Microbial SubstitutionNCT06502223
Impact of Gut Microbiota and Tryptophan Metabolites on Acute Pain in Lumbar Disc Herniation Surgery Patients
An observational study of Microbial Substitution and Tryptophan Metabolism Alterations, run by Dokuz Eylul University at 1 site in Turkey (Türkiye).
Trial summary
It is well-established that the gut microbiota plays a crucial role in various pain mechanisms, including visceral pain, inflammatory pain, headache, neuropathic pain, and opioid tolerance. Changes in the gut microbiome can alter pain perception. Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Microbial Substitution, Tryptophan Metabolism Alterations, Postoperative Pain, Acute
- What is being tested?
- Pain Perception in Patients Undergoing Lumbar Disc Herniation Surgery
- Type of treatment
- Surgery or procedure
- How many people
- 37 participants
- Where
- 1 siteTurkey (Türkiye)
- Study dates
- 12 Jan 2022to 15 Mar 2023
- How long will I take part?
- 1 Year
- Phase
- Observational
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- Adult, Older adult
Study population: Our study includes 37 lumbar disc herniation (LDH) surgeries performed in Dokuz Eylül University Faculty of Medicine Central Operating Rooms Brain and Nerve Surgery Hall. For the blood samples in which the investigators evaluated tryptophan metabolites; 2 mL of blood was used from the blood samples taken during routine surgery preparation for the patients and from the routine blood samples taken in the postoperative period, and no additional invasive intervention was performed. Concurrently with each blood draw, the patient's VAS score, the nature of the pain, and vital signs were recorded. Patient records, clinical histories, examination findings, and relevant laboratory results were electronically recorded.
Who may be able to join
- Patients undergoing lumbar disc herniation surgery at Dokuz Eylül University Hospital.
- Patients who have read and consented to the informed consent form for the study.
- Age 18 years or older.
- Surgery duration exceeding 2 hours.
Who cannot join
- Patients are unwilling to participate in the study.
- Surgery duration less than 2 hours.
- Patients under the age of 18.
- Patients with a history of abdominal surgery.
- Patients who received antibiotic therapy for intestinal pathology within the last 3 weeks.
- Patients with known abdominal pathologies suspected to alter the microbial flora (e.g., Crohn's disease, ulcerative colitis, celiac disease).
Trial locations and contacts
1 site in 1 country.
About this study
Official title: The Impact of Microbiota and Associated Blood Tryptophan Metabolites on Pain Perception in Patients Undergoing Lumbar Disc Herniation Surgery
It is well-established that the gut microbiota plays a crucial role in various pain mechanisms, including visceral pain, inflammatory pain, headache, neuropathic pain, and opioid tolerance. Changes in the gut microbiome can alter pain perception. In our study, The investigator investigated the effects of microbiota alterations and the associated tryptophan metabolites on acute pain using the Visual Analog Scale (VAS).
Read the detailed description
The study included patients aged 18 and above undergoing lumbar disc herniation surgery. Blood samples were collected preoperatively, at 8 hours, and at 24 hours postoperatively to analyze tryptophan metabolites (picolinic acid, 3- Hydroxykynurenine, anthranilic acid, kynurenine, quinolinic acid, kynurenic acid, xanthurenic acid). Concurrent VAS pain assessments were conducted, and correlations between tryptophan metabolites and VAS were evaluated.
- Being tested
- Pain Perception in Patients Undergoing Lumbar Disc Herniation Surgery
- Keywords
- Microbiota, Tryptophan, Picolinic Acid, Kynurenic Acid, Xanthurenic Acid, Quinolinic Acid, Acute Pain
- Medical subject headings
- Pain, Postoperative, Acute Pain
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Pain Perception in Patients Undergoing Lumbar Disc Herniation SurgeryProcedure or surgery
Also called Microbiota and Associated Blood Tryptophan Metabolites on
Analyze tryptophan metabolites (picolinic acid, 3- Hydroxykynurenine, anthranilic acid, kynurenine, quinolinic acid, kynurenic acid, xanthurenic acid). Concurrent VAS pain assessments were conducted, and correlations between tryptophan metabolites and VAS were evaluated.
What is being measured
The primary outcome is the main question the study is designed to answer.
Tryptophan metabolites (Picolinic Acid)
2 mL of blood was used from the blood samples taken during routine surgery preparation for the patients and from the routine blood samples taken in the postoperative period, and no additional invasive intervention was performed. The investigator elucidated the relationship between picolinic acid and its variations due to microbiota alterations with VAS in acute pain. Preoperative, postoperative, 8th-hour, and 24th-hour blood samples were routinely collected from patients, with 2 mL of sample material used each time. After the necessary centrifugation processes, the relevant laboratory team analyzed the picolinic acid levels (ng/mL).
Measured: Preoperative: Before surgery; Postoperative 8th-hour: 8 hours after surgery;Postoperative 24th-hour: 24 hours after surgery
Tryptophan metabolites (3-Hydroxykynurenine)
2 mL of blood was used from the blood samples taken during routine surgery preparation for the patients and from the routine blood samples taken in the postoperative period, and no additional invasive intervention was performed. The investigator elucidated the relationship between 3-Hydroxykynurenine and its variations due to microbiota alterations with VAS in acute pain. Preoperative, postoperative 8th-hour, and 24th-hour blood samples were routinely collected from patients, with 2 mL of sample material used each time. After the necessary centrifugation processes, the relevant laboratory team analyzed the 3-Hydroxykynurenine levels(ng/mL).
Measured: Preoperative: Before surgery; Postoperative 8th-hour: 8 hours after surgery;Postoperative 24th-hour: 24 hours after surgery
Tryptophan metabolites (Anthranilic Acid)
2 mL of blood was used from the blood samples taken during routine surgery preparation for the patients and from the routine blood samples taken in the postoperative period, and no additional invasive intervention was performed. The investigator elucidated the relationship between anthranilic acid and its variations due to microbiota alterations with VAS in acute pain. Preoperative, postoperative, 8th-hour, and 24th-hour blood samples were routinely collected from patients, with 2 mL of sample material used each time. The relevant laboratory team measured the anthranilic acid levels (ng/mL) following the required centrifugation procedures.
Measured: Preoperative: Before surgery; Postoperative 8th-hour: 8 hours after surgery;Postoperative 24th-hour: 24 hours after surgery
Tryptophan metabolites (Kynurenine)
2 mL of blood was used from the blood samples taken during routine surgery preparation for the patients and from the routine blood samples taken in the postoperative period, and no additional invasive intervention was performed. The investigator elucidated the relationship between kynurenine and its variations due to microbiota alterations with VAS in acute pain. Preoperative, postoperative, 8th-hour, and 24th-hour blood samples were routinely collected from patients, with 2 mL of sample material used each time. After the necessary centrifugation processes, the relevant laboratory team analyzed the kynurenine levels (ng/mL).
Measured: Preoperative: Before surgery; Postoperative 8th-hour: 8 hours after surgery;Postoperative 24th-hour: 24 hours after surgery
Tryptophan metabolites (Quinolinic Acid)
2 mL of blood was used from the blood samples taken during routine surgery preparation for the patients and from the routine blood samples taken in the postoperative period, and no additional invasive intervention was performed. The investigator elucidated the relationship between quinolinic acid and its variations due to microbiota alterations with VAS in acute pain. Preoperative, postoperative, 8th-hour, and 24th-hour blood samples were routinely collected from patients, with 2 mL of sample material used each time. After the necessary centrifugation processes, the relevant laboratory team analyzed the quinolinic acid levels (ng/mL).
Measured: Preoperative: Before surgery; Postoperative 8th-hour: 8 hours after surgery;Postoperative 24th-hour: 24 hours after surgery
Tryptophan metabolites (Kynurenic Acid)
2 mL of blood was used from the blood samples taken during routine surgery preparation for the patients and from the routine blood samples taken in the postoperative period, and no additional invasive intervention was performed. The investigator elucidated the relationship between kynurenic acid and its variations due to microbiota alterations with VAS in acute pain. Preoperative, postoperative, 8th-hour, and 24th-hour blood samples were routinely collected from patients, with 2 mL of sample material used each time. After the necessary centrifugation processes, the relevant laboratory team analyzed the kynurenic acid levels (ng/mL).
Measured: Preoperative: Before surgery; Postoperative 8th-hour: 8 hours after surgery;Postoperative 24th-hour: 24 hours after surgery
Tryptophan metabolites (Xanthurenic Acid)
2 mL of blood was used from the blood samples taken during routine surgery preparation for the patients and from the routine blood samples taken in the postoperative period, and no additional invasive intervention was performed. The investigator elucidated the relationship between xanthurenic acid and its variations due to microbiota alterations with VAS in acute pain. Preoperative, postoperative, 8th-hour, and 24th-hour blood samples were routinely collected from patients, with 2 mL of sample material used each time. After the necessary centrifugation processes, the relevant laboratory team analyzed the xanthurenic acid levels (ng/mL).
Measured: Preoperative: Before surgery; Postoperative 8th-hour: 8 hours after surgery;Postoperative 24th-hour: 24 hours after surgery
Visual Analog Scale
In VAS assessment, patients are typically asked to choose a value between "0, no pain" and "10, the worst imaginable pain." VAS is an 11-point scale (ranging from 0 to 10) that allows patients to numerically express the intensity of their pain. Blood samples were planned and collected from patients during the preoperative evaluation, at the 8th postoperative hour, and at the 24th postoperative hour, adhering to clinical routines for these procedures. Concurrently with each blood draw, the patient's VAS score, the nature of the pain, and vital signs were recorded.
Measured: Preoperative: Before surgery; Postoperative 8th-hour: 8 hours after surgery;Postoperative 24th-hour: 24 hours after surgery
Secondary outcomes (14)
Systolic Blood Pressure (mmHg)
The study measured the systolic blood pressure (mmHg) of patients at specified time points.The patients' systolic blood pressure data were recorded simultaneously with the blood samples taken during routine surgery preparation and at the 8th and 24th hours postoperatively.
Measured: Preoperative: Before surgery; Postoperative 8th-hour: 8 hours after surgery;Postoperative 24th-hour: 24 hours after surgery
Diastolic Blood Pressure (mmHg)
The study measured the diastolic blood pressure (mmHg) of patients at specified time points.The patients' diastolic blood pressure data were recorded simultaneously with the blood samples taken during routine surgery preparation and at the 8th and 24th hours postoperatively.
Measured: Preoperative: Before surgery; Postoperative 8th-hour: 8 hours after surgery;Postoperative 24th-hour: 24 hours after surgery
Pulse Rate (beats per minute)
The study measured patients' pulse rate (beats per minute) at specified time points.The patients' pulse data were recorded simultaneously with the blood samples taken during routine surgery preparation and at the 8th and 24th hours postoperatively.
Measured: Preoperative: Before surgery; Postoperative 8th-hour: 8 hours after surgery;Postoperative 24th-hour: 24 hours after surgery
Respiratory Rate (breaths per minute)
The study measured the respiratory rate (breaths per minute) of patients at specified time points.
The patients' respiratory rate data were recorded simultaneously with the blood samples taken during routine surgery preparation and at the 8th and 24th hours postoperatively.
Measured: Preoperative: Before surgery; Postoperative 8th-hour: 8 hours after surgery;Postoperative 24th-hour: 24 hours after surgery
Oxygen Saturation (%)
The study measured patients' oxygen saturation (%) at specified time points.The patients' oxygen saturation data were recorded simultaneously with the blood samples taken during routine surgery preparation and at the 8th and 24th hours postoperatively.
Measured: Preoperative: Before surgery; Postoperative 8th-hour: 8 hours after surgery;Postoperative 24th-hour: 24 hours after surgery
Nature of Postoperative Pain Assessed by the McGill Pain Questionnaire (MPQ)
The McGill Pain Questionnaire (MPQ) was used to evaluate and categorize the nature of pain. The study assessed the nature and quality of acute postoperative pain using the McGill Pain Questionnaire (MPQ) at specified time points. Although all of the patients' pain was acute postoperative pain, the pain qualities were recorded simultaneously, taking into account the differences in pain qualities. The MPQ was used to evaluate and categorize the nature of pain. The MPQ includes descriptors of pain which are categorized into sensory, affective, evaluative, and miscellaneous dimensions. Each descriptor is rated on an intensity scale of 0 (none) to 3 (severe), and scores are summed to provide an overall pain score. Higher scores indicate worse pain.
Measured: Preoperative: Before surgery; Postoperative 8th-hour: 8 hours after surgery;Postoperative 24th-hour: 24 hours after surgery
Comorbidity Assessment in Relation to Pain and Tryptophan Metabolites
The study recorded patients' comorbidities, specifically those identified during the preoperative anamnesis process, and evaluated their potential impact on the nature of pain and tryptophan metabolites. Comorbidities identified as exclusion criteria, particularly those believed to affect intestinal microbiota and related to abdominal conditions, were also considered. Patients' comorbidities identified during the preoperative anamnesis process were meticulously documented to assess their influence on pain characteristics and tryptophan metabolites. Additionally, comorbidities identified as exclusion criteria due to their potential to alter intestinal microbiota and their association with abdominal conditions were thoroughly evaluated.
Measured: Preoperative anamnesis process: Prior to surgery, during patient assessment, Follow-up: Through study completion, an average of 1 year
Anesthesia induction drugs
Although standardization of drugs used in anesthesia is difficult, standardization of induction drugs was partially achieved because the investigators chose a single surgery group. The investigators recorded all of this data during anesthesia applications.
Measured: During anesthesia procedure
Anesthesia duration and surgery times
Our study detailedly recorded the duration of anesthesia and surgery. To ensure a certain level of standardization, we included only lumbar disc surgery, which is considered sterile. Additionally, surgeries shorter than a specified duration were excluded as they might not provide significant metabolic changes. These durations were carefully recorded throughout the entire surgery and anesthesia period. The investigators accepted these durations as one of the elimination criteria due to their potential impact on pain and physiological mechanisms.
Measured: During surgery
Age of Investigator
The investigator's age was recorded during the preoperative anamnesis process to understand its influence on the study variables.
Measured: Preoperative: During the preoperative anamnesis process
Weight of Investigator
The weight of the investigator was recorded during the preoperative anesthesia process to understand its influence on the study variables.
Measured: Preoperative: During the preoperative anamnesis process
Height of Investigator
The height of the investigator was recorded during the preoperative anamnesis process to understand its influence on the study variables.
Measured: Preoperative: During the preoperative anamnesis process
Body Mass Index (BMI) of Investigator
The Body Mass Index (BMI) of the investigator was calculated from recorded height (in meters) and weight (in kilograms) during the preoperative anamnesis process to understand its influence on the study variables.BMI values are reported in units of kg/m².
Measured: Preoperative: During the preoperative anamnesis process
Gender of Investigator
The gender of the investigator was recorded during the preoperative anamnesis process to understand its influence on the study variables.
Measured: Preoperative: During the preoperative anamnesis process
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted16 Jul 2024
- Study start12 Jan 2022
- Primary completion24 Nov 2022
- Study completion15 Mar 2023
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (1)Papers the sponsor has linked to this study.
- Other trials for Microbial SubstitutionStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Observational
- Observational model
- Cohort
- Time perspective
- Prospective
- Enrolment
- 37 participants (actual)
- Target duration
- 1 Year
Sponsor and investigators
- Lead sponsor
- Dokuz Eylul University
- Sponsor type
- University, hospital or other
- Responsible party
- Principal investigator, Yunus Çelik, MD, Dokuz Eylul University
- Investigators
- Yunus Celik, M.D., Study chair, Dokuz Eylül University Hospital, Faculty of Medicine
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06502223
- Sponsor's protocol ID
- DEU-Çelik001
- Status last verified
- Jul 2024
- First submitted
- 28 Jun 2024
- Last updated
- 16 Jul 2024
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- Undecided: The investigators do not see any harm in sharing the data of our study to contribute to other studies and meta-analyses. The investigators received our informed consent, but the investigators made such a choice because the investigators doubted that it would be public.
Publications
Celik Y, Aksu H, Gunenc FS, Kalemci O, Kizmazoglu C, Keskinoglu P. Association between circulating tryptophan metabolites and postoperative pain intensity in lumbar disc herniation surgery: An observational study. Medicine (Baltimore). 2025 Aug 1;104(31):e43704. doi: 10.1097/MD.0000000000043704.
PubMed 40760513
Study at a glance
From the registry record, last updated by the sponsor on 16 Jul 2024. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- The Impact of Microbiota and Associated Blood Tryptophan Metabolites on Pain Perception in Patients Undergoing Lumbar Disc Herniation Surgery
- ClinicalTrials.gov ID
- NCT06502223
- Acronym / sponsor ID
- DEU-Çelik001
- Keywords
- Microbiota, Tryptophan, Picolinic Acid, Kynurenic Acid, Xanthurenic Acid, Quinolinic Acid, Acute Pain
- Study type
- Observational
- Recruitment status
- Completed
- Enrolment
- 37 participants (actual)
- Lead sponsor
- Dokuz Eylul UniversityUniversity, hospital or other
- Study start
- 12 Jan 2022 (actual)
- Primary completion
- 24 Nov 2022 (actual)
- Study completion
- 15 Mar 2023 (actual)
- First posted
- 16 Jul 2024 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
It is well-established that the gut microbiota plays a crucial role in various pain mechanisms, including visceral pain, inflammatory pain, headache, neuropathic pain, and opioid tolerance. Changes in the gut microbiome can alter pain perception. In our study, The investigator investigated the effects of microbiota alterations and the associated tryptophan metabolites on acute pain using the Visual Analog Scale (VAS).
Detailed description
The study included patients aged 18 and above undergoing lumbar disc herniation surgery. Blood samples were collected preoperatively, at 8 hours, and at 24 hours postoperatively to analyze tryptophan metabolites (picolinic acid, 3- Hydroxykynurenine, anthranilic acid, kynurenine, quinolinic acid, kynurenic acid, xanthurenic acid). Concurrent VAS pain assessments were conducted, and correlations between tryptophan metabolites and VAS were evaluated.
Study design
- Observational model
- Cohort
- Time perspective
- Prospective
- Target follow-up
- 1 Year
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Age groups
- Adult, Older adult
- Study population
- Our study includes 37 lumbar disc herniation (LDH) surgeries performed in Dokuz Eylül University Faculty of Medicine Central Operating Rooms Brain and Nerve Surgery Hall. For the blood samples in which the investigators evaluated tryptophan metabolites; 2 mL of blood was used from the blood samples taken during routine surgery preparation for the patients and from the routine blood samples taken in the postoperative period, and no additional invasive intervention was performed. Concurrently with each blood draw, the patient's VAS score, the nature of the pain, and vital signs were recorded. Patient records, clinical histories, examination findings, and relevant laboratory results were electronically recorded.
Key inclusion criteria (4 listed)
- Patients undergoing lumbar disc herniation surgery at Dokuz Eylül University Hospital.
- Patients who have read and consented to the informed consent form for the study.
- Age 18 years or older.
- Surgery duration exceeding 2 hours.
Key exclusion criteria (6 listed)
- Patients are unwilling to participate in the study.
- Surgery duration less than 2 hours.
- Patients under the age of 18.
- Patients with a history of abdominal surgery.
- Patients who received antibiotic therapy for intestinal pathology within the last 3 weeks.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| Pain Perception in Patients Undergoing Lumbar Disc Herniation SurgeryAlso: Microbiota and Associated Blood Tryptophan Metabolites onAnalyze tryptophan metabolites (picolinic acid, 3- Hydroxykynurenine, anthranilic acid, kynurenine, quinolinic acid, kynurenic acid, xanthurenic acid). Concurrent VAS pain assessments were conducted, and correlations between tryptophan metabolites and VAS were evaluated. | Procedure or surgery | – |
Primary outcome
Tryptophan metabolites (Picolinic Acid)
Time frame: Preoperative: Before surgery; Postoperative 8th-hour: 8 hours after surgery;Postoperative 24th-hour: 24 hours after surgery
2 mL of blood was used from the blood samples taken during routine surgery preparation for the patients and from the routine blood samples taken in the postoperative period, and no additional invasive intervention was performed. The investigator elucidated the relationship between picolinic acid and its variations due to microbiota alterations with VAS in acute pain. Preoperative, postoperative, 8th-hour, and 24th-hour blood samples were routinely collected from patients, with 2 mL of sample material used each time. After the necessary centrifugation processes, the relevant laboratory team analyzed the picolinic acid levels (ng/mL).
Tryptophan metabolites (3-Hydroxykynurenine)
Time frame: Preoperative: Before surgery; Postoperative 8th-hour: 8 hours after surgery;Postoperative 24th-hour: 24 hours after surgery
2 mL of blood was used from the blood samples taken during routine surgery preparation for the patients and from the routine blood samples taken in the postoperative period, and no additional invasive intervention was performed. The investigator elucidated the relationship between 3-Hydroxykynurenine and its variations due to microbiota alterations with VAS in acute pain. Preoperative, postoperative 8th-hour, and 24th-hour blood samples were routinely collected from patients, with 2 mL of sample material used each time. After the necessary centrifugation processes, the relevant laboratory team analyzed the 3-Hydroxykynurenine levels(ng/mL).
Tryptophan metabolites (Anthranilic Acid)
Time frame: Preoperative: Before surgery; Postoperative 8th-hour: 8 hours after surgery;Postoperative 24th-hour: 24 hours after surgery
2 mL of blood was used from the blood samples taken during routine surgery preparation for the patients and from the routine blood samples taken in the postoperative period, and no additional invasive intervention was performed. The investigator elucidated the relationship between anthranilic acid and its variations due to microbiota alterations with VAS in acute pain. Preoperative, postoperative, 8th-hour, and 24th-hour blood samples were routinely collected from patients, with 2 mL of sample material used each time. The relevant laboratory team measured the anthranilic acid levels (ng/mL) following the required centrifugation procedures.
Tryptophan metabolites (Kynurenine)
Time frame: Preoperative: Before surgery; Postoperative 8th-hour: 8 hours after surgery;Postoperative 24th-hour: 24 hours after surgery
2 mL of blood was used from the blood samples taken during routine surgery preparation for the patients and from the routine blood samples taken in the postoperative period, and no additional invasive intervention was performed. The investigator elucidated the relationship between kynurenine and its variations due to microbiota alterations with VAS in acute pain. Preoperative, postoperative, 8th-hour, and 24th-hour blood samples were routinely collected from patients, with 2 mL of sample material used each time. After the necessary centrifugation processes, the relevant laboratory team analyzed the kynurenine levels (ng/mL).
Tryptophan metabolites (Quinolinic Acid)
Time frame: Preoperative: Before surgery; Postoperative 8th-hour: 8 hours after surgery;Postoperative 24th-hour: 24 hours after surgery
2 mL of blood was used from the blood samples taken during routine surgery preparation for the patients and from the routine blood samples taken in the postoperative period, and no additional invasive intervention was performed. The investigator elucidated the relationship between quinolinic acid and its variations due to microbiota alterations with VAS in acute pain. Preoperative, postoperative, 8th-hour, and 24th-hour blood samples were routinely collected from patients, with 2 mL of sample material used each time. After the necessary centrifugation processes, the relevant laboratory team analyzed the quinolinic acid levels (ng/mL).
Tryptophan metabolites (Kynurenic Acid)
Time frame: Preoperative: Before surgery; Postoperative 8th-hour: 8 hours after surgery;Postoperative 24th-hour: 24 hours after surgery
2 mL of blood was used from the blood samples taken during routine surgery preparation for the patients and from the routine blood samples taken in the postoperative period, and no additional invasive intervention was performed. The investigator elucidated the relationship between kynurenic acid and its variations due to microbiota alterations with VAS in acute pain. Preoperative, postoperative, 8th-hour, and 24th-hour blood samples were routinely collected from patients, with 2 mL of sample material used each time. After the necessary centrifugation processes, the relevant laboratory team analyzed the kynurenic acid levels (ng/mL).
Tryptophan metabolites (Xanthurenic Acid)
Time frame: Preoperative: Before surgery; Postoperative 8th-hour: 8 hours after surgery;Postoperative 24th-hour: 24 hours after surgery
2 mL of blood was used from the blood samples taken during routine surgery preparation for the patients and from the routine blood samples taken in the postoperative period, and no additional invasive intervention was performed. The investigator elucidated the relationship between xanthurenic acid and its variations due to microbiota alterations with VAS in acute pain. Preoperative, postoperative, 8th-hour, and 24th-hour blood samples were routinely collected from patients, with 2 mL of sample material used each time. After the necessary centrifugation processes, the relevant laboratory team analyzed the xanthurenic acid levels (ng/mL).
Visual Analog Scale
Time frame: Preoperative: Before surgery; Postoperative 8th-hour: 8 hours after surgery;Postoperative 24th-hour: 24 hours after surgery
In VAS assessment, patients are typically asked to choose a value between "0, no pain" and "10, the worst imaginable pain." VAS is an 11-point scale (ranging from 0 to 10) that allows patients to numerically express the intensity of their pain. Blood samples were planned and collected from patients during the preoperative evaluation, at the 8th postoperative hour, and at the 24th postoperative hour, adhering to clinical routines for these procedures. Concurrently with each blood draw, the patient's VAS score, the nature of the pain, and vital signs were recorded.
14 secondary outcomes
Systolic Blood Pressure (mmHg)
Time frame: Preoperative: Before surgery; Postoperative 8th-hour: 8 hours after surgery;Postoperative 24th-hour: 24 hours after surgery
Diastolic Blood Pressure (mmHg)
Time frame: Preoperative: Before surgery; Postoperative 8th-hour: 8 hours after surgery;Postoperative 24th-hour: 24 hours after surgery
Pulse Rate (beats per minute)
Time frame: Preoperative: Before surgery; Postoperative 8th-hour: 8 hours after surgery;Postoperative 24th-hour: 24 hours after surgery
Respiratory Rate (breaths per minute)
Time frame: Preoperative: Before surgery; Postoperative 8th-hour: 8 hours after surgery;Postoperative 24th-hour: 24 hours after surgery
Oxygen Saturation (%)
Time frame: Preoperative: Before surgery; Postoperative 8th-hour: 8 hours after surgery;Postoperative 24th-hour: 24 hours after surgery
Nature of Postoperative Pain Assessed by the McGill Pain Questionnaire (MPQ)
Time frame: Preoperative: Before surgery; Postoperative 8th-hour: 8 hours after surgery;Postoperative 24th-hour: 24 hours after surgery
Comorbidity Assessment in Relation to Pain and Tryptophan Metabolites
Time frame: Preoperative anamnesis process: Prior to surgery, during patient assessment, Follow-up: Through study completion, an average of 1 year
Anesthesia induction drugs
Time frame: During anesthesia procedure
Anesthesia duration and surgery times
Time frame: During surgery
Age of Investigator
Time frame: Preoperative: During the preoperative anamnesis process
Weight of Investigator
Time frame: Preoperative: During the preoperative anamnesis process
Height of Investigator
Time frame: Preoperative: During the preoperative anamnesis process
Body Mass Index (BMI) of Investigator
Time frame: Preoperative: During the preoperative anamnesis process
Gender of Investigator
Time frame: Preoperative: During the preoperative anamnesis process
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 16 Jul 2024.
- Derived from this study: PubMed 40760513Celik Y, Aksu H, Gunenc FS, Kalemci O, Kizmazoglu C, Keskinoglu P. Association between circulating tryptophan metabolites and postoperative pain intensity in lumbar disc herniation surgery: An observational study. Medicine (Baltimore). 2025 Aug 1;104(31):e43704. doi: 10.1097/MD.0000000000043704.
- Individual participant dataSharing planned: Undecided. The investigators do not see any harm in sharing the data of our study to contribute to other studies and meta-analyses. The investigators received our informed consent, but the investigators made such a choice because the investigators doubted that it would be public.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Yunus Celik, M.D. study chair
Dokuz Eylül University Hospital, Faculty of Medicine
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Microbial Substitution and Tryptophan Metabolism Alterations, run by Dokuz Eylul University at 1 site in Turkey (Türkiye).
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 4 inclusion and 6 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 16 Jul 2024. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Turkey (Türkiye). Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Tryptophan metabolites (Picolinic Acid) (time frame: Preoperative: Before surgery; Postoperative 8th-hour: 8 hours after surgery;Postoperative 24th-hour: 24 hours after surgery). The study lists 8 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT06502223, which also lists 1 linked publication.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 16 Jul 2024.