Rehabilitation Surgery for Peripheral Facial Nerve Injury after Facial Trauma

To evaluate the effectiveness of peripheral facial nerve direct end-to-end anastomosis and/or nerve grafting surgery for patients with facial nerve injury after facial trauma.

Methods

Fifty-nine patients with peripheral facial nerve paralysis after facial injuries underwent facial nerve rehabilitation surgery from November 2017 to December 2021 at Ho Chi Minh City National Hospital of Odontology.

Results

All 59 cases of facial trauma with damage to the peripheral facial nerve underwent facial nerve reconstruction surgery within 8 weeks of the injury. Of these cases, 25/59 (42.3%) had end-to-end anastomosis, 22/59 (37.3%) had nerve grafting, and 12/59 (20.4%) had a combination of nerve grafting and end-to-end anastomosis. After surgery, the rates of moderate and good recovery were 78.4% and 11.8%, respectively. All facial paralysis measurements showed statistically significant improvement after surgery, including the Facial Nerve Grading Scale 2.0 (FNGS 2.0) score, the Facial Clinimetric Evaluation (FaCE) scale, and electroneurography. The rate of synkinesis after surgery was 34%. Patient follow-up postoperatively ranged from 6 to > 36 months; 51 out of 59 patients (86.4%) were followed-up for at least 12 months or longer.

Conclusion

Nerve rehabilitation surgery including direct end-to-end anastomosis and nerve grafting is effective in cases of peripheral facial nerve injury following facial trauma. The surgery helps restore nerve conduction and improve facial paralysis.

Keywords
facial paralysis; nerve anastomosis; nerve grafting; sural nerve; facial trauma

Facial Nerve Grading Scale 2.0
Score	Region
Score	Brow	Eye	NLF	Oral
1	Normal	Normal	Normal	Normal
2	Slight weakness > 75% of normal	Slight weakness > 75% of normal Complete closure with mild effort	Slight weakness > 75% of normal	Slight weakness > 75% of normal
3	Obvious weakness > 50% of normal Resting symmetry	Obvious weakness > 50% of normal Complete closure with maximal effort	Obvious weakness > 50% of normal Resting symmetry	Obvious weakness > 50% of normal Resting symmetry
4	Asymmetry at rest < 50% of normal Cannot close completely	Asymmetry at rest < 50% of normal	Asymmetry at rest < 50% of normal	Asymmetry at rest < 50% of normal
5	Trace movement	Trace movement	Trace movement	Trace movement
6	No movement	No movement	No movement	No movement
Secondary movement (global assessment)			Grade
0		None	I	4
1		Slight synkinesis; minimal contracture	II	5–9
2		Obvious synkinesis; mild to moderate contracture	III	10–14
3		Disfiguring synkinesis; severe contracture	IV	15–19
Reporting: sum scores for each region and secondary movement. NLF, nasolabial fold			V	20–23
			VI	24

%	Degree
0	No recovery
0< to <25	Poor recovery
25 to <50	Moderate recovery
≥50	Good recovery

Surgical methods	Number of cases N = 59 (100%)
Direct end-to-end nerve anastomosis	25/59 (43%)
Nerve graft	22/59 (37%%)
Combined method	12/59 (20%)

Facial nerve branches	Direct end-to-end (n = 81)	Nerve graft (n = 69)	Total
Main trunk	1	1	2
Frontal branches	9	12	21
Zygomatic branches	24	26	50
Buccal branches	41	30	71
Marginal branches	6	0	6

Features	Before		After surgery		P ^* * Wilcoxon Sign-Rank test.
Features	Mean ± CI	Median (quartile)	Mean ± CI	Median (quartile)
FNGS 2.0	16.8 ± 4.4	14 (14–21)	7.2 ± 3.2	7 (4–9)	< 0.001
FaCE	0.4 ± 0.2	0.43 (0.3–0.5)	0.8 ± 0.1	0.9 (0.8–1)	< 0.001
ENoG	0.1 ± 0.1	0 (0–0.1)	0.6 ± 0.3	0.6 (0.3–0.9)	< 0.001

	Surgical methods			P ^* * Kruskal Wallis test.
	End-to-end (n = 25)	Nerve graft (n = 22)	Combined (n = 12)	P ^* * Kruskal Wallis test.
FNGS 2.0	6 ± 2.9	8 ± 3	7.8 ± 3	0.015
FaCE scale	0.9 ± 0.11	0.82 ± 0.13	0.89 ± 0.1	0.019
ENoG	0.71 ± 0.25	0.47 ± 0.22	0.65 ± 0.25	0.004

	N	Time of surgery	Wound features	Surgical methods	Improvement of facial paralysis
Min Hu (2016)²2 Booth PW, Eppley B, Schmelzeisen R. Maxillofacial Trauma and Esthetic Facial Reconstruction. 2 ed. Elsevier; 2011	7	6–21 days	Facial injuries, after surgery	Sural nerve graft	HB II: 71.4%; HB III: 28.6%
Kanna (2020)³3 Khan T, Shah SA, Wahid A, Waraich RA. Peripheral nerve injury in maxillofacial trauma. J Head Neck Phys Surg 2015	18	Early (before 48 hours): 8 cases; late (7 months–5 years): 10 cases	After surgery and injuries	Direct end-to-end anastomosis, vascular nerve grafting, nerve transfer	Good improvement: 61.1%. No improvement: 16.7%
Fabienne Carré (2022)⁴4 Kahn JB, Gliklich RE, Boyev KP, Stewart MG, Metson RB, McKenna MJ. Validation of a patient-graded instrument for facial nerve paralysis: the FaCE scale. Laryngoscope 2001;111(03):387–398. Doi: 10.1097/00005537-200103000-00005 https://doi.org/10.1097/00005537-2001030...	31	Before 48 hours: 3 cases; Late: 29 cases	Injuries, after surgery, tumors, pathologies	Direct end-to-end anastomosis: 2 cases, nerve graft: 29 cases	HB III: 58.1%; HB IV: 6.5%; HB VI: 35.4
Fliss (2022)⁵5 Haginomori S-I. An electrophysiological prognostic diagnosis for facial palsy. Auris Nasus Larynx 2022	12	Acute: 9 cases; subacute (< 24 weeks)	Injuries, postoperative, pathological	Direct end-to-end anastomosis: 1 case, nerve graft:11 cases	58.3% return normal
Our study	59	Acute: 2 cases; subacute (< 1.5 months): 57 cases	Facial injuries	Direct end-to-end anastomosis: 25 cases; nerve graft: 22; combined: 12 cases	HB I–II: 27: 81.3%; HB III: 15.3%; HB IV: 3.4%

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[1] Address for correspondence Luan Viet Tran, Associate Professor, MD, PhD, Department of Otorhinolaryngology, Pham Ngoc Thach University of Medicine, 2 Duong Quang Trung Street, Ho Chi Minh 700000, Viet Nam (e-mail: luantranviet@gmail.com).