Clinical Trial: Subclinical Propionibacterium Acnes Infection Estimation in the Intervertebral Disc (SPInE-ID)

Study Status: Not yet recruiting
Recruit Status: Not yet recruiting
Study Type: Observational

Official Title: Subclinical Propionibacterium Acnes Infection Estimation in the Intervertebral Disc (SPInE-ID): a Prospective Cohort

Brief Summary:

Subclinical infection of the intervertebral disc after lumbar disc herniation surgery has been correlated to chronic low back pain and vertebral endplate changes. The most commonly reported agent is Propionibacterium acnes. However, the real incidence is unclear, as it has been reported in some series ranging from 3.7% to 46%. Recently, a systematic review concluded that there is a relationship between P. acnes and endplate changes, but, there are so far no studies to verify whether the reported presence of that pathogen in the intervertebral discs is due to local infection or whether intraoperative contamination occurred during the collection of samples.

Thus, the main objective of this study is to estimate the incidence of subclinical infection in patients surgically treated for lumbar disc herniation.

To this end, a prospective cohort study will be conducted with a minimum of 95 patients between 18 and 65 years of age who have been submitted to surgery after failure of conservative treatment. The extruded disc will be removed and cultured for bacterial identification. As controls, the ligamentum flavum and the multifidus muscle, taken respectively before and after removal of the herniated fragment will also be cultured. Patients will be followed-up for a year and MRI will be done at the end of this period.

Detailed Summary:

INTRODUCTION Low back pain is a frequent condition in the population, as well as vertebral endplates abnormalities, described by Modic et al.(1,2), that affect up to 6% of the general population, and, up to 46% of patients with low back pain(3). Modic type I changes are described as vertebral bone marrow edema related to acute low back pain(4). When Modic changes are detected, chances of one presenting unspecific low back pain are 4.5 times higher(1,2).

Subclinical infection caused by low-virulence pathogen can possibly lead to vertebral endplate abnormalities, detected in magnetic resonance imaging (MRI) studies, and differentiation between infection and Modic changes may be difficult(5,6). Subclinical infection can also be associated with increasing low back pain(7). Albert et al(8) reported 61 patients who had undergone surgical treatment for lumbar disc herniation where 46% of cases had a positive culture. The same authors also reported that 80% of patients with a positive culture for anaerobic pathogens presented Modic type I changes at the adjacent vertebra after a two-year follow-up, against 44% of patients with negative culture. Some studies demonstrated the presence of low-virulence pathogens in intervertebral disc tissue cultures(6-10), most commonly reported to Propionibacterium acnes.

Chronic low back pain and Modic type I changes have been treated with antibiotics for up to 100 days with superior outcomes compared to sham treatment(7). Patients were treated with amoxicillin/clavulanate (500mg/125mg)(7) based on the study where sciatica is associated with Propionibacterium acnes(8).

However, Carricajo et al(11) suggest that the presence of P. acnes in the intervertebral discs is due to either external surgical or laboratory contamination. These authors detected
Sponsor: Hospital Israelita Albert Einstein

Current Primary Outcome: Rate of Intervertebral Disc Infection [ Time Frame: through study completion, an average of 1 year ]

Original Primary Outcome: Same as current

Current Secondary Outcome:

• Low Back Pain [ Time Frame: At time of patient recruitment and 1, 3, 6 and 12 months after surgical procedure ]
  Intensity of low back pain and limitation for daily activities of patients with and without infection will be analyzed through the Numeric Rating Score (NRS) system applied at time of patient recruitment and 1, 3, 6 and 12 months after surgical procedure. Minimal clinically important difference will be considered as an increase of 30% of baseline lumbar pain at first postoperative month, due to possible bias of postoperative pain due to surgical manipulation as well as pain due to the disc herniation itself.
• Quality of Life [ Time Frame: At timing of patient recruitment, and 1, 3, 6 and 12 months after surgery. ]
  Quality of life at the end of one year for both infected and uninfected groups, with and without Modic changes, will be analyzed through the validated Portuguese version of the EuroQol (EQ-5D) questionnaire. This measurement tool will be applied at timing of patient recruitment, and 1, 3, 6 and 12 months after surgery.
• Function [ Time Frame: At time of recruitment and 1, 3, 6 and 12 months after surgery. ]
  Function will be quantified through the Portuguese version of the Oswestry Disability Index (ODI) for lumbar pain that will be applied at time of recruitment and 1, 3, 6 and 12 months after surgery.
• Modic incidence [ Time Frame: 1 year after surgery ]

  Insurgent Modic changes in patients will be analyzed one year after surgery, as well as its relationship with presence or absence of infection.

  Incidence of Modic (IM) changes will be calculated for the infection group (IM infec) and for the total group (IM total) as follows:

  (number of Modic changes in infected IM infec = patients after 1 year) (total number of infections)

  IM total = number of Modic changes at final 1 year follow-up total number of patients

• Volume of Modic changes [ Time Frame: Preop and 12-month postop acquired MRI studies will be compared. ]
  Modic volume will be measured according to Wang et al(18). Three sagittal slices of the lumbar spine will be considered: midsagittal slice; left pedicle parasagittal slice; and right pedicle parasagittal slice. The parameters examined to quantify Modic changes will include measures of ratios of the region affected by Modic changes to the entire corresponding vertebral body, including maximal width ratio, maximal height ratio, and area ratio. Vertebral body changes will be classified accordingly to Modic changes type I, II, and III(1,2).
• Adverse effects [ Time Frame: Through study completion, an average of 1 year after inclusion ]
  Fail of surgical treatment (recurrence, instability, need for reoperation, etc.); need for additional physical therapy sessions; superficial infection; drainage; deep venous thrombosis; and, any other possible adverse event that may show up will be included as well.
• Imaging analysis of edema [ Time Frame: Preop and 12-month postop acquired MRI studies will be compared. ]
  Data will be collected for presence of vertebral or disc edema, and presence of disc hydration or not.
• Imaging analysis of disc degeneration [ Time Frame: Preop and 12-month postop acquired MRI studies will be compared. ]
  Disc degeneration will be collected as: normal; degeneration with height preservation; and, degeneration with loss of height. Presence of disc hydration or not.

Original Secondary Outcome: Same as current

Information By: Hospital Israelita Albert Einstein

Dates:
Date Received: May 15, 2017
Date Started: May 22, 2017
Date Completion: May 22, 2019
Last Updated: May 16, 2017
Last Verified: May 2017