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TREATMENT OF ENTRAPMENT
NEUROPATHY IN THE FOOT
Stanford Rosen, DPM
Abstract. Entrapment neuropathy is an inflammatory injury in a localized region in a peripheral nerve that is caused by mechanical irritation from some impinging anatomical neighbor. It may occur at the point at which a nerve goes through a fibrous or Osseo fibrous tunnel or where the nerve changes its course over a fibrous or muscular band. Although external force may have been applied directly to the region, in many causes there is no discernable relationship of the condition to trauma.
Once trauma, either exogenous or endogenous, has occurred at the entrapment point, the anatomical configuration causes repetition of mechanical irritation provoking and maintaining an inflammatory response and pain. The injury can occur directly to the nerve substance or to the intrinsic blood supply of the nerve trunk. This can cause degenerative tissue change and replacement fibrosis.
Peripheral nerves must be able to move with relation to neighboring structures. A nerve tank does not have as much inherent elasticity as a blood vessel which can stretch more easily to make up the extra distance called for by body movement. An entrapment point does not seem impressive at the anatomy table, but this could be a region of significant pressure and interference with the passive motion of the nerve. Determining the stress anatomy of the region is a major concern for clinicians and helps to differentiate a number of painful conditions in the foot.
The report chronicles a series of cases categorized by treatments. No controls were employed and several variables preclude the ability to draw definitive conclusions. However, according to patient reports, it appeared that the combination of lidocaine 1%, Sarapin®, B-12, dexamethasone, and anti-inflammatory medicines provided a significantly longer duration of pain relief in neuritis and muscular pain than the other combinations employed.
Descriptors. foot pain, entrapment, peripheral nerves, Sarapin®
AJPM 2004; 14:71-74 Received: 04-25-03; Accepted: 10-08-03
INTRODUCTION
Seventy-five patient cases emanating from a private podiatry office are reported. The primary investigator treated a total of 90 patients presenting with foot pain and neuritis symptoms in a three-month period. Fifteen patients chose not to participate. Following the initial diagnosis, which included a history and physical examination with radiology views, all of the remaining 75 patients required treatments and agreed to the treatment plan after the nature of the plan was described.
Diagnoses treated. The diagnoses of the 75 patients included (i) plantar fasciitis with neuritis and involvement of the calcaneal branch of tibial nerve and or sural nerve, (ii) metatarsalgia with involvement of the interdigital plantar nerve, Morton‚s neuroma, and (iii) tarsal tunnel syndrome with involvement of the posterior tibial nerve. All of the patients with any of these diagnoses were also diagnosed with a corresponding biomechanical cause factor that would also be treated with proper orthotics. In the opinion of the treating clinician, all of these conditions were associated with mid-foot pronation problems.
Patients. Demographic features of age, weight, gender, work status, onset to neuritis, and other historical features were recorded I the chart but not
considered in the inclusion or exclusion criteria. The sole criterion for inclusion, in addition to one or more of the diagnoses cited, was neuritis "neuritis characterized by the symptoms of burning, numbness, tingling, and pain. All of the patients included presented with these four symptoms. Thepatients were randomly and evenly assigned to one of three groups (25 patients per group).
METHODOLOGY
Group 1. One-third of the patients were assigned to Group 1. These patients received somatic nerve blocks to offending nerves with 3 cc of a combination of 1 cc lidocaine 1%, 1 cc Sarapin®, 0.5 cc vitamin B-12, and
0.5 cc dexamethasone phosphate.
Group 2. One-third of the patients were assigned to Group 2. These patients received somatic nerve blocks to offending nerves with 3 cc of a combination of 1.5 cc lidocaine 1%, 1 cc Sarapin®, and 0.5 cc vitamin B-12.
No dexamethasone was used.
Group 3. One-third of the patients were assigned to Group 3. These patients received somatic nerve blocks to offending nerves with 3 cc of a combination of 1.5 cc lidocaine 1%, 1 cc of bupivocaine 0.5%, and 0.5 cc
vitamin B-12. No Sarapin® or dexamethasone was used.
TREATMENT
First visit. The first office visit was devoted to an orientation to the plan and explaining the problem and what was expected of each patient. It would be necessary for the patient to be seen on a weekly schedule for four weeks, then ever-other-week for four weeks. We would then see them every our weeks for two visits. The entire study would require a total of eight
visits. They would receive a somatic nerve block(s) either unilateral or bi-lateral depending on their symptoms. The nature of the block was determined by
group assignment. The locations of the block(s) was determined by the nature of the specific diagnosis and the affected nerve.
The patients were given prescriptions for anti -inflammatory medications such as Celebrex® 200 mg daily, orally or Bextra® 10 mg daily orally, secondary to an evaluation of each patient‚s history in taking these types of medications. During this visit, the second appointment was made.
Second visit. When the patients presented for their second visit, each was examined and questioned as to treatment experience secondary to the first visit. Each patient was fitted and given full instructions on the use of the Biostim® neuromuscular stimulator. A second somatic nerve block was administered in accordance with the original diagnosis. The patients were instructed to start stretching exercises for their affected muscles and joints. A third visit appointment was made one week hence.
Third visit. During the third visit, each patient‚s progress was evaluated and recorded. Additionally, the patient‚s experience with the use of the Biostim® unit was evaluated. A cast for custom orthotics was made according to biomechanical problems in original evaluation. Each of the three diagnosis need a different type of orthotics. Also, it was necessary to determine what style shoes were to be worn to help determine the orthotic device that best met the patient‚s needs. Two pairs of orthotics were made ˆ one for dress and one of sport shoes. Third somatic nerve block(s) were administered according to original diagnosis. Finally, a fourth visit was scheduled one week hence.
Fourth visit. The fourth visit entailed an examination and recording of progress. Each patient was evaluated on the use of the Biostim® unit and the findings recorded. Fourth somatic nerve block(s) were administered according to original diagnosis, if needed, and the fifth visit appointment was made.
Fifth visit. The fifth visit also entailed an examination and recording of progress, as well as an evaluation of the experience with the Biostim® unit. The custom made orthotics to control biomechanical problems were fitted to the patients‚ shoes and feet. Gait analysis was undertaken and the results recorded. The fifth somatic nerve block(s) were administered according to original diagnosis, if needed, and the sixth appointment was made.
Sixth and seventh visits. During the sixth and seventh visits, each patient's progress was recorded secondary to an examination. Additionally, the progress made secondary to the use of the Biostim® unit and orthotic devices was evaluated and recorded.
Eighth visit. At the eighth visit, a complete examination and recording of progress as well as overall success or failure of treatment plan was undertaken. Each patient was reappointed in six months for follow-up
evaluation.
RESULTS
During the eighth visit, data collection revealed an overall improvement in the original subjective symptoms in 86% of the patients. Five patients were
operated on for tarsal tunnel release, three underwent operations for neuroma removal, and two had plantar fasciae releases. Patients in each group were evaluated for various complications including infection, rash, and reaction. No complications were noted in any of the patients in any one of the three groups.
DISCUSSION
The duration of pain relief secondary to each block was significantly longer in Group 1 than Group 3. After the second block, it was noted that the pain relief duration within Group 1 was superior to Group 2 and 3, and the
duration of relief seen in Group 2 was superior to that in Group 3. In addition, no changes were noted between the fi5rst and subsequent blocks in
Group 3, but significant improvements secondary to the second through the fourth blocks in the other two groups were noted. Blocks were not needed in
Groups 1 and 2 after the fourth block, but were still utilized through the fifth visit for Group 3. It was concluded that the use of a combination of lidocaine 1%, Sarapin®, vitamin B-12, and dexamethasone (Group 1) appeared to provide a significantly longer duration of pain relief in neuritis and muscular pain than that seen with the other combinations.
Sarapin® is a suspension of powdered Sarracenia purpurea (pitcher plant) inalkaline solution. Although commonly used in some quarters, it is unknown
to many. The value of Sarapin® in relieving pain of neurological origin was first reported by Judovich and Bates in 1931. Subsequent clinical reports on
Sarapin® are few and are lacking. Sarapin® has been reported to cause no motor weakness following injection of the peripheral nerve, no loss of touch, pressure, or pinprick, and no temperature sensibility
(1). Other papers have attested to its use in migraine (1), sciatica (2), low back pain (3), and diabetic neuropathy. Lidocaine provides immediate local anesthesia of the neurological focus of pain onset; corticosteroids (e.g., dexamethasone) relieve any local inflammation involved with the neurological stimulation; vitamin B-12 not only helps with the neuritis but enhances the other components; and Sarapin®
appears to offer a prolonged anesthetic effect on C-fiber-transmitted pain impulses (1). Thus, the pain presented is quickly absorbed and controlled
immediately after injection. The use of the neuromuscular stimulator (Biostim®) (i) assists the patient with re-education of muscles involved;
(ii) improves range of motion; (iii) prevents/retards disuse atrophy; (iv) promotes healing/reduces edema; (v) increases circulation; and (vi) decreases inflammation.
CONCLUSIONS
The results of this study show significant improvement in foot pain control secondary to the use of controlled blocks with the addition of adjuvant agents. The combination treatment protocol of neuromuscular stimulator reducing the inflamed nerves, muscles, ligaments an joints, the therapeutic blocks with Sarapin® and dexamethasone, and proper biomechanical control of imbalances that caused the entrapments gave superior end results to 86% of
the patients treated.
REFERENCES
1. McCalla CX. Instantaneous cure of acute frontal cephalalgia (unpublished
article), 1995. Web-address: http://www.sarapin.com/migraine.html
2. Namey TC. Differential diagnosis and treatment of sciatica: the non-diskogenic causes. Advanced Clinical Updates 1985; 1(5).
3. Manchikanti L. et al. Effectiveness of lumbar facet nerve blocks in chronic low back pain: a randomized clinical trial. Pain Physician 2001;
4(1): 101-117.
4. Rask M. The omohyoideus myofascial pain syndrome. Jour Cranio Pract 1984; 2(3).
5. Injection technique in pain control. Serapin® reference manual.
Levittown, PA: High Chemical Company.
Dr. Stanford Rosen is board certified by the American Academy of Pain Management, American Board of Podiatric Surgery, Ambulatory Division, and
the American Medical and Surgical Specialties Board in Primary Foot Care and Surgery. He is also a Certified wound Care Specialist (CWS). Dr. Rosen is
a Fellow and founding member of the Academy of Ambulatory Foot Surgery and served as their Executive Director for 10 years. Dr Rosen is a member of
the American Association of Orthopedic Medicine and is a Senior Disability Analyst and Diplomat of the American Board of Disability Analysts. Dr Rosen
is currently serving as Medical Director for Advanced Foot Health Centers as well as Medical Solutions, LLC in Alabama. Reprints: www.AJPMOnline.com
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