Chen Jingrun (1933–1996), perhaps the most prodigious mathematician of his time, focused on the field of analytical number theory. His work on Waring's problem, Legendre's conjecture, and Goldbach's conjecture led to progress in analytical number theory in the form of “Chen's Theorem,” which he published in 1966 and 1973. His early life was ravaged by the Second Sino-Japanese War and the Chinese Cultural Revolution. On the verge of solving Goldbach's conjecture in 1984, Chen was struck by a bicyclist while also bicycling and suffered severe brain trauma. During his hospitalization, he was also found to have Parkinson's disease. Chen suffered another serious brain concussion after a fall only a few months after recovering from the bicycle crash. With significant deficits, he remained hospitalized for several years without making progress while receiving modern Western medical therapies. In 1988 traditional Chinese medicine experts were called in to assist with his treatment. After a year of acupuncture and oxygen therapy, Chen could control his basic bowel and bladder functions, he could walk slowly, and his swallowing and speech improved. When Chen was unable to produce complex work or finish his final work on Goldbach's conjecture, his mathematical pursuits were taken up vigorously by his dedicated students. He was able to publish Youth Math, a mathematics book that became an inspiration in Chinese education. Although he died in 1996 at the age of 63 after surviving brutal political repression, being deprived of neurological function at the very peak of his genius, and having to be supported by his wife, Chen ironically became a symbol of dedication, perseverance, and motivation to his students and associates, to Chinese youth, to a nation, and to mathematicians and scientists worldwide.
Ting Lei, Evgenii Belykh, Alexander B. Dru, Kaan Yagmurlu, Ali M. Elhadi, Peter Nakaji and Mark C. Preul
Shu-Guang Gao, Guang-Hua Lei, Hong-Bo He, Hua Liu, Wen-Feng Xiao, Ting Wen, Jie-Yu Liang and Kang-Hua Li
With the increasing advocacy for total disc replacement (TDR) as a potential alternative to fusion in the management of lumbar degenerative disc disease, intradiscal pressures (IDPs) and facet joint stresses at the adjacent levels of spine have generated considerable interest. The purpose of this study was to compare adjacent-level IDPs and facet joint stresses among TDR, discectomy, and fusion.
Ten fresh human cadaveric lumbar specimens (L2–S1) were subjected to an unconstrained load in axial torsion, lateral bending, flexion, and extension by using multidirectional flexibility test. Four surgical treatment modes—control (disc intact), discectomy, TDR, and fusion—were tested in sequential order at L4–5. During testing, the IDPs and facet forces following each treatment were calculated at the adjacent vertebral levels (L3–4 and L5–S1).
Intradiscal pressures and facet force pressures were similar between the intact condition and the TDR reconstruction at the L3–4 and L5–S1 levels under all loading conditions (p > 0.05). Compared with the intact and TDR groups, the discectomy and fusion groups had higher IDPs at the L3–4 and L5–S1 levels under all loading conditions (p < 0.05). No significant difference in the facet force pressure was noted among the intact, discectomy, and TDR groups at the L3–4 and L5–S1 levels under any loading conditions (p > 0.05). However, the facet force pressure produced for fusion was significantly higher than the mean values obtained for the intact, discectomy, and TDR groups at the L3–4 and L5–S1 levels under all loading conditions (p < 0.05).
Lumbar TDR maintained adjacent-level IDPs and facet force pressures near the values for intact spines, whereas adjacent-level IDPs tended to increase after discectomy or fusion and facet forces tended to increase after fusion.
Evgenii Belykh, Kashif Malik, Isabelle Simoneau, Kaan Yagmurlu, Ting Lei, Daniel D. Cavalcanti, Vadim A. Byvaltsev, Nicholas Theodore and Mark C. Preul
André Feil (1884–1955) was a French physician best recognized for his description, coauthored with Maurice Klippel, of patients with congenital fusion of cervical vertebrae, a condition currently known as Klippel-Feil syndrome. However, little is known about his background aside from the fact that he was a student of Klippel and a physician who took a keen interest in describing congenital anomalies. Despite the relative lack of information on Feil, his contributions to the fields of spinal disease and teratology extended far beyond science to play an integral role in changing the misguided perception shrouding patients with disfigurements, defects, deformities, and so-called monstrous births. In particular, Feil's 1919 medical school thesis on cervical abnormalities was a critical publication in defying long-held theory and opinion that human “monstrosities,” anomalies, developmental abnormalities, and altered congenital physicality were a consequence of sinful behavior or a reversion to a primitive state. Indeed, his thesis on a spinal deformity centering on his patient, L. Joseph, was at the vanguard for a new view of a patient as nothing less than fully human, no matter his or her physicality or appearance.
M. Yashar S. Kalani, Ting Lei, Nikolay L. Martirosyan, Mark E. Oppenlander, Robert F. Spetzler and Peter Nakaji
The mesial temporal lobe can be approached via a pterional or orbitozygomatic craniotomy, the subtemporal approach, or transcortically. Alternatively, the entire mesial temporal lobe can be accessed using a lateral supracerebellar transtentorial (SCTT) approach. Here we describe the technical nuances of patient positioning, craniotomy, supracerebellar dissection, and tentorial disconnection to traverse the tentorial incisura to arrive at the posterior mesial temporal lobe for a cavernous malformation. The SCTT approach is especially useful for lesions in the dominant temporal lobe where an anterolateral approach may endanger language centers or the vein of Labbé.
The video can be found here: https://youtu.be/D8mIR5yeiVw.
Feng Wan, Ling Li, Jingcao Chen, Jian Chen, Ting Lei, Delin Xue, Hongquan Niu, Kai Shu, Ping Zhang, Zhengming Yang and Yuping Wang
The authors performed a study to investigate the clinical manifestations, treatment strategies, and possible pathogenesis of conus medullaris schistosomiasis.
Six cases collected from the authors’ experience and four cases reported in the literature were studied retrospectively for clinical manifestations, treatment outcomes, and prognosis. All patients experienced progressive lower-extremity weakness and functional bowel and bladder impairment. Although the magnetic resonance (MR) imaging results suggested the presence of a conus medullaris tumor, schistosomiasis was diagnosed based on pathological results obtained in the 10 patients. The results of surgery followed by pyquiton and hormone treatment confirmed the diagnosis, and the patients’ prognoses were good.
This pathological entity is predominantly found in adults, and the clinical manifestations have no specificity, although the MR imaging may provide some clues. As a form of ectopic schistosomiasis, conus medullaris schistosomiasis deserves special consideration and further exploration. If an early diagnosis can be made and pyquiton and hormone therapy is given, surgery can be avoided and the prognosis will remain good.
Evgenii Belykh, Kaan Yağmurlu, Ting Lei, Sam Safavi-Abbasi, Mark E. Oppenlander, Nikolay L. Martirosyan, Vadim A. Byvaltsev, Robert F. Spetzler, Peter Nakaji and Mark C. Preul
The best approach to deep-seated lateral and third ventricle lesions is a function of lesion characteristics, location, and relationship to the ventricles. The authors sought to examine and compare angles of attack and surgical freedom of anterior ipsilateral and contralateral interhemispheric transcallosal approaches to the frontal horn of the lateral ventricle using human cadaveric head dissections. Illustrative clinical experiences with a contralateral interhemispheric transcallosal approach and an anterior interhemispheric transcallosal transchoroidal approach are also related.
Five formalin-fixed human cadaveric heads (10 sides) were examined microsurgically. CT and MRI scans obtained before dissection were uploaded and fused into the navigation system. The authors performed contralateral and ipsilateral transcallosal approaches to the lateral ventricle. Using the navigation system, they measured areas of exposure, surgical freedom, angles of attack, and angle of view to the surgical surface. Two clinical cases are described.
The exposed areas of the ipsilateral (mean [± SD] 313.8 ± 85.0 mm2) and contralateral (344 ± 87.73 mm2) interhemispheric approaches were not significantly different (p = 0.12). Surgical freedom and vertical angles of attack were significantly larger for the contralateral approach to the most midsuperior reachable point (p = 0.02 and p = 0.01, respectively) and to the posterosuperior (p = 0.02 and p = 0.04) and central (p = 0.04 and p = 0.02) regions of the lateral wall of the lateral ventricle. Surgical freedom and vertical angles of attack to central and anterior points on the floor of the lateral ventricle did not differ significantly with approach. The angle to the surface of the caudate head region was less steep for the contralateral (135.6° ± 15.6°) than for the ipsilateral (152.0° ± 13.6°) approach (p = 0.02).
The anterior contralateral interhemispheric transcallosal approach provided a more expansive exposure to the lower two-thirds of the lateral ventricle and striothalamocapsular region. In normal-sized ventricles, the foramen of Monro and the choroidal fissure were better visualized through the lateral ventricle ipsilateral to the craniotomy than through the contralateral approach.
Evgenii Belykh, Ting Lei, Sam Safavi-Abbasi, Kaan Yagmurlu, Rami O. Almefty, Hai Sun, Kaith K. Almefty, Olga Belykh, Vadim A. Byvaltsev, Robert F. Spetzler, Peter Nakaji and Mark C. Preul
Microvascular anastomosis is a basic neurosurgical technique that should be mastered in the laboratory. Human and bovine placentas have been proposed as convenient surgical practice models; however, the histologic characteristics of these tissues have not been compared with human cerebral vessels, and the models have not been validated as simulation training models. In this study, the authors assessed the construct, face, and content validities of microvascular bypass simulation models that used human and bovine placental vessels.
The characteristics of vessel segments from 30 human and 10 bovine placentas were assessed anatomically and histologically. Microvascular bypasses were performed on the placenta models according to a delineated training module by “trained” participants (10 practicing neurosurgeons and 7 residents with microsurgical experience) and “untrained” participants (10 medical students and 3 residents without experience). Anastomosis performance and impressions of the model were assessed using the Northwestern Objective Microanastomosis Assessment Tool (NOMAT) scale and a posttraining survey.
Human placental arteries were found to approximate the M2–M4 cerebral and superficial temporal arteries, and bovine placental veins were found to approximate the internal carotid and radial arteries. The mean NOMAT performance score was 37.2 ± 7.0 in the untrained group versus 62.7 ± 6.1 in the trained group (p < 0.01; construct validity). A 50% probability of allocation to either group corresponded to 50 NOMAT points. In the posttraining survey, 16 of 17 of the trained participants (94%) scored the model's replication of real bypass surgery as high, and 16 of 17 (94%) scored the difficulty as “the same” (face validity). All participants, 30 of 30 (100%), answered positively to questions regarding the ability of the model to improve microsurgical technique (content validity).
Human placental arteries and bovine placental veins are convenient, anatomically relevant, and beneficial models for microneurosurgical training. Microanastomosis simulation using these models has high face, content, and construct validities. A NOMAT score of more than 50 indicated successful performance of the microanastomosis tasks.