Reconstruction of the Corticospinal Tract in Patients with Motor-Eloquent High-Grade Gliomas Using Multilevel Fiber Tractography Combined with Functional Motor Cortex Mapping.

BACKGROUND AND PURPOSE: Tractography of the corticospinal tract is paramount to presurgical planning and guidance of intraoperative resection in patients with motor-eloquent gliomas. It is well-known that DTI-based tractography as the most frequently used technique has relevant shortcomings, particularly for resolving complex fiber architecture. The purpose of this study was to evaluate multilevel fiber tractography combined with functional motor cortex mapping in comparison with conventional deterministic tractography algorithms. MATERIALS AND METHODS: Thirty-one patients (mean age, 61.5 [SD, 12.2] years) with motor-eloquent high-grade gliomas underwent MR imaging with DWI (TR/TE = 5000/78 ms, voxel size = 2 × 2 × 2 mm3, 1 volume at b = 0 s/mm2, 32 volumes at b = 1000 s/mm2). DTI, constrained spherical deconvolution, and multilevel fiber tractography-based reconstruction of the corticospinal tract within the tumor-affected hemispheres were performed. The functional motor cortex was enclosed by navigated transcranial magnetic stimulation motor mapping before tumor resection and used for seeding. A range of angular deviation and fractional anisotropy thresholds (for DTI) was tested. RESULTS: For all investigated thresholds, multilevel fiber tractography achieved the highest mean coverage of the motor maps (eg, angular threshold = 60°; multilevel/constrained spherical deconvolution/DTI, 25% anisotropy threshold = 71.8%, 22.6%, and 11.7%) and the most extensive corticospinal tract reconstructions (eg, angular threshold = 60°; multilevel/constrained spherical deconvolution/DTI, 25% anisotropy threshold = 26,485 mm3, 6308 mm3, and 4270 mm3). CONCLUSIONS: Multilevel fiber tractography may improve the coverage of the motor cortex by corticospinal tract fibers compared with conventional deterministic algorithms. Thus, it could provide a more detailed and complete visualization of corticospinal tract architecture, particularly by visualizing fiber trajectories with acute angles that might be of high relevance in patients with gliomas and distorted anatomy.

[C5 palsy after multi-segmental cervical decompression : How can it be avoided?] / Die C5-Parese nach multisegmentaler zervikaler Dekompression : Wie kann diese vermieden werden?

BACKGROUND: Anterior cervical discectomy and fusion (ACDF) as well as posterior instrumentation of the cervical spine are frequently performed surgeries for cervical disc prolapse or spinal stenosis. Surgery itself harbors a very low risk of adverse events. Postoperative palsy of the C5 nerve root, however, is a severe complication and its origin is still not fully understood. The risk of such a C5 palsy is reported to be between 0 and 30%; 5% on average according to the literature. OBJECTIVES: To describe underlying pathomechanisms and to recommend strategies for risk reduction. MATERIALS AND METHODS: An extensive literature research via Medline was performed. RESULTS: Potential risk factors are male gender, sagittal diameter below 5.6 mm, anterior approach, and higher age. CONCLUSIONS: Currently available data only originates from retrospective or anatomical studies. A prospective register study with the goal to put light on the pathogenesis is currently being performed.

[Surgical treatment of adult spinal deformities]. / Operative Behandlung adulter spinaler Deformitäten.

BACKGROUND: Adult spinal deformity (ASD) is mostly a progressive disease which usually leads to chronic pain. Due to increased prevalence in older people many patients suffer from comorbidities, which make conservative and surgical treatment even more complex. OBJECTIVE: This article provides an overview on the current conservative and surgical treatment options. MATERIAL AND METHODS: An extensive literature search was carried out via Medline plus an additional evaluation of the authors' personal experiences was performed. RESULTS: The current conservative and surgical treatments are outlined and potential risk factors and predictors which may lead to inferior clinical outcome are discussed. CONCLUSION: Patients for whom even conservative treatment leads to success should be identified earlier and better. The surgical treatment ranges from minimally invasive decompression to multilevel fusions. Complications in large corrective interventions can be substantial but if the indications are correctly assessed, such complex surgical treatment has excellent clinical results in terms of pain and quality of life.

[Operative options for failed back surgery syndrome]. / Operative Therapiemöglichkeiten beim Postnukleotomiesyndrom.

BACKGROUND: Post-nucleotomy syndrome includes all existing sequelae after surgical nucleotomy for the resection of a lumbar disc herniation, such as axial lumbar back pain and persisting radiculopathy. OBJECTIVES: To describe underlying pathologies and to determine operative treatment options. MATERIALS AND METHODS: Extensive literature research was carried out on Medline. RESULTS: Various devices and approaches have been developed in the last decades. Nonetheless, surgical and non-surgical therapy of post-nucleotomy syndrome remains complex and frequently fails. CONCLUSIONS: Better studies providing a better level of evidence for each sub-entity of post-nucleotomy syndrome are required.

[Spinal column: implants and revisions]. / Wirbelsäule: Implantate und Revisionen.

Non-fusion spinal implants are designed to reduce the commonly occurring risks and complications of spinal fusion surgery, e.g. long duration of surgery, high blood loss, screw loosening and adjacent segment disease, by dynamic or movement preserving approaches. This principle could be shown for interspinous spacers, cervical and lumbar total disc replacement and dynamic stabilization; however, due to the continuing high rate of revision surgery, the indications for surgery require as much attention and evidence as comparative data on the surgical technique itself.

Anterior clinoidectomy.

BACKGROUND: The optic nerve within the optic canal, the parophthalmic segment of the carotid artery, and the oculomotor nerve in the superior orbital fissure all lay against the anterior clinoid process. Bone resection uncovers these structures. METHOD: For extradural resection of the anterior clinoid process and surrounding bone, two key steps are recommended: bony opening of the superior orbital fissure, and transection of the orbitotemporal periosteal fold. CONCLUSION: Anterior clinoidectomy is technically challenging. Following a sequence of surgical steps to expose clearly-defined surgical landmarks helps to make this procedure simple and safe. KEY POINTS: • Pterional craniotomy • Complete extradural anterior clinoidectomy • Slit dura (3 mm) to drain cerebrospinal fluid • Peel dura from orbital roof and lateral wall • Bony opening of superior orbital fissure to use it as surgical corridor • Drilling of optic canal • Transection of orbitotemporal periosteal fold • Hollow anterior clinoid process and piece-meal resection • Transection of falciforme ligament to free optic nerve • Replace falciforme ligament by extradural free pericranial flap.