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For Nerve Block Patients

 

 

Patients who are coming to Dr. Long for nerve blocks should review the information below to better understand the purposes of nerve blocks in diagnosis and treatment, as well as the following information about patient visits:

Currently block procedures are done in two locations.  There may be medical reasons for chosing one or the other.  Sometimes your insurance company makes the decision.  The patient care coordinator, Patti, will tell you where your procedure will be.

The current locations are:

American Radiology Services
Greenspring Station - Pavilion One
10755 Falls Road
Suite 130
Lutherville, MD  21093

             and

Timonium Surgery Center
1954 Greenspring Drive, Suite LL18
Timonium, MD  21093

Directions to American Radiology Services
American Radiology is in the Greenspring Center Complex, close to Dr. Long's Joppa Green office.

         Directions from 83 South going north:  

  • Take 83 North towards the Beltway.  83 North continues Right towards the Beltway but you must stay Left.  Do NOT exit onto Beltway East or West.
  • Stay Left and continue beneath the Beltway.  The two Left lanes of 83 North become Falls Road.
  • On Falls Road, at the first stop light turn RIght onto Joppa Road.
  • On Joppa Road, take the first Left onto Station Road.  This enters into Greenspring Station.
  • On Station Road take the 1st Left turn street and continue straight.  The last building on the Right is Pavilion I.
  • American Radiology is in Pavilion I, 1st floor on the left.

           Directions from 695:

  • Take 695, either direction, to exit 23B onto Falls Road. 
  • Follow the above directions from On Falls Road....

Directions to the Timonium Surgery Center

Directions from 695:

  • Take 695 to I-83 N toward Timonium/York, PA
  • Take exit 16 toward Timonium Road
  • Turn Right onto Greenspring Drive
  • Turn Right at Timonium Business Park, Timonium Two, 1954 Greenspring Drive, across from Tyre Auto.  The sign says Timonium Two Business Park
  • Follow the drive past several buildings and 1 stop sign.  Turn Left, just beyond the second large parking garage.  Go to the end of the office building on your right.  Turn right into the parking area.  Entrance to the Surgery Center is on the ground floor with parking near the door.  There are signs directing you to the Surgery Center.  Follow the signs.

Directions from I-83 North

  • Take I-83South towards Baltimore
  • Take exit 16 toward Timonium Road
  • Take ramp toward Timonium/Fairgrounds
  • Turn Left onto Timonium Road
  • Turn Right onto Greenspring Drive
  • Turn Right at Timonium Busness Park, Timonium Two, 1954 Greenspring Drive, across from Tyre Auto.  The sign says Timonium Two Business Park.
  • Follow the drive past several buildings and 1 stop sign.  Turn Left, just beyond the second large parking garage.  Go to the end of the office building on your right.  Turn right into the parking area.  Entrance to the Surgery Center is on the ground floor with parking near the door.  There are signs directing you to the Surgery Center.  Follow the signs.

Please review the Nerve Block Instructions before coming for your procedure.

Diagnostic and Therapeutic Nerve Blocks

Pain is the most common reason for spinal surgery.  Pain cannot be imaged.  Sometimes a combination of imaging studies and physical examination are adequate to determine a painful spinal problem to be corrected.  However, in many patients, complaints of pain are associated with multilevel degenerative changes and the attribution of pain to any specific level can be difficult.  Diagnostic blocks are physiological tests to help localize pain generators for treatment.

Diagnostic blocks involve anesthetizing a structure or its nerve supply to determine if doing so relieves the patient’s pain.  Blocks rely on the subjective response of the patient and controls are required to validate the blocks.

The diagnostic blocks are only required if a valid diagnosis cannot be established by other means.  Blocks may be either therapeutic or diagnostic.  Injection of steroids around an irritated nerve is an example of a therapeutic block.  The immediate benefits may be dramatic and the utility of the procedure is obvious.  Diagnostic blocks do not offer any direct therapeutic value for the patient.  Their purpose is only to localize a pain generator.  Simple diagnostic blocks may be useful to establish the limits of a proposed surgery or to make a specific diagnosis which allows a diagnostic process to stop and prevent ill conceived treatments.    

The structures most commonly subjected to blockade are facets, individual nerve roots, and intervertebral discs.  Less common procedures include intraosseous injections in the vertebral bodies, anesthetizing hardware, and blockade of apparent pseudarthrosis. 

The Validity of Diagnostic Blocks      

For these nerve blocks to be useful, they must do what they are supposed to do.  Validity is first established by use of fluoroscopic or CT control to guarantee the blocks are anatomically accurate and target specific.  Blind blocks have no validity.  Use of a contrast medium to assess spread of injected materials can add to the anatomical validity of the block when needed.

Validity must then be established by also determining the true positive and negative rates for a procedure.  

Sensitivity is the percentage of patients in whom the disease is present who are correctly detected as positive.  The specificity is the percentage of patients who do not have the disease and are identified to be without the condition.  By knowing the sensitivity, the physician can determine the value of a positive block and by knowing selectivity it is possible to know the appropriate interpretation of a negative block.  The false positive rate is most important because it may lead to an unwarranted treatment.  The false negative block may exclude a patent whom would benefit from an appropriate treatment and so is also important.

If these data are not known, no diagnostic test can be considered valid.  In order to know false positive and negative rates we should have controls for every diagnostic block done.  It is well known that single diagnostic blocks have a high false positive rate.  Control blocks may be of three types.  One may anesthetize some random nearby structure, placebo blocks may be utilized, or physiological controls can be done by performing identical blocks on different occasions using different agents of differing lengths of action.  We employ the first and last comparative local anesthetic blocks to improve validity in the diagnostic block protocol employed.  The objective of these control blocks is to minimize uncertainty in diagnosis to a practical level.  Comparative blocks can reduce the false positive rate to levels which are acceptable in clinical practice, so the results are helpful in choosing therapies.

There is another important practical point.  If the condition being tested has a very low prevalence, then single blocks of any kind are not likely to be positive.  This means that any protocol must employ blockade of the largest number of related structures practical.  A good example is the traditional three level bilateral facet block rather than performing individual joint blocks.  Whenever practical the maximum number of structures should be blocked with any procedure to reduce patient discomfort and cost, and should improve accuracy.

The protocol which we employ requires patients to be individualized according to the likelihood of the appropriate diagnosis.  For axial spinal pain typical blocks which might be used are those of the Axis-Atlas joint, cervical, thoracic, and lumbar zygapophyseal innervations, and sacroiliac joint blocks.  All techniques have been described and there is substantial literature concerning them.  With these blocks, two separate blockade sessions using anesthetic agents of different durations will provide adequate validity.  The data indicates two blocks are unlikely to be false positive and the operator can be 81% certain that a positive response to these blocks is a true positive.

A similar technique is used for nerve roots suspected to be involved in pain procedures.  Concordant blocks have a validity of around 90%.

Sacroiliac joint blocks are performed in the same way.  Between 87% and 91% of blocks will provide appropriate information to accurately diagnose a symptomatic joint.

These validity data mean comparative diagnostic blocks can be chosen based upon the likelihood of disease of the structures blocked to be involved in pain generation.  For a typical patient with low back pain who lacks specific clinical signs and symptoms, comparative blockade of facets, nerve roots which may be clinically involved, and lumbar discography should constitute an adequate screen.  Specifically chosen patients may require blockade of S1 joint, hardware, pseudarthrosis or other unusual structures such as a Tarlov cyst.  These patients are individually chosen, but the concept of comparative blockade remains true.  Validity has been established only for S1 joint blocks in this group, but 81-90% range is rational to assume for all.

The only blocks that are of proven therapeutic value are those in which the injections are made in periarticular areas or around nerve roots either transforaminal or epidural.  The injection of steroids in both situations has been demonstrated to provide lasting relief in some patients.  Positive blocks also predict success of radiofrequency denervation of diseased facets, if steroids fail.

Discography has been suggested to have predictive diagnostic utility and is commonly used to justify diskectomy and fusion, which may be either inter-body or posterior.  This is a logical inference.  Provocative discography is in common use and has been standard practice for many years.  Provocative discography validity is estimated to be 80-90%.

CPT codes exist for all these blocks, so all are recognized to be of value and all have been accepted by experts.

The goal of this protocol is to establish a way in which patients, who are incapacitated by pain but without definitive localizing findings for the pain generator, can be assessed in valid ways which will add to the information the clinician has in order to make therapeutic decisions.  Our plan is to provide the clinician with diagnostic blocks done in ways which provide both anatomical and procedural validity.  Accurate reports concerning the results of the block will be obtained by someone skilled in the use of interview techniques with chronic pain.  These results will then be supplied to the clinicians involved in the patient’s care for use in both diagnostic and therapeutic decision making.  These blocks are always used in context and never are reasons for surgery alone.

Block  Protocol Available

  1. Facet Innervation, Blocks, Diagnostic and Therapeutic:  Diagnose and treat pain of facet joint origin.
  2. Facet Denervation:  Treat pain of facet joint origin.
  3. Nerve Root Blocks, Diagnostic and Therapeutic:  Diagnose and treat Painful Root Compression, especially acute disc herniation.
  4. Discography:  Identify painful discs to aid surgical planning.
  5. Sacroiliac Joint Blocks, Diagnostic and Therapeutic:  Diagnose and treat S1 Joint Disease.
  6. Miscellaneous:  Hardware, Pseudarthrosis, Tarlov Cyst, Synovial Cyst, other structures.  Diagnostic:  Establish pain generator location.

Appointments may be scheduled by calling  410-828-7513.  Dr. Long will see patients prior to any requested procedure to be certain the patients understand the procedure and its purposes as well as risks and consequences.  The procedure will be completed and the report prepared for use by referring physicians.  The Nerve Block Instructions page provides information about how to prepare for your treatment and what to expect afterwards.