Gursukhman S. Sidhu

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.

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.

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. Level of Evidence: 2

Operative and Nonoperative Treatment Approaches for Lumbar Degenerative Disc Disease Have Similar Long-Term Clinical Outcomes Among Patients with Positive Discography

OBJECTIVE It remains unclear whether fusion for lumbar degenerative disc disease with positive discography produces better outcomes compared with nonoperative treatment. The aim of this study was to compare outcomes of patients with discography-concordant lumbar degenerative disc disease electing for fusion versus nonoperative treatment. METHODS We retrospectively reviewed consecutive patients with back pain and concordant lumbar discogram who were offered fusion. Follow-up questionnaires included pain score, Oswestry disability index, short form-12, and satisfaction scale. Patients were stratified based on whether they elected for fusion or nonoperative treatment. RESULTS Overall follow-up was 48% (96/200). Patients lacking follow-up were slightly older (P = 0.021) and less likely to be smokers (P = 0.013). Between patients with and without follow-up, there were no significant differences in pain score at initial visit, body mass index, or gender (P ≥ 0.40). The 96 patients for whom follow-up was obtained included 53 in the operative and 43 in the nonoperative groups. At baseline, there were no significant differences between these groups based on age, pain score, body mass index, smoking, or gender (P ≥ 0.25). Mean follow-up was 63 months for operative and 58 months for nonoperative patients (P = 0.20). The mean pain score at last follow-up improved significantly for operative and nonoperative patients (P < 0.001). At follow-up, operative and nonoperative groups did not differ significantly with regard to pain scores, Oswestry disability index, short form-12, or satisfaction scale. CONCLUSIONS Comparison of long-term outcomes for patients with back pain and concordant discography did not demonstrate a significant difference in outcome measures of pain, health status, satisfaction, or disability based on whether the patient elected for fusion or nonoperative treatment.

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.

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.

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 &khgr;2 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.

Change in Angular Alignment is Associated With Early Dysphagia After Anterior Cervical Diskectomy 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.

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.

The Efficacy of Manual Axially Loaded Magnetic Resonance Imaging in Diagnosing Potential Thoracolumbar Osteoporotic Fracture Instability: A Case Report

A 68 year old female who had occult instability at a symptomatic osteoporotic L1 burst fracture was diagnosed by manual axially loaded magnetic resonance imaging. Traction resulted in the reduction of the fracture and decompression of the conus. Based on these findings, the patient underwent L1-L2 fusion with complete resolution of her back and leg pain. Our objective is to describe the utility of such imaging in detecting an occult lumbar instability. This study suggests that a manual axially loaded compression-traction magnetic resonance image may be an efficacious diagnosis option in patients with persistent symptoms treated non-operatively.