Influence of microbiological diagnosis on the clinical course of spondylodiscitis.

PURPOSE: This study sought to recognize differences in clinical disease manifestations of spondylodiscitis depending on the causative bacterial species. METHODS: We performed an evaluation of all spondylodiscitis cases in our clinic from 2013-2018. 211 patients were included, in whom a causative bacterial pathogen was identified in 80.6% (170/211). We collected the following data; disease complications, comorbidities, laboratory parameters, abscess occurrence, localization of the infection (cervical, thoracic, lumbar, disseminated), length of hospital stay and 30-day mortality rates depending on the causative bacterial species. Differences between bacterial detection in blood culture and intraoperative samples were also recorded. RESULTS: The detection rate of bacterial pathogens through intraoperative sampling was 66.3% and could be increased by the results of the blood cultures to a total of 80.6% (n = 170/211). S. aureus was the most frequently detected pathogen in blood culture and intraoperative specimens and and was isolated in a higher percentage cervically than in other locations of the spine. Bacteremic S. aureus infections were associated with an increased mortality (31.4% vs. overall mortality of 13.7%, p = 0.001), more frequently developing complications, such as shock, pneumonia, and myocardial infarction. Comorbidities, abscesses, length of stay, sex, and laboratory parameters all showed no differences depending on the bacterial species. CONCLUSION: Blood culture significantly improved the diagnostic yield, thus underscoring the need for a structured diagnostic approach. MSSA spondylodiscitis was associated with increased mortality and a higher incidence of complications.

Posterior vertebral column resection as a safe procedure leading to solid bone fusion in metastatic epidural spinal cord compression.

OBJECTIVE: Cancer is one of the leading causes of death and greatly decreases a patient's quality of life. Vertebral metastases often lead to epidural spinal cord compression (ESCC) requiring surgical therapy. It has previously been shown that in patients with metastatic ESCC (MESCC), a surgical intervention leads to an improved outcome. Although the treatment paradigms in spinal metastases have changed and separation surgery followed by stereotactic radiosurgery is considered the best strategy, there are still cases in which 360° decompression with stabilization is indicated. In these patients, a proper bone fusion should be the treatment goal to guarantee good clinical results in extended survival times through progressions in oncological therapies. The aim of this study was to examine the safety and feasibility of posterior vertebral column resection (pVCR) in everyday clinical practice, achievement of bone fusion, and midterm outcome in patients with MESCC. METHODS: All patients treated with pVCR due to MESCC between 2013 and 2020 were enrolled in this observational single-center study. Demographics, outcome parameters, numeric rating scale (NRS) score, Frankel grade, and Karnofsky Performance Scale (KPS) score were evaluated. Radiological images routinely acquired during follow-up were reviewed and screened for the presence of bone fusion. RESULTS: Sixty-six patients were treated by eight surgeons. The mean follow-up period was 549 ± 739 days. At baseline, the average age was 64.4 ± 10.9 years. Reported NRS scores (preoperative 6.2 ± 1.7 vs postoperative 3.4 ± 1.6) and segmental kyphosis as measured on sagittal CT images (preoperative 13.5° ± 8.6° vs postoperative 3.8° ± 5.4°) decreased significantly (p < 0.001). In only 2 patients (3%), the Frankel grade worsened postoperatively, whereas in 12 patients (18.2%) an improvement was documented. The KPS score remained constant during the observation period (preoperative 73.2% ± 18.2% vs 78.3% ± 18% at last follow-up). Bone fusion was observed in 26 patients (86.7%) receiving CT more than 100 days after the index surgery. CONCLUSIONS: pVCR is a reliable surgical technique in daily clinical practice, which proves to be beneficial in terms of short- as well as midterm outcome, as judged by the KPS and NRS. The overall improvement in the Frankel grade shows patient safety. A bone fusion was observed regularly in oncological patients undergoing pVCR. The authors therefore conclude that pVCR is a safe, fast, and efficient strategy to achieve stability and pain relief by achievement of bone fusion in cancer patients.

Intraoperative blood loss in oncological spine surgery.

OBJECTIVE: Intraoperative blood loss in patients undergoing oncological spine surgery poses a major challenge for vulnerable patients. The goal of this study was to assess how the surgical procedure, tumor type, and tumor anatomy, as well as anesthesiological parameters, affect intraoperative blood loss in oncological spine surgery and to use this information to generate a short preoperative checklist for spine surgeons and anesthesiologists to identify patients at risk for increased intraoperative blood loss. METHODS: The authors performed a retrospective analysis of 430 oncological patients who underwent spine surgery between 2013 and 2018 at the university medical spine center. Enrolled patients had metastatic tumor of the spine requiring surgical decompression of neural structures and/or stabilization including tumor biopsy using an open, percutaneous, and/or combined dorsoventral approach. Patients requiring vertebro- and kyphoplasty or biopsy only were excluded. Statistical analyses performed included a multiple linear regression analysis. RESULTS: The mean intraoperative blood loss in the study patient cohort was 1176 ± 1209 ml. In total, 33.8% of patients received intraoperative red blood cell transfusions. The statistical analyses showed that tumor histology indicating myeloma, operative procedure length, epidural spinal cord compression (ESCC) score, tumor localization, BMI, and surgical strategy were significantly associated with increased intraoperative blood loss or risk of needing allogeneic blood transfusions. Anesthesiological parameters such as the American Society of Anesthesiologists (ASA) Physical Status classification score were not associated with blood loss. Multiple linear regression analysis demonstrated good predictive value (r = 0.437) for a five-item preoperative checklist to identify patients at risk for high intraoperative blood loss. CONCLUSIONS: The analyses performed in this study demonstrated key factors affecting intraoperative blood loss and showed that a simple preoperative checklist including these factors can be used to identify patients undergoing surgery for metastatic spine tumors who are at risk for increased intraoperative blood loss. ABBREVIATIONS: ABT = allogeneic blood transfusion; ASA = American Society of Anesthesiologists; ESCC = epidural spinal cord compression; KW = Kruskal-Wallis; MET = metabolic equivalent of task; RBC = red blood cell.

Bacterial adhesion characteristics on implant materials for intervertebral cages: titanium or PEEK for spinal infections?

PURPOSE: Surgical intervention with intercorporal stabilisation in spinal infections is increasingly needed. Our aim was to compare titanium and polyetheretherketon (PEEK) cages according to their adhesion characteristics of different bacteria species in vitro. METHODS: Plates made from PEEK, polished titanium (Ti), two-surface-titanium (TiMe) (n = 2-3) and original PEEK and porous trabecular structured titanium (TiLi) interbody cages (n = 4) were inoculated in different bacterial solutions, S.aureus (MSSA, MRSA), S.epidermidis and E.coli. Growth characteristics were analysed. Biofilms and bacteria were visualised using confocal- and electron microscopy. RESULTS: Quantitative adherence of MSSA, MRSA, S.epidermidis and E.coli to Ti, TiMe and PEEK plates were different, with polished titanium being mainly advantageous over PEEK and TiMe with significantly less counts of colony forming units (CFU) for MRSA after 56 h compared to TiMe and at 72 h compared to PEEK (p = 0.04 and p = 0.005). For MSSA, more adherent bacteria were detected on PEEK than on TiMe at 32 h (p = 0.02). For PEEK and TiLi cages, significant differences were found after 8 and 72 h for S.epidermidis (p = 0.02 and p = 0.008) and after 72 h for MSSA (p = 0.002) with higher bacterial counts on PEEK, whereas E.coli showed more CFU on TiLi than PEEK (p = 0.05). Electron microscopy demonstrated enhanced adhesion in transition areas. CONCLUSION: For S.epidermidis, MSSA and MRSA PEEK cages showed a higher adherence in terms of CFU count, whereas for E.coli PEEK seemed to be advantageous. Electron microscopic visualisation shows that bacteria did not adhere at the titanium mesh structure, but at the border zones of polished material to rougher parts.

Carbon fiber-reinforced PEEK versus titanium implants: an in vitro comparison of susceptibility artifacts in CT and MR imaging.

Artifacts in computed tomography (CT) and magnetic resonance imaging (MRI) due to titanium implants in spine surgery are known to cause difficulties in follow-up imaging, radiation planning, and precise dose delivery in patients with spinal tumors. Carbon fiber-reinforced polyetheretherketon (CFRP) implants aim to reduce these artifacts. Our aim was to analyze susceptibility artifacts of these implants using a standardized in vitro model. Titanium and CFRP screw-rod phantoms were embedded in 3% agarose gel. Phantoms were scanned with Siemens Somatom AS Open and 3.0-T Siemens Skyra scanners. Regions of interest (ROIs) were plotted and analyzed for CT and MRI at clinically relevant localizations. CT voxel-based imaging analysis showed a significant difference of artifact intensity and central overlay between titanium and CFRP phantoms. For the virtual regions of the spinal canal, titanium implants (ti) presented - 30.7 HU vs. 33.4 HU mean for CFRP (p < 0.001), at the posterior margin of the vertebral body 68.9 HU (ti) vs. 59.8 HU (CFRP) (p < 0.001) and at the anterior part of the vertebral body 201.2 HU (ti) vs. 70.4 HU (CFRP) (p < 0.001), respectively. MRI data was only visually interpreted due to the low sample size and lack of an objective measuring system as Hounsfield units in CT. CT imaging of the phantom with typical implant configuration for thoracic stabilization could demonstrate a significant artifact reduction in CFRP implants compared with titanium implants for evaluation of index structures. Radiolucency with less artifacts provides a better interpretation of follow-up imaging, radiation planning, and more precise dose delivery.

Impact of the localization on disease course and clinical management in spondylodiscitis.

OBJECTIVES: Spondylodiscitis is a severe infection of the spine that can take a diverse number of disease courses depending on its localization, resulting in specific therapeutic strategies. This study aims to identify localization specific characteristics and clinical parameters for spondylodiscitis. METHODS: A retrospective review was performed of 211 patients from 2013-2018 with proven spondylodiscitis. In total, 33 were cervical, 48 thoracic and 112 lumbar. In 18 patients disseminated infestations of several localizations were found. The patient records were evaluated for clinical and outcome parameters and demographic characteristics. RESULTS: Patient age, Body Mass Index, inpatient and intensive care stay, and inpatient complications did not differ significantly between different infection localizations. C-reactive protein (CrP) levels showed a significantly reduced value in the thoracic area compared to other localizations. For comorbidities, there was a significantly higher prevalence of endocarditis in disseminated and lumbar infestations compared to thoracic and cervical cases. Epidural abscesses showed a highly increased incidence in cervical cases. With a 30-day mortality rate of 12.1% for cervical, 12.5% thoracic, 13.4% lumbar, and 22.2% in disseminated disease, no significant difference was observed. CONCLUSIONS: The present study determined that, although the 30-day mortality rate does not differ according to the localization of the infection, specific clinical parameters, such as CrP values or comorbidities, showed localization-dependent differences.

Intraocular pressure during neurosurgical procedures in context of head position and loss of cerebrospinal fluid.

OBJECTIVE: Perioperative visual loss (POVL) is a rare but serious complication in surgical disciplines, especially in spine surgery. The exact pathophysiology of POVL remains unclear, but elevated intraocular pressure (IOP) is known to be part of it. As POVL is rarely described in patients undergoing intracranial or intradural surgery, the aim of this study was to investigate the course of IOP during neurosurgical procedures with opening of the dura mater and loss of CSF. METHODS: In this prospective, controlled trial, 64 patients fell into one of 4 groups of 16 patients each. Group A included patients undergoing spine surgery in the prone position, group B patients had intracranial procedures in the prone position, and group C patients were treated for intracranial pathologies in a modified lateral position with the head rotated. In groups A-C, the dura was opened during surgery. Group D patients underwent spine surgeries in the prone position with an intact dura. IOP was measured continuously pre-, peri-, and postoperatively. RESULTS: In all groups, IOP decreased after induction of anesthesia and increased time dependently after final positioning for the operation. The maximum IOP in group A prior to opening of the dura was 28.6 ± 6.2 mm Hg and decreased to 23.44 ± 4.9 mm Hg directly after dura opening (p < 0.0007). This effect lasted for 30 minutes (23.5 ± 5.6 mm Hg, p = 0.0028); after 60 minutes IOP slowly increased again (24.5 ± 6.3 mm Hg, p = 0.15). In group B, the last measured IOP before CSF loss was 28.1 ± 5.0 mm Hg and decreased to 23.5 ± 6.1 mm Hg (p = 0.0039) after dura opening. A significant IOP decrease in group B lasted at 30 minutes (23.6 ± 6.0 mm Hg, p = 0.0039) and 60 minutes (23.7 ± 6.0 mm Hg, p = 0.0189). In group C, only the lower eye showed a decrease in IOP up to 60 minutes after loss of CSF (opening of dura, p = 0.0007; 30 minutes, p = 0.0477; 60 minutes, p = 0.0243). In group D (control group), IOP remained stable throughout the operation after the patient was prone. CONCLUSIONS: This study is the first to demonstrate that opening of the dura with loss of CSF during neurosurgical procedures results in a decrease in IOP. This might explain why POVL predominantly occurs in spinal but rarely in intracranial procedures, offers new insight to the pathophysiology of POVL, and provides the basis for further research and treatment of POVL.German Clinical Trials Register (DRKS) no.: DRKS00007590 (drks.de).

Extensive Spinal Adhesive Arachnoiditis After Extradural Spinal Infection-Spinal Dura Mater Is No Barrier to Inflammation.

BACKGROUND: Spinal adhesive arachnoiditis (SAA) is an inflammatory process of the meninges. Cystic changes and cicatrization may lead to neurologic deficits and immobilization. Therapy is difficult and often unsatisfactory. We describe 8 cases of extensive SAA after extradural spinal infection. METHODS: A total of 238 patients with epidural abscess or osteomyelitis were treated at our institution between 2011 and 2018. We identified 8 patients who developed extensive SAA on follow-up. Different forms of the disease, radiologic changes, and potential treatment options are described. RESULTS: Eight patients developed extensive SAA after either spontaneous epidural infection in 4 cases (50%) or after surgery or steroid injection (50%). Initial treatment for epidural infection was surgery without dural injury in 87.5%. One patient was treated conservatively. SAA was diagnosed 1 month to 8 years after the initial infection, not only in the index region but throughout the whole spine, with varying clinical symptoms. Treatment options such as corticosteroids (n = 4), thecaloscopy (n = 1), syringe-subarachnoid shunting (n = 1), and focal or multilevel arachnolysis (n = 5) were applied. In 2 patients (25%), a rare complication of internal malabsorptive hydrocephalus had to be treated. Patients showed diverse outcomes at last follow-up (mean, 37 months). CONCLUSIONS: The prognosis for extensive SAA is poor. Surgical interventions may improve radiologic findings and clinical presentation at least temporarily. Even extradural infection can lead to severe SAA. Early surgery with local reduction of the epidural infection might reduce the risk of inflammation passing the dural sac and causing SAA.

Surgical treatment of spinal metastases from renal cell carcinoma-effects of preoperative embolization on intraoperative blood loss.

The objective of this paper is analyzing the effects of preoperative embolization on intraoperative blood loss in spinal surgery for renal cell carcinoma (RCC) metastasis and identifying factors contributing to an increased blood loss in the surgical procedure. A retrospective analysis was performed in patients who were treated in for spinal metastasis from RCC between 2011 and 2016. Factors analyzed were reduction of tumor blush, timing of embolization, selective vs. superselective approach, surgical factors, and tumor volume and localization. Parameters were statistically correlated with intraoperative blood loss (hemoglobin (Hg) decrease, blood loss in milliliters, number of transfused blood bags). Twenty-five patients with 34 surgical interventions were included. Seventeen cases were treated superselectively and 11 treated selectively. Mean perioperative blood loss was 2248 ± 1833 ml. Higher blood loss was detected for vertebra replacement compared to percutaneous procedures (Hg decrease 4.22 vs. 2.62, p < 0.05). Blood loss increased with increasing tumor volumes (0-50 ccm/50-100 ccm/> 100 ccm) for Hg loss (3.29/3.64/4.24 mg/dl, NS), blood loss in milliliters (1291/2620/4971 ml, p < 0.001), and number of transfusions (1.2/3.4/7.0, p < 0.001). Stratifying by the grade of embolization, no significant differences were found between the groups (> 90%/90-75%/75-50%) for Hg loss, blood loss, or number of transfusions. Endovascular embolization for RCC metastasis of the spine is a safe procedure; however, in this cohort, patients undergoing embolization did not show a reduced blood loss in comparison to the non-embolized cohort. Additional factors contributing to an increased blood loss were tumor size and mode of surgery.

Impact of the surgical strategy on the incidence of C5 nerve root palsy in decompressive cervical surgery.

OBJECTIVE: Our aim was to identify the impact of different surgical strategies on the incidence of C5 palsy. BACKGROUND: Degenerative cervical spinal stenosis is a steadily increasing morbidity in the ageing population. Postoperative C5 nerve root palsy is a common complication with severe impact on the patients´ quality of life. METHODS: We identified 1708 consecutive patients who underwent cervical decompression surgery due to degenerative changes. The incidence of C5 palsy and surgical parameters including type and level of surgery were recorded to identify predictors for C5 nerve palsy. RESULTS: The overall C5 palsy rate was 4.8%, with 18.3% of cases being bilateral. For ACDF alone the palsy rate was low (1.13%), compared to 14.0% of C5 palsy rate after corpectomy. The risk increased with extension of the procedures. Hybrid constructs with corpectomy plus ACDF at C3-6 showed significantly lower rates of C5 palsy (10.7%) than corpectomy of two vertebrae (p = 0.005). Multiple regression analysis identified corpectomy of C4 or C5 as a significant predictor. We observed a lower overall incidence for ventral (4.3%) compared to dorsal (10.9%) approaches (p<0.001). When imaging detected a postoperative shift of the spinal cord at index segment C4/5, palsy rate increased significantly (33.3% vs. 12.5%, p = 0.034). CONCLUSIONS: Extended surgical strategies, such as dorsal laminectomies, multilevel corpectomies and procedures with extensive spinal cord shift were shown to display a high risk of C5 palsy. The use of extended procedures should therefore be employed cautiously. Switching to combined surgical methods like ACDF plus corpectomy can reduce the rate of C5 palsy.

Keyhole approaches to intradural pathologies.

OBJECTIVE Spinal tumors account for 2%-4% of all tumors of the central nervous system and can be intramedullary, intradural extramedullary, or extradural. In the past, wide approaches were used to obtain safe access to these tumors, as complete resection is the goal in treating most tumor entities. To reduce surgical complications due to large skin incisions and destabilizing laminectomies, minimally invasive approaches were established. In this study, the authors share their experience with mini-open approaches to intradural tumor pathologies. METHODS The authors retrospectively reviewed cases involving patients with intramedullary and intradural extramedullary lesions treated between 2009 and 2016. They present their surgical mini-open approach to the spinal cord as well as unique characteristics, key steps, and postsurgical complications for specific tumor subgroups (meningioma, neuroma, and intramedullary tumors). RESULTS A total of 245 intradural tumors were surgically treated during the study period. Of these lesions, 151 were intradural extramedullary meningiomas (n = 79) or neuromas (n = 72). Nine (12.5%) of the neuromas were dumbbell neuromas. Ninety-four tumors were intramedullary. The mean age of the patients was 51.4 years, and 53.9% were female. The mean duration of follow-up was 46.0 months. All meningiomas and neuromas could be resected using a mini-open keyhole approach, but only 5.3% of the intramedullary lesions could be accessed using this technique. Of the 94 patients with intramedullary tumors, 76.6% required a laminotomy, 7.4% required a hemilaminectomy, and 10.6% required a 2-level laminectomy. Only 2 of the patients with intramedullary tumors needed stabilization for progressive cervical kyphosis during follow-up. None of the other patients developed spinal instability after undergoing surgery via the mini-open (keyhole/interlaminar) approach. There were significantly more surgery-associated complications in the large exposure group than in the patients treated with the mini-open approach (19.1% vs 9.6%, p < 0.01). CONCLUSIONS Intradural extramedullary and in selected cases intramedullary pathologies may safely be resected using a mini-open interlaminar approach. Avoiding laminectomy, laminotomy, and even hemilaminectomy preserves spinal stability and significantly reduces comorbidities, while still allowing for complete resection of these tumors.

Impact of spinal cord compression from intradural and epidural spinal tumors on perioperative symptoms-implications for surgical decision making.

Spinal cord or cauda equina compression (SCC) is an increasing challenge in clinical oncology due to a higher prevalence of long-term cancer survivors. Our aim was to determine the clinical relevance of SCC regarding patient outcome depending on different tumor entities and their anatomical localization (extradural/intradural/intramedullary). We retrospectively analyzed 230 patients surgically treated for SCC. Preoperative status for pain and neurological impairment were correlated to the degree of compression, tumor location, and early as well as short-term follow-up outcome parameters. Interestingly, we did not observe any differences between intradural-extramedullary compared to extradural tumors. Unilaterally localized tumors were likely to present with pain (72.9 %, p < 0.01), whereas concentric growth was associated with motor deficits (41.0 %, p < 0.01, as primary symptom, 49.3 % on admission, p < 0.05). In concentric tumors, the pain pattern was diffuse (40.5 % vs. 17.5 in unilateral disease, p < 0.01), whereas unilateral tumors resulted in localized pain (61.4 % local axial or radicular, p < 0.01). Diffuse pain, patients without a sensory or motor deficit, progressive disease, cervical localization, and a higher degree of stenosis were identified as beneficial for an early improvement in pain (p < 0.05). Notably, 29 % of patients with unchanged pain and 30.8 % with unchanged neurologic function at day 7 postoperative improved during follow-up (p < 0.001). Our data demonstrate that the preoperative tumor anatomy in patients with SCC was closely related to their presenting symptoms and early clinical outcome. The detailed analysis elucidates the biology of SCC and might thereby aid in determining which patients will benefit from surgery.

Treatment of large thoracic and lumbar paraspinal schwannoma.

BACKGROUND: Paraspinal neurogenic tumors usually expand into the mediastinum and retroperitoneum and can reach a considerable size before they become symptomatic. Such large tumors are rare. We describe 14 cases of large schwannomas (>2.5 cm ø) with mild and late onset of symptoms, which were treated with total surgical resection through a single-approach surgery. METHODS: In 2013 14 patients with paraspinal large schwannomas were treated in our institutions. Data were analyzed retrospectively. Magnetic resonance imaging (MRI) showed lesions suspicious for a paraspinal schwannoma with partial intraforaminal growth. In case of ambiguity regarding tumor dignity, a needle biopsy was performed before final treatment. Three different approaches and their indications were discussed. RESULTS: Fourteen patients (7 female and 7 male, ages 18-58 years, mean: 39.8 years) requiring surgical exploration because of a thoracic (6) or lumbar/lumbosacral (8) lesion were treated in our institutions. Two patients received CT-guided needle biopsy preoperatively. Complete resection of the schwannoma was possible through a mini-thoracotomy in 1 case (7 %), a retroperitoneal approach in 2 cases (14 %), and dorsal interlaminar and intercostal fenestration in 11 cases (79 %). Histological examination revealed the diagnosis of schwannoma (WHO grade I) in all cases except one with neurofibroma (WHO grade I). There were no major complications in any case. CONCLUSION: Large benign schwannomas are rare. They need a tailored treatment, which in most cases works through one surgical approach. Usually it is possible to perform a complete resection with a good postoperative prognosis.