DOI: https://doi.org/10.21203/rs.3.rs-2652876/v1
A 30-year-old man underwent a high-resolution computed tomography of both temporal bones as part of the assessment of horizontal rotatory vertigo, pulsatile tinnitus, and mild hearing loss. First, we observed a bilateral high-riding jugular bulb with a right jugular diverticulum. Then, the right jugular bulb and the diverticulum were dehiscent in mastoid cells and Trautmann’s triangle. This case report illustrates a new presentation of the dehiscent high-riding jugular bulb and jugular diverticulum. We believe it deserves to be shared.
The JB is the dilated venous junction that connects the SS to the IJV [2, 5, 10], close to several anatomic structures such as the middle and inner ears, and some cranial nerves [4, 5]. The HRJB represents a JB-location abnormality [1] that can still be asymptomatic or provoke hearing loss, vertigo, pulsatile tinnitus, or bleeding during ear surgery [9, 10]. In fact, the surgeon must check for this condition on clinical and radiological exams to keep the patient safe. We report an uncommon presentation of HRJB and JBD associated with the dehiscence of the mastoid cells and the Trautmann triangle, not included before in the literature.
A 30-year-old man, known for hiatal hernia and allergic rhinitis, presented to the oto-rhino-laryngology department of our hospital for horizontal rotatory vertigo, which provokes gait imbalance. In addition, the patient complained of pulsatile tinnitus, mild hearing loss, temporal headaches, and intermittent ear and neck pain. Next, no symptoms suggested upper respiratory or other recent infections. The patient had no history of recent trauma, addiction, ototoxic medication, visual troubles, or psychological disorders. On physical examination, the patient had an imbalanced gait, especially when his eyes were closed; the Romberg test was positive, and the neurological exam was normal. Further, on the otoscopic exam, no anomalies existed in both EAC. The eardrums had a normal color, without bulge, retraction, retrotympanic mass, or collection. The eyes, nose, throat, and neck examination were ordinary. Tonal audiometry depicted a right mild conductive hearing loss for 4000Hz frequency sounds with an air-bone gap of 20db. The tympanometry displayed a type A curve for both ears. Laboratory tests were normal. The patient underwent a temporal bone HRCT. First, in the right ear, the JB, well-circumscribed, had its roof reaching the BT and the inferior margin of the RW (Fig. 1a, b). It faced the hypotympanum, covered by a thin, intact, bony wall (Fig. 1c). Second, from its dome, a well-corticate thumb-like diverticulum protruded between the VA and the mastoid cells (Fig. 1a) and rose to the level of the PSCC (Fig. 1d). In addition, we observed multiple bony deficiencies in the mastoid sidewall of both JB and JBD (Fig. 1e, f, g); they were also dehiscent in Trautmann’s triangle (Fig. 2a, b, c). Next, in the left ear, the JB reached the basal turn of the cochlea (Fig. 2d, e). Thus, we confirmed the diagnosis of bilateral DHRJB associated with DJBD. After a discussion with the patient, the oto-rhino-laryngologist adopted the conservative option.
The petrous portion of the temporal bone can present several vascular variations, the most common of which is the HRJB [9, 10]. The definition of the HRJB is controversial since the authors disagree about the ear structure to consider as a landmark. Some authors proposed the inferior margin of the IAC [9], while others proposed the BT, the jugular foramen apex [5, 10], the hypotympanum, or the tympanic annulus [5]. Thus, the JB is high riding if it exceeds one of these elements. Sasindran et al. assert that the JB is high riding only if it invades the hypotympanum. Singla et al. suggested two diagnosis parameters to define an HRJB. The first is a distance between the JB dome and the RW or the IAC less or equal to 2mm. The second is a zero distance between the jugular fossa and the ES opening [5]. In addition, if the bony wall separating the JB from the surrounding structures is defective, the JB is called dehiscent [10]. Thus, a herniation may occur in the middle ear, auditory canal, cochlea, VA, FN canal, or PSSC [2]. Further, an outpouching growing from the JB dome is called JD. Some authors consider it a venous anomaly, while others consider it as a JB extended inside [5].
Okudera et al. reported the JB does not appear before two years old [1, 9, 10]. They studied aborted fetuses and children up to six years and speculated that, during the fetal period and first two years, bony and cartilaginous structures surrounding the JB prevent its development [1]. From the age of two, the standing posture provokes negative pulses in the cranial venous circulation enlarging the IJV-SS junction, forming the JB, and excavating the jugular fossa [1, 2]. The mechanism leading to an HRJB is still unknown. It may relate to the blood flow imbalance in the head venous system. Indeed, it may explain the right-side dominance of the HRJB. An embryologic asymmetry of the dural sinuses and a longer left brachiocephalic vein could increase the negative pulses (cited above) on the right side [9]. In addition, Kao et al. demonstrated that, parallel to an HRJB, a helical flow existed in the IJV [5]. Further, mastoid pneumatization affects the JB position [4, 5, 9], since it affects the location and curve of the SS [4]. Well pneumatization places the SS deep behind, and its vertical limb continues as the JB, after a gentle S-curve; the JB is low. In contrast, poor pneumatization pushes the SS upward, and as a result, makes the JB higher [4]. As speculated by Lyu et al., a correlation exists between the JB position and the semicircular canals orientation [5]. Age and gender may influence HRJB development since the frequency and size change with them. Friedmann et al. reported that the prevalence of HRJB was 1.7% in patients younger than 10 years old, increased with puberty and between the age of 30 and 50, beyond which it stabilized [2]. Wang et al. observed a decrease in the prevalence beyond the age of 60 and linked that to bony resorption attenuation and hormone level changes related to age [9]. However, this hypothesis seems not to be always true. Friedmann et al. reported some cases were younger than five years [2]. Aksoy et al. found, in their series, that 53% of children with HRJB were younger than two years, while 86% of them were older than 12 months. The earliest case they found was eight-month-old [1]. Such observations suggest the HRJB may be congenital, or it develops early. In the Zuniga study, 46.7% of the patients having an HRJB were younger than two years; there was no significant difference across age groups [10]. Wang et al. observed more HRJB in women; Friedmann et al. and Zuniga et al. did not find a significant difference between genders [2, 9, 10]. Next, they remarked that the mediolateral dimension was larger in all HRJB specimens; the anteroposterior dimension was larger only in dehiscent HRJB. So, they deduced the HRJB grows first in the mediolateral dimension and then in the anteroposterior one. Further, there was no significant difference, in terms of width, between HRJB and DHRJB. So, the dehiscence depends on JB dimensions and relationships; this latter depends on mastoid pneumatization and temporal development [2]. HRJB and JBD may erode several structures, such as the cochlea, VA, PSCC, IAC, and tympanic cavity [2, 5, 10].
The literature reports an obvious divergence between studies on the prevalence of HRJB, JBD, and DHRJB. In their series of 2299 temporal CT, Woo et al. have considered the JB as high riding if it reaches any point between the RW and the IAC. Thus, they reported 9.5% and 2.6% respective prevalence of HRJB and DHRJB. Atmaca et al. reported that, of 1010 Turkish participants who underwent temporal CT, 15.2% had an HRJB and 7.5% had a DHRJB; they used the IAC as a definition landmark [10]. Friedmann et al. evaluated 100 temporal CTs and 1579 temporal bone specimens, considering the same definition as Atmaca et al. and they found an 8.2% prevalence in the histological sample and an 8.5% prevalence in the radiological sample. Last, the prevalence of DHRJB was 2.8% in CTs and 3% in temporal specimens; the prevalence of JBD was 1.3% [2]. Zuniga et al. studied, retrospectively, bilateral temporal CT of 229 Mexican patients between two months and 91 years old. They used the basal turn of the cochlea as a landmark to define the HRJB. The prevalences of HRJB and DHRJB were 38.4% and 1.3%, more often in women. Further, the results of their across-age prevalence evaluation matched those of the Friedmann study. Wang et al. reported that HRJB existed in 14.5% of 4539 healthy Chinese participants who underwent a head MRI; 1.5% of them had a bilateral HRJB. They used the same definition as Friedmann [9]. Aksoy et al. reported the same prevalence of bilateral HRJB in 194 children [2]. Shaikh et al. reported, according to Chen et al. and Huang et al., that DHRJB occurred in 0.5–1.7% [7]. To summarize, we agree with Wang et al. [9] that as long as consistency in the definition of HRJB lacks, the prevalence will be always imprecise. Otherwise, the sample size, the study design, the research techniques, and other factors could influence the results [9].
HRJB can be asymptomatic or provokes several symptoms, such as vertigo, dizziness, headaches, ear fullness, conductive or sensorineural hearing loss, and pulsatile tinnitus [5, 9, 10]. Conductive hearing loss involves HRJB protrusion against the eardrum, and obstruction of the RW. When it is in direct contact with the auditory ossicle chain, the HRJB impedes its mobility. This will block the sound transmission through the tympano-ossicular chain. A JB protruding in the inner ear through the RW or compressing the vestibulocochlear nerve may generate sensorineural hearing loss and tinnitus [9]. The relation between HRJB and MD as a hypothesis to explain HRJB-associated vertigo is still controversial [4]. The literature reports that HRJB provokes MD-like symptoms [10]; the association between HRJB-related VA dehiscence and EH seems possible [2]. As reported by some authors, HRJB prevents endolymphatic resorbing [9] and subsequently leads to EH, the substratum of MD. In contrast, Haginamori et al. reported, in their series of 197 temporal bones, that 2% of HRJB specimens had VA dehiscence; no EH was present. However, they reported « hypoplastic ES running through a hypoplastic VA » as a histological finding, resulting probably from JB-related ES compression. In previous work, Friedmann et al. studied 30 patients with DJB confirmed in HRCT, of which 25 had VA dehiscence and two-thirds were symptomatic; only two patients had EH. They studied simultaneously 1579 temporal bone specimens, of which 41 had VA dehiscence, and reported just two cases of associated EH [2]. In summary, the studies conflict about the association between EH and HRJB; it is early to admit the role of HRJB in MD. The HRJB appears in the otoscopic exam as a bluish mass behind the posterior inferior quadrant of the eardrum. All actions which increase the pressure on the JB, such as the Valsalva maneuver, ipsilateral IJV compression, and supine position, will distend it and facilitate the exam [4, 5, 7]. When HRJB manifests as a bluish mass, the differential diagnosis involves vascular conditions which appear the same; it includes the internal carotid artery aberrance or diverticulum, eardrum phlebectasia, and hemangioma. Other tumors may be similar: blue-domed mucosal cyst, paraganglioma, aural polyp, and extramedullary hematopoiesis [7]. It is possible to confuse HRJB with other vascular conditions such as glomus tympanicum or cholesterol granuloma; a well-corticate HRJB may look like a cholesteatoma or neoplasm [6]. However, a negative otoscopic exam does not exclude the diagnosis, since the JB may fluctuate in size from one examination to another [4]. In addition, an opacified eardrum, as in chronic middle ear disease, may hide the mass [7]. Likewise, the JBD does not, classically, protrude in the tympanic cavity and consequently is still invisible [5]; its diagnosis is often incidental. The HRCT is the gold standard to evaluate the HRJB and to diagnose the JBD; this latter appears as an expansion of the JB extending, commonly, upward and inside the petrosal bone [5]. As HRJB may be asymptomatic, and therefore unnoticed, an inadvertent surgical injury may lead to a profuse hemorrhage [7]. Thus, an accurate CT or angiography evaluation becomes an obligation [10]. Manjila and Semaan proposed a very helpful classification of the HRJB based on the HRCT (Table 1). It allows the surgeons to foresee with precision the potential risk of bleeding during surgery [5].
Although it does not prohibit ear surgery [5], HRJB represents a potential danger because of eventual hemorrhagic and air embolism complications [9, 10]. These events may occur if the JB is below the tympanic annulus, during the removal of osteomyelitis bone, keratin from the EAC, or tumors. It may occur too during the transcanal decompressing of the FN [4]. In addition, the surgeon must be careful during stapedectomy or tympanoplasty, when elevating the tympanomeatal flap [4]; he must follow the fibrous annulus and never attempt a biopsy [6]. If the HRJB is above, the injury may occur during the translabyrinthine approach or IAC surgery. During mastoid or labyrinthine surgery, a backward HRJB may disturb the intervention [4]. The surgeons can prepare the surgical procedure and estimate its result using Manjila and Semaan classification, which offers a good compromise between safety and efficiency. In HRJB type I and II of Manjila, the translabyrinthine approach is better for SS and JB skeletonization since it improves their exposure. For the same approach, a type III or IV of Manjila hinders exposure. The retrosigmoid approach is better to reach the cerebellopontine angle but is still risky during IAC exposure [5]. In MD patients with such a type, we must verify an obliteration of the VA with EH. In this condition, the VA separates the ES from the rest of the labyrinthine fluid space; the shunting/decompression of the ES will fail [4]. Prasad et al. proposed another classification of the HRJB based on surgical observation of 49 HRJB (Table 1). In grades III to V, the HRJB hampers the RW testing reflex. The surgeon, in obligation to displace the JB, should push it as well as remove the covering epithelium, if present, with utmost care [6]. In the same way, a retro-labyrinthine HRJB blocks access to the IAC and limits the exposure of the cochlear aqueduct [6, 9]. In such a case, a translabyrinthine approach is impossible [6]. There are various treatment options for an HRJB, usually applied to symptomatic HRJB. First, we can use medical procedures such as labyrinthine sedation and control of systemic hypertension [5]. If the HRJB provokes severe symptoms, such as annoying tinnitus, intensive vertigo, or progressive hearing loss, surgery may be the choice. As proposed by Buckwalter et al., we can ligate the IJV when tinnitus is debilitating [5, 7]. Despite its successful outcomes, such a procedure exposes vital vascular and neural structures of the neck to significant risk [7]. In addition, this ligation may disrupt the venous flow; thus, it leads to idiopathic intracranial hypertension [5]. Next, the literature reports an alternative for surgery, which is endovascular access. The therapist either deploys a stent or coils it [5, 7]. Trivelato et al. reported a case of pulsatile tinnitus on JBD treated with a stent and selective embolization with good outcomes. Mortimer et al. used a transfemoral approach to treat two JBDs at two separate times, the first with stent and coils, the second with coils only; the patient became finally asymptomatic. However, this method has a high rate of intracranial hypertension and ischemic stroke; thrombosis of the stent may occur such as reported by Mortimer et al. for the first JBD at the five-month follow-up control [5]. For a DHRJB, literature proposed several surgical techniques which target putting back the JB in place and reconstructing the covering bone. In the first technique, the surgeon performs a mastoidectomy and applies a bone wax to cover the JB; the FN, middle ear, and dura mater are at risk of injury during such a procedure [5]. Glasscock et al. treated two cases of JBD in the tympanic cavity, causing hearing loss. They used a piece of mastoid bone as a graft to cover the JB, reinstated in place. Despite the success of the procedure, the patients did not recover their auditive function; the authors did not recommend this technique. El-Begermy et al. used bone dust, perichondrium, and tragal cartilage in multiple layers to rebuild the bony dehiscence on a series of seven patients complaining of tinnitus; five of them had symptoms relief, and one had intracranial hypertension [7].
| Classification | Types | Features | |
|---|---|---|---|
| Radiological classification: Manjila and Semaan [5] | Type I | No identified JB | |
| Type II | Type II a | The JB is below the inferior margin of the PSCC without dehiscence in the middle ear cavity | |
| Type II b | The JB is below the inferior margin of the PSCC with dehiscence in the middle ear cavity | ||
| Type III | Type III a | JB is between the inferior margin of PSCC and the inferior margin of IAC without dehiscence | |
| Type III b | JB is between the inferior margin of PSCC and the inferior margin of IAC; the JB is dehiscent in the IAC | ||
| Type IV | Type IV a | JB is above the inferior margin of IAC without dehiscence | |
| Type IV b | JB is above the inferior margin of IAC; the JB is dehiscent in the IAC | ||
| Type V | Combination of dehiscences | ||
| Surgical classification: Prasad et Bahavas [6] | Grade 1 (81%) | HRJB up to the level of the tympanic annulus | |
| Grade 2 (11%) | HRJB up to the lower end of the inferior margin of the round window | ||
| Grade 3 (6%) | The HRJB obliterates completely the RW | ||
| Grade 4 (6%) | The HRJB lies between the RW and the stapes | ||
| Grade 5 (2%) | The HRJB is abutting the stapes arch | ||
In our case, we encountered a unique anatomical presentation of the JB during the diagnosis and assessment of our patient’s disorders. First, we objectified a bilateral HRJB associated with a right JBD; as reported above, they are rare entities. Then, the literature includes only one case of JBD-mastoid dehiscence in a 30-year-old man, reported by Fukumoto et al. In our case, both HRJB and JBD were dehiscent in the mastoid cavity. Next, the new is the dehiscence of both right JB and JBD in Trautmann’s triangle. To the best of our knowledge, there is no similar case reported before. Trautmann’s triangle is a surgical triangle between the JB, sinodural angle, and PSCC. This triangle allows access to the cerebellopontine angle and cranial nerves V, VII, VIII, IX, and X during the retro-labyrinthine presigmoid approach. This approach served for vestibular neurectomy to treat vertigo and to resect lesions ventral to the brainstem, such as petroclival meningioma. Surgeons used it currently to shunt the ES in MD [8]. The dehiscence in Trautmann’s triangle with imminent herniation of the JB may disturb such surgical procedures.
BT: Basal turn of the cochlea DHRJB: Dehiscent high-riding jugular bulb
DJB: Dehiscent jugular bulb DJBD: Dehiscent jugular bulb diverticulum
EAC: External auditory canal EH: Endolymphatic hydrops
ES: Endolymphatic sac FN: Facial nerve
HRCT: High-resolution computed tomography HRJB: High-riding jugular bulb
IAC: Internal auditory canal IJV: Internal jugular vein
JB: Jugular bulb JBD: Jugular bulb diverticulum
JD: Jugular diverticulum MD: Meniere’s disease
PSCC: Posterior semicircular canal RW: Round window
SS: Sigmoid sinus VA: Vestibular aqueduct
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Authors contribution
MA Alnafie: Project development, Data collection, Management and analysis, Manuscript editing and writing
Ethical approval : This case report has been performed in accordance with the ethical standards as laid down in the Declaration of Helsinki and the ethical standards of the ethical and deontological committee of the University of Oran 1 Ahmed Ben Bella
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