Good outcomes have been demonstrated using microscope-assisted laminar fenestration decompression for the treatment of LSS, and endoscopic surgery is growing in favor among spine surgeons and patients with LSS as technology and treatment approaches evolve [19,20,21].
Results showed that both postoperative VAS-LBP and VAS-LP scores were considerably diminished after surgery compared to pre-operative levels; This performance was in keeping with evidence from the prior literatures, and the ODI score further declined considerably throughout follow-up, as had been previously documented [22,23,24]. Although microscopically fenestration of the lamina is effective and minimally invasive, traditional surgical methods still require the use of a retractor to pull the soft tissue and separate the paravertebral muscles, which is still invasive to the patient and may result in iatrogenic spinal instability. However, low back pain is usually residual after these complications have occurred [18, 20, 23]. In comparison to the microscope-assisted lamina fenestration decompression technique, the Delta large channel technique has the benefits of a smaller surgical incision (< 10 mm) and the working channel. The tubular channel is utilized for orderly tissue dilation, allowing for precise access to the surgical area for surgery, preservation of the entire posterior paravertebral muscle tissue, and minimalization of bone trauma . In this study, the VAS-LBP score 1 week after surgery in the FE group was lower than that in the microscopical group (2.80 ± 0.92 vs 3.40 ± 0.50, P < 0.05). This difference may be attributable to the length of surgical incision and surgical method in the microscopical group. Paravertebral muscles and surrounding soft tissues are wounded as a consequence of the device’s dislocation, pulling and stretching of local tissues. Early functional exercise is better facilitated by FE microscopy, which can also help patients with early low back pain. However, the two groups did not vary significantly in terms of the pain reduction they experienced from lumbago and lower limb pain (P > 0.05).
It is currently reported that most studies reporting the postoperative clinical effects of LSS are focused on improving postoperative radiative pain, whereas few studies report improvements in postoperative numbness [25,26,27,28,29]. Typically, patients experience significant pain relief after lumbar decompression surgery, but the sensation of numbness does not improve as much as they might expect. As evaluating subjective symptoms of numbness is challenging, in this study we attempted to quantify the degree of numbness in the lower limb using NRS, allowing patients to self-report their level of discomfort. In this study, lower limb numbness and pain scores were significantly reduced 3 months after surgery, but there were no significant changes during follow-up. The NRS score of 2 groups was significantly lower than that of control group (P < 0.05), but there was no statistical significance (P > 0.05). Consequently, both surgical procedures are capable of reducing lower limb numbness in patients to a similar extent. Compared with preoperative, the proportion of patients with residual postoperative lower limb numbness (NRS > 1) was more than that of lower limb pain (VAS > 1) and disability (68.47% vs 56.76%). There was more likelihood of persisting numbness after surgery than pain, according to our results. It is important to note that despite the reduction in lower extremity NRS scores following surgery, patients may still retain the perception that LSS symptoms have not improved because of the persistence of numbness, thereby reducing their satisfaction with the treatment. Studies have previously indicated that the initial postoperative improvement of lower limb numbness symptoms is the most evident, followed by a gradual decrease. This study’s findings are consistent with those of others that found it difficult to instantly [30, 31] alleviate the numbness that often followed lumbar surgery. The lower limb numbness score decreased significantly 3 months after surgery, but there was no significant change after surgery. Regarding this, we speculated that the rapid recovery of lower limb numbness in patients at some time after surgery might be related to the rescue of reversible nerve injury. A significant change in the NRS from 3 months to follow-up was observed in the residual numbness, however, which is primarily caused by reversible nerve damage. There is also the possibility that the numbness in the lower extremities may be due to a torn dural. In this study, FE found 3 cases of dural tears (1 of which developed hypertension after dural rupture and forced the termination of surgery; During the microscopically controlled group, one patient remained in bed for seven days postoperatively, and antibiotics were given in order to prevent intracranial infection and surgical incision. The following are the primary considerations behind our study of dural tears in the EF group:1. Surgical technique selection requires further research. There was one patient with L2/3 stenosis, and we chose to use the Delta channel technique for treatment. 2. Inadequate hemostasis under the microscope, leading to damage due to bleeding in the surgical field; 3. A patient experienced significant adhesion owing to conservative epidural steroid injection, which led to an inadvertent tear during dissection because of inadequate preoperative preparation. However, different from previous literature reports [32,33,34,35], residual numbness and decreased muscle strength were found in only 1 out of 4 patients with sac tear during postoperative follow-up. We speculate that this may have something to do with the low number of cases.
The FE group had a longer average surgical time (92 minutes) than the Micro group (75 minutes) and, like most spinal endoscopic procedures, had a higher learning curve [36, 37]. This may be due to the fact that endoscopic surgery has a limited field of vision and operating region, and that there are discrepancies between the real operation and the light field, both of which might pose difficulties for the surgeon. Because hemostasis is already challenging under endoscopy, any failure to achieve full clotting will have a significant impact on the surgical process and make the patient more uncomfortable. A dural sac tear might potentially result from an inadequate surgical field. The patient in this study had a dural tear, which was predominantly caused by the worsening of the surgical area owing to hemorrhage, which presented some challenges to the physician while exposing the nerve roots. Regarding endoscopic hemostasis, studies [38,39,40] have pointed out that, compared with hemostasis by pressure of high water pressure, it is better to adjust patients’ blood pressure, because high water pressure will make the operative field become chaotic, and may also cause patients’ intracranial pressure height. Contrary to what may be expected, the operational field remained calm and the hemostatic effect remained effective despite the high pressure water being applied for just a little time. There was 1 patient with increased intracranial pressure after surgery, which was due to the increased blood pressure caused by the tear of the posterior dural sac, while the other patients did not have the above situation. Therefore, we speculate that this may be related to the water flow outside the surgical area and the control time of high pressure water compression. All patients were treated with high-pressure water to stop bleeding for no more than 30 seconds. Meanwhile, the anesthesiologist was asked to reduce the blood pressure to systolic pressure (120-100) mmHg and diastolic pressure (90-70) mmHg for hemostasis.
Although the operative time of FE group was significantly prolonged, the operative time was progressively shortened with the improvement of the operator’s proficiency, and the clinical effect was good without major surgical complications.
This study has several limitations. First, a modest number of instances were collected for this study sample. Secondly, the follow-up indexes changed greatly ranging from 1 week to 3 months demonstrated substantial variation. The outcomes of the experiments may have been different if more thorough follow-up had been conducted. We believe that the inaccuracy of findings can be mitigated if the follow-up time is more comprehensive. Third, statistical indications such C-reactive protein, creatine phosphokinase, etc. are inadequate when only lumbar pain VAS score, operation time, intraoperative blood loss are employed to evaluate surgical trauma during it weakens the evaluation’s scientific rigour by decreasing the number of quantitative indicators used. Fourth, for numbness symptoms, we attempted to utilize NRS for quantification, but “numbness” involved multiple symptoms, such as numbness, hypoesthesia, paresthesia and sensory disturbance, etc., the use of an 11-point numerical rating scale (NRS) for quantification was too general to refine the above symptoms; similarly, the NRS score could only indicate the intensity of numbness and was incapable of assessing the area. Lower limb numbness improvement can be overestimated when measured by NRS due to a particular bias compounded by the fact that patients’ numbness areas may diminish without a corresponding increase in numbness intensity. Fifth, this study’s follow-up time is brief to draw any conclusions about the treatment’s long-term efficacy.