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Jorge E. Alvernia and Marc P. Sindou

Object. To understand the cause and prevention of postoperative ischemic and/or venous parenchymal infarcts after intracranial meningioma resection, the authors describe the value of neuroimaging in predicting the surgical plane of cleavage.

Methods. A prospective study of 100 meningiomas was performed, in which tumor size, absence or presence of peritumoral edema, tumor—parenchyma interface, and types of arterial vascularization (that is, dural—meningeal, pial—cortical, or mixed) were correlated with the type of dissection plane (extrapial, subpial, or mixed) encountered at surgery. A direct correlation was found between the tumor size identified on T1-weighted magnetic resonance (MR) imaging sequences and the degree of subpial (nonextrapial) surgical plane of cleavage (p < 0.00001). A similar correlation was found with the grade of peritumoral edema identified on preoperative computerized tomography (CT) scanning (p < 0.0001) or T2-weighted MR imaging sequences (p < 0.00001) and tumor pial vascularization as seen on angiography (p < 0.0001). Nevertheless, the tumor—parenchyma interface on preoperative T2-weighted MR imaging sequences was not predictive of the surgical plane (p > 0.5). The worst clinical outcome was found in the tumors located in eloquent areas and in which a subpial plane was encountered at surgery (p = 0.03).

Conclusions. Peritumoral edema on preoperative CT and MR studies and tumor pial vascularization as seen on selective angiography can be used to predict the surgical plane of cleavage in meningiomas. The association between tumor size and a subpial surgical plane may be explained by a more pial vascularization seen on angiography. Meningiomas with a location in eloquent cortex and a subpial dissection plane should be considered a high-risk group.

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Marc P. Sindou and Jorge E. Alvernia

Object

Radical removal of meningiomas involving the major dural sinuses remains controversial. In particular, whether the fragment invading the sinus must be resected and whether the venous system must be reconstructed continue to be issues of debate. In this paper the authors studied the effects, in terms of tumor recurrence rate as well as morbidity and mortality rates, of complete lesion removal including the invaded portion of the sinus and the consequences of restoring or not restoring the venous circulation.

Methods

The study consisted of 100 consecutive patients who had undergone surgery for meningiomas originating at the superior sagittal sinus in 92, the transverse sinus in five, and the confluence of sinuses in three. A simplified classification scheme based on the degree of sinus involvement was applied: Type I, lesion attachment to the outer surface of the sinus wall; Type II, tumor fragment inside the lateral recess; Type III, invasion of the ipsilateral wall; Type IV, invasion of the lateral wall and roof; and Types V and VI, complete sinus occlusion with or without one wall free, respectively. Lesions with Type I invasion were treated by peeling the outer layer of the sinus wall. In cases of sinus invasion Types II to VI, two strategies were used: a nonreconstructive (coagulation of the residual fragment or global resection) and a reconstructive one (suture, patch, or bypass). Gross-total tumor removal was achieved in 93% of cases, and sinus reconstruction was attempted in 45 (65%) of the 69 cases with wall and lumen invasion. The recurrence rate in the study overall was 4%, with a follow-up period from 3 to 23 years (mean 8 years). The mortality rate was 3%, all cases due to brain swelling after en bloc resection of a Type VI meningioma without venous restoration. Eight patients—seven of whom harbored a lesion in the middle third portion of the superior sagittal sinus—had permanent neurological aggravation, likely due to local venous infarction. Six of these patients had not undergone a venous repair procedure.

Conclusions

The relatively low recurrence rate in the present study (4%) favors attempts at complete tumor removal, including the portion invading the sinus. The subgroup of patients without venous reconstruction displayed statistically significant clinical deterioration after surgery compared with the other subgroups (p = 0.02). According to this result, venous flow restoration seems justified when not too risky.

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Jorge E. Alvernia, Nguyen D. Dang, and Marc P. Sindou

Object

Convexity meningiomas are expected to have a low recurrence rate given their classically “easy resectability.” Nonetheless, recurrence can occur. Factors playing a role in their recurrence are analyzed here, including the extent of resection and tumor histological type, among others, with a special emphasis on the cleavage plane.

Methods

The authors reviewed 100 cases of convexity meningiomas surgically treated between 1987 and 2001 with a median follow-up of 86 months (range 2–16 years). Preoperative and postoperative functional status, Simpson resection grade, histological type, and intraoperative surgical plane with pial vessel invasion were studied and correlated with the recurrence rate.

Results

The average tumor size was 3.6 ± 0.4 cm. The pre- and postoperative Karnofsky Performance Scale scores were 92.6 ± 4.6 and 97.9 ± 2.2, respectively. Ninety-five lesions were benign (WHO Grade I) and 5 were atypical (WHO Grade II). Ninety-one and 9 tumors were subjected to Simpson Grade 1 and 3 resections (three Grade 3a and six Grade 3b), respectively. Surgical deaths did not occur. After a mean follow-up of 7.2 years, 4 meningiomas recurred; 2 (2.2%) after Simpson Grade 1 resections and 2 after Simpson Grade 3 (3a and 3b) resections (22.2%; p = 0.0034). When just the subgroup of Simpson Grade 1/WHO Grade I was studied, the recurrence rate decreased to 1.2% (1 of 86 cases). The recurrence of WHO Grade I tumors was higher in the subpial group than in the extrapial group (p = 0.025). No difference in recurrence according to the cleavage plane was seen in the WHO Grade II subgroup (p = 0.361). As for the subpial group, no difference in recurrence was noted between the WHO Grade I and II subgroups (p = 0.608). Importantly, however, the extrapial subgroup of WHO Grade II lesions had a higher recurrence rate compared with its counterpart in the WHO Grade I subgroup (p = 0.005).

Conclusions

Pial and vascular invasion affect the recurrence rate in convexity meningioma surgery. The recurrence rate of WHO Grade I tumors was higher among those with a subpial plane of dissection than among those with an extrapial one. Histological type did not determine the degree of pial invasion in WHO Grade I and II lesions.

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Jason H. Maley, Jorge E. Alvernia, Edison P. Valle, and Donald Richardson

Intermittent explosive disorder (IED) is characterized by a dysfunction in the greater limbic system leading an individual to experience sudden aggressive behavior with little or no environmental perturbation. This report describes a procedure for the treatment of IED in a 19-year-old woman with a history of IED, having had episodes of severe violent attacks against family, dating to early childhood. Due to the severity and intractability of the illness, deep brain stimulation was performed, targeting the orbitofrontal projections to the hypothalamus. The patient's history and the procedure, management, and rationale are described in detail.

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Jorge E. Alvernia, Daniel G. Spomar, and William C. Olivero

Object

Gamma Knife surgery has recently been used to treat patients with cluster headaches. Both the trigeminal nerve root and the pterygopalatine ganglion (PPG) have been targeted. However, there are no clear-cut anatomical landmarks on computed tomography (CT) scans or magnetic resonance images that accurately identify the PPG. Therefore, the authors performed microsurgical dissections on latex-injected cadaver heads to expose the PPG and correlated the findings with thin-slice axial CT scans obtained in the same heads to determine how best to target the PPG.

Methods

Three cadaver heads (five sides) previously injected with colored latex were dissected using skull base approaches and microsurgical techniques to identify the PPG and surrounding structures. Measurements were then made to different osseous anatomical landmarks such as the foramen rotundum, vidian canal, and so on. The PPG was marked with a radiopaque marker and thin-slice CT scans were obtained in the cadaver heads to develop some correlates that could be used to identify where the PPG is located on CT scans.

Results

The PPG was clearly identified in all specimens and had a mean diameter of 3.58 ± 0.6 mm. The PPG was always located in the same plane (lateral and vertical) as the vidian canal and was located on average 2.7 ± 0.3 mm from the end of the canal. The vidian canal was clearly identified on coronal CT scans and had a diameter of 3.05 mm.

Conclusions

There was a clear and constant relationship between the PPG and vidian canal. The vidian canal is easily identified on coronal CT scans and can be used as a landmark to target the PPG with the Gamma Knife.

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Roberto C. Heros

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Jorge E. Alvernia, Miguel Enrique Berbeo Calderón, Jorge Cespedes, John Vargas, Matthew Grady, Luis C. Cadavid, Enrique Osorio Fonseca, and Adolfo Cumplido Posada

Ernesto Bustamante Zuleta (1922–2021) was an impactful Colombian neurosurgeon whose legacy is inextricably linked with the development of the neurosurgery specialty in Colombia. His detail-oriented approach to treatment complemented his reputation for mastery of the neurosciences. Never simply confined to the operating theater, this calm and considerate physician felt compelled to teach during his entire career. The result of his teaching made a lasting imprint on an entire generation of neurosurgeons who subsequently established a high standard of neurosurgical care in Colombia. A true pioneer, Bustamante comprehensively engaged in his field, from founding the country’s first residency program in neurosurgery to successfully implementing technology in his procedures, performing many of Colombia’s first neurosurgical interventions, and publishing extensively across various categories of medical science. This historical reflection highlights his enduring contributions to the field and considers his legacy through the witness testimony of many of his students and collaborators. The hope is that his contributions may be acknowledged in full, as he was a reserved person who never boasted of his own accomplishments. The authors also hope that those who did not have the opportunity to know him would be informed by the historical context of the development of Colombian neurosurgery and inspired by his conviction and altruism.

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Enrique Osorio Fonseca, Luis C. Cadavid, Jorge Cespedes, John Vargas, Matthew Grady, L. Fernando Gonzalez, Miguel Enrique Berbeo, Edgar G. Ordóñez-Mora, Edgar G. Ordóñez-Rubiano, and Jorge E. Alvernia

The history of Colombian neurosurgery is a collective legacy of neurosurgeon-scientists, scholars, teachers, innovators, and researchers. Anchored in the country’s foundational values of self-determination and adaptability, these pioneers emerged from the Spanish colonial medical tradition and forged surgical alliances abroad. From the time of Colombian independence until the end of World War I, exchanges with the French medical tradition produced an emphasis on anatomical and systematic approaches to the emerging field of neurosurgery. The onset of American neurosurgical expertise in the 1930s led to a new period of exchange, wherein technological innovations were added to the Colombian neurosurgical repertoire. This diversity of influences culminated in the 1950s with the establishment of Colombia’s first in-country neurosurgery residency program. A select group of avant-garde neurosurgeons from this period expanded the domestic opportunities for patients and practitioners alike. Today, the system counts 10 recognized neurosurgery residency programs and over 500 neurosurgeons within Colombia. Although the successes of specific individuals and innovations were considered, the primary purpose of this historical survey was to glean relevant lessons from the past that can inform present challenges, inspire new opportunities, and identify professional and societal goals for the future of neurosurgical practice and specialization.

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Jorge E. Alvernia, Emile Simon, Krishnakant Khandelwal, Cara D. Ramos, Eddie Perkins, Patrick Kim, Patrick Mertens, Raffaella Messina, Gustavo Luzardo, and Orlando Diaz

OBJECTIVE

The aim of this paper was to identify and characterize all the segmental radiculomedullary arteries (RMAs) that supply the thoracic and lumbar spinal cord.

METHODS

All RMAs from T4 to L5 were studied systematically in 25 cadaveric specimens. The RMA with the greatest diameter in each specimen was termed the artery of Adamkiewicz (AKA). Other supporting RMAs were also identified and characterized.

RESULTS

A total of 27 AKAs were found in 25 specimens. Twenty-two AKAs (81%) originated from a left thoracic or a left lumbar radicular branch, and 5 (19%) arose from the right. Two specimens (8%) had two AKAs each: one specimen with two AKAs on the left side and the other specimen with one AKA on each side. Eight cadaveric specimens (32%) had 10 additional RMAs; among those, a single additional RMA was found in 6 specimens (75%), and 2 additional RMAs were found in each of the remaining 2 specimens (25%). Of those specimens with a single additional RMA, the supporting RMA was ipsilateral to the AKA in 5 specimens (83%) and contralateral in only 1 specimen (17%). The specimens containing 2 additional RMAs were all (100%) ipsilateral to their respective AKAs.

CONCLUSIONS

The segmental RMAs supplying the thoracic and lumbar spinal cord can be unilateral, bilateral, or multiple. Multiple AKAs or additional RMAs supplying a single anterior spinal artery are common and should be considered when dealing with the spinal cord at the thoracolumbar level.