1st Edition, February 2008
Birkenmaier, J. Chiu, A. Fontanella & H. Leu
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With endoscopic back surgery, it is aimed to reduce tissue trauma, prevent iatrogenic problems, and preserve spinal segmental motion and stability.
The most interesting advantages of endoscopic procedures compared to open surgery are;
Smaller incision and less tissue trauma,
Minimal blood loss
Early return to daily activities and work
Easier surgical approach in obese patients
Conscious sedation and local and regional anesthesia can be used together
Less need for post-operative pain management in many cases
As a result, they are procedures in which outpatient treatment is possible.
Summary
The International Society for Minimal Intervention in Spine Surgery (ISMISS) is an association of professionals dealing with back surgery from all continents, with the general aim of reducing interventional trauma and iatrogenic problems in spinal interventions.
Members of the ISMISS founding members are pioneers of endoscopic spinal surgery, while members include experts from all areas of spinal treatments, from minimally invasive pain interventions to disc arthroplasty and fusion surgery.
Since its inception in 1989, ISMISS has worked to improve the understanding of the underlying pathology as well as the development of tools and techniques for endoscopic spinal surgery.
ISMISS is affiliated with SICOT (International Society of Orthopedic Surgery and Traumatology) and supports SICOT, which aims at clinical skills, training and scientific advancement in the field of spinal procedures.
As new procedures, instruments and techniques are discovered, published and marketed faster than ever, ISMISS recognizes that adequate evaluation of treatments in this area is becoming increasingly difficult.
ISMISS has begun to prepare independent and diverse guidelines on minimally invasive procedures in order to gain some habits to waist health professionals who want to improve their clinical practice with the latest and best information.
These guidelines have been prepared on the basis of a thorough and detailed evaluation of the existing literature and the experiences of experts selected from ISMISS members all over the world and accepted as experts in their fields.
The primary focus of the ISMISS guidelines is endoscopic spinal surgery.
Correction
The field of endoscopic spinal surgery is still very new and developing rapidly.
As a result, experiences and observations may differ markedly across cultures, beliefs, and surgical practices.
Therefore, we do not claim that these guidelines are whole or specific to any particular case.
This work is still evolving and will continue to be updated regularly as new techniques and technologies are introduced, studied and improved.
Although updates are planned twice a year, new updates will be made at shorter intervals when necessary.
We invite you to participate in this study and share your clinical experiences or research with us.
Gold Standards
The majority of endoscopic spinal procedures relate to the surgical treatment of lumbar and spinal disc herniations, where microsurgery using the operating microscope is the gold standard when conservative treatments have failed or are not indicated.
Microscopic disc surgery with microsurgery, also called microdiscectomy, should be taken as a reference in comparison with endoscopic disc surgery.
For many other conditions, such as spinal canal stenosis or painful degenerative disc disease, an undisputed gold standard treatment has yet to be defined.
In any case, the main concern of the technical advantages of endoscopic spinal surgery should be patient safety.
As a result, all endoscopic spinal procedures aim to increase patient comfort, decrease invasiveness and not increase the complication rate and risk profile when compared with traditional procedures applied for the same indications.
Indications
Endoscopic strategies have been and are predominantly used in the treatment of the following conditions:
Lumbar, thoracic and cervical disc herniations with radicular symptoms
Lateral spinal canal (recess) and foraminal stenoses with radicular symptoms
Degenerative facet joint cysts with radicular symptoms
Contraindications
Clinically consistent instabilities
central spinal canal stenosis
Relative contraindication: Large disc herniations and concomitant cauda equina syndrome or new motor deficit. In these cases, adequate decompression may not be achieved except for those with large interlaminar space and good interlaminar endoscopic access.
Diagnostic Standards for Determining Indication
In each of the above-mentioned cases, a clear clinical profile completed using patient history and physical and neurological examination is the minimum standard.
While degenerative changes seen in radiography and magnetic resonance imaging (MRI) determine the prevalence in asymptomatic cases, evaluation with imaging methods alone can be extremely misleading in such cases when pathological findings do not clearly match with specific clinical symptoms.
Physical examination of cervical and lumbar spinal pain syndromes should include the shoulder region, upper extremity, pelvis, sacroiliac joint, and hip joints, respectively.
It is not uncommon for painful conditions in these adjacent areas to mimic symptoms resulting from spinal events.
In doubtful cases, we recommend contrast assisted diagnostic injections under fluoroscopy guidance to detect the condition that can be treated with endoscopic spinal surgery.
A current MRI with adequate and new imaging studies, or computed tomography (CT) is required for surgical procedures in patients with a history of less than 3 months and in whom MRI would not be preferred for imaging.
In cases with a change in symptoms, a repeated imaging study is recommended before surgery.
If the diagnosis of the monoradicular lesion is doubtful despite the history, physical examination, and imaging studies, additional neurophysiological studies (electromyography, neurography, etc.) may be helpful.
Evaluation of Imaging Studies
Plain Radiographs
Plain radiographs taken in bidirectional and upright position are still considered standard examination for 2 reasons:
On the one hand, plain radiographs allow rapid assessment of spinal structure, bone integrity, and potential instability.
On the other hand, it allows the evaluation of vertebrae when radicular symptoms do not match the level of the affected disc observed on MRI or CT.
Functional radiographs may also be necessary in cases of suspected or identified instability.
In selected cases, functional myelography can be a highly valuable test even today (see below).
Computed Tomography (CT)
Although MRI has replaced CT in evaluating soft tissues, edema, infection, cysts, and other fluid-induced tissue changes, CT still has significance in some diagnostic situations.
Apart from MRI, CT can also create images in alternative and also non-standard planes using the original data, thus helping to evaluate foraminal events.
Many foraminal problems arise from bony structures, and these bony structures often cannot be adequately evaluated with available MRI resolution and images.
This is especially observed in the cervical spine.
In cases where MRI cannot be applied, post-myelography CT is a valuable imaging method superior to MRI.
Hyperbaric contrast agent application, which is entered from the lumbar level in cervical problems, is an alternative option to the suboccipital technique.
Magnetic Resonance (MRI)
Many modern magnets (!) Get very good and detailed images when it comes to disc space, ligaments, fluid compartments, neural structures and adipose tissue.
On the other hand, sagittal sections often fail to show the posterior foramen enough to assess extraforaminal disc sequestration.
When combined with axial slices not parallel to the level of the affected disc, this may miss extraforaminal sequestrations.
With the exception of some exceptional centers where functional MRI is used, CT and MRI imaging are usually performed in the supine and sometimes prone position, without axial loads and positional effects on the spine.
In some cases, as an effect of body weight, instability, and posture, standing images may appear quite different on CT or MRI than images taken in the supine position.
When this condition is suspected, a functional myelogram followed by post-myelography CT is a good option.
The fact that functional MRI is an alternative imaging method seems promising for the future. Due to the limited position tolerance in patients suffering from pain today, image noise may occur and therefore the image quality may be adversely affected.
Anesthesia
Although general anesthesia is preferred by many surgeons for traditional techniques, local anesthesia with or without sedation is an important option for most endoscopic approaches.
However, one of the issues that should be emphasized is that a patient lying prone and undergoing local anesthesia may need to completely abandon the technique used and switch to general anesthesia, as well as the need for endotracheal intubation, repositioning the patient and re-preparation of the operation field.
Especially in cervical applications, unconscious head and neck movements are very difficult to control and may cause additional risks.
Endoscopic Approaches to the Lumbar Spine
Anatomical and Technical Evaluation
Endoscopic spinal surgery uses dilatation technology instead of making a skin incision in order to minimize tissue trauma in providing the transition from soft tissues (eg skin, subcutaneous adipose tissue and muscle/fascia tissue).
Beyond the entry trauma to the tissue, the main difference between endoscopic and microscopic microsurgery is; It provides a 2D view versus a 3D view, and a near view angle versus a far view angle, even though it’s flat.
Many instrument sets for endoscopic back surgery are available on the market, and they come in a wide variety according to their technical features and indications for use.
Each surgeon is responsible for using the most appropriate surgical set for his/her own surgical technique.
While the endoscopic surgical approach to the spine reduces visible surgical trauma, this minimally invasive procedure comes at a cost; a reduced and 2-dimensional field of view and a limited field of view in the surgical field.
The surgical approach and access route are chosen largely depending on the regional anatomy for entry into the foramen or spinal canal.
These anatomical restrictions are usually caused by bone structures such as facet joints, pedicles and laminae, however, branches originating from nerve roots in foraminal approaches and vertebral arteries in cervical approaches are also important structures that cause restrictions.
The properties of the optical system (viewing angle, magnification, etc.), together with the size of the treated canal and the instruments used, determine the precise limits such as which areas can be seen and which lesions can be treated safely.
Burr, promotion, etc., which allow endoscopic bone resection from the operation area and enable a larger view by enlarging the operation area. surgical instruments such as.
On the other hand, when it is necessary to change the location of the instruments used from the additional access cannulas, blinding augmentation and a large amount of bone resection are required with the terfin.
For these reasons, a clear surgical strategy and precise targeting are very important.
Double-arm fluoroscopy is a prerequisite for the approach used to be directed to the right place, intraoperative control and recording of the technique used.
If the techniques that cause tissue change such as laser or bipolar radiofrequency devices are to be used in endoscopic spinal surgery, the instruments considered to be used and their complications should be fully known.
Interlaminar Approach
This approach is very similar to the traditional microsurgical approach.
The spinal canal is entered through a limited flavotomy and the risk of damage to the dura or neural structures is similar to the microsurgical approach.
Depending on the angle of entry into the interlaminar space in the sagittal axis and the level of treatment, reaching the posterior part of the disc may be easy or difficult.
Since the interpedicular area is on the opposite side of the ventral epidural area, it is very difficult to reach.
When the interlaminar window is too small, this approach cannot be applied without resecting the laminar edge and / or the medial part of the facet joint. This is particularly important for newer and more modern endoscopes with a wider working channel as well as a larger outer diameter.
An important advantage of this approach is that it can easily be converted to the open approach.
Posterolateral Approach
The posterolateral approach is the best known approach for interventions on the lumbar spine and can be used in foraminal and extraforaminal disc herniations as well as intradiscal procedures.
In this approach, an angle of approximately 60 degrees is made to the sagittal plane and the foramen is entered from the disc level.
It can be applied when the patient is in a prone or lateral decubitus position.
In this approach, the main intraoperative risks are damage to the root originating nerve (especially in the presence of severe disc height loss) and damage to the blood vessels.
In patients with short pedicle structures and osteophytes in the facet joints, the lateral edge of the superior articular process may need to be shaved to provide sufficient transition clearance. The ventral epidural space can only be reached from this side.
Far or Extreme Approach
This approach is one of the most recently developed approaches, and it was developed especially under the leadership of Ruetten.
Using this approach, in addition to the foraminal and extraforaminal areas, the ventral epidural space other than the interpupicular area can be accessed.
This approach provides access to the foramen by making an angle of less than 90 degrees to the sagittal plane, at the level of the facet joints in the coronal plane and through the skin in the prone position.
Therefore, it is less likely to encounter facet joints than the posterolateral approach, but in this approach, short pedicle structures and large herniated discs may make it difficult to pass to the ventral epidural area.
The risks of surgical intervention are generally the same as for the posterolateral approach, but there is an increased risk of dural injury and an additional risk of injury to the retroperitoneal organs at the upper lumbar levels.
Therefore, the retroperitoneal anatomy of the CT or MRI related level should be examined before applying this approach to the upper lumbar levels.
Endoscopic Approaches to the Cervical Spine
Anterior Approach
The anterior approach is very similar to the traditional microsurgical method in which the neurovascular sheath is taken to the outer part of the working canal and the visceral structures to the inner part of the studied canal.
The tip of the working arm is placed opposite the end of the anterior longitudinal ligament and the anterior part of the adjacent vertebral body.
Unlike traditional microsurgery, disc space can be passed without any discectomy.
Cleaning of the herniated disc and osteophytes, if necessary, is accomplished by using a wide variety of special tools, including chisels, pitchers, microresectors, various forceps, drills, hooks and bipolar microelectrodes.
Using this approach, the foraminal areas and spinal canal can be reached with perfect control of the operation area, while the same accessibility is not valid for the interpupicular space.
The anterior endoscopic approach in the cervical spine relative to other parts of the spine facilitates effective decompression of the spinal canal and / or nerve roots (in addition to the vertebral arteries in selected cases) without the need for disc removal using fusion or arthroplasty.
In general, there is no need for drains or immobilization for the wound in the postoperative period.
Posterior Approach
The posterior approach is advantageous in central spinal canal stenoses caused primarily by posterior structures (primarily by the ligamentum flavum or a collapsed laminar edge) or distant lateral disc herniations.
The approach and surgical technique are quite similar to the traditional surgical technique, but in practice, tubes of various diameters and typical endoscopic instruments that pass through them and mentioned in the anterior approach are used.
Complications
Minimally invasive surgery does not have to bring minimal complications, the learning curve of endoscopic low back surgery tends to be flat and longer than traditional approaches.
Dural tears, nerve root damage, bleeding and infection, applications to the wrong level or the wrong side of the hernia can be seen in endoscopic techniques as well as in open techniques.
There is also a risk of pneumothorax in thoracic approaches.
In addition, some injuries such as dural tears may not be taken seriously or even noticed due to the low pressure washing system of the endoscopic system.
When a surgeon begins to perform endoscopic spinal surgery, careful selection of appropriate cases, careful surgical technique, administration of a single perioperative antibiotic (1), and careful postoperative follow-up are highly recommended.
When complications occur, it is necessary to evaluate the cases with the same technique as it is applied in open techniques and, if necessary, to switch to open technique.
Surgeon’s Qualifications
Only surgeons who have sufficient experience in their traditional techniques should apply endoscopic techniques.
On the one hand, sufficient experience is required to properly manage potential complications, on the other hand, surgeons with sufficient experience in both techniques can decide whether the open technique or the closed endoscopic approach is better in each case.
Adequate training in endoscopic techniques, technical resourcefulness with the instruments used are a priority for the procedures to be applied in clinical situations.
Evidence
A recent update on the systematic review of the Cochrane study on lumbar disc prolapse found that surgical discectomy (open and microsurgical) applied to carefully selected patients provided faster regression in sciatica pain than conservative treatment (2).
It was also mentioned in the same review that there is insufficient evidence to draw correct conclusions on all types of percutaneous discectomy (there is sufficient evidence for chemonucleolysis only).
In a systematic review by Maroon, it was reported that none of the minimally invasive techniques developed to be used in the treatment of symptomatic lumbar disc disease had a significant superiority over microdiscectomy (3).
It is understood from this that well-designed random studies are needed to compare endoscopic techniques with microsurgical microscopic disc surgery.
Most of the publications on endoscopic spinal procedures include the results of case series (usually retrospective), technical developments or personal experiences.
However, there are few controlled and randomized controlled studies that can provide evidence about the potential benefits of endoscopic disc surgery.
In a randomized controlled study performed in a selected patient group (cases with a single level herniation not exceeding ın of the spinal canal in the sagittal plane, cases without spinal canal stenosis) similar clinical results were obtained in terms of performing endoscopic and open discectomy, however, patients who underwent endoscopic surgery had less postoperative pain and It has been found to have a shorter rehabilitation period (4).
In another controlled study, endoscopic disc surgery was found to be superior to microsurgery technique in terms of sciatica pain, low back pain and return to work (5).
It has been proven that endoscopic lumbar surgery not only causes smaller incisions, but also causes less tissue damage and a lower systemic inflammatory response (6).
In a controlled study in which intraoperative electromyographic monitoring was used and endoscopic and open techniques were compared, it was found that significantly less intraoperative nerve root irritation occurred in patients who underwent endoscopic technique (7).
Resources
Dimick JB, Lipsett PA, Kostuik JP. Spine update: antimicrobial prophylaxis in spine surgery: basic principles and recent advances. Spine. 2000 Oct 1;25(19):2544-8.
Gibson JN, Waddell G. Surgical interventions for lumbar disc prolapse. Cochrane Database Syst Rev. 2007(1):CD001350.
Maroon JC. Current concepts in minimally invasive discectomy. Neurosurgery. 2002 Nov;51(5 Suppl):S137-45.
Hermantin FU, Peters T, Quartararo L, Kambin P. A prospective, randomized study comparing the results of open discectomy with those of video-assisted arthroscopic microdiscectomy. J Bone Joint Surg Am. 1999 Jul;81(7):958-65.
Mayer HM, Brock M. Percutaneous endoscopic discectomy: surgical technique and preliminary results compared to microsurgical discectomy. J Neurosurg. 1993 Feb;78(2):216-25.
Huang TJ, Hsu RW, Li YY, Cheng CC. Less systemic cytokine response in patients following microendoscopic versus open lumbar discectomy. J Orthop Res. 2005 Mar;23(2):406-11.
Schick U, Dohnert J, Richter A, Konig A, Vitzthum HE. Microendoscopic lumbar discectomy versus open surgery: an intraoperative EMG study. Eur Spine J. 2002 Feb;11(1):20-6.
Additional Resource
Chiu JC, Hansraj KK, Akiyama C, Greenspan M. Percutaneous (endoscopic) decompression discectomy for non-extruded cervical herniated nucleus pulposus. Surg Technol Int. 1997;6:405-11.
Chiu JC, Clifford TJ, Greenspan M, Richley RC, Lohman G, Sison RB. Percutaneous microdecompressive endoscopic cervical discectomy with laser thermodiskoplasty. The Mount Sinai journal of medicine, New York. 2000 Sep;67(4):278-82.
Chiu JC. Anterior Endoscopic Cervical Microdiscectomy. In: Kim D, Fessler R, Regan J, editors. Endoscopic Spine Surgery and Instrumentation. New York: Thieme Medical Publisher; 2004. p. 48-55.
Fontanella A. Endoscopic microsurgery in herniated cervical discs. Neurol Res. 1999 Jan;21(1):31-8.
Kambin P. Arthroscopic microdiskectomy. The Mount Sinai journal of medicine, New York. 1991 Mar;58(2):159-64.
Kambin P. Arthroscopic microdiscectomy. Arthroscopy. 1992;8(3):287-95.
Kambin P. (Editor) Arthroscopic and Endoscopic Spinal Surgery Text and Atlas, Second Edition, Humana Press, Totowa, NJ
Leu H, Schreiber A. [Percutaneous nucleotomy with discoscopy: experiences since 1979 and current possibilities]. Revue medicale de la Suisse romande. 1989 Jun;109(6):477-82.
Ruetten S, Meyer O, Godolias G. Endoscopic surgery of the lumbar epidural space (epiduroscopy): results of therapeutic intervention in 93 patients. Minim Invasive Neurosurg. 2003 Feb;46(1):1-4.
Ruetten S, Komp M, Godolias G. An extreme lateral access for the surgery of lumbar disc herniations inside the spinal canal using the full-endoscopic uniportal transforaminal approach-technique and prospective results of 463 patients. Spine. 2005 Nov 15;30(22):2570-8.
Schreiber A, Suezawa Y, Leu H. Does percutaneous nucleotomy with discoscopy replace conventional discectomy? Eight years of experience and results in treatment of herniated lumbar disc. Clinical orthopaedics and related research. 1989 Jan(238):35-42.