The Anatomy Studies And Curative Effect Of Treatment For Unstable Posterior Pelvic Ring Via Lateral-rectus Approach

Background:The incidence of unstable pelvic ring fractures are increasing year by year with the development of social economy and transportation.Sacroiliac joint disruption was commonly caused by high-energy trauma and was always serious due to association with multiorgan injury. Sacrum is cancellous bone and sacral plexus in the basin surface is covered by internal iliac artery and internal iliac vein branch. The incidence of lumbosacral plexus damage complicated with pelvic fracture was around from 0.75 to 15 per cent, and it was raised to around 50 per cent while the fracture around sacroiliac was with obvious displacement. In addition to the controversy of operative initial treatment of this neurological damage, Thus, surgical exploration may lead to fatal bleeding and this area is considered to be the "forbidden zone".Conservative therapy were more used to complex pelvic fractures,but, the incidence of complications such as malunion and traumatic arthritis is very high.The open reduction and internal fixation remained the "gold-standard" treatment, The main internal fixation methods to sacroiliac joint fracture and dislocation include sacroiliac screw, Sacroiliac joint anterior/Posterior plate and intrasacral rod, the effects of intrasacral rod are worst, Sacroiliac screw generally applies to preoperative traction has to reset the sacroiliac joint fracture and dislocation, But because of the complicated anatomical structure around the sacroiliac joint and its special mechanism of injury, the effect of closed reduction often not ideal, Therefore open reduction and internal fixation are still used for the patients with obvious displacement of fracture,there are many advantages of anterior approach for reduction and fixation of sacroiliac joint include Supine position does not affect other parts such as merger lung injury in patients with treatment, The anterior pelvic ring and posterior pelvic ring could be performed reduction and fixation at the same time. the infection is more lower than posterior approach, open reduction and internal fixation with anterior approach in the treatment of sacroiliac joint injury has been widely used, one of the key factors for clinical surgical reduction effect is fracture enough exposure, it provides broad field of vision for surgery.The traditional surgical approach for unstable pelvic fracture was anterior ilioinguinal approach,Recently, modified Stoppa approach is becoming ideal approach for pelvic and acetabulum fractures,but, it still exist deficiency in fixsion of the sacroiliac joint. With a thorough knowledge of the anatomy of the pelvis, we designed a new surgical approach which through the extraperitoneal space to reduce the pelvic fracture,However, large blood loss, trauma and complications of these extensive approaches can be avoided. Comparing with Stoppa approach, this approach can provide a direct operative vision for fracture reduction and neurolysis.Nowdays,more attention has been paid to the lumbosacral plexus injury combined with pelvic fractures,there are still controversial about method of treatment.Lumbosacral plexus damage was closely related to its anatomy and the mechanisms of the damage included compressive, traction and avulsion. According to the difference of mechanisms and the severity of the injury, the treatment and prognosis were various. Denis et al believed that an early surgical neurlysis should be performed while patients with sacral fracture complicated with drop foot and surgical treatment should be recommended while they complicated with vesicorectal disorder.In our opinion, For obvious nerve press-fitting, pull injury, Early surgery can create a good environment to neurological recovery, is beneficial to the recovery of neural function.Objectives:1.Based on the anatomical study. Position and variation of anatomical structure of the hypogastrie abdominal wall and pelvic cavity were observed in 10 cadaveric adults(20 sides), And the important neuroanatomical structure refinement measure.To perform an anatomical study on lateral-rectus to fractures of the pelvis in an attempt to testify feasibility of the approach.2. To investigate lateral-rectus approach for the treatment of unstable pelvic fracture complicated with neurological deficit and its curative effects.Methods:1. (Anatomical research of lateral-rectus approach for sacroiliac joint disruption)Position and variation of anatomical structure of the hypogastrie abdominal wall and pelvic cavity were observed in 10 cadaveric adults(20 sides), to expose the anterior rectus sheath, obliquus externus abdominis, inferior epigastric artery, arcuate line, the above superficial ring and the spermatic cord in male patients (or the round ligament in female patients) within the inguinal ligament. An adequate exposure included the pelvic ring from the quadrilateral plate to sacroiliac joints, quadrilateral plate, ala of ilium and most part of the medial side of the posterior column of acetabular is obtained by the lateral-rectus approach. Then horizontal distances between anterior branches of lumbar nerves 4,5, lumbosacral trunk(LST)and sacroiliac joint were measured with a caliper.2. Lateral-rectus approach in the treatment of sacroiliac joint disruption:clinical application and outcomeCombining with practice on autopsy,To investigate lateral-rectus approach for the treatment of sacroiliac joint disruption and its curative effects.36 patients with sacroiliac joint disruption was treated via the lateral-rectus approach. X-ray and CT scan were performed to investigate the reduction of fracture, The follow-up evaluation of fracture reduction was based on Matta score. All patients was followed up around 4 to 12 months, the postoperative function recovery evaluated by the Majeed score.3. The curative effect of treatment for unstable pelvic fracture complicated with neurological deficit via lateral-rectus approach.12 patients with unstable pelvic fracture complicated with neurological deficit were included in this study.After general anesthesia, the sacroiliac joint was exposed on the lateral side of lumbosacral trunk via the lateral-rectus approach, After reduction of the sacral fracture and neurolysis, the sacroiliac joint was fixed with a plate or sacroiliac screws. X-ray and CT scan were performed to investigate the reduction of fracture. The clinical outcomes were evaluated according to the British Medical Research Council (BMRC)evaluation criteria of sensation and movement function.Results:1. According to the anatomical study, Approaching to the anterior of sacroiliac joint, there was an operative window between femoral vessels, spermatic cord and the iliopsoas muscle to expose sacroiliac joint, obturator nerve, umbosacral stem and internal iliac vessels while straining abdominal muscles, iliac vessels and intraperitoneal tissues to the medial and iliopsoas to the lateral. The S1 vertebra was posterior to median sacral vessels and iliac vessels, straining which to lateral can expose S1 and S2 foramen. Via this operative window, we can perform the reduction of sacral fracture and neurolysis. The distance between the lumbar nerve 5 as it exits from the intervertebral foramen and the sacroiliac joint were (23.56±4.30)mm left and (23.69±3.41)mm right, the distance between anterior branches of lumbar nerve 4 branch and the sacroiliac joint at the level where the lumbar nerve 5 exits the intervertebml foramen were (17.97±1.58)mm left and (17.49±1.49)mm right. the distance between the beginning of the LST and the sacroiliac joint, the distance of the LST to the sacroiliac joint at the promontorium were 14.34±2.51)mm left and (13.81±2.21)mm right, the proximity of the LST to the sacroiliac joint at the pelvic brim were (12.19±1.98)mm left and (12.22±1.55) mm right.there are No significant statistical difference between left and right side(P>0.05).2. The patient was in supine position. After general anesthesia, the sacroiliac joint disruption was treated via the lateral-rectus approach. A the mean skin incision was (9.6±1.4) cm(8cm-10cm). The average surgical time was (106.47±39.02) min (75 min to 320 min) and the mean blood loss was (586.35±74.20) ml (140 ml to 2350 ml). Postoperative X-ray and CT indicated an excellent reduction of fracture. No complication was observed. All patients was followed up around 12 to 36 months (average 18 months) and found all patients had a successful fracture union. According to Matta score, anatomical reduction of the fracture was achieved in 28, perfect in 6 and imperfect in 2. the postoperative hip function recovery well and fracture healing occurred. According to the Majeed score,26cases were excellent,7 good, and 1 fair after operation. The patient was in supine position. After general anesthesia, The patient with unstable pelvic fracture complicated with neurological deficit was treated via the pararectus approach.11 patients of this study underwent the operation successfully. Otherwise, one operation was terminated due to the union of sacral fracture and the occlusion of S1 foramen, thus the neurolysis cannot conduct. The average surgical time was (195.70±37.20) min (110 min to 355 min) and the mean blood loss was(1550±324.50)ml (440 ml to 2760 ml). Postoperative X-ray and CT indicated an excellent reduction of fracture. No complication was observed. All patients was followed up around 12 to 30 months (average 24 months) and found all patients had a successful fracture union (8-12 months). The neurological examination was performed at the last follow-up and found, The neurological outcome was excellent in 7 patients, good in 3 and unchanged in 1 in the group.Conclusions:1. Based on the anatomical study, we Confirmed that the lateral-rectus approach can be used to reduction and internal fixation the sacroiliac joint fracture and dislocation,there exist security space of operation,what’s more, the approach provides a new way for the treatment of nerve injury caused by sacroiliac joint damage, Anatomical study found L4, L5 nerve roots on the surface of the wing of the sacrum bone vertical distance decreasesing, And after L5 nerve root out of the intervertebral foramen, almost close to the wing of the sacrum bone surface, But in the process of fresh autopsy,we found fresh cadaver specimen organization has good elasticity, There is no obvious change of Nerve, blood vessel, muscle, and other important tissue, Although L5, L4almost closed to the the sacral wing surface, But after the separation of the surrounding soft tissue carefully,we found L4, L5, lumbosacral trunk, S1 nerve root has good elasticity and there is no obvious slip when activited the lower limbs, So the author believes that before the sacroiliac joints have enough space to place under the nerve root of internal fixation and has smaller effects of nerve.2. All the patients were treated under general anesthesia. Patients were positioned supine on a radiolucent operating stable. this approach is with a clear operative field and a simple operation, combined with acetabular fractures, After the fracture site was revealed, the acetabular fractures was reduced by different operating window. comparing with ilioinguinal approach. excessive traction of vessels and nerves can be avoided due to the longitudinal exposure and less side injuries are induced in this approach. Approaching to the anterior of sacroiliac joint, there was an operative window between femoral vessels, spermatic cord and the iliopsoas muscle to expose sacroiliac joint, obturator nerve, umbosacral stem and internal iliac vessels while straining abdominal muscles, iliac vessels and intraperitoneal tissues to the medial and iliopsoas to the lateral. Via this operative window, we can perform the reduction of sacral fracture and neurolysis. This surgical approach had overcome the disadvantages of small incision, inadequate exposure and difficult to reduce in ilioinguinal approach and modified Stoppa approach. single lateral-rectus approach to reduce double column acetabular fractures combined with quadrilateral plate displacement. This surgical approach was performed in supine position to help the intraoperative anesthesia. The anterior pelvic ring and posterior pelvic ring could be performed reduction and fixation at the same time. After the fractures reduction, aponeurosis of obliquus externus and internal abdominis were sutured. Limitations of the current study should be acknowledged. First, this study included a relatively small number of patients and a large prospective study incorporating a control group must be undertaken. Also, longer-term follow-up will be required to define the durability of treatment of this surgical approach.