Posterior lumbar interbody fusion (PLIF) is indicated for many patients with pain and/or instability of the lumbar spine. We performed 36 PLIF procedures using the patient’s lumbar spinous process and laminae, which were inserted as a bone graft between two vertebral bodies without using a cage. The mean lumbar lordosis and mean disc height to vertebral body ratio were restored and preserved after surgery. There were no serious complications. These results suggest that this procedure is safe and effective

Between March 2000 and February 2006, we carried out a prospective study of 100 patients with a low-grade isthmic spondylolisthesis (Meyerding grade II or below), who were randomised to receive a single-level and instrumented posterior lumbar interbody fusion with either one or two cages. The minimum follow-up was for two years. At this stage 91 patients were available for review. A total of 47 patients received one cage (group 1) and 44 two cages (group 2). The clinical and radiological outcomes of the two groups were compared. There were no significant differences between the two groups in terms of post-operative pain, Oswestry Disability Score, clinical results, complication rate, percentage of post-operative slip, anterior fusion rate or posterior fusion rate. On the other hand, the mean operating time was 144 minutes (100 to 240) for patients in group 1 and 167 minutes (110 to 270) for those in group 2 (p = 0.0002). The mean blood loss up to the end of the first post-operative day was 756 ml (510 to 1440) in group 1 and 817 ml (620 to 1730) in group 2 (p < 0.0001). Our results suggest that an instrumented posterior lumbar interbody fusion performed with either one or two cages in addition to a bone graft around the cage has a low rate of complications and a high fusion rate. The clinical outcomes were good in most cases, regardless of whether one or two cages had been used

There are few reports on the treatment of pyogenic lumbar spondylodiscitis through the posterior approach using a single incision. Between October 1999 and March 2003 we operated on 18 patients with pyogenic lumbar spondylodiscitis. All underwent posterior lumbar interbody fusion using an autogenous bone graft from the iliac crest and pedicle screws via a posterior approach. The clinical outcome was assessed using the Frankel neurological classification and the criteria of Kirkaldy-Willis. Under the Frankel classification, two patients improved by two grades (C to E), 11 by one grade, and five showed no change. The Kirkaldy-Willis functional outcome was excellent in five patients, good in ten and fair in three. Bony union was confirmed six months after surgery in 17 patients, but in one patient this was not achieved until two years after operation. The mean lordotic angle before operation was 20° (−2° to 42°) and the mean lordotic angle at the final follow-up was 32.5° (17° to 44°). Two patients had a superficial wound infection and two a transient root injury. Posterior lumbar interbody fusion with an autogenous iliac crest bone graft and pedicle screw fixation via a posterior approach can provide satisfactory results in pyogenic spondylodiscitis

There are few reports of the treatment of lumbar tuberculous spondylitis using the posterior approach. Between January 1999 and February 2004, 16 patients underwent posterior lumbar interbody fusion with autogenous iliac-bone grafting and pedicle screw instrumentation. Their mean age at surgery was 51 years (28 to 66). The mean follow-up period was 33 months (24 to 48). The clinical outcome was assessed using the Frankel neurological classification and the Kirkaldy-Willis criteria. On the Frankel classification, one patient improved by two grades (C to E), seven by one grade, and eight showed no change. The Kirkaldy-Willis functional outcome was classified as excellent in eight patients, good in five, fair in two and poor in one. Bony union was achieved within one year in 15 patients. The mean pre-operative lordotic angle was 27.8° (9° to 45°) which improved by the final follow-up to 35.8° (28° to 48°). Post-operative complications occurred in four patients, transient root injury in two, a superficial wound infection in one and a deep wound infection in one, in whom the implant was removed. Our results show that a posterior lumbar interbody fusion with autogenous iliac-bone grafting and pedicle screw instrumentation for tuberculous spondylitis through the posterior approach can give satisfactory results

Failed Back Surgery Syndrome (FBSS) refers to having persistent back and/or leg pain after one or more surgical procedures aimed at correcting lumbosacral disease. Different modalities including Epidural injections, Spinal cord stimulation, Anterior/Posterior Lumbar Interbody Fusion (ALIF, PLIF) have been described in the literature with varying outcome. Our aim was to review the functional outcome of patients treated with Posterior Lumbar Interbody Fusion for FBSS since June 2000 to December 2006. This is a retrospective study of prospectively collected data of 25 patients diagnosed with FBSS and treated with PLIF at University Hospital of North Tees. All patients were requested to fill in the Oswestry Disability Index(ODI), Numerical Rating Scale for Back Pain (NRSBP), Numerical Rating Scale for Leg Pain (NRSLP), SF36 pre and post operatively. The scores were analysed using SPSS software for statistical significance. There were 12 men and 13 women. Mean age was 47.8 years (range 31–76 years). Mean follow up was 24.8 months (range 4 – 63 months). Four of the 25 patients had Post discectomy syndrome while the rest had post laminectomy syndrome. Most common level of surgery was L5/S1 either as a single level or in combination with other levels above. ODI decreased from a pre-op mean of 55.6(range 20–74.1) to 20.6(range 2–54) while VASBP decreased from 6.9 (range 1–9) to 2.2(range 0–6) (p< 0.05) and VASLP decreased from 6.4 (range 3–10) to 2.2 (range 0–7) (p< 0.05). SF36BP scores improved from a mean 26.7 (range 12–37.1) before the surgery to 45 (range 31–62) (p< 0.05) after surgery. 84% of the patients felt that the outcome of the surgery met their expectation and were satisfied with result. Our results show that PLIF can be offered as a safe and effective for treatment of FBSS

Inflammatory markers such as the C-reactive protein (CRP), white blood cell count and body temperature are easy to measure and are used as indicators of infection. The way in which they change in the early post-operative period after instrumented spinal surgery has not been reported in any depth. We measured these markers pre-operatively and at one, four, seven and 14 days postoperatively in 143 patients who had undergone an instrumented posterior lumbar interbody fusion. The CRP proved to be the only sensitive marker and had returned to its normal level in 48% of patients after 14 days. The CRP on day 7 was never higher than that on day 4. Age, gender, body temperature, operating time and blood loss were not related to the CRP level. A high CRP does not in itself suggest infection, but any increase after four days may presage infection

Posterior lumbar interbody fusion is a well-described procedure for the treatment of back pain associated with degenerative disc disease and segmental instability. It allows decompression of the spinal canal and circumferential fusion through one posterior incision. The aim of this study is to assess fusion rate as well as long term outcome of this procedure. Methods: Fifty-six consecutive patients who underwent posterior lumbar interbody fusion (PLIF) using carbon cages and pedicle fixation between 1993 and 2000 were recruited and contacted with postal survey. Clinical outcome was measured using changes in Oswestry Disability Index (before the surgery and at the time of the study) and patient questionnaire containing pain improvement, analgesic use, return to work and satisfaction with surgical outcome. Fusion rate was assessed using standard X-rays with scoring system described by Brantigan and Steffee. Results: The average age of the patients at the time of surgery was 43 years. The complication involved one misplaced pedicle screw, one dural tear, one deep infection, one displacement of the cage and one pulmonary embolism. The mean postoperative duration at the time of the study was 4.4 years. The response rate to the survey was 84%. Overall radiological fusion rate was 94%. There was a significant improvement in Oswestry Disability Index P< 0.001. Eighty five percent of the patients were satisfied with their surgical outcome and fifty eight percent of the work eligible patients had resumed their pre-disease activity level and full employment. Conclusions: The combination of posterior lumbar inter-body fusion (PLIF) with posterolateral instrumented fusion is a safe and effective method of achieving circumferential segmental fusion. This procedure gives sustained long-term improvement in functional outcome and high satisfaction rate

Introduction: posterior lumbar interbody fusion can theoretically allow neural decompression directly and by restoration of disc height and appropriate lumbar lordosis. The technique of insertion of a trapezoidal lordotic wedge spacer (ramp) into the disc space before rotating it into position theoretically will obtain both an increase in disc height and allow correction of lordosis. However observations suggest that incongruity between a flat implant and a curved end plate, and possible settling of the implant into the vertebral body may limit the ability of the technique to achieve its full theoretical potential. This paper attempts to establish the capacity of this technique to (1) restore disc height, and (2) alter segmental lordosis. Methods: pre- and post-operative lateral radiographs were obtained from 34 patients who had undergone posterior lumbar interbody fusion using carbon fibre spacers with a lordotic angle of five degrees. Supplemental pedicle screws were used in all cases. The procedure was performed at l2/3 in one case, at l3/4 in two cases, at l4/5 16 cases and l5/1 in 15 cases. Measurements of pre- and post-operative lordosis, anterior and posterior disc height, slip percentage and anterior and posterior positioning of the prosthesis were made. To allow for comparison of length measurements the raw data were normalised by dividing by the inferior end plate length. Results: stepwise multiple linear regression showed the only variable to be related to final post-operative lordosis was pre-operative lordosis (p = 0.026). There was no relationship between final lordosis and implant placement or slip percentage. The regression line suggested that small pre-operative segmental angles (less than 7.5 degrees) were increased post-operatively while large pre-operative angles (greater than 7.5 degrees) were reduced. This suggests that the segment is attempting to accommodate to the five-degree implant. The regression equation only explains 14% of the total variance (r. 2. = 0.144). The mean normalised posterior disc height increased significantly by 55% (0.1195 to 0.1844) (paired t test p < 0.0001) and the mean normalised anterior disc height increased by 18% (0.27151 to 0.32251) (paired t test p < 0.007). Changes in both anterior and posterior disc height were highly correlated with pre-operative disc height (r = −0.6729 p < 0.0001, r = −0.7402 p < 0.0001). Discussion: posterior lumbar interbody fusion using a five degree wedged spacer can lead to significant improvements in anterior and posterior disc height when the disc space is narrowed and maintain disc height when the disc height is normal. The insertion of a wedged implant causes the segment to approximate the lordosis of the implant. The variation is however large. Possible causes for this variation are a mismatch between the flat implant and a curved end plate and end plate subsidence. Having a curved implant end plate and a selection of lordotic angles may possibly reduce the former effect

The post-operative changes in the serum levels of CRP and serum amyloid A (SAA) were investigated prospectively in 106 patients after posterior lumbar interbody fusion. In 96 patients who did not have complications related to infection within the first year after operation, the median levels of CRP before operation and on days 3, 7 and 13 after were 0.02 (0.01 to 0.03), 9.12 (2.36 to 19.82), 1.64 (0.19 to 6.10) and 0.53 (0.05 to 2.94) mg/dl, respectively and for SAA, 2.6 (2.0 to 3.8), 1312.1 (58.0 to 3579.8), 77.3 (1.8 to 478.4), 14.1 (0.5 to 71.9) μg/ml, respectively. The levels on day 3 were the highest for both CRP and SAA and significantly decreased (p < 0.01) by day 7 and day 13. In regard to CRP, no patient had less than the reference level (0.1 mg/dl) on day 7. In only three had the level decreased to the reference level, while in 93 it was above this on day 13. However, for SAA, the levels became normal on day 7 in 10 cases and on day 13 in 34 cases. The ratios relative to the levels on day 3 were significantly lower for SAA compared with CRP on day 7 and day 13. Of the ten patients with infection in the early stages, the level of CRP decreased slightly but an increase in SAA was observed in six. We concluded that SAA is better than CRP as a post-operative inflammatory marker

Introduction: Since Briggs and Milligan. 1. first described posterior lumbar interbody fusion (PLIF) in 1944, posterior lumbar interbody fusion has been a controversial fusion technique. Reports regarding the safety, efficacy and fusion rates have varied greatly over the years. Modern pedicle screw instrumentation and the use of intervertebral spreaders / implants have provided a powerful technique for the restoration of spinal balance in degenerative deformity. Since 1993, the author has performed over 400 posterior interbody fusions for a wide variety of degenerative, traumatic and neoplastic conditions. A review was undertaken of 362 consecutive patients who were managed with this technique between October 1993 and July 2001. The purpose of this review was to determine the efficacy and safety of the technique and in particular, to attempt to identify those factors, which have contributed to patient outcomes. Methods: The first 86 patients underwent wide posterior decompression with resection of facet joints and interbody grafting using morcellised posterior elements and pedicle screw stabilisation. From February 1995, the interbody graft was supplemented with Carbon wedge shaped spacers bearing serrated upper and lower surfaces (Ramps). From July of 1996 (patient 170), the interbody graft was supplemented with posterior grafting, and from December 2000 with Autologous Growth Factor (AGF) treated graft. Patient pre-operative, operative and post-operative data and complications and follow-up Surgeon Subjective Outcome Assessments (SSOA’s) were acquired prospectively. Questionnaires were administered seeking patient generated follow-up data, including Patient Subjective Outcome Assessment (PSOA). Results: Follow-up data (SSOA ± PSOA) was available on 327 or 91% of patients. The data was for periods greater than 6 months in 64% of patients. PSOA data was available on 31% – mean follow-up time for these patients was 27.7 months (± 25.8). Average age at surgery was 56 years (± 16). Average number of levels operated was 1.5 (± 0.9). Average number of previous surgeries was 0.7 (± 1.0). 286 patients were private and 76 were compensation. 88 patients had no deformity while the remainder had some form of deformity, the most common of which were spondylolisthesis – 156 and scoliosis – 94. Overall, private patients did much better (very good or excellent outcomes) than compensation ones: 76% vs. 57% (p < 0.002). Patients who underwent surgery for conditions associated with deformity did significantly better than those without: 80% vs. 57% (p < 0.01). The outcomes since the introduction of interbody serrated spacers and additional posterior grafting have been significantly improved: for private patients, 86% now vs. 62% (p < 0.002). The introduction of ramps improved the non-union rate from 16.3% in the first 86 patients to 8.3% in the next 84. The addition of posterior grafting improved the non-union rate to 1.0% in the next 198 patients. There have been no non-unions since the introduction of AGF. Serious complications included three deaths, five deep infections, eight early returns to theatre for radiculopathy, four partial and one complete foot drop, four CSF leaks and one pulmonary embolus. Of the patients surveyed, 123/131 or 94% considered the surgery worthwhile and 88% said that they would have it again, if necessary. Discussion: Refinements in technique and improved patient selection have resulted in a significant improvement in clinical outcomes over the last eight years. While technically demanding, this PLIF technique now yields a high fusion rate, the ability to fully correct sagittal and coronal deformity and a high rate of good or excellent clinical outcomes: 86% in private patients

Introduction: Several recently published case series report the development of vertebral body osteolysis following the insertion of bone morphogenetic proteins (BMP) in the interbody space. The aim of this case report was to highlight the development of severe vertebral body osteolysis following posterior lumbar interbody fusion with recombinant human bone morphogenetic protein (rhBMP-2). Methods: A 62 year old male who developed adjacent segment disease 13 years after an L4/5 and L5/S1 posterolateral fusion underwent what appeared to be a successful instrumented L3/4 posterior lumbar interbody fusion using morselised posterior elements and scavenged drilled particulate interbody autograft together with a single large sized sponge of rhBMP-2. Results: He continued to experience intermittent episodes of severe low back pain following that procedure, and a CT scan performed three months post-operatively revealed severe osteolysis of the L3 and L4 vertebral bodies. Although he was a type 2 diabetic, extensive investigations did not reveal any evidence of infection. Discussion: Vertebral body osteolysis has previously been reported following the use of BMP in the interbody space. The mechanism for this is unclear, but may be due to osteoclast activation. The prevalence of this complication following the use of BMP is not known. It is recommended that a process of independent post-marketing surveillance be established to further investigate this possible complication of the use of BMP in posterior interbody fusion

Introduction: Hypothesis:- Posterior lumbar interbody fusion (PLIF) produces improvement in the MOS Short Form 36 (SF36) scores comparable to that seen in total hip replacement. Current consensus holds the surgical treatment of lower back pain as less effective or predictable than interventions performed in most other orthopaedic subspecialties. Detailed clinical and economic outcome studies are vital to justify its use in routine practice. This prospective study presents medium to long-term clinical outcome scores for PLIF which are compared with those of an operation that might be considered a modern orthopaedic gold-standard: total hip arthroplasty. Methods: The authors present 100 consecutive PLIF operations performed by the senior author between 1997 and 2004. SF36, Oswestry Disability Index (ODI), Visual Analogue Scores (VAS) and walking distances were prospectively collected and analysed in the post-operative period. Results were compared to the SF36 healthy population norms and with the outcome scores of standard total hip replacement available in the literature. Results: The mean pre-operative ODI was 49. 12 months following surgery this improved to 22. All outcomes as measured by SF36 improved following surgery. The VAS for back pain improved from 8.5 pre-operatively to 3.21 post-operatively. Leg pain improved from 6.98 to 2.85. Improvements in the SF36 scores were similar to those seen in hip arthroplasty. Discussion: The hypothesis has been proven. The gains in function following spinal fusion are comparable with those seen in hip arthroplasty. In the authors’ opinion PLIF is an effective procedure in an appropriately selected patient population

Posterior lumbar interbody fusion is a well described procedure for the treatment of back pain associated with degenerative disc disease and segmental instability. It allows decompression of the spinal canal and circumferential fusion through a single posterior incision. Sixty-five consecutive patients who underwent posterior lumbar interbody fusion (PLIF) using carbon cages and pedicle fixation between 1993 and 2000 were recruited and contacted with a postal survey. Clinical outcome was assessed by the assessment of postoperative clinical findings and complications and the fusion rate, which was assessed using standard X-rays with the scoring system described by Brantigan and Steffee. Functional outcome was measured by using improvement in the Oswestry Disability Index, PROLO score, return to work and satisfaction with the surgical outcome. The determinants of functional relief were analysed against the improvement in disability using multiple regression analysis. The mean postoperative duration at the time of the study was 4.4 years. The response rate to the survey was 84%. Overall radiological fusion rate was ninety eight percent. There was a significant improvement in Oswestry Disability Index P< 0.001. There was 85% satisfaction with the surgical procedure and 58% return to pre-disease activity level and full employment. In the presence of near total union rate we found preoperative level of disability to be best the determinant of functional recovery irrespective of age or the degree of psychological morbidity (p< 0.0001). The combination of posterior lumbar interbody fusion (PLIF) and posterior instrumented fusion is a safe and effective method of achieving circumferential segmental fusion. This procedure gives sustained long-term improvement in functional outcome and high satisfaction rate. Direct relationship between preoperative level of disability and functional recovery suggests that spinal fusion should be performed to alleviate disability caused by degenerative spine

The aim of this study is to assess the success of posterior lumbar interbody fusion in the treatment of degenerative spinal instability. Methods: Historical prospective study containing sixty-five consecutive patients who underwent posterior lumbar interbody fusion (PLIF) using carbon cages and pedicle fixation between 1993 and 2000. Clinical outcome was assessed by the postoperative symptomatic relief, complications rate and the fusion rate. The fusion rate was assessed using plain radiographs and the Brantigan and Steffee scoring system. Functional outcome was measured by the improvement in the Oswestry disability index, PROLO score, return to work and satisfaction with the surgical outcome. The determinants of functional relief were analysed against the improvement in disability using multiple regression analysis. Results: Overall fusion rate was ninety eight percent. There was a significant improvement in Oswestry disability index P< 0.001. There was 85% satisfaction with the surgical procedure and 58% return to pre-disease activity level. We found preoperative level of disability to be best the determinant of functional recovery irrespective of age or the degree of psychological morbidity (p< 0.0001). Conclusion: The combination of posterior lumbar interbody fusion (PLIF) and posterior instrumented fusion is a safe and effective method of achieving segmental fusion with sustained functional relief and high satisfaction rate. Direct relationship between preoperative level of disability and functional recovery suggests that spinal fusion should be performed to alleviate disability caused by degenerative spine

Posterior lumbar interbody fusion (PLIF) enables us to perform posterior decompression and anterior reconstruction with single posterior midline approach. We designed trapezoid titanium mesh cage (TPM type N cage) to realign postoperative normal lordotic curve that prevents the progressive degeneration of the disc adjacent to the PLIF-D. Patients: We had 60 PLIFs by using TPM type N cage. There were 41 males and 19 females. The age was 52.6 year-old in average. The patients consisted of 19 degenerative spondylolisthesis, 12 multiply operated back syndromes (MOB), 16 intracanal ossifications, 5 spondylolytic spondylolisthesis, 7 unstable spines, 3 spinal canal stenosis. Operation methods: Intracanal or extracanal approach was used. The reduction was achieved by restoring the disc heights with rotating disc shaver. The posterior 2/3 endplate were preserved to prevent the cage from sinking into the vertebral body. TPM type N cage with 13mm anterior, 11mm posterior height was used. The trapezoid shape reestablished the lordotic curvature. Results: Mean follow-up period was 3.3 years (4.4–2.6 years). We evaluated the clinical results with Japanese Orthopedic Association score (JOA score). The preoperative 15.8 JOA score statistically improved to 25.0 in average. There was neither postoperative neurological deterioration nor contamination. Pre-operative 6.4 ± 3.2 mm disc height was statistically improved to 11.5 ± 1.8 mm. Pre-operative 6.4 ± 10.8° lumbar lordotic was statistically improved to 10.5 ± 3.9° The progressive degeneration of the disc adjacent to PLIF was identified in 7case (11%). They had no clinical symptoms. Conclusion: Trapezoid titanium mesh cage reestablishes lumbar lordotic curvature and prevents progressive degeneration of the disc adjacent to PLIF

The aim of this study is to review the functional outcome of the patients treated with Posterior Lumbar Interbody Fusion for FBSS. This is a retrospective review of prospectively collected data of 39 patients diagnosed with FBSS and treated with PLIF between June 2000 and December 2008 by the senior author in our unit. Pain and function were evaluated by VAS for Back (VAS-BP) & leg pain (VAS-LP), Oswestry disability index (NDI) and SF-36 questionnaires, and were completed pre- & post-operatively. There were 39 patients (20 women & 19 men) and mean age at operation was 47.3 years (range of 32 to 76.1 years). Mean duration of follow-up was 39.14 months (range 5.21 -73.5 months). Thirty-one patients were diagnosed as Post laminectomy syndrome and 8 patients as post-discectomy syndrome. The mean pre and post-operative ODI values were 54.13 and 29.14 respectively. The mean pre-operative VAS back and leg pain scores were 7.38 and 6.51 respectively. The mean post-operative VAS for back and leg pain scores were reduced to 4.05 (Pre-op:7.38) and 3.69 (Mean pre-op 6.51)respectively. The mean preoperative SF-36 bodily pain component score was 27.42 and the mean postoperative score was 40.50. Four patients had uncomplicated dural tears that resolved completely. Two patients had superficial wound infection that resolved with oral antibiotics. PLIF is one of the safe and effective treatment option for FBSS and it has shown good results in our series

Introduction: Minimally-invasive techniques are being advocated increasingly for spine surgery, on the grounds that they are less traumatic and reduce postoperative recovery time. A minimally-invasive technique for posterior lumbar interbody fusion (MPLIF) has become available. In order to compare its efficiency and effectiveness with the open technique (OPLIF), a prospective audit was undertaken. Methods: Forty-seven adult patients with radicular pain resulting from isthmic or degenerative spondylolisthesis, with a slip less than 50%, and no previous surgery, elected to undergo either MPLIF (n = 23) or OPLIF (n = 24). The MPLIF procedure was performed through two, 2.5cm paramedian incisions using a tubular retractor system and dilators (METRx-MD, Medtronic Sofamor Danek, Memphis). OPLIF was performed thorugh a 10 cm midline incision. In both procedures, the listhesis was reduced using polyaxial pedicle screws, and reduction tabs or bolts (Expedium, Depuy); the disc space was distracted using interbody spacers (R-90, Metronic Sofamor Danek) and packed with iliac crest graft. Intra-operative and postoperative variables were recorded. Clinical outcomes were assessed, before and 12 months after surgery, using a visual analog scale for pain and the SF36 for function. Results: The two groups were comparable, demographically and with rspect to clinical features at inception, save that the MPLIF group had signficantly greater disc heights. Listhesis (median; interquartile range) was reduced from 25% (20–32) to 8% (1–13) after OPLIF, and from 20% (15–25) to 5% (0–10) after MPLIF. Disc height was increased from 12% (6–17) of vertebral body height to 24% (20–26) after OPLIF, from 17% (10–23) to 30% (26–36) after MPLIF. Fusion was achieved in all patients except one in the PLIF group. After OPLIF, median scores (interquartile ranges) for leg pain reduced from 8 (7–9) to 1 (0–4); scores for back pain reduced from 8 (6–8) to 2 (1–4); social functioning improved from 38 (13–57) to 82 (47–100), and in physical functioning improved from 20 (5–48) to 68 (44–86). After MPLIF, leg pain reduced from 8 (7–9) to 1 (0–3); back pain reduced from 8 (8–10) to 2 (1–4); social functioning improved from 38 (25–66) to 75 (50–91), and physical functioning improved from 20 (10–48) to 65 (34–82). All improvements within groups were significant (p = 0.000), but no statistically significant differences occurred between the groups for any outcome measure. Improvements in leg pain amounted to an 88% reduction for both groups, Back pain improved by 64% after OPLIF and by 78% after MPLIF. Duration of surgery and need for transfusion were not different between groups (5 patients required transfusion during OPLIF, and 1 during MPLIF (p = 0.09)); but the MPLIF patients had significantly shorter delays before commencing and achieving mobilization post-operatively, and had a shorter length of stay (4 days v 7 days). Discussion: Clinical outcomes after MPLIF and OPLIF were not statistically different. Both procedures reduced back pain as well as leg pain, and restored function. Although there was no detectable correlation between pain and function before treatment, relief of pain was strongly correlated with restoration of function, after treatment. The advantage of MPLIF is that promotes faster recovery and shortens hospital stay. Its only disadvantage is the need to adapt to the technology involved and becoming familiar and confident with its use

The clinical success of posterior lumbar interbody fusion (PLIF) may be limited by pseudarthrosis, defined as the absence of solid fusion 1 year after surgery. Currently, CT is used to diagnose pseudarthrosis but is not able to be conclusive earlier than 1 year after surgery. No non-invasive technique is available to reliably assess bone graft incorporation in the early phase after PLIF. Positron Emission Tomography (PET) is a nuclear imaging modality that is able to identify changes at the cellular and molecular level in an early stage, well before manifestation of anatomical changes. PET/CT with the bone seeking tracer . 18. F-fluoride allows localization and quantification of bone metabolism. This study investigates whether an . 18. F-fluoride PET/CT scan early after PLIF is able to predict the fusion status at 1 year postoperative on CT. Twenty patients after PLIF were enrolled after written informed consent. At 6 weeks and at 1 year after PLIF, intravenous injection of . 18. F-fluoride was followed by a static scan at 60 minutes (Philips, Gemini TF PET/CT). Processing of images resulted in a bone metabolism parameter i.e. standardized uptake value (SUV). This parameter was determined for 3 regions of interest (ROIs): the intervertebral disc space (IDS) and the upper and lower endplate (UE and LE, respectively) of the operated segment. Interbody fusion was scored on a diagnostic CT scan made 1 year postoperatively and was defined as the amount of complete bony bridges between vertebrae, i.e 0, 1 or 2. Based on these scores, patients were divided in either the pseudarthrosis group (score 0) or the fusion group (scores 1 and 2). Differences between groups were analyzed using the independent samples Mann-Whitney U-test. Ten patients were classified as pseudarthrosis (0 bridges: n=10) and 10 patients as fused (1 bridge: n=5, 2 bridges: n=5). Patients in the pseudarthrosis group showed significantly lower bone metabolism values in the IDS on the 6 weeks PET/CT scan compared to patients in the fusion group (SUV. IDS,6w. 13.3±5.62 for pseudarthrosis and 22.6±6.42 for the fusion group, p=0.003), whereas values at the endplates were similar (SUV. UE,6w. 20.3±5.85 for pseudarthrosis and 21.6±4.24 for the fusion group, p=0.282). Furthermore, only in the pseudarthrosis group, bone metabolism in the IDS was significantly lower than at the endplates (p=0.006). In the fusion group, bone metabolism in the IDS and at the endplates was similar (p=0.470). The PET/CT scan at 1 year postoperative showed that in the pseudarthrosis group, bone metabolism of the IDS remained lower compared to the endplates (SUV. IDS,1y. 13.2±4.37, SUV. UE,1y. 16.4±5.33, p=0.004), while in the fusion group, IDS and endplate bone metabolism was similar (SUV. IDS,1y. 13.6±2.91, SUV. UE,1y. 14.4±3.14, p=0.397). This study shows that low bone metabolism values in the IDS of the operated segment as seen on . 18. F-fluoride PET/CT 6 weeks after PLIF, is related to development of pseudarthrosis 1 year postoperatively. These results suggest that . 18. F-fluoride PET/CT might be an early diagnostic tool to identify patients prone to develop pseudarthrosis after PLIF

Study design: Prospective clinical and radiologic study. Objective: The purpose of this study was to investigate the risk factors for adjacent segment degeneration after posterior lumbar interbody fusion (PLIF). Summary of Background data: Although several authors have reported the adjacent segment degeneration after lumbar or lumosacral fusion, there is no consensus regarding the risk factors for adjacent segment degeneration. Methods: Sixty-five patients were studied after PLIF after a minimum follow up time of 6 years. Plain and flexion/ extension radiographs and MRI scans were obtained and compared to preoperative and postoperative. Progression of segment degeneration was defined as a condition in which the distinction between nucleus and annulus is lost, and the disc space is collapsed according to the grading system (Grade 1–5) described by Pfirrmann et al evaluated with T2 weighted MRI scans. Patients were divided into three groups: Group 1 with no radiological progression of disc degeneration, Group 2 with radiological progression of disc degeneration, and Group 3 with radiological progression of disc degeneration and clinical deterioration. Risk factors for progression of adjacent disc degeneration as lumbar lordosis, lordosis at the fused segment, facet sagittalization, and pre-existing disc degeneration were evaluated. The images were evaluated by two independent radiologists. Results: Fifteen patients (23%) showed no radiological progression of disc degeneration on MRI scans and were classified into Group 1. Forty patients (62%) developed some cranial or caudal deterioration of the adjacent segment without clinical deterioration and were classified into Group 2. Ten patients (15%) required reoperation for neurological and clinical deterioration caused by cranial or caudal degeneration of the adjacent disc (Group 3). No statistically significant differences were found in lumbar lordosis, lordosis at the fused segment, facet sagittalization between each group. Patients in Group 3 showed on preoperative MRI already moderate to severe alteration of the adjacent disc (mean Grade 4) compared to Group 1 (mean Grade 2) and 2 (mean Grade 2,5) (p< 0.01). Conclusion: After PLIF disc degeneration appear homogeneously at several levels cranial and caudal to fusion over the years in most of the patients (79%). Only pre-existing degeneration of the adjacent cranial and caudal segment is a potential risk factor for clinical deterioration caused by disc collapse

Objective: To demonstrate the safety, surgical efficacy and advantages of the Posterior Lumbar Interbody Fusion (PLIF) technique using posterior elements as graft material when combined with pedicle screw fixation. Design: Retrospective study assessing the Oswestry Score and Pain Intensity Score pre and post-operatively in patients undergoing disc excision and PLIF with the above technique. Subjects: Eighteen patients (6 male), mean age 44 years (range 24 – 59) with a mean follow-up of 11 months (range 9 – 14). Four subjects had undergone previous lumbar surgery. All subjects had a history of back pain with or without sciatica. Outcome measures: Pre and post-operative assessment of functional ability and pain using the Oswestry Score and Pain Intensity Score. Results: Following surgery there was marked improvement in the Oswestry Score from a mean score of 36 (+/−12) to 19 (+/−9), P< 0.0001. Likewise there was an improvement in the Pain Intensity Score from a pre-operative mean score of 4 (+/−1) to a post-operative score of 1 (+/−1), P< 0.0001. Seventeen of the eighteen patients indicated that they would have the operation again. Conclusion: Our technique is safe, effective and the results are comparable with published data. This technique provides the added benefit of utilisation of posterior elements of the spine as bone graft and hence avoids donor site problems and the risks associated with insertion of block grafts