Distinguishing Pseudomeningocele, Epidural Hematoma, and Postoperative Infection on Postoperative MRI.

STUDY DESIGN: Retrospective case series. OBJECTIVE: To identify specific magnetic resonance imaging (MRI) characteristics of epidural fluid collections associated with infection, hematoma, or cerebrospinal fluid (CSF). SUMMARY OF BACKGROUND DATA: Interpretation of postoperative MRI can be challenging after lumbar fusion. The purpose of this study was to identify specific MRI characteristics of epidural fluid collections associated with infection, hematoma, or CSF. METHODS: The study population includes consecutive patients between 2006 and 2010 who had MRIs performed within 2 weeks after elective surgery for evaluation of possible CSF fluid collection, hematoma, or infection. Patients with known previous infection (discitis/osteomyelitis) or inadequate MRIs were excluded from the study. Medical records were reviewed to determine the diagnosis (infection, hematoma, or pseudomeningocele) underlying the fluid collection. MRIs were retrospectively evaluated by a musculoskeletal radiologist and orthopedic spine attending who were blinded to the pathologic diagnosis for characteristics of the fluid collection. MRI characteristics include location of lesion: osseous involvement, disk location, anterior versus posterior versus anteroposterior, soft-tissue involvement, and iliopsoas involvement. Characteristics of the lesion include: volume of lesion, loculation, satellite lesions, multiple loci, destructive characteristics, and mass effect upon thecal sac. Enhancement was scored based upon the following variables: rim enhancement, smooth versus irregular, thin versus thick, heterogeneity, diffuse enhancement, nonenhancement, and rim thickness. General fluid collection intensity and complexity on T1, T2, and T1 postcontrast images was scored as high, medium, and low. The χ test was used to compare the incidence of imaging characteristics between patient groups (infection, hematoma, and CSF). RESULTS: Thirty-three patients were identified who met inclusion criteria. There were 13 (39%) with infection, 9 (27%) with hematoma, and 11 (33%) with CSF collection. Factors that were associated with infection were osseous involvement (R=0.392, P=0.024) and destructive characteristics (R=0.461, P=0.007). Factors that were correlated with hematoma include mass effect (R=0.515, P=0.002) and high T1-signal intensity (R=0.411, P=0.019), absence of thecal sac communication (R=-0.389, P=0.025), and absence of disk involvement (R=-0.346, P=0.048). Pseudomeningocele was associated with thecal sac communication (R=0.404, P=0.02), absence of mass effect (R=-0.48, P=0.005), low T1 signal (R=-0.364, P=0.04), and low T2 complexity (R=-0.479, P=0.005). CONCLUSION: Specific characteristics of the postoperative MRI can be used to distinguish infection from noninfectious fluid collections. The strongest predictors of infection were osseous involvement and destructive bony changes. Hematoma was associated with mass effect on the thecal sac, high T1-signal intensity, and absence of thecal sac communication and disk involvement. CSF collections were distinguished by absence of mass effect, low T2-signal complexity, low T1-signal intensity, and communication with the thecal sac.

Neurogenic Fever after Acute Traumatic Spinal Cord Injury: A Qualitative Systematic Review.

STUDY DESIGN: Systematic review. OBJECTIVE: To determine the incidence, pathogenesis, and clinical outcomes related to neurogenic fevers following traumatic spinal cord injury (SCI). METHODS: A systematic review of the literature was performed on thermodysregulation secondary to acute traumatic SCI in adult patients. A literature search was performed using PubMed (MEDLINE), Cochrane Central Register of Controlled Trials, and Scopus. Using strict inclusion and exclusion criteria, seven relevant articles were obtained. RESULTS: The incidence of fever of all origins (both known and unknown) after SCI ranged from 22.5 to 71.7% with a mean incidence of 50.6% and a median incidence of 50.0%. The incidence of fever of unknown origin (neurogenic fever) ranged from 2.6 to 27.8% with a mean incidence of 8.0% and a median incidence of 4.7%. Cervical and thoracic spinal injuries were more commonly associated with fever than lumbar injuries. In addition, complete injuries had a higher incidence of fever than incomplete injuries. The pathogenesis of neurogenic fever after acute SCI is not thoroughly understood. CONCLUSION: Neurogenic fevers are relatively common following an acute SCI; however, there is little in the scientific literature to help physicians prevent or treat this condition. The paucity of research underscored by this review demonstrates the need for further studies with larger sample sizes, focusing on incidence rate, clinical outcomes, and pathogenesis of neurogenic fever following acute traumatic SCI.

Change in Angular Alignment Is Associated With Early Dysphagia After Anterior Cervical Discectomy and Fusion.

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.

Minimally invasive versus open posterior lumbar interbody fusion: a systematic review.

BACKGROUND: Although conventional open posterior lumbar interbody fusion (open PLIF) is efficacious in management of lumbar spinal instability, concerns exist regarding lengthy hospital stays, blood loss, and postoperative complications. Minimally invasive posterior lumbar interbody fusion (MIS PLIF) may be able to address these concerns, but the research on this topic has not been systematically reviewed. QUESTIONS/PURPOSES: We performed a systematic review to determine whether MIS PLIF or open PLIF results in (1) better perioperative parameters, including blood loss, operative times, and length of hospital stay; (2) improved patient-reported outcome scores; and (3) improved disc distraction and (4) frequency of reoperation and complications when compared with open PLIF procedures. METHODS: A literature search of the MEDLINE database identified seven studies that met our inclusion criteria. A total of seven articles were included; quality was assessed using the Methodological Index for Non-Randomised Studies (MINORS) scale. Descriptive statistics were used to describe the included articles. RESULTS: In most studies, MIS PLIF was associated with decreased blood loss and shorter hospital stay but longer operative times. MIS PLIF resulted in better patient-related outcomes when compared with open PLIF in two studies in the short term, but most of the studies in this review found no short-term differences, and there was no difference at long-term followup in any studies. There was no significant difference in disc distraction. Both techniques appeared to have similar complication rates and reoperation rates. CONCLUSIONS: Based on the available evidence, which we restricted to prospective and retrospective studies with control groups, but did not include any well-designed randomized trials, MIS PLIF might lead to better perioperative parameters, but there was little evidence for improved patient-reported outcomes in the MIS groups. Randomized controlled trials are needed to compare these two surgical techniques.

Mechanical properties of bioresorbable self-reinforced posterior cervical rods.

STUDY DESIGN: A biomechanical study. OBJECTIVE: To test the mechanical and physical properties of self-reinforced copolymer bioresorbable posterior cervical rods and compare their mechanical properties to commonly used Irene titanium alloy rods. SUMMARY OF BACKGROUND DATA: Bioresorbable instrumentation is becoming increasingly common in surgical spine procedures. Compared with metallic implants, bioresorbable implants are gradually reabsorbed as the bone heals, transferring the load from the instrumentation to bone, eliminating the need for hardware removal. In addition, bioresorbable implants produce less stress shielding due to a more physiological modulus of elasticity. METHODS: Three types of rods were used: (1) 5.5 mm copolymer rods and (2) 3.5 mm and (3) 5.5 mm titanium alloy rods. Four tests were used on each rod: (1) 3-point bending test, (2) 4-point bending test, (3) shear test, and (4) differential scanning calorimeter test. The outcomes were recorded: Young modulus (E), stiffness, maximum load, deflection at maximum load, load at 1.0% strain of the rod's outer surface, and maximum bending stress. RESULTS: The Young modulus (E) for the copolymer rods (mean range, 6.4-6.8 GPa) was significantly lower than the 3.5 mm titanium rods (106 GPa) and the 5.5 mm titanium rods (95 GPa). The stiffness of the copolymer rods (mean range, 16.6-21.4 N/mm) was also significantly lower than the 3.5 mm titanium alloy rods (43.6 N/mm) and the 5.5 mm titanium alloy rods (239.6 N/mm). The mean maximum shear load of the copolymer rods was 2735 N and they had significantly lower mean maximum loads than the titanium rods. CONCLUSIONS: Copolymer rods have adequate shear resistance, but less load resistance and stiffness compared with titanium rods. Their stiffness is closer to that of bone, causing less stress shielding and better gradual dynamic loading. Their use in semirigid posterior stabilization of the cervical spine may be considered.

Is pelvic obliquity related to degenerative scoliosis?

OBJECTIVE: The hypothesis of this study is that pelvic obliquity (PO) is associated with specific patterns of degenerative scoliosis. METHODS: This study was a retrospective case series of consecutive patients undergoing fusion for lumbar conditions (degenerative scoliosis or spondylolisthesis). The discrepancy in the iliac crest height, coronal L1-S1 endplate angles, distance from L1 coronal bisector to the sacral center, number of degenerative scoliosis curves, and individual curve angulations were measured. RESULTS: Limb length discrepancy was present in 87% of patients with a degenerative scoliosis. There were 116 patients with a single curve > 5° and PO > 2 cm. Of the patients with a single curve, the apex of scoliosis was opposite the high iliac crest side in 79% patients. There were 338 patients with a double curve. The apex of scoliosis was opposite the high iliac crest side in 48% of patients. CONCLUSION: There were distinct patterns of limb length discrepancy corresponding to degenerative scoliotic curve morphology. In patients with single degenerative scoliotic curves, PO most commonly appeared to counteract the scoliotic curve and result in an overall decrease in trunk shift. This occurred because the high iliac crest was observed most commonly on the convex side of the scoliotic curve. This effect was not observed in double lumbar degenerative scoliotic curves.

Adjacent segment disease in the lumbar spine following different treatment interventions.

BACKGROUND CONTEXT: Adjacent segment disease (ASD) is symptomatic deterioration of spinal levels adjacent to the site of a previous fusion. A critical issue related to ASD is whether deterioration of spinal segments adjacent to a fusion is due to the spinal intervention or due to the natural history of spinal degenerative disease. PURPOSE: The purpose of this review is to summarize the recent clinical literature on adjacent segment disease in light of the natural history, patient-modifiable risk factors, surgical risk factors, sagittal balance, and new technology. STUDY DESIGN: This review will evaluate the recent literature on genetic and hereditary components of spinal degenerative disease and potential links to the development of ASD. METHODS: After a meticulous search of Medline for relevant articles pertaining to our review, we summarized the recent literature on the rate of ASD and the effect of various interventions, including motion preservation, sagittal imbalance, arthroplasty, and minimally invasive surgery. RESULTS: The reported rate of ASD after decompression and stabilization procedures is approximately 2% to 3% per year. The factors that are consistently associated with adjacent segment disease include laminectomy adjacent to a fusion and a sagittal imbalance. CONCLUSIONS: Spinal surgical interventions have been associated with ASD. However, whether such interventions may lead to an acceleration of the natural history of the disease remains questionable.

Neurological deficit due to cement extravasation following a vertebral augmentation procedure.

The authors endeavor to highlight the surgical management of severe neurological deficit resulting from cement leakage after percutaneous vertebroplasty and to systematically review the literature on the management of this complication. A patient presented after a vertebroplasty procedure for traumatic injury. A CT scan showed polymethylmethacrylate leakage into the right foramina at T-11 and L-1 and associated central stenosis at L-1. He underwent decompression and fusion for removal of cement and stabilization of the fracture segment. In the authors' systematic review, they searched Medline, Scopus, and Cochrane databases to determine the overall number of reported cases of neurological deficit after cement leakage, and they collected data on symptom onset, clinical presentation, surgical management, and outcome. After surgery, despite neurological recovery postoperatively, the patient developed pneumonia and died 16 days after surgery. The literature review showed 21 cases of cement extravasation with neurological deficit. Ultimately, 15 patients had resolution of the postoperative deficit, 5 had limited change in neurological status, and 2 had no improvement. Cement augmentation procedures are relatively safe, but certain precautions should be taken to avoid such complications including high-resolution biplanar fluoroscopy, considering the use of a local anesthetic, and controlling the location of cement spread in relationship to the posterior vertebral body. Immediate surgical intervention with removal of cement provides good results with complete recovery in most cases.

Does C1 fracture displacement correlate with transverse ligament integrity?

OBJECTIVE: The Rule of Spence states that displacement of the C1 lateral masses by >6.9-8.1 mm suggests loss of transverse ligament integrity. The purpose of this study was to establish the thresholds of C1 displacement on CT scans that correspond to transverse ligament disruption. METHODS: Over four years, consecutive patients with acute C1 fractures with at least three fracture lines were analyzed. CT measurements and MRI were assessed by blinded observers for bony displacement in the axial (internal and external lateral mass separation), coronal and sagittal planes and transverse ligament integrity. RESULTS: Eighteen patients were studied. Mean CT bony measurements were as follows: internal border lateral mass separation (ILM) 23.3 ± 3.4 mm, external border lateral mass separation (ELM) 50.3 ± 4.3 mm, total C1 lateral mass overhang over the C2 superior process (LMO) 5.4 ± 1.3 mm. Twelve patients were identified as having intact transverse ligament and six had transverse ligament disruption. There was no difference in mean normalized ILM, ELM, or LMO between patients with or without transverse ligament integrity (P > 0.05). CONCLUSION: There was no correlation between bony displacement and transverse ligament integrity. CT scans post-injury may not show the position of maximal displacement. If there is clinical concern about a possible transverse ligament injury, MRI should be performed.

Civilian gunshot injuries of the spinal cord: a systematic review of the current literature.

BACKGROUND: The principles that guide management of spinal cord injury (SCI) derive from injury resulting from blunt trauma, not gunshot wounds. Civilian gunshot-induced spinal cord injury (CGSWSCI) is a common, potentially serious cause of neurological deficit; there is disagreement about whether the same approaches used for SCI caused by blunt-force trauma should apply to gunshot-induced SCI. QUESTIONS/PURPOSES: We reviewed the literature to answer the following questions regarding presentation and outcome of gunshot wound-induced SCI: (1) Are there differences in recovery prognosis between complete SCI and other patterns of SCI in CGSWSCI. (2) Does the use of steroids improve neurological recovery? (3) Does surgery to remove the bullet affect neurological recovery in CGSWSCI? (4) Does surgery result in an increased risk of complications of treatment? METHODS: We performed a systematic literature review of articles related to civilian gunshot injuries to the spine. Information relating to incidence, pattern of neurological injury, associated injuries, treatment, neurological outcome, and associated complications was extracted. Three independent reviewers assessed the strength of evidence present in the literature by examining quality, quantity, and consistency of results. RESULTS: A total of 15 articles met the predetermined inclusion criteria. Complete SCIs are associated with the worst functional recovery regardless of treatment. Steroids do not appear to have any added benefit in terms of restoring sensory and motor function. There appears to be some neurologic benefit to surgical decompression with intracanalicular bullet retrieval in patients with an incomplete lesion and a cauda equina syndrome. Complication rates are greater in operated patients. CONCLUSIONS: These findings should be interpreted with caution because of considerable heterogeneity among the studies in the literature on gunshot-induced SCI and because of generally poor-quality study design and a high associated risk of selection bias. Supportive management should be the primary method of care, whereas surgery should be an option in case of radiographic evidence of a static compression on the spinal cord. Future studies are necessary to develop better treatment guidelines for patients with gunshot wound-associated SCI.

What is the incidence of dysphagia after posterior cervical surgery?

STUDY DESIGN: Prospective comparative study. OBJECTIVE: To determine whether dysphagia is a unique complication of anterior neck dissection or whether it occurs after any cervical surgery. SUMMARY OF BACKGROUND DATA: Dysphagia is a common complication after anterior cervical discectomy and fusion. However, current literature is scarce whether dysphagia occurs as a direct result of the anterior approach (dissection or instrumentation) or because of cervical spine surgery itself. METHODS: Patients undergoing posterior cervical surgery were prospectively evaluated for dysphagia up to 6 months after surgery. Patients were evaluated for dysphagia preoperatively, at 2 weeks and 6 weeks postoperatively using the dysphagia numeric rating scale. The data was compared with a previously published cohort of anterior cervical and lumbar surgical procedures from the same institution. Statistical significance was evaluated using the Fisher exact test. RESULTS: Eighty-five patients were included who underwent posterior cervical surgery. Baseline dysphagia was present in 11% (10/85) of patients. The incidence of new dysphagia was 10 of 85 (11%) at 2 weeks, 8 of 85 (8%) at 6 weeks, 13 of 85 (13%) at 12 weeks, and 5 of 85 (6%) at 24 weeks. The incidence of new dysphagia was significantly less than that of anterior cervical surgery at 2 weeks (posterior [P] 11% vs. anterior [A] 61.5%, P = 0.0001), 6 weeks (P 8% vs. A 44%, P = 0.0001), but not 12 weeks (P 13% vs. A 11%, P = 1). The incidence of dysphagia after posterior cervical surgery was significantly increased compared with that of lumbar surgery at 2 weeks (P 11% vs. lumbar surgery [L] 9%, P = 0.78), 6 weeks (P 8% vs. L 0%, P = 0.02), and 12 weeks (P 13% vs. L 0%, P = 0.007). At 12 weeks postoperatively, there was a statistically significant increase in postoperative neck pain (P = 0.008), tightness (P = 0.032), and peripheral pain/numbness (P = 0.032) in patients with dysphagia. CONCLUSION: Both anterior and posterior cervical surgery may result in long-term dysphagia in a small number of patients, perhaps due to loss of motion or postoperative pain. Surgeons should counsel their patients about possibility for dysphagia prior to all cervical spine surgery.

Preoperative risk stratification reduces the incidence of perioperative complications after total knee arthroplasty.

The purpose of this study was to validate a screening and management protocol to identify and reduce risk of renal, pulmonary, and delirium complications. A cohort study comparing incidence of perioperative complications on a consecutive series of patients undergoing total knee arthroplasty with a historical control group was conducted. The study cohort was evaluated prospectively to identify and reduce noncardiac medical complications. Medical records were reviewed for in-hospital complications. There were 623 patients in the study cohort and 493 patients in the control population. There was a statistically significant decrease in the incidence of delirium (control, 10.4% vs study, 0.8%; P = .0001), renal (4.9% vs 0.6%, P = .0001), cardiac (16.3% vs 2.1%, P = .0001), and pulmonary complications (5.7% vs 0.8%, P = .0001) in the screened patients vs control. Preoperative screening and management for medical complications resulted in a significant decrease in renal, pulmonary, delirium, and cardiac complications.

Management of cervical spine trauma: can a prognostic classification of injury determine clinical outcomes?

Although the management of cervical spine trauma is relatively complex, multiple classification systems have attempted to simplify it through the use of descriptive terms. Most historical classification systems failed to yield sufficient prognostic information to guide clinical treatment until the Subaxial Injury Classification system was developed. This classification system takes into account the injury morphology, discoligamentous complex, and the most important prognostic factor, neurologic status. The early results of this classification system have been encouraging and it is expected to improve spinal trauma care through enhancing more uniform nomenclature and communication for surgeons managing spinal trauma.