Laminectomy and Minimal Invasive Decompression

Spinal stenosis in the lumbar region is a prevalent condition among the growing elderly demographic, causing symptoms such as claudication, back and leg pain, and functional impairment.

The past decade has seen a rise in the frequency of lumbar spine decompression surgeries performed to address lumbar stenosis. The traditional method of decompression involves an open laminectomy procedure, in which the deep paraspinal muscles are stripped and retracted to reveal the lamina during surgery.

Prolonged retraction can result in atrophy of the multifidus muscles and compromised arterial blood supply, potentially leading to chronic low back pain after surgery due to changes in the biomechanics of the ligamentous structures that support the posterior region. The surgical procedure may also harm the fragile posterior dorsal rami and other vulnerable nerve structures.

Microendoscopic procedures have become increasingly popular in recent years as they are designed to reduce invasiveness. Minimally invasive laminectomy involves smaller incisions in an attempt to decrease blood loss, pain, and hospital stay compared to the conventional open laminectomy method.

The primary microsurgical technique utilized has been the unilateral laminectomy for bilateral decompression (ULBD). Although minimally invasive techniques are being used more frequently, there is a scarcity of research that has directly compared their safety, effectiveness, and results with those of conventional laminectomy.

The utilization of minimally invasive laminectomy techniques, including ULBD, is on the rise. The lack of strong clinical evidence to support the safety and efficacy of this technique is not commensurate with its rapid and enthusiastic adoption.

Compared to the open approach, ULBD is linked with a greater percentage of contented patients and lower Visual Analog Scale (VAS) scores.ULBD is a safe procedure that leads to lower blood loss and comparable rates of complications such as dural tears, wound infection, and cerebrospinal fluid (CSF) leakage.

Based on randomized evidence, the likelihood of similar reoperation rates is high. ULBD surgeries take approximately 11 minutes longer than the open approach, but this difference may not have clinical significance. Compared to open laminectomy, ULBD results in a considerably shorter hospitalization period.

While conventional laminectomy is generally viewed as a safe and effective treatment for lumbar spinal stenosis, its overall success rates may vary from 62% to 70%. In addition, secondary spinal instability has been reported as a result of surgical failure.

The invasive nature of the open procedure may be responsible for the negative consequences it may cause, such as spinal muscle atrophy, nerve damage, and disturbance of arteriolar blood supply. During the procedure, the multifidus muscles are retracted bilaterally for extended periods, which may result in muscle atrophy, as evidenced by CT and electromyography of endurance-tested muscles.

Muscle retraction during the procedure may also cause denervation or tethering of the medial branch of the dorsal ramus, which innervates the multifidus. Moreover, the open laminectomy procedure entails the dissection of supraspinous and interspinous ligaments, which typically offer support and stability to the spine through their ligamentous functions.

Flexion instability can be a potential complication of open laminectomy as the procedure involves the removal of supraspinous and interspinous ligaments that play a vital role in providing spinal stability and ligamentous support.

All of these factors may contribute to persistent pain and potentially worsen symptoms in patients with lumbar spinal stenosis, particularly in older patients with multiple spinal levels affected. To address some of the problems associated with open laminectomy, the literature has introduced microendoscopic laminectomy techniques through endoscopic discectomy.

The microsurgical approach of endoscopic discectomy employs a retraction system, tubular dilators, and an endoscope to provide visualization while minimizing damage to soft tissues and maximizing muscle preservation. To be more specific, preserving the parasternal neck muscles during surgery may alleviate postoperative neck pain and dysfunction, especially for cervical spine pathologies. A mini-open incision has been utilized in different versions of this approach.

The specialized operating microscope enables a clear view of important structures such as the spinal canal, nerve root interface, and ligamentum flavum during the procedure. A smaller incision and reduced patient trauma are characteristic of the minimally invasive ULBD procedure.

Some patients who undergo conventional laminectomy may experience postoperative instability and kyphosis due to larger resections of the facet joint, which is not the case with smaller resections seen in minimally invasive ULBD.

ULBD for lumbar stenosis has been associated with several possible drawbacks in prior discussions. ULBD for lumbar stenosis has been associated with some potential drawbacks. One of the concerns is related to limited visualization of crucial structures such as dura and nerve roots.

This can lead to a higher likelihood of accidental durotomy, as claimed by some experts. In a restricted surgical field, high-speed drills can pose a risk of dural tears. The incidence rates of complications such as wound infection were similar between ULBD and conventional laminectomy groups, and were consistent with the general spinal surgery literature’s reported rates of 1.9%.

The second disadvantage of minimally invasive ULBD is that it is a technically challenging and complex procedure that requires a significant amount of experience to decompress neural structures adequately. Additionally, the procedure has a steep learning curve.

The unilateral tubular technique used in ULBD provides a restricted visual field and limited physical space to maneuver surgical instruments. The restricted visual field during surgery may cause confusion and result in incomplete decompression. The ULBD technique may require a longer operation time compared to the conventional approach due to the learning curve associated with the procedure.