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Malte Ottenhausen, Kavelin Rumalla, Iyan Younus, Shlomo Minkowitz, Apostolos John Tsiouris and Theodore H. Schwartz

OBJECTIVE

Resection of supratentorial meningiomas is generally considered a low-risk procedure, but tumors involving the rolandic cortex present a unique challenge. The rate of motor function deterioration associated with resecting such tumors is not well described in the literature. Thus, the authors sought to report the rates and predictors of postoperative motor deficit following the resection of rolandic meningiomas to assist with patient counseling and surgical decision-making.

METHODS

An institution’s pathology database was screened for meningiomas removed between 2000 and 2017, and patients with neuroradiological evidence of rolandic involvement were identified. Parameters screened as potential predictors included patient age, sex, preoperative motor severity, tumor location, tumor origin (falx vs convexity), histological grade, FLAIR signal (T2-weighted MRI), venous involvement (T1-weighted MRI with contrast), intratumoral hemorrhage, embolization, and degree of resection (Simpson grade). Variables of interest included preoperative weakness and postoperative motor decline (novel or worsened permanent deficit). The SPSS univariate and bivariate analysis functions were used, and statistical significance was determined with alpha < 0.05.

RESULTS

In 89 patients who had undergone resection of convexity (80.9%) or parasagittal (19.1%) rolandic meningiomas, a postoperative motor decline occurred in 24.7%. Of 53 patients (59.6%) with preoperative motor deficits, 60.3% improved, 13.2% were unchanged, and 26.4% worsened following surgery. Among the 36 patients without preoperative deficits, 22.2% developed new weakness. Predictors of preoperative motor deficit included tumor size (41.6 vs 33.2 cm3, p = 0.040) and presence of FLAIR signal (69.8% vs 50.0%, p = 0.046). Predictors of postoperative motor decline were preoperative motor deficit (47.2% vs 22.2%, p = 0.017), minor (compared with severe) preoperative weakness (25.6% vs 21.4%, p < 0.001), and preoperative embolization (54.5% vs 20.5%, p = 0.014). Factors that trended toward significance included parafalcine tumor origin (41.2% vs 20.8% convexity, p = 0.08), significant venous involvement (44.4% vs 23.5% none, p = 0.09), and Simpson grade II+ (34.2% vs 17.6% grade I, p = 0.07).

CONCLUSIONS

Resection of rolandic area meningiomas carries a high rate of postoperative morbidity and deserves special preoperative planning. Large tumor size, peritumoral edema, preoperative embolization, parafalcine origin, and venous involvement may further increase the risk. Alternative surgical strategies, such as aggressive internal debulking, may prevent motor decline in a subset of high-risk patients.

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Mark M. Souweidane, Peter F. Morgenstern, Sungkwon Kang, Apostolos John Tsiouris and Jonathan Roth

Object

Fenestration of the floor of the third ventricle is vital to the success of endoscopic third ventriculostomy (ETV) in treating patients with noncommunicating hydrocephalus. A generous prepontine interval (PPI) is generally accepted as one anatomical feature that may affect the safety and functionality of ETV. Whether a diminished PPI influences the safety or success of ETV, however, has not been adequately assessed.

Methods

A review was conducted on the last 100 ETV procedures performed by the first author (M.M.S.). From archived preoperative MR imaging studies, the PPI was measured between the dorsum sellae and the basilar artery. For any patient with an interval of ≤1 mm, the technical and functional success of the procedure was recorded. Technical success was defined when a surgically created fenestration was accomplished without patient morbidity. Functional success was defined as the patient not needing any additional CSF diversionary procedure within 3 months after ETV.

Results

In the entire cohort, the PPI ranged from 0 to 9.5 mm (mean 3.2 mm). There were 15 procedures performed in patients with a PPI of ≤1 mm. In all 15 procedures, a fenestration of the tuber cinereum was accomplished without vascular injury or patient morbidity. The ETV was successful in 11 patients (73.3%). All 4 failures occurred in children who had surgery during infancy (mean age 11 months).

Conclusions

Patients with an obliterated or reduced PPI can safely undergo ETV. The functional success rate appears equivalent to historical controls. Most failures in this series may be attributed to other patient characteristics, namely young age at the time of ETV.

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Christoph P. Hofstetter, Benjamin Shin, Apostolos John Tsiouris, Eric Elowitz and Roger Härtl

Object

The paracoccygeal approach allows for instrumentation of L5/S1 and L4/5 by using a transsacral rod (AxiaLIF; TransS1, Inc.). The authors analyzed clinical and radiographic outcomes of 1- or 2-level AxiaLIF procedures with focus on durability of the construct.

Methods

This was a retrospective study of 38 consecutive patients who underwent either 1-level (32 patients) or 2-level (6 patients) AxiaLIF procedures at the authors' institution. The Oswestry Disability Index (minimum clinically important difference [MCID] ≥ 12) and visual analog scale ([VAS]; MCID ≥ 3) scores were collected. Disc height and Cobb angles were measured on pre- and postoperative radiographs. Bony fusion was determined on CT scans or flexion/extension radiographs.

Results

Implantation of a transsacral rod allowed for intraoperative distraction of the L5/S1 intervertebral space and resulted in increased segmental lordosis postoperatively. At a mean follow-up time of 26.2 ± 2.4 months, however, graft subsidence (1.9 mm) abolished partial correction of segmental lordosis. Moreover, subsidence of the construct reduced L5/S1 lordosis in patients with 1-level AxiaLIF by 3.2° and L4–S1 lordosis in patients with 2-level procedures by 10.1° compared with preoperative values (p < 0.01). Loss of segmental lordosis predicted failure to improve VAS scores for back pain in the patient cohort (p < 0.05). Overall, surgical intervention led to modest symptomatic improvement; only 26.3% of patients achieved an MCID of the Oswestry Disability Index and 50% of patients an MCID of the VAS score for back pain. At last follow-up, 71.9% of L5/S1 levels demonstrated bony fusion (1-level AxiaLIF 80.8%, 2-level AxiaLIF 33.3%; p < 0.05), whereas none of the L4/5 levels in 2-level AxiaLIF fused. Five constructs developed pseudarthrosis and required surgical revision.

Conclusions

The AxiaLIF procedure constitutes a minimally invasive technique for L5/S1 instrumentation, with low perioperative morbidity. However, the axial rod provides inadequate long-term anterior column support, which leads to subsidence and loss of segmental lordosis. Modification of the transsacral technique to allow for placement of a solid interposition graft may counteract subsidence of the construct.

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Konstantinos Margetis, Prajwal Rajappa, Apostolos John Tsiouris, Jeffrey P. Greenfield and Theodore H. Schwartz

OBJECT

A critical goal in neurosurgical oncology is maximizing the extent of tumor resection while minimizing the risk to normal white matter tracts. Frameless stereotaxy and white matter mapping are indispensable tools in this effort, but deep tumor margins may not be accurately defined because of the “brain shift” at the end of the operation. The authors investigated the safety and efficacy of a technique for marking the deep margins of intraaxial tumors with stereotactic injection of Indigo Carmine dye.

METHODS

Investigational New Drug study approval for a prospective study in adult patients with gliomas was obtained from the FDA (Investigational New Drug no. 112680). At surgery, 1–3 stereotactic injections of 0.01 ml of Indigo Carmine dye were performed through the initial bur holes into the deep tumor margins before elevation of the bone flap. White light microscopic resection was conducted in standard fashion by using frameless stereotactic navigation until the injected margins were identified. The resection of the injected tumor margins and the extent of resection of the whole tumor volume were determined by using postoperative volumetric MRI.

RESULTS

In total 17 injections were performed in 10 enrolled patients (6 male, 4 female), whose mean age was 49 years. For all patients, the injection points were identified intraoperatively and tumor was resected at these points. The staining pattern was reproducible; it was a sphere of stained tissue approximately 5 mm in diameter. A halo of stained tissue and a backflow of dye through the needle tract were also noted, but these were clearly distinct from the staining pattern of the injection point, which was vividly colored and demarcated. Postoperative MR images verified the resection of all injection points. The mean extent of resection of the tumor as a whole was 97.1%. For 1 patient, a brain abscess developed on postoperative Day 16 and needed additional surgical treatment.

CONCLUSIONS

Stereotactic injection of Indigo Carmine dye can be used to demarcate multiple deep tumor margins, which can be readily identified intraoperatively by using standard white light microscopy. This technique may enhance the accuracy of frameless stereotactic navigation and increase the extent of resection of intraaxial tumors.

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Malte Ottenhausen, Kavelin Rumalla, Iyan Younus, Shlomo Minkowitz, Apostolos John Tsiouris and Theodore H. Schwartz

OBJECTIVE

Resection of supratentorial meningiomas is generally considered a low-risk procedure, but tumors involving the rolandic cortex present a unique challenge. The rate of motor function deterioration associated with resecting such tumors is not well described in the literature. Thus, the authors sought to report the rates and predictors of postoperative motor deficit following the resection of rolandic meningiomas to assist with patient counseling and surgical decision-making.

METHODS

An institution’s pathology database was screened for meningiomas removed between 2000 and 2017, and patients with neuroradiological evidence of rolandic involvement were identified. Parameters screened as potential predictors included patient age, sex, preoperative motor severity, tumor location, tumor origin (falx vs convexity), histological grade, FLAIR signal (T2-weighted MRI), venous involvement (T1-weighted MRI with contrast), intratumoral hemorrhage, embolization, and degree of resection (Simpson grade). Variables of interest included preoperative weakness and postoperative motor decline (novel or worsened permanent deficit). The SPSS univariate and bivariate analysis functions were used, and statistical significance was determined with alpha < 0.05.

RESULTS

In 89 patients who had undergone resection of convexity (80.9%) or parasagittal (19.1%) rolandic meningiomas, a postoperative motor decline occurred in 24.7%. Of 53 patients (59.6%) with preoperative motor deficits, 60.3% improved, 13.2% were unchanged, and 26.4% worsened following surgery. Among the 36 patients without preoperative deficits, 22.2% developed new weakness. Predictors of preoperative motor deficit included tumor size (41.6 vs 33.2 cm3, p = 0.040) and presence of FLAIR signal (69.8% vs 50.0%, p = 0.046). Predictors of postoperative motor decline were preoperative motor deficit (47.2% vs 22.2%, p = 0.017), minor (compared with severe) preoperative weakness (25.6% vs 21.4%, p < 0.001), and preoperative embolization (54.5% vs 20.5%, p = 0.014). Factors that trended toward significance included parafalcine tumor origin (41.2% vs 20.8% convexity, p = 0.08), significant venous involvement (44.4% vs 23.5% none, p = 0.09), and Simpson grade II+ (34.2% vs 17.6% grade I, p = 0.07).

CONCLUSIONS

Resection of rolandic area meningiomas carries a high rate of postoperative morbidity and deserves special preoperative planning. Large tumor size, peritumoral edema, preoperative embolization, parafalcine origin, and venous involvement may further increase the risk. Alternative surgical strategies, such as aggressive internal debulking, may prevent motor decline in a subset of high-risk patients.

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Ranjodh Singh, William P. Cope, Zhiping Zhou, Michelle E. De Witt, John A. Boockvar and Apostolos J. Tsiouris

OBJECT

Isolated cortical vein thrombosis (ICVT) accounts for less than 1% of all cerebral infarctions. ICVT may cause irreversible parenchymal damage, rendering early and accurate diagnosis critical. This case series and literature review presents the clinical and radiological findings in 7 patients with ICVT, and highlights risk factors and imaging modalities that may be most beneficial in rendering an accurate and timely diagnosis.

METHODS

Patients with CT and MRI findings consistent with ICVT examined between January 2011 and June 2014 were included in this retrospective review.

RESULTS

Seven patients (5 females, 2 males), ranging in age from 11 months to 34 years, met the inclusion criteria. The most common clinical presentations were headaches (n = 4) and seizures (n = 3). The most common comorbidities noted in these patients were hypercoagulable states (n = 4) and intracranial hypotension (n = 3). Five patients had intraparenchymal involvement. CT suggested the correct diagnosis in 4 patients, and MRI confirmed the diagnosis in all 7 patients. All patients who received anticoagulation therapy (n = 5) experienced complete resolution of their symptoms.

CONCLUSIONS

The majority of these patients were adult females, consistent with published data. Seizures and headaches were the most common presenting symptoms. Hypercoagulable state and intracranial hypotension, both known risk factors for thrombosis, were the most commonly noted ICVT risk factors. Intraparenchymal involvement was prevalent in nearly all ICVT cases and presented as vasogenic edema, early intraparenchymal hemorrhage, or hemorrhagic venous infarction. Susceptibility-weighted imaging was the most sensitive imaging technique in diagnosing ICVT.

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Peter F. Morgenstern, Nathan Osbun, Theodore H. Schwartz, Jeffrey P. Greenfield, Apostolos John Tsiouris and Mark M. Souweidane

Object

Simultaneous endoscopic third ventriculostomy (ETV) and tumor biopsy is a widely accepted therapeutic and diagnostic procedure for patients with noncommunicating hydrocephalus secondary to a pineal region tumor. Multiple approaches have been advocated, including the use of a steerable fiberoptic or rigid lens endoscope via 1 or 2 trajectories. However, the optimal approach has not been established based on the individual anatomical characteristics of the patient.

Methods

A retrospective review of patients undergoing simultaneous ETV and tumor biopsy was undertaken. Preoperative MR images were examined to measure the width of the anterior third ventricle and maximal diameters of the tumor, Monro foramen (right), and massa intermedia. The distances between the tumor and massa intermedia, tumor and anterior commissure, midbrain and massa intermedia, and the dorsum sella and anterior commissure were also recorded. Single and dual trajectory approaches were compared using paired t-tests for each parameter.

Results

Over an 8-year interval, 15 patients underwent simultaneous ETV and tumor management. These patients ranged from 6 to 71 years of age (mean 36.7 years); 5 were younger than 18 years of age. Seven were treated using a dual trajectory approach, and 8 were treated using a single trajectory approach. All cases were completed without complications or the need for an additional CSF diversionary procedure within 6 months. The diagnostic yield at biopsy was 86.7%. There were no statistically significant differences between the single and dual trajectory groups for the measured parameters. However, the dual trajectory group demonstrated a larger anterior third ventricular diameter (1.43 vs 1.21 cm, p = 0.29). The single trajectory group trended toward a smaller tumor–anterior commissure interval (2.23 vs 2.51 cm, p = 0.24) and a larger dorsum sella–anterior commissure distance (1.67 vs 1.49 cm, p = 0.28).

Conclusions

These data confirm the safety and diagnostic efficacy of simultaneous ETV and biopsy for tumors of the pineal region. Although no statistically significant differences were seen in the authors' recorded measurements, several trends suggest a role for a tailored approach to selecting a single or dual trajectory approach when using a rigid endoscope.

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Nelson Moussazadeh, Vishaal Prabhu, Evan D. Bander, Ryan C. Cusic, Apostolos John Tsiouris, Vijay K. Anand and Theodore H. Schwartz

OBJECTIVE

The authors compared clinical and radiological outcomes after resection of midline craniopharyngiomas via an endoscopic endonasal approach (EEA) versus an open transcranial approach (TCA) at a single institution in a series in which the tumors were selected to be equally amenable to gross-total resection (GTR) with either approach.

METHODS

A single-institution retrospective review of previously untreated adult midline craniopharyngiomas was performed. Lesions were evaluated by 4 neurosurgeons blinded to the actual approach used to identify cases that were equally amenable to GTR using either an EEA or TCA. Radiological and clinical outcome data were assessed.

RESULTS

Twenty-six cases amenable to either approach were identified, 21 EEA and 5 TCA. Cases involving tumors that were resected via a TCA had a trend toward larger diameter (p = 0.10) but were otherwise equivalent in preoperative clinical and radiological characteristics. GTR was achieved in a greater proportion of cases removed with an EEA than a TCA (90% vs 40%, respectively; p = 0.009). Endoscopic resection was associated with superior visual restoration (63% vs 0%; p < 0.05), a decreased incidence of recurrence (p < 0.001), lower increase in FLAIR signal postoperatively (−0.16 ± 4.6 cm3 vs 14.4 ± 14.0 cm3; p < 0.001), and fewer complications (20% vs 80% of patients; p < 0.001). Significantly more TCA patients suffered postoperative cognitive loss (80% vs 0; p < 0.0001).

CONCLUSIONS

An EEA is a safe and effective approach to suprasellar craniopharyngiomas amenable to GTR. For this select group of cases, the EEA may provide higher rates of GTR and visual improvement with fewer complications compared with a TCA.

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Aikaterini Patrona, Kunal S. Patel, Evan D. Bander, Alpesh Mehta, Apostolos John Tsiouris, Vijay K. Anand and Theodore H. Schwartz

OBJECTIVE

Surgery within the cavernous sinus (CS) remains a controversial topic because of the delicate and complex anatomy. The risk also varies with tumor consistency. Softer tumors such as pituitary adenomas are more likely to be surgically treated, while firm tumors such as meningiomas are often treated with radiosurgery. However, a wide range of pathologies that can involve the CS are amenable to surgery. The authors describe and analyze their results using endonasal endoscopic “medial-to-lateral” approaches for nonadenomatous, nonmeningeal tumors, in relation to the degree of invasion within the CS.

METHODS

A prospectively acquired database of consecutive endoscopic approaches for tumors with verified intraoperative CS invasion was reviewed. Pituitary adenomas and meningiomas were excluded. Degree of invasion of the CS was classified using the Knosp-Steiner (KS) grading system as well as the percentage of cavernous carotid artery (CCA) encasement. Extent of resection of the entire tumor and of the CS component was assessed by independent neuroradiologists using volumetric measurements of the pre- and postoperative MRI studies. Demographic data and complications were noted.

RESULTS

Fifteen patients (mean age 51.1 years who received endoscopic surgery between 2007 and 2013 met the selection criteria. There were 11 malignant tumors, including chordoma, chondrosarcoma, hemangiopericytoma, lymphoma, and metastatic cancer, and 4 benign tumors, including 3 cavernous hemangiomas and 1 dermoid. All cases were discussed before treatment in a tumor board. Adjuvant treatment options included chemotherapy and radiotherapy. The mean pre- and postoperative tumor volumes were 12.74 ml and 3.86 ml. Gross-total resection (GTR; ie, resection greater than 95%) was the goal in 13 cases and was achieved in 6 patients (46%) while in addition 5 patients had a greater than 80% resection. Gross-total resection in the CS was accomplished in 55% of the tumors with KS Grades 1–2 and in 16.6% of the tumors with KS grades 3–4, respectively. Likewise, GTR was accomplished in 55% of the tumors with CCA encasement under 75% and in 14.3% of the lesions with CCA encasement over 75%, irrespective of tumor volume and underlying pathology. There were 18 preexisting cranial neuropathies involving cranial nerves III–VI, of which 9 fully resolved, 4 improved, and 3 remained unchanged; 2 of these worsened with tumor recurrence. Surgical complications included 1 transient new cranial nerve VI palsy associated with Horner's syndrome and 1 case of panhypopituitarism. There were no postoperative CSF leaks and no infections. The mean extended follow-up was 34.4 months.

CONCLUSIONS

Endonasal endoscopic approaches can play a role in the management of nonmeningeal, nonadenomatous tumors invading the CS, either through biopsy, debulking, or GTR. An advantage of this method is the relief of preexisting cranial neuropathies with low risk for new neurological deficit. Extent of resection within the CS varies with KS grade and degree of carotid encasement irrespective of the underlying pathology. The goals of surgery should be clearly established preoperatively in consultation with radiation and medical oncologists.

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Peter F. Morgenstern, Zhiping Zhou, Eva Wembacher-Schröder, Vincent Cina, Apostolos John Tsiouris and Mark M. Souweidane

OBJECTIVE

Convection-enhanced delivery (CED) has been explored as a therapeutic strategy for diffuse intrinsic pontine glioma (DIPG). Variables that may affect tolerance include infusate volume, infusion rate, catheter trajectory, and target position. Supratentorial approaches for catheter placement and infusate distribution patterns may conflict with corticospinal tracts (CSTs). The clinical relevance of these anatomical constraints has not been described. The authors report their experience using CED in the brainstem as it relates to anatomical CST conflict and association with clinical tolerance.

METHODS

In a phase I clinical trial of CED for DIPG (clinical trial registration no. NCT01502917, clinicaltrials.gov), a flexible infusion catheter was placed with MRI guidance for infusion of 124I-8H9, a radioimmunotherapeutic agent. Intra- and postprocedural MR images were analyzed to identify catheter trajectories and changes in T2-weighted signal intensity to approximate volume of distribution (Vd). Intersection of CST by the catheter and overlap between Vd and CST were recorded and their correlation with motor deficits was evaluated.

RESULTS

Thirty-one patients with a mean age of 7.6 years (range 3.2–18 years) underwent 39 catheter insertions for CED between 2012 and 2017. Thirty catheter insertions had tractography data available for analysis. The mean trajectory length was 105.5 mm (range 92.7–121.6 mm). The mean number of intersections of CST by catheter was 2.2 (range 0–3) and the mean intersecting length was 18.9 mm (range 0–44.2 mm). The first 9 infusions in the highest dose level (range 3.84–4.54 ml infusate) were analyzed for Vd overlap with CST. In this group, the mean age was 7.6 years (range 5.8–10.3 years), the mean trajectory length was 109.5 mm (range 102.6–122.3 mm), and the mean overlap between Vd and CST was 5.5 cm3. For catheter placement–related adverse events, 1 patient (3%) had worsening of a contralateral facial nerve palsy following the procedure with two CST intersections, an intersecting distance of 31.7 mm, and an overlap between Vd and CST of 3.64 cm3. For infusion-related adverse events, transient postinfusion deficits were noted in 3 patients in the highest dose level, with a mean number of 2 intersections of CST by catheter, mean intersecting length of 12.9 mm, and mean overlap between Vd and CST of 6.3 cm3.

CONCLUSIONS

A supratentorial approach to the brainstem crossing the CST resulted in one worsened neurological deficit. There does not appear to be a significant risk requiring avoidance of dominant motor fiber tracts with catheter trajectory planning. There was no correlation between Vd–CST overlap and neurological adverse events in this cohort.

Clinical trial registration no.: NCT01502917 (clinicaltrials.gov)