2017-18 HSC Section 4 Green Book

Original Investigation Research

Early Nerve Grafting in Patients With Facial Paralysis

Table 3. Patterns of Recovery After Nerve Grafting in 19 Patients

Change in Facial Asymmetry Index, mm At Rest With Smile

Time to Facial Reanimation Surgery, mo

Time to Recovery, mo

Total Paralysis Duration, mo

Smile Recovery Scale Score

Patient No./ Sex/Age, y

Synkinesis

Type of Nerve Graft

1/F/55 2/M/59 3/F/28 4/M/36 5/F/50 6/F/53 7/F/60 8/M/41 9/M/69 10/M/42 11/M/38 12/M/47 13/M/38 14/M/46 15/M/37 16/F/47 17/M/63 18/F/35 19/F/46

Masseteric Masseteric Masseteric Masseteric Masseteric Masseteric Masseteric Masseteric Masseteric Masseteric Masseteric Hypoglossal Masseteric Hypoglossal Hypoglossal Hypoglossal Masseteric Masseteric Hypoglossal

6 7 7 8 8 9 9 9 9

6

12 19 13 14 14 12 12 12 15 14 18 24 20 22 30 30 24 25 32

3 3 4 3 4 3 3 4 3 3 4 3 3 3 3 3 2 3 3

1 1 0 1 2 1 2 0 1 1 1 1 1 1 1 1 1 1 1

2.8 1.3 4.3 2.3 1.9

4.0

12

22.2 10.8

6 6 6 3 3 3 6 3 6

8.9

13.1 11.1

0

NA

NA

2.3

13.1

NA NA

NA NA

11 12 12 14 16 18 18 18 19 20

0.2

8.4

12

10.4

18.0

6 6

0

7.7

9.5 5.1 3.4

18.5

12 12

5.1

15.0

6 6

NA

NA

2.1 2.5

6.5 9.2

12

Abbreviation: NA, not available.

tial benefit of shortening the overall duration of significant paralysis, aswell as earlier and better recovery. However, early nerve grafting may be premature and unnecessary if sponta- neous recovery is impending but not detected at the time of intervention. Premature nerve graftingmay subject some pa- tients to unnecessary surgery, with associated morbidities. In this study, we have shown that the risk of premature fa- cial nerve exploration based on a lack of recovery over the first 6postoperativemonthswas 0%(0of 10). This findingwas sup- ported by the complete absence of EMG response and facial muscle contraction to direct facial nerve stimulation. At the main facial branch, pes, or individual peripheral facial nerve branches, direct facial nerve stimulation is expected to cap- ture any axonal response, without the ambiguity of surface EMG or percutaneous electroneurography. The clinical course of 8patients hereinwhodeclinednerve grafting provides insight into the natural course of the ana- tomically intact but injured facial nerve after CPA resection when the early facial nerve function is poor. Without surgical intervention, facial nerve function in patients with HB grade V or VI after CPA tumor resectionwill likely remain poor when there is no clinical evidence of improvement over the first 6 postoperative months. Nerve grafting in this group offers the potential for restoring function of their native facial muscles. Furthermore, satisfactory facial reanimation surgery in this group after excessive delay before intervention will likely re- quire transfer of functional muscle units such as the tempo- ralis or gracilis. The total duration of paralysis is a reflection of how long the facialmuscles are denervated.While this duration is short- ened by early nerve grafting, it also depends on the type of

life implications and time-sensitive nature of any potential in- tervention. Several studies 7-10 have failed to show any corre- lation among tumor size, intraoperative response to nerve stimulation, intraoperative stimulation thresholds, and pa- tient age, sex, and postoperative EMG. Axon and Ramsden 17 evaluated 184 patients with facial paralysis after vestibular schwannoma resection and concluded that the severity of im- mediate postoperative clinical facial functionwas themost ac- curate predictor of long-term outcomes. For patients starting with HB grade V or VI function after vestibular schwannoma resection, our group previously reported that the postopera- tive rate of recoverywas themost reliablepredictor of poor out- come after 1 year. 11 Our group’s predictivemodel using the rate of functional improvement as the sole independent variable anticipated poor outcome before 1 year in more than 50% of caseswith97%sensitivity and97%specificity. 11 Using thepost- operative rate of recovery during the first 6 months after CPA tumor resection as a sole predictor, we prospectively strati- fied patients herein with facial paralysis, despite a preserved facial nerve, into an intervention group and a noninterven- tion group. The nonintervention group was expected to have satisfactory spontaneous facial function recovery without nerve grafting. We offered the intervention group facial nerve grafting (before 12 months after surgery) using the masse- teric or hypoglossal nerve as the donor nerve if they showed no clinical signs of recovery over the first 6 postoperative months. The rationale for grafting the nonfunctional yet ana- tomically intact facial nerve is to provide axonal input distal to the site of injury in the internal auditory canal. Recom- mending early nerve grafting to a patient with facial paraly- sis, despite an anatomically intact facial nerve, has the poten-

(Reprinted) JAMA Facial Plastic Surgery Published online November 19, 2015

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