Table 1: Summary of articles included in the systematic review

Authors / Reported diagnoses or procedure / No. of Patients / Reported events / Duration of study / Cost metric / Cost of complications / Overall Costs
Linville et al., 1999 [37] /
  • Adult spinal deformity
  • Spinal fusion surgery
/ 44 /
  • Complications, n=10
  • Revision, n=26
/ 6 months / Direct costs / Not reported /
  • Revision vs. primary surgery - $86,673 vs. $74,454

Tosteson et al., 2008[23] /
  • Intervertebral disc herniation
  • Open laminectomy/laminectomy with removal of the herniation
/ 120 /
  • Complications, n=22
  • Repeat surgeries, n=63
/ 2 years / Direct & Indirect costs /
  • Mean surgery costs to treat 22 complications - $19,063
  • Mean cost to treat 63 repeat surgeries - $28,019
/ 1. Mean treatment costs at the level of each individual
  • Total direct cost - $20,237
  • Total indirect cost - $7,089
  • Total costs - $27,241

Patil et al., 2008[29] /
  • Idiopathic scoliosis
  • Spinal fusion surgery
/ 16,311 /
  • Complications, n=4,095
  • Adverse outcomes, n=3,321
/ 9 years / Direct costs /
  • Mean total hospital charges in patient with complications - $57,015
/ 1. Mean total hospital charges/complication:
  • 0 -$51,622
  • 1 -$68,100
  • 2 -$1,03,165
  • 3 -$1,18,842

Ambrossi et al., 2009[33] /
  • Lumbar disc herniation
  • Revision discectomy
/ 156 /
  • Complications, n=10
  • Revision surgery, n=11
/ 1, 3, 6, and 12 months / Direct costs /
  • Mean cost per patient with recurrent disc herniation - $26,593
/
  • Mean total cost of revision surgery -$39,863
  • Total cost to treat 11 patients for recurrent disc herniation-$406,550
  • Estimated cost of recurrent disc herniation - $289,797/100 cases of first-time lumbar discectomy

McGirt et al., 2011[25] /
  • Lumbar spondylotic disease, disc degeneration, or spondylolisthesis
  • 1- or 2-level Minimally Invasive or Open spinal fusion surgery
/ 5,170 /
  • Complications, n=292
/ 8 weeks / Direct costs /
  • Average direct cost to treat one SSI - $15,817
/
  • Total direct cost to treat 292 SSIs - $4,618,812

Parker et al., 2011[38] /
  • Degenerative disc disease or Grade I-II spondylolithesis
  • Open TILF
/ 120 / Complication, n=11 / Not reported / Direct costs / Not reported /
  • Mean cost for 6 patients with SSI-$29,110

Adogwa et al., 2012[34] / Revision neural decompression (laminectomy/foraminotomy) and instrumented fusion for recurrent same-level stenosis / 42 /
  • Complications, n=5
  • Revision surgeries, n=42
/ 2 years / Direct costs /
  1. Mean total 2-year costs:
  • Direct costs-$30,808+$5,487
  • Indirect costs-18,623+9098
2. Median number of months of missed work-6.5(IQR 5-10) months /
  • Mean total 2-year cost of revision surgery-$49,431+$7,583

Whitmore et al., 2012[26] / Any spine surgery / 226 /
  • Complications, n=129
  • Major, n=49
  • Minor, n=80
/ 1 month / Direct - hospital costs /
  1. Additional increase in cost/case
  • Pulmonary - $7,233
  • Instrument malposition - $6,968
  • New neurological deficit – $4,537
2. Wound infection - $4,067 / 1. Average cost of care to society for cases:
  • With vs. without complications-$13,518.35
  • Major vs. minor-$13,714.88
2. Minor vs. without complication-$8308.82
Parker et al., 2012[39] /
  • Prior lumbar fusion with radiographic evidence of ASD, pseudoarthrosis, or same-level stenosis.
  • Revision instrumented lumbar fusion
/ 150 /
  • Complications, n=47
  • Revision surgery, n=150
/ 2 years / Direct costs /
  • Presence of SSIs was associated with a 2.65 increase in 2-year total costs
/
  • The mean 2-year direct cost for undergoing revision surgeries - $32,915+$8,344

Hellsten et al., 2013[22] /
  • Any spine surgery
/ 1,815 /
  • Adverse events, n=316
  • Revision surgeries, n=46
/ 4 years / Direct costs / 1. Mean cost per discharge for cases with AE vs case without AE -$54,225.61 vs. $23,465.43
2. Incremental dollar cost for each case of AE:
  • AE Grade 1 =$4,224
  • AE Grade 2 =$23,500
  • AE Grade 3 =$147,285
  • AE Grade 4 =$121,366
/
  1. Additional increase in incremental costs:
  • Grade 1: $0.66 million
  • Grade 2: $2.96 million
  • Grade 3: $4.27 million
  • Grade 4: $0.49 million
2. Across all AE grades, total incremental cost to the hospital was $8.38 million or $2.10 million/annum
McCarthy et al., 2013[18] /
  • Adult spinal deformity
/ 325 /
  • Revision surgery, n=120
/ 2 years / Direct costs /
  • Average direct cost of revision surgery - $67,220+$27,963
/ Not reported
Godil et al., 2013[27] /
  • Spine trauma undergoing posterior spinal fusion
/ 110 / Complications, n=7 / 4 to 86 weeks / Direct costs /
  • Mean total infection-related cost per patient - $33,705
  • Infection related cost per 100 spinal fusions was $438,165
/
  • Use of Vancomycin powder led to cost savings of $433,765 per 100 posterior spinal fusions

Nandyala et al., 2014[32] /
  • Cervical or lumbar decompression and/or fusion procedures
/ 278,866 / Complications, n=5402 / Not reported / Direct costs / 1. Average hospital costs in patients with durotomy vs. without durotomy:
  • Cervical-$23,407+$18,291 vs.12,609+$8,674
  • Lumbar - $20,731+17,601 vs. $18,818+15,904
/ 1. Additional increase in average total hospital costs due to presence of durotomy :
  • Cervical - $7,638
  • Lumbar - $2,412

Theologis et al., 2014[28] /
  • Adult thoracolumbar spinal deformity
/ 215 /
  • Complications, n=11
  • Revision surgeries,n=92
/ 68 months / Direct costs / 1. Average SSI cost/index case:
  • Control - $3224
  • Intervention - $780
2. Average cost per index operation:
  • Control-$63,287
  • Intervention - $69,686
3. Average cost of SSI treament/patient:
  • Control - $34,888
  • Intervention - $28,169
/ 1. Total direct costs in treating SSI:
  • Control - $206,326
  • Intervention - $112,677
2. Use of vancomycin powder resulted in cost savings of $244,402 per 100 thoracolumbar adult deformity procedures.
Hostin et al., 2015[30] / Adult spine deformity / 481 /
  • Complications, n=104
/ 2 years / Direct costs / 1. Average total costs of complications:
  • Pseudarthrosis - $76,695
  • Instrument Failure - $66,838
  • Junctional Failure - $42,766
  • Infection/Wound complication - $38,701
  • Neurological/radiculopathy - $29561
  • Medical average cost - $26,622
  • Pain complication - $20,947
  • Other complication - $18,261
/
  • Total cost per readmission due to complications averaged $43,171+ 42,666

Kuhns et al., 2015[24] /
  • Dorsal cervical fusion
/ 551 /
  • Complication, n=22
/ 5 months / Direct and indirect costs / 1. Additional hospital and surgical costs for postoperative wound infections averaged $7,062.
2. Direct Cost of treating Infection vs control cohort:
  • Postoperative costs-$5,200+$3,931 vs. $1,670+$1,298
  • Direct health care cost- $16,970+$4,375 vs. $7,658+$2,625
3. Indirect costs of treating infection vs control cohort:
  • $6,495+$4,769 vs. $2,756+$3,563
  • Average number of days missed from work-38 vs.15
/
  • Total adjusted hospital costs for the infection cohort vs. non-infection cohort - $21,778+$5,625 vs. $9159+$4,087

Daniels et al., 2016[31] /
  • Anterior cervical discectomy and fusion (ACDF)
  • Posterior lumbar interbody
fusion (PLIF)
Lumbar laminectomy (LL / 50,652 / Complications, n=665 / 3 months / Direct costs / 1. Median inpatient charges for patients with DVT compared to patients without DVT
  • ACDF - $313,536
  • PLIF - $284,121
  • LL - $222,455
2. Charges for patients with PE compared to patients without PE:
  • ACDF - $213,088
  • PLIF - $246,637
  • LL - $159,566
3. Charges for patients with SSI compared to patients without SSI:
  • ACDF - $172,967
  • PLIF - $385,753
  • LL - $196,112
/ 1. The median increase in total inpatient charges for patients with complications compared to those without complications was:
  • DVT - 2.0 to 4.3 times greater
  • PE – 1.7 to 3.1 times greater
  • SSI – 2.4 to 3.8 times greater