Table 3. Symptoms of primary spontaneous pneumomediastinum.

Study	Chest pain (%)	Dyspnea (%)	Neck pain (%)
Abolnik et al. 1991	88	60	48
Kaneki et al. 2000	100	58	70
Gerazounis et al. 2003	89	59	NR
Jougon et al. 2003	50	NR	25
Koullias et al. 2004	66	8	33
Weissberg & Weissberg 2004	82	45	NR
Campillo-Soto et al. 2005	27	22	14
Newcomb & Clarke 2005	89	67	11
Freixinet et al. 2005	78	41	NR
Macia et al. 2007	85	49	44
Mondello et al. 2007	100	88	44
Caceres et al. 2008	54	39	44
Al-Mufarrej et al. 2008	59	41	12
Takada et al. 2008	68	44	52
Perna et al. 2010	60	26	38
Ryoo 2012	51	14	23
Okada et al. 2014	75	40	10
Bakhos et al. 2014	65	51	29
Ebina et al. 2017	61	29	29
AVE ± std dev [n]	70.9%±19% [19]	43.4%±19.6% [18]	32.9%±17% [16]