Lumbar spinal stenosis is common lumbar degenerative diseases with narrowing of the spinal canal leads to radicular leg pain, back pain, and neurological intermittent claudication. Generally, the first treatment for symptomatic lumbar stenosis is conservative management including medication, physical therapy, and nerve-block procedures [1-4]. Hypertrophy of the articular process and yellow ligament and disc herniation are the main reasons for worsening of the clinical symptoms of lumbar stenosis. Nerve compression induced by these degenerative changes manifests as low back pain and radiculopathic leg pain, which worsens when standing or walking, and commonly referred to as neurogenic intermittent claudication [5,6]. Lumbar spinal stenosis can be classified into 3 different types, central spinal canal stenosis, lateral recess stenosis, and foraminal stenosis, according to the anatomically neural compression area [7]. Many middle-aged and elderly patients with lumbar and low back pain do not achieve satisfactory results with conservative treatment alone, resulting in decreased activity level and quality of life, eventually requiring spinal surgery. Lumbar spinal stenosis is the main indication for spinal surgery in patients over 65 years of age [8]. A variety of surgical techniques, including tubular and microsurgical decompression and fusion surgery, have been used for the treatment of spinal stenosis that does not achieve satisfactory improvement with long-term conservative treatment. The development of endoscopic spinal surgery technology has made it possible to decompress the lumbar nerve using a full endoscope. In particular, in the case of elderly patients who are at high risk of general anesthesia, surgery is possible without general anesthesia, there is little tissue damage, the hospital stay is short, and the cost is low, but the surgical results are similar or better [9]. Full endoscopic surgery for lumbar nerve decompression is largely divided into an interlaminar approach and a transforaminal approach, and these approaches select the most suitable method according to the type of central stenosis, lateral recess stenosis, and foraminal stenosis stenosis. The interlaminar endoscopic technique is similar to microscopic and tubular decompression surgery, meaning the anatomic orientation is familiar and similar in both techniques. Full-endoscopic interlaminar decompression shows that all the procedures of open decompression can be completely substituted by endoscopic management.

Transforaminal endoscopic techniques have been reported to be successful in disc surgery and unilateral foraminal stenosis, but there are anatomic limitations for symptomatic bilateral recess stenosis. This technique is more useful in foraminal stenosis and lateral recess stenosis rather than central spinal stenosis These limitations, especially at the level of L5-S1, are a high iliac crest, a large L5 transverse process, a large facet joint, and a narrowed disc space [10,11]. With advances in endoscopic spinal surgery methods and instruments, earlier contraindications have become indications for full-endoscopic spinal decompression in the treatment of lumbar degenerative diseases.

There are some reports about complications and contraindications of full endoscopic lumbar decompression. Among them, Incidental durotomy is the most common complication [12-14].

Sairyo et al. [15] reported complications which included dural tear, postoperative hematoma, neural complication and inferior articular process fracture .

We used the Preferred Reporting Items for Systematic Review as a template for our systematic review. The review process started with a search of PubMed databases to identify articles on full endoscopic lumbar decompression. An independent reviewers assessed all articles and references and agreed on which articles should be included. To prevent selection bias during review, abstracts from the search were numbered and pasted into a document after deleting the publication journal, author, and institution. We used the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) guidelines as a template for our systematic review. These guidelines are an evidence-based minimum set of items aimed to help authors improve the reporting of systematic reviews and meta-analyses. The review process started with a search of PubMed and cochrane databases to identify articles on spinal stenosis and endoscopic decompression protocol. A reviewer assessed all articles and references and agreed on which articles should be included. To prevent selection bias during review, abstracts from the search were numbered and pasted into a document after deleting the publication journal, author, and institution. The initial search included keywords “spinal stenosis” and “endoscopic decompression” which returned 406 results.

Due to the high variation of relevant articles and anatomical locations, the search was modified to included “lumbar,” which produced 356 results after duplicate articles were identified and discarded. The search also included the exact surgical technique term “interlamiar” and returned 58 results published from 1980 to 2011. Exclusion criteria included no complication results reported (10 articles), microendoscopic surgery (10 articles), endoscopic interbody fusion (3 articles), spondylolisthesis (2 articles). Metastasis (1 articles), biportal surgery (7 articles) and studies not in English (1 articles). A total of 24 articles meeting our criteria were identified through the search process. Thus, 24 articles met the criteria and were analyzed (Figure 1).

Comprehensively, the contraindication of full endoscopic lumbar interlaminar decompression is Spondylolisthesis, Instability, previous surgery, foraminal stenosis, tumor, infection, scoliosis, main back pain, calcified disc herniation, medical problem, cauda equine syndrome, severe stenosis, trauma, and painless weakness were reported in the following order (Table 1).

Complications of full endoscopic interlaminar decompression were reported in the following order, dural tearing is the most common, epidural hematoma is the 2nd common, In addition to these two most common complications, various complications occur frequently in the following order. transient dysesthesia, urinary retention, motor weakness, cauda equine syndrome, wound infection, disc herniation, persistent pain, medical problem, Inferior articular process fracture, incomplete decompression, and instability (Table 2).

According to literature analysis, the interlaminar approach is effective for central spinal stenosis and lateral recess stenosis, whereas the transforaminal approach is preferred for foraminal stenosis and lateral recess stenosis. Contraindication in both methods has many things in common, but the interalminar approach is preferred in cases of multiple sites, bilateral symptoms, or high iliac crest. In the interlaminar approach, dural tearing and epidural hematoma are the most common, whereas in the transforaminal approach, dysesthesia and untreated pain are relatively common. Additionally, various complications such as transient dysesthesia, urinary retention, motor weakness, cauda equine syndrome, wound infection may occur.