The Utility of Ultrasound in the Assessment of Traumatic Peripheral Nerve Lesions: Report of 4 Cases

Joshua Zeidenberg, MD; S. Shelby Burks, MD; Jean Jose, DO; Ty K. Subhawong, MD; Allan D. Levi, MD, PhD

Disclosures

Neurosurg Focus. 2015;39(3):e3 

In This Article

Case Reports

Case 1

A 16-year-old boy presented to our neurosurgery clinic 1 month after sustaining a lacerating injury to his left thigh at the superior border of the popliteal fossa. At the initial presentation, primary repair of the tibial nerve was attempted, and the leg was splinted at 45° of flexion. In the clinic, he complained of severe pain in the distribution of the sciatic nerve, and physical examination showed Grade 0/5 strength of ankle dorsiflexion, eversion, plantar flexion, and extensor hallucis longus. There was absent sensation on the lateral leg and both surfaces of the foot. EMG studies revealed a lack of distal reinnervation in leg musculature for both tibial and peroneal distributions. MRI revealed evidence of a laceration of the tibial and common peroneal nerves resulting in complete transection (Fig. 1). Diagnostic ultrasound performed on the same date showed complete transection of these nerves at the level of the popliteal fossa and early formation of end-bulb neuromas (Fig. 2). The tibial graft had likely failed as a result of tension between the 2 nerve endings. These findings were confirmed intraoperatively (Fig. 3). The patient underwent neuroma resection and end-to-end grafting with 6 autologous sural nerve grafts applied to the tibial nerve, each spanning 4 cm, and 4 similar grafts, 6 cm in length, were applied to the peroneal nerve.

Figure 1.

Coronal T2 SPACE (sampling perfection with application optimized contrasts using different flip angle evolution) sequences through the level of the knee revealing laceration of the tibial and common peroneal nerves. There is a gap between the ends of the lacerated tibial nerve (short arrows) and lacerated common peroneal nerve (long arrows).

Figure 2.

A: HRU image of the tibial nerve reveals scar tissue at the level of transection (arrows) measuring 3 cm, inclusive of end-bulb neuroma formation at the proximal and distal stump margins B: Similarly, the gap between the transected ends of the common peroneal nerve is 3 cm (calipers).

Figure 3.

Intraoperative Image of tibial (Inferior) and peroneal (superior) nerves at their bifurcation from the sciatic nerve and their course dis-tally. The lateral head of the gastrocnemius splits the 2 nerves as they travel to the leg. The lacerating injury to both nerves is apparent in the significant gaps. In addition, enlargement of the distal stumps can be seen. This neuromatous enlargement appears most prominent in the tibial branch.

Case 2

A 74-year-old man presented to the neurosurgery clinic 3 months after undergoing a percutaneous femoral artery approach for a cardiac ablation procedure. The patient reported experiencing immediate left proximal leg weakness after the procedure and numbness along the medial leg. On physical examination of the left lower extremity, he had Grade 3/5 strength on hip flexion and Grade 1/5 strength on knee extension. He had diminished sensation along the saphenous nerve distribution. MRI showed a heterogeneous mass arising off the left profunda femoral artery that appeared to abut and dissect into the adjacent femoral nerve, which itself showed signal abnormality (Fig. 4). Ultrasound performed on the same day showed a pseudoaneurysm dissecting and displacing the left femoral nerve (Fig. 5). The patient underwent surgery for vascular repair and neurolysis of the left femoral nerve with sural nerve grafting (Fig. 6). The patient showed clinical improvement of his symptoms with improved correlative EMG findings 3 months after surgery.

Figure 4.

Coronal T2-weighted image of the pelvis shows a heterogeneous signal intensity mass abutting and dissecting into the left femoral nerve (arrow). The central enhancement and peripheral signal void represent the to-and-fro blood flow of the iatrogenic pseudoaneurysm.

Figure 5.

A: Duplex ultrasound image shows a large pseudoaneurysm (pseudo) arising from the left profunda (prof) femoral artery with a clearly demonstrated neck and to-and-fro Doppler signal measuring approximately 6 mm in diameter B: The pseudoaneurysm (arrow) dissects and displaces into the adjacent femoral nerve (arrowhead).

Figure 6.

Intraoperative image exposing the left femoral nerve and associated vasculature, highlighted with red rubber ties. The incision extends into the coronal plane. The femoral and profunda femoral arteries lie medial to the nerve.

Case 3

A 20-year-old man[4] sustained a complex wrist fracture/dislocation that required open-reduction internal fixation. He presented to the neurosurgery clinic after this repair with left hand tingling and numbness in an ulnar nerve distribution and also profound grip weakness. Three months after the injury, he underwent surgery for exploration and repair with a 1.7-cm decellularized allograft. At the 8-month follow-up, there was no clinical or electro-physiological evidence of reinnervation of the ulnar nerve graft. The patient complained of persistent tingling and numbness, grip weakness, and progressive clawing of the hand. He had marked atrophy of the intrinsic muscles of the hand and absent sensation in the ulnar distribution. The patient again underwent surgery for reexploration, at which time an end-bulb neuroma was resected and sural nerve grafts were placed (Fig. 7B). Postoperative ultrasound effectively showed continuity of the nerve graft with no evidence of neuroma formation 6 or 12 months after surgery (Fig. 7C). The patient improved clinically with concordant EMG findings.[4]

Figure 7.

A: Graphic illustration of intraoperative repair demonstrating cable grafts sutured into the nerve defect in continuity. Copyright University of Miami Miller School of Medicine. Published with permission B: Intraoperative view after ulnar nerve repair with sural nerve allografts. From Berrocal et al: Limitations of nerve repair of segmental defects using acellular conduits. J Neurosurg 119:733–738, 2013. Published with permission C: Sagittal ultrasound image of the left ulnar nerve repaired with sural nerve grafts 12 months after repair showing fascicular profiles and the absence of a neuroma.

Case 4

The final presented case is of a 62-year-old woman who underwent a biopsy of a right-sided neck lymph node and presented to the neurosurgery clinic with complaints of right neck, shoulder, and arm pain (score 9 of 10) that began the day after surgery. The pain was constant and worse with activity. She also complained of upper-arm weakness and limited range of motion. Her physical examination demonstrated Grade 3/5 weakness and atrophy of a portion of the right trapezius. EMG revealed 1+ fibrillations (e.g., see http://courses.kcumb.edu/physio/2008%20EMG/cmap.htm) and decreased innervation of the spinal accessory nerve on the right in the corresponding musculature, which was 35% of the response compared with that of the normal left side. Ultrasound of the right supraclavicular fossa was performed, which revealed a Sunderland Grade 5 lesion involving the spinal accessory nerve with a 1.5-cm gap between the severed nerve ends and a 4-mm end-bulb neuroma (Fig. 8). In light of the ultrasound findings and her residual neurological function, the mutual decision to proceed with surgical repair of the right spinal accessory nerve was made.

Figure 8.

A: Sunderland Grade 5 injury of the spinal accessory nerve in the lateral aspect of the posterior triangle of the neck, with a gap (calipers) measuring approximately 1.5 cm between the severed nerve ends (white arrows), just medial to the edge of the trapezius muscle B: At the proximal nerve stump, there is a 4-mm end-bulb neuroma (white arrow).

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