Tag: Metastasis

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Red-light excitation of protoporphyrin IX fluorescence for subsurface tumor detection

J Neurosurg 128:1690–1697, 2018

The objective of this study was to detect 5-aminolevulinic acid (ALA)-induced tumor fluorescence from glioma below the surface of the surgical field by using red-light illumination.

METHODS To overcome the shallow tissue penetration of blue light, which maximally excites the ALA-induced fluorophore protoporphyrin IX (PpIX) but is also strongly absorbed by hemoglobin and oxyhemoglobin, a system was developed to illuminate the surgical field with red light (620–640 nm) matching a secondary, smaller absorption peak of PpIX and detecting the fluorescence emission through a 650-nm longpass filter. This wide-field spectroscopic imaging system was used in conjunction with conventional blue-light fluorescence for comparison in 29 patients undergoing craniotomy for resection of high-grade glioma, low-grade glioma, meningioma, or metastasis.

RESULTS Although, as expected, red-light excitation is less sensitive to PpIX in exposed tumor, it did reveal tumor at a depth up to 5 mm below the resection bed in 22 of 24 patients who also exhibited PpIX fluorescence under blue-light excitation during the course of surgery.

CONCLUSIONS Red-light excitation of tumor-associated PpIX fluorescence below the surface of the surgical field can be achieved intraoperatively and enables detection of subsurface tumor that is not visualized under conventional bluelight excitation. Clinical trial registration no.: NCT02191488 (clinicaltrials.gov)

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Differentiating brain radionecrosis from tumour recurrence: a role for contrast-enhanced ultrasound?

Acta Neurochir (2017) 159:2405–2408

Differentiating radionecrosis from tumour recurrence is a major issue in neuro-oncology. Conventional imaging is far from being validated as an alternative to histologicalassessment.

We report the case of a patient operated on for suspected recurrence of brain metastasis 9 months after cyberknife radiosurgery. While magnetic resonance imaging showed strong enhancement of the lesion, intraoperative contrast-enhanced ultrasonography (CEUS) surprisingly did
not—different from what is expected for brain metastases.

Histopathological examination documented radionecrosis. For the first time, we describe radionecrosis with CEUS; further investigation is needed; however, the lack of enhancement could represent an important hallmark in differential diagnosis with neoplastic tissue.

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Axial Spondylectomy and Circumferential Reconstruction via a Posterior Approach

Axial spondylectomy

Neurosurgery 72:300–309, 2013

Spinal metastases of the second cervical vertebra are a subset of tumors that are particularly difficult to address surgically. Previously described techniques require highly morbid circumferential dissection posterior to the pharynx for resection and reconstruction.

OBJECTIVE: To perform a biomechanical analysis of instrumented reconstruction configurations used after axial spondylectomy and to demonstrate safe use of a novel construct in a patient case report.

METHODS: Several different published and novel reconstruction configurations were inserted into 7 occipitocervical spines that underwent axial spondylectomy. A biomechanical analysis of the stiffness of the constructs in flexion and extension, lateral bending, and rotation was performed. A patient then underwent a posterior-only approach for axial spondylectomy and circumferential reconstruction.

RESULTS: Biomechanical analysis of different constructs demonstrated that anterior column reconstruction with bilateral cages spanning the C1 lateral mass to the C3 facet in combination with occipitocervical instrumentation was superior in flexion-extension and equivalent in lateral bending and rotation to currently used constructs. The patient in whom this construct was placed via a posterior-only approach for axial spondylectomy and instrumentation remained at neurological baseline and demonstrated no recurrence of local disease or failure of instrumentation to date.

CONCLUSION: When C1 lateral mass to C3 facet bilateral cage plus occipitocervical instrumentation is compared with existing anterior and posterior constructs, this novel reconstruction is biomechanically equivalent if not superior in performance. In a patient, the posterior-only approach for C2 spondylectomy with the novel reconstruction was safe and durable and avoided the morbidity of the anterior approach.

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The enigma of bifocal germ cell tumors in the suprasellar and pineal regions: synchronous lesions or metastasis?

The enigma of bifocal germ cell tumors in the suprasellar

J Neurosurg Pediatrics 11:107–114, 2013

Intracranial germ cell tumors (GCTs) frequently present with bifocal lesions in both the suprasellar and pineal areas. The pathogenesis of these bifocal GCTs has been the subject of controversy. Bifocal GCTs may be caused by synchronous tumors or by metastatic spread of tumor cells from one site to the other. The prognosis associated with bifocal GCTs has also been a cause of concern.

Methods. The authors constructed a single-institution patient cohort comprising 181 patients with intracranial GCTs. The clinical characteristics of bifocal GCTs were compared with those of suprasellar and pineal GCTs.

Results. Bifocal GCTs were observed in 23 patients (12.8%). Eighteen patients presented with bifocal GCTs that were diagnosed as germinomas, but 5 patients exhibited mixed GCTs. Analyses of age distributions and comparisons of tumor sizes were compatible with a model of a metastatic origin of bifocal GCTs. Eleven patients (47.8%) presenting with bifocal GCTs exhibited tumor seeding at presentation. Tumor seeding was significantly associated with bifocal lesions (p < 0.001). Patients with bifocal germinomas showed significantly shorter event-free survival and overall survival than did those presenting with germinomas from a single site of origin.

Conclusions. Bifocal GCTs are not restricted to germinomas, as had been previously reported, but do include mixed GCTs. The authors hypothesize that bifocal GCTs may result from the metastatic spread of suprasellar or pineal GCTs. The bifocal presentation of germinomas may be a poor prognostic sign and should alert clinicians to the possibility of a disseminated disease.

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Intradural spinal metastases: a surgical series of 15 patients

Acta Neurochir (2012) 154:871–877. DOI 10.1007/s00701-012-1313-5

Intradural spinal metastases are rare, and little is known regarding surgical indications and outcomes.

Methods A retrospective search identified adults with intradural spinal metastases operated on at the Mayo Clinic from 1994-2011. Data were collected regarding demographics, tumor type and location, and outcomes.

Results Fifteen patients with intradural spinal metastases were investigated. The age range was 38-74 years (mean= 55 years; ±SD=11.1). Predominant tumor location and type were lumbosacral and adenocarcinoma, respectively: 3 intramedullary and 12 extramedullary. Patients were operated on to relieve or prevent progressive/intractable neurological sequelae and/or pain. Of 13 who underwent resection, gross total removal was reported in 10; simple biopsy was performed in 2. There was one surgical complication, no medical complications, and no surgical mortality. At median follow-up of 1 month postoperatively, 10 of 15 patients were stable or improved. Of 13 patients who underwent resection, 10 were stable or improved. Of two patients who underwent biopsy, neither was stable or improved at follow-up. Using the Modified McCormick Scale, 11 of 15 patients were “functional” preoperatively and 4 went from “functional” preoperatively to “non-functional” postoperatively. Three of those four died within 60 days of surgery from systemic disease progression. Median hospital stay was 8 days. Ten of 15 patients died by the end of the study period, and the median survival of 15 patients was 5 months.

Conclusions With improved outcomes in metastatic cancer, more patients are encountered in practice. An aggressive surgical approach is warranted for extramedullary lesions, whereas caution is advised for intramedullary lesions. Postoperative functional decline is more likely due to systemic disease progression rather than surgery.

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