Ulnar Nerve and Ulnar Artery Injury Caused by Comminuted Distal Radius Fracture.

INTRODUCTION: Distal radius fractures are one of the most frequent traumas encountered in daily orthopedic practice. With this case report, we would like to emphasize the significance of an unexpected associated ulnar nerve and artery injury with distal radius fracture to physicians. CASE REPORT: A 56-year-old male patient was evaluated in the emergency room after a motorcycle accident. The left wrist had a deformity and swelling, and about 3 × 1.5 cm of superficial skin abrasion was found in the volar surface of the wrist. It was noted that distal pulses were palpable, no neurological damage was found except hypoesthesia in the 5th finger. Radiologic examination revealed that the right shoulder was dislocated, and there was a displaced comminuted distal radius fracture in the left wrist with a non-displaced fracture of the ulnar styloid. The fracture was treated with open reduction and internal fixation using volar anatomic plate through the volar approach. After the surgery, pre-operative numbness did not resolve and opposing that expected; it increases with associated pain on the ulnar nerve innervated area within 30 days. The electromyographic analysis revealed severe partial ulnar nerve injury. The surgical exploration of the nerve was decided. The ulnar nerve was found to be trapped in scar tissue, and intimal injury and consequent thrombosis were observed at the ulnar artery.
CONCLUSION: Distal radius fractures are well-known fractures among the orthopedic surgeons; median nerve compression with a fracture is also within the expectation of the physician. However, the injury of the ulnar nerve and artery is unexpected. With this case report, we would like to emphasize the awareness of the diagnosis and treatment of this kind of associated unexpected ulnar nerve and artery injuries. Copyright: © Indian Orthopaedic Research Group.

The physician should remember that the ulnar neurovascular bundle may be vulnerable to tension caused by severely displaced distal radius fracture.

Introduction

Distal radius fractures are one of the most frequent traumas encountered in daily orthopedic practice. Approximately one-sixth of the fractures seen at the emergency rooms is distal radius fractures [1].

Although the most frequent neurological injury caused by these fractures is median nerve neuropathy, it has been reported in the literature that such fractures might cause ulnar nerve and artery injury.

This study aims to share the case of the ulnar nerve and ulnar artery injury following a closed distal radius fracture due to high energy trauma and our approach to this patient.

Case Report

A 56-year-old male patient was evaluated in the emergency room after a motorcycle accident.

In the patient’s physical examination, it was found that the right shoulder had an epaulet sign, the right arm was in external rotation and abduction, and the humeral head could be felt by deep palpation in the anterior part of the glenoid.

The left wrist had a deformity and swelling, and about 3 × 1.5 cm of superficial skin abrasion was found in the wrist’s volar surface.

It was noted that distal pulses were palpable, no neurological damage was found except hypoesthesia in the 5th finger.

Radiologic examination revealed that the right shoulder was dislocated, and there was a dorsally displaced severely comminuted distal radius fracture in the left wrist with a non-displaced fracture of the ulnar styloid (Fig. 1). The dislocated right shoulder was reduced under sedoanalgesia. The patient was operated electively 1 day after the injury.

Figure 1

Notice the displacement on lateral radiograph.

Under infraclavicular blockage anesthesia, with a pneumatic tourniquet inflated, approximately 10 cm skin incision was made on the volar aspect of the left wrist. The radial artery was explored and protected. After the fracture was reduced, it was temporarily fixed with 3 K-wires. Then, permanent fixation was achieved using a distal radius volar anatomic plate and screws (Fig. 2).

Figure 2

Post-operative anterior-posterior and lateral radiograms. Notice the smooth reduction.

The patient had symptoms of paresthesia and severe pain on the 4th and 5th fingers at 10th-day follow-up after the procedure.

He was closely monitored, as current symptoms did not improve, and electromyographic examination was obtained at the 4th week postoperatively. The electromyographic analysis revealed severe partial ulnar nerve injury. The surgical exploration of the nerve was decided.

Approximately 10 cm incision was made on the ulnar aspect of the wrist’s volar part. The ulnar nerve and the ulnar artery were found trapped inside the scar tissue (Fig. 3).

Figure 3

(a) The black arrow shows the starting point of compression on the ulnar artery and nerve, the asterix shows stenotic segment of the artery and the red arrow shows the ulnar nerve over the scar tissue. (b) Two black arrows demonstrate the thrombosis and ondulation on the ulnar artery.

The compressed ulnar nerve was released. Intimal injury and consequent thrombosis were observed at the ulnar artery. The thrombosed segment was excised till to the edge of the healthy vascular intimal layer (Fig. 4).

Figure 4

Asterix demonstrates the thrombosis and discoloration on the artery and yellow arrow shows the stenotic segment, notice the red coloration on the surface of the artery.

As the defect was approximately 5 cm, an anastomosis was planned with a vein graft from the forearm. About 8 cm of skin incision was made on the forearm’s volar side, 10 cm below the elbow joint, and 6 cm of vein graft was harvested from the basilic vein, reversed, and the defect was repaired with the graft (Fig. 5-7).

Figure 5

The yellow arrow shows the excised thrombotic segment of the ulnar artery.

Figure 7

The yellow arrows show the proximal and the distal side of the anastomosis. The blue arrow shows the body of the vein graft, which filled with blood, the evidence that the anastomosis is actively working.

(a) Exposure of the basilic vein, the yellow arrow shows the vein. (b) The harvested vein graft reversed and ready for anastomosis.

The ulnar artery was also decompressed against the probability of further compression. Four weeks after the second operation, finger hypoesthesia started to improve, and clinically, the pain diminished, and wrist and hand functions became better (in complete comparison).

The patient had full functionality and pain-free wrist without any neurovascular impairment; after the 8 months from the second surgery (Fig. 8-10).

Figure 8

Notice the appearance of the wrist and hand with full function, 8 months after the second surgery.

Figure 10

Notice the appearance of the wrist and hand with full function, 8 months after the second surgery.

Discussion

There have been the case reports and series regarding isolated ulnar nerve and ulnar artery injuries associated with distal radius fracture in the literature; however, and two authors have reported both artery and nerve injury. Regarding treatment and intraoperative findings, our report is unique in the literature.

While distal radius fractures are rarely associated with neurological injuries, the median nerve is most commonly affected by this type of fracture.

Its frequency has been reported in the literature ranging from 0.2% to 20% [2, 3, 4, 5, 6, 7, 8, 9]. In large series, ulnar nerve injury has been reported much less than the median nerve [2, 4, 6]. Isolated ulnar nerve injuries that reported in the literature mostly case reports (Table 1) [10, 11, 12, 13, 14, 15, 16, 17, 18, 19].

Table 1

Zoëga (1966) observed ulnar nerve palsy in three patients after a closed distal radius fracture; he emphasized that the abnormal dorsoradial displacement of the fracture can cause tension due to the contact pressure of the proximal fragment [10].

Vance and Gelberman (1978) reported ulnar neuropathy in three cases following a distal fracture in the radius. Compared to the common era of distal radius fractures, all cases sustained high-energy injuries, and all of the fractures had a more marked dorsal displacement than standard Colles’ fracture [11].

In their anatomical study, they found that the ulnar nerve was approximately 2 mm close to the fragments in a dorsally displaced distal radius fracture, and they emphasized that in an isolated distal radius fracture, ulnar nerve damage might occur as contusion or being tethered by intact distal ulna [11]. Furthermore, ulnar sided-hematoma may compress the nerve in Guyon’s canal [11].

If a distal radius fracture is paired with a distal ulna fracture, the likelihood of ulnar nerve damage is higher [11].

They suggested that the ulnar nerve in Guyon’s canal was less exposed to pressure than the median nerve did in the carpal tunnel [11].

They also suggested that if there is ulnar nerve deficit due to a distal radius fracture, immediate the closed or open reduction should be performed, and later if the neurological deficit does not improve in 24–36 h, and surgical decompression will be mandatory [11].

In an anatomical analysis, Clarke and Spencer (1991) found that the ulnar nerve had more mobility and extensibility than the median nerve; thus, the ulnar nerve was possibly less damaged than the median nerve after distal radius fractures [20].

Soong and Ring (2007) found that median nerve entrapment and ulnar nerve injury due to distal radius fracture were associated with high energy. We also justified this hypothesis in our case. Comparing with median nerve compression, ulnar nerve compression was less commonly encountered [16].

Furthermore, they postulated that the secondary ulnar nerve injury was not correlated with the pressure phenomenon, in contrast with the median nerve.

They disagreed with the idea that a displaced distal radius fracture was not very commonly associated with ulnar nerve injury; they argued that the ulnar nerve was more vulnerable to contusion and stretching than the median nerve due to its fixed position in the Guyon’s canal, but that, unlike the median nerve, the ulnar nerve was less affected by pressure-related injuries as it was outside of the carpal tunnel [16].

They recommended exploration of the nerve when there was a coexisting open wound with fracture associated with ulnar nerve injury; otherwise, close follow-up was recommended after the reduction [16].

In our case, the 5th finger had slightly hypoesthesia preoperatively, and we suggested that this was acute neuropraxia that could resolve spontaneously. In the post-operative 1 month follow-up, although the stretching effect of displaced fracture on the nerve resolved and hypoesthetic symptoms on the 4th and 5th fingers progressed. The decision of surgical exploration was made.

The injury of both the ulnar nerve and ulnar artery after distal radius fracture has been reported very rarely in the literature [12, 21].

Poppi et al. (1978) made a surgical exploration while the symptoms of ulnar nerve entrapment that did not resolve after 3 months from the injury in a conservatively treated distal radius fracture; found that the ulnar nerve, artery, and veins were trapped in scar tissue and the ulnar artery was thrombosed. They released the ulnar nerve but did not give additional detail about the ulnar artery in the report [12]. This report seems very similar to ours, but in

Conclusion

Distal radius fractures are well-known fractures among the orthopedic surgeons; median nerve compression with a fracture is also within the expectation of the physician. However, the injury of the ulnar nerve and artery is unexpected. With this case report, we would like to emphasize the awareness of the diagnosis and treatment of this kind of associated unexpected ulnar nerve and artery injuries.

Distal radius fractures are well-known fractures among orthopedic surgeons. However, associated injury of ulnar nerve and artery with a fracture is unexpected. The physician should keep in mind that the ulnar neurovascular bundle might be vulnerable to a tension caused by severely displaced distal radius fracture.