耳石症学说

1969年Schuknecht提出了嵴帽结石症学说。

1979年 Hall提出了管结石症学说。

Hall并没有否定嵴帽结石症学说，而是认为管结石症是嵴帽结石症学说的重要补充，只是耳石可以位于半规管长臂侧。

1980年Epley对耳石症的阐述，认为移位的耳石，密度超过内淋巴液，可以位于椭圆囊内，黏附于壶腹帽上，飘浮在半规管内，通过撞击嵴帽或者内淋巴液流动造成嵴帽运动。

Epley对29例Dix-Hallpike试验阳性患者，调查了平卧躺下，坐起，前俯，转头，加速减速，直立活动，垂直震荡等动作诱发眩晕情况，对11例患者切除支配后半规管壶腹嵴的神经（单神经切除术），9例患者症状缓解，证实BPPV和后半规管壶腹嵴功能有关。

Epley图示解释了不同体位诱发眩晕，其对后半规管壶腹嵴空间方向的描述是正确的。 Epley还论证了相同质量的结石，管石的效应超过嵴石的效应[1]。

参考文献：

Epley J M. New dimensions of benign paroxysmal positional vertigo[J]. Otolaryngology & Head & Neck Surgery, 1980, 88(5):599.

Epley J M. Positional vertigo related to semicircular canalithiasis [J]. Otolaryngology - Head and Neck Surgery, 1995, 112(1):154-161.

术语问题

cupulolithiasis：嵴帽结石症

canalithiasis：管结石症

壶腹嵴顶耳石症 半规管耳石症

耳石位置

1999年Buckingham使用颞骨不同平面切片，用米粒模拟耳石，研究了耳石症理论并探讨了耳石可能位置。

文章中提到，结石复位后容易沉降于后半规管壶腹嵴椭圆囊侧。

论文中提到结石位于半规管侧别：utriculofugal cupula of the posterior semicircular canal；utriculopetal cupula of the posterior semicircular canal

2010年Oas提出“New terminology is required to differentiate short-arm from long-arm canalolithiasis.”

However, the terminology begins to break down when we must specify where the otoconia exist within the involved semicircular canal system. For instance, if otoconia are in the short-arm part of the semicircular canal most adjacent to the utricular sac (the three remaining vulnerable orifices identified before), what are we going to call this? By our earlier definition, canalolithiasis is not precise enough to differentiate such cases; thus, we must specify either the short arm or the long arm when defining canalolithiasis clinically. Clinically, short-arm PSC canalolithiasis is less common than long-arm PSC canalolithiasis. I estimate its incidence around 25–33% of PSC canalolithiasis cases.

My own data based on VNG recordings suggests that two pathological conditions can often be differentiated by the characteristics of the positioning nystagmus observed in the head-hanging position after the paroxysmal part of the nystagmus has ended. Short-arm canalolithiasis has a persistent ipsidirectional torsional nystagmus, while long-arm canalolithiasis has a small transient contradirectional nystagmus.

2011年buki报道：

Seven of the 20 patients had trunk oscillations during the act of sitting up and for a short time immediately afterwards. Based on their findings, the authors propose a new type of BPPV, the so-called Type 2 BPPV (typical complaints of BPPV, no nystagmus in Dix–Hallpike positions but short vertigo spell while sitting up), which may be the result of chronic canalolithiasis within the short arm of a posterior canal. Furthermore, the authors suggest that Type 2 BPPV, which could be identical to sBPPV or constitute a major subgroup of it, occurs frequently among patients with vertigo. For therapy, the authors recommend repetitive sit-ups from the Dix–Hallpike positions to liberate the short arm of the posterior canal from canaloliths.

For therapy, the authors recommend repetitive sit-ups from the Dix–Hallpike positions to liberate the short arm of the posterior canal from  canaloliths.

2011年Taura报道4例可疑shot-arm psc-BPPV Benign paroxysmal positional vertigo (BPPV) is one of the most common causes of vertigo, and the posterior canal is the most frequently involved structure because of its anatomical position. In the majority of posterior canal BPPV cases, a particle-repositioning maneuver, such as the Epley maneuver, is effective, since the otoconia is thought to be located in the long arm of the posterior canal. However, Oas et al. has proposed a subtype of posterior canal BPPV, known as short-arm type BPPV, in which the otoconia is assumed to be located not in the long arm of the posterior canal, but in the short arm (between the utricle and the cupula). Here, we present four cases of BPPV that presumably involve the short-arm type posterior canal. The duration of nystagmus was extended in all four cases when the head was moved as in the Dix Halllpike test. Furthermore, when the head was moved back to a sitting position, the reversal of nystagmus was not or very faintly observed. As a treatment, the Epley maneuver was initially attempted, but this treatment was not effective. However, vibration methods (involving the application of vibration to the mastoid process of the affected ear with the intact ear positioned downwards) were effective in all four cases.

2013年日本重野报道39例后半规管短臂侧管结石症，表现诱发试验呈持续垂直扭转眼震。 When a 3D model of the human temporal bone is considered in the supine position, the direction of the pc-short-arm is perpendicular to the direction of gravity whereas in the sitting position, the direction of the pc-short-arm is in line with the direction of gravity. In order for the otoconias to return from the pc-short-arm into the utricle, it appears to be important to place the head in a position 180 degrees opposite to the sitting position.

2015年buki报道：

One should keep in mind that, when dislodged from the utricular macula, freely moving otoconia may move into any canal or be attached to any cupula of the ampullae, thereby causing canalolithiasis and/or cupulolithiasis of the individual canal (for a review see Parnes et al., 2003)

debris should always be in the most inferior part of the compartment in the starting position; then, in the provocative position it sinks into the most inferior part of the compartment. Therefore, debris may be in the vestibulum, short arm, long arm of the canal and be attached to the cupulae

However, apparently there is another, more latent, more chronic variant, when patients have typical BPPV symptoms (short vertigo when bending forward, lying down, sitting up or turning over in bed) but no nystagmus is evoked by Dix-Hallpike and supine roll maneuvers. Until now, this was called “subjective BPPV” and it has not been characterized. In an attempt to explain this, Büki et al. coined the term “type 2 BPPV” [9]. After “short arm” canalolithiasis had been already suggested by Oas back in 2001 [24], this variant was also hypothetically contributed to freely moving debris in the short arm of posterior canal.

As a diagnostic criterion, the unilateral sitting-up vertigo/body sway was suggested. This is felt/shown by the patients during sitting up from the Dix-Hallpike position, on one side, but not from the other.

they may gravitate toward the most posterior part of the utriculus, the ampulla of the posterior canal. Then, depending on their behavior (freely moving or sticking to the cupula) and the precise position of the posterior ampulla (which varies [6]), either no nystagmus or a slow downbeat nystagmus should ensue when the patient is positioned from sitting to a Dix-Hallpike position.

Because debris is moving out from the short arm, no nystagmus is elicited in Dix-Hallpike position but sitting up vertigo/body sway either in the diagonal vertical planes corresponding right anterior- left posterior or left anterior right posterior semicircular canals. Both in posterior canal cupulolithiasis and posterior short arm canalolithiasis a strong vegetative reaction (nausea, sweating) has been noted after repeated positioning which is out of proportion considering the missing nystagmus [9].

2015年Ichimura报道 Introduction: In positional vertigo, spontaneous reversal of the initial positional nystagmus (the secondary phase nystagmus) is clinically rare without head position changes. We present herein a case of positional vertigo with the secondary phase nystagmus monitored and video-recorded using an infrared CCD camera.
　Patient: A 65-year-old woman visited our otorhinolaryngological clinic with rotatory positional vertigo. At the initial visit, upbeat-torsional (counterclockwise) nystagmus induced by the head positional test was observed for>70s, with a latency of 2s; furthermore, the reversal of nystagmus was not observed when the head was moved back to the sitting position. Three days later, downbeat-torsional (clockwise) nystagmus induced by the head positional test was observed for 19s with a latency of 3s, and it was followed by reversal of initial positional nystagmus for 75s without head position changes.
　Conclusion: The duration of positional nystagmus was>70s, and the reversal of nystagmus was not observed when the head was moved back to the sitting position. Therefore, we speculated that positional vertigo presumably involved canalolithiasis within the short-arm of the posterior canal. Further, we speculated that the secondary phase nystagmus was presumably due to the coexistence of long-arm type anterior canalolithiasis and short-arm type posterior canalolithiasis.

分析：

使用切面图片进行解剖学观察，其解剖位置的准确性值得怀疑。 论文中提到后半规管短臂侧结石会刺激壶腹嵴引起耳石症症状。

参考： [2] Buckingham R A. Anatomical and theoretical observations on otolith repositioning for benign paroxysmal positional vertigo[J]. Laryngoscope, 1999, 109(5):717-22.

客观依据

1992年Parnes报道2例BPPV患者行半规管阻塞手术发现后半规管内淋巴液内游离耳石。 但在非BPPV手术患者也可以发现内淋巴液内游离耳石。为此，1997年Welling比较分析了73例非BPPV患者和26例BPPV半规管阻塞手术手术患者后半规管内淋巴液内耳石发现情况，同时显微镜观察了70例非BPPV患者颞骨切片膜迷路内耳石发现情况，结果73例非BPPV患者无一发现膜迷路内耳石，26例BPPV患者中有8例发现游离耳石，71例颞骨检查中有31例没有明显死后改变的无一发现壶腹嵴结石和管结石。

参考文献：

Parnes L S, Mcclure J A. Free‐Floating endolymph particles: A new operative finding during posterior semicircular canal occlusion[J]. Laryngoscope, 1992, 102(9):988-92.

Kveton J F, Kashgarian M. Particulate matter within the membranous labyrinth: pathologic or normal?[J]. Otology & Neurotology, 1994, 15(2):173-176.

[3] Welling D B, Parnes L S, O'Brien B, et al. Particulate matter in the posterior semicircular canal.[J]. Laryngoscope, 1997, 107(1):90-94.