Development of Full-Endoscopic Lumbar Spine Surgery

The goal of utilizing endoscopic techniques in spinal surgery is to access the affected area with precision, minimal harm to surrounding soft tissues, and with the intention of decompressing or fusing the area in question. To attain this goal, three primary elements are crucial:

• Endoscope that provides a magnified and unobstructed view of the area near the affected site
• A functional channel for the endoscope, accompanied by specially designed instruments for delivering energy to coagulate, a laser for dissecting soft tissue, and tools for resecting and extracting any loose fragments present in the surgical field.
• An irrigation system that provides a constant inflow and outflow, which aids in clearing away debris and maintaining a clear view during visualization.

Endoscopic spine surgery utilizes predetermined anatomical pathways for secure equipment passage during precise decompression and/or fusion procedures.

Kambin’s triangle is a specific target working zone that has been successfully decompressed using the transforaminal endoscopic lumbar discectomy (TELD) technique. Endoscopic equipment improvements, such as customized forceps and drills, have expanded the range of medical conditions that can be addressed through endoscopic spine surgery.

Transforaminal Endoscopic Lumbar Discectomy

Endoscopic spine surgery primarily involves TELD, but other techniques have been developed for accessing the secure working area, including inside-out, outside-in with foraminoplasty, and mobile outside-in techniques.

More extensive exploration of the spinal canal can be achieved through techniques such as partial removal of the pedicle and facet complex or resection through the pedicle, particularly in cases of migrated herniated discs.

TELD is an effective treatment for contained or low-level migration of herniated discs in the L1-5 region. It is applicable for disc herniation in central, paracentral, and foraminal regions.

Patients with radicular pain and MRI findings that do not respond to conservative treatment are typically the ones who would benefit from this surgery. The objective of the surgery has evolved over the years from central nucleotomy to discectomy and selective fragmentectomy.

The inside-out method is effective for treating patients with intracanal discs, while foraminoplasty has been developed to improve outcomes for patients with non-contained discs. Foraminoplasty involves expanding the diameter of the foramen at three specific locations to reduce the risk of nerve root damage.

It is effective in relieving foraminal compression and has good long-term outcomes for patients with neurogenic claudication symptoms. The interlaminar approach is preferred for cases involving L5/S1 discs with a high iliac crest.

Advancements in endoscopic spine surgery have expanded its use for more complex discectomy procedures. Modifications to the transforaminal approach have been described, and better equipment has made it possible to use TELD for cases that were previously contraindicated. However, caution should be taken in cases where patients have neurological deficits or cauda equina syndrome.

An endoscopic osteotome has been effective in removing calcified herniations in TELD procedures, and recent studies have shown that TELD can produce good results in treating large prolapsed discs in patients with high canal compromise.

Endoscopic surgery is a better option for patients with recurrent disc herniation due to less scarring and soft tissue trauma. The procedure has been particularly effective for patients under 40 years old, those with symptoms lasting less than 3 months, and those without lateral recess stenosis. Endoscopic surgery has also demonstrated better results compared to open surgery, including shorter operating times, reduced blood loss, fewer complications, better outcomes, and improved pain reduction.

TELD had limitations in treating disc herniations with spinal stenosis due to incomplete symptom resolution. However, TELD can still be used to treat patients with disc herniation and unilateral asymmetrical lateral recess stenosis using an extreme lateral transforaminal approach with foraminoplasty.

Positive clinical outcomes have been reported two years after using this technique. Foraminoplasty directed at the base of the superior articular process can benefit patients with both lateral recess stenosis and disc herniation by reducing neural dysfunction and shortening operative time.

TELD has been used for the removal of facet cysts, discal cysts, and tumors, which are less frequent indications for the procedure. Discal cysts have been treated with TELD and have similar clinical features to herniated intervertebral discs.

TELD has also been employed for treating facet cysts causing lateral recess stenosis, resulting in good clinical outcomes and preserving spinal stability. Tumor debulking has been performed using the transforaminal approach in patients with a low life expectancy, resulting in palliative symptom relief.

The transforaminal approach in endoscopic techniques has advanced and is used for interbody fusion, offering advantages like preserving soft tissue and being performed under local anesthesia.

It’s suitable for patients with spinal instability and significant disc height collapse causing foraminal stenosis, but there are concerns about its limited safety window, and transient neurologic complications and cage subsidence. Literature has shown mixed results with standalone cages in extremely collapsed discs.

Interlaminar Approach

The interlaminar endoscopic approach has gained popularity in treating central and lateral recess stenosis, as well as foraminal stenosis, due to advancements in endoscopic equipment and visualization techniques. It is particularly useful for L5/S1 disc herniation because of the wide interlaminar window.

The approach has three subdivisions, including interlaminar endoscopic lumbar discectomy, interlaminar endoscopic lateral recess decompression, and lumbar endoscopic unilateral laminotomy for bilateral decompression. This technique has become a popular surgical method for discectomy and stenosis decompression.

Doctors at Complete Orthopedics prefer interlaminar endoscopy because they are familiar with interlaminar anatomy from their spine practice. Clinical studies show that interlaminar endoscopic surgery has outcomes similar to traditional open surgery and minimally invasive microscopic tubular surgery but with fewer adverse events and shorter hospital stays. Recent studies suggest that interlaminar endoscopic decompression significantly improves visual analogue scale scores for back and leg pain and the Oswestry Disability Index.

Interlaminar endoscopic techniques can now be used for highly migrated disc herniation, allowing for sequestrectomy to remove migrated disc fragments and prevent subsequent spinal segment instability. The recurrence rate of discectomy is around 1-20%, but annular sealing and reduction of annular defects can decrease the risk of recurrence.

Angled scopes and flexible forceps have enabled removal of sequestrated discs in previously hard-to-access areas, making the surgery viable for less experienced surgeons. However, high canal compromise is a relative contraindication, and gentle handling of neural tissue is necessary during dissection.

Recurrent disc herniation can be challenging to treat with open or endoscopic spine surgery. Revision discectomy and fusion procedures yield similar outcomes. Endoscopic approaches, including transforaminal and interlaminar techniques, result in shorter hospital stays, less blood loss, and a quicker return to work compared to open surgery, while maintaining similar pain and disability scores.

TELD is preferred for revision discectomy due to encountering less scarring than IELD, although IELD can safely explore and perform discectomy even in the presence of significant scar tissue. Endoscopic procedures are less traumatic than open surgery, resulting in less scarring and preservation of soft tissue.

The presence of multiple types of spinal stenosis can lead to severe symptoms in patients, and traditional approaches may have limitations. A new technique called interlaminar contralateral endoscopic lumbar foraminotomy (ICELF) combines paraspinal and interlaminar approaches to safely and effectively decompress all three areas of stenosis using a small working channel and 30° endoscope. This technique allows for no-touch neural decompression and is done in one procedure without the need for multiple approaches.

The uniportal full endoscopic posterolateral TLIF technique is a modified approach to the traditional posterolateral TLIF that safely respects the ipsilateral facet joint with an endoscopic drill.

This technique provides a larger corridor, a safe working region, and a reduced likelihood of exiting nerve root dysesthesia. The technique has been successfully demonstrated in a patient with spondylolisthesis and instability, but further studies are needed to assess its safety and effectiveness.

The paraspinal approach is commonly used for decompression of the nerve root in the foramen and extraforaminal region. It offers the advantage of lower risk of nerve root and cauda equina injury while maintaining facet integrity. However, it has a difficult learning curve and requires careful handling of the dorsal root ganglion and radicular artery.

Injury to the artery can lead to bleeding, hematoma, and may require open surgery. This approach is typically used for treating foraminal and extraforaminal stenosis caused by disc herniation, facet cysts, and foraminal osteophytes.

The paraspinal endoscopic approach can now be used for far-out syndrome, which requires more lateral decompression to access the nerve root existing in the far lateral region. It is particularly beneficial in the L5/S1 region, where the nerve root is compressed between the transverse process of L5, the sacral ala, and/or the bony spur at the extraforaminal region.

The expanding use of endoscopic spine surgery in the lumbar region requires managing complications without open surgery. One such complication is incidental durotomy, which can be addressed through patch-blocking dura repair, using collagen fibrin patches such as Tachosil.

This technique is used in open spine surgery and can also be applied in uniportal and biportal endoscopic surgery. Uniportal endoscopic equipment could eventually allow primary repair, reducing the need for open surgery and enabling surgeons to handle more complex revision cases with greater confidence.

During endoscopic spine surgery, accumulation of fluid in the spinal canal due to improper outflow of irrigation can cause increased cerebrospinal fluid pressure, cerebral edema, seizures, and neurological dysfunction. Epidural suction catheter placement is crucial in open spine surgery to prevent pseudohypoxic brain swelling.

Although less common under local or regional anesthesia due to the presence of neck pain, endoscopic surgeons should pause the procedure if patients report neck pain to allow pressure equilibration. Maintaining good inflow and outflow systems during the procedure with irrigation pressure around 25-30 mmHg is also essential.

The prevention of hematoma formation is essential in endoscopic spine surgery, and careful hemostasis before closing the surgical site is crucial. The surgeon should slowly remove the working channel, visually inspecting the soft tissue and performing hemostasis along the way. A soft suction drain may be used to remove fluids and blood during the first postoperative day if bony drilling and decompression are performed.

Summary of Current and Future Expansions of Indications of Endoscopic Spine Surgery

Endoscopic spine surgery has experienced significant advancements due to the work of pioneers and early adopters, as well as an increase in training courses, fellowships, and peer-reviewed articles. Industry investments are being made to improve equipment and anesthesia techniques. Surgeons must be cautious not to over promise the benefits of endoscopic spine surgery, and be aware of their limitations.

The technique has a steep learning curve, but with practice, up to 90% of uncomplicated lumbar degenerative procedures can be performed. With further refinement and research, endoscopic spine surgery may have wider clinical applications in the future, leading to personalized spine care.

If you are interested in knowing more about development of full-endoscopic lumbar spine surgery conditions you have come to the right place!