Laminotomy and transforaminal lumbar interbody fusion (TLIF) is usually used to treat unstable spinal stenosis. Minimally invasive surgery (MIS) can cause less muscle injury than conventional open surgery (COS). The purpose of this study was to compare the degree of postoperative fatty degeneration in the paraspinal muscles and the spinal decompression between COS and MIS based on MRI. Forty-six patients received laminotomy and TLIF (21 COS, 25 MIS) from February 2016 to January 2017 were included in this study. Lumbar MRI was performed within 3 months before surgery and 1 year after surgery to compare muscle-fat-index (MFI) change of the paraspinal muscles and the dural sac cross-sectional area (DSCAS) change. The average MFI change at L2–S1 erector spinae muscle was significantly greater in the COS group (27.37 ± 21.37% vs. 14.13 ± 19.19%, P = 0.044). A significant MFI change difference between the COS and MIS group was also found in the erector spinae muscle at the caudal adjacent level (54.47 ± 37.95% vs. 23.60 ± 31.59%, P = 0.016). DSCSA improvement was significantly greater in the COS group (128.15 ± 39.83 mm² vs. 78.15 ± 38.5 mm², P = 0.0005). COS is associated with more prominent fatty degeneration of the paraspinal muscles. Statically significant post-operative MFI change was only noted in erector spinae muscle at caudal adjacent level and L2–S1 mean global level. COS produces a greater area of decompression on follow up MRI than MIS with no statistical significance on clinical grounds.

Wnt signaling plays an important role in development and maintenance of many organs and tissues. The most-studied secreted Wnt inhibitors are sclerostin (SOST), Dickkopf-related protein 1 (DKK-1), and secreted frizzled related protein 1 (SFRP-1) which play important roles in bone turnover. The present study investigated the relationship between serum Wnt inhibitors and diseases with excessive ossification structures, such as ossification of posterior longitudinal ligament (OPLL), ankylosing spondylitis (AS), diffuse idiopathic skeletal hyperostosis (DISH), and ossification of yellow ligament (OYL). Twenty-five patients with AS, DISH, OPLL, or OYL were recruited in this study. Fasting peripheral blood samples were collected from all patients and nine controls. Various biomarkers of bone turnover including osteocalcin (OSC), osteoprotegerin (OPG), SFRP-1, DKK-1, and SOST were investigated. Our data showed that serum levels of OSC were higher, but Dkk-1 levels were lower in AS, DISH, OPLL, and OYL patients than those in the controls. Serum levels of SFRP-1 were significantly higher in DISH patients than those in the controls. Serum levels of SOST were significantly higher in DISH and OPLL patients than both levels in the controls. Serum levels of OPG were lower in AS patients than those in the controls. Serum levels of OSC were higher in the OPLL patients than those in the AS patients. Serum levels of DKK-1, SFRP-1, SOST, and OPG were not significantly different between the different disease groups. In this exploratory study, both OSC and DKK-1 levels are correlated with the clinical conditions associated with excessive ossification, indicating that blood OSC and DKK-1 levels may serve as diagnostic biomarkers for AS, DISH, OPLL, and OYL. These findings may also help discover potential drug therapies for management of these diseases in the future.

Percutaneous pedicle screw instrumentation is a minimally invasive surgical technique; however, the effects of using percutaneous pedicle screw fixation in treating patients with spinal infections have not yet been well demonstrated. The aim of this study, therefore, was to determine whether percutaneous posterior pedicle screw instrumentation is superior to the traditional open approach in treating pyogenic spondylodiscitis. We retrospectively reviewed data for 45 patients treated for pyogenic spondylodiscitis with anterior debridement and interbody fusion followed by a second-stage procedure involving either traditional open posterior pedicle screw fixation or percutaneous posterior pedicle screw fixation. Twenty patients underwent percutaneous fixation and 25 patients underwent open fixation. Demographic, operative, and perioperative data were collected and analyzed. The average operative time for the percutaneous procedure was 102.5 minutes, while the average time for the open procedure was 129 minutes. The average blood loss for the percutaneous patients was 89 ml versus a 344.8 ml average for the patients in the open group. Patients who underwent the minimally invasive surgery had lower visual analogue scale scores and required significantly less analgesia afterwards. After two years of follow-up, neither recurrent infection nor intraoperative complications, such as wound infection or screw loosening, were found in the percutaneous group. Moreover, there was no significant difference in outcome between the two groups in terms of Oswestry Disability Index scores. Anterior debridement and interbody fusion with bone grafting followed by minimally invasive percutaneous posterior instrumentation is an alternative treatment for pyogenic spondylodiscitis which can result in less intraoperative blood loss, shorter operative time, and reduced postoperative pain with no adverse effect on infection control.

Most guidelines recommend 6 to 12 weeks of parenteral antibiotic treatment for pyogenic spondylodiscitis. When surgical debridement is adequately performed, further intravenous antibiotic treatment duration can be reduced than that of conservative treatment alone theoretically. However, the appropriate duration of post-surgical parenteral antibiotic treatment is still unknown. This study aimed to identify the risk factors of recurrence and evaluate the appropriate duration after surgical intervention. This 3-year retrospective review included 102 consecutive patients who were diagnosed with pyogenic spondylodiscitis and underwent surgical intervention. Recurrence was defined as recurrent signs and symptoms and the need for another unplanned parenteral antibiotic treatment or operation within one year. This study included two major portions. First, independent risk factors for recurrence were identified by multivariable analysis, using the database of demographic information, pre-operative clinical signs and symptoms, underlying illness, radiographic findings, laboratory tests, intraoperative culture results, and treatment. Patients with any one of the risk factors were considered high-risk; those with no risk factors were considered low-risk. Recurrence rates after short-term (≤3 weeks) and long-term (> 3 weeks) parenteral antibiotic treatment were compared between the groups. Positive blood culture and paraspinal abscesses were identified as independent risk factors of recurrence. Accordingly, 59 (57.8%) patients were classified as low-risk and 43 (42.2%) as high-risk. Among the high-risk patients, a significantly higher recurrence rate occurred with short-term than with long-term antibiotic therapy (56.2% vs. 22.2%, p = 0.027). For the low-risk patients, there was no significant difference between short-term and long-term antibiotic therapy (16.0% vs. 20.6%, p = 0.461). The appropriate duration of parenteral antibiotic treatment in patients with pyogenic spondylodiscitis after surgical intervention could be guided by the risk factors. The duration of postoperative intravenous antibiotic therapy could be reduced to 3 weeks for patients without positive blood culture or abscess formation.