Spinal stabilization systems

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Over the past decades, spine surgery has made a huge breakthrough in its development, thanks to the development and implementation of various approaches - ventral, dorsal, anterolateral, combined; anesthesiology and resuscitation, which allow patients to withstand many hours of traumatic operations with significant blood loss and, of course, the constant improvement of stabilizing systems.

In this short review of our own experience in treating spinal diseases, I would like to pay special attention to modern designs for stabilizing the spine, highlighting the strengths and weaknesses , and demonstrating various combinations of implants in a given clinical situation. The medical market for implants in our country is rapidly developing; new designs presented by various manufacturers are entering the arena, which is due to technological progress, competition and a huge commercial component.

Traditionally, Western European and American manufacturers are in the lead , but increasingly Asian implants made in China, South Korea, etc. are coming into our daily practice.

The very first vertebral body replacement prosthesis was one's own bone (auto-bone from the iliac crest, a section of a rib, or a fibula), which was installed between the vertebral bodies in special grooves instead of the removed one. Additional fixation was not performed, and therefore the risk of autologous bone migration remained, and the patient was forced to observe long-term bed rest until reliable bone fusion was formed. This significantly reduced the patient’s quality of life and was associated with hypodynamic complications. Over time, devices were developed that promoted immobilization of the bone graft so that the patient could be activated in the early postoperative period. Until now, own bone is considered the “golden” standard in creating corporedesis.

Clinical example

CT scans of the patient before and after surgical treatment for a complicated fracture of the fifth cervical vertebra are presented. A corpectomy of the fifth cervical vertebra was performed with combined corpodesis using autologous bone from the iliac crest and a plate made in China. An increasing number of clinics are mastering the technique of “anterior interventions on the thoracic and lumbar spine,” which also uses autologous bone for interbody corporedesis.

Features and types of cervical spine implants

Designs specially designed for implantation into the cervical spine accurately replicate the anatomy of the vertebrae of this spine and are capable of reliably stabilizing it. Today they are presented in a fairly wide variety, which allows the spinal surgeon to choose the device that will most fully solve the assigned problems.

Among the most popular implants for the cervical spine:

titanium mesh mesh;
body replacement telescopic implant ADD plus;
stabilizing cervical cage HRC Cervical;
cervical intervertebral disc endoprosthesis M6-C.

In the cervical spine, disorders most often occur as a result of injuries, especially road accidents, which often leads to the need for surgery and installation of an implant.

When undergoing cervical spine prosthetics, the patient is recommended to stay in the hospital for no more than 2–3 days. But after this, it is important to undergo full rehabilitation so that the implanted structure takes root reliably. The recovery period after neurosurgical operations on the cervical spine takes an average of 2 months.

Titanium Mesh

The implant is a thin-walled, hollow inside cylinder with a mesh structure. It is designed for installation between vertebral bodies to replace a removed intervertebral disc and is strengthened with a special support plate.

During the operation, the neurosurgeon places a fragment of the patient’s own bone inside the cylinder, which ensures gradual growth of bone tissue on the implant and reliable consolidation of the vertebrae with each other. As a result, they grow together, thereby forming a single bone conglomerate.

Body replacement telescopic implant ADD plus

Structurally, the implant is formed by a body-substituting cage and a plate. It is made of titanium and has distraction capabilities.

The body replacement telescopic implant ADD plus is used when it is not possible to restore the vertebral body, which provokes the need to remove it, for example, by corpectomy. It is installed in the vacant space between the preserved vertebral bodies. This allows you to maintain the normal height of the operated spine and reliably stabilize it.

Stabilizing cervical cage HRC Cervical

The implant is a trapezoidal washer with a large hole in the center. Its body is made of high-strength PEEK polymer material with an elastic modulus that fully matches the properties of cancellous and cortical bone tissue. It is used to replace a vertebra that has been removed for one reason or another.

A bone graft is placed into the cavity of the cage, which ensures high quality of its fusion with the vertebral bodies. The HRC Cervical implant does not require the use of screws or any additional plates, since it is equipped with a special titanium retainer. It is made in the form of a blade, which is located on one of the edges of the cage.

Thus, the cervical implant is mounted by cutting the fixator into the vertebral bone as it rotates. This ensures the reliability of its fixation between adjacent vertebrae and eliminates the risk of migration.

Cervical intervertebral disc endoprosthesis M6-C

One of the most modern and ergonomic implants for the cervical spine is an intervertebral disc endoprosthesis. It completely replicates the anatomy and biomechanics of the natural disc, which makes it possible to consider it as a full-fledged organ-substituting device.

The endoprosthesis is formed:

An artificial fibrous ring made of fibrous high molecular weight polyethylene. It is responsible for ensuring the natural range of motion of the intervertebral disc.
Synthetic nucleus pulposus, for the production of which a viscoelastic polymer is used. Its properties fully correspond to the natural nucleus pulposus, which guarantees correct axial compression.
Titanium-coated support platforms located on both horizontally oriented sides of the endoprosthesis. They have high strength and resistance to mechanical loads, which ensures the safety of the remaining components of the structure when the patient performs physical work.

Reliability of fixation of the prosthesis is achieved due to specially created ribs on the supporting platforms and their porosity. Thanks to this, osseointegration processes occur at high speed, and the structure quickly takes root.

Clinical example

These tomograms show an unstable fracture of the Tn12 vertebral body

The first stage was laminectomy with transpedicular fixation using a Chinese system, followed by corpectomy, corpodesis with autologous bone and a Chinese-made thoracolumbar plate.

Photo of transpedicular fixation of the spine

X-ray after surgery

Thus, the terms of rehabilitation depend on the disease for which surgery was performed, and the operation of transpedicular fixation helps to accelerate the rehabilitation process.
Author of the article: neurosurgeon Anton Viktorovich Vorobiev Frame around the text
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Clinical example

Patient with nonspecific spondylodiscitis in the thoracic spine

A thoracotomy, transpleural corpectomy, combined corporodesis with autologous bone and a Centaur plate from Stryker were performed.

As already mentioned, autologous bone is considered an ideal material and the “gold” standard for prosthetics of the vertebral body and creating a strong corporedesis, but this technique is not ideal and has a number of disadvantages: 1. Taking autologous bone is an independent additional operation, which lengthens the time of the main surgical intervention. 2. It is an additional weakening factor in weakened, elderly patients (including those with tumor lesions of the spine), and is an additional source of bleeding from a bone wound. 3. The operation of taking an autograft from the iliac crest in patients with a fracture of the pelvic bones is not always possible or convenient. 4. Resorption of the bone autograft is possible with the development of instability of the operated segment. All these arguments encourage the creation of artificial metal, ceramic, and other vertebral body substitutes.

Titanium mesh MESH is a common vertebral body substitute and is used for all areas of the spine. It is a section of tube of various diameters and lengths (depending on which part of the spine will be implanted) with diamond-shaped holes. Taking into account the height of the intervertebral space after corpectomy, the MES is modeled (cut to the required length), filled with its own bone or osteoinductive material and installed between the vertebral bodies. MES alone cannot provide rotational stability in the operated segment of the spine, and therefore requires additional fixation with an anterior or anterolateral plate and installation of a transpedicular system.

Rehabilitation

After surgery on the spine with the installation of a metal structure of one kind or another, it is very important to undergo a full course of rehabilitation so that the body can fully recover and the installed metal structure can take root. The recovery program is compiled individually for each patient, but is always aimed at:

activation of spinal nutrition;
acceleration of regeneration processes;
strengthening the muscle corset, which helps reduce the load on the spine when walking or physical work;
restoration of normal mobility.

On average, rehabilitation takes about six months, but a person remains disabled only for a maximum of 4 months, but often no more than 2 weeks. The patient receives sick leave for the entire duration of treatment. But the larger the area of fixation, the longer the recovery period will last.

During the entire rehabilitation period, it is necessary to strictly follow medical recommendations, since in 80% of cases complications and undesirable consequences are a direct consequence of underestimating the importance of rehabilitation. All patients are prescribed drug therapy, which may include:

broad-spectrum antibiotics;
painkillers;
corticosteroids;
anticoagulants;
muscle relaxants;
nootropics;
chondroprotectors.

After surgical treatment of segmental instability, the patient's activation begins as early as possible. This usually happens within 3–5 days. But if bone grafts were used simultaneously with the implantation of metal structures, the patient will be prescribed longer immobilization.

To reduce the load on the operated part of the spine and create the most favorable conditions for fusion of bone fragments, special orthopedic corsets or bandages are used.

Exercise therapy is also prescribed. The first physical therapy sessions are carried out under the supervision of a rehabilitation specialist, and in a lying position. Only over time is it possible to practice while standing. The doctor individually calculates the permissible load and selects the optimal exercises. Gradually, the duration and intensity of exercises increase, but any sudden movements, both during exercise and in everyday life, are contraindicated.

If pain occurs during independent exercise therapy, the exercise should be stopped immediately and consult a doctor.

Physiotherapy and massage therapy sessions are also provided as part of the rehabilitation program. This helps speed up regeneration processes and reduce the risk of muscle atrophy.

Without the permission of the attending physician you cannot:

lift objects heavier than 3 kg;
do twisting, bending;
run, jump;
perform sharp swings with arms or legs;
arch your back.

Clinical example

Patient with breast cancer metastasis in the first lumbar vertebra

A corpectomy of the first lumbar vertebra and combined corporadesis with MES and a Centaur lateral plate (Stryker) were performed. Along with the advantages, the main one of which is the relative cheapness of this implant, MES is also not an ideal design for anterior corporedesis and, in our opinion, has a number of disadvantages: 1. Most domestic MES do not have installation tools for cutting and modeling along the length, which requires special on the part of the surgeon, at great physical cost, using improvised unadapted instruments (various types of wire cutters and wire saws). 2. When implanted into its bed, the MESH can easily become deformed and bent (does not tolerate knocking with impactors). 3. MESs without end plates (most often domestic) have sharp edges, due to which it is possible to push through the end plates of the supporting vertebrae with a violation of stability in the operated segment. 4. Requires the use of additional clamps.

Various implants made of inorganic compounds - corundum ceramics, titanium nickelide, hydroxyapatites.

The advantages of these body replacement products are good biocompatibility with bone tissue and the ability for it to grow into an implant due to its high porosity, relative low cost, and ease of modeling the required shape and size. These implants are similar in their characteristics and properties to autologous bone, but do not have such a disadvantage as possible resorption, but unfortunately some implants of this type are quite fragile and can crumble and crack during implantation; in addition, as in the situation with autologous bone, they require the use of additional devices for fixation - plates, transpedicular fixators, etc.

Fundamental Stabilization Techniques

Currently, stabilization can be carried out using various open and percutaneous methods; below we will briefly introduce the most common of them.

Dynamic stabilization is a method of implanting dynamic implants, thanks to which the problematic region is stabilized to normal levels, while in general the biomechanics of the segment is preserved, but does not go beyond non-physiological amplitudes. The implant is primarily installed between the spinous processes of the problematic vertebral bodies in the lumbosacral part. The need often arises with radiculopathy, sequestered hernia, posterior displacement of the vertebrae, and foraminal stenosis.
Transpedicular fixation - this tactic involves installing a corrective metal structure, which is screws that are rigidly connected to each other with special rods, into the adjacent vertebral bodies through the pedicle (pedicles).
Similar manipulations are prescribed for fractures and displacements of the vertebrae, severe progressive scoliosis and spinal stenosis. Transpedicular fixation for scoliosis.
Transcutaneous stabilization is a technique for minimally invasive introduction of a stabilizing implant into the spine, which is implemented percutaneously (transcutaneously). To introduce the transcutaneous model of the fixator into the segment of interest, a small incision (up to 1.5 cm) is used. A surgical probe is inserted into it, through which, under image intensifier control, the implant is delivered to the problem area and the implanted system is securely fixed to the bone structures. Percutaneous surgery is characterized by minimal trauma, and therefore it is especially relevant for patients with poor health, cancer patients and the elderly.

Dynamic stabilization of the lumbar region.

Which technique for connecting the vertebrae will be the most rational in a particular case is chosen by the surgeon individually based on diagnostic data, anatomical features of the musculoskeletal system, health status, weight, age and other characteristics of the patient’s body.

Telescopic vertebral body prostheses

Traditionally, Western European and American manufacturers of telescopic vertebral body prostheses are leaders in the Russian market. These devices themselves have a huge number of advantages over their structural predecessors: 1. There are a large number of types and sizes of implants, and high-tech tools are included for high-quality installation. 2. Thanks to the end platforms with different kyphotic and lordotic angles, the natural curves of the spine are simulated. 3. Using a sliding telescopic device, they are tightly fixed in their bed. 4. If necessary, they can be easily dismantled. 5. They have the possibility of minimally invasive endoscopic installation (vertebral body prosthesis Obelisk, Ulrich, Germany in combination with the Golden Gate side plate), etc. But, unfortunately, the high cost often limits the use of these devices in Russian practical medicine. In addition, telescopic vertebral body prostheses also require additional fixation using plates or transpedicular devices to impart rotational stability.

Rehabilitation after surgery with metal structures

It is important to understand that the spinal system has undergone internal surgical intervention, and global changes have occurred in the anatomical structures in order to correct the distorted and destabilized segment. The operated part needs time to fully recover. In addition, the metal structure must take root well, and the patient must adapt to it. Therefore, be patient, the feeling of discomfort will pass, your musculoskeletal potential will normalize, and you will forget that you even have an artificial device in your spine.

But keep in mind that a successful outcome is only possible if postoperative recovery is carried out competently and with very high quality. Please note that in 80% of complications are a direct consequence of the patient underestimating the role of rehabilitation after such interventions , an inadequately organized treatment and rehabilitation program, or, even worse, its complete absence.

Only correct and impeccable compliance with all highly professional medical recommendations will allow you to return to a full life and avoid various types of consequences: deep infections, displacement of installed structures, muscle atrophy, degenerative lesions of nearby segments, relapse of instability, spinal stenosis, damage to the ligamentous apparatus, etc.

Clinical example

Fracture of the first lumbar vertebral body

Type of surgical wound. In place of the removed vertebral body, after decompression, a vertebral body prosthesis was installed Obelisk, Ulrich, Germany

The prosthesis is additionally fixed with a thoracolumbar plate.

X-ray control after surgery.

Exercise therapy after spinal surgery with metal structures

Life after spinal surgery associated with the implantation of a metal structure, as many characterize it, began to take on meaning compared to the preoperative state. With the ideal installation of a metal structure and the subsequent rehabilitation that is no less flawless in all aspects, the painful syndrome no longer bothers you, the range of motion increases noticeably, and it becomes possible to do household chores without difficulty and with pleasure, go to your favorite job, and even do simple activities. kinds of sports. Of course, not everything comes at once, as it is not difficult to figure out, people try their best to finally feel like a physically complete person and maintain the results achieved for life.

Procedures in water.

In addition to the fact that patients must keep themselves within certain lifelong restrictions (monitor their weight, do not overload the spine, do not carry heavy objects), it is extremely important for them to perform special exercises every day, even after completion of rehabilitation. Therapeutic exercises after recovery will help keep the muscles in normal tone. After all, it is the muscles that serve as the main support, regulator of the load and mobility of the spinal column, as well as any osteo-articular part of the musculoskeletal system. The weakness of muscle tissue causes metabolic and circulatory disorders and, as a consequence, the development and progression of degenerative phenomena in the vertebrae, cartilage, and intervertebral joints. Naturally, after undergoing an operation, no one wants to face a recurrence of the problem or the sudden appearance of a cascade of new difficulties.

Surgical sutures approximately 3 months after surgery.

The development of exercise therapy is carried out by a specialist who knows all the intricacies of the surgical process, the characteristics and dynamics of the patient’s functional state and other important characteristics. Therefore, we have no right to recommend you a complex of therapeutic exercises for any period. There is no universal gymnastics for everyone! For our part, we can only point out the importance of physical therapy, both in the early and late periods, and at long-term stages. Remember that in the delayed period it is the only and most effective means of resisting the development and progression of spinal diseases. Please also note the points below.

Appearance of the implant

The prosthesis is placed between the bodies of adjacent vertebrae.

Intraoperative X-ray control.

Thus, a promising direction in implantology of spine surgery is the creation of new, universal vertebral prostheses that allow quick, convenient, reliable and simultaneous performance of corporedesis.

Details of surgical treatment of scoliosis

Patients should be aware that there are significant risks associated with scoliosis surgery. In general, the process of spinal fusion is as follows:

Patients are given anesthesia for a surgery duration of 4 to 6 hours.
Various approaches can be used to access the spine. These may include a posterior, anterior or lateral approach. Sometimes a combined approach is used, and some use a thoracotomy to access the spine through the chest.
The spine is reconstructed using various metal instruments. Often the spinal joints are also removed and replaced with a bone graft. The patient may receive bone material from another part of the body - this is called an autograft, or donor material or synthetic material may be used. These external sources do not always take root, as the body can reject these materials.
Some patients with very large curves undergo multiple surgeries. In this case, the first stage is to release the spine in the area of curvature by cutting the muscles and ligaments, and the patient is in halo-femoral traction for several weeks. During this time, the spine may lengthen, and then the fusion is performed during the second stage.

Recovery and prognosis after surgical treatment of scoliosis

Such a complex operation requires a significant recovery period.

The time spent in the hospital postoperatively will vary, but most patients are on strict bed rest for 3-4 days.

During this time, various tubes may be used to drain excess fluid in the chest if a thoracotomy is being performed, and catheters and fluids help maintain normal functions of eating and removing waste products. Many patients experience pain after surgery and require epidural anesthesia, with subsequent transition to oral analgesics. Rarely, children may be prescribed rigid corsetry after surgery.

Patients do not realize that it takes time before they see tangible results from surgery. Although the spine may initially appear straighter, it takes at least three months before consolidation occurs and up to 2 years for complete fusion.

Conservative treatment of scoliosis, based on specific exercises, can produce significant results in as little as two weeks and does not involve pain or the risk of surgery. Therefore, surgical treatment of scoliosis is a necessary measure.