Congenital hypoplasia or aplasia of the lumbosacral pedicle as an unusual cause of spondylolisthesis in the pediatric age group

Case Report: Lumbar spondylolisthesis with unilateral pedicle cleft and contralateral spondylolysis: a report of two cases and literature review

Background

The causes of pedicle cleft include congenital dysplasia and stress fractures, both of which are rare conditions. Secondary lumbar spondylolisthesis with combined unilateral pedicle cleft and contralateral spondylolysis is extremely rare and can be easily misdiagnosed. We report two cases with these conditions from different causes and discuss the diagnostic and therapeutic features in the context of the literature review.

Case description

Case 1 was a 58-year-old female with a stress fracture change at the left L5 pedicle. Case 2 was a 47-year-old female with a pedicle cleft due to hypoplasia of the left L5 pedicle. Both patients had a combined contralateral spondylolysis and Meyerding grade one lumbar spondylolisthesis, while neither had a clear history of lumbar trauma. After initial conservative treatments failed, both patients underwent a single-segment posterior lumbar interbody fusion with bilateral pedicle screw fixation. Both patients were followed up for more than 1 year postoperatively with clinical symptom relief and bony fusion at the pedicle cleft suggested by a CT scan.

Conclusion

Lumbar spondylolisthesis with unilateral pedicle cleft and contralateral spondylolysis is rarely reported and can be clinically misdiagnosed as simple spondylolisthesis with bilateral spondylolysis. There is no widely accepted surgical option for patients for whom conservative treatment has failed. Our experience suggests that good clinical results may be achieved by single-segment posterior interbody fusion and bilateral pedicle screw fixation. Precise screw placement into the deficient pedicle and sufficient exiting nerve decompression are prerequisites for the success of this surgical option.

A biomechanical comparison of posterior fixation approaches in lumbar fusion using computed tomography based lumbosacral spine modelling

Extreme lateral interbody fusion (XLIF) may be performed with a standalone interbody cage, or with the addition of unilateral or bilateral pedicle screws; however, decisions regarding supplemental fixation are predominantly based on clinical indicators. This study examines the impact of posterior supplemental fixation on facet micromotions, cage loads and load-patterns at adjacent levels in a L4-L5 XLIF at early and late fusion stages. CT data from an asymptomatic subject were segmented into anatomical regions and digitally stitched into a surface mesh of the lumbosacral spine (L1-S1). The interbody cage and posterior instrumentation (unilateral and bilateral) were inserted at L4-L5. The volumetric mesh was imported into finite element software for pre-processing, running nonlinear static solves and post-processing. Loads and micromotions at the index-level facets reduced commensurately with the extent of posterior fixation accompanying the XLIF, while load-pattern changes observed at adjacent facets may be anatomically dependent. In flexion at partial fusion, compressive stress on the cage reduced by 54% and 72% in unilateral and bilateral models respectively; in extension the reductions were 58% and 75% compared to standalone XLIF. A similar pattern was observed at full fusion. Unilateral fixation provided similar stability compared to bilateral, however there was a reduction in cage stress-risers with the bilateral instrumentation. No changes were found at adjacent discs. Posterior supplemental fixation alters biomechanics at the index and adjacent levels in a manner that warrants consideration alongside clinical information. Unilateral instrumentation is a more efficient option where the stability requirements and subsidence risk are not excessive.

Congenital agenesis of lumbo-sacral pedicles with associated anomalies: case report with an emphasis on the use of O-arm, navigation in the management with literature review

Background

Congenital spinal pedicle agenesis is rare. The majority of cases are asymptomatic. Few present with either low back pain or radiculopathy. Pedicle screw insertion may pose difficulties in view of abnormal anatomy.

Case presentation

Between Jan 2005 and March 2021, all the data were retrospectively reviewed for the cases operated for congenital anomalies. Three such cases were operated. Case 1 had bilateral agenesis of L5 vertebra with an ectopic kidney in right iliac fossa, absent uterus, absent ovaries and vaginal atresia. Case 2 had absent S1 pedicle with conjoint left L5 nerve root. Case 3 had hypoplastic left L5 pedicle, contained disc herniation, facetal arthropathy. Pedicle screws were placed using O-arm and navigation.

Conclusion

Pedicle agenesis increases the difficulty in pedicle screw fixation and fusion. Anomalous facet and conjoint nerve root need to be looked for intraoperatively. Use of O-arm and CT navigation is of great help in getting safe and accurate anchor points for screw placement avoiding neurological injury.

Lumbo-sacral pedicular aplasia diagnosis and treatment: a systematic literature review and case report

Aplasia of the lumbar pedicle is a rare condition, frequently associated with low back pain. Its recognition is fundamental in the definition of the correct treatment. We performed a literature review in order to clarify how to best diagnose and treat this rare anatomical condition. A comprehensive literature search for studies published through October 2020 was performed, using the following algorithm: "aplasia" OR "aplastic" OR "hypoplasia" OR "hypoplastic" OR "absent" OR absence" AND "pedicle" AND "lumbar" OR "sacral" OR "lumbosacral". References from reviewed papers were further evaluated for the inclusion of other relevant studies. Eighteen studies were included in the systematic review for a total of 24 adult patients. Another case of left L5 pedicle aplasia treated at our hospital has been described and included in the present review. This anatomical condition may be suspected in plain x-Ray, but CT scan 3D reconstructions may help to confirm the diagnosis in equivocal cases. Low-back pain and radiculopathy are the main signs and symptoms. The treatment was described in 14 cases. Eight patients underwent surgical intervention. In cases with spondylolisthesis, fusion surgery was performed with different techniques, obtaining an excellent clinical outcome. Pedicular aplasia is a rare condition that must be recognized in patients with a low back. When it is associated with spondylolisthesis, fusion surgery should be the preferred option.

Surgical management of congenital thoracic kyphosis and multilevel bilateral thoracic pedicle aplasia: case report

Pedicle aplasia is an uncommon congenital anomaly most frequently involving the absence of a single pedicle at a single vertebral level. Bilateral pedicle aplasia at multiple levels is exceedingly rare and has only been described once previously in the literature. While single-level pedicle aplasia is often asymptomatic and discovered incidentally, pedicle aplasia of multiple levels may produce severe spinal deformities and neurological deficits. Due to the rarity of this condition, optimal management remains uncertain. In this case report, the authors describe the surgical management of a healthy 9-year-old boy who presented with frequent falls, difficulty running, and severe thoracic kyphotic deformity and was found to have bilateral pedicle aplasia from T3 to T9. A review of the literature regarding pedicle aplasia is also presented.

Congenital hypoplasia of the lumbar pedicle with spondylolisthesis: report of 2 cases

Congenital hypoplasia of the spinal pedicle is a rare condition. Previously reported cases were treated conservatively or with posterior instrumented fusion. However, the absence or hypoplasia of the lumbar pedicle may increase the difficulty of pedicle screw fixation and fusion. Herein, the authors describe 2 cases of rare adult congenital hypoplasia of the right lumbar pedicles associated with spondylolisthesis. The patients underwent anterior lumbar interbody fusion with a stand-alone cage as well as percutaneous pedicle screw fixation. This method was used to avoid the difficulties associated with pedicle screw fixation and to attain solid fusion. Both patients achieved satisfactory outcomes after a minimum of 2 years of follow-up. This method may be an alternative for patients with congenital hypoplasia of the lumbar spinal pedicle.

Nationwide practice patterns in the use of recombinant human bone morphogenetic protein-2 in pediatric spine surgery as a function of patient-, hospital-, and procedure-related factors

OBJECT

Current national patterns as a function of patient-, hospital-, and procedure-related factors, and complication rates in the use of recombinant human bone morphogenetic protein-2 (rhBMP-2) as an adjunct to the practice of pediatric spine surgery have scarcely been investigated.

METHODS

The authors conducted a cross-sectional study using data from the Healthcare Cost and Utilization Project Kids' Inpatient Database. Univariate and multivariate logistic regression were used to calculate unadjusted and adjusted odds ratios and 95% confidence intervals, and p values < 0.05 were considered to be statistically significant.

RESULTS

The authors identified 9538 hospitalizations in pediatric patients 20 years old or younger who had undergone spinal fusion in the US in 2009; 1541 of these admissions were associated with rhBMP-2 use. By multivariate logistic regression, the following factors were associated with rhBMP-2 use: patient age 15-20 years; length of hospital stay (adjusted odds ratio [aOR] 1.01, p = 0.017); insurance status (private [aOR 1.49, p < 0.001] compared with Medicaid); hospital type (nonchildren's hospital); region (Midwest [aOR 2.49, p = 0.008] compared with Northeast); spinal refusion (aOR 2.20, p < 0.001); spinal fusion approach/segment (anterior lumbar [aOR 1.73, p < 0.001] and occipitocervical [aOR 1.86, p = 0.013] compared with posterior lumbar); short segment length (aOR 1.42, p = 0.016) and midlength (aOR 1.44, p = 0.005) compared with long; and preoperative diagnosis (Scheuermann kyphosis [aOR 1.56, p < 0.017] and spondylolisthesis [aOR 1.93, p < 0.001]).

CONCLUSIONS

Use of BMP in pediatric spine procedures now comprises more than 10% of pediatric spinal fusion. Patient-related (age, insurance type, diagnosis); hospital-related (children's hospital vs general hospital, region in the US); and procedure-related (redo fusion, anterior vs posterior approach, spinal levels, number of levels fused) factors are associated with the variation in BMP use in the US.