Anterocentral Portal in Ankle Arthroscopy.

BACKGROUND: The anterocentral portal is not a standard portal in anterior ankle arthroscopy due to its proximity to the anterior neurovascular bundle. However, it provides certain advantages, including a wide field of vision, and portal changes become redundant. The purpose of this study was to evaluate the neurovascular complications after anterior ankle arthroscopy using the anterocentral portal. METHODS: We retrospectively identified patients who had undergone anterior ankle arthroscopy with an anterocentral portal at our institution from 2013 to 2018. Medical record data were reviewed and patients were invited for clinical follow-up, where a clinical examination, quantitative sensory testing for the deep peroneal nerve, and ultrasonography of the structures at risk were performed. A total of 101 patients (105 arthroscopies) were identified and evaluated at a mean follow-up of 31.5 ± 17.7 months. RESULTS: Leading indications to surgery were heterogeneous and included anterior impingement (48.6%), osteochondral lesions of the talus (24.8%), chronic ankle instability (14.3%), and fractures (8.6%). The overall complication rate was 7.6%, and no major complications were observed. In 1.9% (2/105) of the cases, the complications were associated with the anterocentral portal and included injury to the medial branch of the superficial nerve (1/105) and to the deep peroneal nerve (1/105). Injury to the deep peroneal nerve was associated with a loss of detection and nociception. There were no injuries to the anterior tibial artery. In 41.9% (44/105) of the cases, only 1 working portal was used in addition to the anterocentral portal, and in 19% (20/105) the anterolateral portal could be avoided. Ultrasonography confirmed the integrity of the deep peroneal nerve, the medial branch of the superficial peroneal nerve, and the anterior tibial artery in all patients. Patients with nerve injuries associated with the anterocentral portal showed no signs of neuroma or pseudoaneurysm. CONCLUSION: Using a standardized technique, the anterocentral portal in ankle arthroscopy is safe with a low number of neurovascular injuries and can be recommended as a standard portal. The anterolateral portal remains associated with a high number of injuries to the superficial peroneal nerve. LEVEL OF EVIDENCE: Level III, retrospective cohort study.

The Learning Curve of Subaxial Cervical Pedicle Screw Placement: How Can We Avoid Neurovascular Complications in the Initial Period?

BACKGROUND: Despite the biomechanical benefits of subaxial cervical pedicle screw (CPS) placement, possible neurovascular complications, including vertebral artery and nerve root injury, are of great concern. We have demonstrated many times the safety and efficacy of CPS deployments, even when using freehand technology. OBJECTIVE: To analyze the learning curve of CPS placement to determine the number of cases necessary for assuring safe CPS placement and to identify a reasonable accuracy rate. METHODS: From March 2012 to August 2018, a single surgeon performed posterior cervical fusion surgery using CPS placement on 162 consecutive patients. We classified whole surgical periods, 6 years, into 4 periods. We analyzed the screw breach rate, lateral mass screw conversion (LMSC) rate, and reposition rate. We also compared the CPS placement accuracy in the initial 15, 20, and 30 patients with the other 147, 142, and 132 patients, respectively, to assess the number of procedures necessary to reach the learning curve plateau and to identify a reasonable accuracy rate. RESULT: The total number of planned CPS placements was 979. Our learning curve showed that the breach rate plateaus at 3% to 4%. The necessary numbers for safe and accurate CPS placement during learning curve were 30 patients and 170 screws. None of the patients undergoing CPS developed a neurologic or vascular complication. CONCLUSION: By following our 5 safety steps, the steady state for safety and accuracy can be reached without neurovascular complications even in the initial period of the learning curve.

Pedicle Screw Revision in Robot-Guided, Navigated, and Freehand Thoracolumbar Instrumentation: A Systematic Review and Meta-Analysis.

OBJECTIVE: Various computer-based guidance systems have been devised to reduce costly screw-related complications, yet their clinical effectiveness has never been comparatively assessed in a meta-analysis. We aimed to evaluate the incidence of clinically relevant pedicle screw revisions among robot-guided, navigated, and freehand spinal instrumentation. METHODS: Controlled trials comparing robot-guided, navigated, or freehand spinal instrumentation for any indication and that specifically reported the proportion of patients who experienced pedicle screw revisions were included. Estimates were pooled using random-effects meta-analyses. Sensitivity analyses including zero-event trials and assessing per screw incidences were carried out. RESULTS: Among 37 studies (7095 patients), intraoperative revisions in robot-guided (odds ratio [OR], 3.6; 95% confidence interval [CI], 0.7-19.4; P = 0.14) and navigated (OR, 1.5; 95% CI, 0.3-7.2; P = 0.64) procedures were comparable to freehand. Although postoperative revisions were reduced in robot-guided (OR, 0.3; 95% CI, 0.1-0.9; P = 0.04) and navigated (OR, 0.3; 95% CI, 0.2-0.5; P < 0.001) procedures, statistical significance was lost in sensitivity analyses for robotic guidance, but not for navigation. The pooled incidence of malpositioned screws requiring postoperative revision was 2.1%. CONCLUSIONS: Based on the available data in the peer-reviewed literature, computer assistance in the form of robotic guidance or navigation has the potential to reduce the incidence of costly and clinically relevant postoperative revisions for screw malposition. It is essential to further investigate on a higher level of evidence if the clinical benefits of computer assistance warrant the high acquisition and maintenance costs inherent to these systems.