UBE decompression effective treatment option in patients with thoracic OLF

Ossification of the ligamentum flavum (OLF) is an uncommon disease that mostly occurs in East Asians. Laminectomy is often considered when patients develop neuro-related symptoms but may associate with treatment-related complications.

Yue Deng et al conducted a study to evaluate the efficacy and safety of unilateral biportal endoscopic (UBE) decompression treatment in patients with symptomatic OLF.

They found that – the UBE decompression treatment can achieve satisfactory clinical results in patients with thoracic OLF at single level and provide an alternative treatment option. The study has been published in "International Orthopaedics" journal.

Patients with spinal cord compression symptoms and imaging-defined single level thoracic OLF were enrolled in this study and received UBE decompression treatment. Their pre- and postoperative neurological statuses were evaluated by the modified Japanese Orthopaedic Association (mJOA) score, Visual Analog Scale (VAS) for leg pain, and Frankel grade.

Surgical technique:

The skin and the surgical field were prepared and a C-arm fluoroscope was used to locate involved levels. The thinner side of osteophyte was selected for surgical approach. The junction of spinous process and lower laminar margin of superior vertebra was marked and a 1.5-cm skin incision was created both upwards and down wards. Next, the paraspinal muscle was split with serial dilators to enlarge the instrument portal, and the target inter laminar space was located through fluoroscopy.

Surgical method of ipsilateral OLF: The lower edge of the upper lamina was located before removing a part of the lamina with a high-speed drill or laminectomy forceps until the origin of ligamentum flavum and underlying epidural fat were exposed. The adhesions of ventral portion of the OLF were separated with a hooked nerve dissector and the ipsilateral OLF was then removed with laminectomy forceps. After the removal of the ipsilateral OLF, pressure of spinal cord was partially released.

Surgical method of contralateral OLF: The base of spinous process was removed with a highspeed drill or laminectomy forceps to exposure contralateral OLF. The authors introduced two ways for decompression. For mild compression of the spinal cord, they choose osteotome to remove the OLF from the lamina, separate adhesions, and then remove the free OLF. The dural compression was fully relieved. For severe compression, it was not safe to decompress with osteotome. Another method called zero compression was used in such situation. Firstly, the ventral portion of the lamina was removed with a high-speed drill to loosen the OLF. Then laminectomy forceps was used to cut off the marginal junction of OLF to ensure complete dissociation of the OLF. Next, the adhesions were separated and removed the free OLF. The dural sac was exposed, and pulsation of the dural sac was improved. No pressure was applied to the spinal cord during the whole process. The incision was sutured and a drainage tube was placed to drain normal saline into the muscle space for one to two days.

The observations of the study were:

• Fourteen patients (8 male patients and 6 female patients) with an average age of 59.4 years were enrolled in the study.

• The mean operation time was 66.1±15.4 minutes.

• Patients were followed up for at least one year after receiving the treatment.

• The data suggested that the mJOA score (preop 6.2±1.2, 1 year 8.5±0.9; P< 0.001) and VAS score (preop 4.5±2.0, 1 year 0.5±0.9; P< 0.001) were significantly improved compared with that before operation.

• Cerebrospinal fluid leakage occurred in one patient, head and neck pain occurred in two patients, and hyperalgesia of lower limbs occurred in two patients. All these complications did not cause serious consequences.

"Our study suggests that UBE decompression technique with unilateral approach and bilateral decompression is safe and effective for the treatment of thoracic OLF" the authors commented. 

Further reading:

Unilateral biportal endoscopic decompression for symptomatic thoracic ossification of the ligamentum flavum: a case control study.

Yue Deng, Mingzhi Yang et al.

International Orthopaedics (2022) 46:2071–2080

https://doi.org/10.1007/s00264-022-05484-0.