Rapid qualitative analysis of recruitment obstacles in the FORVAD (Posterior Cervical Foraminotomy surgery versus Anterior Cervical Discectomy surgery in the treatment of cervical brachialgia) randomised, controlled trial.

BACKGROUND: The number of surgical trials is increasing but such trials can be complex to deliver and pose specific challenges. A multi-centre, Phase III, RCT comparing Posterior Cervical Foraminotomy versus Anterior Cervical Discectomy and Fusion in the Treatment of Cervical Brachialgia (FORVAD Trial) was unable to recruit to target. A rapid qualitative study was conducted during trial closedown to understand the experiences of healthcare professionals who participated in the FORVAD Trial, with the aim of informing future research in this area. METHODS: Semi-structured interviews were conducted with 18 healthcare professionals who had participated in the FORVAD Trial. Interviews explored participants' experiences of the FORVAD trial. A rapid qualitative analysis was conducted, informed by Normalisation Process Theory. RESULTS: Four main themes were generated in the data analysis: (1) individual vs. community equipoise; (2) trial set-up and delivery; (3) identifying and approaching patients; and (4) timing of randomisation. The objectives of the FORVAD trial made sense to participants and they supported the idea that there was clinical or collective equipoise regarding the two FORVAD interventions; however, many surgeons had treatment preferences and lacked individual equipoise. The site which had most recruitment success had adopted a more structured process for identification and recruitment of patients, whereas other sites that adopted more "ad hoc" screening strategies struggled to identify patients. Randomisation on the day of surgery caused both medico-legal and practical concerns at some sites. CONCLUSIONS: Organisation and implementation of a surgical trial in neurosurgery is complex and presents many challenges. Sites often reported low recruitment and discussed the logistical issues of conducting a complex surgical RCT. Future trials in neurosurgery may need to offer more flexibility and time during set-up to maximise opportunities for larger recruitment numbers. Rapid qualitative analysis informed by Normalisation Process Theory was able to quickly identify key issues with trial implementation so rapid qualitative analysis may be a useful approach for teams conducting qualitative research in trials. TRIAL REGISTRATION: ISRCTN, ISRCTN reference: 10,133,661. Registered 23rd November 2018.

In-office Maximal Voluntary Ventilation Testing Demonstrates Pulmonary Improvement Following Posterior Spinal Fusion for Adolescent Idiopathic Scoliosis.

OBJECTIVE: Pulmonary function can be impaired in patients with adolescent idiopathic scoliosis (AIS). Maximal voluntary ventilation (MVV) has been shown to be more strongly correlated with major coronal curve, and a more easily obtained measurement of pulmonary function, than forced vital capacity (FVC). We evaluated changes in pulmonary function using these 2 measures in patients with AIS in relation to changes in major coronal curves over time. METHODS: Forty-seven patients with AIS with thoracic curves ≥10 degrees performed pulmonary function tests using the Carefusion MicroLoop Spirometer at enrollment and 1 year later. Major coronal curve worsening >5 degrees was considered curve progression. RESULTS: At enrollment, 47 patients had a mean major coronal curve of 38 degrees (range: 10 to 76 degrees). One year later, 17 patients had undergone posterior spinal fusion, 9 had curve progression >5 degrees, and 21 had no progression. MVV and major coronal curve were negatively correlated (r = -0.36, P = 0.01) at enrollment. After fusion, the major coronal curve improved by a mean of 41 degrees, and MVV improved by 23% (P < 0.01), but FVC did not improve significantly (6%, P = 0.29). In stable curves, MVV improved 12% (P = 0.01) and FVC improved 9% (P = 0.007). In patients without surgery whose curves progressed an average of 11 degrees, there was no significant change in MVV or FVC (P > 0.44). CONCLUSION: This is the first study using office-based spirometry in an orthopaedic clinic showing improved pulmonary function with posterior spinal fusion and growth in patients with AIS. It is notable that MVV improved after spinal fusion, but FVC did not, as MVV appears to be a more sensitive measurement for the assessment of pulmonary function in these patients. LEVEL OF EVIDENCE: Level II.

Which lumbar vertebra should be the lowest level of fusion in adolescent idiopathic scoliosis of Lenke types 5 and 6?

OBJECTIVE:  It is important to protect the mobile segment in the lumbar region in scoliosis surgery. The aim of this study was to compare the clinical and radiological results of patients who underwent surgery for a diagnosis of adolescent idiopathic scoliosis (AIS) with the lowest instrumented vertebra (LIV) at L3 or L4 level. METHODS:  The study included 36 patients who underwent surgical treatment in our institution for a diagnosis of Lenke type 5 and 6 AIS with a follow-up period of at least 24 months. The patients were separated into 2 groups according to the LIV level of L3 (n=21) and L4 (n=15). These 2 groups were compared preoperatively (PO), early postoperative (EPO), and at the final follow-up examination (last control (LC)) with respect to radiological parameters in the coronal and sagittal planes, and the Scoliosis Research Society - 22 (SRS-22) questionnaire values. RESULTS:  In both groups the mean age (L3: 16 ± 7.3; L4: 17 ± 6.1 years) and follow-up periods (L3: 44 ± 20; L4: 47 ± 18 months) were similar. Radiologically, the L4 group had a greater Cobb angle in the scoliosis main curves measured PO (P=.001). The Cobb angles measured at EPO (P=.767) and at LC (P=.674) were similar in both groups. No significant difference was observed between the 2 groups in respect of the LIV tilt values at PO (P=.469), EPO (P=.297), and LC (P=.065). When the groups were evaluated separately, the LIV tilt values at EPO and LC were similar in the L4 group (EPO: 6.93 ± 3.058; LC: 7.26 ± 2.313; P=.618). In the L3 patients, although there seemed to be a significant increase in LIV tilt values when EPO values were compared with LC values (EPO: 8.47 ± 3.970; LC: 9.57 ± 3.76; P=.030), this was within the error range of Cobb angle measurement. The results of the SRS-22 questionnaire showed significantly better results in the L3 group in the domains of pain, function/activity, mental health, and satisfaction with treatment (P=.011, P=.002, P=.019, P=.046, respectively). CONCLUSION:  There was no radiological superiority between L3 and L4 LIV groups in the thoracolumbar/lumbar curve patients. However, according to the SRS-22 questionnaire, the results of patients with L3 level LIV were better in the areas of pain, function/activity, mental health, and satisfaction with treatment. Cite this article as: Baymurat AC, Tokgoz MA, Abdulaliyev F, Tosun MF, Can MM, Senkoylu A. Which lumbar vertebra should be the lowest level of fusion in adolescent idiopathic scoliosis of Lenke types 5 and 6? Acta Orthop Traumatol Turc., 2024;58(2):116-123.

Efficacy and safety of navigation robot-assisted versus conventional oblique lateral lumbar interbody fusion with internal fixation in the treatment of lumbar degenerative diseases: A retrospective study.

Effective internal fixation with pedicle screw is a key factor in the success of lumbar fusion with internal fixation. Whether navigation robots can improve the efficacy and safety of screw placement is controversial. Thirty-eight patients who underwent oblique lateral lumbar interbody fusion internal fixation from March 2022 to May 2023 were retrospectively analyzed, 16 cases in the navigational robot group and 22 cases in the fluoroscopy group. Using visual analog score (VAS) for the low back and lower limbs, Oswestry Disability Index to compare the clinical efficacy of the 2 groups; using perioperative indexes such as the duration of surgery, intraoperative blood loss, intraoperative fluoroscopy times, and postoperative hospital stay to compare the safety of the 2 groups; and using accuracy of pedicle screws (APS) and the facet joint violation (FJV) to compare the accuracy of the 2 groups. Postoperative follow-up at least 6 months, there was no statistically significant difference between the 2 groups in the baseline data (P > .05). The navigational robot group's VAS-back was significantly lower than the fluoroscopy group at 3 days postoperatively (P < .05). However, the differences between the 2 groups in VAS-back at 3 and 6 months postoperatively, and in VAS-leg and Oswestry Disability Index at 3 days, 3 months, and 6 months postoperatively were not significant (P > .05). Although duration of surgery in the navigational robot group was significantly longer than in the fluoroscopy group (P > .05), the intraoperative blood loss and the intraoperative fluoroscopy times were significantly lower than in the fluoroscopy group (P < .05). The difference in the PHS between the 2 groups was not significant (P > .05). The APS in the navigation robot group was significantly higher than in the fluoroscopy group, and the rate of FJV was significantly lower than in the fluoroscopy group (P < .05). Compared with the traditional fluoroscopic technique, navigation robot-assisted lumbar interbody fusion with internal fixation provides less postoperative low back pain in the short term, with less trauma, less bleeding, and lower radiation exposure, as well as better APS and lower FJV, resulting in better clinical efficacy and safety.

Evaluation of the use of tranexamic acid in the postoperative period in patients with scoliosis undergoing posterior fusion.

Scoliosis is the most prevalent type of spinal deformity, with a 2-3% prevalence in the general population. Moreover, surgery for scoliotic deformity may result in severe blood loss and, consequently, the need for blood transfusions, thereby increasing surgical morbidity and the rate of complications. Several antifibrinolytic drugs, such as tranexamic acid, have been regarded as safe and effective options for reducing blood loss. Therefore, the present study aimed to analyse the effectiveness of this drug for controlling bleeding when used intraoperatively and in the first 48 h after surgery. A prospective randomized study of a cohort of patients included in a mass event for scoliosis treatment using PSF was performed. Twenty-eight patients were analysed and divided into two groups: 14 patients were selected for intraoperative and postoperative use of tranexamic acid (TXA), and the other 14 were selected only during the intraoperative period. The drainage bleeding rate, length of hospital stay, number of transfused blood units, and rate of adverse clinical effects were compared. All the patients involved had similar numbers of fusion levels addressed and similar scoliosis profiles. The postoperative bleeding rate through the drain did not significantly differ between the two groups (p > 0.05). There was no significant difference in the number of transfused blood units between the groups (p = 0.473); however, in absolute numbers, patients in the control group received more transfusions. The length of hospital stay was fairly similar between the groups, with no statistically significant difference. Furthermore, the groups had similar adverse effects (p = 0.440), with the exception of nausea and vomiting, which were twice as common in the TXA group postoperatively than in the control group. No significant differences were found in the use of TXA during the first 48 postoperative hours or in postoperative outcomes.

[Cervical Spine Injuries]. / Verletzungen der oberen Halswirbelsäule.

Around a third of all cervical spine injuries occur in the upper cervical spine in the area between the occiput and the second cervical vertebra. The latter being the most common location of the injury with around 70%. But also atlas fractures, occipital condyle fractures, traumatic spondylolisthesis of C2, atypical fractures in the corpus area as well as atlantooccipital and atlantoaxial ligamentous lesions should be mentioned in connection with injuries in this area. In many cases, conservative therapy regimen is possible. In unstable or displaced injuries, however, surgical intervention is required, with various surgical procedures being used. The frequency, diagnostics, classification, and standard therapy of the individual entities are presented in detail in this continuing medical education article.

Adolescent Idiopathic Scoliosis in Siblings Treated by Surgical Deformity Correction.

Adolescent idiopathic scoliosis (AIS) in siblings reflects genetic hypothesis; however, few studies have been published. Furthermore, to the best of our knowledge, there have been no reports in the literature of both siblings with AIS who underwent deformity corrections. A 15-year-old adolescent girl visited our clinic with back pain after recognition of the incidental findings of a scoliotic curve in the spine. Whole spine radiographs detected Lenke classification type 3CN. The patient underwent deformity correction with posterior instrumented fusion from T4 to L3 with thoracoplasty of the right 7th to 10th rib. Four years later, her 16-year-old younger brother also visited our clinic with back pain after recognition of the incidental findings of a scoliotic curve in the spine. Whole spine radiographs detected Lenke classification type 2AN. The patient underwent deformity correction with posterior instrumented fusion from T5 to L2 with thoracoplasty of the right 8th to 10th rib. In conclusion, we report on two siblings with AIS who underwent surgical treatment for different types of curves. They showed favorable outcomes after performing deformity correction with posterior instrumented fusion. Our rare case supports the underlying basis of genetic heterogeneity as a complex polygenic model.

Decompression alone or with fusion for degenerative lumbar spondylolisthesis (Nordsten-DS): five year follow-up of a randomised, multicentre, non-inferiority trial.

OBJECTIVE: To assess whether decompression alone is non-inferior to decompression with instrumented fusion five years after primary surgery in patients with degenerative lumbar spondylolisthesis. DESIGN: Five year follow-up of a randomised, multicentre, non-inferiority trial (Nordsten-DS). SETTING: 16 public orthopaedic and neurosurgical clinics in Norway. PARTICIPANTS: Patients aged 18-80 years with symptomatic lumbar spinal stenosis and a spondylolisthesis of 3 mm or more at the stenotic level. INTERVENTIONS: Decompression surgery alone and decompression with additional instrumented fusion (1:1). MAIN OUTCOME MEASURES: The primary outcome was a 30% or more reduction in Oswestry disability index from baseline to five year follow-up. The predefined non-inferiority margin was a -15 percentage point difference in the proportion of patients who met the primary outcome. Secondary outcomes included the mean change in Oswestry disability index, Zurich claudication questionnaire, numeric rating scale for leg and back pain, and EuroQol Group 5-Dimension (EQ-5D-3L) questionnaire. RESULTS: From 12 February 2014 to 18 December 2017, 267 participants were randomly assigned to decompression alone (n=134) and decompression with instrumented fusion (n=133). Of these, 230 (88%) responded to the five year questionnaire: 121 in the decompression group and 109 in the fusion group. Mean age at baseline was 66.2 years (SD 7.6), and 69% were women. In the modified intention-to-treat analysis with multiple imputation of missing data, 84 (63%) of 133 people in the decompression alone group and 81 (63%) of 129 people in the fusion group had a at least a 30% reduction in Oswestry disability index, a difference of 0.4 percentage points. (95% confidence interval (CI) -11.2 to 11.9). The respective results of the per protocol analysis were 65 (65%) of 100 in the decompression alone group and 59 (66%) of 89 in the fusion group, a difference of -1.3 percentage points (95% CI -14.5 to 12.2). Both 95% CIs were higher than the predefined non-inferiority margin of -15%. The mean change in Oswestry disability index from baseline to five years was -17.8 in both groups (mean difference 0.02 (95% CI -3.8 to 3.9)). Results of the other secondary outcomes were in the same direction as the primary outcome. From two to five year follow-up, a new lumbar operation occurred in six (5%) of 123 people in the decompression group and 11 (10%) of 113 people in the fusion group, with a total from baseline to five years of 21 (16%) of 129 people and 23 (18%) of 125, respectively. CONCLUSIONS: In participants with degenerative spondylolisthesis, decompression alone was non-inferior to decompression with instrumented fusion five years after primary surgery. Proportions of subsequent surgeries at the index level or an adjacent lumbar level were no different between the groups. TRIAL REGISTRATION: ClinicalTrials.gov NCT02051374.

Comparison between the lowest instrumented vertebrae L3 with the use of direct vertebrae rotation (DVR) and the lowest instrumented vertebrae L4 for non-DVR in adolescents with idiopathic scoliosis Lenke 5C/6C: when LEV is L4.

OBJECTIVE: As there are no substantial selection criteria for determining the lowest instrumented vertebra (LIV) in adolescent idiopathic scoliosis (AIS) Lenke 5C/6C, thus, many surgeons base their selection on experience. The study aims to compare the selection of the lowest instrumented vertebrae (LIV) lumbar vertebra three (L3) with the use of direct vertebrae rotation (DVR) to the lowest instrumented vertebrae (LIV) lumbar vertebra four (L4) with the use of non-DVR for the correction of adolescent idiopathic scoliosis (AIS) Lenke 5C/6C when the lower end vertebrae (LEV) is at lumbar vertebrae four (L4). METHODS: This prospective study involved 101 patients who were divided into two groups based on different techniques. The patients were prospectively followed up for at least four years. All patients included in the study had a lower end vertebra (LEV) at L4, while patients older than 18 years and patients with prior surgical procedures were excluded. The DVR group consisted of 49 patients, and the non-DVR group included 51 patients. RESULTS: The preoperative mean LIV disc angle was 3.1 ± 3 and 3.1 ± 1, P = 0.097, which corrected to 1.2 ± 0 and 1.1 ± 0 in both groups at 4-year follow-up without statistical significance. The LIVDA and LIVT were statistically insignificant at the preoperative, and there were no significant differences at the follow-up visitation. The DVR group achieved a satisfactory coronal and Cobb's angle correction compared to the NDVR group; however, there were no statistical differences at the follow-up visitations. Both groups achieve a satisfactory correction rate without substantial significance in clinical and radiological outcomes. Furthermore, no post-surgical complications were recorded in either group. CONCLUSIONS: DVR is suitable for selecting L3 as the LIV in AIS Lenke 5C/6C compared to L4 in non-DVR. DVR preserved more segments without substantial complications during the follow-up visitations. Nevertheless, both groups will continue to be followed up to prevent adding-on post-surgical complications.

How I do it. Posterolateral lumbar spine fixation and decompression with navigation interfaced with a robotic exoscope with head mounted display.

INTRODUCTION: Lumbar spine fixation and fusion is currently performed with intraoperative tools such as intraoperative CT scan integrated to navigation system to provide accurate and safe positioning of the screws. The use of microscopic visualization systems enhances visualization and accuracy during decompression of the spinal canal as well. METHODS: We introduce a novel setting in microsurgical decompression and fusion of lumbar spine using an exoscope with robotized arm (RoboticScope) interfaced with navigation and head mounted displays. CONCLUSION: Spinal canal decompression and fusion can effectively be performed with RoboticScope, with significant advantages especially regarding ergonomics.

Posterior Sacroiliac Fusion Surgery: A Retrospective Single Center Study.

BACKGROUND: Chronic sacroiliitis has variable etiologies with numerous treatments of varying efficacy. In recent years, a novel posterior approach utilizing bone matrix has been developed although to date, there is limited data in the literature regarding efficacy and safety through this approach. Benefits described include reduced adverse outcomes and quicker recovery when compared to the lateral approach. OBJECTIVE: The present investigation focused on sacroiliac joint fusion through the posterior approach and outcomes including disability, pain, and use of analgesics post-surgery. STUDY DESIGN: This retrospective, single-center study was conducted evaluating safety and efficacy of sacroiliac fusion allograft implants (LinQ Implant System from PainTEQ; PsiF System from Omnia Medical). METHODS: A total of 72 posterior approach sacroiliac joint fusions were performed. Fifty-three individuals were enrolled and followed at LSU Health Shreveport as the sole investigational site between August 2020 and June 2024. Selected participant age ranged between 28 and 79 years, with a mean age of 53.4 years. The LinQ Implant System was the primary surgical hardware selected for implantation (83.0%), with the PsiF System chosen in the remaining cases. OUTCOME MEASURES: VAS Scores, disability changes, adverse outcomes, and analgesic use were compared after sacroiliac joint fusion via the posterior approach. RESULTS: Mean VAS Scores for SIJ Pain Intensity significantly decreased by 3.6 cm from a baseline score of 9.5 cm by the Specified End (June 1st, 2024). In this regard, 65.4% of patients experienced a 20% or greater improvement in pain, 38.5% of patients experienced a 50% or greater improvement in pain, and 26.9% of patients experienced a 70% or greater improvement in pain.  Zero (0) procedure-related adverse events nor intra- or post-operative complications occurred throughout the duration of the investigation. LIMITATIONS: Retrospective nature of the study without a control group. Fifty-four percent (39 of 72) completed minimum one year follow up. Further, the withdrawal rate was 26%. CONCLUSION: The results of the present investigation demonstrated effective outcomes with minimal adverse effects and improvements in disability over a three-year period in the largest single center study to date involving posterior approach sacroiliac joint fusion.

[Curative effect analysis of anterior cervical discectomy and fusion in patients with cervical spondylosis of vertebral artery type].

OBJECTIVE: To investigate the clinical effect of anterior cervical discectomy and fusion (ACDF) in the treatment of cervical spondylosis of vertebral artery type(CSA). METHODS: The clinical data of 42 patients with CSA from January 2020 to January 2022 were retrospectively analyzed. There were 25 males and 17 females, aged from 30 to 74 years old with an average of (53.9±11.0) years old. There were 18 cases with single-segment lesions, 17 cases with two-segment lesions, and 7 cases with three-segment lesions. The American Academy of Otolaryngology-Head and Neck Surgery's Hearing and Balance Committee score (CHE), the Neck Disability Index (NDI) and the cervical curvature Cobb angle were recorded before surgery and after surgery at 6 months. RESULTS: All 42 ACDF patients were followed up for 6 to 30 months with an average of (14.0±5.2) months. The operative time ranged from 95 to 220 min with an average of (160.38±36.77) min, the intraoperative blood loss ranged from 30 to 85 ml with an average of (53.60±18.98) ml. Tow patients had mild postoperative dysphagia, which improved with symptomatic treatment such as nebulized inhalation. CHE score decreased from (4.05±0.96) preoperatively to (2.40±0.70) at 6 months postoperatively (t=12.97, P<0.05). The number of improved vertigo at 6 months postoperatively was 38, with an improvement rate of 90.5%. NDI score was reduced from (34.43±8.04) preoperatively to (20.76±3.91) at 6 months postoperatively (t=11.83, P<0.05). The cervical curvature Cobb angle improved from (8.04±6.70)° preoperatively to (12.42±5.23)° at 6 months postoperatively (t=-15.96, P<0.05). CONCLUSION: The ACDF procedure has outstanding clinical efficacy in treating CSA. The operation can rapidly relieve patients' episodic vertigo symptoms by relieving bony compression and reconstructing cervical curvature. However, it is necessary to strictly grasp the indications for surgery and clarify the causes of vertigo in patients, and ACDF surgery is recommended for CSA patients for whom conservative treatment is ineffective.

Clinical performance of implanted devices used in surgical treatment of patients with spinal tumors: a systematic review.

PURPOSE: Implanted devices used in metastatic spine tumor surgery (MSTS) include pedicle screws, fixation plates, fixation rods, and interbody devices. A material to be used to fabricate any of these devices should possess an array of properties, which include biocompatibility, no toxicity, bioactivity, low wear rate, low to moderate incidence of artifacts during imaging, tensile strength and modulus that are comparable to those of cortical bone, high fatigue strength/long fatigue life, minimal or no negative impact on radiotherapy (RT) planning and delivery, and high capability for fusion to the contiguous bone. The shortcomings of Ti6Al4V alloy for these applications with respect to these desirable properties are well recognized, opening the field for an investigation about novel biomaterials that could replace the current gold standard. Previously published reviews on this topic have exhibited significant shortcomings in the studies they included, such as a small, heterogenous sample size and the lack of a cost-benefit analysis, extremely useful to understand the practical possibility of applying a novel material on a large scale. Therefore, this review aims to collect information about the clinical performance of these biomaterials from the most recent literature, with the objective of deliberating which could potentially be better than titanium in the future, with particular attention to safety, artifact production and radiotherapy planning interference. The significant promise showed by analyzing the clinical performance of these devices warrants further research through prospective studies with a larger sample size also taking into account each aspect of the production and use of such materials. METHODS: The Preferred Reporting Items for Systematic reviews and Meta-Analyses (PRISMA) guidelines were used to improve the reporting of the review. The search was performed from March 2022 to September 2023. RESULTS: At the end of the screening process, 20 articles were considered eligible for this study. Polyetheretherketone (PEEK), Carbon-fibre reinforced polyetheretherketone (CFR-PEEK), long carbon fiber reinforced polymer (LCFRP), Polymethylmethacrylate (PMMA), and carbon screw and rods were used in the included studies. CONCLUSION: CFR-PEEK displays a noninferior safety and efficacy profile to titanium implanted devices. However, it also has other advantages. By decreasing artifact production, it is able to increase detection of local tumor recurrence and decrease radiotherapy dose perturbation, ultimately bettering prognosis for patients necessitating adjuvant treatment. Nonetheless, its drawbacks have not been explored fully and still require further investigation in future studies. This does not exclude the fact that CFR-PEEK could be a valid alternative to titanium in the near future.

Implant Design and Cervical Spinal Biomechanics and Neurorehabilitation: A Finite Element Investigation.

INTRODUCTION: The cervical spine, pivotal for mobility and overall body function, can be affected by cervical spondylosis, a major contributor to neural disorders. Prevalent in both general and military populations, especially among pilots, cervical spondylosis induces pain and limits spinal capabilities. Anterior Cervical Discectomy and Fusion (ACDF) surgery, proposed by Cloward in the 1950s, is a promising solution for restoring natural cervical curvature. The study objective was to investigate the impacts of ACDF implant design on postsurgical cervical biomechanics and neurorehabilitation outcomes by utilizing a biofield head-neck finite element (FE) platform that can facilitate scenario-specific perturbations of neck muscle activations. This study addresses the critical need to enhance computational models, specifically FE modeling, for ACDF implant design. MATERIALS AND METHODS: We utilized a validated head-neck FE model to investigate spine-implant biomechanical interactions. An S-shaped dynamic cage incorporating titanium (Ti) and polyetheretherketone (PEEK) materials was modeled at the C4/C5 level. The loading conditions were carefully designed to mimic helmet-to-helmet impact in American football, providing a realistic and challenging scenario. The analysis included intervertebral joint motion, disk pressure, and implant von Mises stress. RESULTS: The PEEK implant demonstrated an increased motion in flexion and lateral bending at the contiguous spinal (C4/C5) level. In flexion, the Ti implant showed a modest 5% difference under 0% activation conditions, while PEEK exhibited a more substantial 14% difference. In bending, PEEK showed a 24% difference under 0% activation conditions, contrasting with Ti's 17%. The inclusion of the head resulted in an average increase of 18% in neck angle and 14% in C4/C5 angle. Disk pressure was influenced by implant material, muscle activation level, and the presence of the head. Polyetheretherketone exhibited lower stress values at all intervertebral disc levels, with a significant effect at the C6/C7 levels. Muscle activation level significantly influenced disk stress at all levels, with higher activation yielding higher stress. Titanium implant consistently showed higher disk stress values than PEEK, with an orders-of-magnitude difference in von Mises stress. Excluding the head significantly affected disk and implant stress, emphasizing its importance in accurate implant performance simulation. CONCLUSIONS: This study emphasized the use of a biofidelic head-neck model to assess ACDF implant designs. Our results indicated that including neck muscles and head structures improves biomechanical outcome measures. Furthermore, unlike Ti implants, our findings showed that PEEK implants maintain neck motion at the affected level and reduce disk stresses. Practitioners can use this information to enhance postsurgery outcomes and reduce the likelihood of secondary surgeries. Therefore, this study makes an important contribution to computational biomechanics and implant design domains by advancing computational modeling and theoretical knowledge on ACDF-spine interaction dynamics.

Is Posterior Cervical Foraminotomy Better Than Fusion for Warfighters?: A Biomechanical Study.

INTRODUCTION: Cervical spondylosis in the warfighter is a common musculoskeletal problem and can be career-ending especially if it requires fusion. Head-mounted equipment and increased biomechanical forces on the cervical spine have resulted in accelerated cervical spine degeneration. Current surgical gold standard is anterior cervical discectomy and fusion (ACDF). Posterior cervical foraminotomy (PCF) is a nonfusion surgical alternative, and this can be effective in alleviating radiculopathy from foraminal stenosis caused by disc-osteophyte complex. Biomechanical studies have not been done to analyze motion associated with military aircrew personnel following PCF. The aim of this study was to compare the biomechanical responses of the effects of ACDF and PCF with different grades of facet resection under simulated military aircrew conditions using range of motion, disc pressure, and facet loads at the index and adjacent levels. MATERIALS AND METHODS: A validated 3D finite element model of the human cervical spinal column was used to simulate various graded PCF and ACDF. All surgical simulations were performed at the most commonly operated level (C5-C6) in warfighters. Pure moment loading under flexion, extension, and lateral bending, and in vivo follower force of 75 N were applied to the intact spine. Hybrid loading protocol was used to achieve 134 degrees of combined flexion-extension and 83 degrees of lateral bending in intact and surgical models to reflect military loading conditions. Segmental motions, disc pressure, and facet load were obtained and normalized with respect to the intact model to quantify the biomechanical effect. RESULTS: Anterior cervical discectomy and fusion decreased range of motion at the index and increased motion at the adjacent levels, while all graded PCF responses had an opposite trend: increased motion at the index and decreased motion at adjacent levels. The magnitude of changes depended on the level of resection, spinal level, and loading mode. Disc pressure increased at the index level and decreased at the adjacent levels after PCF. These changes were exaggerated with increasing extent of facet resection. Facet load increased at the index level after PCF especially with extension and right (contralateral) lateral bending. Complete facetectomy led to facet load increases greater than ACDF at the adjacent levels in both flexion and extension. CONCLUSIONS: Posterior cervical foraminotomy is a motion-preserving implant-free surgical alternative to ACDF for warfighters with cervical radiculopathy after failure of conservative management. The treating surgeon must pay close attention to the extent of facet resection to avoid potential spinal instability and future disc and facet degeneration after PCF. Posterior cervical foraminotomy can be more advantageous than ACDF in terms of adjacent segment degeneration, motion preservation, reoperation rate, surgical cost, and retention of warfighters.

Individualized Design Application of 3-Dimensional Printing Navigational Template for Pedicle Screw Installation: A Training Case Report.

BACKGROUND The proper installation for pedicle screws by the traditional method of surgeons dependent on experience is not guaranteed, and educational solutions have progressed from chalkboards to electronic teaching platforms. We designed a case of 3-dimensional printing drill guide template as a surgical application, which can accurately navigate implantation of pedicle screws, and assessed its effect for simulative training. MATERIAL AND METHODS We randomly selected a set of computed tomography data for spondylolisthesis. A navigational template of pedicles and screws was designed by software Mimics and Pro-E, where trajectories of directions and angles guiding the nail way were manipulated for screwing based on anatomy, and its solid model was fabricated by a BT600 3D printer. The screws were integrated and installed to observe their stability. RESULTS The navigational model and custom spine implants were examined to be compatibly immobilized, because they are tolerant to radiation and stable against hydrolysis. The screw size and template were fit accurately to the vertebrae intraosseously, because the pilot holes were drilled and the trajectories were guided by cannulas with visible routes. During the surgical workflow, the patient reported appreciation and showed substantial compliance, while having few complications with this approach. Compared with fluoroscopy-assisted or free-hand techniques, the effect of simulative training during processing was excellent. CONCLUSIONS The surgical biomodel is practical for the procedural accuracy of surgical guides or as an educational drill. This fostering a style of "practice substituting for teaching" sets a paragon of keeping up with time and is worthy of recommendation.

Evaluation of the efficacy of posterior hemivertebrectomy combined with two or more segments fusion.

BACKGROUND: Although early hemivertebra (HV) resection and short fusion (within 4 segments) have been successful in treating congenital HV, there is limited research comparing the outcomes of the shortest-segment fusion (2 segments) versus 3 or 4 segments, particularly in young children. To evaluate the efficacy of posterior hemivertebrectomy combined with two or more segments fusion in children under the age of 10 years with a solitary simple lower thoracic or lumbar HV (T8-L5). METHODS: This retrospective study included patients under the age of 10 with lower thoracic or lumbar solitary simple HV who underwent hemivertebra resection (HVR) and transpedicular short fusion and were divided into HV ± 1 group (2 segment fusion) and HV ± 2 group (3 or 4-segment fusion). The study recorded preoperative, postoperative (1 week), and the latest follow-up radiographic parameters and complications. The results of the coronal and sagittal planes were analyzed, and the main curve, segmental scoliosis curve, compensatory scoliosis curve, segmental kyphosis curve, and trunk shift were compared. RESULTS: The study included 35 patients (15 in the HV ± 1 group and 20 in the HV ± 2 group) with a mean age of 5.26 ± 2.31 years and a mean follow-up of 22.54 months (12-68). The mean preoperative Cobb angle was 32.66° ± 7.339° (HV ± 1) and 29.31°±6.642° (HV ± 2). The final Cobb angle was 10.99°± 7.837° (HV ± 1) and 8.22° ± 4.295° (HV ± 2). The main curve corrected by 72% (HV ± 1), 75% (HV ± 2) postoperatively and 67% (HV ± 1), 72% (HV ± 2) at the final follow-up (P > 0.05). There were no significant differences in the correction of the segmental scoliosis curve, compensatory scoliosis curve, segmental kyphosis curve, and trunk shift between the HV ± 1 and HV ± 2 groups (P > 0.05). The unplanned reoperation rate for HV in the thoracolumbar region (T11-L2) is significantly higher (P = 0.038). CONCLUSION: In the context of solitary simple lower thoracic or lumbar HV (T8-L5), HV ± 1 segment fusion suffices and yields comparable correction outcomes in the midterm period when compared to HV ± 2. The reoperation rate exhibited a statistically significant increase in the thoracolumbar region.

The effect of chronic kidney disease on short-term single-level lumbar fusion outcomes.

INTRODUCTION: Chronic kidney disease (CKD) has an increasing global prevalence and has previously been associated with increased complications and morbidity after spine surgery. Understanding the isolated effect of CKD on short-term patient outcomes is critical for optimizing perioperative risk management and healthcare utilization. OBJECTIVE: The aim of this study is to utilize coarsened exact matching (CEM) to analyze the isolated effect of CKD on short-term patient outcomes in single-level posterior lumbar fusion surgery. METHODS: A retrospective analysis of 4680 consecutive patients undergoing single-level, posterior-only lumbar fusion was performed. Univariate logistic regression comparing the odds of outcomes in patients with CKD (n=40) to patients without medical comorbidities (n=2329) was performed. CEM was then employed to match patients with CKD to those without any comorbidities 1:1 on ten patient characteristics known to affect neurosurgical outcomes. Primary outcomes included intraoperative complications, length of stay, discharge disposition, and 30-day Emergency Department (ED) visits, readmissions, reoperations, and mortality. RESULTS: In a univariate logistic regression, CKD was associated with increased risk of 30-day ED visits (OR=3.53, p=0.003) but not complication, discharge disposition, or 30-day readmissions or reoperations. Between otherwise exactly matched patients (n=72), CKD similarly remained associated with an increased risk of 30-day ED visits (OR=7.00, p=0.034) and not with other outcomes. CONCLUSION: Between otherwise exactly matched patients undergoing single-level posterior lumbar fusion, CKD was related to increased risk of 30-day ED utilization but not other markers indicative of inferior surgical outcomes. Further study must investigate the reasons for increased ED visitation and implement risk-mitigation strategies for these patients.

Chest tube management following two row vertebral body tethering for adolescent idiopathic scoliosis.

BACKGROUND: The current gold standard of scoliosis correction procedures is still posterior spinal fusion, an extensively studied procedure. anterior vertebral body tethering is a newer surgical technique for the correction of scoliotic curves. Consequently, best practices have yet to be determined. METHODS: A single-institution, retrospective, review of all patients diagnosed with adolescent idiopathic scoliosis who underwent two row anterior vertebral body tethering between June 2020 and April 2022 was performed. RESULTS: Over the study period, 95 patients met inclusion: 79 females (83.2%) and 16 males (16.8%), age 14.4 ± 2.5 years, with a body mass index of 20.0 ± 2.9, and an average of 8.4 ± 2.1 levels treated. 28 (29.5%) procedures were for double curves and 67 (70.5%) for single curves. After tethering, a chest tube was positioned in each corrected side. A total of 123 chest tubes were analyzed, including 67 single curves and 28 double curves. The average chest tube duration was 2.5 ± 1.1 days and the average length of stay was 5.0 ± 2.0 days. The average chest tube output eight hours prior to removal was 61.1 ± 45.6 mL. There was no significant difference in average length of stay for patients who underwent correction of a single curve versus a double curve nor was there a difference in average length of stay or chest tube duration for revisions compared to primary procedures. For the entire cohort, the 30-day emergency department visit rate was 7.4% (n = 7) and the readmission rate was 4.2% (n = 4). CONCLUSIONS: This early review of a 2-year two row vertebral body tethering postoperative experience provides a report of a safe and effective approach to chest tube management at a single academic center.