This retrospective study involved 450 consecutive cases of degenerative lumbar stenosis treated with percutaneous stenoscopic lumbar decompression (PSLD).
We determined the feasibility of PSLD for lumbar stenosis at single and multiple levels (minimum 1-year follow-up) by image analysis to observe postoperative widening of the vertebral canal in the area.
The decision not to perform an endoscopic decompression might be due to the surgeon being uncomfortable with conventional microscopic decompression or unfamiliar with endoscopic techniques or the unavailability of relevant surgical tools to completely decompress the spinal stenosis.
The decompressed canal was compared between preoperative controls and postoperative treated cases. Data on operative results, including length of stay, operative time, and surgical complications, were analyzed. Patients were assessed clinically on the basis of the Visual Analog Scale (VAS) score for the back and legs and using the Oswestry Disability Index (ODI).
Postoperative magnetic resonance imaging revealed that PSLD increased the canal cross-sectional area by 52.0% compared with the preoperative area at the index segment (
PSLD could be an alternative to microscopic or microendoscopic decompression with various advantages in the surgical management of lumbar stenosis.
Degenerative changes in spine structures, including discs, ligamentum flavum, and facet, lead to spinal stenosis [
This retrospective study was exempted from institutional review board of Good Doctor Teun Teun Hospital. And the informed consent was waived. We studied 450 lumbar stenosis patients (532 disc levels; 254 males, 196 females; mean age, 67.1 years) with central and/or lateral recess stenosis who underwent consecutive bilateral decompression using PSLD at a spine-specialized hospital between April 2016 and December 2016. All patients had symptoms of back pain and bilateral neurogenic claudication with lumbar stenosis (magnetic resonance imaging [MRI] evidence) and underwent at least 3 months of conservative treatment. Patients presenting with foraminal stenosis, combined lesion with disc herniation, or more than grade 1 degenerative spondylolisthesis were excluded from this study. The level of stenosis was L4–5 in 139 patients, L5–S1 in 159, L3–4 in 52, L2–3 in 28, L1–2 in 10, 2-level in 42, and 3-level in 20 (
We evaluated the size of the lamina and facet angle in patients with lumbar stenosis to build up a baseline data set to design an optimal endoscopic procedure for lumbar stenosis. Endoscopy with a suitable outer diameter instrument was expected to minimize further iatrogenic muscle injury and avoid destabilization of bony structures while approaching the lesion. According to mean values of laminar size and facet angle measured in the lumbar stenosis, the lamina size (distance from spinous process to medial margin of facet) was <11 mm for L5 and 9 mm for L3 with a steady decrease in facet angle from L5 to L3 (
The procedure was performed with the patient under epidural anesthesia and placed in a prone, comfortable position on a radiolucent table. The incision location was confirmed by intraoperative fluoroscopy. After making a 7 mm vertical skin incision, a blunt dilator that served as a guide for the 9.5 mm outer diameter working sleeve was advanced into the lamina on the ipsilateral side in a right-angle direction, just beside the spinous process. Subsequently, the working sleeve was inserted over the dilator and a rigid angle stenoscope (8.4 mm outer diameter, 12° view) was introduced into the lesion from one side through the working sleeve. The unique surgical approach through fatty atrophy between the spinous process and multifidus muscles helped to decrease the postoperative muscle-origin back pain and is considered an advantage of this process (
All patients underwent a postoperative MRI. Sagittal and axial T2-weighted images on postoperative day 1 were compared with preoperative images to assess the changes in cross-sectional area (
Mean operating time was 32.3±15.25, 64.4±37.3, and 95.5±28.6 minutes for bilateral decompression at 1, 2, and 3 levels, respectively. Vital signs during the procedures with epidural anesthesia were stable, and all patients had negligible blood loss with no clinical significance. Mean hospital stay was 1.42, 1.47, and 1.50 days, respectively. There was no significant difference in hospitalization between each group (
Postoperative MRI shows a statistically significant increase in cross-sectional area in each segment, with the largest increase in the middle segment (
The mean VAS score for back pain showed a statistically significant improvement from 6.24 preoperatively to 2.36 at 3 months for the 1-level and multiple-level decompression groups (
Of the 450 patients, 13 (2.9%) experienced symptomatic complications associated with PSLD. Four patients (0.9%) required repeat PSLD within 6 weeks postoperatively due to incomplete decompression of the traversing root and postoperative hematoma. Dural tears during procedures were observed in seven patients (1.6%) including two cases of root injury. Open microscopic laminectomy and fusion were done in two patients (0.4%) due to rootlet herniation through the dural defect. There was no significant neurologic deficit of nerve root injury, but one patient had temporary leg dysesthesia. One patient with dural tears complained of a headache for 1 month postoperatively. Only one patient suffered from postoperative infection (
Our study demonstrated that PSLD can achieve sufficient decompression with a resultant significant reduction in pain and disability without leading to serious complications throughout postoperative follow-up. Although operative time increased according to the increase in operative disc levels, hospital stay was very similar regardless of the PSLD level. In a recent review article comparing parameters between MED and open laminectomy for spinal stenosis, Wong et al. [
Spinal stenosis, defined as a narrowing of the vertebral canal and/or the foramen causing compression of lumbosacral nerve roots, is the most common lumbar spine problem in people >65 years old [
In our study, only a small part of the superior facet process encroaching upon the lateral recess was removed; hence, the PSLD-operated cases demonstrated minimal facet removal. Another bony removal consisted of a small hole in the unilateral lamina of the endoscope to gain access to the epidural space. Eventually, most of the facet joint could be preserved even after PSLD, and this is one advantage of PSLD. According to our results, endoscopic laminectomy and foraminotomy appear to be safe and effective alternatives for surgical treatment of lumbar spinal stenosis in adults [
Open microscopic laminectomy or laminectomy has become a standard surgical management of degenerative lumbar stenosis. However, damage to the posterior ligamentum, muscles, and tissues remains unavoidable [
A new endoscopic system, stenoscopy, was designed in a surgeon-friendly manner to be used to achieve a translaminar or interlaminar approach to an epidural space lesion in the spinal canal and to perform decompression and/or discectomy in a safe and convenient manner. At 12 month postoperative follow-up, all clinical parameters, including changes in VAS and ODI (
In our study, the overall complication rate was much lower than that for MED (2.9% versus 7.9%). Among the complications, durotomy occurred most frequently, but at a low rate of seven cases, (53.8% of 13 complication cases; 1.9% of 450 total cases). Based on our experience, the incidence of dural tears appeared to increase when the superior articular process of the ipsilateral and contralateral side was resected. Intraoperatively, a thin layer of Tacho-Sil, a hemostatic dura sealant, possibly might help repair the site of the dural tear and defects [
The reason for low overall complication rates might be that all five surgeons who performed the PSLDs had >10 years of clinical experience as a spine surgeon. There one case of infection might be an end result of quite a large amount of continuous saline irrigation (average 4,000 mL) throughout each PSLD procedure. Also, a small single skin entry might be the reason for our extremely low infection. No patient demonstrated a significant neurological deficit. PSLD is expected to be used in patients with foraminal stenosis and all types of herniated discs at all spine levels. It is hypothesized that endoscopic spine surgery, such as PSLD, will replace most of the open or microscopic spine surgical procedures in the near future.
Some limitations are associated with this study. First, this was a retrospective study, and it was difficult to control the bias and confounding variable. Second, there was no control group for comparison. Third, the follow-up was not long enough to conclude the surgical outcomes and complications. Because the initial benefits of surgical decompression might deteriorate with time [
Our study demonstrated that full endoscopic decompressing procedures using PSLD have therapeutic feasibility in the surgical treatment of lumbar stenosis. PSLD achieved postoperative improvement, which was confirmed by the clinical follow-up and measurement of the postoperatively enlarged area, with minimal removal of medial facet joints and minimal damage in paraspinal muscles as evident by MRI. Monoportal PSLD has a potential for managing monolevel and multilevel spinal stenoses. PSLD results appeared compatible with those of conventional surgical treatment. Accordingly, PSLD could be an alternative to microscopic decompression or MED in the surgical management of lumbar stenosis along with some potential advantages, such as shorter hospital stays, earlier return to the workplace, and lower infection rate. Prospective randomized clinical trials are strongly warranted.
No potential conflict of interest relevant to this article was reported.
(A, B) Preoperative and postoperative sagittal 6 mm cutting from upper to lower ligamentum flavum MRI. (C, D) Preoperative and postoperative cross-sectional area. ★ (black), decompressed segment; ☆ (white), a calculated segment with 6 mm height; U, upper cross-sectional segment; M, middle segment; L, lower segment.
(A–C) Computed tomography shows mean laminar sizes and facet angles in the lumbar stenosis patients. In this study, lamina size was <11 mm from L5 to L3, with a steady decrease in facet angle from L5 to L3.
(A, B) Percutaneous stenoscopic lumbar decompression set. The dimensions are 120 mm length, 8.4 mm outer diameter scope, 5.7 mm working channel, and a 12° field of view.
Two cases of percutaneous stenoscopic lumbar decompression. (A, C) Preoperative MRI. (B, D) Postoperative MRI shows the entry point of approach, fatty atrophy between the spinous process and multifidus muscle ((arrow, postoperative drain). MRI, magnetic resonance imaging.
Surgical technique. (A) Flavectomy with 5 mm Kerrison punch. (B) Bone work with 3 mm drill. (C) Axilla and shoulder of the exposed nerve root. (D) Nerve root retraction and annuloplasty. (E) Contralateral axilla and shoulder. (F) Endpoint of percutaneous stenoscopic lumbar decompression.
L3–4, L4–5, L5–S1, and 3-level decompression with one skin incision by the jumping technique. (A, B) Preoperative MRI. (C, D) Postoperative MRI shows enough decompression without paraspinal muscle damage. (E) The jumping technique for multiple layer decompression with one skin incision. (F) Postoperative drainage and endpoint of percutaneous stenoscopic lumbar decompression. MRI, magnetic resonance imaging.
L4–5 preoperative (A, B) and postoperative (C, D) magnetic resonance imaging. Full decompression with minimum bone work and no muscle injury are the advantages of percutaneous stenoscopic lumbar decompression (C, D).
L3–4, L4–5, L5–S1, and 3-level decompression with one skin incision. (A) Preoperative sagittal MRI. (B) Postoperative sagittal MRI. (C) Preoperative axial MRI. (D) Postoperative axial MRI. MRI, magnetic resonance imaging.
Demographic data of 450 patients (532 disc level) with degenerative lumbar stenosis
Characteristic | Value |
---|---|
Age (yr) | 67.1±12 |
Sex (male:female) | 254:196 |
Duration of symptoms (mo) | 22.3±21.4 |
Decompression level (n=450) | |
1 Level | 388 |
2 Level | 42 |
3 Level | 30 |
Decompression segment (n=532) | |
1 Level (n=388) | |
L1–2 | 10 |
L2–3 | 28 |
L3–4 | 52 |
L4–5 | 139 |
L5–S1 | 159 |
2 Level (n=84) | |
L1–2 | 4 |
L2–3 | 12 |
L3–4 | 20 |
L4–5 | 30 |
L5–S1 | 18 |
3 Level (n=60) | |
L1–2 | 3 |
L2–3 | 10 |
L3–4 | 20 |
L4–5 | 17 |
L5–S1 | 10 |
Values are presented as mean±standard deviation or number.
Lamina size and facet angle in patients with lumbar stenosis; specification of stenoscopy
Characteristic | Value |
---|---|
Lamina size (mm) (n=50) | |
L3 | 9.09±1.75 |
L4 | 10.32±3.37 |
L5 | 10.67±3.20 |
Facet angle (°) (n=50) | |
L3–4 | 15.05±2.31 |
L4–5 | 46.53±3.02 |
L5–S1 | 55.20±3.52 |
Specifications of stenoscopy | |
Outer diameter (mm) | 8.4 |
Working channel (mm) | 5.7 |
Optic view angle (°) | 12 |
Values are presented as mean±standard deviation or number.
Mean operation time and duration of hospitalization
Variable | Value |
---|---|
Operation time of bilateral decompression (min) | |
1 Level | 32.3±15.25 |
2 Level | 64.4±37.3 |
3 Level | 95.5±28.6 |
Duration of hospitalization (day) | |
1 Level | 1.42±0.1 |
2 Level | 1.47±2.7 |
3 Level | 1.49±5.2 |
Values are presented as mean±standard deviation.
Pre- and postoperative changes in cross-sectional area of lower, middle, and upper segment
Segment | Mean cross-sectional area of canal |
Mean increased cross-sectional area (%) | ||
---|---|---|---|---|
Preoperative | Postoperative | |||
Lower | 161.4±3.2 | 234.4±4.1 | <0.001 | 45.3 |
Middle | 121.3±3.2 | 206.9±3.6 | <0.001 | 71.1 |
Upper | 125.9±3.6 | 179.3±3.3 | <0.001 | 39.7 |
Values are presented as mean±standard deviation, unless otherwise stated.
Patients pain assessment before and after surgery
Clinical data | 1 Level | 2 Level | 3 Level |
---|---|---|---|
VAS back | |||
Preoperative | 6.00±4.21 | 6.20±2.74 | 6.52±4.02 |
Postoperative 1 wk | 2.70±4.14 | 4.50±0.72 | 4.60±0.62 |
Postoperative 3 mo | 1.92±0.79 | 2.51±1.32 | 2.67±5.58 |
Postoperative 12 mo | 2.13±3.01 | 2.24±4.02 | 2.27±1.62 |
VAS leg | |||
Preoperative | 7.10±2.51 | 7.20±5.03 | 7.50±5.22 |
Postoperative 1 wk | 2.31±7.21 | 2.43±6.41 | 2.47±2.73 |
Postoperative 3 mo | 2.82±0.71 | 2.86±3.91 | 2.91±2.61 |
Postoperative 12 mo | 2.31±4.15 | 2.40±0.79 | 2.41±1.92 |
Oswestry Disability Index | |||
Preoperative | 58.81±11.65 | 60.32±21.03 | 62.72±21.92 |
Postoperative 3 mo | 25.29±3.57 | 26.63±32.11 | 27.02±32.07 |
Postoperative 12 mo | 23.72±4.12 | 24.72±2.76 | 25.92±27.92 |
Values are presented as mean±standard deviation.
VAS, Visual Analog Scale.
postoperative complications
Complication | Value |
---|---|
Incidental dural tear (root herniation) | 7 (2) |
Wound infection | 1 |
Epidural hematoma | 5 |
Reoperation | |
Percutaneous stenoscopic lumbar decompression | 4 |
Open microscopic decompression | 2 |