The purpose of this study is to evaluate the clinical outcome of cauda equina syndrome (CES) using percutaneous endoscopic lumbar discectomy (PELD) and open lumbar microdiscectomy (OLM).
Fifteen patients with CES either underwent PELD or OLM from January 2017 to December 2019. The patients were divided into 2 groups according to the surgical methods: the PELD group (with 7 patients, 5 males and 2 females) and the OLM group (with 8 patients, 6 males and 2 females). The clinical outcomes were evaluated by the Visual Analogue Scale score (VAS), motor grade of lower extremities, perineal sensation, anal tone, and bladder dysfunction.
Both groups reported a significant postoperative reduction of VAS score for back and leg pain. When comparing the two groups, there was no significant difference in the improvement of leg pain. However, the improvement in back pain was significantly higher in the PELD group than in the OLM group (p=0.05). In the PELD and OLM groups, all 15 patients showed an improvement in preoperative CES symptoms including impaired lower limb motor power, perineal sensations, anal sphincter tone and bladder function at the one-year follow-up. The operation time (p=0.01) and length of hospital stay (p=0.01) were shorter in the PELD group compared with the OLM group. In the PELD group, the intraoperative bleeding was negligible whereas in the OLM group.
The advantages of PELD, indicate it is a good alterative or option for the treatment of CES patients considering the appropriate indication.
Cauda equina syndrome (CES), which is mainly caused by severe compression of the nerve roots below the conus medullaris, is one of the most serious and complicated spinal pathologies. It is a relatively rare condition most commonly caused by extreme lumbar disc herniation (LDH) and accounts for about 1% to 3% of LDH patients [
Traditionally, open lumbar microdiscectomy (OLM) has been widely considered as a standard procedure for CES [
With the instrumental development of endoscopes and in an attempt to reduce the complication rate, percutaneous endoscopic lumbar discectomy (PELD) has become increasingly popular over the past years. Many studies have shown comparable clinical outcomes of PELD compared with OLM [
On the basis of these advantages, several studies have reported favorable outcomes of CES treated by PELD [
We performed a retrospective cohort study approved by the Institutional Review Board of Daegu Wooridul Spine Hospital (IRB No. 2022-01-WSH-001), and all participants gave informed consent before enrollment. Between January 2017 and Fifteen patients with CES underwent PELD or OLM.December 2019, a total of 15 consecutive patients with CES caused by lumbar central huge disc rupture were treated in Daegu Wooridul Spine Hospital by 4 neurosurgeons. Each surgeon had performed over 300 cases of PELD and over 1,000 cases of OLM throughout their career.
Inclusion criteria were a single level central huge LDH with the following so-called “red flag” symptoms: (1) unilateral or bilateral motor weakness, (2) absent or decreased perineal sensation, (3) absent or decreased or anal sphincter tone, or (4) bladder dysfunction. Exclusion criteria were as follows: (1) LDH concomitant with spinal stenosis, (2) disc herniation with calcified disc, (3) instability, (4) epidural abscess, or (5) neoplasms.
All cases were treated by PELD (with 7 patients, 5 males and 2 females) or OLM (with 8 patients, 6 males and 2 females) within a day of diagnosis of CES and postoperative magnetic resonance imaging was obtained right after the patients were allowed to stand and walk independently.
Medical chart and image databases were analyzed. Patient demographics including age, sex, affected level, body mass index (kg/m2), duration of symptoms before treatment, and neurological symptoms of CES were reviewed.
A standard transforaminal PELD procedure was performed using the inside-out technique. The procedure was performed under local anesthesia with the patient in the prone position on a radiolucent table and receiving supplemental nasal oxygen. An imaginary line was drawn to the annular puncture site and the skin entry site was marked for the planned surgical trajectory. After infiltration of the entry point (10–12 cm from the midline) with local anesthetics, an 18-gauge spinal needle was introduced into Kambin’s triangle under the fluoroscopic guidance with continuous patient feedback. The final target point of the spinal needle was the medial pedicular line on the anteroposterior view and posterior vertebral line on the lateral view. After inserting the needle in to the disc, discography using indigo carmine was performed to distinguish the pathological fragment clearly during the procedure. After insertion of a guide wire through the spinal needle, the spinal needle was removed and a small skin incision at the entry point was made. A tapered cannulated obturator was inserted along the guide wire and after contacting the annulus, the obturator was inserted into the disc space with hammering until its tip reached the midline on the anteroposterior view. A beveled working cannula was inserted into the disc space along the obturator under fluoroscopic guidance. After removing the obturator, an endoscope (TESSYS System; Joimax, Karlsruhe, Germany) was inserted through the working cannula and positioned at the annular defect site. This was confirmed using axial magnetic resonance imaging preoperatively. A targeted fragmentectomy was performed and constant saline irrigation was administered throughout the whole procedure. To remove the trapped disc fragment, the annular defect site was widened using a side-firing holmium: YAG laser (Lumenis Inc., Yokneam, Israel). In cases where the disc fragment was too large to pass through the cannula, it was vaporized by a laser or bipolar radiofrequency coagulator (Ellman International, Hicksville, NY, USA) to reduce the volume and removed with forceps. After removal of the disc fragment and decompression, the beating of the traversing nerve root and dural sac with the pulse of the artery was confirmed. The endpoints of neural decompression were complete visualization of the dural sac and traversing root, dural pulsation, irrigation flutter, and cough impulse. After confirming the relief of preoperative symptoms by asking the patients, the endoscope was withdrawn, and a sterile dressing was applied with a one-point suture (
The patient was placed in a kneeling prone position under general anesthesia. After confirming the target level using fluoroscopy, a 3 cm midline longitudinal skin incision was made, and the paravertebral muscles were dissected and retracted laterally. A Caspar lumbar retractor was applied to obtain a direct view of the operating field and the operative level was confirmed by fluoroscopy. OLM was performed following a bilateral approach. Under microscopic visualization, partial hemilaminectomy, medial facetectomy, and foraminotomy using a high-speed drill were performed. After removal of the ligamentum flavum, the same procedure was performed on the opposite side. The nerve root and thecal sac were retracted gently and the herniated disc fragment was removed with pituitary forceps. Following discectomy, the thecal sac and root were pulsated and retracted without resistance, confirming adequate neural decompression. After meticulous bleeding control, the muscle, subcutaneous tissue and skin were sutured in layer (
All statistical analyses were performed using SPSS Version 25 (IBM Corporation, Armonk, NY, USA). Quantitative data were expressed as the mean±SD (standard deviation) or frequency. Each category and difference between two groups were compared using appropriate statistical tools such as the Pearson correlation, Fisher’s exact test, the chi-square test, or the Mann-Whitney U-test. A p-value of <0.05 was considered statistically significant.
A total of 15 consecutive hospitalized patients with CES caused by lumbar central huge disc rupture were treated Daegu Wooridul Spine Hospital. Of the 15 patients, 7 underwent PELD and the remaining 8 underwent OLM. On postoperative magnetic resonance imaging, the disc fragment was removed completely in all cases. All patients were followed-up over a year after the procedure in an outpatient clinic and their clinical outcomes were recorded in detail on a medical chart. One patient in each group had a telephone survey because they refused to visit the hospital.
The patients’ demographic and clinical characteristics are summarized in
The perioperative outcomes of PELD and OLM for CES are summarized in
In the PELD and OLM groups, all 15 patients showed an improvement in preoperative CES symptoms including impaired lower limb motor power, perineal sensations, anal sphincter tone and bladder function at the one-year follow-up.
The operation time (45.00±4.08 vs. 96.25±10.60, p=0.01) and length of hospital stay (2.43±0.53 vs. 10.63±2.26, p=0.01) were shorter in the PELD group compared with the OLM group. In the PELD group, the intraoperative bleeding was negligible whereas in the OLM group, the estimated bleeding was 235±105 mL.
No patients suffered from disc recurrence, postoperative infection, or segmental instability requiring fusion surgery during postoperative follow-up.
CES is a very rare condition. That accounts for 1% to 3% of all lumbar disc herniations [
CES can seriously impair the quality of life without adequate treatment. Busse et al. [
Lam et al. [
The aim of our study was to examine differences in clinical outcomes between PELD and OLM. The result of our study showed that there were no significant differences between the two procedures.
PELD has several disadvantages regarding its limited field of view including difficult bleeding control, and because of the working channel, limited instruments can be used during the procedure.
Especially, increased intradiscal pressure resulting from insertion in the working channel, results in nerve root compression. However, in the case of degenerative disc disease, several studies have reported that the intradiscal pressure was low.
Sato et al. [
Schnake et al. [
In contrast, performing OLM requires the retraction of the nerve root. In the case of CES, nerve root retraction result in worse neurologic outcomes.
Several studies have reported the advantages of PELD, and our study confirmed these advantages including less soft tissue trauma, better bony preservation, rapid recovery, and avoiding root retraction.
On the basis of these advantages, several studies have demonstrated the better outcomes of CES treated by PELD [
Chen et al. [
Krishnan et al. [
Li et al. [
Limitation of the study is the retrospective study design and small cohort population. In addition it was not possible to quantitatively evaluate the anal sphincter tone or bladder dysfunction
In conclusion, there were no significant differences between PELD and OLM in clinical outcomes for CES. The advantages of PELD (the procedure can be performed under local anesthesia, less soft tissue trauma, better bony preservation, rapid recovery, and avoiding root retraction), indicate it is a good alternative or option for the treatment of CES patients considering the appropriate indication.
A retrospective cohort study approved by the Institutional Review Board of Daegu Wooridul Spine Hospital, and all participants gave informed consent before enrollment (2022-01-WSH-001).
No potential conflict of interest relevant to this article.
A 37-year-old female patient underwent PELD for disc herniations at the L3-4 level. Preoperative T2 weighted sagittal and axial MRI images (A, B) and intraoperative c-arm images (C, D) demonstrating a huge herniation at the L3-4 level. Postoperative T2 weighted sagittal and axial MRI images (E, F) showed that the herniated disc completely removed.
A 45-year-old male patient underwent bilateral OLM for disc herniations at the L4-5 level. Preoperative T2 weighted sagittal and axial MRI images (A, B) demonstrating a up-migrated huge disc at the L4-5 level. Postoperative T2 weighted sagittal and axial MRI images (C, D) showed that the herniated disc completely removed.
Perioperative VAS score for PELD and OLM.
(A) Improved VAS score for leg pain in PELD and OLM. (B) Improved VAS score for back pain in PELD and OLM.
Preoperative data of PELD and OLM groups
PELD | OLM | p-value | |
---|---|---|---|
Number of patients | 7 | 8 | - |
Age (yr) | 34.57±8.848 | 41.87±15.761 | 0.524 |
Gender (M/F) | 5/2 | 6/2 | 0.876 |
Level | 0.189 | ||
L2-3 | 1 | 0 | |
L3-4 | 2 | 0 | |
L4-5 | 4 | 7 | |
L5-S1 | 0 | 1 | |
BMI (kg/m2) | 27.94±4.013 | 27.09±6.210 | 0.487 |
Symptom duration (d) | 15.29±11.041 | 17.88±10.816 | 0.767 |
Symptom | |||
Motor weakness | 5 | 6 | 0.876 |
Perineal sensation (abscent/decreased) | 0/7 | 0/8 | - |
Anal tone (abscent/decreased) | 0/7 | 1/7 | 0.333 |
Bladder dysfunction | 6 | 6 | 0.605 |
Perioperative outcomes of PELD and OLM for cauda equina syndrome caused by lumbar disc herniation
PELD | OLM | p-value | |
---|---|---|---|
Pre-op VAS | |||
Back | 9.00±0.816 | 8.50±0.535 | 0.206 |
Leg | 8.86±0.690 | 9.00±0.926 | 0.758 |
Post-op VAS | |||
Back | 2.57±0.535 | 4.13±0.641 | 0.002 |
Leg | 2.29±0.488 | 2.88±0.835 | 0.140 |
Improvement of VAS | |||
Back | 6.42±1.134 | 4.38±0.916 | 0.005 |
Leg | 6.57±0.787 | 6.13±0.641 | 0.291 |
Operation time (min) | 45.00±4.082 | 96.25±10.607 | 0.001 |
Intraoperative bleeding | Negligible | 235.63±105.575 | - |
Hospital Stay (d) | 2.43±0.535 | 10.63±2.264 | 0.001 |