Results of Surgical Fixation of Occipitocervical Instability Using Polyaxial Plate/Rod System. Report of 14 Cases (original) (raw)
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Occipitocervical Fixation: Long-Term Results
Spine, 2005
The study is a retrospective review of 58 patients who underwent occipitocervical fusion between 1997 and 2001. Objectives. Our objective is to study the clinical results after occipitocervical fixation with long-term follow-up and assess factors contributing to clinical success. Methods. Data from patient charts, operative notes, physician office notes, and imaging studies were incorporated in the study. Myelopathy was assessed using a Nurick scale for preoperative and postoperative evaluation. Fusion was assessed using cervical plane films with flexion and extension views. Results. Mean follow-up was 36 months, with all patients having a greater than 1-year follow-up. The most common pathology was congenital cranial settling (41%) followed by trauma (22%) and rheumatoid arthritis (17%). Myelopathy was the most common presentation (62%) followed by pain (28%). A successful fusion occurred in 48 out of 51 patients (94%). Symptoms improved in 86% of patients, whereas 35% improved 1 Nurick grade. Complications occurred in 30% of patients. The cervical wound infection rate was 5%. The rate of adjacent level degeneration was 7%. The mortality rate was 1.7%. Conclusions. Occipitocervical instrumentation allows for very high fusion rates without the need for halo vest immobilization. All patients with successful fixation have pain resolution. Myelopathy improves in most patients, whereas one-third of patients demonstrate dramatic improvement.
Use of Screw-Rod System in Occipitocervical Fixation
Journal of the Chinese Medical Association, 2009
Background: This study retrospectively reviewed 9 patients who underwent occipitocervical fixation with a newly developed screw-rod fixation system between April 2004 and November 2005. The objective was to evaluate the clinical result of occipitocervical fixation with the screw-rod fixation system, including symptom relief, fusion rate and complications. Methods: All 9 patients received occipitocervical fixation surgery with screw-rod fixation system and autologous bone grafts for fusion. Fusion was assessed by plain cervical X-ray films, and the myelopathy by Nurick scale. Results: Four males and 5 females were enrolled into this study. Mean age was 58.8 years, and mean follow-up period was 15 months. One female patient experienced surgical site infection with instrument pullout 20 months after surgery; she received a second operation for instrument revision. The overall fusion rate was 100%. The mean Nurick scores were 3 preoperatively and 2.1 postoperatively, with advancement of 0.9 points on average. Seven of 9 patients experienced pain or myelopathy improvement. There were no complications except for the 1 infection mentioned above. Conclusion: The fusion rate, complication rate and improvement in neurological function of occipitocervical fixation surgery using the screw-rod system were comparable to those of the widely used wire-rod system and screw-plate system.
Occipitocervical fusion via occipital condylar fixation: a clinical case series
Journal of spinal disorders & techniques, 2014
Retrospective review/case series. This study aims to present the clinical feasibility of condylar fixation in occipitocervical (OC) fusion. Here, we present the largest clinical series to date of patients who underwent OC fusion via cervicocondylar fixation using a polyaxial screw/rod construct. The novel technique using the occipital condyles as the sole cranial fixation point has been described. Both cadaveric and biomechanical studies, in recent literature, have shown technical feasibility and surgical safety of condylar fixation. We retrospectively reviewed a prospectively acquired database of all patients treated with OC fusion via cervicocondylar fixation at our institution between 2007 and 2011. All patients were scheduled for follow-up postoperatively at weeks 2, 6, 12, 24, and annually thereafter. Outcome measures included estimated blood loss, operative time, complications, integrity of the construct, and fusion rates. Exclusion criteria included condylar fracture, previou...
Clinical Biomechanics, 2020
Background: Occipito-cervical fusion can be necessary in case of cranio-cervical junction instability. Proximal stabilisation is usually ensured by bi-cortical occipital screws implanted through one median or two lateral occipital plate(s). Bone thickness variability as well as the proximity of vasculo-nervous elements can induce substantial morbidity. The choice of site and implant type remains difficult for surgeons and is often empirically based. Given this challenge, implants with smaller pitch to increase bone interfacing are being developed, as is a surgical technique consisting in inverted occipital hook clamps, a potential alternative to plate/screws association. We present here a biomechanical comparison of the different occipito-cervical fusion devices. Methods: We have developed a 3D mark tracking technique to measure experimental mechanical data on implants and occipital bone. Biomechanical tests were performed to study the mechanical stiffness of the occipitocervical instrumentation on human skulls. Four occipital implant systems were analysed: lateral plates+large pitch screws, lateral plates+hooks, lateral plates+small pitch screws and median plate+small pitch screws. Mechanical responses were analysed using 3D displacement field measurements from optical methods and compared with an analytical model. Findings: Paradoxical mechanical responses were observed among the four types of fixations. Lateral plates +small pitch screws appear to show the best accordance of displacement field between bone/implant/system interface providing higher stiffness and an average maximum moment around 50 N.m before fracture. Interpretation: Stability of occipito-cervical fixation depends not only on the site of screws implantation and occipital bone thickness but is also directly influenced by the type of occipital implant.
Surgical outcome of Occipitocervical Fixation for Craniocervical Instability
Journal of Saidu Medical College, Swat, 2022
Background: The occipitocervical junction is a unique area between the cranium and the upper cervical spine. Treating pathologies of this region require a good knowledge and understanding of the anatomy, biomechanics of this region and nature of the disease. Objective: To evaluate the efficacy of Occipitocervical Fixation (OCF) in patients with craniocervical instability in two tertiary care hospitals. Metrial and Methods: This study was conducted at Combined Military Hospital Rawalpindi and Hayatabad Medical Complex, Peshawar from April 2005 to December 2016. All patients with craniocervical instability were included in our study, and those having occipital bone fractures or previously operated patients with same technique were excluded from this study. The patients were compared using lateral static and dynamic X-ray taken before the operation, after the operation, and during last follow-up. The Nurick score was used to assess neurological function pre and postoperatively. Results...
Biomechanical evaluation of occipitocervicothoracic fusion: impact of partial or sequential fixation
The spine journal : official journal of the North American Spine Society
Surgical instrumentation used for posterior craniocervical instability has evolved from simple wiring techniques to sophisticated implant systems that incorporate multiple means of rigid fixation for the cervical spine. Polyaxial screws and lamina hooks in conjunction with occipital plating and transitional rods for caudal fixation theoretically allow for fixation points at each vertebra along the posterior aspect of the cervical spine. However, the potential for anatomical constraints to prevent intraoperative instrumentation at the desired vertebral level exists. The biomechanical implications of such "skipped segments" have not been well documented. The purpose of this study was to determine the biomechanical effects of partial three-point fixation versus sequential fixation at all levels of the cervical spine from the occiput to T1. Fresh frozen human cadaveric cervical spines from the occiput (CO) to T1 were prepared and mounted on a spine simulator. Motion was assess...
Occipitocervical Fusion Surgery: Review of Operative Techniques and Results
Journal of Neurological Surgery Part B: Skull Base, 2015
Objective Varying types of clinicoradiologic presentations at the craniovertebral junction (CVJ) influence the decision process for occipitocervical fusion (OCF) surgery. We discuss the operative techniques and decision-making process in OCF surgery based on our clinical experience and a literature review. Material and Methods A total of 49 consecutive patients who underwent OCF participated in the study. Sagittal computed tomography images were used to illustrate and measure radiologic parameters. We measured Wackenheim clivus baseline (WCB), clivus-canal angle (CCA), atlantodental distance (ADD), and Powers ratio (PR) in all the patients. Results Clinical improvement on Nurick grading was recorded in 36 patients. Patients with better preoperative status (Nurick grades 1-3) had better functional outcomes after the surgery (p ¼ 0.077). Restoration of WCB, CCA, ADD, and PR parameters following the surgery was noted in 39.2%, 34.6%, 77.4%, and 63.3% of the patients, respectively. Complications included deep wound infections (n ¼ 2), pseudoarthrosis (n ¼ 2), and deaths (n ¼ 4). Conclusion Conventional wire-based constructs are superseded by more rigid screwbased designs. Odontoidectomy is associated with a high incidence of perioperative complications. The advent of newer implants and reduction techniques around the CVJ has obviated the need for this procedure in most patients.
The cervical end of an occipitocervical fusion: a biomechanical evaluation of 3 constructs
Journal of Neurosurgery: Spine, 2008
Object Stabilization with rigid screw/rod fixation is the treatment of choice for craniocervical disorders requiring operative stabilization. The authors compare the relative immediate stiffness for occipital plate fixation in concordance with transarticular screw fixation (TASF), C-1 lateral mass and C-2 pars screw (C1L-C2P), and C-1 lateral mass and C-2 laminar screw (C1L-C2L) constructs, with and without a cross-link. Methods Ten intact human cadaveric spines (Oc–C4) were prepared and mounted in a 7-axis spine simulator. Each specimen was precycled and then tested in the intact state for flexion/extension, lateral bending, and axial rotation. Motion was tracked using the OptoTRAK 3D tracking system. The specimens were then destabilized and instrumented with an occipital plate and TASF. The spine was tested with and without the addition of a cross-link. The C1L-C2P and C1L-C2L constructs were similarly tested. Results All constructs demonstrated a significant increase in stiffness...
BACKGROUND CONTEXT: Although there are many techniques for occipitocervical fixation, there have been no reports regarding occipitocervical fixation via the use of an anterior anatomical locking plate system. PURPOSE: The biomechanics of this new system were analyzed by a three-dimensional finite element to provide a theoretical basis for clinical application. STUDY DESIGN: This was a modeling study. PATIENT SAMPLE: We studied a 27-year-old healthy male volunteer in whom cervical disease was excluded via X-ray examination. OUTCOME MEASURES: The states of stress and strain of these two internal fixation devices were analyzed. METHODS: A three-dimensional finite element model of normal occiput-C2 was established based on the anatomical data from a Chinese population. An unstable model of occipital-cervical region was established by subtracting several unit structures from the normal model. An anterior occiput-to-axis locking titanium plate system was then applied and an anterior occiput-to-axis screw fixation was performed on the unstable model. Limitation of motion was performed on the surface of the fixed model, and physiological loads were imposed on the surface of the skull base. RESULTS: Under various loads from different directions, the peak values of displacement of the anterior occiput-to-axis locking titanium plate system decreased 15.5%, 12.5%, 14.4%, and 23.7%, respectively, under the loads of flexion, extension, lateral bending, and axial rotation. Compared with the anterior occiput-to-axis screw fixation, the peak values of stress of the anterior occiputto-axis locking titanium plate system also decreased 3.9%, 2.9%, 9.7%, and 7.2%, respectively, under the loads of flexion, extension, lateral bending, and axial rotation. CONCLUSION: The anterior occiput-to-axis locking titanium plate system proved superior to the anterior occiput-to-axis screw system both in the stress distribution and fixation stability based on finite element analysis. It provides a new clinical option for anterior occipitocervical fixation. Ó
Neurology India, 2007
The osseous articulations and their supporting ligaments must resist forces in all axes of motion. [1-5] Various pathological conditions can destabilize this junction. The surgical goal, therefore, is relief of neural compression and stabilization. [6-9] Occipitocervical fusion was first described by Forrester in 1927. [9] All internal fusion techniques focus on providing rigid constructs to facilitate bony fusion and reduce the need for and the duration of external immobilization. [2,3,5,7,9-11] The various techniques of posterior stabilization of CVJ are classified into those that use 1) Methylmethacrylate; 2) Occipitocervical plates and screws; 3) Contoured rod (CR) with wires; 4) Metallic clamps; and, 5) Transarticular screws. Autologous bone graft promotes a good bony union. The long-term stabilization depends on bony integration. [10-20] The Ransford's occipitocervical CR fusion method first reported in 1986 has stood the test of time as an effective and economical method of posterior stabilization. [19] The technique involves fixing a prefabricated loupe to the occiput and the upper cervical laminae using sublaminar wires. [6,8,9] The first description of the technique in India was by Das et al. [12] The basic method has remained constant albeit with minor modifications including threaded pins, interspinous wiring, shape variations and the use of magnetically inert materials. [9,11,14,20,21] Despite the emergence of several new occipitocervical fusion techniques, [8-10,15,17,22,23] CR fusion is still one of most economical and versatile methods that is especially useful in certain specific situations. This study focuses on the indications, outcome, advantages and drawbacks in using CR fusion.