Avulsion and Intraspinal Herniation of the Multifidus Muscle Causing Cauda Equina Syndrome: A Rare Case Report
Jie Liu1,2,3, Xin Shi1,2,3, Yachen Li4,2,3
1Department of Orthopaedics, The First People's Hospital of Yunnan Province.The Affiliated Hospital of Kunming University of Science and Technology, Kunming, Yunnan, China.
Background:
Multifidus muscle tears are uncommon injuries, and herniation of muscle tissue into the spinal canal has not been previously reported. This report presents a rare case of traumatic multifidus muscle herniation into the spinal canal, leading to cauda equina syndrome. The primary research question is whether a specific sequential injury mechanism can explain this unusual pattern of intraspinal muscle herniation.
Methods:
An 18-year-old woman presented with back pain, bilateral lower limb and perineal numbness, lower extremity weakness, and urinary retention after a fall from height. Magnetic resonance imaging demonstrated an intraspinal soft tissue mass at the L2 level causing thecal sac compression, consistent with cauda equina syndrome. The patient underwent urgent decompressive laminectomy with pedicle screw fixation from T12 to L3 and underwent posterolateral bone graft fusion at L1 to L2. Intraoperative findings and histopathological examination confirmed the nature of the compressive mass.
Results:
Preoperative imaging, intraoperative visualization, and postoperative pathology confirmed that the intraspinal mass represented herniated multifidus muscle tissue. At 6-month follow-up, the patient demonstrated complete neurological recovery without residual symptoms. The proposed mechanism involves sequential hyperflexion and hyperextension forces during the traumatic event, potentially creating a transient osseous gap allowing muscle herniation.
Conclusions:
This rare case demonstrates that traumatic hyperflexion-hyperextension injury can result in intraspinal herniation of the multifidus muscle, leading to cauda equina syndrome. Recognition of this potential mechanism may aid in diagnosis and timely surgical intervention.
Clinical Relevance:
Clinicians should consider soft tissue herniation, including muscle, in the differential diagnosis of traumatic intraspinal masses causing neurological compromise. Prompt surgical decompression can achieve excellent neurological outcomes.
