Effects of immediate and delayed facial-facial nerve suture on rat facial muscle

A Novel Approach to Facial Reanimation and Restoration Following Radical Parotidectomies

Background: Parotidectomies are indicated for a variety of reasons. Regardless of the indication for surgery, facial reanimation may be required because of facial nerve sacrifice or iatrogenic damage. In these cases, facial restoration performed concurrently with ablative surgery is considered the gold standard, and delayed reanimation is usually not attempted. Methods: A retrospective review of all patients who underwent parotidectomies from 2009 to 2022 in a single institution was performed. Indications, surgical techniques, and outcomes of an algorithmic template were applied to these cases using the Sunnybrook, Terzis scores, and Smile Index. A comparison was made between immediate vs. late repairs. Results: Of a total of 90 patients who underwent parotidectomy, 17 (15.3%) had a radical parotidectomy, and 73 (84.7%) had a total or superficial parotidectomy. Among those who underwent complete removal of the gland and nerve sacrifice, eight patients (47.1%) had facial restoration. There were four patients each in the immediate (n = 4) and late repair (n = 4) groups. Surgical techniques ranged from cable grafts to vascularized cross facial nerve grafts (sural communicating nerve flap as per the Koshima procedure) and vascularized nerve flaps (chimeric vastus lateralis and anterolateral thigh flaps, and superficial circumflex perforator flap with lateral femoral cutaneous nerve). Conclusions: The algorithm between one technique and another should take into consideration age, comorbidities, soft tissue defects, presence of facial nerve branches for reinnervation, and donor site morbidity. While immediate facial nerve repair is ideal, there is still benefit in performing a delayed repair in this algorithm.

Predictors of favorable outcome following hypoglossal-to-facial nerve anastomosis for facial nerve palsy: a systematic review and patient-level analysis of a literature-based cohort

OBJECTIVE

Facial nerve palsy is a debilitating condition that can arise from iatrogenic, traumatic, or congenital causes. One treatment to improve function of the facial muscles after facial nerve injury is hypoglossal-to-facial nerve anastomosis (HFA). HFA's efficacy and predictors of its success vary in the literature. Here, the authors present a patient-level analysis of a literature-based cohort to assess outcomes and investigate predictors of success for HFA.

METHODS

Seven electronic databases were queried for studies providing baseline characteristics and outcomes of patients who underwent HFA. Postoperative outcomes were measured using the House-Brackmann (HB) grading scale. A change in HB grade of 3 points or more was classified as favorable. A cutoff value for time to anastomosis associated with a favorable outcome was determined using the Youden Index.

RESULTS

Nineteen articles with 157 patients met the inclusion criteria. The mean follow-up length was 27.4 months, and the mean time to anastomosis after initial injury was 16 months. The end-to-side and end-to-end anastomosis techniques were performed on 84 and 48 patients, respectively. Of the 130 patients who had available preoperative and postoperative HB data, 60 (46.2%) had a favorable outcome. Time from initial injury to anastomosis was significantly different between patients with favorable and unfavorable outcomes (7.3 months vs 29.2 months, respectively; p < 0.001). The optimal cutoff for time to anastomosis to achieve a favorable outcome was 6.5 months (area under the curve 0.75). Patients who underwent anastomosis within 6.5 months of injury were more likely to achieve a favorable outcome (73% vs 31%, p < 0.001).

CONCLUSIONS

HFA is an effective method for restoring facial nerve function. Favorable outcomes for facial nerve palsy may be more likely to occur when time to anastomosis is within a 6.5-month window.

Facial Nerve Repair following Acute Nerve Injury

Background  Acute facial nerve iatrogenic or traumatic injury warrants rapid management with the goal of reestablishing nerve continuity within 72 hours. However, reconstructive efforts should be performed up to 12 months from the time of injury since facial musculature may still be viable and thus facial tone and function may be salvaged.

Methods  Data of all patients who underwent facial nerve repair following iatrogenic or traumatic injury were retrospectively collected and assessed. Paralysis etiology, demographics, operative data, postoperative course, and outcome were examined.

Results  Twenty patients underwent facial nerve repair during the years 2004 to 2019. Data were available for 16 of them. Iatrogenic injury was the common category ( n  = 13, 81%) with parotidectomy due to primary parotid gland malignancy being the common surgery ( n  = 7, 44%). Nerve repair was most commonly performed during the first 72 hours of injury ( n  = 12, 75%) and most of the patients underwent nerve graft repair ( n  = 15, 94%). Outcome was available for 12 patients, all of which remained with some degree of facial paresis. Six patients suffered from complete facial paralysis (50%) and three underwent secondary facial reanimation (25%). There were no major operative or postoperative complications.

Conclusion  Iatrogenic and traumatic facial nerve injuries are common etiologies of acquired facial paralysis. In such cases, immediate repair should be performed. For patients presenting with facial paralysis following previous surgery or trauma, nerve repair should be considered up to at least 6 months of injury. Longstanding paralysis is best treated with standard facial reanimation procedures.

Effectiveness of Surgical Treatment in Traumatic Facial Paralysis

INTRODUCTION

In the etiology of facial nerve palsy, trauma is the most important. Our aim was to present our experience gained by evaluating the surgical approaches we have used in extratemporal and intratemporal facial nerve injuries and their long-term results, also to contribute to the consensus that will be formed on this subject.

MATERIALS AND METHODS

Thirteen patients among 24 patients who underwent surgery with a diagnosis of traumatic facial paralysis were evaluated in this study. The clinical response of these patients to treatment was examined by classifying them according to the House-Brackmann classification in the preoperative and postoperative periods.

RESULTS

Of the 13 patients, 9 had fractures due to temporal bone trauma, and 4 had nerve damage in the extratemporal part of the facial nerve. In the treatment, facial nerve decompression was performed using the middle fossa approach in 9 patients with temporal bone fractures. In the 4 patients with extratemporal facial nerve injury, graft repair or primary suturing was performed. In the postoperative period, the stages of the patients were III or below in 12 patients (92%), and only 1 (8%) patient remained in stage IV.

DISCUSSION

When the postop conditions of the patients were examined according to House-Brackmann staging, it was observed that surgical treatment caused a significant improvement in the functions of the facial nerve.

CONCLUSIONS

Our results showed that surgery was an effective treatment method in patients with indications for traumatic facial paralysis.

The efficiency of ozone therapy and low-level laser therapy in rat facial nerve injury

PURPOSE

Comparison of low-level laser therapy (LLLT) and ozone therapy (OT) methods for the treatment of facial nerve injury (FNI) in rats, evaluated by histomorphometric measurement analysis.

MATERIALS AND METHODS

Thirty rats were randomly divided into control (C), LLLT, and OT groups. The left facial nerves (FNs) of all rats (n = 30) were used in this study. These were held in a surgical clamp for 30 s to create neuropathic damage. The non-injured right FNs of the rats in the control group formed the fourth, sham (S) group in this study (n = 10). Therefore the total number of evaluated samples was 40. The injured FNs of rats in the control group were left to heal spontaneously, whereas LLLT was applied for 21 consecutive days (output 100 mW/cm² and wavelength 850 nm) and OT (2 ml; 80 μm/ml) once every 2 days for 21 days.

RESULTS

After histomorphological evaluation, the OT group revealed statistically significant outcomes following FNI compared with the OT and control groups in terms of branching of nerve fibers (p = 0.003), nerve fiber diameters (p = 0.0398), nerve fiber areas (p = 0.042), and axon numbers (p = 0.0327). Although the LLLT group revealed a better healing process than the control group, the outcome was not statistically significant in terms of branching of nerve fibers (p = 0.6804), nerve fiber diameters (p = 0.7424), nerve fiber areas (p = 0.7048), and axon numbers (p = 0.7588).

CONCLUSIONS

OT resulted in statistically significant differences in outcome when compared with the LLLT and control groups, and provided a safe and effective treatment for FNI in rats. OT could therefore be considered as an alternative treatment of FNI. Clinical studies should now be performed to establish whether comparable results can be achieved in humans.

Treatment of complete facial palsy in adults: comparative study between direct hemihypoglossal-facial neurorrhaphy, hemihipoglossal-facial neurorrhaphy with grafts, and masseter to facial nerve transfer

BACKGROUND

The hypoglossal (with or without grafts) and masseter nerves are frequently used as axon donors for facial reinnervation when no proximal stump of the facial nerve is available. We report our experience treating facial nerve palsies via hemihypoglossal-to-facial nerve transfers either with (HFG) or without grafts (HFD), comparing these outcomes against those of masseteric-to-facial nerve transfers (MF).

METHOD

A total of 77 patients were analyzed retrospectively, including 51 HFD, 11 HFG, and 15 MF nerve transfer patients. Both the House-Brackmann (HB) scale and our own, newly-designed scale to rate facial reanimation post nerve transfer (quantifying symmetry at rest and when smiling, eye occlusion, and eye and mouth synkinesis when speaking) were used to enumerate the extent of recovery.

RESULTS

With both the HB and our own facial reanimation scale, the HFD and MF procedures yielded better outcome scores than HFG, though only the HGD was statistically superior. HGD produced slightly better scores than MF for everything but eye synkinesis, but these differences were generally not statistically significant. Delaying surgery beyond 2 years since injury was associated with appreciably worse outcomes when measured with our own but not the HB scale. The only predictors of outcome were the surgical technique employed and the duration of time between the initial injury and surgery.

CONCLUSIONS

HFD appears to produce the most satisfactory facial reanimation results, with MF providing lesser but still satisfactory outcomes. Using interposed grafts while performing hemihypoglossal-to-facial nerve transfers should likely be avoided, whenever possible.

Comparison of Direct Side-to-End and End-to-End Hypoglossal-Facial Anastomosis for Facial Nerve Repair

BACKGROUND

The hypoglossal facial anastomosis (HFA) is the gold standard for facial reanimation in patients with severe facial nerve palsy. The major drawbacks of the classic HFA technique are lingual morbidities due to hypoglossal nerve transection. The side-to-end HFA is a modification of the classic technique with fewer tongue-related morbidities.

OBJECTIVES

In this study we compared the outcome of the classic end-to-end and the direct side-to-end HFA surgeries performed at our center in regards to the facial reanimation success rate and tongue-related morbidities.

METHODS

Twenty-six successive cases of HFA were enrolled. In 9 of them end-to-end anastomoses were performed, and 17 had direct side-to-end anastomoses. The House-Brackmann (HB) and Pitty and Tator (PT) scales were used to document surgical outcome. The hemiglossal atrophy, swallowing, and hypoglossal nerve function were assessed at follow-up.

RESULTS

The original pathology was vestibular schwannoma in 15, meningioma in 4, brain stem glioma in 4, and other pathologies in 3. The mean interval between facial palsy and HFA was 18 months (range: 0-60). The median follow-up period was 20 months. The PT grade at follow-up was worse in patients with a longer interval from facial palsy and HFA (P value: 0.041). The lesion type was the only other factor that affected PT grade (the best results in vestibular schwannoma and the worst in the other pathologies group, P value: 0.038). The recovery period for facial tonicity was longer in patients with radiation therapy before HFA (13.5 vs. 8.5 months) and those with a longer than 2-year interval from facial palsy to HFA (13.5 vs. 8.5 months). Although no significant difference between the side-to-end and the end-to-end groups was seen in terms of facial nerve functional recovery, patients from the side-to-end group had a significantly lower rate of lingual morbidities (tongue hemiatrophy: 100% vs. 5.8%, swallowing difficulty: 55% vs. 11.7%, speech disorder 33% vs. 0%).

CONCLUSION

With the side-to-end HFA technique the functional restoration outcome is at least as good as that following the classic end-to-end HFA, but the complications related to the complete hypoglossal nerve transection can be avoided. Best results are achieved if this procedure is performed within the first 2 years after facial nerve injury. Patients with facial palsy of longer duration also have the chance for good functional restoration after HFA.

Delayed repair of facial nerve trauma: an experimental study in guinea pigs

CONCLUSION

The curative effect in the group where facial-facial anastomosis (FFA) was delayed for 7 days was similar to that in the immediate FFA group and had a better repair within 60 days.

OBJECTIVE

Due to the uncertainty about optimal timing of delayed facial nerve repair, we designed an experimental study in guinea pigs to find out the cut-off duration for delayed nerve repair.

METHODS

In this study, 64 male guinea pigs were randomly divided into 8 groups: normal, immediate FFA, and delayed FFA for 7, 14, 21, 30, 60, and 90 days (n = 6). Two months after suture of the nerves, the passing rate of myelinated fibers growing from the proximal to the distal stumps was calculated.

RESULTS

The passing rates of myelinated fibers in the groups with immediate FFA and FFA delayed for 7 days were significantly higher than those in other delayed FFA groups and the difference was statistically significant (p < 0.05), whereas the passing rates of the groups where FFA was delayed for 60 and 90 days were apparently lower than those of the immediate FFA and other delayed FFA groups. Under the electron microscope, regenerated fibers of the groups with immediate FFA and FFA delayed for 7 days were very similar to the normal myelinated fibers.

Daily facial stimulation to improve recovery after facial nerve repair in rats

OBJECTIVE

To establish whether daily mechanical stimulation improves functional recovery of whisking after facial nerve transection injury and repair in rats.

METHODS

Forty rats underwent facial nerve transection injury and repair and subsequent quantitative facial movement testing. Animals were randomized into 2 experimental groups (n = 20 each). Both groups received daily 5-minute manual stimulation of their whiskers, with one group undergoing whisker protraction and the other, whisker retraction. Rats were tested on postoperative weeks 1, 4 through 8, and 15 via a validated, quantitative whisking kinematics apparatus. Whisks were counted and analyzed for whisking amplitude, velocity, and acceleration.

RESULTS

Animals receiving manual stimulation by passive protraction of their whiskers demonstrated significantly improved functional recovery at multiple time points during the 15 weeks compared with historical controls (P < .005; 1-tailed t test). Recovery was similar in the protraction and retraction groups, trending toward better whisking recovery in the protraction group.

CONCLUSIONS

Daily mechanical whisker stimulation via either protraction or retraction significantly improves recovery of whisking after facial nerve transection and repair. This finding supports the role of early soft-tissue manipulation after facial nerve repair and may have clinical implications for the postoperative management of patients after facial nerve manipulations.

Hemihypoglossal-facial neurorrhaphy after mastoid dissection of the facial nerve: results in 24 patients and comparison with the classic technique

OBJECTIVE

Hypoglossal-facial neurorrhaphy has been widely used for reanimation of paralyzed facial muscles after irreversible proximal injury of the facial nerve. However, complete section of the hypoglossal nerve occasionally results in hemiglossal dysfunction and interferes with swallowing and speech. To reduce this morbidity, a modified technique with partial section of the hypoglossal nerve after mastoid dissection of the facial nerve (HFM) has been used. We report our experience with the HFM technique, retrospectively comparing the outcome with results of the classic hypoglossal-facial neurorrhaphy.

METHODS

A retrospective review was performed in 36 patients who underwent hypoglossal-facial neurorrhaphy with the classic (n = 12) or variant technique (n = 24) between 2000 and 2006. Facial outcome was evaluated with the House-Brackmann grading system, and tongue function was evaluated with a new scale proposed to quantify postoperative tongue alteration. The results were compared, and age and time between nerve injury and surgery were correlated with the outcome.

RESULTS

There was no significant difference between the two techniques concerning facial reanimation. A worse outcome of tongue function, however, was associated with the classic technique (Mann-Whitney U test; P < 0.05). When HFM was used, significant correlations defined by the Spearman test were identified between preoperative delay (rho = 0.59; P = 0.002) or age (rho = 0.42; P = 0.031) and results of facial reanimation evaluated with the House-Brackmann grading system.

CONCLUSION

HFM is as effective as classic hypoglossal-facial neurorrhaphy for facial reanimation, and it has a much lower morbidity related to tongue function. Better results are obtained in younger patients and with a shorter interval between facial nerve injury and surgery.

Successful intramuscular neurotization is dependent on the denervation period. A histomorphological study of the gracilis muscle in rats

To characterize the extent to which reinnervation potential depends on the duration of denervation, intramuscular neurotization of the gracilis muscle was performed either immediately or 2, 4, 6, and 8 weeks after transection of the obturator nerve. For neurotization, the sciatic nerve was split into three fascicle groups and fixed intramuscularly. Muscle morphology after 6 weeks of regeneration was identified with anti-myosin immunohistochemistry and NADH staining. Newly formed motor endplates were characterized using acetylcholinesterase staining and electron microscopy. Wet muscle weight ratio indicated the functional state of synapses. Depending on the denervation period, three levels of regenerative outcome were evident. Best results were seen after immediate neurotization or after 2 weeks of denervation. Regeneration, although at a significantly lower level, also occurred after denervation periods of 4 and 6 weeks. Regeneration following neurotization after 8 weeks of denervation was negligible. Quantity and quality of motor endplate formation depended on the denervation period. Thus, in special clinical situations intramuscular neurotization within a distinct time window provides a good reconstructive option.

Functional Recovery After Facial and Sciatic Nerve Crush Injury in the Rat

OBJECTIVES

To systematically record rat facial nerve recovery following crush injury to the main trunk with respect to ocular and vibrissial function and to compare the rates of facial and sciatic nerve recovery from crush injury in the same animals. This serves as a means of validating the functional parameters of facial nerve recovery against the well-known measure of hind limb function, the Sciatic Function Index.

METHODS

The main trunk of the facial nerve and the proximal segment of the sciatic nerve were exposed in all animals. Both nerves were subjected to standardized crush injury and subsequent daily functional testing. After a plateau of functional recovery was achieved, the animals were killed, and the distances between the sites of injury and the end musculature were measured, which allowed determination and comparison of recovery rates in both systems.

RESULTS

All crush injuries resulted in loss of electrical conductivity, as proven by intraoperative proximal nerve stimulation. Recovery of ocular and vibrissial motor function occurred starting at postoperative day (POD) 9 and continuing through POD 20. Hind limb function returned later (POD 14-34); however, when corrected for distance, the sciatic recovery rate (2.26 mm/d) appeared to match that of the facial nerve (1.5-2.4 mm/d).

CONCLUSIONS

Recovery after facial nerve crush injury follows a predictable time course, and the rate of recovery is consistent with that of sciatic nerve injury. Return of the blink reflex, loss of vibrissial fibrillations, and return of vibrissial sweeping function appear to be internally consistent functional measures of facial recovery. These quantitative measures will be useful for future facial nerve manipulation studies.