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  • Author or Editor: Dimitris G. Placantonakis x
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Dimitris G. Placantonakis, Eric Lis and Mark M. Souweidane

✓Intradiploic cerebrospinal fluid (CSF) collections represent a rare complication of either head trauma or neurosurgical procedures. Their formation is thought to depend partly on violation of the meninges and the inner cortical bone abutting the neuraxis. The authors present two pediatric cases involving diploic CSF collections following neurosurgical interventions. In the first case, a CSF fistula was found within the occipital bone and the petrous portion of the temporal bone 9 years after a suboccipital craniectomy. The second case features the extremely rare occurrence of a CSF fistula within a thoracic vertebra, 9 years after a laminectomy. Both patients underwent successful surgical procedures for repair of the fistulas.

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Bartosz T. Grobelny, David Rubin, Peter Fleischut, Elayna Rubens, Patricia Fogarty Mack, Matthew Fink, Dimitris G. Placantonakis and Eric H. Elowitz

Fibrodysplasia ossificans progressiva (FOP) is a rare genetic disorder characterized by heterotopic ossification of soft connective and muscle tissues, often as the result of minor trauma. The sequelae include joint fusion, accumulation of calcified foci within soft tissues, thoracic insufficiency syndrome, and progressive immobility. The authors report on a patient with FOP who developed severe spinal canal stenosis in the thoracic spine causing substantial myelopathy. He underwent a thoracic laminectomy and resection of a large posterior osteophyte. Unique considerations are required in treating patients with FOP, including steroid administration to prevent ossification and anesthetic technique. The nuances of neurosurgical and medical management as they pertain to this disease are discussed.

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Dimitris G. Placantonakis, Ilya Laufer, Jeremy C. Wang, Jasmine S. Beria, Patrick Boland and Mark Bilsky

Object

In this retrospective analysis the authors describe the assessment and outcomes of 90 patients who underwent placement of posterior instrumentation at the cervicothoracic junction following the resection of a primary or metastatic tumor during a 10-year period.

Methods

All patients underwent a posterolateral laminectomy including uni- or bilateral facetectomy, and 44 patients additionally required vertebral body resection and reconstruction. In patients who underwent C-6 or C-7 decompression, the posterior instrumentation strategies changed from the use of lateral mass plate systems (LMPSs) to lateral mass screw/rod systems (LMSRSs). Similarly, for T1–3 tumor decompression, the strategy shifted from sublaminar hook/rod systems (SHRSs) to the use of pedicle screw systems (PSSs) in which the surgeon used either a 6.25-mm rod or dual-diameter rods with or without a connector.

Results

The overall surgical complication rate was 19% including fixation failure in 11 patients (12%), 6 of whom required reoperation. Fixation failure rates for cervical decompression decreased from 2 (29%) of 7 patients in the LMPS group to 0 (0%) of 8 in the LMSRS group (p = 0.2). The fixation failure rates for thoracic decompression were 7 (15%) of 48 patients in the SHRS group, and there was a decrease to 2 (7%) of 27 in the PSS group (p = 0.48). Neurological and functional outcomes including American Spinal Injury Association, Eastern Cooperative Oncology Group, and Medical Research Council muscle strength and pain scores remained stable or improved in 94, 96, 100, and 96% of patients, respectively.

Conclusions

Current posterior instrumentation strategies involving LMSRSs and PSSs provide excellent and safe stabilization of the cervicothoracic junction following resection of primary or metastatic tumors.

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Georgios P. Skandalakis, Spyridon Komaitis, Aristotelis Kalyvas, Evgenia Lani, Chrysoula Kontrafouri, Evangelos Drosos, Faidon Liakos, Maria Piagkou, Dimitris G. Placantonakis, John G. Golfinos, Kostas N. Fountas, Eftychia Z. Kapsalaki, Constantinos G. Hadjipanayis, George Stranjalis and Christos Koutsarnakis

OBJECTIVE

Although a growing body of data support the functional connectivity between the precuneus and the medial temporal lobe during states of resting consciousness as well as during a diverse array of higher-order functions, direct structural evidence on this subcortical circuitry is scarce. Here, the authors investigate the very existence, anatomical consistency, morphology, and spatial relationships of the cingulum bundle V (CB-V), a fiber tract that has been reported to reside close to the inferior arm of the cingulum (CingI).

METHODS

Fifteen normal, formalin-fixed cerebral hemispheres from adults were treated with Klingler’s method and subsequently investigated through the fiber microdissection technique in a medial to lateral direction.

RESULTS

A distinct group of fibers is invariably identified in the subcortical territory of the posteromedial cortex, connecting the precuneus and the medial temporal lobe. This tract follows the trajectory of the parietooccipital sulcus in a close spatial relationship with the CingI and the sledge runner fasciculus. It extends inferiorly to the parahippocampal place area and retrosplenial complex area, followed by a lateral curve to terminate toward the fusiform face area (Brodmann area [BA] 37) and lateral piriform area (BA35). Taking into account the aforementioned subcortical architecture, the CB-V allegedly participates as a major subcortical stream within the default mode network, possibly subserving the transfer of multimodal cues relevant to visuospatial, facial, and mnemonic information to the precuneal hub. Although robust clinical evidence on the functional role of this stream is lacking, the modern neurosurgeon should be aware of this tract when manipulating cerebral areas en route to lesions residing in or around the ventricular trigone.

CONCLUSIONS

Through the fiber microdissection technique, the authors were able to provide original, direct structural evidence on the existence, morphology, axonal connectivity, and correlative anatomy of what proved to be a discrete white matter pathway, previously described as the CB-V, connecting the precuneus and medial temporal lobe.