Management of Andersson Lesion in Ankylosing Spondylitis Using the Posterior-Only Approach: A Case Series of 18 Patients

Clinical Observation of Posterior Approach for Surgical Treatment of Thoracolumbar Pseudarthrosis in Ankylosing Spinal Disorders

OBJECTIVE

The objective of this study was to evaluate the surgical effectiveness of posterior procedure with long segment stabilization for treating thoracolumbar pseudarthrosis associated with ankylosing spinal disorders (ASDs) without anterior fusion or osteotomy.

METHODS

Twelve patients with thoracolumbar pseudarthrosis in ASD were enrolled. All patients underwent posterior long-segment stabilization procedures. In some patients, the percutaneous technique or the aid of a robot or O-arm navigation was utilized for pedicle screw implantation. The clinical results were evaluated by means of the visual analog scale and Oswestry Disability Index. Radiological outcomes were evaluated for bone fusion, anterior column defect, local kyphotic correction, and position of the pedicle screws.

RESULTS

All patients experienced effective bone fusion at the sites of pseudarthrosis. The mean operative time was 161.7 ± 57.1 minutes, and the average amount of blood loss was 305.8 ± 293.2 mL. For 6 patients who underwent surgery with the assistance of a robot or O-arm navigation, there was no statistically significant difference observed in terms of operative time and mean blood loss compared to those who used the freehand technique (P > 0.05). The visual analog scale score, Oswestry Disability Index value, and mean local kyphotic angle showed significant improvements at the final follow-up (P < 0.05). The accuracy of pedicle screw placement was 96%.

CONCLUSIONS

Posterior surgery with long-segment fixation, without anterior fusion or osteotomy, can achieve satisfactory outcomes in ASD patients with thoracolumbar pseudarthrosis. The application of percutaneous techniques, as well as the assistance of robots or navigation technique may be a good choice for the treatment of pseudarthrosis in ASD patients.

Results of in situ fixation of Andersson lesion by posterior approach in 35 cases

STUDY OBJECTIVE

Due to the rarity of the Andersson lesion (AL), the literature is ambiguous regarding the type of surgical fixation, need for debridement and deformity correction. The purpose of this retrospective study is to evaluate the efficacy, feasibility and functional outcome of posterior fixation in AL.

MATERIALS AND METHODS

This study included 35 patients having thoracolumbar AL operated for in situ fixation and fusion with minimum of 24-month follow-up. VAS (Visual Analogue Score) back pain, ODI (Oswestry Disability Index), Frankel's grade were compared and analyzed. Union status was noted with complications.

RESULTS

The mean age of 35 patients was 56.34(± 11.3) years with average follow-up of 51.49 months. Two patients had AL at two levels. 27/37 AL were at discal level. Average estimated blood loss (EBL) was 276.43 ml and duration of surgery was 130.43 min. On an average, operated segments needed 7.77 screws. There were ten minor complications without long-term sequel. Neurological improvement was noted in 30 patients. Average preoperative VAS score improved from 8.69 to 3.14, ODI score improved from 68.76 to 18.77 at final follow-up which were significant (p < 0.05). There was significant improvement in Frankel's grading (Z = - 4.354, P = 0.00).

CONCLUSIONS

Surgical management of AL by posterior approach and posterior stabilization can give satisfactory results without the need of extensive anterior reconstruction, bone grafting or deformity correction procedures without added morbidity and complications.

Surgical Treatment of Andersson Lesion of the Lumbar Spine with Minimal Invasion: A Case Report

We present a 37-year-old female patient with AL of lumbar spine (L3-4) treated by OLIF combined with pedicle screw fixation (via Wiltse paraspinal approach) with relatively minimal invasion.

Treatment of ankylosing spondylitis complicated with a thoracolumbar Andersson lesion by posterior closed osteotomy, debridement and fusion through the fracture line

Background

An Andersson lesion (AL) is a fatigue fracture occurring across three columns in ankylosing spondylitis (AS), resulting in spinal pseudarthrosis (SP) formation, most commonly in the thoracolumbar segment. However, there is still great controversy and few reports on the best surgical method for the treatment of AS combined with thoracolumbar AL. The purpose of this study was to investigate the efficacy of posterior closed osteotomy, debridement and fusion through the fracture line for the treatment of this disease.

Methods

The clinical data of 13 patients (male 8, female 5, mean age 50.6 years) with AS combined with thoracolumbar AL treated with posterior closed osteotomy, debridement and fusion through the fracture line were retrospectively analysed. The following parameters of the full-length lateral spine radiographs were measured preoperatively and at the last follow-up: cervical 7 tilt (C₇T), global kyphosis (GK), thoracic kyphosis (TK), thoracolumbar kyphosis (TLK), local kyphosis (LK), angle of the fusion levels (AFL), lumbar lordosis (LL), pelvic incidence (PI), pelvic tilt (PT), sacral slope (SS) and sagittal vertical axis (SVA). The visual analog scale (VAS), Oswestry disability index (ODI) and Scoliosis Research Society-22 (SRS-22) scores were recorded preoperatively and at the last follow-up.

Results

The mean operation time was 345 min, the mean blood loss was 673 mL, and the mean follow-up time was 21.9 months. Compared with the preoperative values, the C₇T, GK, TK, TLK, LK, AFL, PT, SS and SVA values of all patients were significantly improved at the last follow-up (P < 0.05); GK improved from 81.62 ± 16.11 to 50.15 ± 8.55, with an average of 31° of correction (F = 75.945, P<0.001). The VAS, ODI and SRS-22 scores also significantly improved (P < 0.05). At the last follow-up, bone fusion was found in all fracture ends. One patient developed numbness in the lower limbs after surgery and recovered after 3 months of rehabilitation; none of the remaining patients experienced postoperative complications.

Conclusions

Posterior closed osteotomy, debridement and fusion through the fracture line completely removes the necrotic tissue around the SP, relieves symptoms, and corrects kyphosis simultaneously. It reduces the tension behind the fracture line or changes the tension into compressive stress, enabling stable repair of the fracture and avoiding anterior surgery. It is a safe and effective operation.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12891-022-05770-3.

An infected Andersson lesion presented with incomplete paraplegia in a patient with ankylosing spondylitis. A unique case report with literature review

INTRODUCTION

A relatively rare and unknown entity in patients with ankylosing spondylitis is the Andersson lesion (AL). It was first described by Andersson in 1937 as destructive vertebral or disco-vertebral lesion of the spine without history of trauma. AL may result from inflammation or stress fracture of the rigid spine, while there is no evidence for an infectious origin. To our knowledge, only one case with an infected AL has been published many years ago; we hereby present the second case, but the first one with severe neurologic deterioration.

CASE PRESENTATION

A 79-year-old male patient was presented to our emergency department and his neurological examination on admission revealed incomplete paraplegia below the Th10 level. Plain radiograms at the level of 10th thoracic vertebra revealed a lesion mimicking a severe vertebral fracture. The computed tomography confirmed the diagnosis of the AL and due to the significant local instability and the neurologic deficit, the patient underwent posterior decompression and stabilization. During decompression, we noticed purulence and extensive debridement was performed. The cultures of the Th10 pus revealed Enterococus sp, while the same pathogen was developed to urine cultures. The patient received intravenous antibiotics for 4 weeks, followed by per os antibiotic therapy. At the 18-month follow-up our patient had significant improvement of this functional status.

DISCUSSION

Most studies support that inflammatory or traumatic/mechanical (pseudarthrosis) etiology are the most possible causes of Anderson lesions. Possible neurological deterioration should be investigated and demonstrates significant spinal instability. The integrity of the posterior column should be investigated, and exclusion of other concomitant lesions should be done. In cases with instability due to the fractured posterior elements, surgical intervention is mandatory. Spine surgeons should be competent to differentiate fracture from the Andersson lesion. In this rare case we highlight also that spine surgeons should obtain intraoperative cultures in cases with Andersson lesions, to exclude the minor possibility of the infectious origin of the entity and/or the possible secondary contamination of the affected area.

Management of Andersson lesions of spine: A systematic review of the existing literature

INTRODUCTION

Andersson lesions also termed as aseptic spondylodiscitis, spinal pseudoarthrosis are known to occur in patients with ankylosing spondylitis. Trauma as well as inflammation has been cited as factors responsible for the causation of these lesions. A variety of surgical approaches have been described in the literature such as anterior, posterior, combined anterior and posterior, with or without reconstruction of the anterior column defect. Controversy still exists regarding the optimal management these lesions.

OBJECTIVE

To address the optimal method of management, levels of instrumentation, requirement of fusion and anterior instrumentation and general epidemiological profile of the patients with Andersson lesions.

MATERIALS AND METHODS

An electronic search for studies on the surgical management of Andersson lesions of spine was performed. Quality assessment of the included articles was done by two independent authors according to the criteria used by researchers previously in systematic reviews.

RESULTS

Males were found to have an increased incidence with the thoracolumbar junction being the most common level. Posterior approach was the most favoured with reconstruction of the gap in the anterior column. Posterior osteotomy with correction of deformity was done commonly for an optimal healing environment. Instrumenting 2-3 levels above and below the lesion is favoured by most.

CONCLUSION

Conservative management for Andersson lesions can be employed in the setting of acute trauma and stable fractures involving a single column. Surgical management of these lesions with a posterior long segment fixation and anterior column reconstruction is the favoured treatment in majority of the cases.

Ankylosing spondylitis complicated with andersson lesion in the lower cervical spine: A case report

BACKGROUND

Andersson lesion (AL) is an uncommon complication in ankylosing spondylitis (AS), which is characterized by nonneoplastic bone destruction and often appears as bone destruction and sclerosis in the vertebral body and/or the area involving the intervertebral disc. According to the literature, Andersson lesion commonly occur in the thoracic and lumbar spine and rarely in the cervical spine.

CASE SUMMARY

This case involved a 78-year-old man with a long history of AS who developed AL in the cervical spine (C5/6 and C6/7). One-stage anterior-posterior approach surgery was successfully performed. At the 6-month follow-up, the pain was significantly reduced, and the limb function was gradually improved.

CONCLUSION

AL uncharacteristically appears in the cervical spine and tends to be misdiagnosed as vertebral metastases or spinal tuberculosis. Posterior combined with anterior surgery achieves solid biological stabilization in the treatment of AL bone destruction.

Pyogenic Andersson Lesion in a Patient With Ankylosing Spondylitis

Although the exact etiology of the Andersson lesion (AL) remains unclear, it is known to occur mostly in patients with long-standing ankylosing spondylitis (AS). Among the various theories for the etiology of AL, repetitive trauma and inflammatory causes are the most common. The histopathological appearance of the AL in this report was consistent with that of chronic inflammation without any infection. Pyogenic ALs in the context of AS are extremely rare; to the best of our knowledge, positive cultures of this lesion in bone biopsies have never been reported. Herein, we report a rare case of a pyogenic AL with a positive culture and discuss a relevant review of the literature.

The contribution of pre-existing spinal pseudarthrosis to the surgical correction for thoracolumbar kyphosis secondary to ankylosing spondylitis

The correction of global kyphosis (GK) for ankylosing spondylitis (AS) patients with pre-existing pseudarthrosis were frequently over 45°. Mismatch between kyphosis correction of GK and pedicle subtraction osteotomy (PSO) may be ascribed to contribution of pseudarthrosis. The aim of the present study was to evaluate surgical outcomes of PSO away from the level of pseudarthrosis and to elucidate the contribution of pre-existing spinal pseudarthrosis in surgical correction of thoracolumbar kyphosis caused by AS. Eighteen AS patients with pre-existing pseudarthrosis were included. PSO outside the level of pseudarthrosis were performed for all the patients. The average follow-up period were 29 months. Radiographs were analyzed for correction and complications. Significant improvement in all sagittal parameters were found postoperatively without obvious correction loss at the final follow-up. Local kyphosis (LK) improved from 23.88° preoperatively to 12.67° postoperatively with a mean correction of 11.47°. Average correction of per PSO segment, GK and sum of disc wedging within fused region (SDW) were 33.53°, 49.27° and 4.00°, respectively. PSO away from the level of pseudarthrosis, but with posterior instrumentation crossing it was a feasible method and was able to maintain sustained surgical outcomes. Regarding GK correction, PSO accounted for 68.1% while pre-existing pseudarthrosis provided 23.3%, which resulted from anterior column opening postoperatively. Thus, extra kyphosis correction attributed to pre-existing pseudarthrosis should be considered for surgical-decision making to prevent overcorrection.