Nerve root anomalies: making sense of a complicated literature

Nerve root anomaly as a cause of unexpected outcomes of epidural steroid injections in lumbar radiculopathy: A case report

BACKGROUND

Spinal nerve root anomaly is a rare feature that can result in unexpected outcomes in epidural steroid injections or surgical procedures. Preoperative diagnostic tools for root anomalies are limited, as they are usually found intraoperatively.

OBJECTIVE

This case report aims to propose an effective diagnostic process for nerve root anomalies by introducing clinical manifestations, electrodiagnostic findings, and sophisticated imaging techniques such as coronal view magnetic resonance imaging (MRI) of the lumbosacral spine.

CASE DESCRIPTION

A 43-year-old female complained of low back pain with radicular pain to the lower extremities. Based on physical examination, electrodiagnosis, and imaging studies, right L5 radiculopathy was diagnosed. Repetitive image-guided epidural steroid injections presented unsuccessful outcomes. She was then referred to a neurosurgeon for surgical decompression, which resulted in significant improvement in her radicular pain. A nerve root anomaly was found intraoperatively, and the coronal images of postoperative MRI depicted the conjoined nerve root of the lumbar spine.

CONCLUSION

When proper image-guided spinal interventions for discogenic radicular pain are not effective, a clinician should be advised to consider the possibility of anatomical variation, including nerve root anomalies. Early diagnosis of nerve root anomalies by utilizing multiple diagnostic tools, especially coronal MRI, can aid in preoperative diagnosis and proper clinical decisions for symptom management.

Microendoscopic decompression of conjoined lumbosacral nerve roots

Nerve root morphological variability is often incompletely appreciated on preoperative imaging and can complicate intraoperative decision-making. This case demonstrates the utility of spinal endoscopy in the visualisation and manipulation of conjoined nerve roots and includes procedural images to promote better understanding and awareness of this anatomical anomaly. A woman in her 50s presented with 1 year of progressive left S1 radiculopathy refractory to non-operative modalities. History and examination were notable for S1 dermatomal paresthesias, positive ipsilateral straight leg raise and grade 4/5 gastrocnemius strength. MRI demonstrated an L5-S1 left paracentral disc herniation causing severe lateral recess stenosis. Endoscopic decompression revealed conjoined lumbosacral nerve roots. Laminotomies and discectomy provided circumferential decompression. The patient experienced immediate and sustained relief of her preoperative radiculopathy as manifested in patient-reported outcome measures. Evolving endoscopic spine platforms provide novel visualisation of nerve root anomalies yielding new insight on safe and effective decompressive techniques.

Clinical and radiological outcomes in patients who underwent posterior lumbar interbody fusion: comparisons between unilateral and bilateral cage insertion

BACKGROUND

Although the original technique involves inserting two cages bilaterally, there could be situations that only allow for insertion of one cage unilaterally. However, only a few studies have compared the outcomes between unilateral and bilateral cage insertion. The purpose of this study was to compare the clinical and radiological outcomes in patients who underwent posterior lumbar interbody fusion (PLIF) between unilaterally and bilaterally inserted cages.

METHODS

Among 206 eligible patients who underwent 1- or 2-level PLIF, 78 patients were 1:3 cohort-matched by age, sex, and operation level (group U, 19 patients with unilateral cages; and group B, 57 patients with bilateral cages). Fusion status was evaluated by computed tomography (CT) scans at postoperative 1 year. Clinical outcomes were measured by visual analog scale (VAS), Oswestry Disability Index (ODI), and EQ-5D. Radiological and clinical parameters were compared between the two groups. Risk factors for pseudarthrosis were also analyzed by multivariate analysis.

RESULTS

The demographic data were not significantly different between the two groups. However, previous laminectomy, asymmetric disc collapse, and fusion at L5-S1 level were more frequently found in group U (P = 0.003, P = 0.014, and P = 0.014, respectively). Furthermore, pseudarthrosis was more frequently observed in group U (36.8%) than in group B (7.0%) (P = 0.004). Back pain VAS was higher in group U at postoperative 1 year (P = 0.033). Lower general activity function of EQ-5D was observed in group U at postoperative 1 year (P = 0.035). Older age (P = 0.028), unilateral cage (P = 0.007), and higher bone mineral density (P = 0.033) were positively correlated with pseudarthrosis.

CONCLUSIONS

Unilaterally inserted cage might be a possible risk factor for pseudarthrosis when performing PLIF, which could be related with the difficult working conditions such as scars due to previous laminectomy or asymmetric disc collapse. Furthermore, suboptimal clinical outcomes are expected following PLIF with unilateral cage insertion at postoperative 1 year regardless of similar clinical outcomes at postoperative 2 year. Therefore, caution is advised when inserting cages unilaterally, especially under above-mentioned conditions in terms of its possible relationship with symptomatic pseudarthrosis.

Extradural and intradural characteristics of the cervical nerve root anomalies

The anomalous anatomical arrangement of the cervical spinal nerve roots within the spinal canal can complicate the surgical treatment of several pathologies. This work aimed to reveal intraspinal anatomical anomalies of the extradural and also intradural cervical spinal nerve roots courses. The anatomical study was realised in 43 cadavers with a mean age of 53.7 (32 men and 11 women). After opening the spinal canal and also the dural sac the intradural and extradural anomalies of the cervical spinal nerve roots (bilaterally) were explored and documented. We found completely 49 cases (56.98%) of intraspinal cervical nerve root anomalies. Extradural anomalies were found in 11 cases (12.79%) including atypical spacing, two roots exiting through one neuroforamen, extradural communications, aberrant root. Intradural anomalies observed in 28 cases (32.56%) comprised: communications between the dorsal roots and ventral roots separately or together and the multiple communications. Other anomalies (10 cases, 11.63%) included various types of atypical spacing of the roots and their asymmetry. All the results are differentiated according to the plexus type (pre-, postfixed, normotyped). This study describes intraspinal (extradural and intradural) anatomical anomalies of the cervical spinal nerve root courses. Knowledge of these variabilities should help to prevent the failure of several medical procedures.