Full-Endoscopic Posterior Lumbar Interbody Fusion with Epidural Anesthesia: Technical Note and Initial Clinical Experience with One-Year Follow-Up

Figures & data

Table 1 The Fusion Grade of Brantigan and Steffee Criteria

Grade	Fusion Result	Radiological Description
1	Obvious radiographic pseudarthrosis	Collapse of vertebral construct, disc height reduction, vertebral slippage, screws break, cage migration, or bone graft resorption.
2	Probable radiographic pseudarthrosis	Significant resorption of bone graft, or visible gap or lucency of the fusion area over 2mm.
3	Radiographic status uncertain	Visible bone graft in the fusion area with approximately the density originally achieved surgically; A small visible lucency or gap in the fusion area with at least half of the graft area showing no lucency between the graft bone and vertebral bone.
4	Probable radiographic fusion	Bone bridges formation in the entire fusion area with at least the density originally achieved surgically. No lucency between the donor bone and vertebral bone.
5	Radiographic fusion	Radiographical evidence showing more dense and mature bone in the fusion area. No interface between the donor bone and vertebral bone. Sclerotic line between the graft and vertebral bone. Mature bony trabeculae bridge in the fusion area, fusion of facet joints.

Figure 1 The schematic diagram of the procedure. (A) Placing work cannula targeting to the junction of spinous space and lamina; (B) Removing the inferior articular process; (C) Exposing and decompressing the nerve root; (D) Implanting allograft bone and PEEK cage.

Figure 2 Intraoperative endoscopic images. (A) Confirming and marking skin entry points by C-arm; (B) Placing work cannula targeting to the junction of spinous space and lamina under C- arm fluoroscopic control; (C) Removing the inferior articular process, partial lamina, and the partial superior articular process by endoscopic drill under the full visualization; (D) Exposing nerve root after removing ligamentum flavum and hypertrophied tissues; (E) Scrapping away adequately cartilaginous endplate; (F) Checking cage position by full endoscopic visualization.

Figure 3 Intraoperative C-arm fluoroscopic control. (A–C) Installing expandable tubular, dilating intervertebral space and implanting allograft bone and PEEK cage under the C-arm fluoroscopic control; (D) Lateral X-rays showing satisfactory cage position; (E and F) Anteroposterior and lateral X-rays showing correct implant position.

Figure 4 Instruments of ZELIF. (A and B) Guide wire, dilator, working tube and baffle of ZELIF^® system; (C) Reamers and scrapers.

Table 2 Baseline Clinical and Perioperative Characteristics of Patients

Characteristics		Value	Incidence (%)
N		24	–
Age (years)		59.54±7.37	–
Gender	Males	10	41.67%
	Females	14	58.33%
Weight (kg)		61.5±9.61	–
Operative segment	L3/L4	2	8.33%
	L4/L5	12	50.00%
	L5/S1	10	41.67%
Clinical diagnosis	Lumbar spondylolisthesis	6	25.00%
	Lumbar disc herniation with instability	8	33.33%
	Lumbar spinal stenosis	10	41.67%
Operation time (min)		209.17±39.49	–
Amount of bleeding (mL)		43.33±14.87	–
Hospitalization duration (d)		8.67±3.59	–
Follow-up time (m)		15.21±2.27	–
Fusion		24	100%
Postoperative complications	Wound infection	1(4.17%)	12.5%
	Paresthesia	2(8.33%)

Table 3 Preoperative and Follow-Up Functional Scores

Characteristics		Value	P
Lower back pain VAS	Preoperative	5.83±1.09	–
	Postoperative 3 days	3.54±0.72*	< 0.001
	Postoperative 3 months	2.42±0.65*	< 0.001
	Postoperative 6 months	1.71±0.75*	< 0.001
	Postoperative 12 months	0.96±0.69*	< 0.001
Lower extremity pain VAS	Preoperative	6.54±1.22	–
	Postoperative 3 days	4.33±0.92*	< 0.001
	Postoperative 3 months	2.58±0.83*	< 0.001
	Postoperative 6 months	1.42±0.78*	< 0.001
	Postoperative 12 months	0.71±0.62*	< 0.001
ODI scores%	Preoperative	42.04±3.96	–
	Postoperative 3 days	35.33±5.25*	< 0.001
	Postoperative 3 months	25.17±4.26*	< 0.001
	Postoperative 6 months	17.67±4.38*	< 0.001
	Postoperative 12 months	12.75±2.71*	< 0.001
SF-36 PCS	Preoperative	34.96±4.63	–
	Postoperative 3 days	39.88±4.92*	< 0.001
	Postoperative 3 months	43.79±4.84*	< 0.001
	Postoperative 6 months	47.25±4.57*	< 0.001
	Postoperative 12 months	52.08±6.05*	< 0.001
SF-36 MCS	Preoperative	39.38±5.70	–
	Postoperative 3 days	42.29±5.77*	< 0.001
	Postoperative 3 months	45.21±6.21*	< 0.001
	Postoperative 6 months	48.92±5.48*	< 0.001
	Postoperative 12 months	53.13±5.97*	< 0.001
Fusion grade	Grade 4	4	16.67%
	Grade 5	20	83.33%

Notes: *P < 0.001, postoperative 3 days, 3 months, 6 months and 12 months compared with preoperative. Grade 4, probable fusion. Grade 5, fusion.

Abbreviations: VAS, visual analog scale, ODI, Oswestry disability index, PCS, physical component score, MCS, mental component score.

Figure 5 Images were obtained from a 48-year-old male patient with the degenerative spondylolisthesis at L5-S1. (A and B) Sagittal and axial CT images showing degenerative spondylolisthesis at L5-S1; (C and D) Postoperative anteroposterior and lateral X-rays images showing correct cage and pedicle screws after full Endo-PLIF; (E–H) Postoperative sagittal CT images at 3, 6, 9, 12 months showing interbody fusion.

Figure 6 Images were obtained from a 51-year-old female patient with the lumbar spinal stenosis at L4-5. (A–D) Preoperative X-rays and MRI images showing lumbar spinal stenosis at L4-5; (E and F) Postoperative sagittal and axial MRI images showing complete decompression after full Endo-PLIF; (G and H) Postoperative anteroposterior and lateral X-rays at 3 months showing correct position; (I and J) Postoperative sagittal and axial CT images at 6 months showing interbody fusion.