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Restoration of Lumbar Lordosis in Flat Back Deformity: Optimal Degree of Correction.

Kim KT, Lee SH, Huh DS, Kim HJ, Kim JY, Lee JH - Asian Spine J (2015)

Bottom Line: Radiological and clinical results were analyzed.Patients in OC group had significantly less correction loss and maintained normal sagittal alignment (sagittal vertical axis<5 cm), as compared to patients in UC group (p<0.05).Oswestry disability index (ODI) significantly decreased at last follow-up, as compared to preoperative state.

View Article: PubMed Central - PubMed

Affiliation: Department of Orthopaedic Surgery, Kyung Hee University College of Medicine, Seoul, Korea.

ABSTRACT

Study design: A retrospective comparative study.

Purpose: To provide an ideal correction angle of lumbar lordosis (LL) in degenerative flat back deformity.

Overview of literature: The degree of correction in degenerative flat back in relation to pelvic incidence (PI) remains controversial.

Methods: Forty-nine patients with flat back deformity who underwent corrective surgery were enrolled. Posterior-anterior-posterior sequential operation was performed. Mean age and mean follow-up period was 65.6 years and 24.2 months, respectively. We divided the patients into two groups based on immediate postoperative radiographs-optimal correction (OC) group (PI-9°≤LL

Results: Patients in OC group had significantly less correction loss and maintained normal sagittal alignment (sagittal vertical axis<5 cm), as compared to patients in UC group (p<0.05). LL of low PI group significantly maintained within 9° better than high PI group (p<0.05). Oswestry disability index (ODI) significantly decreased at last follow-up, as compared to preoperative state. However, there was no significant difference in last follow-up ODI between the groups.

Conclusions: In flat back deformity, correction of LL to within 9° of PI will result in better sagittal balance. Thus, we recommend sufficient LL to prevent correction loss, especially in patients with high PI.

No MeSH data available.


Related in: MedlinePlus

A 63-year-old female with degenerative flat back (A) received corrective surgery via 2 staged posterior-anterior-posterior approach. The patient had low pelvic incidence (PI) of 46°. Lumbar lordosis was optimally corrected to 47°, which was within 9° of PI (B). At last follow-up, correction is well maintained with sagittal vertical axis within normal range (<5 cm) (C). Arrows, interbody fusion cage.
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Figure 2: A 63-year-old female with degenerative flat back (A) received corrective surgery via 2 staged posterior-anterior-posterior approach. The patient had low pelvic incidence (PI) of 46°. Lumbar lordosis was optimally corrected to 47°, which was within 9° of PI (B). At last follow-up, correction is well maintained with sagittal vertical axis within normal range (<5 cm) (C). Arrows, interbody fusion cage.

Mentions: Recently, numerous studies emphasized the relevance of LL and corresponding influence of pelvic parameters [18212223], including pelvic incidence (PI), PT, sacral slope, and overhang (Fig. 1). PI is defined as the angle between the perpendicular line to the sacral end plate at its midpoint and the line connecting this point to the axis of the femoral heads [12]. Among the pelvic parameters, PI is the most critical factor because it is the only parameter that is unique to each patient and is independent of the position of the pelvis. In present study, preoperative, postoperative, and last follow-up PI of each individual showed no significant difference, suggestive of constant and unique features. Functionally, PI is closely related to optimal LL [232425]. There have been various attempts to predict LL using pelvic parameters. Legaye et al. [12] measured pelvic parameters in 49 adults free of vertebral disease and demonstrated a predictive equation for lordosis based on the parameters. Moreover, they suggested that a low value of PI implies low values of pelvic parameters and a flattened lordosis, whereas a high value implies well-tilted pelvic orientation and pronounced lordosis [12]. Vialle et al. [13] measured sagittal parameters of 300 asymptomatic volunteers and analyzed the relationships among them to predict maximal LL. Boulay et al. [11] evaluated 149 healthy adults to determine a lordosis predictive equation based on PI. They additionally used T9 tilt to predict LL and claimed that it increased reliability [11]. In 2010, Schwab et al. [15] analyzed radiographic values and ODI of 125 patients with spinal deformity and suggested that realignment objectives should include SVA<5 cm, PT<25°, and LL proportional to the PI (LL=PI±9°) [15]. In our study, patients who were under-corrected eventually had more loss of correction at the last follow-up (57.1%). We focused on the degree of OC of LL to restore normal sagittal alignment. We used Schwab's method (LL=PI±9°), which was relatively simple and tried to realign LL proportional to PI for prediction of target LL. Nevertheless, 14 of 49 patients (29%) were under-corrected (UC group; LL<PI-9°) on immediate postoperative radiographs. Patients in OC group had significantly better maintenance of sagittal balance (SVA≤5 cm) with less correction loss at the last follow-up (p<0.05). Thus it is critical to realign LL proportional to PI, within 9°, to get a satisfactory result (Fig. 2).


Restoration of Lumbar Lordosis in Flat Back Deformity: Optimal Degree of Correction.

Kim KT, Lee SH, Huh DS, Kim HJ, Kim JY, Lee JH - Asian Spine J (2015)

A 63-year-old female with degenerative flat back (A) received corrective surgery via 2 staged posterior-anterior-posterior approach. The patient had low pelvic incidence (PI) of 46°. Lumbar lordosis was optimally corrected to 47°, which was within 9° of PI (B). At last follow-up, correction is well maintained with sagittal vertical axis within normal range (<5 cm) (C). Arrows, interbody fusion cage.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4472583&req=5

Figure 2: A 63-year-old female with degenerative flat back (A) received corrective surgery via 2 staged posterior-anterior-posterior approach. The patient had low pelvic incidence (PI) of 46°. Lumbar lordosis was optimally corrected to 47°, which was within 9° of PI (B). At last follow-up, correction is well maintained with sagittal vertical axis within normal range (<5 cm) (C). Arrows, interbody fusion cage.
Mentions: Recently, numerous studies emphasized the relevance of LL and corresponding influence of pelvic parameters [18212223], including pelvic incidence (PI), PT, sacral slope, and overhang (Fig. 1). PI is defined as the angle between the perpendicular line to the sacral end plate at its midpoint and the line connecting this point to the axis of the femoral heads [12]. Among the pelvic parameters, PI is the most critical factor because it is the only parameter that is unique to each patient and is independent of the position of the pelvis. In present study, preoperative, postoperative, and last follow-up PI of each individual showed no significant difference, suggestive of constant and unique features. Functionally, PI is closely related to optimal LL [232425]. There have been various attempts to predict LL using pelvic parameters. Legaye et al. [12] measured pelvic parameters in 49 adults free of vertebral disease and demonstrated a predictive equation for lordosis based on the parameters. Moreover, they suggested that a low value of PI implies low values of pelvic parameters and a flattened lordosis, whereas a high value implies well-tilted pelvic orientation and pronounced lordosis [12]. Vialle et al. [13] measured sagittal parameters of 300 asymptomatic volunteers and analyzed the relationships among them to predict maximal LL. Boulay et al. [11] evaluated 149 healthy adults to determine a lordosis predictive equation based on PI. They additionally used T9 tilt to predict LL and claimed that it increased reliability [11]. In 2010, Schwab et al. [15] analyzed radiographic values and ODI of 125 patients with spinal deformity and suggested that realignment objectives should include SVA<5 cm, PT<25°, and LL proportional to the PI (LL=PI±9°) [15]. In our study, patients who were under-corrected eventually had more loss of correction at the last follow-up (57.1%). We focused on the degree of OC of LL to restore normal sagittal alignment. We used Schwab's method (LL=PI±9°), which was relatively simple and tried to realign LL proportional to PI for prediction of target LL. Nevertheless, 14 of 49 patients (29%) were under-corrected (UC group; LL<PI-9°) on immediate postoperative radiographs. Patients in OC group had significantly better maintenance of sagittal balance (SVA≤5 cm) with less correction loss at the last follow-up (p<0.05). Thus it is critical to realign LL proportional to PI, within 9°, to get a satisfactory result (Fig. 2).

Bottom Line: Radiological and clinical results were analyzed.Patients in OC group had significantly less correction loss and maintained normal sagittal alignment (sagittal vertical axis<5 cm), as compared to patients in UC group (p<0.05).Oswestry disability index (ODI) significantly decreased at last follow-up, as compared to preoperative state.

View Article: PubMed Central - PubMed

Affiliation: Department of Orthopaedic Surgery, Kyung Hee University College of Medicine, Seoul, Korea.

ABSTRACT

Study design: A retrospective comparative study.

Purpose: To provide an ideal correction angle of lumbar lordosis (LL) in degenerative flat back deformity.

Overview of literature: The degree of correction in degenerative flat back in relation to pelvic incidence (PI) remains controversial.

Methods: Forty-nine patients with flat back deformity who underwent corrective surgery were enrolled. Posterior-anterior-posterior sequential operation was performed. Mean age and mean follow-up period was 65.6 years and 24.2 months, respectively. We divided the patients into two groups based on immediate postoperative radiographs-optimal correction (OC) group (PI-9°≤LL

Results: Patients in OC group had significantly less correction loss and maintained normal sagittal alignment (sagittal vertical axis<5 cm), as compared to patients in UC group (p<0.05). LL of low PI group significantly maintained within 9° better than high PI group (p<0.05). Oswestry disability index (ODI) significantly decreased at last follow-up, as compared to preoperative state. However, there was no significant difference in last follow-up ODI between the groups.

Conclusions: In flat back deformity, correction of LL to within 9° of PI will result in better sagittal balance. Thus, we recommend sufficient LL to prevent correction loss, especially in patients with high PI.

No MeSH data available.


Related in: MedlinePlus