Christoph Mehren

Study Design: Retrospective bicentric Cohort Study. Objective: Posterior (PLIF) and transforaminal lumbar interbody fusion (TLIF) have been clinically proven for the surgical treatment of degenerative spinal disorders. Despite many retrospective studies, the superiority of either technique has not been proven to date. In the literature, the complication rate of the conventional PLIF technique is reported to be significantly higher, but with inconsistent complication recording. In this retrospective bicentric study, a less invasive PLIF technique was compared with the conventional TLIF technique and complications were recorded using the validated SAVES V2 classification system. Methods: 1142 patients underwent PLIF (702) or TLIF (n = 440) up to 3 levels in two specialized centers. Epidemiological data, intra- and postoperative complications during hospitalization and after discharge were analyzed according to SAVES V2. Results: The overall complication rate was 13.74%. TLIF-patients had slightly significant more complications than PLIF-patients (TLIF = 16.6%/PLIF = 11.9%, P = .0338). Accordingly, complications during revision surgeries were more frequent in the first cohort (TLIF = 20.9%/PLIF = 12.6%; P = .03252). In primary interventions, the surgical technique did not correlate with the complication rate (TLIF = 12.4%/PLIF = 11.7%). There were no significant differences regarding severity of complications. Conclusions: An important component of this work is the complication recording according to a uniform classification system (SAVES V2). In contrast to previous literature, we could demonstrate that there is not a significant difference between the two surgical techniques.

Objectives Workplace-based assessment (WBA) is a key requirement of competency-based medical education in postgraduate surgical education. Although simulated workplace-based assessment (SWBA) has been proposed to complement WBA, it is insufficiently adopted in surgical education. In particular, approaches to criterion-referenced and automated assessment of intraoperative surgical competency in contextualized SWBA settings are missing. Main objectives were (1) application of the universal framework of intraoperative performance and exemplary adaptation to spine surgery (vertebroplasty); (2) development of computer-assisted assessment based on criterion-referenced metrics; and (3) implementation in contextualized, team-based operating room (OR) simulation, and evaluation of validity. Design Multistage development and assessment study: (1) expert-based definition of performance indicators based on framework’s performance domains; (2) development of respective assessment metrics based on preoperative planning and intraoperative performance data; (3) implementation in mixed-reality OR simulation and assessment of surgeons operating in a confederate team. Statistical analyses included internal consistency and interdomain associations, correlations with experience, and technical and non-technical performances. Setting Surgical simulation center. Full surgical team set-up within mixed-reality OR simulation. Participants Eleven surgeons were recruited from two teaching hospitals. Eligibility criteria included surgical specialists in orthopedic, trauma, or neurosurgery with prior VP or kyphoplasty experience. Main outcome measures Computer-assisted assessment of surgeons’ intraoperative performance. Results Performance scores were associated with surgeons’ experience, observational assessment (Objective Structured Assessment of Technical Skill) scores and overall pass/fail ratings. Results provide strong evidence for validity of our computer-assisted SWBA approach. Diverse indicators of surgeons’ technical and non-technical performances could be quantified and captured. Conclusions This study is the first to investigate computer-assisted assessment based on a competency framework in authentic, contextualized team-based OR simulation. Our approach discriminates surgical competency across the domains of intraoperative performance. It advances previous automated assessment based on the use of current surgical simulators in decontextualized settings. Our findings inform future use of computer-assisted multidomain competency assessments of surgeons using SWBA approaches.

Das Deformitäten-Register befindet sich nun in seinem vierten Jahr. Mit der Kommissionsitzung, während der DWG Jahrestagung 2021 in Münster, habe ich die ehrenvolle Aufgabe erhalten, diese Kommission als Nachfolger von Prof. Liljenqvist zu leiten. Ich möchte Herrn Prof. Liljenqvist für seine zielstrebige und nachhaltige Organisation dieser Kommission, auch im Namen aller teilnehmenden Zentren, danken. Zudem freut es mich sehr, Prof. Geiger als stellvertretenden Kommissionsleiter gewonnen zu haben. Inzwischen beteiligen sich 10 Zentren mit über 10 eingeschlossenen Patienten, die die Motivation und auch die fachliche Expertise aufweisen, dieses spezielle Register mit Leben zu füllen. Zu Erinnerung – es werden die klinischen und radiologischen Daten von Patientinnen und Patienten erhoben, die auf Grund einer idiopathischen Skoliose operiert wurden und jünger als 18 Jahre waren. Als wissenschaftliches Ergebnis dieser Arbeit konnte die Kommission erste klinische Daten auf der Jahrestagung 2021 in Münster vortragen. Weitere Präsentationen der Ergebnisse mit längerem Follow-up und neuen Fragestellungen sind geplant. Zum aktuellen Zeitpunkt konnten deutlich über 400 Patienten in dieses Register eingeschlossen werden. Bis zum 1.4.2022 sollten bereits 300 Patienten das 1 -Jahres-Follow-up durchlaufen haben. Bei 128 Patienten steht zu diesem Zeitpunkt das 2-Jahres-Follow-up an. Da die Eingabe der klinisch relevanten Daten (allgemeine Registerfragebögen zur OP, SRS Fragebogen sowie ein Zusatzbogen Skoliose) über die „bekannte“ Registeroberfläche der DWG online durch die Chirurgen erfolgt, ist die Erfassung und die weitere Auswertung der Daten durch das ISPM in der Vergangenheit relativ problemlos abgelaufen. Die Besonderheit dieses Registers liegt in dem Fakt, dass auch definierte Röntgenbilder anonymisiert hochgeladen und durch einen externen Dienstleister vermessen und analysiert werden. Dies jedoch hat einige Zentren – und auch deren IT Abteilungen – vor große Herausforderungen gestellt und auch die Zahl der auswertbaren vollständigen Datensätze signifikant reduziert. Im Jahr 2022 wird nun großes Augenmerk auf die „Neuorganisation“ dieser Daten und der Datenverwaltung gelegt. Auch die Möglichkeiten weiterer Anbieter wird sondiert, die die Übertragung und Auswertung für die beteiligten Zentren deutlich vereinfachen sollen. Ein von allen Zentren gewünschtes, zeitnahes und einfach visualisierbares „feedback-System“ sollte in Zukunft implementiert werden, um die Datenqualität und die Auswertung signifikant zu verbessern. Bis zum aktuellen Zeitpunkt ist noch keine finale Entscheidung getroffen, jedoch bin ich zuversichtlich bald eine einvernehmliche, gute Lösung präsentieren zu können. Abschließend möchte ich allen beteiligten Zentren für ihre geleistete Arbeit und die notwendige Geduld meinen persönlichen Dank aussprechen. Article published online: 26 August 2022 © 2022. Thieme. All rights reserved. Georg Thieme Verlag KG Rüdigerstraße 14, 70469 Stuttgart, Germany

Study Design: Retrospective consecutive cohort study. Objective: For patients with mild to moderate adolescent idiopathic scoliosis (AIS), bracing is the standard therapy to prevent progression of deformity. Still, not all patients benefit from treatment in the same way. Therefore, predictive parameters are needed to determine if patients are likely to benefit from brace therapy. Methods: Fourty-five AIS patients treated with a Chêneau brace were evaluated retrospectively. Inclusion criteria were based on SRS-criteria. Whole spine X-rays were performed pre-brace, in-brace, and at least 6 months after termination of brace treatment. Gender, age, Risser’s sign, vertebral rotation determined by Nash and Moe grading system, in-brace correction and in-brace time per day were parameters evaluated. Treatment success and failure groups were compared to determine possible predictive parameters for successful brace treatment. Results: Chêneau brace treatment was successful preventing curve progression in 69%. We found significant differences between success and failure group concerning age (14 ± .22 vs 12.4 ± .4; P < .001) and Risser’s sign (1.71 ± .16 vs .5 ± .17; P < .001) at beginning of brace treatment. Most significantly, initial in-brace curve correction was correlated with successful outcome after brace treatment (r = .64 ( P < .001)). Conclusions: As one of few studies adhering to the criteria defined by the Scoliosis Research Society our study shows reliable predictive parameters for Chêneau brace treatment success in patients with AIS. Data shown in this paper will help to differentiate AIS patients who are likely to benefit from adequate bracing therapy from those who could rather benefit from early surgical treatment.

Study Design. Prospective single‐center study. Objectives. To assess the clinical and radiological outcomes after ACDF with 3D printed cellular titanium cages filled with bone marrow and to compare the clinical and radiological results with the current scientific literature. Methods. ACDF was performed monosegmentally under standardized conditions. X‐rays were analyzed to determine the range of motion, fusion rates, and subsidence preoperatively and 3 and 12 months postoperatively. Clinical outcome measurements included neck disability index (NDI), visual analogue scale (VAS) for brachialgia and cervicalgia, and patient satisfaction. Results. 18 patients were included in the study. The mean RoM decreased from 7.7^° ± 2.6 preoperatively to 1.7^° ± 1.1^° after 3 months and 1.8^° ± 1.2^° 12 months after surgery. The fusion rates were at 94.4% after 3 and 12 months. The mean subsidence was 0.9 mm ± 0.5 mm 3 months postoperatively and 1.1 mm ± 0.5 mm 12 months after surgery. The mean NDI improved significantly from preoperatively to 12 months postoperatively (34.6 ± 6.2 and 3.4 ± 4.1, respectively). The VAS‐neck also showed a large improvement from 5.8 ± 2.2 before and 1.3 ± 1.4 12 months after surgery, as did the VAS‐arm (6.4 ± 1.5 and 0.9 ± 1.6, respectively). Patient satisfaction was high throughout the follow‐up period. Conclusion. ACDF with a 3D printed titanium cage resulted in fast fusion without pathological subsidence. In comparison to other cage materials such as PEEK, the 3D printed titanium cage was noninferior in regard to its fusion rate and clinical results.

Study Design: Nonrandomized prospective trial. Objective: Several studies could demonstrate “learning curves” in almost every single surgical procedure for unexperienced surgeons. This is in sharp contrast to the rising quality requirements in public health care to provide surgical training at patients “expense.” The aim of this study was to visualize, measure, and set a baseline of the pressure load on the spinal nerve root during a simulated microdiscectomy on a standardized and validated model (RealSpine) under the influence of the level of surgical experience and individual skills. Methods: Five highly experienced spine surgeons and 5 trainees without considerable surgical experience were selected to perform a standardized microsurgical discectomy on a validated RealSpine simulator. Force-torque sensors were integrated in this simulator to measure the load on the nerve root. The forces were recorded every 125 ms. Results: We could identify cumulative for the total intervention as well as for defined single surgical steps of this procedure and as well in between the single subjects a significant higher tension and contusion forces on the nerve for the trainee group (Δp contusion 83-765 Nċs and Δp tension 159-1131 Nċs for the trainees. Δp contusion 16-171 Nċs and Δp tension 27-146 Nċs for the experts). Conclusion: We could measure a difference between unexperienced and experienced surgeons regarding the manipulations of the nerve root during a standardized simulated microdiscectomy. This possibility could be the starting point for a new and innovative surgical education to improve outcome without negative side effects of “learning curves.”

Operationsziel Minimalinvasive posteriore segmentale Instrumentation und intraartikuläre Fusion mit dem Facet Wedge. Indikationen Sämtliche Fusionsindikationen bei degenerativen Bandscheibenerkrankungen ohne nennenswerte translatorische Instabilität, Postnukleotomiesyndrom, Spondylarthrose, Diszitis. Kontraindikationen Translatorische Instabilitäten, Zustand nach Dekompression mit partieller Facettengelenkresektion, Spondylolyse im betroffenen Segment. Operationstechnik Über einen 3 cm langen Hautschnitt stumpfes transmuskuläres Eingehen auf das entsprechende Facettengelenk L1/2 bis L5/S1. Eröffnen der Gelenkkapsel und Darstellen des Gelenkspaltes. Entknorpelung der Gelenkflächen und Implantation eines Facet-Wedge-Implantates intraartikulär. Fixation des Implantats durch 2 winkelstabil eingebrachte Schrauben in den entsprechenden Facettengelenkanteilen. Weiterbehandlung Frühmobilisation nach Abklingen der Narkose unter Thromboseprophylaxe. Tragen einer rumpfstabilisierenden Orthese je nach Art und Ausdehnung des Eingriffes bis zu 12 Wochen. Keine Einschränkung bezüglich Gehstrecke, Stehen und Sitzen unmittelbar postoperativ nach Schmerzvorgabe. Ergebnisse Es wurden 27 Patienten im Zeitraum von 02/2015 bis 9/2017 mit insgesamt 31 versorgten Segmenten in die prospektive nicht randomisierte Studie eingeschlossen. Das Durchschnittsalter betrug 51,2 Jahre (30 bis 76). In 23 Fällen wurde eine ventrodorsale Operationstechnik verwendet, in 4 Fällen ein rein dorsales Vorgehen mit Interposition eines intervertebralen Cages. Das Follow-up betrug 2 Jahre. Der Oswestry-Score (Oswestry Disability Index [ODI]) verbesserte sich von durchschnittlich präoperativ 40,6 % auf 16,6 % postoperativ. Die visuelle Analogskala (VAS) bezüglich des Rückenschmerzes verbesserte sich von präoperativ 6,7 im Durchschnitt auf 2,1 im 2‑Jahres-Follow-up. Im Rahmen dieses Beobachtungszeitraumes wurden 2 implantatspezifische Komplikationen beobachtet. Ein Facet Wedge musste aufgrund einer Fehlpositionierung mit frühzeitiger Lockerung revidiert werden. In einem weiteren Fall kam es zu einem Korrekturverlust bei einer präoperativ bestehenden erstgradigen Spondylolisthese mit Revision auf ein dorsales Schrauben-Stab-System.