameter, disc bulging diameter, and axial cross-sectional area of the spinal cord in 1211 healthy volunteers. The age of healthy volunteers prospectively enrolled in this study ranged from 20 to 70 years, with approximately 100 individuals per decade, per sex. These data were used to determine the spectrum and degree of disc bulging, spinal cord compression (SCC), and increased signal intensity changes in the spinal cord.

Results. Most subjects presented with disc bulging (87.6%), which signifi cantly increased with age in terms of frequency, severity,and number of levels. Even most subjects in their 20s had bulging discs, with 73.3% and 78.0% of males and females, respectively. In contrast, few asymptomatic subjects were diagnosed with SCC (5.3%) or increased signal intensity (2.3%). These numbers increased with age, particularly after age 50 years. SCC mainly involved 1 level (58%) or 2 levels (38%), and predominantly occurred at C5– C6 (41%) and C6–C7 (27%).

Conclusion. Disc bulging was frequently observed in asymptomatic subjects, even including those in their 20s. The number of patients with minor disc bulging increased from age 20 to 50 years. In contrast, the frequency of SCC and increased signal intensity increased after age 50 years, and this was accompanied by increased severity of disc bulging.

Level of Evidence: 2

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Computed Tomography-Based Image-Guided System in Spinal Surgery

Computed Tomography-Based Image-Guided System in Spinal Surgery

Operative Neurosurgery 11:59–68, 2015

Image-guided navigation systems (IGS) grant excellent clinical and radiological results, minimizing risks correlated with spinal instrumentation. However, there is some concern regarding the real need for IGS and its indications.

OBJECTIVE: To analyze the accuracy, technical aspect, and radiation exposure data of the principal IGS based on computed tomography (CT) imaging.

METHODS: The data of all patients treated for spinal instrumentation with the aid of an IGS system from January 2003 to March 2013 were retrospectively analyzed. We defined 2 groups: group I with an IGS system based on a preoperative CT scan; group II relied on an intraoperative CT scan. Screw accuracy was assessed with a postoperative CT scan control. Radiation dosage for patients was defined by using the technical parameters and dose report data. Statistical analysis was performed using the Fisher exact test with a significance of 5% (P value < .05).

RESULTS: Two thousand twenty patients and 11 144 screws were analyzed. Group I had 794 patients (4246 screws); the accuracy was 96.1%. Group II had 1226 patients (6898 screws) treated, with 98.5% accuracy (P = .001). The radiation dose analysis showed better results in group II, with significant reduction of the effective dose to the patient.

CONCLUSION: The IGS based on an intraoperative CT scan grants excellent results, eliminating the rate of reoperation for misplaced instrumentations (screws, plate, and cage) or for inadequate bone decompression. However, this technology cannot replace the surgical skills, experience, and knowledge necessary for spine surgery.

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A clinical prediction model to assess surgical outcome in patients with cervical spondylotic myelopathy

A clinical prediction model to assess surgical outcome in patients with cervical spondylotic myelopathy

The Spine Journal 15 (2015) 388–397

Clinical prediction rules are valuable tools in a surgical setting but should not be used to guide clinical practice until validated in other populations.

PURPOSE: The objective of this study was to validate a clinical prediction rule developed to determine surgical outcome in patients with cervical spondylotic myelopathy (CSM). The study will also identify key clinical predictors of outcome at a global level.

STUDY DESIGN/SETTING: This is a prospective multicenter cohort study.

PATIENT SAMPLE: Two-hundred seventy-eight and 479 surgical CSM patients enrolled in the AOSpine CSM—North American (CSM-NA) and CSM—International (CSM-I) studies, respectively.

OUTCOME MEASURES: The outcome measure was a Modified Japanese Orthopedic Association (mJOA) Scale.

METHODS: A clinical prediction model was built using data from 272 patients enrolled in the CSM-NA study. Bootstrapping was used for internal validation. The original model was externally validated using data on 471 patients participating in the CSM-I study. The predictive performance of the model was evaluated, including its discrimination, measured by area under the receiver operating curve (AUC), and calibration, assessed by calibration slope, observed: expected ratios, and Hosmer-Lemeshow goodness-of-fit test.

RESULTS: The modified original model consisted of six covariates: age (odds ratio [OR], 0.96), duration of symptoms (0.76), baseline severity score (1.21), psychiatric comorbidities (0.44), impairment of gait (2.48), and smoking status (0.50). The AUC for the original model was 0.77 (95% confidence interval [CI]: 0.71, 0.82) and across the bootstrap replicates was 0.77 (95% CI: 0.76, 0.77), reflecting good discrimination and internal validity. The model tested on the CSM-I dataset yielded an AUC of 0.74 (95% CI: 0.69, 0.79), a calibration slope of 0.75, and an insignificant Hosmer-Lemeshow test. The ORs generated for baseline mJOA (OR, 1.26), impairment of gait (2.67), age (0.97), and smoking (0.55) were very similar to the original values of 1.28, 2.39, and 0.97, respectively. Duration of symptoms (OR, 0.94) had a significantly different odds ratio than in the original model, but the direction of its relationship with outcome was the same. Psychiatric comorbidities was not a significant predictor at an international level, likely because of underreporting: only six patients outside of North American centers were diagnosed with depression or bipolar.

CONCLUSIONS: The parameter estimates generated from the original analysis were internally valid. The original model was also externally valid. The most significant global predictors of surgical outcome were baseline myelopathy severity, age, smoking status and impaired gait.

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Management of C1–2 traumatic fractures using an intraoperative 3D imaging–based navigation system

Management of C1–2 traumatic fractures using an intraoperative 3D imaging–based navigation system

J Neurosurg Spine 22:128–133, 2015

Fractures of C-1 and C-2 are complex and surgical management may be difficult and challenging due to the anatomical relationship between the vertebrae and neurovascular structures. The aim of this study was to evaluate the role, reliability, and accuracy of cervical fixation using the O-arm intraoperative 3D image–based navigation system.

Methods The authors evaluated patients who underwent a navigation system–based surgery for stabilization of a fracture of C-1 and/or C-2 from August 2011 to August 2013. All of the fixation screws were intraoperatively checked and their position was graded.

Results The patient population comprised 17 patients whose median age was 47.6 years. The surgical procedures were as follows: anterior dens screw fixation in 2 cases, transarticular fixation of C-1 and C-2 in 1 case, fixation using the Harms technique in 12 cases, and occipitocervical fixation in 2 cases. A total of 67 screws were placed. The control intraoperative CT scan revealed 62 screws (92.6%) correctly placed, 4 (5.9%) with a minor cortical violation (< 2 mm), and only 1 screw (1.5%) that was judged to be incorrectly placed and that was immediately corrected. No vascular injury of the vertebral artery was observed either during exposition or during screw placement. No implant failure was observed.

Conclusions The use of a navigation system based on an intraoperative CT allows a real-time visualization of the vertebrae, reducing the risks of screw misplacement and consequent complications.

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Is atlantoaxial instability the cause of Chiari malformation? Outcome analysis of 65 patients treated by atlantoaxial fixation

Is atlantoaxial instability the cause of Chiari malformation?

J Neurosurg Spine 22:116–127, 2015

Understanding that atlantoaxial instability is the cause of Chiari malformation (CM), the author treated 65 patients using atlantoaxial stabilization. The results are analyzed.

Methods Cases of CM treated using atlantoaxial fixation during the period from January 2010 to November 2013 were reviewed and analyzed. Surgery was aimed at segmental arthrodesis.

Results The author treated 65 patients with CM in the defined study period. Fifty-five patients had associated syringomyelia. Forty-six patients had associated basilar invagination. Thirty-seven patients had both basilar invagination and syringomyelia. Three patients had been treated earlier using foramen magnum decompression and duraplasty. According to the extent of their functional capabilities, patients were divided into 5 clinical grades. On the basis of the type of facetal alignment and atlantoaxial instability, the patients were divided into 3 groups. Type I dislocation (17 patients) was anterior atlantoaxial instability wherein the facet of the atlas was dislocated anterior to the facet of the axis. Type II dislocation (31 patients) was posterior atlantoaxial instability wherein the facet of the atlas was dislocated posterior to the facet of the axis. Type III dislocation (17 patients) was the absence of demonstrable facetal malalignment and was labeled as “central” atlantoaxial dislocation. In 18 patients, dynamic images showed vertical, mobile and at-least partially reducible atlantoaxial dislocation. All patients were treated with atlantoaxial plate and screw fixation using techniques described in 1994 and 2004. Foramen magnum decompression or syrinx manipulation was not performed in any patient. Occipital bone and subaxial spinal elements were not included in the fixation construct. One patient died, and death occurred in the immediate postoperative phase and was related to a vertebral artery injury incurred during the operation. One patient had persistent symptoms. In the rest of the patients there was gratifying clinical improvement. More remarkably, in 7 patients, the symptoms of lower cranial nerve paresis improved. No patient worsened in their neurological function after surgery. Reductions in the size of the syrinx and regression of the CM were observed in 6 of 11 cases in which postoperative MRI was possible. During the follow-up period, there was no delayed worsening of neurological function or symptoms in any patient. Sixty-three patients improved after surgery, and the improvement was sustained during the average follow-up period of 18 months.

Conclusions On the basis of outcomes in this study, it appears that the pathogenesis of CM with or without associated basilar invagination and/or syringomyelia is primarily related to atlantoaxial instability. The data suggest that the surgical treatment in these cases should be directed toward atlantoaxial stabilization and segmental arthrodesis. Except in cases in which there is assimilation of the atlas, inclusion of the occipital bone is neither indicated nor provides optimum stability. Foramen magnum decompression is not necessary and may be counter-effective in the long run.

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Atlantoaxial Instability of Inflammatory Origin in Adults

Atlantoaxial Instability of Inflammatory Origin in Adults

Neurosurgery 76:E226–E232, 2015

Acquired atlantoaxial instability of inflammatory origin (Grisel syndrome) is a rare condition. It usually occurs in children with benign upper airway problems and responds well to immobilization, rarely requiring C1-2 arthrodesis. Our recent experience with 2 adult cases suggests this may not be true in an older subpopulation.

CLINICAL PRESENTATION: A 71-year-old man developed C1-2 instability in the setting of culture-negative endocarditis. Initial immobilization was attempted for 8 weeks but new imaging revealed progressive destruction of the odontoid and worsening instability. Symptoms resolved after C1-4 arthrodesis. A 35-year-old woman developed C1-2 instability after a molar extraction and otitis media. Despite 12 weeks of immobilization and antibiotics, symptoms persisted and the atlantodental interval increased. She was successfully treated with a C1-2 arthrodesis.

CONCLUSION: A literature review revealed 13 reports (14 cases) of inflammatory atlantoaxial instability in patients aged 18 and older since 1830. Including the 2 cases reported here, 11 cases underwent initial nonoperative treatment with durable satisfactory results in only 2 of them (18.2%). Aspiration of the C1-2 phlegmon was diagnostic in only 4 of these 16 cases. Destruction of the odontoid was seen in a minority of cases (5/16, 31.3%). In this first review of the topic since the introduction of screwbased C1-2 fixation, it is suggested that nonoperative treatment is futile for inflammatory atlantoaxial instability in adults and strong consideration should be given to C1-2 arthrodesis. This procedure can reliably produce good outcomes with minimal morbidity.

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Anterior cervical discectomy versus corpectomy for multilevel cervical spondylotic myelopathy: a meta-analysis

Anterior cervical discectomy versus corpectomy for multilevel cervical spondylotic myelopathy

Eur Spine J (2015) 24:31–39

This is a meta-analysis to compare the results between anterior cervical discectomy fusion (ACDF) and anterior cervical corpectomy fusion (ACCF) for the patients with multilevel cervical spondylotic myelopathy (MCSM).

Methods Systematic review and meta-analysis of cohort studies between ACDF with plate fixation and ACCF with plate fixation for the treatment of MCSM. An extensive search of literature was performed in PubMed, Mediline, Embase and the Cochrane library. The following outcome measures were extracted: JOA scores, fusion rate, cervical lordosis (C2–7), complications, blood loss and operation time. Data analysis was conducted with RevMan 5.0.

Results Four cohorts (six studies) involving 258 patients were included in this study. The pooled analysis showed that there was no significant difference in the postoperative JOA score [WMD = -0.14 (-1.37, 1.10), P = 0.83], fusion rate [OR = 0.84 (0.15, 4.86), P = 0.85] between two group. However, there was significant difference in the cervical lordosis [WMD = 3.38 (2.52, 4.23), P<0.00001], surgical complication rate and instrument related complication rate (P = 0.01, 0.005 respectively), blood loss [WMD = -52.53 (-73.53, -31.52), P<0.00001], and operation time [WMD = -14.10 (-20.27, -7.93), P<0.00001].

Conclusions As compared with ACCF with plate fixation, ACDF with plate fixation showed no significant differences in terms of postoperative JOA score, fusion rate, but better improved cervical lordosis, lower complication and smaller surgical trauma. As the limitations of small sample and short follow-up in this study, it still could not be identified whether ACDF with plate fixation is more effective and safer than ACCF with plate fixation.

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The immediately failed lumbar disc surgery

Micro-Lumbar-Discectomy-surgery4

Neurosurg Rev (2015) 38:191–195

Studies on immediate failed back surgery syndrome (iFBSS) following lumbar microdiscectomy are rare. Our aim is to describe the incidence and the causes of these immediate failures to define the value of radiological imaging for identification of the underlying pathology and to propose a management algorithm.

We defined iFBSS as persistence, deterioration or recurrence (during hospital stay) of radicular pain and/or sensorimotor deficits and/or sphincter dysfunction after microdiscectomy, which was uneventful from the surgeon’s perspective.

The medical records of 1546 patients undergoing discectomy for mediolateral lumbar disc herniations were screened for iFBSS. The pre- and postoperative imaging, surgical records, therapy and outcome of patients with iFBSS were reviewed. Forty-four of 1546 patients (2.8 %) with iFBSS were identified. All patients underwent reoperation. Overseen disc material/re-herniation (n=22), epidural hematoma (n=6), inadequate decompression of accompanying recessal stenosis (n=2) and dural tear with fascicle herniation (n=1) were found to be causative. In 13 patients, who revealed no clear pathology intraoperatively, we diagnosed a battered root syndrome (nerve root swelling due to excessive surgical manipulation). The correct diagnosis could be established by neuroradiological imaging in 25 of 43 radiologically investigated patients (57 %). In our study, the radiological workup was of limited value for the correct differentiation of the various aetiologies of iFBSS.

Therefore, the authors believe that the treatment strategy should strongly rely on the clinical presentation. To avoid unnecessary surgery in cases of battered root syndrome, we propose to proceed to reoperation only in patients with new or persistent radiculopathy despite adequate antiedematous medical therapy.

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Outcomes of Anterior Lumbar Interbody Fusion Surgery Based on Indication: A Prospective Study

Outcomes of Anterior Lumbar Interbody Fusion Surgery Based on Indication- A Prospective Study

Neurosurgery 76:7–24, 2015

There is limited information on clinical outcomes after anterior lumbar interbody fusion (ALIF) based on the indications for surgery.

OBJECTIVE: To compare the clinical and radiological outcomes of ALIF for each surgical indication.

METHODS: This prospective clinical study included 125 patients who underwent ALIF over a 2-year period. The patients were evaluated preoperatively and postoperatively. Outcome measures included the Short Form-12, Oswestry Disability Index, Visual Analog Scale, and Patient Satisfaction Index.

RESULTS: After a mean follow-up of 20 months, the clinical condition of the patients was significantly better than their preoperative status across all indications. A total of 108 patients had a Patient Satisfaction Index score of 1 or 2, indicating a successful clinical outcome in 86%. Patients with degenerative disk disease (with and without radiculopathy), spondylolisthesis, and scoliosis had the best clinical response to ALIF, with statistically significant improvement in the Short Form-12, Oswestry Disability Index, and Visual Analog Scale. Failed posterior fusion and adjacent segment disease showed statistically significant improvement in all of these clinical outcome scores, although the mean changes in the Short Form-12 Mental Component Summary, Oswestry Disability Index, and Visual Analog Scale (back pain) were lower. The overall radiological fusion rate was 94.4%. Superior radiological outcomes (fusion .90%) were observed in patients with degenerative disk disease (with and without radiculopathy), spondylolisthesis, and failed posterior fusion, whereas in adjacent segment disease, it was 80%.

CONCLUSION: ALIF is an effective treatment for degenerative disk disease (with and without radiculopathy) and spondylolisthesis. Although results were promising for scoliosis, failed posterior fusion, and adjacent segment disease, further studies are necessary to establish the effectiveness of ALIF in these conditions.

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Instrumentation of the Posterior Thoracolumbar Spine: From Wires to Pedicle Screws

Instrumentation of the Posterior Thoracolumbar Spine- From Wires to Pedicle Screws

Operative Neurosurgery 10:497–505, 2014

Over the past 120 years, spinal stabilization has advanced immensely. An updated review highlighting these advancements has not been performed in the past 20 years.

The objective of this report is to provide a historical assessment of the decades outlining various key innovators, their techniques, and instrumentation.

It is important to provide new generations of surgeons and students with historical evidence of the value of developing new techniques and instrumentation to improve patient care and outcomes.

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Ultrasonic Total Uncinectomy

Ultrasonic Total Uncinectomy

Operative Neurosurgery 10:535–541, 2014

In standard anterior cervical diskectomy, complete resection of the uncinate process is not commonly attempted because of the risk of injury to the vertebral artery. This may result in incomplete decompression of the nerve root when there is severe osseous foraminal stenosis.

OBJECTIVE: To demonstrate the feasibility of total uncinectomy with an ultrasonic bone dissector in patients with concomitant central and foraminal stenosis requiring anterior decompression and fusion.

METHODS: A case series of patients with cervical radiculopathy or myeloradiculopathy who underwent single-level or multilevel ultrasonic total uncinectomy (UTU) in combination with anterior cervical diskectomy and fusion is presented. The uncinate process was amputated along its base with an ultrasonic bone dissector and removed en bloc to expose the cervical root and the vertebral artery. Data gathered in accordance with routine practice were analyzed retrospectively.

RESULTS: Forty-four uncinate processes were resected in 38 patients. No UTU procedures were aborted because of technical difficulties, and no vertebral artery or nerve root injury occurred. Mean follow-up was 28 weeks (range, 14-37 weeks). Mean Neck Disability Index and Visual Analog Scale scores for neck and arm pain improved from 42%, 4.9%, and 6.8% to 23%, 2.6%, and 2.1%, respectively. Postoperative computed tomography and oblique radiographs revealed complete decompression of the neural foramen after UTU.

CONCLUSION: UTU is a safe and effective technique for complete decompression of cervical nerve roots when the coexistence of central and foraminal pathology dictates an anterior approach. The surgical technique is described in detail.

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Joint Indexes for the Craniovertebral Junction

New Indexes for the Craniovertebral Junction

Neurosurgery 10:621–630, 2014

Joint-distraction and intra-operative manipulation surgeries to correct basilar invagination (BI) and atlantoaxial dislocation (AAD) are becoming standard procedures. However, current data are unable to aid in the understanding of normal and abnormal morphology of the C1/C2 joints.

OBJECTIVE: To study various aspects of C1/C2 joint morphology to create normative and patient data on joint abnormalities that could provide the surgeon with objective data for surgical planning and approach.

METHODS: Seventy patients (age, 15-45 years) were compared with an equal number of age- and sex-matched control subjects (age, 21.9±8.2 years) with irreducible BI and AAD from a developmental origin (May 2010-July 2013). Joint anatomy was studied with the use of thin-slice computed tomography scans. The joint parameters studied included sagittal joint inclination, craniocervical tilt, coronal joint inclination, surface area, joint overlap index, and joint reciprocity. The severity of BI and the severity of AAD were compared.

RESULTS: Sagittal joint inclination and craniocervical tilt significantly correlated with both BI and AAD (P , .01). Coronal joint inclination correlated with BI (P = .2). The mean sagittal joint inclination value in control subjects was 87.15±5.65 and in patients with BI and AAD was 127.1±22.05. The mean craniocervical tilt value in controls was 60.2±9.2 and in patients with BI and AAD was 84.0±15.1. The mean coronal joint inclination value in control subjects was 110.3±4.23 and in patients with BI and AAD was 121.15±14.6.

CONCLUSION: This study has demonstrated for the first time the important role of joint orientation and its correlation with the severity of BI and AAD and has described new joint indexes.

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Minimally invasive lateral fusion for adjacent disease

Minimally invasive lateral interbody fusion for the treatment of rostral adjacent-segment lumbar degenerative stenosis without supplemental pedicle screw fixation

J Neurosurg Spine 21:861–866, 2014

Adjacent-segment degeneration and stenosis are common in patients who have undergone previous lumbar fusion. Treatment typically involves a revision posterior approach, which requires management of postoperative scar tissue and previously implanted instrumentation. A minimally invasive lateral approach allows the surgeon to potentially reduce the risk of these hazards. The technique relies on indirect decompression to treat central and foraminal stenosis and placement of a graft with a large surface area to promote robust fusion and stability in concert with the surrounding tensioned ligaments. The goal in this study was to determine if lateral interbody fusion without supplemental pedicle screws is effective in treating adjacent-segment disease.

Methods. For a 30-month study period at two institutions, the authors obtained all cases of lumbar fusion with new back and leg pain due to adjacent-segment stenosis and spondylosis failing conservative measures. All patients had undergone minimally invasive lateral interbody fusion from the side of greater leg pain without supplemental pedicle screw fixation. Patients were excluded from the study if they had undergone surgery for a nondegenerative etiology such as infection or trauma. They were also excluded if the intervention involved supplemental posterior instrumented fusion with transpedicular screws. Postoperative metrics included numeric pain scale (NPS) scores for leg and back pain. All patients underwent dynamic radiographs and CT scanning to assess stability and fusion after surgery.

Results. During the 30-month study period, 21 patients (43% female) were successfully treated using minimally invasive lateral interbody fusion without the need for subsequent posterior transpedicular fixation. The mean patient age was 61 years (range 37–87 years). Four patients had two adjacent levels fused, while the remainder had single-level surgery. All patients underwent surgery without conversion to a traditional open technique, and recombinant human bone morphogenetic protein–2 was used in the interbody space in all cases. The mean follow-up was 23.6 months. The mean operative time was 86 minutes, and the mean blood loss was 93 ml. There were no major intraoperative complications, but one patient underwent subsequent direct decompression in a delayed fashion. The leg pain NPS score improved from a mean of 6.3 to 1.9 (p < 0.01), and the back pain NPS score improved from a mean of 7.5 to 2.9 (p < 0.01). Intervertebral settling averaged 1.7 mm. All patients had bridging bone on CT scanning at the last follow-up, indicating solid bony fusion.

Conclusions. Adjacent-segment stenosis and spondylosis can be treated with a number of different operative techniques. Lateral interbody fusion provides an attractive alternative with reduced blood loss and complications, as there is no need to re-explore a previous laminectomy site. In this limited series a minimally invasive lateral approach provided high fusion rates when performed with osteobiological adjuvants.

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Effect of lordosis angle change after lumbar/lumbosacral fusion on sacrum angular displacement

Sacrum angular displacement

Eur Spine J (2014) 23:2369–2374

To assess and characterize the sacrum angular displacements in response to lumbar lordosis after lumbar/ lumbosacral fusion.

Methods A finite element model of the lower lumbar spine-pelvis was established and used to simulate the posterior fusion at L3–L5 and L4–S1. The lordosis angle in the fusion segments was set to five different conditions with respect to the intact model: 10 less than intact, 5 less than intact, same as intact, 5 more than intact, and 10 more than intact. Variations of the sacrum angular displacements with lordosis changes were analyzed under loading setting of axial compression, flexion, extension, lateral bending, and axial rotation.

Results Compared with the intact lordosis, both increased and decreased lumbar lordosis angles caused the sacrum angular displacements to be increased. The lordosis angle increased by 10º induced the most substantial increase in sacrum angular displacements. In addition, the sacrum angular displacements of the L4–S1 fusion model at different lordosis angles were higher than those of the L3–L5 fusion model.

Conclusion The sacrum angular displacements occur as a result of the fusion surgery (L4–S1) and the changes in lumbar lordosis.

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The direct anterior approach to the thoracolumbar junction

The direct anterior approach to the thoracolumbar junction

Eur Spine J (2014) 23:2265–2271

The thoracolumbar junction (TJ) is traditionally exposed by lateral or posterior approaches. This usually requires splitting of the diaphragm, or extensile removal of the posterior elements. A circumferential exposure (i.e. simultaneous anterior and bilateral exposure) of the vertebral body is not possible. Direct anterior access would allow circumferential exposure of the vertebral body, with adjacent disc levels, and would avoid splitting the diaphragm or extensive removal of the posterior bony structures.

Materials and methods Twelve Thiel cadavers (8 f/4 m) were dissected to access T12 or L1 via a midline laparotomy. Supra- and infragastric laparatomy techniques were investigated. Six cadavers were used to reach T12 through the lesser omentum, six to reach L1 through the greater omentum.

Results T12 after bluntly dissecting the lesser omentum, the lesser gastric curvature and the caudate lobe of the liver were utilised as landmarks. A small retroperitoneal incision was performed to mobilise the aorta allowing exposure of the T12 vertebra and its adjacent discs. Discectomy, corpectomy and insertion of an anterior column support were possible. The L1 level can be reached through the greater omentum by mobilising the pancreas as a single retroperitoneal structure, leaving the aorta and celiac trunk as landmarks. Retraction of the great vessels is necessary to expose L1 with its adjacent discs. Implantation of an anterior column support was possible utilising this approach.

Conclusion Direct anterior access to the TJ is feasible in a reproducible manner. This approach would avoid splitting the diaphragm, or dissection of the erector spinae muscles, and is likely to be less invasive than standard lateral or posterior approaches. This technique may offer a significant time reduction to surgery, especially in exposing the spine. Anterior column support can easily be performed, offering a better avoidance of kyphotic deformities.

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Management of lumbar spinal stenosis: a survey among Dutch spine surgeons

lumbar stenosis

Acta Neurochir (2014) 156:2139–2145

Various surgical and non-surgical treatments for lumbar spinal stenosis (LSS) are widely adopted in clinical practice, but high quality randomised controlled trials to support these are often lacking, especially in terms of their relative benefit and risk compared with other treatment options. Therefore, an evaluation of agreement among clinicians regarding the indications and the choice for particular treatments seems appropriate.

Methods One hundred and six Dutch neurosurgeons and orthopaedic spine surgeons completed a questionnaire, which evaluated treatment options for LSS and expectations regarding the effectiveness of surgical and non-surgical treatments.

Results Responders accounted for 6,971 decompression operations and 831 spinal fusion procedures for LSS annually. Typical neurogenic claudication, severe pain/disability, and a pronounced constriction of the spinal canal were considered the most important indications for surgical treatment by the majority of responders. Non-surgical treatment was generally regarded as ineffective and believed to be less effective than surgical treatment. Interlaminar decompression was the preferred technique by 68 % of neurosurgeons and 52 % orthopaedic surgeons for the treatment of LSS. Concomitant fusion was applied in 12% of all surgery for LSS. Most surgeons considered spondylolisthesis as an indication and spinal instability as a definite indication for additional fusion.

Conclusions The current survey demonstrates a wide variety of preferred treatments of symptomatic LSS by Dutch spine surgeons. To minimise variety, national and international protocols based on high-quality randomised controlled trials and systematic reviews are necessary to give surgeons more tools to support everyday decision-making.

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Major vascular injury following lateral transpsoas approach

Major vascular injury following lateral transpsoas approach

J Neurosurg Spine 21:794–798, 2014

Extreme lateral interbody fusion (XLIF) has gained popularity among spine surgeons for treating multiple conditions of the lumbar spine. In contrast to the anterior lumbar interbody fusion (ALIF) approach, the minimally invasive XLIF approach affords wide access to the lumbar disc space without an access surgeon and causes minimal tissue disruption. The XLIF approach offers many advantages over other lumbar spine approaches, with a reportedly low complication profile.

The authors describe the first fatality reported in the literature following an XLIF approach. They describe the case of a 50-year-old woman who suffered a fatal intraoperative injury to the great vessels during a lateral transpsoas approach to the L4–5 disc space.

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Electrophysiologic deterioration in surgery for thoracic disc herniation

Th. Disc Herniation

Eur Spine J (2014) 23:2279–2290

Severe thoracic disc herniation leads to increased pressure in adjacent neural structures, which in turn can require an increase in mean arterial pressure (MAP) to maintain adequate spinal cord perfusion.We report a case series of three patients with severe thoracic disc herniation that experienced deteriorations in motorevoked potentials (MEPs) and somatosensory evoked potentials (SSEPs) following induction of general anesthesia, but prior to decompression of the neural elements.

Methods In-depth chart reviews were completed for each patient from their initial presentation to long-term postoperative course. Careful attention was taken with regards to MAP at induction of each operative case.

Results The origin of the decreased signals in all patients was thought to relate to inadequate cord perfusion pressures. Two of the patients recovered pre-operative neurologic function while the third was left with mild postoperative paraparesis. Mean arterial pressures at time of deterioration were noted to be 58, 80, and 60 mmHg. These measurements represented MAPs approximately 65, 92, and 60 % those of baseline values, respectively.

Conclusion Based on these experiences, the authors’ institution has adopted new guidelines in the setting of thoracic disc herniations that includes pre-operative optimization of volume status, placement of an awake arterial line prior to induction of anesthesia, use of MEP and SSEP electrophysiologic monitoring, careful selection of anesthetic, and aggressive maintenance of MAPs >110 % of preoperative values at all times prior to decompression of the spinal cord.

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Surgery of Intradural Extramedullary Tumors: Retrospective Analysis of 107 Cases

Intradural extramedullary tumors

Neurosurgery 75:509–514, 2014

Intradural extramedullary tumors (IDEMTs) are uncommon lesions that cause pain and neurological deficits.

OBJECTIVE: To evaluate the effects of surgery for IDEMTs.

METHODS: This cohort study recruited all patients operated on for IDEMTs at the Department of Neurology and Psychiatry of Sapienza University of Rome from January 2003 to January 2013. The analysis was conducted on clinical records evaluation over a 1-year follow-up. The Graphic Rating Scale was used to assess pain. Neurological deficits were detected through neurological examination. Quality of life was evaluated with the EuroQol (EQ-5D). Statistical interpretation of the data was performed with SPSS version 19 software.

RESULTS: One hundred seven patients were recruited. Three were lost to follow-up. Patients reported lower level of pain 1 year after surgery (before surgery, 6.05; after surgery, 3.65). Mean comparison showed a significant decrease of 22.400 (P , .001). Ninety-two patients (88.5%) were neurologically asymptomatic 1 year after surgery. Only 12 patients (11.5%) presented with a deficit, with a global decrease of 39% (x2 = 27.6; P, .005). The quality of life in patients was middle to high (mean rating of EQ-5D visual analog score, 61.78%). The lowest levels of quality of life were found in patients with sphincter dysfunctions (mean, 33.4).

CONCLUSION: Surgery for IDEMTs has a good outcome. Patients reported lower levels of pain and a drastic reduction in neurological symptoms 1 year after surgery. The quality of life is middle to high. It is influenced mainly by the neurological outcome.

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Aneurysmal bone cysts of the spine: treatment options and considerations

ABC

J Neurooncol (2014) 120:171–178

Aneurysmal bone cysts (ABCs) are benign bone lesions with annual incidences ranging from 1.4 to 3.2 cases per million people. Approximately, 10–30 % of ABCs are found in the spine. Such lesions are traditionally treated with curettage or other intralesional techniques.

Because ABCs can be locally aggressive, intralesional resection can be incomplete and result in recurrence. This has led to increased use of novel techniques, including selective arterial embolization (SAE).

This study aims to: (1) compare outcomes based on extent of surgical resection, and (2) compare the efficacy of SAE versus surgical resection.

Clinical data pertaining to 71 cases of spinal ABCs were ambispectively collected from nine institutions in Europe, North America, and Australia. Twenty-two spinal ABCs were treated with surgery, 32 received preoperative embolization and surgery, and 17 were treated with SAE.

Most tumors were classified as Enneking stage 2 (n = 29, 41 %) and stage 3 (n = 29, 41 %). Local recurrence and survival were investigated and a significant difference was not observed between treatment groups. However, all three local recurrences occurred following surgical resection. Surgical resection was further categorized based on Enneking appropriateness. Recurrences only occurred following intralesional Enneking inappropriate (EI) resections (P = 0.10), a classification that characterized 47 % of all surgical resections. Furthermore, 56 % of intralesional resections were EI, compared to only 10 % of en bloc resections (P = 0.01). Although SAE treatment did not result in any local recurrences, 35 % involved more than five embolization procedures.

Spinal ABCs can be effectively treated with intralesional resection, en bloc resection, or SAE. Preoperative embolization should be considered before intralesional resection to limit intraoperative bleeding. Treatment plans must be guided by lesion characteristics and clinical presentation.

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