Burning Sensation after back surgery
Burning sensation after back surgery that may radiate to the back, thighs, and sometimes even radiate to distally located body parts such as feet or arms, is usually a result of either body’s normal healing process or agitated spinal nerves due to the surgery.
This burning sensation after back surgery is generally self-limited and resolves within weeks if not days without the need for intensive measures.
Causes of burning sensation after back surgery
What is a Failed Back Surgery Syndrome (FBSS)?
What factors hinder the recovery process after back surgery?
What are the methods for diagnosing burning sensation after back surgery?
What can be done to reduce the burning sensation?
What are the available treatments?
Causes of burning sensation after back surgery
Based on the onset, the burning sensation after back surgery can be acute if it started right after the surgery or chronic if it is persistent, progressive, and continues for 2 months or more.
Acute burning sensation following the surgery occurs right after the surgery.
It may be a phantom sensation felt due to the psychological stress associated with the surgery or it could indicate a normal healing process after the surgery.
Based on the type of surgery suggested for the patient, different reasons are found to be the cause of the acute burning sensation.
For example:
• scaring that indicates a normal healing process unlike other surgeries in the case of back surgery induces pressure on the adjacent nerve or nerve root which may present as a burning sensation. This form of burning sensation appears 6 to 12 weeks after the surgery as the scar begins to irritate the nerve.
The burning sensation caused due to scarring can be managed by using anti-inflammatory drugs or by simple exercises.
• Nerve irritation following the back surgery can also cause a significant burning sensation in the region of its innervation. Now, what causes the nerve irritation?
A number of factors can be the cause of such nerve irritation such as swelling if the nerve is accidentally damaged during the surgery or a remnant or debris in the vicinity of the nerve that might be putting pressure on the nerve thus causing discomfort.
The doctors suggest an early evaluation using radiologic imaging techniques to make sure there is no nerve damage due to the surgery that may need additional surgery.
• Facet joint syndrome is a common cause of spine related back pain. Facet joint is an anatomical connection between two adjacent vertebrae that provides stability to each vertebral section, thus promoting healthy movement of the spine.
This joint like any other joint in human body is protected by ligaments, capsule and synovial fluid and damage to any one of these can damage the integrity of this joint and result into facet joint syndrome.
This syndrome manifests as dull pain and limited range of motion in the affected region. It can be caused by aging or in this case trauma during surgery.
Since the degenerated facet joint becomes inflamed, it can compress the adjacent nerves and cause burning sensation in the region innervated by the nerve as well.
• The person sometimes suffers from burning sensation in the lower back much before the surgery is done. One of the most commonly overlooked diagnoses is the entrapment of the superior cluneal nerve which later persists after the surgery presenting itself as pain and burning sensation in the lower back and requiring further invasive surgeries.
The most important key factor is an accurate diagnosis before the surgery.
What is a Failed Back Surgery Syndrome (FBSS)?
The burning sensation after the back surgery in certain cases is persistent and stays much longer than the estimated time.
This chronic sensation can be a product of underlying complications which may result from multiple pre-operative, intra-operative, or postoperative factors.
This chronic, persistent and progressive burning sensation after back surgery that may stay for even more than 2 months is known as a failed back surgery syndrome.
Failed back surgery syndrome or FBSS mostly affects the lower limbs and back of the patient. Failed back does not mean that the back surgery was unsuccessful and thus this term can be misleading sometimes.
This syndrome actually represents the complications that arise after the back surgery. It manifests as chronic pain which may be in the form of burning sensation or a dull or sharp pain in the back, radiating to buttocks and legs.
There is no definite cause of failed back surgery syndrome and to this date, there is no significant evidence found for the provoked symptoms of this syndrome. Neuropathic pain or burning sensation (FBSS) persists regardless of the status of neural compression which means a change in position will not relieve the symptoms.
Persistent pain not only puts the burden on patients’ mental well-being but also puts pressure on the socio-economic aspects of life.
As the pain continues even after the surgery, the patient suffers from a functional disability which could be the reason for psychological problems in these patients such as depression and insomnia.
What factors hinder the recovery process after back surgery?
- Compensation received from the insurance companies:
Physicians and surgeons rely on the medical history taken from the patient to evaluate pain, abnormal sensations and the course of treatment; if a patient is receiving worker’s compensation or litigation he/she tends to prolong the treatment as shown in multiple studies to receive benefits from a work-place contrary to the people who are not getting any sort of compensation tend to recover more quickly than their counterparts.
A patient who smokes presents an additional challenge for surgeons; they require a longer healing period and also tend to have a lot more complications such as impaired wound healing, recurrence of infections, etc., than non-smoker patients.
Surgeons encourage patients to adopt a healthier lifestyle prior to undergoing invasive procedures to ensure the minimization of post-operative complications.
A patient is referred to a nutrition and physical medicine consultant so that these factors may help the patient during the recovery phase of the surgery.
Another key factor that derails a patient’s recovery and prolongs the course of treatment is depression. A number of studies have demonstrated that a patient suffering from depression more pronouncedly feels pain and requires more time to recover from the surgery.
Before the surgery, it is essential for the patient to go through these psychological evaluations to be sure that the patient is fit for the surgery and will benefit from it.
- Intra- and Post-operative factors:
Like pre-operative evaluation, a lot of factors arise during and after surgery that may cause neuropathic pain in the form of burning sensation.
Other than the normal body healing process some pathology may arise during or after surgery that may compromise the recovery.
One of the many is an inadequate technique used by the surgeon or failure to rule out the other associated factors such as after a surgery a nerve portion could be still compressed which leads to neuropathic pain after a phase of relief.
Post-operative complications will also affect the patient, as mentioned a long duration of hospital stay will increase the chances of the patient contracting any of the hospital-acquired infections at the site of surgery which may not only require further assistance but also enhance the complications.
- Another condition that results in neuropathic pain is:
A re-growth of bony protrusion after a laminectomy which is performed to decompress the nerve canal although it may not occur right after the surgery as understood that any sort of growth may require some time.
Any of these conditions make a patient prone to have failed back surgery syndrome or in other words, patients suffer from neuropathic pain in the form of burning sensations.
What are the methods for diagnosing burning sensation after back surgery?
Neuropathic pain in the form of burning sensations is often termed idiopathic in nature and is extremely difficult to diagnose as no definitive cause till now has been associated with it.
Although difficult to diagnose two surveys namely, Leeds Assessment of Neuropathic Symptoms and Signs (LANSS) pain scale and the Douleur Neuropathique en 4 questions (DN4) have been presented after multiple studies to show the efficacy of the surveys.
DN4 is usually given priority for the diagnosis but so far both surveys are not proven to be highly reliable in assessing neuropathic pain.
The absence of an appropriate tool for the diagnosis of the syndrome makes it difficult to treat. An absence of reliable diagnostic tools for the syndrome increases the need to use all sorts of diagnostic assessments to establish the diagnosis of neuropathic pain and also to rule out other causes.
A thorough post-operative diagnostic assessment is required to rule out other causes of pain and to establish a relation between surgery and neuropathic pain.
The first and foremost step is to establish the location and severity of pain that is hindering recovery. This not even helps in establishing an accurate diagnosis but also enables a physician to rule out other differential diagnoses that might go unnoticed.
For example, radicular pain that emerges right after the surgery may indicate misplacement of a screw that requires immediate surgery to relieve the patient of pain, if radicular pain is acute; it appears after 1 to 5 days of surgery indicate a hematoma or abscess or if the pre-surgical pain persists immediately after the surgery indicate that surgery has not been successful and may need additional procedures to relieve the patient, hence the need to evaluate the patient thoroughly to decide the appropriate course of treatment.
Imaging is an important tool in assessing the success of the surgery and determining the reason for pain and abnormal burning sensations. Plain X-rays have been widely used throughout history in assessing spinal deformities.
X-rays being the first tool for diagnosis has its limitation such as their inability to show the spine in three dimensions and not being able to display soft tissue etc., may become an obstacle in ruling out complex deformities such as nerve impingement.
Due to these limitations advanced imaging techniques are required.
Gadolinium-enhanced MRI is the gold standard for spine MRI but it also has its limitation in not being able to show the bony changes in the spinal cord which require computed tomography or CT scan assessment.
A nerve block or diagnostic nerve block is used both as a diagnostic and therapeutic tool. Despite nerve block is the epitome of inaccuracy it has been used historically as a mode of diagnosis.
In addition to a nerve block, steroids are administered to decrease nerve irritation until further evaluation is done. A nerve block can be achieved via two procedures either by blocking medial branches or by directly administering drugs into the joint.
What can be done to reduce the burning sensation?
As mentioned before, various factors play a role in causing burning sensation following a back surgery such as scarring, failed back surgery syndrome and facet syndrome etc.
Therefore, like other surgeries, back surgeries also require a thorough assessment of the patient’s physical and mental health to ensure the success of surgery; even more so as it requires more care during the recovery period.
The etiology of the pain varies from being phantom to infection or sometimes multiple factors are involved hence a thorough examination is required to determine the course of treatment. Certain studies have shown that a patient suffering from depression, anxiety, and emotional stress will have to deal with an increased chance of pain sensation than any other structural abnormality.
Any factor that may delay the recovery process will increase the duration of hospital stay which may result in infection and also increase the overall expense of the surgery.
As to avoid these complications patients are usually evaluated by a team to avoid post-operative complications.
Additional help before the surgery is needed by these patients such as pain education, psychological counselling, and physiotherapy to promote better coping.
What are the available treatments?
The goal of the treatment is to reduce the level of discomfort to an acceptable level in order to have a sufficient quality of life.
The management of neuropathic burning sensation has a wide range from non-invasive management with the help of physiotherapists and psychologists to invasive procedures like injections and nerve blocks and finally may need the assistance of surgical procedures.
After the diagnosis has been established, a careful consideration about the mode of therapy depending on the etiology of pain should be done by the attending physician to see what will bring the best outcome for the patient.
Pharmacological and non-pharmacological treatments have been used in neuropathic pain to alleviate symptoms.
Physical therapy and medications are the first lines of treatment for neuropathic discomfort or FBBS.
Psychotherapy has been also proven to show promising results including stress reduction and cognitive behavioral therapy.
Gabapentin has been the drug of choice for the treatment of neuropathic pain or discomfort in the form of burning sensations.
It is an anticonvulsant drug that in multiple randomized studies has shown promising effects in controlling burning sensation after surgical procedures. Another study has shown pretreatment with Gabapentin prior to the surgery reduces the chances of abnormal neuropathic sensations after the surgery.
Gabapentin has been actively used due to its proven safety profile and has shown more potent results than any other inflammatory drug such as naproxen in neuropathic pain. Oral Gabapentin with an epidural steroid injection has a synergistic effect which means simultaneous administration of both these drugs acts more effectively and has shown better results than steroid injects alone.
Anti-inflammatory drugs are given in low levels of discomfort but have little effect on severe neuropathic pain.
Other treatment options include anti-epileptics, non-steroidal anti-inflammatory drugs, anti-depressants, and opioids.
Chronic opioid therapy increases mortality and morbidity in a patient. If opioids are used for long-term pain management it may cause immune suppression, androgen deficiency, and depression.
In new therapeutic plans, physicians are more likely to avoid opioid usage in these patients.
Physiotherapy has been also recommended in such cases and also considered first-line treatment in patients who have a recurrence of burning sensation even after the surgery has been successful but little data is presently supporting the claim of physicians in alleviating pain via exercise.
Recent studies regarding this theory have stated that only isokinetic and dynamic lumbar stabilization has been proven effective in neuropathic pain and only one retrospective study has proven the use of chiropractors’ management after lumbar spine surgery.
Also note that some permanent restrictions after spinal fusion is needed just to be sure that spinal stability after the surgery is maintained, and these permanent restrictions can provide an optimal time for the spine to heal.
After medications, physiotherapy and psychotherapy are proven inadequate in the management of neuropathic pain, more intensive measures are required. Epidural steroid injections are used around the globe for pain management.
Epidural steroid injections not only work well with gabapentin but also reduce or prevent the chances of more invasive approaches.
The formation of fibrotic adhesions or scars is a normal healing process within the epidural space but presents a complication while administrating steroids injections as it blocks the targeted site of action.
The desired result could not be obtained unless a clear path has been created for the drug to reach its target.
Administration of hyaluronidase with hypertonic saline at the site of adhesion or into the epidural space lysis the adhesion and helps the drug to reach its target. It is effective to inject both hyaluronidase and steroid together as it has been proven more effective and has a long duration of effects.
Another procedure known as epiduroscopy, helps the physician to have visual confirmation of adhesions and direct lysis of it.
Spinal cord stimulation (SCS) has been recorded to be the most potent method used in the management of neuropathic pain.
Spinal cord stimulation or SCS of today is more refined and effective in achieving the set target of reducing the effects of spinal surgeries.
SCS-induced analgesics not only have direct effects on the spinal cord but also influence the supra-spinal region of the central nervous system by inducing descending inhibitory pathways and inhibiting pain facilitation.
Numerous trials have proven the supremacy of SCS’s effectiveness over that of revised surgical procedures.
Although being an invasive procedure SCS tends to be more effective and safe than any other invasive procedure and has shown tremendous success in these patients. It not only provides long-term relief but also improves the patient's quality of life and would be more cost-effective than other procedures.
Surgical revisions are considered the last resort if all other techniques fail although it remains an unlikely scenario.
As mentioned before and proven by various studies, revised surgeries are more likely to increase pain and could result in long-term morbidity.
Revised surgeries are only recommended in some cases where surgically correctable cases are present such as residual stenosis, instability, or disk degeneration.
Neuropathic burning sensation after back surgery or Failed back surgery syndrome is considered an unavoidable challenge for physicians and surgeons.
Even after a thorough examination and different modes of evaluation prior to the surgery FBBS/neuropathic pain or burning sensation presents itself as a postoperative complication in most back surgery patients.
Due to being mostly idiopathic in nature and the absence of adequate diagnostic tools multidisciplinary treatment is required to tackle the complex etiology of the disease. SCS dominates the treatment approach in such cases and has shown promising results in the long-term management of the syndrome.
Epidural lysis with steroid administration is an effective treatment modality but only provides short-term management and pain may recur after a period of relief.