Diffusion-weighted magnetic resonance (DW-MR) neurography of the lumbar plexus in the preoperative planning of lateral access lumbar surgery.

By London Spine
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Diffusion-weighted magnetic resonance (DW-MR) neurography of the lumbar plexus in the preoperative planning of lateral access lumbar surgery.

Eur Spine J. 2015 Apr;24(4):817-26

Authors: Menezes CM, de Andrade LM, Herrero CF, Defino HL, Ferreira Júnior MA, Rodgers WB, Nogueira-Barbosa MH

Abstract
PURPOSE: Magnetic resonance (MR) neurography has been used to evaluate entire nerves and nerve bundles by providing better contrast between the nerves and the surrounding tissues. The purpose of the study was to validate diffusion-weighted MR (DW-MR) neurography in visualizing the lumbar plexus during preoperative planning of lateral transpsoas surgery.
METHODS: Ninety-four (188 lumbar plexuses) spine patients underwent a DW-MR examination of the lumbar plexus in relation to the L3-4 and L4-5 disc spaces and superior third of the L5 vertebral body. Images were reconstructed in the axial plane using high-resolution Maximum Intensity projection (MIP) overlay templates at the disc space and L3-4 and L4-5 interspaces. 10 and 22 mm MIP templates were chosen to mimic the working zone of standard lateral access retractors. The positions of the L4 nerve root and femoral nerve were analyzed relative to the L4-5 disc in axial and sagittal planes. Third-party radiologists and a senior spine surgeon performed the evaluations, with inter- and intraobserver testing performed.
RESULTS: In all subjects, the plexus was successfully mapped. At L3-4, in all but one case, the components of the plexus (except the genitofemoral nerve) were located in the most posterior quadrant (zone IV). The L3 and L4 roots coalesced into the femoral nerve below the L4-5 disc space in all subjects. Side-to-side variation was noted, with the plexus occurring in zone IV in 86.2 % right and only 78.7 % of left sides. At the superior third of L5, the plexus was found in zone III in 27.7 % of right and 36.2 % of left sides; and in zone II in 4.3 % right and 2.1 % left sides. Significant inter- and intraobserver agreement was found.
CONCLUSIONS: By providing the surgeon with a preoperative roadmap of the lumbar plexus, DW-MR may improve the safety profile of lateral access procedures.

PMID: 25266892 [PubMed – indexed for MEDLINE]

[Reckoning: Assessment of 21 years’ work in spinal surgery].

By London Spine
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[Reckoning: Assessment of 21 years’ work in spinal surgery].

Orv Hetil. 2015 Apr;156(15):598-607

Authors: Illés ST

Abstract
INTRODUCTION: Of the world-wide used Cotrel-Dubousset instrumentation and surgical technique providing breakthrough for the three-dimensional correction and multi-segmental fixation of spinal deformity surgery in Hungary is linked to the author’s name, who carried out 1655 spine deformity surgeries in the last 21 years.
AIM: The aim of the author was to discuss his own results in the field of spine surgery and compare his own data to those published in the international literature.
METHOD: At the beginning hooks, followed by hybrid instrumentation with hooks in thoracic area and transpedicular screws in lumbar spine have been used for the segmental fixation. During the correction process, initially the classic derotation maneuver was used, followed by the translation and then the in situ bending techniques and, finally, a combination of the above three techniques have been applied.
RESULTS: In addition to the restoration of normal sagittal balance, an average of 40.8° (SD, 25.9), a 65.5% correction was achieved in the frontal plane, which partly exceeds and partly consistent with the published international results. The incidence of inflammation (3.9%), and mechanical complications (1.7%) was similar to the international average, while the incidence of neurological complications (0.48%) was slightly lower than the average of international data.
CONCLUSIONS: The author believes that the better correction results as compared to the international average could be due to the always consistent application of the Cotrel-Dubousset instrumentation correction philosophy based on the meticulous segmental analysis of spine deformities.

PMID: 25845319 [PubMed – indexed for MEDLINE]

Multifocal intradural extramedullary ependymoma. Case report.

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Multifocal intradural extramedullary ependymoma. Case report.

J Neurosurg Spine. 2011 Jan;14(1):65-70

Authors: Iunes EA, Stávale JN, de Cássia Caldas Pessoa R, Ansai R, Onishi FJ, de Paiva Neto MA, de Pádua Bonatelli A, Cavalheiro S, Fleury Malheiros SM

In this paper, the authors present the case of a patient with multifocal intradural extramedullary ependymoma, and they review 18 previously reported cases. A 32-year-old man presented to the authors’ institution with a 1-month history of partial medullary syndrome. Magnetic resonance imaging of the neuraxis revealed multifocal intradural extramedullary lesions at the bulbomedullary junction and C2-3, T5-11, L-2, L-4, L-5, and sacrum. Histological examination revealed a WHO Grade II ependymoma. The literature survey yielded 18 cases of ependymoma at the same location; none of them were multifocal at presentation. The authors analyzed the epidemiological, clinical, and surgical features of all 19 cases reported to date, including the present case. Patients’ ages ranged from 24 to 69 years; 15 patients were women and 4 were men. The time elapsed from symptom onset to diagnosis ranged from 1 month to 8 years. Pain (in 13 patients) and medullary syndrome (in 12) were reported as the initial symptoms (information was not provided for 1 patient). Tumors were predominantly located in the thoracic spine (11), but they also occurred in the cervicothoracic (3), cervical (2), and lumbar (2) spine. The remaining tumor was multifocal. Solitary extramedullary tumors were found intraoperatively in 13 patients; 3 were described as exophytic and 3 as extramedullary with some degree of medullary invasion. Histological examination revealed 9 WHO Grade II tumors, 4 Grade III tumors, and 1 myxopapillary tumor. Data obtained for the remaining cases proved inconclusive. The clinical condition improved in 11 patients, remained stable in 2, and worsened (recurrence or progression) in 6. Of the 4 patients with Grade II tumors who presented with recurrence or neuraxis spreading, 3 had meningeal infiltration or adhesion to the pia mater, which does not rule out the possibility of neoplastic remnants in that area. Intradural extramedullary ependymomas are rare, they predominate in women in the 5th decade of life, and pain is the most frequent initial symptom. The extent of resection and the presence of meningeal infiltration seem to be key determinants of prognosis. The present case is the first intradural extramedullary ependymoma (with the exception of those occurring at the conus medullaris and terminal filum) with multiple lesions at presentation.

PMID: 21142461 [PubMed – indexed for MEDLINE]

Blockade of peripheral and spinal Na+/H+ exchanger increases formalin-induced long-lasting mechanical allodynia and hyperalgesia in rats.

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Blockade of peripheral and spinal Na+/H+ exchanger increases formalin-induced long-lasting mechanical allodynia and hyperalgesia in rats.

Brain Res. 2012 Sep 26;1475:19-30

Authors: Castañeda-Corral G, Rocha-González HI, Araiza-Saldaña CI, Vidal-Cantú GC, Miguel Jiménez-Andrade J, Murbartián J, Granados-Soto V

Abstract
The Na(+)/H(+) exchanger (NHE) is involved in the regulation of intracellular pH and volume by mediating the electroneutral transport of H(+) against an influx of Na(+) ions. Since NHE1 regulates pH in neurons and astrocytes and it is expressed in nociceptive nerve fibers, it is likely that NHE may modulate neuronal excitability and pain transmission. The purpose of this study was to assess the participation of peripheral and spinal NHE in the secondary allodynia/hyperalgesia induced by formalin. In addition, we determined whether formalin injection modifies the expression of NHE1 in lumbar dorsal root ganglia (DRG) and dorsal spinal cord. Subcutaneous injection of 0.5% formalin into the dorsal surface of the hind paw produced acute nociceptive behaviors (flinching and licking/lifting) followed by long-lasting bilateral secondary mechanical allodynia/hyperalgesia. Peripheral and intrathecal pre-treatment (-10min) with selective NHE inhibitors 5-(N,N-dimethyl)amiloride hydrochloride (DMA, 0.3-30μM), 5-(N-ethyl-N-isopropyl)amiloride (EIPA, 0.3-30μM) and [1-(quinolin-5-yl)-5-cyclopropyl-1H-pyrazole-4-carbonyl] guanidine dihydrochloride (zoniporide, 0.03-3μM) significantly increased 0.5% formalin-induced bilateral long-lasting secondary allodynia/hyperalgesia. Contrariwise, local peripheral or intrathecal post-treatment (day 6 postinjection) with these NHE inhibitors did not affect formalin-induced nociceptive behaviors. Formalin injection reduced NHE1 expression in ipsilateral and contralateral spinal dorsal horns from day 1 to 12. In addition, formalin diminished NHE1 protein expression in DRG at day 12. These results suggest that NHE1 plays a role in pain processing at peripheral and spinal levels in formalin-induced long-lasting nociceptive behaviors. Additionally, these results suggest that proteins involved in pH regulation could be targets for the development of new analgesic drugs.

PMID: 22898152 [PubMed – in process]