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1. Avila MJ, Hurlbert RJ. Central cord syndrome redefined. Neurosurg Clin N Am 2021;32:35 3–63. Available from: https://doi.org/10.1016/j.nec.2021.03.007

The pathophysiology of CCS typically occurs in the setting of preexisting stenosis and involves a low-impact/low-velocity hyperextension injury to the neck. This causes buckling of the ligamentum flavum at the lordotic apex of the cervical spine (C4-C6) resulting in spinal cord compression against osteophytes and disks protruding into the anterior canal, displacing the spinal cord parenchyma into the less stenotic lateral recesses. The epicenter of compression is in the sagittal midline but spreads laterally proportional to the force involved and degree of preexisting stenosis. Spinal cord gray matter is affected first because of stretch and shear to the transversely oriented sensory afferents crossing the midline and the arteriole blood supply; their side-to-side horizontal trajectory makes them more susceptible to damage from lateral displacement than the longitudinally oriented white matter tracts. Gray matter injury results in sensory disturbance to the hands. With higher injury forces shear and contusion extend laterally to involve white matter tracts in a medial to- lateral preference. Motor weakness of the hands is precipitated from indiscriminate lateral corticospinal pathway involvement. With greater injury force there is additional lateral, anterior, and posterior white matter involvement affecting arm, leg, bowel, and bladder function.

Of all the controversies surrounding CCS, the management of incomplete SCI in this setting is one of the most widely debated. In his original narrative, Schneider and coworkers described the surgical management of CCS to be “contraindicated because spontaneous improvement or complete recovery may occur. Furthermore, operation has actually been known to harm these patients rather than improve them.” In the 65 years ensuing since this warning, the philosophy of a more conservative approach toward surgical intervention for CCS continues to be championed and despaired.

Even more widely debated than the need for decompressive surgery in CCS, is the timing of surgery. It is generally accepted that incomplete SCI from fracture dislocation should be treated by early decompression and stabilization. However, timing of surgery for incomplete CCS in the absence of acute fracture or dislocation varies widely from one institution and one surgeon to another. Some surgeons prefer to manage their patients’ weeks or months beyond the acute injury phase after they achieve a neurologic plateau. Evidence is limited and controversy common.

6 figures with MR

2. Harris L, Rajashekar D, Sharma P, et al. Performance of computed tomography-guided spine biopsy for the diagnosis of malignancy and infection. Oper Neurosurg 2021;21:12 6–30

Retrospective study of all consecutive patients who underwent a CT-guided spine biopsy at a UK teaching hospital between April 2012 and February 2019. Biopsies were performed by 3 consultant neuroradiologists for a lesion suggestive of either malignancy or infection. Data collection included patient factors, biopsy factors, further investigations required, and diagnosis. Data were analyzed using contingency tables, analysis of variance, unpaired t-test, chi-squared test, and Fisher’s exact test.

A total of 124 percutaneous biopsies were performed on 109 patients with a mean follow-up of 34.5 mo and a mean age of 66 yr. Approximately 32.3% (n = 40) of the biopsies investigated possible infection, and 67.7% investigated malignancy. The sensitivity for infected cases was 37.0%, and for malignancy 72.7%. The diagnostic accuracy was 57.5% and 78.6%, respectively. Complication rate was 1.6%. Neither needle gauge, anatomic level of the biopsy, or bone quality significantly affected the rate of positive biopsy.

In the cases where the CT-guided biopsy was nondiagnostic, a diagnosis was achieved by open biopsy (in 37.5% of cases), repeat CT-guided biopsy (31.3%), further blood cultures (25.0%), and repeat imaging (6.3%).

CT-guided biopsy has a vastly superior sensitivity for malignancy compared with suspected infection. These procedures may be painful, poorly tolerated, and are not entirely risk free. As such the authors advocate judicious use of this modality particularly in cases of suspected infection.

2 figures, 3 tables, no imaging

3. Wang SS, Selge F, Sebök M, et al. The value of intraoperative MRI in recurrent intracranial tumor surgery. J Neurosurg 2020;135(August):1–8

Identifying tumor remnants in previously operated tumor lesions remains a challenge. Intraoperative MRI (ioMRI) helps the neurosurgeon to reorient and update image guidance during surgery. The purpose of this study was to analyze whether ioMRI is more efficient in detecting tumor remnants in the surgery of recurrent lesions compared with primary surgery.

The cohort was divided into two groups: re-craniotomy and primary craniotomy. In contrast-enhancing tumors, tumor suspicion in ioMRI was defined as contrast enhancement in T1-weighted imaging. In non–contrast-enhancing tumors, tumor suspicion was defined as hypointensity in T1-weighted imaging and hyperintensity in T2-weighted imaging and FLAIR. In cases in which the ioMRI tumor suspicion was a false positive and not confirmed during in situ inspection by the neurosurgeon, the signal was defined as a tumor imitating ioMRI signal (TIM).

A total of 214 tumor surgeries met the inclusion criteria. The re-craniotomy group included 89 surgeries, and the primary craniotomy group included 123 surgeries.

The incidence of false-positive tumor imitating ioMRI signal was significantly higher in the re-craniotomy group (n = 11, 12%) compared with the primary craniotomy group (n = 5, 4%; p = 0.015), and in contrast-enhancing tumors was related to hemorrhages in situ.

The differentiation and identification of tumor remnants in surgery of recurrent tumor lesions is more challenging. There was evidence for a significantly increased incidence of tumor imitating ioMRI signal in the re-craniotomy group in comparison with the primary craniotomy group in this study. Most of these false-positive signals were contrast-enhancing signals, which in situ turned out to be hemorrhages. Hyperacute hemorrhage is difficult to distinguish in MRI sequences based on contrast enhancement. The usage of an SWI sequence for differentiation between residual tumor and hemorrhage during ioMRI could be advisable.

4 tables, 2 figures including MR

4. Shlobin NA, Shah VN, Chin CT, et al. Cerebrospinal fluid-venous fistulas: a systematic review and examination of individual patient data. Neurosurgery 2021;88:93 1–41. Available from: https://academic.oup.com/neurosurgery/article/88/5/931/6094070

SIH is an increasingly investigated cause of headaches. CSF leaks precipitate SIH due to resulting CSF hypovolemia. Decreased CSF volume leads to loss of CSF “buoyancy” on the brain, promoting traction or altering the integrity of the pain sensitive structures of the brain. Together with compensatory dilatation of intracranial venous structures, this causes headaches with orthostatic components. Traction, distortion, or compression of diencephalon, mesencephalon, brain lobes, and cranial nerves may result in the other symptoms of SIH. Compression of the eighth cranial nerve or altered pressure in inner ear perilymph or endolymph may result in cochleovestibular symptoms. Direct fistulae between the subarachnoid space and spinal epidural veins represent the most recently discovered cause of SIH.

Schievink et al have proposed a classification of spontaneous spinal CSF leaks contributing to SIH, with type 1a as ventral CSF leaks, type 1b as posterolateral CSF leaks, type 2a as simple meningeal diverticula, type 2b as complex meningeal diverticula or dural ectasia, and type 3 as direct CSF-venous fistulas. Type 3 CSF leaks were not associated with extradural CSF collections. Notably, nearly one-third of patients in their study had an indeterminate, of which greater than half had extradural CSF collections.

The authors conducted a systematic review using PubMed, Embase, Scopus, and Web of Science databases to identify studies discussing CSF-venous fistulas. Titles and abstracts were screened. Studies meeting prespecified inclusion criteria were reviewed in full.

Of 180 articles identified, 16 articles met inclusion criteria. Individual patient data was acquired from 7 studies reporting on 18 patients. CSF-venous fistula most frequently presented as positional headache. Digital subtraction myelography provided greatest detection of CSF-venous fistula in the lateral decubitus position and detected CSF-venous fistula in all individual patient cases. Dynamic computed tomography (CT) myelogram enabled detection and differentiation of CSF-venous fistulas from low-flow epidural leaks. The majority of fistulas were in the thoracic spine and slightly more common on the ri