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Yue-Qi Du, Teng Li, Chao Ma, Guang-Yu Qiao, Yi-Heng Yin and Xin-Guang Yu

OBJECTIVE

The authors conducted a study to investigate the biomechanical feasibility and stability of C1 lateral mass–C2 bicortical translaminar screw (C1LM-C2TL) fixation, C1 lateral mass–C2/3 transarticular screw (C1LM-C2/3TA) fixation, and C1LM-C2/3TA fixation with transverse cross-links (C1LM-C2/3TACL) as alternative techniques to the Goel-Harms technique (C1 lateral mass–C2 pedicle screw [C1LM-C2PS] fixation) for atlantoaxial fixation.

METHODS

Eight human cadaveric cervical spines (occiput–C7) were tested using an industrial robot. Pure moments that were a maximum of 1.5 Nm were applied in flexion-extension (FE), lateral bending (LB), and axial rotation (AR). The specimens were first tested in the intact state and followed by destabilization (a type II odontoid fracture) and fixation as follows: C1LM-C2PS, C1LM-C2TL, C1LM-C2/3TA, and C1LM-C2/3TACL. For each condition, the authors evaluated the range of motion and neutral zone across C1 and C2 in all directions.

RESULTS

Compared with the intact spine, each instrumented spine significantly increased in stability at the C1–2 segment. C1LM-C2TL fixation demonstrated similar stability in FE and LB and greater stability in AR than C1LM-C2PS fixation. C1LM-C2/3TA fixation was equivalent in LB and superior in FE to those of C1LM-C2PS and C1LM-C2TL fixation. During AR, the C1LM-C2/3TA–instrumented spine failed to maintain segmental stability. After adding a cross-link, the rotational stability was significantly increased in the C1LM-C2/3TACL–instrumented spine compared with the C1LM-C2/3TA–instrumented spine. Although inferior to C1LM-C2TL fixation, the C1LM-C2/3TACL–instrumented spine showed equivalent rotational stability to the C1LM-C2PS–instrumented spine.

CONCLUSIONS

On the basis of our biomechanical study, C1LM-C2TL and C1LM-C2/3TACL fixation resulted in satisfactory atlantoaxial stabilization compared with C1LM-C2PS. Therefore, the authors believe that the C1LM-C2TL and C1LM-C2/3TACL fixation may serve as alternative procedures when the Goel-Harms technique (C1LM-C2PS) is not feasible due to anatomical constraints.

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Christopher D. Witiw, Fabrice Smieliauskas, Sandra A. Ham and Vincent C. Traynelis

OBJECTIVE

Cervical disc replacement (CDR) has emerged as an alternative to anterior cervical discectomy and fusion (ACDF) for the management of cervical spondylotic pathology. While much is known about the efficacy of CDR within the constraints of a well-controlled, experimental setting, little is known about general utilization. The authors present an analysis of temporal and geographic trends in “real-world” utilization of CDR among those enrolled in private insurance plans in the US.

METHODS

Eligible subjects were identified from the IBM MarketScan Databases between 2009 and 2017. Individuals 18 years and older, undergoing a single-level CDR or ACDF for cervical radiculopathy and/or myelopathy, were identified. US Census divisions were used to classify the region where surgery was performed. Two-level mixed-effects regression modeling was used to study regional differences in proportional utilization of CDR, while controlling for confounding by regional case-mix differences.

RESULTS

A total of 47,387 subjects met the inclusion criteria; 3553 underwent CDR and 43,834 underwent ACDF. At a national level, the utilization of single-level CDR rose from 5.6 cases for every 100 ACDFs performed in 2009 to 28.8 cases per 100 ACDFs in 2017. The most substantial increases occurred from 2013 onward. The region of highest utilization was the Mountain region (Arizona, Colorado, Idaho, Montana, Nevada, New Mexico, Utah, and Wyoming), where 14.3 CDRs were performed for every 100 ACDFs (averaged over the 9-year period of study). This is in contrast to the East South Central region (Alabama, Kentucky, Mississippi, and Tennessee), where only 2.1 CDRs were performed for every 100 ACDFs. Patient factors that significantly increased the odds of undergoing a CDR were age younger than 40 years (OR 15.9 [95% CI 10.0–25.5]; p < 0.001), no clinical evidence of myelopathy/myeloradiculopathy (OR 1.5 [95% CI 1.4–1.7]; p < 0.001), and a Charlson Comorbidity Index score of 0 (OR 2.7 [95% CI 1.7–4.2]; p < 0.001). After controlling for these factors, significant differences in utilization rates remained between regions (chi-square test = 830.4; p < 0.001).

CONCLUSIONS

This US national level study lends insight into the rate of uptake and geographic differences in utilization of the single-level CDR procedure. Further study will be needed to ascertain specific factors that predict adoption of this technology to explain observed geographic discrepancies.

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Waleed Brinjikji, Elisa Colombo and Giuseppe Lanzino

OBJECTIVE

Vascular malformations of the cervical spine are exceedingly rare. To date there have been no large case series describing the clinical presentation and angioarchitectural characteristics of cervical spine vascular malformations. The authors report their institutional case series on cervical spine vascular malformations diagnosed and treated at their institution.

METHODS

The authors retrospectively reviewed all patients with spinal vascular malformations from their institution from January 2001 to December 2018. Patients with vascular malformations of the cervical spine were included. Lesions were characterized by their angioarchitectural characteristics by an interventional neuroradiologist and endovascular neurosurgeon. Data were collected on clinical presentation, imaging findings, treatment outcomes, and long-term follow-up. Descriptive statistics are reported.

RESULTS

Of a total of 213 patients with spinal vascular malformations, 27 (12.7%) had vascular malformations in the cervical spine. The mean patient age was 46.1 ± 21.9 years and 16 (59.3%) were male. The most common presentations were lower-extremity weakness (13 patients, 48.1%), tetraparesis (8 patients, 29.6%), and lower-extremity sensory dysfunction (7 patients, 25.9%). Nine patients (33.3%) presented with hemorrhage. Fifteen patients (55.6%) had modified Rankin Scale scores of 0–2 at the time of diagnosis. Regarding angioarchitectural characteristics, 8 patients (29.6%) had intramedullary arteriovenous malformations (AVMs), 5 (18.5%) had epidural arteriovenous fistulas (AVFs), 4 (14.8%) had paraspinal fistulas, 4 (14.8%) had mixed epidural/intradural fistulas, 3 (11.1%) had perimedullary AVMs, 2 (7.4%) had dural fistulas, and 1 patient (3.7%) had a perimedullary AVF.

CONCLUSIONS

This retrospective study of 27 patients with cervical spine vascular malformations is the largest series to date on these lesions. The authors found substantial angioarchitectural heterogeneity with the most common types being intramedullary AVMs followed by epidural AVFs, paraspinal fistulas, and mixed intradural/extradural fistulas. Angioarchitecture dictated the clinical presentation as intradural shunts were more likely to present with hemorrhage and acute onset myelopathy, while dural and extradural shunts presented as either incidental lesions or gradually progressive congestive myelopathy.

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Rune T. Paulsen, Jan Sørensen, Leah Y. Carreon and Mikkel Ø. Andersen

OBJECTIVE

The aim of this study was to examine whether routine referral to municipal postoperative rehabilitation is cost-effective in comparison to no referral after surgery for lumbar disc herniation (LDH).

METHODS

One hundred forty-six patients scheduled for primary discectomy due to LDH were included. This secondary analysis, based on data from a previous randomized controlled trial, compared costs and quality-adjusted life years (QALYs) between two groups of patients recovering from LDH surgery: one group of patients received a referral for municipal physical rehabilitation (REHAB) and the other group was sent home without a referral to any postoperative rehabilitation (HOME). Primary outcomes were QALYs calculated from the EQ-5D utility score, societal costs, and incremental cost-effectiveness ratios (ICERs). The main cost-effectiveness analysis used intention-to-treat data, whereas sensitivity analyses included as-treated data. Questionnaires were collected after 1, 3, 6, 12, and 24 months postoperatively.

RESULTS

The main cost-effectiveness analysis showed a small, insignificant incremental QALY of 0.021 and an incremental cost of €211.8 for the REHAB group compared to the HOME group, resulting in an ICER of €10,085. In the as-treated sensitivity analysis, the REHAB group had poorer outcomes and higher costs compared to the HOME group.

CONCLUSIONS

Routine referral to municipal physical rehabilitation in patients recovering from LDH surgery was not cost-effective compared to no referral.

Clinical trial registration no.: NCT03505918 (clinicaltrials.gov)

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Ruth Prieto and José María Pascual

The decisive role Dr. Harvey Cushing (1869–1939) played in medicine goes far beyond the development of neurosurgery. His scientific devotion and commitment to patient care made him an ethical model of strict professionalism. This paper seeks to analyze the decisions Cushing made with the challenging case of HW, an adolescent boy with a craniopharyngioma (CP) involving the third ventricle. Cushing’s earlier failure to successfully remove two similar lesions alerted him to the proximity of HW’s tumor and the hypothalamus. Consequently, he decided to use the chiasm-splitting technique for the first time, with the aim of dissecting the CP-hypothalamus boundaries under direct view. Unexpectedly, HW suffered cardiac arrest during the surgery, but Cushing did not give up. He continued with the operation while his assistants performed resuscitation maneuvers. Such determined and courageous action allowed Cushing to succeed in an apparently hopeless case. Cushing’s unwavering willingness to save patients’ lives, even under extreme circumstances, was a fundamental trait defining his identity as a neurosurgeon. Analyzing the way Cushing dealt with HW’s case provides valuable lessons for neurosurgeons today, particularly the importance of assuming proactive attitudes and, in certain cases, making painstaking efforts to overcome daunting situations to save a life.

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Jayme Augusto Bertelli, Sushil Nehete, Elisa Cristiana Winkelmann Duarte, Neehar Patel and Marcos Flávio Ghizoni

OBJECTIVE

The authors describe the anatomy of the motor branches of the pronator teres (PT) as it relates to transferring the nerve of the extensor carpi radialis brevis (ECRB) to restore wrist extension in patients with radial nerve paralysis. They describe their anatomical cadaveric findings and report the results of their nerve transfer technique in several patients followed for at least 24 months postoperatively.

METHODS

The authors dissected both upper limbs of 16 fresh cadavers. In 6 patients undergoing nerve surgery on the elbow, they dissected the branches of the median nerve and confirmed their identity by electrical stimulation. Of these 6 patients, 5 had had a radial nerve injury lasting 7–12 months, underwent transfer of the distal PT motor branch to the ECRB, and were followed for at least 24 months.

RESULTS

The PT was innervated by two branches: a proximal branch, arising at a distance between 0 and 40 mm distal to the medial epicondyle, responsible for PT superficial head innervation, and a distal motor branch, emerging from the anterior side of the median nerve at a distance between 25 and 60 mm distal to the medial epicondyle. The distal motor branch of the PT traveled approximately 30 mm along the anterior side of the median nerve; just before the median nerve passed between the PT heads, it bifurcated to innervate the deep head and distal part of the superficial head of the PT. In 30% of the cadaver limbs, the proximal and distal PT branches converged into a single trunk distal to the medial epicondyle, while they converged into a single branch proximal to it in 70% of the limbs. The proximal and distal motor branches of the PT and the nerve to the ECRB had an average of 646, 599, and 457 myelinated fibers, respectively.

All patients recovered full range of wrist flexion-extension, grade M4 strength on the British Medical Research Council scale. Grasp strength recovery achieved almost 50% of the strength of the contralateral side. All patients could maintain their wrist in extension while performing grasp measurements.

CONCLUSIONS

The distal PT motor branch is suitable for reinnervation of the ECRB in radial nerve paralysis, for as long as 7–12 months postinjury.

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Elizabeth Schepke, Magnus Tisell, Colin Kennedy, Stephanie Puget, Paolo Ferroli, Mathilde Chevignard, François Doz, Barry Pizer, Stefan Rutkowski, Maura Massimino, Aurora Navajas, Edward Schwalbe, Debbie Hicks, Steven C. Clifford, Torsten Pietsch and Birgitta Lannering

OBJECTIVE

Extensive resection of a tumor in the posterior fossa in children is associated with the risk of neurological deficits. The objective of this study was to prospectively evaluate the short-term neurological morbidity in children after medulloblastoma surgery and relate this to the tumor’s growth pattern and to the extent of resection.

METHODS

In 160 patients taking part in the HIT-SIOP PNET 4 (Hyperfractionated Versus Conventionally Fractionated Radiotherapy in Standard Risk Medulloblastoma) trial, neurosurgeons prospectively responded to questions concerning the growth pattern of the tumor they had resected. The extent of resection (gross, near, or subtotal) was evaluated using MRI. The patients’ neurological status before resection and around 30 days after resection was recorded.

RESULTS

Invasive tumor growth, defined as local invasion in the brain or meninges, cranial nerve, or major vessel, was reported in 58% of the patients. After surgery almost 70% of all patients were affected by one or several neurological impairments (e.g., impaired vision, impaired extraocular movements, and ataxia). However, this figure was very similar to the preoperative findings. Invasive tumor growth implied a significantly higher number of impairments after surgery (p = 0.03) and greater deterioration regarding extraocular movements (p = 0.012), facial weakness (p = 0.048), and ataxia in the arms (p = 0.014) and trunk (p = 0.025) compared with noninvasive tumor growth. This deterioration was not dependent on the extent of resection performed. Progression-free survival (PFS) at 5 years was 80% ± 4% and 76% ± 5% for patients with invasive and noninvasive tumor growth, respectively, with no difference in the 5-year PFS for extent of resection.

CONCLUSIONS

Preoperative neurological impairments and invasive tumor growth were strong predictors of deterioration in short-term neurological outcome after medulloblastoma neurosurgery, whereas the extent of resection was not. Neither tumor invasiveness nor extent of resection influenced PFS. These findings support the continuation of maximal safe resection in medulloblastoma surgery where functional risks are not taken in areas with tumor invasion.

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Keyan A. Peterson, Christofer D. Burnette, Kyle M. Fargen, Patrick A. Brown, James L. West, Stephen B. Tatter and Stacey Q. Wolfe

The authors report the case of a 30-year-old female patient with suspected Cushing’s disease with an anatomical variation of hypoplastic inferior petrosal sinuses and nearly exclusive anterior drainage from the cavernous sinus, who underwent external jugular venous blood sampling with successful disease confirmation and microadenoma localization. The patient presented with signs and symptoms consistent with Cushing’s syndrome, but with discordant preliminary diagnostic testing. She underwent attempted bilateral inferior petrosal sinus sampling; however, she had hypoplastic inferior petrosal sinuses bilaterally and predominantly anterior drainage from the cavernous sinus into the external jugular circulation. Given this finding, the decision was made to proceed with external jugular venous access and sampling in addition to internal jugular venous sampling. A positive adrenocorticotropic hormone (ACTH) response to corticotropin-releasing factor was obtained in the right external jugular vein alone, suggesting a right-sided pituitary microadenoma as the cause of her Cushing’s disease. The patient subsequently underwent a transsphenoidal hypophysectomy that confirmed the presence of a right-sided ACTH-secreting microadenoma, which was successfully resected. She was hypocortisolemic on discharge and has had no signs of recurrence or relapse at 6 months postoperation.

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Gail Rosseau, Walter D. Johnson, Kee B. Park, Peter J. Hutchinson, Laura Lippa, Russell Andrews, Franco Servadei and Roxanna M. Garcia

Global neurosurgery is the practice of neurosurgery with the primary purpose of delivering timely, safe, and affordable neurosurgical care to all who need it. This field is led by neurosurgeons, and global neurosurgery sessions are now part of every major international neurosurgical meeting. The World Federation of Neurosurgical Societies (WFNS) is working to coordinate activities and align all related activities for greater impact. This report updates the contributions made by the WFNS-WHO Liaison Committee at the most recent World Health Assembly (WHA) in 2019. The WHA is a decision-making body of the World Health Organization (WHO), attended by its 194 Member States. The WFNS has maintained official relations as a nongovernmental organization with the WHO for over 30 years, and this year 15 neurosurgical delegates attended events during the WHA. Participation by neurosurgeons continues to grow as many WHA events focused on global surgery have intrinsically involved neurosurgical leadership and participation. This year, resolution WHA72.31, entitled “Emergency and trauma care, Emergency care systems for universal health coverage: ensuring timely care for the acutely ill and injured,” was passed. This resolution provides further opportunities for neurosurgical advocacy as the landscape of global surgery gains recognition and momentum.

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Dang D. T. Can, Jacob R. Lepard, Tran T. Tri, Tran Van Duong, Nguyen T. Thuy, Pham N. Thach, James M. Johnston, W. Jerry Oakes and Tran Dong A

Conjoined twins are a rare congenital abnormality with an estimated incidence of 1:50,000 pregnancies and 1:200,000 live births. Pygopagus twins are characterized by sacrococcygeal fusion that is commonly associated with perineal and spinal abnormalities. Management of this complex disease requires a well-developed surgical system with multidisciplinary capacity and expertise.

A decade ago there were no dedicated pediatric neurosurgeons in southern Vietnam. This has changed within a few short years; there are now 10 dedicated pediatric neurosurgeons with continually expanding technical capacity. In August 2017 a multidisciplinary surgical and anesthetic team successfully separated female pygopagus twins with fused sacrum and spinal cord with associated myelomeningocele defect.

The authors present here the first successful separation of pygopagus twins in Vietnam as a representative case of gradual and sustainable pediatric neurosurgical scale-up.