INTRODUCTION
Posterior lumbar spine fusion is one of the most frequently performed surgical procedures within the field of spinal surgery [1]. The application of pedicle screws in spinal surgery started in the 1950s and 1960s [2].
The most common complications associated with these surgeries include infection at the surgical site, new neurological deficits, cerebrospinal fluid leaks, pulmonary complications, venous thromboembolism, and issues related to implants [3,4].
Intra-abdominal complications following posterior lumbar surgeries are associated primarily with vascular injuries, which occur in less than one percent of cases, as well as bowel perforation [5,6].
One of the uncommon complications is appendicitis. The diagnosis of acute appendicitis is primarily clinical, supported by laboratory and imaging findings, which are summarized in the Tables 1-3.
Previous studies have identified several intra-abdominal complications, including vascular injuries, bowel injuries, ureteral injuries, Ogilvie syndrome, and pancreatitis, among others. Although the incidence of these complications is quite low, failure to diagnose them early can lead to significantly high morbidity and mortality rates. In this study, we present a case of acute appendicitis that developed immediately following lumbar fusion surgery.
CASE PRESENTATION
A 55-year-old Persian woman presented with lower back pain radiating to her right leg, accompanied by severe tingling sensations (paresthesia) in the same limb. During the physical examination, she was found to be markedly obese, with a body mass index of approximately 35 kg/m2. Muscle strength in her left leg during dorsiflexion was rated at 4 out of 5 points, whereas other physical findings were unremarkable.
Radiological evaluations utilizing magnetic resonance imaging have revealed lumbar canal stenosis at the L3–5 levels, along with spondylolisthesis at L3–4 (Figures 1, 2). To further assess the patient's condition, electromyography and nerve conduction studies were performed. Based on the patient's reported symptoms, thorough physical examination, and the results from these paraclinical tests, a recommendation for surgical intervention has been proposed to address the underlying issues and relieve the patient's discomfort.
The patient underwent L3‒L4‒L5 bilateral laminectomy, which included posterior decompression, discectomy, and posterior fusion with pedicle screw placement, as well as transforaminal lumbar interbody fusion (TLIF) at the L3–4 level (Figure 3). The surgery lasted approximately 140 minutes and was completed without any complications. All screws were successfully placed on the first attempt, and there was no abnormal bleeding, with a total intraoperative blood loss of 400 mL. The patient did not experience any hypotension during the procedure.
After surgery, the patient underwent a neurological examination in the recovery unit, which was unchanged from the preoperative evaluation. The patient was then transferred to the ward upon achieving full consciousness and hemodynamic stability.
Six hours after surgery, a complete blood count test indicated a hemoglobin (Hb) level of 12.3 g/dL, reflecting a 2-unit drop consistent with intraoperative blood loss. Leukocytosis was also observed, with a white blood cell (WBC) count of 18,000, 75% of which were neutrophils. Twelve hours following the surgery, the patient began experiencing abdominal pain in both the left and right lower quadrants, which gradually worsened. Throughout this period, the patient's hemodynamic status remained stable.
An abdominal and pelvic ultrasound showed no pathological findings or free fluid; however, the patient's obesity complicates the investigation. After consulting with the general surgeon, conservative management was recommended.
The day after surgery, the patient continued to experience abdominal pain despite receiving analgesics. The patient's Hb level decreased by one unit, and the WBC count increased to 21,000. A repeat consultation with the general surgeon was conducted, and an abdominal and pelvic computed tomography (CT) scan with and without intravenous contrast was recommended.
The noncontrast CT scan confirmed that the screws and TLIF were properly placed, with no signs of intraperitoneal or retroperitoneal hemorrhage or free fluid. However, contrast-enhanced CT could not be performed because of the patient's agitation and pain.
In light of the clinical scenario, exploratory laparotomy was advised. During the laparotomy, no free fluid or hemorrhage, either intraperitoneal or retroperitoneal, was found, nor was there any damage or necrosis of the ileum or colon. However, acute appendicitis with a fecalith in the lumen was identified, and an appendectomy was performed. In the pathology report, a macroscopic examination of the appendix revealed a fecalith within the lumen upon sectioning. Microscopic examination of the appendix sections showed infiltration of neutrophils in the mucosa, indicating acute inflammation.
Following laparotomy, the patient's abdominal pain significantly resolved, leukocytosis decreased, and Hb levels stabilized. The patient was discharged in good condition 2 days after the appendectomy.
Informed consent was obtained from the patient who participated in this study.
DISCUSSION
The occurrence of acute appendicitis immediately following posterior lumbar fusion (PLF) surgery is an unusual and noteworthy clinical event. Acute appendicitis is a common surgical emergency, but its presentation in the immediate postoperative period of an unrelated major surgery, such as lumbar fusion, is rare and poses diagnostic challenges [7].
In the clinical presentation, the patient experienced worsening abdominal pain following surgery, which is a significant symptom of acute appendicitis. However, the initial evaluation did not explicitly detail the pain's location or characteristics, such as whether it migrated to the right lower quadrant. The absence of nausea, vomiting, or fever does not exclude appendicitis, as these symptoms can be masked in postoperative patients [8].
In terms of the physical examination, no specific signs were noted during the abdominal assessment, including tenderness, rebound tenderness, or guarding.
When it comes to laboratory findings, both leukocytosis and elevated C-reactive protein levels serve as important indicators that can be seen in postoperative patients as well as those suffering from appendicitis [9]. Notably, during the patient's hospital stay following surgery, we observed an upward trend in leukocyte counts, which would have supported the diagnosis. It is important to note that a decrease in Hb is not a typical blood test finding associated with acute appendicitis. However, this patient exhibited a slight drop in Hb, likely resulting from mild blood loss or hemodilution, rather than being directly linked to appendicitis itself [10].
In the imaging findings section, the intraoperative diagnosis was confirmed during the exploratory laparotomy, which revealed acute appendicitis with the presence of a fecalith. Preoperative imaging, however, failed to show any pathological findings [11].
In the context of our case, the immediate postoperative period following lumbar fusion surgery involves significant physiological stress and potential immunosuppression, which may predispose patients to infections, including appendicitis. Wong et al. [12] discussed the importance of considering atypical presentations of appendicitis, especially in patients with a history of abdominal surgery, as recurrent or atypical abdominal pain should not be dismissed.
There are no case reports specifically about acute appendicitis following TLIF, but a retrospective study by Lee et al. [13] evaluated the incidence and risk factors for 30-day unplanned readmissions after elective PLF surgery. This study revealed several significant postoperative complications, including wound complications, pulmonary embolism, deep vein thrombosis, sepsis, and urinary tract infections, with wound complications being the most prevalent (odds ratio, 27.6; 95% confidence interval, 13.9–54.8; p=0.0001). Although acute appendicitis was not specifically mentioned in this study, the findings underscore the importance of vigilance for a range of complications in the postoperative period.
The patient was positioned prone during the lumbar fusion surgery. Prolonged compression of the lower abdomen in this position could theoretically contribute to ischemic issues, but this is speculative and not well documented in the literature. The case report does not provide evidence of direct causation.
The pathophysiology of acute appendicitis in the context of recent spinal surgery is not well documented. It is challenging to definitively determine whether the appendicitis was a consequence of the lumbar fusion surgery or an incidental development. However, factors such as postoperative immobility, changes in intra-abdominal pressure, and alterations in gastrointestinal motility may contribute to the development of appendicitis. Additionally, the stress response to surgery and potential alterations in immune function may predispose patients to inflammatory conditions.
The management of acute appendicitis in the postoperative setting requires prompt surgical intervention. Laparoscopic appendectomy is the preferred approach because of its minimally invasive nature and favorable outcomes, as supported by Choi et al. [14], who reported successful laparoscopic management of stump appendicitis without the need for open conversion. This approach minimizes additional surgical trauma and promotes faster recovery, which is crucial in patients recovering from major surgeries such as lumbar fusion.
In light of this, clinicians should remain vigilant for complications such as acute appendicitis in patients who have undergone lumbar spine surgery. Addressing worsening abdominal pain promptly—particularly in high-risk populations such as those with obesity—can significantly improve patient outcomes. Implementing tailored management strategies can improve safety and recovery. Collaboration with specialists and timely evaluations, along with proactive imaging, are vital for the early identification of potential issues.
Furthermore, promoting weight loss through dietary modifications and exercise is essential for minimizing future surgical risks and enhancing overall health. Future research should aim to investigate the relationship between lumbar spine surgery and acute appendicitis, especially among obese individuals. It is crucial to assess effective diagnostic and treatment strategies, including imaging options such as ultrasound and CT scans. Longitudinal studies should explore long-term outcomes for patients who develop appendicitis postsurgery, with a focus on recurrence rates, functional outcomes, and quality of life. Identifying risk factors and developing predictive models can help mitigate complications. Ultimately, establishing evidence-based guidelines for managing high-risk patients, particularly those with obesity, is essential for improving patient outcomes.
One limitation of this case report is the rarity of acute appendicitis as a complication of lumbar spine surgery, which may limit the broader applicability of these findings. The single-case design does not allow for definitive conclusions regarding the relationship between surgery and the onset of appendicitis. Additionally, patient obesity may introduce confounding factors that influence the risk of postoperative complications. The lack of long-term follow-up data further restricts a comprehensive understanding of this case's implications.
CONCLUSION
Given the infrequency of acute appendicitis following PLF, clinicians must maintain a high index of suspicion when patients present with atypical abdominal symptoms after surgery. Early recognition and prompt intervention are critical for preventing serious complications, such as perforation and peritonitis. This case report underscores the importance of careful monitoring and thorough differential diagnosis in high-risk individuals, particularly obese patients, following lumbar fusion surgery. Timely diagnosis is essential to optimize patient outcomes while enhancing our understanding of this rare complication. Further investigation is necessary to clarify the mechanisms and risk factors involved.
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