Lumbar Intervertebral Disc Herniation
Low back pain is a universal phenomenon. The economic cost in the United States, in terms of lost time and medical expense, amounts to 1.9 billion dollars annually. Over 200,000 patients have surgery for ruptured lumbar discs yearly in the United States.
While laminectomy for disc removal is the standard, it is not without its’ well-known morbidity. Because of this, disc surgery has progressively evolved in the direction of decreasing surgical invasiveness to the patient. Microtechniques are now an alternative to traditional discectomy. Percutaneous discectomy was introduced in 1975, by Hijikata et al, and now the concept of approach through the skin for surgical treatment of a herniated lumbar disc is quite appealing. The indications and applications are broadening with new technology. As with any patient with a herniated disc, the conservative approach should be the first line of treatment. It is important to note that conservative approaches will differ from physician to physician.
In many studies, conservative intervention includes bed rest, muscle relaxants, non-steroidal anti-inflammatory agents, and epidural injections. It often excludes any form of physical therapy. This raises two issues. First, healthcare professionals need to be cognizant of the latest advances in surgical techniques for patient education, appropriate rehabilitation, and proper communication among medical personnel. Second, why is physical therapy often excluded as a means of conservative treatment? This report presents a brief description of recent surgical techniques, overviews of success rates, treatment goals, and a discussion of the utilization of physical therapy.
Review of Literature
Lumbar disc pathology causing nerve root compression seldom occurs from a single traumatic event, but results from progressive degeneration with episodes of intensifying symptoms. There are four classifications of disc pathology which often vary in the applicable literature.
First, a protrusion may occur where the disc bulges without rupturing the annulus fibrosis. Second, a disc may prolapse where the nucleus pulposus migrates to the outermost fibers of the annulus fibrosis. Third, there may be a disc extrusion. In this case the annulus fibrosis is perforated and material of the nucleus moves into the epidural space. Lastly, a sequestrated disc may occur as fragments from the annulus fibrosis and nucleus pulposus are outside the disc proper.
The initial stage in the evaluation of potential disc disease is a meticulous history and physical examination. Numerous special tests are used to reproduce and/or irritate a possible nerve root compression pathology. However, we are somewhat limited in clinical testing and the findings are used in conjunction with other forms of examination. The raised straight leg tests and compression tests are indicative of neurological involvement. The neurological examination assists in revealing a suspected level of pathology and the presence of sensory or motor deficits.
Several radiographic tests are helpful in determining the diagnosis of lumbar disc herniation and locating the source of pain. They help the surgeon indicate the extent of surgery needed to fully decompress the nerve. X-rays show structural changes of the lumbar spine. Myelography is a special x-ray of the lumbar spine in which a dye or air is injected into the patient’s spinal canal. The patient then lies strapped to a table as the table tilts in various directions and spot x-rays are taken. X-rays showing a narrowed dye column in the intervertebral disk area confirm possible disc herniation.
CT scans exhibit the details of pathology necessary to obtain consistently good surgical results. MRI analysis of the lumbar discs can accurately depict the early stages of nuclear aging and degeneration.6 EMG’S (electromyograms) measure the electrical activity of the patient’s muscle contractions and possibly show evidence of nerve damage. This testing is a powerful tool for assessing muscle fatigue associated with muscle impairment with low back pain.
There are several approaches taken to mediate lumbar disc herniation. The nomenclature is usually the classic discectomy, microdiscectomy, or percutaneous discectomy. The basic differences among these procedures are the size of the incision, how the disc is reached surgically, and how much of the disc is removed.8
Chemonucleolysis is an alternative to surgical excision. Chymopapain, a purified enzyme derived from the papaya plant, is injected percutaneously into the disc space to reduce the size of herniated lumbar discs. It hydrolyses proteins, thereby decreasing water-binding capacity when injected into the nucleus pulposus inner disc material. The resultant reduction in size of the disc relieves pressure on the nerve root. The injected disc tends to redevelop itself with normal tissue composition within the confines of the intervertebral space.
Despite the advantages, this procedure only enjoyed a brief popularity. This was the result of a small incidence of anaphylactic reactions including death, reports of subarachnoid hemorrhage when the enzyme became mixed with radiocontrast material, and unexplained paraplegia.
More recently, however, studies have shown that shortly after the introduction of chemonucleolysis, 7,000 neurological and orthopedic surgeons in the U.S. received one day of training in the performance of chemonucleolysis. In retrospect this training was inadequate, which may have led to the unsatisfactory and catastrophic neurological outcomes which occurred in some cases. In contrast, the procedure is being successfully performed with increasing frequency elsewhere, especially in Europe, primarily due to the fact that only experienced surgeons with extensive training perform the procedure. If the problem is corrected by a discectomy, the intent is the surgical removal of the portion of the disc that is putting pressure on a nerve causing the back pain. In the classic discectomy, the surgeon first makes an incision in the midline of the back. Then, to visualize and reach the herniated disc, the surgeon removes some or all of the lamina, hence the term laminectomy. The surgeon removes the disc material that is pressing on a nerve. It is important to note that despite the terms discectomy and laminectomy, rarely are the entire lamina or disc removed. Often only one side is removed and is termed hemi- laminectomy.
Closely related to the classic laminectomy/discectomy is the microdiscectomy. Through the use of an operating microscope, the surgeon removes the offending bone or disc tissue until the nerve is free from compression or stretch. After the nerve roots have been exposed and identified, the magnification is turned up and the nerve roots are probed in an attempt to reproduce the back and leg pains that closely resemble the patients pre-operative complaints. This is possible from the use of local anesthesia, which is one advantage of less invasive procedures. The offending nerve may be anesthetized, allowing adequate pain relief to retract the nerve root gently and provide sufficient exposure to visualize the disc. At this point the surgeon is able to thoroughly explore and determine if there is a need to remove additional bone, ligament, or disc. Although there are varied techniques in microsurgery, they all share theoretical advantages over the standard discectomy such as: smaller incision, less trauma to lumbar musculature, easier identification of deep seated structures, less traumatic manipulation of neural structures, and direct view into the disc space through microscope magnification. Whether these advantages translate into superior final outcomes is still controversial.
It is important to note the surgeon seldom opts for a radical disc removal, but instead chooses to remove only loose and degenerated portions of the disc. One surgeon states that overly-ambitious attempts to remove a great deal of disc tissue increases the likelihood of nerve injury due to the increased surgical trauma.
Lumbar fusion is the process where removed disc material is replaced by bone grafts that are harvested (usually from the iliac crest) and placed between the intervertebral bodies in place of the disc. This approach is used when there is a need to return the normal anatomic relationship between the motion segment in patients whose stabilizing segments and neural structures are unstable. A total discectomy needed for lumbar fusion prevents recurrent lumbar disc herniation at that level. A wide laminectomy in lumbar fusion relieves all neural compression from structures other than the disc, especially in cases of lateral spinal stenosis. Fusion can take place at different angles, such as anterior, anterior lateral, or posterior lateral, depending upon where the patient will benefit the most.
One of the most common is the posterior lumbar interbody fusion. In one particular technique the patient is prone and the incision is horizontal with grafts removed from the iliac crest through this same incision. A bilateral laminotomy exposure is made keeping ligamentous and facet structures intact whenever possible. In this procedure the controlling of epidural hemorrhage becomes a factor in success rates. Disc space is entered by cutting a large square plug to reveal the bone edges of adjoining vertebral bodies. Disc material is then removed and usually comes out in large chunks. Generally at least 75% of the posterior disc material is removed usually 25-30 mm in depth. A split thickness graft is then removed from posterior iliac bone. The block shaped graft is then cut into 4-6 peg grafts the size of which is dependent on the height. After all the grafts are inserted, care is taken so that no undue pressure from the grafts are on the nerve root. Generally solid fusion occurs about four months after surgery.
Percutaneous disc excision is beginning to have increasing popularity with it’s multiple advantages. It is performed on an outpatient basis, which is less expensive, and does not require general anesthesia. The purpose of percutaneous disc excision is to reduce the volume of the affected disc indirectly by partial removal of the nucleus pulposus, leaving all the structures important to stability practically unaffected. In percutaneous discectomy, open operation is avoided by inserting a 5 mm cannula with a device called a nucleotome, which consists of a trochar with a side window, a cutting device, and suction capability. The trochar is introduced under radiologic guidance into the disc. Suction is applied and the disc protruding into the window is sliced and aspirated.10 As an alternative to both chemonucleolysis and the classic laminectomy, percutaneous techniques are steadily gaining ground.
Arthroscopic microdiscectomy is similar to percutaneous discectomy but incorporates modified arthoscopic instruments including scopes, automated suction punches, automated cutters, and a series of curets. The instruments are used through a 6.5 mm sleeve. A bilateral technique is often used to allow visualization during discectomy. Two access cannulas are introduced posterolaterally from the right and left side of the patient. A suction irrigation of a saline solution is established through the two ports. A video discoscope is introduced from one port and the deflecting instruments from the opposite side. In this way the surgeon is able to search and extract the nuclear fragments under direct visualization.
Laser disc decompression is performed from the same approach as percutaneous excision and arthroscopic microdiscectomy procedures, but laser energy is used to remove the disc tissue. Here laser energy is percutaneously introduced through a needle to vaporize a small volume of nucleus pulposus, thereby dropping the pressure of the disc and decompressing the involved neural structures. The point of entry is posterior-lateral, usually 8-10 cm from the midline and above the iliac crest. A 20-cm, 18 gauge needle is inserted under biplane flouroscopic monitoring into the disc, between the two endplates, until the tip is approximately 1 cm posterior to the center. Once in the proper place, laser energy is transmitted to the disc by inserting a laser fiber inside the needle.
Some advantages over conventional laminectomy/discectomy and microsurgical procedures are its’ relatively noninvasiveness and that it takes place in an outpatient setting, using local anesthesia with a short treatment time of approximately 30 minutes. One disadvantage is the initial high cost of laser equipment. Indications for laser surgery are similar to other less invasive procedures, including no previous surgery and absence of complicating factors such as spinal stenosis, spondylolisthesis, etc.
Percutaneous laser discectomy, as well as the other percutaneous procedures, are alternatives for the patient who cannot tolerate general anesthesia or extensive surgery due to secondary health problems such as heart conditions.
Study of Surgical Success Rates
Percutaneous Laser Discectomy: A Patient Panel Study
A report by Choy et al, describes a study of 333 patients treated with PLDD (percutaneous laser disc decompression). The longest follow-up was 62 months (with a mean of 26 months) for 141 women and 192 men with patient ages ranging from 23-81. It reported on a total of 377 discs, of which 226 were L4-5, 119 were L5-S1, 30 were L3-4 and two were L2-3. Eleven patients had repeat laser surgery varying from 1-4 times and between 3-9 months. Thirty-two patients had the L4-5 and L5-S1 discs treated at one sitting.
Criteria for patient selection were:
1. MRI or CAT scan documentation of contained nonsequestered intervertebral disc herniation;
2. clinical symptoms of radicular pain;
3. failure of response to conservative therapy after three months which consisted of bed rest, local heat, muscle relaxants, nonsteroidal anti-inflammatory agents and undefined physical therapy;
4. no stenosis, facet impingement, or spondylosis;
5. examination by a neurologist;
6. no economic gain from continued disability;
7. no previous surgery;
8. no hemorrhagic diathesis;
9. cardiac clearance; and,
10. signing by the patient and a witness of an informed consent form.
The patients were examined on post-op day one, at one week, one month, three months, six months, and every six months after the procedure. After six months the MRI was repeated whenever possible. The procedures for the L-2, L3-4 and L4-5 discs generally took 15-30 minutes; the L5-S1 discs took 30-45 minutes. The MacNab criteria of response to treatment was used, which is a classification system of ‘good’, ‘fair’, and ‘poor’ answered subjectively by the patient in addition to objective findings from the clinician.
‘Good’ was defined as resumed preoperative function with no medication dependency and no appropriate signs of nerve root impairment, with some occasional backache or leg pain.
‘Fair’ was described as intermittent episodes of mild lumbar radicular pain and/or low back pain, no dependency-inducing medications, activity appropriate and no objective signs of nerve root impairment.
‘Poor’ was described as no productivity, continued pain behavior, medication abuse, inactive, compensation and/or litigation focus and objective sign of continuing radiculopathy.
Rated good to fair were 261 patients (78.4%). Of this group, 166 experienced relief of pain during the procedure persisting to the present. Twenty-one experienced gradual continuing relief of pain beginning approximately three to four days after the procedure, attaining total loss of pain four weeks post-op. Seventy-four patients reported partial recurrence of radicular pain on the first post laser day with gradual improvement occurring over the next two to three weeks. Most of the responding patients returned to work in four days. There were 72 failures (21.6%). These patients all had subsequent operative intervention.
Approximately one-third repeat MRI’s 4-6 months post-op showed slight to moderate decrease in disc herniation. One complication was discitis, seen after both PLDD and open surgery. It was necessary to repeat PLDD in 11 patients with benefit to seven (64%). Seventy-two patients who did not respond to PLDD received subsequent open discectomy with pain relief, showing PLDD does not preclude future surgery. The authors stated possible cause for failures may have been a less desirable quality of MRI and CAT scan studies stating that some less than ideal discs were included in the study. At least five patients turned out to be Worker’s Compensation cases who fell through the screening procedures early on in the study and six patients did not receive adequate laser energy.
The authors of this study concluded that PLDD is a safe, relatively noninvasive and effective treatment modality for contained, non-sequestered, herniated lumbar intervertebral discs disease, provided patients are carefully selected.
Microsurgical Discectomy Compared with Classic Discectomy/Laminectomy
In a study conducted by Caspar, M.D. et al, the outcome of 119 patients who were operated on by conventional standard discectomy were compared to 299 patients who were operated on with a microsurgical discectomy (MSD) technique. All patients in this series had virgin lumbar radiculopathy evaluated and operated upon by two experienced surgeons at one institution. Determination of the final outcome was made objectively by an impartial third party using identical criteria for both groups and with a patient self-evaluation form. Preoperative evaluation included history, physical examination, and films of the lumbar spine. Diagnostic studies included myelography in 78% of the standard discectomy and in 99% of the microsurgical discectomy. All patients had persistent and severe sciatica with positive physical findings, such as positive straight leg test, muscle weakness, decrease in deep tendon reflexes, and sensory changes unresponsive to conservative treatment including undefined physical therapy.
The patient’s clinical history, preoperative physical examination, intraoperative findings, postoperative course, condition at discharge, and follow-up examinations were assessed using hospital records and self-evaluation questionnaires. The mean duration of follow-up examination was 6.4 years for the standard discectomy group and 2.8 years for the microsurgical group, which is probably correlated to the recent development of the MSD procedure. The minimum time to the final follow up was one year. The data was analyzed with respect to the extent and length of surgery, postoperative neurological changes, complications, postoperative mobilization, the time required to resume work, recurrences and final outcome.
Each patient was then assigned to one of five outcome groups using a modifications classification system. The ability to return to previous occupation, the level of physical activity, subjective complaints, the need for analgesics and neurological status were taken into account. The final outcome was classified satisfactory for patients in the excellent, good, and fair groups and unsatisfactory for those in the poor and failed groups. There were no major differences between the groups in age, sex, or occupation. A marginally higher wound rate relating to infection was found in the standard discectomy group (5.1%) vs. the MSD group (2.0%).
The incidence of postoperative catheterization, deep venous thrombosis, and pulmonary embolism were all significantly decreased in the MSD group. The MSD group returned to work sooner and changed occupation less frequently. The recurrence rate was statistically high for the standard discectomy (SD) group as compared with the MSD group. The final outcome scale determined by an objective, impartial observer, indicated a significantly more satisfactory outcome in the MSD group than in the SD group and a significantly greater percentage of patients assigned to the excellent and good categories in the MSD vs. the SD group.
In the self-assessment evaluation, 81% of the SD and 90.6% of the MSD were satisfied with the outcome of their treatment while 18.6% of the SD and 9.4% of the MSD patients were dissatisfied with the outcome.
The authors concluded their findings agree with others in that microsurgical techniques can produce good results. Specifically, they feel the MSD technique can be a safe intervention against lumbar disc disease. Although the literature supporting the advantages of microsurgical techniques is accumulating, the authors noted one must understand the demands, requirements, and limitations of the MSD. Once mastered it requires frequent and meticulous application.
Percutaneous Discectomy: A Patient Panel Study
Kambin et al, reports results of a study of 100 patients who have been treated with percutaneous lumbar discectomy. Fifty-nine of the patients have been followed for two years. The modified MacNab criteria was used in evaluating the results of the surgical procedure. Patients were eligible for the procedure if the following criteria were met:
1. persistent radiculopathy;
2. failure of appropriate conservative treatment (which was undefined);
3. neurological impairment;
4. correlative electromyography in the absence of correlative neurological deficits;
5. positive tension signs; and,
6. correlative imaging signs.
Patients excluded had sequestrated disc herniation, spinal stenosis, reherniation following laminectomy or chemonucleolysis. Post-op examinations were at one, two, and four weeks, then at three, six and twelve months, followed by annual examinations. The follow-up examinations consisted of chart review, physical examination, and patient interview. A six-part questionnaire was filled out by all patients contacted and included detailed questions about activity level, work, amount of pain, and pain relief postoperatively. Specifically the patients were asked about the result of the surgery and if they felt cured, helped but not cured, or about the same.
Of the total 100 patients with 102 discs treated with percutaneous lumbar discectomy, 93 patients were available for follow-up examination. Three patients had died but had been followed for 15 months and four could not be located for the review but had been followed for one year. Fifty-nine patients had been followed for more than two years postoperatively with a maximum of six years. Of the 93 patients available for the following examination, 81(87%) patients with 83 herniated nucleus pulposus were judged a success as they were pain-free and had returned to employment and their pre-injury activity level. These patients stated the procedure was successful in relieving their pre-existing symptoms. Twelve patients (13%) were failures requiring repeat surgical procedures at the level of the presenting pathological condition.
A breakdown of disc levels of pathology shows 10 patients with L3-L4 level with a 90% success rate. Seventy-seven patients at the L4-L5 level with a 90% success rate and, with rationale discussed later, only six patients at the L5-S1 level with a success rate of 50%. The three patients who had died during the follow-up had been reported to have had excellent results in respect to their 15 month follow-up period. Causes of death were unrelated to the lumbar surgery. The authors concluded this technique was valuable along with being safe, cost efficient, and decreasing hospitalization and post-op recovery time.
Lumbar Fusion: A Patient Panel Study
Two orthopedic surgeons report a study of 100 unselected posterior lumbar interbody fusion cases. One hundred patients were chosen at random out of over 900 operated cases. Indications for the operation were relief of low back pain and/or sciatica due to acute disc herniation or degenerative disease. Eleven had a congenital spondylolisthesis with bilateral defect in the pars articularis. Thirty-four were compensation cases. The follow-up was from one to seventeen years (60% for ten years). There were thirty-five females and sixty-five males. The end result figures were the patient’s evaluation of the success or failure of his operation.
They were placed in four categories: excellent, good, fair, and poor. Sixty-four patients placed themselves in the excellent category with no pain whatsoever. Time required to reach maximum recovery was four and one-half to six months. Twenty-six patients were good with occasional backache, but physical activities such as work and play were completely unrestricted. Seven patients were listed as fair, having more occasional pain and some restriction of activity. But in these patients, all were working and self-sufficient. There were twelve patients placed in the poor category, indicating no improvement or worse. The author of the study claims this category included one psychopathic, one chronic alcoholic, one subluxation, and two worker’s compensation cases. Three of these were operated on again at another level with good results.
Much has been written on the use of epidural local anesthetic and steroid in the management of low back pain with sciatica. The primary goal of this form of management is to improve the patient’s quality of life by controlling pain. The placement of corticosteroids around the nerve root may be expected to reduce the inflammation and edema that accompanies it. This partly relieves the pressure along with the inflammation resolving as well. This inflammation immediately stops because of the corticosteroid’s ability to increase the resistance of cells in the inflammatory zone to the cytotoxic action of other agents during inflammation.
This helps interrupt the chain reaction of cellular destruction. If a cell membrane remains too long in a permeable state, the increase in osmotic pressure swells and may possibly burst the cell. Protective agents that can dilute, destroy, or lessen the destructive action of the broken cell, or which will stabilize the unbroken cell, will lessen this inflammation.
Cortisol acts to stabilize the cell in its impermeable state. Local anesthetics stabilize the neuronal membrane and prevent the initiation and transmission of impulses. Sensory, motor, and autonomic blockade depend on the site of the administration, the volume, and the concentration of the local anesthetic.
Epidural injections are commonly used through caudal route for disc herniation at the L4-5 and L5-S1 levels. A translumbar approach is often used for disc herniations L3-4 and above. Localization of the injection is often performed under fluoroscopic guidance. In clinical cases as well as research, the results of the injection are normally assessed at two to three weeks. If disabling pain persists the injections may be repeated. Most physicians agree that two to three may be tried before other intervention is discussed with the patient.
Many feel that if the pain can be controlled, and the natural process allowed to run it’s course, partial or complete resolution of the mechanical factor may occur. The mechanical factor in this case being the disc herniation. Nonetheless, many physicians and researchers well versed in epidural injection therapy agree that there is clearly always a place for surgical decompression of patients when aggressive conservative management fails.
Non-Operative Treatment of Lumbar Herniated Intervertebral Discs: An Outcome Study
A study by Saul et al, wanted to determine whether patients with lumbar disc herniation and radicular pain without stenosis could be treated effectively with aggressive conservative care. A total of 347 consecutive patient records were reviewed resulting in 64 patients selected for the study. Patient criteria were a CT or MRI indicating herniated nucleus pulposus, chief complaint of leg pain, positive straight leg raise test at less than 600, a positive EMG, and response to a follow-up questionnaire. An aggressive treatment program was performed by all patients. This included back school, exercise training to teach spinal stabilization such as maintenance of postural control, trunk and general upper and lower body strengthening exercises, and flexibility exercises. Epidural injections and/or selective nerve root blocks were used when indicated for pain control. The underlying goal of the program was that the patient undergo active, not passive treatment. Symptom duration averaged 4.6 months with a mean follow-up time of 31.1 months. A questionnaire was sent inquiring about activity level, pain level, work status, and further medical care. Patients with a neurologic loss, extruded discs, and those seeking a second opinion regarding surgery were identified and subgrouped. Thirty-six men and twenty-two women returned the questionnaire with a mean age of 35.5. Thirteen were worker’s compensation cases (22%).
Six patients required surgery, leaving 52 non-operative patients classified according to the Oswestry scale. This scale denoted ‘excellent’ as working full-time and performing usual athletic activities; ‘good’ as working full-time but limited in performance of athletic activities; ‘fair’ as working part-time only and unable to participate in athletic activities; and, ‘poor’ as unable to work and unimproved following treatment. Of the total of 52 non-operative patients, 50 with good or excellent outcomes were considered successes (85% of the entire population, and 96% of the nonoperative population), 48 returned to work and 85% returned to their previous jobs. The self- rated reports for these patients were excellent 15 (29%), good 35 (67%), fair 2 (4%), and poor 0 (0%). Both fair scores were worker’s compensation cases.
Eighteen patients made up the second opinion subgroup and were seen for a second opinion regarding surgery. All of these patients had been advised by a surgeon that they needed surgery as soon as possible to avoid long-term complications. Of these, 15 (83%) were non-operative treatment successes, three (20%) scoring excellent on the self-rating reports and 12 (80%) scoring as good. All 100% returned to work with an average sick leave time of 3.4 months. In another subgroup extruded discs were noted in 15 patients (26%). Thirteen were non-operative treatment successes with an average sick leave time of 2.0 months. Nine of the reported cases had less than one week’s sick leave time. The authors concluded this study demonstrated herniated nucleus pulposus of a lumbar intervertebral disc with radiculopathy can be treated very successfully with aggressive non-operative care. Surgery should be reserved for those patients for whom function cannot be restored satisfactorily by physical rehabilitation.
Conservative Preoperative/Postoperative Management Goals
Kisner approaches treatment of lumbar disc herniation with three goals in mind. First to relieve pain and promote muscle relaxation by the use of rest combined with periods of controlled movement and various appropriate therapeutic modalities. Secondly, relieving pressure against pain-sensitive neurologic structures by motions that decrease the size of the bulging disc. The patient must be educated in avoiding positions, exercises, and activities that increase intradiscal pressure. The third goal is to promote positions and movements that align the spine and reduce the intradiscal pressure with patient education and the involvement of a rehab program.22,23 Once symptoms have stabilized, many claim total management often involves passive exercises as soon as they can be done without increasing peripheral symptoms.
One clinical approach, known as centralization of pain, is used by the advocates of the McKenzie-type exercise program. The patient is asked to perform maneuvers that change pain from the lateralized position to the center of the back. Usually the exercise is from neutral to extension but occasionally from neutral to flexion. One comparative study found the McKenzie protocol twice as effective in decreasing low back pain as traction and back schools. Whether the physical therapist chooses to address the rehab around flexion or extension, the appropriate exercise regime must be individualized to each patient.
Post-op rehabilitation of more invasive procedures discussed may begin as early as in recovery when the therapist attaches a TENS unit to the sterile electrodes placed adjacent to the incision prior to the application to the dressings. In all surgical procedures, exercises should begin as soon as possible, starting with walking. However, patients should refrain from bending, lifting, twisting, and driving for four to six weeks. Laminectomy patients are generally discharged with a minor pain medication as well as anti-inflammatory medication and thereafter progress into a gentle aerobic exercise and stretching program. Two weeks post-op muscle strengthening begins in the legs with the incorporation of pushups, followed by flexibility/strengthening exercises and back school.
Over the upcoming weeks, a strengthening program is instituted. In general, the patient is returned to a sedentary type occupation within a week to ten days postoperatively and to more strenuous labor within four to six weeks. Lumbar fusions are often immobilized six to eight weeks in a brace until bone fusions are healed well enough. Yet, during this time the patient is encouraged to do pelvic tilt and straight leg raises, followed two to four weeks later with flexibility strengthening exercises and back school. Patients treated with chymopapain and percutaneous procedures should be as active as possible however, patients may experience minor back pain associated with settling and inflammation. Occasional muscle spasm and pain are experienced after chymopapain procedure and often receive muscle stimulation for pain control.
The reviewed procedures of lumbar nerve root decompression demonstrated favorable results as follows: microdiscectomy; 90%, standard discectomy; 81%, percutaneous surgery; 78% (includes laser surgery), chemonucleolysis; 67% and lumbar fusion; 64%. All of the studies appeared to have reasonable follow-up periods which may have aided in portraying more accurate/realistic success rates than often seen in various literature reporting as high as mid to upper 90 percentile success rates.
However, post-op evaluation criteria determining these success rates varied among the studies. The McNab response to treatment was used in the percutaneous laser and percutaneous discectomy studies. The MSD vs SD used an objective evaluation from a third party along with patient self-evaluation forms. The lumbar fusion outcome was based on the surgeon’s analysis along with the patient’s evaluation determining surgical success or failure. This raises the question that perhaps the differences in success rates of studies presented may be predominantly a result of variability of post-op success criteria. A 60% success rate may indicate a more rigorous success criteria compared to a study with 90% success rate using a more general criteria which may be easier to score high. Conservative measures in relation to patient selection criteria were not similar among the studies and in some ways quite vague.
For example, the percutaneous laser study and the MSD vs. SD study categorized physical therapy along with bed rest, analgesics, and muscle relaxants as components of conservative treatment. It was not explained what the physical therapy consisted of, nor the duration. The percutaneous discectomy and lumbar fusion study did not define conservative treatment, posing the question if physical therapy was attempted at all. Classification of selected disc herniations was similar among the percutaneous procedures and chemonucleolysis. All procedures needed herniations defined within the disc. The far lateral disc herniations are noted to do poorly under percutaneous discectomy.
Contraindications for all percutaneous procedures include recurrent disc herniation after previous laminectomies, spinal stenosis, spondylolythesis, anklylosing, and spondylosis.
The L5-S1 levels were considered a difficult level for all percutaneous instruments to enter because of the change in angle between these segments. However, it should be noted this is a common level of herniation which may strongly affect the usefulness of this procedure. Risks of percutaneous procedures noted are psoas hematomas and cauda equina injuries but were results from inexperienced surgeons. Conventional discectomy can be useful nerve root decompression but is noted to have a 90% success ‘short term’ rate declining to 60-70% the next subsequent decade with 5-15% requiring another surgery. This is thought to be related to recurrent disc herniation or initial failure to recognize stenosis of the nerve root canal.
Fusions are the most surgically invasive but can help in restoring stabilization. Chemonucleolysis should be reserved for a limited number of patients who have not had previous surgery. Other contraindications include allergies to papaya, previous injections with chymopapain, severe cauda equina, neurologic disorders, children under 14 and pregnant women.
Risks also include the difficulty of the L5-S1 needle placement. Arthroscopic surgery is not for elderly patients with narrowed and degenerated intervertebral discs or patients with symmetrical bulged and annular fibers. Microdiscectomy is best accomplished at a single level radiculopathy, but can be easily converted to the traditional discectomy if indicated. The use of undefined conservative treatment in the literature raises the question if physical therapy was being utilized to its fullest extent before surgical intervention.
The non-operative study showed 96% had excellent outcomes with an interesting 83% success rate for patients who were advised to have surgery. Based on this information, physical therapy should be given more priority in the realm of conservative treatment. In order for this to happen, physical therapists need to become more active in proving what the profession can do for the patient experiencing lumbar nerve root compression. This can be done through more clinical research which will help educate many members of the medical profession regarding the strong potential we have in the intervention of lumbar disc herniation.
Less invasive lumbar disc decompression surgical techniques are becoming increasingly popular. With this trend, healthcare professionals must keep up with the latest procedures to help in the rehabilitation of the patient. It must be emphasized that any and all surgical intervention should be the last resort for the patient. Before comparing success rates of lumbar nerve root decompression approaches, one needs to recognize the different criteria used in patient selection and post-op evaluation criteria evaluation.
Studies show aggressive conservative therapy can be very successful in the treatment of the lumbar herniated disc. In the non-operative study, it was concluded that a herniated lumbar disc producing radiculopathy can be treated successfully with aggressive conservative care and suggesting that surgery should be reserved for those patients where function cannot be restored satisfactorily by physical rehabilitation. With continued research and advancements in surgical techniques, plus an increased awareness of the role of physical therapy, hopefully we will see an end to the failed back syndrome.