Impact of Individual Spinopelvic Anatomy on the Localization and Severity of Symptomatic Isthmic Spondylolisthesis.

STUDY DESIGN: Retrospective analysis of prospectively collected data. OBJECTIVES: Isthmic spondylolisthesis (iSPL) occurs most commonly in L5/S1 and L4/5. This study investigates the association between spinopelvic anatomy and the pathogenesis of iSPL. METHODS: Spinopelvic parameters as well as severity of slip grade were measured in sagittal spine radiographs of symptomatic patients with iSPL in segments L4/5 and L5/S1. Means were calculated and differences between both groups were analyzed. A correlation between the analyzed parameters and degree of slippage was performed. RESULTS: We included 73 subjects in this study; 11 in L4/5 group and 62 in L5/S1 group. Pelvic anatomy significantly differed between L4/5 and L5/S1 iSPL (Pelvic Incidence (PI) 54.8° vs 66.3°, P value = .006; Pelvic Radius (PR) 124.4 mm vs 137.4 mm; P value = .005 and Sacral Table Angle (STA) 101.0° vs 92.2°, P value < .001). The relative degree of slippage was significantly higher in the L5/S1 group (L4/5 29.1% vs L5/S1 40.1%, P value .022). We also observed a significant correlation between pelvic anatomy and the severity of the slip in iSPL at the L5/S1 level. CONCLUSIONS: Pelvic parameters PI and STA play an important role concerning the level of occurrence and severity of iSPL. Spinopelvic anatomy determines the pathogenesis of iSPL.

Intraoperative blood loss as indicated by haemoglobin trend is a predictor for the development of postoperative spinal implant infection-a matched-pair analysis.

BACKGROUND: With a reported rate of 0.7-20%, postoperative spinal implant infection (PSII) is one of the most common complications after spine surgery. While in arthroplasty both haematoma formation and perioperative blood loss have been identified as risk factors for developing periprosthetic joint infections and preoperative anaemia has been associated with increased complication rates, literature on the aetiology of PSII remains limited. METHODS: We performed a matched-pair analysis of perioperative haemoglobin (Hb) and haematocrit (Hct) levels in aseptic and septic spine revision surgeries. 317 patients were included, 94 of which were classified as septic according to previously defined criteria. Patients were matched according to age, body mass index, diabetes, American Society of Anesthesiologists score and smoking habits. Descriptive summaries for septic and aseptic groups were analysed using Pearson chi-squared for categorical or Student t test for continuous variables. RESULTS: Fifty patients were matched and did not differ significantly in their reason for revision, mean length of hospital stay, blood transfusion, operating time, or number of levels operated on. While there was no significant difference in preoperative Hb or Hct levels, the mean difference between pre- and postoperative Hb was higher in the septic group (3.45 ± 1.25 vs. 2.82 ± 1.48 g/dL, p = 0.034). CONCLUSIONS: We therefore show that the intraoperative Hb-trend is a predictor for the development of PSII independent of the amount of blood transfusions, operation time, number of spinal levels operated on and hospital length of stay, which is why strategies to reduce intraoperative blood loss in spine surgery need to be further studied.

Low sensitivity of histopathological examination of peri-implant tissue samples in diagnosing postoperative spinal implant infection.

AIMS: To evaluate the histopathological examination of peri-implant tissue samples as a technique in the diagnosis of postoperative spinal implant infection (PSII). METHODS: This was a retrospective analysis. Patients who underwent revision spinal surgery at our institution were recruited for this study. PSII was diagnosed by clinical signs, histopathology, and microbiological examination of intraoperatively collected samples. Histopathology was defined as the gold standard. The sensitivity for histopathology was calculated. A total of 47 patients with PSII and at least one microbiological and histopathological sample were included in the study. RESULTS: PSII occurred in approximately 28% of the study population. Histopathology showed a sensitivity of 51.1% in the diagnosis of PSII. The most commonly found pathogens were Cutibacterium acnes and gram-positive staphylococci. CONCLUSION: Histopathology has low sensitivity for detecting PSII. In particular, infections caused by low-virulence microorganisms are insufficiently detected by histopathology. Cite this article: Bone Joint J 2020;102-B(7):899-903.

Kyphoplasty Restores the Global Sagittal Balance of the Spine Independently from Pain Reduction.

Kyphoplasty is the standard surgical treatment of vertebral compression fractures. We aimed to clarify the influence of kyphoplasty on the sagittal profile as well as the relation between posture improvement and pain relief. For this purpose, we evaluated various radiological parameters of the sagittal profile on whole spine standing radiographs of 73 Patients with a single vertebral fracture treated by kyphoplasty. The key outcome was the postoperative change of the sagittal vertical axis (SVA). Additionally, clinical parameters including pain scores on visual analogue scale (VAS) and use of analgesics were obtained from medical records. Pre- and postoperative radiological as well as clinical parameters were compared. Additionally, the correlation between changes of SVA and changes of local kyphotic angle (LKA) or VAS was examined. The clinical parameters as well as various radiographic parameters (SVA, LKA, Gardner, Cobb) improved significantly postoperatively. The improvement of SVA correlated significantly with the correction of the LKA but not with postoperative pain relief. We conclude that kyphoplasty helps to restore the global sagittal balance of the spine after vertebral fractures. The correction of the sagittal profile seems to depend on the correction of the local kyphotic angle but does not correlate with postoperative pain relief.

Influence of operative timing on the early post-operative radiological and clinical outcome after kyphoplasty.

PURPOSE: To clarify the relationship between operative timing and the early post-operative radiological and clinical outcome after kyphoplasty. METHODS: We conducted a retrospective cohort study including patients who underwent kyphoplasty of a single vertebra. Patients were divided into three groups (acute [< 2 weeks], subacute [2-6 weeks] or chronic [6-51 weeks]) based on the interval between fracture and surgery. The relative vertebral body height (VBH) and local kyphotic angle (LKA) of the fractured vertebra (measured on plain radiographs) as well as pain and use of analgesics were compared pre- and post-operatively (day 2) and between the groups. RESULTS: A total of 230 patients (100 with acute, 91 with subacute and 39 with chronic fractures) with fractures from T4 to L5 were included. In all groups, there was a significant post-operative improvement in the anterior (8.9-12.9%) and middle (10.7-13.4%) VBH (all groups: p < 0.001), LKA (acute: 3.8°, p < 0.001; subacute: 4.3°, p < 0.001; chronic: 1.7°, p = 0.046) and pain. The use of analgesics significantly decreased post-operatively in the acute and subacute groups, but did not significantly change in the chronic group. Patients from acute (p = 0.042) and subacute (p = 0.027) groups showed significantly better post-operative correction of the LKA than the chronic group. CONCLUSION: Kyphoplasty is effective for vertebral height restoration as well as pain relief for both acute, subacute and chronic fractures. However, the achievable correction of the fracture-related local kyphosis decreases significantly after 6 weeks. Therefore, we recommend making a final decision about conservative vs. operative treatment within 6 weeks to ensure better height restoration in surgically treated patients.

Clinical presentation and diagnosis of acute postoperative spinal implant infection (PSII).

Acute postoperative infections after surgical interventions on the spinal column are associated with prolonged treatment duration, poor patient outcomes, and a high socioeconomic burden. In the field of joint replacement, guidelines have been established with recommendations for the diagnosis and treatment of such complications, but in spinal surgery there are no definitions permitting distinction between early and late infections and no specific instructions for their management. Various factors increase the risk of acute postoperative infection, including blood transfusions, leakage of cerebrospinal fluid, urinary tract infection, injury of the dura mater, an American Society of Anesthesiologists (ASA) score >2, obesity, diabetes mellitus, and surgical revision. We suggest defining all infections occurring within the first 4 weeks after spinal surgery as early infections. The symptoms are pain at rest, on motion, and/or pressure pain, abnormal warmth, local erythema, circumscribed swelling of the wound, and newly occurring secretion. Together with laboratory parameters such as C-reactive protein (CRP) and leukocytes, a central role is played by imaging in the form of magnetic resonance imaging (MRI), although diagnosis can be hampered by the presence of postoperative fluid collections such as edema or hematoma or by artifacts from an implant. Once an infection has been confirmed, immediate wound revision with debridement and rinsing (sodium hypochlorite) is essential. Intraoperatively it may prove advantageous to use jet lavage and administer vancomycin. We recommend leaving the implant in place in cases of acute postoperative infection. Patients who are not conditional for surgery can first receive antibiotic suppression treatment before surgery at a later date. In such cases initial computed tomography (CT)-guided aspiration or drain insertion can take place.

Antibiotic treatment of postoperative spinal implant infections.

Postoperative spinal implant infection (PSII) is a serious complication after spinal surgery. It is associated with increased morbidity and mortality for affected patients as well as significant costs for the healthcare system. Due to the formation of biofilm on foreign material, both diagnosis and treatment of PSII can pose a considerable challenge. Modern treatment protocols allow efficient eradication and good clinical outcomes in the majority of patients. In this article, we review the current antibiotic treatment concepts for PSII including the correct choice of antibiotics and their combination. In cases of late-onset PSII where the implants can be removed, two weeks of intravenous (IV) antibiotics followed by 4 weeks of oral antibiotics seem appropriate. If the implant needs to be retained, a 2-week IV antibiotic treatment should be followed by 10 weeks of oral antibiotic therapy with biofilm activity or, in case of problematic pathogens, a long-term suppression therapy. Initial empiric antibiotic therapy should cover staphylococci, streptococci, enterococci and Gram-negative bacilli as the most common pathogens. Antibiotic adjustments according to the type of pathogen and its antimicrobial susceptibility are essential for successful eradication of infection.

Comprehensive treatment algorithm of postoperative spinal implant infection.

Postoperative spinal implant infection (PSII) is a commonly found and serious complication after instrumented spinal surgery. Whereas early-onset PSII usually can be diagnosed by clinical symptoms, the diagnosis of late-onset PSII can be often made only by examination of intraoperatively collected samples. The treatment of PSII consists of surgical and antibiotic therapy schemes. In case of early PSII, the retention of spinal implants is a feasible option, whereas late PSII is usually treated by one-staged exchange of the spinal implants. Radical debridement of surrounding tissue should be performed in any case of PSII. The antibiotic treatment depends on either the implants can be removed or need to be retained or exchanged, respectively. If the causative pathogens are sensitive for biofilm-active antibiotic agents, the duration of antibiotic treatment amounts to 12 weeks with retention of spinal implants. In case of problematic pathogens, the application of antibiotics needs to be prolonged for an individual duration. Antibiotic treatment should always be initiated with an intravenous application for at least 2 weeks.

C-reactive protein misdiagnoses delayed postoperative spinal implant infections in patients with low-virulent microorganisms.

PURPOSE: C-reactive protein (CRP) has been shown to be a powerful parameter for detecting acute postoperative spinal implant infections (PSII) with a high sensitivity and specificity. However, little data are available on the performance of CRP in the diagnosis of delayed PSII. The aim of the current study was therefore to establish cutoff values for diagnosing delayed infection based on serum CRP. METHODS: All patients who underwent a revision surgery after instrumented spinal fusion from January 2013 through January 2016 were included. Demographic data, laboratory values, type of infection (including microbiological and pathological results), comorbidities and clinical manifestation were collected. The European Bone and Joint Infection Society criteria, proposed to diagnose periprosthetic joint infection, were used to diagnose PSII. RESULTS: A total of 257 patients were included. PSII was diagnosed in 61 patients, representing 24% of the study cohort. There was a significant difference in serum CRP levels between septic and aseptic cohorts (19.3 vs. 4.8 mg/l, p < 0.001). However, 26 patients (43%) from the PSII group had a normal (< 5 mg/l) serum CRP level prior to revision surgery. According to the ROC curve, a serum CRP threshold of 4.05 mg/l had a sensitivity of 64% and specificity of 68%. The most common isolated microorganism was Propionibacterium spp. followed by coagulase-negative staphylococci. CONCLUSION: Serum CRP showed low sensitivity and specificity for diagnosis of delayed PSII, even after applying cutoffs optimized by using receiver operating curve analysis, because of the high incidence of low-virulent pathogens. These slides can be retrieved under Electronic Supplementary Material.

Sonication of removed implants improves microbiological diagnosis of postoperative spinal infections.

PURPOSE: In total joint replacement, culturing of the sonication fluid of removed implants has proven to be more sensitive than conventional periprosthetic tissue culture for the microbiological diagnosis of prosthetic joint infection. However, its role in postoperative spinal implant infection (PSII) is not well investigated. Therefore, the aim of this study was to determine the validity of sonication in detecting infection following instrumented spine surgery. METHODS: In this prospective controlled consecutive cohort study, patients undergoing spinal revision between September 2016 and March 2018 were analyzed. In all patients sonication of removed spinal implants and at least one peri-implant tissue culture were performed. Demographic data, including age, gender, clinical manifestation, comorbidities, laboratory values (CRP and blood leukocytes), were recorded. Microorganisms causing PSII were documented. Sensitivity and specificity of sonication and peri-implant tissue culture were evaluated. RESULTS: A total of 118 patients were included. PSII was diagnosed in 35 patients, representing 29.6% of the study cohort. Sensitivities of tissue and sonication fluid culture were 65.7% (95% confidence interval (CI) 48.6-80.0) and 94.3% (95% CI 85.7-100) (p value = 0.002) and specificities 96.4% (95% CI 91.6-100) and 98.8% (95% CI 96.4-100), respectively. The most common microorganisms found in PSII were coagulase-negative Staphylococci and Propionibacterium acnes. Eleven PSIIs were detected only by sonicate fluid culture. CONCLUSIONS: Culture of samples obtained by spinal implant sonication was more sensitive than conventional peri-implant tissue culture for the microbiological diagnosis of PSII. Therefore, sonication should be used as a routine tool in the diagnostic workup of PSII. These slides can be retrieved under Electronic Supplementary Material.