In recent years, with the improvement of people's living standards and the change in diet structure, the incidence of obesity in our country has increased markedly. Obesity has been implicated as a risk factor for LDH.11,12 Traditional open surgical treatments in obese patients use a large incision to allow adequate visualization at depth, which may result in greater injury of muscle and soft tissue, as well as increased bleeding and infection risks.13,14 Many spinal surgeons have used the technique of PTED to treat obese patients with LDH in recent years. They suggest that PTED is a safe and generally effective minimally invasive technique for obese LDH patients.15,16 However, LDH is a rare cause of morbidity in obese adolescent patients. To our knowledge, there has been no study of the application of the PTED technique for treating obese ALDH patients. Meanwhile, an increasing number of studies have suggested that PTED is a safe and efficient alternative to open discectomy and microdiscectomy for the treatment of adolescent lumbar disc herniation.17,18 Therefore, the current study focused on investigating the efficiency of PTED in the treatment of obese adolescent patients with LDH.
OT is usually one of the most concerning problems for patients. Chen et al19 reported that the mean duration of surgery was 97.2 min and the mean length of HS was 8.1 days in adult LDH patients with PTED. A recent meta-analysis comparing the transforaminal approach and interlaminar approach suggested that the average OT was 61.9–97.5 min and the average HS was 3.2–4.9 days in the PTED group.20 Chen et al21 reported that the average OT in the adolescent LDH group was 110 min longer than the 95 min reported in the adult group (P = 0.41). However, the surgical approaches included the transforaminal approach and interlaminar approach in both groups.21 Bae et al22 reported that obese and normal patients spent a mean of 55 min and 51.8 min, respectively, in surgery. Meanwhile, the mean length of HS of obese and normal patients was 2.8 days and 3.3 days, respectively.22 In our study, we found that the average OT in the obese adolescent group was 101 min, which was significantly longer than the 84.7 min in the normal group (P < 0.001), and the average HS (3.3 vs 3.1; P = 0.070) was similar in the obese and normal groups. We observed different outcomes in each study. However, obese patients spent more time in surgery, which was a consistent result. We also considered the differences between these studies mainly based on the following points: First, the subjects in each study had different conditions. Patients with a more difficult surgery require a longer OT. Second, the PTED procedure has a steep learning curve, requiring a different set of cognitive, psychomotor and technical skills. Surgeons have different experiences, and repetition might lead to different clinical effects. Third, during the PTED procedure, it is more difficult to puncture and create the passage in obese patients than in normal patients because of the thick soft tissue layer in the former. Moreover, we believe that careful preoperative evaluation and good intraoperative fluoroscopy are very important for obtaining satisfactory surgical results in obese patients.
Many studies have encouraged patients to get out of bed early after PELD to recover their function and return to work early. Nie et al23 reported that the postoperative time in bed of 30 patients with L5–S1 disc herniation was 5.0 ± 1.1 hours after PTED. Another study suggested that the mean postoperative in-bed time was 32.7 hours in adult LDH patients after PTED.19 In our study, we found that the average TTA (29.9 vs. 25.0 days; P < 0.001) was longer in the obese group than in the normal group. Considering the healing time of soft tissues such as the annulus fibrosus, our team recommends that patients stay in bed for at least 3 weeks after PELD. Of course, when eating or urinating, the patient can wear a waist brace and get out of bed. During other periods of time, patients mainly performed rehabilitation exercise in bed. Rehabilitation exercises mainly focused on low back muscle exercises and limb strength exercises performed in bed. Qin et al24 reported that the time to first ambulation after PELD was one of the crucial factors affecting recurrence after PELD. These results suggest that regardless of the lumbar protection method used, early ambulation will certainly subject the disc to a load too soon after lumbar surgery.24 Therefore, in obese adolescent patients who get out of bed early after PELD, it would be easy to increase the load on the intervertebral disc, resulting in an increase in the probability of postoperative recurrence. Therefore, we do not recommend that obese adolescent patients with LDH ambulate early after PELD.
Spinal surgeons often pay attention to their own radiation exposure in spinal surgery, and thus, patient radiation exposure is less reported. In our study, we found that the X‑ray exposure times in the obese patient group (41.0 ± 5.8) were significantly increased compared with those in the normal group (31.6 ± 7.0). The organs and tissues are more sensitive to the effects of radiation in childhood or adolescence than in adulthood.25 Radiation exposure leads to a higher incidence of malignant tumors in young patients.26,27 However, the body surface markers of obese ALDH patients, especially their iliac crests, are not easy to palpate, so we increased the fluoroscopy time to make the preoperative positioning of the surgical target more accurate. We are the first to report the fluoroscopic localization of the iliac crest in obese patients so that we could select the appropriate insertion point and place the channel accurately. We believe that accurate preoperative body surface positioning is very important for obese ALDH patients with PETD because of the difficulty in intraoperative puncture and channel adjustment. Although obese ALDH patients have increased X-ray exposure, it is important to ensure safe and effective surgical outcomes. With the improvement of our experience in the treatment of PELD in obese patients, we believe we can certainly reduce the radiation exposure dose.
Many studies have reported that, compared with other surgical procedures, PETD can achieve similar surgical results with less tissue damage.28,29 Bae et al22 also found that the clinical and functional outcomes of obese patients were similar to those of normal patients who had undergone PETD for LDH. In our study, we observed that both obese and normal patients showed significant improvements in ODI scores and in back and leg pain VAS scores at 1 day post-operation. From 1 month after the operation, there was no significant difference between the 2 groups in the VAS and ODI scores. Both the obese and normal groups showed greater improvement in SF-36 score assessment at 1 year post-operation.
Our study has several potential limitations that should be pointed out. First, the number of obese cases was relatively small, and the follow-up time was short. Second, due to the anatomic differences between L4/L5 and L5/S1, there were different surgical results during the implementation of PETD. This could also have led to outcome bias. Third, there was no imaging evaluation of the patients in our study. Doubtless, a larger, longer follow-up study is needed to further validate our clinical findings.