Splenic rupture following prone lateral discectomy and arthrodesis: illustrative case

Abstract

BACKGROUND

The prone lateral approach to lumbar spine surgery is known to have a multitude of potential complications, including damage to neurovascular structures, surrounding viscera, and intra-abdominal structures near the surgical site. However, iatrogenic injury to the spleen following prone lateral lumbar discectomy and arthrodesis as a potential complication has not yet been described in the literature.

OBSERVATIONS

The authors present the case of a 71-year-old female with a history of L3–S1 laminectomy and L3–5 arthrodesis who underwent a prone lateral discectomy of L2–3 with arthrodesis of the endplates for chronic lower-back pain. On postoperative day 1, the patient developed hypotension unresponsive to pressor medications, significant abdominal pain, and anemia requiring 2 transfusions. Bedside ultrasound revealed free fluid in the abdomen. She then underwent an exploratory laparotomy for splenic injury.

LESSONS

Although rare, splenic rupture should be considered as part of the differential diagnosis for patients with hemodynamic instability after lateral surgical approaches to the lumbar spine. Any patient with evidence of hypotension, anemia, and/or abdominal pain following lumbar surgery should be evaluated for splenic injury with an abdominal computed tomography scan and considered for surgical intervention.

https://thejns.org/doi/10.3171/CASE23639

The prone lateral approach to lumbar spine surgery is known to be associated with numerous possible complications, such as damage to neurovascular structures, surrounding viscera, and intra-abdominal structures close to the surgical site. This case report represents the only documented instance of iatrogenic splenic rupture following a prone lateral lumbar discectomy and arthrodesis. We present the case of a 71-year-old female who underwent an exploratory laparotomy for progressive abdominal pain and hemodynamic instability, revealing splenic rupture 2 days after lateral discectomy of L2–3 with arthrodesis of the endplates.

Illustrative Case

A 71-year-old female, whose past medical history was significant for heart failure with reduced ejection fraction with an automated internal cardioverter-defibrillator, chronic atrial fibrillation on warfarin, endocarditis after mechanical mitral valve replacement, and chronic lower-back pain secondary to spinal stenosis and spondylosis, presented for evaluation of painful, progressive lower-back pain and neurogenic claudication. She first began having lower-back pain and bilateral lower-extremity weakness approximately 7 years earlier and underwent an L3–S1 laminectomy and L3–5 arthrodesis, which temporarily resolved her pain. She subsequently experienced a return of symptoms 5 years later, which progressively worsened. Approximately 2 years later, the patient was experiencing lower-extremity weakness and pain in the lower back, which she described as radiating along the posterior aspects of the bilateral lower extremities. Her symptoms were exacerbated by bearing weight, and she soon began to have difficulty with balance. These manifestations imposed severe limitations on her activities of daily living and quality of life. Conservative measures such as physical therapy, anti-inflammatories, and steroid injections failed to relieve her pain.

On physical examination, she was found to have decreased motor strength in flexion and extension of the hips and knees bilaterally. Sensory abnormalities were noted over the L2 and L3 vertebral dermatomes. She had normal hip adduction and abduction strength, along with normal great toe extension, ankle dorsiflexion, and plantarflexion strength. Anteroposterior and lateral radiographs of the lumbar spine demonstrated moderate and severe disc space narrowing with diffuse desiccation at L2–3 and L3–4, respectively. Imaging also revealed moderate to severe spinal canal stenosis of L2–3 and moderate bilateral facet arthropathy (Fig. 1). Given the patient’s symptom presentation, the failure of conservative management, and the severity of radiographic pathology, she was deemed to be a good candidate for surgical intervention.

FIG. 1.

A: Sagittal magnetic resonance imaging (MRI) of the lumbar spine showing an artifact from the interbody spacer at L3–4 (white arrow) and posterior paraspinal rods from L3 to L5 (white bracket). B: Axial MRI of the L2–3 disc space illustrating mild left facet arthropathy (arrowhead) without significant spinal canal stenosis or neuroforaminal narrowing. I = inferior; P = posterior.

Perioperative anticoagulation was necessary because of the patient’s cardiac history to mitigate her increased risk of thrombotic events. She was pre-admitted for weaning off warfarin and initiation of a heparin drip. She underwent a prone lateral discectomy at L2–3 with arthrodesis of the endplates and placement of a cage, plate, and 2 screws, under the guidance of the Medtronic Mazor Stealth navigation system (Fig. 2). During the procedure, the patient was placed prone, a left stab incision was made over the left posterior superior iliac crest where a tracker was placed, and intraoperative computed tomography (CT) was performed for navigation purposes. The incision site for L2–3 was mapped out using navigation and anatomical landmarks, and a retractor was docked to an arm attached to the bed frame. Once a good position was established, blunt dissection of the remaining fibers of the psoas muscle was performed, and the L2–3 disc space was identified. Bony arthrodesis was performed, and an 8-mm lordotic implant packed with demineralized bone matrix and cortical cancellous chips was placed into the interspace (Fig. 3). When the implant was confirmed to be in a good position, a plate and 2 screws measuring 35 mm were placed at the L2–3 vertebral body. Fluoroscopic images showed the implants to be in an excellent position (Fig. 4). Subsequently, the retractor blades were removed, and there was no evidence of bleeding. The patient was estimated to have lost 100 mL of blood and remained hemodynamically stable throughout and immediately after the procedure.

FIG. 2.

Intraoperative images showing the prone patient in the operating room with instrumentation inserted in the left flank at the L2–3 region (A). A lateral view of the procedure as the surgeon uses navigation to orient himself at the vertebral level of interest (B). A lateral view of the cage placed at the L2–3 intervertebral disc space (C).

FIG. 3.

Schematic demonstrating patient positioning and the relation of the spleen and its surrounding attachments to the surgical field.

FIG. 4.

Intraoperative anteroposterior (A) and lateral (B) fluoroscopic images demonstrating L2–3 interbody placement and fixation.

During the first 12 hours after spine surgery, the patient remained hemodynamically stable with clean, dry, and intact incisions, along with appropriate incisional pain controlled with analgesics. Later on postoperative day (POD) 1, the patient experienced persistent hypotension despite maximum phenylephrine administration. She was transitioned to norepinephrine because of an increasing heart rate and a failure to achieve a mean arterial pressure goal of 80 mm Hg. The patient’s hemoglobin decreased from 11 to 8.6 g/dL on POD1, for which 500 mL of 5% albumin and 1 unit of packed red blood cells (pRBCs) were administered. Overnight, she had worsening hypotension and mixed venous oxygen saturation, raising concern for cardiogenic shock. Both dobutamine and vasopressin were initiated in response to increasing pressor requirements. From POD1 to POD2, despite receiving additional units of pRBCs overnight, the patient’s hemoglobin dropped again from 8.6 to 6.4 g/dL. The patient reported new severe abdominal pain, and physical examination showed pallor and abdominal distention. This prompted a bedside ultrasound, which showed free fluid in the abdomen. Subsequent CT scanning of the abdomen demonstrated hemoperitoneum and a large splenic hematoma with possible active extravasation (Fig. 5). The acute care surgery team was consulted and performed an exploratory laparotomy on POD2. In total, 2.3 L of blood and clots were evacuated from the abdomen. The splenic capsule was noted to be ruptured, and a splenectomy was performed. The patient was observed in the surgical intensive care unit for 6 days postoperatively with no complications or hemodynamic instability. The heparin drip was bridged to warfarin, and the patient was discharged on POD11.

FIG. 5.

Axial (A) and sagittal (B) CT scans of the chest and abdomen with intravenous contrast revealing a large splenic hematoma measuring 11.1 × 7.3 × 13.3 cm and compressing the spleen medially. A = the patient’s anterior orientation; P = the patient’s posterior orientation.

Patient Informed Consent

The necessary patient informed consent was obtained in this study.

Discussion

Lumbar interbody fusion is a surgical procedure indicated for patients with unstable spinal segments that restores intervertebral height, sturdiness, and proper lordosis. Because of the aging population, the prevalence of interbody fusion surgeries has steadily increased in recent years. Interbody fusion procedures are suitable for patients with diverse spine pathologies including, but not limited to, spondylolisthesis, degenerative disc disease, spinal stenosis, and disc herniation.¹ During the operation, 2 or more vertebral segments are held together using screws, plates, and/or rods to maintain the vertebrae in position to allow for fusion over time.¹ There are several surgical approaches to interbody fusion that are well described in the literature, each with their own set of advantages and disadvantages. Currently, lumbar fusion procedures can be performed via 5 approaches: lateral, anterior, posterior, transforaminal, and oblique.

The prone lateral technique was developed as an alternative lateral approach to the more traditional technique in which the patient was placed in the lateral decubitus position. The lateral decubitus position has been associated with postoperative hip flexor weakness due to operative trauma from instrumentation and repositioning. The prone lateral approach is performed with the patient prone, which provides the surgeon the freedom to access the anterior column via the lateral view while simultaneously having access to the posterior spine without the need for repositioning.² There are several theories to explain why the prone lateral approach poses less neurological risk, one being that the position of the patient allows for greater extension at the hips, which shifts the psoas muscle posteriorly. Because of this tension on the muscle, the lumbar plexus also moves posteriorly, thus providing more access for instrumentation with less injury to the nerves innervating the lower extremities.²

This approach is not without its drawbacks and complications, however. Such outcomes include injury to vascular and neurological structures as well as surrounding organs.³ In a study evaluating the incidence of vascular complications associated with lateral interbody fusion approaches, results showed the risk to be about 0.056% per case and 0.029% per level treated. In these cases, the vessels at greatest risk of injury were the common iliac vein or artery and the abdominal aorta.⁴ While uncommon, gastrointestinal injuries can also occur in lumbar interbody fusion procedures. Iatrogenic splenic injury has been seen most after colonoscopies and in other surgical procedures such as upper gastrointestinal procedures, vascular operations involving the abdominal aorta, and gynecological operations.³ Spine surgery has been rarely reported to be a cause of iatrogenic splenic injury.⁵ This case of splenic rupture after lumbar spinal arthrodesis in a 71-year-old female represents an anomalous instance of iatrogenic splenic injury. Although the exact etiology of the splenic injury is uncertain, we suspect traction on the spleen and its adjacent viscera caused capsular tear.⁶ Understanding the anatomical attachments of the spleen can help to prevent potential injury and improve upon surgical techniques. It has been reported that traction on vessels and peritoneal attachments of the spleen is commonly implicated in splenic injury.

While thousands of splenectomies are performed each year, less than 1% are performed due to iatrogenic injury. The most common cause of iatrogenic splenic injury is splenic flexure mobilization during colonic surgery.⁷ This is due to traction on the splenocolic ligament, which connects the transverse colon to the inferior pole of the spleen. The ligament is important to consider when performing abdominal procedures not only because traction can cause splenic capsule tear but also because it contains branches from the left gastro-omental vessels, which can be injured during instrumentation.^{7, 8} Additionally, downward traction on the omentum, spleen, or colon produces splenic injury that can necessitate splenectomy. The phrenosplenic ligament is formed by layers of peritoneum that connect the spleen to the thoracic diaphragm; because of these attachments, the pull on the abdominal viscera during any abdominal procedure introduces the risk of avulsion or capsular tear. The final ligament that is important to mention in cases of splenic injury is the gastrosplenic ligament, which forms the attachment between the medial border of the spleen and the left curvature of the stomach. The gastrosplenic ligament envelops vascular branches from the short gastric and left gastro-omental arteries, which can also lead to trauma to the capsule or hematoma if traction is applied.⁸ The surgeons participating in the prone lateral procedure suspect that the splenic injury may have been attributable to instrumentation causing tension on the abdominal viscera and leading to strain on the gastrosplenic ligament and the splenocolic ligament.

Alternatively, avulsion of one of the vessels in the suspensory ligaments of the spleen may have caused intracapsular hemorrhage, which progressed to capsular rupture.⁹ To our knowledge, there have been no other reported cases of iatrogenic splenic injury resulting from a posterior lumbar spinal approach. Splenic rupture has been scantly reported in spine surgery, with most cases resulting from thoracoscopic spinal surgery.⁵ The spleen can be vulnerable to iatrogenic injury given its proximity to the thoracolumbar junction.¹⁰ Various cases utilizing the anterior approach at the thoracoabdominal level have demonstrated iatrogenic splenic rupture. Heyworth et al. reported a case of splenic injury after the anterior approach for a planned thoracolumbar fusion.⁹ A 44-year-old female with thoracolumbar kyphoscoliosis underwent the procedure and became hemodynamically unstable on POD1. An emergency laparotomy was performed, revealing a massive hematoma in the left parasplenic gutter and a bleeding short gastric artery in the gastrosplenic ligament. Splenectomy and ligation were performed, and the patient recovered. In 1983, Hodge and DeWald reported 2 similar cases of splenic injury after the anterior approach for planned staged anteroposterior fusions.¹¹ In one case, a 48-year-old female was found to have bleeding on the surface of the splenic capsule following blunt dissection of the peritoneum from the posterior gutter. In this case, the capsular tear was linked to the adhesions present because of the patient’s history of abdominal procedures. In the second case, a 46-year-old female developed acute abdominal pain and hypotension 9 days postprocedure. Paracentesis revealed frank blood, and a laparotomy showed complete avulsion of the spleen from the hilum, resulting in a 15-cm hematoma. Subsequent ligation of the hilum resulted in a full recovery. Utilization of the posterior approach has also demonstrated iatrogenic splenic rupture. Christodoulou et al. described a case of splenic rupture after the posterior approach in which an adolescent female with Marfan’s syndrome underwent posterior instrumentation and fusion for thoracolumbar scoliosis.¹² Four days postoperatively, intraperitoneal lavage was performed for persistent hemodynamic instability and abdominal dullness, revealing frank blood. Laparotomy revealed a contained intracapsular hematoma with two 1.5-cm capsular tears in the upper pole of the spleen, prompting a splenectomy.

In the reviewed literature, it was found that splenic injury was most often caused by traction of the peritoneum, ligaments, and/or adhesions, which lead to avulsion of a splenic vessel.^{9, 11, 12} Although there are alternative technical approaches to lumbar fusion surgery, our patient was not considered to be a good candidate for them because of her cardiac history. Cardiac complications are uncommon but well-reported unfortunate outcomes in spine surgery. A history of cardiac disorders has been reported to be a risk factor for cardiac complications following spine surgery, with anterior and posterior approaches associated with a higher risk of adverse cardiac events.^{13, 14} Furthermore, while the posterior approach to fusion procedures has a lower risk of vascular injury, it carries a greater risk cerebrospinal fluid leakage, an extended operative time, and implant subsidence.^{15, 16} Considering this patient’s medical and surgical history, the prone lateral approach was chosen to potentially mitigate the aforementioned risks because of its shorter operative time and hospital stay.

Observations

This report explains the medical course of an elderly female who underwent a prone lateral discectomy of L2–3 with arthrodesis of the endplates and experienced an iatrogenic splenic injury requiring a splenectomy on POD2. While anterior and posterior approaches to thoracolumbar surgery have been reported to result in iatrogenic splenic injury, such an outcome has not been associated with lateral lumbar spinal arthrodesis. This case represents a unique situation and should be used to educate both patients and healthcare providers on the potential risks of the lateral approach to spine surgery.

Lessons

The use of the prone lateral approach in lumbar interbody fusion is appreciated for its ability to improve lumbar lordosis, shorten total operating room time, and reduce the postoperative hospital stay.¹³ Unlike our patient who presented with symptoms on POD1, other reports of spine surgery have described the symptoms of acute abdomen and hemodynamic instability several days into the postoperative course.^{11, 12} Given the variability in presentation, we recommend close monitoring of patients for up to 2 weeks after lumbar spine surgery. Any abdominal complaints or hemodynamic instability should be addressed promptly with laboratory assessment, ultrasound or contrast CT scanning of the abdomen, and general surgery consultation. The incidence of iatrogenic splenic injury following lateral lumbar spine surgery is unknown; however, splenic injury is a potentially deadly complication that should be considered as part of the differential diagnosis for patients with hemodynamic instability following such procedures.

Disclosures

Dr. Verma reported personal fees for consulting from Medtronic outside the submitted work.

Author Contributions

Conception and design: Echevarria, Verma. Acquisition of data: Echevarria, Verma. Analysis and interpretation of data: Hershfeld. Drafting the article: Echevarria, Hershfeld, Arciero. Critically revising the article: all authors. Reviewed submitted version of manuscript: Echevarria, Arciero, Verma. Approved the final version of the manuscript on behalf of all authors: Echevarria. Administrative/technical/material support: Verma. Study supervision: Echevarria, Verma.

Correspondence

Alexandra Echevarria: Northwell Health NorthShore University, Manhasset, NY. aechevarria2@northwell.edu.