Implantable Pulse Generator Site May Be Associated With Spinal Cord Stimulation Revision Surgeries

BackgroundThe use of implantable pulse generators (IPG) for spinal cord stimulation (SCS) in patients with chronic pain has been well established. Although IPG-related complications have been reported on, the association between IPG site and SCS complications has not been well studied.ObjectiveTo investigate whether IPG placement site in buttock or flank is associated with SCS complications and, hence, revision surgeries.MethodA retrospective cohort study was performed that included 330 patients (52% female) treated at a single institution who underwent permanent implantation of an SCS system between 2014 and 2018. Patients ranged between 20 and 94 years of age (mean: 57.54 ± 13.25). Statistical analyses were conducted using IBM SPSS Statistics. Tests included independent samples t test, chi-square test, Mann–Whitney U test, Spearman’s rank correlation coefficient, and logistic regression.ResultsThere was a total of 93 revision surgeries (rate of 28%), where 71 out of 330 patients (rate of 21.5%) had had at least one revision surgery. Univariate tests demonstrated a significant association between IPG site and revision surgeries (p = 0.028 [chi-square test] and p = 0.031 [Mann–Whitney U test]); however, multivariate logistic regression demonstrated that neither IPG site was more likely than the other to require revision surgeries (p = 0.286).ConclusionAlthough this study found a significant association between IPG site and revision surgeries, the effect of IPG site was not found to be predictive. The IPG site likely influences whether a patient will require revision surgery, but further investigation is required to establish this association.     

Motor dysfunction in mild cognitive impairment as tested by kinematic analysis and transcranial magnetic stimulation

ObjectivePrevious studies have demonstrated voluntary movement alterations as well as motor cortex excitability and plasticity changes in patients with mild cognitive impairment (MCI). To investigate the pathophysiology of movement abnormalities in MCI, we tested possible relationships between movement abnormalities and primary motor cortex alterations in patients.MethodsFourteen amnestic MCI (aMCI) patients and 16 healthy controls were studied. Cognitive assessment was performed using clinical scales. Finger tapping was recorded by a motion analysis system. Transcranial magnetic stimulation was used to test the input/output curve of motor evoked potentials, intracortical inhibition, and short-latency afferent inhibition. Primary motor cortex plasticity was probed by theta burst stimulation. We investigated correlations between movement abnormalities, clinical scores, and cortical neurophysiological parameters.ResultsMCI patients showed less rhythmic movement but no other movement abnormalities. Cortical excitability measures were normal in patients, whereas plasticity was reduced. Movement rhythm abnormalities correlated with frontal dysfunction scores.ConclusionOur study in MCI patients demonstrated abnormal voluntary movement and plasticity changes, with no correlation between the two. Altered rhythm correlated with frontal dysfunction.SignificanceOur results contribute to the understanding of pathophysiological mechanisms of motor impairment in MCI.     

Management of Chronically Infected Total Knee Arthroplasty With Severe Bone Loss Using Static Spacers With Intramedullary Rods

BackgroundTwo-stage revision with static antibiotic spacers is the preferred treatment for chronically infected total knee arthroplasty (TKA) associated with severe bone loss. Intramedullary rods to reinforce static spacers have been described. On those, however, bacterial colonization may occur and hamper infection control. This study reports the microbiological findings on the spacer rods and the treatment outcome among these patients.MethodsWe reviewed 97 infected TKA with extensive bone loss treated with antibiotic-loaded cement spacers reinforced with intramedullary rods. Mean interim period with the spacer in situ was 9 weeks (range: 6-24 weeks). Intraoperative cultures and sonicated spacer rods were analyzed. Mean follow-up after TKA reimplantation was 41 months (range: 27-56 months). Treatment success was defined using the modified Delphi consensus criteria.ResultsTwenty-two patients (23%) had treatment failure, including 3 reinfections caused by the same organism, 9 reinfections caused by a different organism, 9 patients required interim spacer exchange, and 1 patient died in the early postoperative course. Sonication cultures of the spacer rods were positive in 2 cases (2%), and none of them failed. Host and limb status was significantly worse in patients who sustained reinfection. At the latest follow-up, all patients had a TKA in place, and 2 patients received chronic antibiotic suppression.ConclusionTwo-stage revision with the use of intramedullary rods is a safe and efficient treatment for chronically infected TKA with severe bone loss. Most reinfections grew different organisms compared with initial infection. Compromised hosts and extremities may be subjected to chronic antibiotic suppression.     

Does Timing of Primary Total Hip Arthroplasty Prior to or After Lumbar Spine Fusion Have an Effect on Dislocation and Revision Rates?

Background

Patients undergoing primary total hip arthroplasty (THA) following lumbar spine fusion have an increased incidence of dislocation compared to those without prior lumbar fusion. The purpose of this study is to determine if timing of THA prior to or after lumbar fusion would have an effect on dislocation and revision incidence in patients with both hip and lumbar spine pathology.

Persistent Fistula for Treatment of a Failed Periprosthetic Joint Infection: Relic From the Past or a Viable Salvage Procedure?

BackgroundNew treatment algorithms for periprosthetic joint infections (PJIs) show high success rates in achieving permanent infection eradication with some degree of failure. Different salvage procedures are described, but there is no evidence for persistent fistula (PF). The purpose of this study was to analyze PF as a salvage procedure in patients with therapy-resistant PJIs.MethodsThis retrospective analysis included all patients treated with PF (2005-2018) in a maximum care center with PJI (knee or hip). The baseline parameters (age, sex, BMI) and other data (number of surgeries, pathogen spectrum, American Society of Anesthesiologists classification) were recorded. The function was documented using the Harris Hip Score, the Knee Society Score, and the quality of life using the SF-36 Health Survey.ResultsA total of 159 patients were included (80 ± 12 years) and subdivided into four groups: hip (n = 66), knee (n = 13), Girdlestone resection arthroplasty (n = 50), knee arthrodesis (n = 27). Patients stayed 111 ± 87 days in the hospital, underwent six operations and three revisions after establishing PF. The mean American Society of Anesthesiologists score was 2.7. The BMI was 31 ± 3 kg/m² (P = .1). The follow-up was 2.8 ± 0.5 years including 27 patients. The Harris Hip Score and Knee Society Score were 38 and 34, respectively. SF-36 showed no significant difference.ConclusionThe study showed poor outcomes regarding quality of life and the function of the infected joint. Therefore, the indication for establishing a PF in the treatment of PJI must be assessed very critically. PF is only an option for multimorbid patients with a limited life expectancy.     

Serum Fibrinogen Test Performs Well for the Diagnosis of Periprosthetic Joint Infection

BackgroundSerum fibrinogen (FIB) is an acute-phase glycoprotein in the infection response that may stop excessive bleeding. The purposes of this study are to determine the value of FIB that can be used to differentiate between periprosthetic joint infection (PJI) and aseptic loosening of the prosthesis, and to determine the clinical significance of FIB for analyzing infection outcomes after first-stage surgery.MethodsThis retrospective study included 90 patients undergoing total knee arthroplasty or total hip arthroplasty revision from January 2015 to August 2019. PJI was confirmed in 53 patients (group A), and the other 37 patients were diagnosed with aseptic loosening of the prosthesis (group B). Only 21 patients in group A documented the results for serum FIB, C-reactive protein (CRP), and erythrocyte sedimentation rate (ESR) after spacer insertion, so the postoperative serological marker levels of the these patients were also assessed.ResultsThe FIB, CRP, and ESR levels were significantly higher in group A than in group B (P < .001). The area under the receiver operating characteristic curve was highest for FIB at 0.928. Analyses of FIB levels revealed a sensitivity of 79.25% and a specificity of 94.59%. FIB levels were significantly lower in patients with PJI after spacer insertion (P < .001).ConclusionFIB is an adequate test to aid in diagnosing PJI, and it is not inferior to CRP and ESR in distinguishing between PJI and aseptic loosening of the prosthesis. It is an especially useful tool in assessing infection outcomes after first-stage surgery.