Microendoscopic Decompressive Laminotomy Research Articles

Global Trends and Hotspots of Minimally Invasive Surgery in Lumbar Spinal Stenosis: A Bibliometric Analysis.

The popularity of minimally invasive surgery for lumbar spinal stenosis (LSS) has been steadily increasing worldwide. This study aims to conduct a comprehensive bibliometric analysis to identify global trends and hotspots in the research related to this surgical approach. Select articles related to the field that were retrieved from the Web of Science Core Collection (WoSCC) between January 1, 1993 and December 31, 2022. Visualization of networks and in-depth bibliometric analyses, including the number of publications, countries/regions, institutions, journals, authors, keywords, and references, were conducted using VOSviewer and CiteSpace software. A total of 1197 papers were identified over a three-decade period, with the highest production year being 2022, which saw 171 papers published. The most prolific countries/regions were the United States (279) and Harvard Medical School (59). Among journals, Spine (3289 citations) was the most cited, while World Neurosurgery (98 publications) had the highest number of publications. Lewandrowski, Kai-Uwe (29 publications) wrote the most articles, and Ahn, Y (239 citations) ranked first among cited authors. The most frequently used keyword was "discectomy", but recent years have shown a strong emergence of keywords such as "microendoscopic decompressive laminotomy", "foraminotomy" and "classification". The United States and China have emerged as leaders in the field of minimally invasive surgery for LSS. Endoscopic spinal surgery is recognized as a critical approach, with ongoing research focused on indications, potential complications, minimally invasive anatomical approaches, and outcomes. Furthermore, there is a strong emphasis on optimizing the surgical process, which has become a trending and hot spot in current research. The improvement of surgical techniques is at the forefront of advancements in this field.

A new classification for spinal epidural hematoma following microendoscopic decompressive laminotomy: A prospective clinical and magnetic resonance imaging study of 245 patients.

The aim of this study was to develop a new radiological classification system for postoperative spinal epidural hematoma (SEH) using magnetic resonance imaging (MRI) and to determine the correlation of this classification system with clinical and radiological outcomes. This prospective study included a total of 245 consecutive patients (126 females, 119 males; mean age=72 years; age range=39-91 years) with single level spinal stenosis who were treated by microendoscopic decompressive laminotomy (MEDL). MRI was performed for all patients 24 hours postoperatively and at 12 months. SHEs were categorized into four grades using our new MRI-based classification system based on the measurement of dural sac area: Grade A, small hematoma with a round shape; grade B, small hematoma that show no round shape; grade C, moderate hematoma; grade D: severe hematoma. Patients were then divided into four groups according to their hematoma grades, Group A, 107 patients with grade A hematomas; group B, 47 with grade B; group C, 67 with grade C; group D, 24 with grade D. Also, patients who had neurological deterioration or who pain resistant to medical treatment were treated surgically, and those were assigned to group H+(14 patients). The study, therefore, contained five groups. Clinical evaluation was done using Japanese Orthopaedic Association (JOA) score preoperatively and at 12 months postoperatively. No significant difference existed among groups in the preoperative median measurement of the dural sac area, which were 0.90 cm2 in group A, 0.80 cm2 in group B, 0.70 cm2 in group C, 1.1 cm2 in group D, and 0.80 cm2 in group H+ (p=0.076). At the postoperative 12-month measurement, no significant difference was noted among groups A (2.05 cm2), B (1.80 cm2 ), and H+ (1.90cm2) (A vs B: p=0.891, A vs H+: p=0.089, B vs H +: p=0.933). The measurements were greater in groups A and B than in groups C and D (p<0.05). Also, larger dural sac areas were determined in group H+ (1.90cm2) compared to Groups C (1.80 cm2) and D (1.60 cm2) but the difference reached no statistical significance (p=0.078). In preoperative JOA scores, there were no significant differences among groups (p>0.05). At 12-month JOA scores, no significant difference was observed between groups A and B (p=0.061) and between groups C and D (p=0.511). The scores were higher in groups A and B than in groups C and D (p<0.05). It seems that the narrower the preoperative dural sac area, the better the clinical symptoms of the patients with SEHs based on our new MRI-based classification system. This classification may be useful to predict the clinical status of these patients at one-year follow-up. Level IV, Diagnostic study.

Does the drain placement technique affect the amount of postoperative spinal epidural hematoma after microendoscopic decompressive laminotomy for lumbar spinal stenosis?

To prospectively evaluate with magnetic resonance imaging (MRI), the relationship between the distance from the incision of the drain output location and postoperative spinal epidural hematoma (SEH) in patients performed with microendoscopic decompressive laminotomy (MEDL) for lumbar spinal stenosis. Between January 2016 and June 2018, three different kinds of drain placement techniques, according to the drain output location, were performed to a total of 184 patients after MEDL for single-level spinal stenosis. The location of the drain output was within the incision in group 1, 1 cm lateral of the incision in group 2, and 5 cm lateral of the incision in group 3. At 24 h postoperatively, before removal of the drain, MRI examination was carried out in patients. A specific classification was developed by the authors to measure SEH, and the groups were evaluated by comparison. The mean postoperative dural sac cross-sectional area was 1.73 cm2 (standard deviation (SD): 0.711) in group 1, 1.66 cm2 (SD: 0.732) in group 2, and 1.52 cm2 in group 3 (SD: 0.841).The mean cross-sectional area of the postoperative hematoma was 1.45 cm2 (SD: 1.007) in group 1, 1.57 cm2 (SD: 1.053) in group 2, and 2.11 cm2 (SD: 1.024) in group 3. Four grades were defined according to the specific classification. According to this classification, grades C and D postoperative hematomas were determined at a statistically significantly higher rate in group 3 patients (drain output 5 cm lateral from the incision) compared to the other groups (p = 0.000). No significant difference was determined between groups 1 and 2 in respect of hematoma classification. In conclusion, it was determined that better drainage was provided in groups 1 and 2, where the drain output location was in the incision or close to it.

A New Angled Chisel for Microendoscopic Decompressive Laminotomy.

A retrospective comparative series study. The aim of the study was to describe a new angled chisel (NAC) that facilitates the osteotomy in microendoscopic decompressive laminotomy (MEDL), and to analyze the clinical and radiologic outcomes using the tool. MEDL for lumbar spinal stenosis is a minimally invasive surgery. The paraspinous unilateral approach for bilateral decompression can preserve the posterior structure better than other methods. However, the resection of the medial facet on the approach side is technically difficult because the working space is limited and the retractor is difficult to place properly. Because of these limitations, either the inferior articular process on the approach side tends to be resected excessively, which can lead to facet fracture and instability, or the superior articular process tends to be resected insufficiently, which can result in residual symptoms. The ideal decompression of the medial facet consists of sufficient resection to the deep portion, especially lateral recess of the spinal canal, and adequate facet preservation. Special curved devices to obtain optimal resection have been developed, but these devices have not effectively improved the osteotomy. We developed an NAC to allow an osteotomy at the desired angle. Forty patients underwent MEDL with the use of NAC (NAC group) and 40 patients underwent the same procedure without the NAC (control group). The osteotomy angle of the medial facet on the approach side and Visual Analogue Scale score were analyzed. The average osteotomy angle of the medial facet was significantly smaller in the NAC group. The radiologic and clinical results were significantly better in the NAC group. The NAC was a useful tool that sharpens the osteotomy angle of the medial facet and thereby improved the clinical course.

Urokinase-Treated Antithrombogenic Drains and Optimized Drain Placement in Endoscopic Lumbar Decompressive Surgery.

Background Spinal epidural hematoma (SEH) frequently occurs after microendoscopic decompressive laminotomy (MEDL), and a drain may not be functioning sufficiently. Objective To reduce the incidence of SEH after MEDL. Methods A urokinase-treated antithrombogenic drain, which is available only with a large diameter, was reduced in diameter and used after MEDL. Magnetic resonance imaging (MRI) and computed tomography (CT) were performed 36 to 48 hours after surgery. The size of the SEH was measured by MRI, and the location of the drain tip was assessed by CT scan. After imaging, the drain was removed. Results Use of the urokinase-treated antithrombogenic drain reduced the incidence of SEH. However, the drain was not adequately placed in many cases, limiting the effect of the drainage. When the urokinase-treated antithrombogenic drain was placed contralaterally to the approach side using an unsheathed endoscope, the incidence of SEH was further reduced. Conclusions The urokinase-treated antithrombogenic drain prevented thrombus-related drain obstruction. In addition, unsheathed endoscopic contralateral placement of the drain was effective for SEH prevention.

Patient outcomes for a minimally invasive approach to treat lumbar spinal canal stenosis: Is microendoscopic or microscopic decompressive laminotomy the less invasive surgery?

ObjectiveWe performed a study to compare the severity of surgical stress between microscopic and microendoscopic decompressive laminotomy performed via a unilateral approach in patients with lumbar spinal canal stenosis (LSCS). Materials and methodsA total of 41 patients received decompressive laminotomy for lumbar spinal stenosis. Twenty patients received microscopic decompressive laminotomy (MDL), and 21 patients received microendoscopic decompressive laminotomy (MEDL). The pre- and postoperative Japanese Orthopaedic Association (JOA), and Visual Analogue Scale (VAS) lower leg pain scores were evaluated. The other variables studied were the length of the operation, blood loss, length of hospital stay, the reaction of the CRP and WBC levels, the dosage of non-steroidal anti-inflammatory drugs (NSAIDs) used and surgical complications. ResultsThe clinical analyses of the surgical outcomes were evaluated after a minimum two-year follow-up. The pre-and postoperative JOA scores and VAS in the MDL and MEDL groups were statistically similar. There were statistically significant differences found between the lengths of the operation time, blood loss, length of hospital stay, the reaction of CRP, and the pain indicated by the dosage of NSAIDs. The length of the operation time was longer in the MEDL group, and the other variables were greater in the MDL group. ConclusionsThe MEDL procedure is less invasive and safer than the MDL procedure. Hence, MEDL is an effective technique for treating symptomatic LSCS patients.

Clinical significance of postdecompression facet joint effusion after minimally invasive decompression for degenerative lumbar spinal stenosis.

A retrospective case series study. To investigate the clinical significance of postdecompression facet effusion (PDFE) after microendoscopic decompressive laminotomy (MEDL). The facet joint effusion noted on magnetic resonance imaging was considered as an indicator of degeneration of the facet joints and segmental instability. PDFE occurring after MEDL might imply postdecompression segmental instability. Its clinical significance has not yet been clarified. From 2005 to 2010, 165 patients with degenerative lumbar spinal stenosis (average age: 64.5, average follow-up: 25.8 mo) who received MEDL were reviewed. We investigated the incidence of PDFE with preoperative and repetitive magnetic resonance imaging at 6 months postoperatively. The clinical data and treatment courses were reviewed. The treatment outcomes were evaluated with Oswestry Disability Index and Japanese Orthopedic Association scores. The incidence of PDFE was 17.0% (n=28), which was significantly higher in patients receiving multilevel decompression and patients with scoliosis or spondylolisthesis. The intensity of low back pain was similar between patients with and without PDFE, but "mechanical" low back pain was only noted in patients with PDFE. Of the 28 patients with PDFE, only 9 symptomatic patients required invasive treatment (5 facet joint steroid injection, 3 revision MEDL, and 1 spinal fusion). Although the postoperative Oswestry Disability Index and Japanese Orthopedic Association scores were significantly worse these 9 patients, the final outcomes were good. Progression of spondylolisthesis was noted in 2 patients without PDFE but no patients with PDFE during the follow-up period. The relatively high incidence of PDFE after MEDL suggests that injury to the integrity of facet joint is inevitable during decompression of the stenosis, even using minimally invasive techniques. However, the overall stability is well preserved with very rare progression of spondylolisthesis. Most patients with PDFE are asymptomatic. The prognosis of PDFE is very good. Spinal fusion is rarely indicated.

Intraoperative Myelography in Minimally Invasive Decompression for Degenerative Lumbar Spinal Stenosis

A retrospective comparative series study. To develop an intraoperative myelography protocol and determine its value on the treatment results in microendoscopic decompressive laminotomy (MEDL) for degenerative lumbar spinal stenosis. The MEDL is a minimally invasive but technically demanding technique for decompressing spinal stenosis. An intraoperatively assessing method for adequate decompression is lacking, but may be helpful and has positive value on the treatment results. Forty consecutive degenerative lumbar spinal stenosis patients receiving MEDL were included in this study. The earlier 20 patients received MEDL without myelography (the traditional group); the later 20 patients received MEDL with the myelography protocol (the myelography group). An additional intraoperative myelography was performed in the myelography group to help localizing the stenosis before decompression and verifying adequate decompression after decompression. Any residual filling defects identified in the postdecompression myelogram were considered signs of inadequate decompression and additional decompression was performed until they resolved. Inadequate decompression was identified in 4 of 20 patients in the myelography group, but none in the traditional group. Both groups had significant improvement after surgery. However, the myelography group had significantly better results with lower 6-month Oswestry Disability Index (ODI) (6 vs. 10, P=0.049), more ODI improvement (44 vs. 28, P=0.009), higher Japanese Orthopedic Association (JOA) scores (27.5 vs. 24, P=0.043), a higher JOA improvement rate (92.8% vs. 73.2%, P=0.013), and greater decompression effect (56.8% vs. 41.4% cross-sectional dural area, P=0.024). The myelography group also had a higher proportion of patients to have "significant ODI improvement," "JOA success," and "JOA good-to-excellent results." There were no myelography-related complications. The intraoperative myelography protocol provides a simple method to precisely localize the stenosis and verifies the adequacy of decompression; hence, improves the treatment result of MEDL.

Clinical Outcome of Microsurgical Bilateral Decompression via Unilateral Approach for Lumbar Canal Stenosis

Study Design. A retrospective study. Objective. To evaluate minimum 5-year clinical outcome and radiologic changes in patients who underwent microsurgical bilateral decompression via a unilateral approach. Summary of Background Data. Some authors have reported satisfactory short-term results of minimally invasive decompressive procedures such as microscopic or microendoscopic decompressive laminotomy for lumbar spinal stenosis (LSS). However, there have been a few reports on the long-term clinical outcome of these procedures. Methods. The study consisted of 57 patients who underwent this surgery and had been followed for at least 5 years. The preoperative diagnoses were LSS without instability in 27 patients, degenerative lumbar spondylolisthesis (DS) in 20 patients, and degenerative lumbar scoliosis (DLS) in 10 patients. The mean duration of follow-up was 6 years. Clinical outcome was evaluated by Japanese Orthopedic Association (JOA) score. Complications, rate of reoperation, and radiographic changes after surgery on plain radiograph were evaluated. Results. The mean JOA score was 13.8 ± 3.6 points before surgery, and improved to 24.9 ± 3.1 points at 3 months and 22.6 ± 4.7 points at the latest follow-up. There were no significant differences in JOA score at the latest follow-up among patients with LSS, DS, and degenerative scoliosis (22.3 ± 5.3, 23.3 ± 4.4, and 21.6 ± 2.6, respectively). Four patients (7%) underwent reoperation; 2 had DS and 2 had DLS. The preoperative percentages of slippage in patients with LSS, DS, and DLS were 0.4% ± 2.2%, 13.2% ± 5.9%, and 0.0% ± 1.3%, respectively, whereas degrees of progression of slippage at latest follow-up were 1.2% ± 3.1 %, 2.4% ± 4.7%, and 0.0% ± 0.0%, respectively. There were no significant differences in progression of slippage among these 3 disease groups. Conclusion. Microsurgical bilateral decompression via a unilateral approach is a minimally invasive technique that yielded satisfactory surgical outcomes even on minimum 5-year follow-up.

Treatment of lateral recess stenosis by means of microendoscopic decompressive laminotomy results at one year

Purpose To determine the efficacy of microendoscopic root decompression in lumbar lateral recess stenosis. Materials and methods Prospective longitudinal study of 60 patients diagnosed with lumbar canal stenosis and subjected to microendoscopic decompression by means of a METRx 18 mm tubular retractor following the METRx (Medtronic Sofamor Danek, Memphis, TN, U.S.A.) technique. Results were evaluated using the visual analog scale (VAS) for pain measurement, the Oswestry Disability Index (ODI), subjective patient satisfaction and McNab's modified score. Results Mean age was 54.5±10 years. Thirty-four patients (56.7%) were male and 26 (43.3%) female. The most frequently affected level was L5 (63.33%). Mean OR time was 85.17±18 minutes. Mean postoperative length of hospital stay was 4±1.2 days. Patient follow-up was 12 months. We obtained 66.6% good or excellent results with 68.3% of patients claiming to be satisfied with their outcome. Mean decrease on ODI at one year, as compared with the preoperative ODI score, was 34.3±26.2 points. Decrease on the VAS score was 6.2±2.6 points for the lower limbs and 1.6±1.8 points for the lumbar spine. All these magnitudes were statistically significant (p<0.05). Conclusions The data collected from the study indicate that microendoscopic decompressive laminotomy is a safe and effective technique for treating lumbar lateral recess stenosis, which should feature prominently among the surgeon's procedures of choice for minimally invasive spine surgery.

Clinical outcomes of microendoscopic decompressive laminotomy for degenerative lumbar spinal stenosis

The goal of surgical treatment for degenerative lumbar spinal stenosis (LSS) is to effectively relieve the neural structures by various decompressive techniques. Microendoscopic decompressive laminotomy (MEDL) is an attractive option because of its minimally invasive nature. The aim of prospective study was to investigate the effectiveness of MEDL by evaluating the clinical outcomes with patient-oriented scoring systems. Sixty consecutive patients receiving MEDL between December 2005 and April 2007 were enrolled. The indications of surgery were moderate to severe stenosis, persistent neurological symptoms, and failure of conservative treatment. The patients with mechanical back pain, more than grade I spondylolisthesis, or radiographic signs of instability were not included. A total of 53 patients (36 women and 17 men, mean age 62.0) were included. Forty-five patients (84.9%) were satisfied with the treatment result after a follow-up period of 15.7 months (12-24). The clinical outcomes were evaluated with the Oswestry disability index (ODI) and the Japanese Orthopedic Association (JOA) score. Of the 50 patients providing sufficient data for analysis, the ODI improved from 64.3 +/- 20.0 to 16.7 +/- 20.0. The JOA score improved from 9.4 +/- 6.1 to 24.2 +/- 6.0. The improvement rate was 73.9 +/- 30.7% and 40 patients (80%) had good or excellent results. There were 11 surgical complications: dural tear in 5, wrong level operation in 2, and transient neuralgia in 4 patients. No wound-related complication was noted. Although the prevalence of pre-operative comorbidities was very high (69.8%), there was no serious medical complication. There was no post-operative instability at the operated segment as evaluated with dynamic radiographs at final follow-up. We concluded that MEDL is a safe and very effective minimally invasive technique for degenerative LSS. With an appropriate patient selection, the risk of post-operative instability is minimal.

Microendoscopic Decompressive Laminotomy for the Treatment of Lumbar Stenosis

By modifying existing microendoscopic discectomy techniques, we previously developed a novel surgical treatment of lumbar stenosis and validated its ability to achieve a thorough decompression in a cadaveric study. We now describe our clinical experience with this new, minimally invasive microendoscopic decompressive laminotomy (MEDL) technique. A MEDL was performed in 25 patients with classic features of lumbar stenosis. By use of a fluoroscopically guided percutaneous technique, the working portal was docked on the lamina with minimal soft-tissue injury. With the angle of the endoscope combined with an oblique entry, a bilateral bony and ligamentous decompression was achieved under the midline, thereby preserving the supraspinous-interspinous ligaments and contralateral musculature. A second group of 25 patients treated with open decompression was used for comparison. Effective circumferential decompression was achieved in the majority of patients. The results for the MEDL group were as follows: operative time, 109 minutes per single level; blood loss, 68 ml; and postoperative stay, 42 hours. The results for the open-surgery group were as follows: operative time, 88 minutes; blood loss, 193 ml; and postoperative stay, 94 hours. The MEDL group needed significantly less narcotic medication after surgery. Overall, 16% of the MEDL patients reported resolution of their back pain, 68% improved symptomatically, and 16% remained unchanged. The outcome of the open group was very similar. Compared with an equivalent open technique, MEDL appears to offer a similar short-term clinical outcome with a significant reduction in operative blood loss, postoperative stay, and use of narcotics. This lower surgical stress, decreased tissue trauma, and quicker recovery are particularly important in this elderly population of patients.