Table 2.

Evidence summary table of the included cohort studies.

Authors	Year	Country	Mean Patient Age, yrs	Collar Indication	Collar Type	Reported Complications	Frequency of Complications	Mean Duration of Wear, Days
Moran et al.	2013	Australia	NR	Trauma	Aspen	Dysphagia Delirium LRTI Falls	4/8 (50%) 3/8 (38%) 5/8 (63%) 3/8 (38%)	NR d
Molinari et al.	2012	USA	84	Trauma	Miami J	Skin breakdown/ulceration	2/34 (6%)	84 (SD = 0)
Powers et al.	2006	USA	37.8	Trauma	Aspen	Skin breakdown/ulceration	33/484 (7%)	10.3 (SD = 11.4)
Molano et al.	2004	Spain	35.5	Trauma	NR	Skin breakdown/ulceration	22/92 (24%)	NR e
Nakanishi et al.	2019	Australia	81.9	Trauma	Philadelphia	Skin breakdown/ulceration HAP	11/90 (12%) 10/90 (11%)	NR
Hylton et al.	2016	UK	74	Trauma	Miami J	Psychosocial issues Skin breakdown/ulceration Skin erythema	6/51 (12%) 2/51 (4%) 10/51 (20%)	50.8
Ham et al.	2014	USA	43.7	Trauma	Various	Skin breakdown/ulceration	1/88 (1%)	3.5 (SD = 3.4)
Lewis et al.	2011	Australia	NR	Trauma	NR	Skin breakdown/ulceration	2/32 (6%)	NR f
Ackland et al.	2007	Australia	40.9 a	Trauma	Philadelphia	Skin breakdown/ulceration	27/299 (9%)	NR g
Karlberg et al.	1991	Sweden	26.8	Volunteer	Philadelphia	Impaired voluntary saccades	NR	5
Borders et al.	2018	USA	NR b	Trauma	NR	Dysphagia	104/113 (92%)	NR
Kalb et al.	2012	USA	51	Post-operative	NR	Dysphagia	NR c	NR
Iizuka et al.	2005	Japan	61.4	Post-operative	Philadelphia	Reduced cervical ROM	NR	42 h

^aMean male age = 38.2 yrs and mean female age = 43.5 yrs; assumption of equal proportion.

^bA majority (58%) of patients were under 65 yrs.

^cThere were 27 cases of dysphagia reported, with no significant increase in the hard collar group.

^dDuration of immobilisation = 2–12 weeks.

^eMedian day of ulcer detection = 7.

^fMean duration of all patients = 94.5 days.

^gMedian duration = 1 day (IQR = 2).

^hOne group 8 weeks in collar and the other 4 weeks in collar.

NR = not reported, LRTI = lower respiratory tract infection, HAP = hospital acquired pneumonia, ROM = range of motion