Microendoscopy-assisted extraforaminal lumbar interbody fusion for treating single-level spondylodesis.

BACKGROUND: Lumbar interbody fusion is a standard technique for treating degenerative lumbar disorders involving instability. Due to its invasiveness, a minimally invasive technique, extraforaminal lumbar interbody fusion (ELIF), was introduced. On surgically approaching posterolaterally, the posterior muscles and spinal canal are barely invaded. Despite its theoretical advantage, ELIF is technically demanding and has not been popularised. Therefore, we developed a microendoscopy-assisted ELIF (mELIF) technique which was designed to be safe and less invasive. Here, we aimed to report on the surgical technique and clinical results. METHODS: Using a posterolateral approach similar to that of lateral disc herniation surgery, a tubular retractor, 16 or 18 mm in diameter, was placed at the lateral aspect of the facet joint. The facet joint was partially excised, and the disc space was cleaned. A cage and local bone graft were inserted into the disc space. All disc-related procedures were performed under microendoscopy. The spinal canal was not invaded. Bilateral percutaneous screw-rod constructs were inserted and fixed. RESULTS: Fifty-five patients underwent the procedure. The Oswestry Disability Index and visual analogue scale scores greatly improved. Over 90% of the patients obtained excellent or good results based on Macnab's criteria. There were neither major adverse clinical effects nor the need for additional surgery. CONCLUSIONS: mELIF is minimally invasive because the spinal canal and posterior muscles are barely invaded. It produces good clinical results with fewer complications. This technique can be applied in most single-level spondylodesis cases, including those involving L5/S1 disorders.

Clinical Comparison of Unilateral Biportal Endoscopic Laminectomy versus Microendoscopic Laminectomy for Single-Level Laminectomy: A Single-Center, Retrospective Analysis.

BACKGROUND: The purpose of this study was to compare clinical results of microendoscopic laminectomy (MEL) with those of unilateral biportal endoscopic laminectomy (UBEL) in patients with single-level lumbar spinal canal stenosis. METHODS: The subjects consisted of 181 patients who underwent MEL (139 cases) and UBEL (42 cases) who were followed up for at least 6 months. All patients had lumber canal stenosis for 1 level. Outcomes of the patients were assessed with the duration of surgery, the bone resection area in 3-dimensional computed tomography, the facet preservation rates in computed tomography axial imagery, Visual Analog Scale (VAS) for low back pain, the Oswestry Disability Index, and the EuroQol 5-Dimensions questionnaire. RESULTS: The bone resection area in 3-dimensional computed tomography was 1.5 for MEL versus 1.0 cm2 for UBEL (P < 0.05). The facet preservation rates on the advancing side and the opposite side were 78% versus 86% (advancing side: MEL vs. UBEL) and 85% versus 94% (opposite side) (P < 0.05). The VAS (low back pain) score, VAS (leg pain), Oswestry Disability Index, and EuroQol 5-Dimension questionnaire significantly dropped in both groups at the final period (P < 0.05), however, exhibiting no difference between the 2 groups at each period. MEL resulted in greater numbers of complications, including 5 cases of hematoma paralysis, 8 cases of dura injury, 2 cases of reoperation, as opposed to zero cases of hematoma paralysis and only 2 cases of dura injury resulting from UBEL. CONCLUSIONS: The UBEL method is a more useful technique than the MEL method as it requires a smaller bone resection area and produces fewer complications.

Does "Coronal Root Angle" Serve as a Parameter in the Removal of Ventral Factors for Foraminal Stenosis at L5-S1 In Stand-alone Microendoscopic Decompression?

STUDY DESIGN: Prospective single-center cohort study. OBJECTIVE: The present study aims to investigate the causes of failure of L5/S1 foraminal stenosis, and it is hypothesized that the newly defined "L5 coronal root angle (CRA)" may be a parameter in the removal of ventral pathologies. SUMMARY OF BACKGROUND DATA: Lumbar foraminal stenosis is an important cause of recurrent leg pain after central spinal stenosis surgery. Although it can be seen at all levels, L5/S1 is the level at which it is most frequently seen due to its specific characteristics, with success rate is lower than other levels after foraminal decompression. METHODS: L5/S1 microendoscopic foraminal decompression was performed to 51 patients. According to Japanese Orthopedic Association (JOA) improvement at 12-month follow-up, those with improvement >20% were classified as Group 1 and <20% were classified as Group 2. The patients who underwent discectomy in addition to foraminotomy formed Group 3. Lumbar lordosis angle, segmental lordosis angle, anterior disc height, pelvic tilt, pelvic incidence, sacral slope, relative disc height ratio, pedicle height/vertebral body height ratio, L5 depth, L5 CRA, and anterior disc height/ posterior disc height ratio parameters were measured with lumbar radiographic views, computed tomography (CT), and magnetic resonance imaging (MRI). RESULTS: Among the parameters compared between groups, L5 CRA, posterior disc height, anterior disc height/posterior disc height, relative disc height ratio, and lumbar lordosis angle during extension were seen to be statistically significantly related with low success rate. CONCLUSION: Failure to remove the ventral pathologies when the L5 CRA is <112. 1º may lead to failed results. Besides, in cases wherein the posterior disc height is <2.85 mm or the anterior/posterior disc height ratio is >3.98, approaches to restoring disc height rather than stand-alone posterior decompression may reduce the possibility of failure. LEVEL OF EVIDENCE: 2.

Postoperative Outcomes After Transsacral Epiduroscopic Laser Decompression in Japanese Patients: Denervation Therapy for Discogenic Low-Back Pain.

Background: Transsacral epiduroscopic laser decompression (SELD) is a very noninvasive surgery, so it is effective for elderly patients and athletes and is a new and minimally invasive therapeutic technique that may be useful in many patients with discogenic low-back pain (LBP) having high signal intensity zone (HIZ) in magnetic resonance imaging (MRI). We investigated the clinical outcomes of SELD in Japanese patients with discogenic LBP having HIZ as a first trial. Methods: The subjects consisted of 52 patients who underwent SELD and were followed up for at least 6 months. All patients with LBP with HIZ were operative using the SELD technique. Outcomes of the patients were assessed with visual analogue scale (VAS) for LBP, the Oswestry disability index (ODI), and the EuroQol 5 dimension (EQ-5D). Statistical analyses were carried out using a paired t-test. A p-value of <0.05 was considered significant. For statistical analysis, we used the SPSS software program. Results: At 12 months after the procedure, the average VAS score for LBP fell to 1.2 from 5.6 (p-value <0.05). The ODI score also dropped from the preoperative level of 22.3 to 8.8. The EQ-5D score also significantly increased from the preoperative level of 0.865 (SD 0.10) to 0.950 (SD 0.05). Eight cases of intraoperative cervical pain were observed as complications with no cases of hematomas, infections, and postoperative neurosis was observed. Conclusions: SELD provides a novel minimally invasive technique capable of performing multilevel intervertebral surgery. We believe that SELD is an effective method of treating discogenic LBP due to HIZs.

Comparison of Radiation Exposure Among 3 Different Endoscopic Diskectomy Techniques for Lumbar Disk Herniation.

BACKGROUND: Lumbar disk herniation can be successfully treated by lumbar endoscopic spinal procedures. However, one of the most important disadvantages of the endoscopic methods used is radiation exposure. There are multiple endoscopic spinal procedures and this study aims to compare unilateral biportal endoscopic diskectomy (UBED), percutaneous endoscopic lumbar diskectomy (PELD), and microendoscopic diskectomy (MED) methods in terms of radiation exposure. METHODS: A total of 75 people were included in this prospective and multicenter study. The demographic characteristics, operating times (minutes), levels of surgery, lumbar disk herniation types, radiation exposures (dose area product [DAP]), and fluoroscopy times (seconds) of the groups were compared. RESULTS: Mean DAP values were 1.39 Gy·cm2 in the UBED group, 2.46 Gy·cm2 in the PELD group, and 1.01 Gy·cm2 in the MED group. The UBED group had no statistically significant difference with the MED and PELD groups in terms of DAP (P = 0.281 and P = 0.058, respectively), whereas the PELD group had statistically significantly higher DAP values than the MED group (P = 0.016). The maximum mean duration of fluoroscopy usage time was 34.9 seconds in the PELD group, 19.3 seconds in the UBED group, and 4.6 seconds in the MED group. The differences between the groups were significant (P ≤ 0.001). CONCLUSIONS: The more the level of invasiveness is reduced in spinal surgery, the greater the exposure to radiation. In this study, the groups are listed as PELD > UBED > MED according to the duration and level of radiation exposure.

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

OBJECTIVE: 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. METHODS: 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. RESULTS: 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). CONCLUSION: 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 OF EVIDENCE: Level IV, Diagnostic study.

Methods and Early Clinical Results of Percutaneous Lumbar Interbody Fusion.

OBJECTIVE: Percutaneous lumbar interbody fusion (PELIF) is a procedure that includes the use of new devices, which allow minimally invasive diskectomy under the percutaneous full-endoscopic guidance and safe percutaneous insertion of a standard-sized cage. This procedure can be applied to severe disk degeneration, spondylolisthesis, and all lumbar intervertebral levels including the L5-S1 level. We report the methods and the clinical outcomes of this procedure. METHODS: Percutaneous diskectomy was performed with an outer sheath cutter and other devices. A cage was inserted with an L-shaped retract-slider. Hybrid facet screw fixation was performed for severe disk degeneration without spondylolisthesis. Conventional percutaneous pedicle screw fixation was performed for spondylolisthesis. The subjects consisted of 21 patients, who underwent PELIF and were followed up for 1 year or longer. RESULTS: No complications related to cage insertion were detected. The mean visual analogue scale scores were improved from 6.1 to 1.9 for lower back pain in severe disc degeneration cases without spondylolisthesis, and from 7.6 to 1.0 for lower extremity symptoms in spondylolisthesis cases. CONCLUSION: The clinical outcomes were favorable. PELIF was found to be a minimally invasive method that did not compromise safety and efficiency. PELIF is a possible therapeutic option that should be considered for not only spondylolisthesis at various intervertebral levels but also for severe disk degeneration because of its minimal invasiveness.

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

OBJECTIVE: 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. METHODS: 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. RESULTS: 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. CONCLUSION: 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.

Step-by-Step Sublaminar Approach With a Newly-Designed Spinal Endoscope for Unilateral-Approach Bilateral Decompression in Spinal Stenosis.

OBJECTIVE: Spinal stenosis is increasingly common due to population aging. In elderly patients with lumbar central canal stenosis (LCCS), minimizing muscle damage and bone resection is particularly important. We performed a step-by-step operation with a newly designed spinal endoscope to obtain adequate decompression in patients with spinal stenosis. METHODS: From April 2015 to August 2016, 78 patients (48 males, 30 females) with LCCS (91 segments) underwent endoscopic decompression using a newly designed endoscope system. The inclusion criteria were: (1) neurogenic intermittent claudication with or without radiculopathy, (2) LCCS, and (3) having exhausted conservative treatment (>3 months). The exclusion criteria were: (1) >10° of instability, (2) spondylolisthesis grade II or greater according to the Meyerding criteria, (3) foraminal stenosis, (4) vascular intermittent claudication, (5) infection, and (6) stenosis combined with malignancy. We performed a step-by-step procedure using a newly designed endoscope system for unilateral-approach bilateral decompression. We used the same incision for 2-3 segments, only moving the skin. RESULTS: The mean follow-up was 2.3±1.3 years. Excellent or good results were found according to the MacNab criteria in 85.9% of cases (67 of 78). The visual analogue scale, Japanese Orthopedic Association score, and Oswestry Disability Index showed significant decreases at 1 month, persisting until the 2-year follow-up. Dural tear occurred in 4 cases (5.1%), and patch repair was performed under endoscopy. No patients experienced aggravated instability requiring surgery. CONCLUSION: We obtained good results with endoscopic decompression surgery using a newly designed instrument that minimized muscle and bone damage in elderly patients with spinal stenosis.

A New Angled Chisel for Microendoscopic Decompressive Laminotomy.

STUDY DESIGN: A retrospective comparative series study. OBJECTIVE: 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. SUMMARY OF BACKGROUND DATA: 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. MATERIALS AND METHODS: 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. RESULTS: 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. CONCLUSIONS: The NAC was a useful tool that sharpens the osteotomy angle of the medial facet and thereby improved the clinical course.

Rectangular Tubular Retractor for Microendoscopic Lumbar Decompression.

Background A cylindrical working tube with a diameter of 16 mm has been used for endoscopic posterior lumbar spinal surgery. However, intraoperative muscle resection is significant when using the current conventional tubular retractor. Objective To describe a novel tubular retractor for microendoscopic surgery and to analyze the outcomes of lumbar decompressive laminotomy using this retractor. Materials and Methods We devised a novel tubular retractor by changing the medial and lateral sides of the conventional 16-mm cylindrical tubular retractor to planes with a mediolateral dimension of 10 mm (rectangular tubular retractor hereafter). The amount of muscle resection, osteotomy angle on the approach side, and operating time were compared between 25 intervertebral levels treated by bilateral decompression through a unilateral approach using the rectangular tubular retractor and 31 intervertebral levels treated with the same surgery using a 16-mm cylindrical tubular retractor. Results Due to the short mediolateral dimension, muscle resection decreased by 86%. The rectangular tubular retractor also decreased early postoperative wound pain. Because the craniocaudal dimension of the tubular retractor was maintained, surgical difficulty did not increase, resulting in only a slight increase in operating time. The facet joint on the approach side could be sufficiently preserved. Conclusions The rectangular tubular retractor reduced surgical invasiveness without increasing surgical difficulty.

New needle biopsy technique for lumbar pyogenic spondylodiscitis.

STUDY DESIGN: Case series. OBJECTIVE: To improve the isolation rate for pyogenic spondylodiscitis, we developed a new needle biopsy technique. SUMMARY OF BACKGROUND DATA: The biggest problem in treating lumbar pyogenic spondylodiscitis is a low success rate in isolating a causative microorganism. The rates have been reported 42% to 64%. METHODS: There are 3 steps: (A) Insert a 21-G needle as for discography, aspirate pus or fluid as specimen. (B) If step A fails, inject saline and collect fluid as reflux. (C) If step B fails, insert another needle into the disc, inject saline and collect reflux from the other needle. We applied this approach to 12 patients with a mean age of 64.3 years. RESULTS: We were able to collect fluid samples in all cases and the culture was positive in 11 cases (91.6%). Staphylococcus aureus was the most frequently identified organism (41.7%). CONCLUSION: This simple method improved the isolation rate and should improve the treatment of lumbar pyogenic spondylodiscitis.

The relationship between magnetic resonance imaging and quantitative electromyography findings in patients with compressive cervical myelopathy.

STUDY DESIGN: A retrospective comparison of magnetic resonance imaging (MRI) and quantitative electromyography (EMG) findings in patients with compressive cervical myelopathy (CCM). OBJECTIVES: To investigate which parameters of the EMG motor unit potentials (MUPs) as determined by automatic analysis of 4 muscles in the upper limb are correlated with spinal cord compression observed on MRI in CCM patients and to determine whether electrical and radiologic levels are correlated. SUMMARY OF BACKGROUND DATA: Increased mean duration of MUPs has been reported to be a sensitive indicator of disorders of the spinal motor neurons that are accompanied by axonal degeneration and regeneration. METHODS: MRI findings at each cervical disc level from C3/C4 to C6/C7 and MUPs recorded from 4 muscles (deltoid, biceps brachii, triceps brachii, and abductor digiti minimi) were examined to determine whether there is a statistical correlation between spinal cord compression and abnormal parameters of the MUPs for any combination of disc level and muscle. RESULTS: Significant correlations between increased mean duration of MUPs and radiologic level of cord compression were observed for deltoid and cord compression at C3/C4 (P < 0.01), biceps brachii and cord compression at C3/C4 (P < 0.001) and C4/C5 (P < 0.01), triceps brachii and cord compression at C5/C6 (P < 0.05), and abductor digiti minimi and cord compression at C6/C7 (P < 0.001). Other parameters of MUPs including amplitude, polyphasia and denervation potentials did not show significant correlation with compressive spinal cord lesions on MRI. CONCLUSION: Quantitative analysis of mean duration of MUPs provides a reliable indicator of physiologic disorder of spinal motor neurons in CCM and may contribute to establishing the site of motor neuron compromise in cases with multilevel spinal canal stenosis.