Evaluating the outcome of classic laminectomy surgery alone versus laminectomy with fixation surgery in patients with lumbar canal stenosis regarding improvement of pain and function

Management of lumbar canal stenosis should be started with conservative treatment and preferably with a multimodal approach, but in cases of severe pain with extensive neurogenic claudication symptoms, surgical intervention is indicated. This retrospective study targets to evaluate the outcome of classic laminectomy surgery alone versus laminectomy with fixation surgery in patients with lumbar canal stenosis regarding improvement of pain and function. Data of 184 patients of the study groups were divided into group A (data from patients who underwent laminectomy and foraminotomy only) and group B (data from patients who underwent laminectomy and foraminotomy with spinal fixation). Preoperative, operative, postoperative (PO), and follow-up data were extracted and analyzed from files of patients fulfilling the inclusion criteria. Primary outcome was at least 50% improvement of pain severity regarding numeric rating scale (NRS) and Oswestry disability index (ODI) score at 6-months PO compared to preoperative scores. Operative time was significantly longer in group B than group A. Immediate PO data regarding PO analgesic requirement, amount of wound drainage, and PO hospital stay showed non-significant difference between both groups. There was a statically significant improvement of EHL muscle strength regarding Odom’s scoring in group B in which the success rate for pain improvement was 81.8% and for disability was 66.8%. There were insignificant differences in patient’s satisfaction to surgery with variable ages, a significant outcome in females and in patients with fewer levels of affection of both groups. The present study reported the efficacy and safety of the laminectomy, foraminotomy, discectomy, and medial facetectomy with spinal fixation using trans-pedicular screws for management of patients with spinal canal stenosis.


Introduction
The most frequent causes of degenerative constrictions of the spinal canal are disk herniation and spinal canal stenosis (CS) [1]. CS is a condition where the neural structures are compressed in the narrowed spinal canal and often situated only within a single specific region of the spine, most frequently in the lumbar spine [2]. Degenerative disk bulging and facet overgrowth lead to lumbar lateral recess stenosis, which is a very common cause for lumbar radiculopathy in the elderly [3].
Spinal canal stenosis presents in a variety of forms; symptomatic lumbar canal stenosis (LCS) occurs in about 10% of population and cervical CS in 9% of subjects aged over 70 years [4]. With progress of health services, the patients' longevity expectations are increasing, so number of patients with LCS is steadily increasing [5].
Basically, management of LCS should be started with conservative treatment and preferably with a multimodal approach (medical treatment, bed rest, and physiotherapy), but in cases of severe pain with extensive neurogenic claudication symptoms, surgical interference is indicated [5]. Lumbar decompression surgery is a commonly used treatment for degenerative LCS [6]. Classic surgical treatment of LCS involves wide laminectomy, foraminotomy, discectomy, and medial facetectomy if needed [7]. However, decompression surgery can further destabilize a pathological motion segment [3], and some patients develop symptomatic spinal instability [6]. Spinal instability after simple decompression promoted the development of fusion technique [8].

Objectives
The present study aims to evaluate the outcome of classic laminectomy surgery alone versus laminectomy with fixation surgery in patients with lumbar canal stenosis regarding improvement of pain and function.

Patients and methods
Data of all patients with chronic refractory pain to conservative treatment for 6 weeks and who underwent surgical interference were collected at the Neurosurgery Department, Faculty of Medicine, Menofia University at the period from June 2016 to July 2018 and were followed-up throughout a period of 6 months. The present study includes data of patients with evident manifestations of LCS as sever claudicating pain, recurrent lumbar pain that was not relieved by conservative treatment.
Data of patients with infrequent pain, mild pain relieved spontaneously or by rest, peripheral neuropathy, diabetes mellitus, cardiac, hepatic or renal diseases, coagulopathy, and all cases of spinal instability were excluded from this study.
The present study involved patients' demographic and clinical data, full medical history concerning type, site, and radiation of pain, and precipitating and relieving factors, drug history by using a 0 to 4 points Likert scale with 0, no medication; 1, simple analgesics as oral nonsteroidal anti-inflammatory drugs (NAISD); 2, injectable NAISD analgesia; 3, as needed opioid prescription medications; 4, scheduled opioid prescription medications were also evaluated at 3 and 6 months post-operative and considered one of the secondary outcome evaluation parameters.
Data of clinical examinations includes the following: -Pain severity assessment of back and lower limb by using an 11-point numeric rating scale (NRS) with numbers from 0 to 10 where 0 indicates no pain and 10 indicates worst pain imaginable [9,10]. -Assessment of disability secondary to pain by using the low back pain Oswestry disability index (ODI) that determines disability as minimal (0-20), moderate , severe (40-60), and ODI of 60-80 indicated that patient is crippled and 80-100 indicates that the patient is either bed-bound or exaggerating his or her symptoms [11][12][13]. Pain severity and ODI scores were assessed at 3 and 6 months post-operative and serves as primary outcome evaluation parameters.
-Assessment of the strength of EHL (extensor halucies longus) and feet dorsiflexor muscles at 3 and 6 months post-operative and considered one of the secondary outcome evaluation parameters by using the Oxford scale and was evaluated at 3 and 6 months postoperative and considered one of the secondary outcome evaluation parameters, with 5-strong, 4-partial resistance, 3-complete movement, 2-partial movement, 1-contraction, and 0-paralyzed [14,15].
-Assessment of improvement was assessed by using Odom's criteria at 3 and 6 months post-operative and considered one of the secondary outcome evaluation parameters that included 4 grades: excellent-relief of all preoperative symptoms and all abnormal findings were improved; good-minimal persistence of preoperative symptoms and all abnormal findings were either unchanged or improved; fair-definite relief of some preoperative symptoms, while other symptoms were either unchanged or slightly improved; poor-all preoperative symptoms and signs were unchanged or exacerbated [16].
Patients' satisfaction with the procedure was assessed with a 4-point questionnaire, ranging from 4 points (very satisfied) to 1 point (very dissatisfied) at 3 and 6 months post-operative and considered one of the secondary outcome evaluation parameters. Finally, data of radiological workup including X-ray imaging in anteroposterior (AP), lateral views and dynamic views (flexion-extension-oblique), and computerized tomography (CT) lumbosacral spine then, magnetic resonance imaging (MRI) for lumbar spine also were obtained (Figs. 1, 2, 3, and 4).
Files of patients undertook wide laminectomy, foraminotomy, discectomy, and medial facetectomy without spinal fixation as a single therapeutic procedure were categorized as group A, while files of patients undertook wide laminectomy, foraminotomy, discectomy and medial facetectomy, and spinal fixation using transpedicular screws were categorized as group B. Both groups were equal in number.

Statistical analysis
The data collected were tabulated and analyzed by SPSS (statistical package for the social science software) statistical package version 23, 2015 on IBM compatible computer for Windows statistical package and were presented as mean ± SD, numbers, and percentages by using one-way ANOVA test, Student t test and chisquare test (X2 test). P value < 0.05 was considered statistically significant.

Results
The study included files of 215 patients; 31 files were excluded for not fulfilling the inclusion criteria and 184 files were divided into two equal groups to be analyzed.  There were significant differences between the two groups regarding age and insignificant differences regarding sex and level, and insignificant differences in patient's satisfaction to surgery with variable ages, a significant outcome in females compared to males who are heavy workers and due to their early return to activity with male-female ratio 5/4, and significant differences in patients with fewer levels of affection of both groups (Tables 1, 2). All surgical procedures were completed uneventfully, and despite the non-significant difference between both groups regarding operative time for discectomy and facetectomy; spinal fixation performed for patients of group B required additional theater time, so total theater time was significantly longer in for patients of group B than those of group A. Amount of blood loss showed non-significant difference between patients of both groups and no patient required blood transfusion. All patients were transferred to the post-anesthetic care unit (PACU) for immediate PO postoperative care and when patients had stable hemodynamics were transferred to the ward of the neurosurgery department (Table 3).
At ward, time till 1st request for analgesia, number of requests and total dose consumed showed nonsignificant difference between patients of both groups. Also, amount of wound drainage showed a nonsignificant difference between both groups. All patients were home-discharged after a median duration of PO hospital stay of 3 days, and mean duration of hospital stay showed non-significant difference between patients of both groups (Table 4).
There was a significant statically sustained continuous improvement of pain and disability scores throughout the period of follow-up (at 3 and 6 months postoperation) with more improvement at 6 months postsurgery (Figs. 5, 6). These findings were more superior in patients who went to spinal fixation surgery as manifested by the significantly lower pain and ODI scores,  This table shows the non-significant difference between both groups regarding operative time for discectomy and facetectomy, the total theater time was significantly longer in patients of group B than those of group A. There was a non-significant difference between patients of both groups regarding the amount of blood loss and no patient required blood transfusion throughout the period of follow-up of patients of group B compared to that of patients of group A. There were a significant statically higher success rate in group B versus group A regarding the reduction of pain and ODI scores ( Table 5, Fig. 7). There was a significant statically lower score for PO analgesic medications, in patients of group B than those of group A. Functionally, objective testing of all studied patients showed significant improvement regarding EHL muscle strength testing in comparison to their preoperative data with significantly superior outcome among patients of group B compared to group A. As regards patients' evaluation of improvement according to Odom's criteria, 50 patients (27.2%) found the improvement was excellent, 98 patients (53.3%) found it good, 24 patients (13%) found the improvement was fair, and 12 patients (6.5%) found it poor with a significantly higher frequency of patients who found improvement was good-to-excellent in group B versus group A. Concerning patients' satisfaction, 108 patients (58.7%) were very satisfied by the outcome, 64 patients (34.8%) were satisfied and only 12 patients (6.5%) were dissatisfied, also, with a significant difference between patients of both groups in favor of group B (Table 6).

Discussion
The present study aims to evaluate the outcome of classic laminectomy surgery alone versus laminectomy with fixation surgery in patients with lumbar canal stenosis regarding the improvement of pain and function.
The present study reported more than 50% improvement of pain and disability regarding NRS pain and ODI scores throughout the period of follow-up compared to preoperative scores in both groups with This table shows a non-significant difference between patients of both groups regarding the number of requests; total dose consumed and amount of wound drainage and non-significant difference regarding the mean duration of hospital stay between patients of both groups more improvement of the second group (group B). This comes in agreement with Wang et al. [17] and Liao et al. [18] and their colleague as they used laminectomy and interlaminar lumbar-instrumented fusion for lumbar spinal stenosis and reported a significant improvement of pain and disability regarding VAS and ODI scores throughout the period of follow-up compared to preoperative scores. The present study reported the significantly high success rate regarding patients satisfaction as 58.7% of patients were very satisfied by the outcome, 34.8% were satisfied, and only 6.5% of patients were dissatisfied, with a higher success rate for patients of group B compared to those of group A. This is corresponding to Liao et al. [18] and his colleague as they retrospectively studied 181 patients who underwent posterior decompression and instrumentation with posterolateral fusion for degenerative lumbar diseases with spinal stenosis and reported 86% of patients exhibited good or excellent result.
Sun et al. [19] also reported the satisfactory clinical and radiological outcomes with the use of multisegmental transforaminal enlarged decompression plus lumbar fusion for the treatment of multilevel lumbar spinal canal stenosis and found that this technique can reduce surgically induced instability.
Our results reported that the effectiveness of procedure including fixation using transpedicular screws with posterior decompression was also manifested as significantly higher improvement of muscle power of dorsiflexors and extensor halucies longus muscles regarding Odom's scoring with  more improvement of group B and the significant reduction of the use of pain medications with subsequent higher satisfaction rates throughout the period of follow-up compared to preoperative parameters. This comes in agreement with Zeng et al. [20] and his colleague as they found that unilateral pedicle screw fixation combined with contralateral percutaneous translaminar facet screw fixation and lumbar interbody fusion is a good choice for the treatment of spinal canal stenosis regarding improvement of muscle power and the reduction of the use of analgesics.
The applied procedures for both groups were safe with acceptable operative time, blood loss, and short postoperative hospital stay with non-significant differences  between both groups. In line with safety of the applied procedures, Munting et al. [21] compared patient outcomes and complication rates after different decompression techniques or instrumented fusion in lumbar spinal stenosis and found laminectomy with instrumented fusion was significantly more beneficial than laminotomy, hemilaminectomy, and laminectomy regarding leg pain improvement with non-significant differences regarding operative and short-term postoperative data.

Conclusion
The present study concluded the efficacy and safety of the applied procedure including wide laminectomy, foraminotomy, discectomy, and medial facetectomy with spinal fixation using transpedicular screws for management of patients with spinal canal stenosis. However, a multicenter comparative study with long-term follow-up is recommended to establish the obtained results.