Transforaminal percutaneous endoscopic discectomy for symptomatic gas-filled discal cysts-report of three cases and literature review

Radiographic characteristics-based classification system for percutaneous endoscopic lumbar discectomy surgical approach selection in patients with L5-S1 disc herniation: a hierarchical clustering analysis

Background

No classification system exists for aiding the selection of surgical approaches in L5-S1 disc herniation when undergoing percutaneous endoscopic lumbar discectomy (PELD). We aimed to identify radiographic subtypes to aid the selection of percutaneous endoscopic transforaminal discectomy (PETD) and percutaneous endoscopic interlaminar discectomy (PEID) in patients with L5-S1 disc herniation via unsupervised hierarchical clustering analysis.

Methods

In this retrospective case-control study, we gathered 296 anteroposterior and lateral lumbar spine radiographs (dataset 1) from Tianjin Hospital between January 2016 and October 2021 for clustering analyses. Additionally, we analyzed 111 patients who underwent PEID or PETD for L5-S1 disc herniation at Tianjin Hospital from January 2016 to August 2022. We included patients with radicular leg pain or back pain associated with intra-canal disc herniation who failed in conservative treatments over 6 weeks. First, pair-wise Spearman correlation coefficients were calculated among plain radiographic metrics in dataset 1 to reveal the association among these radiographic metrics. Second, hierarchical clustering analysis was conducted to unsupervised cluster the plain films into several subtypes. Last, for each radiographic subtype, the intraoperative blood loss (IBL), operation time (OT), total operating room time (TORT) along with visual analogue scale (VAS) and Oswestry Disability Index (ODI) were compared between patients underwent PETD or PEID with age as covariates.

Results

This study yielded 3 main findings: (I) iliac height (IH) was negatively correlated with intervertebral foramen width (IFW), intervertebral foramen height (IFH), and intertransverse height (ITH) (R=-0.50, -0.42, and -0.46, all P<0.001), ITH was positively correlated with IFW and IFH (R=0.40 and 0.53, all P<0.001); (II) 2 lumbosacral radiographic subtypes were identified via hierarchical clustering analysis; (III) relative to subtype 1, the patients identified as subtype 2 exhibited lesser IBL, shorter OT, and shorter TORT following PETD (t=2.92, P=0.006; t=2.65, P=0.012; t=3.17, P=0.003).

Conclusions

The morphology pattern of the lumbosacral region affect the ease of different PELD procedures when performing percutaneous discectomy at the segment of L5-S1. Without considering the type of disc herniation, this classification system might aid spine surgeons in the selection of an appropriate surgical approach.

A rare gas-containing lumbar synovial cyst treated by percutaneous transforaminal endoscopic cystectomy: A case report and literature review

Spinal synovial cysts are rare entities for which standard surgical strategies are inconsistent. Here, we present an uncommon intraspinal gas-containing synovial cyst treated by percutaneous transforaminal endoscopic cystectomy. A 52-year-old man presented with radicular pain and intermittent claudication that had persisted for one month. Computed tomography revealed an intraspinal cystic lesion anteromedial to the left L4-L5 articular joint and the center of the lesion manifested gas contents. A transforaminal endoscopic procedure was performed and confirmed as a safe and minimally invasive technique for gas-containing lumbar synovial cysts. It provides a valuable substitution and supplementation to open surgery.

A postoperative complication of lumbar discectomy: A discal/annular cyst

Background

A postoperative discal/annular cyst following lumbar discectomy may reproduce the symptoms/signs of a recurrent lumbar disc herniation (i.e., back pain and radiculopathy).

Case Description

A 21-year-old rugby player developed leg pain after an uncomplicated lumbar microdiscectomy. The repeat lumbar magnetic resonance imaging confirmed a postoperative lumbar annular/ discal cyst, for which he underwent repeat surgery. The diagnosis was further confirmed histopathologically at surgery.

Conclusion

Although rare, postoperative discal/annular cysts may be potential causes of recurrent postoperative pain and lumbar radiculopathy mimicking recurrent disc herniations.

Could gas-filled pseudocyst mimick extruded disc herniation?

There are case reports and small case series in the literature reporting gas-filled pseudocysts (GFP). However, a systematic review presenting overall view of the disease and its management is still lacking. In the present study, we aimed to make a systematic review of GFP cases, and present an exemplary case of ours. Our second aim was to discuss current theories for pathogenesis of GFP. A systematic review of GFP was conducted using Preferred Reporting Items for Systematic Reviews and Meta-Analyses guideline. Two large-scaled data search engines were used. A total of 53 articles were retrieved from the literature and presented with an exemplary case of ours. Mean age of the historical cohort was 59.47 years. There were 66 male (54.1%) and 56 female (45.9%) patients. The most prevalent clinical presentation was radicular sign/symptom in lower limbs with (29.1%) or without low back pain (LBP) (67%). Gas-filled pseudocyst has most commonly been diagnosed at the lower lumbar spine (L4-L5, 45.3%; L5-S1, 37.7%). Surgery was the treatment of choice in most of the patients (80%). In the whole cohort, 79.1% of the patients had complete recovery. Gas-filled pseudocysts are rarely observed in daily practice. They present mostly in men at the age of 60s. Precise differential diagnosis determination using appropriate imaging would help clinicians treat the patients properly. Gas-filled pseudocysts should be treated similarly to other spinal pathologies causing nerve root compression.