Incidental durotomy resulting in a postoperative lumbosacral nerve root with eventration into the adjacent facet joint: illustrative cases.

BACKGROUND: Radicular pain after lumbar decompression surgery can result from epidural hematoma/seroma, recurrent disc herniation, incomplete decompression, or other rare complications. A less recognized complication is postoperative nerve root herniation, resulting from an initially unrecognized intraoperative or, more commonly, a spontaneous postoperative durotomy. Rarely, this nerve root herniation can become entrapped within local structures, including the facet joint. The aim of this study was to illustrate our experience with three cases of lumbosacral nerve root eventration into an adjacent facet joint and to describe our diagnostic and surgical approach to this rare complication. OBSERVATIONS: Three patients who had undergone lumbar decompression surgery with or without fusion experienced postoperative radiculopathy. Exploratory revision surgery revealed all three had a durotomy with nerve root eventration into the facet joint. Significant symptom improvement was achieved in all patients following liberation of the neural elements from the facet joints. LESSONS: Entrapment of herniated nerve roots into the facet joint may be a previously underappreciated complication and remains quite challenging to diagnose even with the highest-quality advanced imaging. Thus, clinicians must have a high index of suspicion to diagnose this issue and a low threshold for surgical exploration.

[1-11C]-Butanol Positron Emission Tomography reveals an impaired brain to nasal turbinates pathway in aging amyloid positive subjects.

BACKGROUND: Reduced clearance of cerebrospinal fluid (CSF) has been suggested as a pathological feature of Alzheimer's disease (AD). With extensive documentation in non-human mammals and contradictory human neuroimaging data it remains unknown whether the nasal mucosa is a CSF drainage site in humans. Here, we used dynamic PET with [1-11C]-Butanol, a highly permeable radiotracer with no appreciable brain binding, to test the hypothesis that tracer drainage from the nasal pathway reflects CSF drainage from brain. As a test of the hypothesis, we examined whether brain and nasal fluid drainage times were correlated and affected by brain amyloid. METHODS: 24 cognitively normal subjects (≥ 65 years) were dynamically PET imaged for 60 min. using [1-11C]-Butanol. Imaging with either [11C]-PiB or [18F]-FBB identified 8 amyloid PET positive (Aß+) and 16 Aß- subjects. MRI-determined regions of interest (ROI) included: the carotid artery, the lateral orbitofrontal (LOF) brain, the cribriform plate, and an All-turbinate region comprised of the superior, middle, and inferior turbinates. The bilateral temporalis muscle and jugular veins served as control regions. Regional time-activity were used to model tracer influx, egress, and AUC. RESULTS: LOF and All-turbinate 60 min AUC were positively associated, thus suggesting a connection between the brain and the nose. Further, the Aß+ subgroup demonstrated impaired tracer kinetics, marked by reduced tracer influx and slower egress. CONCLUSION: The data show that tracer kinetics for brain and nasal turbinates are related to each other and both reflect the amyloid status of the brain. As such, these data add to evidence that the nasal pathway is a potential CSF drainage site in humans. These data warrant further investigation of brain and nasal contributions to protein clearance in neurodegenerative disease.

Deep-learning reconstructed lumbar spine 3D MRI for surgical planning: pedicle screw placement and geometric measurements compared to CT.

PURPOSE: To test equivalency of deep-learning 3D lumbar spine MRI with "CT-like" contrast to CT for virtual pedicle screw planning and geometric measurements in robotic-navigated spinal surgery. METHODS: Between December 2021 and June 2022, 16 patients referred for spinal fusion and decompression surgery with pre-operative CT and 3D MRI were retrospectively assessed. Pedicle screws were virtually placed on lumbar (L1-L5) and sacral (S1) vertebrae by three spine surgeons, and metrics (lateral deviation, axial/sagittal angles) were collected. Vertebral body length/width (VL/VW) and pedicle height/width (PH/PW) were measured at L1-L5 by three radiologists. Analysis included equivalency testing using the 95% confidence interval (CI), a margin of ± 1 mm (± 2.08° for angles), and intra-class correlation coefficients (ICCs). RESULTS: Across all vertebral levels, both combined and separately, equivalency between CT and MRI was proven for all pedicle screw metrics and geometric measurements, except for VL at L1 (mean difference: - 0.64 mm; [95%CI - 1.05, - 0.24]), L2 (- 0.65 mm; [95%CI - 1.11, - 0.20]), and L4 (- 0.78 mm; [95%CI - 1.11, - 0.46]). Inter- and intra-rater ICC for screw metrics across all vertebral levels combined ranged from 0.68 to 0.91 and 0.89-0.98 for CT, and from 0.62 to 0.92 and 0.81-0.97 for MRI, respectively. Inter- and intra-rater ICC for geometric measurements ranged from 0.60 to 0.95 and 0.84-0.97 for CT, and 0.61-0.95 and 0.93-0.98 for MRI, respectively. CONCLUSION: Deep-learning 3D MRI facilitates equivalent virtual pedicle screw placements and geometric assessments for most lumbar vertebrae, with the exception of vertebral body length at L1, L2, and L4, compared to CT for pre-operative planning in patients considered for robotic-navigated spine surgery.

Robot-Assisted Lumbar Pedicle Screw Placement Based on 3D Magnetic Resonance Imaging.

STUDY DESIGN: Human Cadaveric Study. OBJECTIVE: This study aims to explore the feasibility of using preoperative magnetic resonance imaging (MRI), zero-time-echo (ZTE) and spoiled gradient echo (SPGR), as source data for robotic-assisted spine surgery and assess the accuracy of pedicle screws. METHODS: Zero-time-echo and SPGR MRI scans were conducted on a human cadaver. These images were manually post-processed, producing a computed tomography (CT)-like contrast. The Mazor X robot was used for lumbar pedicle screw-place navigating of MRI. The cadaver underwent a postoperative CT scan to determine the actual position of the navigated screws. RESULTS: Ten lumbar pedicle screws were robotically navigated of MRI (4 ZTE; 6 SPGR). All MR-navigated screws were graded A on the Gertzbein-Robbins scale. Comparing preoperative robotic planning to postoperative CT scan trajectories: The screws showed a median deviation of overall 0.25 mm (0.0; 1.3), in the axial plane 0.27 mm (0.0; 1.3), and in the sagittal plane 0.24 mm (0.0; 0.7). CONCLUSION: This study demonstrates the first successful registration of MRI sequences, ZTE and SPGR, in robotic spine surgery here used for intraoperative navigation of lumbar pedicle screws achieving sufficient accuracy, showcasing potential progress toward radiation-free spine surgery.

Spontaneous absorption of osteophytic calcification associated with chronic dural tear and ventral spinal CSF leak.

Spontaneous intracranial hypotension (SIH) is associated with cerebrospinal fluid (CSF) hypovolemia, often from a traumatic dural tear from a calcified spinal osteophyte. Visualizing osteophytes on CT imaging can guide decision making on candidate leak sites. We report the atypical case of a 41-year-old woman whose ventral CSF leak was associated with an osteophyte that resorbed over an 18-month period. Full workup and treatment were delayed due to unexpected pregnancy and completion of gestational cycle with delivery of a healthy term infant. The patient initially presented with persistent orthostatic headaches with nausea and blurred vision. Initial MRI suggested brain sagging among other findings consistent with SIH. CT myelogram showed an extensive thoracic CSF leak with a prominent ventral T11-T12 osteophyte and multiple small disc herniations. The patient did not respond to epidural blood patches and deferred additional imaging due to her pregnancy. CT myelography performed 5 months post-partum showed an absence of the osteophyte; a follow-up digital subtraction myelogram performed 10 months post-partum showed evidence of source leak at T11-T12 level. T11-T12 laminectomy visualized and repaired a 5 mm ventral dural defect with symptom resolution. This report highlights the potential for a resorbed osteophyte to be the causative agent for long-standing dural tears that do not show visible calcifications on myelography.

Intravenous Ketorolac Substantially Reduces Opioid Use and Length of Stay After Lumbar Fusion: A Randomized Controlled Trial.

STUDY DESIGN: A randomized, double-blinded, placebo-controlled trial. OBJECTIVE: To examine the effect of intravenous ketorolac (IV-K) on hospital opioid use compared with IV-placebo (IV-P) and IV acetaminophen (IV-A). SUMMARY OF BACKGROUND DATA: Controlling postoperative pain while minimizing opioid use after lumbar spinal fusion is an important area of study. PATIENTS AND METHODS: Patients aged 18 to 75 years undergoing 1 to 2 level lumbar fusions between April 2016 and December 2019 were included. Patients with chronic opioid use, smokers, and those on systemic glucocorticoids or contraindications to study medications were excluded. A block randomization scheme was used, and study personnel, hospital staff, and subjects were blinded to the assignment. Patients were randomized postoperatively. The IV-K group received 15 mg (age > 65) or 30 mg (age < 65) every six hours (q6h) for 48 hours, IV-A received 1000 mg q6h, and IV-P received normal saline q6h for 48 hours. Demographic and surgical details, opioid use in morphine milliequivalents, opioid-related adverse events, and length of stay (LOS) were recorded. The primary outcome was in-hospital opioid use up to 72 hours. RESULTS: A total of 171 patients were included (58 IV-K, 55 IV-A, and 58 IV-P) in the intent-to-treat (ITT) analysis, with a mean age of 57.1 years. The IV-K group had lower opioid use at 72 hours (173 ± 157 mg) versus IV-A (255 ± 179 mg) and IV-P (299 ± 179 mg; P = 0.000). In terms of opiate use, IV-K was superior to IV-A ( P = 0.025) and IV-P ( P = 0.000) on ITT analysis, although on per-protocol analysis, the difference with IV-A did not reach significance ( P = 0.063). When compared with IV-P, IV-K patients reported significantly lower worst ( P = 0.004), best ( P = 0.001), average ( P = 0.001), and current pain ( P = 0.002) on postoperative day 1, and significantly shorter LOS ( P = 0.009) on ITT analysis. There were no differences in opioid-related adverse events, drain output, clinical outcomes, transfusion rates, or fusion rates. CONCLUSIONS: By reducing opioid use, improving pain control on postoperative day 1, and decreasing LOS without increases in complications or pseudarthrosis, IV-K may be an important component of "enhanced recovery after surgery" protocols.

Spontaneous Intracranial Hypotension in Pregnancy.

PURPOSE OF REVIEW: Spontaneous intracranial hypotension (SIH) is a debilitating disease typically featuring orthostatic headache and caused by a spinal CSF leak. This review will describe the characteristics of SIH in pregnant patients and the associated unique management and treatment considerations. RECENT FINDINGS: Herein, a novel case is reported of a 41-year-old woman who presented with SIH pre-conception but saw marked improvement of symptoms after 5 weeks antepartum and symptom recurrence 2 months post-partum. A literature review of SIH in pregnancy revealed 14 reported patients across 10 studies since 2000. All the reported cases resulted in delivery of healthy infants and symptomatic improvement with conservative management or a variety of treatment modalities including non-targeted epidural blood patch (EBP). Clinical and imaging features of SIH in pregnancy are reviewed. We hypothesize an antenatal protective mechanism against SIH symptoms through cephalad redistribution of CSF volume from the spinal to intracranial compartments related to uterine growth and decreased CSF volume within the lumbar cistern. Treatment recommendations are discussed including duration of bed rest and decision for non-targeted multi-site EBPs. When required, non-invasive diagnostic spine MRI using fat-suppressed axial T2-weighted imaging may be helpful.

MRI after Lumbar Spine Decompression and Fusion Surgery: Technical Considerations, Expected Findings, and Complications.

Postoperative MRI of the lumbar spine is a mainstay for detailed anatomic assessment and evaluation of complications related to decompression and fusion surgery. Key factors for reliable interpretation include clinical presentation of the patient, operative approach, and time elapsed since surgery. Yet, recent spinal surgery techniques with varying anatomic corridors to approach the intervertebral disc space and implanted materials have expanded the range of normal (expected) and abnormal (unexpected) postoperative changes. Modifications of lumbar spine MRI protocols in the presence of metallic implants, including strategies for metal artifact reduction, provide important diagnostic information. This focused review discusses essential principles for the acquisition and interpretation of MRI after lumbar spinal decompression and fusion surgery, highlights expected postoperative changes, and describes early and delayed postoperative complications with examples.

Management Algorithm for Osseous Metastatic Disease: What the Treatment Teams Want to Know.

Radiologists play a primary role in identifying, characterizing, and classifying spinal metastases and can play a lifesaving role in the care of these patients by triaging those with instability to urgent spine surgery consultation. For this reason, an understanding of current treatment algorithms and principles of spinal stability in patients with cancer is vital for all who interpret spine studies. In addition, advances in imaging allow radiologists to provide more accurate diagnoses and characterize pathology, thereby improving patient safety.

Cranial MRgFUS intraprocedural diffusion and T2 imaging and comparison with postablation lesion size and location.

OBJECTIVE: The ability to predict final lesion characteristics during magnetic resonance-guided focused ultrasound (MRgFUS) thalamotomy for the treatment of essential tremor remains technically challenging, yet it is essential in order to avoid off-target ablation and to ensure adequate treatment. The authors sought to evaluate the technical feasibility and utility of intraprocedural diffusion-weighted imaging (DWI) in the prediction of final lesion size and location. METHODS: Lesion diameter and distance from the midline were measured on both intraprocedural and immediate postprocedural diffusion and T2-weighted sequences. Bland-Altman analysis was utilized to determine differences in measurement between intraprocedural and immediate postprocedural images with both sequences. RESULTS: Lesion size increased on both the postprocedural diffusion and T2-weighted sequences, although the difference was smaller on the T2-weighted sequence. There was only a small difference in intraprocedural and postprocedural lesion distance from the midline on both the diffusion and T2-weighted sequences. CONCLUSIONS: Intraprocedural DWI is both feasible and useful with regard to predicting final lesion size and providing an early indication of lesion location. Further research should determine the value of intraprocedural DWI in predicting delayed clinical outcomes.

Rapid lumbar MRI protocol using 3D imaging and deep learning reconstruction.

BACKGROUND AND PURPOSE: Three-dimensional (3D) imaging of the spine, augmented with AI-enabled image enhancement and denoising, has the potential to reduce imaging times without compromising image quality or diagnostic performance. This work evaluates the time savings afforded by a novel, rapid lumbar spine MRI protocol as well as image quality and diagnostic differences stemming from the use of an AI-enhanced 3D T2 sequence combined with a single Dixon acquisition. MATERIALS AND METHODS: Thirty-five subjects underwent MRI using standard 2D lumbar imaging in addition to a "rapid protocol" consisting of 3D imaging, enhanced and denoised using a prototype DL reconstruction algorithm as well as a two-point Dixon sequence. Images were graded by subspecialized radiologists and imaging times were collected. Comparison was made between 2D sagittal T1 and Dixon fat images for neural foraminal stenosis, intraosseous lesions, and fracture detection. RESULTS: This study demonstrated a 54% reduction in total acquisition time of a 3D AI-enhanced imaging lumbar spine MRI rapid protocol combined with a sagittal 2D Dixon sequence, compared to a 2D standard-of-care protocol. The rapid protocol also demonstrated strong agreement with the standard-of-care protocol with respect to osseous lesions (κ = 0.88), fracture detection (κ = 0.96), and neural foraminal stenosis (ICC > 0.9 at all levels). CONCLUSION: 3D imaging of the lumbar spine with AI-enhanced DL reconstruction and Dixon imaging demonstrated a significant reduction in imaging time with similar performance for common diagnostic metrics. Although previously limited by long postprocessing times, this technique has the potential to enhance patient throughput in busy radiology practices while providing similar or improved image quality.

Focused ultrasound-mediated blood-brain barrier opening in Alzheimer's disease: long-term safety, imaging, and cognitive outcomes.

OBJECTIVE: MRI-guided low-intensity focused ultrasound (FUS) has been shown to reversibly open the blood-brain barrier (BBB), with the potential to deliver therapeutic agents noninvasively to target brain regions in patients with Alzheimer's disease (AD) and other neurodegenerative conditions. Previously, the authors reported the short-term safety and feasibility of FUS BBB opening of the hippocampus and entorhinal cortex (EC) in patients with AD. Given the need to treat larger brain regions beyond the hippocampus and EC, brain volumes and locations treated with FUS have now expanded. To evaluate any potential adverse consequences of BBB opening on disease progression, the authors report safety, imaging, and clinical outcomes among participants with mild AD at 6-12 months after FUS treatment targeted to the hippocampus, frontal lobe, and parietal lobe. METHODS: In this open-label trial, participants with mild AD underwent MRI-guided FUS sonication to open the BBB in ß-amyloid positive regions of the hippocampus, EC, frontal lobe, and parietal lobe. Participants underwent 3 separate FUS treatment sessions performed 2 weeks apart. Outcome assessments included safety, imaging, neurological, cognitive, and florbetaben ß-amyloid PET. RESULTS: Ten participants (range 55-76 years old) completed 30 separate FUS treatments at 2 participating institutions, with 6-12 months of follow-up. All participants had immediate BBB opening after FUS and BBB closure within 24-48 hours. All FUS treatments were well tolerated, with no serious adverse events related to the procedure. All 10 participants had a minimum of 6 months of follow-up, and 7 participants had a follow-up out to 1 year. Changes in the Alzheimer's Disease Assessment Scale-cognitive and Mini-Mental State Examination scores were comparable to those in controls from the Alzheimer's Disease Neuroimaging Initiative. PET scans demonstrated an average ß-amyloid plaque of 14% in the Centiloid scale in the FUS-treated regions. CONCLUSIONS: This study is the largest cohort of participants with mild AD who received FUS treatment, and has the longest follow-up to date. Safety was demonstrated in conjunction with reversible and repeated BBB opening in multiple cortical and deep brain locations, with a concomitant reduction of ß-amyloid. There was no apparent cognitive worsening beyond expectations up to 1 year after FUS treatment, suggesting that the BBB opening treatment in multiple brain regions did not adversely influence AD progression. Further studies are needed to determine the clinical significance of these findings. FUS offers a unique opportunity to decrease amyloid plaque burden as well as the potential to deliver targeted therapeutics to multiple brain regions in patients with neurodegenerative disorders.

Deep-learning-reconstructed high-resolution 3D cervical spine MRI for foraminal stenosis evaluation.

OBJECTIVE: To compare standard-of-care two-dimensional MRI acquisitions of the cervical spine with those from a single three-dimensional MRI acquisition, reconstructed using a deep-learning-based reconstruction algorithm. We hypothesized that the improved image quality provided by deep-learning-based reconstruction would result in improved inter-rater agreement for cervical spine foraminal stenosis compared to conventional two-dimensional acquisitions. MATERIALS AND METHODS: Forty-one patients underwent routine cervical spine MRI with a conventional protocol comprising two-dimensional T2-weighted fast spin echo scans (2 axial planes, 1 sagittal plane), and an isotropic-resolution three-dimensional T2-weighted fast spin echo scan reconstructed over a 4-h time window with a deep-learning-based reconstruction algorithm. Three radiologists retrospectively assessed images for the degree to which motion artifact limited clinical assessment, and foraminal and central stenosis at each level. Inter-rater agreement was analyzed with weighted Fleiss's kappa (k) and comparisons between two-dimensional and three-dimensional sequences were performed with Wilcoxon signed-rank test. RESULTS: Inter-rater agreement for foraminal stenosis was "substantial" for two-dimensional sequences (k = 0.76) and "excellent" for the three-dimensional sequence (k = 0.81). Agreement was "excellent" for both sequences (k = 0.85 and 0.83) for central stenosis. The three-dimensional sequence had less perceptible motion artifact (p ≤ 0.001-0.036). Mean total scan time was 10.8 min for the two-dimensional sequences, and 7.3 min for the three-dimensional sequence. CONCLUSION: Three-dimensional MRI reconstructed with a deep-learning-based algorithm provided "excellent" inter-observer agreement for foraminal and central stenosis, which was at least equivalent to standard-of-care two-dimensional imaging. Three-dimensional MRI with deep-learning-based reconstruction was less prone to motion artifact, with overall scan time savings.

Intracranial hypotension due to ventral thoracic dural tear secondary to osteophyte complex: resolution after transdural thoracic microdiscectomy with dural repair. Illustrative case.

BACKGROUND: Intracranial hypotension (IH) manifests with orthostatic headaches secondary to cerebrospinal fluid (CSF) hypovolemia. Common iatrogenic etiologies include lumbar punctures and spinal surgery. Although much rarer, structural defects such as osteophytes and herniated calcified discs can violate dural integrity, resulting in CSF leak. OBSERVATIONS: The authors reported the case of a 32-year-old woman who presented with progressively worsening orthostatic headaches. During an extensive examination, magnetic resonance imaging of her thoracic spine revealed a cervicothoracic ventral epidural collection of CSF, prompting a dynamic computed tomography myelogram, which not only helped to confirm severe cerebral hypotension but also suggested underlying pathology of a dorsally projecting disc osteophyte complex at T2-3. Conservative and medical management failed to alleviate symptoms, and a permanent surgical cure was eventually sought. The patient underwent a transdural thoracic discectomy with dural repair, which resulted in resolution of her symptoms. LESSONS: Clear guidelines regarding the management strategy of IH secondary to disc osteophyte complexes are yet to be established. A thorough literature review noted only 24 reported cases between 1998 and 2019, in which 13 patients received surgery. There is a 46% symptom resolution rate with conservative management, lower than that for iatrogenic etiologies. For patients in whom conservative management failed, surgical intervention proved effective in resolving symptoms, with a success rate of 92.3%.

Paramaxillary CT-guided fine needle aspiration of head and neck lesions: technique, diagnostic yield, and safety profile.

Computed tomography (CT)-guided percutaneous biopsy of deep-seated head and neck lesions can be a less invasive and equally effective alternative to surgical techniques. There are multiple approaches for needle biopsy that target varying spaces within the head and neck while successfully avoiding critical anatomy. In the paramaxillary approach, the needle is advanced through the infrazygomatic buccal space, in between the maxilla and mandible. In this study, we examine the safety and diagnostic yield of FNA without core needle biopsy performed via the paramaxillary approach in 19 patients yielding 20 fine needle aspirates between 2014 and 2022. Of the fine needle aspirates, 85.0% (17/20) were diagnostic. Concordant histopathologic diagnosis was obtained in 100% (17/17) diagnostic fine needle aspirates. There were no postprocedural complications.

Postoperative lumbar fusion paraspinal desmoid tumor case report.

Desmoid tumors are rare soft tissue tumors with slow growth and high recurrence rates. They typically arise sporadically in the abdominal wall or retroperitoneum, with a few rare cases reported after trauma and surgery. Postoperative desmoid tumors in adults are very rare with only 7 reported cases involving the paraspinal location. This is the first reported case of a male patient with a postoperative paraspinal desmoid tumor.

Characterization of a Low-Profile, Flexible, and Acoustically Transparent Receive-Only MRI Coil Array for High Sensitivity MR-Guided Focused Ultrasound.

Magnetic resonance guided focused ultrasound (MRgFUS) is a non-invasive therapeutic modality for neurodegenerative diseases that employs real-time imaging and thermometry monitoring of targeted regions. MRI is used in guidance of ultrasound treatment; however, the MR image quality in current clinical applications is poor when using the vendor built-in body coil. We present an 8-channel, ultra-thin, flexible, and acoustically transparent receive-only head coil design (FUS-Flex) to improve the signal-to-noise ratio (SNR) and thus the quality of MR images during MRgFUS procedures. Acoustic simulations/experiments exhibit transparency of the FUS-Flex coil as high as 97% at 650 kHz. Electromagnetic simulations show a SNR increase of 13× over the body coil. In vivo results show an increase of the SNR over the body coil by a factor of 7.3 with 2× acceleration (equivalent to 11× without acceleration) in the brain of a healthy volunteer, which agrees well with simulation. These preliminary results show that the use of a FUS-Flex coil in MRgFUS surgery can increase MR image quality, which could yield improved focal precision, real-time intraprocedural anatomical imaging, and real-time 3D thermometry mapping.

Cervical spine ligamentum flavum gaps: MR characterisation and implications for interlaminar epidural injection therapy.

BACKGROUND: Cervical epidural steroid injections are commonly performed to manage pain from cervical spine disease. Cadaveric studies have demonstrated incomplete ligamentum flavum fusion in the central interlaminar region with resultant midline gaps. We performed an MR-based characterization of cervical ligamentum flavum midline gaps to improve understanding of their prevalence and guide interventionalists in procedural planning. METHODS: Fifty patients were retrospectively reviewed following institutional review board approval. Axial T2-weighted spinecho sequences were used to evaluate ligamentum flavum integrity at the interlaminar spaces of C5-C6, C6-C7 and C7-T1. Interlaminar spaces were further subdivided into superior, middle, and inferior portions, yielding 150 interlaminar regions characterized from C5 to T1. Subsequently, a novel categorization of gap morphology was performed, highlighting gap morphology (anterior, posterior, full, or no gap). RESULTS: Full gaps of the ligamentum flavum, with direct epidural space exposure, were observed with variable prevalence at all three levels evaluated. The highest incidence of full ligamentum flavum gaps were observed at C7-T1, occurring in 71.4% of patients at both its middle and inferior portions. The inferior aspect of C5-C6 demonstrated the lowest observed rates of full ligamentum flavum gap (2%). CONCLUSIONS: Ligamentum flavum gaps occur in the lower cervical spine at high rates, with the highest prevalence of full thickness ligamentum flavum gaps at C7-T1. Interventionists must be aware of these important normal variants and evaluate preprocedural MRI to plan interventions.

Identification and surgical ligation of spinal CSF-venous fistula.

BACKGROUND: CSF-venous fistulas (CVF) may cause incapacitating positional headaches resulting from spontaneous intracranial hypotension/hypovolemia (SIH). Their etiology remains unknown, although unrecognized local trauma may precipitate SIH. In addition, they are diagnostically challenging despite various imaging tools available. Here, we present CVF identification using magnetic resonance myelography (MRM) and elaborate on their surgical management techniques. METHODS: Retrospective charts of confirmed and treated CVF patients with attention to their diagnostic imaging modalities and management techniques were further reviewed. RESULTS: Six cases were identified of which three are presented here. There were two females and one male patient. All had fistulas on the left side. Two were at T7-T8 while the third was at T9-T10 level. Two underwent hemilaminotomies at the T7-T8 while the third underwent a foraminotomy at T9 level to access the fistula site. All CVF were closed with a combination of an aneurysm clip and a silk tie. On follow-up, all had complete resolution of symptoms with no evidence of recurrence. CONCLUSION: Of the various imaging modalities available, MRM is particularly sensitive in localizing CVF spinal nerve level and their laterality. In addition, the technique of aneurysm clip ligation and placement of a silk tie is curative for these lesions.