Traditional Transforaminal Lumbar Interbody Fusion Research Articles

Surgical Strategy for Lumbar Disc Herniation based on the MSU Classification: Percutaneous Endoscopic Lumbar Discectomy versus Transforaminal Lumbar Interbody Fusion: A 5-year Retrospective Study.

Currently, there is no established guideline on whether to opt for percutaneous endoscopic lumbar discectomy (PELD) or traditional transforaminal lumbar interbody fusion (TLIF) surgery based on specific types of lumbar disc herniation (LDH). Based on the Michigan State University (MSU) classification system, this study conducted a medium- to long-term follow-up analysis of two surgical methods over 5 years for the first time, aiming to provide empirical evidence to assist in making more informed decisions before surgery for LDH treatment. This was a retrospective study that included 273 patients with single-level LDH who underwent PELD or TLIF treatment at our hospital between January 1, 2016, and December 31, 2018. Detailed metrics included preoperative and postoperative visual analogue scale (VAS) scores and Oswestry disability index (ODI) at 1-day, 1-week, 1-year, and 5-year follow-ups. Complications, recurrences, and 5-year postoperative modified MacNab criteria scores were also recorded. Statistical methods included independent sample t-tests, repeated measures analysis of variance (ANOVA), and χ2 tests. Classified into seven groups according to the MSU classification, it was found that there was an improvement in the VAS and ODI scores at four postoperative follow-ups (p < 0.001). PELD showed better results than TLIF in reducing pain and improving the ODI scores in the classifications of 3B, 2B, and 2C (p < 0.05). TLIF demonstrated consistent superiority over PELD in 2A, 2AB, 3A, and 3AB classifications (p < 0.05). The total recurrence rate in the PELD group (11.05%) within 5 years after surgery was higher (p < 0.05) than that in the TLIF group (3.96%). These were mainly concentrated in the 2A, 2AB, 3A, and 3AB types. Moreover, the rate of excellent and good outcomes in the PELD was higher than in the TLIF but no significant difference (χ2 = 1.0568, p = 0.5895). This study suggests that PELD and TLIF may relieve LDH, but have advantages under different MSU classifications. The MSU classification has specific guiding significance and could aid in the surgical selection of PELD or TLIF to achieve optimal treatment outcomes for patients with lumbar disc herniation.

Efficacy of the Dynesys Hybrid Surgery for Patients with Multi-Segmental Lumbar Spinal Stenosis.

ObjectiveThe efficacy of hybrid (Dynesys and fusion) surgery and the traditional transforaminal lumbar interbody fusion surgery was compared in patients with multi-segmental lumbar spinal stenosis.MethodsA total of 68 patients with multi-segmental lumbar spinal stenosis subjected to surgery were recruited between January 2013 and October 2020 in the First Affiliated Hospital of Southern University of Science and Technology. The patients were divided into a hybrid group (N = 33) and a TLIF group (N = 35) by surgery. After surgery, follow-up was conducted for 12 months. Between the two groups, the following parameters were compared: general conditions, clinical symptom scores, imaging parameters, and early complications.ResultsA statistically significant difference in the duration of surgery was noted between the two groups. After 12 months of follow-up, the range of motion disappeared in the TLIF group, while 63.53% was preserved in the hybrid group with statistically significant differences. A statistically significant difference was identified in the Oswestry Disability Index one week after surgery. Nonetheless, no statistically significant differences were observed at the 12-month post-surgical follow-up. Pfirrmann grade showed a 3.03% upper adjacent segment degeneration rate in the hybrid group (1/33) at 12-month follow-up and 2.86% (1/35) in the TLIF group. Notably, no early complications (screw loosening and wound infection) were identified in the two groups.ConclusionThe Dynesys hybrid surgery combined the advantages of two systems of dynamic stabilization and rigid fusion. Besides, hybrid surgery is potentially a novel approach for the treatment of multi-segmental lumbar spinal stenosis.

Three-dimensional Navigation-guided, Prone, Single-position, Lateral Lumbar Interbody Fusion Technique.

Lateral interbody fusion provides a significant biomechanical advantage over the traditional transforaminal lumbar interbody fusion due to the large implant size and optimal implant position. However, current methods for lateral interbody cage placement require either a two-staged procedure or a single lateral decubitus position that precludes surgeons from having either full access to the posterior spine for direct decompression or comfortable pedicle screw placement. Herein is one institution's experience with 10 cases of a prone single-position approach for simultaneous access to the anterior and posterior lumbar spine. This allows both lateral lumbar interbody cage placement, direct posterior decompression, and pedicle screw placement, all in one position. Three-dimensional (3D) navigation is utilized for increased precision in both approaching the lateral spine and interbody cage placement. The traditional blind psoas muscle tubular dilation was also modified. Tubular retractors and lateral vertebral body retractor pins were used to minimize the risks to the lumbar plexus.

Comparison of CLIF and TLIF in treatment of degenerative lumbar spondylolisthesis combined with lumbar spinal stenosis

To observe the difference between crenel lateral interbody fusion (CLIF) and transforaminal lumbar interbody fusion (TLIF) in the treatment of degenerative lumbar spondylolisthesis (DLS) combined with lumbar spinal stenosis (LSS). The clinical data of DLS combined with LSS patients meeting the selection criteria admitted between May 2018 and May 2019 were retrospectively analyzed. According to different surgical methods, the patients were divided into CLIF group (33 cases) and TLIF group (32 cases). There were no significant differences ( P>0.05) between the two groups in gender, age, disease duration, lesion segments, lumbar bone mineral density, degree of lumbar spondylolisthesis, and preoperative visual analogue scale (VAS) score, Oswestry disability index (ODI), intervertebral space height, intervertebral foramen height, lumbar lordosis (LL), and segmental lordosis (SL). The operation time, intraoperative blood loss, and perioperative complications were recorded and compared between the two groups. Lumbar CT scan was performed at last follow-up to compare the intervertebral fusion rate between the two groups. Intervertebral space height, intervertebral foramen height, LL, and SL were measured before operation, at 2 weeks, 3 months after operation, and at last follow-up. VAS score and ODI were used to evaluate the pain and improvement of the quality of life of the patients. There were no neurological and vascular complications in the two groups. The operation time and intraoperative blood loss in CLIF group were significantly less than those in TLIF group ( P<0.05). Patients in both groups were followed up for a median time of 18 months. All the incisions healed by first intention except 1 incision in TLIF group because of poor blood glucose control. No complications such as bedsore, falling pneumonia, and deep venous thrombosis were found in both groups. At last follow-up, the intervertebral fusion rates in CLIF and TLIF group were 90.91% (30/33) and 93.75% (30/32), respectively, showing no significant difference ( χ 2=0.185, P=0.667). The VAS score, ODI, intervertebral space height, intervertebral foramen height, LL, and SL were significantly improved in both groups at each time point after operation ( P<0.05). Except that VAS score in CLIF group was significantly lower than that in TLIF group at 2 weeks after operation ( Z=-4.303, P=0.000), there were no significant differences in VAS score and ODI between the two groups at other time points ( P>0.05). The intervertebral space height, intervertebral foramen height, LL, and SL in CLIF group were significantly higher than those in TLIF group at each time point after operation, and the differences were significant ( P<0.05). CLIF in the treatment of DLS combined with LSS can achieve the similar effectiveness with traditional TLIF, and has such advantages as minimal invasion and faster recovery.

Wiltse approach combined with contralateral transforaminal lumbar interbody fusion and conventional surgery for lumbar disc herniation:a case-control study

To compare the clinical effecty of Wiltse approach combined with contralateral transforaminal lumbar interbody fusion (TLIF) and traditional TLIF in the treatment of lumbar disc herniation and its affect on injury of multifidus muscle. From June 2014 to September 2017, 90 patients with lumbar disc herniation combined with lumbar spine instability were divided into two groups (Wiltse approach group and traditional group) depend on the procedure of operation. Wiltse approach group was treated with Wiltse approach screw placement in one side combined with contralateral TLIF. There were 50 patients in Wiltse approach group, including 36 males and 14 females, aged 45 to 72 yearswith an average of (60.4± 3.1) years. The traditional group was treated with traditional TLIF operation. There were 40 patients in the traditional group, including 25 males and 15 females, aged 45 to 74 years with an average of (62.1±3.4) years. The operative time, intraoperative blood loss, accuracy of screw implantation, postoperative drainage volume and drainage tube removal time were recorded in two groups. Visual analogue scale (VAS) and Oswestry Disability Index (ODI)were observed before and 12 months after operation. All patients underwent CT examination preoperative and 12 months postoperative, and the CT values of bilateral multifidus muscle were measured. All the patients were followed up, 40 patients in traditional group were 12 to 18 months with an average of (15.3±4.3) months; and 50 patients in Wiltse approach group were 13 to 24 months with an average of (16.5± 4.1) months. There were no statistically significant differences in operative time and intraoperative blood loss between two groups (P>0.05). The accuracy of screw implantation in Wiltse approach group was higher than traditional group (P<0.05).There was no significant difference in preoperative VAS score and ODI between two groups, and 12 months after operation, VAS score and ODI in Wiltse approach group was significantly lower than traditional group (P <0.05). The postoperative drainage and drainage tube placement time in Wiltse approach group were lower than the traditional group(P<0.05). There was no statistically significant difference in CT value of multifidus muscle before operation between two groups (P>0.05), while there was statistically significant difference after operation (P<0.05). Postoperative CT values of multifidus muscles on decompression and non-decompression side were obviously reduced in traditional group (P<0.05). The CT value of the multifidus muscle on the decompression side of the Wiltse approach group was significantly lower than that before operation(P<0.05), and there was no significant difference before and after the operation on the non-decompression side (P>0.05). Compared with traditional surgical procedures, the Wiltse approach nail placement combined with contralateral TLIF has the advantage of accurate nail placement, reducing multifidus muscle damage, and reducing the incidence of postoperative intractable low back pain.

Midline lumbar interbody fusion (MIDLIF) with cortical screws: initial experience and learning curve.

A variety of surgical techniques can be used to achieve lumbar spinal fusion for management of degenerative conditions. Transforaminal lumbar interbody fusion (TLIF) is the most popular technique; however, midline lumbar interbody fusion (MIDLIF) is a valid alternative to the more traditional pedicle screw trajectory with potential advantages. The aim of this study is to evaluate the clinical outcomes from a cohort of patients submitted to MIDLIF in a single hospital during the surgical team's initial learning period. The first 30 consecutive patients who underwent single- or two-level MIDLIF surgery for lumbar degenerative disease were included in this retrospective study. Patients' demographics, surgical data, length of hospitalisation, and perioperative complications were analysed. Preoperative and postoperative radiographic parameters were obtained. Validated questionnaires, Core Outcome Measure Index for the back, Euro-QoL 5-Dimensional Questionnaire, and Oswestry Disability Index, were used for clinical assessment. Mean surgery time was 278.53 ± 82.16 min and mean hospitalisation time was 6.17 ± 3.51 days. Six patients experienced complications, four of which being dural tears with no consequences, and two required reoperations during the mean follow-up of 25.23 ± 9.74 months. Preoperative and postoperative radiological parameters did not demonstrate significant differences. All clinical parameters significantly improved after surgery (p < 0.001). A complexity score was developed to more accurately compare the different procedures, and it strongly correlated with surgery duration (r = 0.719, p < 0.001). Furthermore, a moderate correlation was found between a developed Duration Index and the patient's order number (r = - 0.539, p = 0.002). In our initial experience, MIDLIF showed to be effective in significantly improving the patients' functional status, pain scores, and quality of life. The technique seems safe, with an acceptably low complication rate. Hence, MIDLIF can be considered as a promising alternative to more traditional TLIF and PLIF techniques even at the beginning of the learning curve.

Comparison of adjacent segment degeneration following single-segment minimally invasive and open transforaminal lumbar interbody fusion

Objective To compare the incidence of adjacent segment degeneration (ASDeg) and clinical outcomes of minimally invasive versus traditional transforaminal lumbar interbody fusion (TLIF) in the treatment of L 4,5 single-segment lumbar spinal stenosis (LSS) and explore the risk factors of ASDeg. Methods All of 115 patients with LSS who were treated by the same group of doctors from 2009 to 2013, with a minimum follow-up of 5 years. Thirty-eight patients underwent minimally invasive trans-foraminal lumbar interbody fusion (MIS-TLIF) and 77 patients underwent traditional TLIF. Standing radiographs at the preopera-tive period and the final follow-up were assessed. Radiological parameters included lumbar lordosis (LL), fused segment angle (FSA), disc height (DH) and range of motion (ROM). Babu classification was used to identify facet joint violation (FJV) in patients at 5-year follow-up. Clinical outcomes were assessed according to visual analog scale (VAS) score, Japanese Orthopaedic Associa-tion (JOA) score and Oswestry Disability Index (ODI). Student's t-test, Chi-square test, and non-parametric test were used as the main statistical methods. Results The mean age of MIS-TLIF group was 58.2±8.8 years, and that of TLIF group was 54.7±11.2 years, and there was no significant difference between the two groups. The mean follow-up time was 64.5±3.8 months in the MIS-TLIF group and 63.9±3.3 months in the TLIF group, and there was no significant difference between the two groups. There were 17 cases of degenerative spondylolisthesis in MIS-TLIF group (44.7%) and 35 cases of degenerative spondylolisthesis in TLIF group (45.5%), and there was no significant difference between the two groups. There was no significant difference in DH and ROM of L3,4, L4,5, L5S1 between the two groups before operation. There was no significant difference in VAS, JOA and ODI scores between the two groups before operation. The VAS, JOA and ODI scores were significantly improved at the last follow-up compared with those before operation. After 5-year follow-up, 56 cases (48.7%) had ASDeg. The incidence of ASDeg was 31.6% in MIS-TLIF group and 57.1% in TLIF group, and there was statistical differences between the two groups (χ2=6.656, P <0.01). Among them, 32 cases only had upper segment ASDeg (6 cases in MIS-TLIF group, 26 cases in TLIF group), 19 cases only had lower segment ASDeg (6 cases in MIS-TLIF group, 13 cases in TLIF group), and 5 cases had both upper and lower ASDeg (5 cases in the TLIF group). The DH of adjacent segments decreased after operation, but the loss of DH in MIS-TLIF group was smaller than that in TLIF group, including L3,4 segments (-4.9%±6.4% vs-8.7%±7.2%, t=-2.761, P <0.01), L5S1 segment (-4.7%±9.8% vs-10.5%±11.7%, t=-2.623, P <0.01). The ROM of adjacent segments increased in both groups, but the increase of ROM in MIS-TLIF group was smaller than that in TLIF group, including L 3,4 segments (1.1°±1.8° vs 2.3°±2.5°, t=-3.122, P <0.01), L5S1 segment (0.9°± 1.9 ° vs 1.8°±1.9 °, t=-2.353, P <0.01). The incidence of FJV was 54.2% in patients with ASDeg in MIS-TLIF group and 47.7% in patients with ASDeg in TLIF group. Chi-square analysis showed that FJV was related to ASDeg in both groups (χ2=3.869, P < 0.05). Conclusion Both of the two surgical methods have good clinical effects on L 4,5 single-segment LSS. The incidence of AS-Deg after MIS-TLIF is lower than that of TLIF. FJV is a risk factor for ASDeg. Key words: Lumbar vertebrae; Spinal stenosis; Spinal fusion; Surgical procedures, minimally invasive; Postoperative complications

Comparison of Segmental Lordosis and Global Spinopelvic Alignment After Single-Level Lateral Lumbar Interbody Fusion or Transforaminal Lumbar Interbody Fusion

Lateral lumbar interbody fusion (LLIF) has steadily increased in popularity. Compared with the traditional transforaminal lumbar interbody fusion (TLIF), LLIF is thought to allow for greater improvement in lordosis. However, there are limited direct comparison data on the degree of regional and global alignment change after single-level LLIF and TLIF procedures. This study compared the changes in spinal sagittal alignment in patients who underwent either procedure. A retrospective analysis of patients who underwent LLIF or TLIF for lumbar degenerative disease at a single institution was performed. Twenty patients who underwent single-level LLIF were matched to 20 patients who underwent single-level TLIF by gender and level of interbody fusion. All included patients had preoperative and postoperative standing scoliosis radiographs. Changes in segmental lordosis (SL) at the fused level, lumbar lordosis (LL), sagittal vertical axis, and pelvic incidence-LL mismatch (PI-LL) were measured. Statistical analysis was performed using paired and unpaired Student's t-tests. Means were reported with standard error. Within each group, 2, 4, and 14 patients had cages placed at L2-3, L3-4, and L4-5, respectively. The LLIF group demonstrated significantly increased SL compared with the TLIF group (+4.9° ± 3.0 vs.+2.6° ± 1.7, P= 0.01). LL, sagittal vertical axis, and PI-LL changes did not differ significantly between groups. LLIF achieved greater improvements in SL than TLIF. However, regionally and globally, there were no significant differences with either procedure after a single-level intervention. The increased lordosis from LLIF compared with TLIF may be more impactful globally in multilevel fusions.

Radiation exposure with hybrid image-guidance-based minimally invasive transforaminal lumbar interbody fusion

The transforaminal lumbar interbody fusion (TLIF) is used for the treatment of back and leg pain secondary to spinal stenosis, degenerative disc disease, and spondylolisthesis. Minimally invasive surgery (MIS) is associated with less estimated blood loss (EBL), decreased length of stay, lower infection rates, and similar outcomes compared to the traditional TLIF. Fluoroscopy time has been reported with MIS-TLIF, but there are limited data on specific radiation dosages. We performed a retrospective analysis of a prospectively acquired cohort of patients undergoing MIS-TLIF. A total of 50 patients were included. Mean age was 53 years with 60% women and mean BMI of 30 (range 21–41). Diagnoses were as follows: 45 stenosis (90%), 29 spondylolisthesis (58%), 5 facet cysts (10%), 3 scoliosis (6%), and 1 cauda equina syndrome (2%). A single level was fused in 33 cases (66%), two levels in 15 (30%), three levels in 2 (4%). Average cage height was 10 mm with mean EBL of 80 ml and operative time of 240 min. The average radiation doses from intraoperative CT scan and fluoroscopy were 35.3 and 26.5 mGy, respectively. Average CT scan and fluoroscopy times were 5.2 and 37.1 s, respectively, for a total of 42.2 s. Average length of stay was 3 days (range 1–7 days). Although these data represent a preliminary experience, by streamlining the timing of intraoperative CT scan and minimizing the amount of intraoperative fluoroscopy, this protocol has the potential for decreasing operative time and radiation exposure.

Curative effect of Quadrant channel transforaminal lumbar interbody fusion in the treatment of recurrent lumbar disc herniation

Objective To investigate the curative effect of Quadrant channel transforaminal lumbar interbody fusion(TLIF) in the treatment of recurrent lumbar disc herniation(RLDH). Methods Seventy-six cases patients with RLDH were divided into traditional TLIF group(36 cases) and Quadrant group(40 cases) by the different operation modes.The operation, VAS scores and ODI scores were compared between the two groups. Results Operation time((98.2±18.1) min vs.(118.5±27.2) min, t=3.79, P<0.05), incision length((2.7±0.6) cm vs.(5.5±1.0) cm, t=14.97, P<0.05), intraoperative blood loss((90.7±20.1) ml vs.(170.3±33.5) ml, t=12.71, P<0.05) and intraoperative drainage((43.8±12.4) ml vs.(117.1±28.9) ml, t=14.62, P<0.05) in Quadrant group were less than that in traditional TLIF group.The ambulation time((2.8±0.6) d vs.(6.8±1.1) d, t=19.95.P<0.05) and hospitalization time((7.1±2.0) d vs.(14.2±2.7) d, t=13.11, P<0.05) of Quadrant group were shorter than those of TLIF group.VAS scores in both groups were significantly decreased.VAS in Quadrant group was significantly lower than that in traditional TLIF group from 3 d to 6 months after operation((4.4±1.0, 3.9±1.2, 3.4±0.8, 1.9±0.6, 1.3±0.4) points vs.(5.0±1.4, 4.5±1.1, 4.1±0.9, 3.6±0.7, 2.5±0.6) points, P<0.05). ODI scores in both groups were significantly decreased.ODI in Quadrant group was significantly lower than that in traditional TLIF group from 1 d to 6 months after operation((36.7±7.1, 33.4±6.2, 30.7±4.1, 27.8±5.3, 24.5±5.4, 18.4±4.7) points vs.(39.8±6.0, 36.8±5.8, 33.5±6.6, 31.3±5.1, 28.9±6.6, 22.3±5.2) points, P<0.05). Conclusion The treatment of RLDH by Quadrant channel TLIF has obvious curative effect, short operation time, less trauma, faster recovery and shorter hospital stay. Key words: Quadrant channel; Transforaminal lumbar interbody fusion; Recurrent lumbar disc herniation

Improvement of Segmental Lordosis in Transforaminal Lumbar Interbody Fusion: A Comparison of Two Techniques.

Study Design Retrospective review. Objective The purpose of this study was to determine the radiographic impact of a transforaminal lumbar interbody fusion (TLIF) versus a cantilever TLIF technique on segmental lordosis, segmental coronal alignment, and disk height. Methods A retrospective review was done of all patients undergoing TLIF procedures from 2006 to 2011 by three spine surgeons. Traditional TLIF versus cantilever TLIF results were compared, and radiographic outcomes were assessed. Results One hundred one patients were included in the study. Patients undergoing the cantilever TLIF procedure had a significantly greater change in segmental lordosis and disk height compared with those who underwent the traditional procedure (p > 0.0001). Conclusions The cantilever TLIF technique can lead to greater change in segmental lordosis based upon radiographic outcomes.

Biomechanical analysis of various footprints of transforaminal lumbar interbody fusion devices.

A biomechanical finite element modeling study of the human lumbar spine. To evaluate the effects of a transforaminal interbody device's footprint on lumbar spine biomechanics to further examine the potential subtle biomechanical differences not captured in previous studies. In recent years, the evolution of interbody fusion devices has provided the surgeons with a multitude of options. An articulating transforaminal lumbar interbody fusion (TLIF) device is developed to overcome the surgical challenges associated with insertion of a large footprint interbody device through a small incision. A finite element model of the L3-S1 lumbar segment was modified to simulate replacement of various TLIF constructs with different cage designs including an articulating vertebral interbody (AVID) TLIF device and a generic TLIF device placed in different configurations. The instrumented models were subjected to a 400 N follower load along with a 10 N m bending moment at different physiological planes. The kinematics, loads, and stresses were compared among various models. Simulated cage designs provided similar kinematical stability within the treated segments. However, the articulating and double TLIF implants allowed for better load sharing through the anterior column. These implants resulted in lower endplate and pedicle screw stresses and in more homogenous stress distribution across the peripheral region of the endplate. An articulating, large footprint, peripherally placed TLIF device affords substantial biomechanical advantages. This device may be able to reduce the incidence of subsidence because of its ability to reduce and distribute the endplate stresses in the stronger peripheral region. It may also reduce the posterior hardware failure incidence owing to its ability to reduce the screw stresses as compared with traditional TLIF. Although double TLIF has been demonstrated to have similar biomechanical advantages as the AVID, complications associated with double TLIF (ie, larger surgical incision, longer surgical procedure, placement and alignment challenges) support AVID as a better optimized alternative.

Navigation-assisted minimally invasive transforaminal lumbar interbody fusion versus traditional fluoroscopy-assisted open transforaminal lumbar interbody fusion for adult lumbar spondylolisthesis——a randomized controlled trial

Objective To compare the clinical outcomes of navigation-assisted minimally invasive transforaminal lumbar interbody fusion (TLIF) with traditional fluoroscopy-assisted open TLIF.Methods Between May 2011 and March 2013,27 eligible adult patients with lumbar spondylolisthesis were randomly assigned to receive navigation-assisted minimally invasive TLIF (13 cases) or traditional fluoroscopy-assisted open TLIF (14 cases).The 2 groups were compatible with no significant differences in preoperative general data (P ＞ 0.05).The 2 groups were compared in terms of operation time,intraoperative blood loss,hospital stay,post-operative Japanese Orthopaedic Association (JOA)score,Oswestry disability Index (ODI)score,visual analogue scale (VAS) score,Odom' s evaluation,and rates of good to excellent pedicle insertion,olisthe,reduction and fusion.Results The navigation-assisted TLIF and traditional TLIF groups were followed up respectively for 12.4 and 11.5 months on average.The navigation-assisted minimally invasive TLIF group had significantly less blood loss,greater JOA improvement and lower ODI scores than the traditional open TLIF group (P ＜ 0.05).There were no significant differences between the 2 groups regarding operation time,hospital stay,VAS score,Odom's evaluation,or rates of good to excellent pedicle insertion,olisthe,reduction and fusion (P ＞ 0.05).Conclusion Since navigation-assisted minimally invasive TLIF has advantages of decreased intraoperative blood loss,minimal invasion and accurate pedicle insertion compared with traditional open TLIF,it has a promising prospect of clinical application. Key words: Lumbar vertebrae; Surgery, computer-assisted; Surgical procedures, minimally; Spondylolysis

Lumbar degenerative spinal deformity: Surgical options of PLIF, TLIF and MI-TLIF

Degenerative disease of the lumbar spine is common in ageing populations. It causes disturbing back pain, radicular symptoms and lowers the quality of life. We will focus our discussion on the surgical options of posterior lumbar interbody fusion (PLIF) and transforaminal lumbar interbody fusion (TLIF) and minimally invasive transforaminal lumbar interbody fusion (MI-TLIF) for lumbar degenerative spinal deformities, which include symptomatic spondylolisthesis and degenerative scoliosis. Through a description of each procedure, we hope to illustrate the potential benefits of TLIF over PLIF. In a retrospective study of 53 ALIF/PLIF patients and 111 TLIF patients we found reduced risk of vessel and nerve injury in TLIF patients due to less exposure of these structures, shortened operative time and reduced intra-operative bleeding. These advantages could be translated to shortened hospital stay, faster recovery period and earlier return to work. The disadvantages of TLIF such as incomplete intervertebral disc and vertebral end-plate removal and potential occult injury to exiting nerve root when under experienced hands are rare. Hence TLIF remains the mainstay of treatment in degenerative deformities of the lumbar spine. However, TLIF being a unilateral transforaminal approach, is unable to decompress the opposite nerve root. This may require contralateral laminotomy, which is a fairly simple procedure. The use of minimally invasive transforaminal lumbar interbody fusion (MI-TLIF) to treat degenerative lumbar spinal deformity is still in its early stages. Although the initial results appear promising, it remains a difficult operative procedure to master with a steep learning curve. In a recent study comparing 29 MI-TLIF patients and 29 open TLIF, MI-TLIF was associated with longer operative time, less blood loss, shorter hospital stay, with no difference in SF-36 scores at six months and two years. Whether it can replace traditional TLIF as the surgery of choice for degenerative lumbar deformity remains unknown and more studies are required to validate the safety and efficiency.

The anatomic study and clinical significance of the modified transforaminal lumbar interbody fusion

To put some improvements to the traditional transforaminal lumbar interbody fusion (TLIF) and discuss its clinical significance. Completed the traditional posterior lumbar interbody fusion (PLIF) and TLIF procedure in 12 fresh cadavers, dissect further to expose the surrounding anatomical structures, and put the modified TLIF surgery according to the anatomical findings. And simulated the operation in 12 fresh cadavers, analyzed its feasibility and potential advantages. The early anatomical study found that the related nerve root was in a state of high tension and certain risk of injury when completed the traditional PLIF and TLIF surgery, and found certain operational area between the superior articular process and the midline structures of the spinous processes and interspinous ligaments. Put the modified TLIF surgical approach according to the anatomical findings, which the operating area is located in PLIF outside and TLIF inside. As the following words: Take a posterior-middle incision, preserve the supraspinous and interspinous ligaments, and the spinous processes, dissect the bilateral paravertebral muscle, expose lamina and facet joints, not including transverse process, and remove unilateral inferior two third lamina, inferior articular process and expose the articular surface of the superior articular process, then dispose the intervertebral space for interbody fusion obliquely in the unilateral approach. Successfully completed the modified TLIF procedure in 12 fresh cadavers, the results showed that the technique has the following advantages. (1) Only remove unilateral inferior two third lamina and inferior articular process, preserve the supraspinous and interspinous ligaments, and the spinous processes, not expose the transverse process. (2) Both central canal, and lateral recess and nerve root canal of the operative side can be decompressed effectively simultaneously. (3) Avoid excessive traction to the thecal sac and traversing nerve roots and decrease the injury rate due to the reservation of the midline structures and the oblique manipulation, and less injury rate of the exiting nerve root, because of not necessary to expose it routinely. The modified TLIF is safe and feasible, could effectively reduce the nerve roots injuries. Maybe it's a better choice for most of the Chinese patients at present.