Neurosurgical Randomized Trials in Low- and Middle-Income Countries.
Essential surgery as a key component of primary health care: reflections on the 40th anniversary of Alma-Ata.
BMJ global health
2018; 3 (Suppl 3): e000705
Traumatic brain injury: a global challenge
2017; 16 (12): 949?50
The anterior temporal artery: an underutilized but robust donor for revascularization of the distal middle cerebral artery
JOURNAL OF NEUROSURGERY
2017; 127 (4): 740?47
BACKGROUND: The setting of a randomized trial can determine whether its findings are generalizable and can therefore apply to different settings. The contribution of low- and middle-income countries (LMICs) to neurosurgical randomized trials has not been systematically described before.OBJECTIVE: To perform a systematic analysis of design characteristics and methodology, funding source, and interventions studied between trials led by and/or conducted in high-income countries (HICs) vs LMICs.METHODS: From January 2003 to July 2016, English-language trials with >5 patients assessing any one neurosurgical procedure against another procedure, nonsurgical treatment, or no treatment were retrieved from MEDLINE, Scopus, and Cochrane Library. Income classification for each country was assessed using the World Bank Atlas method.RESULTS: A total of 73.3% of the 397 studies that met inclusion criteria were led by HICs, whereas 26.7% were led by LMICs. Of the 106 LMIC-led studies, 71 were led by China. If China is excluded, only 8.8% were led by LMICs. HIC-led trials enrolled a median of 92 patients vs a median of 65 patients in LMIC-led trials. HIC-led trials enrolled from 7.6 sites vs 1.8 sites in LMIC-led studies. Over half of LMIC-led trials were institutionally funded (54.7%). The majority of both HIC- and LMIC-led trials evaluated spinal neurosurgery, 68% and 71.7%, respectively.CONCLUSION: We have established that there is a substantial disparity between HICs and LMICs in the number of published neurosurgical trials. A concerted effort to invest in research capacity building in LMICs is an essential step towards ensuring context- and resource-specific high-quality evidence is generated.
View details for DOI 10.1093/neuros/nyaa049
View details for PubMedID 32171011
Assessment of the Temporopolar Artery as a Donor Artery for Intracranial-Intracranial Bypass to the Middle Cerebral Artery: Anatomic Feasibility Study
2017; 104: 171?79
OBJECTIVE The anterior temporal artery (ATA) supplies an area of the brain that, if sacrificed, does not cause a noticeable loss of function. Therefore, the ATA may be used as a donor in intracranial-intracranial (IC-IC) bypass procedures. The capacities of the ATA as a donor have not been studied previously. In this study, the authors assessed the feasibility of using the ATA as a donor for revascularization of different segments of the distal middle cerebral artery (MCA). METHODS The ATA was studied in 15 cadaveric specimens (8 heads, excluding 1 side). First, the cisternal segment of the artery was untethered from arachnoid adhesions and small branches feeding the anterior temporal lobe and insular cortex, to evaluate its capacity for a side-to-side bypass to insular, opercular, and cortical segments of the MCA. Any branch entering the anterior perforated substance was preserved. Then, the ATA was cut at the opercular-cortical junction and the capacity for an end-to-side bypass was assessed. RESULTS From a total of 17 ATAs, 4 (23.5%) arose as an early MCA branch. The anterior insular zone and the frontal parasylvian cortical arteries were the best targets (in terms of mobility and caliber match) for a side-to-side bypass. Most of the insula was accessible for end-to-side bypass, but anterior zones of the insula were more accessible than posterior zones. End-to-side bypass was feasible for most recipient cortical arteries along the opercula, except for posterior temporal and parietal regions. Early ATAs reached significantly farther on the insular MCA recipients than non-early ATAs for both side-to-side and end-to-side bypasses. CONCLUSIONS The ATA is a robust arterial donor for IC-IC bypass procedures, including side-to-side and end-to-side techniques. The evidence provided in this work supports the use of the ATA as a donor for distal MCA revascularization in well-selected patients.
View details for DOI 10.3171/2016.8.JNS161225
View details for Web of Science ID 000411661400005
View details for PubMedID 27834592
"To Operate" Versus "Not to Operate" in Low-Resource Settings: Example of Aneurysm Surgery in Rural Iran and Impact of Mastery of Neurosurgical Anatomy
2017; 100: 628?31
Intracranial-intracranial bypass is a valuable cerebral revascularization option. Despite several advantages, one of the main shortcomings of the intracranial-intracranial bypass is the possibility of ischemic complications of the donor artery. However, when sacrificed, the temporopolar artery (TPA) is not associated with major neurologic deficits. We sought to define the role of TPA as a donor for revascularization of the middle cerebral artery (MCA).Pterional craniotomy was performed on 14 specimens. The TPA was released from arachnoid trabecula, and the small twigs to the temporal lobe were cut. The feasibility of side-to-side and end-to-side bypass to the farthest arterial targets on insular, opercular, and cortical MCA branches was assessed. The distance of the bypass point was measured in reference to limen insulae.A total of 15 TPAs were assessed (1 specimen had 2 TPAs). The average cisternal length of the TPA was 37.3 mm. For side-to-side bypass, the TPA was a poor candidate as an intracranial donor, except for the cortical orbitofrontal artery, which was reached in 87% of cases. However, the end-to-side bypass was successfully completed for most arteries (87%-100%) on the anterior frontal operculum and more than 50% of the cortical or opercular middle and posterior temporal arteries. There was no correlation between the TPA's cisternal length and maximum bypass reach.When of favorable diameter, the TPA is a competent donor for intracranial-intracranial bypass to MCA branches at the anterior insula, and anterior frontal and middle temporal opercula (arteries anterior to the precentral gyrus coronal plane).
View details for DOI 10.1016/j.wneu.2017.04.142
View details for Web of Science ID 000407713100026
View details for PubMedID 28465270
Anterior Temporal Artery-to-Anterior Cerebral Artery Bypass: Anatomic Feasibility of a Novel Intracranial-Intracranial Revascularization Technique
2017; 99: 667?73
Subarachnoid hemorrhage (SAH) has a global incidence of 9/100,000. In low-resource settings, where neurosurgical capacity is diminished through fewer human and technological resources, neurosurgeons may not be prepared to operate on aneurysm cases in emergent situations. We report a patient presented with aneurysmal SAH in rural Iran, creating the dilemma of the will for the neurosurgeon. We discuss the impact of the knowledge of neurosurgical anatomy on the resolution of this dilemma.A 30-year-old female presented with aneurysmal SAH to a remote medical facility in rural Iran. A safe and fast referral to a nearby vascular neurosurgery center was not available. A contrasted computed tomography (the only available imaging modality) revealed a carotid bifurcation aneurysm. The situation was explained to the patient and family, and they decided to proceed with surgery. With the minimum technical radiological and surgical equipment available, the surgeon managed to successfully treat the patient, aided by his mastery of the neurosurgical anatomy. The patient was discharged without any complication.We highlight the importance of mastery of neurosurgical anatomy, which was critical in achieving a favorable patient outcome. The necessity of developing low-cost platforms to enhance neurosurgical anatomy learning in neurosurgical residency programs of low-resource regions and countries is discussed.
View details for DOI 10.1016/j.wneu.2017.01.111
View details for Web of Science ID 000401930000082
View details for PubMedID 28179175
Topographic Surgical Anatomy of the Parasylvian Anterior Temporal Artery for Intracranial-Intracranial Bypass
2016; 93: 67?72
Complex aneurysms of the anterior cerebral artery (ACA) may require a bypass procedure as part of their surgical management. Most current bypass paradigms recommend technically demanding side-to-side anastomosis of pericallosal arteries or use of interposition grafts, which involve longer ischemia times. The purpose of this study is to assess the feasibility of an anterior temporal artery (ATA) to ACA end-to-side bypass.Fourteen cadaveric specimens (17 ATAs) were prepared for surgical simulation. The cisternal course of the ATA was freed from perforating branches and arachnoid. The M3-M4 junction of the ATA was cut, and the artery was mobilized to the interhemispheric fissure. The feasibility of ATA bypass to the precommunicating and postcommunicating ACA was assessed in relation to the cisternal length and branching pattern of the middle cerebral artery.Successful anastomosis was feasible in 14 ATAs (82%). Three ATAs did not reach the ACA. These ATAs were branching distally and originated from the M3 (opercular) middle cerebral artery. In specimens where bypass was not feasible, the average cisternal length of the ATA was significantly shorter than the rest.ATA-ACA bypass is anatomically feasible and may be a useful alternative to other revascularization techniques in selected patients. It is technically simpler than A3-A3 in situ bypass. ATA-ACA bypass can be performed through the same pterional exposure used for the ACA aneurysms, sparing the patient an additional interhemispheric approach, required for the A3-A3 anastomosis.
View details for DOI 10.1016/j.wneu.2016.12.007
View details for Web of Science ID 000397190100092
View details for PubMedID 27965074
Meeting the Unmet Need: Training General Surgeons to Perform Life-Saving Neurosurgical Procedures in Low-Resource Settings
2016; 93: 474
Revascularization of the upper posterior circulation with the anterior temporal artery: an anatomical feasibility study
JOURNAL OF NEUROSURGERY
2018; 129 (1): 121?27
The anterior temporal artery (ATA) is an appealing donor artery for intracranial-intracranial bypass procedures. However, its identification may be difficult. Current literature lacks useful landmarks to help identify the ATA at the surface of the sylvian fissure. The objective of this study was to define the topographic anatomy of the cortical segment of the ATA relative to constant landmarks exposed during the pterional approach.The temporopolar artery (TPA), ATA, and middle temporal artery (MTA) were examined in 16 cadaveric specimens. The topographic anatomy and key landmarks of the arteries at the sylvian fissure were recorded. The distance between the point of emergence from the sylvian fissure to the lesser sphenoid wing and anterior tip of the temporal lobe was measured. The features of the inferior frontal gyrus relative to each of the arteries at the sylvian fissure were also recorded.The average distances from the lesser sphenoid wing to the TPA, ATA, and MTA were 3.7 mm, 21.2 mm, and 37 mm. The mean distances from the temporal pole were TPA, 14.7 mm; ATA, 32.0 mm; and MTA, 45.4 mm. The differences between the average distances were statistically significant (P < 0.0001). The ATA most frequently faced pars triangularis, whereas the TPA always faced pars orbitalis. The MTA was always found posterior to the junction of pars triangularis and pars opercularis.This article provides topographic evidence for efficient identification of the ATA in the parasylvian space. The key relationship and landmarks identified in this study may increase efficiency and safety when harvesting the ATA for intracranial-intracranial bypass.
View details for DOI 10.1016/j.wneu.2016.05.050
View details for Web of Science ID 000390352000012
View details for PubMedID 27241097
Cross-Wise Counter Clipping of a Dolichoectatic Left Vertebral Artery Aneurysm: 3-Dimensional Operative Video
2018; 14 (2): 204
Tentative Stacking Technique with Tandem Clipping and Bypass for an MCA Aneurysm: 3-Dimensional Operative Video
2018; 14 (2): 202
Anatomical Assessment of the Temporopolar Artery for Revascularization of Deep Recipients.
Operative neurosurgery (Hagerstown, Md.)
OBJECTIVE In various disease processes, including unclippable aneurysms, a bypass to the upper posterior circulation (UPC) including the superior cerebellar artery (SCA) and posterior cerebral artery (PCA) may be needed. Various revascularization options exist, but the role of intracranial (IC) donors has not been scrutinized. The objective of this study was to evaluate the anatomical feasibility of utilizing the anterior temporal artery (ATA) for revascularization of the UPC. METHODS ATA-SCA and ATA-PCA bypasses were performed on 14 cadaver specimens. After performing an orbitozygomatic craniotomy and opening the basal cisterns, the ATA was divided at the M3-M4 junction and mobilized to the crural cistern to complete an end-to-side bypass to the SCA and PCA. The length of the recipient artery between the anastomosis and origin was measured. RESULTS Seventeen ATAs were found. Successful anastomosis was performed in 14 (82%) of the ATAs. The anastomosis point on the PCA was 14.2 mm from its origin on the basilar artery. The SCA anastomosis point was 10.1 mm from its origin. Three ATAs did not reach the UPC region due to a common opercular origin with the middle temporal artery. The ATA-SCA bypass was also applied to the management of an incompletely coiled SCA aneurysm. CONCLUSIONS The ATA is a promising IC donor for UPC revascularization. The ATA is exposed en route to the proximal SCA and PCA through the pterional-orbitozygomatic approach. Also, the end-to-side anastomosis provides an efficient and straightforward bypass without the need to harvest a graft or perform multiple or difficult anastomoses.
View details for DOI 10.3171/2017.3.JNS162865
View details for Web of Science ID 000440655000015
View details for PubMedID 28937325
Supracerebellar-Infratentorial Approach for Resection of Tectal and Thalamic Cavernous Malformations: 3-Dimensional Operative Video.
Operative neurosurgery (Hagerstown, Md.)
2018; 14 (3): 316
Macrovascular Decompression of Brainstem and Lower Cranial Nerves: 3-Dimensional Operative Video
2018; 14 (1): 81
Intracranial-Intracranial A1 ACA-SVG-M2 MCA+M2 MCA Double Reimplantation Bypass For a Giant Middle Cerebral Artery Aneurysm: 3-Dimensional Operative Video
2018; 14 (1): 84
Contralateral Anterior Interhemispheric Approach to Medial Frontal Arteriovenous Malformation: 3-Dimensional Operative Video
2018; 14 (1): 86
Simultaneous Clipping of a Basilar Apex Aneurysm and Right Middle Cerebral Artery Aneurysm: 3-Dimensional Operative Video.
Operative neurosurgery (Hagerstown, Md.)
2018; 15 (1): 97
Clip Reconstruction of Large Posterior Inferior Cerebellar Artery Aneurysm: 3-Dimensional Operative Video.
Operative neurosurgery (Hagerstown, Md.)
2018; 14 (5): 590
Hearing Preservation During Anterior Petrosectomy: The "Cochlear Safety Line"
2017; 99: 618?22
Intracranial-intracranial and extracranial-intracranial bypass options for revascularization of deep cerebral recipients are limited and technically demanding.To assess the anatomical feasibility of using the temporopolar artery (TPA) for revascularization of the anterior cerebral artery (ACA), posterior cerebral artery (PCA), and superior cerebellar arteries (SCA).Orbitozygomatic craniotomy was performed bilaterally on 8 cadaveric heads. The cisternal segment of the TPA was dissected. The TPA was cut at M3-M4 junction with its proximal and distal calibers and the length of the cisternal segment measured. Feasibility of the TPA-A1-ACA, TPA-A2-ACA, TPA-SCA, and TPA-PCA bypasses were assessed.A total of 17 TPAs were identified in 16 specimens. The average distal TPA caliber was 1.0 ± 0.2 mm, and the average cisternal length was 37.5 ± 9.4 mm. TPA caliber was ? 1.0 mm in 12 specimens (70%). The TPA-A1-ACA bypass was feasible in all specimens, whereas the TPA reached the A2-ACA, SCA, and PCA in 94% of specimens (16/17). At the point of anastomosis, the average recipient caliber was 2.5 ± 0.5 mm for A1-ACA, and 2.3 ± 0.7 mm for A2-ACA. The calibers of the SCA and PCA at the anastomosis points were 2.0 ± 0.6 mm, and 2.7 ± 0.8 mm, respectively.The TPA-ACA, TPA-PCA, and TPA-SCA bypasses are anatomically feasible and may be used when the distal caliber of the TPA stump is optimal to provide adequate blood flow. This study lays foundations for clinical use of the TPA for ACA revascularization in well-selected cases.
View details for DOI 10.1093/ons/opy115
View details for PubMedID 29850897
Combined Endoscopic Transoral and Endonasal Approach to the Jugular Foramen: A Multiportal Expanded Access to the Clivus
2016; 95: 62?70
Identification and protection of the cochlea during anterior petrosectomy is key to prevent hearing loss. Currently, there is no optimal method to infer the position of the cochlea in relation to the Kawase quadrangle; therefore, damage to the cochlea during anterior petrosectomy remains a substantial risk.To identify and define landmarks available during anterior petrosectomy to locate the cochlea and prevent its damage.The Kawase approach was simulated in 11 cadaveric specimens. After a subtemporal craniotomy, foramen spinosum and ovale were identified. Anterior petrosectomy was performed, and the upper dural transitional fold (UDTF) was identified. Two virtual lines, from foramen spinosum (line A), and the lateral rim of the foramen ovale (line B), were projected to intersect the UDTF perpendicularly. The cochlea was exposed, and the distances between lines A and B and the closest point of the outer rim and membranous part of the cochlea were measured.The average distance between line A to the bony and membranous edges of the anteromedial cochlea was -0.62 ± 1.38 mm and 0.38 ± 1.63 mm, respectively. The average distance between line B to the bony and membranous edges of the cochlea was 1.82 ± 0.99 mm and 2.78 ± 1.29 mm, respectively. Line B (cochlear safety line) never intersected the cochlea.The cochlear safety line is a reliable landmark to avoid the cochlea during the Kawase approach. When expanding the anterior petrosectomy posteriorly, the cochlear safety line can be used as a reliable landmark to prevent exposure of the cochlea, thus preventing hearing loss.
View details for DOI 10.1016/j.wneu.2016.11.019
View details for Web of Science ID 000397190100085
View details for PubMedID 27913265
Three-Dimensional Imaging in Neurosurgical Research and Education
2016; 91: 317?25
The expanded endoscopic endonasal ("far medial") approach to the inferior clivus provides a unique surgical corridor to the ventral surface of the pontomedullary and cervicomedullary junctions. However, exposing neoplasms involving the jugular foramen (JF) through this approach requires extensive nasopharyngeal resection and lateral dissection beyond the boundaries of the endonasal corridor, limiting the extent of resection and restricting to use of this approach to expert surgeons. Here we describe a multiportal endoscopic transoral and endonasal approach to maximize surgical access to the JF and clivus.A multiportal endoscopic transoral and endoscopic approach to the JF and lower clivus was simulated in 8 specimens. A transoral corridor was created through a soft palate incision. The JF and parapharyngeal space were dissected through the transoral trajectory under endoscopic endonasal view. The length of the corridor of the transnasal and transoral trajectories was measured.The JF was exposed intracranially and extracranially. The exposure extended superiorly to the sphenoid floor, inferiorly to the anterior atlanto-occipital space, and laterally to the internal acoustic meatus and parapharyngeal space. The cisternal parts of the cranial nerves VII-XII and C1 nerve bundles were accessible. Exposure of the JF contents and parapharyngeal space was possible using straight scopes, without Eustachian tube resection. The working corridor to the JF was significantly shorter through the mouth than through the nose (P < 0.0001).This approach provides access to the JF from a ventromedial trajectory, enabling panoramic views, and outlines an expanded surgical exposure (superolateral intradural and inferolateral extracranial). It may provide optimal access for resection of dumbbell-shaped lesions of the JF.
View details for DOI 10.1016/j.wneu.2016.07.073
View details for Web of Science ID 000390354800010
View details for PubMedID 27481601
We describe the setup and use of different 3-dimensional (3-D) recording modalities (macroscopic, endoscopic, and microsurgical) in our laboratory and operating room and discuss their implications in neurosurgical research and didactics. We also highlight the utility of 3-D images in providing depth perception and discernment of structures compared with 2-dimensional (2-D) images.The technical details for equipment and laboratory setup for obtaining 3-D images were described. The stereoscopic pair of images was obtained using a modified "shoot-shift-shoot" method and later converged to a 3-D image. For microsurgical procedures, 3-D images were obtained using an integrated 3-D video camera coupled to the surgical microscope in both the laboratory and the operating room. Illustrative cases were used to compare 2-D and 3-D images.Side-by-side comparisons of 2-D and 3-D images obtained using all modalities revealed that 3-D imaging was superior to 2-D imaging in providing depth perception and structure identification.This is the first report in the literature of the methodology for obtaining 3-D endoscopic endonasal images using the 2-D endoscope. The use of 3-D imaging is invaluable in neurosurgical research and education, as it provides immediate depth perception (third dimension), allowing efficient understanding of key spatial relationships. Integration of 3-D imaging in neurosurgical residency programs may increase learning efficiency and shorten learning curves. However, use of 3-D imaging should not replace direct hands-on practice.
View details for DOI 10.1016/j.wneu.2016.04.023
View details for Web of Science ID 000380365000046
View details for PubMedID 27102636