Cervical Instrumented Fusion Research Articles

Instrumented cervical fusion using patient specific end-plate conforming interbody devices with a micro-porous structure in nine dogs with disk-associated cervical spondylomyelopathy.

To report the medium and long-term outcome of nine dogs with disk-associated cervical spondylomyelopathy (DA-CSM), treated by instrumented interbody fusion using patient specific end-plate conforming device that features a micro-porous structure to facilitate bone in-growth. A retrospective clinical study. Nine medium and large breed dogs. Medical records at two institutions were reviewed between January 2020 and 2023. Following magnetic resonance imaging (MRI) diagnosis of DA-CSM, pre-operative computed tomography (CT) scans were exported to computer software for in-silico surgical planning. Interbody devices were 3D-manufactured by selecting laser melting in titanium alloy. These were surgically implanted at 13 segments alongside mono-or bi-cortical vertebral stabilization systems. Follow-up included neurologic scoring and CT scans post-operative, at medium-term follow up and at long-term follow-up where possible. Interbody fusion and implant subsidence were evaluated from follow-up CT scans. Nine dogs were diagnosed with DA-CSM between C5-C7 at a total of 13 operated segments. Medium-term follow up was obtained between 2 and 8 months post-operative (3.00 ± 1.82 months). Neurologic scoring improved (p = 0.009) in eight of nine dogs. Distraction was significant (p < 0.001) at all segments. Fusion was evident at 12/13 segments. Subsidence was evident at 3/13 operated segments but was only considered clinically relevant in one dog that did not improve; as clinical signs were mild, revision surgery was not recommended. Long-term follow up was obtained between 9 and 33 months (14.23 ± 8.24 months); improvement was sustained in 8 dogs. The dog that suffered worsened thoracic limb paresis at medium-term follow up was also diagnosed with immune-mediated polyarthropathy (IMPA) and was euthanased 9 months post-operative due to unacceptable side-effects of corticosteroid therapy. End-plate conforming interbody devices with a micro-porous structure were designed, manufactured, and successfully implanted in dog with DA-CSM. This resulted in CT-determined fusion with minimal subsidence in the majority of operated segments. The technique described can be used to distract and fuse cervical vertebrae in dogs with DA-CSM, with favorable medium-and long-term outcomes.

Does Ending a Posterior Construct Proximally at C2 Versus C3 Impact Patient Reported Outcomes in Degenerative Cervical Myelopathy Patients up to 24months After the Surgery?

Retrospective cohort study. The primary objective was to evaluate the impact of the upper instrumented level (UIV) being at C2 vs C3 in posterior cervical construct on patient reported outcomes (PROs) up to 24months after surgery for cervical degenerative myelopathy (DCM). Secondary objectives were to compare operative time, intra-operative blood loss (IOBL), length of stay (LOS), adverse events (AEs) and re-operation. Patients who underwent a posterior cervical instrumented fusion (3 and + levels) with a C2 or C3 UIV, with 24months follow-up were analyzed. PROs (NDI, EQ5D, SF-12 PCS/MCS, NRS arm/neck pain) were compared using ANCOVA. Operative duration, IOBL, AEs, and re-operation were compared. Subgroup analysis was performed on patient presenting with pre-operative malalignment (cervical sagittal vertical axis ≥40mm and/or T1slope- cervical lordosis >15°). 173 patients were included, of which 41 (24%) had a C2 UIV and 132 (76%) a C3 UIV. There was no statistically significant difference between the groups for the changes in PROs up to 24months. Subgroup analysis of patients with pre-operative malalignment showed a trend towards greater improvement in the NDI at 12months with a C2 UIV (P = .054). Operative time, IOBL and peri-operative AEs were more in C2 group (P < .05). There was no significant difference in LOS and re-operation (P > .05). In this observational study, up to 24months after surgery for posterior cervical fusion in DCM greater than 3 levels, PROs appear to evolve similarly.

Predictive risk factors for mechanical complications after multilevel posterior cervical instrumented fusion.

Mechanical complications should be considered following the correction of multilevel posterior cervical instrumented fusion. This study aimed to investigate clinical data on the patients' pre- and postoperative cervical alignment in terms of the incidence of mechanical complications after multilevel posterior cervical instrumented fusion. Between January 2008 and December 2018, 156 consecutive patients who underwent posterior cervical laminectomy and instrumented fusion surgery of 4 or more levels and were followed up for more than 2 years were included in this study. Age, sex, bone mineral density (BMD), BMI, mechanical complications, and pre- and postoperative radiographic factors were analyzed using multivariate logistic regression analysis to investigate the factors related to mechanical complications. Of the 156 patients, 114 were men and 42 were women; the mean age was 60.38 years (range 25-83 years), and the mean follow-up duration of follow-up was 37.56 months (range 24-128 months). Thirty-seven patients (23.7%) experienced mechanical complications, and 6 of them underwent revision surgery. The significant risk factors for mechanical complications were low BMD T-score (-1.36 vs -0.58, p = 0.001), a large number of fused vertebrae (5.08 vs 4.54, p = 0.003), a large preoperative C2-7 sagittal vertical axis (SVA; 32.28 vs 23.24 mm, p = 0.002), and low preoperative C2-7 lordosis (1.85° vs 8.83°, p = 0.001). The clinical outcomes demonstrated overall improvement in both groups; however, the neck visual analog scale, Neck Disability Index, and Japanese Orthopaedic Association scores after surgery were significantly worse in the mechanical complication group compared with the group without mechanical complications. Low BMD, a large number of fused vertebrae, a large preoperative C2-7 SVA, and low C2-7 lordosis were significant risk factors for mechanical complications after posterior cervical fusion surgery. The results of this study could be valuable for preoperative counseling, medical treatment, or surgical planning when multilevel posterior cervical instrumented fusion surgery is performed.

Does extending a posterior cervical fusion construct into the upper thoracic spine impact patient-reported outcomes as long as 2 years after surgery in patients with degenerative cervical myelopathy?

In multilevel posterior cervical instrumented fusion, extension of fusion across the cervicothoracic junction (CTJ) at T1 or T2 has been associated with decreased rates of reoperation and pseudarthrosis but with longer surgical time and increased blood loss. The impact on patient-reported outcomes (PROs) remains unclear. The primary objective was to determine whether extension of fusion through the CTJ influenced PROs at 3, 12, and 24 months after surgery. The secondary objective was to compare the number of patients who reached the minimal clinically important differences (MCIDs) for the PROs, modified Japanese Orthopaedic Association (mJOA) score, operative time, intraoperative blood loss, length of stay, discharge disposition, adverse events (AEs), reoperation within 24 months of surgery, and patient satisfaction. This was a retrospective observational cohort study of prospectively collected multicenter data of patients with degenerative cervical myelopathy. Patients who underwent posterior instrumented fusion of 4 levels or greater (between C2 and T2) between January 2015 and October 2020 and received 24 months of follow-up were included. PROs (scores on the Neck Disability Index [NDI], EQ-5D, physical component summary and mental component summary of SF-12, and numeric rating scale for arm and neck pain) and mJOA scores were compared using ANCOVA and adjusted for baseline differences. Patient demographic characteristics, comorbidities, and surgical details were abstracted. The proportions of patients who reached the MCIDs for these outcomes were compared with the chi-square test. Operative duration, intraoperative blood loss, AEs, reoperation, discharge disposition, length of stay, and satisfaction was compared by using the chi-square test for categorical variables and the independent-samples t-test for continuous variables. A total of 198 patients were included in this study (101 patients with fusion not crossing the CTJ and 97 with fusion crossing the CTJ). Patients with a construct extending through the CTJ were more likely to be female and have worse baseline NDI scores (p > 0.05). When adjusted for baseline differences, there were no statistically significant differences between the two groups in terms of the PROs and mJOA scores at 3, 12, and 24 months. Surgical duration was longer (p < 0.001) and intraoperative blood loss was greater in the group with fusion extending to the upper thoracic spine (p = 0.013). There were no significant differences between groups in terms of AEs (p > 0.05). Fusion with a construct crossing the CTJ was associated with reoperation (p = 0.04). Satisfaction with surgery was not significantly different between groups. The proportions of patients who reached the MCIDs for the PROs were not statistically different at any time point. There were no statistically significant differences in PROs between patients with a posterior construct extending to the upper thoracic spine and those without such extension for as long as 24 months after surgery. The AE profiles were not significantly different, but longer surgical time and increased blood loss were associated with constructs extending across the CTJ.

185. A predictive model for C5 palsy after instrumented cervical fusion

<h3>BACKGROUND CONTEXT</h3> C5 palsy is a common postoperative complication of cervical fusion, occurring in 5-24% of patients. Although their prognosis is typically favorable, patients who develop C5 palsy are often unable to perform basic activities of daily living, resulting in increased health care costs and decreased quality of life. Accurate prediction of C5 palsy is thus of clinical utility. Predictive models assessing C5 palsy remain rare in the literature. <h3>PURPOSE</h3> We aim to build an ensemble ML algorithm for prediction of C5 palsy after instrumented cervical fusion. Furthermore, we aim to compare the performance of this model with logistic regression and other standard ML models. We hypothesize that the ML model will identify novel predictive features. <h3>STUDY DESIGN/SETTING</h3> Retrospective, cohort study. <h3>PATIENT SAMPLE</h3> Adult patients who underwent instrumented cervical fusion at a tertiary-care academic medical center between 2013-2020 were included. <h3>OUTCOME MEASURES</h3> The primary outcome was C5 palsy within index admission or follow-up encounters. <h3>METHODS</h3> We developed an ensemble ML model predicting C5 palsy risk using AutoPrognosis, an automated ML framework that configures an ensemble of ML-based models and traditional statistics. We compared this model with logistic regression and four ML models (XGBoost, gradient boosting, AdaBoost, random forest). Discrimination was assessed using area under the receiver operating characteristic curve (AUROC). Calibration was assessed using calibration slope and calibration intercept. We additionally ranked importance of each included feature for model performance utilizing a partial dependence function. <h3>RESULTS</h3> A total of 1,024 patients were included in this study, with 52 cases of C5 palsy (5.1%). The ensemble model demonstrated the highest discrimination (AUROC: 0.733) compared to regression (AUROC: 0.710). This model was well-calibrated with a calibration slope of 0.773 and a calibration intercept of -0.025. The following features were the most important for ensemble model performance: preoperative nonmotor neurologic symptoms, spinal trauma, corpectomy, spinal malignancy, posterior fusion, presence of paresthesias, psychiatric comorbidity, fixation for spinal fracture, degenerative disc disease, interbody fusion. Five of the 10 most important features for the ensemble model were markedly less important for regression. <h3>CONCLUSIONS</h3> We report a well-calibrated ensemble ML model that predicts C5 palsy after instrumented cervical fusion with high discrimination. This represents the first ML algorithm for prediction of C5 palsy after cervical fusion to our knowledge. Individualized risk prediction for patients may facilitate improved preoperative patient counseling and risk stratification. This tool may also aid with addressing potentially modifiable risk factors such as psychiatric comorbidity, helping to decrease likelihood of C5 palsy. <h3>FDA DEVICE/DRUG STATUS</h3> This abstract does not discuss or include any applicable devices or drugs.

A Risk Calculator for the Prediction of C5 Nerve Root Palsy After Instrumented Cervical Fusion

C5 palsy is a common postoperative complication after cervical fusion and is associated with increased health care costs and diminished quality of life. Accurate prediction of C5 palsy may allow for appropriate preoperative counseling and risk stratification. We primarily aim to develop an algorithm for the prediction of C5 palsy after instrumented cervical fusion and identify novel features for risk prediction. Additionally, we aim to build a risk calculator to provide the risk of C5 palsy. We identified adult patients who underwent instrumented cervical fusion at a tertiary care medical center between 2013 and 2020. The primary outcome was postoperative C5 palsy. We developed ensemble machine learning, standard machine learning, and logistic regression models predicting the risk of C5 palsy-assessing discrimination and calibration. Additionally, a web-based risk calculator was built with the best-performing model. A total of 1024 patients were included, with 52 cases of C5 palsy. The ensemble model was well-calibrated and demonstrated excellent discrimination with an area under the receiver-operating characteristic curve of 0.773. The following features were the most important for ensemble model performance: diabetes mellitus, bipolar disorder, C5 or C4 level, surgical approach, preoperative non-motor neurologic symptoms, degenerative disease, number of fused levels, and age. We report a risk calculator that generates patient-specific C5 palsy risk after instrumented cervical fusion. Individualized risk prediction for patients may facilitate improved preoperative patient counseling and risk stratification as well as potential intraoperative mitigating measures. This tool may also aid in addressing potentially modifiable risk factors such as diabetes and obesity.

Periprosthetic Osteolysis in Cervical Total Disc Arthroplasty: A Single Institutional Experience

ABSTRACT BACKGROUND Cervical disc arthroplasty (CDA) affords an excellent alternative to cervical fusion for the treatment of symptomatic patients with degenerative disc disease. As more surgeons perform CDAs, an understanding of the complications associated with this technique is crucial. Periprosthetic osteolysis (PO) is a rare potential complication associated with CDA. OBJECTIVE To highlight potential complications associated with CDA. METHODS A retrospective chart review of patients who underwent CDA at our institution was performed. Patient outcomes and relevant clinical and radiographical data were analyzed in addition to associated complications. Explanted devices were subjected to macroscopic and microscopic analyses. RESULTS A total of 88 patients were included: 68 patients underwent 1-level CDA and 20 patients had 2-level CDA. Implants used in this series included Mobi-C (Zimmer Biomet), Prestige LP (Medtronic), Secure C (Globus), Advent (Orthofix), and ProDisc C (DePuy). One patient demonstrated symptoms of myeloradiculopathy that correlated with radiographical periprosthetic osteolysis and required surgical intervention in the form of disc explantation, corpectomy, and cervical instrumented fusion. Device retrieval analysis demonstrated evidence of elevated oxidation levels and increased wear in the presence of high concentrations of metal ions and debris in the surrounding tissue. The tissue did not exhibit any immune response, infection, or acute inflammation. CONCLUSION PO is a potential complication of CDA that occurs irrespective of the type of implant used. We describe its occurrence and management and highlight the importance of being aware of this understated phenomenon.

Intradural primary marginal zone lymphoma of the cervical spine 2years following a posterior cervical instrumented fusion.

Primary low grade central nervous system lymphoma is a rare entity, with the majority being intracranial marginal zone B-cell lymphoma. Primary spinal lymphoma is unusual, and commonly presents as an epidural lesion with diffuse large B-cell histology, as described in prior literature. We present a case of a 56year-old woman diagnosed with a primary intradural spinal lymphoma two years after a posterior cervical fusion at the same level. She was treated successfully with surgical resection and postoperative radiotherapy. To our knowledge, this is the first case in the literature describing an intradural primary marginal zone B-cell lymphoma of the spine.

Adjacent Level Ossification Development Following Anterior Cervical Fusion: How Does it Affect the Next Level Disc?

Retrospective matched cohort analysis. The aim of this study was to investigate the impact of adjacent level ossification development (ALOD) on the affected as well as the next-level discs with regards to range of motion (ROM) and degenerative changes. Although ALOD is not a rare condition in patients who undergo anterior cervical fusion procedures, there has been little discussion to date about its clinical implications. Patients who underwent anterior cervical instrumented fusion with a minimum 2-year follow-up were reviewed. Twelve patients with each respective ossification grade (totally 48 patients) were matched based on age, sex, and number of fusion levels. On the preoperative and final follow-up x-rays, disc height, osteophytes, ROM, and maximal listhesis were assessed at the segments which were one- (the adjacent segment) and two-level cranial (the next segment) to the uppermost fused disc. Then, the patients were divided into two groups according to ALOD degree: group 1 (grade 0-1, N = 24) versus group 2 (grade 2-3, N = 24). The changes of all variables were compared between the two groups. The mean ROM of the adjacent segment increased by 3.6 degree in group 1 and conversely decreased by 2.8 degree in group 2 (P = 0.002). The mean ROM increase of the next segment was significantly greater in group 2 than in group 1 (4.5 vs. 1.2 degree, P = 0.016). The osteophyte growth and the progression of listhesis at the next segment were significantly greater in group 2 (P < 0.05). Disc height of the next segment significantly decreased in group 2, but did not change in group 1. Severe ALOD (grade 2-3) following anterior cervical fusion significantly reduced ROM at the affected segment and conversely increased motion at the next segment. This increased motion probably accelerated the degeneration of the next-level disc. 3.

Acute Implant-related Complications in Pediatric Cervical Spine Fusion.

The use of modern rigid instrumentation in pediatric cervical fusions decreases the risk of implant-related complications, both acute and long term. However, previous studies have indicated that acute implant-related issues still occur in the adult population. Reports of pediatric acute implant complications, occurring within 3 months of surgery, are under-represented in the literature. The purpose of this study is to document the prevalence of acute implant-related complications in a pediatric cervical fusion population. A retrospective review of instrumented cervical fusions from August 2002 to December 2018 was conducted. Acute implant-related complications were defined as malposition, fracture, or disengagement of cervical instrumentation, including screws, rods, and plates, within 90 days of surgery. A total of 166 cases were included (55% male individuals) with an average age at surgery of 12.5 years (SD, ±5.28). Acute implant-related complications occurred in 5 patients (3%). All 5 patients had a syndromic diagnosis: Loeys-Dietz (n=1), osteopetrosis (n=1), neurofibromatosis (n=1), trisomy 20 (n=1), and achondroplasia (n=1). One case involved asymptomatic screw protrusion, 1 case lateral mass screw pull-out, 2 more had screw-rod disengagement, and the last experienced dislodgement of the anterior plate. The median time until the presentation was 25 days (range, 1 to 79 d). All patients (n=5) required surgical revision. This case series suggests that the overall incidence of acute cervical implant failure is low. However, failure is more likely to occur in patients with underlying syndromes compared with patients with different etiologies. Intraoperative use of 3-dimensional computed tomography imaging is recommended to evaluate the screw position and potentially avoid later surgery.

Instrumented cervical fusion in nine dogs with caudal cervical spondylomyelopathy.

ObjectiveTo report the long‐term outcome of nine dogs treated for caudal cervical spondylomyelopathy (CCSM) with surgical spinal fusion.Study designShort case series.AnimalsNine large‐breed dogs.MethodsMedical records of dogs treated for disc‐associated CCSM (2013‐2016) were reviewed. The surgery objective was spinal distraction by implantation of a SynCage and fixation with two Unilock plates. Follow‐up included the Helsinki pain score questionnaire, neurological grading, radiography, computed tomography (CT), and micro‐CT (μCT) with subsequent histopathology (two dogs).ResultsClinical follow‐up was obtained between 9 and 51 months (27.4 ± 13.4 months). The Helsinki pain score and neurological Griffith score improved (P < .01) in all dogs and in eight of nine dogs, respectively. According to CT, the volume of bone (mean ± SD) through the cage was 79.5% ± 14.3%, including compact bone (53.0% ± 23.4%). Subsidence was seen in one of nine dogs. Implant failure was evident in four dogs, and plates were removed in two dogs. In seven of nine dogs, infraclinical pathology was observed in adjacent segment, associated with implants engaging adjacent intervertebral discs. Radiographic evidence of bony fusion between vertebral bodies was noted in all dogs. Spinal fusion was confirmed by μCT and histopathology in two cervical spine segments that became available at 22 and 40 months postoperatively.ConclusionInstrumented spinal fusion in dogs with disc‐associated CCSM resulted in owner satisfaction and radiographic evidence of interbody spinal fusion in all dogs.Clinical significanceThe fusion distraction technique reported here can be used to achieve spinal fusion with a good long‐term outcome.

Body mass index and the risk of deep surgical site infection following posterior cervical instrumented fusion

BACKGROUNDSurgical site infection (SSI) following spine surgery is associated with increased morbidity, reoperation rates, hospital readmissions, and cost. The incidence of SSI following posterior cervical spine surgery is higher than anterior cervical spine surgery, with rates from 4.5% to 18%. It is well documented that higher body mass index (BMI) is associated with increased risk of SSI after spine surgery. There are only a few studies that examine the correlation of BMI and SSI after posterior cervical instrumented fusion (PCIF) using national databases, however, none that compare trauma and nontraumatic patients. PURPOSEThe purpose of this study is to determine the odds of developing SSI with increasing BMI after PCIF, and to determine the risk of SSI in both trauma and nontraumatic adult patients. STUDY DESIGNThis is a retrospective cohort study of a prospective surgical database collected at one academic institution. PATIENT SAMPLEThe patient sample is from a prospectively collected surgical registry from one institution, which includes patients who underwent PCIF from April 2011 to October 2017. OUTCOME MEASURESA SSI that required return to the operating room for surgical debridement. METHODSThis is a retrospective cohort study using a prospectively collected database of all spine surgeries performed at our institution from April 2011 to October 2017. We identified 1,406 patients, who underwent PCIF for both traumatic injuries and nontraumatic pathologies using International Classification of Diseases 9 and 10 procedural codes. Thirty-day readmission data were obtained. Patient's demographics, BMI, presence of diabetes, preoperative diagnosis, and surgical procedures performed were identified. Using logistic regression analysis, the risk of SSI associated with every one-unit increase in BMI was determined. This study received no funding. All the authors in this study report no conflict of interests relevant to this study. RESULTSOf the 1,406 patients identified, 1,143 met our inclusion criteria. Of those patients, 688 had PCIF for traumatic injuries and 454 for nontraumatic pathologies. The incidence of SSI for all patients, who underwent PCIF was 3.9%. There was no significant difference in the rate of SSI between our trauma group and nontraumatic group. There was a higher rate of infection in patients, who were diabetic and with BMI≥30 kg/m2. The presence of both diabetes and BMI≥30 kg/m2 had an added effect on the risk of developing SSI in all patients, who underwent PCIF. Additionally, logistic regression analysis showed that there was a positive difference measure between BMI and SSI. Our results demonstrate that for one-unit increase in BMI, the odds of having a SSI is 1.048 (95% CI: 1.007–1.092, p=.023). CONCLUSIONSOur study demonstrates that our rate of SSI after PCIF is within the range of what is cited in the literature. Interestingly, we did not see a statistically significant difference in the rate of infection between our trauma and nontrauma group. Overall, diabetes and elevated BMI are associated with increased risk of SSI in all patients, who underwent PCIF with even a higher risk in patient, who are both diabetic and obese. Obese patients should be counseled on elevated SSI risk after PCIF, and those with diabetes should be medically optimized before and after surgery when possible to minimize SSI.

2447

OBJECTIVES/SPECIFIC AIMS: Cervical fusion is commonly performed for the management of degenerative disc disease, which can cause spinal stenosis and radiculopathy. Adjacent segment disease (ASD) is an adverse postsurgical outcome experienced by some patients as new radiculopathy, stenosis, or other symptomatic sequelae. We sought to assess whether fusion extension past the cervicothoracic junction reduces the risk of distal ASD after multilevel fusions ending at C7-T3. METHODS/STUDY POPULATION: We retrospectively reviewed all first-time patients undergoing instrumented cervical fusion of at least 2 spinal levels and whose distal level of fusion ranged from C7-T3, at the Johns Hopkins Medical Institutions, from 1999 to 2013. The primary outcome was reoperation for distal ASD. Using multiple logistic regression, ANOVA, and χ2 analysis, we determined the odds of ASD due to age, gender, distal level of fusion, surgical approach (anterior, posterior, or combined), smoking status, and race. RESULTS/ANTICIPATED RESULTS: Of the 158 patients who met the selection criteria, the mean age was 58.7±13.8 years, and 95 (60.1%) were female. Ten patients (6.3%) underwent reoperation for ASD. Patients whose fusions ended at C7 were significantly more likely to develop ASD and undergo reoperation (70%, p=0.007) than those whose fusions ended at T1. There were no differences in age, proximal fusion level, smoking status, BMI, gender, and patient-reported race between the reoperation and non-reoperation groups. Following a multivariable analysis, extending the distal fusion to T1 was again found to be protective against reoperation (OR=0.07, p=0.020). DISCUSSION/SIGNIFICANCE OF IMPACT: Our study shows that for multilevel instrumented cervical fusions that terminate within the cervicothoracic junction, fusion distal to the C7 vertebra is associated with decreased odds of reoperation for symptomatic ASD. Therefore, this study provides clinical evidence that may help surgeons determine the optimal distal fusion segment for multilevel fusions ending at C7-T3.

Surgical treatment of Type II odontoid fractures: anterior odontoid screw fixation or posterior cervical instrumented fusion?

Odontoid fractures comprise as many as 20% of all cervical spine fractures. Fractures at the dens base, classified by the Anderson and D'Alonzo system as Type II injuries, are the most common pattern of all odontoid fractures and are also the most common cervical injuries in patients older than 70 years of age. Surgical treatment is recommended for patients older than 50 years with Type II odontoid fractures, as well as in patients at a high risk for nonunion. Anterior odontoid screw fixation (AOSF) and posterior cervical instrumented fusion (PCIF) are both well-accepted techniques for surgical treatment but with unique indications and contraindications as well as varied reported outcomes. In this paper, the authors review the literature about specific patients and fracture characteristics that may guide treatment toward one technique over the other. AOSF can preserve atlantoaxial motion, but requires a reduced odontoid, an intact transverse ligament, and a favorable fracture line to achieve adequate fracture compression. Additionally, older patients may have a higher rate of pseudarthrosis using this technique, as well as postoperative dysphagia. PCIF has a higher rate of fusion and is indicated in patients with severe atlantoaxial misalignment and with poor bone quality. PCIF allows direct open reduction of displaced fragments and can reduce any atlantoaxial subluxation. It is also used as a salvage procedure after failed AOSF. However, this technique results in loss of atlantoaxial motion, requires prone positioning, and demands a longer operative duration than AOSF, factors that can be a challenge in patients with severe medical conditions. Although both anterior and posterior approaches are acceptable, many clinical and radiological factors should be taken into account when choosing the best surgical approach. Surgeons must be prepared to perform both procedures to adequately treat these injuries.

Preliminary documentation of the comparable efficacy of vitoss versus NanOss bioactive as bone graft expanders for posterior cervical fusion.

Background:Laminectomies with posterior cervical instrumented fusions often utilize bone graft expanders to supplement cervical lamina/iliac crest autograft/bone marrow aspirate (BMA). Here we compared posterior fusion rates utilizing two graft expanders; Vitoss (Orthovita, Malvern, PA, USA) vs. NanOss Bioactive (Regeneration Technologies Corporation [RTI: Alachua, FL, USA]).Methods:Two successive prospective cohorts of patients underwent 1-3 level laminectomies with 5-9 level posterior cervical fusions to address cervical spondylotic myelopathy (CSM) and/or ossification of the posterior longitudinal ligament (OPLL). The first cohort of 72 patients received Vitoss, while the second cohort or 20 patients received NanOss. Fusions were performed utilizing the Vertex/Rod/Eyelet System (Medtronic, Memphis, TN, USA) with braided titanium cables through the base of intact spinous processes (not lateral mass screws) cephalad and caudad to laminectomy defects. Fusion was documented by an independent neuroradiologist blinded to the study design, utilizing dynamic X-rays and two dimensional computed tomography (2D-CT) studies up to 6 months postoperatively, or until fusion or pseudarthrosis was confirmed at 1 year.Results:Vitoss and NanOss resulted in comparable times to fusion: 5.65 vs. 5.35 months. Dynamic X-ray and CT-documented pseudarthrosis developed in 2 of 72 Vitoss patients at one postoperative year (e.g. bone graft resorbed secondary to early deep wound infections), while none occurred in the 20 patients receiving NanOss.Conclusion:In this preliminary study combining cervical laminectomy/fusions, the time to fusion (5.65 vs. 5.35 months), pseudarthrosis (2.7% vs. 0%), and infection rates (2.7% vs. 0%) were nearly comparable sequentially utilizing Vitoss (72 patients) vs. NanOss (20 patients) as bone graft expanders.

Comparison of perioperative complications following staged versus one-day anterior and posterior cervical decompression and fusion crossing the cervico-thoracic junction

IntroductionMultilevel cervical pathology may be treated via combined anterior cervical decompression and fusion (ACDF) followed by posterior spinal instrumented fusion (PSIF) crossing the cervico-thoracic junction.The purpose of the study was to compare perioperative complication rates following staged versus same day ACDF combined with PSIF crossing the cervico-thoracic junction. Material and methodsA retrospective review of consecutive patients undergoing ACDF followed by PSIF crossing the cervico-thoracic junction at a single institution was performed.Patients underwent either same day (group A) or staged with one week interval surgeries (group B). The minimum follow-up was 12 months. ResultsThirty-five patients (14 females and 21 males) were analyzed. The average age was 60 years (37–82 years). There were 12 patients in group A and 23 in group B. Twenty-eight complications noted in 14 patients (40%) included: dysphagia in 13 (37%), dysphonia in 6 (17%), post-operative reintubation in 4 (11%), vocal cords paralysis, delirium, superficial incisional infection and cerebrospinal fluid leakage each in one case. Significant differences comparing group A vs. B were found in: the number of levels fused posteriorly (5 vs. 7; p=0.002), total amount of intravenous fluids (3233ml vs. 4683ml; p=0.03), length of hospital stay (10 vs. 18 days; p=0.03) and transfusion of blood products (0 vs. 9 patients). Smoking and cervical myelopathy were the most important risk factors for perioperative complications regardless of the group. ConclusionsStaging anterior cervical decompression and fusion with posterior cervical instrumented fusion 1 week apart does not decrease the incidence of perioperative complications.

Novel free-hand T1 pedicle screw method: Review of 44 consecutive cases.

Summary of Background Data:Multilevel posterior cervical instrumented fusions are becoming more prevalent in current practice. Biomechanical characteristics of the cervicothoracic junction may necessitate extending the construct to upper thoracic segments. However, fixation in upper thoracic spine can be technically demanding owing to transitional anatomy while suboptimal placement facilitates vascular and neurologic complications. Thoracic instrumentation methods include free-hand, fluoroscopic guidance, and CT-based image guidance. However, fluoroscopy of upper thoracic spine is challenging secondary to vertebral geometry and patient positioning, while image-guided systems present substantial financial commitment and are not readily available at most centers. Additionally, imaging modalities increase radiation exposure to the patient and surgeon while potentially lengthening surgical time.Materials and Methods:Retrospective review of 44 consecutive patients undergoing a cervicothoracic fusion by a single surgeon using the novel free-hand T1 pedicle screw technique between June 2009 and November 2012. A starting point medial and cephalad to classic entry as well as new trajectory were utilized. No imaging modalities were employed during screw insertion. Postoperative CT scans were obtained on day 1. Screw accuracy was independently evaluated according to the Heary classification.Results:In total, 87 pedicle screws placed were at T1. Grade 1 placement occurred in 72 (82.8%) screws, Grade 2 in 4 (4.6%) screws and Grade 3 in 9 (10.3%) screws. All Grade 2 and 3 breaches were <2 mm except one Grade 3 screw breaching 2-4 mm laterally. Only two screws (2.3%) were noted to be Grade 4, both breaching medially by less than 2 mm. No new neurological deficits or returns to operating room took place postoperatively.Conclusions:This modification of the traditional starting point and trajectory at T1 is safe and effective. It attenuates additional bone removal or imaging modalities while maintaining a high rate of successful screw placement compared to historical controls.

Modern instrumentation of the pediatric occiput and upper cervical spine: review article.

Rigid screw rod techniques for cervical stabilization are widely used in adults. The benefits of rigid internal fixation include increased fusion rates, improvements in deformity correction, and diminished immobilization requirements. Applications of these techniques in children are challenging due to size constraints and the pathologic conditions encountered which require instrumented cervical fusions. Preparation as well as thorough understanding of the anatomy and surgical techniques is paramount to surgical safety in pediatric patients. This review article serves as an educational tool regarding the use of modern posterior instrumentation techniques for pediatric cervical deformity. Expert review based on clinical expertise and literature review. The use of rigid screw rod instrumentation for the pediatric occiput and upper cervical spine is discussed. Preoperative imaging requirements for pediatric patients undergoing cervical spine surgery are reviewed. Anatomy, morphologic studies, and surgical techniques are discussed for each area of instrumentation. Modern posterior cervical instrumentation techniques can be safely applied to the majority of pediatric patients who require an instrumented posterior cervical fusion. Patient safety revolves around thorough preoperative imaging tests, understanding of upper cervical anatomy, and meticulous surgical technique. Modern instrumentation leads to an improvement in fusion rates and a diminishment in immobilization requirements.

Cervical spondylodiscitis associated with oesophageal perforation: a rare complication after anterior cervical fusion

Anterior cervical instrumented fusion is a commonly performed spinal surgery with relatively low complication rate. Especially, spinal infections are very rare and often associated with oesophageal perforation secondary to hardware migration. We present a rare complication of cervical spondylodiscitis in a 24-year-old man after an anterior cervical fusion. He had sustained a C5/C6 fracture dislocation associated with incomplete tetraplegia and he was treated by a combined staged posterior (lateral mass screws) and anterior (plate, PEEK) cervical fusion with an uneventful postoperative course with exception of light dysphagia for liquids. Three months after surgery, the patient developed fever and severe dysphagia. A barium-swallow study was indicative for oesophageal perforation, while MRI of the neck demonstrated spondylodiscitis C5/C6 accompanied by a prevertebral and epidural abscess. The treatment consisted of surgical debridement and evacuation of the abscesses, removal of the anterior spinal implants and insertion of a mesh cage with iliac bone graft. The weakened oesophagus posterior wall was enhanced with resorbable interrupted sutures and a 6-week course of antibiotics was administered. Dysphagia improved significantly while interbody fusion occurred 5 months following revision surgery. Five years postoperatively motor and sensor function had returned to normal limits. Dysphagia or deterioration of preexisted dysphagia in the late postoperative setting should be considered carefully and evaluated for oesophageal perforation and complicated spinal infection. In the case of not completed fusion, removal of the implants followed by meticulous debridement and insertion of titanium mesh cage, filled with autogenous bone graft lead to successful fusion and infection eradication.

The risk of adjacent-level ossification development after surgery in the cervical spine: are there factors that affect the risk? A systematic review.

Systematic review. To answer the following clinical questions: (1) What is the risk of adjacent-level ossification development (ALOD) in patients receiving noninstrumented cervical fusion, instrumented cervical fusion with a plate, or cervical total disc arthroplasty?; (2) What are the risk factors for ALOD?; (3) What is the time course for the development of ALOD?; and (4) Does ALOD affect outcomes and rates of reoperation? Anterior cervical plating, total disc arthroplasty, and noninstrumented fusion have all been used in the treatment of cervical disc disease. There are numerous reports that identify ALOD, a form of heterotopic ossification, as a major risk factor after performing these procedures. Few studies have compared these 3 procedures to evaluate the risk, timing, and outcomes related to postoperation ALOD. A systematic search was conducted in PubMed and the Cochrane Library for articles published between January 1, 1990, and December 31, 2011. We included all articles that described the risk of or risk factors for ALOD after surgical treatment of the cervical spine. Studies with patients older than 18 years or those treated for tumor or trauma were excluded from the study. In addition, those with posterior fusions, case reports, and case series with less than 10 patients were excluded. A total of 5 studies met the inclusion criteria for our systematic review. The risk of ALOD with anterior cervical discectomy and fusion ranged from 41% to 64%, whereas the risk of ALOD after total disc replacement ranged from 6% to 24%. When ALOD did occur, there was a 2-fold higher risk of development at the cranial adjacent segment. The most important risk factor for the development of ALOD was the use of instrumentation and the plate-to-disc distance, although the surgical procedure type (corpectomy vs. discectomy and fusion) neared but did not reach statistical significance. Insufficient evidence was available to delineate the time course for its development and how ALOD affected outcomes. The current body of literature suggests that ALOD will develop with the use of instrumentation and especially so if anterior instrumentation is placed within 5 mm of the adjacent cranial disc segment. In addition, total disc replacement showed lower rates for the development of ALOD compared with anterior cervical discectomy and fusion at both short- and long-term follow-up. We recommend that the surgeon make every effort to keep the plate as far away from the adjacent disc as possible. Strength of Statement: Strong.