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Clinical Spine Surgery - Current Issue

Clinical Spine Surgery - Current Issue
  1. Surgery for Chronic Traumatic Atlantoaxial Dislocation Associated With Myelopathy
    imageStudy Design: A retrospective study. Objective: To evaluate the outcomes of myelopathy caused by atlantoaxial dislocation (AAD). Summary of Background Data: No reports to date have accurately evaluated the results of surgery for delayed myelopathy for patients with chronic AAD. Thus, the appropriate surgical time and methods of decompression and fusion remain a hot debate. Materials and Methods: In our study, 18 patients underwent decompression, fixation, and fusion. Demographic data, operation time, blood loss, and complications were evaluated. The Japanese Orthopedic Association Scale, severity of disability and visual analogue scale were evaluated. The fusion rate, space available for the cord, instability index, cord compression index, and cord decompression rate were also assessed. Results: The average time of operation was 248±50 minutes, and blood loss was 350±200 mL. Five patients in grade I maintained their neurological status, and the others had improved neurological status. With average follow-up time of 15.3±9.6 months, the Japanese Orthopedic Association score improved, the visual analogue scale score decreased, the space available for the cord improved, and the instability index and cord compression index decreased. Cord decompression rate was 65.9%. Fusion rate reached 83%. Conclusions: There is a high risk of delayed myelopathy for patients with AAD who do not undergo timely surgical treatment. There is no need for complete reduction for treatment of chronic AAD. Whether it can be reduced or not, sufficient decompression and solid fusion for AAD are required. Both C1–C2 fusion for reducible dislocation and occipital-cervical fusion for irreducible dislocation have satisfactory outcomes.



  2. Development of a Remodeled Caspar Retractor and Its Application in the Measurement of Distractive Resistance in an In Vitro Anterior Cervical Distraction Model
    imageStudy Design: In vitro biomechanical study of the cervical intervertebral distraction using a remodeled Caspar retractor. Objective: To investigate the torques required for distraction to different heights in an in vitro C3–C4 anterior cervical distraction model using a remodeled Caspar retractor, focusing on the influence of the intervertebral disk, posterior longitudinal ligament (PLL), and ligamentum flavum (LF). Summary of Background Data: No previous studies have reported on the torques required for distraction to various heights or the factors resisting distraction in anterior cervical discectomy and fusion. Methods: Anterior cervical distractions at C3–C4 was performed in 6 cadaveric specimens using a remodeled Caspar retractor, under 4 conditions: A, before disk removal; B, after disk removal; C, after disk and PLL removal; and D, after disk and PLL removal and cutting of the LF. Distraction was performed for 5 teeth, and distractive torque of each tooth was recorded. Results: The torque increased with distraction height under all conditions. There was a sudden increase in torque at the fourth tooth under conditions B and C, but not D. Under condition A, distraction to the third tooth required 84.8±13.3 cN m. Under conditions B and C, distraction to the third tooth required <13 cN m, and further distraction required dramatically increased torque. Under condition D, no marked increase in torque was recorded. Conclusions: Distraction of the intervertebral space was much easier after disk removal. An intact LF caused a sudden marked increase in the force required for distraction, possibly indicating the point at which the LF was fully stretched. This increase in resistance may help to determine the optimal distraction height to avoid excessive stress to the endplate spacer. The remodeled Caspar retractor in the present study may provide a feasible and convenient method for intraoperative measurement of distractive resistance.



  3. Sports-related Concussion in Children and Adolescents
    imageConcussions are becoming increasingly important to manage properly as sports participation continues to rise. Repeated injuries occurring before the brain has had a chance to recover from an initial insult are particularly dangerous and must be prevented. Although much national media attention has been devoted to concussions in professional sports, it is important to appreciate that athletes in any age group, children and adolescents in particular, are at risk of sports-related concussion. It is crucial to remove an athlete from play any time concussion is suspected. Once removed from play, recovery then begins with a period of cognitive and physical rest, followed by a gradual return to cognitive and athletic activities as symptoms resolve. Children and adolescents pose a unique challenge to the clinician managing their recovery, as the physical and cognitive rest periods required often involve time away from school and sports, which can be academically detrimental and socially isolating. Recently developed sideline assessment tools have greatly aided the urgent sideline assessment of an athlete suspected of having a concussion. In this article, a brief review of current guidelines is presented in tandem with the authors’ preferred treatment of concussion.



  4. Outcome of Bilateral C1 Laminar Hooks Combined With C2 Pedicle Screw Fixation for the Treatment of C1–C2 Instability: A Report of 18 Cases From a Single Chinese Center
    imageStudy Design: A retrospective technical report. Objective: To assess the effect of bilateral C1 laminar hooks combined with C2 pedicle screw fixation for the treatment of C1–C2 instability. Summary of Background Data: Various posterior atlantoaxial fixations for C1–C2 instability have been developed. However, due to anatomic anomalies of the vertebral artery, the smallness of the pedicle, trajectories of broken screws, or a lack of surgical experience, a simple atlantoaxial fixation technique with good safety and effectiveness is urgently needed. Materials and Methods: From January 2007 to September 2012, 18 patients with C1–C2 instability who underwent posterior bilateral C1 laminar hooks combined with C2 pedicle screw fixation were evaluated. Six patients had acute odontoid fractures (Anderson IIc type), 8 patients had odontoid pseudarthrosis, 3 had os odontoideum, and 1 had a traumatic rupture of the transverse ligament. The mean age at the time of surgery was 34.1 years. The clinical and radiographic analyses were performed before and after the operation and at follow-up. Results: The follow-up period was 12–78 months (with an average follow-up period of 25.6 mo). All patients were relieved of pain and their neurological symptoms were substantially improved. The postoperative JOA score improved significantly (t=−7.234, P<0.001). No neurological or vascular complications occurred in these cases. The device was placed well and had not loosened or broken and plain radiographs revealed bony fusion in 17 patients. One patient had C1 posterior arch fracture 3 weeks postoperatively and she was followed up for 18 months without revision surgery. Conclusions: When appropriate patients were selected, bilateral C1 laminar hooks combined with C2 pedicle screw fixation can be an alternative method to treat C1–C2 instability effectively with a relatively simple procedure. Preoperative planning and evaluation were crucial for the solid atlantoaxial fusion.



  5. Facet Preserving Technique by En Bloc Flavectomy in Microscopic Posterior Decompression Surgery for Lumbar Spinal Stenosis: Semicircumferential Decompression (SCD)
    imagePosterior decompression surgery which enlarges the spinal canal in cases with lumbar spinal stenosis is the most fundamental technique in spine surgery, but controversy still remains for the exact technique. Because nerve roots run under the ventral side on the superior articular process (SAP), achieving both facet joint preservation and nerve root decompression is problematic. In conventional laminotomies or laminectomies, medial facetectomies are performed to decompress the nerve root, but it is ideal to preserve the facet joints completely for preserving joint stability. We handle this problem with an original decompression technique, called “semicircumferential decompression.” The main features of this procedure are an en bloc flavectomy and total preservation of facet joints. The procedure is performed under the microscope with a midline approach. The flavum is detached from the ventral surface of the SAP using a currete without disturbing the SAP. The facet joints are preserved completely. The advantage of an en bloc flavectomy is that we can remove the flavum attachment to the ventral surface of SAP totally without a medial facetectomy. Since 1991, we have performed this technique in more than 5000 cases. In this paper, we will explain the tips, pitfalls, and advantages of this technique.


  6. Metabolic Imaging Using Proton Magnetic Spectroscopy as a Predictor of Outcome After Surgery for Cervical Spondylotic Myelopathy
    imageStudy Design: A single-center magnetic resonance spectroscopy (MRS) imaging and surgical outcome study involving 16 patients with cervical spondylotic myelopathy (CSM). Objective: In the present study, we assess the utility of MRS to quantify metabolic changes within the spinal cord and predict surgical outcome in CSM patients. Summary of Background Data: MRS is an advanced spinal imaging modality that can provide pertinent metabolic and biochemical information regarding spinal cord function. Previous studies have demonstrated significant abnormalities in specific cellular metabolite concentrations in CSM patients. Methods: Sixteen patients with CSM were evaluated. Single voxel MRS was performed in the cervical cord. N-acetyl-aspartate (NAA) and choline metabolite concentration ratios with respect to creatine were quantified, as well as the presence or absence of a lactate peak. The modified Japanese Orthopaedic Association (mJOA) scale was used as the functional assessment measure. Correlation of MRS metabolites with change in mJOA score was performed. Results: The mean follow-up time was 19 months. There was a statistically significant improvement between mean preoperative and postoperative mJOA score after surgery (P<0.0001). The NAA/Cr ratio demonstrated a significant relationship to the change in mJOA score after surgery (P=0.0479; R2=0.2513). The Cho/NAA ratio demonstrated an even stronger correlation with the change in mJOA score after surgery (P=0.0065; R2=0.4219). Neither the Cho/Cr ratio, nor the presence of a lactate peak or T2-weighted signal change was significantly correlated with change in mJOA score after surgery. Conclusions: MRS is a novel, noninvasive imaging modality that provides pertinent information regarding spinal cord cellular and metabolic function. In a cohort of operatively treated CSM patients, the NAA/Cr and Cho/NAA ratios were predictive of neurological outcome, as both were significantly associated with change in mJOA score after surgery.



  7. Comparative Effectiveness of Treatments for Chronic Low Back Pain: A Multiple Treatment Comparison Analysis
    imageStudy Design: A systematic review and network meta-analysis. Objective: To determine current treatment options of chronic low back pain (LBP) as defined by randomized controlled trials (RCTs) and to compare effectiveness of those treatments using a mixed-treatment comparison (MTC). Summary of Background Data: It is important to provide an evidence-based assessment of the treatment options that exist for LBP. Methods: A systematic search of RCTs was conducted in MEDLINE and the Cochrane Collaboration Library from 1990 to 2014. From the selected studies, we extracted preoperative and postoperative ODI and VAS back pain scores, additional surgeries, and complications. Standard and network meta-analytic techniques were used. Results: Twelve RCTs were included in the analysis: 5 total disk replacement (TDR) versus fusion; 1 TDR versus exercise and cognitive behavioral therapy (CBT); 5 fusion versus exercise and CBT; and 1 fusion versus physical therapy (PT). On the basis of MTC, with respect to ODI change scores, the pooled mean difference favoring fusion over exercise and CBT was 2.0 points (95% CI, −1.2 to 4.8). The pooled mean difference favoring TDR over exercise and CBT was 6.4 points (95% CI, 3.2–9.3). The pooled mean difference favoring fusion over PT was 8.8 points (95% CI, 4.1–13.6). The pooled mean differences favoring TDR over fusion was 4.4 points (95% CI, 2.37–6.63). For PT versus structured exercise with CBT, the pooled mean difference favoring exercise with CBT over PT was 6.8 points (95% CI, 1.5–12.8). For TDR versus PT, the pooled mean difference favoring TDR over PT was 13.2 points (95% CI, 8.0–18.4). Additional surgery rates were similar between treatment options. Conclusions: All 4 treatments provided some benefit to patients with chronic LBP. According to the MTC analysis, TDR may be the most effective treatment and PT the least effective treatment for chronic LBP. This review is based on a limited number of RCT studies and does not support any 1 treatment modality for all patients.



  8. Is the SIJ a Cause of Pain that can be Accurately Identified and Treated With an SI Fusion?
    imageNo abstract available



  9. The Evolution of Current Research Impact Metrics: From Bibliometrics to Altmetrics?
    imageThe prestige of publication has been based on traditional citation metrics, most commonly journal impact factor. However, the Internet has radically changed the speed, flow, and sharing of medical information. Furthermore, the explosion of social media, along with development of popular professional and scientific websites and blogs, has led to the need for alternative metrics, known as altmetrics, to quantify the wider impact of research. We explore the evolution of current research impact metrics and examine the evolving role of altmetrics in measuring the wider impact of research. We suggest that altmetrics used in research evaluation should be part of an informed peer-review process such as traditional metrics. Moreover, results based on altmetrics must not lead to direct decision making about research, but instead, should be used to assist experts in making decisions. Finally, traditional and alternative metrics should complement, not replace, each other in the peer-review process.



  10. Comparison of the Clinical and Radiographic Results Between Cervical Artificial Disk Replacement and Anterior Cervical Fusion: A 6-Year Prospective Nonrandomized Comparative Study
    imageStudy Design: Prospective nonrandomized comparative study. Objective: To compare the long-term clinical and radiographic results of cervical artificial disk replacement (CADR) and anterior cervical discectomy and fusion (ACDF), and to provide our evidence if CADR could reduce adjacent segment degeneration (ASD). Summary of Background Data: CADR is widely used in spine surgery today. Despite the short-term results of it having been ascertained, the long-term results are still under observation. Meanwhile it is still debatable if CADR could reduce ASD in the long run. Materials and Methods: Sixty-three patients with cervical myelopathy who underwent CADR (28) or ACDF (35) with a minimum follow-up of 68 months were included. Japanese Orthopaedic Association score, neck disability index, and Odom’s scale were used to evaluate the clinical outcomes. Radiographs, computed tomography, and magnetic resonance imaging were used to evaluate the radiographic outcomes. Results: Both CADR and ACDF groups showed significant improvement on Japanese Orthopaedic Association scores and neck disability index, and there was no significant difference between the 2 groups. The sagittal alignment was maintained for both the groups. The C2–C7 range of motion had no significant change for CADR group, whereas it significantly decreased for ACDF group. The range of motion at index level of CADR patients decreased from 9.5±3.7 degrees before surgery to 7.0±3.0 degrees at 3 months after surgery (P<0.001), and it was maintained to 6.6±4.1 degrees at last follow-up without significant decrease (P=0.448). We used radiographic data to evaluate ASD and we found the incidence of ASD was significantly lower for CADR group than ACDF group. Conclusions: The clinical and radiographic results of CADR over 6-year follow-up are basically satisfying. Compared with ACDF, CADR could better preserve physiological motion and biomechanics of cervical spine, and reduce the occurrence of ASD.


  11. Payor Reform Opportunities for Spine Surgery: Part I: Background and Stimulus for Bundled Payments
    Spine surgery, and orthopedic surgery overall, is being increasingly scrutinized by payors due to large projected increases in utilization. The unsustainability of the fee-for-service payment system has lead payors to investigate novel value and risk-based contracting strategies on an episode of care basis and on a population health basis. These forays into progressive models for spine surgery have been supported by the successes demonstrated by advanced payor reform programs from The Centers for Medicare and Medicaid Services in other areas of musculoskeletal medicine. Whether they are focused on lower extremity arthroplasty or spinal surgery, these pressures are forcing hospitals and physicians to align to improve quality and reduce costs through new structures and relationships. However, in many respects spine surgery has been years behind the wave of market pressures seen in other orthopedic subspecialties, such as arthroplasty. As such, the recognition and understanding of the forces and motivations driving the massive pressures responsible for these will better equip the spine surgeon to adapt and ultimately master such transformations.



  12. Analysis of the Factors That Could Predict Segmental Range of Motion After Cervical Artificial Disk Replacement: A 7-Year Follow-up Study
    imageStudy Design: A retrospective cohort study. Objective: To identify the potential preoperative factors and surgical technique factors that are associated with long-term range of motion (ROM) after surgery. Further, this article aimed to guide selection of patients with cervical artificial disk replacement and a fine surgical technique. Summary of Background Data: Segmental ROM is the most important parameter concerning cervical kinematics after a cervical artificial disk replacement. There are few researches regarding the influencing factors on postoperative ROM, and consistent results have not yet been reported. Methods: The cohort comprised a total of 68 disks implanted into 57 patients who were retrospectively analyzed. The mean follow-up period was 84.1 months. Segmental ROM and other useful parameters were measured using lateral neutral, extension, and flexion radiographs, which were obtained preoperatively, 3 months after surgery, and at last follow-up. Preoperative CT and clinical assessment were also used. To find out associated factors, the patients were divided into 2 groups according to the segmental ROM at last follow-up. Results: After surgery, the clinical outcomes were satisfactory. The segmental ROM at last follow-up (7.8±4.3 degrees) was preserved without significant change from preoperative ROM (8.8±3.8 degrees). The patients who had a better segmental ROM after surgery were found to have a higher preoperative segmental ROM, a younger age, a better disk insertion angle, and disk insertion depth. These 4 factors were identified as independent risk factors (P=0.027, 0.017, 0.036, and 0.046, respectively) for long-term ROM. Conclusions: The postoperative long-term, segmental ROM was well preserved and found to be affected by the preoperative segmental ROM, patient’s age, disk insertion angle, and disk insertion depth.



  13. Analysis of Cervical Angiograms in Cervical Spine Trauma Patients, Does it Make a Difference?
    Study Design: Retrospective review. Objective: To evaluate computed tomography angiogram (CTA) use for diagnosing blunt vertebral artery injury (BVAI) at a single institution, to assess the incidence of BVAI in the studied population, and determine if diagnosis affected care. We also wanted to evaluate if testing and treatment resulted in complications. Summary of Background Data: BVAI is an example of a previously underdiagnosed injury. Ease of CTA has simplified vertebral artery evaluation. Injury to the vertebral or carotid arteries is diagnosed in approximately 0.1% of blunt trauma patients when there is high clinical suspicion, or when symptoms of central nervous system damage are apparent on initial examination. Routine screening of asymptomatic patients increases the incidence to approximately 1%. Materials and Methods: After IRB approval, the hospital trauma registry identified patients aged 18–89 presenting with cervical spine fracture from 2006 to 2011. A retrospective review of charts was completed. Data collection included demographic data, fracture pattern, and neurological findings. The indications for and the results of CTA was also reviewed. The type of treatment and any complications were recorded. Results: A total of 637 charts reviewed. A total of 108 subjects underwent CTA/magnetic resonance angiography; 15 diagnosed with VAI injury. Four received treatment. There were no complications from imaging or treatment of BVAI. Eight subjects without CTA evaluation presented with symptoms potentially related to injury on arrival. Three had neurological decline, although none were eligible for treatment. No routine diagnostic/treatment protocol for vertebral arteries was found at our institution. Conclusions: Although neurological sequelae after VAI can be devastating, routine screening after cervical spine fracture may not be warranted. Beside cost, our study suggests it is rarely associated with symptoms, and the asymptomatic patient rarely receives treatment due to concomitant injuries. Our study reinforces the need for further research to establish protocols so that patient-appropriate, cost-effective evaluation and treatment can be provided.



  14. Minimum 5-year Follow-up Results for Occipitocervical Fusion Using the Screw-Rod System in Craniocervical Instability
    imageStudy Design: Retrospective clinical study. Objective: To evaluate the clinical outcome of patients who had undergone occipitocervical (OC) fusion using pedicle screws and rods over a minimum 5-year follow-up. Summary of Background Data: Few studies have evaluated occipitocervical (OC) fusion using pedicle screws and rods for long-term follow-up. Methods: Twenty-seven consecutive patients treated underwent posterior OC fusion using pedicle screws and rods over a minimum 5-year follow-up. The Modified McCormick scale to grade a patient’s functional status and the Japanese Orthopaedic Association (JOA) scoring system were used to evaluate preoperative and postoperative neurological function. We assessed fusion by both direct and indirect evidence; bony trabeculae at the graft-recipient interface on lateral cervical radiographs and sagittal computed tomography reconstruction was considered direct evidence of union. Results: The mean follow-up period was 7.2 years (5–14 y). JOA scores were 8.1±3.8 before surgery and 11.7±3.7 at the final follow-up. The recovery rate calculated from the JOA scores was 42.0±30.0%. Functional status did improve at least 1 grade according to the modified McCormick scale in 18 patients (66.7%). There was no deterioration at the final follow-up. There were postoperative implant-related complications in 8 patients (29.6%): loosening of pedicle screws in 2, rod breakage in 2, plate breakage in 1, screw breakage in 1, pullout of pedicle screws in 1, and wiring induced myelopathy in 1 patient. The average duration between surgery and implant failure was 31.2 months (12–60 mo) except for 2. Conclusions: Sufficient bone grafting, proper decortication of the bone bed, using thicker and high stiffness rods, and ultra-high molecular weight polyethylene tape as a fixation or reinforcement of implant may help prevent implant failure.



  15. Cortical Bone Trajectory for Thoracic Pedicle Screws: A Technical Note
    imageStudy Design: A morphometric measurement of new thoracic pedicle screw trajectory using computed tomography and a biomechanical study on cadaveric thoracic vertebrae using insertional torque. Objective: To introduce a new thoracic pedicle screw trajectory which maximizes engagement with denser bone. Summary of Background Data: Cortical bone trajectory (CBT) which maximizes the thread contact with cortical bone provides enhanced screw purchase. Despite the increased use of CBT screws in the lumbar spine, no study has yet reported the insertional technique for thoracic CBT. Methods: First, the computed tomography scans of 50 adults were studied for morphometric measurement of lower thoracic CBT. The starting point was determined to be the intersection of the lateral two thirds of the superior articular process and the inferior border of the transverse process. The trajectory was straight forward in the axial plane angulated cranially targeting the posterior third of the superior endplate. The maximum diameter, length, and the cephalad angle were investigated. Next, the insertional torque of pedicle screws using this new technique was measured and compared with that of the traditional technique on 24 cadaveric thoracic vertebrae. Results: All morphometric parameters of thoracic CBT increased from T9 to T12 (the mean diameter: from 5.8 mm at T9 to 8.5 mm at T12; the length: from 29.7 mm at T9 to 32.0 mm at T12; and the cephalad angle: from 21.4 degrees at T9 to 27.6 degrees at T12). The mean maximum insertional torque of CBT screws and traditional screws were 1.02±0.25 and 0.66±0.15 Nm, respectively. The new technique demonstrated average 53.8% higher torque than the traditional technique (P<0.01). Conclusions: The detailed morphometric measurement and favorable screw fixation stability of thoracic CBT are reported. The insertional torque using thoracic CBT technique was 53.8% higher than that of the traditional technique.


  16. Influence of Myelography and Postmyelographic CT on Therapeutic Decisions in Degenerative Diseases of the Cervical Spine
    imageStudy Design: A retrospective analysis of clinical records and radiologic imaging by 3 independent reviewers to assess the indication for surgical treatment with and without myelography and postmyelographic computed tomography (MCT). Objective: To evaluate whether myelography and MCT obtained in addition to magnetic resonance imaging (MRI) influence therapeutic decisions in degenerative diseases of the cervical spine. Summary of Background Data: MRI has become the standard examination in spinal diseases. The role of myelography and MCT is not clearly defined in the modern diagnostic setup. In many departments, they are used if MRI leaves some diagnostic uncertainty. It has not been examined yet whether additional myelography and MCT change therapeutic strategies. Materials and Methods: Three investigators independently reviewed the anonymized clinical data and image files of 105 patients who had all undergone MRI, myelography, and MCT. They determined their treatment decisions after each of 2 assessment rounds based on the following: (1) MRI and, if available, native CT, and plain radiographs. (2) Additional myelography and MCT. The intraobserver variability was the primary endpoint. Results: Myelography and MCT had been performed in multilevel disease, recurrent complaints after surgery, or if MRI had not revealed a clear finding. The intraobserver variability was 26.3% and varied markedly between the 3 investigators (17%–41 %). It was the highest in cases of multilevel disease. If noninvasive imaging included native CT and plain radiographs, the intraobserver variability was significantly reduced to 10.3%. Conclusions: In unclear cases of degenerative disorders of the cervical spine, particularly multilevel stenosis, myelography and MCT add relevant information for therapeutic decisions in more than a quarter of the patients in comparison with MRI as the sole diagnostic modality, and changes therapeutic strategies. However, a significant part of the information drawn out of myelography and MCT can be obtained by a completion of noninvasive examinations (native CT and radiographs).



  17. Safety and Efficacy Study of an Ozone Laser Combined Therapy Using Puncture Needle in the Treatment of Patients With Cervical Spondylosis
    imageStudy Design and Methods: Fifty-eight patients with cervical spondylosis (CS) were treated with patented technology of ozone laser combined therapy using puncture needle between August 2008 and February 2010. Visual Analogue Scale (VAS) score changes before and 6 months after surgery and MacNab score criteria 6 months after surgery were analyzed. Background and Objective: CS normally occurs over the age of 50 and broadly presents as either myelopathy or radiculopathy. Complementary treatment strategies have long been envisaged as a possible alternative in alleviating neck pain associated with CS; however, it is still in moderate use due to lack of adequate and convincing evidence of its safety and efficacy. The current study was to define and understand the therapeutic effects and safety of a newly developed patented technology, ozone, and laser via puncture needle, in the treatment of CS. Results: The VAS score of preoperative neck and shoulder pain was (6.57±1.34) scores, which decreased to 1.80±0.65 at 1-week postsurgery, and was completely alleviated by the end of 1 month (VAS score 0–2 after 1, 3, and 6 mo after surgery) (Kruskal-Wallis rank-sum test, H=1.680, P=0.000). VAS scores did not exhibit any significant rebound within 6 months after surgery (29 patients were excellent; 23 good; and 6 were fair, overall excellent, and good rate of 89.6%). Conclusion: Ozone and laser combined therapy via puncture needle for the treatment of CS is safe and effective.



  18. A Radiographic Analysis of Cervical Sagittal Alignment in Adolescent Idiopathic Cervical Kyphosis
    imageObjective: The aim of this study was to analyze the radiologic features of adolescent idiopathic cervical kyphosis. Summary of Background Data: There are few previous reports about radiographic analysis of cervical sagittal alignment of adolescent idiopathic cervical kyphosis. A new method was proposed in this article to evaluate the severity of cervical kyphosis. Patients and Methods: A total of 41 adolescent patients with cervical kyphosis were reviewed. Several angles were measured from the radiographs utilizing the 2-line Cobb method and Harrison posterior tangent method. Ishihara’s Curvature Index (CI), Kyphosis Index (KI), kyphosis levels, and the apex of the kyphosis were also measured. Results: The results showed that the apex of the kyphosis is located at the posterior-superior edge of C4 (70.7%) and C5 (29.3%). C2–C7 angles ranged from 4.7 to 71.3 degrees (36.2±13.6 degrees) and from 9.8 to 83.1 degrees (36.4±15.1 degrees) in the above 2 methods, respectively. Local angles of kyphotic area ranged from 21.8 to 96.3 degrees (50.5±23.7 degrees) in 2-line Cobb method and from 19.8 to 105.6 degrees (52.0±19.5 degrees) in Harrison posterior tangent method. CI and KI ranged from 8.6 to 79.8 (36.8±16.7) and 15.2 to 141.9 (50.6±23.7), respectively. Statistical analysis showed that there was significant positive correlation between KI and kyphosis angle. Conclusions: In adolescent idiopathic cervical kyphosis, the alteration of the sagittal profile only occurs on partial cervical alignment rather than the whole cervical spine. The apex of the kyphosis locates at posterior-superior edge of the vertebrae. It seems that KI can accurately depict the severity of cervical kyphosis.



  19. Factors Affecting the Nonlinear Force Versus Distraction Height Curves in an In Vitro C5–C6 Anterior Cervical Distraction Model
    imageStudy Design: In vitro biomechanical study of cervical intervertebral distraction. Objective: To investigate the forces required for distraction to different heights in an in vitro C5–C6 anterior cervical distraction model, focusing on the influence of the intervertebral disk, posterior longitudinal ligament (PLL), and ligamentum flavum (LF). Summary of Background Data: No previous studies have reported on the forces required for distraction to various heights or the factors resisting distraction in anterior cervical discectomy and fusion. Materials and Methods: Anterior cervical distraction at C5–C6 was performed in 6 cadaveric specimens using a biomechanical testing machine, under 4 conditions: A, before disk removal; B, after disk removal; C, after disk and PLL removal; and D, after disk and PLL removal and cutting of the LF. Distraction was performed from 0 to 10 mm at a constant velocity (5 mm/min). Force and distraction height were recorded automatically. Results: The force required increased with distraction height under all 4 conditions. There was a sudden increase in force required at 6–7 mm under conditions B and C, but not D. Under condition A, distraction to 5 mm required a force of 268.3±38.87 N. Under conditions B and C, distraction to 6 mm required <15 N, and further distraction required dramatically increased force, with distraction to 10 mm requiring 115.4±10.67 and 68.4±9.67 N, respectively. Under condition D, no marked increase in force was recorded. Conclusions: Distraction of the intervertebral space was much easier after disk removal. An intact LF caused a sudden marked increase in the force required for distraction, possibly indicating the point at which the LF was fully stretched. This increase in resistance may help to determine the optimal distraction height to avoid stress to the endplate spacer.



  20. A New Entrance Technique for C2 Pedicle Screw Placement and the Use in Patients With Atlantoaxial Instability
    imageStudy Design: A prospective study and a technique note. Objectives: To introduce a new entrance technique for C2 pedicle screw placement and to measure the related linear and angular parameters about the entrance point on computed tomography (CT) images. The safety of this technique for patients with atlantoaxial instability was also evaluated. Background Data: Although earlier studies have introduced different methods for C2 pedicle screw placement, the entry points and the angular parameters may be variable. Few studies have established a fixed entry point on the basis of the anatomic structure of C2 for pedicle screw placement. Methods: A total of 60 dry C2 vertebrae were obtained for anatomic measurement in the study. The posterior bilateral nutrient foramens of C2 lamina were selected as the entry points for pedicle screw placement. The foramens were marked with needles and then the vertebrae underwent CT scan. The axial and sagittal planes of C2 pedicles were harvested and 4 linear and 2 angular parameters about the entry point were determined. After that, we used the entrance technique on 31 patients with atlantoaxial instability in a prospective study. CT of the cervical spine was performed to evaluate the safety of the entrance technique. Results: The nutrient foramens exist in 97% of the left lamina and 93% of the right lamina of the C2 vertebra. The overall mean distance from the entry point (nutrient foramen) to the superior border of lamina (PSD), to the inferior border of lamina (PID), to the medial border of the pedicle (PMD), and the length of pedicle screw trajectory (PL, transit the pedicle center) were 3.32±0.63, 8.33±1.21, 6.85±1.00, and 24.47±1.51, respectively. The averaged transverse angle (α) on the axial plane and the superior angle (β) on the sagittal plane were 19.83±3.83 and 30.12±6.02 degrees, respectively. Then, 31 patients underwent bilateral C2 pedicle screw fixation without screw violation into the spinal canal or vertebral artery injury by the new entrance technique. The overall mean angles α and β and the length of the pedicle screw were 17.52±3.81 and 34.29±4.18 degrees and 25.85±2.06 mm, respectively. No statistical differences were found in these 3 parameters between the dry C2 vertebrae and the C2 vertebrae of patients who underwent the surgery (P>0.05). Conclusions: Using the posterior bilateral nutrient foramens of the C2 lamina as the entry point is a helpful intraoperative landmark for C2 pedicle screw placement.


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