Tuanjiang Liu

Posterior atlantoaxial fixation: a review of all techniques

BACKGROUND CONTEXT Posterior atlantoaxial fixation is an effective treatment for atlantoaxial instability. Great advancements on posterior atlantoaxial fixation techniques have been made in the past decades. However, there is no article reviewing all the posterior atlantoaxial fixation techniques yet. PURPOSE The aim was to review the evolution and advancements of posterior atlantoaxial fixation. STUDY DESIGN This was a literature review. METHODS The application of all posterior fixation techniques in atlantoaxial stabilization, including wiring techniques, interlaminar clamp fixation, transarticular fixation, screw-plate systems, screw-rod systems, and hook-screw systems, are reviewed and discussed. Recent advancements on the novel technique of atlantoaxial fixation are described. The combination of the C1 and C2 screws in screw-rod systems are described in detail. RESULTS All fixation techniques are useful. The screw-rod system appears to be the most popular approach. However, many novel or modified fixation methods have been introduced in recent years. CONCLUSIONS Great advancements on posterior atlantoaxial fixation techniques have been made in the past decades. The wiring technique and interlaminar clamps technique have fallen out of favor because of the development of newer and superior fixation techniques. The C1-C2 transarticular screw technique may remain the gold standard for atlantoaxial fusion, whereas screw-rod systems, especially the C1 pedicle screw combined with C2 pedicle/pars screw fixation, have become the most popular fixation techniques. Hook-screw systems are alternatives for atlantoaxial fixation.

The difference in superior adjacent segment pathology after lumbar posterolateral fusion by using 2 different pedicle screw insertion techniques in 9-year minimum follow-up.

Study Design. A prospective study was performed. Objective. To test the hypothesis that different pedicle screw insertion positions would increase the likelihood of superior adjacent segment degeneration (ASD). Summary of Background Data. Lumbar fusion surgery is a widely accepted treatment of lumbar diseases, such as lumbar stenosis, trauma, tumor, and spondylolisthesis. Fusion and clinical success rates have increased because of improvements in instrumentation and bone graft material. In contrast, numerous complications and problems of fusion surgery have been reported, with ASD being one of the most important. Methods. This prospective study included 210 patients with low-grade isthmic spondylolisthesis. From January 1999 to December 2003, patients were randomized underwent posterolateral fusion using 2 different pedicle screw insertion positions. The patients were followed up postoperatively and were assessed with regard to radiological and clinical outcomes. Radiological outcomes were assessed mainly on the basis of disc degeneration, facet joint degeneration, and bone fusion. Clinical outcomes were evaluated mainly with the use of visual analogue scale for pain and the Oswestry Disability Index. Results. A total of 178 of 210 (84.7%) patients were available for at least 9-year radiological and clinical follow-up data: 85.3% (87/102) patients in group A and 84.3% (91/108) patients in group B. Bone fusion was achieved in all patients at the last follow-up. ASD was proven in 110 (61.8%) of 178 patients. The incidences of radiographical and symptomatic ASD were 57.9% (103/178) and 3.9% (7/178), respectively. The incidence of ASD in group B was significantly lower than that in group A. Results of clinical outcomes showed lower visual analogue scale and Oswestry Disability Index scores in 2 groups than preoperative scores, but group B had greater improvement on the Oswestry Disability Index scores than group A in patients with ASD. Conclusion. The degeneration of superior adjacent segment is closely related to the position of the pedicle screws during lumbar fusion surgery. The position of the pedicle screw farther from the facet joint surface can reduce the degeneration of superior adjacent segment. Level of Evidence: 3

A Comparison Between Unilateral Transverse Process-pedicle and Bilateral Puncture Techniques in Percutaneous Kyphoplasty

Study Design. A prospective comparative study. Objective. To assess the clinical and radiological outcomes for the treatment of osteoporotic vertebral compression fractures using unilateral transverse process-pedicle and bilateral percutaneous kyphoplasty (PKP). Summary of Background Data. PKP is a widely used vertebral augmentation procedure for treating painful vertebral compression fractures. A percutaneous bilateral approach is typically used to access the vertebral body. Many previous studies have reported excellent clinical results with PKP. In contrast, numerous complications and problems have also been reported, such as puncture difficulty, cement leakage, and adjacent vertebral fracture. Methods. This prospective study included 316 patients with single-level lumbar osteoporotic vertebral compression fracture, 224 females and 92 males with a mean age of 71.5 years. Randomized patients underwent PKP using 2 different puncture techniques. The patients were followed up postoperatively and were assessed mainly with regard to clinical and radiological outcomes. Clinical outcomes were evaluated mainly using the visual analogue scale for pain and 36-Item Short Form Health Survey (SF-36) questionnaire for health status. Radiological outcomes were assessed mainly on the basis of radiation dose, bone cement distribution, vertebral body height, and kyphotic angle. Results. Patients were followed up from 12 to 28 months, with an average of 16.8 months. One hundred fifty-eight patients were treated with unilateral method and 151 patients were treated with bilateral method. In the unilateral group, the volume of the injected cement and radiation dose were significantly less than that in the bilateral group. All patients in both groups had significantly less pain after the procedures, compared with their preoperative period pain. No statistically significant differences were observed when visual analogue scale and 36-Item Short Form Health Survey were compared between the groups. Both unilateral and bilateral groups showed insignificant decrease in the kyphotic angle during the follow-ups. The kyphotic angle in the unilateral group improved more significantly than in the bilateral group. In the bilateral group, 16 patients had obvious pain in the puncture sites at 1 month postoperatively caused by facet joint violation. With local block treatment, the pain disappeared in all patients at the last follow-up. Conclusion. Both bilateral and unilateral PKP are relatively safe and provide effective treatment for patients with painful osteoporotic vertebral compression fracture. However, unilateral PKP received less radiation dose and operation time, it also offered a higher degree of deformity correction and resulted in less complication than bilateral PKP. Level of Evidence: 3

Prospective, Self-controlled, Comparative Study of Transposterior Arch Lateral Mass Screw Fixation and Lateral Mass Screw Fixation of the Atlas in the Treatment of Atlantoaxial Instability.

Study Design: A prospective self-controlled study. Objective: The aim of the present study was to compare the application and clinical outcomes of transposterior arch lateral mass screw and lateral mass screw fixation of the atlas in the treatment of atlantoaxial instability. Summary of Background Data: Atlas posterior screw fixation techniques comprise transposterior arch lateral mass screw fixation and lateral mass screw fixation. Previous studies have focused mainly on the feasibility of the anatomy and the biomechanics of the methods. Methods: From June 2006 to February 2011, 66 patients with atlantoaxial instability were randomly assigned for treatment with transposterior arch lateral mass screw or lateral mass screw fixation of the atlas, combined with axis pedicle screw fixation. Patients were followed up regularly. The operation time, blood loss, intraoperative complications, Japan Department of Orthopedics Association Score, visual analog scale score, and bone fusion rates were recorded. Results: The operation was successful in all 66 cases, with all patients showing improvement in clinical symptoms. There were significant differences in operation time and blood loss between the 2 groups (P<0.001). The mean follow-up time was 49 months. At the final follow-up, the Japan Department of Orthopedics Association score was significantly better than the preoperative score (mean, 13.5; P<0.05). The mean postoperative improvement rate was 88.2% and the mean visual analog scale score was 1.9; both results were significant as compared with preoperative results (P<0.05). Bone fusion was achieved within 6 months after operation. No screw loosening, shifting, breakage, or atlantoaxial instability was observed. Six patients with atlas lateral mass screw placement had burst bleeding of C1–C2 venous plexus during surgery. Five patients had immediate pain and numbness at the occipitocervical region. Conclusions: Atlas transposterior arch lateral mass screw fixation is less invasive, simple, has fewer complications, and offers good fixation results for atlantoaxial instability as compared with lateral mass screw fixation.

Successful percutaneous retrieval of a large pulmonary cement embolus caused by cement leakage during percutaneous vertebroplasty: case report and literature review.

Study Design. A case report and literature review. Objective. To present a case of dynamic detection of a large pulmonary cement embolus as it formed and migrated during percutaneous vertebroplasty, which was successfully managed by percutaneous endovascular retrieval. Summary of Background Data. Pulmonary embolism resulting from cement leakage after percutaneous vertebroplasty to treat osteoporotic vertebral compression fracture has been described rarely; however, the frequency of this complication may increase secondary to the expanding use of percutaneous vertebral augmentation techniques. Methods. The formation of a large embolus of acrylic cement and its migration into the pulmonary artery was observed in real time in a 55-year-old female with osteoporotic vertebral compression fracture of L4 during percutaneous vertebroplasty. Results. Pulmonary arteriography confirmed the presence of the cement embolism in the right pulmonary artery during the operation. Percutaneous endovascular retrieval of the cement fragments was performed successfully via an interventional catheter procedure and subsequent incision of the femoral vein. The patient made an uneventful recovery. Conclusion. As illustrated by our case, large cement emboli may be primarily associated with technical aspects of the surgery. When considering the appropriate treatment strategy, percutaneous endovascular retrieval may be considered first. However, risks and benefits should be carefully evaluated on a case-by-case basis. Level of Evidence: N/A

Two-year follow-up evaluation of surgical treatment for thoracolumbar fracture-dislocation.

Study Design. A randomized, controlled clinical trial. Objective. This randomized controlled clinical trial was aimed at comparing the clinical outcomes of combined posteroanterior (P-A) fusion and transforaminal thoracic interbody fusion (TTIF) in cases of thoracolumbar fracture-dislocation. Summary of Background Data. The optimal treatment strategy for thoracolumbar fracture-dislocation remains controversial. Methods. Sixty-one patients presenting with acute fracture-dislocation of the thoracolumbar joint between March 2010 and December 2011 were enrolled and randomly assigned to the P-A or TTIF group. The radiological outcome was assessed by acquiring radiographs in the standing position and computed tomographic scans. The clinical outcome was measured in terms of the American Spinal Injury Association score, visual analogue scale score, and Oswestry Disability Index. Moreover, we assessed the severity of overall morbidity and morbidity at the donor site in the 2 patient groups. The Student t and &khgr;2 tests were used for the analysis of independent variables and categorical data, respectively. Results. Only 57 of the enrolled patients were available for the required 24-month follow-up period, 27 underwent TTIF and 30 underwent P-A fusion. Both treatments were similar with respect to the fusion rate, extent of decompression, loss of correction, rate of instrumentation failure, American Spinal Injury Association score, visual analogue scale score, and Oswestry Disability Index (P > 0.05). However, the blood loss, operating time, and rate of perioperative complications were greater in the P-A group than in the TTIF group (P < 0.05). Conclusion. The clinical and radiological outcomes were similar for both the treatment procedures. However, our findings suggest that TTIF allows for safe interbody fusion and circumferential decompression, requires only a posterior approach, and is associated with a lower incidence of surgery-related complications. Level of Evidence: 2

Tuberculous Spondylitis Following Kyphoplasty: A Case Report and Review of the Literature

AbstractTuberculous spondylitis of the augmented vertebral column following percutaneous vertebroplasty or kyphoplasty has rarely been described. We report an unusual case of tuberculous spondylitis diagnosed after percutaneous kyphoplasty (PKP).A 61-year-old woman presented to our institution complaining of back pain following a fall 7 days before. Radiologic studies revealed an acute osteoporotic compression L1 fracture. The patient denied history of pulmonary tuberculosis (TB) and there were no signs of infection. The patient was discharged from hospital 4 days after undergoing L1 PKP with a dramatic improvement in her back pain. Two years later, the patient was readmitted with a 1 year history of recurrent back pain. Imaging examinations demonstrated long segmental bony destruction involving L1 vertebra with massive paravertebral abscess formation. The tentative diagnosis of tuberculous spondylitis was made, after a serum T-SPOT. The TB test was found to be positive. Anterior debridement, L1 corpectomy, decompression, and autologous rib graft interposition, and posterior T8-L4 instrumentation were performed. The histologic examination of the resected tissue results confirmed the diagnosis of spinal TB. Anti-TB medications were administered for 12 months and the patient recovered without sequelae.Spinal TB and osteoporotic vertebral compression fractures are similar clinically and radiologically. Spinal surgeons should consider this disease entity to avoid misdiagnosis or complications. Early surgical intervention and anti-TB treatment should be instituted as soon as the diagnosis of spinal TB after vertebral augmentation is made.

An assessment system for evaluating the severity of thoracolumbar osteoporotic fracture and its clinical application: A retrospective study of 381 cases

OBJECTIVE We put forward an assessment system of thoracolumbar osteoporotic fracture (ASTLOF) evaluating the severity of thoracolumbar osteoporotic fracture. This study was to investigate its efficacy in guiding clinical practice. METHODS Three hundred and eighty-one patients with thoracolumbar vertebral osteoporosis fracture admitted to the hospital from January 2010 to December 2011 were enrolled in the study. All cases were evaluated by ASTLOF including evaluation of morphological changes, MRI, bone mineral density and pain. The patients were treated with different methods according to ASTLOF score. All patients were followed up on a regular basis. The treatment results were assessed by VAS and ODI. RESULTS All patients were followed up with an average of 20.1 (range: 6-30) months. There were 91 cases of ASTLOF score<4 points. Their average VAS score decreased from 8.0 ± 1.7 points to 2.0 ± 1.3 with statistical significance (P<0.05) and the average ODI score decreased from 69.5 ± 2.8 to 38.1 ± 1.5 (P<0.05). One hundred and thirty-two cases were with ASTLOF score=4, with the average VAS score decreased from 8.2 ± 1.4 to 1.9 ± 1.2 (P<0.05) and the average ODI score decreased from 71.5 ± 3.7 to 36.2 ± 2.5 (P<0.05). There were 158 cases of ASTLOF score ≥ 5, with the VAS score decreased from 8.0 ± 1.7 to 2.0 ± 1.3 and the ODI score decreased from 69.5 ± 2.8 to 38.1 ± 1.5. CONCLUSIONS ASTLOF based on the severity of thoracolumbar osteoporotic fracture was suggested to be helpful in guiding clinical practice.

Cause Analysis of Open Surgery Used After Percutaneous Vertebroplasty and Kyphoplasty

Background The aim of this study was to analyze reasons why open surgery was done after percutaneous vertebroplasty and kyphoplasty. Material/Methods Patients (587 vertebral bodies) treated with percutaneous vertebroplasty or kyphoplasty in the Xi’an Honghui Hospital of Shanxi Province from January 2008 to January 2012 were retrospectively analyzed and 13 patients were enrolled in the study. These 13 patients had serious adverse events after percutaneous vertebroplasty or kyphoplasty. Their average age was 64.5 years old. Nine patients had spinal cord injury and 4 had nerve root injury. All the patients underwent open surgery within 4–12 h after definitive diagnosis. Results All 13 cases were followed up (average time 14.1 months, range 3–47 months). Reasons for open surgery included cement extravasation (6 cases, 46.2%), puncture mistake (3 cases, 23.1%), and false selection of indications (4 cases, 30.8%). At last follow-up, skin feeling was better than that before open surgery in 4 cases with nerve root injury, and muscle strength recovered to grade 5 (3 cases) and grade 4 (1 case). In 9 cases with spinal cord injury, 7 patients improved and 2 remained at the same ASIA level. Conclusions The main reasons for open surgery after percutaneous vertebroplasty and kyphoplasty were cement extravasation (the most common reason), puncture mistake, and false selection of indications.

Efficacy of rhBMP-2 versus iliac crest bone graft for posterior C1-C2 fusion in patients older than 60 years.

Few studies have specifically examined the efficacy of recombinant human bone morphogenetic protein-2 (rhBMP-2)/absorbable collagen sponge (ACS) in posterolateral lumbar spine fusion. The purpose of this study was to report the clinical outcomes in elderly patients treated with posterior C1-C2 fusion with iliac crest bone graft (ICBG) plus rhBMP-2/ACS vs ICBG alone. One hundred forty patients older than 60 years were enrolled in this prospective, randomized trial and underwent instrumented C1- C2 fusion. Patients were divided into 2 groups based on fusion material. The ICBG group comprised patients who received ICBG alone, and the rhBMP-2/ACS group comprised patients who received ICBG plus rhBMP-2/ACS. The groups were compared based on operative time, estimated blood loss, hospital length of stay, clinical results, perioperative complications, fusion rate, fusion time, and revision rate. There were no significant differences in operative time, estimated blood loss, length of stay, and intraoperative complications between the 2 groups. Improvements in visual analog scale scores and Japanese Orthopaedic Association scores over the 2-year follow-up period were similar between groups. The fusion rate was 82.4% (56 of 68) in the rhBMP-2/ACS group and 78.7% (52 of 66) in the ICBG group (P=.782). Mean fusion time was 11 days shorter in the rhBMP-2/ACS group (81.8±29.4 days) than in the ICBG group (92.9±23.7 days) (P=.034). There were more wound complications requiring treatment in the rhBMP-2/ACS group (n=6; 8.8%) than in the ICBG group (n=2; 3.0%), although this was not statistically significant (P=.118). The use of rhBMP-2/ACS for posterior C1-C2 fusion appears to result in a relatively shorter fusion time, but there may be an increased risk of posterior cervical wound complications.