A new management strategy in reopening laminectomies for cases with spinal canal stenosis

Patient selection and study period

The current retrospective observational study has enrolled 30 patients who had previously undergone decompression laminectomies for the treatment of lumbar spinal canal stenosis and undergone surgical reoperation between November 2012 and November 2018, pegged on an eligibility criterion of those with persistent symptoms of nerve root compression despite seven months of conservative management or with recurrent symptoms within 1 to 4 years following their initial surgery.

The setting of this study was Baghdad Neuroscience Hospital, with clinical diagnosis and EMG confirmation of nerve root compression. This study followed the STROBE guidelines for observational studies.²

No statistical analysis either inferential or otherwise was carried out in this study. Actually, only descriptive statistics on the patient outcomes that included pain score, functional status, and walking distance were used in the study. This is because of the retrospective nature of this study with relatively limited sample size.

Preoperative assessment

Each patient was subjected to detailed preoperative evaluation by clinical examination and EMG studies to establish the diagnosis of nerve root compressions. Imaging studies are used to locate the exact site of foraminal stenosis and preoperative planning. Details of the patient’s history, along with surgical outcomes of previous operations, were taken for planning the intervention accordingly.

Biases and size of study

Few biases were expected since diagnosing and performing with uniform techniques for all patients were considered in the prospective study. Reoperations were carried out by the same surgical team that had undertaken the initial procedures. A study size of 30 patients was adequate, considering prevalence and the volume cases handled by the institution. Data collection was from consistent medical records of the patients, EMG results, and follow-up for all groups.

Surgical technique

The procedures performed were foraminotomies, which were clinically executed and verified using EMG-nerve root compressions. Consequently, a careful and detailed surgical approach was undertaken based on the patient’s anatomical findings and clinical condition. Methods of performing surgery Here are some important recommendations for the surgical technique: 1) Anesthesia and Positioning: The patients were administered anesthesia and placed in a face-down posture on the operating table. The pressure points were adequately cushioned to prevent the development of pressure ulcers and nerve damage. 2) Incision and Exposure: A vertical cut in the center of the lower back was performed, allowing access to the lumbar spine. The outermost layer of tissue was carefully separated to reveal the bony plates of the vertebrae, being cautious not to harm the surrounding soft tissues and muscles. 3) Foraminotomy Procedure: Foraminotomy was done by decompression of the nerve roots with rongeurs and a motor drill. This primarily involved removing bone and soft tissue impinging on the nerve roots at the intervertebral foramina. Guidance and accuracy were obtained by intraoperative fluoroscopy in conducting the decompression. 4) Hemostasis and Closure: Meticulous hemostasis was done and the surgical wound was closed in layers with absorbable sutures for deep tissues and non-absorbable sutures for the skin.

Postoperative care

Following surgery, patients were managed for pain, underwent physiotherapy sessions, and were followed up regularly. Patients were observed for any signs of complications, and their recovery process was recorded. Follow-up was planned for 1-, 3-, 6-, and 12-months post-surgery and periodically after that, as required by the individual progressions of patients.

Outcome measures

The outcome measures recorded in this study included objective pain scores, the Carnovsky rating scale for functional status, and walking distance before the onset of pain.

Systematic review

The systematic review follows Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines (Figure 1)³ and involves a thorough literature search using Scopus and PubMed to identify studies on reoperation rates after decompression with or without fusion for lumbar spinal stenosis. The search was conducted without restrictions on language or geography, and it utilized a combination of relevant keywords and MeSH terms, such as “lumbar spinal stenosis,” “reoperation,” “decompression,” and “fusion.” Boolean operators were applied to refine the search, and filters limited the results to studies on human subjects.

Figure 1. PRISMA flowchart of the included studies.

Inclusion criteria consisted of studies with adult participants with a diagnosis of lumbar spinal stenosis, subjected to any decompression surgery with or without fusion, where reoperation rates or related outcomes had been reported. More specifically, it included retrospective and prospective cohort studies and RCTs. Exclusions included studies unrelated to lumbar stenosis, and those with no specific data on reoperation rates, case reports, editorials.

The selection process began with an initial number of studies, followed by duplicate removal. Two independent reviewers screened the titles and abstracts for relevance, resolving disagreements through discussion or by consulting a third reviewer. Full texts of potentially relevant studies were evaluated, and five studies were ultimately selected for inclusion.

Data extraction from included studies regarding study design, patient demographics, surgical interventions, reoperation rates, complications, and clinical outcomes was independently performed by two reviewers on a predeveloped standardized form. The results were synthesized narratively, with key data presented tabularly for comparison.

The quality of the included cohort studies was evaluated using the ROBINS-I (Risk of Bias In Non-randomized Studies of Interventions) tool.⁴ Each study was reviewed and categorized into one of the following levels: low risk, moderate risk, serious risk, or critical risk of bias for each domain. Studies with low or moderate risk across most domains were considered to have acceptable quality, while those with serious or critical risk of bias were flagged for potential concerns. No studies were excluded solely based on ROBINS-I assessment, but the level of bias was considered when interpreting the overall findings (Table 1).^5–9

A qualitative synthesis was conducted to compare reoperation and complication rates and other clinical outcomes across the studies.

Case study

Using the objective pain score scale, 80% of patients showed significant improvement in pain post-surgery from 10° as presumed to be preoperatively to 6°. Only one case had a complicated foot drop following our intervention; it was a partial one preoperatively but, unfortunately, became a complete one postoperatively. Only 3 cases of postoperative infection were reported, but all were treated conservatively without reopening them. The sensory radiculopathy showed improvement in only 30% of cases; other cases required treatment with medical neuroleptic drugs. There were also improvements in the Carnovsky rating scale and the distance walked before the onset of pain (Tables 2-4).

Subjective pain score

The patient’s subjective pain scores improve significantly postoperatively. Assuming that each patient had a presurgical pain score of 10, in this series, 23.7% of patients described their pain score as 3-4, which was a significant reduction in their pain. 50% of the patients described their pain as moderate, with scores ranging from 5-6. A smaller group, 18.3%, experienced a pain score ranging from 7-8, and a further 8% reported pain scores between 9-10, indicating very little pain relief for these few patients. In general, most patients expressed that they had considerable pain relief after surgery.

Carnovsky rating scale

The Carnovsky rating scale of the functional status dramatically improved after surgery. Fifty percent of patients were at a score of 4, and 44.8% were at a score of 5 before the operation. After the follow-up period, these percentages dropped significantly to 2.6% for both scores. On the other hand, the number of patients scoring relatively higher in the scale increased: 18.4% scored 7, 23.7% scored 8, 31.7% scored 9, and 18.4% scored 10. This shift shows an improvement in the functional status of patients following the new approach in management.

Walking distance before the onset of pain

The walking distance before the onset of pain also exhibited considerable improvement postoperatively. Whereas 36.8% of patients could walk only up to 15 minutes and 52.6% from 15-30 minutes without pain before surgery, these numbers decreased in the post-surgery phase to 5.2% and 10.5%, respectively. More encouragingly, unlike in the preoperative phase, 47.3% of the patients were able to walk for 45-60 minutes, with 29% able to walk for over an hour without pain, which pointed out that these patients significantly improved their mobility and endurance.

Findings from the study conclude that the new management strategy in place of conventional decompression laminectomies, foraminotomies, is proven to help patients with lumbar spinal canal stenosis significantly improve pain relief, functional status, and mobility. Figures 2 and 3 demonstrate the size of the thecal at the lumbar level and the impact of any compressive masses on the related anatomical structures. The results obtained here present a promising alternative treatment to the unsuccessful decompression surgery of the primary treatment. This may further be held out to prove foraminotomies as effective in reducing pain and improving functional outcomes in previous laminectomy patients who showed recurrent symptoms. Such targeted relief could afford lasting alleviation to patients with spinal canal stenosis, enhancing quality of life since it brings in significant improvement in terms of reduction of pain scores and functional assessments.

Figure 2. The thecal size in the lumbar area at the level of the pedicle is usually wide enough so that the nerve roots can float freely in it.

It has a potential space to accommodate any pressure by mass lesion, almost 75% of its diameter before compression on the nerve roots occur. Prepared by Dr. Mohammed A. Bani Saad.

Figure 3. A - Any mass lesion pressing on the thecal sac will let the nerve root swim away from it. This provided by the ample potential space of the thecal sac. B - Any pressure on the exit foramen will compromise the nerve root because the dural sleeve (arrow) attached to it will prevent it from flooding away from the compressed lesion. Prepared by Dr. Mohammed A. Bani Saad.

Systematic review

This review synthesized data from five key studies examining reoperation rates following spinal decompression with or without fusion in patients with lumbar spinal stenosis. The results demonstrate varying outcomes in terms of reoperation rates, complications, and patient-reported outcomes, depending on the type of surgical intervention and patient characteristics (Table 5).^5–9

Reoperation rates

Reoperation rates varied significantly between patients who underwent decompression alone and those who underwent decompression with fusion. Fusion generally reduced reoperation rates at the index level but increased the likelihood of reoperations at adjacent segments due to adjacent segment disease (ASD). For instance, fusion often resulted in more stability at the treated level, particularly in cases with degenerative spondylolisthesis (DS), leading to fewer reoperations at that level. However, the increased mechanical stress on adjacent spinal segments due to fusion frequently led to degeneration over time, with reoperation rates at adjacent levels being notably higher in fusion patients. One study⁸ reported rates of adjacent segment reoperation as high as 9.7% for fusion compared to 4.2% for decompression alone. On the other hand, higher reoperation rates at the index level were noted for decompression alone, particularly in those procedures where instability was left unidentified. Rates for reoperation after a decompression alone were recorded to range from 4.0% to 6.2%,^8,9 with recurrent symptoms and incomplete decompression being the more common reasons that necessitate further surgical interventions. Without fusion, the spine may remain vulnerable to degeneration at the treated level, which often necessitated additional surgeries.³

Complications and risk factors

It was expected that the type of surgery further modulated the rate and nature of complications. Fusion patients had a higher risk for pseudarthrosis, which is characterized by the failure of bone fusion, PJK, and implant failure.⁹ One of the most common reasons for reoperation following fusion surgeries was PJK, or abnormal curvature that developed above a fusion; this occurred in as many as 40% of various cohorts’ reoperations.⁹ The use of multiple levels of the spine during a fusion greatly increased the likelihood of its complication. In fact, multilevel surgery was a significant risk factor for subsequent reoperations.⁹ In contrast, decompression often created a need for reoperations due to problems such as recurrent stenosis or incomplete decompression.⁹ Recurrent stenosis occurred up to 48.8% in one study, and further intervention was needed to relieve the symptoms.⁹ Further, another significant cause for additional surgeries was the instability in the patients who first underwent decompression alone.⁷ The need for consideration of the choice of operation according to the patient’s condition is thus pointed out, especially in those cases when spinal instability can be an issue.

Comorbidities such as diabetes and cardiovascular diseases further increased the odds for reoperations, especially in cases of fusion patients.⁹ Deyo et al. (2011)⁶ stated that an older patient with additional health conditions presents more complications. These complications, along with implant-related failures, contribute a lot to the risk of reoperation.

Clinical outcomes and patient-reported measures

Patient-reported outcomes significantly improved for both groups, but fusion tended to be somewhat better regarding pain relief and patient satisfaction. Generally speaking, the patients who underwent fusion reported more significant improvements in back pain, which may be explained by the stabilizing effect of the surgery. In the series by Kim et al. (2020),⁹ medially, improvement in back pain was significantly better, with a mean improvement score of 3.9 ± 1.7 compared with a mean of 2.5 ± 1.5 for decompression alone. Fusion patients also reported higher satisfaction rates: 85.5% for fusion patients vs 72.3% for decompression patients.

Despite these enhancements, fusion had a higher rate of complications, which included pseudarthrosis and failures of the instrumentations, that might diminish the patient’s satisfaction when reoperation is required.³ However, for complication-free patients, fusion offered more durable relief from mechanical back pain than decompression alone.

Decompression-only surgeries also showed significant gains, particularly in alleviating the leg pain of neurogenic claudication. While the relief from back pain was generally not as robust as that seen with fusion, the decompression did involve improvement of mobility and reduction of leg pain without the additional risks associated with fusion. However, patients with untreated instability or more advanced degeneration of the spine typically required additional interventions due to the inability of decompression to prevent disease progression in those circumstances.⁷

With regard to reoperations, it is usually the case where ASD causes patients who underwent fusion to do reoperations at an adjacent level. Such reoperations did not usually worsen clinical outcomes. In a number of cases, even the reoperation following fusion still yielded a comparable or even better outcome in terms of pain relief and quality of life.⁸ This suggests that, while fusion may increase the need for further surgery at adjacent levels, the long-term benefits, particularly for back pain, remain favorable for many patients.

Timing of reoperations

The timing of reoperations also varied between the two groups. While reoperations subsequent to decompression alone generally occurred much sooner, with many patients requiring revision surgery within the first year post-operatively due to incomplete decompression or recurrent stenosis,⁹ reoperations after fusion tended to be somewhat later, often several years following the initial surgery, when ASD developed in a progressive way at adjacent levels.⁸ This is partly due to the fact that degenerative changes in adjacent segments following fusion tend to take longer, compared to the quicker recurrence of symptoms observed following decompression alone.

Potential for hybrid approaches, future research

One direction that would be very important to take in future studies is the investigation of hybrid surgical approaches that incorporate the elements of both decompression and stabilization without the rigidity of traditional fusion. Dynamic stabilization has the potential, for example, to stabilize the spine without the same magnitude of biomechanical stress on adjacent segments, with a potentially decreased risk of ASD. Minimally invasive techniques in performing fusion surgery may further reduce complications such as PJK and implant failure.⁹ It will permit more precise, targeted interventions that preserve more of the motion of the spine.

Future studies also need to target subgroups of patients who are most likely to benefit from each surgical variant. Factors related to age, comorbidities, and spinal anatomy can be used better in outcome prediction and intervention tailoring. For example, patients with isolated stenosis who have no evidence of instability may fare well with decompression alone, while patients with multilevel degenerative or spondylolisthesis disease may reap greater benefits from fusion. Moreover, predictive models might have a significant impact on enabling surgeons to better assess the risk of ASD and reoperation following fusion and thus enable more personalized treatment strategies.