The following sections describe applications for intelligent therapeutic system for the following Healthcare Professions :
Microwave Ablation Synergies with Surgical Procedures
In many cases, surgical resection remains the gold standard treatment in the curative treatment. However, some patients are not eligible for surgical resection due to a number of factors including:
- Inability to achieve complete resection
- Sufficient volume of the viable organ remaining after resection
- Tumor biological aspects
A range of treatment modalities have been used as alternatives to surgical resection:
- Laser ablation
- Radiofrequency ablation
- Microwave ablation
- Chemical ablation
- Transarterial embolization (TAE)
- Transarterial chemoembolization (TACE)
Ablation in its many forms is an attractive alternative treatment for patients unable to have a resection. Ablation has also been used as an adjunct to resection, with patients having the majority of the diseased-tissue burden resected, with remaining disease eradicated via ablation.
Patients often have liver tumors that are surgically unresectable because of either unfavorable anatomy or poor hepatic reserve. Therefore, ablative techniques have been widely integrated into the management options currently offered to these patients.
Microwave ablation offers many of the benefits of RF but has several advantages that result in improved performance near blood vessels. During RF ablation, the zone of active tissue heating is limited to a few millimeters surrounding the active electrode, with the remainder of the ablation zone being heated via thermal conduction.
Because of the much broader field of power density, microwave ablation results in a much larger zone of active heating. This larger heating zone allows for a more uniform tumor kill in the ablation zone, both within the targeted zone and next to blood vessels.
In contrast, RF ablation is limited by the increase in impedance with tissue boiling and charring, because water vapor and char act as electrical insulators.
The electromagnetic nature of microwaves make microwave ablations unaffected by this limitation. This allows the temperature to be driven considerably higher, resulting in a considerably larger ablation zone within a shorter ablation time.
Also, it’s been noted that selected patients with isolated hepatic metastases who undergo hepatic resection often develop new tumors. Therefore, the broad convection profile of thermocoagulation via microwave ablation makes microwave ablation more suitable for treating patients with larger hepatic metastases.
Renal and Adrenal Disease
Increases in cross-sectional imaging as a first-line investigation for many indications has resulted in the earlier detection of asymptomatic renal tumors that may have otherwise remained undetected. Clinicians feel obligated to treat the disease once it is detected.
The primary treatment of choice for renal and adrenal tumors remains resection.
However, given the morbidity and mortality associated with nephrectomy, less invasive treatment techniques are often sought for smaller and more indolent tumors.
The focused thermoablative properties of microwave ablation enables localized tumor destruction while preserving the uninvolved renal parenchyma. This ability to treat renal tumors while maintaining renal function makes microwave ablation of solitary renal masses an attractive option.
Microwave Ablation Synergies with Radiation Therapy
Because of poor cardiorespiratory reserve, the majority of patients with primary and secondary lung malignancies are not candidates for surgery. Conventional treatments for these patients include external-beam radiation therapy, with or without systemic chemotherapy.
However, in many cases, no treatment option is possible. It’s highly likely that the majority of these untreatable patients will incur at least one of the following complications will manifest itself during the course of the disease: pain, dyspnea, cough, hemoptysis, metastases to the central nervous system or musculoskeletal system, tracheoesophageal fistula, and obstruction of the superior vena cava.
Palliative care therefore should become an important part of treatment to improve the patient’s quality of life. Since many patients may have disease that is far too advanced for resection, newer alternatives such as percutaneous ethanol injection, embolization of bone tumor vasculature, and lung tumor microwave ablation may be a viable salvage modality, providing, at minimum, symptomatic relief to patients for whom conventional modalities fail.
Microwave Ablation for Outpatient Procedures
In Interventional Radiology, you strive to diagnose and treat various diseases using minimally invasive procedures. By providing alternatives to open surgery, as an Interventional Radiologist, you reduce risk, pain and recovery time for patients. However, you need the best tools for the many outpatient procedures you perform:
- Soft tissue ablation procedures
- Organ-directed therapies
- Vascular work
- Pain management
- Drainage catheters
- Port and PICC Line Placement
Limitations of RF Ablation
For tumor ablation procedures, many clinicians choose thermal RF ablation as a minimally invasive treatment option in non-operative patients, and debulking of diseased tissue. However, RF ablation is fundamentally limited by its heating mechanism.
Tissue temperatures during electrical conduction must be kept below 100 °C to prevent charring and a subsequent rise in electrical impedance which limits growth of the ablation zone. Also, low frequency radiofrequency (RF) ablation may be effective for small and more peripheral tumors, but the risk of treatment failure is higher for larger or centrally located tumors.
And, while thermal ablation is an increasingly attractive choice for the treatment of unresectable tumors in the lung, RF ablation has several technical limitations for treating lung tumors. High electrical impedance characterizes normal aerated lung tissue. This high impedance limits current flow, and decreases the amount of energy that can RF ablation can deposit. Less energy deposition leads to lower tissue temperatures, and smaller ablation zones, which ultimately increasing the risk of treatment failure.
RF ablation is also limited by an inability to heat charred or desiccated tissue and to overcome the heat sink effect of local blood flow.
Benefits of Microwave Ablation
In contrast, Microwave Ablation platforms provide safe, effective, economical and user-friendly therapeutic energy. The MedWaves microwave ablation systems do NOT require irrigation, cooling and return pads like the other products in the market.
- The microwave generator-controller includes important safety features such as precise temperature and power controls for predictable coagulation-ablation effects.
- Regular-predictable ablation-zone size and shape; unaffected by varying tissue electrical resistance and minimally affected by cooling blood flow.
- No return pads to cause extra burns.
- Minimum to no pain and no nerve-muscular reaction during energy application (no current flow).
Microwave Ablation makes Business Sense Today and in the Future
The U.S. healthcare industry is in the midst of a fundamental transformation, stemming largely from rising costs and inconsistent quality of care. Healthcare reform laws and economic pressures are causing a shift in focus from volume-based to value-based care.
Payers and providers continue to explore innovations that improve clinical outcomes and reduce costs, and Minimally Invasive Surgery (MIS) is one such innovation.
Minimally invasive procedures offer patients reduced pain and scarring, shorter hospitalization, and a quicker return to activities of daily living. Studies show that MIS is frequently associated with reduced rates of complications, mortality, and morbidity. The data also suggest that MIS is associated with cost benefits, likely due to reduced length of stay (LOS) and fewer complications. The potential net result of replacing open procedures with MIS is that both the payer and the provider could see improved outcomes and a more favorable cost structure.
In the United States, payers generally reimburse the provider based on the Medicare Severity Diagnosis Related Groups (MS-DRG) system. The MS-DRG system provides a single reimbursement for an entire inpatient hospitalization, accounting for diagnosis and procedures performed during the hospital stay. MS-DRGs provide higher reimbursement for procedures with complications and/or comorbidities, and major complications and/or comorbidities. Patients with significant comorbidities prior to the surgery or who experience complications during or after the surgery (prior to discharge) are assigned a complex DRG (cDRG).
Procedures assigned to a cDRG are reimbursed at a higher rate on average than those assigned to the corresponding noncomplex, or base, DRG. The implications of DRG assignment for the payer are important because cDRGs typically result in a substantially increased expense.
Minimally invasive surgery is associated with improved clinical outcomes and reduced costs. Studies show that procedures performed via a minimally invasive surgery (MIS) approach, such as microwave ablation, would be associated with fewer complex Diagnosis Related Group (cDRG) assignments and subsequently result in reimbursement savings.