Microendoscopic Tailored Spine Decompression as a Less-Invasive, Stability-Preserving Surgical Option to Instrumented Correction in Complex Spine Deformities: A Preliminary Multicenter Experience.

OBJECTIVES: The aim of this study was to explore the effectiveness of a less-invasive posterior spine decompression in complex deformities. We studied the potential advantages of the microendoscopic approach, supplemented by the piezoelectric technique, to decompress both sides of the vertebral canal from a one-sided approach to preserve spine stability, ensuring adequate neural decompression. METHODS: A series of 32 patients who underwent a tailored stability-preserving microendoscopic decompression for lumbar spine degenerative disease was retrospectively analyzed. The patients underwent selective bilateral decompression via a monolateral approach, without the skeletonization of the opposite side. For omo- and the contralateral decompression, we used a microscopic endoscopy-assisted approach, with the assistance of piezosurgery, to work safely near the exposed dura mater. Piezoelectric osteotomy is extremely effective in bone removal while sparing soft tissues. RESULTS: In all patients, adequate decompression was achieved with a high rate of spine stability preservation. The approach was essential in minimizing the opening, therefore reducing the risk of spine instability. Piezoelectric osteotomy was useful to safely perform the undercutting of the base of the spinous process for better contralateral vision and decompression without damaging the exposed dura. In all patients, a various degree of neurologic improvement was observed, with no immediate spine decompensation. CONCLUSIONS: In selected cases, the tailored microendoscopic monolateral approach for bilateral spine decompression with the assistance of piezosurgery is adequate and safe and shows excellent results in terms of spine decompression and stability preservation.

The High Cervical Anterolateral Retropharyngeal Approach.

The first high cervical anterolateral retropharyngeal (HCALR) approach was reported by Stevenson et al. for a clivus chordoma in 1966. Anterior approaches to the spine have often been developed in response to problems presented by tuberculous spondylitis. This approach is indicated in anterior high cervical spine cases such as tumour resection, abscess drainage, atlantoaxial subluxation; decompression and stabilization. To our knowledge, only 21 papers in the literature have mentioned this approach. Its main advantage over posterior approaches is easy positioning and minimal need for soft tissue dissection. The HCALR approach provides wide exposure (of the anterior upper cervical spine, lower clivus and brainstem region) and feasibility for instrumentation. The limited space in which important neurovascular and visceral structures course and overlap contributes to the complexity of the anatomy. Navigating this intricate anatomy is essential for the safety of this approach and has been a drawback for utilization of the retropharyngeal corridor. This approach is one of the safest and most effective methods available to access the craniocervical junction. The benefits clearly outweigh the risks and complications.

The Far Lateral Approach to the Craniovertebral Junction: An Update.

INTRODUCTION: Since 1972, when Hammon first described the far lateral approach (FLA) for treatment of vertebral artery aneurysms, it has undergone numerous modifications, including drilling of the occipital condyle, removal of the laminas of upper cervical vertebrae and so on. Also, the range of indications has increased exponentially. OBJECTIVE: In this paper we discuss state-of-the-art advances in the FLA, such as promising minimally invasive variants where an endoscope is used, and many others. METHODS: We reviewed all articles touching upon the FLA in the modern era (from the year 2000 onward) and selected those that presented a significant contribution to the development of the relevant approach. The database used was PubMed. RESULTS AND CONCLUSION: We found several new caveats not mentioned in other reviews or book chapters. The FLA is an ever-changing field of battle where the common and ultimate goals are to minimize the risk of injuring the major vessel in the region-the vertebral artery-and to provide such an angle of attack upon the tumours in the anterior and anterolateral foramen magnum that it is feasible to ensure gross total resection. This paper is an update on the knowledge about this approach, which we feel is necessary.

Extreme Lateral Approach to the Craniovertebral Junction: An Update.

INTRODUCTION: The term 'extreme lateral approach' (ELA) was first introduced by Sen and Sekhar relatively recently (in 1990). Its definition varies and remains controversial, but it generally entails more aggressive bony removal than the far lateral approach (FLA). GOAL: In this paper we review the relevant literature and weigh up the advantages and disadvantages of this approach. We propose methods to manage the complications resulting from the more invasive character of the ELA. Some modern trends regarding how to definitely distinguish the ELA from the FLA are also presented. METHODS: Using the PubMed database, literature was collected on the relevant topics and subsequently reviewed. All up-to-date tips and tricks were carefully gathered, and current morbidity and mortality rates were obtained, as well as further perspectives. RESULTS AND CONCLUSION: The morbidity associated with the ELA remains higher than that associated with the FLA, but the mortality nowadays is comparable. The ELA undoubtedly is a challenging procedure requiring deep insight into the relevant anatomy and its normal variants.

Insights into the Past and Future of Atlantoaxial Stabilization Techniques.

Over the past century, atlantoaxial stabilization techniques have improved considerably. To our knowledge there has been a scarcity of articles published that focus specifically on the history of atlantoaxial stabilization. Examining the history of instrumentation allows us to evaluate the impact of early influences on current modern stabilization techniques. It also provides inspiration to further develop the techniques and prevents repetition of mistakes. This paper reviews the evolution of C1-C2 instrumentation techniques over time and provides insights into the future of these practices.We did an extensive literature search in PubMed, Embase and Google Scholar, using the following search terms: 'medical history', 'atlantoaxial', 'C1/C2', 'stabilization', 'instrumentation', 'fusion', 'arthrodesis', 'grafting', 'neuroimaging', 'biomechanical testing', 'anatomical considerations' and 'future'.Many different entry zones have been tested, as well as different constructs, from initial attempts with use of silk threads to use of hooks and rod-wire techniques, and handling of bone grafts, which eventually led to the development of the advanced screw-rod constructs that are currently in use. Much of this evolution is attributable to advancements in neuroimaging, a wide range of new materials available and an improvement in biomechanical understanding in relation to anatomical structures.