Gender‐Based Analysis of Perioperative and Early Postoperative Complications in Tubular Microdiscectomy for Lumbar Disc Prolapse: A Retrospective Comparative Study

ABSTRACT

Background and Aims

Various anthropometric differences and co‐morbidities have been associated with disparities in postoperative outcomes following spinal surgery. Gender has been identified in previous studies as a potential factor influencing the prevalence of conditions like lumbar disc radiculopathy, degenerative disc disease, and cauda equina syndrome. Our study aimed to evaluate the effect of gender as a risk factor on the rate of perioperative and early postoperative complications after tubular microdiscectomy for lumbar disc prolapse.

Methods

This retrospective multicenter study, conducted in two specialized spine centers in Baghdad, Iraq, involved 302 patients with lumbar disc herniation (174 males and 128 females) from January 2016 to January 2022. Data collection included comprehensive assessments of clinical and surgical outcomes, utilizing the Core Outcome Measures Index (COMI) score at 2, 6, and 12 weeks.

Results

A total of 134 males (77%) and 104 females (81%) were below 40 years old, while 40 males (23% of males) and 24 females (18.8% of females) were 40 or older. There was a significant difference in mean operative times (p < 0.001). The most common specific complication was spondylodiscitis with six males (3.4% of males) and three females (2.3% of females), while the most common general complication was post‐op back spasm with six males (3.4% of males) and four females (3.1% of females). It's noteworthy to emphasize that our analysis showed a non‐significant association of gender with the presence of either specific or general complications (p > 0.05).

Conclusion

Gender has a minimal impact on most perioperative and early postoperative complications. Longer operative times in females raise questions about gender‐specific differences across spine surgeries and specialties, necessitating further research. We also note a shift in the age profile for disc prolapse patients, emphasizing the need for additional research into contributing factors among younger populations.

1. Introduction

Lumbar disc herniation is a common cause of lumbosacral radiculopathy and typically responds to initial conservative care; surgery is reserved for patients with persistent symptoms or progressive neurologic compromise, and urgently for those with cauda equina features [1].

Over the past two decades, minimally invasive tubular microdiscectomy has been adopted as an alternative to conventional microdiscectomy. By dilating rather than stripping paraspinal musculature and working through a small interlaminar corridor, the technique aims to reduce tissue trauma, postoperative pain, and convalescence while maintaining decompressive efficacy [2].

Comparative evidence suggests that tubular and conventional microdiscectomy achieve similar clinical outcomes and complication profiles, with long‐term randomized and pooled data showing no consistent disadvantage for either approach; some analyses note modest improvements in disability with tubular methods [3].

Across spine surgery, patient sex has been explored as a potential determinant of perioperative risk and recovery. Systematic reviews indicate that men may have higher mortality, whereas complication rates appear broadly comparable between sexes; however, procedure‐specific patterns remain incompletely defined [4, 5].

Against this background, we investigated whether sex is associated with perioperative and early postoperative complications after tubular microdiscectomy for lumbar disc prolapse in two specialized centers, using standardized outcome assessments (Core Outcome Measures Index [COMI]) at set intervals [6, 7].

Study aim: to test whether gender independently influences operative parameters and short‐term complication rates in a real‐world cohort (study period, sites, sample, and COMI schedule per your methods).

1.1. Patient and Methods

This is a multicenter retrospective study with prospective data collection from two specialized spine centers located in Baghdad, Iraq. These centers are recognized for their expertise in minimally invasive spine surgery and tubular procedures.

From January 2016 to January 2022, a total of 302 patients diagnosed with lumbar disc herniation, comprising 174 males and 128 females, underwent microscopic tubular discectomy using the Medix Tubular System and Microscope.

Data collection for this study encompassed a comprehensive assessment of clinical and surgical outcomes. The COMI score was employed for evaluating patient outcomes. Data was gathered during preoperative assessments and follow‐up visits conducted at 2, 6, and 12 weeks postoperatively, enabling a detailed examination of patient progress and surgical efficacy.

The study was conducted between January 2016 and January 2022. Ethical approval was obtained from the Royal Private hospital Ethics Committee (Approval No: 001/2022). Written informed consent was obtained from all participants.

1.2. Inclusion Criteria

The inclusion criteria include patients with single or two levels lumbar disc prolapse or those with spinal stenosis due to disc prolapse, provided they have an indication for surgery, which includes individuals who have not responded to conservative treatment for at least 12 weeks or are displaying neurological deficits from disc prolapse. Patients with cauda equina syndrome or bowel/bladder involvement were excluded, as these cases require urgent surgical intervention and could bias complication rates.

1.3. Exclusion Criteria

Patients with lumbar multiple spinal stenosis, tandem pathologies, spondylodiscitis, or spine instability are not eligible.

1.4. Variables

We collected demographic and clinical data from the two groups of patients, including their age and the presence of comorbidities including obesity, hypertension, and diabetes mellitus. We also collected data on operative time, blood loss, and hospital stay, which is defined as the duration from the patient's admission to the ward before surgery to discharge after surgery. This comprehensive measurement provides insights into the surgical aspects of the procedure between the two genders.

We categorized the complications, derived from patient data, into two distinct groups: specific complications, which include spondylodiscitis, superficial wound infection, recurrent disc, dural tear, facet violence, post‐op neuritis, vascular injuries, and post‐op hematoma requiring revision surgery, and general complications, which include deep venous thrombosis, urinary retention, and post‐op back spasm lasting for more than 2 weeks.

1.5. Preoperative Consent

Preoperative written consent was taken from patients. Ethical approval was obtained from the ethical committee in the University of Baghdad, College of Medicine.

1.6. Surgical Technique

Under general anesthesia and endotracheal tube, preoperative antibiotic at the time of anesthesia induction, prone position with Jackson frame to free up the abdomen with padding of knee, elbow, and ankles.

Under fluoroscopy, the level of the spine was identified, and an incision of 1.5–2 cm was made at the site of the pathology; from there, the surgeon chose the interlaminar approach as the main surgical approach. After identifying the nerve root, a discectomy was performed, then a foraminotomy was performed, the wound was closed in layers, and no drain was left. This procedure was performed using an 18‐mm tubular system after serial dilators and fluoroscopy to confirm the correct level and orientation; the tube is connected to the surgical table by the arm, and a neurosurgical microscope is used to perform the surgery.

1.7. Postoperative Care

Postoperative analgesia is advised, and the patient began walking a few hours after anesthesia recovery. The majority of patients were discharged on the same day, unless they experienced intraoperative complications or were unable to initiate ambulation promptly due to postoperative pain.

Stitches were removed 2 weeks later, and clinical and surgical outcomes were assessed using the COMI score in preoperative, postoperative, 2‐, 6‐, and 12‐week visits.

Postoperative MRI is taken for patients with postoperative complications, including CSF leaks, postoperative spondylodiscitis, or radiculopathy.

1.8. Sample Size

An open epi sample size calculator was used to estimate the sample size, taking a confidence interval of 95%, a margin of error of 4.5%, and a reported prevalence of complications in females of 20.2%. The estimated sample size came out to be 302.

1.9. Data Analysis Plan

SPSS version 24 is used for the purpose of statistical analysis. Descriptive analysis was computed in mean ± SD, frequencies, and percentages. Inferential statistics were computed using an independent t‐test and chi‐square/Fisher‐exact test. p‐value < 0.05 is considered significant.

2. Results

The study included a total of 302 patients, with the majority being males of 174 individuals, representing 57.61% of the cohort, while females accounted for 128 patients, representing 42.38% (Table 1).

Table 1.

Comparison of patient demographics and clinical features by gender.

Age (years)	Gender		p‐value
	Male (n = 174)	Female (n = 128) %
< 40	134 (77.0%)	104 (81.2%)	0.373
≥ 40	40 (23.0%)	24 (18.8%)
Comorbidity
No	138 (79.3%)	98 (76.6%)	0.568
Yes	36 (20.7%)	30 (23.4%)
With comorbidity
Obesity	12 (6.9%)	14 (10.9%)	0.270
Hypertension	15 (8.6%)	10 (7.8%)	0.487
Diabetes mellitus	7 (4%)	5 (3.9%)	0.771

Analysis of the patient demographics revealed that a significant proportion of the study population, 134 males (77.0% of males) and 104 females (81.3% of females), were below the age of 40, whereas those aged 40 or older comprised 40 males (23.0% of males) and 24 females (18.8% of females) (Table 1).

Furthermore, a noteworthy finding was that most patients had no comorbidities, with 138 males (79.3% of males) and 98 females (76.6% of females) falling into this category (Table 1).

In addition, it's worth noting that among the patients with comorbidities, the majority had obesity, with 26 cases, further characterizing the health profile of the study population (Table 1).

Furthermore, it's important to highlight that we observed a nonsignificant association between gender and the presence of comorbidities (p‐value 0.568) (Table 1).

According to the findings of our study, there is a statistically significant difference between the mean operative times of males and females (p < 0.001). The mean operative time for females was found to be 72.49 ± 14.03 min, while the mean operative time for males was found to be 63.21 ± 11.20 min. On the other hand, we found that there was no statistically significant difference between the two groups in terms of blood loss (p > 0.99) and hospital stay (p > 0.99) (Table 2).

Table 2.

Gender‐related comparison of operative time, blood loss, hospital stay.

	Males		Females
	Mean ± SD	(min–max)	Mean ± SD	(min–max)	p‐value
Operative time (min)	63.21 ± 11.2	30–110	72.49 ± 14.03	40–100	< 0.001
Blood Loss (ml)	58.89 ± 13.45	3–200	61.21 ± 11.71	35–300	0.119
Hospital Stay (in Hours)	14 ± 10.28	5–36	16 ± 11.58	8–28	0.114

Regarding complications, the data revealed that the most common specific complication was spondylodiscitis with six males (3.4% of males) and three females (2.3% of females), while the most common general complication was post‐op back spasm with six males (3.4% of males) and four females (3.1% of females). It's noteworthy to emphasize that our analysis showed a nonsignificant association of gender with the presence of either specific or general complications (p > 0.01) (Table 3).

Table 3.

Gender‐related comparison of complication rates.

Specific complications	Male (n = 174)	Female (n = 128)	Overall (N = 302)	p‐value
Spondylodiscitis	6 (3.4%)	3 (2.3%)	9 (2.9%)	0.577
Superficial wound infection	2 (1.1%)	1 (0.7%)	3 (1%)	0.750
Recurrent disc prolapse	3 (1.7%)	2 (1.5%)	5 (1.6%)	0.913
Dural tear	4 (2.3%)	1 (0.7%)	5 (1.6%)	0.307
Facet violence	2 (1.1%)	1 (0.7%)	3 (1%)	0.750
Post op neuritis	3 (1.7%)	2 (1.5%)	5 (1.6%)	0.913
Vascular injuries	1 (0.5%)	0	1 (0.3%)	0.390
Postoperative hematoma	0 (0%)	1 (0.7%)	1 (0.3%)	0.098
General complications
DVT	0 (0%)	1 (0.7%)	1 (0.3%)	0.243
Urinary retention	0 (0%)	1 (0.7%)	1 (0.3%)	0.243
Postoperative back spasm	6 (3.4%)	4 (3.1%)	10 (3.3%)	0.877

Baseline COMI pain scores and symptom duration were comparable between males and females (p > 0.05), suggesting no preoperative bias in severity (Table 4).

Table 4.

Baseline comparison of preoperative neurological deficits, pain scores, and symptom duration between male and female patients undergoing tubular microdiscectomy for lumbar disc prolapse.

Variable	Male (n = 174)	Female (n = 128)	Total (n = 302)	p‐value
Neurological deficits—Any, n (%)	58 (33.3%)	46 (35.9%)	104 (34.4%)	0.65
Motor deficit present, n (%)	28 (16.1%)	20 (15.6%)	48 (15.9%)	0.91
Sensory deficit present, n (%)	22 (12.6%)	17 (13.3%)	39 (12.9%)	0.85
Reflex impairment, n (%)	8 (4.6%)	9 (7.0%)	17 (5.6%)	0.38
Pain scores (preoperative)
COMI pain score, mean ± SD	7.8 ± 1.1	8.0 ± 1.0	7.9 ± 1.1	0.22
Back pain VAS (0–10), mean ± SD	6.7 ± 1.2	6.9 ± 1.3	6.8 ± 1.3	0.31
Leg pain VAS (0–10), mean ± SD	7.2 ± 1.0	7.4 ± 1.1	7.3 ± 1.1	0.28
Symptom duration
Duration (weeks), mean ± SD	11.6 ± 3.8	12.1 ± 3.5	11.8 ± 3.7	0.27
< 6 weeks, n (%)	36 (20.7%)	26 (20.3%)	62 (20.5%)	0.92
6‐12 weeks, n (%)	88 (50.6%)	62 (48.4%)	150 (49.7%)	0.72
> 12 weeks, n (%)	50 (28.7%)	40 (31.3%)	90 (29.8%)	0.61

3. Discussion

Significant gender‐based differences in health are the result of a complicated combination of factors, including genetics, physiology, and the environment. Several new reports in the surgical literature suggest there may be significant differences in treatment and outcome based on the patient's gender. The recognition of gender‐related differences enhances our understanding and presents an opportunity for enhancing the standard of healthcare. The different risks posed by each gender can be accommodated by modifying surgical procedures; as a result, the outcomes of surgical procedures can eventually be improved [8, 9, 10].

Our analysis revealed that, while there were various other factors examined, the difference in operative times was the only one that reached statistical significance. Another study by Raheem et al. on transforaminal lumbar interbody fusion (TLIF) surgery suggests a consistent finding of longer operative times for female patients in spine surgery. The consistent finding of longer operative times for female patients in different spine surgeries, as indicated in both our study and the study by Raheem et al., raises questions about potential gender‐related factors contributing to this [11]. It may be important to investigate whether these findings hold true across various types of spine surgeries and whether they extend to other surgical specialties. Longer operative times have various clinical implications, including increased exposure to anesthesia, a higher risk of surgical complications, and potentially longer hospital stays. Understanding the reasons behind this gender difference can help healthcare providers modify their approach to improve outcomes and patient safety [12].

Our study found that there were no statistically significant differences in blood loss or hospital stay duration between males and females. These results suggest that, in the context of our study, gender did not appear to be a significant determinant of these specific patient outcomes.

In the same study by Raheem et al., they reported contrasting findings, indicating that females had more blood loss and longer hospital stays compared to males. These differences in findings may be due to various factors, such as differences in study populations, methodologies, or the specific surgical procedure being investigated [11].

Our analysis revealed a non‐significant association between genders and the presence of either specific or general complications. This indicates that the risk of complications during the perioperative and early postoperative periods appears to be relatively consistent between males and females in tubular microdiscectomy for lumbar disc prolapse. However, it's crucial to continue monitoring and analyzing this aspect in future research to ensure a comprehensive understanding of potential gender‐related healthcare differences. It's noteworthy that previous studies have shown that the average age for individuals with intradural disc herniations tends to fall between 50 and 60 years old [12, 13]. In contrast, our study demonstrated that the majority of patients affected were younger than 40 years old.

This age difference in our study population raises questions about the potential factors contributing to the occurrence of intradural lumbar disc herniations in younger individuals. It suggests that there may be unique risk factors, genetic predispositions, or lifestyle factors that need to be explored in more detail. Understanding why a younger age group is affected could have significant implications for both diagnosis and treatment strategies. The prevalence of comorbidities like obesity, hypertension, and diabetes mellitus tends to rise with age. Consequently, the relatively low occurrence of these comorbidities in our patients is consistent with the findings reported in previous articles and studies [14].

Compared to prior studies that have primarily focused on open or conventional microdiscectomy techniques, our study offers new insights by specifically examining gender‐related differences in outcomes after tubular microdiscectomy—a minimally invasive approach. While previous research, such as that by Raheem et al., has suggested gender disparities in parameters like blood loss and hospital stay, our findings do not replicate those trends in the context of tubular techniques. This underscores the potential influence of surgical modality on perioperative outcomes and highlights the need to reevaluate gender‐based risk profiles in minimally invasive spine surgery. By identifying that only operative time differs significantly by gender, our study contributes to refining perioperative risk stratification models and emphasizes the importance of tailoring surgical approaches to patient‐specific factors.

Subgroup analysis revealed no significant differences in complication rates between younger and older females, or diabetic versus non‐diabetic males, suggesting comorbidities did not confound outcomes.

Female patients required ~9 min longer operative time. Prior morphometric and postural studies suggest females have relatively smaller posterior‐element corridors and distinct facet/lordosis profiles, potentially narrowing the practical interlaminar working space and prolonging meticulous decompression. Similar sex‐linked operative‐time differences have been observed in other lumbar procedures (e.g., TLIF), supporting an anatomic/technical—not institutional—explanation. These hypotheses warrant confirmation in imaging‐correlated prospective studies [15, 16, 17, 18, 19].

4. Limitations

The limited sample size in our study is a critical limitation that affects the study's representativeness, generalizability, and potential bias. Our study's restriction to tubular microdiscectomy for lumbar disc prolapse means that our findings are applicable exclusively to this specific procedure. While this focus provides valuable insights, it is essential to acknowledge that these findings should not be generalized to other surgical specialties.

5. Conclusion

In summary, our study reveals that gender does not significantly influence most patients in terms of perioperative and early postoperative complications. The longer operative times observed for females in our study raise questions about the applicability of this gender‐specific difference to other spine surgeries and surgical specialties, emphasizing the importance of further research into gender‐specific surgical outcomes. Additionally, our findings suggest a shift in the typical age profile for disc prolapse patients, underscoring the necessity for further research into factors that may be contributing to this condition in younger populations.

6. Recommendations

We encourage collaboration among researchers, surgeons, and healthcare institutions to conduct larger and more comprehensive studies on gender‐based outcomes in spine surgeries. This will help in consolidating data and fostering a deeper understanding of the phenomenon. We encourage the medical research community to explore these differences in other surgical and medical specialties. This broader research approach will provide a more comprehensive understanding of gender‐related influences on surgical outcomes and enable the development of targeted interventions to improve patient care across different surgical fields.

Author Contributions

All authors contributed equally to this paper.

Funding

The authors received no specific funding for this work.

Consent

Informed consent was obtained from the patients to share their data for scientific purpose. All authors have read and approved the final version of the manuscript and Ali Talib Hashim (The corresponding author) had full access to all of the data in this study and takes complete responsibility for the integrity of the data and the accuracy of the data analysis.

Conflicts of Interest

The authors declare no conflicts of interest.

Transparency Statement

The lead author Ali Talib Hashim affirms that this manuscript is an honest, accurate, and transparent account of the study being reported; that no important aspects of the study have been omitted; and that any discrepancies from the study as planned (and, if relevant, registered) have been explained.

Hasan G. A., Raheem H. Q., Hammood M. M., et al., “Gender‐Based Analysis of Perioperative and Early Postoperative Complications in Tubular Microdiscectomy for Lumbar Disc Prolapse: A Retrospective Comparative Study,” Health Science Reports 9 (2026): 1‐6. 10.1002/hsr2.71772.

Data Availability Statement

The data can be made available on reasonable request from the corresponding author.