Insertion of intrathecal catheter and pump can cause complication because of surgery and opioid medications.
Intrathecal Pain Pump Post-Surgical Complications Includes The Following-
- Bleeding may occur within 1 to 3 days in catheter or pump pocket following abdominal straining or coughing.
- Pump pocket hematoma may not be diagnosed earlier as pocket can retain substantial amount of blood.
- If bleeding is substantial or marginal but continuous after 72 hours then surgical exposure of pump and/or catheter pocket is necessary to control bleeding.
- Nerve injury may occur while placing needle or catheter in intrathecal space.
- Laceration of cauda equina results in isolated single or multiple nerve damage.
- Symptoms of nerve injury are pain, sensory loss, and/or muscle weakness. Sensory or motor deficits are observed in the dermatomal distribution of the damaged nerve root.
Spinal Cord Injury-
- Damage to the spinal cord would lead to dysesthesia or myelopathies below the level of the damaged spinal cord.
- Spinal cord injury while placing needle or catheter may result in cauda equina syndrome.
- Cauda equina syndrome is presented with symptoms of severe pain, sensory loss, weakness, and bowel/bladder dysfunction.
- The sensory and motor deficits would be detected in multiple dermatomes in a saddle distribution.
- Seldom inflammation of injured spinal cord results in transverse myelitis followed by progressive necrotic myelopathy leading to paraplegia.
Shredded or Fractured Catheter-
- Catheter is inserted through needle into intrathecal space.
- If spinal canal is narrowed or scarred because of stenosis, arachnoiditis, or other intraspinal abnormalities catheter may not thread through needle.
- Multiple trial of threading may shred catheter or fracture (tear) the catheter. Infrequently torn proximal piece of catheter may float in CSF and never cause any symptoms.
- Shredded and fractured catheter can be pulled out of back with needle and catheter withholding in CSF is prevented.
Infection and Meningitis
- Postsurgical infection causes formation of pus in catheter and pump pocket.
- Infection and pus travels along the catheter into cerebrospinal fluid and may result in meningitis and encephalitis.
- Patient may develop epidural abscess.
- The symptoms and signs of meningitis are as follows-
- Nuchal rigidity
- Changes in level of consciousness
- Leukocytosis- increased white blood cell count
- Elevated erythrocyte sedimentation rate
Complications Associated With Intrathecal Catheter
- Catheter Retraction- Catheter can retract into epidural space or pump pocket.
- Catheter Dislocation- Catheter may dislocate from connection at pump. If catheter dislocates, there may be CSF leakage in the pump pocket causing seroma.
- There may be mechanical, electrical or electronic failure of pump though it is extremely rare.
- Pump may be replaced.
Morphinoma- Morphine Granules Forming A Solid Ball At The Tip Of The Catheter
- Morphinoma is a granuloma mass at the tip of the spinal catheter.
- Granuloma is an expanding sterile mass observed after several weeks of intrathecal morphine infusion.
- Granuloma is suspected if patient is complaining of severe new radicular pain that worsens despite escalating doses of intrathecal opioids.
- Pain is often associated with new neurologic symptoms such as numbness, weakness or bladder insufficiency.
- All opioids such as morphine, hydromorphone, methadone and naloxone cause formation of granuloma. Fentanyl when used intrathecally does not cause granuloma.
- An MRI or high resolution CAT scan myelogram should be obtained to confirm the mass around the tip of the catheter. Space occupying lesion by morphinoma may result in permanent nerve damage if not treated.
- Granuloma has never been reported in any patients receiving Baclofen. Granuloma is caused by morphine or hydromorphone precipitation and not by catheter induced inflammatory reaction of CSF. Morphinoma appears after several months of opioid infusion through catheter in the intrathecal space.
- Precipitation depends on flow rate, pH of opioid solution, concentration of opioids and difference in osmotic pressure between opioid solution and CSF.
- There is also a suggestion that clonidine used in combination with opioids may decrease the incidence of this complication.
CSF Leak Around Catheter
- Catheter is passed through spinal needle, which is larger in diameter than catheter.
- One in four patient has CSF leak around catheter, which stops once surrounding tissue seals around catheter.
- CSF leak may last from one to several weeks if not sealed or treated.
- Persistent CSF leaks causes post-dural puncture headache and following symptoms-
- Ringing in the ears
- Persistent CSF leak is treated with Intravenous fluids, oral or intravenous caffeine, bed rest and epidural blood patch.
- Epidural blood patch is performed under aseptic technique in surgical center by injecting up to 10 cc of autologous blood in the epidural space.
Hygroma Or Pump Pocket Seroma
- Catheter dislodged from pump or tear can cause severe CSF leak in pump pocket. Hygroma is an accumulation of CSF in pump pocket.
- Do not aspirate pump pocket, needle insertion may introduce infection.
- Continuous leak after 2 weeks may need revision of catheter or reconnection of catheter to pump.
- Seroma is a sterile fluid secreted by soft tissue, which surrounds catheter and pump. Serous secretion is reaction to foreign body such as catheter and pump placed in subcutaneous pocket. Serous fluid gradually accumulates in pump pocket.
- Pressure bandage and observation for two weeks is essential, leak stops in 2 weeks.
- Serous fluid secretion last for 1-2 months and is self-limiting. Abdominal binder may be beneficial to decrease the size and discomfort of the seroma.
- Side Port Myelogram Test- Side port myelogram is a dye study performed to diagnose a catheter disconnects or leak. Needle is inserted in to side port of the pump under aseptic provision. Dye is injected through side port. Dye passes from side port to catheter through connecting compartment of pump. If catheter is disconnected dye passes into pump pocket, similarly if catheter is torn within pocket then dye will be seen under x-ray in pump pocket. Hygroma can be differentiated from seroma following dye study.
- Symptoms such as fever and increased white blood cell count suggest infected pump pocket. If serous fluid collected in pump or catheter pocket is infected then the fluid should be aspirated from pump pocket for lab study.
- Aspirated fluid must be examined for bacteria and antibiotic sensitivity test.
- Infected pump pocket should be explored to remove catheter and pump as soon as possible to prevent meningitis or encephalitis.
- Superficial Infections – Blood examination and bacterial culture of purulent secretion will determine seriousness of infection. Mild infection is treated with appropriate antibiotics. Explantation is not necessary for superficial infection.
- Serious infections may cause abscess formation in catheter or pump pocket. Frank purulent discharges may be observed.
- Catheter and pump are explanted followed by appropriate antibiotic therapy.
- Failure to remove the pump and catheter may result in continuous infection. Life threatening meningitis and encephalitis may result if not treated appropriately with antibiotics.
- Infections involving epidural or intrathecal space require immediate removal of all implanted devices and followed by intravenous antibiotics.
- May result in epidural abscess.
- Epidural abscess may cause space-occupying lesion such as compression of spinal cord.
- If an abscess is suspected, an MRI or CT should be obtained urgently. If positive, all implanted hardware should be removed.
Prevention of Infection-
- Surgery is performed under strict sterile techniques.
- Prophylactic antibiotics are prescribed during and after surgery. Oral antibiotics are prescribed during postoperative period for 7 to 10 days.
- Pump and catheter pocket is washed with antibiotic solution during surgery.
- Surgical incision and wound is monitored for first 2 to 4 week. Wound care and further investigation is considered if following signs are observed-