RESUMO
STUDY DESIGN: A radiographic analysis of the anatomy of the C1 lateral mass using computed tomography (CT) scans and Mimics software. OBJECTIVE: To define the anatomy of the C1 lateral mass and make recommendations for optimal entry point and trajectory for anterior C1 lateral mass screws. SUMMARY OF BACKGROUND DATA: Although various posterior insertion angles and entry points for screw insertion have been proposed for posterior C1 lateral mass screws, no large series have been performed to assess the ideal entry point and optimal trajectory for anterior C1 lateral mass screw placement. MATERIALS AND METHODS: The C1 lateral mass was evaluated using CT scans and a 3-dimensional imaging application (Mimics software). Measuring the space available for the anterior C1 lateral mass screw (SAS) at different camber angles from 0 to 30 degrees (5-degree intervals) was performed to identify the ideal camber angle of insertion. Measuring the range of sagittal angles was performed to calculate the ideal sagittal angle. Other measurements involving the height of the C1 lateral mass were also made. RESULTS: The optimal screw entry point was found to be located on the anterior surface of the atlas 12.88 mm (±1.10 mm) lateral to the center of the anterior tubercle. This optimal entry point was found to be 6.81 mm (±0.59 mm) superior to the anterior edge of the atlas inferior articulating process. The mean ideal camber angle was 20.92 degrees laterally and the mean ideal sagittal angle was 5.80 degrees downward. CONCLUSIONS: These measurements define the optimal entry point and trajectory for anterior C1 lateral mass screws and facilitate anterior C1 lateral mass screw placement. A thorough understanding of the local anatomy may decrease the risk of injury to the spinal cord, vertebral artery, and internal carotid artery. Delineating the anatomy in each case with preoperative 3D CT evaluation is recommended.
Assuntos
Parafusos Ósseos , Vértebras Cervicais/cirurgia , Adolescente , Adulto , Fenômenos Biomecânicos , Vértebras Cervicais/diagnóstico por imagem , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Osteotomia , Tomografia Computadorizada por Raios X , Adulto JovemRESUMO
STUDY DESIGN: Retrospective analysis of a prospective cohort. OBJECTIVE: Change in cervical angular alignment may be associated with dysphagia. SUMMARY OF BACKGROUND DATA: Bony deformities of the cervical spine may be associated with secondary contractures of soft tissues in the neck. Acute surgical deformity correction causes in changes in soft tissue tension in the anterior neck, resulting in dysphagia. METHODS: The study population included patients undergoing 1 and 2 level elective anterior cervical discectomy and fusion for cervical myelopathy or radiculopathy. Preoperative and postoperative radiographs at 2 weeks were measured by a blinded observer for C2-C7 endplate angle, C2-C7 posterior vertebral body length, and occipital condyle plumb line distance on upright lateral radiographs at 2, 6, and 12 weeks postoperatively. Patients were prospectively queried about dysphagia incidence and severity using a numeric rating scale. Multiple linear regression analysis was used to determine the effect of change in radiographic parameters controlling for demographic characteristics. RESULTS: The study population included 25 patients with complete radiographs. The mean change in C2-C7 angle was -0.6 degrees (SD 9), the mean change in C2-C7 length was 1.7 mm (SD 26), the mean change in occipital condyle plumb line distance was 2.3 mm (SD 20).Multiple linear regression analysis was performed including operative time, age, sex, number of levels, and change in radiographic parameters as independent variables and using dysphagia score as the dependent variable. The change in C2-C7 angle and operative time were the only statistically significant predictors of change in dysphagia at 2 and 6 weeks postoperatively. CONCLUSIONS: These results indicate that lordotic change in spinal alignment and longer operative times are associated with increased postoperative dysphagia. Surgeons should counsel patients in whom a large angular correction is expected about the possibility for postoperative dysphagia. Furthermore, future studies on dysphagia incidence should include radiographic alignment as an independent predictor of dysphagia.
Assuntos
Vértebras Cervicais/cirurgia , Transtornos de Deglutição/etiologia , Discotomia/efeitos adversos , Complicações Pós-Operatórias/etiologia , Postura , Fusão Vertebral/efeitos adversos , Adulto , Vértebras Cervicais/patologia , Estudos de Coortes , Feminino , Humanos , Modelos Lineares , Masculino , Pessoa de Meia-Idade , Radiculopatia/cirurgia , Doenças da Medula Espinal/cirurgiaRESUMO
STUDY DESIGN: Retrospective case series. OBJECTIVE: To determine whether bed rest is a risk factor for specific medical complications. SUMMARY OF BACKGROUND DATA: Flat bed rest after incidental durotomy is commonly used to reduce the risk of CSF leakage and associated complications. METHODS: Retrospective case series of consecutive patients after lumbar laminectomy were identified. Medical records were reviewed for duration of bed rest and complications (pulmonary, wound, neurological, gastrointestinal, and urinary) in the chart notes, repair methods, subfascial drain placement, consultant notes, imaging reports, and discharge summaries. Patients were compared with duration of bed rest >24 hours versus duration of bed rest ≤24 hours. The incidence of complications was compared between groups using the Fisher exact test. RESULTS: There were a total of 42 patients with incidental durotomy. There were 18 patients in the bed rest ≤24 hours group and 24 patients in the bed rest >24 hours group. Comparing the bed rest ≤24 hours to bed rest >24 hours patients, there was no statistically significant difference in the incidence of postdurotomy-related neurological complications, wound complications, and need for revision surgery. There was a statistically significant decrease in the incidence of total medical complications in the ≤24-hour group (0% vs. 50%, P=0.0003). CONCLUSION: There was an increased incidence of medical complications in the bed rest group >24 hours. Flat bed rest after modern dural repair method may not be a necessity in all cases and may be associated with a higher incidence of medical complications.
Assuntos
Repouso em Cama/efeitos adversos , Rinorreia de Líquido Cefalorraquidiano/etiologia , Dura-Máter/lesões , Complicações Intraoperatórias/etiologia , Laminectomia/efeitos adversos , Pneumopatias/etiologia , Rinorreia de Líquido Cefalorraquidiano/prevenção & controle , Feminino , Humanos , Complicações Intraoperatórias/prevenção & controle , Vértebras Lombares/cirurgia , Pneumopatias/prevenção & controle , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos , Traumatismos da Medula Espinal/cirurgia , Fatores de TempoRESUMO
STUDY DESIGN: A retrospective case series describing teardrop fracture of the axis. OBJECT: The purpose of the study was to clarify the clinical features, the mechanism of injury, and the potential instability of extension teardrop fractures of the axis, so as to emphasize the importance of recognizing this injury as a separate entity. SUMMARY OF BACKGROUND DATA: Teardrop fractures of the axis are rare spinal fractures, comprising only a small percentage of all injuries of the cervical spine. The stability of this fracture pattern has been a matter of debate leading to controversy regarding treatment strategies and the need for stabilization. METHODS: We retrospectively reviewed data collected from 16 patients to document the mechanism of injury, neurological deficit, treatment and clinical outcome, and imaging findings. RESULTS: Extension teardrop fractures accounted for approximately 8.9% of the upper cervical spinal injuries and 12.7% of axis fractures at the authors' institution over the same period. Six patients (4 males and 2 females) underwent surgery (4 by an anterior approach, 2 by a posterior approach). Ten cases underwent Halo-vest immobilization for a period between 6 and 12 weeks. At final follow-up, 14 cases achieved excellent results, whereas 2 patients complained of mild residual neck pain. Maximum cranial-caudal dimensions of the fragments were between 5 and 24 mm (average, 12.9 mm), and the transverse dimensions were between 5 and 22 mm (average, 11.1 mm). Fragment displacement ranged from 1 to 9 mm (average, 3.5 mm), whereas fragment rotation ranged from 10 to 52 degrees (average, 24.4 degrees) in the sagittal plane. CONCLUSIONS: Most patients with an extension teardrop fracture of the axis can be treated conservatively. On the basis of this case series, the authors suggest that large fragment size, displacement or angulation, intervertebral disk injury, neurologic deficit, or signs of instability are reasonable indications for surgical treatment.
Assuntos
Vértebra Cervical Áxis/lesões , Fraturas da Coluna Vertebral/terapia , Adulto , Idoso , Vértebra Cervical Áxis/diagnóstico por imagem , Feminino , Fixação Interna de Fraturas , Humanos , Escala de Gravidade do Ferimento , Masculino , Pessoa de Meia-Idade , Medição da Dor , Radiografia , Estudos Retrospectivos , Fraturas da Coluna Vertebral/diagnóstico por imagem , Fraturas da Coluna Vertebral/patologia , Fraturas da Coluna Vertebral/cirurgia , Resultado do Tratamento , Adulto JovemRESUMO
STUDY DESIGN: Anatomic study of the C1 lateral mass using fine-cut computed tomographic scans and Mimics software. OBJECTIVE: To investigate the optimal entry point, medial angles, and effective length for safe fixation using posterior C1 lateral mass screws. SUMMARY OF BACKGROUND DATA: Placing posterior C1 lateral mass screws is technically demanding, and a misplaced screw can result in injury to the vertebral artery, spinal cord, or internal carotid artery. Although various insertion angles have been proposed for posterior C1 lateral mass screw, no clear consensus has been reached on the ideal medial angle of the C1 lateral mass. METHODS: The C1 lateral masses were evaluated using computed tomographic scans and Mimics software in 70 patients. The effective width and effective screw length of posterior C1 lateral mass screws were measured at different medial angulations relative to the midline sagittal plane. The height (H) for screw entry point on the posterior surface of C1 lateral mass and the distance (D) between screw entry point and the intersection of the midline sagittal plane and the posterior arch of the atlas were also measured. RESULTS: The mean height (H) for screw entry on the posterior surface of the lateral mass was 4.25 mm, the mean distance (D) between screw entry point and the intersection of the midsagittal plane and the posterior arch of the atlas was 27.62 mm. The optimal medial angle was 20.86° with a corresponding effective width of 10.56 mm and effective screw length of 21.87 mm. CONCLUSION: This study helps to define the specific anatomy related to C1 posterior lateral mass screw placement in an effort to facilitate instrumentation. However, variation is seen in lateral mass anatomy, and this study must be combined with customized surgical planning that includes advanced imaging for safe and effective instrumentation. LEVEL OF EVIDENCE: 1.
Assuntos
Articulação Atlantoaxial/cirurgia , Parafusos Ósseos , Atlas Cervical/cirurgia , Fusão Vertebral/métodos , Adolescente , Adulto , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Cervicalgia/cirurgia , Adulto JovemRESUMO
STUDY DESIGN: Laboratory study. OBJECTIVE: To evaluate the differential gene expression of cytokines and growth factors in anterior versus posterior annulus fibrosus (AF) intervertebral disc (IVD) specimens. SUMMARY OF BACKGROUND DATA: Histological analysis has demonstrated regional differences in vascular and neural ingrowth in the IVD, and similar differences may exist for cytokine and growth factor expression in patients with degenerative disc disease (DDD). Regional expression of these cytokines may also be related to the pain experienced in DDD. METHODS: IVD tissue was obtained from patients undergoing anterior lumbar interbody fusion surgery for back pain with radiological evidence of disc degeneration. For a control group, the discs of patients undergoing anterior lumbar discectomy for degenerative scoliosis were obtained as well. The tissue was carefully removed and separated into anterior and posterior AF. After tissue processing, an antibody array was completed to determine expression levels of 42 cytokines and growth factors. RESULTS: Nine discs from 7 patients with DDD and 5 discs from 2 patients with scoliosis were analyzed. In the DDD group, there were 10 cytokines and growth factors with significantly increased expression in the posterior AF versus the anterior AF ([interleukin] IL-4, IL-5, IL-6, M-CSF, MDC, tumor necrosis factor ß, EGF, IGF-1, angiogenin, leptin). In the scoliosis group, only angiogenin and PDGF-BB demonstrated increased expression in the posterior AF. No cytokines or growth factors had increased expression in the anterior AF compared with posterior AF. CONCLUSION: The posterior AF expresses increased levels of cytokines and growth factors compared with the anterior AF in patients with DDD. This differential expression may be important for targeting treatment of painful IVDs. LEVEL OF EVIDENCE: N/A.
Assuntos
Citocinas/biossíntese , Regulação da Expressão Gênica , Peptídeos e Proteínas de Sinalização Intercelular/biossíntese , Disco Intervertebral/metabolismo , Adulto , Idoso , Citocinas/genética , Feminino , Humanos , Peptídeos e Proteínas de Sinalização Intercelular/genética , Disco Intervertebral/patologia , Degeneração do Disco Intervertebral/genética , Degeneração do Disco Intervertebral/metabolismo , Degeneração do Disco Intervertebral/patologia , Masculino , Pessoa de Meia-IdadeRESUMO
STUDY DESIGN: Retrospective case series. OBJECTIVE: The objectives of this study were to (1) determine the rate of postoperative urinary retention (POUR) in a series of patients undergoing lumbar spine surgery, (2) compare length of hospital stay between patients who developed POUR and patients who did not, and (3) identify the patient and surgical factors associated with the development of POUR. SUMMARY OF BACKGROUND DATA: Although POUR is a common complication in many surgical subspecialties, sparse literature is present regarding development of POUR after posterior lumbar surgical procedures. METHODS: A retrospective review was conducted of all posterior lumbar surgery cases performed at single institute from July 2008 to July 2012. Data collected included demographic variables (age, sex, body mass index), length of stay, comorbid medical conditions, and surgical data. The Wilcoxon rank sum test with continuity correction was used to compare length of hospital stay between patients who developed POUR and patients who did not. A multivariate logistic regression model was created using all patient and surgical factors and systematically pruned of variables not improving overall predictive power. RESULTS: A total of 647 patients (291 decompression, 356 decompression and fusion) were included in the study. Of 647 patients, 36 had urinary retention after lumbar spine surgery (5.6%). Patients who developed POUR had a longer length of stay than patients who did not develop POUR (3.94 d vs. 2.34 d; P=0.005). Male sex, benign prostatic hyperplasia, age, diabetes, and depression were significantly associated with development of POUR (odds ratio=3.05, 9.82, 1.04, 3.32, and 2.51, respectively). Smoking was inversely associated with the development of POUR (odds ratio=0.45). CONCLUSION: The risk of developing POUR after posterior lumbar spine surgery is approximately 5%. Male sex, benign prostatic hyperplasia, age, diabetes, and depression were significantly associated with the POUR group. Patients who developed POUR had a greater length of hospital stay. LEVEL OF EVIDENCE: 4.
Assuntos
Descompressão Cirúrgica/efeitos adversos , Vértebras Lombares/cirurgia , Doenças da Coluna Vertebral/cirurgia , Fusão Vertebral/efeitos adversos , Retenção Urinária/epidemiologia , Retenção Urinária/etiologia , Adolescente , Adulto , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , Comorbidade , Depressão/epidemiologia , Diabetes Mellitus/epidemiologia , Feminino , Humanos , Tempo de Internação , Masculino , Pessoa de Meia-Idade , Hiperplasia Prostática/epidemiologia , Estudos Retrospectivos , Fatores de Risco , Fatores Sexuais , Fumar/epidemiologia , Adulto JovemRESUMO
STUDY DESIGN: Retrospective review. OBJECTIVE: (1) To describe change in treatment patterns for degenerative spondylolisthesis (DS). (2) To report regional variation in treatment of DS. (3) To describe variation in surgeon-reported outcomes for DS based on treatment. SUMMARY OF BACKGROUND DATA: Spinal stenosis associated with DS is commonly treated with decompression and fusion but little is known about the optimal fusion technique. During a 6-month period, American Board of Orthopaedic Surgery step II candidates submit procedure lists; these lists have been stored in an electronic database since 1999. METHODS: The American Board of Orthopaedic Surgery database was retrospectively queried to identify patients who underwent surgery for DS from 1999 to 2011. Included patients underwent uninstrumented fusion, fusion with posterior instrumentation, fusion using interbody device, or decompression without fusion. Utilization of these procedures was analyzed by year and geographic region. RESULTS: The study period included 5639 cases; the annual number of cases doubled during the study period. The percentage of cases treated with interbody fusion (IF) increased significantly throughout the study period, from 13.6% (1999-2001) to 32% (2009-2011) (P<0.001). The percentage of DS cases treated with posterolateral fusion peaked in 2003 then decreased as the rate of IF increased. In 2011, the rates of posterolateral fusion (40%) and posterolateral fusion with IF (37%) were nearly identical. The Northwest had the highest rate of IF (41%), >10% higher than any other region (P<0.001) and more than 23% higher than the Southeast (P<0.001). CONCLUSION: Despite little evidence guiding treatment strategy for DS, national treatment patterns have changed dramatically during the past 13 years. The rapid adoption of IF and substantial regional variation in treatment utilization patterns raises questions about drivers of change including perceptions about associated fusion rates, the importance of sagittal balance and differential reimbursement. LEVEL OF EVIDENCE: 4.
Assuntos
Vértebras Lombares/cirurgia , Fusão Vertebral/tendências , Espondilolistese/cirurgia , Descompressão Cirúrgica/métodos , Descompressão Cirúrgica/estatística & dados numéricos , Descompressão Cirúrgica/tendências , Humanos , Fixadores Internos/estatística & dados numéricos , Ortopedia/estatística & dados numéricos , Ortopedia/tendências , Complicações Pós-Operatórias/epidemiologia , Padrões de Prática Médica/estatística & dados numéricos , Estudos Retrospectivos , Fusão Vertebral/instrumentação , Fusão Vertebral/métodos , Fusão Vertebral/estatística & dados numéricos , Estenose Espinal/cirurgia , Resultado do Tratamento , Estados Unidos/epidemiologiaRESUMO
STUDY DESIGN: This is a retrospective, clinical, and radiologic study of posterior reduction and fusion of the C1 arch in the treatment of unstable Jefferson fractures. OBJECTIVE: The aim of the study was to describe a new motion-preserving surgical technique in the treatment of unstable Jefferson fracture. SUMMARY OF BACKGROUND DATA: The management of unstable Jefferson fractures remains controversial. The majority of C1 fractures can be effectively treated nonoperatively with external immobilization unless there is an injury to the transverse atlantal ligament (TAL). Conservative treatment usually involves immobilization for a long time in Halo vest, whereas surgical intervention generally involves C1-C2 fusion, eliminating the range of motion of the upper cervical spine. We propose a novel method for the treatment of unstable Jefferson fractures without restricting the range of motion. METHODS: A retrospective review of 12 patients with unstable C1 fractures between April 2008 and October 2011 was performed. They were treated by inserting bilateral posterior C1 pedicle screws or lateral mass screws interconnected by a transversal rod to achieve internal fixation. There were 8 men and 4 women, with an average age of 35.6 years (range, 20-60 y). Presenting symptoms included neck pain, stiffness, and decreased range of motion but none had neurological injury. Seven patients had bilateral posterior arch fractures associated with unilateral anterior arch fractures (posterior 3/4 Jefferson fracture, Landells type II), and 5 had unilateral anterior and posterior arch fractures (half-ring Jefferson fracture, Landells type II). Seven patients had intact TAL, and 5 patients had fractures and avulsion of the attachment of TAL (Dickman type II). RESULTS: A total of 24 screws were inserted. Five cases had screws placed in the lateral mass: 3 because of posterior arch breakage, and 2 because the height of the posterior arch at the entry point was <4 mm. The remaining 7 cases had pedicle screw fixation. One patient had venous plexus injury during exposure of lower margin of the posterior arch; however, successful hemostasis was achieved with Gelfoam. Postoperative x-ray and computed tomography scan showed partial breach of the transverse foramen caused by a screw in 1 case, and breach of the inner cortex of the pedicle caused by screw displacement in 1 case; however, no spinal cord injury or vertebral artery injury was found. The remaining screws were in good position. Patients were followed up for 6-40 months (average, 22 mo). All cases had recovery of range of motion of the cervical spine to the preinjury level by 3-6 months after surgery, with resolution of pain. At 6 months follow-up, plain radiographs and computed tomography scans revealed satisfactory cervical alignment, no implant failure, and satisfactory bony fusion of the fractures; no C1-C2 instability was observed on the flexion-extension radiographs. CONCLUSIONS: C1 posterior limited construct is a valid technique and a feasible method for treating unstable Jefferson fractures, which allows preservation of the function of the craniocervical junction, without significant morbidity.
Assuntos
Vértebras Cervicais/fisiopatologia , Vértebras Cervicais/cirurgia , Fixação Interna de Fraturas/métodos , Fraturas da Coluna Vertebral/fisiopatologia , Fraturas da Coluna Vertebral/cirurgia , Adulto , Parafusos Ósseos , Vértebras Cervicais/diagnóstico por imagem , Feminino , Seguimentos , Humanos , Cuidados Intraoperatórios , Masculino , Pessoa de Meia-Idade , Cervicalgia/fisiopatologia , Cervicalgia/cirurgia , Amplitude de Movimento Articular , Fraturas da Coluna Vertebral/diagnóstico por imagem , Tomografia Computadorizada por Raios X , Adulto JovemRESUMO
STUDY DESIGN: Meta-analysis of randomized controlled trials. OBJECTIVE: To compare the reported incidence of adjacent segment disease (ASD) requiring surgical intervention between anterior cervical decompression and fusion (ACDF) and total disc arthroplasty (TDA). SUMMARY OF BACKGROUND DATA: The concern for ASD has led to the development of motion-preserving technologies such as TDA. To date, however, no known study has sought to compare the incidence of ASD between ACDF and TDA in major prospective studies. METHODS: A systematic review of IDE and non-IDE trials was performed using PubMed and Cochrane libraries. These databases were thoroughly searched for prospective randomized studies comparing ACDF and TDR. Six studies met the inclusion criteria for a meta-analysis and were used to report an overall rate of ASD for both ACDF and TDA. RESULTS: Pooling data from 6 prospective studies, the overall sample size at baseline was 1586 (ACDF = 777, TDA = 809) and at the final follow-up was 1110 giving an overall follow-up of 70%. Patients after an ACDF had a lower rate of follow-up overall than those after TDR (ACDF: 67.3% vs. TDR: 72.6%, P= 0.01). Thirty-six patients required adjacent-level surgery after an ACDF at 2 to 5 years of follow-up (6.9%) compared with 30 patients after a TDA (5.1%). The corresponding reoperation rate for ASD was 2.4 ± 1.7% per year for ACDF versus 1.1 ± 1.5% per year for TDR. These differences were not statistically significant (P= 0.44). Using a Kaplan-Meier analysis and historical data, we expect 48 patients in the ACDF group and 55 patients in the TDR group to have symptomatic disease at an adjacent level. CONCLUSION: From a meta-analysis of prospective studies, there is no difference in the rate of ASD for ACDF versus TDA. We also report an overall lower rate of follow-up for patients with ACDF than for those with TDR. Future prospective studies should continue to focus on excellent patient follow-up and accurate assessment of patient symptoms that are attributable to an adjacent level as this has been an under-reported finding in prospective studies. LEVEL OF EVIDENCE: 1.