History of Endoscopic Spine Surgery in India

Endoscopic spine surgeries provide distinct advantages and is therefore a viable alternative to open or microscopic techniques. Indian surgeons have shown their expertise from craniovertebral junction to lumbosacral spine with these techniques. Many novel approaches like endoscopic transcervical, partial corpectomy, and others have been designed, and many technological innovations for these surgeries have been made. With different training programs attracting both native and international surgeons, the future of endoscopic spine surgery is bright.

Percutaneous CT-Guided Biopsy of the Craniovertebral Junction: Safety, Diagnostic Yield, and Technical Notes

The craniovertebral junction defined as the occiput, the atlas, and the axis is a complex bony region that contains vital neural and vascular structures. We report the experience of a single academic institution regarding CT-guided biopsy of this skeletal region. We reviewed all of the CT-guided biopsies performed in our department, completed in the craniovertebral junction. We collected data in regard to biopsy procedures, patients’ vital statistics, and histopathological diagnosis. In total, 16 patients (8M and 8F; mean age 52; range 16–86 years old) were included in this series. In eight patients, the lesions were located in the atlas vertebra (8/16—50%), in six patients in the axis (37.5%), and in two patients in the occiput (12.5%). No complications were observed during or after the procedures. All of the procedures were technically successful. The biopsy was diagnostic in 13/16 patients (81.3%): four metastatic lesions (25%—three breast and one prostate cancers), four multiple myeloma bone lesions (25%), three aneurismal bone cysts (18.8%), one aggressive hemangioma (6.3%), and one pseudogout (6.3%). Moreover, in two-thirds (66.6%) of non-diagnostic histological reports, malignancies were excluded. CT-guided percutaneous biopsy is a safe tool and allows obtaining a histological diagnosis, in most cases, even in the most delicate site of the human skeleton—the craniovertebral junction.

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.

Vertebral Artery Variations at the Craniovertebral Junction in “Sandwich” Atlantoaxial Dislocation Patients

Objective: To summarize the vertebral artery (VA) pattern of 96 “sandwich” atlantoaxial dislocation (AAD) patients and to describe the strategies of reducing the injury of VA during surgery.Methods: From 2009 to 2020, we retrospectively reviewed the 3-dimensional computed tomography angiography data of 96 AAD patients combined with atlas occipitalization and C2–3 fusion, which were diagnosed as “sandwich” AAD and 96 patients as control group patients who were without atlas occipitalization, C2–3 fusion and any other cervical bone deformity at our institution. The variations of each side of VA were described in 3 different parts (C0–1, C1–2, and C2–3) according to the characteristics of the 3-part pathological structures in “sandwich” subgroup.Results: One hundred ninety-two sides of VAs in every group of patients were analyzed and every VA was described separately at 3 different level regions. There were different variations in these 3 different regions: 4 variations in the upper fusion region, 5 variations in the sandwiched region, and 6 variations in the lower fusion region in sandwich AAD patients. And the rate of VA deformity in sandwich AAD patients was much higher and more types of VA variations existed.Conclusion: In “sandwich” AAD patients, deformities of vertebral arteries in craniovertebral junction are more common, and the same VA may have deformities at different levels that severely affect surgical procedures. Therefore, preoperative imaging examination of VA for “sandwich” AAD patients is vital of guiding surgeons to avoid injury of VA during surgery.

Anatomical variations of posterior inferior cerebellar artery (PICA) on digital subtraction angiography (DSA)

Introduction: The posterior inferior cerebellar artery (PICA) often exhibits anatomical variations at the craniovertebral junction. Few studies investigated variations of the posterior inferior cerebellar artery, and the prevalence of other variations has not been reported. The study aimed to identify variations of the posterior inferior cerebral artery using cerebral Digital Subtraction Angiography (DSA). Method: 50 patients underwent 64-slice cerebral Digital Subtraction Angiography. Four types of variations were observed. Results: Out of a total of 50 patients, 23 (46%) were males and 27 (54%) females (all age groups). Our study has shown the utility of the 2 sequences - fluoroscopy and cine. All 2 sequences have their significance in evaluating anatomical variations in PICA. Only 20% of the 50 patients had all the posterior inferior cerebellar artery without anatomical variations. Anatomic variations commonly involve the distal segment of the vertebral artery (VA). Most of them are seen arising from the C1, C2, and both C1 and C2 origins. Anatomic variations involve arising from the C1 origin in 9 patients, C2 origin in 11 patients, C1 & C2 origin in 8 patients, and other variations observed in 12 patients. Conclusion: Variations of the posterior inferior cerebellar artery can be easily evaluated by cerebral Digital Subtraction Angiography (CDSA). Recognizing and reporting them at cerebral CDSA may be clinically important. Surgeons should be mindful of this variation during operations.

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.

Endonasal Endoscopic and Transoral Approaches to the Craniovertebral Junction and the Clival Region

Introduction: The transoral approach was first described by Kanavel in 1917 to treat injuries of the craniospinal junction. In 2002, Frempong-Boaudu reported 7 adults who underwent endoscopically assisted transoral surgery, this was the first report that endoscope was used in an assisted manner for transoral surgery. In 2005, Kassam published the first report of an EEA being used to perform an odontoidectomy. Method: A descriptive, retrospective and linear study was carried out in 16 patients who underwent surgery using the microsurgical and endoscopic transoral and Extended Endoscopic Endonasal approach in the period from January 2004 to May 2021. Results: The average age of the patients was 45 years and there was a predominance of the male sex (10) with the female one (6). The tumoral pathology (9), 6 cases with histological diagnosis of clivus cordroma and 1 patient with chondrosarcoma, two cases with Meningioma and cholesterol granuloma of clival localization, achieving gross total resection in 2 of them and in the rest subtotal resection, all improved neurological symptoms. Complications, partial dehiscence of the velopalatine surgical wound 1 case, 1 lesion of the left vertebral artery and 1 case decompensated Diabetes Mellitus and hemoneumothorax during stay in the ICU, which death 7 days after surgery and 1 CSF fistula. Conclusions: Both, the transoral and endonasal endoscopic approaches have their precise indications in each particular case, having their indications well defined. To achieve this, we must have neuroimaging studies and be able to correctly define the selection of the surgical approach.

Kraniovertebral Bileşke Kemiklerinin Morfometrik Özellikleri

Introduction: The craniovertebral junction comprises the occipital bone, atlas, axis and supporting ligaments. Surgical interventions for treatment of instability, require knowledge of morphometric properties of this area. Therefore, the aim of the present study was to evaluate adult dried human skulls to analyze morphometric features of the bones that joined the craniovertebral junction. Materials and Methods: Morphometric analysis was performed on dry bones which found in the excavations. 9 occipital bone, 18 atlas and 16 axis were measured. Differences between measurements were determined using t-tests and were considered significant at p<0.05. Results: The distance between both tips of the transverse processes (p<0.001), the distance between both outermost edges of the transverse foramen (p=0.011), the distance between both innermost edges of the transverse foramen (p=0.013), the maximum transverse diamater of the vertebral canal (p=0.014), the maximum anteroposterior diameter of the vertebral canal (p=0.014) and the width of the inferior articular facet (left p<0.001 and right p=0.005) were found significantly shorter in females atlases. The width of the dens axis (p<0.001), the height of the corpus axis (p=0.034), the distance from lateral most edge of the transvers process to midline (left p=0.049), the length of the inferior articular facet (left p=0.004, right p=0.005), the width of the superior articular facet (right p=0.007) were found significantly shorter in females axises. Conclusion: Morphometric analysis is very important in the development and improvement of surgical techniques. In this context, the results of our study can contribute to developments in this area. Keywords: Atlas, axis, occipital bone, craniovertebral junction