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  • Author or Editor: Georgios A. Zenonos x
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David T. Fernandes Cabral, Georgios A. Zenonos, Juan C. Fernandez-Miranda, Eric W. Wang and Paul A. Gardner

OBJECTIVE

Iatrogenic tumor seeding after open surgery for chordoma has been well described in the literature. The incidence and particularities related to endoscopic endonasal surgery (EES) have not been defined.

METHODS

The authors retrospectively reviewed their experience with EES for clival chordoma, focusing on cases with iatrogenic seeding. The clinical, radiographic, pathological, and molecular characterization data were reviewed.

RESULTS

Among 173 EESs performed for clival chordomas at the authors’ institution between April 2003 and May 2016, 2 cases complicated by iatrogenic seeding (incidence 1.15%) were identified. The first case was a 10-year-old boy, who presented 21 months after an EES for a multiply recurrent clival chordoma with a recurrence along the left inferior turbinate, distinct from a right petrous apex recurrence. Both appeared as a T2-hypertintense, T1-isointense, and heterogeneously enhancing lesion on MRI. Resection of the inferior turbinate recurrence and debulking of the petrous recurrence were both performed via a purely endoscopic endonasal approach. Unfortunately, the child died 2 years later due progression of disease at the primary site, but with no sign of progression at the seeded site. The second patient was a 79-year-old man with an MRI-incompatible pacemaker who presented 19 months after EES for his clival chordoma with a mass involving the floor of the left nasal cavity that was causing an oro-antral fistula. On CT imaging, this appeared as a homogeneously contrast-enhancing mass eroding the hard palate inferiorly, the nasal septum superiorly, and the nasal process of the maxilla, with extension into the subcutaneous tissue. This was also treated endoscopically (combined transnasal-transoral approach) with resection of the mass, and repair of the fistula by using a palatal and left lateral wall rotational flap. Adjuvant hypofractionated stereotactic CyberKnife radiotherapy was administered using 35 Gy in 5 fractions. No recurrence was appreciated endoscopically or on imaging at the patient’s last follow-up, 12 months after this last procedure. In both cases, pathological investigation of the original tumors revealed a fairly aggressive biology with 1p36 deletions, and high Ki-67 levels (10%–15%, and > 20%, respectively). The procedures were performed by a team of right-handed surgeons (otolaryngology and neurosurgery), using a 4-handed technique (in which the endoscope and suction are typically passed through the right nostril, and other instruments are passed through the left nostril without visualization).

CONCLUSIONS

Although uncommon, iatrogenic seeding occurs during EES for clival chordomas, probably because of decreased visualization during tumor removal combined with mucosal trauma and exposure of subepithelial elements (either inadvertently or because of mucosal flaps). In addition, tumors with more aggressive biology (1p36 deletions, elevated Ki-67, or both) are probably at a higher risk and require increased vigilance on surveillance imaging and endoscopy. Further prospective studies are warranted to evaluate the authors’ proposed strategies for decreasing the incidence of iatrogenic seeding after EES for chordomas.

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Georgios A. Zenonos, Juan C. Fernandez-Miranda, Debraj Mukherjee, Yue-Fang Chang, Klea Panayidou, Carl H. Snyderman, Eric W. Wang, Raja R. Seethala and Paul A. Gardner

OBJECTIVE

There are currently no reliable means to predict the wide variability in behavior of clival chordoma so as to guide clinical decision-making and patient education. Furthermore, there is no method of predicting a tumor’s response to radiation therapy.

METHODS

A molecular prognostication panel, consisting of fluorescence in situ hybridization (FISH) of the chromosomal loci 1p36 and 9p21, as well as immunohistochemistry for Ki-67, was prospectively evaluated in 105 clival chordoma samples from November 2007 to April 2016. The results were correlated with overall progression-free survival after surgery (PFSS), as well as progression-free survival after radiotherapy (PFSR).

RESULTS

Although Ki-67 and the percentages of tumor cells with 1q25 hyperploidy, 1p36 deletions, and homozygous 9p21 deletions were all found to be predictive of PFSS and PFSR in univariate analyses, only 1p36 deletions and homozygous 9p21 deletions were shown to be independently predictive in a multivariate analysis. Using a prognostication calculator formulated by a separate multivariate Cox model, two 1p36 deletion strata (0%–15% and > 15% deleted tumor cells) and three 9p21 homozygous deletion strata (0%–3%, 4%–24%, and ≥ 25% deleted tumor cells) accounted for a range of cumulative hazard ratios of 1 to 56.1 for PFSS and 1 to 75.6 for PFSR.

CONCLUSIONS

Homozygous 9p21 deletions and 1p36 deletions are independent prognostic factors in clival chordoma and can account for a wide spectrum of overall PFSS and PFSR. This panel can be used to guide management after resection of clival chordomas.

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Judith M. Wong, Allen L. Ho, Ning Lin, Georgios A. Zenonos, Christopher B. Martel, Kai Frerichs, Rose Du and William B. Gormley

Object

The care of patients with subarachnoid hemorrhage (SAH) has improved dramatically over the last decades. These gains are the result of improved microsurgical, endovascular, and medical management techniques. This intensive management subjects patients to multiple radiographic studies and thus increased radiation exposure. As greater understanding of the risks of radiation exposure develops, physicians must be better equipped to balance the need for optimal SAH management with the minimization of patient exposure to radiation from imaging studies. The goal in the current study was to determine if there is an opportunity for a reduction in radiation dose without a change in the quality of treatment in patients with SAH.

Methods

A retrospective chart review of all patients hospitalized for SAH at the Brigham and Women's Hospital in the period from January 1, 2009, to August 31, 2010, was performed. The authors calculated cumulative and imaging study–specific radiation doses, determined the time of day that imaging studies were performed, and surveyed neurosurgeons regarding issues surrounding imaging-related radiation exposure.

Results

The data for 77 patients were analyzed. The mean cumulative radiation dose during hospitalization was 2.76 Gy per patient (range 0.46–8.32 Gy). The mean radiation exposure from each CT, CT angiography (CTA), and angiography study was 0.08, 0.29, and 0.77 Gy (ranges 0.02–0.40, 0.15–0.99, and 0.11–4.36 Gy, respectively). Subgroup analysis of the top quartile of patients in terms of total radiation dose revealed a mean cumulative radiation dose of 4.78 Gy (range 3.42–8.32 Gy), mean cumulative number of CT and CTA scans of 14, and mean CT or CTA scan per day of 0.5 (maximum 0.8). Seventeen percent of the noncontrast head CT studies were performed just prior to morning rounds, more than double the 8% expected rate at random. Thirty-four percent of the repeat noncontrast head CTs did not show any change between scans, as documented on radiology reports. When surveyed, a majority of neurosurgeons incorrectly estimated the radiation dose typically received from CT, CTA, and angiography studies, and 65% asserted that radiation exposure is “not important” or only “somewhat important” when considering whether to order an imaging study.

Conclusions

Study findings suggested that patients with SAH have significant imaging-related exposure to radiation. The authors believe it is possible to continue the current improved outcomes in SAH with a significant reduction in radiation exposure from imaging studies. This analysis highlights the significance of accurate assessment of radiation exposure as a quality improvement target.

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Cristian Ferrareze Nunes, Stefan Lieber, Huy Q. Truong, Georgios Zenonos, Eric W. Wang, Carl H. Snyderman, Paul A. Gardner and Juan C. Fernandez-Miranda

OBJECTIVE

Pituitary adenomas may extend into the parapeduncular space by invading through the roof of the cavernous sinus. Currently, a transcranial approach is the preferred choice, with or without the combination of an endonasal approach. In this paper the authors present a novel surgical approach that takes advantage of the natural corridor provided by the tumor to further open the oculomotor triangle and resect tumor extension into the parapeduncular space.

METHODS

Six injected specimens were used to demonstrate in detail the surgical anatomy related to the approach. Four cases in which the proposed approach was used were retrospectively reviewed.

RESULTS

From a technical perspective, the first step involves accessing the superior compartment of the cavernous sinus. The interclinoid ligament should be identified and the dura forming the oculomotor triangle exposed. The oculomotor dural opening may be then extended posteriorly toward the posterior petroclinoidal ligament and inferolaterally toward the anterior petroclinoidal ligament. The oculomotor nerve should then be identified; in this series it was displaced superomedially in all 4 cases. The posterior communicating artery should also be identified to avoid its injury. In all 4 cases, the tumor invading the parapeduncular space was completely removed. There were no vascular injuries and only 1 patient had a partial oculomotor nerve palsy that completely resolved in 2 weeks.

CONCLUSIONS

The endoscopic endonasal transoculomotor approach is an original alternative for removal of tumor extension into the parapeduncular space in a single procedure. The surgical corridor is increased by opening the dura of the oculomotor triangle and by working below and lateral to the cisternal segment of the oculomotor nerve.