Management of Massive Flank Hernia After Lateral Lumbar Fusion: Preoperative Botulinum Toxin Injections and Open Repair – A Case Report

Introduction

Incisional flank hernias represent a significant complication after spinal surgeries that utilize the direct lateral interbody fusion (DLIF) or extreme lateral interbody fusion (XLIF) approaches. The DLIF and XLIF approaches were developed to avoid performing spinal interbody fusion through the anterior approach, due to the risk of iatrogenic vascular injury [1], and they have been increasing in popularity because of expanding indications [2,3]. Six case reports and 1 retrospective study have been published on flank hernias after lateral interbody fusion procedures, totaling 21 flank hernia cases, making them extremely rare [4–10]. The National Institute for Health and Care Excellence (NICE) guidelines for lateral interbody fusion, based on a systematic review and meta-analysis of 237 articles, do not even mention flank hernias as one of the complications of lateral interbody fusion, demonstrating their rarity [11].

Flank hernias after lateral interbody fusion usually occur within 1 year after surgery and can cause significant morbidity and decreased quality of life for patients [10]. Additionally, there is potential for the incarceration of bowel contents within the hernia, which can be life-threatening, in up to 10% of flank hernias [12]. The development of flank hernias in patients who have undergone DLIF or XLIF is likely due to myofascial dehiscence, becoming a technically challenging problem to repair in the future. It can also be accompanied by muscle denervation during the surgical approach, causing anterior abdominal bulging [10]. In combination with the increasing annual rate of lumbar spinal fusion being performed [13], the rate of incisional flank hernias occurring secondary to lateral interbody fusion approaches will likely increase, necessitating general surgeons to have an armamentarium of techniques for repairing incisional flank hernias.

While many published reports describe open flank hernia repairs [14], only 21 flank hernia repairs have been reported after patients underwent lumbar interbody fusion [4–10], and there are no published reports of open massive flank hernia repairs utilizing preoperative botulinum toxin injections. In this report, we aim to present the application of preoperative botulinum toxin injections as a strategic approach to enhance the secure re-approximation of fascial layers and reduce recurrence rates in open flank hernia repairs. The utilization of pre-operative botulinum toxin offers the ability to induce tissue laxity, thereby establishing a more stable foundation for hernia repair surgeries. Therefore, we sought to publish this technique to provide surgeons with an innovative method for preoperatively treating patients with massive flank hernias, to facilitate successful outcomes after open hernia repair.

Case Report

A 75-year-old man presented to the clinic due to left lower anterior abdominal wall and left lower back bulging and discomfort for 5 months. The symptoms began after a lateral lumbar spinal fusion from L2 to L4 performed on April 22, 2022. Magnetic resonance imaging obtained at an outside institution demonstrated a large left lower incisional flank hernia with significant loss of domain. The patient denied any fevers, chills, nausea, vomiting, or changes in bowel or bladder habits. His medical history included coronary artery disease status after placement of 2 cardiac stents (2019), stage 4 chronic kidney disease, hypertension, major depressive disorder, hepatitis C, and pancreatitis. His surgical history included abdominal wall hernia repair and neobladder reconstruction surgery (2008). The patient underwent neobladder reconstruction surgery due to urothelial cell carcinoma, which was causing obstruction of the right kidney. Tissue from the terminal ileum was used in the bladder reconstruction. Neoadjuvant chemotherapy was administered to the patient; however, he declined adjuvant chemotherapy. At the time of hernia repair, there was no evidence of recurrent disease. Relevant social history included being a former smoker (he quit in 2014). There was no pertinent family history. Vital signs were within normal limits. Physical examination revealed a soft abdomen with a large diffuse area of bulging in the left lower abdominal wall and a left posterior lateral flank reducible bulge consistent with an incisional flank hernia (Figure 1). His workup included a computed tomography (CT) scan, which showed a large fat-containing left posterolateral abdominal wall hernia (51.3×69.2 mm; Figure 2), with no evidence of bowel within the defect and a previous abdominal wall repair with mesh. The patient was scheduled for lateral abdominal wall botulinum toxin injections prior to surgery. The patient received 150 units of Botox. The Botox solution was divided into 3 equal amounts and placed into 3 syringes. A maximum sterile barrier technique was used. Using CT and ultrasound, three 20-gauge needles were placed in the left transversalis and internal and external oblique muscles. Botox solution was injected into each muscle. Negative aspiration was performed prior to injection to avoid intravascular infiltration. There were no immediate complications observed after the procedure.

Four weeks later, the patient was taken to the operating room for an open massive left flank hernia repair with mesh. The patient was placed under general endotracheal anesthesia and underwent an erector spinae block. Afterward, the patient was placed in a right lateral decubitus position, and the operating table was slightly flexed to give complete exposure and visualization of the patient’s left flank. The old left flank surgical scar was used as the incision site. The soft tissue was mobilized with the use of cautery and blunt dissection until the anterior and posterior body wall and the paraspinous muscles were visualized. A large hernia sac was dissected out circumferentially. The fascia was exposed over the external obliques throughout the whole defect for clear visualization of the body wall. The hernia sac was reduced using sharp, blunt dissection and cautery until exposure of the underside of the body wall was achieved (Figure 3).

The transversus abdominus and obliques were mobilized by creating myofascial flaps. The defect measured approximately 4.5×4.5 cm, for which a Ventralight ST Mesh (Becton Dickinson, Franklin Lakes, NJ, USA) measuring 10×15 cm was used. The mesh was placed under all layers of the abdominal wall, including the paraspinous muscles (Figure 4). The mesh was anchored using a horizontal mattress pattern with #1 Prolene sutures (Ethicon, Cincinnati, OH, USA) in a posterior to anterior superior direction. Vistaseal (Ethicon) was sprayed over the mesh to diminish any dead space. The dermis was closed using interrupted 2-0 Vicryl suture (Ethicon). The skin was closed with a running subcuticular Monocryl suture (Ethicon) and was sealed with Dermabond (Ethicon; Figure 5).

The patient tolerated the procedure well. He received oral narcotics with a multimodal pain regimen and reported pain to be well controlled. He was discharged home on postoperative day 2 and instructed to do no heavy lifting and remain consistent with using the abdominal binder. He was scheduled for a 2-week postoperative follow-up, during which, he mentioned the pain had been improving. However, he endorsed operative site swelling. On physical examination, there was left flank surgical site swelling, consistent with a postoperative fluid collection or seroma. The patient was scheduled for 4-week follow-up, where he had complete resolution of his seroma, postoperative pain, and discomfort, as well as bulging in his left lateral abdominal wall (Figure 6). Repeat imaging with CT at 2 months postoperatively showed no evidence of the patient’s prior hernia defect.

Discussion

There has been a rapid increase in the popularity of minimally invasive techniques, XLIF being one of them [15]. More than 20% of spinal fusions being performed in the United States utilize the XLIF or DLIF approach [16,17], while 14% of spinal fusions being performed in the United Kingdom utilize the XLIF or DLIF approach [18]. While there is a higher utilization of the transforaminal lumbar interbody fusion (40.4%), posterior lumbar interbody fusion (28.1%), and anterior lumbar interbody fusion (15.8%) approaches in the United Kingdom [18], the XLIF and DLIF procedures are the newest approaches and are gaining utility. Most spine surgeons use the XLIF or DLIF approach (58.1%), although not for many of their cases, with most spine surgeons acknowledging that patient-specific factors affect the approach they use [18]. Given the rising adoption of the XLIF and DLIF approaches, an increasing number of patients have the potential to develop incisional flank hernias that will require surgical repair.

Adequate fascial and muscular closure is paramount when performing a lateral approach lumbar spinal fusion. This step becomes more critical in patients with pre-existing chronic kidney disease and hypertension, such as ours, as wound healing can be further delayed [19]. To achieve suitable wound closure, certain points must be considered, such as recruiting richly vascularized tissue, separating fascial compartments, and creating a tension-free wound [20]. Surgical site infections and wound dehiscence remain among the most common postoperative complications in this type of surgery [21–23]. However, with the increasing rates of lumbar spinal fusions being performed annually [13], it is important to consider other complications, such as secondary incisional flank hernias.

Moreover, proper wound closure is equally essential in hernia repair, as failure to achieve adequate fascial, muscular, and skin closure, along with mesh reinforcement, can result in various surgical site complications, including incisional flank hernia recurrence, infection, flap necrosis, and seroma formation [24].

Minimally invasive approaches are feasible options for flank hernias. However, they come with their limitations, such as the potential for visceral injury when attempting to obtain good visualization of the defect, the challenge of navigating large pieces of mesh using laparoscopic or robotic approaches, and limited options for mesh anchoring [25]. The open approach to massive flank hernia repairs allows for better visualization and easier manipulation of myofascial flaps [26]. Unlike laparoscopic interventions, the open approach addresses the visible bulge aspect of the defect, which is often a source of discomfort for patients. Using an open approach allows for more effective re-approximation of the fascial components of large lateral flank hernia defects [26]. With this objective, the use of botulinum toxin in the preoperative management of flank hernia repair can be beneficial in the process of re-integrating myofascial flaps.

The application of botulinum toxin in the preoperative management of hernia repairs was first reported in 2009 [27]. Since then, it has been used in many hernia repairs. Clinical studies have shown that the administration of preoperative botulinum toxin injections is associated with high rates of fascial closure and reduced recurrence rates [28]. However, there are no published reports on the use of preoperative botulinum toxin in the repair of massive lateral flank hernias. The bridging technique represents a surgical approach used by surgeons to address challenging cases of large hernia repairs. This method involves placing mesh to span the entire hernia defect, without involving closure of the fascial layers. It has been noted that due to the absence of reinforcement from fascial layer closure, this technique has been associated with higher rates of surgical site occurrences, when compared with outcomes observed with hernias repaired with primary fascial closures [32]. Given the positive outcomes of preoperative botulinum toxin use in abdominal wall reconstruction [29], alongside the successful closure of our patient’s massive flank hernia defect without the requirement for the bridging technique, we propose that the implementation of botulinum toxin injections in the preoperative management of massive lateral flank hernia repair has the potential to yield enhanced fascial closure rates. This approach could potentially minimize the necessity for the bridging technique and decrease recurrence rates and seroma formation. We recommend further investigation to evaluate the potential benefits of botulinum toxin as an adjunctive therapy in the management of this demanding hernia subtype.

Another complication that can mimic an incisional flank hernia is abdominal wall paresis, which can develop 2 to 4 weeks postoperatively in approximately 2% of patients after undergoing XLIF or DLIF [30]. However, abdominal wall paresis is typically transient and resolves in most patients by 6 months after surgery [30]. Abdominal wall paresis can be differentiated from more serious complications, such as an incisional flank hernia, by using a CT scan. Other complications that can occur during XLIF or DLIF requiring the expertise of a general surgeon include bowel perforations, although these are rarely reported in the literature and require further study to determine their incidence [31].

Conclusions

The patient experienced complete resolution of pain and abdominal wall defect. The preoperative botulinum toxin injections aided in enhanced myofascial flap and skin closure. The use of pre-operative botulinum toxin injections prior to massive lateral flank hernia repair is recommended.