Intercostal Artery Laceration after Adrenal Mass Cryoablation
Shantanu Warhadpande, MD1 Amber Liles, MD1 Daniel Kirkpatrick, MD1
1 Department of Vascular and Interventional Radiology, University of Michigan Medical Center, Frankel Cardiovascular Center, Ann Arbor, Michigan
Semin Intervent Radiol 2023;40:286-289
Address for correspondence Shantanu Warhadpande, MD, Department of Vascular and Interventional Radiology, University of Michigan Medical Center, Frankel Cardiovascular Center, 1500 E. Medical Center Drive, Room 5582, Ann Arbor, MI 48109-5868 (e-mail: Warhadps@med.umich.edu).
| Abstract Keywords - cryoablation - intercostal artery - hemorrhage | We present a case of a 69-year-old male with profound Cushing's syndrome and hypercortisolemia secondary to a cortisol-secreting adrenocortical carcinoma. Patient was not a surgical candidate and subsequently underwent a successful posterior approach tumor cryoablation. The procedure was complicated by a T11 intercostal artery injury and hemothorax. The detection of the culprit injury was almost immediate and the quick response time, and treatment of the injury via an intercostal artery embolization was critical to limiting the patient's morbidity and mortality. This case discusses the technical challenges of a posterior-approach ablation, the pitfalls to |
| - hemothorax | avoid, and the importance of attaining rapid hemostasis. |
Case History
We present a case of a previously healthy 69-year-old male with recurrent left lower extremity cellulitis and recent diagnosis of Cushing’s syndrome who initially presented to the emergency department with altered mental status and sepsis. During a full workup for his sepsis, he was found to have a 6.8-cm left adrenal mass concerning for adrenocorti- cal carcinoma. He was also found to have left lower extremity cellulitis complicated by necrotizing fasciitis. Patient under- went a left above-knee amputation (AKA) for source control. Subsequently, the patient had a prolonged hospitalization in the intensive care unit (ICU). From the time of admission and throughout his ICU stay, he was found to have hypercortiso- lemia resulting in profound Cushing’s syndrome. Despite initiation of osilodrostat and metyrapone, his cortisol levels remained >30 µg/dL (goal 10-20 µg/dL). The culprit was suspected to be the cortisol-secreting left adrenal mass. This hypercortisolemia had two significant consequences in this patient’s hospital course: poor wound healing and immunocompromise.
The poor wound healing resulted in delayed healing of his left AKA stump and the immunocompromised state resulted in numerous respiratory and AKA stump infections. It was apparent that the patient’s hypercortisolemia and profound
Cushing’s syndrome was complicating recovery. He was evaluated by endocrine surgery multiple times for a left adrenalectomy, and each time he was deemed a poor surgical candidate. Consequently, with difficult to control serum cortisol levels, the patient entered a vicious cycle of recurrent respiratory infections, poor wound healing, and wound infections. The patient needed to have his serum cortisol levels reduced and medical management was insufficient.
After a long multidisciplinary discussion and with limited options remaining, interventional radiology offered a left adrenal mass cryoablation for the explicit goal of debulking the lesion and reducing the serum cortisol levels.
Procedure Description
After review of the cross-sectional imaging, a posterior- approach six-probe cryoablation was planned. The mass was nestled between the aorta medially, kidney/renal vessels inferiorly, spleen laterally, and pancreas/splenic artery ante- riorly (~Fig. 1a-c). Probe trajectories were planned accord- ingly, keeping all of these structures in mind. The 12th rib as well as the left kidney limited a caudal-to-cranial approach. Thus, several of the planned probe trajectories targeting the cranial and mid aspect of the mass were via an intercostal approach between left ribs 11 and 12. The trajectories of the remaining probes were subcostal. Preprocedurally, it was
Issue Theme Complications in IR; Guest Editors, Matthew Niemeyer, MD and Ketan Y. Shah, MD
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acknowledged that the caudal aspect of the mass was unlikely to be treated given its location anterior to the kidney. Given that the goal of the procedure was debulking, this was an acceptable limitation.
On the day of the procedure, general anesthesia was administered. Per endocrinology recommendations, prein- duction steroids were administered (100 mg intravenous hydrocortisone). Phenoxybenzamine, phentolamine, esmo- lol, and propranolol bags were prepared and ready in the room in case of an intraprocedural adrenergic crisis.
As planned, using CT fluoroscopy, suitable windows and trajectories to the lesion were identified, avoiding the ribs and avoiding any critical structures in the retroperitoneum (~Fig. 1a-f). The probes targeting the cranial and mid aspect of the mass were introduced in the left 11th/12th rib inter- space and advanced into the lesion. The remainder of the probes were introduced subcostally and positioned within the lesion. Once the subcostal probes were placed, just below the 12th rib, a repeat CT was performed. Sagittal reconstruc- tions demonstrated a few concerning findings. First, the caudal-most probes that were placed subcostally appeared to be flush against the inferior aspect of the 12th rib (~Fig. 2a). Second, the probes placed within the 11th/12th interspace appeared to transgress the parietal pleura, though no pneumothorax was identified on the lung window (~Fig. 2b). The caudal-most aspect of the mass was unable to be targeted safely given the interposed kidney.
As the probes were satisfactorily positioned within the lesion, the decision was made to proceed with the ablation. A total of six probes were placed and cryoablation was per-
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formed (10-minute freeze cycle, 5-minute thaw cycle, 10- minute freeze cycle, 5-minute active thaw cycle). The abla- tion zone appeared satisfactory on the final CT, prior to probe removal. The critical structures surrounding the mass were noted to be uninjured. At this point, all cryoprobes were removed from the body and a final contrast-enhanced CT (venous phase) was obtained with the patient still in the IR suite.
On the completion CT, a small hematoma with linear contrast extravasation was noted in the 11th/12th interspace (Fig. 3a). The patient was still stable at this time and, as the CT was obtained in the venous phase, the decision was made to wait and follow the patient clinically. However, as soon as the anesthesia team began the extubation process, the
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patient became hypotensive. Additionally, it was becoming more difficult to ventilate the patient. A CT angiogram was immediately performed. This confirmed the suspicion: there was arterial extravasation originating from the intercostal artery in the left 11th/12th interspace. Patient also had a large, new left hemothorax (~Fig. 3b). Venous blood gas demonstrated hemoglobin of 7 (down from 10 preprocedurally).
Massive transfusion protocol was initiated. Patient subse- quently underwent a successful coil embolization of the culprit T11 intercostal artery. The T10 intercostal artery was also prophylactically embolized with coils. A 14-Fr chest tube was placed in the left pleural space with removal of 750 ml of blood. Thereafter, patient’s respiratory status and hemodynamics improved and patient was transferred back to the ICU in stable condition.
Despite the intraprocedural complication, the cryoabla- tion was a clinical success. Patient’s cortisol levels normal- ized to the 10 to 20µg/dL 1 week later. His left AKA stump healed uneventfully thereafter and he had no further infec- tions requiring readmission to the ICU. He was eventually discharged to a rehabilitation facility and then home.
Discussion
Over the last two decades, thermal ablation of an adrenal mass has become a more accepted treatment approach in nonsurgical candidates.1,2 Radiofrequency ablation, micro- wave ablation, and cryoablation have all been described in the treatment of adrenal lesions.3 The feared common com- plications during and after an adrenal mass ablation are usually related to the uncontrolled release of catecholamines and the resultant adrenergic crisis. As such, preprocedural and intraprocedural availability of a-blockade agents is highly recommended.2-4 There is also a risk of postablation adrenal insufficiency and preprocedure administration of pulse-dose steroids should be considered along with a steroid taper postprocedurally.5 Close communication and
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perioperative consultation with the endocrinology team is highly recommended before adrenal ablations.
Thermal ablation of retroperitoneal structures such as the kidney or adrenal gland routinely demands a posterior approach. As with any ablation, probe trajectory and inser- tion should account for any organs or vessels both around the ablation target and in the path of the probe. When possible, avoidance of the intercostal space is preferable. In situations where the intercostal space is difficult to avoid, such as in the case presented here, every attempt should be made to remain low in the interspace.
In procedures requiring a posterior approach, it is recom- mended to place the patient in an ipsilateral lateral decubitus position to take advantage of the lung hypoinflation on the dependent side and to minimize the risk of pleural trans- gression or lung injury. The pleural reflection is usually two rib spaces below the visceral pleura. It must be assumed that any puncture in the intercostal space at any level is trans- gressing the parietal pleura. If a patient develops a new pleural effusion after a puncture in the intercostal space, the operator should have a high degree of suspicion for a biliary effusion (if accessing the liver), hemothorax, uro- thorax (if accessing the collecting system), or pneumothorax.
In this case example, the decision was made to keep the patient prone given the high number of probes that would be required for the ablation and the ergonomics associated with this many probes with the patient in the CT gantry. Meticu- lous care was taken during the cryoprobe placement, ac- counting for the major retroperitoneal organs and vessels. Using CT fluoroscopy, “safe” windows to the lesion were identified from a posterior approach. Four of the cryoprobes were placed in the T11/T12 interspace; two were placed directly above the 12th rib and two were placed in the middle of the interspace.
Once the probes were placed, a repeat CT was performed. The ablation zones were calculated and the surrounding retroperitoneal structures were taken into the account. The genitofemoral nerve is an at-risk structure in the lumbar retroperitoneum, as it courses along the anterior aspect of the psoas muscle. Injury to this nerve can result in anesthesia
of the anterior thigh and the genital area (mons pubis in females, scrotum in males). In this case, the genitofemoral nerve, the left kidney, pancreatic tail, and splenic vessels were all safe from the calculated ablation zones. As no surrounding retroperitoneal structures were at risk, no protective strategies were employed. If there had been concern for the ablation encroaching on critical structures, hydrodissection with warm dextrose 5% in water (D5W) or pneumodissection could have been performed to buffer structures that needed to be protected from the thermal energy.
While the retroperitoneal structures appeared safe from the calculated ablation zones, there was concern for T12 intercostal artery injury given that the subcostal probe was flush against the inferior aspect of the T12 rib. Additionally, parietal pleural transgression was noted, but no pneumo- thorax was identified. The cryoablation proceeded unevent- fully and the expanding ice ball did not encroach on any critical structures.
The concern for an intercostal artery injury was highest at T12; however, the intercostal artery that was actually lacer- ated was the T11 intercostal artery. While the common teaching is that the intercostal neurovascular bundle is flush against the inferior aspect of the rib, this may not always be the case, especially in the posterior aspect of the interspace. The course of the intercostal artery in the posterior intercos- tal space is unpredictable, with the artery frequently looping into the middle of the interspace.6
One strategy to avoid the intercostal artery in the poste- rior interspace is by performing an intraprocedural CT angiogram once the patient is positioned and prior to traversing the intercostal space. This would allow for clear delineation of the intercostal artery as well as any other vessels in the planned trajectory. Another option is to perform tract ablation (a feature in some of the newer thermal ablation probes) to cauterize any vessels while removing the probes.
An important lesson gleaned from this case is to bear in mind the possibility of an intercostal artery injury whenever access in the interspace is obtained. It is critical to have a high degree of suspicion for an intercostal artery injury and a low threshold to intervene to reduce morbidity and mortali- ty. In the presented case, the intercostal artery injury was suspected as soon as the contrast-enhanced CT (after remov- al of all probes) was performed, mere minutes after the removal of the probes. When the patient demonstrated signs of hemorrhagic shock, the prompt decision was made to
perform an intercostal angiogram and embolization. The expedited detection, response-time, and treatment of the underlying problem were likely what contributed to the patient’s survival and eventual clinical success of the adrenal mass cryoablation.
Conclusion
In this case, we presented a patient who underwent a posterior-approach multiprobe cryoablation of a cortisol- secreting adrenal tumor. The procedure, while a technical and clinical success, was complicated by laceration of the left T11 intercostal artery resulting in hemorrhagic shock and a hemothorax. This necessitated urgent and successful embo- lization of the culprit artery and a left chest tube placement.
The course of the intercostal artery in the posterior interspace is variable and, despite the classic teachings, does not always course along the inferior aspect of the rib. The artery can-and does-loop into the middle of the interspace. When a planned trajectory into the retroperito- neum necessitates a posterior interspace approach, consider obtaining an intraprocedural CT angiogram prior to inter- space access to delineate-and avoid-the intercostal artery. Additionally, have a low threshold for concern if the final CT demonstrates a new pleural effusion and be prepared to intervene.
Conflict of Interest None declared.
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