Section 18, Chapter 3: Recurrent Stenosis – Diagnosis and Management

Section 18, Chapter 3: Recurrent Stenosis – Diagnosis and Management

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Section 18, Chapter 3: Recurrent Stenosis – Diagnosis and Management

Angus Don

INTRODUCTION

Stenosis is the narrowing of a hollow tube, or in this case, the spinal canal in the lumbar spine, either centrally, in the lateral recess or in the foramen, or a combination. Recurrent stenosis is narrowing of the spinal canal which has already been decompressed in the past. Clinically, this narrowing and compression of the neurovascular structures may present as pain with neurogenic claudication, radiculopathy or mechanical back pain. With recurrent stenosis, the clinical pattern may be similar to the patient’s presentation prior to their previous surgery or it may be a complex of old and new symptoms.

The evaluation of the patient with recurrent stenosis requires an in-depth assessment of their current and previous symptoms, a detailed history of the type and adequacy of the previous surgery, and then matching this to their imaging. These factors need to be analyzed in respect to why the stenosis has reoccurred. Is there an unrecognized biomechanical issue? Was the initial surgery adequate? Finally, incorporation of these elements need to be taken into the equation before planning further surgery.

Surgery for recurrent stenosis represents its own challenges. Scarring and fibrosis increase the challenge of maximizing an adequate decompression and combine with the need to ensure stability and optimal alignment of the spine. Ideally, any spinal surgery will be the patient’s last, and optimizing revision strategies will minimize the chance of failure in the future.

HISTORY AND EXAMINATION

Patient History

As with assessment of all spinal patients, the history and examination provide a key to understanding the patient’s current problems, assessing their disability and optimizing treatment for the future.

Overview: It is a useful technique to enable the patient to recount the history of their lumbar issues from the initial evolution through to their current situation. This history should start with the initial onset of symptoms and whether there was a triggering event or accident. It is useful to evaluate the initial symptoms: were they back pain dominant or did they present with classical neurogenic claudication? Treatments should be discussed, with an evaluation by the patient of the efficacy of each treatment. Particular consideration should be given to any injections that were performed as well as where they were performed – that is, facet blocks, epidurals or nerve root injections. The patient should also report the different medicines that have been tried as well as ancillary services, physiotherapy, chiropractic, and osteopathy to allow the clinician to assess the extent of non-operative management they have received.

With recurrent stenosis, a detailed history of all previous surgery that has been performed is essential. Knowledge of the patient’s symptoms prior to their initial surgery is useful in establishing whether they now present with a similar or dissimilar problem. The nature of the previous surgery should be noted, with the levels addressed and records of any complications that occurred. Dural tear or wound issues at the time of the original surgery may influence future surgery. For example, if there has been a posterior wound infection in the past, consideration may be given to anterior interbody surgery to indirectly decompress the foramen and avoid going through the previously contaminated field.

Ideally, obtaining the original operative note and clinical follow-up will enable assessment of the patient’s improvement following the initial surgery. It will also allow assessment of any implants that have been inserted so that the correct equipment can be ordered if it becomes part of the revision strategy.

The length of time the patient had resolution of their symptoms can provide an important clue as to the current pathology. Early recurrence of symptoms may represent an unrecognized and untreated biomechanical or instability factor that has resulted in recurrence of the stenotic symptoms. It may also represent an adjacent segment problem above a previously fused level. Similarly, later presentation of symptoms with sustained relief in the intervening period may also represent an adjacent segment problem or recurrent stenosis at the same level as the index procedure.

Current Symptoms: With recurrent stenosis it is important to establish how current symptoms compare to the symptoms noted prior to their previous surgery. Do they present with a similar pattern of neurogenic claudication or do they have an increased back pain component of their symptoms, which may represent increased degenerative change or new instability? With any history related to stenosis it is vital to differentiate between vascular and neurogenic claudication. While leaning on a walker or shopping cart may be characteristic for lumbar spinal stenosis, it may also represent disease in the posterior elements that is unloaded with a flexed posture. Up-to-date treatment modalities that have been employed also need to be evaluated. As with all spinal histories it is important to both exclude any red flags and ask about any sphincter dysfunction.

General Medical History: An evaluation of the patient’s overall medical status to assess comorbidities will enable the clinician to assess their fitness for further interventions. Included in this should be a smoking history and use of anticoagulation medications. If there are significant comorbidities, assessment by a specialist in perioperative medicine is useful to determine their fitness for surgery. If the patient is not fit enough to have the right operation they are definitely not fit enough to have the wrong operation.

Employment and Activity Level: Knowing the patient’s current status in terms of work and employment is useful to gauge the characteristics and expectations of the individual. It will also enable the clinician to provide realistic expectations regarding the level and timing of return to work following any procedures. Activities such as sporting and leisure activities, as well as what activities the patient cannot currently accomplish, can provide a useful guide as to the patient’s current disability and fitness to recover.

Clinical Examination

The examination of the spine is well established. Classically the examination of the spine in lumbar spinal stenosis may reveal very little. Often patients will have decreased lumbar extension and decreased or absent ankle and/or knee reflexes. However, in the case of recurrent stenosis, the examination plays a much more important role in diagnosis and charting the course for future intervention.

Overview: As with any examination, appropriate exposure of the patient is necessary – often a surgical gown is useful. Watching the patient enter and leave the consultation area provides useful insights. The use of a walker or walking aid may be an indication of significant stenosis or sagittal imbalance. Observing a patient sit and rise from a chair, if painful, may give a clue to segmental instability. Occasionally, over-exaggeration of symptoms may be present on arrival but improve upon departure. Noting the previous scars, location, and skin quality is useful if the patient has undergone multiple spinal procedures, and if these indications are poor may necessitate the use of different skin closure techniques such as suction dressings.

Assessing sagittal alignment when the patient stands with knees extended allows determination of whether a sagittal malalignment issue may play a role in the recurrent stenosis. Clinicians need to be aware that the patient in the office will try their best to stand erect and may underrepresent their normal posture with fatigue. Gait patterns will provide a clue to new or old muscle weakness, such as a foot drop. Heel and toe gait gives a gross assessment of gastrosoleus and tibialis anterior strength respectively.

Lumbar range of motion is noted, and as noted previously, extension is often limited due to the stenosis and associated posterior element disease. Flexion is generally maintained, but decreased flexion may represent either lumber disc disease or loss of hip motion. Pain with flexion or extension or both may provide further clues to the pain generator.

Neurological Examination: Thorough neurological examination of the patient is essential in cases of recurrent stenosis, especially when revision surgery is planned. Careful documentation of strength, sensation and reflexes of the lower extremities can document long-standing deficits or recently developed problems.

Other Systems: Claudicant symptoms may reflect a neurogenic cause or vascular cause, and therefore a vascular cause needs to be excluded from the diagnosis – careful evaluation of peripheral pulses is mandatory in this regard. Hip pathology and other rheumatological conditions which may mimic stenosis such as polymyalgia rheumatica also need to be assessed as possible causes of pain and disability.

IMAGING/INVESTIGATIONS

Imaging and investigations play an essential role in the evaluation of a patient with recurrent stenosis. It is not simply a matter of repeating the MRI scan and heading straight to the operating room. Assessment of possible reasons why the stenosis has reoccurred need to be evaluated and balanced with any other new symptoms. Good planning prior to any intervention optimizes the chance of a successful outcome for the patient and minimizes the chance of problems in the future. It is likely that several imaging modalities may be useful when establishing the patient’s current problem. Starting with X-rays, it would be routine to include a MRI and CT in the course of the patient’s workup. Nuclear imaging such as a SPECT scan or bone scan may be used depending on the patient’s symptoms. Nerve conduction studies or nerve and facet blocks may also provide useful information.

Radiographs

Erect lumbar spine X-rays are the first investigation which is required when evaluating an individual with recurrent stenosis. The X-ray is often bypassed with clinicians heading straight to an MRI. However, the X-ray will provide valuable information. Firstly, it will allow correct identification of levels and allow assessment of transitional levels, which can be miscounted if relying on MRI alone. The levels on the X-ray need to be cross-referenced with the MRI to determine what levels need to be addressed. Secondly, erect X-rays allow for detection of dynamic instability that may not be present on supine films or the MRI scan. The MRI taken in the supine position may underrepresent the amount of stenosis present, but when it is assessed in the light of the instability or listhesis, the clinician can get a better understanding of the severity of the problem. It will also affect surgical planning, with the instability often requiring a fusion as opposed to decompression. Finally, erect X-rays and, in particular, full-length standing views will allow assessment of the patient’s overall sagittal and coronal alignment. This alignment needs to be taken into consideration when planning any revision surgery, especially when a fusion has been part of the original surgery. Hypolordosis of the lumbar spine and fused segments have been demonstrated to be a risk factor for adjacent segment deterioration in several studies as leading to recurrent stenosis. Full analysis of sagittal alignment is beyond the scope of this chapter.

Magnetic Resonance Imaging (MRI)

MRI is the mainstay of the evaluation of spinal stenosis and recurrent stenosis. The increase in the number of sequences that are available and the addition of gadolinium provides the majority of the information when planning surgery. The MRI needs be evaluated for the degree of stenosis at each level and the number of levels involved. T2 sequences will provide the majority of this information, allowing the clinician to assess the amount of stenosis centrally and in the lateral recess. T1 sagittal images provide useful information about foraminal stenosis. The nerve root is surrounded by fat in the foramen and this fat layer, when eliminated, can indicate stenosis and nerve root compression. In the light of previous surgery, the addition of gadolinium to the sequences allows assessment of the degree of epidural fibrosis that is contributing to the stenosis and its contribution to the patient’s symptoms. The MRI can also determine which levels have previously been operated on if no past history or details of the original surgery are available.

Computerized Tomography (CT)

CT is generally not necessary in evaluating spinal stenosis in patients who have not had surgery in the past, however in recurrent stenosis it is a useful adjunct to surgical planning. CT gives excellent visualization of the bony anatomy. This allows clear assessment of the amount of bony resection that has previously been performed. With this knowledge, the surgeon can decide whether it is safe to resect more of the facet as part of the decompression without causing iatrogenic instability. It also allows the surgeon to determine where the lamina or posterior elements have been removed completely, and so at which level caution will be required in the dissection. When revision decompression is required with an adjacent fusion, it determines whether the previous fusion is solid or whether the fusion also needs to be addressed at the time of surgery.

Myelography

While myelography has fallen out of favor with the advent of MRI, it still has a useful role to play. In evaluating recurrent stenosis, it can be very useful when the patient has metalware in situ, especially if it is stainless steel and the artifact obscures any useful information on MRI. The other important use for myelography is when the patient has a contraindication for MRI – heart pacemakers (especially older types), insulin pumps, implanted hearing aids, neurostimulators, intracranial metal clips or metallic bodies in the eye.

Single Photon Emission Computerized Tomography (SPECT), and Positron Emission Tomography (PET)

While not strictly useful to assess stenosis, the SPECT or PET scan which demonstrates areas of increased ‘bone activity’ can play an adjunct to revision surgery. These scans can provide clues to possible pain generators that may contribute to the patient’s current symptoms. These scans are especially useful to determine facet disease that not only contributes to the stenosis but also causes back pain-related symptoms. The scans would then play a role in surgical decision-making as to whether specific levels need to be fused as part of the revision surgery.

Additional Tests

Depending on the clinical presentation, various additional tests may be required to determine whether the patient is suffering from recurrent stenosis or another condition with similar features. In this regard, investigations need to be tailored to the individual. Tests which may be included include X-rays or other imaging of the lower extremities (hips, knees, etc.), blood tests to exclude rheumatological conditions, nerve conductions studies and EMG to exclude or diagnose a peripheral neuropathy, and nerve or facet blocks to help clarify the source of the pain. This list of tests provides a guideline but is not exhaustive.

NON-OPERATIVE MANAGEMENT

As with most orthopaedic or spinal conditions, the initial mainstay of treatment is non-operative management. However, few high-quality randomized trials have investigated non-operative management strategies for lumbar spinal stenosis, let alone recurrent disease. The extent of non-operative management will depend on a number of factors. First, the patient’s current level of symptoms and incapacity. If the patient has symptoms which are annoying and an inconvenience, they are far more likely to maximize non-operative management, as opposed to the individual who has severe chronic pain which affects their function and compromises their quality of life. The next important factor to take into consideration when looking at someone with recurrent stenosis is their outcome from their previous surgery. If the individual had a good improvement from their previous surgery, with resolution of their symptoms and long-lasting results, then another surgery might be looked on more favorably compared to an individual who had an initial stormy post-operative recovery, with possible complications or incomplete relief of their symptoms and early deterioration. In the latter case, a longer non-operative period may be justified. Non-operative treatment is also an important modality for those for whom surgery poses significant risk of morbidity or mortality. In this situation, optimizing their analgesic regime and the use of a walking aid may be the best solution.

Analgesics

Common Analgesics: Recurrent spinal stenosis is generally a painful condition that causes back and leg symptoms. Consistent with this pain is the usual treatment with analgesics to control the symptoms. Although various over-the-counter and prescription drugs are used to treat lumbar spinal stenosis, the evidence to guide choices is limited. The World Health Organization generally advocates using a step-wise approach to pain management, the so-called “pain ladder,” and this remains true for recurrent stenosis.1 Common analgesics is a broad term which covers medications such as NSAIDs (non-steroidal anti-inflammatory drugs) as well as simple analgesics. The term “common” helps differentiate them from opioid analgesics.

  • Simple analgesics: Acetaminophen is a first line agent that possesses both analgesic and antipyretic properties.
  • NSAIDs: NSAIDs function through various degrees of blockade of COX isoenzymes, thus blocking the inflammatory cascade of arachidonic acid to prostaglandins, which mediate inflammation and sensitize peripheral nociceptors. They have both analgesic and anti-inflammatory properties. Evidence suggests that they be no more effective than acetaminophen.2,3

Opioid Analgesics: Opioid analgesics cover those medications that act on the opioid receptors.  They may be divided into weak opioid analgesics such as codeine (often combined with acetaminophen), and strong opioid analgesics. The role of opioid use in recurrent spinal stenosis remains unclear. It has also been suggested that prostaglandin E1 may improve symptoms by improving blood flow to the cauda equina and nerve roots through vasodilation and antiplatelet aggregation effects.4

Adjunctive Analgesics: This term is used to describe analgesics that are used for pain relief but whose primary role is not that of analgesia. This group includes both antidepressants and antiepileptics. In the antidepressant group the most commonly used drugs for stenosis are the tricyclic antidepressants, such as amitriptyline, which are thought to provide pain relief for neuropathic pain via the serotonergic and noradrenergic pathways, possibly due to their stabilization effects on nerve membranes. In terms of antiepileptics, it is the second-generation drugs that are used for the treatment of claudicant and neurogenic pain that is seen in spinal stenosis and recurrent stenosis. These drugs include gabapentin and pregabalin which act on voltage-gated calcium channels and inhibit excitatory neurotransmitter release. There is some evidence that gabapentin can improve walking distance and decrease the intensity of low back pain and/or leg pain in patients with lumbar spinal stenosis.5

Physiotherapy

Physiotherapy is a popular modality used in the non-operative management of recurrent lumbar spinal stenosis, with treatments including but not limited to:6

  • Exercise (aerobic, strength, flexibility)
  • Specific exercises in lumbar flexion (cycling)
  • Body weight supported treadmill walking
  • Muscle coordination training
  • Balance training
  • Lumbar semi-rigid orthosis
  • Braces and corsets
  • Pain relieving treatments (heat, ice, electrical stimulation, massage, ultrasound)
  • Spinal manipulation
  • Postural instruction

The evidence to support the use of physiotherapy in lumbar spinal stenoses is weak, and in recurrent stenosis non-existent. However, the role of physiotherapy may be to improve the patient’s overall function as opposed to treating the spinal stenosis itself. Preliminary results from a lifestyle intervention may indicate that weight loss and increased exercise may reduce symptoms and improve function in people with lumbar spinal stenosis.

Injections

Epidural injections are another commonly used modality in the management of lumbar spinal stenosis, but are less commonly used in the setting of recurrent stenosis as scarring around the dural sac often eliminates the epidural space. Any evidence for use in recurrent lumbar spinal stenosis is based on treatment of primary lumbar stenosis and the results vary. Overall, some studies demonstrate some improvement in symptoms over the short term, while others demonstrate no effect compared to placebo. Long term improvements in pain and walking distance with epidural steroids is not supported by the literature.

Alternative Modalities

There are a large number of alternative and complementary practitioners who purport to treat and help individuals with stenosis, including osteopaths, chiropractors, acupuncturists, practitioners of craniosacral therapy, etc.  There is no evidence for the use of these modalities in individuals with recurrent lumbar stenosis.

The Walking Frame

A walking frame or walker is a device which enables an individual to walk in a flexed posture and still maintain their balance. This is an extremely valuable piece of equipment that can help improve claudicant symptoms in someone with recurrent spinal stenosis. The flexed posture of the lumbar spine allows the central canal to open and hence improve symptoms. It is equivalent to the classic ‘leaning on the shopping trolley’. It is especially useful for patients whose comorbidities preclude further surgery or who do not want to proceed down the surgical pathway. The downside of the walking frame is that patients feel it stigmatizes them as an old person.

SURGICAL MANAGEMENT

Once the patient has exhausted non-operative management and their radiology, clinical history and examination are consistent with a diagnosis of recurrent stenosis, then the decision for surgery can be made. What type of surgery to perform is based on the location of the stenosis, the degree of stability within the lumbar spine, overall sagittal balance and associated painful degenerative levels.

If the basis of the recurrent stenosis has no element of instability, sagittal imbalance that needs to be addressed or associated back pain that requires fusion, the next step is to establish the location of the stenosis to be addressed. If the stenosis is predominantly in the lateral recess, then revision laminectomy and decompression is the procedure of choice. If the stenosis is foraminal, then consideration needs to be given to indirect decompression especially if it is on a cranial-caudal basis. This is best accomplished through an interbody device inserted from a variety of approaches including posteriorly, laterally or anteriorly. Often this may be a good option to avoid operating through a scarred surgical bed. If, however, the foraminal stenosis is in an anterior to posterior direction, then direct decompression may be required. While indirect decompression may provide some decompression in the AP direction, it is generally less effective than cranial-caudal decompression, especially where there is scar tissue or bony overgrowth.

Contrary to surgery for decompression alone, is if there is evidence of instability, or if the revision decompression will resect so much facet that it renders the segment unstable, then the decompression will be best combined with a fusion. The technique for this combination will vary from surgeon to surgeon. Similarly, if there is sagittal imbalance that is clinically problematic, then this too will need to be addressed at the same time as the revision decompression.

The association of back pain with recurrent stenosis is slightly more controversial.   Generally, a group of patients with these complaints would include individuals that have significant symptomatic degenerative disc disease or facet arthrosis which has been confirmed on imaging, such as MRI or SPECT and/or have had a response to injections such as facet blocks or discography. The results of fusion for back pain have been well established and these results need to be discussed prior to embarking on surgery to address recurrent stenosis and back pain.

As with any surgery, informed consent should be undertaken, highlighting the increased chance of complications compared to primary surgery. Complications could include, but are not limited to, dural tear, neural injury, infection, iatrogenic instability, epidural fibrosis, as well as failure to relieve pain. These complications will be addressed in another section of this text.

Surgical Technique

Laminectomy/Revision Decompression

Patients are fitted with thromboprophylactic device, TED stockings or sequential calf compressors (SCC). The patient is placed under a general anesthetic. One dose of IV antibiotics is administered. An indwelling catheter is inserted if prolonged surgery is anticipated or if patient will be slow to mobilize. Patient is turned prone onto a support which allows mild lordosis such as padded rolls or a Wilson frame that has not been wound up to maximum height. Abdomen must be free to prevent venous distention and reduce epidural bleeding. Loupe magnification or microscope is recommended.

The old incision is generally opened and extended proximally or distally as required.   With preoperative planning, note will have been made on the CT as to where the posterior elements were deficient from the previous surgery. A submuscular approach is then used to initially approach an area that has a known intact posterior lamina.  This area may be cranial or caudal to the area to be decompressed. From this starting point, the surgeon should carefully dissect using diathermy to define the margins of the previous decompression, taking care to preserve the facet capsule. The pars interarticularis also needs to be defined to enable the extent of the fusion to be determined and prevent iatrogenic pars defect.  Next, a small curved curette is used to release the scar tissue from the bony elements, which enables a Kerrison punch to be placed safely under the bony margin to expand the laminotomy/laminectomy. A burr may be useful at this stage to thin bony elements that need to be resected.  Resection is carried proximally and distally until unscarred and non-stenotic segment of dura is reached. Scar tissue and ligamentum flavum may then be dissected off the dura. The use of a non-toothed forceps to hold the scar tissue and a Watson-Cheyne or Penfield four to carry out the dissection is a useful technique. It should be noted that with revision, decompression scar tissue may be densely adherent to the dura and may not be able to be removed with a clear plane. In this situation the scar tissue can be debulked with sharp dissection using a fifteen blade and the lateral recess decompressed until the dura is soft with no ongoing compression. Up to 50% of the original facet can be removed, carefully noting how much remained after the initial surgery. The extent of the lateral recess decompression can be determined when the pedicle can be clearly palpated with no residual stenosis. Foraminal decompression can be performed until a Watson-Cheyne can be passed freely out the foramen. It is worth noting that with scar tissue and epidural fibrosis, the nerve roots may not have the ability to be retracted easily, and over-vigorous nerve root retraction in this situation may result in iatrogenic neural injury.

Once sufficient decompression has been achieved, the wound is washed out with normal saline. A low suction drain may or may not be used. The wound is closed in layers. Mobilization commences day one post-operatively.

Indirect Decompression

The traditional treatment for symptomatic recurrent lumbar stenosis has been by direct posterior decompression as described above. However, the stenotic symptoms may also be alleviated indirectly, through correction of intervertebral and foraminal height and correction of spinal alignment. Anterior or lateral interbody spinal procedures rely on this indirect decompression when used in patients with radicular symptoms. These techniques are particularly valuable in the setting of cranial caudal foraminal stenosis where there is good evidence that either an anterior or lateral interbody device provides significant foraminal decompression.7,8 They also allow good foraminal decompression without having to reoperate through a scarred field.

There is also some evidence in the primary operation that indirect decompression may cause an increase in the central canal diameter – however, there is limited evidence for this in the revision situation. With associated scarring, it is likely that indirect decompression for central stenosis would not be as effective as in that of the primary situation.

The individual techniques for anterior and lateral interbody surgery are beyond the scope of this chapter.

Revision Decompression Combined with Fusion

Fusion may need to be combined with revision decompression for a number of reasons, including instability, sagittal imbalance, or back pain. The techniques for the fusion will vary depending on the relative indications. However, the technique for posterior decompression, excluding that of indirect decompression, remains basically similar to the laminectomy described above, barring the fact that as much of the facet complex can be removed as necessary to facilitate decompression and address the underlying cause for the fusion.

RESULTS

While the successful results for primary spinal stenosis decompression are well documented, the literature for revision surgery of recurrent spinal stenosis is scarce. The results for revision lumbar disc herniation have demonstrated good or excellent results, while stenosis from other causes including facet hypertrophy, epidural fibrosis or osteoarthritis remain less clear. Medenhall et al. looked at 53 patients with recurrent same-level stenosis not due to a disc prolapse and treated all with revision decompression and fusion.9 In their two-year longitudinal study, they demonstrated significant improvement in patient assessed outcomes. In all cases, posterior instrumented fusion was performed due to mechanical back pain from post-laminectomy instability or concern for iatrogenic instability with revision surgery.

There is a paucity of literature on revision decompression for spinal stenosis, excluding recurrent disc, which have not had concomitant fusion.

COMPLICATIONS

The rates of complications for revision spinal surgery are all increased compared to that of the primary surgery in the treatment of spinal stenosis.  The risk of complications can be minimized with good preoperative planning and meticulous surgical technique.

Dural Tear

Dural tears are common complications following lumbar spinal surgery and the rate of complication increases for revision surgery. The durotomy incidence in a group of patients who underwent revision surgery was 25% (29 of 116) and was not associated with the years of experience of the surgeon performing the procedure.10 The difficulty arises on occasion when, due to the scar tissue, the dural tear may be difficult to repair. Ideally, a direct repair with a 4-0 to 6-0 running suture should be utilized. The closure should be tested with a Valsalva maneuver up to 40 mmHg. When a direct repair is not possible, other techniques for dural repair, including the use of patches, fat grafts and fibrin glues, may need to be utilized. The patient is then nursed supine for the first 24 to 48 hours post operatively. If a dural tear is recognized and treated appropriately, then there are unlikely to be any long-term consequences.

Iatrogenic Instability

While the incidence of iatrogenic instability following laminectomy is a well-recognized complication, postoperative instability after lumbar decompression remains one of the primary motivators for the performance of a fusion either during the index procedure or in reoperations after decompression. In a comprehensive literature search, the overall incidence of new or increased postoperative spondylolisthesis was 5.5%, with a reoperation rate for instability of 1.8%.11 The incidence is likely to increase following revision surgery when further resection of the facets is required. In the preoperative planning stage, note should also be made of the facet orientation, as more sagittally-orientated facets will limit the amount of resection possible and so may require a fusion with the revision decompression.

Infection

Post-operative infection can cause significant morbidity to the patient, often requiring further surgery, prolonged hospital admission, long term antibiotics and a significant increase in cost. The use of prophylactic intravenous antibiotics should be used routinely. In a study on surgical site infections, approximately one-third of the cases involved revision surgery, with methicillin-resistant staphylococci the most likely organism.12 The suggestion of perioperative vancomycin should be considered.

Failed Back Surgery Syndrome

The cause of ongoing pain following surgery for recurrent stenosis can be a difficult problem to diagnose and manage. Obvious causes need to be eliminated first as a source of pain, including wrong level surgery, incorrect diagnosis and inadequate decompression, which can be confirmed on repeat MRI.

Epidural Fibrosis is one of the more common causes of failed back pain syndrome which can lead to ongoing back or leg pain or neurological deficit. Diagnosis is made with MRI with gadolinium. There are a number of strategies to try and prevent epidural fibrosis, but most are in the experimental phase. Once diagnosed it can be a difficult problem to manage, with non-operative management the mainstay of treatment.

CONCLUSION

Recurrent stenosis can produce an increased number of challenges and difficulties compared to primary spinal stenosis. With a thorough assessment including history, examination and imaging findings, a satisfactory management plan can be instituted to manage the individual patient, whether this be operative or non-operative. Operative management can produce its own challenges; however, careful preoperative planning to assess the role of concomitant pathologies, location of stenosis and extent of previous surgery generally will result in successful outcomes.   While the nature of revision spinal surgery increases the associated risk of complications, for a well-informed patient, surgery for recurrent stenosis is a viable alternative.

REFERENCES

  1. World Health Organization. Cancer Pain Relief. 1st ed. Geneva, Switzerland: World Health Organization; 1986.
  2. Atlas SJ, Delitto A. Spinal stenosis: surgical versus nonsurgical treatment. Clin Orthop Relat Res. 2006;443:198-207.
  3. van Tulder MW, Scholten RJ, Koes BW, Deyo, RA. Non-steroidal anti-inflammatory drugs for low back pain. Cochrane Database Syst Rev. 2000;(2):CD000396.
  4. Shirasaka M, Takayama B, Sekiguchi M, Konno S, Kikuchi S. Vasodilative effects of prostaglandin E1 derivate on arteries of nerve roots in a canine model of a chronically compressed cauda equina. BMC Musculoskelet Disord. 2008;9:41.
  5. Kasimcan O, Kaptan H. Efficacy of gabapentin for radiculopathy caused by lumbar spinal stenosis and lumbar disk hernia. Neurol Med Chir (Tokyo). 2010;50(12):1070-1073.
  6. Lurie J, Tomkins-Lane C. Management of lumbar spinal stenosis. BMJ. 2016;352:h6234.
  7. Rao PJ, Maharaj MM, Phan K, Lakshan Abeygunasekara M, Mobbs RJ. Indirect foraminal decompression after anterior lumbar interbody fusion: a prospective radiographic study using a new pedicle-to-pedicle technique. Spine J. 2015;15(5):817-824.
  8. Oliveira L, Marchi L, Coutinho E, Pimenta L. A radiographic assessment of the ability of the extreme lateral interbody fusion procedure to indirectly decompress the neural elements. Spine. 2010;35(26 Suppl):S331-337.
  9. Mendenhall SK, Parker SL, Adogwa O, et al. Long-term outcomes after revision neural decompression and fusion for same-level recurrent lumbar stenosis: defining the effectiveness of surgery. J Spinal Disord Tech. 2014;27(7):353-357.
  10. Smorgick Y, Baker KC, Herkowitz H, et al: Predisposing factors for dural tear in patients undergoing lumbar spine surgery. J Neurosurg Spine. 2015;22(5):483-486.
  11. Guha D, Heary RF, Shamji MF. Iatrogenic spondylolisthesis following laminectomy for degenerative lumbar stenosis: systematic review and current concepts. Neurosurg Focus. 2015;39(4):E9.
  12. Abdul-Jabbar A, Berven SH, Hu SS, et al. Surgical site infections in spine surgery: identification of microbiologic and surgical characteristics in 239 cases. Spine. 2013;38(22):E1425-E1431.