This study demonstrated significant improvement in postoperative VAS and ODI scores compared to preoperative scores in patients who underwent either decompression alone or further pedicle screw fixation, with no significant difference between both groups. Furthermore, improvement in muscle power, urinary dysfunction, and patient’s satisfaction were comparable in both groups.
The mean age of the studied patients at the time of surgery was 40.1 ± 10.0 years. It was previously reported that upper lumbar disc herniations are characterized by being more prevalent among older patients compared to the lower lumbar disc levels [11, 13].
The upper lumbar disc herniations in this work were distributed as ten (21.7%) patients with T12-L1 level, 16 (34.8%) at L1-L2 level, and 20 (43.5%) at L2-L3 level. Similarly, ElKatany et al. [11] reported higher L2-3 incidence (60%) compared to lower (40%) incidence of L1-2 disc prolapse in their series of upper lumbar disc herniations. In order to reduce motion and stress at the upper lumbar spine, the incidence of disc herniation is much less lower compared to lower lumbar levels as reported by Jha et al. [14].
The neurological manifestations of upper lumbar disc herniations included ill-defined radiculopathies that cannot be clearly categorized into typical muscle group weakness, dermatomal sensory deficits, or reflex deficits. These radiculopathies may be associated with a narrower upper lumbar spinal canal compared to that of the lower spinal canal. So, more than one root could be compromised by a single disc herniation [5].
In this study, patients were presented with back and lower limb pain, and the median preoperative VAS scores were 8.0 and 7.0 in both groups respectively. This coincides with Elqazaz [15] who reported that most patients with ULDH presented with back and buttock pain in addition to leg pain distributions, with the mean values of preoperative back pain by VAS were 7.7 ± 0.3. However, it has been stated that localized pain of the back and lower limbs is rarely demonstrated in ULDH, and it usually precedes the development of myelopathy [16]. Symptomatic herniations present as ill-defined lumbar radiculopathy from both mechanical compression and chemical irritation of the nerve roots [17]. Moreover, it has been reported that pain and/or numbness confined to the thigh area proximal to the knee joint is a characteristic sign of L2 nerve root disturbance, whereas pain distribution along the medial aspect of the knee joint is highly suggestive of L3 nerve root compression [18].
In the current study, about one-third of the patients showed muscle weakness and sphincteric disturbance. Upper lumbar disc herniations are known to be associated with a higher risk of deferent degree of compression upon the conus medullaris leading sometimes to cauda equina syndrome. Bladder dysfunction and muscular weakness of the legs are among its manifestations [19]. Our finding is in agreement with Toubar and El Sawy [20] who reported cauda equina syndrome in 30% of Egyptian patients with ULDH at their initial presentation.
Diagnosis of ULDH in this study was based on clinical manifestations followed by radiologic investigations including MRI of the lumbar spine. One of the specific clinical tests used in diagnosis was the positive femoral stretch test. It is known as a relatively good diagnostic method in about 84 to 94% of ULDH. The stretching of the femoral nerve triggers pain because L2, L3, or L4 spinal nerve roots consider the main components of the femoral nerve [21].
Surgical intervention for ULDH should be taken into consideration in cases with refractory complaints [22]. On the other hand, surgical intervention is mandatory and considered as an emergency in case of cauda equina symptoms [23]. According to Satoskar et al. [24], the upper lumbar spine has unique anatomic landmarks that present surgical challenges. Furthermore, there are a variety of techniques besides the conventional laminectomy done for upper LDH [7]. Therefore, the choice of the surgical approach is an important issue while managing patients with upper lumbar herniations, because proper preoperative surgical planning can play the most important role to get a favorable surgical outcome and avoid complications [22].
Many factors play a role in determining the choice of surgical approach. These include disc size, location, extent of calcification, surgeon’s experience, degree of spinal cord deformation, and the general medical record of the patient. In cases of L1-L2 and L2-L3 disc herniations, radiologic findings are the outmost important criteria for the selection of the surgical approach [25].
Among the surgical approaches for lumbar disc herniation, open lumbar discectomy (OLD) is considered the gold standard [26]. This technique is much commonly performed because of its good clinical results. In such technique, there is excision of some posterior structures such as lamina, ligament flavum, and facet joints [27]. Thus, it could possibly lead to lumbar instability and iatrogenic injury [28]. Addition of spinal stabilization and fusion by a multitude of instrumentations has been developed [29]. Transpedicular screw fixation has been the treatment of choice for stabilizing segmental instability especially in cases that require wide decompression [30].
In this study, 22 patients (group 1) underwent open discectomy via laminectomy and partial medial facetectomy, and 24 patients (group 2) were operated upon via the previous maneuver plus transpedicular screw fixation to show any differences in surgical outcomes.
There were no significant differences between both groups as regards pain improvement measured by VAS score. Both groups showed significant reduction immediately following surgery and at each of 7 days, 3 months, and 6 months in comparison with the preoperative VAS score (p< 0.001). Furthermore, both groups showed good regaining of functional ability; they had significant stepwise reductions in the median ODI scores at the 3rd and the 6th months following surgery compared to the preoperative ODI score with no significant differences between both groups. Subjective evaluation of patient’s satisfaction was comparable in group 1 (90.9%) and group 2 (87.5%). Compared to these findings, Lin et al. [31] have recently reported a greater satisfactory rate (93.8%) in series of 16 patients who were operated via transpedicular pedicle screws and interbody fusion with a cage compared to decompression alone (66.7%). Follow-up of their patients also revealed better functional outcomes (ODI score) at 3 months in the fusion group compared to the decompression group. The addition of interbody fusion with a cage to transpedicular pedicle screw fixation might explain the reported better functional outcomes. However, Lin et al. [31] agree with our findings in the presence of non-significant differences between fusion and decompression groups as regards VAS score, improvement of muscle power, and bladder dysfunction.
An earlier case series of nine patients surgically treated for upper LDH via discectomy through an anterior approach was reported. Four patients of them underwent additional spinal instrumentation using the Kaneda device and Z-plate system. All patients showed improvement of all clinical manifestations [32].
It seems that addition of pedicle screw fixation did not improve the outcomes of ULDH patients. Moreover, our findings revealed significantly lower mean time of the operation and the mean amount of blood loss in patients who underwent decompression alone. The choice of screw fixation is important if a wide posterior laminectomy is performed to decompress the neural structures; this may lead to disruption of the normal anatomy and mechanics of the spinal column resulting in instability, which can lead to surgical failure. In such cases, spinal fusion guards against the possible instability and adds immediate immobilization of the spinal segment, which can improve the axial pain as well as radiculopathy [7, 33]. However, the higher incidence of adjacent segment degeneration, higher costs, and higher complication rates should be taken into consideration [34].
All patients in this study showed significant improvement of postoperative pain, function, muscle power, and urinary incontinence compared to the preoperative conditions. These favorable outcomes of ULDH are in agreement with Sanderson et al. [9] who showed improvements of preoperative pain following microdiscectomies of L1-L2 and L2-L3 disc herniations in 60% of patients. Similarly, Kim et al. [5] detected relieve of preoperative manifestations in 80% of cases of ULDH operated via decompression surgery by conventional laminectomy or a posterior transdural approach. Furthermore, transfacet discectomy with pedicle screw fixation in twenty patients diagnosed with herniated disc at upper levels (T12-L1, L1-L2, and L2-L3) showed significant improvement in radicular and back pain, myelopathy, and statistically significant improvement of ODI score following surgery [7].
Our study reported a non-significant association between patient’s sex and level of the lumbar disc and surgical outcomes; this was in agreement with Pochon et al. [35].
The retrospective design and the small patient numbers in both groups are considered limitations of this study. Yet, the very low incidence of ULDH is an important factor that limits recruitment of a relatively large number of patients. Furthermore, a longer follow-up is necessary to evaluate any potential complications.
