Intratemporal Facial Nerve Injuries Research Articles

Effectiveness of Surgical Treatment in Traumatic Facial Paralysis.

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

Results of Decompression With Middle Cranial Fossa Approach or Traumatic Intratemporal Fascial Nerve Injury

To present the results of the traumatic intratemporal facial nerve injury that have undergone facial nerve decompression by using middle cranial fossa (MCF) approach. A retrospective study Tertiary referral center In this study, 13 patients who developed facial paralysis due to temporal bone trauma and undergone decompression by using MCF approach in Department of Otorhinolaryngology of İzmir Katip Celebi University Research and Training Hospital between January 1993 and December 2012 were presented retrospectively. Patients were assessed in terms of side, etiology, fracture type, House-Brackmann (HB) grade, electroneuronography (ENOG), electromyography (EMG), hearing loss, operation time, and the region of the injury. The fracture was at the right side in 7 (53.8%) and at the left side in 6 patients (46.1%). The type of temporal bone fracture was longitudinal in 6 (46.1%), transverse in 2 (15.3%), and mixed in 5 patients (38.4%). Total axonal degeneration in EMG and ENOG were seen in all patients, who were HB grade 6 at preoperative assessment. Mean operation time was 30 days. The lesion in all patients was at the region of geniculate ganglion. There was conductive hearing loss in 7 patients (53.8%), sensorineural in 4 (30.7%), and mixed in 1 patient (7.6%); hearing was normal in 1 patient (7.6%). Seven patients (53.8%) improved to HB grade 2. In the light of the information obtained from HRCT, ENOG, and EMG, we believe that better results can be achieved with facial nerve decompression that is performed before 1 month, and geniculate ganglion region may be better controlled by MCF approach.

Management of Intratemporal Facial Nerve Injuries

Objective: Outcomes of facial nerve (FN) restoration and decompression in patients with total loss of FN function after temporal bone fracture were analyzed.

Facial motor nuclei cell loss with intratemporal facial nerve crush injuries in rats

Injuries of cranial nerves that are distal to but near the motor nucleus might result in retrograde motoneuron cell death. The hypothesis of this article is that an intratemporal crush injury of the facial nerve in rats can cause facial motor nuclei cell death. Prospective, randomized, controlled animal study. Sprague-Dawley rats were randomly divided into four groups: intratemporal sham, intratemporal crush injury, extratemporal crush injury, and extratemporal sham. The intratemporal (n = 9) and extratemporal crush injury (n = 4) groups underwent a 60-second crush of the nerve at the facial nerve tympanic segment or main facial nerve trunk distal to the stylomastoid foramen, respectively. The intratemporal sham group (n = 4) underwent identical exposure to the intratemporal crush without subsequent injury. Both sham groups and the extratemporal crush group were sacrificed at 4 weeks. The intratemporal crush group was subdivided into 4- (n = 4) and 8-week (n = 5) postinjury groups. Brain sections were stained with thionin and facial motor nuclei were counted under magnification. The contralateral uninjured facial motor nucleus was used to compare motor nucleus cell survival. Intratemporal crush injury resulted in increased cell loss at 4 (89.43% ± 8.57% standard error of mean) and 8 weeks (85.78% ± 3.15%) after injury compared to sham injury (119.09% ± 13.35%) (P <.05). No significant change in cell survival was noted between the distal crush (103.29% ± 6.34%) and sham group (111.71% ± 3.24%) (P >.05). A rat intratemporal crush injury resulted in approximately 15% facial motor nuclei cell loss compared to an intratemporal sham injury. An extratemporal crush injury did not lead to any significant facial motor nuclei cell loss. This might have future translational implications in humans with intratemporal facial nerve injuries.

The Effect of Surgical Timing on Functional Outcomes of Traumatic Facial Nerve Paralysis

The optimal timing for surgical exploration of traumatic facial paralysis to best preserve facial function is currently controversial. This article reviews the final outcomes of facial function in patients with traumatic intratemporal facial nerve injury according to the timing of surgical exploration. We performed a retrospective review of 58 patients with complete facial nerve paralysis caused by temporal bone fractures as a result of head trauma between 1998 and 2007. Patients were divided into three groups according to the type of trauma. The only difference between patients in each group was the timing of the surgical exploration. Characteristics assessed in the study included type of trauma, location of facial nerve injury, timing of surgical intervention, audiometric findings, surgical approach, and long-term follow-up of recovery of facial nerve function, as assessed by two facial nerve grading systems. The final functional gains in early-operated patients were 3.7 +/- 0.59 on the House-Brackmann (HB) scale and 75.6 +/- 10.88 on the Sunnybrook scale. The outcome in late-operated patients was 2.17 +/- 0.52 on the HB scale and 34.7 +/- 16.95 on the Sunnybrook scale, and that of nonoperated patients was 2.0 +/- 0.63 on the HB scale and 26.8 +/- 6.27 on the Sunnybrook scale. This study demonstrated that some patients with traumatic facial nerve paralysis who had nerve conduction studies consistent with a poor prognosis regained considerable facial function after early surgical intervention. However, late exploration after facial nerve paralysis did not result in positive outcomes, regardless of the type of temporal bone fracture or the site of injury, and no difference was observed compared with conservative treatment.

SP331 – A rat model for intratemporal facial nerve crush injuries

OBJECTIVE: 1. Explain the need for an animal model to study intratemporal injuries to the facial nerve. 2. Describe the first rat model of intratemporal facial nerve crush injury. STUDY DESIGN: Animal surgery protocol. SETTING: Animal laboratory. SUBJECTS AND METHODS: Although intracranial and extratemporal facial nerve injury models have been described, an intratemporal injury model is lacking. This model is needed for translational research aimed at improving nerve recovery in the fallopian canal. The laboratory setup, anatomy, and surgical technique are described. RESULTS: The success of the facial nerve crush injuries was apparent upon physical examination of the animals. Our animals were followed for at least eight weeks postoperatively, and no signs of significant weight loss or physical distress were observed. INTRODUCTION • Crush injury is favored over nerve transection because it eliminates variables associated with neural re-anastamosis. • Although intracranial facial nerve transection, extratemporal crush and transection, and rat middle ear anatomy have been well described, an intratemporal injury model is lacking1-5. • The purpose of this paper is to describe a simple, reliable, and reproducible method to create a crush injury in an intratemporal segment of the adult rat facial nerve. TECHNIQUE • A curvilinear incision was made on the shaved and prepped postauricular skin approximately five millimeters (mm) behind the ear. The skin was elevated in the subdermal plane towards the ear canal. • The sternocleidomastoid tendon was divided to provide better exposure of the nerve. The dorsal and caudal aspects of the ear canal were incised so that the canal incision was immediately lateral to the tympanic membrane. • The temporalis muscle inserting on this ridge anteriorly and the rhomboid capitis muscle inserting posteriorly were sharply incised and gently dissected caudally and rostrally off of the ridge of bone thereby exposing an approximately one centimeter portion of bone superior to the tympanic membrane (figure 2). • A 3 mm cutting burr was used to remove the lateral bony aspect of the epitympanic region, thereby exposing the ossicles. The ossicles were removed. • Using a 1 mm diamond burr, the bone covering the facial nerve was progressively removed beginning at the posterior aspect of the stylomastoid foramen and continuing antero-medially. Twitching of the ipsilateral vibrissae was often noted when approaching the intratemporal facial nerve. • Jewler’s forceps were then inserted through the middle ear, and the intratemporal portion of the facial nerve within the medial wall of the superior middle ear cavity was crushed firmly for one minute. • Loss of ipsilateral eye blink and vibrissae orientation and movement was evidence of a successful crush injury. Figure 1. An intact facial nerve is shown as it exits the stylomastoid foramen (solid arrow). The bony ridge (dashed arrow) separating the temporalis muscle anteriorly and the rhomboid capitis muscle posteriorly and the location of the large maxillary vein (arrowhead) running along the anterior-inferior quadrant of the tympanic rim are also pictured. Figure 2. A rat facial nerve is shown immediately after a controlled intratemporal crush injury. The intratemporal segment of the nerve is shown after it has been skeletonized (*) from the stylomastoid foramen (solid arrow) to the crush site (dotted arrow). RESULTS & CONCLUSION • Our group had reproducible surgical success amongst various investigators with multiple animals. • Animals were followed for at least eight weeks postoperatively, and no signs of significant weight loss or physical distress were observed. • This technique offers the unique opportunity to study intratemporal facial nerve crush injuries in the adult rat. • Future directions include exploring new therapeutic methods of enhancing neuronal cell survival and increasing neural regeneration following intratemporal nerve injury. REFERENCES 1. Hetzler LE, Sharma N, Tanzer L, et al. Accelerating functional recovery after rat facial nerve injury: Effects of gonadal steroids and electrical stimulation. Otolaryngol Head Neck Surg 2008;139:62-7. 2. Lal D, Hetzler LT, Sharma N, et al. Electrical stimulation facilitates rat facial nerve recovery from a crush injury. Otolaryngol Head Neck Surg 2008;139:68-73. 3. Mattsson P, Delfani K, Janson AM, et al. Motor neuronal and glial apoptosis in the adult facial nucleus after intracranial nerve transection. J Neurosurg 2006;104:411-8. 4. Hellstrom S, Salen B, Stenfors LE. Anatomy of the rat middle ear. A study under the dissection microscope. Acta Anat (Basel) 1982;112:346-52. 5. Judkins RF, Li H. Surgical anatomy of the rat middle ear. Otolaryngol Head Neck Surg 1997;117:438-47. 6. Sharma N, Cunningham, K, Porter RG, et al. Comparison of extratemporal and intratemporal facial nerve injury models. Laryngoscope 2009; Published online ahead of print. This work was funded by United States Department of Veterans Affairs pilot grant #B6175R.

Comparison of extratemporal and intratemporal facial nerve injury models

The purpose of this study was to compare functional recovery and motor nerve conduction following a distal extratemporal crush injury of the facial nerve to a more proximal intratemporal crush injury. Prospective, controlled animal study. Adult male Sprague-Dawley rats were divided into four experimental groups: 1) extratemporal crush, 2) extratemporal sham-operated, 3) intratemporal crush, and 4) intratemporal sham-operated. Each group had an n of 4-9. The facial nerve was crushed near its exit from the stylomastoid foramen for extratemporal facial nerve injuries and within the facial canal in the temporal bone for intratemporal facial nerve injuries. Recovery times for the return of facial nerve functional parameters were compared between the two injury models. Motor nerve conduction studies were also done weekly to quantify the changes in peak amplitude and latency of evoked response. Rats receiving the extratemporal facial nerve injury recovered full facial function by approximately 2 weeks postoperative (wpo) and displayed normal peak amplitude and latency recordings by 4 wpo. In comparison, rats receiving the intratemporal facial nerve injury failed to reach complete functional recovery at the end of 8 wpo. Although latency of evoked response returned to normal by 2 weeks following the intratemporal injury, peak amplitude remained approximately 70% below normal at the end of 8 wpo. An intratemporal crush of the facial nerve leads to significantly delayed functional recovery and decreased motor nerve conduction as compared to an extratemporal crush, indicating that the location of injury strongly influences the recovery outcome.

Zygomatic root approach

Conclusions. The zygomatic root (ZR) approach provides improved intraoperative exposure of the key areas around the geniculate ganglion without a craniotomy, combining the advantages of middle cranial fossa (MCF) and transmastoid extralabyrinthine (TMEL) approaches. The ZR approach may be useful in cases of traumatic facial palsy, Bell's palsy, iatrogenic facial palsy, superior semicircular canal dehiscence and primary cholesteatoma. Objectives. To describe and evaluate the new ZR approach technique in the treatment of traumatic intratemporal facial nerve injuries. Patients and methods. This is a prospective clinical study of three consecutive procedures performed between July 2007 and January 2008, and a detailed discription of the surgical technique. The setting is a tertiary referral center. The patients’ age range was 3–7 years. Interventions were based on drilling the ZR area extensively, so that the perigeniculate area was exposed through the space created between the middle cranial fossa basal dura and skeletonized external auditory canal. The ZR approach can be performed as an isolated technique or can be combined with an inferior mastoidectomy protecting the bony bridge between. Results. Two patients had a mixed-type fracture and one patient had a transverse fracture. All three patients received a ZR combined approach. There was no cerebrospinal fluid leak, hearing loss, tympanic membrane perforation or meatal stenosis.

Hypoglossal — facial nerve anastomosis: A review of forty cases caused by facial nerve injuries in the posterior fossa

Hypoglossal-facial anastomosis has been our procedure of choice in the repair of the permanently injured facial nerve in the cerebellopontine cistern, when the nerve cannot be primarily repaired. Total failures are few and complications are rare. Most results are good to excellent, if assessment is based upon realistic expectations. These include: 1. normal facial symmetry in repose, 2. good midface voluntary motion, 3. no reflex or emotional facial movement, 4. some synkinesis and donor-injected mass facial movement, and 5. surprisingly little functional loss from hypoglossal paralysis. Our experience indicates better results in younger patients and in those repairs completed shortly after injury. These findings correlate well with the experience gained in peripheral nerve repair in the extremities. There appears to be no absolute time period between injury and repair beyond which this anastomosis is definitely contraindicated. Finally, this procedure does not negate adjunctive plastic surgical procedures. Most of our patients have had tarsorrhaphy or physiologic protection of the eye, but few have had corrective cosmetic surgical procedures until the past few years. We have never used cervical sympathectomy to reduce the size of the palpebral fissure. Better surgical procedures to correct both extracranial and intratemporal facial nerve injuries have significantly reduced the indication for anatomosis procedures. Additionally, over the past two decades, the improved diagnostic and surgical techniques for posterior fossa tumors have considerably reduced the incidence of facial paralysis. As these trends continue, the number of patients requiring nerve anastomosis for facial paralysis will continue to decline and what was once the only surgical procedure to repair the paralyzed face will become a rare operation.

Nerve decompression for intratemporal facial nerve injuries

Traumatic facial paralysis is not altogether uncommon. Though incidence of postoperative facial plasy has declined considerably in recent years, thanks because of improvement in microsurgical techniques for mastoid surgery, yet accidents still happen occasionally. However, there seems to be a higher occurrence of facial paralysis due to increase in road side accidents. Results of surgery are rewarding, though recovery may not be complete. Present paper describes our experience of treating 40 such cases. However, cases requiring nerve decompression or end-to-end anastomosis procedures only have been included in the present study. Surgical technique has been briefly discussed along with relevant review of literature.

Intratemporal facial nerve injuries.

A summary of the results of operative intervention for intratemporal facial nerve injuries in 81 cases is given. Causes, preoperative assessment, and operative techniques are discussed. The necessity for a variation in surgical approaches is stressed, depending on location of injury and associated neurologic findings.

Management of intratemporal facial nerve injuries.

Management of intratemporal facial nerve injuries.

The opercular syndrome–diagnostic trap in facial paralysis

We describe a patient with a left facial paralysis and hemotympanum following left parieto-occipital skull trauma. The initial admission diagnosis of intratemporal facial nerve injury secondary to temporal bone fracture was incorrect. Normal facial movements during involuntary activity (yawning, laughing at a joke) and focal seizure activity on the paralyzed side of the face, seen subsequently, indicated the site of lesion as supranuclear. The diagnosis of opercular syndrome was made. This syndrome can result when the contralateral frontal lobe is injured. Supranuclear weakness of muscles supplied by the hypoglossal or spinal accessory nerves is also present. Unlike other central paralyses, the facial paralysis in operculum syndrome may not demonstrate "forehead sparing" and consequently it may be mistaken for a peripheral paralysis. The neuroanatomic basis for the syndrome is discussed. Signs and symptoms are outlined to help the otolaryngologist avoid this diagnostic pitfall.