Comparison between VII-to-VII and XII-to-VII coaptation techniques for early facial nerve reanimation after surgical intra-cranial injuries: a systematic review and pooled analysis of the functional outcomes

Anatomical feasibility study of the infraspinatus muscle neurotization by lower subscapular nerve

OBJECTIVES

To investigate the anatomical feasibility of the infraspinatus branch of the suprascapular nerve (IB-SSN) reconstruction by lower subscapular nerve (LSN) transfer.

METHODS

The morphological study was performed on 18 adult human cadavers. The length of the distal stump of the IB-SSN, the length of the LSN available for reconstruction and diameter of both stumps were measured. The feasibility study of the LSN to IB-SSN transfer was performed.

RESULTS

The mean length of the IB-SSN to the end of its first branch was 40.9 mm (±4.6). Its mean diameter was 2.3 mm (±0.3). The mean length of the LSN stump, which was mobilized from its original course and transferred to reach the distal stump of the IB-SSN was 66.5 mm (±11.8). Its mean diameter was 2.1 mm (±0.3). The mean ratio between LSN and IB-SSN diameters was 0.9 (±0.1). The nerve transfer was feasible in 17 out of 18 cases (94.4%).

CONCLUSION

This study demonstrates that direct LSN to IB-SSN transfer is anatomically feasible in most cases in the adult population. It may be used in cases of complex scapular fractures resulting in severe suprascapular nerve injury.

A case of facial nerve palsy caused by severe head injury treated by translabyrinthine approach

Background

Several treatments for traumatic facial paralysis have been reported, but the role of surgery is still controversial.

Case Description

A 57-year-old man was admitted to our hospital with head trauma due to a fall injury. A total body computed tomography (CT) scan showed a left frontal acute epidural hematoma associated with a left optic canal and petrous bone fractures with the disappearance of the light reflex. Hematoma removal and optic nerve decompression were performed immediately. The initial treatment was successful with complete recovery of consciousness and vision. The facial nerve paralysis (House and Brackmann scale grade 6) did not improve after medical therapy, and thus, surgical reconstruction was performed 3 months after the injury. The left hearing was lost entirely, and the facial nerve was surgically exposed from the internal auditory canal to the stylomastoid foramen through the translabyrinthine approach. The facial nerve's fracture line and damaged portion were recognized intraoperatively near the geniculate ganglion. The facial nerve was reconstructed using a greater auricular nerve graft. Functional recovery was observed at the 6-months follow-up (House and Brackmann grade 4), with significant recovery in the orbicularis oris muscle.

Conclusion

Interventions tend to be delayed, but it is possible to select a treatment method of the translabyrinthine approach.

Iatrogenic facial nerve injury in mastoidectomy: The impact of variables on the outcome

OBJECTIVE

To evaluate iatrogenic facial nerve injury in mastoidectomy and its paralysis improvement result after nerve injury management.

METHODS

A retrospective review of medical records of 21 patients with iatrogenic facial nerve injury following mastoidectomy who underwent nerve injury management in a tertiary referral center.

RESULTS

There were nine males and 12 females, with a mean age of 40.4 ± 15.1 years. Cholesteatoma was the most common primary pathology (76.2%). Mastoidectomy was canal wall up in 8 patients and canal wall down in 13. Nerve injury was due to drilling in 10 patients and sharp tools in 11. The tympanic segment of the facial nerve was the most common injured site (50.0%). Decompression was the most common nerve injury management method (52.4%). Other injury management methods were end-to-end anastomosis (14.3%), great auricular nerve graft (23.8%), and facial-hypoglossal nerve transfer (9.5%). No statistically significant correlation was found between facial nerve function 3-6 months after injury management and the following factors: age, gender, primary pathology, type of mastoidectomy, surgeon's experience, nerve injury site, mechanism of trauma, and nerve injury management method and timing.

CONCLUSION

Regardless of the surgeon's experience or technique applied, a meticulous approach may be more valuable in decreasing the chance of iatrogenic facial nerve injury.

Role of stem cells-based in facial nerve reanimation: A meta-analysis of histological and neurophysiological outcomes

BACKGROUND

Treatments involving stem cell (SC) usage represent novel and potentially interesting alternatives in facial nerve reanimation. Current literature includes the use of SC in animal model studies to promote graft survival by enhancing nerve fiber growth, spreading, myelinization, in addition to limiting fibrotic degeneration after surgery. However, the effectiveness of the clinical use of SC in facial nerve reanimation has not been clarified yet.

AIM

To investigate the histological, neurophysiological, and functional outcomes in facial reanimation using SC, compared to autograft.

METHODS

Our study is a systematic review of the literature, consistently conducted according to the preferred reporting items for systematic reviews and meta-analyses statement guidelines. The review question was: In facial nerve reanimation on rats, has the use of stem cells revealed as effective when compared to autograft, in terms of histological, neurophysiological, and functional outcomes? Random-effect meta-analysis was conducted on histological and neurophysiological data from the included comparative studies.

RESULTS

After screening 148 manuscript, five papers were included in our study. 43 subjects were included in the SC group, while 40 in the autograft group. The meta-analysis showed no significative differences between the two groups in terms of myelin thickness [CI: -0.10 (-0.20, 0.00); I² = 29%; P = 0.06], nerve fibers diameter [CI: 0.72 (-0.93, 3.36); I² = 72%; P = 0.6], compound muscle action potential amplitude [CI: 1.59 (0.59, 3.77); I² = 89%; P = 0.15] and latency [CI: 0.66 (-1.01, 2.32); I² = 67%; P = 0.44]. The mean axonal diameter was higher in the autograft group [CI: 0.94 (0.60, 1.27); I² = 0%; P ≤ 0.001].

CONCLUSION

The role of stem cells in facial reanimation is still relatively poorly studied, in animal models, and available results should not discourage their use in future studies on human subjects.

Injuries of the Peripheral Mandibular Nerve, Evaluation of Interventions and Outcomes: A Systematic Review

Trigeminal nerve injuries are common and there is currently no consensus on both timing and type of intervention to achieve the best outcomes. A systematic review was performed to compare the outcomes of the many different types of therapeutic interventions for nerve injury. PubMed, EBSCO, and Cochrane Review databases were used to search for studies published from January 1, 2000 to December 31, 2019. Included studies detailed treatment of an injury to peripheral branches of the trigeminal nerve, either known transection or injury causing persistent alteration in sensation. The primary outcome was functional sensory recovery via the Medical Research Council scale. Twenty studies were included, detailing outcomes of 608 subjects undergoing intervention for 622 nerve injuries. Surgical interventions were able to achieve functional sensory recovery in approximately >80% or more of the subjects. There was heterogeneity among how procedures were performed, timing to intervention, and methods of measuring recovery. The data of this study supports the ability of surgical intervention to achieve functional sensory recovery in a significant number of subjects, and found evidence for better outcomes with intervention closer to the time of injury.