European Journal of Cardiovascular Medicine

A pathological anterior displacement of one vertebral body in relation to another is called lumbar spondylolisthesis, and it commonly results in severe back pain, radiculopathy, and a reduced quality of life. The two most prevalent varieties are degenerative and isthmic, which usually impact adults and adolescents, respectively. The Camino Gagnet P et al., Willhuber G et al.^[1,2]. Because of the biomechanical stress and mobility of the L4-L5 segment, single-level spondylolisthesis is very prevalent there. Saremi A. et al. ^[3]

Surgical surgery is required when conservative measures, such as analgesics, physical therapy, and epidural injections, are unable to reduce symptoms. Cho J. and others ^[4]. Because of its effectiveness in spinal decompression, disc height restoration, interbody fusion, and neural compression reduction, TLIF has become a preferred surgical method among those now available. Kim CH et al., Lee HJ et al.,^[5,6.] TLIF minimises iatrogenic instability by providing posterior access for both decompression and fusion utilising an interbody cage and pedicle screws in a single step. Reduced neuronal retraction, high fusion rates, and positive functional results are some of its benefits.Lin GX et al.^[7]

The effectiveness of TLIF in treating lumbar

spondylolisthesis has been supported by numerous studies

that highlight improved pain scores, enhanced functional outcomes, and high rates of fusion success. However, the extent and nature of these improvements can vary significantly depending on a multitude of factors including the patient's age, the level of spondylolisthesis, the presence of comorbidities, and the specifics of the surgical technique employed. Moreover, while the benefits of TLIF are widely recognized, the procedure is not devoid of complications, which can include hardware failure, pseudoarthrosis, infection, and nerve injury. Zheng S et al.^[8]

This study was designed to evaluate the functional recovery of patients undergoing TLIF for symptomatic single-level spondylolisthesis by examining surgical parameters, fusion success, pain relief, complication rates, and postoperative mobility.

AIM AND OBJECTIVES

Aim: To study the functional outcome of spinal fixation and spinal fusion with TLIF in symptomatic single-level lumbar spondylolisthesis.

Objectives:

To evaluate the TLIF outcomes with respect to:

1. Duration of surgery
2. Blood loss
3. Time to mobilization
4. Wound healing
5. Postoperative pain relief
6. Time to fusion
7. Early and late complications

Study Design and Setting

This was a prospective observational study carried out from April 2023 to March 2025 at the Department of Orthopaedics, MGM Medical College and Hospital, Chh. Sambhajinagar, a tertiary care center with expertise in spine surgeries.

Sample Size

The sample comprised 36 patients with symptomatic single-level lumbar spondylolisthesis who fulfilled the inclusion criteria and provided informed consent.

Inclusion Criteria

• Adults aged 18–60 years
• Diagnosed with single-level spondylolisthesis confirmed by X-ray and MRI
• Persistent symptoms despite 6 weeks of conservative treatment
• Presence of clinical signs including positive SLR or femoral stretch test
• Radiological correlation with clinical symptoms

Exclusion Criteria

• Multi-level spondylolisthesis
• Cauda equina syndrome
• Previous lumbar surgery
• Comorbid neurological conditions (e.g. Parkinson’s disease, tumors)
• Lack of clinical-radiological correlation

Surgical Procedure

All patients underwent standard TLIF under general anesthesia. The surgical steps included:

1. Midline posterior approach
2. Pedicle screw placement
3. Decompression via facetectomy and laminectomy
4. Disc removal and endplate preparation
5. Insertion of a PEEK cage with bone graft
6. Rod fixation and closure

Assessment Schedule

• Preoperative: ODI, VAS, MRI, X-rays
• Postoperative: Clinical and radiological evaluations at immediate post-op, 2 weeks, 6 weeks, 12 weeks, and 24 weeks

Data Collection Parameters

• Duration of surgery (minutes)
• Blood loss (ml)
• Time to mobilization (hours)
• Wound healing (days)
• Pain relief (VAS score)
• Functional improvement (ODI score)
• Fusion status at 6 months (X-ray)
• Complications (intra-op and post-op)

Statistical Analysis

Data were analyzed using SPSS version 19. Repeated measures ANOVA was used to compare outcomes at different time points. Significance was set at p<0.05.

Demographics

• Mean age: 45.2 years
• Gender: 20 males, 16 females
• Most common level: L4-L5 (72%)

Table 1: Baseline Demographics and Clinical Characteristics of Patients (n = 36)

The study population's preoperative profile is shown in this table. The average age was 45.2 years, and 55.6% of the population was male. The most often impacted spinal levels were L4–L5 (72%), followed by L5–S1 (28%). Every patient had persistent back pain when they first arrived, and 42% had neurogenic claudication and 78% had radiculopathy. Eighty-three percent of the subjects showed positive nerve stress indicators, such as the femoral stretch test or the straight leg raise, and all reported symptoms that had persisted for longer than six weeks and had not improved with conservative treatment. A homogeneous group of patients with strong clinical and radiological indications for surgery are represented in these results.

Table 2: Surgical Parameters

The intraoperative and early postoperative results of TLIF surgery are shown in this table. With a mean blood loss of 350 millilitres and an average operating time of 180 minutes, the procedure was considered somewhat complicated. Within an average of 36 hours after surgery, patients were mobilised, and wounds healed in 12 days on average. These metrics highlight TLIF's procedural effectiveness as well as its capacity to promote early recovery and shorten hospital stays.

Table 3: Functional Scores (VAS and ODI) Over Time

                                             Both VAS and ODI improvements were statistically significant (p < 0.001).

The longitudinal improvement in pain and impairment after TLIF is shown in this table. At every follow-up point, there were steady and noteworthy declines in the Oswestry Disability Index (ODI) and Visual Analogue Scale (VAS) scores. Significant pain alleviation was shown by the VAS, which dropped from 8.2 before surgery to 1.5 after six months (an improvement of 81.7%). The ODI scores also increased, going from 58.5% to 12.6%, which indicates a 78.4% decrease in impairment. These outcomes demonstrate how well TLIF works to improve quality of life in the early postoperative phase and restore spinal function.

Table 4: Surgical and Postoperative Outcomes

Table 4 provides a detailed analysis of surgical and postoperative outcomes for the study participants. The duration of surgery averaged 81.25 minutes with a standard deviation of 18.2 minutes, ranging from 60 to 105 minutes. Blood loss during surgery was reported at an average of 412.5 ml, with a standard deviation of 89.3 ml, and varied from 300 to 600 ml. The time to mobilize post-surgery was relatively quick, with an average of 2.03 days and a narrow standard deviation of 0.18 days, indicating a consistent and swift recovery process, spanning 2 to 3 days. Hospital stays ranged from 3 to 6 days, with an average of 3.97 days and a standard deviation of 0.88 days. Effective pain management procedures were suggested by the fact that radicular discomfort disappeared on average 3.78 days after surgery, with a standard variation of 1.02 days and a range of 2 to 5 days.

Fusion Rate

• At 6 months: 33 out of 36 patients (91.6%) demonstrated radiological evidence of fusion.

Complications

• Intra-op dural tear: 1 patient (managed conservatively)
• Superficial wound infection: 2 patients (resolved with antibiotics)
• No cases of deep infection, hardware failure, or pseudoarthrosis

TLIF has become a standard surgical option for managing single-level lumbar spondylolisthesis due to its favorable biomechanical and clinical outcomes Chan AK et al. (2023)^[9]. This study reaffirms that TLIF provides excellent functional recovery, evident by significant improvement in VAS and ODI scores, as well as early mobilization and minimal complications.

The observed mean blood loss and surgical time in our study are consistent with reports by Elgafy H et al. and Roh YH et al., who noted average durations of 160–200 minutes and 300–400 ml blood loss ^[10,11].

Fusion rates above 90% are comparable to findings by Wang Y  et al., who reported 92% fusion at one year post-TLIF^[12]. The low incidence of complications in our series

is attributed to meticulous surgical technique and proper patient selection.

The reduction in VAS and ODI scores supports earlier studies by Hu W et al. and Mobbs RJ et al., who emphasized the effectiveness of TLIF in reducing both back and radicular pain ^[13,14]. Moreover, early mobilization within 48 hours and satisfactory wound healing indicate enhanced postoperative recovery.

While ALIF and PLIF are viable alternatives, TLIF offers the advantage of single-incision posterior access with direct decompression and fusion, reducing the need for anterior exposure and its associated risks Moses ZB et al. and de Kunder SL et al.^[15,16].

Limitations of this study include a relatively small sample size and a short follow-up period (6 months). Long-term data beyond 1 year would further strengthen the conclusions.

This study shows that transforaminal lumbar interbody fusion (TLIF) is a safe, dependable, and successful surgical procedure for treating symptomatic single-level lumbar spondylolisthesis. Significant therapeutic advantages result from the procedure's facilitation of direct neural decompression, disc height restoration, and stable spinal fusion via a posterior route. Patients in this trial showed considerable functional recovery as shown by better ODI scores and marked improvements in pain reduction as indicated by significant decreases in VAS scores. Early observance of these changes and their maintenance during the 6-month follow-up period point to a quick and long-lasting surgical recovery.

Additionally, the low incidence of complications and high fusion rate confirm the safety and effectiveness of TLIF when carried out with the right patient selection and surgical skill. Relatively brief hospital stays and early postoperative mobilisation improved overall patient satisfaction while lessening the strain on healthcare systems. The results of this study suggest TLIF as a preferable surgical technique in patients with single-level lumbar spondylolisthesis that are recalcitrant to conservative therapy, despite limitations related to sample size and short follow-up length. To confirm these results and improve surgical decision-making, multicenter trials with comparison cohorts and extended follow-up are crucial.

LIMITATIONS OF THE STUDY

Despite yielding valuable insights into the functional recovery of patients undergoing TLIF for symptomatic single-level lumbar spondylolisthesis, this study is subject to certain limitations that may affect the interpretation and generalizability of its findings:

1. Small Sample Size (n = 36)

The study's statistical power is limited by the very small sample size. Detecting modest but clinically significant changes or relationships is restricted with just 36 individuals, particularly in subgroup analysis (e.g., age, gender, severity of spondylolisthesis). Additionally, small sample sizes may not accurately reflect the larger population of patients having TLIF and are more vulnerable to the effects of random fluctuation. Larger multi-center investigations are thus necessary to confirm and build on these results.

2. Limited Duration of Follow-Up (6 Months)

Although early pain alleviation, functional improvement, and initial fusion trends may be evaluated throughout the 6-month surgical follow-up period, this time frame does not account for the long-term durability of these results. Pseudoarthrosis, neighbouring segment degeneration, hardware loosening, and recurring symptoms are examples of delayed problems that might occur after a year after spinal fusion, especially in spondylolisthesis. It is difficult to assess how long surgical effectiveness lasts or spot late-emerging problems without long-term follow-up.

3. Single-Center Study Without a Control Group

The fact that the investigation was only carried out at one tertiary care facility raises the possibility of institutional or surgeon-related bias. External validity may be limited since MGM Medical College and Hospital's surgical competence, postoperative care procedures, and patient demographics might not be representative of those of other facilities. Furthermore, a direct assessment of the relative effectiveness or superiority of TLIF is not possible due to the lack of a comparison control group, such as patients receiving alternative surgical procedures (PLIF, ALIF, or conservative treatment). The findings would have been stronger with a randomised controlled trial design.

4. Fusion Assessment Based Solely on X-ray Imaging

The effectiveness of the fusion was assessed using plain radiographs, which are less sensitive and specific than more sophisticated imaging modalities like computed tomography (CT), despite being generally accessible and practical. Because of their limits in identifying trabecular continuity and interference from metallic implants, X-rays may either overstate or underestimate fusion. Better visualisation of the interbody graft and surrounding bone is possible with CT imaging, enabling a more conclusive assessment of the fusion status. As a result, depending exclusively on X-rays might jeopardise the precision of the fusion evaluation in this research.

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