Anatomic Study And Clinical Appilication Of Lower Lumbar Minimal Invasive Surgery

Background and ObjectionModern developed surgery require surgery to be more precise, humane, intelligent, digital, minimally invasive, to reduce the trauma of surgery, to speed up recovery, to benefit to patients.so it get more difficult for the surgen. Traditional open surgery has gradually been replaced by alternative minimally invasive surgery. The traditional study of anatomical specimens generally can not meet the needs of minimally invasive surgery. Endoscopic anatomy is even more necessary and more urgent. The more familiar with microscopic anatomy, the shorter of minimally invasive surgical learning curve.Lumbar degenerative diseases (Disc degenerative disease, DDD) are common in our life. They are including lumbar disc herniation, lumbar spinal stenosis, lumbar degenerative spondylolisthesis, lumbar discogenic low back pain, lumbar spondylolysis, lumbar degenerative scoliosis (degenerative scoliosis, DS) and so on. Lumbar disc herniation is more common, and more complicative. Minimally invasive treatments of lumbar disc herniation are including intervention, endoscopic surgery, and open surgery.Currently the main minimally invasive surgeries of lower lumbar DDD are including minimally invasive surgery laparoscopic anterior lumbar fusion surgery (Anterior lumbar inter-vertebrae fusion, ALIF), axial lumbar fusion (AxiaLIF), lumbar artificial disc replacement surgery (lumbar disc arthroplasty, LDA), the lateral percutaneous endoscopic lumbar discectomy (percutaneous lumbar endocscopic disc-ectomy PLED),Direct lumbar inter-vertebrae fusion, DLIF), posterior lumbar discectomy (Micro endoscopic disc-ectomy, MED) and full endoscopic lumbar discectomy (Full-endoscopic lumbar disc-ectomy, FLD). The lateral percutaneous endoscopic lumbar discectomy contain YESS and TYSYSS technology.The aim of this study is to explore the low lumbar endoscopic anatomy to prevent surgical complications, including blood vessels injury, nerve lesion, ureteral injury, sympathetic trunk damage.MaterialsMethods20cases of arterial perfused with red latex and fixed cadavers (12males,8females). All the cadavers are adult specimens, found no other pathological conditions affecting the lumbar anatomy.60cases of lumbar CT data and MRI data (30males and30females), mean age was45(24to57) years, with640-slice CT scan and1.5TMRI scan, CTA to reconstruct the anatomy of the lumbar spine by three-dimensional reconstruction. Measured the distance in the PAC system. Save the data in DICOM format, import MIMICS software reconstruction of blood vessels and Lumbar structure.MethodsAnterior approach:Retroperitoneal revealed abdominal aorta, inferior vena cava, iliac artery and vein, ureter, sympathetic. Measured the distance between abdominal aorta and sympathetic (left side in L3/4), the distance between external iliac vein and sympathetic (right side in L3/4), the distance between the ureter and sympathetic, explored the distribution of segmental artery and ALIF safe area.Lateral approach:Paraspinal muscle around the lumbar foramen total removal, clean up the ligament, only remained the exsting nerve (existing nerve, EN) and the lower lumbar segmental arteries (lower lumbar segment artery, LLSA). The low lumbar foramen zones fully revealed. Measured lumbar segmental artery diameter and its distribution and branch. L3to L5lumbar segmental artery were recorded L3A, L4A, and L5A. Measured the distance between upper facet and exit nerve roots on the plane of disc, recorded as DL3N, DL4N, and DL5N. Measured the distance between the exit nerve root and the edge of the disc. Measured the weight of intervertebral foramen on the plane of disc, and the maximum weight of the intervertebral foramen.PosteriorSpatium intermusculare approach:Prone position, midline skin incision, turned the flap to the outside to remove subcutaneous fat layer, revealing fascia, turned fascia outside by a retractor, exposed paraspinal muscle. Carefully identify the multifidus muscle, longest muscle and iliac rib muscle, searched for potential muscle gap. Revealed the structural features inside the different muscle gap approach.Posterior midline approach:Spilited from the pedicle level by saw, open spinal canal, measure the distance between nerve root and spine canal midline,weight of safe working hemline at the disc level, vascular distribution of intraspinal. Randomly selected full-endoscopic lumbar discectomy surgery video40minutes to reveal lumbar laminectomy gap approach stucture.Clinical applicationsCompared percutaneous foramial endoscopic lumbar discectomy(PELD) and full endoscopic lumbar discectomy (FLD)with the same period MED surgery, to find out the risk factor and the effect the PELD and FLD and to come up with the solutions.ResultsAnterior approachL3/41evel, on the left, the distance between the abdominal aorta and sympathetic is13.5±3.0mm.On the right, the distance between the inferior vena cava and sympathetic is9.2±2.6mm.When the vessel bifurcation is above L4/5level, on the right the distance between the external iliac vein and sympathetic is6.4±1.4mm. On the left the distance between external iliac artery and sympathetic is6.4±1.2mm.When the vessel bifurcation is under L4/5level, on the left, the distance between the abdomen aortic and sympathetic distance is12.5±3.0mm. On the right, the distance between he inferior vena cava and sympathetic is10.8±2.2mm.Ureters were retroperitoneal Traveling with spermatic vein. The average distance between the left ureter and abdominal aorta is3.5cm, the average distance between the right ureter and vena cava is2.8cm. Because of relatively large bilateral ureteral activity, the distance get differently, at the L5S1level the distance get larger, it is from2-4cm sometime.Segmental artery directly come from the abdominal aorta, walking in the middle of the lumbar vertebral, L3A is largest, the diameter is1.8±0.3mm, the smallest is L5. Sacral artery relatively large vary,15cases come from from the abdominal aorta,2cases from left iliac artery,3cases from right iliac artery.Lateral approachLower lumbar segmental arteries appeared at all the lumbar foramen, and always have3branches, the branches are around the exsting root.the large two branches located below the transverse process and the top of upper facet, and small branches locate below the upper facet. The LSA diameter:L3A was1.8±0.3mm, L4A1.6±0.4mm, L5A1.3±0.2mm.The distance between the exsting nerve and upper facet at the different disc level:L3/4was3.5±1.2mm, L4/5was4.2±1.5mm, L5S1was4.6±1.0mm, the longest distance is only5.6mm, less than7.5mm.Transverse diameter of intervertebral foramen:L3/4is8.6±2.0mm at disc level, intervertebral foramen maximum diameter is9.4±4.5mm. L4/5is9.5±3.0mm at disc level, the maximum diameter of the intervertebral foramen is10.2±3.5mm. L5/S1is8.2±2.2mm9.5±3.0mm at disc level,the maximum diameter of the intervertebral foramen is9.6±3.2mm.Ascending lumbar vein location and distribution:Ascending lumbar vein foramen is at verteberal periosteal surface. Psoas muscle cover the ALV. Ascending lumbar vein communicates Iliac vein in the end mostly. Ascending lumbar vein often travel at the surface of the exiting nerve roots.Lumbosacral plexus (lumbosacral plexus) location and distribution:12th thoracic nerve branch, part of the composition of L1to L3nerve anterior branch and the former branch of L4nerve compose the Lumbosacral plexus. The distance between EN and the midpoint of the disc,11.5±1.2mm (L3) at L3/4level,10.8±1.5mm (L4) at L4/5level.The distance between the sympathetic and the disc center:12.5±1.6mm (L3) at L3/4level,14.2±2.5mm (L4) at the L4/5level. The distance between the centers of disc and transforaminal lumbar plexus:10.5±2.0mm at L3/4,9.2±1.5mm at L4/5.Posterior approachPosterior Muscle gap approach:Wiltse muscle gap is between multifidus dorsi muscle and longest muscle. The LIMP gap between longest muscle and iliocostalis muscle. The Watkins gap between iliocostalis muscle muscle and quadratus lumborum. The average distance waist3/4level lumbar midline to Wiltse gap is2.0cm at L3/4level,2.5cm at L4/5level,2.8cm at L5/S1level.The average lumbar midline to LIMP gap distance3.5cm at L3/4level,4.0cm at L4/5level,4.2cm at L5/S1level.Wiltse gap is filled with fat, few vessels pass through, but LIMP gap is smaller and some vessel branches pass through.Spinal anatomy:Lower lumbar nerve Travele differently. The higher level, the shorter and flater path. The The higher level, the lower original point. L4lumbar nerve root canal original from spine at the level of the bottom half of the L4vertebrae, L5nerve root issued a relatively high point, usually originating at the middle of14/5disc, S1nerve root is almost vertical, also issued a relatively highest point, usually originating at the bottom of the L5/S1disc.Intraspinal safety triangle (Safe triangle):the outside boundary is upper nerve root, medial boundary is dural sac and nerve root sleeve, the lower boundary is the lower edge of the corresponding disc. Safety Triangle bottomline:5.6±1.4mm at L4/5level.6.8±1.8mm at L5/S1level.Laminar space measure:Height:9.5±1.4mm at L3/4level,11.5±2.7mm at L4/5level and11.8±1.4mm at L5/S1level.Width:6.4±1.8mm at L3/4level,8.6±2.5mm at L4/5level and10.4±2.6mm at L5/S1level.ConclusionAnterior approachL3/4AND14/5ALIF surgery, it is recommended to enter from the left, to confirm the anatomical relationship by palp abdominal aorta through the left side, found the ureter on the inside of the abdominal aorta, retracted ureter and arteriovenous can reveal enough surgical workspace. In lumbar disc excision should pay attention not to exceed the outer edge of the psoas muscle, where lumbar sympathetic trunk located. Also some small branches of segmental blood vessels is in front of lumbar intervertebral disc, be attention not to injury them. When a L5S1sacral ALIF surgery, generally confirm the location of the sacral artery in the preoperative, intraoperative attention ligation. Because of the sacral artery greater variability, it can not be served as the midline.Lateral approachPLED is a new technology, it get inspiring clinic results.But the technoly has it own complictions.POD is its unique complications. Enlarge foramen is effective method to reduce the POD, be careful not to damage the lumbar vein and lumbar artery branches in the enlarge foramen procedure. Extreme lateral lumbar interbody fusion (XLIF) or directly lumbar interbody fusion (DLIF) is a new minimally invasive lateral lumbar fusion technology, has a good safety performance. The most complication is the lumbar plexus damage. The possibility of vascular injury is small。 L4/5DLIF is more complication than L3/4.Do not omit electrical nerve monitoringClinical applicationsThe key of percutaneous transforaminal lumbar discectomy surgery is enlargermen of transforamia, it is a very important step to avoid avoid nerve root injuryand postoperative numbness (POD). Posterior endoscopic discectomy require the whole laminar space greater than8mm, intraoperative nerve root compression must be avoided.