Management of Pseudarthrosis at Transitional Vertebra L5
In an asymptomatic patient with incidental pseudarthrosis at a transitional L5 vertebra, no treatment is indicated—observation is appropriate. However, if symptoms develop (axial back pain, radiculopathy, or functional limitations), surgical revision with instrumented fusion should be considered.
Clinical Significance and Initial Assessment
The critical first step is determining whether this pseudarthrosis is symptomatic:
Asymptomatic pseudarthrosis does not require intervention 1. Many patients with radiographic evidence of pseudarthrosis remain pain-free and functional during daily activities 2.
Symptomatic pseudarthrosis typically manifests as persistent or recurrent axial pain, radiculopathy, or functional disability months to years after attempted fusion 3, 1.
In one study of vertebral pseudarthrosis, 95% of conservatively managed patients experienced pain reduction over time, and 91% did not complain of intolerable pain despite persistent radiographic instability 2.
Diagnostic Confirmation
If symptoms are present, confirm the pseudarthrosis is the pain source:
CT imaging with fine-cut axial and multiplanar reconstruction is the recommended modality for assessing fusion status at the lumbosacral junction 4.
Flexion-extension radiographs can demonstrate motion at the pseudarthrosis site, though the degree of motion indicative of failed fusion remains controversial 1.
Rule out other causes of pain before attributing symptoms to pseudarthrosis 1.
The absence of bilateral facet fusion on CT is more suggestive of true nonunion than absence of posterolateral fusion 4.
Treatment Algorithm for Symptomatic Cases
Conservative Management First
Initial conservative treatment for approximately 4 months is recommended before considering surgical intervention 2.
This approach is justified because many patients experience spontaneous pain improvement despite persistent radiographic instability 2.
Surgical Intervention Indications
Proceed with revision surgery if:
- Persistent severe pain after 4 months of conservative management 2
- Progressive neurological deficits 2
- Documented symptomatic pseudarthrosis with functional impairment 3
Surgical Approach
Revision fusion with rigid instrumentation is recommended for symptomatic lumbar pseudarthrosis:
Success rates are enhanced with rigid instrumentation compared to non-instrumented techniques 5.
The revision should include replacement of any loose instrumentation, use of biologics, and consideration of interbody fusion techniques 5.
For lumbosacral pseudarthrosis, extending fixation to include adequate proximal and distal anchoring points is essential 5.
Adjunctive Therapies (Limited Evidence)
Pulsed electromagnetic field stimulation (PEMFS) may be considered as a non-invasive option:
One case series showed 67% fusion success rate with PEMFS treatment for at least 90 days in established pseudarthrosis 4.
However, this represents only Level IV evidence, and PEMFS should be viewed as complementary rather than a substitute for surgical revision in symptomatic cases 4.
Direct current stimulation (DCS) is not recommended, as Level II evidence shows no impact on fusion rates 4.
Important Clinical Caveats
Transitional vertebrae present unique anatomical considerations that may affect surgical planning, including altered biomechanics and potential for asymmetric fusion 1.
The correlation between radiographic pseudarthrosis and clinical symptoms is imperfect—some patients with clear radiographic nonunion remain asymptomatic 2, 1.
Metabolic factors, smoking status, and bone quality significantly influence revision fusion success rates and should be optimized preoperatively 1.
Given the incidental nature of this finding with no acute abnormalities noted, observation is the most appropriate initial management unless the patient develops symptoms attributable to the pseudarthrosis.