History and evolution of surgical treatment for spasticity: a journey from neurotomy to selective dorsal rhizotomy.

The evolution of neurosurgical approaches to spasticity spans centuries, marked by key milestones and innovative practitioners. Probable ancient descriptions of spasmodic conditions were first classified as spasticity in the 19th century through the interventions of Dr. William John Little on patients with cerebral palsy. The late 19th century witnessed pioneering efforts by surgeons such as Dr. Charles Loomis Dana, who explored neurotomies, and Dr. Charles Sherrington, who proposed dorsal rhizotomy to address spasticity. Dorsal rhizotomy rose to prominence under the expertise of Dr. Otfrid Foerster but saw a decline in the 1920s due to emerging alternative procedures and associated complications. The mid-20th century saw a shift toward myelotomy but the revival of dorsal rhizotomy under Dr. Claude Gros' selective approach and Dr. Marc Sindou's dorsal root entry zone (DREZ) lesioning. In the late 1970s, Dr. Victor Fasano introduced functional dorsal rhizotomy, incorporating electrophysiological evaluations. Dr. Warwick Peacock and Dr. Leila Arens further modified selective dorsal rhizotomy, focusing on approaches at the cauda equina level. Later, baclofen delivered intrathecally via an implanted programmable pump emerged as a promising alternative around the late 1980s, pioneered by Richard Penn and Jeffrey Kroin and then led by A. Leland Albright. Moreover, intraventricular baclofen has also been tried in this matter. The evolution of these neurosurgical interventions highlights the dynamic nature of medical progress, with each era building upon and refining the work of significant individuals, ultimately contributing to successful outcomes in the management of spasticity.

Risk of Injury to Retroperitoneal Structures in Prone and Lateral Decubitus Transpsoas Approaches to Lumbar Interbody Fusion: A Pilot Cadaveric Anatomical Study.

Introduction The retroperitoneal approach for lateral lumbar interbody fusion (LLIF) originally described an initial posterolateral fascial incision enabling finger dissection from behind the peritoneum and guidance of instruments through a second direct-lateral fascial incision. It has since become common for single direct-lateral incisional access to the retroperitoneum. This study attempted to quantify the distance of the peritoneum from posterior landmarks in the space, assess the risk of peritoneal violation in each access trajectory (i.e., posterolateral versus direct lateral retroperitoneal dissection), and determine whether there are differences based on patient position (prone versus lateral decubitus). Methods In three prone cadaveric torsos, Steinman pins were percutaneously placed mid-disc at each level L2-5 bilaterally (for a total of 18 prone approaches). Open dissections exposed the retroperitoneum including the quadratus lumborum and psoas muscles, maintaining the natural reflection of the peritoneum. Visual assessment qualified whether any pin violated any retroperitoneal structure. Distance from the anterior border of the quadratus lumborum to the posterior-most reflection of the peritoneum was measured. For comparison, three additional torsos were positioned in lateral decubitus, and the above steps were repeated, only unilaterally (for a total of nine lateral decubitus approaches). Results In prone, no pin violated the peritoneum; three (3/18 total approaches) violated the kidney, all at L2-3 (3/6 approaches at L2-3). In lateral decubitus, all three L2-3 pins violated the kidney (3/3 approaches at L2-3); five of the six remaining pins from L3-5 violated the peritoneum (totaling eight violations in the nine total approaches). The incidence of any violation was significantly greater in lateral decubitus vs. prone (8/9 vs. 3/18, p=0.0006). The structure at risk (kidney vs. peritoneum) was significantly associated with disc level (p=0.0041): all kidney violations occurred at L2-3 and all peritoneal violations occurred at L3-4 or L4-5. Distance from the quadratus lumborum to the posterior-most reflection of the peritoneum averaged 8.7 cm (range: 6-10) in prone, and 2.9 cm (range: 2.5-3.2) in lateral decubitus (p=0.0129). Conclusion A cadaveric study of retroperitoneal anatomy demonstrates that there is an increased distance from the quadratus lumborum to the peritoneum in prone versus lateral decubitus and that the trajectory of approach to the lumbar discs risks violation of the peritoneum more frequently when accessing directly laterally versus posterolaterally. In either approach, care should be taken to identify and release the peritoneal reflection to create a safe passage to the lumbar discs.

Ernesto Bustamante Zuleta (1922-2021): pioneering teacher and practitioner of Colombian neurosurgery.

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.

A history of Colombian neurosurgery: events, persons, and outcomes that have shaped the specialty in the country.

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.

Anatomical study of the thoracolumbar radiculomedullary arteries, including the Adamkiewicz artery and supporting radiculomedullary arteries.

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.

The maxillary artery and its variants: an anatomical study with neurosurgical applications.

BACKGROUND: The maxillary artery (MA) has gained attention in neurosurgery particularly in cerebral revascularization techniques, intracranial endonasal approaches and endovascular procedures. OBJECTIVES: To describe and illustrate the anatomy of the MA and its neurosurgical importance in a detailed manner. METHODS: Six cadaveric heads (12 MAs) were injected with latex. The arteries and surrounding structures were dissected and studied using microsurgical techniques. The dimensions, course and branching patterns of the MA were recollected. In addition, 20 three-dimensional reconstruction CT head and neck angiograms (3D CTAs) of actual patients were correlated with the cadaveric findings. RESULTS: The MA can be divided in three segments: mandibular, pterygoid and pterygopalatine. Medial and lateral trunk variants regarding its course around the lateral pterygoid muscle can be found. The different branching patterns of the MA have a direct correlation with the course of its main trunk at the base of the skull. Branching and trunk variants on one side do not predict the findings on the contralateral side. CONCLUSION: In this study the highly variable course, branching patterns and relations of the MA are illustrated and described in human cadaveric heads and 3D CTAs. MA 3D CTA with bone reconstruction can be useful preoperatively for the identification of the medial or lateral course variants of this artery, particularly its pterygoid segment, which should be taken into account when considering the MA as a donor vessel for an EC-IC bypass.

Convexity meningiomas: study of recurrence factors with special emphasis on the cleavage plane in a series of 100 consecutive patients.

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.

Latex injection of cadaver heads: technical note.

BACKGROUND: Latex injection of cadaveric heads is an alternative to the standard technique of silicone injection. Thorough injections of the arterial and venous systems can be achieved by analyzing the anatomic and physiological variations of the vascular system of each specimen during the initial irrigation phase to tailor the subsequent latex injection. OBJECTIVE: To report on an improved method for color latex injection of cadaveric specimens using these techniques. METHODS: Thirty-two cadaver heads were injected and preserved for anatomic dissection. The critical steps included (1) cannulation of the cervical arteries and veins with Foley or Coude catheters, (2) "indirect" anatomic study of the vasculature during irrigation with water of the major arteries and veins, (3) fixation of the specimen with either formaldehyde or alcohol, and (4) color injection of the arteries and veins with red and blue latex, respectively. The injected specimens were dissected and assessed qualitatively for the extent and detail of arterial and venous filling. Assessment and recording of flow characteristics from the specimens during water irrigation of the arterial and venous systems dictated the order and technique for subsequent latex injections. RESULTS: Latex injections resulted in deeper penetration of colored solutions into small cerebral vessels and mesenchymal structures. Of 32 injected specimens, 25 (78%) had outstanding injections and 7 (21.8%) had suboptimal results. Latex solutions are simpler to use than silicone solutions. CONCLUSION: Latex injection of cadaveric heads based on indirect anatomic and physiological assessment of the vasculature of the specimen during the water irrigation phase results in outstanding specimens for microanatomical studies.

Deep brain stimulation of the orbitofrontal projections for the treatment of intermittent explosive disorder.

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.

Aneurysm of the petrous portion of the internal carotid artery at the foramen lacerum: anatomic, imaging, and otologic findings.

Aneurysms of the petrous portion of the internal carotid artery (ICA) are rare. Their etiology is usually congenital, traumatic, or mycotic. Depending on the size and location of the aneurysm, the direction of its growth, and the specific adjacent structures involved, patients may or may not present with signs and symptoms. When signs and symptoms do manifest, they may include headaches, epistaxis, a vascular retrotympanic mass with hemotympanum and/or otorrhagia, pulsatile tinnitus, hearing loss, vertigo, and Horner syndrome or Raeder paratrigeminal neuralgia. We describe the imaging aspects of the case of a 27-year-old man who presented with a 5-day history of unilateral symptoms secondary to a lesion located in the area of the right foramen lacerum. The lesion proved to be an aneurysm of the petrous portion of the ICA. We discuss the anatomic, imaging, and otologic aspects of ICA aneurysms in this location.

Percutaneous approach to the foramen ovale: an anatomical study of the extracranial trajectory with the incorrect trajectories to be avoided.

OBJECTIVE: Meckel's Cave may be accessed percutaneously through the foramen ovale (FO). Detailed knowledge of the region's anatomical surroundings is invaluable in improving target accuracy and preventing complications with this approach. The approach has been used in the treatment of trigeminal neuralgia as well as in performing biopsies of lesions located in the parasellar region, described formerly by the senior author (M.S.). A comprehensive cadaveric study of the region traversed by needle is thus presented. MATERIALS AND METHODS: Three cadaveric heads (six sides) were fixed in formaldehyde and injected with latex. A detailed description of the regional anatomical needle trajectories was performed. RESULTS: An "inverted pyramid" subdivided into three segments is described. The inferior third begins at cutaneous penetration and ends at the parotid duct (PD). The middle third extends from the PD to the lateral pterygoid muscle (LPM). The superior third starts from the LPM and ends at the FO. The main vascular anatomical variation was with regard to the maxillary artery (MA). In half of the cases, the MA traveled though the middle of the pyramid and in the other half through the upper third. CONCLUSIONS: Although widely used, the FO approach carries risks. Special attention is warranted when the needle traverses the upper third of the pyramid to avoid the variant course of the MA. Image-guided techniques and detailed anatomical knowledge are necessary to expand the use of this route not just for approach to lesions within the parasellar and upper third of the petroclival region but also to lesions invading the infratemporal fossa.

A successful combined endovascular and surgical treatment of a cranial base mucormycosis with an associated internal carotid artery pseudoaneurysm.

OBJECTIVE: We report a rare case of internal carotid artery pseudoaneurysm owing to rhinocerebral mucormycosis and review 40 reported cases from 1980 to present. CLINICAL PRESENTATION: A 38-year-old Caucasian man presented with a 3-day history of headache, diplopia, and numbness in the distribution of the left ophthalmic and maxillary branches of the trigeminal nerve. A complete left cavernous syndrome was discovered upon neurological examination. Magnetic resonance imaging scans revealed an inflammatory process involving the paranasal sinuses with extension into the left cavernous sinus, temporal fossa, and petrous bone. INTERVENTION: The patient was immediately treated with amphotericin B, atorvastatin, and daily hyperbaric oxygen sessions before surgical intervention. The patient underwent endovascular treatment of the associated mycotic pseudoaneurysm after carotid test occlusion in addition to a radical bilateral debridement of the paranasal sinuses and infratemporal and temporal fossa. CONCLUSION: Aggressive multimodal therapy is imperative for late-stage rhinocerebral mucormycosis. Extensive resection of infected tissue combined with amphotericin B, atorvastatin, and hyperbaric oxygen seems to be the best course of management. If the internal carotid artery is involved, endovascular intervention is clearly an option to attain this goal. Further research and longer follow-up periods are required to better understand the long-term implications of endovascular coiling and hyperbaric oxygen therapy for rhinocerebral mucormycosis.

Is exposure of the superior sagittal sinus necessary in the interhemispheric approach?

OBJECTIVE: Techniques for anterior interhemisperic craniotomy vary in respect to the degree of exposure of the superior sagittal sinus (SSS). The aim of this anatomic study is to quantify the increase in the angle of view gained by wide exposure and retraction of the SSS. METHODS: The anterior interhemispheric approach was performed in 10 cadaveric specimens with and without complete exposure and retraction of the SSS. Prespecified anatomic targets within the depth of the surgical field were used to calculate the angle of view. RESULTS: Complete exposure of the SSS in the anterior interhemispheric approach, increased the angle of view from 20.6 +/- 3 to 26.8 degrees, using the A4-A5 junction as a deep anatomic target (P = 0.008). When the free edge of the falx was considered as a deep anatomic target, complete exposure of the SSS increased the working angle from 34 +/- 3.14 to 42.1 +/- 4 (P = 0.0004). CONCLUSION: In this study, we demonstrate a significant increase in the angle of view after complete exposure of the SSS, targeting either deep (anterior cerebral artery) or more shallow structures (free falx edge).

Cerebral syphilitic gummata: a case presentation and analysis of 156 reported cases.

OBJECTIVE: Cerebral syphilitic gummata are rare manifestations of tertiary, meningovascular syphilis. No extensive characterization of these lesions has been published recently, and only a few small reviews containing imaging findings have been published to date. To better characterize cerebral gummata, we present a case seen at Tulane University, followed by an extensive review of the literature. CLINICAL PRESENTATION: A 56-year-old man with a history of treated syphilis presented with seizures and confusion. A rapid plasma reagin titer was reactive in serum but Venereal Disease Research Laboratory results were negative in cerebrospinal fluid. Neuroimaging demonstrated an occipital lesion and the patient underwent subtotal resection. The pathological examination demonstrated a syphilitic gumma containing Treponema pallidum visualized by fluorescence immunostaining. METHODS: An extensive literature search was performed for published case reports of cerebral gummata. RESULTS: One hundred fifty-six cases containing 185 lesions were located. Patients presented with signs and symptoms based on location. Lesions are more common in men (64%) and those aged 18 to 39 years. Cerebrospinal fluid syphilis tests were positive in 64%. Lesions are located everywhere but are most common on the convexities (66%). Computed tomography usually reveals a hypodense lesion that enhances. Magnetic resonance imaging usually demonstrates hypointensity on T1, hyperintensity on T2, and enhancement with gadolinium. Most patients are responsive to antiluetic therapy, with the majority demonstrating complete or near-complete imaging and symptom resolution. CONCLUSION: Cerebral gummata are rare lesions. Intravenous penicillin G with imaging follow-up is recommended for most patients. Surgery should be reserved for those unresponsive to antibiotics or those with acutely elevated intracranial pressure.

Normal head impulse test differentiates acute cerebellar strokes from vestibular neuritis.

OBJECTIVE: To test the diagnostic accuracy of the horizontal head impulse test (h-HIT) of vestibulo-ocular reflex (VOR) function in distinguishing acute peripheral vestibulopathy (APV) from stroke. Most patients with acute vertigo, nausea/vomiting, and unsteady gait have benign APV (vestibular neuritis or labyrinthitis) as a cause. However, some harbor life-threatening brainstem or cerebellar strokes that mimic APV. A positive h-HIT (abnormal VOR) is said to predict APV. METHODS: Cross-sectional study at an urban, academic hospital over 6 years. Consecutive acute vestibular syndrome patients at high risk for stroke underwent structured examination (including h-HIT), neuroimaging, and admission. Stroke was confirmed by neuroimaging (MRI or CT). APV was diagnosed by normal MRI and appropriate clinical evolution in follow-up. RESULTS: Forty-three subjects enrolled. One had an equivocal h-HIT. Patients with APV had a positive h-HIT (n = 8/8, 100%). Most patients with stroke had a negative h-HIT (n = 31/34, 91%). However, contrary to conventional wisdom, three patients with stroke (9%) demonstrated a positive h-HIT (1 vestibulocerebellar, 1 pontocerebellar, 1 pontocerebello-labyrinthine stroke). CONCLUSIONS: Patients with lateral pontine and cerebellar strokes can have a positive horizontal head impulse test (h-HIT), so the sign's presence cannot be solely relied upon to identify a benign pathology. Additional clinical features (e.g., directionality of nystagmus, severity of truncal instability, nature of hearing loss) must be considered in patients with acute vestibular syndrome with a positive h-HIT before a central localization can be confidently excluded. Nonetheless, the h-HIT remains a useful bedside test-in acute vestibular syndrome patients, a negative h-HIT (i.e., normal VOR) strongly suggests a central lesion with a pseudo-labyrinthine presentation.