Comparison of Complications after Revision Ulnar Nerve Surgery Performed under Regional versus General Anesthesia

Approximately one-third of patients experience persistent or recurrent ulnar nerve symptoms after initial cubital tunnel surgery; however, the success rate of revision surgery is much lower than primary surgery.[1] [2] When revision surgery is indicated, there is no clear consensus with respect to the best form of anesthesia. One previous study examined postoperative complications in local/regional anesthesia versus general anesthesia for hand surgery, which included 99 nerve decompression procedures, and found that local/regional anesthesia provided fewer overall postoperative complications.[3] In contrast, various studies suggest that patients with preexisting neuropathies are poor candidates for peripheral nerve block due to concern for a double-hit phenomenon.[4] The applicability of the double-hit theory in revision ulnar nerve decompression with regional anesthesia is unknown. As such, surgeons and anesthesiologists do not have clear guidance in the ideal method of anesthesia in patients undergoing revision ulnar nerve surgery.

We retrospectively reviewed all adult patients who underwent revision cubital tunnel surgeries at our institution from 2012 to 2020. Patients were classified based on primary mode of anesthesia: regional block or general anesthesia. Ultimately, 42 patients were compared with determine if there was an association of early postoperative complications based on the type of anesthesia utilized (regional anesthesia n = 11 and general anesthesia n = 31). Baseline characteristics including gender, body mass index, history of diabetes, peripheral neuropathy, thyroid disorders, and cervical radiculopathy were similar between groups; however, there was a difference in mean age (regional = 38 years vs. general = 50 years, p = 0.020) and preoperative electromyography abnormality (regional = 3 vs. general = 21 patients, p = 0.033). Prior ulnar nerve surgery consisted of in situ decompression in 17 versus 4 patients, subcutaneous transposition in 5 versus 9 patients, and submuscular transposition in 0 versus 6 patients, in the regional and general anesthesia cohorts, respectively. We noted that patients who received general anesthesia were 3.5 times more likely to be admitted overnight to the hospital compared with those who received regional blocks, most commonly for pain control (n = 10 vs. n = 1, respectively; p = 0.133).

Postoperative complications are shown in [Table 1]. The most common complication was worsening pain, which occurred within the first 2 weeks in all patients. One patient in the general anesthesia cohort had a hypotensive episode intraoperatively that led to numbness and neurologic deficits. Two patients in the general anesthesia group returned to the operating room for irrigation and debridement secondary to hematoma and infection. Two patients in the regional anesthesia cohort experienced worsening numbness in their hand following surgery, attributed to surgical site hematoma and edema, which improved without surgical intervention. There was no significant difference in patients who had worsened, unchanged, or improved McGowan scores between the two cohorts (p = 0.164, p = 0.316, p = 0.844, respectively).

Table 1 Postoperative complications

	Regional anesthesia	General anesthesia	p-Value
	(n = 11)	(n = 31)
Complications, n (%)	6 (54.5)	12 (38.7)	0.362
Worsening pain	4 (36.4)	5 (16.1)
Edema	1 (9.1)	3 (9.7)
Worsening numbness	2 (18.2)[a]	1 (3.2)[b]
Wound dehiscence	1 (9.1)[c]	1 (3.2)[c]
Infection (including suture abscess)	0 (0.0)	4 (12.9)
Hematoma/seroma	2 (18.2)	3 (9.7)
Return to OR	0 (0.0)	2 (6.5)
Rash	1 (9.1)	0 (0.0)
Nausea and vomiting	0 (0.0)	1 (3.2)
Surgical site bleeding	0 (0.0)	1 (3.2)

Abbreviation: OR, operating room.

^a Improved with observation.

^b Secondary to cerebral hypoperfusion.

^c Required return to OR.

We did not find any statistically significant difference in early (≤ 30 days) postoperative complication rates between patients who underwent revision ulnar nerve surgery under general versus regional anesthesia. Two patients in our study who received regional anesthesia experienced worsening numbness postoperatively; however, both instances may be explained by postoperative iatrogenic compression. If the double-hit phenomenon were to hold true in revision cubital tunnel surgery performed under regional anesthesia, it is plausible that clinical outcomes would not improve to the same magnitude. One prior study found no difference in outcomes between those who had surgery performed under general versus regional anesthesia.[5] Our experience supports this with postoperative McGowan scores improving to the same extent.

General anesthesia carries its own risks. Unfortunately, one patient in our study did sustain significant cerebral hypoperfusion and subsequent neurologic deficits. Additionally, patients who underwent revision surgery under general anesthesia were 3.5 times more likely to require hospital admission, which may impact decision-making at outpatient surgical centers.

While we noted no statistically significant difference in complication rate between the two cohorts, there are multiple “hits” that patients undergoing revision cubital tunnel are subject to, including local trauma from increased dissection around scarred nerves as well as hypoperfusion to the nerve following transposition. These additional insults to the nerve are independent of the form of anesthesia, suggesting that this patient population is already at an elevated risk. A recent study suggested that patients with preexisting neuropathies are at increased risk of new or worsening neuropathy after regional anesthesia.[4] Patients with refractory symptoms who are undergoing revision cubital tunnel would fall into this category. Additionally, patients who receive regional anesthesia may not be able to recognize concerning symptoms in the early postoperative period because of the block.

In summary, we did not observe a statistically significant difference in complication rates between regional and general anesthesia in revision cubital tunnel surgery, although there was a trend toward increased rates in regional anesthesia. Caution should be taken in this high-risk population in the immediate postoperative period as complications may be difficult to identify due to the ongoing regional anesthetic effects.

Publication History

Article published online:
14 October 2022

• References

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