This report involves a 74-year-old male, suffering from metabolic syndrome with insulin-dependent diabetes mellitus type 2, arterial hypertension, obesity (BMI 39 kg/m2), and hypercholesterolemia. Furthermore, the patient has a medical history of pontine stroke, leading to dysarthria and an atactic paresis in the right hand. Relevant spinal history includes a herniated disk on the right at the level of L4-L5 which was successfully treated conservatively with transforaminal epidural infiltrations.
On initial presentation, the primary complaint of the patient was a pain in the right gluteal area with radiation to the right upper leg and impaired walking tolerance. MR imaging showed degenerative discopathies at the L3-L4 and L4-L5 levels:with disc extrusion. On level L4-L5, there is additionally ligamentum flavum hypertrophy resulting in compression of the origin of the L4 root on the right. These findings result in a spinal canal stenosis at both L3-L4 and L4-L5 levels. Electromyographic findings showed a right radiculopathy on level L4. After unsuccessful conservative treatment with epidural infiltrations and exercise therapy, a L4 spinous process resection with laminectomy in combination with a right discectomy L3-L4 was performed (Fig. 1). A facetectomy was not carried out.
After surgery, initial pain control was obtained with alleviation of the sciatica and improved gait performance. However, after a few weeks, the patient presented with a relapse of lumbalgia. This lumbalgia got worse over the following months, with the development of bilateral mechanical sciatica. On clinical examination, there were no signs of motor deficit in the legs, with intact and symmetric knee and Achilles tendon reflexes. At this point, a walking aid was necessary as his walking distance was limited to 100 m. MRI findings showed a hypointense interruption with surrounding bone-marrow edema in the right pedicle of the L4 vertebra (Fig. 2). On electromyography, a L5 radiculopathy was described by new unstable motor units without d enervation activity; this was considered a new finding in comparison with older EMG results. On the left side, a stable multi-level radiculopathy was shown. Epidural infiltrations failed to achieve pain reduction.
Additional Tc99m-HDP-SPECT-CT imaging showed a metabolically active, linear lucency with sclerotic margins in the right pedicle of the L4 vertebra, suggesting a stress fracture (Fig. 3).
Interdisciplinary deliberation with representatives of the different departments incl. neurosurgery, algology, and physical and rehabilitation medicine was scheduled. In retrospect, this pedicular lesion was already apparent on an MRI of the lumbar spine four months after the laminectomy procedure, with bone marrow edema centered around a sclerotic pedicle. A percutaneous posterolateral fusion of L4-L5 was performed.
Due to the COVID-19 pandemic outbreak, postoperative rehabilitation physiotherapy was postponed and started only 3 months after lumbar fusion surgery. Until then, the patient's lumbalgia had significantly improved, but did not resolve completely.