Full-endoscopic uniportal retropharyngeal odontoidectomy for anterior craniocervical infection.

BACKGROUND: Infections of the anterior craniocervical junction may require surgery. There are various techniques with individual advantages and disadvantages. This study evaluates the full-endoscopic uniportal technique via the anterior retropharyngeal approach for odontoidectomy, decompression, and debridement. MATERIAL AND METHODS: Three patients with an infection of the anterior craniocervical junction with retrodental involvement were operated on between 2014 and 2016 using the full-endoscopic uniportal technique. Posterior stabilization was also performed with the same procedure for all patients. RESULTS: The operation was technically satisfactory in all cases. No problems due to swelling of the pharyngeal soft tissue occurred. No other complications were observed. All patients had a satisfactory outcome with stable regression of the myelopathy symptoms and/or complete healing of the infection. The follow-up images showed sufficient decompression of bone and soft tissues in all cases. CONCLUSIONS: The full-endoscopic uniportal technique with an anterior retropharyngeal approach can be an adequate and minimally invasive surgical technique for odontoidectomy, decompression, and debridement in infections of the craniocervical junction and can reduce access-related problems. The transoral, transnasal, and retropharyngeal approaches have different surgical fields due to the access trajectories, which must be taken into consideration depending on the anatomy and pathology when selecting a suitable technique.

The full-endoscopic uniportal technique for decompression of the anterior craniocervical junction using the retropharyngeal approach: an anatomical feasibility study in human cadavers and review of the literature.

Objective: Acute or progressive myelopathy may necessitate direct anterior decompression of the craniocervical junction and odontoidectomy. Different techniques with individual advantages and disadvantages can be used. In addition to the gold standard-the transoral approach-there is also increasing experience with the endoscopic transnasal technique. Other alternative methods are also being developed to reduce technical and perioperative problems. The aim of this anatomical study was to investigate the feasibility of the full-endoscopic uniportal technique with a retropharyngeal approach for decompression of the craniocervical junction, taking into consideration the specific advantages and disadvantages compared with conventional methods and the currently available data in the literature. Methods: Five fresh adult cadavers were operated on. The endoscope used has a shaft cross-section of 6.9 × 5.9 mm and a 25° viewing angle. It contains an eccentric intraendoscopic working channel with a diameter of 4.1 mm. An anterior retropharyngeal approach was used. The anatomical structures of the anterior craniocervical junction were dissected and the bulbomedullary junction was decompressed. Results: The planned steps of the operation were performed in all cadavers. The retropharyngeal approach allowed the target region to be accessed easily. The anatomical structures of the anterior craniocervical junction could be identified and dissected. The bulbomedullary junction could be adequately decompressed. No resections of the anterior arch of the atlas were necessary in the odontoidectomy. Conclusions: Using the full-endoscopic uniportal technique with an anterior retropharyngeal approach, the craniocervical region can be adequately reached, dissected, and decompressed. This is a minimally invasive technique with the known advantages of an endoscopic procedure under continuous irrigation. The retropharyngeal approach allows direct, sterile access. The instruments are available for clinical use and have been established for years in other operations of the entire spine.

Operation of Soft or Calcified Thoracic Disc Herniations in the Full-Endoscopic Uniportal Extraforaminal Technique.

BACKGROUND: Surgery for thoracic disc herniation and stenosis is comparatively rare and often demanding. The goal is to achieve sufficient decompression without manipulating the spinal cord and to minimize surgical trauma and its consequences. Individual planning and various surgical techniques and approaches are required. The key factors for selecting the technique are anatomical location, consistency of the pathology, general condition of the patient, and the surgeon's experience. OBJECTIVES: The objective of the study was the evaluation of the technical implementation and outcomes of a full-endoscopic uniportal technique via the extraforaminal approach in patients with symptomatic soft or calcified disc herniation of the thoracic spine, taking specific advantages and disadvantages and literature into consideration. STUDY DESIGN: Retrospective study. SETTING: A center for spine surgery and pain medicine. METHODS: Between 2009 and 2015, decompression was performed on 26 patients with thoracic disc herniation or stenosis with radicular or myelopathic symptoms in a full-endoscopic uniportal technique with an extraforaminal approach. No patients underwent additional posterior stabilization. Imaging and clinical data were collected in follow-up examinations for 18 months. RESULTS: Sufficient decompression was achieved in the full-endoscopic uniportal technique in all cases. The individual selection of the respective approach made it possible to reach the target area without manipulating the spinal cord. One patient experienced deterioration of a myelopathy. No other serious complications were observed. All patients, except one, experienced regression or improvement of symptoms. No evidence of increasing instability was found in imaging. LIMITATIONS: This is a retrospective study. The limited number of cases must be considered. CONCLUSIONS: The full-endoscopic uniportal technique with an extraforaminal approach was found to be a sufficient and minimally invasive method with the known advantages of an endoscopic procedure under continuous irrigation for monosegmental disc herniations. The inclusion criteria must be taken into consideration. If they are not met, an alternative full-endoscopic approach (interlaminar, transthoracic retropleural) or decompression in a conventional method must be selected. Additional stabilization does not appear to be necessary due to the low level of trauma. KEY WORDS: Extraforaminal approach, thoracic disc herniation, giant disc herniation, Full-endoscopic, minimally invasive, thoracic spine.

Full-endoscopic uniportal decompression in disc herniations and stenosis of the thoracic spine using the interlaminar, extraforaminal, or transthoracic retropleural approach.

OBJECTIVE Surgery for thoracic disc herniation and spinal canal stenosis is comparatively rare and often challenging. Individual planning and various surgical techniques and approaches are required. The key factors for selecting the technique and approach are anatomical location, consistency of the pathology, general condition of the patient, and the surgeon's experience. The objective of the study was to evaluate the technical implementation and outcomes of a full-endoscopic uniportal technique via the interlaminar, extraforaminal, or transthoracic retropleural approach in patients with symptomatic disc herniation and stenosis of the thoracic spine, taking specific advantages and disadvantages and literature into consideration. METHODS Between 2009 and 2015, decompression was performed in 55 patients with thoracic disc herniation or stenosis using a full-endoscopic uniportal technique via an interlaminar, extraforaminal, or transthoracic retropleural approach. Imaging and clinical data were collected during follow-up examinations for 18 months. RESULTS Sufficient decompression was achieved in the full-endoscopic uniportal technique. One patient required revision due to secondary bleeding, and another exhibited persistent deterioration on myelopathy. No other serious complications were observed. All but one patient experienced regression or improvement of their symptoms. CONCLUSIONS The full-endoscopic uniportal technique with an interlaminar, extraforaminal, or transthoracic retropleural approach was found to be a sufficient and minimally invasive method. To cover the entire range of thoracic disc herniations and stenosis within the criteria named, all full-endoscopic approaches are required.

Surgical treatment of cervical subaxial intraspinal extradural cysts using a full-endoscopic uniportal posterior approach.

PURPOSE: Symptomatic intraspinal extradural cysts of the cervical subaxial spine are rare, but usually require surgery. Conventional posterior decompression is the gold standard. However, there is increasing experience with endoscopic surgical techniques. The purpose of the study is to evaluate the technical implementation and outcomes of a full-endoscopic uniportal technique via the posterior approach in patients with symptomatic intraspinal extradural cysts of the cervical subaxial spine. METHODS: Seven consecutive patients with a subaxial location of symptomatic intraspinal extradural cysts were decompressed in a full-endoscopic uniportal technique via the posterior approach between 2009 and 2015. Imaging and clinical data were collected in follow-up examinations for 18 months. RESULTS: In all cases, the cyst was completely removed and adequate decompression was achieved using the full-endoscopic uniportal technique. One patient developed a dural leak that was sutured and covered intraoperatively. No other complications requiring treatment were observed. All patients had a good clinical outcome with stable regression of the radicular and central nerve pain or neurological deficits. The imaging follow-up showed sufficient decompression in all cases. No evidence was found of increasing instability during the follow-up period. CONCLUSION: The full-endoscopic uniportal operation with a posterior approach allows the resection of the cyst and can minimize trauma and destabilization and has technical benefits and a low complication rate. It is an alternative surgical method that can offer advantages and is considered by the authors to be the surgical technique of choice for cervical subaxial intraspinal extradural cysts.

Decompression of the anterior thoracic spinal canal using a novel full-endoscopic uniportal transthoracic retropleural technique-an anatomical feasibility study in human cadavers.

Surgery for thoracic disc herniation and spinal stenosis is comparatively rare and often demanding. The goal is to achieve sufficient decompression without manipulating the spinal cord. Individual planning and various surgical techniques and approaches are required. This anatomical study examines the feasibility of a novel full-endoscopic uniportal technique with a transthoracic retropleural approach for decompression of the anterior thoracic spinal canal. Operations were performed on three fresh adult cadavers. The endoscope used, from RIWOspine, Germany, has a shaft cross-section of 6.9 × 5.9 mm and a 25° view angle. It contains an eccentric intraendoscopic working channel with a diameter of 4.1 mm. A transthoracic retropleural approach was used. The anatomical structures were dissected and the anterior thoracic epidural space was decompressed. The planned steps of the operation were performed on all cadavers. The transthoracic retropleural approach allowed the target region to be accessed easily. The anatomical structures could be identified and dissected. The anterior thoracic epidural space could be decompressed sufficiently. Using the uniportal full-endoscopic operation technique with a transthoracic retropleural approach, the anterior thoracic epidural space can be adequately reached. This is a minimally invasive method with the known advantages of an endoscopic technique under continuous irrigation. The retropleural approach allows direct access. The instruments are available for clinical use and have been established for years in other operations on the entire spine. Clin. Anat. 31:716-723, 2018. © 2018 Wiley Periodicals, Inc.

Full-endoscopic Uniportal Odontoidectomy and Decompression of the Anterior Cervicomedullary Junction Using the Retropharyngeal Approach.

STUDY DESIGN: A study of a series of consecutive full-endoscopic uniportal decompressions of the anterior craniocervical junction with retropharyngeal approach. OBJECTIVE: The aim of this study was to evaluate the direct anterior decompression of the craniocervical junction in patients with bulbomedullary compression using a full-endoscopic uniportal technique via an anterolateral retropharyngeal approach. SUMMARY OF BACKGROUND DATA: Acute or progressive myelopathy may necessitate direct anterior decompression of the craniocervical junction and odontoidectomy. Different techniques with individual advantages and disadvantages can be used. In addition to the gold standard - the transoral approach - there is increasing experience with the endoscopic transnasal technique. Other alternative procedures are also being developed. METHODS: Between 2013 and 2016, eight patients with basilar impression, retrodental pannus, or retrodental infection were operated in the full-endoscopic uniportal technique with a retropharyngeal approach. Anterior decompression of the bulbomedullary junction with odontoidectomy was performed. All patients additionally underwent posterior stabilization. Imaging and clinical data were collected in follow-up examinations for 1 year. RESULTS: The bulbomedullary junction was adequately decompressed. No problems due to swelling of pharyngeal soft tissue occurred. One patient required revision due to secondary bleeding. No other complications were observed. All patients had a good clinical outcome with stable regression of the myelopathy symptoms and/or healing of the infection. The imaging follow-up showed sufficient decompression of bone and soft tissue in all cases. No evidence was found of increasing instability or failure of posterior fusion. CONCLUSION: In the operated patients, the full-endoscopic uniportal surgical technique with anterior retropharyngeal approach was found to be a sufficient and minimally invasive method with the known advantages of an endoscopic procedure under continuous irrigation. It should not be viewed only as competition for other surgical techniques - due to its individual technical parameters, it can also be considered to be an alternative or complementary procedure. LEVEL OF EVIDENCE: 4.

A New Electromagnetic Navigation System for Pedicle Screws Placement: A Human Cadaver Study at the Lumbar Spine.

INTRODUCTION: Technical developments for improving the safety and accuracy of pedicle screw placement play an increasingly important role in spine surgery. In addition to the standard techniques of free-hand placement and fluoroscopic navigation, the rate of complications is reduced by 3D fluoroscopy, cone-beam CT, intraoperative CT/MRI, and various other navigation techniques. Another important aspect that should be emphasized is the reduction of intraoperative radiation exposure for personnel and patient. The aim of this study was to investigate the accuracy of a new navigation system for the spine based on an electromagnetic field. MATERIAL AND METHOD: Twenty pedicle screws were placed in the lumbar spine of human cadavers using EMF navigation. Navigation was based on data from a preoperative thin-slice CT scan. The cadavers were positioned on a special field generator and the system was matched using a patient tracker on the spinous process. Navigation was conducted using especially developed instruments that can be tracked in the electromagnetic field. Another thin-slice CT scan was made postoperatively to assess the result. The evaluation included the position of the screws in the direction of trajectory and any injury to the surrounding cortical bone. The results were classified in 5 groups: grade 1: ideal screw position in the center of the pedicle with no cortical bone injury; grade 2: acceptable screw position, cortical bone injury with cortical penetration ≤ 2 mm; grade 3: cortical bone injury with cortical penetration 2,1-4 mm, grad 4: cortical bone injury with cortical penetration 4,1-6 mm, grade 5: cortical bone injury with cortical penetration >6 mm. RESULTS: The initial evaluation of the system showed good accuracy for the lumbar spine (65% grade 1, 20% grade 2, 15% grade 3, 0% grade 4, 0% grade 5). A comparison of the initial results with other navigation techniques in literature (CT navigation, 2D fluoroscopic navigation) shows that the accuracy of this system is comparable. CONCLUSION: EMF navigation offers a high accuracy in Pedicle screw placement with additional advantages compared to other techniques. The short set-up time and easy handling of EMF navigation should be emphasized. Additional advantages are the absence of intraoperative radiation exposure for the operator and surgical team in the current set-up and the operator's free mobility without interfering with navigation. Further studies with navigation at higher levels of the spine, larger numbers of cases and studies with control group are planned.

Navigation of pedicle screws in the thoracic spine with a new electromagnetic navigation system: a human cadaver study.

INTRODUCTION: Posterior stabilization of the spine is a standard procedure in spinal surgery. In addition to the standard techniques, several new techniques have been developed. The objective of this cadaveric study was to examine the accuracy of a new electromagnetic navigation system for instrumentation of pedicle screws in the spine. MATERIAL AND METHOD: Forty-eight pedicle screws were inserted in the thoracic spine of human cadavers using EMF navigation and instruments developed especially for electromagnetic navigation. The screw position was assessed postoperatively by a CT scan. RESULTS: The screws were classified into 3 groups: grade 1 = ideal position; grade 2 = cortical penetration <2 mm; grade 3 = cortical penetration ≥2 mm. The initial evaluation of the system showed satisfied positioning for the thoracic spine; 37 of 48 screws (77.1%, 95% confidence interval [62.7%, 88%]) were classified as group 1 or 2. DISCUSSION: The screw placement was satisfactory. The initial results show that there is room for improvement with some changes needed. The ease of use and short setup times should be pointed out. Instrumentation is achieved without restricting the operator's mobility during navigation. CONCLUSION: The results indicate a good placement technique for pedicle screws. Big advantages are the easy handling of the system.

Bilateral spinal decompression of lumbar central stenosis with the full-endoscopic interlaminar versus microsurgical laminotomy technique: a prospective, randomized, controlled study.

BACKGROUND: Extensive decompression with laminectomy, where appropriate, is often still described as the method of choice when operating on degenerative lumbar spinal stenosis. Nonetheless, tissue-sparing procedures are becoming more common. Endoscopic techniques have become the standard in many areas because of the surgical advantages they offer and the benefits for rehabilitation. One key issue when operating on the spine was the development of instruments to provide sufficient bone resection under continuous visual control. This was achieved by using endoscopes for operations carried out in cases of spinal canal stenosis. OBJECTIVE: This study of patients with degenerative lumbar central spinal stenosis compares the results of spinal decompression using the full-endoscopic interlaminar technique (FI) with a conventional microsurgical laminotomy technique (MI). STUDY DESIGN: Prospective, randomized, controlled study. SETTINGS: 135 patients with microsurgical or full-endoscopic decompression were followed up for 2 years. Alongside general and specific parameters, the following measuring instruments were also used for the investigation: Visual Analog Scale (VAS), German version of the North American Spine Society Instrument (NASS), Oswestry Low-Back-Pain-Disability Questionnaire (ODI). RESULTS: Postoperatively 72 % of the patients no longer had leg pain or the pain was almost completely reduced and 21.2 % experienced occasional pain. The clinical results were the same in both groups. The rate of complications and revisions was significantly reduced in the FI Group. The full-endoscopic techniques brought advantages in the following areas: operation, complications, traumatization, rehabilitation. LIMITATIONS: Lack of placebo control group. CONCLUSIONS: The recorded results demonstrate that the full-endoscopic interlaminar bilateral decompression adopting a unilateral approach provides an adequate and safe supplement and alternative to the conventional microsurgical bilateral laminotomy technique when the indication criteria are fulfilled. At the same time, it offers the advantages of a minimally invasive intervention.