Cervical Fixation Research Articles

Spinous Process Screw Fixation: A Salvage Technique in Subaxial Cervical Spinal Instrumentation

We sought to evaluate the feasibility and efficacy of spinous process screws in subaxial cervical fixation. A retrospective study was conducted on 7 patients receiving posterior cervical instrumentation for subaxial fracture dislocation or atlantoaxial dislocation from 2014 to 2015. In addition, a biomechanical test was performed on 7 fresh-frozen cadaveric spine samples (from the occiput to C7) from healthy human subjects with no history of spinal trauma. And lastly, the potential trajectories of cervical spinous process screws of 100 adults were measured through axial computed tomography in order to establish the general rule for applicability of this technique. Rigid fixation and solid fusion were achieved in all 7 patients included in the study. Biomechanical test results revealed no significant difference between bilateral lateral mass screw fixation and the hybrid lateral mass and spinous process screw fixation constructs. Measurement of the potential trajectory suggested that spinous process screw fixation was a viable technique in the subaxial cervical spine in the general population. The spinous process screw fixation technique in the subaxial cervical spine is a viable and effective salvage option for patients in whom conventional posterior fixations were not sufficient and salvage, supplementary techniques were required.

Versatile Usage of the Modified Lateral Mass Screw as an Alternative to Cervical Pedicle Screw Fixation.

Posterior subaxial cervical screw fixation is commonly performed using the cervical pedicle screws (CPS) and lateral mass screws (LMS); however, their compatibility is low. Modified lateral mass screws (mLMS, also called paravertebral foramen screw) fixation was introduced as a salvage technique for LMS fixation and has features of both LMS and CPS techniques. In the present study, the use of mLMS as an alternative to CPS was analyzed based on clinical results. Seventy-eight screws (38 CPSs and 40 mLMSs) were inserted into 12 patients. The misplacement of the screws was evaluated by computed tomography (CT). The failure of instrumentation and instability were evaluated using plain radiographs. The total number of CPS misplacements was 3 (10.5%); however, neurologic complications were not observed. mLMSs were used in the middle segments of the fusion in 10 patients and 2 patients had mLMS fixation for single-level fusion. An additional bridging implant was not required for connecting both CPSs and mLMSs. Instability was not observed during the observation period (4-51 months). Complete fusion was seen in 10 patients. The alternative mLMS fixation can decrease the risk of screw misplacement compared with CPS fixation alone and achieves adequate stability leading to fusion.

Pedicle screw placement with use of a navigated surgical drill at subaxial cervical spine

Study designRetrospective cohort study. ObjectiveThis study was performed to evaluate the accuracy of cervical pedicle screw (CPS) placement with use of a navigated surgical drill (ND) and to compare it with navigated manual probe (MP) at C3–C6. Methods47 consecutive patients (27 males and 20 females, 67.2 [33–91] years) underwent a posterior cervical fixation using CPSs under an intraoperative 3D - – CT based navigation system (total 207 CPSs). For initial probing, ND with 2.2-mm steel burr was used since Apr. 2017 (Group ND; 33 patients, 152 CPSs). MP was used earlier (Group MP; 14 patients, 55 CPSs). There were no other different procedures between the two groups. The accuracy of CPS placement was graded with postoperative CT and compared between the two groups. ResultsThere were no significant differences in the total perforation rates both in axial and sagittal planes between Groups ND and MP (axial; 7.2% vs. 14.5%, p = 0.25, sagittal; 10.5% vs. 14.5%, p = 0.46). However, the lateral and rostral perforation rates were significantly reduced in Group ND compared to Group MP (lateral: 36.4% vs. 87.5%, p = 0.04; rostral: 6.3% vs. 100%, p = 0.001). ConclusionAlthough ND did not decrease the total perforation rate significantly, it reduced the incidence of lateral and rostral perforation. ND is likely to make initial probing easier without a forcible manipulation which might cause vertebral rotation.

Anterior Plate-Screws and Lower Postoperative T1 Slope Affect Cervical Allospacer Failures in Multi-Level ACDF Surgery: Anterior Versus Posterior Fixation.

Prospective observational study. In ACDF, graft failure and subsidence are common complications of surgery. Depending on the cervical fixation, different biomechanical characteristics are applied on the grafts. This aims to describe the incidence of cervical spacer failure in patients with cervical degenerative condition according to the cervical fixation method and sagittal balance. From November 2011 to December 2015, 262 patients who underwent cervical spine surgery were enrolled prospectively. Patients were divided into 3 groups based on fixation method: anterior plate/screw (APS), posterior lateral mass screw (LMS), pedicle screw (PPS) groups. Serial X-rays and CT scans were utilized to evaluate radiologic outcomes. Mean patient ages were 56.1 years in the APS group, 61.5 years in the LMS group, and 57.6 years in the PPS group (P = 0.002). Allospacer failure was most common in the APS group, compared to the LMS and PPS groups (chi-square, P = 0.038). Longer fusion level was associated with greater allospacer failure (Baseline 2 level surgery; Odds ratio (OR) 3.4 in 3 level, 15.2 in 4 level, P = 0.036,0.013). Higher T1 slope was correlated with less allospacer failure (OR 0.875, P = 0.001). ORs of allospacer failure in the LMS and PPS groups were 0.04 and 0.02, respectively, (P = 0.01, 0.01), compared with the APS group. This study was able to show that allospacer failure in multi-level ACDF surgery is more common with a longer fusion length, less postoperative T1 slope, and an anterior plate-screws technique. Pedicle screws provided the best biomechanical stability among the 3 constructs.

Accuracy of Subaxial Cervical Pedicle Screw Placement Using Direct Visualization Versus Computed Tomography-Based Navigation.

Retrospective analysis of operative data from cadaveric cervical spines. To evaluate the accuracy of neuronavigation compared with laminotomy with direct visualization (DV) of the pedicle for placement of subaxial pedicle screws. Subaxial pedicle screws provide superior fixation compared with other posterior cervical fixation strategies. However, high accuracy is required for safe placement, given the proximity of critical neurovascular structures. Computed tomography (CT)-based neuronavigation has increased in popularity for placement of spinal implants, including subaxial pedicle screws. However, the accuracy of the technique for this application has not been extensively evaluated. Six fresh-frozen cadaveric spines (occiput to T2) were prepared. Pedicle screws were placed from C3 to C7 on either side using either the DV or neuronavigation technique (alternating sides between specimens). Pedicles with diameters <4 mm were excluded. For the DV technique, a hemilaminotomy was performed for DV of pedicle borders and to determine appropriate screw medialization and trajectory. Neuronavigation screws were placed using CT-based navigation with a reference frame mounted on the C2 spinous process. Screw position was evaluated using postoperative CT, and breaches were classified using the Neo classification. Fifty pedicle screws were placed at 25 levels in 6 cadaveric spines; 25 screws each were placed using neuronavigation or DV. No significant difference in accuracy was found between the 2 techniques. Three (12%) breaches occurred in the DV group, and 9 (36%) breaches occurred in the neuronavigation group (P=0.10). The breaches were evenly distributed across all levels. There were no high-grade breaches with DV and only 1 (4.0%) with neuronavigation (P>0.99). Average pedicle cortical and medullary bone widths were higher for levels with no breach (P=0.009 and P=0.02, respectively). High accuracy can be achieved with both neuronavigation and DV for placement of subaxial cervical pedicle screws in cadavers.

Application of the Life-Size Patient-Specific Three-Dimensional Cervical Spine Anatomical Model for Odontoid Fracture Fixation

Objective: Cervical fixation is the most common treatment of vertebral fractures, osteosarcoma, osteomyelitis, arthritis, and congenital disorders. Mortal complications, such as internal carotid artery, vertebral artery (VA), and spinal cord damages, may occur during the application. The aim of this study was to create the application of the actual three-dimensional (3D) personalized model which was exercised for screwing insertion in C2 damage patients. Methods: Two patients with Type II of C2 fractures were treated with personalized spine models. These models were investigated to achieve particular information of non- and bony elements such as the highness, thickness, and the field of pedicles and vascular diameters for an intraoperative reference. The model was to determine the probable variations and to observe the success of screw rate in the treatment of C2 fractures. The operation duration, instrumentation time, blood loss volume, and clinical and radiological assessment were done. The 3D model's perception was evaluated. Results: Cervical models were defined to secure intervention areas of the VA pedicles and screws. Neither vascular nor neurologic damages were happened in all cases. Besides, the cases did not include broken nails, screw pullout, fracture of bone structure, or infection. Cervical models demonstrated (1) examination of the VA pattern, (2) valuation of virtual screw trajectory line before screw fixation, (3) the application of prebent rods during procedure to contribute to the safety of the posterior instrumentation, (4) postsurgical confirmation, and (5) examined movements of the neck postoperatively. The perception of 3D model for treating C2 fracture was thereby diminishing surgical time, bleeding amount and operative complications. Survey perception of model was calculated in statistical significance (P &lt; 0.05). Conclusion: Personalized model is active and confident in achieving an accurate and safe screw fixation during surgery, especially in anatomically abnormal cases. Cervical model provides an accurate representation of the fracture location, pedicle size, and VA shapes. It is therefore useful in surgical planning as it maximizes the possibility of ideal screw position, as well as providing individualized information concerning cervical spinal anatomy.

Awake tracheal intubation with the ProVu™ video stylet: a case series*

Management of the difficult airway is integral to peri-operative practice. The development of devices to simplify airway handling are changing our approach to tracheal intubation. We report a case series of three patients who underwent awake tracheal intubation with the ProVu™ video stylet (Flexicare Medical Ltd, Mountain Ash, UK). All three patients had predicted difficult airways, including: limited mouth opening secondary to radiotherapy; previous exenteration, hemi-maxillectomy and scapular free flap formation; and cervical fixation. Awake tracheal intubation was performed successfully in all three cases, with no complications reported. This is the first reported case series of the ProVu™ video stylet as an awake tracheal intubation device. The benefits and limitations of this video stylet are discussed.

Novel use of percutaneous cervical pedicle inlet screws for supplemental posterior fixation after anterior cervical deformity correction.

Introduction:Correction of cervical deformity can be achieved using anterior cervical fixation and fusion techniques. However, supplemental posterior fixation is a critical component for ensuring biomechanical longevity and favorable patient outcomes. We present a novel percutaneous technique for posterior cervical fixation in patients where cervical pedicle (CP) screws may not be feasible and midline muscle dissection is not needed.Methods:Three patients presented to our hospital with cervical pathology amendable to circumferential cervical fusion. After adequate deformity correction was performed through an anterior cervical decompression and fusion, staged posterior supplemental fixation was achieved using percutaneous CP inlet (CPI) screws using a percutaneous muscle-sparing approach.Results:All three patients underwent CPI screw placement without postoperative neurovascular complications. Postoperative radiographic follow-up showed the desired, proper screw placement, with continued maintained cervical alignment.Conclusions:CPI screw placement may be alternative hybrid screw that achieves a advantageous safety profile while also avoiding an open midline exposure.

Posterior cervical fixation for atlantoaxial subluxation with fenestrated vertebral artery; a case report

Posterior cervical fixation for atlantoaxial subluxation with fenestrated vertebral artery; a case report

Simple Technique to Place the Lateral Mass Screws in the Revision Surgery after Cervical Laminoplasty for Ossification of the Posterior Longitudinal Ligament.

A lateral mass screw (LMS) is one of the standard anchor screws in posterior cervical fixation. Although the advantage of cervical LMS is that it is easier and safer to place than pedicle screw, it is sometimes difficult for surgeons to confirm the exact point for screw entry and accurate angle in cases of revision surgery. When LMS fixation is performed as revision surgery after cervical laminoplasty or laminectomy, it might be complicated to secure safe placement of the LMSs. We present a simple but practical technique involving a caliper and angle device for revision surgery after cervical laminoplasty for ossification of the posterior longitudinal ligament. In this technique, the distance between the bilateral entry points is ascertained using preoperative CT. Insertion of the screw is guided using the angle device set to 25 degrees. The technique presented here is easy and allows accurate placement of the LMSs in the posterior cervical spine, and is practical even for revision surgery.

C-Arm-Free Minimally Invasive Cervical Pedicle Screw Fixation (MICEPS): A Technical Note.

A minimally invasive posterolateral approach designed to avoid the lateral misplacement of midcervical pedicle screws was reported, but there is no technical report that describes this technique without C-arm fluoroscopy. We report the results of a 2.5 years follow-up of a 62-year-old female patient with C4 metastatic breast cancer. The patient suffered from severe neck pain and impending quadriplegia for 2 months after radiation therapy. We performed C-arm-free minimally invasive cervical pedicle screw fixation (MICEPS). The patient was suc-cessfully treated with surgery, and her neck pain was well controlled. She had neither neurological deficits nor neck pain at the final (2.5-year) follow-up. C-arm-free MICEPS is a useful technique; in addition, the sur-geons and staff have no risk of radiation exposure, there is a reduced need for postoperative imaging, and a decreased revision rate can be expected with C-arm-free MICEPS.

The accuracy of a novel pedicle screw insertion technique assisted by a special angular scale in the subaxial cervical spine using lateral mass as a reference marker

BackgroundPosterior cervical pedicle screw (CPS) internal fixation has better biomechanical stability than other posterior cervical fixation methods. However, this technique is limited in clinical practice due to the complex anatomical structure and the adjacent relationship of the cervical pedicle, and the high risk of neurovascular injury. The purpose of this study was to describe a novel subaxial CPS insertion technique assisted by a special angular scale using lateral mass as a reference marker and to evaluate the accuracy of CPS placement and the distribution characteristics of CPS misplacement.MethodsA total of 36 patients with subaxial cervical spine diseases who underwent posterior CPS fixation were consecutively selected. The optimal entry point on the posterior surface of the lateral mass was identified on the three-dimensional cervical model reconstructed from preoperative computed tomography (CT) images. The pedicle transverse angle (PTA) and pedicle-lateral mass angle (PLMA) were measured on the transverse and sagittal CT images respectively. The pedicle screws were inserted according to the preoperatively planned entry point and angles. We analysed the postoperative CT images for CPS misplacement rates and perforation directions following the Lee classification.ResultsOverall, 177 pedicle screws were inserted, of which 119 (67.2%) were classified as grade 0, 43 (24.3%) as grade 1, 12 (6.8%) as grade 2 and 3 (1.7%) as grade 3 by the postoperative CT images. The accuracy rate of CPS placement was 91.5%. Of the 15 misplaced pedicle screws (grades 2 and 3), 11 were lateral pedicle perforations, 3 were superior perforations and 1 was an inferior perforation. There were no neurovascular injuries related to CPS misplacement.ConclusionsWith our technique, the optimal entry point and two angles (PTA and PLMA) were identified for CPS insertion. The novel CPS insertion technique assisted by a special angular scale provides high accuracy and few complications.

Cervical fixation in the elderly

Posterior fixation of the cervical spine is a common procedure performed for many conditions including trauma, degenerative conditions, deformities, infection, neoplasms, and congenital malformations. Unlike thoracolumbar spine fixation, cervical fixation should consider the risk of vertebral artery injury in addition to the stability of the fixation and spinal cord/nerve root injury. Although lateral mass screw fixation is the most common type of cervical fixation, other options including pedicle screws and translaminar screws could be utilized. Each technique comes with its own advantages and risk of complications to the neural structures, vertebral artery, and fixation failure. However, these risks can be elevated in the elderly population with 1) decreased bone density 2) degenerative changes to the spine and 3) tortuosity of vertebral artery.

Usefulness of ipsilateral translaminar C2 screws insertion for cervical fixation in children with a low laminar profile: a technical note.

The fusion of the upper cervical spine in children is demanding due to its reduced size, its anatomical complexity, or a severe pathology of the cranio-cervical junction. In some pediatric patients with today's more popular C1-C2 or, occipito-C2 techniques, it is impossible, or very risky to perform a short upper cervical fixation. We present the utility and good results of ipsilateral laminar C2 screws insertion technique in two pediatric cases with low C2 laminar profile. Case 1: a 5-year-old child with a C1-C2 unstable subluxation, and a condylar assimilation of C1, where we performed an occipito-C2 fixation using an occipital plate and this modified translaminar C2 screw technique. Case 2: a 8-year-old Down syndrome boy who suffered an unstable subluxation of C1-C2 upon whom we performed a C1-C2 screw fixation using the same technique. Both cases have been followed up over a period of 7 and 2 years respectively, with good clinical results. We describe the technique and the feasibility of the ipsilateral insertion of translaminar C2 screws in children with low laminar profiles, as a good alternative to other techniques when the anatomy of the C2 does not permit its use or make them very risky.

A new concept of motion preservation surgery of the cervical spine: PEEK rods for the posterior cervical region.

Laminectomy may cause kyphotic postoperative deformity in the cervical region leading to segmental instability over time. Laminoplasty may be an alternative procedure to laminectomy, as it protects the spine against post-laminectomy kyphosis; however, similar to laminectomy, laminoplasty may cause sagittal plane deformities by destructing or weakening the dorsal tension band. Using finite element analysis (FE), we attempted to determine whether a posterior motion preservation system (PEEK posterior rod system concept) could overcome the postoperative complications of laminectomy and laminoplasty and eliminate the side effects of rigid posterior stabilization in the cervical region. We compared PEEK rods in four different diameters with a titanium rod for posterior cervical fixation. The present study may lead to motion preservation systems of the cervical vertebra. When PEEK rod is compared with titanium rod, considerable increase in range of motion is observed. PEEK rod-lateral mass screw instrumentation systems may be useful in motion preservation surgery of the posterior cervical region.

A Novel Reconstruction Using a Combined Anterior and Posterior Approach After Axis Tumor Spondylectomy.

This was a retrospective study. To describe a novel reconstruction strategy using a T-shaped titanium mesh cage with posterior cervical screw-rod fixation after total spondylectomy of axis tumors. Instability of the upper cervical spine because of tumors in axis (C2) often results in devastating complications. Surgical resection and reconstruction after spondylectomy of C2 remain a technical challenge because of the intricate anatomies, vital adjacent tissues, and the unique spinal biomechanics in this special region. The novel reconstruction mode included the construction of the anterior aspect conducted with a specially made titanium mesh cage and the posterior cervical fixation only. Patients who received total C2 tumors spondylectomy and reconstruction with this novel mode in our center between January 2009 and December 2017 were retrospectively analyzed to evaluate the efficacy of this novel reconstruction method. A total of 24 patients with C2 tumor received total spondylectomy and the new mode of local reconstruction. The neurological deficits recovered well and local pain relieved significantly (P<0.001) during the mean follow-up time of 22 months. Perioperative complications were rare and controllable. No internal fixation failure occurred. The mobility of the occipital-cervical junction was largely preserved in all patients. This novel reconstruction mode using an anterior "T-shaped" mesh cage with posterior screw-rod fixation provides satisfactory stability and motion of occipital-cervical junction with limited complications, and therefore may prove to be an ideal option for management of C2 tumors. Level IV.

Recurrent dysphagia after lower posterior cervical fusion

Background: Although dysphagia following posterior craniocervical fixation is well known, the incidence after mid-lower posterior cervical fixation is not well described. Here, we presented a case of recurrent dysphagia in a 72-year-old male following C3–T3 posterior cervical fixation and discussed its etiology.Case Description: A 72-year-old male sustained a cervical fracture in a fall; he was neurologically intact. The cervical/thoracic MR and CT studies documented ankylosing spondylitic changes in the cervicothoracic spine, a C5/6 disc herniation, and a C7 vertebral fracture. He underwent posterior cervical C3 to T3 fusion without decompression. For the 1st postoperative day, he complained of dysphagia without hoarseness, and fiberoptic endoscopy revealed poor esophageal mobility. For the next 6 postoperative years, he continued to require repeated attempts at the dilation of the esophageal entrance but remained reliant on a feeding tube.Conclusion: Posterior cervical fixation restricts cervical motion and may restrict expansion of the esophageal duct leading to permanent postoperative dysphagia requiring continued feeding tube utilization.

Fixed in the neck or pushed back into the thorax?-Impact of cervical anastomosis position on anastomosis healing.

BackgroundCervical anastomotic leakage remains a great challenge for thoracic surgeons in the surgical treatment of esophageal cancer. Among the factors affecting cervical anastomosis healing, the surgical technique is the key controllable element. This study aimed to identify the risk factors of cervical anastomotic leakage after McKeown esophagectomy, especially those controllable surgical factors.MethodsA retrospective review of patients who underwent McKeown esophagectomy in the past eight years in West China Hospital was performed. Patients with cervical anastomotic leakage were assigned to leakage group (LG) while the left was enrolled in the none-leakage group (NLG). Multivariate logistic regression analysis was used to identify independent risk factors of anastomotic leakage.ResultsA total of 518 patients were enrolled in the final analysis. In the baseline comparison, the difference in fixation of anastomosis in the neck, anastomosis mode, diabetes, and hypertension between the LG and NLG reached statistically significant. Moreover, the statistical difference of cervical fixation, anastomosis mode, and hypertension remained significant in the multivariate logistic regression analysis.ConclusionsThe cervical anastomosis fixation, anastomosis mode, and hypertension are independent risk factors of gastroesophageal cervical anastomotic leakage.

The Utility of Cervical Spine Bracing As a Postoperative Adjunct to Multilevel Anterior Cervical Spine Surgery.

Use of cervical bracing/collar subsequent to anterior cervical spine discectomy and fusion (ACDF) is variable. Outcomes data regarding bracing after ACDF are limited. Here, we study the impact of bracing on short-term outcomes related to safety, quality of care, and direct costs in multilevel ACDF. Retrospective cohort analyses of all consecutive patients undergoing multilevel ACDF with or without bracing from 2013 to 2017 was undertaken (n = 616). Patient demographics and comorbidities were analyzed. Tests of independence and logistic regressions were used to assess differences in length of stay (LOS), discharge disposition (home, assisted rehabilitation facility [ARF], or skilled nursing facility [SNF]), quality-adjusted life year (QALY), direct cost, readmission within 30 days, and emergency room (ER) visits within 30 days. Amongst the study population, 553 were braced and 63 were not braced. There was no difference in comorbidities (P > .05) such as obesity, smoking, chronic obstructive pulmonary disease, hypertension, coronary artery disease, congestive heart failure, and problem list number. A significant difference in American Society of Anesthesiologists (ASA) score was found, with more ASA 2 patients in the braced cohort and more ASA 3 patients in the unbraced cohort (P = .007). LOS was extended for the unbraced group (median 156.9 ± 211.4 versus 86.67 ± 130.6 h, P = .003), and ER visits within 30 days were 0.21 times less likely in the braced group (P = .006). There was no difference in readmission (P = .181), QALY gain (P = .968), and direct costs (P = .689). Bracing following multilevel cervical fixation does not alter short-term postoperative course or reduce the risk for early adverse outcomes in a significant manner.

Classification and Surgical Treatment of Developmental Spinal Canal Stenosis at Atlas Level: A 15-Case Study.

A retrospective study. Investigate the diagnosis and surgery strategy for treatment of development spinal canal stenosis (DSSA) at atlas plane based on computerized tography (CT) image characters. The occurrence of spinal canal stenosis in the atlas plane is relatively rare compared with lower cervical. Fifteen patients diagnosed with DSSA were included from 2014 to 2018. They are divided into four subgroups based on the character of CT images: group I (small size atlas), group II (hypertrophy of posterior arch of the atlas [PAA]), group III (incurved of PAA), and group IV (hypertrophy odontoid). There are type I 7, type II 3, type III 2, and group IV 3 in the 15 cases. All the patients received different surgery procedures respectively: (1) posterior arch osteotomy were performed for group I/III//IV without atlantoaxial dislocation, (2) posterior arch resect and replantation were performed for group II, (3) occipital cervical fixation and fusion were added to the patients with associated atlantoaxial dislocation (AAD), (4) a new method of odontoid reduce and atlantoaxial fixation by transoral approach were performed for group IV with associated AAD. All cases underwent surgery successfully which included posterior occipitocervical fixation (OCF) + posterior arch resection (PAR) eight cases, PAR four cases, posterior arch remodeling and re-implantation (PARR) two cases, and Dens remodeling + trans-oral anterior reduction and plate fixation (DR+TARP) one case without severe complications. All patients show different improvement in the symptoms. Japanese orthopaedic association score improved from 9.2 to 14.7 in 1 year follow-up. DSSA could be easily diagnosed and divided into four subgroups according to the character of CT image, corresponding surgery strategy could receive a fine clinical result.Level of Evidence: 4.