Lumbar disc herniation is a commonly prevalent spinal disorder that can progress to radiculopathy. This can result in lower back pain, and neurological deficits and can significantly impact the quality of life. Surgical intervention in the form of lumbar discectomy is the treatment of choice when conservative management fails to alleviate symptoms. Primary lumbar discectomy is a procedure in which a part of herniated disc material is removed to decompress the affected nerve root and is one of the commonly performed spinal procedure across the world. It has a relatively high success rate and generally has favorable outcomes in terms of pain relief and functional improvement [1]. Although primary discectomy has a higher positive outcome in some cases, the patients experience recurrent disc herniation at the same level. The incidence of recurrent herniation is approximately 5 -15% of the cases. Most of this recurrent herniation occurs within the first two years of the primary surgery [2]. This requires revision surgery to be performed at the same level. Technically revision lumbar discectomy is more challenging due to scar tissue formation, altered anatomy, and risk of complications such as dural tears and nerve root injury [3]. As a result, the outcomes of revision discectomy can often vary and may not be as good as those observed following primary discectomy. A comparison of the outcomes of primary revision versus revision lumbar discectomy is important for clinical decision-making and patient counseling. The evidence shows that primary discectomy produces superior outcomes but revision procedures produce some meaningful results alongside elevated complication rates and higher symptom persistence risks [4]. Multiple factors affect surgical outcomes for patients because of their age alongside their BMI measurements and symptom duration and also their smoking history as well as psychological state and additional health problems including diabetes and osteoporosis [5].

Few studies have been done to delineate the difference in the clinical and function outcomes between primary and revision discectomy. A retrospective cohort study by Suk et al. [6] has shown that both groups experience significant postoperative pain relief. The overall patient satisfaction scores were generally found to be higher in cases of primary surgery and they experience fewer complications as compared to those undergoing revision. Carragee et al. [7] in a similar study have shown that there are higher rates of unfavourable outcomes in revision cases showing the importance of patient selection and surgical expertise. Recently there has been a trend to increase in the number of lumbar spine surgeries and increasing incidence of revision procedures, understanding the intricacies related to outcomes following the two approaches is essential. Based on this background we in the current study aimed to determine and compare the clinical efficacy, complication rates, and overall patients overall patient outcomes between primary and revised lumbar discectomy. The findings of our study could contribute to optimizing surgical strategies and tailoring patient-specific treatment plans to improve postoperative results and quality of life.

This prospective comparative cohort study was done in the Department of Neurosurgery, Gandhi Medical College and Hospital, Secunderabad. Institutional Ethical approval was obtained for the study. Written consent was obtained from all the participants of the study after explaining the nature of the study in vernacular language.

Inclusion criteria

1. Adults aged 18 years and above
2. Undergoing primary single-level lumbar discectomy
3. Revision discectomy for symptomatic lumber disc herniation (LDH)
4. Confirmed diagnosis via MRI
5. Minimum follow-up for 12 months

 Exclusion criteria

1. Multilevel surgery, concomitant spinal fusion
2. Other spinal pathologies (e.g., stenosis, spondylolisthesis).
3. Trauma, infection, or malignancy-related surgeries.
4. Incomplete medical records.
5. Not available for follow-up

Data Collection: Data were collected prospectively using standardized clinical forms and electronic medical records. Patient demographics included age, sex, body mass index (BMI), and smoking status. Clinical variables comprised preoperative assessments using the Visual Analog Scale (VAS) for leg and back pain and the Oswestry Disability Index (ODI), along with the duration of symptoms before surgery. Surgical parameters recorded included operative time, estimated blood loss, and intraoperative complications such as dural tears and nerve root injuries. Primary outcomes were defined as a ≥50% reduction in VAS scores and a ≥20-point improvement in ODI at 6 and 12 months postoperatively. Secondary outcomes included reoperation rates, postoperative complications like infection or hematoma, and patient satisfaction measured using a Likert scale.

 Surgical Technique (Primary Discectomy): The standard microdiscectomy is performed via an interlaminar approach under general anesthesia. A small midline incision (~2–3 cm) is made, and muscles are dissected to expose the lamina. Using a microscope or loupe magnification, a partial laminotomy and ligamentum flavum removal are done to access the spinal canal. The herniated disc compressing the nerve root is identified, and the extruded fragments are excised while preserving the annulus. Nerve root decompression is confirmed by free mobility. The wound is closed in layers. This minimally invasive technique minimizes tissue trauma and reduces blood loss (<50 mL). Patients are mobilized the same day. 

Revision Discectomy: Revision discectomy involves re-exploration through the previous surgical scar, with meticulous dissection through fibrotic tissue to access the spinal canal. Under intraoperative neuromonitoring (IONM) guidance, neural decompression is performed by removing recurrent disc fragments and/or epidural scar tissue compressing nerve roots. Adhesiolysis is carefully conducted to minimize dural or neural injury. The extent of decompression is tailored to pathology, occasionally requiring extended laminectomy or facetectomy. IONM ensures real-time assessment of nerve integrity. The procedure typically lasts 90–120 minutes with higher blood loss (100–300 mL) than primary cases. Postoperatively, patients require close monitoring for CSF leaks or neurological deficits. 

 Statistical analysis: All the available data was refined, segregated, and uploaded to an MS Excel spreadsheet and analyzed by SPSS version 22 in Windows format. The continuous variables were represented as mean, standard deviation, and percentages. The categorical variables were calculated using the Chi-square test for differences between the two groups. The values of p (<0.05) were considered as significant.

Table 1 presents the baseline demographic and clinical characteristics of two groups of patients participating in a comparative study on the outcomes of primary and revision lumbar discectomy surgery. Group A (n=25) represents patients undergoing primary lumbar discectomy for the first time, while Group B (n=25) consists of patients undergoing revision lumbar discectomy (a second or subsequent surgery for recurrent disc herniation at the same level).

The mean age was 45.2 ± 8.5 years in the primary surgery group (Group A) and 48.6 ± 9.1 years in the revision group (Group B). Males comprised 60% of Group A and 52% of Group B. Mean BMI was 26.1 ± 3.2 kg/m² in Group A and 27.4 ± 3.8 kg/m² in Group B. Smokers made up 28% of Group A and 36% of Group B. Symptom duration before surgery averaged 6.2 ± 2.1 months in Group A and 8.5 ± 3.3 months in Group B. Baseline demographics (age, sex, BMI, smoking) were comparable between groups with no statistically significant differences. However, the significantly longer symptom duration in the revision group may reflect more chronic or severe initial pathology and could influence surgical outcomes. This factor should be considered in the interpretation of study results.

*Significant

Table 2 shows the comparison of intraoperative outcomes between the primary surgery and revision lumbar discectomy patients. The mean operative time in the revision surgery was significantly longer (112 ± 28 versus 68 ± 15 minutes) in the primary discectomy patients. This shows that there is a greater complexity in revision surgeries due to distorted anatomy and the presence of scar tissue due to previous surgery. Similarly, the mean blood loss was also comparatively higher in the revision group (185 ± 42 mL vs. 45 ± 18 mL) which could be due to increased vascularity of scar tissue and challenging dissection through adhesions. We also found that 20% of revision cases had dural tears as compared to 4% in the primary surgery cases. Neuromonitoring alerts were absent in group A and were found to be present in 16% of group B cases indicating a higher risk of neural compromise during revision surgery. These results highlight that revision discectomy is a challenging task associated with higher intraoperative risk and requires caution and expertise due to altered anatomy and the presence of scar tissue. 

*Significant

Table 3 presents a comparison of postoperative clinical outcomes between patients VAS Leg Pain (Δ): In the primary surgery group, the VAS score for leg pain improved from a mean of 6.5 preoperatively to 1.8 postoperatively, representing a change of 4.7. In the revision surgery group, the VAS score improved from 6.8 to 2.9, a change of 3.9. ODI Score (Δ): The mean ODI score in the primary surgery group decreased from 62 preoperatively to 18 postoperatively, indicating an improvement of 44 points. In the cases of revision surgery ODI scores decreased from 65 to 32 there was an improvement of 33 points. The mean duration of hospital stay for patients of the primary surgery group was significantly less as compared to the revision surgery group (1.2 ± 0.5 versus 2.8 ± 1.1 days)

Return to Work (weeks): Patients in the primary surgery group returned to work on average after 4.1 weeks (± 1.2 weeks). In contrast, patients in the revision surgery group took significantly longer, with an average of 8.5 weeks (± 2.3 weeks) before returning to work. The analysis of this table shows that patients undergoing primary lumbar discectomy have better outcomes postoperatively as compared to those undergoing revision surgery. The primary group shows significantly improved leg pain and functional disability and a faster return to work. This shows that revision surgery tends to have lesser improvements however, the revision surgeries can provide relief although might not be as favorable as those achieved with primary lumbar discectomy.

*Significant

Table 4 compares the incidence of complications and the need for reoperations within one year following primary lumbar discectomy (Group A) and revision lumbar discectomy (Group B). The rate of surgical site infection was 4% (1 patient) in the primary surgery group and 12% (3 patients) in the revision surgery group. Recurrent herniation occurred in 8% of patients (2 patients) in the primary surgery group, compared to 24% of patients (6 patients) in the revision surgery group. Within one year of the surgery, 4% of patients (1 patient) in the primary surgery group required a reoperation, while 20% of patients (5 patients) in the revision surgery group needed another surgery. Patient satisfaction, defined as reporting excellent or good satisfaction, was 92% in the primary surgery group and 68% in the revision surgery group.

The results of Table 4 demonstrate that revision lumbar discectomy is associated with a higher risk of complications and subsequent surgical interventions compared to primary lumbar discectomy. The results show that patients having revision surgery showed higher recurrent herniation rates and there was a need for reoperation in the first year. There were lower satisfaction scores in the revision group. The rate of surgical site infection was higher in the revision group although not statistically significant. The lower patient satisfaction scores in revision could be because of the increased burden of complications and reoperations. This should be kept in mind while making decisions for revision surgery and patients should be made aware of these factors.

*Significant

Table 5 depicts the Oswestry Disability Index (ODI) outcomes between patients undergoing primary (Group A) and revision (Group B) lumbar discectomy.  The ODI is scored in 10 sections, each covering a different aspect of daily living. Each sub-section is scored from 0 to 5.  A higher score indicates greater disability. The total score is converted into a percentage (out of 50 points, multiplied by 2), giving a disability rating from 0% (no disability) to 100% (maximum disability). A critical analysis of the table shows the total ODI scores, along with p-values for intergroup comparisons. The mean preoperative in the primary group was (62.4 ± 8.2 versus 65.1 ± 9.6) in the revision surgery group. The postoperative ODI showed significant improvement in the primary group (18.3 ± 6.5) compared to 32.7 ± 10.2 in the revision group. Δ ODI improvement was (44.1 ± 7.8) in the primary surgery group and (32.4 ± 9.3) in the revision surgery group. The results consistently show that patients undergoing primary lumbar discectomy experience significantly better outcomes in terms of reduced disability and improvement across most specific domains of the ODI compared to those undergoing revision surgery.  The total postoperative ODI score was substantially lower (indicating less disability) in the primary group. The improvement in ODI was also significantly larger in the primary group. When examining individual domains, the primary surgery group showed statistically significant greater improvement in pain intensity, lifting, walking, and sitting. The improvement in personal care was also numerically greater in the primary group and approached statistical significance. The overall reduction in disability and improvement in specific functional aspects are generally less pronounced than after primary lumbar discectomy.

The present study was done to evaluate the clinical outcomes, intraoperative parameters, and postoperative recovery of a cohort undergoing primary lumbar discectomy versus revision lumbar discectomy. The overall results of this study show that both procedures provide symptomatic relief from pain. However, as expected revision surgeries are associated with longer operative time, increased blood loss higher intraoperative risk, and relatively lower patient satisfaction scores. The comparison of the baseline demographic of our cohort revealed that (age, sex, BMI, and smoking status) were comparable between both groups and the p-values were not significant. This allows for a meaningful comparison between the groups. However, as predicted the preoperative symptoms were of longer duration which is because of the chronic pathology and may be responsible for less favorable outcomes later on. Similar observations have been reported by Atlas SJ et al. [8] where they found that prolonged duration of symptoms before intervention is associated with poorer functional recovery post-discectomy.

Our intraoperative experience showed that the operation was more technically challenging. We had longer operative times which was also associated with greater blood loss. The incidence of dural tears and neuromonitoring alerts were higher in the revision surgery cases. These findings were in concordance with other similar studies [9-11] in the past where there was increased complexity due to distorted anatomy and scar tissue formation which increases the risk of iatrogenic injury [12, 13]. The occurrence of dural tears in revision cases exists in literature from 10 to 20 percent which matches the results of our research. The primary discectomy group achieved superior outcomes concerning VAS for leg pain and ODI scores after surgery. Valid information showed better pain and disability reductions occurred in patients who received primary discectomy as opposed to revision surgery. Sports indicates through its analysis of large patient cohorts that discectomy patients achieve higher functional outcomes after primary discectomy procedures than those undergoing revision surgery [14]. Patients requiring revision surgery spent more time in the hospital until recovery and working again thus demonstrating the prolonged nature of postoperative healing. Suk KS et al. [6] documented parallel findings through their study which showed that hospital costs and recovery periods increase after revision lumbar surgery.

The complications and reoperation rate in this study were found to be higher in the revision group. We had recurrent disc herniation in 24% of the revision cases as compared to 8% of the primary cases within one year of surgery. These findings were concurrent with that of El Shazly et al. who have also reported increased reoperation and lower satisfaction scores among the revision surgery patients. Results of this study demonstrated that lower patient revision was higher in revision the overall satisfaction scores were (68% vs. 92%) similar findings have been reported by other studies done in the past in this area. The delta changes in ODI showed greater improvement in the primary group regarding pain intensity, lifting, walking, and sitting. These functional domains are important in determining quality of life and relatively limited improvements in the revision group. This underlines the importance of early and effective intervention proper selection of cases and patient counseling before revision surgeries and knowing what to expect from these kinds of surgical procedures.

In conclusion, within the limitations of the current study, we found that revision lumbar discectomy can provide substantial symptomatic relief, it carries increased operative risk and yields less favorable outcomes compared to primary discectomy. These findings emphasize the need for careful surgical planning and patient counseling. Shared decision-making should incorporate realistic expectations, especially in revision cases, and highlight the potential risks and benefits based on current evidence.

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