Perioperative And Early Outcome Measures In Anterior Versus Transforaminal Lumbar Interbody Fusion For Lumbar Degenerative Disc Disease With Instability

Mbalewe C. E¹, Reith M² , Abubakar K¹, Richter M³

Abstract:

The aim of this study is to compare the perioperative and early postoperative outcome of anterior lumbar interbody fusion (ALIF) and transforaminal lumbar interbody fusion (TLIF)  using patient derived outcome measures such as the Oswestry disability index (ODI) and Visual analogue score (VAS) as well as objective parameters such as intraoperative blood loss, operative time, postoperative intervertebral disc height and complications associated with each option in the treatment of degenerative lumbar disc disease with instability.
This is a retrospective analysis of 60 consecutive patients who had ALIF (30 patients) and TLIF (30 patients) for lumbar degenerative disc disease with instability between March, 2005 and March, 2007 following strict clinical and radiological diagnostic criteria.
The mean values for the postoperative change in the ODI and VAS were 13 and 34 points respectively for ALIF and 10 and 29 points respectively for TLIF. The mean  intraoperative blood loss as well as operative time were comparable. The mean postoperative intervertebral disc height for ALIF was 10.5mm while that for TLIF was 8.7mm. Complications associated with ALIF were a case each of injury to the left common iliac artery and pedicle screw loosening. There was a single case of intracanal screw placement in the TLIF group. The only parameter in which there was a statistical difference  between the two options was  the post operative disc height.
ALIF resulted in a greater increase in postoperative intervertebral disc height. It is however comparable to TLIF with respect to patient derived outcome measures.

J.Orthopaedics 2010;7(1)e1

Keywords:

Lumbar interbody fusion; Anterior; Transforaminal; Degenerative disc Disease; Instability

Introduction:

Lumbar disc degeneration is a common cause of back pain ^1,2. It may be associated with instability which has been defined as a clinically symptomatic condition without new injury in which a physiological load induces abnormally large deformation at the intervertebral joints ³. Even though there is no consensus on the radiological definition of spinal instability with disc disease ^4,5,  there is little controversy that the preferred treatment of the condition is operative with surgical fusion of the unstable segment(s) ⁶. 

Anterior lumbar interbody fusion (ALIF) and transforaminal lumbar interbody fusion (TLIF) are considered as surgical options in effecting spondylodesis ^7,18,9. With either option, further stabilization with pedicle screws is often necessary¹⁰. 

The aim of this study is to objectively assess and compare the early outcome measures in ALIF and TLIF using validated patient derived outcome measures such as the Oswestry Disability Index (ODI) version 1.0 ^11,12 and the Visual Analogue Score (VAS, 0-100mm)¹³; as well as other perioperative parameters such as the intraoperative blood loss, duration of operation, post operative disc space height and complications of each procedure.

Materials Methods:

Records of sixty consecutive patients who had had ALIF (thirty patients) or TLIF (thirty patients) for degenerative lumbar disc disease with instability at the St. Josefs - Hospital, Wiesbaden, Germany between March 2005 and March 2007 were reviewed. Patients who had documented history of recent lumbar spinal trauma, spinal neoplasm or inflammatory conditions such as rheumatoid arthritis were excluded from the study.

Diagnosis of instability was made following the recommendations of the fourth edition of the American Medical Association Guide to the Evaluation of Permanent Impairment which defines instability as an anterior slip of 5mm or more in the thoracic or lumbar spine or a difference in the angular motion of two adjacent motion segments more than 11 degrees from T1 to L5 and motion greater than 15 degrees at L5-S1 compared to L4-5 ¹⁴. These values were determined from dynamic plain radiologic examinations (Figure 1). In our study, an adjacent segment was also fused if it had an anterior slip of 3 or 4 mm.

Figure 1: Preoperative functional myelography of a patient with lumbar degenerative disc disease with instability. Note evidence of spinal stenosis in lower lumbar spine.

The ODI and VAS scores before surgery and at the third postoperative month were noted. Many of the elderly women did not respond to section 8 of the ODI questionnaire on sex life so the total score was based on the percentage value of the other nine sections. The point change in the ODI and VAS were computed from the difference between the pre and post operative values.

Pre and postoperative  intervertebral disc heights were measured digitally using the Dicom Viewer software (Convis, Mainz, Germany).

ALIF was carried out through a retroperitoneal approach to the involved vertebral segment(s) using a left paramedian abdominal incision. Pedicle screws were applied in all cases either through a posterior midline incision when there was a need for spinal  decompression or through  minimally invasive bilateral paramedian incisions when decompression was considered unnecessary.

TLIF was carried out through a midline posterior incision. Parts of adjacent facet joints were resected to gain access to the intervertebral discs. Pedicle screws were applied through the same incision in all the cases. Decompression was performed according to the clinical circumstances.

Intraoperative blood loss was calculated from total effluent in suction bottle minus amount of fluid used to irrigate the surgical wound in milliliters (ml). Values lower than 50ml were considered insignificant or negligible.

The duration of surgery was assessed from when the first skin incision was made to when the last suture was applied. In ALIF, the duration of time taken in repositioning the patient and re-draping was not included in the intraoperative protocol.

Other parameters such as the number of levels of fusion, previous back procedures, perioperative complications were also noted.

The data obtained were analyzed using the SPSS statistical software. Statistical significance was tested using 2 tailed Student t-test.

Results :

Sixty patients were involved in this study (30 in each group). For the ALIF group, the mean age of the patients at the time of surgery was 60.6 years (range 17-81years). There were 11 males and 19 females. The corresponding values for the TLIF group were 61.3 years (range 36-80years); 10 females and 20 males. In each group, 21 patients had had some previous spinal surgical procedure such as nucleotomy or facet joint coagulation. Some of the outcome measures are compared in Table 1. The P values are also stated where applicable.

ALIF anterior lumbar interbody fusion, TLIF transforaminal interbody fusion, ODI oswestry disability index, VAS visual analogue score

Operated Levels

Operation involved one level in 23 cases of ALIF and 8 cases of TLIF; two levels in 6 cases of ALIF  and 12 cases of  TLIF; three levels in one case each of ALIF and TLIF (Figure 2).

Figure 2:  Lateral and antero-posterior views of a 3-level lumbar interbody fusion using polyetheretherketone (PEEK) cages and pedicle screw

The specific levels operated are as outline in Table 1. It is important to note that 19 patients (63%) in the ALIF group had monosegmental operation at  L5/S1 (Table 2).

Table 2 Comparism of mean operative time in relation to  fused spinal level(s)

ALIF anterior lumbar interbody fusion, TLIF tranforaminal lumbar interbody fusion

Oswestry Disability index (ODI)

Pre and postoperative oswestry disability Index (ODI) scores were available in the records of 18 patients in the ALIF group and in 24 patients in the TLIF group. The mean preoperative values were 43% (Range 20-66%) and 43% (range 2-72%) respectively (Table 1). The mean postoperative ODI scores were  29% ( range 2-62%) and 33% (range 2-72%)  respectively.

The mean value of the change in ODI which is an important measure of outcome was 13%  (range -2 -32%) for the ALIF group and 10% (range -24-53%)  for the TLIF group. This result implies that in the early postoperative period, some patients had an overall deterioration in functioning.

Visual Analogue Score (VAS) 

The visual analogue score for back pain was available for 29 patients in the ALIF group and 24 patients in the TLIF group. The mean preoperative scores for ALIF and TLIF groups were 70% and 71% respectively. Post operative scores were 36% and 42% respectively. The mean change ( difference in preoperative and postoperative scores) in VAS in the ALIF group was 34% with a range of -38% to 88%: the corresponding values for the TLIF group were 29%, and 0% - 95% 

Operative Blood Loss

The mean operative blood loss was 157ml in the ALIF group (range insignificant – 1100ml) while in the TLIF group  it was 113ml (range insignificant-1000ml). Operative blood loss was considered insignificant if it was less than 50ml. In the ALIF group,  the anterior retroperitoneal dissection was usually associated with minimal blood loss.

Operative Time

The average operative time for ALIF was 142 minutes (range 55-290 minutes) while for TLIF it was 153.2minutes (range 60-240 minutes). In the ALIF approach, the retroperitoneal and posterior dissections took about the same time.

Disc Space Height

Mean preoperative disc height for ALIF was 4.4mm (range 2.4-7.8mm) while the mean postoperative height was 10.5mm (range 7.9-14.0mm). The corresponding values for TLIF were 4.6mm (range 2.4-8.8mm) and 8.7mm (range 7.8-12mm) respectively.

Complications

In the ALIF group, there was one case of intraoperative  injury  to the left common iliac artery; one case of pedicle screw loosening. In the TLIF group, there was a single case of intracanal pedicle screw placement.

Discussion :

A number of studies have shown the relative safety and effectiveness of ALIF and TLIF in the treatment of lumbar degenerative disc disease with instability^8,9 but none has compared the functional outcome of the two operative approaches for the index condition. Outcome scores and measures are important in spine surgery as they are a means of assessing a patient’s progress and a means of comparing treatment options. Increasingly, these measures include both objective and subjective criteria.

The ODI and VAS are standard validated subjective disease-specific outcome measures which are responsive to changes in clinical status^13,14.The ODI mainly assesses the patient’s ability to perform activities of daily living while the VAS assesses the patient’s perception of his or her intensity of pain. Increasing value of the ODI or the VAS, equate to increasing disability.  More relevant in assessing the  success of a procedure is the change in the score of the tool being measured. Tafazal and Sell¹⁵  in  their study on outcome scores in spinal surgery suggested that for a fusion, the change in the ODI, for the surgery to be considered as successful is 13 points. In this study, the mean change in the ODI was 13 points for ALIF and 10 points for TLIF (range -2 – 32 and -24 – 53 respectively). From the foregoing, the ALIF procedure could be considered a success based on the mean scores. However, statistical analysis did not show any statistical difference (P=0.507) between the two. Ditto for the change in the VAS where the mean points for ALIF and TLIF were 34 and 29 respectively (P=0.060).

There was a high non- response rate especially in older middle aged and elderly women to item 8 on the ODI questionnaire which relates to sex life. Other authors including the original authors of the ODI have noted this point^{16, 17}. The original authors opined that it may not be acceptable or applicable to all patients. It should be noted that these outcome measures may be affected by the psychological profile of the patient as well as post operative compensation claims.

The mean blood loss in the ALIF group was 157ml (range negligible – 1100ml). The mean value was significantly affected by a particular case complicated by injury to the left common iliac artery. The mean blood loss in the TLIF group was 113ml (range negligible- 1000ml). There was however no statistical difference between the 2 groups (P=0.55). The blood loss when the numbers of fused segments were matched was comparable in the two groups. The mean operative blood loss in this study contrasts sharply with the mean value of 424ml in a study conducted by Villavicencio et al¹¹ comparing perioperative complications in TLIF and anterior-posterior (AP) reconstruction for lumbar degenerative instability. The difference may be explained in part by the fact that all posterior dissection of the spine is carried out with a harmonic scalpel which significantly reduces blood loss especially during stripping of muscle from the spinous processes and laminae¹⁹.

The mean operative time for ALIF was 142 minutes (range 55 – 290 minutes); that for TLIF was 153 minutes (range 60 – 240 minutes). There was no statistical difference between the two groups. The operative protocol did not include the time taken to reposition and re-drape the patients in the ALIF group. This process would usually take 10 – 15 minutes and would be unlikely to lead to any significant statistical difference. Also, matching the number of fused segments for the two groups did not reveal any significant discrepancy. In the series by Villavicencio et al, the operative time for open TLIF was 222 minute. This difference may partly be attributable to some differences in operative protocol.

The operative restoration of intervertebral disc height space is an important consideration in fusion for degenerative disc disease. This manoeuvre not only restores the patient’s vertical height especially in multi-segmental disease, it also reduces or eliminates root tension consequent  upon intervertebral disc and segmental collapse. Schuler et al²⁰ have shown that there is a significant improvement in outcome scores – the ODI, VAS and the Physical Component Summary scores of the Short Form-36 following anterior release and insertion of stand alone-cages in patients with symptomatic disc degeneration.

In this study, the mean pre and postoperative disc height for ALIF was 4.4mm and 10.5mm respectively (range 7.9-14mm). The corresponding values for TLIF were 4.6mm and 8.7mm (range 7.8-12mm). The difference in the values was statistically significant. This stands to reason because in the ALIF procedure, there is disruption of the anterior longitudinal ligament in the involved segment(s) which leads to a more complete anterior release and distraction allowing for a more efficient restoration of the intervertebral disc height. In the TLIF procedure, the anterior longitudinal ligament is usually left intact. Choi and Sung²¹ noted a relatively high subsidence rate after ALIF with stand-alone cages, therefore, long term follow up is necessary to assess whether the significant increase in the disc height in the ALIF group would be sustained. 

The complications from both groups were few. In the ALIF group there were 2 complications: a case of injury to the left common iliac artery requiring repair and a case of asymptomatic pedicle screw loosening discovered incidentally during routine postoperative outpatient radiological examination. The patient had a revision with additional pedicle screws applied to the next caudal segment.

Other early complications that have been noted with the ALIF procedure include; injury to the iliac veins, ureteral injury, peritonitis, retrograde ejaculation and cage dislocation (more common with stand alone cages)⁷.In the TLIF group, there was a case of intracanal pedicle screw placement. This led to revision of the screw placement. Early complications following TLIF appear to occur infrequently; they include dural tears and nerve root injuries^8. 

Conclusion:

This study has some limitations. It is retrospective and the sample size is relatively small so strong conclusions cannot be drawn from it. However, it does appear that ALIF and TLIF are comparable options in the surgical treatment of lumbar degenerative disc disease with instability. They have similar perioperative outcome with regards to operation time, blood loss, and outcome scores. It would appear that if disc height restoration is a major goal of surgery, the ALIF procedure is the preferable option. It can also be surmised that because of the potential multisystemic complications that can occur with ALIF, it is best performed by a surgeon who is familiar with the management of various intra-abdominal organ systems or who works in a centre with such expertise.

Reference :

1. Mayer HM (2001) Discogenic low back pain and degenerative lumbar spinal stenosis – how appropriate is surgical treatment? Schmerz 15(6):484-91     

2. von Waldburg T, van Elegem P (2003) Etiologies of lumbago. Rev med Brux 24(4):A210-4

3. Farfan HF, Gracovetsky S (1984) The nature of instability. Spine 9(7):714-9

4. Nizard RS, Wybier M, Laredo JD (2001) Radiologic assessment of  lumbar              intervertebral instability and degenerative spondylolisthesis. Radiol Clinics North Am 39(1):55-57

5. Fujiwara A, Tamai K, An HS et al (2000) The relationship between disc degeneration, facet joint osteoarthritis and stability of the degenerative lumbar spine. J Spinal Disord  13(5):444-50

6. Williams KD, Park AL. Lower back pain and disorders of intervertebral discs. In Canale ST (ed): Campbell’s Operative Orthopaedics 10^th edition, Mosby Press,  Philadelphia, 2004; 1995-2028

7. Loquidice VA, Johnson RG, Guyer RD et al (1988) Anterior lumbar interbody fusion. Spine 13(3):366-9

8. Salehi SA, Tawk R, Ganju A et al (2004) Transforaminal lumbar interbody fusion: surgical technique and result in 24 patients. Neurosurgery 54(2):368-74

9. Villavicencio AT, Burneikiene S, Bulsara KR, Thramann JJ (2006) Perioperative complications in transforaminal lumbar interbody fusion versus anterior-posterior reconstruction for lumbar disc degeneration and instability. J Spinal Disord Tech 19(2):92-7

10. Hackenberg L, Halm H, Bullman V, et al (2005) Transforaminal lumbar interbody fusion: A safe technique with satisfactory three to five year results. Eur Spine J 14(6):551-8

11. Fairbank J (1995) Use of Oswestry disability index (ODI). Spine 20:1535-1537

12. Fairbank JC, Pynsent PB (2000) The Oswestry disability index. Spine 25:2940-2952

13. Dixon S, Bird H (1981) Reproducibility along a 10cm visual analogue scale. Ann Rheu Dis 40:87-8

14. American Medical Association (1993) Guides to the evaluation of permanent impairment, ed 4, Chicago, American Medical Association

15. Tafazal SI, Sell PJ (2006) Outcome scores in spinal surgery quantified: excellent, good, fair and poor in terms of patient completed tools. Eur Spine J 15:1653-1660

16. Fairbank JC (2006) Comments on “Discriminative validity and responsiveness of the Oswestry disability index among Japanese outpatients with lumbar conditions. Eur Spine J 15:1651

17. Lauridsen H H, Hartvigsen J, Manniche C et al (2006) Danish version of the Oswestry disability index for patients with low back pain. Part 1: Cross-cultural adaptation, reliability and validity in two different populations. Eur Spine J 15:1705- 1716

18. Pfeiffer M, Griss P, Haake M (1996) Standardized evaluation of  long-term results after anterior lumbar interbody fusion. Eur Spine J 5(5):299-307

19. Cakir B, Ulmar B, Schmidt R et al (2006) Efficacy and cost effectiveness of harmonic scalpel compared with electrocautery in posterior instrumentation of the spine. Eur Spine J 15:48-54

20. Schuler TC, Burkus JK, Gornet MF et al (2005) The correlation between preoperative disc height and clinical outcomes after anterior lumbar interbody fusion. J Spine Disord Tech 18(5):396-401

21. Choi JY, Sung KH (2006) Subsidence after anterior lumbar interbody fusion using paired stand-alone rectangular cages. Eur Spine J 15:16-22
     

This is a peer reviewed paper 

Please cite as: Mbalewe C.E: Perioperative And Early Outcome Measures In Anterior Versus Transforaminal Lumbar Interbody Fusion For Lumbar Degenerative Disc Disease With Instability

J.Orthopaedics 2010;7(1)e1

URL: http://www.jortho.org/2010/7/1/e1

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