Endoscopic Management of Lumbar Disc Prolapse

Background: Endoscopic management of lumbar disc herniation as a minimally invasive procedure become more popular around the world. Although accepted surgical outcomes of the endoscopic approach to manage lumbar disc herniation [LDH], this procedure still to be relatively challenging and needs a high learning curve, so operative failures and complications may occur. The Aim of The Work: To assess using the endoscope in the management of lumbar disc prolapse by interlaminar approach using Easy Go and Destandau systems. Patients and Methods: This is study included twenty patients, who had lumbar disc herniation, and operated by using Easy Go and Destandau's endoscopic systems after the failure of conservative treatment. They were included between March 2016 and April 2020. They followed up for at least three months postoperatively. All were selected from the Neurosurgery Department, Al-Azhar University Hospitals, Egypt. Results: Low back pain was the main complaint reported by all patients. The radicular side was mainly the left side [70.0%] and L4/L5 was the most common affected level [65.0%]; the disc protrusion was mainly paracentral [80.0%]. There was a significant pain reduction after surgery when compared to before surgery. The outcome was excellent for 55.0%, good for 25%, fair for 15% and poor for 5%. Complications were in the form of unintended durotomy among 10.0%, nerve injury among 10.0% and infection among 5.0%. Conclusion: Endoscopic lumbar discectomy through interlaminar approach by Destandau's and Easy Go systems become a golden procedure to manage lumbar disc prolapse at any level especially L5-S1 as a minimally invasive technique with some accepted complications that can easily be managed compared to classic traditional open techniques.


INTRODUCTION
Currently, the treatment modalities for lumbar disc herniation [LDH] comprise conventional discectomy [CD] and percutaneous endoscopic lumbar discectomy [PELD]. Because of its high success rate of approximately 90% and good result, CD is considered the standard surgical method in the management of LDH unresponsive to conservative therapy. However, CD is associated with complications, including epidural scarring, destabilization of spinal canal structures, and tissue traumatization [1] . The technical advancement in endoscopes and instruments have led to the development of multiple approaches including the transforaminal, the extra foraminal and the interlaminar approach. The interlaminar approach is used in lumbar spinal stenosis and disc herniation mainly located inside the spinal canal, which is technically difficult to manage through the transforaminal technique, and especially at L5-S1 due to the large transverse processes, facets, the narrow disk space and the iliac crest [2][3] . Ruetten et al. performed for the first time the full-endoscopic discectomy by transforaminal [4] and interlaminar [5] approaches. After that, the fullendoscopic discectomy has become the most common, and minimally invasive approach for the management of lumbar disc herniation [LDH].
Due to the high rate of success, cost-effectiveness, and minimally invasive nature, fully endoscopic interlaminar discectomy [FILD] become more familiar for both surgeons and their patients for management of LDH. This technique for treating LDH specially L5-S1, has obtained popular validation, and also produced satisfied effects of lumbar spinal stenosis [6] . Spine surgeons are accustomed to interlaminar [IL]-PELD as the anatomic orientations are similar to open surgery, although there is a learning curve. The systems for endoscopic interlaminar approach are either a conic "freehand" working channel [the Endospine by J. Destandeau] or a tubular retractor, introduced by Foley and Smith. Irrespective of the remarkable development of endoscopic procedures and instrumentation leading to good results comparable to open surgery, surgeons still have some challenges in PELD [7][8][9] .

AIM OF THE WORK
The current study aimed to assess the usage of the endoscope in the management of lumbar disc herniation through the interlaminar approach using Easy Go and Destandau systems.

PATIENTS AND METHODS
This study, included twenty patients have lumbar disc herniation operated by using Easy Go and Destandau's endoscopic systems after the failure of conservative treatment between March 2016 and April 2020 at the Neurosurgery Department, Al-Azhar University Hospitals. All patients have lumbar disc herniation with the following criteria: Unilateral sciatica, no response to nonsurgical management for at least 1.5-month, one level of lumbar disc herniation. The following patients were excluded from this study: Cases proved to have bilateral sciatica, multiple lumbar disc herniation, and ossified disc, any degree of spinal instability, recurrent lumbar disc herniation or lumbar canal stenosis. All patients in this study were subjected to the following: Clinical assessment [history and examination, radiological assessment by MRI lumbosacral spine and plain X-ray lumbosacral spine [A-P and lateral views], operated by Easy Go and Destandau's endoscopic spine systems. Duration of post-operative stay, postoperative clinical outcome and sequel were recorded. Follow-up for at least three months postoperative and clinical outcomes were assessed by using Visual Analogue Scale [VAS] [for Mean pre-and post-operative pain score measurement]. Patients Satisfaction was measured by Modified Macnab Criteria at three months postoperatively.

Ethical considerations:
The study protocol was revised and approved by the local research and ethics committee of Al-Azhar Faculty of Medicine. In addition, each patient signed an informed consent after full explanation of study protocol. The study completed in line with research ethics code of Helsinki Declaration. The data are available on request.
Recorded data were coded and fed to the statistical package for social sciences software, to be analyzed, we used version 20.0 [SPSS Inc., Chicago, Illinois, USA]. Frequency and percentages were used to report qualitative data, while mean ± standard deviation [SD] were used to represent quantitative variables. A one-way analysis of variance [ANOVA] used to compare multiple means. Paired sample t-test was used to compare different points of times of the same variable. Chi-square [x 2 ] was used to test association between categorical parameters. The p-value was considered significant if < 0.05.

RESULTS
This study includes 20 patients with age ranged 25

DISCUSSION
Open surgery still the ideal technique for treating lumbar disc herniation. However, the disadvantages of this surgery are the massive retraction and dissection of back muscles, more operative consumption of time, larger scars and bone removal [10] . The current study aimed to assess the results of endoscopic management of lumbar disc herniation. Overall, the results were excellent for 55.0%, good for 25%, fair for 15% and poor for 5%; with a statistically significant pain reduction after surgery, and pain reduction continued until the end of the third month after surgery. The complications were in the form of unintended durotomy among 10.0%, nerve injury among 10.0% and infection among 5.0%. There was mild intraoperative blood loss with a reasonable time of postoperative hospital stay duration. These data reflected the efficacy and relative safety of the procedure. Choi et al. [11] reported that, for full endoscopic inter-laminar discectomy, the complications rate was 18.5% [compared to 25.0% in the current one]. Epstein [12] reported that, surgeries under the direct vision could better distinguish between the nerve root and other tissues. However, nerve root injury remains one of the common complications of full endoscopic lumbar discectomy. In our study we have two cases 10% of unintended accidental nerve injury, one of them was just transient impairment of nerve function and cause partial foot drop that improved by physiotherapy and this patient return to work and daily activities after three months; the other patient was complete nerve injury with foot drop that not improved after two years of follow-up.
In studies reported by Zhou et al. [13] , nerve root injury occurred in 1.2% of cases. Choi et al. [14] noted that the working sheath could crush the exiting nerve root during the operation, and thus a prolonged operative time could lead to nerve irritation. Furthermore, motor weakness and temporary dysesthesia was reported as common complications in percutaneous endoscopic interlaminar discectomy [PELD]. The complications incidence was 2.00-6.53% according to previous study of Lee et al. [15] . Other common complications that have been reported in the literature include dural injuries, which are very serious complication of FILD [16][17] . Patients with small tears may be asymptomatic and may only need bed rest with a pressure dressing. However, patients with larger tearing, which can cause sciatica, uncontrolled CSF leakage, and development of a nerve root herniation, will always require secondary open repair surgery [18] .
In the current research, we have two cases [10 %] of unintended dural injury, one of them was just arachnoid bleb without CSF leakage intra-operative or post-operative, the other case was open dural injury that needed open repair at the same session. Ahn et al. [18] reported nine patients [1.1%] experienced symptomatic dural tears. In the series reported by Lee et al. [19] and Xia et al. [20] reported that, there was no intraoperative incidental durotomy or leakage of cerebrospinal fluid [CSF] after surgery. In series reported by Zhou et al. [13] , dural tears occurred in 0.9%. In series reported by Chen et al. [21] , dural tears and CSF leakage were detected in three patients due to adhesions between the calcification of disc and nerve root. However, their symptoms improved, and discharged after just one week of bed rest. Recurrent lumbar disc herniation [RLDHs] reported after different surgeries for lumbar discectomy. Phillips [22] defined RLDH as "disc herniation at the same level with a pain-free interval longer than six months after surgery regardless of whether the herniation is ipsilateral or contralateral". The risk factors include smoking, gender, obesity, and diabetes [23] . In this study we have a single case [5%] of recurrent lumbar disc prolapse after six months that operated again by open technique. Kaushal and Sen [24] have reported RLDH rate of 5.5, 5.7, and 3%. In addition, Joswig et al. [25] reported recurrent lumbar disc herniation occurred in 28%. Recurrence rates after discectomy vary between 5 and 20% being independent from the technique employed. Patient satisfaction was evaluated by "Modified Macnab Criteria [MMC] after three months of the operation and was excellent in 55%, good in 25%, fair in 15% and poor in 5%. In series reported by Oertel et al. [26] , patients went back to work within 1.5 month postoperatively with a range of one up to 20 weeks. Of the patients who evaluated by MMC, 83% [45/54] considered their postoperative status as excellent, 13% as good [7/54], 4% were not satisfied [2/54].
In this study, the infection occurred in one case [5%] and the patient had multiple risk factors and cured by antibiotics with medical improvement. In series reported by Cao et al. [27] , no patient with infections after PELD. In series reported by Zhou et al. [13] , there were no instances of posterior surgical site infection.
In the current trial, there was a significant decrease of pain in immediate and after three months of follow up when compared to values before surgery and no medication after three months in 16 patients [80%], 2 cases [10 %] with interrupted medication for occasional radicular pain and another case [5%] needed local steroid injection and another patient [5%] with RLDH that operated again after six months. In the series reported by Oertel et al. [26] , a significant radicular pain reduction permits the normal continuation of the patient's daily activities. No pain medication was reported in 89%. However, 6% reported recurrent pain without evidence for recurrent disc herniation or re-stenosis. Another 5% had a recurrent disc herniation during the follow-up period and were subsequently submitted to second surgical intervention.
Despite the significant advancement of endoscopic methods and instruments leading to successful outcomes comparable to open surgery, surgeons still have some difficulty in PELD. Most are about the inadequate elimination of a disc fragment, a learning curve, recurrence rate and radiation exposure. The risk of failure may be a major obstacle to perform PELD. In addition, PELD procedure and experience can affect the success of the technique. During the phase of steep learning curve, longer operative times are needed and the incidence of complications may be higher than those reported for more expert surgeons [14] .
One of the driving forces behind the minimal invasive spine surgery is economics, shorter hospital stay, reduced postoperative morbidity, and quicker recovery times. Depth perception in these techniques comes from experience rather than observation. Hence, surgeons keen to learn these techniques must combine these procedures during the early phase of learning with standard procedures in clinical practice [24] .
In conclusion, the current study revealed the effectiveness of endoscopic management of lumbar disc herniation. In addition, it is a relatively safe procedure with low complications rate. Thus, we recommend this technique to replace the traditional open surgery, unless there is absolute contraindication.

Financial and Non-financial Relationships and Activities of Interest
None