Use of NEedle Versus suRFACE Recording Electrodes for Detection of Intraoperative Motor Warnings: A Non-Inferiority Trial. The NERFACE Study Part II.

In the NERFACE study part I, the characteristics of muscle transcranial electrical stimulation motor evoked potentials (mTc-MEPs) recorded from the tibialis anterior (TA) muscles with surface and subcutaneous needle electrodes were compared. The aim of this study (NERFACE part II) was to investigate whether the use of surface electrodes was non-inferior to the use of subcutaneous needle electrodes in detecting mTc-MEP warnings during spinal cord monitoring. mTc-MEPs were simultaneously recorded from TA muscles with surface and subcutaneous needle electrodes. Monitoring outcomes (no warning, reversible warning, irreversible warning, complete loss of mTc-MEP amplitude) and neurological outcomes (no, transient, or permanent new motor deficits) were collected. The non-inferiority margin was 5%. In total, 210 (86.8%) out of 242 consecutive patients were included. There was a perfect agreement between both recording electrode types for the detection of mTc-MEP warnings. For both electrode types, the proportion of patients with a warning was 0.12 (25/210) (difference, 0.0% (one-sided 95% CI, 0.014)), indicating non-inferiority of the surface electrode. Moreover, reversible warnings for both electrode types were never followed by permanent new motor deficits, whereas among the 10 patients with irreversible warnings or complete loss of amplitude, more than half developed transient or permanent new motor deficits. In conclusion, the use of surface electrodes was non-inferior to the use of subcutaneous needle electrodes for the detection of mTc-MEP warnings recorded over the TA muscles.

Comparing Motor-Evoked Potential Characteristics of NEedle versus suRFACE Recording Electrodes during Spinal Cord Monitoring-The NERFACE Study Part I.

Muscle-recorded transcranial electrical stimulation motor-evoked potentials (mTc-MEPs) are used to assess the spinal cord integrity. They are commonly recorded with subcutaneous needle or surface electrodes, but the different characteristics of mTc-MEP signals recorded with the two types of electrodes have not been formally compared yet. In this study, mTc-MEPs were simultaneously recorded from the tibialis anterior (TA) muscles using surface and subcutaneous needle electrodes in 242 consecutive patients. Elicitability, motor thresholds, amplitude, area under the curve (AUC), signal-to-noise ratio (SNR), and the variability between mTc-MEP amplitudes were compared. Whereas amplitude and AUC were significantly higher in subcutaneous needle recordings (p < 0.01), motor thresholds and elicitability were similar for surface and subcutaneous needle recordings. Moreover, the SNRs were >2 in more than 99.5% of the surface and subcutaneous needle recordings, and the variability between consecutive amplitudes was not significantly different between the two recording electrode types (p = 0.34). Surface electrodes appear to be a good alternative to needle electrodes for spinal cord monitoring. They are non-invasive, can record signals at similar threshold intensities, have adequately high SNRs, and record signals with equivalent variability. Whether surface electrodes are non-inferior to subcutaneous needle electrodes in detecting motor warnings is investigated in part II of the NERFACE study.

Predictive Factors on Initial in-brace Correction in Idiopathic Scoliosis: A Systematic Review.

STUDY DESIGN: Systematic literature review. OBJECTIVE: The aim of this study was to systematically review the literature and provide an overview of reported predictive factors on initial in-brace correction in patients with idiopathic scoliosis (IS). SUMMARY OF BACKGROUND DATA: Brace therapy is the best proven non-surgical treatment for IS. There is strong evidence that lack of initial in-brace correction is associated with brace treatment failure. To improve initial in-brace corrections and subsequently long-term brace treatment success, knowledge about factors influencing initial in-brace correction is a prerequisite. METHODS: A systematic literature search was performed in Pubmed, Embase, Web-of-Science, Scopus, Cinahl, and Cochrane in November 2020. Studies which reported factors influencing initial in-brace correction in IS patients treated with brace therapy were considered eligible for inclusion. RESULTS: Of the 4562 potentially eligible articles identified, 28 studies fulfilled the inclusion criteria and were included in this systematic review. Nine studies (32%) were classified as high quality studies and the remaining 19 studies (68%) as low quality. Thirty-four different reported factors were collected from the included studies. Strong evidence was found for increased curve flexibility as favorable predictive factor for initial in-brace correction. Moderate evidence was found for thoracolumbar or lumbar curve pattern as favourable predictive factor, and double major curve pattern as unfavourable predictive factor for initial in-brace correction. Also moderate evidence was found that there is no significant difference on initial in-brace correction between computer-aided design and manufacturing systems (CAD/CAM) braces with or without finite element models (FEM) simulation, and braces fabricated using the conventional plaster-cast. CONCLUSION: The results of this systematic review indicate that increased curve flexibility is strongly associated with increased initial in-brace correction.Level of Evidence: 1.

In-Brace versus Out-of-Brace Protocol for Radiographic Follow-Up of Patients with Idiopathic Scoliosis: A Retrospective Study.

The purpose of this retrospective study was to compare two standardized protocols for radiological follow-up (in-brace versus out-of-brace radiographs) to study the rate of curve progression over time in surgically treated idiopathic scoliosis (IS) patients after failed brace treatment. In-brace radiographs have the advantage that proper fit of the brace and in-brace correction can be evaluated. However, detection of progression might theoretically be more difficult. Fifty-one IS patients that underwent surgical treatment after failed brace treatment were included. For 25 patients, follow-up radiographs were taken in-brace. For the other 26 patients, brace treatment was temporarily stopped before out-of-brace follow-up radiographs were taken. Both groups showed significant curve progression compared to baseline after a mean follow-up period of 3.4 years. The protocol with in-brace radiographs was noninferior regarding curve progression rate over time. The estimated monthly Cobb angle progression based on the mixed-effect model was 0.5 degrees in both groups. No interaction effect was found for time, and patients' baseline Cobb angle (p = 0.98), and for time and patients' initial in-brace correction (p = 0.32). The results of this study indicate that with both in-brace and out-of-brace protocols for radiographic follow-up, a similar rate of curve progression can be expected over time in IS patients with failed brace treatment.

Positional dyspnea and tracheal compression as indications for goiter resection.

HYPOTHESES: Goiter is a surgically reversible cause of positional dyspnea (PD). Substernal tracheal compression (TC) predicts PD relief after thyroidectomy (Tx). DESIGN: Retrospective analysis of a prospective structured management algorithm. SETTING: Endocrine surgery academic center. METHODS: Before Tx, 1081 patients were queried about PD. Those patients with substernal goiter underwent computed tomography, and their degree of TC was estimated as greatest percent reduction of transverse tracheal diameter. For 197 patients with PD, TC, or both, surgical outcomes were examined with a mean follow- up of 12.6 months. After Tx, patients who carried the diagnosis of obstructive sleep apnea were referred for repeat sleep study evaluation. RESULTS: Positional dyspnea was reported by 188 of 1081 patients, and after Tx the PD improved or resolved in 82.4%. In the 151 patients with substernal goiter, TC was present on imaging in 97.2%; the mean (range) TC was 34% (5%-90%). Patients with TC had a high likelihood of PD (93.5%). After substernal goiter resection, PD improved in stepwise association with total resected thyroid gland weight. Improvement in PD was strongly predicted by both gland weight of 100 g or more (P.001) and by TC of 35% or more (P.01). After Tx, 59 of 77 snorers (76.6%) reported improvement in snoring, 77.1% of patients with obstructive sleep apnea reported improved PD, and 2 of 3 retested patients with obstructive sleep apnea demonstrated objective improvement in sleep study apnea-hypopnea index. CONCLUSIONS: Resection of bulky goiter frequently improves PD, which in substernal goiter is highly associated with TC. Either PD or TC of 35% or more prompt Tx. Goiter should be considered when obstructive sleep apnea is diagnosed.

Histopathology of aspiration pneumonia not associated with food or other particulate matter: a clinicopathologic study of 10 cases diagnosed on biopsy.

Aspiration pneumonia most often presents in surgical lung biopsies as a granulomatous pneumonia with acute inflammation, microabscesses, and a granulomatous reaction to food or other particulate matter. In this study of 10 patients with clinical aspiration in whom surgical lung biopsy was performed, 3 additional patterns of lung injury were seen: organizing pneumonia (4 patients); acute diffuse alveolar damage (3 patients); and chronic bronchiolitis (3 patients), in whom 2 had evidence of extensive pleuropulmonary fibrosis and scarring. This study adds to the earlier described literature on granulomatous reactions to food and particulate matter in the lung by alerting pathologists to other histopathologic manifestations of aspiration-induced lung injury in surgical lung biopsies.

Comparable efficacies of the antimicrobial peptide human lactoferrin 1-11 and gentamicin in a chronic methicillin-resistant Staphylococcus aureus osteomyelitis model.

The therapeutic efficacy of an antimicrobial peptide, human lactoferrin 1-11 (hLF1-11), was investigated in a model of chronic methicillin-resistant Staphylococcus aureus (MRSA) (gentamicin susceptible) osteomyelitis in rabbits. We incorporated 50 mg hLF1-11/g or 50 mg gentamicin/g cement powder into a calcium phosphate bone cement (Ca-P) and injected it into the debrided tibial cavity, creating a local drug delivery system. The efficacy of hLF1-11 and gentamicin was compared to that of a sham-treated control (plain bone cement) (n=6) and no treatment (infected only) (n=5). The results were evaluated by microbiology, radiology, and histology. MRSA was recovered from all tibias in both control groups (n=11). On the other hand, hLF1-11 and gentamicin significantly reduced the bacterial load. Furthermore, no growth of bacteria was detected in five out of eight and six out of eight specimens of the hLF1-11- and gentamicin-treated groups, respectively. These results were confirmed by a significant reduction of the histological disease severity score by hLF1-11 and gentamicin compared to both control groups. The hLF1-11-treated group also had a significantly lower radiological score compared to the gentamicin-treated group. This study demonstrates the efficacy of hLF1-11 incorporated into Ca-P bone cement as a possible therapeutic strategy for the treatment of osteomyelitis, showing efficacy comparable to that of gentamicin. Therefore, the results of this study warrant further preclinical investigations into the possibilities of using hLF1-11 for the treatment of osteomyelitis.

In vivo comparison of Dhvar-5 and gentamicin in an MRSA osteomyelitis prevention model.

OBJECTIVES: The continued rise in drug-resistant pathogens has led to global research efforts into new antimicrobial agents. A promising class of new agents are the antimicrobial peptides. The aim of the study was to investigate the efficacy of the antimicrobial peptide Dhvar-5 in a prophylactic, methicillin-resistant Staphylococcus aureus (MRSA) osteomyelitis model. METHODS: Dhvar-5 (12 mg or 24 mg/rabbit) was incorporated into polymethyl methacrylate (PMMA) beads as a local drug delivery system. For comparison, plain beads (control) and beads containing gentamicin as a sulphate (10 mg or 24 mg per rabbit) were also prepared. The beads were inserted into the inoculated femoral cavity of 36 rabbits, and 1 week later they were killed. The presence and severity of MRSA osteomyelitis was assessed by culture and histology. RESULTS: Both the 24 mg Dhvar-5 beads and the 24 mg gentamicin sulphate beads significantly reduced the bacterial load of the inoculated femora compared with the control chain. Although a 24 mg Dhvar-5 dose inhibited MRSA growth, it did not completely sterilize the femora. Sterilization occurred only in some of the gentamicin-treated specimens. CONCLUSION: We conclude that both the gentamicin beads and the Dhvar-5 beads were only partially effective at preventing MRSA infection in this model.

Osteomyelitis prevention in rabbits using antimicrobial peptide hLF1-11- or gentamicin-containing calcium phosphate cement.

OBJECTIVES: The efficacy of prophylactic treatment with human lactoferrin 1-11 (hLF1-11), a broad-spectrum antimicrobial peptide, was studied in a rabbit model of femur infection. METHODS: Calcium phosphate cement with 50 mg/g hLF1-11 or gentamicin was injected into the femoral canal, after inoculation with Staphylococcus aureus. Three weeks later, slices of the proximal femora were sawn for quantitative bacterial culture and histology. RESULTS: Treatment with hLF1-11 (P<0.038) or gentamicin (P<0.008) caused a reduction of cfu compared with the untreated control rabbits. The number of sterile cultures was higher in hLF1-11- (3/7) and gentamicin- (5/6) treated animals than in controls (1/7). Radiological and histological analysis showed early bone ingrowth into the cement cracks, and only moderate pathological changes in rabbits with positive cultures. CONCLUSIONS: Local prophylaxis with hLF1-11 effectively reduced development of osteomyelitis in a rabbit model, but gentamicin resulted in a larger number of sterile femora.

Continuous-release or burst-release of the antimicrobial peptide human lactoferrin 1-11 (hLF1-11) from calcium phosphate bone substitutes.

OBJECTIVES: In order to identify possible drug delivery systems against resistant bone infection, we determined the release of the antimicrobial peptide (AMP) human lactoferrin 1-11 (hLF1-11) from commercially available bone substitutes. METHODS: We combined six calcium phosphate cements and six granule-types with 5 mg/g hLF1-11 and measured its availability and release in vitro from cements (7 days) and granules (3 days). The integrity and antimicrobial activity of the hLF1-11 that was released during the first 24 h were measured, using mass spectrometry, and a killing assay on methicillin-resistant Staphylococcus aureus (MRSA). RESULTS: Most of the cements showed burst release followed by low-level continuous release, whereas the coated granules showed high burst release for 24 h. After release the peptide was active (in nine of 12 materials) and intact. CONCLUSIONS: Different release profiles may be obtained by choosing the appropriate carrier, which supports the feasibility of biodegradable carriers releasing AMPs against resistant infections.