• an asian man is experiencing Acute Leg Weakness from Lumbar Disc Degeneration and Facet Joint Inflammation

Clinical Case Study: Acute Leg Weakness from Lumbar Disc Degeneration and Facet Joint Inflammation

August 24, 2026

CONTENTS

shoulder pain specialist singapore

Written by Dr Bernard Lee Mun Kam,
Founder & Consultant Pain Specialist, Singapore Paincare Center
MBBS (NUS) · M Med (Anaesthesiology) (NUS) · FFPMANZCA (ANZCA)

Last updated: 24 August 2026

Presenting Complaint:

A patient in his mid-50s presented with an acute episode of right lower-limb numbness and weakness. The episode began abruptly while at rest: he attempted to stand and found his right leg completely unable to bear weight, with a sensation similar to an electric shock, followed by profuse sweating.

In the preceding weeks, he had experienced a minor, non-painful strain in his lower back following a period of physical exertion, which he treated at home with topical liniment and a medicated plaster. He initially attributed the leg numbness to poor sitting posture, but the weakness did not resolve with repositioning.

For the first several nights after onset, he could only sleep in a seated position, as any change in posture caused a jarring, disruptive sensation in the affected leg. He was unable to work or continue his usual recreational activities during this period.

Prior to specialist review, he was assessed at a walk-in clinic, prescribed oral medication, and advised that hospital-based treatment would be needed if there was no improvement within a week. He also trialled a course of acupuncture, which produced only short-lived relief — improved sensation lasting under five minutes of walking before the numbness and heaviness returned.

Diagnostic Findings

He was referred for magnetic resonance imaging (MRI) of the lumbar spine.

In my review of the MRI, I found that the intervertebral disc between the L3 and L4 vertebrae was degenerated — the disc appeared darkened on the scan, a signal change consistent with dehydration and cartilage breakdown. The adjacent facet joints, the small joints at the back of the spine, showed mild swelling. Encouragingly, I found no evidence of nerve root compression on this scan.

This distinction mattered to my choice of treatment: because the nerve itself was not compressed, decompressive spine surgery, which is usually reserved for cases with confirmed nerve impingement, was not indicated here. Instead, I judged that the acute leg weakness and numbness stemmed from inflammation around the affected facet joint and disc, and that this could be addressed with a targeted, minimally invasive approach rather than open surgery.

Treatment Approach

  1. I administered the procedure with the patient under sedation (a twilight anaesthesia), so that he remained comfortable and unaware of the process throughout.
  2. Using an image-guided laser device, I directed treatment to the swollen portion of the affected facet joint, applying targeted thermal energy to reduce the swelling.
  3. I then applied the same laser technique to the inflamed cartilage of the L3/L4 disc.
  4. The full procedure took approximately 90 minutes.
  5. Following treatment, I arranged a structured recovery plan: several sessions of physiotherapy, and a three-month course of oral medication to relax the affected nerve root and support recovery.
  6. I scheduled follow-up review at three-month intervals to monitor progress.

Outcome

The patient was discharged on the same day as the procedure, though he required a wheelchair for mobility on the evening of treatment. By the following day, he was able to walk unaided to his follow-up appointment at the clinic.

Over the following weeks, his right leg numbness and weakness resolved. He resumed swimming and brisk walking, and later took part in hill walking. He returned to full-time work without restriction and resumed his previous recreational activities, including multi-day boat trips. At his most recent quarterly follow-up, his condition remained stable.

This outcome reflects one individual case. Treatment suitability and results depend on each patient’s specific diagnosis and clinical assessment.

Ask the Doctor

Q: Why did my leg suddenly go numb and weak, and why wasn’t I offered surgery straight away?

A: Sudden leg numbness like this is often assumed to mean a nerve is being pinched by a slipped disc, and in many cases surgery is the right answer. But when I reviewed this patient’s MRI, I found that although his L3/L4 disc had degenerated and the nearby facet joint was swollen, the nerve itself was not compressed. Because there was no nerve compression, I was able to treat the inflamed joint and disc directly with a minimally invasive, image-guided laser technique rather than open surgery, which meant a same-day discharge and a much shorter recovery.

— Dr Bernard Lee Mun Kam, Pain Specialist