Tobias Finger

Microglia inflict delayed brain injury after subarachnoid hemorrhage

Inflammatory changes have been postulated to contribute to secondary brain injury after aneurysmal subarachnoid hemorrhage (SAH). In human specimens after SAH as well as in experimental SAH using mice, we show an intracerebral accumulation of inflammatory cells between days 4 and 28 after the bleeding. Using bone marrow chimeric mice allowing tracing of all peripherally derived immune cells, we confirm a truly CNS-intrinsic, microglial origin of these immune cells, exhibiting an inflammatory state, and rule out invasion of myeloid cells from the periphery into the brain. Furthermore, we detect secondary neuro-axonal injury throughout the time course of SAH. Since neuronal cell death and microglia accumulation follow a similar time course, we addressed whether the occurrence of activated microglia and neuro-axonal injury upon SAH are causally linked by depleting microglia in vivo. Given that the amount of neuronal cell death was significantly reduced after microglia depletion, we conclude that microglia accumulation inflicts secondary brain injury after SAH.

The Sagittal Balance Does not Influence the 1 Year Clinical Outcome of Patients With Lumbar Spinal Stenosis Without Obvious Instability After Microsurgical Decompression.

Study Design. A retrospective study with retrospective and prospective inclusion of 100 patients. Objective. To determine whether the sagittal balance (SB) influences the clinical outcome of patients with degenerative lumbar spinal stenosis, who underwent microsurgical decompression. Summary of Background Data. The SB has become a critical factor for clinical decision making in the surgical treatment of spinal degenerative diseases. However, a frequently recommended sagittal realignment of elderly, multimorbid patients is accompanied by a significant rate of complications. The influence of SB on the clinical outcome of patients with degenerative spinal stenosis, who undergo decompressive surgery is not well understood. The aim of this study was to explore whether the clinical outcome of these patients is related to the SB and whether patients with spinal stenosis and degenerative sagittal imbalance necessitate restoration of the SB in addition to microsurgical decompression. Methods. One hundred patients with lumbar spinal stenosis, who received microsurgical decompression, were retrospectively identified and classified according to the severity of sagittal imbalance: (1) normal balance group, (2) minor loss of balance group, and (3) major loss of balance group. Sagittal parameters were determined from preoperative lateral spinal radiographs. As outcome parameters, we analyzed pre- and postoperative visual analogue scales for leg and back pain, walking distance, Oswestry disability index, Roland and Morris disability questionnaire, Odoms criteria, and the SF-36 score. Results. All groups significantly benefited from surgery concerning leg pain, back pain, and disability in every days life. There was no difference in patients with decompensated sagittal imbalance compared to patients with normal SB regarding life quality 6 to 24 months after microsurgical decompression. Conclusions. Patients with symptomatic degenerative spinal stenosis and excluded major instability significantly benefit from microsurgical decompression regardless of their sagittal spinal balance. Thus, restoration of the SB for patients with symptomatic degenerative spinal stenosis cannot be recommended in addition to microsurgical decompression. Level of Evidence: 3

Application of titanium and polyetheretherketone cages in the treatment of pyogenic spondylodiscitis

OBJECTIVE Surgical treatment of a pyogenic spondylodiscitis (PSD) involves a fixation and debridement of the affected segment combined with a specific antibiotic therapy. To achieve a proper stability and to avoid pseudarthrosis and kyphotic malposition many surgeons favour the interposition of an anterior graft. Besides autologous bone grafts titanium (TTN) cages have gained acceptance in the treatment of PSD. Polyetheretherketone (PEEK) cages have a more favourable modulus of elasticity than TTN. We compared both cage types. Primary endpoints were the rate of reinfection and radiological results. METHODS From 2004 to 2013 51 patients underwent surgery for PSD with fixation and TTN or PEEK cage-implantation. While lumbar patients underwent a partial discectomy by the posterior approach, discs of the cervical and thoracic patients had been totally removed from anterior. Clinical and radiological parameters were assessed in 37 eligible patients after a mean of 20.4 months. 21 patients received a PEEK- and 16 patients a TTN-cage. RESULTS A reinfection after surgery and 3 months of antibiotic therapy was not observed. Solid arthrodesis was found in 90.5% of the PEEK-group and 100% of the TTN-group. A segmental correction could be achieved in both groups. Nonetheless, a cage subsidence was observed in 70.3% of all cases. Comparison of radiological results revealed no differences between both groups. CONCLUSIONS A debridement and fixation with anterior column support in combination with an antibiotic therapy appear to be the key points for successful treatment of PSD. The application of TTN- or PEEK-cages does not appear to influence the radiological outcome or risk of reinfection, neither does the extent of disc removal in this clinical subset.

Multiple reimplantation technique for treatment of complex giant aneurysms of the middle cerebral artery: technical note

BackgroundGiant middle cerebral artery (MCA) aneurysms are among the most challenging neurovascular lesions, especially when the M2 and M3 branches are incorporated into the aneurysm. Here we report on two cases with complex MCA aneurysms, in which double and triple arterial reimplantation of the efferent vessels into a saphenous vein graft (SVG) was applied to reconstruct the MCA tree, allowing final trapping of the aneurysm.MethodsIn the first case, a 41-year-old woman presented with a partially thrombosed giant MCA aneurysm including three efferent branches. Two superior trunks were disconnected and reimplanted onto an SVG fed by the external carotid artery (ECA). Following anastomosis between the SVG and the inferior trunk, the aneurysm was trapped. The second case is a 67-year-old man with recurrent giant MCA aneurysm incorporating two efferent M2 branches. First, the superior trunk was reimplanted onto an SVG, then the SVG was anastomosed to the inferior trunk. Finally the afferent M1 was clipped. Intraoperative indocyanine green (ICG) videoangiography (FLOW 800) was used for studying bypass patency.ResultsIn both cases, successful bypass patency was demonstrated by ICG videoangiography. Postoperative digital subtraction angiography (DSA) confirmed bypass patency. The first case was discharged without any neurological deficit. The second case suffered from bleeding due to refilling of the aneurysm via the inferior M2. An additional clip was placed on the inferior M2 in a second step. The patient was discharged with weakness of the left arm.ConclusionReconstructing an MCA bifurcation or trifurcation combining multiple arterial reimplantation is effective for treatment of selective cases of complex MCA aneurysms.

The sagittal spinal profile type: a principal precondition for surgical decision making in patients with lumbar spinal stenosis

OBJECTIVE Microsurgical decompression (MD) in patients with lumbar spinal stenosis (LSS) shows good clinical results. Nevertheless, 30%-40% of patients do not have a significant benefit after surgery-probably due to different anatomical preconditions. The sagittal profile types (SPTs 1-4) defined by Roussouly based on different spinopelvic parameters have been shown to influence spinal degeneration and surgical results. The aim of this study was to investigate the influence of the SPT on the clinical outcome in patients with LSS who were treated with MD. METHODS The authors retrospectively investigated 100 patients with LSS who received MD. The patients were subdivided into 4 groups depending on their SPT, which was determined from preoperative lateral spinal radiographs. The authors analyzed pre- and postoperative outcome scales, including the visual analog scale (VAS), walking distance, Oswestry Disability Index, Roland-Morris Disability Questionnaire, Odoms criteria, and the 36-Item Short Form Health Survey score. RESULTS Patients with SPT 1 showed a significantly worse clinical outcome concerning their postoperative back pain (VASback-SPT 1 = 5.4 ± 2.8; VASback-SPT 2 = 2.6 ± 1.9; VASback-SPT 3 = 2.9 ± 2.6; VASback-SPT 4 = 1.5 ± 2.5) and back pain-related disability. Only 43% were satisfied with their surgical results, compared with 70%-80% in the other groups. CONCLUSIONS A small pelvic incidence with reduced compensation mechanisms, a distinct lordosis in the lower lumbar spine with a high load on dorsal structures, and a long thoracolumbar kyphosis with a high axial load might lead to worse back pain after MD. Therefore, the indication for MD should be provided carefully, fusion can be considered, and other possible reasons for back pain should be thoroughly evaluated and treated.

Impact of timing of cranioplasty on hydrocephalus after decompressive hemicraniectomy in malignant middle cerebral artery infarction

OBJECTIVE Patients with malignant middle cerebral artery infarction frequently develop hydrocephalus after decompressive hemicraniectomy. Hydrocephalus itself and known shunt related complications after ventriculo-peritoneal shunt implantation may negatively impact patientś outcome. Here, we aimed to identify factors associated with the development of hydrocephalus after decompressive hemicraniectomy in malignant middle cerebral artery infarction. PATIENTS AND METHODS A total of 99 consecutive patients with the diagnosis of large hemispheric infarctions and the indication for decompressive hemicraniectomy were included. We retrospectively evaluated patient characteristics (gender, age and selected preoperative risk factors), stroke characteristics (side, stroke volume and existing mass effect) and surgical characteristics (size of the bone flap, initial complication rate, time to cranioplasty, complication rate following cranioplasty, type of implant, number of revision surgeries and mortality). RESULTS Frequency of hydrocephalus development was 10% in our cohort. Patients who developed a hydrocephalus had an earlier time point of bone flap reimplantation compared to the control group (no hydrocephalus=164±104days, hydrocephalus=108±52days, p<0.05). Additionally, numbers of revision surgeries after cranioplasty was associated with hydrocephalus with a trend towards significance (p=0.08). CONCLUSION Communicating hydrocephalus is frequent in patients with malignant middle cerebral artery infarction after decompressive hemicraniectomy. A later time point of cranioplasty might lead to a lower incidence of required shunting procedures in general as we could show in our patient cohort.

Two-level cervical corpectomy—long-term follow-up reveals the high rate of material failure in patients, who received an anterior approach only

In contrast to a one-level cervical corpectomy, a multilevel corpectomy without posterior fusion is accompanied by a high material failure rate. So far, the adequate surgical technique for patients, who receive a two-level corpectomy, remains to be elucidated. The aim of this study was to determine the long-term clinical outcome of patients with cervical myelopathy, who underwent a two-level corpectomy. Outcome parameters of 21 patients, who received a two-level cervical corpectomy, were retrospectively analyzed concerning reoperations and outcome scores (VAS, Neck Disability Index (NDI), Nurick scale, modified Japanese Orthopaedic Association score (mJOAS), Short Form 36-item Health Survey Questionnaire (SF-36)). The failure rate was determined using postoperative radiographs. The choice over the surgical procedures was exercised by every surgeon individually. Therefore, a distinction between two groups was possible: (1) anterior group (ANT group) with a two-level corpectomy and a cervical plate, (2) anterior/posterior group (A/P group) with two-level corpectomy, cervical plate, and additional posterior fusion. Both groups benefitted from surgery concerning pain, disability, and myelopathy. While all patients of the A/P group showed no postoperative instability, one third of the patients of the ANT group exhibited instability and clinical deterioration. Thus, a revision surgery with secondary posterior fusion was needed. Furthermore, the ANT group had worse myelopathy scores (mJOASANT group = 13.5 ± 2.5, mJOASA/P group = 15.7 ± 2.2). Patients with myelopathy, who receive a two-level cervical corpectomy, benefitted from surgical decompression. However, patients with a sole anterior approach demonstrated a very high rate of instability (33%) and clinical deterioration in a long-term follow-up. Therefore, we recommend to routinely perform an additional posterior fusion after two-level cervical corpectomy.

Brain death after decompressive craniectomy: Incidence and pathophysiological mechanisms

Purpose: Patients who received decompressive craniectomy (DC) are usually not regarded to qualify for brain death (BD) as intracranial pressure (ICP) is not assumed to reach levels critical enough to cause cerebral perfusion failure. Here we investigated the incidence of BD after DC and analyzed the pathophysiological mechanisms. Materials and methods: We searched our chart records of patients with DC for individuals who developed BD (2010–2016). We then analyzed the course of ICP and cerebral perfusion pressure (CPP) prior to BD and results from radiological tests that aim at demonstrating loss of cerebral perfusion in BD. Results: BD was diagnosed in 12 of 164 (incidence 7.3%) patients (age = 16–70 years; male = 7; mean longitudinal diameter: 136.2 mm). Mean latency between DC and BD was 69.4 h. Immediately after DC, mean ICP was 30.0 mm Hg (standard deviation ± 24.7 mm Hg), CPP was 56.8 mm Hg (± 28.1). In the course to BD, ICP increased to 95.8 mm Hg (± 16.1), CPP decreased to − 9.9 mm Hg (± 11.2). In patients in whom radiological methods were performed (n = 5) loss of cerebral perfusion was demonstrated. Conclusions: Our study evidences that DC does not exclude BD. Even after DC, BD is preceded by a severely reduced CPP, supporting loss of cerebral perfusion as a critical step in BD pathophysiology. HighlightsOur study evidences that decompressive craniectomy (DC) does not exclude brain death (BD) development.Incidence of BD after DC in our study was 7.3%.Even in patients with DC, BD is preceded by a severely reduced cerebral perfusion pressure (CPP).Similar to patients without DC, critical closing pressure may be within positive ranges of CPP.Pathophysiology of BD after DC seems to be equal to BD without DC after primary brain injury.

Revision surgery for cervical artificial disc: Surgical technique and clinical results

OBJECTIVE Cervical artificial disc replacement (C-ADR) was developed with the goal of preserving mobility of the cervical segment in patients with degenerative disc disease. So far, little is known about experiences with revision surgery and explantation of C-ADRs. Here, we report our experience with revision the third generation, Galileo-type disc prosthesis from a retrospective study of two institutions. PATIENTS AND METHODS Between November 2008 and July 2016, 16 patients with prior implantation of C-ADR underwent removal of the Galileo-type disc prosthesis (Signus, Medizintechnik, Germany) due to a call back by industry. In 10 patients C-ADR was replaced with an alternative prosthesis, 6 patients received an ACDF. Duration of surgery, time to revision, surgical procedure, complication rate, neurological status, histological findings and outcome were examined in two institutions. RESULTS The C-ADR was successfully revised in all patients. Surgery was performed through the same anterior approach as the initial access. Duration of the procedure varied between 43 and 80min. Access-related complications included irritation of the recurrent nerve in one patient and mal-positioning of the C-ADR in another patient. Follow up revealed two patients with permanent mild/moderate neurologic deficits, NDI (neck disability index) ranged between 10 and 42%. CONCLUSIONS Anterior exposure of the cervical spine for explantation and revision of C-ADR performed through the initial approach has an overall complication rate of 18.75%. Replacements of the Galileo-type disc prosthesis with an alternative prosthesis or conversion to ACDF are both suitable surgical options without significant difference in outcome.