1. Wu KY, Spinner RJ, Shin AY. Traumatic brachial plexus injury: diagnosis and treatment. Curr Opin Neurol. 2022;35(6):708-717. doi:10.1097/WCO.0000000000001124
A comprehensive physical examination aids in localizing (preganglionic or postganglionic) and characterizing the severity of injury (partial or complete). This is crucial to prognostication and determining the optimal reconstructive strategy. A preganglionic injury indicates an avulsion of the rootlets from the spinal cord, precludes the use of that spinal nerve as a donor for nerve grafting, and limits the reconstructive options available. In contrast, a postganglionic injury indicates a lesion distal to the dorsal root ganglion and still affords the possibility of reconstruction with nerve grafts.
The authors institutional preference is to use CT myelography with a multidetector row CT scanner. This allows for submillimeter resolution of the cervical rootlets, which typically measure 1mm in thickness. The classic pathognomic findings of preganglionic BPI are signs of root avulsion and pseudomeningocele formation. Traumatic pseudomeningocele formation results from bulging of the cerebrospinal fluid (CSF)-containing arachnoid membrane through a dural tear. Pseudomeningoceles can also occur in the absence of root avulsions, and therefore, must be correlated with the patient’s clinical examination. Pseudomeningocele formation occurs between 1- and 3-weeks following injury and delaying CT myelography or MRI will provide a higher diagnostic yield. MR neurography allows for greater soft tissue resolution and the ability to image the spinal cord and postganglionic brachial plexus. Diffusion-weighted MR neurography heavily suppresses background body signals to selectively visualize and highlight tissues, such as nerves, with a long T2 relaxation time. High resolution FIESTA neurography had a 93% accuracy, 84% sensitivity, and 96% specificity in predicting a healthy C5 spinal root amenable for grafting. Additionally, MR provides information on the surrounding soft tissues including cervical spinal cord injury and muscle denervation.
4 figures, 1 table. 48 references with recommended readings.
2. Broekema AEH, Simões de Souza NF, Soer R, et al. Noninferiority of Posterior Cervical Foraminotomy vs Anterior Cervical Discectomy With Fusion for Procedural Success and Reduction in Arm Pain Among Patients With Cervical Radiculopathy at 1 Year. JAMA Neurol. 2023;80(1):40. doi:10.1001/jamaneurol.2022.4208
The Foraminotomy ACDF Cost-Effectiveness Trial (FACET) was designed to compare the clinical- and cost-effectiveness of posterior vs anterior surgery in patients with cervical radiculopathy due to foraminal nerve root compression. Posterior surgery was hypothesized to be noninferior to anterior surgery. The trial includes a follow-up of 2 years. The current study presents the clinical effectiveness results at 1 year of follow-up.
This multicenter investigator-blinded noninferiority randomized clinical trial was conducted from January 2016 to May 2020 with a total follow-up of 2 years. Patients were included from 9 hospitals in the Netherlands. Of 389 adult patients with 1-sided single-level cervical foraminal radiculopathy screened for eligibility, 124 declined to participate or did not meet eligibility criteria. Patients with pure axial neck pain without radicular pain were not eligible. Of 265 patients randomized (132 to posterior and 133 to anterior), 15 were lost to follow-up and 228 were included in the 1-year analysis.
Primary outcomes were proportion of success using Odom criteria and decrease in arm pain using a visual analogue scale from 0 to 100 with a noninferiority margin of 10%. Secondary outcomes were neck pain, disability, quality of life, work status, treatment satisfaction, reoperations, and complications.
Among 265 included patients, the mean (SD) age was 51.2 (8.3) years; 133 patients (50%) were female and 132 (50%) were male. Patients were randomly assigned to posterior (132) or anterior (133) surgery. The proportion of success was 0.88 (86 of 98) in the posterior surgery group and 0.76 (81 of 106) in the anterior surgery group and the between-group difference in arm pain was −2.8 at 1-year follow-up, indicating noninferiority of posterior surgery. Decrease in arm pain had a between-group difference of 3.4, crossing the noninferiority margin with 1.8 points.
These findings suggest noninferiority of posterior surgery compared to anterior surgery and may be used to inform patient counseling and shared decision-making between physicians and patients with 1-sided foraminal radiculopathy.
3 tables, 2 figures, no imaging
3. Mitchell P, Lee SCM, Yoo PE, et al. Assessment of Safety of a Fully Implanted Endovascular Brain-Computer Interface for Severe Paralysis in 4 Patients. JAMA Neurol. Published online January 9, 2023:1-9. doi:10.1001/jamaneurol.2022.4847
Case reports of investigational BCI devices have described control of exoskeletons, prosthetic limbs, and communication technologies and demonstrated the ability to directly decode speech and handwriting from cortical motor activity. Application to wider patient populations is limited, in part by the invasiveness of craniotomy or partial skull removal to implant electrodes in or on the brain. The blood vessels of the brain offer a less invasive route for obtaining access to the motor cortex. Venous stenting has routinely been performed for treating idiopathic intracranial hypertension in the transverse sinus, with a major complication rate of less than 2%. An endovascular device incorporating recording electrodes and implantable in the superior sagittal sinus has recently been developed (Stentrode; Synchron).
The Stentrode With Thought-Controlled Digital Switch (SWITCH) study, a single-center, prospective, first in-human study, evaluated 5 patients with severe bilateral upper-limb paralysis, with a follow-up of 12 months. From a referred sample, 4 patients with amyotrophic lateral sclerosis and 1 with primary lateral sclerosis met inclusion criteria and were enrolled in the study. Surgical procedures and follow-up visits were performed at the Royal Melbourne Hospital, Parkville, Australia. Training sessions were performed at patients’ homes and at a university clinic. The study start date was May 27, 2019, and final follow-up was completed January 9, 2022.
In this prospective, open-label, first in-human study conducted in Australia, an endovascular motor neuroprosthesis BCI implanted in the SSS of 4 patients with severe paralysis was associated with no serious adverse events and no occlusion of target vessels or device migration during the 12-month follow-up period. The BCI maintained a stable signal through- out the study, and all participants successfully controlled a computer with the BCI. Endovascular access to the sensorimotor cortex offers an alternative to BCI technologies, where electrodes are placed in or on the dura by open-brain surgery.
3 figures
4. Hara T, Matsushige T, Yoshiyama M, Hashimoto Y, Kobayashi S, Sakamoto S. Association of circumferential aneurysm wall enhancement with recurrence after coiling of unruptured intracranial aneurysms: a preliminary vessel wall imaging study. J Neurosurg. 2022;138(January):1-7. doi:10.3171/2022.4.jns22421
Recent histopathological studies of unruptured intracranial aneurysms (UIAs) have confirmed that aneurysm wall enhancement (AWE) on MR vessel wall imaging (VWI) is related to wall degeneration with in vivo inflammatory cell infiltration. Therefore, pretreatment aneurysm wall status on VWI may be associated with recurrence after endovascular treatment.
VWI with gadolinium was performed on 67 consecutive saccular unruptured intracranial aneurysms before endovascular treatment between April 2017 and June 2021. The mean (range) follow-up period after treatment was 24.4 months. AWE patterns were classified as circumferential AWE (CAWE), focal AWE (FAWE), and negative AWE (NAWE).
AWE patterns were as follows: 10 CAWE (14.9%), 20 FAWE (29.9%), and 37 NAWE (55.2%). Follow-up MRA detected aneurysm recurrence in 18 of 69 cases (26.1%). Univariate analysis identified maximum diameter (5.8 mm in patients with stable aneurysms vs 7.7 mm in those with unstable aneurysms), aspect ratio, aneurysm location in posterior circulation (4.1% vs 27.8%), volume embolization ratio, and AWE pattern as significant predictive factors of recurrence. Among the 3 AWE patterns, CAWE was significantly more frequent in the unstable group, but no significant differences in stability of the treated aneurysms were observed with the FAWE and NAWE patterns. In multivariate logistic regression analysis, CAWE pattern and volume embolization ratio ≥ 25% remained as significant factors associated with aneurysm stability after coiling.
They conclude that the CAWE pattern, which suggests a specific feature of aneurysm wall degeneration, may negatively affect the durability of coiled aneurysms. Although the long-term stability of coiled aneurysms and the requirement for retreatment currently remain unclear, VWI before coiling provides novel insights into the stability of coiled aneurysms.
3 tables, 3 figures with angio and MR
5. Hasegawa H, Inoue A, Helal A, Kashiwabara K, Meyer FB. Pineal cyst: results of long-term MRI surveillance and analysis of growth and shrinkage rates. J Neurosurg. 2022;138(January):1-7. doi:10.3171/2022.4.jns22276
Pineal cyst (PC) is a common abnormality located adjacent to or within the pineal gland. Several previous studies reported the prevalence to be 1%–4%; however, it appears that these studies were based on a somewhat biased population that had neurosurgical/ neurological concerns. In fact, the real prevalence of PC among asymptomatic healthy volunteers has been reported to be as low as 0.2%. Radiologically, PC is usually delineated as a simple cyst with a thin, smooth, contrasted wall measuring up to 2 mm. Atypical findings including internal septations, thicker wall with nodularity, multilobulated shape, and multicystic appearance are possible. Signal intensity (SI) on MRI is variable depending on the cyst components, although usually it is similar but slightly hyperintense to CSF on T1-weighted and FLAIR images.
The goals of this study were to evaluate the long-term natural history of PC and elucidate risk factors for cyst growth and shrinkage, using our electronic database with long-term follow-up.
The records and MRI of 409 consecutive patients with PC were retrospectively examined (nonsurgical cohort). Cyst growth and shrinkage were defined as a ≥ 2-mm increase and decrease in cyst diameter in any direction, respectively.
The median radiological follow-up period was 10.7 years. The median change in maximal diameter was −0.6 mm. During the observation period, cyst growth was confirmed in 21 patients (5.1%). Multivariate logistic regression analysis revealed that only age was significantly associated with cyst growth. No patient required resection during the observation period. Cyst shrinkage was confirmed in 57 patients (13.9%). Multivariate analysis revealed that maximal diameter and cyst CSF T2 signal intensity ratio were significantly associated with cyst shrinkage.
They conclude that only 5% of PCs, mainly in patients younger than 50 years of age, have the potential to grow, while cyst shrinkage is more likely to occur across all age groups. Younger age is associated with cyst growth, while larger diameter and higher signal intensity on T2-weighted imaging are associated with shrinkage. Surgery is rarely needed.
3 tables, 3 figures, with MR
6. Xiong GX, Collins JE, Ferrone ML, Schoenfeld AJ. Prospective comparison of 1-year survival in patients treated operatively and non-operatively for spinal metastatic disease: results of the prospective observational study of spinal metastasis treatment (POST). Spine Journal. 2022;23(1):14-17. doi:10.1016/j.spinee.2022.02.004
A major change occurred in the field of spine surgery in 2005 following the landmark publication of Patchell et al. regarding the efficacy of spine surgery for restoration of ambulatory function in patients with spinal metastatic disease. In the succeeding 15 years, enthusiasm grew for surgical interventions as a standard treatment option for patients with spinal metastases. Several investigations touted that surgery not only preserved ambulatory ability but also improved survival. There was a concern that many of these investigations were confounded by selection bias and controversy remains regarding the utility of spine surgery in subsets of patients with spinal metastases based on baseline neurologic status. To address this, the authors planned an analysis that accounted for confounding by indication and compared patients treated operatively and nonoperatively for spinal metastases within the Prospective Observational study of Spinal metastasis Treatment (POST). The authors hypothesized that patients treated surgically would have superior one-year survival to those managed nonoperatively.
87 instances of surgical intervention and 122 cases of nonoperative treatment were included. The average age of both cohorts approximated 60.5 years. Lung cancer was the most common primary tumor (20%), followed by breast (16%) and prostate (14%). The thoracic spine was the most common site of surgical intervention (70%). Most surgeries consisted of fusion-based procedures (79%), including 26 corpectomies. Combined chemotherapy and radiation was the most common nonoperative modality (80%).
Overall, 50% of the cohort died by 1-year following presentation (105/209). In the operative group, the mortality rate was 46% at 1-year, as compared to 54% in the nonoperative cohort. This represented a 25% reduction in the odds of mortality but was not significantly different. Following propensity score adjustment, accounting for confounding by indication in the decision for surgery, surgical intervention offered a 28% reduction in the odds of mortality but still did not demonstrate statistical significance.
They conclude that their findings add to a growing body of evidence that indicates surgical intervention is not uniformly beneficial across all individuals with spinal metastases. Although the benefits of surgery for patients with neurologic deficits, acute loss of ambulatory function, and spinal instability are incontrovertible, robust evidence is lacking for those without neurologic compromise or impaired ambulatory function.
1 figure, 1 table
7. Alhammoud A, Korytkowski PD, Lavelle WF, Metkar US. Proximal junctional kyphosis in adult spinal deformity: An up-to-date review. Semin Spine Surg. 2022;34(4):100992. doi:10.1016/j.semss.2022.100992
The formal definition of proximal junctional kyphosis is the criteria of 1) a proximal junctional angle (PJA) of greater than or equal to 10° and 2) a proximal junctional angle greater than 10°compared to preoperative measurements. Typically, the PJA is defined as the angle between the lower endplate of the upper instrumented vertebra (UIV) and the upper endplate of two vertebrae above the UIV (UIV + 2). Other studies have used different values to define PJA such as 15° and 20°. Additionally, some papers have used upper instrumented vertebra +2 or UIV + 1 to measure the PJA. Both methods for measuring the PJA have demonstrated adequate reproducibility.
Many risk factors for proximal junctional kyphosis have been identified. Patient-specific risk factors include higher body mass index (BMI), older age, presence of a comorbidity, male sex, low bone mineral density (BMD), and osteoporosis. There is evidence for sarcopenia as a risk factor by observing decreased muscle volume at the T10 to L2 level in proximal junctional kyphosis patients. Measuring the psoas cross-sectional area is another method that can indicate sarcopenia as a risk factor for PJK.
2 figures, 1 table. Really one figure, since the lone figure is duplicated in the paper….a rather unusual copyediting failure in my experience.
8. Fuentes AM, Khalid SI, Mehta AI. Predictors of Subsequent Intervention After Middle Meningeal Artery Embolization for Treatment of Subdural Hematoma: A Nationwide Analysis. Neurosurgery. 2023;92(1):144-149. doi:10.1227/neu.0000000000002151
Middle meningeal artery (MMA) embolization has recently emerged as an effective technique to treat subdural hematomas (SDHs). Studies to date have been limited, largely, to single-center studies with limited follow-up and have not assessed subsequent surgical interventions and factors associated with these interventions.
Using an all-payer claims database patients who underwent MMA embolization between January 2010 and October 2020 after the diagnosis of SDH were identified. Rates of post-MMA embolization surgical interventions, including craniotomy and burr hole drainage, were accessed within 5 years following.
A total of 322 patients were included. Of this cohort, 55 (17.1%) required subsequent intervention within 5 years, with 36 (11.2%) receiving burr hole evacuation and 19 (5.9%) receiving craniotomy. Factor Xa inhibitor use was independently associated with subsequent interventions after MMA embolization procedures. Of the other patient factors evaluated, including age, sex, comorbidity status, and use of vitamin K antagonists, antiplatelets, and factor Xa inhibitors, none were found to be significantly associated with future interventions.
Patients taking factor Xa inhibitors are at especially high risk of subsequent intervention after MMA embolization. In this cohort, factor Xa inhibitor use, but not vitamin K antagonist or antiplatelet use, was significantly associated with increased odds of subsequent intervention within 5 years. Xa inhibitors include Xarelto, Eliquis.
1 table, 1 figure, no imaging
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