Use of an exoscope for enhanced visualization of a Schwab grade 5 osteotomy to correct kyphotic deformity

The development of the 3D exoscope has advanced intraoperative visualization by providing access to visual corridors that were previously difficult to obtain or maintain with traditional operating microscopes. Favorable ergonomics, maneuverability, and increased potential for instruction provide utility in a large range of procedures. Here, the authors demonstrate the exoscope system in a patient with progressive thoracolumbar junctional kyphosis with bony retropulsion of a T12–L1 fracture requiring a Schwab grade 5 osteotomy and fusion. The utilization of the exoscope provides visual access to the ventrolateral dura for the entire surgical team (surgeons, learners, and scrub nurse). The video can be found here: https://stream.cadmore.media/r10.3171/2021.10.FOCVID21190

Scheuermann’s disease surgery. Major problems: non-systematic literature review (part II)

Objective. To analyze literature data on the frequency of junctional kyphosis in surgery for Scheuermann’s disease, its relationship withspinopelvic parameters, risk factors and prevention of its development.Material and Methods. A search for sources in Scopus and Web of Science databases revealed 62 articles published from 1975 to 2021 and containing the required information. Of these, 56 publications meet the inclusion criteria.Results. The selected 56 articles contain data on 2,110 patients. In total, 247 (11.8 %) cases of proximal junctional kyphosis were diagnosed, including 6 (0.3 %) cases of proximal junctional failure. The total number of distal junctional kyphosis cases was 124 (5.9 %). Forty-five reoperations were performed. Many potential risk factors have been identified in publications, but there is no consensus on any of them.As a result, there is no a well-founded common position on the prevention of junctional kyphosis development. Spinopelvic parameters in Scheuermann’s disease are significantly less than those in the general population and do not tend to change after surgical correction of kyphosis. As for their relationship with the risk of development of proximal and distal junctional kyphosis, there is no consensus to date.Conclusion. This review is the largest in terms of coverage of literary sources on the problem of the development of junctional kyphosis in surgery for Scheuermann’s disease. The causes for the development of this complication remain unknown, hence there is the lack of generally accepted methods of prevention. New studies with long postoperative follow-up are needed.

Predicting development of severe clinically relevant distal junctional kyphosis following adult cervical deformity surgery, with further distinction from mild asymptomatic episodes

OBJECTIVE This retrospective cohort study aimed to develop a formal predictive model distinguishing between symptomatic and asymptomatic distal junctional kyphosis (DJK). In this study the authors identified a DJK rate of 32.2%. Predictive models were created that can be used with high reliability to help distinguish between severe symptomatic DJK and mild asymptomatic DJK through the use of surgical factors, radiographic parameters, and patient variables. METHODS Patients with cervical deformity (CD) were stratified into asymptomatic and symptomatic DJK groups. Symptomatic: 1) DJK angle (DJKA) > 10° and either reoperation due to DJK or > 1 new-onset neurological sequela related to DJK; or 2) either a DJKA > 20° or ∆DJKA > 20°. Asymptomatic: ∆DJK > 10° in the absence of neurological sequelae. Stepwise logistic regressions were used to identify factors associated with these types of DJK. Decision tree analysis established cutoffs. RESULTS A total of 99 patients with CD were included, with 32.2% developing DJK (34.3% asymptomatic, 65.7% symptomatic). A total of 37.5% of asymptomatic patients received a reoperation versus 62.5% symptomatic patients. Multivariate analysis identified independent baseline factors for developing symptomatic DJK as follows: pelvic incidence (OR 1.02); preoperative cervical flexibility (OR 1.04); and combined approach (OR 6.2). Having abnormal hyperkyphosis in the thoracic spine, more so than abnormal cervical lordosis, was a factor for developing symptomatic disease when analyzed against asymptomatic patients (OR 1.2). Predictive modeling identified factors that were predictive of symptomatic versus no DJK, as follows: myelopathy (modified Japanese Orthopaedic Association score 12–14); combined approach; uppermost instrumented vertebra C3 or C4; preoperative hypermobility; and > 7 levels fused (area under the curve 0.89). A predictive model for symptomatic versus asymptomatic disease (area under the curve 0.85) included being frail, T1 slope minus cervical lordosis > 20°, and a pelvic incidence > 46.3°. Controlling for baseline deformity and disability, symptomatic patients had a greater cervical sagittal vertical axis (4–8 cm: 47.6% vs 27%) and were more malaligned according to their Scoliosis Research Society sagittal vertical axis measurement (OR 0.1) than patients without DJK at 1 year (all p < 0.05). Despite their symptomatology and higher reoperation rate, outcomes equilibrated in the symptomatic cohort at 1 year following revision. CONCLUSIONS Overall, 32.2% of patients with CD suffered from DJK. Symptomatic DJK can be predicted with high reliability. It can be further distinguished from asymptomatic occurrences by taking into account pelvic incidence and baseline cervicothoracic deformity severity.

Planning Cervical Deformity Surgery Including DJK Prevention Strategies

Distal junctional kyphosis (DJK) is a major concern following cervical deformity (CD) correction, leading to failed realignment and revision surgery. In this chapter, we describe our approach to the treatment of cervical deformity and the steps taken to minimize the risk of DJK post-operatively by tailoring the construction to the individual patient. In this chapter, we describe our approach to the treatment of cervical deformity and the steps taken to minimize the risk of DJK post-operatively by tailoring the construction to the individual patient. First we focus on characterization of the baseline deformity. Secondly, we assess our patients clinically. Thirdly, we simulate the correction with the use of novel in-construct measurements. The fourth step is to develop a DJK prevention strategy tailored to the individual. The last step is to perform surgery and check correction during the operation.

Incidence and Radiological Risk Factors of Proximal Junctional Kyphosis in Adolescent Idiopathic Scoliosis Following Pedicle Screw Instrumentation with Rod Derotation and Direct Vertebral Rotation: A Minimum 5-Year Follow-Up Study

Several studies have reported incidence and risk factors for the development of proximal junctional kyphosis (PJK) in patients with adolescent idiopathic scoliosis (AIS). However, there is little information regarding long-term follow-up after pedicle screw instrumentation (PSI) with rod derotation (RD) and direct vertebral rotation (DVR). Sixty-nine AIS patients who underwent deformity correction using PSI with RD and DVR were retrospectively analyzed in two groups according to the occurrence of PJK, with a minimum five-year follow-up, including a non-PJK group (n = 62) and PJK group (n = 7). Radiological parameters were evaluated at preoperative, postoperative, and last follow-up. Incidence for PJK was 10.1% (7/69 patients), with a mean 9.4-year follow-up period. The thoracolumbar/lumbar curve (TL/L curve) was proportionally higher in the PJK group. The proximal compensatory curve was significantly lower in the PJK group than in the non-PJK group preoperatively (p = 0.027), postoperatively (p = 0.001), and at last follow-up (p = 0.041). The development of PJK was associated with the TL/L curve pattern, lower preoperative proximal compensatory curve, and over-correction of the proximal curve for PSI with RD and DVR. Therefore, careful evaluation of compensatory curves as well as of the main curve is important to prevent the development of PJK in the treatment of AIS.

Can Proximal Junctional Kyphosis After Surgery for Adult Spinal Deformity Be Predicted by Preoperative Dynamic Sagittal Alignment Change With 3D Gait Analysis? A Case–control Study

PurposeTo investigate whether preoperative dynamic spinal alignment that worsened during gait as detected by three-dimensional (3D) gait analysis can be a predictive factor for proximal junctional kyphosis (PJK) after corrective surgery for adult spinal deformity (ASD) with a minimum 1-year follow-up.MethodWe included 27 patients with ASD who underwent 3D gait analysis before corrective surgery and had >1-year follow-up. Dynamic spinal alignment parameters were obtained using a Nexus motion capture system (Vicon, Oxford, UK) with reflective markers. Spinal alignment was assessed in each region and pelvic alignment was assessed with surface markers. Patients were asked to walk for as long as possible around an oval walkway. We obtained the averaged dynamic parameters in the final lap and compared them between patients with PJK(+) and those with PJK(–).ResultsPJK occurred in 7 patients (26%). Preoperative angle between the thoracic spine and the pelvis was larger in patients with PJK(+) than in those with PJK(–) (32.3 ± 8.1 vs 18.7 ± 13.5, P = 0.020) with sufficient sample size. Multiple logistic regression analysis identified the angle between the thoracic spine and pelvis as an independent risk for PJK.ConclusionPreoperative thoracic kyphosis exacerbated by gait as determined in 3D gait analysis is a preoperative independent risk factor of PJK in patients undergoing ASD corrective surgery.

Health insurance policy on surgical treatment of adult spinal deformity

Background: Recent burgeoning research on adult spinal deformity (ASD) has unveiled the benefits of surgical treatment and how to gain the benefits although these have only been around for 10 years.Current Concepts: During the last decade, the significance of pelvic incidence in the global spinal sagittal alignment and introductions of the Scoliosis Research Society-Schwab classification for ASD have been the guidelines of surgical treatment for ASD and the milestones for promising surgical results. However, one of the unsolved problems for the surgical treatment of ASD is the proximal junctional kyphosis, for which multifactorial causative factors have been suggested. Recent studies have focused on dynamic natures in patients with ASD during daily activities, which might be a clue for both prevention of proximal junctional kyphosis and a better level of surgical results. Even though a recent remarkable advancement for surgical treatment for ASD is present, the national guideline for reimbursement is still following the surgical indication for lumbar degenerative kyphosis published in 1988.Discussion and Conclusion: A significant gap exists between the national reimbursement guideline and generally held surgical indication for ASD surgery. Consequently, this huge gap raises trouble in both patients and surgeons. The patients with ASD cannot take an appropriate surgery for ASD, while the spine surgeons experience unreasonable adjustment of the cost by the Health Insurance Review and Assessment Service.