- The injection site should at least be 5 cm away from the navel.
- The injection needle angle should be varied within 30 degrees from the vertical position.
- It is best to use the limbs to administer injections rather than the abdominal wall.
Anterior lumbar interbody fusion (ALIF) is a frequently performed procedure in lumbar spine surgeries1. Several perioperative vascular complications have been reported, including direct venous or arterial injuries causing bleeding, thrombophlebitis, vasospasm, thrombotic occlusion of the iliac veins, inferior vena cava lacerations, retroperitoneal, and pelvic hematomas. The incidence of vascular lesions encountered during ALIF procedures varies from 0 to 15.6%2. Here, we report a very rare case of bleeding and subsequent formation of a massive subcutaneous abdominal wall hematoma caused by injury to one of the left deep inferior epigastric artery (DIEA) perforators at a subcutaneous heparin injection site. Written informed consent3 was obtained from the patient for publication of this case report and accompanying images. To best of the authors’ knowledge, this is the first reported complication in published literature following ALIF surgery.
Presentation of case
A 25-year-old man presented with a 3-month history of intractable lower back pain and left S1 sciatica and had been taking high doses of morphine and gabapentin. He had previously undergone a left-sided L5/S1 minimally invasive transforaminal lumbar interbody fusion (TLIF) at another institution to treat his L5/S1 discogenic lower back pain. His lower back pain and right S1 sciatica had resolved immediately after the initial surgery but then developed immediate and intense left S1 sciatica with a visual pain analogue score of 8/10.
During the physical examination, he was able to tiptoe, heel-walk, and squat, but his left straight leg raise had reduced to 40 degrees due to painful S1 tension signs. There was normal motor power on left ankle plantar-flexion but the deep tendon ankle reflex was absent. On deep palpation, tenderness was present in midline overlying the L5/S1 segment. Computed tomography and x-ray radiographs conducted in our hospital revealed many several iatrogenic complications associated with the TLIF procedure (Fig. 1). First, we found the right-sided L4/L5 facet joint had been violated by the medially placed L5 pedicle screw. Second, a long right L5 pedicle screw had breached the lateral cortex of the L5 vertebral body by 13 mm and almost entering into the left common iliac vein, while thankfully the patient did not appear to develop any vascular issues after the index surgery. Third, a medially placed left-sided S1 screw impinging the S1 nerve root in the lateral recess, and this would explain the severe left S1 sciatica that occurred immediately after the TLIF surgery. Lastly, there was an appearance of a delayed L5/S1 delayed union, which is not unusual at this early 3-month time point following TLIF surgery.
The patient attempted but failed conservative treatment options involving physiotherapy and facet joint injections. Because he continued with severe pain, the patient elected to undergo revision surgery. In the prone position and via the previous mini-open Wiltse posterior incisions, computer-assisted navigation was used to extract and confirm satisfactory repositioning of the L5/S1 pedicle screws. Then the patient was turned supine and a transverse incision followed by a left-sided retroperitoneal approach to the spine was performed, after which the TLIF cage at L5/S1 was removed with ease. Finally, the disk space and end-plates were prepared before insertion of a large Titanium ALIF cage containing bone graft. The ALIF cage was secured in situ using 3 locking screws (Fig. 2).
On the fifth postoperative, a rapidly expanding lump appeared at the subcutaneous heparin injection site in the patient’s left lower abdomen. The mass began to cause severe excruciating pain unresponsive to morphine analgesia. An urgent abdominal computer tomography angiography revealed a massive and tense subcutaneous abdominal wall hematoma measuring 186.4 mm long, 158.3 mm wide and 103.7 mm deep. There appeared to be suspicious extravasation from the “Z”-shaped left DIEA perforator (Fig. 3). The patient underwent an emergency hematoma evacuation with ligation of the vessel followed by local debridement and by washout with hydrogen peroxide, iodine, and copious saline solutions. The wound was closed in layers over a single large bore drain. Approximately 1000 mL of hematoma was drained. A follow-up Doppler ultrasound of the abdomen the following day revealed no further bleeding within the abdominal.
Intraoperative samples revealed no deep infection. The patient made a good recovery and was discharged 6 days later. The patient was treated with intravenously prophylactic antibiotics for 2 weeks, and further abdominal Doppler ultrasonography 1 week later revealed an organization of hematoma measuring about 5.48 cm×2.39 cm. At the 6-month follow-up, the patient was pain-free in his lumbar spine, the left leg sciatica has resolved completely, and the abdominal wall was soft and fully healed without any evidence of local hematoma recurrence.
A review of the literature was performed using PubMed, EBSCO, OVID, and Springer databases. Table 1 summarizes the list of cases detailing the diagnosis, management, and prognosis. The search criteria included publications within the last 20 years, containing at least 1 case per a report, using the following search terms of ALIF and hematoma. We only identified 3 ALIF reports, including 2 with retroperitoneal hematoma4,6 and 1 with abdominal wall hematoma5. Patients underwent either an evacuation or insertion of polyvinyl alcohol particles with metal coils to help control the bleeding, and all the outcomes were favorable.
Table 1 -
Summary of patients with hematoma following anterior lumbar interbody fusion in the literature.
|Deekonda et al4
|Thaler et al5
||Degenerative disk herniation
||Abdominal wall hematoma
||Polyvinyl alcohol particles and metal coils
|Amaral et al6*
||Lumbar degenerative diseases
*There is 1 patient with a hematoma in 87 anterior lumbar interbody fusion cases.
M indicates man; NA, not stated.
The ALIF approach allows for a comprehensive discectomy, less trauma to the spinal nerves and paraspinal muscles, and avoidance of the disadvantages of collateral tissue damage that occurs with primary and revision posterior approaches. Notably, ALIF is associated with a risk of vascular injury7. This case required a revision and for reasons stated above, the ALIF approach was primarily chosen for (a) ease of TLIF cage removal and (b) insertion of an ALIF cage with a large footprint to achieve optimal stability thereby enhancing interbody fusion success. However, there are specific risks such as an injury to the abdominal viscera and vascular injury as well as retrograde ejaculation in males8. Currently, the number of ALIF procedures undertaken in lumbar spinal surgery is increasing, and the incidence of vascular lesions can be as high as 15.6%6,9. However, none of these studies that enrolled a large number of patients have reported about epigastric vessel lesions. Although abdominal wall hematomas caused by injury to the abdominal epigastric arteries are common complications in laparoscopic procedures10–12, a massive subcutaneous abdominal wall hematoma at a heparin injection site, as seen in the present case, is considered a very rare complication in spine surgery13. We believe this is the first reported case of injury to the left DIEA perforator as an indirect consequence of ALIF surgery.
A retrospective study conducted on 19 patients from 1995 to 2007 reported that an injury to the deep inferior epigastric artery perforators is the most often iatrogenic and subcutaneous injections account for to 5% of these complications. Contrast-enhanced computed tomography, such as this case, is routinely used to successfully diagnose active bleeding and embolization is effective in controlling hemorrhage14. García-Jiménez et al15 reported a massive abdominal wall hematoma secondary to subcutaneous infusion of low–molecular-weight heparin. However, similar studies following ALIF surgery are rare. A case report by Thaler and colleagues has been published on a patient who suffered from the right and left DIEA injuries during the implantation of a stand-alone ALIF cage. They found that the insertion of divergent screws caused severe distension and iatrogenic rupture of the epigastric vessels5. Deekonda and colleagues reported a postoperative retroperitoneal hematoma in an ALIF patient consuming rivaroxaban for atrial fibrillation. This report added to the evidence on the risk of postoperative bleeding in patients taking novel oral anticoagulants4.
Our patient had no previous history of abdominal surgeries or infections that may have posed an increased risk to the abdominal vascular structures during ALIF surgery. We speculate that inadvertent preinjury to the left DIEA and/or one of its perforators occurred during the left-sided anterior retroperitoneal approach access and subsequent ALIF procedure. This may have resulted from his preoperative large body habitus causing access difficulties followed by visceral shear forces such as squeezing, pulling, and excessive traction by the retractor blades during implantation of the ALIF cage. Subsequent subcutaneous heparin administration at the left abdominal wall caused further injury to one of the left DIEA perforators and the arterial bleeding that ensued. Previous studies have mostly reported retroperitoneal hematomas instead of subcutaneous bleeding.
Concerning this complication, we would like to recommend 3 important options that must be considered during postsurgery subcutaneous heparin administration. First, the injection site should at least be 5 cm away from the navel, where the left DIEA perforators are most commonly distributed. Second, the injection needle angle should not be perpendicular to the abdominal wall but must be varied within 30 degrees from the vertical position to avoid direct injury to these vessels. And third, it is best to use the limbs to administer injections rather than using the abdominal wall particularly following after all forms of anterior lumbar procedures; notably ALIF oblique lateral interbody fusion surgeries.
To the author’s best knowledge, this is the first case report describing an injury to the left DIEA and one of its perforators following an ALIF procedure. Spine surgeons need to have detailed knowledge of the anatomical position of these vessels during ALIF surgery and be cognisant that this rare form of vascular injury can occur following administration of heparin injection to the anterior abdominal wall. Sites remote from the anterior abdominal wall must be considered at all times following anterior spinal procedures because the DIEA and perforator vessels are already at risk following the surgical approach.
Ethical approval for this study was provided by the London Bridge Hospital IRB Committee.
Sources of funding
Funding was provided by Beijing Natural Science Foundation (7204327), Capital’s Funds for Health Improvement and Research (2020-4-40916) and AOSpine 2019 Discovery and Innovation Award (AOSDIA2019-026).
All authors contributed to this manuscript.
Conflict of interest disclosures
The authors declare that they have no financial conflict of interest with regard to the content of this report.
Research registration unique identifying number (UIN)
Research registry UIN was 6036.
Khai Sing Lam.
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