Decompression alone versus decompression with instrumented fusion in the treatment of lumbar degenerative spondylolisthesis: a systematic review and meta-analysis of randomised trials.

OBJECTIVE: To determine the efficacy of adding instrumented spinal fusion to decompression to treat degenerative spondylolisthesis (DS). DESIGN: Systematic review with meta-analysis. DATA SOURCES: MEDLINE, Embase, Emcare, Cochrane Library, CINAHL, Scopus, ProQuest Dissertations & Theses Global, ClinicalTrials.gov and WHO International Clinical Trials Registry Platform from inception to May 2022. ELIGIBILITY CRITERIA FOR STUDY SELECTION: Randomised controlled trials (RCTs) comparing decompression with instrumented fusion to decompression alone in patients with DS. Two reviewers independently screened the studies, assessed the risk of bias and extracted data. We provide the Grading of Recommendations, Assessment, Development and Evaluation assessment of the certainty of evidence (COE). RESULTS: We identified 4514 records and included four trials with 523 participants. At a 2-year follow-up, adding fusion to decompression likely results in trivial difference in the Oswestry Disability Index (range 0-100, with higher values indicating greater impairment) with mean difference (MD) 0.86 (95% CI -4.53 to 6.26; moderate COE). Similar results were observed for back and leg pain measured on a scale of 0 to 100, with higher values indicating more severe pain. There was a slightly increased improvement in back pain (2-year follow-up) in the group without fusion shown by MD -5·92 points (95% CI -11.00 to -0.84; moderate COE). There was a trivial difference in leg pain between the groups, slightly favouring the one without fusion, with MD -1.25 points (95% CI -6.71 to 4.21; moderate COE). Our findings at 2-year follow-up suggest that omitting fusion may increase the reoperation rate slightly (OR 1.23; 0.70 to 2.17; low COE). CONCLUSIONS: Evidence suggests no benefits of adding instrumented fusion to decompression for treating DS. Isolated decompression seems sufficient for most patients. Further RCTs assessing spondylolisthesis stability are needed to determine which patients would benefit from fusion. PROSPERO REGISTRATION NUMBER: CRD42022308267.

The intraoperative portable CT scanner-based spinal navigation: a viable option for instrumentation in the region of cervico-thoracic junction.

PURPOSE: Innovative intraoperative imaging modalities open new horizons to more precise image acquisition and possibly to better results of spinal navigation. Planning of screw entry points and trajectories in this prospective study had been based on intraoperative imaging obtained by a portable 32-slice CT scanner. The authors evaluated accuracy and safety of this novel approach in the initial series of 18 instrumented surgeries in anatomically complex segment of cervico-thoracic junction. METHODS: We report on the single-institution results of assessment of anatomical accuracy of C5-T3 pedicle screw insertion as well as its clinical safety. The evaluation of total radiation dose and of time demands was secondary endpoint of the study. RESULTS: Out of 129 pedicle screws inserted in the segment of C5-T3, only 5 screws (3.9 %) did not meet the criteria for correct implant positioning. These screw misplacements had not been complicated by neural, vascular or visceral injury and surgeon was not forced to change the position intraoperatively or during the postoperative period. Quality of intraoperative CT imaging sufficient for navigation was obtained at all spinal segments regardless of patient´s habitus, positioning or comorbidity. A higher radiation exposition of the patient and 27 min longer operative time are consequences of this technique. CONCLUSIONS: The intraoperative portable CT scanner-based spinal navigation is a reliable and safe method of pedicle screw insertion in cervico-thoracic junction.

Applied anatomy of screw placement via the posterior arch of the atlas and anatomy-based refinements of the technique.

PURPOSE: To present a method of posterior arch and lateral mass screw (PALMS) insertion and to prove its feasibility. METHODS: Four formalin-fixed specimens and 40 macerated atlas vertebras were used to describe the relevant anatomy. The height of the posterior arch was measured on 42 consecutive patients using standard CT of the cervical spine. The operative technique and the special CT reconstructions used for preoperative planning are described. Eight patients underwent posterior fixation using this technique. RESULTS: We described the relevant anatomy and important anatomical landmarks of the posterior arch of the atlas. PALMS placement was modified according to these anatomical findings. Fifteen PALMSs were placed in eight patients using this technique without vascular or neural injury. CONCLUSION: It is feasible to place PALMS using the described technique. CT angiography is of crucial importance for preoperative planning using the described special reconstructions. The arch posterior to the lateral mass (APLM) is defined as the bone stock situated posterior to the lateral mass, respecting its convergence. The ideal entry point for a PALMS is on the APLM above the center of the converging lateral mass. A complete or incomplete ponticulus posticus and a retrotransverse foramen or groove can be used as an accessory landmark to refine the entry point.

Intraoperative portable CT-scanner based spinal navigation--a feasibility and safety study.

BACKGROUND: Navigation based on an intraoperative CT scan is not a new approach to spinal instrumentation. Innovative intraoperative imaging technology, however, opens new horizons to more precise image acquisition as well as to further workflow. Planning of screw entry-points and trajectories in this study had been based on intraoperative imaging obtained by a portable 32-slice CT scanner. This prospective study evaluates feasibility, accuracy, and safety of this novel approach in an initial series of 85 surgeries. METHOD: Medical records and radiological materials of 82 patients who underwent the first 85 consecutive stabilisations were analysed. Incorrect screw position, medical and technical complications as well as availability of this procedure in particular spinal levels were the subject of evaluation. RESULTS: Out of 571 implants inserted in all spinal levels, only five screws (0.87 %) did not meet the criteria for correct implant position. These screw misplacements had not been complicated by neural, vascular or visceral injury and the surgeon was not forced to change the position intraoperatively or during the postoperative period. The quality of intraoperative CT imaging sufficient for navigation was obtained at all spinal segments regardless of a patient's habitus or positioning or comorbidity. CONCLUSION: Intraoperative portable CT scanner-based navigation seems to be an effective way of doing spinal instrumentation guidance. High precision of implant insertion confirms the preconditions of navigation usage during more complex surgeries at any level of the spine.

Prognostic factors in intramedullary astrocytomas: a literature review.

Astrocytomas affect a significant portion of patients with intramedullary tumors. These infiltratively growing tumors are treated by a variety of methods -- biopsy and decompressive surgery, maximal safe resection, adjuvant oncological therapy. Also, numerous prognostic factors are reported in the literature. Better understanding of factors that influence prognosis may help in treatment planning with the goal of prolonging survival. We have thus undertaken an extensive literature review in order to define factors affecting prognosis. A total of 38 articles were studied. Only tumor grade was consistently reported as the major factor affecting prognosis. The influence of other clinical factors (age, gender, history length, functional status, tumor location or extent, syrinx or cyst presence) can be speculated upon, but cannot be assessed adequately from the available literature. For both low- and high-grade (HG) astrocytomas, maximal safe tumor resection should be the primary treatment objective but is often not feasible in contrast to other intramedullary and spinal neoplasms. Since the biological nature of spinal cord HG glioma is identical to that of the brain, the same treatment algorithm of maximal safe resection followed by concomitant radio- and chemotherapy would be sensible to implement.

Single-stage total C-2 intralesional spondylectomy for chordoma with three-column reconstruction. Technical note.

Chordomas are locally invasive, malignant bone tumors that rarely occur in the cervical spine. En bloc resection or even fully resecting the tumor along its margin offers improved patient survival and a potential disease cure. Complete resection of tumors involving the upper cervical vertebrae requires a combined anterior-posterior approach but is complicated by the presence of vertebral arteries (VAs). In addition, reconstruction of the postresection defect may be prone to failure. The authors present a case of a chordoma involving the axis that was treated using a single-stage total intralesional C-2 spondylectomy with preservation of both VAs because the patient did not tolerate a preoperative occlusion test. A three-column reconstruction technique is also presented.

Performance of radiofrequency ablation used for metastatic spinal tumor: Numerical approach.

Surgical treatment of spine metastases follows only local anatomical and biomechanical objectives. Few cases of actual solitary metastases are rather exceptional, while removal of these metastases and the primary tumor may help to eradicate the process. The aim of our subsequent numerical simulations was to find out the temperature distribution and the volume lesion in a spinal tumor. For this purpose, the parametric three-dimensional numerical model was developed. It was shown that by finite element modeling approach not only the temperature distribution but even the resulted cavity may be estimated. The numerical approach was shown as a strong tool in surgery planning.

Psychosocial Factors in Patients Indicated for Lumbar Spinal Stenosis Surgery.

In the context of the interdisciplinary care of patients with chronic back pain, surgery is an option for those who do not benefit from conservative treatment. Psychological assessment prior to back surgery aims to identify suitable candidates for surgery and predict possible complications or poor treatment effects. The literature suggests that psychosocial factors are important outcome predictors of lumbar spinal surgery; however, there is not enough empirical evidence to show that early identification and treatment of these factors help improve surgical outcome. This review discusses the possible psychosocial risk factors in patients with lumbar spinal stenosis who are undergoing decompression or stabilization surgery, shows the association between presurgical psychological parameters and surgical treatment outcome, and describes the characteristics of our pilot study to implement presurgical psychological assessment in routine clinical practice.

Factors affecting sagittal malalignment due to cage subsidence in standalone cage assisted anterior cervical fusion.

Fusion of cervical spine in kyphotic alignment has been proven to produce an acceleration of degenerative changes at adjacent levels. Stand-alone cages are reported to have a relatively high incidence of implant subsidence with secondary kyphotic deformity. This malalignment may theoretically lead to adjacent segment disease in the long term. The prospective study analysed possible risk factors leading to cage subsidence with resulting sagittal malalignment of cervical spine. Radiographic data of 100 consecutive patients with compressive radiculo-/myelopathy due to degenerative disc prolapse or osteophyte formation were prospectively collected in those who were treated by anterior cervical discectomy and implantation of single type interbody fusion cage. One hundred and forty four implants were inserted altogether at one or two levels as stand-alone cervical spacers without any bone graft or graft substitute. All patients underwent standard anterior cervical discectomy and the interbody implants were placed under fluoroscopy guidance. Plain radiographs were obtained on postoperative days one and three to verify position of the implant. Clinical and radiographic follow-up data were obtained at 6 weeks, 3 and 6 months and than annually in outpatient clinic. Radiographs were evaluated with respect to existing subsidence of implants. Subsidence was defined as more than 2 mm reduction in segmental height due to implant migration into the adjacent end-plates. Groups of subsided and non-subsided implants were statistically compared with respect to spacer distance to the anterior rim of vertebral body, spacer versus end-plate surface ratio, amount of bone removed from adjacent vertebral bodies during decompression and pre- versus immediate postoperative intervertebral space height ratio. There were 18 (18%) patients with 19 (13.2%) subsided cages in total. No patients experienced any symptoms. At 2 years, there was no radiographic evidence of accelerated adjacent segment degeneration. All cases of subsidence occurred at the anterior portion of the implant: 17 cases into the inferior vertebra, 1 into the superior and 1 into both vertebral bodies. In most cases, the process of implant settling started during the perioperative period and its progression did not exceed three postoperative months. There was an 8.7 degrees average loss of segmental lordosis (measured by Cobb angle). Average distance of subsided intervertebral implants from anterior vertebral rim was found to be 2.59 mm, while that of non-subsided was only 0.82 mm (P < 0.001). Spacer versus end-plate surface ratio was significantly smaller in subsided implants (P < 0.001). Ratio of pre- and immediate postoperative height of the intervertebral space did not show significant difference between the two groups (i.e. subsided cages were not in overdistracted segments). Similarly, comparison of pre- and postoperative amount of bone mass in both adjacent vertebral bodies did not show a significant difference. Appropriate implant selection and placement appear to be the key factors influencing cage subsidence and secondary kyphotisation of box-shaped, stand-alone cages in anterior cervical discectomy and fusion. Mechanical support of the implant by cortical bone of the anterior osteophyte and maximal cage to end-plate surface ratio seem to be crucial in the prevention of postoperative loss of lordosis. Our results were not able to reflect the importance of end-plate integrity maintenance; the authors would, however, caution against mechanical end-plate damage. Intraoperative overdistraction was not shown to be a significant risk factor in this study. The significance of implant subsidence in acceleration of degenerative changes in adjacent segments remains to be evaluated during a longer follow-up.

Heterotopic ossification in total cervical artificial disc replacement.

STUDY DESIGN: Prospective clinical study enrolled in 2 centers (Munich and Liberec) as part of a prospective European multicenter study with ProDisc C (Synthes Inc., Paoli, PA). OBJECTIVES: The first goal of the study was to evaluate the rate of heterotopic ossifications identified with plain radiograph following total cervical disc replacement (TCDR). The second goal was to show whether segmental motion can be preserved, and whether TCDR can provide improvement of the patient's ability to perform activities of daily living as well as a decrease of pain. SUMMARY OF BACKGROUND DATA: Only a few reports about the radiologic outcome after TCDR are published so far. Heterotopic ossification is a well-known phenomenon after total hip arthroplasty. The rate of heterotopic ossification following TCDR is unclear. METHODS: The radiographs of 54 patients (in total, 77 implanted prostheses) were analyzed 1 year after TCDR with a ProDisc C prosthesis. We classified the heterotopic ossification in 5 grades according to a recently published classification system for lumbar total disc replacement. For clinical parameters, the visual analog scale and the Neck Disability Index were evaluated preoperatively and 1 year postoperatively. The Student t test and Wilcoxon test were used for statistical analysis. RESULTS: In 26 treated segments (33.8%), no heterotopic ossification was detectable. Grade 1 ossifications were present in 6 levels (7.8%). A total of 30 segments (39.0%) showed grade 2 ossifications. Heterotopic ossifications that led to restrictions of the range of motion were present in 8 cases (10.4%). One year postoperatively, 7 cases (9.1%) had a spontaneous fusion of the treated segment. The clinical parameters improved significantly and were similar to previous reports about TCDR. CONCLUSIONS: Only 33.8% of the patients did not show any signs of heterotopic ossification, and the rate of spontaneous fusion after TCDR 1 year after surgery was unexpectedly high. There were 49.4% of the patients with grade 2-3 ossification, which lets us suspect an even higher rate of spontaneous fusion after long-term follow-ups. Motion preservation after TCDR is only guaranteed if spontaneous fusion can be prevented. Thus, mobility of the implanted segments needs to be further studied.

Autologous versus allogenic bone grafts in instrumented anterior cervical discectomy and fusion: a prospective study with respect to bone union pattern.

BACKGROUND: The purpose of this prospective semi-randomised comparative study was to compare fusion rates, course of fusion, and occurrence of collapse and subsidence of autologous and allogenic bone grafts in instrumented anterior cervical fusion. The number of fused levels and the smoking status were investigated as potential factors influencing the bone-healing process. No similar prospective study on instrumented anterior cervical discectomy and fusion was found in the literature. METHODS: Seventy-nine consecutive patients were operated on using the Smith-Robinson technique with a single instrumentation system at one or two levels. Seventy-six cadaverous fibular bone grafts and 37 autologous iliac-crest bone grafts were inserted. All patients were followed up for at least 2 years. RESULTS: The radiographs obtained during the follow-up were analysed, and showed no statistical difference in fusion and collapse rate between autografts and allografts. Allografts showed significantly longer time to union. No case of graft migration was observed. No difference was found between fusion and collapse rate with respect to the number of fused levels in general, but greater time to union was seen in two-level fusions. When one- and two-level subgroups were compared, there was no evidence of any significant difference in fusion or collapse rates between autografts and allografts, and the healing process took longer in allogenic grafts. Smoking status did not alter any of the fusion or collapse rates, or the course of bone fusion. CONCLUSIONS: This study demonstrates that allografts are suitable substitutes for autografts in instrumented ACDF. Prolonged time to union observed in allogenic bone grafts does not seem to be an important factor in instrumented procedures. Two-level grafting does not imply a significantly lower fusion rate, but longer time to union can be expected than with single-level instrumented procedures in both allograft and autograft subgroups. Our relatively small number of patients may not have been sufficient to decipher significant differences between smokers and non-smokers in the rate or course of fusion as previously reported.

Pyogenic osteomyelitis of the odontoid process: single stage decompression and fusion.

STUDY DESIGN: A case report. OBJECTIVES: To document our experience with single stage decompression and fixation in the treatment of pyogenic osteomyelitis of the odontoid process. SUMMARY OF BACKGROUND DATA: Although several investigators have reported a handful of these unusual cases, up until now, there have been no studies concerning a single stage solution in the surgical treatment of this pathology. METHODS: Three patients with osteomyelitis of the odontoid process caused by Staphylococcus aureus underwent surgical treatment in single sessions (transoral decompression combined with posterior fusion as the second step of the operation). Following surgery, the patients underwent a 6-week antibiotic course administered both intravenously and orally. Furthermore, we recommended the use of a hard cervical collar for 8 weeks together with isometric rehabilitation of the cervical muscles. Currently, follow-up results are available for two patients. RESULTS: On examination at 3 months, 6 months, and 1 year after the surgery, both patients had completely recovered with no neurologic deficit. Plain radiographs showed complete posterior fusion after 6 and 12 months, respectively. CONCLUSIONS: We emphasize the advantages of our method in comparison with nonoperative treatment or multisession surgery. The single stage surgical solution led to a shortening of hospitalization time with no need for halo bracing, to excellent results with respect to C-spine stability and to better compliance from the patients.