Cervical interbody stand-alone cage
A cervical interbody stand-alone cage, often referred to as a cervical interbody cage or simply a cervical cage, is a medical device used in spinal surgery to treat conditions of the cervical spine (neck region). It is designed to be inserted between two adjacent cervical vertebrae to provide stability and promote fusion. Here's some essential information about cervical interbody stand-alone cages:
Purpose
Cervical cages are used to treat various cervical spine conditions, including cervical degenerative disc disease, cervical disc herniation, cervical spinal stenosis, and cervical degenerative spondylolisthesis. The cage's primary purpose is to restore the space between vertebrae, maintain proper alignment, and promote fusion of the adjacent vertebrae.
Material
These cages are typically made of biocompatible materials like titanium or polyetheretherketone (PEEK). These materials are chosen for their strength, compatibility with the body, and ability to integrate with the surrounding bone.
Design
Cervical cages come in various shapes and sizes, but they are generally designed to fit snugly between the vertebral bodies. Some common cage designs include rectangular, cylindrical, and wedge-shaped cages. The choice of design depends on the surgeon's preference and the patient's specific spinal condition.
Fusion Promotion
Cervical cages are often used in conjunction with bone graft material. A bone graft can be placed within the cage or around it. This promotes the fusion of the adjacent vertebrae over time, effectively stabilizing the spine.
Stand-Alone Feature
The term “stand-alone” implies that these cages can provide stability and promote fusion without the need for additional hardware such as plates or screws. However, in some cases, supplemental fixation may still be required to ensure proper stability and alignment.
Surgical Procedure
The surgical procedure to insert a cervical interbody cage
see Anterior cervical discectomy.
Bone graft material may be added before or after placing the cage. The incision is then closed, and the patient is monitored during the healing process.
Post-Operative Care
Patients who undergo cervical spine surgery with interbody cages often need a period of post-operative rehabilitation and may be required to wear a cervical collar for support. The fusion process can take several months, and the patient's progress is monitored through follow-up appointments and imaging studies.
Cervical interbody stand-alone cages are just one of the many tools available to orthopedics and neurosurgeons for addressing cervical spine issues. The choice of surgical approach and implant depends on the patient's specific condition and the surgeon's assessment of the best treatment plan.
Classification
Cervical interbody Zero-profile stand-alone cage.
Cervical interbody stand-alone cage and anterior cervical plate.
Materials
Graft (e.g. PEEK, cadaver bone, titanium cage…) and anterior cervical plate (optional, especially on single-level ACDF).
Autologous bone (usually from the iliac crest), non-autologous bone (cadaveric), bone substitutes (e.g. hydroxylapatite 1)) or synthetics (e.g. PEEK or titanium cage) filled with an osteogenic material. Substitutes for autologous bone eliminate problems with the donor site but may have a higher rate of absorption. There were also cases of HIV transmission from cadaveric bone grafts in 1985, however, as a result of the heightened awareness of AIDS since that time together with significant improvements in antibody testing and careful screening of donors, no further cases have been reported.
Different interbody cages are currently used for surgical reconstruction of the anterior and middle columns of the spine following anterior cervical corpectomy. However, subsidence and delayed union/nonunion associated with allograft and cage reconstruction are common complications, which may require revision with instrumentation.
Cages come in different shapes and sizes; some are cylinder-shaped and others box-shaped. Cages are placed (fit) into the spine between vertebrae. Usually, cages are made from bone, metal, plastic, or carbon fiber. Bone chips (autograft, allograft, other bone graft substitutes, or other bone growth-stimulating substances (e.g., demineralized bone matrix) may be packed into the cage. During the months after surgery, the hope is the cage will allow (enhance) fusion between the vertebrae below and above. Fusion increases spinal stability.
Variations include the use of cervical cages made of several materials instead of autologous bone and the use of cages with or without cervical plating. The stand-alone cervical cages (SAc) have the advantages of less surgical time, less bleeding, and less cervical tissue dissection, with a lesser ratio of postoperative dysphagia and quicker recovery 2).
Devices
see https://thespinemarketgroup.com/category/acif/stand-alone/
Abudouaini et al. creatively designed an elastically deformable cervical implant to reduce the postoperative stress concentration.
They aimed to investigate the biomechanical performance of this novel cervical implant and compare it with the commonly used cervical devices.
A biomechanical test was conducted on twelve fresh-frozen human cadaveric cervical spines (C2-C7) and randomly divided into four groups according to implant types: the intact group, Cervical interbody zero-profile stand-alone cage (ACDF) group, the novel cervical implant group, and the Pretic-I artificial cervical disc (ACDR) group. An optical tracking system was used to evaluate the segmental range of motion (ROM) of the C4/C5, C5/C6, and C6/C7 segments, and a micro pressure sensor was used to record the maximum facet joint pressure (FJP), maximum intradiscal pressure (IDP) at the C4-5 and C6-7 segments.
There were no significant differences in the ROM of adjacent segments between the groups. Compared with the intact group, the ACDR group essentially retained the ROM of the operated segment. The novel cervical implant decreased some ROM of the operated segment, but it was still significantly higher than in the fusion group; The maximum FJP and IDP at the adjacent segments in the ACDF group were significantly higher than those values in the other groups, and there were no differences in the other groups. While the newly developed elastically deformable cervical implant does not completely maintain ROM like the artificial cervical disc, it surpasses the fusion device with regard to biomechanical attributes. After further refinement, this novel implant may be suitable for patients who are prone to severe adjacent segment degeneration after fusion surgery but no indication for artificial cervical disc surgery 3).
Idys®-C ZP 3DTi (Clariance Spine)
STALIF C FLX (Centinel Spine)
Hexanium ACIF cage (SpineVision)
Redmond Polymer Cervical Cage (A-Spine)
STALIF C-Ti™ (Centinel Spine)
AIS-C 3DP Stand-Alone Cervical Cage (Genesys Spine)
AIS-C Stand-Alone System (Genesys Spine)
PRORAY™ (PRODORTH)
PROYSTER® (PRODORTH)
Capri-Z (Tsunami Medical)
T-lock Cervical Stand-alone Cage (BAUI)
ACIFBOX Stand Alone Cervical Cage
Alta System
Align SA-C
ACIFBOX Cervical Cage with Blade
Aero-C
ARION Expandable Bladed Cervical Cage
Arcadius ®XP C Spinal System
AVS® Anchor-C Cervical Cage
Autoblock Anterior Cervical Cage
A-CIFT™
SoloFuse™
Blackhawk™Cervical Spacer ChoiceSpine
Blackhawk™ Ti Cervical Spacer ChoiceSpine
CoRoent® Small Interlock™
COALITION
ClariVy Cervical IBF System
C-Fix Peek
Cedix-P Spacer
COALITION MIS® SintrOS™
Crea STAND-ALONE CERVICAL PEEK CAGE
COALITION MIS™
CHESAPEAKE® Cervical-Ti Stabilization System
CAVUX Cervical Cage-L SA System
C2C Cervical Titanium Spine System
Ceres-C Stand-alone
Cavetto- SA™ Ti
C-CURVE™
Dakota ACDF™ System
Dolomite ACSS System
Divergence
Emminent Spine Cervical Cage
Endoskeleton® TCS
HiJAK AC
Hive™ Standalone Cervical System
HRCC®
HEDRON IC™
Intervertebral cervical locking cage
F3D C2 Stand Alone Cervical
Irix-C™
InterPlate™ IFD
IN:C2 Cervical Cage
Kentro SELF Standalone Cervical cage
LorX ACIF Peek Cage
L-ACIF
LONESTAR® Cervical Stand Alone
Monza
Miraclus ACC
Mecta-C Stand Alone Interbody Fusion
Monet™ Anterior Cervical Fusion system
MINERVA
NEXXT MATRIXX® Stand Alone Cervical System
Optio-C® Anterior Cervical System
OVERFIX Cervical Cage
ONIX
Paramount® Anterior Cervical Cage
Pegasus Anchored Cervical Interbody
Pallas Low Profile Anterior Cervical Cage
PRO-LINK Ti Titanium Stand-Alone Cervical Spacer System
Pro-less Cage
PRO-LINK Stand-Alone cervical spacer
PL-AGE® Anterior Cervical Fusion System
PEEK Prevail®
ReConnect Cage
ROI-C
Rig®-ZP (Zero Profile Cervical cage)
Romero Self-Anchored Cervical Cage
Red Ruby ACI
SPIRA- C Integrated Interbody system
STACC
SABER C™ Cervical Fusion System
SCARLET®AC-T
SKATE, Cervical Plate Kit
SPICCA-SP
Solitaire™-C Cervical
Shoreline RT®
Siluette
Shoreline® ACS
Tesera SC Stand-alone
TRUSS CSTS-SA
TOMCAT™ Cervical Spinal System
Titanopeek-C Stand Alone
Vertu® Cervical Implant System
Unicorn CS
VariLift®-C
Vault C Anterior Cervical
Velofix™ SA Cervical Cage
Veyron-C System
Walnut
X-Zone System
ZERO-P™ VA Stand Alone Spacer
ZERO-PZ-LINK™ Cervical
Zero-Profile Anterior Cervical Intervertebral Locking Plate And Cage Combination System
see Cespace xp
Stabilis Stand Alone Cage
Bagby and Kuslich (BAK) device.
Variations include the use of cervical cages made of several materials instead of autologous bone and the use of cages with or without cervical plating. The stand-alone cervical cages (SAc) have the advantages of less surgical time, less bleeding, and less cervical tissue dissection, with a lesser ratio of postoperative dysphagia and quicker recovery 4).
HA, coralline HA, sandwiched HA, TCP, and biphasic calcium phosphate ceramics were used in combination with osteoinductive materials such as bone marrow aspirate and various cages composed of poly-ether-ether-ketone (PEEK), fiber carbon, and titanium. Stand-alone ceramic spacers have been associated with fracture and cracks. Metallic cages such as titanium endure the risk of subsidence and migration. PEEK cages in combination with ceramics were shown to be a suitable substitute for autograft.
None of the discussed options has demonstrated clear superiority over others, although direct comparisons are often difficult due to discrepancies in data collection and study methodologies. Future randomized clinical trials are warranted before definitive conclusions can be drawn 5).
There has been an increase in the use of standalone cage devices due to ease of use and studies suggesting a lower rate of acute post-operative dysphagia.
Stand-alone cervical cages aim to provide primary stability, yield solid fusion in the long-term course, and maintain physiologic alignment. However, many implants designed for these purposes fail in achieving these goals.
There is evidence documenting relatively frequent complications in stand-alone cage assisted anterior cervical discectomy and fusion (ACDF), such as cage subsidence and cervical kyphosis 6).
Failure of disc height maintenance may lead to cervical kyphosis and poor alignment of the cervical spine. At the same time, costs for cage implantation are relatively high compared with their unfavorable radiologic performance.
Brenke et al, develop and test mechanically a low-cost polymethylmethacrylate (PMMA) cage with similar mechanical and procedural properties compared with a commercial polyetheretherketone (PEEK) cage.
Following determination of the cage design, a casting mold was developed for the production of PMMA cages. Nine cages were produced and compared with nine PEEK cages using static compression tests for 0 and 45 degrees according to the recommendations of the American Society for Testing and Materials. Mean compressive yield strength, mean yield displacement, mean tensile strength, and mean stiffness were determined. Results At 0 degrees axial compression, the mean compressive yield strength, mean displacement, and mean tensile strength of the PMMA cage was significantly higher compared with the PEEK cage (p < 0.001). Stiffness of both implants did not differ significantly (p = 0.903). At 45 degrees axial compression, PEEK cages could not be investigated because slipping of the holding fixture occurred. Under these conditions, PMMA cages showed a mean compressive yield strength of 804.9 ± 60.5 N, a mean displacement of 0.66 mm ± 0.05 mm, a mean tensile strength of 7.92 ± 0.6 N/mm2, and a mean stiffness of 1,228 ± 79.4 N/mm.
The developed PMMA cage seems to show similar to superior mechanical properties compared with the commercial PEEK cage. Considering a preparation time of only 10 minutes and the low price for the PMMA material, the cost-benefit ratio clearly points to the use of the PMMA cage. However, clinical effectiveness has to be proven in a separate study 7).