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Double-barrel STA-MCA bypass and partial trapping of a ruptured mycotic MCA aneurysm with flash fluorescence technique

Christopher S. Graffeo, Visish M. Srinivasan, Tyler S. Cole, and Michael T. Lawton

Mycotic brain aneurysms are rare and unusual cerebrovascular lesions arising from septic emboli that degrade the elastic lamina and vessel wall of intracranial arteries, which results in pathologic dilatation. Mycotic aneurysms are nonsaccular lesions that are not often suitable for clipping and instead require bypass, trapping, and flow reversal. This case demonstrates the use of indocyanine green “flash fluorescence” to identify the cortical distribution supplied by an aneurysm’s outflow, facilitating safe treatment with a double-barrel extracranial-intracranial bypass and partial trapping and conversion of a deep bypass to a superficial one.

The video can be found here: https://stream.cadmore.media/r10.3171/2021.10.FOCVID21163

Free access

Complex cranial surgery and the future of open cerebrovascular training

Christopher S. Graffeo, Michael J. Link, and Michael T. Lawton

Free access

Letter to the Editor. Restraint is not the better part of valor

Tyler S. Cole and Robert F. Spetzler

Full access

Neurosurgery and the rise of academic social media: what neurosurgeons should know

Joseph R. Linzey, Christopher S. Graffeo, Justin Z. Wang, Ali S. Haider, and Naif M. Alotaibi

Restricted access

Expanding the reach of the trans–middle cerebellar peduncle approach: pontine cavernous malformations, tissue transgression beyond the safe entry zone, and the invisible triangle

Christopher S. Graffeo, Visish M. Srinivasan, Lea Scherschinski, Dimitri Benner, Katherine Karahalios, Diego A. Devia, Joshua S. Catapano, and Michael T. Lawton

OBJECTIVE

In the authors’ microsurgical experience, the trans–middle cerebellar peduncle (MCP) approach to the lateral and central pons has been the most common approach to brainstem cavernous malformations (BSCMs). This approach through a well-tolerated safe entry zone (SEZ) allows a wide vertical or posterior trajectory, reaching pontine lesions extending into the midbrain, medulla, and pontine tegmentum. Better understanding of the relationships among lesion location, surgical trajectory, and long-term clinical outcomes could determine areas of safe passage.

METHODS

A single-surgeon cohort study of all primary trans-MCP BSCM resections was conducted from July 1, 2017, to June 30, 2021. Preoperative and postoperative MR images were independently reviewed by 3 investigators blinded to the intervention, using a standardized rubric to define BSCM regions of interest (ROIs) involved with a lesion or microsurgical tract. Statistical testing, including the chi-square test with the Bonferroni correction, logistic regression, and structural equation modeling, was performed to analyze relationships between ROIs and clinical outcomes.

RESULTS

Thirty-one patients underwent primary trans-MCP BSCM resection during the study period. The median age was 50 years (IQR 24–49 years); 19 (61%) patients were female, and 12 (39%) were male. Seven (23%) patients had familial cavernous malformation syndromes. The median follow-up was 9 months (range 6–37 months). At the last follow-up, composite neurological outcomes were favorable: 22 (71%) patients had 0 (n = 12, 39%) or 1 (n = 10, 32%) major persistent deficit, 5 patients (16%) had 2 deficits, 2 (7%) had 3 deficits, and 1 patient each (3%) had 4 or 6 deficits. Unfavorable composite outcomes were significantly associated with lesions (OR 7.14, p = 0.04) or surgical tracts (OR 12.18, p < 0.001) extending from the superior cerebellar peduncle (SCP) into the contralateral medial midbrain. The ipsilateral dorsal pons was the most frequently implicated ROI involving a surgical tract and the development of new postoperative deficits. This region involved the rhomboid pontine territory and transgression of the pontine tegmentum (OR 7.53, p < 0.001). Structural equation modeling supported medial midbrain and pontine tegmentum transgression as the primary drivers of morbidity.

CONCLUSIONS

Trans-MCP resection is a safe and effective treatment for BSCMs, including lesions with marked superior or inferior ipsilateral extension. Two trajectories are associated with increased neurological risk: first, a superomedial trajectory to lesions extending into the midbrain that transgresses the SCP, its decussation, or both; and second, a posteromedial trajectory to lesions extending into the pontine tegmentum. The corticospinal tract, SCP, and pontine tegmentum form an invisible triangle within the pontine white matter tolerant of transgression. When the surgeon works within this triangle, most deep pontine BSCMs, including large lesions, those with contralateral or posterior extension, and others extending into the midbrain and medulla, can be resected safely with the trans-MCP approach.

Full access

Pediatric ganglioglioma of the brainstem and cervicomedullary junction: a retrospective cohort study

Soliman Oushy, Avital Perry, Christopher S. Graffeo, Aditya Raghunathan, Lucas P. Carlstrom, and David J. Daniels

OBJECTIVE

Ganglioglioma is a low-grade central nervous system neoplasm with a pediatric predominance, accounting for 10% of all brain tumors in children. Gangliogliomas of the cervicomedullary junction (GGCMJs) and brainstem (GGBSs) present a host of management challenges, including a significant risk of surgical morbidity. At present, understanding of the prognostic factors—including BRAF V600E status—is incomplete. Here, the authors report a single-institution GGCMJ and GGBS experience and review the pertinent literature.

METHODS

A prospectively maintained neurosurgical database at a large tertiary care academic referral center was retrospectively queried for cases of GGCMJ pathologically confirmed in the period from 1995 to 2015; appropriate cases were defined by diagnosis codes and keywords. Secondary supplemental chart review was conducted to confirm or capture relevant data. The primary study outcome was treatment failure as defined by evidence of radiographic recurrence or progression and/or clinical or functional decline. A review of the literature was conducted as well.

RESULTS

Five neurosurgically managed GGBS patients were identified, and the neoplasms in 4 were classified as GGCMJ. All 5 patients were younger than 18 years old (median 15 years, range 4–16 years) and 3 (60%) were female. One patient underwent gross-total resection, 2 underwent aggressive subtotal resection (STR), and 2 underwent stereotactic biopsy only. All patients who had undergone STR or biopsy required repeat resection for tumor control or progression. Progressive disease was treated with radiotherapy in 2 patients, chemotherapy in 2, and chemoradiotherapy alone in 1. Immunostaining for BRAF V600E was positive in 3 patients (60%). All 5 patients experienced at least one major complication, including wound infection, foot drop, hemiparesis, quadriparesis, cranial neuropathy, C2–3 subluxation, syringomyelia, hydrocephalus, aspiration, and coma. Overall mortality was 20%, with 1 death observed over 11 years of follow-up.

CONCLUSIONS

GGBS and GGCMJ are rare, benign posterior fossa tumors that carry significant perioperative morbidity. Contemporary management strategies are heterogeneous and include combinations of resection, radiotherapy, and chemotherapy. The BRAF V600E mutation is frequently observed in GGBS and GGCMJ and appears to have both prognostic and therapeutic significance with targeted biological agents.

Free access

Extraordinary case presentations in pediatric pituitary adenoma: report of 6 cases

Jenna Meyer, Avital Perry, Soliman Oushy, Christopher S. Graffeo, Lucas P. Carlstrom, and Fredric B. Meyer

Pediatric pituitary adenomas (PPAs) are rare neoplasms with a propensity for unusual presentations and an aggressive clinical course. Here, the authors describe 6 highly atypical PPAs to highlight this tendency and discuss unexpected management challenges.

A 14-year-old girl presented with acute hemiparesis and aphasia. MRI revealed a pituitary macroadenoma causing internal carotid artery invasion/obliteration without acute apoplexy, which was treated via emergent transsphenoidal resection (TSR). Another 14-year-old girl developed precocious galactorrhea due to macroprolactinoma, which was medically managed. Several years later, she re-presented with acute, severe, bitemporal hemianopia during her third trimester of pregnancy, requiring emergent induction of labor followed by TSR. A 13-year-old boy was incidentally diagnosed with a prolactinoma after routine orthodontic radiographs captured a subtly abnormal sella. An 18-year-old male self-diagnosed pituitary gigantism through a school report on pituitary disease. A 17-year-old boy was diagnosed with Cushing disease by his basketball coach, a former endocrinologist. A 12-year-old girl with growth arrest and weight gain was diagnosed with Cushing disease, which was initially treated via TSR but subsequently recurred and ultimately required 12 operations, 5 radiation treatments involving 3 modalities, bilateral adrenalectomy, and chemotherapy. Despite these efforts, she ultimately died from pituitary carcinoma.

Open access

Nocardia farcinica pituitary abscess in an immunocompetent patient: illustrative case

Kristen M. Scheitler, Megan M. J. Bauman, Lucas P. Carlstrom, Christopher S. Graffeo, and Fredric B. Meyer

BACKGROUND

Pituitary abscess is a rare clinical entity, typically precipitated by Staphylococcus, Pseudomonas, or Aspergillus infection. Although Nocardia species–associated central nervous system abscesses have been documented in immunocompromised patients, no case of Nocardia pituitary abscesses has been previously reported.

OBSERVATIONS

A 44-year-old man presented with hemoptysis and was found to have a cavitary right lung nodule, which was presumed histoplasmosis, prompting antifungal treatment. Several months later, he developed panhypopituitarism. Magnetic resonance imaging identified a pituitary mass, which subsequently underwent transsphenoidal endoscopic biopsy. Infectious workup was negative, and the patient was discharged on intravenous ertapenem therapy. Over several months, he developed progressive headaches, and updated imaging confirmed interval enlargement of the mass with new cavernous sinus invasion. He underwent repeat endoscopic biopsy, which yielded positive cultures for Nocardia farcinica and prompted successful treatment with trimethoprim-sulfamethoxazole and linezolid.

LESSONS

The current study highlights a previously unreported clinical entity, the first pituitary abscess attributable to Nocardia sp. or N. farcinica, which arose in a young, immunocompetent individual. Although rare, atypical infections represent an important component in the differential diagnosis for sellar mass lesions.

Free access

Novel rodent model for simulation of sylvian fissure dissection and cerebrovascular bypass under subarachnoid hemorrhage conditions: technical note and timing study

Avital Perry, Christopher S. Graffeo, Lucas P. Carlstrom, William J. Anding, Michael J. Link, and Leonardo Rangel-Castilla

OBJECTIVE

Sylvian fissure dissection following subarachnoid hemorrhage (SAH) is a challenging but fundamental skill in microneurosurgery, and one that has become increasingly difficult to develop during residency, given the overarching management trends. The authors describe a novel rodent model for simulation of sylvian fissure dissection and cerebrovascular bypass under SAH conditions.

METHODS

A standardized microvascular anastomosis model comprising rat femoral arteries and veins was used for the experimental framework. In the experimental protocol, following exposure and skeletonization of the vessels, extensive, superficial (1- to 2-mm) soft-tissue debridement was conducted and followed by wound closure and delayed reexploration at intervals of 7, 14, and 28 days. Two residents dissected 1 rat each per time point (n = 6 rats), completing vessel skeletonization followed by end-to-end artery/vein anastomoses. Videos were reviewed postprocedure to assess scar score and relative difficulty of dissection by blinded raters using 4-point Likert scales.

RESULTS

At all time points, vessels were markedly invested in friable scar, and exposure was subjectively assessed as a reasonable surrogate for sylvian fissure dissection under SAH conditions. Scar score and relative difficulty of dissection both indicated 14 days as the most challenging time point.

CONCLUSIONS

The authors’ experimental model of femoral vessel skeletonization, circumferential superficial soft-tissue injury, and delayed reexploration provides a novel approximation of sylvian fissure dissection and cerebrovascular bypass under SAH conditions. The optimal reexploration interval appears to be 7–14 days. To the authors’ knowledge, this is the first model of SAH simulation for microsurgical training, particularly in a live animal system.

Open access

Posterior petrosectomy for resection of pontine cavernous malformation

Avital Perry, Thomas J. Sorenson, Christopher S. Graffeo, Colin L. Driscoll, and Michael J. Link

Cavernous malformations (CMs) are low-pressure, focal, vascular lesions that may occur within the brainstem and require treatment, which can be a substantial challenge. Herein, we demonstrate the surgical resection of a hemorrhaged brainstem CM through a posterior petrosectomy approach. After dissection of the overlying vascular and meningeal structures, a safe entry zone into the brainstem is identified based on local anatomy and intraoperative neuronavigation. Small ultrasound probes can also be useful for obtaining real-time intraoperative feedback. The CM is internally debulked and resected in a piecemeal fashion through an opening smaller than the CM itself. As brainstem CMs are challenging lesions, knowledge of several surgical nuances and adoption of careful microsurgical techniques are requisite for success.

The video can be found here: https://youtu.be/szB6YpzkuCo.