Calcified lumbar disc herniation (CLDH), with a low incidence rate, is a special type of lumbar disc herniation (LDH). Calcified disc herniation, with hard structure, usually adheres extensively to surrounding tissues such as nerve roots and the dural sac. Most patients with CLDH have severe low back and leg pain symptoms and even severe neurological symptoms in the acute stage[[i]].However, conservative treatments fail to effectively relieve symptoms.
Patients with CLDH are typically treated by traditional open surgery. Traditional open surgery completely resects the calcified intervertebral disc with good clinical outcomes. However, traditional open surgery, with a long incision, extensive stripping of the paravertebral muscles and laminectomy, has some deficiencies, such as significant tissue damage, considerable intraoperative blood loss, muscle denervation and atrophy, and even spinal instability[2, 3].
Percutaneous endoscopic lumbar discectomy (PELD), including percutaneous endoscopic interlaminar discectomy (PEID) and percutaneous endoscopic transforaminal discectomy (PETD), is a minimally invasive operation for the treatment of LDH. Some studies demonstrated that PELD had similar clinical results as traditional open discectomy[4, 5]. PELD has less intraoperative blood loss, less trauma, faster postoperative recovery, and shorter hospital stay than traditional open surgery. However, it is difficult and challenging to treat CLDH with PELD because the calcified disc tightly adheres to nerve roots and the dural sac. In recent years, with the appearance of surgical instruments such as ultrasonic osteotomes and endoscopic grinding drills, PELD has been gradually applied to the treatment of CLDH. However, there are no studies and reports comparing the efficacy of PEID and PETD in the treatment of L5-S1 CLDH. The research aims to compare the clinical effect of the two surgical approaches and to provide clinical guidance for L5-S1 CLDH.
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Fig.1 Schematic diagrams of PEID and PETD (A-B). A The schematic diagram of PEID. B The schematic diagram of PETD.
Fig.2 Endoscopic images of PEID (A-D) and PETD (E-H). A The ligamentum flavum was cut by scissors. B The calcified and herniated disc tissue was cut by an ultrasonic osteotome. C The calcified and herniated disc were taken out by a nucleus pulposus forceps. D The nerve root and dural sac were fully decompression. E An ultrasonic osteotome was used to cut the calcified disc. F A nucleus pulposus forceps was used to remove the calcified and herniated disc. G The nerve roots and dural sac were moved. H A bipolar radiofrequency was used to hemostasis.
Fig.3 Pre- and post-operative MRI and CT (A-H). A-D Preoperative CT and MRI revealed lumbar disc herniation combined with calcification. E-H Postoperative CT and MRI showed that the calcified intervertebral disc was removed and the compressed nerve root had been relieved by PEID.
Fig.4 Pre- and post-operative MRI and CT (A-H). A-D Preoperative CT and MRI showed lumbar disc herniation combined with calcification. E-H Postoperative CT and MRI revealed the loosened nerve root after the calcified disc was removed by PETD.
Table 1 Demographic characteristics of both the PEID group and PETD group
Table 2 Surgical outcomes of both the PEID group and PETD group
Table 3 VAS and ODI scores of both the PEID group and PETD group