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Open access

Internal iliac artery aneurysm masquerading as a sciatic nerve schwannoma: illustrative case

Lokeshwar S. Bhenderu, Khaled M. Taghlabi, Taimur Hassan, Jaime R. Guerrero, Jesus G. Cruz-Garza, Rachel L. Goldstein, Shashank Sharma, Linda V. Le, Tue A. Dinh, and Amir H. Faraji

BACKGROUND

Schwannomas are common peripheral nerve sheath tumors. Imaging techniques such as magnetic resonance imaging (MRI) and computed tomography (CT) can help to distinguish schwannomas from other types of lesions. However, there have been several reported cases describing the misdiagnosis of aneurysms as schwannomas.

OBSERVATIONS

A 70-year-old male with ongoing pain despite spinal fusion surgery underwent MRI. A lesion was noted along the left sciatic nerve, which was believed to be a sciatic nerve schwannoma. During the surgery for planned neurolysis and tumor resection, the lesion was noted to be pulsatile. Electromyography mapping and intraoperative ultrasound confirmed vascular pulsations and turbulent flow within the aneurysm, so the surgery was aborted. A formal CT angiogram revealed the lesion to be an internal iliac artery (IIA) branch aneurysm. The patient underwent coil embolization with complete obliteration of the aneurysm.

LESSONS

The authors report the first case of an IIA aneurysm misdiagnosed as a sciatic nerve schwannoma. Surgeons should be aware of this potential misdiagnosis and potentially use other imaging modalities to confirm the lesion before proceeding with surgery.

Open access

Surgical treatment of sural nerve entrapment aided by imaging- and electrography-based diagnosis: illustrative case

Maoki Matsubara, Kenji Yagi, Shoji Hemmi, and Masaaki Uno

BACKGROUND

The sural nerve (SN) is a cutaneous sensory nerve that innervates the posterolateral side of the distal third of the leg and lateral side of the foot. The SN has wide variation in its course and is fixed to the subcutaneous tissue and superficial fascia. Idiopathic spontaneous SN neuropathy is rarely surgically treated because of the difficulty in detecting SN entrapment.

OBSERVATIONS

Herein, the authors present a rare case of surgically treated spontaneous SN neuropathy. A 67-year-old male patient presented with right foot pain for several years. Magnetic resonance imaging and ultrasonography showed SN entrapment slightly proximal and posterior to the lateral malleolus. A nerve conduction study showed SN disturbance. After undergoing neurolysis, the patient’s foot pain was alleviated.

LESSONS

Idiopathic SN neuropathy can be treated surgically when SN entrapment is detected with comprehensive evaluation methods.

Open access

Etiology of spastic foot drop among 16 patients undergoing electrodiagnostic studies: patient series

Lisa B. E. Shields, Vasudeva G. Iyer, Yi Ping Zhang, and Christopher B. Shields

BACKGROUND

Differentiating foot drop due to upper motor neuron (UMN) lesions from that due to lower motor neuron lesions is crucial to avoid unnecessary surgery or surgery at the wrong location. Electrodiagnostic (EDX) studies are useful in evaluating patients with spastic foot drop (SFD).

OBSERVATIONS

Among 16 patients with SFD, the cause was cervical myelopathy in 5 patients (31%), cerebrovascular accident in 3 (18%), hereditary spastic paraplegia in 2 (12%), multiple sclerosis in 2 (12%), chronic cerebral small vessel disease in 2 (12%), intracranial meningioma in 1 (6%), and diffuse brain injury in 1 (6%). Twelve patients (75%) had weakness of a single leg, whereas 2 others (12%) had bilateral weakness. Eleven patients (69%) had difficulty walking. The deep tendon reflexes of the legs were hyperactive in 15 patients (94%), with an extensor plantar response in 9 patients (56%). Twelve patients (75%) had normal motor and sensory conduction, 11 of whom had no denervation changes of the legs.

LESSONS

This study is intended to raise awareness among surgeons about the clinical features of SFD. EDX studies are valuable in ruling out peripheral causes of foot drop, which encourages diagnostic investigation into a UMN source for the foot drop.

Open access

Radial nerve myofibroma: a rare benign tumor with perineural infiltration. Illustrative case

Kitty Y. Wu, David J. Cook, Kimberly K. Amrami, and Robert J. Spinner

BACKGROUND

Myofibromas are benign mesenchymal tumors, classically presenting in infants and young children in the head and neck region. Perineural involvement, especially in peripheral nerves within the upper extremity, is extremely rare in myofibromas.

OBSERVATIONS

The authors present the case of a 16-year-old male with a 4-month history of an enlarging forearm mass and rapidly progressive dense motor weakness in wrist, finger, and thumb extension. Preoperative imaging and fine needle biopsy confirmed the diagnosis of a benign isolated myofibroma. Given the dense paralysis, operative management was indicated, and intraoperative exploration showed extensive involvement of tumor within the radial nerve. The infiltrated nerve segment was excised along with the tumor, and the resulting 5-cm nerve gap was reconstructed using autologous cabled grafts.

LESSONS

Perineural pseudoinvasion can be an extremely rare and atypical feature of nonmalignancies, resulting in dense motor weakness. Extensive nerve involvement may still necessitate nerve resection and reconstruction, despite the benign etiology of the lesion.

Open access

Iatrogenic contralateral foraminal stenosis following lumbar spine fusion surgery: illustrative cases

Faisal Konbaz, Sahar Aldakhil, Fahad Alhelal, Majed Abalkhail, Anouar Bourghli, Khawlah Ateeq, and Sami Aleissa

BACKGROUND

Lumbar spine fusion is the mainstay treatment for degenerative spine disease. Multiple potential complications of spinal fusion have been found. Acute contralateral radiculopathy postoperatively has been reported in previous literature, with unclear underlying pathology. Few articles reported the incidence of contralateral iatrogenic foraminal stenosis after lumbar fusion surgery. The aim of current article is to explore the possible causes and prevention of this complication.

OBSERVATIONS

The authors present 4 cases in which patients developed acute postoperative contralateral radiculopathy requiring revision surgery. In addition, we present a fourth case in which preventive measures have been applied. The aim of this article was to explore the possible causes and prevention to this complication.

LESSONS

Iatrogenic foraminal stenosis of the lumbar spine is a common complication; preoperative evaluation and middle intervertebral cage positioning are needed to prevent this complication.

Open access

Iatrogenic median and ulnar nerve injuries during carpal tunnel release: clinical, electrodiagnostic, and ultrasound features in 12 patients. Patient series

Lisa B. E. Shields, Vasudeva G. Iyer, Yi Ping Zhang, and Christopher B. Shields

BACKGROUND

Nerve injuries during carpal tunnel release (CTR) are rare. Electrodiagnostic (EDX) and ultrasound (US) studies may be helpful in evaluating iatrogenic nerve injuries during CTR.

OBSERVATIONS

Nine patients sustained a median nerve injury, and 3 patients experienced ulnar nerve damage. Decreased sensation occurred in 11 patients, and dysesthesia occurred in 1 patient. Abductor pollicis brevis (APB) weakness occurred in all patients with median nerve injury. Of the 9 patients with median nerve injury, the compound muscle action potentials (CMAPs) of the APB and sensory nerve action potentials (SNAPs) of the 2nd or 3rd digit were not recordable in 6 and 5 patients, respectively. Of the 3 patients sustaining ulnar nerve injuries, the CMAPs of the abductor digiti minimi (ADM) and SNAPs of the 5th digit were not recordable in 1 patient; 2 patients showed prolonged latency and decreased amplitude of CMAPs/SNAPs. US studies of 8 patients with a median nerve injury showed a neuroma within the carpal tunnel. One patient underwent surgical repair urgently, and 6 did so after variable intervals.

LESSONS

Surgeons should be cognizant of nerve injuries during CTR. EDX and US studies are useful in evaluating iatrogenic nerve injuries during CTR.

Open access

Peroneal intraneural ganglion cyst with a nearly invisible joint connection (even to advocates of the articular theory): illustrative case

Karina A. Lenartowicz, Kimberly K. Amrami, and Robert J. Spinner

BACKGROUND

The articular (synovial) theory describes the formation of intraneural ganglion cysts through defects in the capsule of synovial joints. While the articular theory is gaining significant traction in the literature, it is not universally accepted. Therefore, the authors present a case of a plainly visible peroneal intraneural cyst, although the subtle joint connection was not identified specifically at the time of surgery, with subsequent rapid extraneural cyst recurrence. The joint connection was not immediately evident on review of the magnetic resonance imaging, even to the authors who have a large experience with this clinical entity. The authors report this case to demonstrate that all intraneural ganglion cysts have joint connections, although they may be difficult to identify.

OBSERVATIONS

An occult joint connection in the intraneural ganglion poses a unique diagnostic and management dilemma. High-resolution imaging is a valuable tool used to identify the articular branch joint connection as part of the surgical planning.

LESSONS

Based on the articular theory, all intraneural ganglion cysts will have a joint connection through an articular branch, although this may be small or nearly invisible. Failure to appreciate this connection can lead to cyst recurrence. A high index of suspicion of the articular branch is needed for surgical planning.

Open access

Occult lipomatosis of the nerve as part of macrodystrophia lipomatosa: illustrative case

Tomas Marek, Kimberly K. Amrami, and Robert J. Spinner

BACKGROUND

Macrodystrophia lipomatosa (MDL) is characterized by progressive overgrowth affecting soft tissues and bony structures and is part of lipomatous overgrowth syndromes. MDL has been associated with lipomatosis of the nerve (LN), an adipose lesion of nerve that has a pathognomonic magnetic resonance imaging (MRI) appearance as well as a mutation in the PIK3CA gene. The authors present a case of occult LN in the setting of MDL.

OBSERVATIONS

A 2-year-old boy with progressive soft tissue overgrowth of his proximal right lower extremity was initially diagnosed with neurofibromatosis type 1 (NF1). At our institution, NF1 as well as other overgrowth syndromes including PTEN hamartoma tumor syndrome were excluded. He was diagnosed as having so-called MDL. Upon reinterpretation of the patient’s MRI studies, short-segment LN involving the proximal sciatic nerve and part of lumbosacral plexus was identified. He underwent 2 debulking/liposuction procedures for soft tissue overgrowth. Genetic testing of tissue revealed a mutation in PIK3CA.

LESSONS

Thorough clinical examination (for signs of overgrowth) as well as an MRI study of the entire neural pathway is a critical part of the diagnostic workup to evaluate for LN. The authors believe that an increasing association of LN, even when occult, will emerge that will explain many cases with marked nerve-territory overgrowth.

Open access

Anesthesia-induced Takotsubo cardiomyopathy in trigeminal neuralgia: illustrative case

Guido Mazzaglia, Giulio Bonomo, Emanuele Rubiu, Paolo Murabito, Alessia Amato, Paolo Ferroli, and Marco Gemma

BACKGROUND

Takotsubo syndrome (TS) represents a form of nonischemic cardiomyopathy characterized by sudden and temporary weakening of the myocardium. Many data suggest a primary role for sympathetic overstimulation in its pathogenesis. Nevertheless, these correlates are less easily identified during anesthesia.

OBSERVATIONS

A 50-year-old female patient with a 4-year history of drug-resistant left trigeminal neuralgia. She was scheduled for surgical microvascular decompression. In the operating room, after induction of general anesthesia and oral intubation, the electrocardiogram revealed a significant ST segment elevation along with a sudden decrease in systolic blood pressure and heart rate. Administration of atropine caused a conversion into ventricular tachycardia. The advanced cardiac life support protocols were applied with prompt defibrillation and rapid recovery at sinus rhythm. A transthoracic echocardiogram revealed apical akinesia with ballooning of the left ventricle with a reduction of systolic function. An emergency coronary arteriography was performed, showing normal epicardial coronary vessels. After 4 days, echocardiography revealed normalization of the left ventricular function with improvement of the ejection fraction.

LESSONS

In patients affected by trigeminal neuralgia, chronic pain can lead to a state of adrenergic hyperactivation, which can promote TS during the induction of general anesthesia, probably through the trigeminocardiac reflex.

Open access

Delayed motor weakness following peripheral nerve schwannoma resection: illustrative cases

Rohin Singh and Robert J. Spinner

BACKGROUND

Delayed facial palsy (DFP) after vestibular schwannoma resection is a well-documented, yet poorly understood condition. The exact pathophysiological mechanisms of DFP are unknown, although diminished intraoperative nerve response has been shown to be a prognostic factor. To date, no such condition has been described in regard to peripheral nerve schwannomas.

OBSERVATIONS

Here the authors present the first reported cases of delayed motor weakness (DMW) after peripheral schwannoma resection of the ulnar nerve at the elbow and peroneal nerve in the popliteal fossa. Both patients presented with a mass lesion and radiating paresthesias and had normal motor function preoperatively. Immediately after surgical resection, the patients had full strength. Within 24 hours, both patients exhibited marked weakness that gradually resolved over the course of several weeks.

LESSONS

DMW after peripheral schwannoma resection is a rare condition likely akin to delayed facial nerve palsy after VS resection. The mechanism of this phenomenon remains unknown, although symptoms appear to self-resolve with time. A better understanding of the processes driving this condition may allow for therapies that can expedite and improve long-term outcomes.