Adjacent segment disease (ASDis) is a common sequela after lumbar spinal fusion. Current surgical treatment for ASDis with instability is decompression and extended fusion which could be done by posterior, lateral or anterior approach. Oblique lumbar interbody fusion (OLIF) could achieve indirect decompression of neural element. But OLIF has a limitation to directly decompress spinal canal in case of a concurrent herniated disc. Spinal endoscopy could enhance the visual field and facilitate herniated disc removal in case of ASDis with migrated lumbar disc herniation. Double trajectory of cortical bone trajectory (CBT) screw and pedicle screw in the same pedicle can be done to avoid the necessity to remove the previous instruments. Intra-operative computed tomography (CT) navigation can guide cortical bone screw when only narrow corridors are left due to the pedicle screws. This study will demonstrate a technical note for ASDis with a concurrent migrated disc herniation at L5-S1 level by combining endoscopic discectomy-assisted OLIF L5-S1 to direct and indirectly decompress neural element with intraoperative CT guided double trajectory CBT screw insertion in lateral decubitus position to avoid the necessity of previous instrument removal and decreased operative time.
The rate of spinal fusion for the treatment of lumbar degenerative diseases had been increasing over years [
Current surgical treatment for ASDis consisted of decompression and extended fusion which could be done by the posterior, lateral or anterior approach. Anterior lumbar interbody fusion (ALIF) or oblique lumbar interbody fusion (OLIF) could achieve indirect decompression without operating in the scarred area but may have the limitation in case of a concurrent herniated disc. Spinal endoscopy could enhance the visual field and facilitate herniated disc removal in case of ASDis with migrated lumbar disc herniation (LDH) [
This study will demonstrate a treatment strategy for ASDis at L5-S1 level by combining endoscopic discectomy-assisted OLIF with intraoperative CT guided CBT screw insertion in a lateral decubitus position.
A 67-year-old female patient presented with left foot drop and radiating pain to L5 dermatome of both legs for 1 month. In 2001, she had spinal stenosis which was successfully treated with laminectomy and instrumented fusion from L3 to L 5 level with pedicle screw and posterior lumbar interbody cage. In 2014, she also had a lumbar disc herniation at L2-L3 level and successfully treated with microdiscectomy. She had developed the radiating pain to L5 dermatome of both legs and gradual left foot drop for 1 month. She also had neurogenic claudication after walking for 20 meters. Her medical record showed well control hypertension and dyslipidemia. Her neurological examination revealed left knee extension grade III, left ankle dorsiflexion grade III, left great toe dorsiflexion grade I. Others key muscle motor power were grade V. Decreased pin prick and light touch sensation at L5 dermatome of both legs. Deep tendon reflexes were normal. Straight leg raising tests were negative at both legs. Anal tone and perianal sensation were intact. The pre-operative radiograph showed intact instrument from L3 to L5 level and degeneration of L2-L3 and L5-S1 level. The pre-operative magnetic resonance imaging (MRI) showed down migrated lumbar disc herniation at left L5-S1 level which causes left lateral recess stenosis (
After general anesthesia was administered, the patient was positioned to right lateral decubitus (
The skin was marked with fluoroscopic guidance (
For posterior fixation, the spine was approach by extension of distal part of the previous surgical scar with a subperiosteal approach to the lamina of L5 and S1 while the patient was still in the right lateral decubitus position. The sterile spheres and reference frame were attached to left iliac crest with sterile adhesive tape (
The patient’s back and leg pain improved. Post-operative period was uneventful. The post-operative radiograph showed improved sagittal balance and lordosis (
Prevalence of ASDeg after lumbar spinal surgery is 31-83% [
The type of operative treatment for ASDis is still controversy. Decompression alone has high re-operation rate up to 44% [
Some authors suggested using direct decompression in case of spinal stenosis with the concomitant herniated lumbar disc [
There were few studies about stand-alone OLIF for treatment of ASDis with instability [
Posterior fixation for ASDis could be done by explant of previous instruments or extension of the rods with domino connectors. Another option without needs to remove previous instruments is using double trajectory CBT screws for extension of fixation [
One of the disadvantages of anterior or lateral lumbar interbody fusion is time-consuming for repositioning the patient from lateral decubitus to prone position for percutaneous screw insertion. This disadvantage can be alleviated by screws insertion on lateral position [
This technique is a novel combination of minimally invasive techniques which could maintain the same objective as traditional decompression and extended fusion without changes of patient’s position. But with reduced trauma and morbidity to the patient. Limitation of the combination of various techniques is the surgeon may need more experience in each technique to effectively combined these techniques together.
Direct decompression and indirect decompression could be achieved by endoscopic discectomy-assisted OLIF for ASDis at L5-S1 with migrated disc herniation. Posterior fixation with double trajectory CBT screws is a minimally invasive option to reduce surgical trauma for the patient. Screws insertion on lateral position with intraoperative navigation decreased positioning time and could increase accuracy for double trajectory screw.
Preoperative MRI showed down migrated disc in sagittal cut Ⓐ. The migrated disc was on left side and compress S1 traversing nerve root Ⓑ.
Operative field. The patient was on right lateral decubitus position with slightly flexed hip and flexed operating table to increase interval at L5-S1 level Ⓐ. Oblique incision 3 cm in length was planned at 2 fingerbreadths anterior to ASIS Ⓑ. Endoscope was introduced through self-retaining retractor which was used for OLIF procedure Ⓒ. Posterior fixation was done in the same lateral position. The sterile spheres and reference frame were attach to left iliac crest with sterile adhesive tape Ⓓ.
Endoscopic discectomy. Transcorporeal tunnel was done by hand drill Ⓐ. Endoscopic discectomy fluoroscopic view Ⓑ.
Post-operative radiograph showed improved disc height, foraminal height and lumbar lordosis.
Post-operative MRI showed removed migrated disc in axial Ⓐ and sagittal Ⓑ view.