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The Impact of Hemipelvectomy and Hip Disarticulation on Lumbar Bone and Muscle Quality
Hannah A Levy1, Caden Messer1, Marisa N Ulrich1
1Department of Orthopedic Surgery, Mayo Clinic, Rochester, MN.
Study Design:
Retrospective.
Objective:
To examine the long-term perioperative changes in lumbar bone quality, paraspinal muscle size and fat content, and facet degeneration after hemipelvectomy (HP) and hip disarticulation (HD).
Summary Of Background Data:
Emerging evidence shows that transfemoral (TFA) and transtibial (TTA) amputations may accelerate lumbar modic changes and precipitate axial back pain. TFA and TTA amputation studies demonstrate that the severity of postamputation lower back pain is associated with the amputation type (TFA > TTA) and the degree of alteration in lumbopelvic kinematics.
Methods:
All patients who underwent HP or HD for malignancy or infection at an academic center between 2003 and 2022 were retrospectively identified. Preoperative to postoperative changes in multifidus, erector spinae, quadratus lumborum, and psoas cross-sectional area (CSA), and Hounsfield units (HU) were calculated on CT for the amputated and contralateral side at the level of the L3-4 disc space. Paired univariate analysis was utilized to compare preoperative and postoperative outcomes.
Results:
A total of 16 patients (8 HP, 8 HD) met the inclusion/exclusion criteria. The preoperative to postoperative changes in HUs in the L1, L3, and L5 vertebral bodies were -27.0 (P=0.004), -51.5 (P=0.002), and -48.1 (P=0.001), respectively. The decrease in L1 HU was greater for prosthesis nonusers (user: -16.50, nonuser: -51.32, P=0.021). L5-S1 segment facet degeneration increased postoperatively (P=0.030, n=7 progressed). There were significant preoperative to postoperative changes in psoas CSA (preop: 1063.4, postop: 586.5, P=0.005) and psoas HU (preop: 50.95, postop: 33.55, P<0.001) on the amputated but not the contralateral side.
Conclusion:
Hind-quarter amputations were associated with decreased lumbar bone quality, progression of facet degeneration, and loss of amputated side psoas muscle tone. Daily prosthesis use was moderately protective for lumbar bone quality following amputation. HP but not HD was associated with postoperative loss of amputated side quadratus lumborum tone.
Level Of Evidence:
Level III.
