The percutaneous or key-hole technique is a very important part of our practice. While it is an invasive method, it is the most risk free. It was developed more than ten years ago and is increasingly becoming the method of choice since every branch of surgery strives to offer the most help with the least damage to its patients.
The percutaneous technique is excellent for diagnostics as well as therapy. By penetrating the body through an opening of just a few millimeters and manipulating the needle inside the body, we can gain invaluable information not possible with other non-invasive methods. It can help us determine the method of treatment or may even be the treatment itself.
Various diagnostic methods make it possible for us to gain valuable information regarding the body's condition and the status of an illness without in any way damaging or puncturing the body. These are, what we call, the non-invasive diagnostic methods and include the ultrasound (US), thermography, radioisotope, computer tomography (CT) and magnetic resonance imaging (MRI) techniques. The ultrasound is not useful in the diagnosis of spine disorders while, others, such as thermography are not yet medically accepted. The remainder are accepted methods of diagnosis that can be successfully used, however, the information to be gained is limited and in some cases, not enough. Another disadvantage is that the image is static and can only be taken with the patient in the prone position without any weight bearing down on the body. This makes finding the source of pain difficult even with a thorough physical examination, thus, minimally invasive diagnostic methods such as myelography and/or discography may have to be used.
An organic iodized contrast material is injected into the cerebrospinal liquid bounded to check for compressions or deformities on the dura sac which might negatively affect the nerves running through the dura sac and cause pain. Since similar information may be obtained with Ct and MRI scans, myelography has been pushed into the background recently, especially, due to the resting period of several hours required following the examination, possible severe headaches and, though seldom, allergic reactions.
There are some instances, however, where neither MRI nor CT examinations are possible. These are cases where the area to be examined contains previously surgically implanted metal: The magnetization of the metals precludes the use of the MRI and the disturbances affect the quality of a CT. Unfortunately, however, metal that cannot be magnetized also poses a problem since it can also affect the quality of the images and the more metal is present the more the quality is affected. In these cases, myelography can provide very significant information otherwise, perhaps, not attainable.
One of the most important components of the spine and playing a significant role in its three functions - support, motor function, protection - and also most prone to injury, is the intervertebral disc. In most cases, the source of a patient's pain can usually be found by careful history annotation, thorough physical examination and proper diagnostic imaging procedures. In cases, however, where more than one intervertebral disc is shown to be damaged, other supplementary information may be necessary, in which case, discography may help, on the one part, to locate the pain source and to determine the degree of degeneration, on the other. Contrast media containing iodine is injected into the intervertebral disc which then colors its nucleus. If this procedure does not cause the patient pain, independent of the patient's condition, no surgery of the intervertebral disc is necessary. If, however, the procedure does cause pain and conservative treatments have proven to be ineffective, surgery might be necessary with the type of surgical intervention decided according to the morphology of the disc. In advanced degeneration, that is serious injury to the intervertebral disc, open surgery might be indicated while, in cases of beginning degeneration, where the structure is relatively well maintained, percutaneous techniques might be the intervention of choice.
Therapy and Diagnostics in One
Over the past ten years, musculoskeletal surgery (orthopedics) has very effectively used locally administered anti-inflammatory injections in the treatment of joint, ligament and other inflammatory conditions. These injections are made up of two components: a local anesthetic and a steroid for decreasing the inflammation. If the former has an immediate short-term effect, its effectiveness is an indication of the proper placement of the medication, thus, aiding in the process of diagnosis. If the steroid component attains the expected pain relief in two to three days, this not only is therapeutic but also a further diagnostic aid. Several areas of the spine may be treated with these procedures, even if only temporarily.
- The nerve root block is an injection into the sheath surrounding a nerve root in the spine to decrease pain temporarily and to define it more precisely. The patient is usually able to go home immediately afterwards.
- Facet joint block is an injection given into the sinovial joint or joints. The patient is usually able to go home immediately afterwards.
- Epidural block or sacral epidural adhesioliysis (SEA): is an injection given into the spinal canal that might be effective in cases of irradiating lumbar pain. The patient is usually able to return home following a 1-2 hour rest period.
Percutaneous Surgical Methods
The advantage of this type of surgery is that it is performed through tiny incisions, allowing the surgeon to work in a “closed" environment to reach and treat the affected area. The surgeon is guided by an x-ray monitor, an endoscope or surgical navigation system or both. The small incision causes little damage to tissues during penetration, no general anesthesia is required, is usually done under a local anesthetic, or at most, under intravenous narcotics. Another tremendous advantage is the short hospital stay, short rehabilitation period and quick return to normal daily activities. Because of the relatively small space available to the surgeon for navigating inside the body, the cases to be treated with this method need to be selected very carefully.
Percutaneous Intervertebral Disc Decompression
Intervertebral disc decompression, or the diminishing of pressure, is one of the oldest known surgical procedures. The intervertebral disc is considered a closed hydraulic area. Partly due to trauma and partly due to genetic predetermination, the wall of the intervertebral disc may weaken, become thinner and, eventually, because of the internal pressure, herniated. The resulting protrusion causes space deficit, limiting the area available for the nerves thus resulting in pressure on the nerves which, in turn, causes numbness, pain, muscle strength deficit and restricted range of motion. If, during the examination process, we find that diminished pressure within the intervertebral disc and the elasticity of the posterior wall would cause the protrusion to withdraw, then one of the decompression procedures would be indicated. Manual instruments, automatic cutting and aspirating tools or laser may be used through the tiny incision. Conservative treatment must be tried before any surgery is attempted.
Percutaneous Intervertebral Laser Disc Decompression
Just as in all other treatment procedures, in order for it to be a success, the patient must be chosen carefully. We only perform this procedure when conservative treatment failed. In these cases, the lumbar MRI shows a dehydrated intervertebral disc with its height almost maintained and which physical examination shows to be the source of the complaints. We next perform a discography to confirm the source of pain, to ensure that the wall of the intervertebral disc is not damaged, is thick enough and that its elasticity will allow it to withdraw when the pressure is diminished. It should also be noted that the nucleus of the intervertebral disc must be completely enclosed and its capacity for absorbing contrast media should not under any circumstances exceed more than twice the considered normal maximum of 2 milliliters.
The procedure has been in use since 1987 with numerous medical reports attesting to its effectiveness but, it is important, however, to have the proper laser equipment with the proper settings. For these surgeries, the following three frequencies are used today: Holmium (2100nm), NdYAG (1064nm) and bisected YAG or ITP (532nm). Considering the tissue absorption curve, the Holmium frequency seems to be the most appropriate because, due to its maximal absorbency in water, its effect within the intervertebral disc can be maximal and, at the same, the danger of the beam passing through the tissue and reaching another area not intended, minimal. The laser beam has to be formed and the equipment set in such a way that all the energy is absorbed within 0.5 centimeters, causing all the tissue in its way to evaporate and leading to the desired decompression. At the end of the procedure, depo steroid is injected into the intervertebral disc to avoid the pain caused by the inflammatory reaction.
The spine must be treated with care for one week following the surgical procedure with only regular mild exercising. This is to be followed by two transitional weeks, following which complete weight bearing may be resumed together with the regular work activities.
Should the procedure not be successful (current medical literature, as well as our own experience, shows the success rate at 70%), the non-surgical treatment may be continued or open surgery may be chosen.
IDET (Intradiscal Electrothermal Annuloplasty)
We first started using the IDET, the newest percutaneous procedure, in 2006.
It is a fairly new procedure used mainly in cases where sensitive proprioceptors and pressure sensors of the intervertebral disc needlessly send signals and, thereby, causing pain. It is not used when protrusion occurs on the disc wall or when a disc wall is damaged. This is checked before the surgery with a discography or a distention test.
The intervertebral disc is first punctured with a hollow 1.2 mm diameter needle from a poster lateral direction. Guided by x-ray imaging, a catheter is then passed through the needle to the intervertebral disc where the flexible catheter will be positioned to the back inner wall.
Using a preset program, the catheter tip is then slowly heated up (usually to 90 degrees Celsius). The program routinely runs for 16 1/2 minutes. As the disc gradually heats up, the patient will experience pressure that might be somewhat uncomfortable, tension in the lumbar area and, perhaps, warmth in the lower extremities. The procedure is performed with a local anesthetic with the patient awake. Following the procedure, the same instructions apply as for the percutaneous laser decompression above.
Percutaneous strengthening of fractured vertebrae (Percutaneous Vertebral Augmentation)
Patients with osteoporosis are prone to bone fractures. The most common among these is compression, or the collapse of a vertebra. Although the spine remains stable and does usually not require surgical intervention, it is nevertheless very painful, limiting or even impeding mobility with the symptoms lasting three to four months. In addition, the compression causes the kyphotic (humpback) curvature of the spine to increase forcing the body to bend forward and adding to the risk of fracture which further threatens those suffering from age-related diminished bone density. When the height of the collapsed vertebra is restored, however, the kyphosis decreases, the danger of a new fracture decreases and the pain is also relieved. Deciding, however, as to which of the previously collapsed and then healed vertebra is the one freshly fractured and suitable for this intervention is not always simple. The CT scan, MRI and isotope examinations are prevailed upon here.
This method was first used in 1984 in the case of a vertebral haemangioma (benign tumor of the blood cells) and spread slowly, gradually. It is mostly used, nowadays, in cases of painful vertebra compression due to osteoporosis not responsive to conservative treatment or when the vertebra lost excessive height. During the procedure, a 4 mmą canula is led, under x-ray based navigation, from one or two sides into the compressed vertebra. Through this canula, liquid cement, that is almost set, is injected into the center of the vertebra. This, then, holds the broken pieces together and, the pain that had been caused by the instability, is immediately and drastically reduced. This procedure is seldom used for reestablishing a vertebra's original height or for raising it since, if not used properly, the cement may spill out of the vertebra. This type of clinically significant complication only occurs in less than one percent of cases. In order to avoid these cases, we very thoroughly examine our Patients before surgery and tightly monitor them during and after surgery. The need to reestablish a vertebra's original height and decrease the number of complications resulting from cement spillage, has led to the development of balloon kyphoplasty.
In balloon kyphoplasty, developed in 1997, two balloons are placed into the fractured vertebra percutaneously through tiny 1 cm openings (two per vertebra). The balloons are then blown up restoring the collapsed vertebra to its original height. The balloons are then deflated and the cavity thus created is half filled with liquid cement. Following this, the patient will be able to get out of bed the following day, the spine weight bearing and mobilization continued with no further aids and the need of minimal pain relief. The technique may be applied from the fifth dorsal to the last lumbar vertebra. Since its introduction, the number of cement spillage cases has decreased significantly. The high cost of the procedure, however, compared to vertebroplasty, restricts its use. Current studies aim to define the cases that absolutely require the more costly procedure and to reduce the cost through new developments.
Such an innovation is the hydraulic press for introducing solid bone cement or a Hungarian invention that by electrothermally treating bone cement, increases its viscosity. Another new development is stenting wherein balloon catheters are introduced armed with stents and a technique, not available in Hungary, wherein thin discs are shot into the compressed vertebra, thereby augmenting the endplate.
Special surgical aids
- The Microscope: a magnifying tool used in conventional surgical techniques. Helps increase the surgeon's effectiveness through better illumination and definition and, oftentimes, makes smaller incisions possible.
- The Endoscope and the Digital Camera: these are important aids in minimal invasive surgical procedures, magnifying, illuminating and allowing internal manipulation without having to resort to open surgery. It also makes lavage (flushing out with water) possible.
- Surgical Lasers: our lasers are of three varying frequencies (in two units) and applied in various situations
- The invisible Holmium laser with a frequency of 2100 nm, is absorbed well in water, is useful in cases involving transparent tissue and for cutting. The Impulse laser has a capacity of 40 Watts, is ideal for working within the intervertebral disc, the epidural area and the lumbar spine foramen with or without endoscope assistance.
- The Nd-YAG or Neodynium laser with a frequency of 1064 nm is not as easily absorbed in water and allowing it to dangerously penetrate transparent tissues. We use its half strength the KTP 532 nm frequency green beam. With its 40 Watt capacity and good absorption in red tissues (i.e., hemoglobin, blood) it is useful in tumor surgery and in the resection of intervertebral tissue previously injected with contrast media.
Surgical Navigation or Computer Assisted Surgery (CAS)
Of all the surgical navigation systems, the Computer Assisted Surgery or CAS is the newest. This system allows the surgeon to follow the progress of an ongoing surgery on a previously taken X-ray, CT or MRI and precisely locate and follow the path of a surgical instrument within the patient's anatomy. This method also makes more accurate surgical procedures such as tumor removal possible and saves a patient from further x-ray exposure during surgery. Fortunately, our department has one of these most modern equipments which we routinely use daily for internal fixations with metal implants or for other interventions requiring a high level of accuracy.