Subaxial lateral mass prosthesis for posterior reconstruction of cervical spine

Purpose: To obtain the relevant morphometry of the lateral mass of the subaxial cervical spine (C3-C7) and to design a series of lateral mass prostheses for the posterior reconstruction of the stability of cervical spine. Methods: The computed tomography (CT) scans of healthy volunteers were obtained. RadiAnt DICOM Viewer software (Version 2020.1, Medixant, Poland) was used to measure the parameters of lateral mass, such as height, anteroposterior dimension (APD), mediolateral dimension (MLD) and facet joint angle. According to the parameters, a series of cervical lateral mass prostheses were designed. Cadaver experiment was conducted to demonstrate its feasibility. Results: 23 volunteers with an average age of 30.1 ± 7.1 years were enrolled in this study. The height of lateral mass is 14.1 mm averagely. Facet joint angle, APD and MLD of lateral mass averaged 40.1 degrees, 11.2 mm and 12.18 mm, respectively. With these key data, a lateral mass prosthesis consists of a bone grafting column and a posterior fixation plate was designed. The column has a 4.0 mm radius, 41 degrees surface angle and adjustable height of 13, 15, or 17 mm. In the cadaver experiment, the grafting column could function as a supporting structure between adjacent facets, and it would not violate exiting nerve root (NR) or vertebral artery (VA). Conclusion: This study provided detailed morphology of the lateral mass of subaxial cervical spine. A series of subaxial cervical lateral mass prostheses were designed awaiting further clinical application.

HISTORY OF EVOLUTION OF POSTERO-LATERAL APPROACHES TO THE THORACIC SPINE: FROM CURE OF POTT’S DISEASE TO EPIDURAL TUMOR RESECTION

Since the end of the nineteenth century, the wide dissemination of Pott’s disease has ignited debates about which should be the ideal route to perform ventrolateral decompression of the dorsal rachis in case of paraplegia due to spinal cord compression in tuberculosis spondylitis. It was immediately clear that the optimal approach should be the one minimizing the surgical manipulation on both neural and extra-neural structures, while optimizing the exposure and surgical maneuverability on the target area. The first attempt was reported by Victor Auguste Menard in 1894, who described, for the first time, a completely different route from traditional laminectomy, called costotransversectomy. The technique was conceived to drain tubercular paravertebral abscesses causing paraplegia without manipulating the spinal cord. Over the following decades many other routes have been described all over the world, thus demonstrating the wide interest on the topic. Surgical development has been marked by the new technical achievements and by instrumental/technological advancements, until the advent of portal surgery and endoscopy-assisted techniques. Authors retraced the milestones of this history up to the present days, through a systematic review on the topic.

Microsurgical Anatomy of the Hypoglossal Nerve in the Lateral Approaches to the Craniovertebral Junction: A Study on Fresh Non-Formalin-Fixed Human Specimens

The aim of this anatomical study is to describe the anatomy of the hypoglossal nerve (HN) from its origin to the extracranial portion as it appears by performing a combined posterolateral and anterolateral approach to the craniovertebral junction (CVJ). Twelve fresh, non-formalin-fixed adult cadaveric heads (24 sides) were analyzed for the simulation of the combined lateral approach to the CVJ. The HN is divided into three main parts: cisternal, intracanalicular, and extracranial The anatomical relationships between the HN and other nerves, muscles, arteries and veins were carefully recorded, and some measurements were made between the HN and related structures. Thus, various landmarks were determined for the easy identification of the HN. Understanding the detailed anatomy of the HN and its relationships with the surrounding structures is crucial to prevent some complications during CVJ surgery.

Decompression of the Greater Occipital Nerve for Occipital Neuralgia and Chronic Occipital Headache Caused by Entrapment of the Greater Occipital Nerve

Background Chronic entrapment of the greater occipital nerve (GON) can not only manifest in typical stabbing pain of occipital neuralgia (ON) but also lead to continuous ache and pressure-like pain in the occipital and temporal areas. However, the effect of GON decompression on these symptoms has yet to be established. We report the follow-up results of GON decompression in typical cases of ON and chronic occipital headache due to GON entrapment (COHGONE). Methods A 1-year follow-up study of GON decompression was conducted on 11 patients with typical ON and 39 COHGONE patients with GON entrapment. The degree of pain reduction was analyzed using the numerical rating scale-11 (NRS-11) score and percent pain relief before and 1 year after surgery. A success was defined by at least a 50% reduction in pain measured via NRS-11 during the 12-month follow-up. To assess the degree of subjective satisfaction, a 10-point Likert scale was used. Postoperative outcome was also evaluated using the Barrow Neurological Institute (BNI) pain intensity score. The difference in GON decompression between the patients with typical ON and those with COHGONE was studied. Results GON decompression was successful in 43 of 50 patients (86.0%) and percent pain relief was 72.99 ± 25.53. Subjective improvement based on a 10-point Likert scale was 7.9 ± 2.42 and the BNI grade was 2.06 ± 1.04. It was effective in both the ON and COHGONE groups, but the success rate was higher in the ON group (90.9%) than in the COHGONE group (84.6%), showing statistically significant differences in the results based on average NRS-11 score, percent pain relief, subjective improvement, and BNI grades (p < 0.05, independent t-test). Conclusion GON decompression is effective in chronic occipital headache and in ON symptoms induced by GON entrapment.

Uniportal Full-Endoscopic versus Minimally Invasive Decompression for Lumbar Spinal Stenosis: A Meta-analysis

Background In this study, we systematically analyze the effectiveness of the uniportal full-endoscopic (UPFE) and minimally invasive (MIS) decompression for treatment of lumbar spinal stenosis patients. Methods We performed a systematic search in Medline, Embase, Europe PMC, PubMed, Web of Science, Cochrane databases, Chinese Biomedical Literature Database, China national knowledge infrastructure, and Wanfang Data databases for all relevant studies. All statistical analyses were performed using Review Manager version 5.3. Results A total of 9 articles with 522 patients in the UPFE group and 367 patients in the MIS group were included. The results of the meta-analysis showed that the UPFE group had significantly better results in hospital stay time (mean difference [MD]: –2.05; 95% confidence interval [CI]: –2.87 to –1.23), intraoperative blood loss (MD: –36.56; 95% CI: –54.57 to –18.56), and wound-related complications (MD: –36.56; 95%CI: –54.57 to –18.56) compared with the MIS group, whereas the postoperative clinical scores (MD: –0.66; 95%CI: –1.79 to 0.47; MD: –0.75; 95%CI: –1.86 to 0.36; and MD: –4.58; 95%CI: –16.80 to 7.63), satisfaction rate (odds ratio [OR] = 1.24; 95%CI: 0.70–2.20), operation time (MD: 30.31; 95%CI: –12.55 to 73.18), complication rates for dural injury (OR = 0.60; 95%CI: 0.29–1.26), epidural hematoma (OR = 0.60; 95%CI: 0.29–1.26), and postoperative transient dysesthesia and weakness (OR = 0.73; 95%CI: 0.36–1.51) showed no significant differences between the two groups. Conclusions The UPFE decompression is associated with shorter hospital stay time and lower intraoperative blood loss and wound-related complications compared with MIS decompression for treatment of lumbar spinal stenosis patients. The postoperative clinical scores, satisfaction rate, operation time, complication rates for dural injury, epidural hematoma, and postoperative transient dysesthesia and weakness did not differ significantly between two groups.

Treatment of Unique Bilateral Distal Fusiform Superior Cerebellar Artery Aneurysms with Mini-Flow Diverter Device Implantation: Case Report

Currently, surgical revascularization procedures using intracranial–intracranial (IC-IC) or extracranial–intracranial (EC-IC) bypass and distal clipping or trapping are the valid and rescue treatment modality for extremely rare unilateral distal fusiform superior cerebellar artery (SCA) aneurysms. Yet, in case of bilateral fusiform SCA aneurysms, surgical therapy reaches its limit. Mini-flow diverter devices (FDDs) have only recently become available for treating fusiform aneurysms of such small vessels. We report the unique case of bilateral distal fusiform SCA aneurysms in a 43-year-old man with subarachnoid hemorrhage (Fisher grade IV and World Federation of Neurosurgical Societies [WFNS] grade II) treated with endovascular implantation of bilateral mini-FDDs with excellent outcome and no radiographic signs of infarction. Yet, occlusion of one of the FDDs was found in the follow-up, which again shows the eminent danger of occlusion in case of an implantation of FDDs in such small-caliber vessels, which leaves the discussion about the optimal therapy method open.

Intraoperative Spinal Angiography during Microsurgical Occlusion of Spinal Dural Arteriovenous Fistula within the Hybrid Operation Room

Background Spinal dural arteriovenous fistula (SDAVF) is a rare cause of progressive myelopathy in predominantly middle-aged men. Treatment modalities include surgical obliteration and endovascular embolization. In surgically treated cases, failure of obliteration is reported in up to 5%. The aim of this technical note is to present a safe procedure with complete SDAVF occlusion, verified by intraoperative digital subtraction angiography (DSA). Methods We describe four patients with progressive leg weakness who underwent surgical obliteration of SDAVF with spinal intraoperative DSA in the prone position after cannulation of the popliteal artery. All surgeries took place in our hybrid operating room (OR) and were accompanied by electrophysiologic monitoring. Surgeries and cannulation of the popliteal artery were performed in the prone position. Ultrasound was used to guide the popliteal artery puncture. A 5-Fr sheath was inserted and the fistula was displayed using a 5-Fr spinal catheter. Spinal intraoperative DSA was performed prior to and after temporary clipping of the fistula point as well after the final SDAVF occlusion. Results The main feeder of the SDAVF fistula in the first patient arose from the right T11 segmental artery, which also supplied the artery of Adamkiewicz. The second patient initially underwent endovascular treatment and deteriorated 5 months later due to recanalization of the SDAVF via a small branch of the T12 segmental artery. The third and fourth cases were primarily scheduled for surgical occlusion. Access through the popliteal artery for spinal intraoperative DSA proved to be beneficial and safe in the hybrid OR setting, allowing the sheath to be left in place during the procedure. During exposure and after temporary and permanent occlusion of the fistulous point, intraoperative indocyanine green (ICG) video angiography was also performed. In one case, the addition of intraoperative DSA showed failure of fistula occlusion, which was not visible with ICG angiography, leading to repositioning of the clip. Complete fistula occlusion was documented in all cases. Conclusion Spinal intraoperative DSA in the prone position is a feasible and safe intervention for rapid localization and confirmation of surgical SDAVF occlusion.

Association between Brachycephaly, Chiari Malformation, and Basilar Invagination

Background There is evidence that Chiari malformation (CM) and basilar invagination (BI) are largely due to disproportion between the content and volume of the posterior fossa. A recent study identified an increased association between brachycephaly and BI. In several types of craniosynostosis, the posterior fossa volume is smaller than normal, and this is more pronounced in coronal synostosis. The aim of this study is to evaluate the association between CM and BI. Methods The cephalic index (CI) measured on magnetic resonance imaging (MRI) from a sample of patients with craniocervical malformation was compared with that of normal subjects. Results The average CI in the craniovertebral junction malformation (CVJM) group was significantly higher in BI patients than in normal subjects. The BI patients also had the highest CI among the whole sample of patients (p = 0.009). Conclusions In this study, BI patients had the highest CI among patients with CVJM and a significantly higher CI than those in the control group. Our data confirm the association between BI and brachycephaly.