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This was a retrospective study performed with 53 patients who experienced facial paralysis due to the removal of acoustic tumours and were surgically treated by hypoglossal-facial nerve ‘side’-to-side neurorrhaphy in our Department of Neurosurgery between June 2011 and September 2016. The inclusion criteria were as follows: (1) the patient developed facial paralysis after acoustic neuroma resection and had normal nerve function before the operation, (2) the patient’s age ranged from 16 to 70 years old, (3) at least one side of the sural nerve function was normal, (4) no contraindications for general anaesthesia, and (5) voluntary treatment via hypoglossal-facial ‘side’-to-side neurorrhaphy. Patients who did not meet the above criteria were excluded from the study. Before the removal of the acoustic tumour, no facial function deficit was observed in any of these patients. After surgery, the patients developed serious facial paralysis with a House-Brackmann (H-B) scale grade V or VI, even though their facial nerve was anatomically preserved during tumour removal. The patients were followed-up for one year after the neurorrhaphy. This study was approved by the local Ethics Committee of Beijing Tiantan Hospital, Capital Medical University, China (KY2017-006-02).
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The principal indication for hypoglossal-facial nerve ‘side’-to-side neurorrhaphy was significant incomplete facial paralysis due to facial nerve injury. The preservation of facial nerve anatomical structure after injury could allow some remnant facial axons to be conserved and/or lead to spontaneous regeneration. The standard hypoglossal-facial nerve ‘side’-to-side neurorrhaphy was performed using a predegenerated nerve autograft (PSNG) in each patient by the same neurosurgeon[11]. The use of a PSNG was based on the aim of improving axonal regeneration given the proliferation of its Schwann cells due to axotomies. This concept has been demonstrated in previous studies by other investigators as well as our own study[11]. Briefly, the surgical operation was performed under general anaesthesia. The ipsilateral hypoglossal nerve was exposed and identified using an electrostimulator while recording the active potential in the tongue muscle at the ipsilateral side through two inserted electrodes[12]. One half of the hypoglossal nerve was cross-sectioned at a site closely distal to the descending branch. The proximal extremity of the PSNG that was predegenerated one week prior to neurorrhaphy and removed from the ipsilateral sural nerve was surgically bridged end-to-‘side’ to the hypoglossal nerve at the partial cross-section site. The injured facial nerve was exposed from its main trunk to the bifurcation area as well as its two main branches within the parotid gland. An epineurium window was created using microsurgical scissors on the exposed facial nerve at each of the two main branches closely caudal to the bifurcation while carefully preserving the tissue structure. The distal extremity of the PSNG was divided into two ends that were then surgically bridged to the facial nerve, end-to-side, at each of the epineurium windows. Figure 1 illustrates the hypoglossal-facial nerve ‘side’-to-side neurorrhaphy. All patients underwent intense rehabilitation exercise after neurorrhaphy.
Figure 1. Schematic drawings showing hypoglossal nerve-facial nerve ‘side’-to-side neurorrhaphy using a predegenerated nerve autograft (PSNG). One-half of the hypoglossal nerve was cross-sectioned at a site closely distal to the descendens hypoglossi. The proximal extremity of the PSNG was surgically bridged end-to-‘side’ to the hypoglossal nerve at the partial cross-section site. An epineurium window was created using microsurgical scissors on the exposed facial nerve at each of the two or three main branches with careful preservation of tissue structure. The distal extremity of the PSNG was divided into two ends that were then surgically bridged to the facial nerve, end-to-side, at each of the epineurium windows.
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The clinical data of the 53 patients are shown above. Tumour-related clinical data were obtained from detailed surgical records of acoustic neuroma resection. Patients were included in the study only when their surgical record regarding the acoustic neuroma resection was complete and detailed. Among the included patients, 29 were female and 23 were male. The patients’ ages ranged from 19 to 68 years old with a mean ± standard deviation (SD) of 42.47 ± 13.18 years old. In the clinic, we followed the traditional route of repair and generally recommended patients undergo 3−6 months of observation after facial paralysis. The period from the onset of facial paralysis to the neurorrhaphy ranged from 1 to 84 months with a mean ± SD of 12.86 ± 16.26 months (only one patient insisted on undergoing the surgery 1 month after facial paralysis). To obtain accurate results, we did not exclude these data from calculations of significant differences. We further divided the patients into 3 subgroups according to the duration of facial paralysis to analyse the time pointsat which neurorrhaphy was performed. The patients were divided into short (≤ 6 months), medium (7−12 months) or long (≥ 13 months) period groups. According to the records, a solid tumour was found in 34 patients, and tight adhesion between the tumour and facial nerve was observed in 35 patients. The greatest tumour diameters ranged from 1.5 to 6.0 cm with a mean ± SD of 4.00 ± 1.10 cm. Before neurorrhaphy, electrophysiological examination was performed using electromyography (Nicolet EDX, VIASYS Health Care Inc., Madison, Wisconsin, USA) to detect F wave appearances in all patients. F waves are one of the late responses produced by the antidromic activation of motoneurons via supramaximal stimulation of the nerve trunk and indicates nerve conduction from the motoneuron cell body to the motor endplate, which has a persistence of typically 80%–100% (or at least above 50%) in intact muscles[13]. We found 19 patients with positive and 34 with negative responses for F waves. The H-B facial nerve scale was used as the main indicator to assess facial function Supplementary Table S1 (available in www.besjournal.com).
Patient No. Gender
(M/F)Age (years) FPD (months) GTD (cm) Tumour characteristics Adhesion between tumour and facial nerve (yes/no) F wave on EMG (yes/no) H-B grade DRE (month) Before neurorrhaphy After neurorrhaphy Descend
grade1 F 25 4 4 solid no yes VI II 4 2 2 M 35 6 4.3 solid yes yes VI II 4 12 3 F 42 6 2.5 solid yes no VI II 4 12 4 F 46 6 3.4 solid no yes VI II 4 3 5 M 65 6 4 cystic yes yes VI II 4 12 6 M 38 4 2.5 solid no no V II 3 6 7 F 39 5 1.5 solid no yes VI III 3 6 8 M 41 9 3.4 solid no no VI III 3 12 9 F 43 5 3.6 solid yes yes VI III 3 12 10 F 44 3 6 cystic no yes V II 3 6 11 F 46 3 3 cystic no yes VI III 3 12 12 F 51 12 5 cystic yes yes VI III 3 12 13 M 60 4 2.8 cystic no no VI III 3 6 14 F 64 4 2 solid no yes VI III 3 3 15 F 27 4 3 solid no no V II 3 12 16 M 19 13 6 solid yes yes VI IV 2 6 17 M 19 24 4 cystic yes no V III 2 12 18 F 23 12 6 solid yes yes V III 2 12 19 F 24 6 6 solid no no VI IV 2 3 20 F 26 1 5 cystic no yes VI IV 2 12 21 F 26 6 5 solid yes no VI IV 2 3 22 F 30 3.5 3.5 solid yes yes V III 2 6 23 F 34 7 5 solid yes yes VI IV 2 12 24 M 35 7 4 solid yes yes VI IV 2 12 25 F 36 4 4 cystic no yes V III 2 12 26 M 41 5 4.5 solid yes no VI IV 2 12 27 M 42 11 5.5 cystic no no V III 2 3 28 M 48 5 4 cystic yes no V III 2 8 29 M 48 4 4 solid yes yes VI IV 2 6 30 M 50 3 4.7 solid yes no VI IV 2 12 31 F 51 13 3 cystic no no V III 2 12 32 F 51 13 3 solid no no VI IV 2 12 33 F 53 4 5 solid no no VI IV 2 6 34 M 61 12 3 solid yes no VI IV 2 12 35 F 66 10 3 solid yes no VI IV 2 6 36 M 52 18 4 solid yes yes VI IV 2 2 37 M 19 5 4.5 solid yes no VI V 1 0 38 F 24 13 4.5 solid yes no VI V 1 3 39 M 27 5 6 cystic yes no VI V 1 3 40 M 30 7 5 solid yes no VI V 1 6 41 M 40 11 4 cystic yes no VI V 1 2 42 F 45 84 4.8 cystic yes no VI V 1 6 43 F 46 22 4 solid yes no VI V 1 6 44 M 49 12 3.7 cystic yes no VI V 1 6 45 F 52 84 5 solid yes no VI V 1 2 46 M 63 33 2 solid yes no VI V 1 6 47 F 37 9 3 cystic yes no V V 0 1 48 F 42 13 5 solid yes no VI VI 0 6 49 F 42 30 3.2 solid no no VI VI 0 0 50 M 49 16 3 cystic yes no VI VI 0 3 51 M 54 33 5 solid yes no VI VI 0 6 52 F 63 6 3 cystic yes no VI VI 0 12 53 M 68 36 3.5 cystic yes no VI VI 0 6 Mean±SD − 42.47 ± 13.18 12.86 ± 16.26 4.00 ± 1.10 − − − − − − 7.23 ± 4.07 Item Q Item Q Item Q Item Q Item Q Item Q Item Q Total F 29 − − Solid 34 Yes 35 Yes 19 VI 42 VI 6 4 grades 5 M 24 − − Cystic 19 No 18 No 34 V 11 V 11 3 grades 10 IV 14 2 grades 21 III 14 1 grade 10 II 8 0 grade 7 Note. FPD: facial paralysis duration; GTD: great tumour diameter; EMG: electromyography; DRE: duration of rehabilitation exercises; Q: quantity; F: female; M: male. Table S1. Basic clinical data for the 53 patients in the research
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Age, the duration of facial paralysis and the greatest tumour diameter are expressed as the mean ± SD. GraphPad Prism 6.02 software was used for single-factor statistical analysis and one-way ANOVA. Continuous variables such as age, the duration of facial paralysis and greatest tumour diameter were analysed byunpaired T test. Other factors, including, F wave appearance, tumour adhesion to the facial nerve and tumour characteristics, were binary variables and were analysed by the chi-squared test. SPSS 19.0 software was used for logistic statistical analysis. P values ≤ 0.05 were considered statistically significant. For the logistic statistical analysis, separate odds ratios (ORs) and 95% CIs were also calculated. In addition, the patients were also divided into three subgroups according to the duration of facial paralysis for neurorrhaphy timing analysis. The three subgroups were analysed by one-way ANOVA followed by Tukey’s posthoc test for between-group comparisons.
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In this study, 36/53 patients showed better recovery of facial function, and 17/53 patients showed ordinary recovery. Clinical data were analysed using univariate analysis to determine which preoperative factors influenced treatment prognosis after neurorrhaphy.
The age distributions were 41.69 ± 2.19 years old in the better recovery group and 44.35 ± 3.37 years old inthe ordinary recovery group. There wasno significant difference between the two groups (P = 0.50). There was also no significant difference between the two groups (P = 0.57) in the gender distribution. The duration of facial paralysis before neurorrhaphy significantly differed between the better recovery group (9.29 ± 0.81 months) and the ordinary recovery group (24.24 ± 6.01 months; P = 0.0002). In the better recovery group, 25 patients had solid tumours, and 11 patients had cystic tumours. In the ordinary recovery group, 9 patients had solid tumours, and 8 patients had cystic tumours. No significant difference was established between the two groups intumour characteristics (P = 0.24). However, tumour adhesion to the facial nerve was observed in 19/36 patients in the better recovery group and in 16/17 patients in the ordinary group (P = 0.0079). A significant difference was also found between the two groups in F wave recordings (P = 0.0048). Before neurorrhaphy, 18/36 patients had positive F waves in the better recovery group. In contrast, only 1/17 patients had a positive F wave response in the ordinary recovery group.
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Univariate analysis of the duration of facial paralysis, F wave appearance and tumour adhesion to the facial nerve revealed significant differences between the better recovery and ordinary recovery groups. These factors were further analysed by logistic regression analysis, as shown in Table 1. The P values of the logistic regression analysis were 0.042 for the duration of facial paralysis (OR = 1.129, 95% CI = 1.004–1.270), 0.043 for F wave appearance (OR = 0.095, 95% CI = 0.010–0.924), and 0.031 for tumour adhesion to the facial nerve (OR = 0.063, 95% CI = 0.005–0.779), indicating that they influenced neurorrhaphy treatment prognoses.
Variable Unit P value Odds ratio 95% CI FPD month 0.042 1.129 1.004–1.270 F wave on EMG before the procedure yes/No 0.043 0.095 0.010–0.924 Adhesion between the tumour and facial nerve yes/No 0.031 0.063 0.005–0.779 Note. P values were determined by logistic test. Table 1. Logistic regression analysis results for neurorrhaphy
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Patients were divided into subgroups based on facial paralysis duration: 26/53 in the short-period subgroup, with facial paralysis durations of 4.54 ± 1.24 months ( ≤ 6 months); 12/53 in the medium-period subgroup with facial paralysis durations of 9.92 ± 1.98 months (7–12 months); and 15/53 in the long-period subgroup with facial paralysis durations of 29.67 ± 22.76 months ( ≥ 13 months). Statistical analysis performed using one-way ANOVA followed by Tukey’s post hoc test was performed according to the postoperative functional recovery of H-B grade and showed that there were significant differences among the three subgroups (P ≤ 0.0001). Upon analysis of the sets of two subgroups (Figure 2), a significant difference was established between the short- and long-period subgroups (P < 0.0001), although there was no difference between the short- and medium-period subgroups (P = 0.053) or between the medium- and long-period subgroups (P = 0.111).
Figure 2. Statistical analysis was performed using one-way ANOVA followed by Tukey’s post-hoc test according to the postoperative functional recovery on the H-B scale, and the results showed that there were significant differences among the three subgroups (****P ≤ 0.001). Upon analysis of sets of two subgroups (Figure 2), a significant difference was established between the short- and long-period subgroups (P < 0.001), although there was no difference between the short- and medium-period subgroups (P = 0.053) or between the medium-and long-period subgroups (P = 0.111).
Analysis of Preoperative Factors Influencing Hypoglossal-facial ‘Side’-to-side Neurorrhaphy for Facial Paralysis after Excision of Acoustic Neuroma
doi: 10.3967/bes2020.004
- Received Date: 2019-03-20
- Accepted Date: 2019-12-04
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Key words:
- Facial nerve injury /
- Nerve regeneration /
- Preoperative factors analysis
Abstract:
Citation: | SU Di Ya, WAN Hong, LI De Zhi, QIAO Hui, SCHUMACHER Michael, LIU Song. Analysis of Preoperative Factors Influencing Hypoglossal-facial ‘Side’-to-side Neurorrhaphy for Facial Paralysis after Excision of Acoustic Neuroma[J]. Biomedical and Environmental Sciences, 2020, 33(1): 30-36. doi: 10.3967/bes2020.004 |