What labs are required prior to InterStim (Interstim, sacral nerve stimulation) surgery?

Preoperative Laboratory Testing for InterStim Surgery

For patients undergoing InterStim (sacral nerve stimulation) surgery, routine preoperative laboratory testing is not required unless specific risk factors or comorbidities are present. 1

General Approach to Preoperative Testing

InterStim surgery is considered a low-risk surgical procedure that typically involves minimally invasive techniques. According to evidence-based guidelines, preoperative testing should be guided by the patient's clinical history, comorbidities, and physical examination findings rather than performed routinely 1.

Basic Laboratory Tests to Consider Based on Risk Factors:

1. Complete Blood Count (CBC)

   • Only indicated for patients with:
     • Diseases that increase risk of anemia
     • When significant perioperative blood loss is anticipated 1
   • InterStim is typically a minimally invasive procedure with minimal blood loss, so CBC is not routinely needed

2. Basic Metabolic Panel/Electrolytes

   • Only indicated for patients with:
     • Underlying chronic disease (hypertension, heart failure, diabetes)
     • Those taking medications that predispose to electrolyte abnormalities or renal failure 1

3. Coagulation Studies

   • Only indicated for patients with:
     • History of bleeding disorders
     • Medical conditions predisposing to bleeding
     • Those taking anticoagulants 1

4. Electrocardiogram (ECG)

   • Not indicated for asymptomatic patients undergoing low-risk procedures like InterStim 1
   • Consider only if patient has known coronary heart disease or other significant structural heart disease 1

5. Urinalysis

   • Recommended only for patients undergoing invasive urologic procedures or implantation of foreign material 1
   • Since InterStim involves implantation of a device, urinalysis may be considered

Special Considerations

Medication Management

• Assess need for perioperative management of anticoagulants if the patient is on them
• Review medications that might affect electrolyte balance

Infection Prevention

• Prophylactic antimicrobials are not routinely indicated unless the patient presents a high risk of infection 1

Common Pitfalls to Avoid

1. Ordering unnecessary tests

   • Routine preoperative testing in healthy patients undergoing low-risk procedures like InterStim does not improve outcomes and increases healthcare costs 2

2. Delaying surgery for normal variants

   • Minor laboratory abnormalities that don't affect perioperative management should not delay surgery

3. Missing important comorbidities

   • While avoiding unnecessary testing, don't overlook conditions that could affect surgical outcomes

Algorithm for Preoperative Testing for InterStim

1. For all patients: Review medical history and medications
2. If patient has cardiovascular disease: Consider ECG if known coronary heart disease or structural heart disease
3. If patient has renal disease or is on medications affecting electrolytes: Order basic metabolic panel
4. If patient has history of bleeding disorders or is on anticoagulants: Order coagulation studies
5. If patient has symptoms of anemia or conditions predisposing to anemia: Order CBC
6. For all patients: Consider urinalysis due to implantation of foreign material

InterStim therapy has shown excellent outcomes with low complication rates for treating urinary and fecal incontinence 3, 4, and proper preoperative assessment helps ensure optimal results while avoiding unnecessary testing.