Abstract
OBJECTIVE:
This study aims to discuss clinical characteristics, image manifestation and treatment methods of temporal bone lesions with facial paralysis as the main manifestation for deepening the understanding of such type of lesions and reducing erroneous and missed diagnosis.
METHODS:
The clinical data of 16 patients with temporal bone lesions and facial paralysis as main manifestation, who were diagnosed and treated from 2009 to 2016, were retrospectively analyzed. Among these patients, six patients had congenital petrous bone cholesteatoma (PBC), nine patients had facial nerve schwannoma, and one patient had facial nerve hemangioma. All the patients had an experience of long-term erroneous diagnosis.
RESULTS:
The lesions were completely excised by surgery. PBC and primary facial nerve tumors were pathologically confirmed. Facial-hypoglossal nerve anastomosis was performed on two patients. HB grade VI was recovered to HB grade V in one patient. The anastomosis failed due to severe facial nerve fibrosis in one patient. Hence, HB remained at grade VI. Postoperative recovery was good for all patients. No lesion recurrence was observed after 1–6 years of follow-up.
CONCLUSION:
For the patients with progressive or complete facial paralysis, imaging examination should be perfected in a timely manner. Furthermore, PBC, primary facial nerve tumors and other temporal bone space-occupying lesions should be eliminated. Lesions should be timely detected and proper intervention should be conducted, in order to reduce operation difficulty and complications, and increase the opportunity of facial nerve function reconstruction.
Introduction
The anatomical position of the temporal bone is deep. The petrosa is located between the occipital bone and the great wing of sphenoid bone, with an inclusive hearing organ and balancing organ. The temporal bone is an important part of the lateral skull base, has a complex adjacency relation, and is closely adjacent to the facial nerve, as well as to the internal carotid artery, sigmoid sinus, jugular venous bulb, lower cranial nerves, dura mater, temporal lobe, cerebella and other important structures. At the same time, temporal bone lesions can also invade the clivus, sphenoid sinus and nasopharynx, making disease diagnosis and treatment in this area very challenging [1, 2, 3]. Furthermore, emphasis for protecting hearing, balancing and facial nerve function are considered in clinical treatment.
The date description of 16 cases in this report
The date description of 16 cases in this report
Note: SP
Congenital petrous bone cholesteatoma (PBC) and primary facial nerve tumors belong to temporal bone space-occupying lesions, which has a low incidence rate [4, 5, 6, 7]. Its onset is not easy to detect and does not present obvious symptoms at the early stage. Hence, it can be easily ignored during evaluations. Its early symptom is facial paralysis for partial patients. However, it may be erroneously diagnosed as Bell’s palsy, in general [8]. Patients have accepted medication treatment and/or TCM acupuncture and moxibustion treatment, and missed the optimal opportunity for treatment, causing progressive lesions and invasion into hearing and balancing organs, as well as locations close to the great vessels, craniocerebral tissues and others [3]. This increases the difficulty of treatment and facial nerve function reconstruction. Therefore, there is an important need to deepen the understanding of the disease, in order improve the alertness early diagnosis and the timely detection of the lesion, and take proper measures for intervention. This study mainly discusses the clinical characteristics and treatment methods applied for patients with temporal bone lesions, taking facial paralysis as the main manifestation, including congenital PBC, facial nerve schwannoma (FNS) and hemangioma, in order to deepen the understanding of such type of lesions, and reduce the erroneous and missed diagnosis.
The axial (A) and coronal (B) views of the preoperative HRCT of the temporal bone shows abnormal soft tissue shadows in the right petrous bone. The axial (C) and coronal (D) views of the post-operative HRCT of the temporal bone shows that the lesions were completely removed.
The axial (A) and coronal (B) views of the preoperative HRCT of the temporal bone and the axial (C) and coronal (D) views of the preoperative MRI of the temporal bone revealed enhanced mass shadows from the geniculate ganglion to the vertical facial nerve in the left temporal bone.
Clinical data
A retrospective analysis was conducted on the clinical data of 16 patients with temporal bone lesions, including congenital PBC and primary facial nerve tumor, who were diagnosed and treated from 2009 to 2016 (Table 1). Facial paralysis was considered as the main manifestation for these patients. Among these patients, six patients had congenital PBC, nine patients had FNS, and one patient had facial nerve hemangioma. Furthermore, among these 16 patients, nine patients were male and seven patients were female; and the mean age of these patients was 57 years old (range: 45–68 years old). Facial nerve function was graded according to the House-Brackmann (HB) system. Preoperative HB was grade III in one patient with PBC, grade V in four patients with PBC and two patients with facial nerve tumors, and grade VI in one patient with PBC and eight patients with facial nerve tumors. The mean time from facial paralysis occurrence to correct diagnosis was 9.5 years, with a range of 7–16 years. For all patients, the tympanic membrane was intact, no ear drainage history was found, and the early symptoms were facial paralysis and hearing loss. Other symptoms were dizziness, facial numbness, tinnitus and others. All patients were diagnosed with Bell’s palsy, and received medication treatment, and TCM acupuncture and moxibustion treatment. Comprehensive clinical and otoneurology examinations were conducted for the patients, and the symptoms and signs were recorded. Facial nerve function was graded according to the HB system. For the six patients with PBC, the lesions were completely excised by subtotal petrosectomy, and pathology revealed cholesteatoma. For 10 patients with primary facial nerve tumors, the lesions were completely excised using the translabyrinthine or transmastoid approach, and pathology revealed FNS in nine patients and hemangioma in one patient.
Typical cases
Case 3
A 57-year-old male patient had hearing loss at his right ear for 10 years. The patient suffered from progressive facial paralysis for 8 years, was diagnosed with Bell’s palsy, and received medication treatment and TCM acupuncture and moxibustion treatment. The tympanic membrane was intact and HB grade was V. A profound deafness of right ear occurred. Preoperative high-resolution CT (HRCT; axial [A] and coronal [B] views) of the temporal bone revealed that the petrous bone was damaged and invaded at middle ear and mastoid. Hence, subtotal petrosectomy was performed to completely remove the lesions. During the operation, the lesions involved the internal ear and labyrinth, and the facial nerve fiber was still continuous. Lesion removal and facial nerve decompression were simultaneously performed. Post-operative HRCT (axial [C] and coronal [D] views) of the temporal bone revealed that the lesions were completely removed, and pathology revealed cholesteatoma. After six years of follow-up, HB grade V recovered to HB grade III, and no cholesteatoma recurrence was identified (Fig. 1).
Case 12
A 68-year-old male patient suffered from progressive facial paralysis and had hearing loss of his left ear for 10 years. The patient was diagnosed with Bell’s palsy, and reveived medication treatment and TCM acupuncture and moxibustion treatment. The tympanic membrane was intact and HB grade was VI. A profound deafness of the left ear occurred. Preoperative HRCT (axial [A] and coronal [B] views) of the temporal bone revealed facial nerve space-occupying lesions along the left side. Preoperative magnetic resonance imaging (MRI; axial [C] and coronal [D] views) of the temporal bone revealed enhanced mass shadows from the geniculate ganglion to the vertical facial nerve in the left temporal bone. The patient was diagnosed with FNS and received facial nerve tumor excision, but refused to undergo facial nerve function reconstruction. After surgery, the FNS was pathologically confirmed. After three years of follow-up, HB remained at grade VI and no tumor recurrence was found (Fig. 2).
Surgical approach
The operation method is determined according to the location of the lesion, scope, preoperative hearing level, facial nerve function, and the basic conditions of the patient.
Subtotal petrosectomy
Lesions were located in the petrosa in six patients with PBC. Part of these lesions invaded the middle ear and mastoid. For the patients without practical hearing, most of the temporal bone structures were excised by subtotal petrosectomy. When lesions were involved in the internal ear labyrinth, the labyrinth tissue was excised simultaneously.
Transmastoid approach
Five patients underwent the transmastoid approach. The 15
Translabyrinthine approach
Five patients underwent the translabyrinthine approach, and suffered from exposed lesions in the geniculate ganglion, labyrinth and internal auditory canal. At the same time, the middle ear and mastoid lesions were excised. During the operation, facial nerve function was protected as much as possible. When the tumor was completely excised, abdominal fat was allowed to fill the internal auditory canal to repair the cerebrospinal otorrhea.
Postoperative treatment
After surgery, the patient was transferred to the Intensive Care Unit (ICU) for one day to monitor the vital signs, neural reflex, cerebrospinal leakage and other conditions of the patient. After anti-infection for seven days, the patient was discharged after removing the suture.
Results
General conditions
Lesions were completely excised in all 16 patients. However, patients individually experienced long-term dizziness or disequilibrium, while other conditions were steady and no special conditions were found.
Facial nerve function protection and reconstruction
Preoperative HB grade III was recovered to HB grade II after surgery in one patient with PBC. Preoperative HB was grade V for four patients with PBC and two patients with facial nerve tumors. In two patients, postoperative HB recovered to grades III and IV, respectively. In two patients, postoperative HB remained at grade V; and in two patients, postoperative HB developed to grade VI. Preoperative HB was grade VI in one patient with PBC and eight patients with facial nerve tumor, in which, one patient underwent facial-hypoglossal nerve anastomosis; and facial nerve function HB grade VI was recovered to grade V. In eight patients, postoperative HB remained at grade VI, in which, facial-hypoglossal nerve anastomosis failed in one patient due to severe facial nerve fibrosis. Most patients continuously suffered from facial paralysis for many years before surgery. Hence, facial nerve function reconstruction was not attempted.
Discussion
A retrospective analysis is conducted on the clinical data of patients with temporal bone lesions, taking facial paralysis as the main manifestation, including congenital PBC and primary facial nerve tumors. Common characteristics of patients: progressive or complete facial paralysis, and hearing loss, with or without dizziness. Furthermore, no ear drainage was found, the tympanic membrane was intact, the onset undetectable, and non-specific manifestations were ignored at the early stage. In patients with facial paralysis, these patients were diagnosed with Bell’s palsy, and received medication treatment and TCM acupuncture and moxibustion treatment. The lesions weren’t found in time. However, the long-term erroneous diagnosis caused disease progression and caused the patient to miss the optimal opportunity for treatment. Due to the low incidence rate and insufficient understanding of disease, the diagnosis and treatment were very challenging. The primary task of erroneous diagnosis avoidance is to deepen the understanding of this disease, improve the alertness of non-specific symptoms at the early stage, and perfect the imaging examination timely and purposefully, in order to enhance the mastery of the key points for disease diagnosis and treatment.
Petrous bone cholesteatoma
PBC is a rare epidermoid cyst that invades the petrous bone and occupies
The PBC diagnosis and treatment were very challenging due to the slow and silent growth pattern, the complex adjacency relation to the skull base, close proximity to important neurovascular structures, local invasiveness and recurrence tendency [1, 2]. PBC has risks that may damage the internal carotid artery, jugular venous bulb, sigmoid sinus, dura mater and other important structures that threaten the life of the patient [9]. For PBC, surgical treatment is mainly applied, with main surgical approaches including the transmastoid approach, translabyrinthine approach, transcranial fossa approach, the combination approach of the transcranial fossa and mastoid, and the combination approach of the transmastoid and sphenoid sinus. Hearing preservation surgery is reserved for limited PBC. For patients with good preoperative hearing, the transmastoid approach and transcranial fossa approach can be applied. The subtotal petrosectomy can clearly expose the lesions, and is beneficial for completely excising the cholesteatoma. However, this can also expose the facial nerve when the middle ear and mastoid lesions were treated. Essentially, the ear vesicle can be excised until it reaches the petrosal apex, internal carotid artery, internal auditory canal, clivus and other positions, which is applicable for patients without practical hearing before the operation. Dura mater treatment: Upon full exposure, the cholesteatoma matrix was peeled from the dura mater. When adhesion was conducted, bipolar coagulation was applied to manage the suspicious dura mater, making the cholesteatoma inactive. However, there is a risk of cerebrospinal leakage. In general, without this special repair, the free muscle flap can be quickly inserted until the subarachnoid space, in order to close the leakage point. For large defects, a muscle flap, fascia and fibrin glue can be applied for blocking [10]. Jugular venous bulb treatment: Before the operation, nuclear magnetism venography can be applied to analyze the relation among lesions, the jugular venous bulb, and lateral vein system conditions. When lateral vein system development is incomplete, jugular venous bulb sacrifice means that the main venous drainage is blocked in the brain, causing intracranial hypertension [3].
In this study, profound deafness occurred in the affected side before the PBC operation in six patients. Subtotal petrosectomy can be applied to remove these lesions. If the internal ear labyrinth is invaded, the affected tissue can be simultaneously excised in the labyrinth. After 1–6 years of postoperative follow-up, no lesion recurrence was revealed.
Primary facial nerve tumor
Facial nerve tumors are a kind of primary benign tumors in the facial nerve, which has a low incidence rate. Some scholars have found that in 1,400 cases of temporal bones, metastatic, adjacent and malignant tumors that involve the facial nerve were more common by approximately 16 times, compared to primary facial nerve tumors. For such phenomenon, there was only one case of neurogenic tumor [6]. The most common tumor is FNS. There are other kinds of tumors, including: geniculate ganglion hemangiomas (GGHs), glomus facialis and granular cell tumors. The most common early symptom is facial paralysis for facial nerve tumors, which presents with slow, aggravating and progressive facial paralysis. Sudden facial paralysis can also manifest in few cases. In this study, 10 patients had facial nerve tumors, in which, nine patients had progressive facial paralysis and one patient had sudden facial paralysis. At the early stage, these patients were erroneously diagnosed with Bell’s palsy.
Literatures reported that the most commonly involved segment for FNS is the geniculate ganglion (60%–66%), followed by the tympanic segment (53%) and the labyrinthine segment (50.6%–60%); and that these mostly involved multiple segments [11, 12, 13, 14, 15, 16, 17]. FNS exhibited slow growth, with the increase rate of 0.85–1.40 mm/year [12, 16]. In case of no other symptoms for FNS, intervention would not be needed, and facial nerve function would be maintained as much as possible. The intervention indication is the significant growth of the tumor. For FNS with an HB grade of more than III, the combination of FNS excision and facial nerve function reconstruction can be applied using the transcranial fossa approach, transmastoid approach, translabyrinthine approach, or combination approach, according to tumor size, position, patient symptoms and preoperative hearing. In addition, Gamma knife surgery is an effective method for primary or residual FNS [18]. In this study, nine patients had the FNS, in which, four patients underwent the translabyrinthine approach and five patients underwent the transmastoid approach. These lesions were completely excised.
GGHs are rare vascular malformations that mainly involve the geniculate ganglion, and occupy 0.7% of the vasculopathy in the temporal bone [19]. Due to its slow growth, facioplegia occurred in disproportional sizes, that is, the tumor volume was small. In addition, facial nerve function disorder occurred. This was considered to be possibly related to nerve ischemia due to blood supply stealing. GGHs may cause cochlear fistula and sensorineural hearing loss in approximately 25% of patients [8]. Imaging is a diagnosis key. Temporal bone HRCT revealed that the facial nerve canal was enlarged in the lesion area, and presented with an irregular and amorphous edge. Furthermore, a nodular spicule was found. Fine spots were calcified with the general manifestation of a wormy appearance [7, 20]. MRI T2 weighted image revealed unevenly high signals with point-like low signals. In case of no facial paralysis or deafness, observation was conducted. For facial paralysis, when initial records revealed an HB grade of more than III, a protected facial nerve tumor excision can be performed. When facial nerve was excluded, facial nerve transplantation and other facial nerve function reconstructions were performed. As shown in the Case 11 in this study, GGHs were found in the internal auditory canal. After tumor excision, facial-hypoglossal nerve anastomosis was performed during the second period.
Facial nerve protection and function reconstruction
It is vitally important for patients to undergo facial nerve function prognosis. It is of significant meaning for function recovery to ensure facial nerve integrity. In case of any severe damage to the facial nerve, lesion excision can be considered. Meanwhile, facial nerve function reconstruction would performed, such as nerve transplantation and facial-hypoglossal nerve anastomosis [2, 4, 10]. The specific choice can be determined according to the facial nerve damage level, its length, the involved segment and the duration of the facial paralysis. Sanna et al. analyzed 213 cases of facial nerve transplantation, including vestibular schwannoma, meningeoma, facial nerve tumors and PBC. It was found that PBC prognosis was the worst, because preoperative HB grade was more than III for most PBC cases, with relatively long-term facial paralysis. In addition, for patients with facial paralysis for more than one year, facial-masseter nerve transplantation or facial-hypoglossal nerve anastomosis were performed, with a best effect HB grade of III [3].
In this study, preoperative HB grade III was recovered to HB grade II in one patient after cholesteatoma excision combined with facial nerve decompression was performed. For the remaining 15 cases, HB was grade V or above upon visiting a doctor. HB grade was VI for the 11
Conclusion
For patients with progressive or complete facial paralysis, especially patients with hearing loss or dizziness, imaging examination should be perfected in a timely manner. The possibility of PBC, primary facial nerve tumor and other temporal bone space-occupying lesions should be eliminated. It is important value for the diagnosis and treatment of such type of lesions to apply CT and MRI. The timely detection and intervention of these lesions should be performed, in order to undertake proper measures, reduce operation difficulty and complications, and increase the opportunity for facial nerve reconstruction.
Conflict of interest
The authors declare that they have no competing interests.