Spinal surgery has traditionally been an important subfield of neurosurgery. The diseases it studies and treats are also a group of common central nervous system diseases that seriously endanger people’s health, mainly including intravertebral tumors, spinal cord spinal vascular malformations, spinal cord spinal congenital diseases, spinal cord injuries, herniated discs and other partial spinal diseases, as well as intravertebral infectious diseases and spinal nerve diseases.
In recent years, unprecedented advances in spine surgery have been made, with the development of minimally invasive spine techniques being particularly noteworthy. Typically, minimally invasive spine surgery connotes minimally invasive techniques that apply multiple approaches to spine surgery, including small access, microinvasive and endoscopically assisted, channel expansion and imaging navigation.
With the rapid development of surgical instrumentation and computer imaging technology, minimally invasive surgical techniques have evolved from early percutaneous puncture nucleus pulposus chemical lysis, percutaneous puncture nucleus pulposus vaporization and microscopic lumbar discectomy to spinal decompression, fusion and internal fixation, and the international neurosurgical community has greatly improved the understanding and treatment of various spinal and spinal diseases.
First, the definition of minimally invasive spine surgery
At present, there is no consistent definition of minimally invasive spine surgery. We will define minimally invasive spine surgery as any spinal surgical procedure dedicated to reducing tissue damage.
According to the different therapeutic roles, minimally invasive spine surgery can be divided into the following categories.
1. injection techniques.
2. decompression techniques.
3. internal fixation and fusion techniques.
4, vertebroplasty and non-fusion techniques.
Minimally invasive spine surgery can also be divided into the following categories based on technique or surgical access.
1, percutaneous techniques: percutaneous puncture or microincision, using special instruments and devices to perform minimally invasive spine surgery.
2. thoracoscopic or laparoscopic (endoscopic) techniques: the spine is reached through several skin passages or tiny incisions, and surgical operations are performed under direct vision using optical fiber imaging technology. Endoscopic-assisted spine surgery techniques can be divided into thoracic and laparoscopic-assisted and microendoscopic-assisted spine surgery.
3. tubing techniques.
4, small incision techniques: the use of the operating microscope or high magnification, magnification of the surgical field of view for surgical operations, through the smallest possible skin incision to perform “keyhole surgery”, so that spine surgery with minimal medical source of injury to implement the most effective treatment. This includes anterior cervical surgical microscopic disc removal, posterior lumbar microsurgical disc removal (medial approach, lateral approach, extraforaminal approach), etc.
5, navigation system-assisted spine surgery techniques: is a new technology developed in the late 1990s, with the assistance of navigation systems, significantly improving the accuracy and safety of surgery and reducing complications. The advantage of minimally invasive spine surgery is that it can reduce patient complications and shorten recovery time, but minimally invasive spine surgery requires higher surgical skills and reliance on special surgical instruments, and the operating time is longer.
II. Minimally invasive percutaneous spine surgery techniques
Percutaneous intervertebral and epidural injection techniques have been widely used in the diagnosis and treatment of spinal disorders. The key point of the percutaneous technique is fluoroscopically guided, anesthesia followed by puncture at an appropriate location and injection of drugs with or without corticosteroids. Knowledge of the principles of this technique and the associated anatomy is fundamental to the performance of minimally invasive spine surgery.
Percutaneous disc techniques, such as chemical fusion of the disc, were once popular. Although these techniques are no longer prevalent, other techniques, such as discography, percutaneous myeloplasty, and intradiscal electrothermal therapy, all use similar surgical approaches. Percutaneous vertebroplasty is another minimally invasive percutaneous technique for the treatment of vertebral compression fractures.
It is performed by puncturing one or several guide pins through the pedicle or an extra-ventricular route and then injecting polymethylmethacrylate (PMMA) or a similar bone cement component into the vertebral body. The more recently developed percutaneous pedicle screw technique involves percutaneous placement of pedicle screws into the pedicle by fluoroscopic positioning or computer guidance. The greatest technical difficulty with the percutaneous pedicle screw technique is how to avoid excessive soft tissue stripping during placement of the fixation bar.
In addition, because there is no direct exposure of the posterior anatomy, bone graft blocks cannot be placed. Currently this technique is mainly used for posterior supplemental fixation after anterior fusion. However, the small incision technique can reveal and decorticate the posterior bony structures, thus creating the conditions for bone graft fusion.
The features of the percutaneous technique are introduced with percutaneous vertebroplasty and retrobulbar kyphoplasty and percutaneous radiofrequency ablation myeloplasty as representatives.
1.Percutaneous vertebroplasty and kyphoplasty
(1) Percutaneous vertebroplasty (PVP): It is a minimally invasive interventional therapy with percutaneous injection of bone cement. Since Galibert et al. first applied percutaneous intravertebral cement injection in 1984 to successfully treat a case of C2 vertebral hemangioma, this technique has been widely used for vertebral compression fractures and vertebral metastases.
Indications.
① vertebral compression fractures caused by osteoporosis.
(ii) vertebral body hemangioma.
③vertebral body metastases.
④ vertebral body eosinophilic granuloma and myeloma, etc.
Operated under C-arm X-ray machine fluoroscopy or CT positioning, the ideal location of the puncture trocar needle is in the anterior 1/3 of the vertebral body, and the amount of bone cement injection is usually 2-9 mL. the average 2.5 mL in the cervical spine, 5.5 mL in the thoracic spine, and 7 mL in the lumbar spine.
(2) Percutaneous vertebral kyphoplasty (PKP): The operation is to insert an expandable balloon through the pedicle approach, so that the damaged or fracture-compressed osteophytes are extruded in all directions and the diseased vertebral body is swollen and the original height of the vertebral body is restored, and then the bone cement is injected to harden the vertebral body.
PVP and PKP have similar indications and both have the effect of restoring the strength and stiffness of the vertebral body, but PKP can also be propped up to restore the height of the vertebral body, thus correcting the kyphosis deformity.
2.Percutaneous radiofrequency ablation myeloplasty
Percutaneous radiofrequency ablation myeloplasty is a minimally invasive cervical and lumbar spine surgery carried out in recent years. Its mechanism is to use the radiofrequency energy of plasma cold ablation technology to form a plasma field in the local tissue around the electrode and produce a large number of energy-carrying ionized particles, which cut off the tissue molecular connection and form a pore, and the thermal coagulation when withdrawing the working rod causes the collagen fibers around the pore to contract and degenerate and polymerize and solidify, thus reducing the intervertebral disc This reduces the irritation of the nerve roots by the soft tissue and relieves the pain.
The controlled and low-energy nature of cold ablation technology ensures its safety, while the low-energy nature determines the limitation of its decompression range, with less than 10% reduction of intra-disc volume by ablation.