Adjacent-level biomechanics after single versus multilevel cervical spine fusion

Laboratory investigation

View More View Less
  • 1 Departments of Orthopaedics and
  • | 2 Biomedical Engineering, University of Miami;
  • | 3 Max Biedermann Institute for Biomechanics at Mount Sinai Medical Center, Miami, Florida; and
  • | 4 Division of Spine Surgery, Naval Medical Center, Portsmouth, Virginia
Restricted access

Purchase Now

USD  $45.00

Spine - 1 year subscription bundle (Individuals Only)

USD  $376.00

JNS + Pediatrics + Spine - 1 year subscription bundle (Individuals Only)

USD  $612.00
Print or Print + Online

Object

Previous studies have demonstrated that patients with spinal fusion are at greater risk for adjacent-segment disease and require additional surgery. It has been postulated that excessive motion of a given motion segment unit (MSU) leads to an increased risk of disc degeneration. It is the authors' hypothesis that a greater increase in adjacent-segment motion will be observed following a 2-level versus a single-level anterior cervical discectomy and instrumented fusion (ACDF). Therefore, they undertook this study to determine the effect of single-level versus 2-level ACDF on the biomechanics of adjacent MSUs.

Methods

Ten fresh-frozen human cervical spines were used in this study. The specimens were potted at C-4 and T-1 and tested in flexion and extension. Range of motion (ROM) was 30° of flexion and 15° of extension at a maximum load of 50 N. The specimens were tested intact and then were randomized into 2 groups of 5 specimens each. Group 1 underwent a single-level ACDF at the C5–6 level first, and Group 2 underwent the procedure at the C6–7 level. After testing, both groups had the fusion extended to include the C5–7 levels, and the testing was repeated. Changes in overall ROM, stiffness, and segmental motion were calculated and statistically analyzed using a paired Student t-test.

Results

An increase in sagittal ROM of 31.30% above (p = 0.012) and 33.88% below (p = 0.066) the fused MSU was found comparing a 2-level with a 1-level ACDF. The overall stiffness of the entire spinal construct increased 37.34% (p = 0.051) in extension and 30.59% (p = 0.013) in flexion as the second fusion level was added. As expected, the overall sagittal ROM of the entire spinal construct decreased by 13.68% (p = 0.0014) with a 2-level compared with a 1-level fusion.

Conclusions

This study has shown that the biomechanics at adjacent levels to a cervical spine fusion are altered and that there is increased adjacent-segment motion at the levels above and below, after a 2-level compared with a 1-level ACDF.

Abbreviations used in this paper:

ACDF = anterior cervical discectomy and instrumented fusion; ASD = adjacent-segment disease; MSU = motion segment unit; PMMA = polymethylmethacrylate; ROM = range of motion.

Spine - 1 year subscription bundle (Individuals Only)

USD  $376.00

JNS + Pediatrics + Spine - 1 year subscription bundle (Individuals Only)

USD  $612.00
  • 1

    Baba H, , Furusawa N, , Imura S, , Kawahara N, , Tsuchiya H, & Tomita K: Late radiographic findings after anterior cervical fusion for spondylotic myeloradiculopathy. Spine (Phila Pa 1976) 18:21672173, 1993

    • Search Google Scholar
    • Export Citation
  • 2

    Brodke DS, & Zdeblick TA: Modified Smith-Robinson procedure for anterior cervical discectomy and fusion. Spine (Phila Pa 1976) 17:10 Suppl S427S430, 1992

    • Search Google Scholar
    • Export Citation
  • 3

    Clements DH, & O'Leary PF: Anterior cervical discectomy and fusion. Spine (Phila Pa 1976) 15:10231025, 1990

  • 4

    Cloward RB: The anterior approach for removal of ruptured cervical disks. J Neurosurg 15:602617, 1958

  • 5

    DePalma AF, , Rothman RH, , Lewinnek GE, & Canale ST: Anterior interbody fusion for severe cervical disc degeneration. Surg Gynecol Obstet 134:755758, 1972

    • Search Google Scholar
    • Export Citation
  • 6

    DiAngelo DJ, , Foley KT, , Morrow BR, , Schwab JS, , Song J, & German JW, et al.: In vitro biomechanics of cervical disc arthroplasty with the ProDisc-C total disc implant. Neurosurg Focus 17:3 E7, 2004

    • Search Google Scholar
    • Export Citation
  • 7

    DiAngelo DJ, , Foley KT, , Vossel KA, , Rampersaud YR, & Jansen TH: Anterior cervical plating reverses load transfer through multilevel strut-grafts. Spine (Phila Pa 1976) 25:783795, 2000

    • Search Google Scholar
    • Export Citation
  • 8

    Eck JC, , Humphreys SC, , Lim TH, , Jeong ST, , Kim JG, & Hodges SD, et al.: Biomechanical study on the effect of cervical spine fusion on adjacent-level intradiscal pressure and segmental motion. Spine (Phila Pa 1976) 27:24312434, 2002

    • Search Google Scholar
    • Export Citation
  • 9

    Emery SE, , Bolesta MJ, , Banks MA, & Jones PK: Robinson anterior cervical fusion comparison of the standard and modified techniques. Spine (Phila Pa 1976) 19:660663, 1994

    • Search Google Scholar
    • Export Citation
  • 10

    Goffin J, , van Loon J, , Van Calenbergh F, & Plets C: Long-term results after anterior cervical fusion and osteosynthetic stabilization for fractures and/or dislocations of the cervical spine. J Spinal Disord 8:500508, 1995

    • Search Google Scholar
    • Export Citation
  • 11

    Gore DR, & Sepic SB: Anterior cervical fusion for degenerated or protruded discs. A review of one hundred forty-six patients. Spine (Phila Pa 1976) 9:667671, 1984

    • Search Google Scholar
    • Export Citation
  • 12

    Gore DR, & Sepic SB: Anterior discectomy and fusion for painful cervical disc disease. A report of 50 patients with an average follow-up of 21 years. Spine (Phila Pa 1976) 23:20472051, 1998

    • Search Google Scholar
    • Export Citation
  • 13

    Gruss P, & Tannenbaum H: Stress exertion on adjacent segments after ventral cervical fusion. Arch Orthop Trauma Surg 101:283286, 1983

  • 14

    Herkowitz HN, , Kurz LT, & Overholt DP: Surgical management of cervical soft disc herniation. A comparison between the anterior and posterior approach. Spine (Phila Pa 1976) 15:10261030, 1990

    • Search Google Scholar
    • Export Citation
  • 15

    Hilibrand AS, , Carlson GD, , Palumbo MA, , Jones PK, & Bohlman HH: Radiculopathy and myelopathy at segments adjacent to the site of a previous anterior cervical arthrodesis. J Bone Joint Surg Am 81:519528, 1999

    • Search Google Scholar
    • Export Citation
  • 16

    Hilibrand AS, & Robbins M: Adjacent segment degeneration and adjacent segment disease: the consequence of spinal fusion?. Spine J 6 Suppl 4:190S1944S, 2004

    • Search Google Scholar
    • Export Citation
  • 17

    Humphreys SC, , Hodges SD, , Patwardhan A, , Eck JC, , Covington LA, & Sartori MC: The natural history of the cervical foramen in symptomatic and asymptomatic individuals aged 20–60 years as measured by magnetic resonance imaging. A descriptive approach. Spine (Phila Pa 1976) 23:21802184, 1998

    • Search Google Scholar
    • Export Citation
  • 18

    Hunter LY, , Braunstein EM, & Bailey RW: Radiographic changes following anterior cervical fusion. Spine (Phila Pa 1976) 5:399401, 1980

  • 19

    Jacobs B, , Krueger EG, & Leivy DM: Cervical spondylosis with radiculopathy. Results of anterior diskectomy and interbody fusion. JAMA 211:21352139, 1970

    • Search Google Scholar
    • Export Citation
  • 20

    Kolstad F, , Nygaard OP, & Leivseth G: Segmental motion adjacent to anterior cervical arthrodesis: a prospective study. Spine (Phila Pa 1976) 32:512517, 2007

    • Search Google Scholar
    • Export Citation
  • 21

    Kulkarni V, , Rajshekhar V, & Raghuram L: Accelerated spondylotic changes adjacent to the fused segment following central cervical corpectomy: magnetic resonance imaging study evidence. J Neurosurg 100:1 Suppl Spine 26, 2004

    • Search Google Scholar
    • Export Citation
  • 22

    Maiman DJ, , Kumaresan S, , Yoganandan N, & Pintar FA: Biomechanical effect of anterior cervical spine fusion on adjacent segments. Biomed Mater Eng 9:2738, 1999

    • Search Google Scholar
    • Export Citation
  • 23

    Matsunaga S, , Kabayama S, , Yamamoto T, , Yone K, , Sakou T, & Nakanishi K: Strain on intervertebral discs after anterior cervical decompression and fusion. Spine (Phila Pa 1976) 24:670675, 1999

    • Search Google Scholar
    • Export Citation
  • 24

    McGrory BJ, & Klassen RA: Arthrodesis of the cervical spine for fractures and dislocations in children and adolescents. A long-term follow-up study. J Bone Joint Surg Am 76:16061616, 1994

    • Search Google Scholar
    • Export Citation
  • 25

    Weinhoffer SL, , Guyer RD, , Herbert M, & Griffith SL: Intradiscal pressure measurements above an instrumented fusion. A cadaveric study. Spine (Phila Pa 1976) 20:526531, 1995

    • Search Google Scholar
    • Export Citation
  • 26

    White AA III, & Panjabi MM: Clinical Biomechanics of the Spine ed 2 Philadelphia, JB Lippincott, 1990. 98

  • 27

    Wigfield C, , Gill S, , Nelson R, , Langdon I, , Metcalf N, & Robertson J: Influence of an artificial cervical joint compared with fusion on adjacent-level motion in the treatment of degenerative cervical disc disease. J Neurosurg 96:1 Suppl 1721, 2002

    • Search Google Scholar
    • Export Citation
  • 28

    Yonenobu K, , Okada K, , Fuji T, , Fujiwara K, , Yamashita K, & Ono K: Causes of neurologic deterioration following surgical treatment of cervical myelopathy. Spine (Phila Pa 1976) 11:818823, 1986

    • Search Google Scholar
    • Export Citation

Metrics

All Time Past Year Past 30 Days
Abstract Views 675 161 9
Full Text Views 161 30 4
PDF Downloads 221 29 4
EPUB Downloads 0 0 0