Posterior interosseous nerve syndrome caused by a ganglion cyst and its surgical release with intraoperative neurophysiological monitoring

Abstract

Rationale: Intraoperative neurophysiological monitoring (IONM) has been utilized not only for the rapid detection of neural insults during surgeries, but also to verify the neurophysiological integrity of nerve lesions in the surgical field. Patient concerns: A 32-year-old woman presented with a wrist and finger drop that had lasted about 3 months. Diagnoses: The result of the initial electrodiagnostic test was consistent with posterior interosseous nerve (PIN) syndrome. Ultrasonography and magnetic resonance imaging of the proximal forearm showed a cystic mass at the anterolateral aspect of the radial head, which was diagnosed as a ganglion cyst. Interventions: Surgical release of the ganglion cyst with IONM was performed. During the surgery, we induced nerve action potentials and compound motor action potentials across the ganglion cyst, which demonstrated neural continuity. Outcomes: Three months after the surgery, the patient showed partial recovery of wrist and finger extensor muscle power. An electrodiagnostic test conducted 3 months after the surgery showed reinnervation potentials in PIN-innervated muscles. Lessons: IONM during peripheral nerve surgeries can support surgical decisions and confirm the location and degree of nerve damage.

Imaging characteristics of posterior interosseous nerve syndrome

“…Another useful tool besides ultrasonography for diagnosing neuropathy is electromyography, which helps localize the lesion and rule out brachial plexus injury [3] . The manifestation of PINs on electromyography is a reduced or blockage of motor nerve conduction at the injured site, a decrease in the response amplitude of the extensor digitorum muscle, and in addition, spontaneous potentials may appear in the extensor digitorum muscle; sensory conduction is still preserved [3 , 14] . In cases of PINs, anatomical variations that cause nerve compression are often difficult to visualize by MRI, however, MRI is sensitive in detecting muscle edema, muscle atrophy, and fatty infiltration [4] .…”

Removal of schwannoma from the psoas muscle with intraoperative neurophysiological monitoring: A case report

“…Kravtsov et al [ 10 ] reported a case of neurinoma of the fifth lumbar nerve root that was surgically removed using endoscopy along with IONM; although motor weakness of the great toe extensor persisted, the patient’s pain of the L5 dermatome, which was present prior to the surgery, improved from a visual analog scale score of 7 to 2. In another case involving the surgical release of a ganglion cyst that was compressing the posterior interosseous nerve, resulting in symptoms of wrist and finger drop before the surgery, which was performed under IONM [ 11 ] ; partial recovery of wrist and finger extensor power was observed after the surgery. Patel et al [ 12 ] demonstrated that IONM could minimize the minor and major neural injuries during revision shoulder arthroplasty surgeries.…”

Application of Intraoperative Electromyography Intelligent Monitoring in Orthopedic Surgery under General Anesthesia

“…Although IONM is good for monitoring underlying nerve damage, the efficacy of IONM-induced potential changes has been inconsistent. For example, SEP has been shown to be effective in monitoring spinal cord function during cervical and thoracic spine surgery, but not for nerve root levels during lumbosacral surgery [ 13 ]. SEP can also be used to evaluate specific nerve roots, but it cannot detect immediate changes in iatrogenic injury.…”